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Sample records for significant pharmacokinetic interactions

  1. Ethanol-drug absorption interaction: potential for a significant effect on the plasma pharmacokinetics of ethanol vulnerable formulations.

    Science.gov (United States)

    Lennernäs, Hans

    2009-01-01

    Generally, gastric emptying of a drug to the small intestine is controlled by gastric motor activity and is the main factor affecting the onset of absorption. Accordingly, the emptying rate from the stomach is mainly affected by the digestive state, the properties of the pharmaceutical formulation and the effect of drugs, posture and circadian rhythm. Variability in the gastric emptying of drugs is reflected in variability in the absorption rate and the shape of the plasma pharmacokinetic profile. When ethanol interacts with an oral controlled release product, such that the mechanism controlling drug release is impaired, the delivery of the dissolved dose into the small intestine and the consequent absorption may result in dangerously high plasma concentrations. For example, the maximal plasma concentration of hydromorphone has individually been shown to be increased as much as 16 times through in vivo testing as a result of this specific pharmacokinetic ethanol-drug formulation interaction. Thus, a pharmacokinetic ethanol-drug interaction is a very serious safety concern when substantially the entire dose from a controlled release product is rapidly emptied into the small intestine (dose dumping), having been largely dissolved in a strong alcoholic beverage in the stomach during a sufficient lag-time in gastric emptying. Based on the literature, a two hour time frame for screening the in vitro dissolution profile of a controlled release product in ethanol concentrations of up to 40% is strongly supported and may be considered as the absolute minimum standard. It is also evident that the dilution, absorption and metabolism of ethanol in the stomach are processes with a minor effect on the local ethanol concentration and that ethanol exposure will be highly dependent on the volume and ethanol concentration of the fluid ingested, together with the rate of intake and gastric emptying. When and in which patients a clinically significant dose dumping will happen is

  2. A blended learning approach to teaching basic pharmacokinetics and the significance of face-to-face interaction.

    Science.gov (United States)

    Edginton, Andrea; Holbrook, Jane

    2010-06-15

    To assess pharmacy students' attitudes towards a blended-learning pharmacokinetics course. Narrated visual presentations and animations that illustrated kinetic processes and guided students through the use of software programs used for calculations were created. Other learning techniques used included online self-assessment quizzes, practice problem sets, and weekly face-to-face problem-solving tutorials. A precourse questionnaire to assess students' level of enthusiasm towards the blended-learning course and to solicit any concerns they had was administered at the beginning of the course. A postcourse questionnaire that included the same 4 Likert-scale items from the precourse questionnaire and follow-up open-ended questions was administered. Individual changes in level of enthusiasm were compared for individuals who completed both the precourse and postcourse questionnaire. Students' concerns about the blended method of learning had decreased postcourse while their enthusiasm for the benefits of blended learning had increased. Students' initial concerns about the blended learning experience were focused on their ability to communicate with the instructor about the online components, but shifted to their own time management skills at the end of the course. Face-to-face interactions with each other and with the instructor were more highly rated than online interactions in this course.

  3. A proposal for a pharmacokinetic interaction significance classification system (PISCS) based on predicted drug exposure changes and its potential application to alert classifications in product labelling.

    Science.gov (United States)

    Hisaka, Akihiro; Kusama, Makiko; Ohno, Yoshiyuki; Sugiyama, Yuichi; Suzuki, Hiroshi

    2009-01-01

    Pharmacokinetic drug-drug interactions (DDIs) are one of the major causes of adverse events in pharmacotherapy, and systematic prediction of the clinical relevance of DDIs is an issue of significant clinical importance. In a previous study, total exposure changes of many substrate drugs of cytochrome P450 (CYP) 3A4 caused by coadministration of inhibitor drugs were successfully predicted by using in vivo information. In order to exploit these predictions in daily pharmacotherapy, the clinical significance of the pharmacokinetic changes needs to be carefully evaluated. The aim of the present study was to construct a pharmacokinetic interaction significance classification system (PISCS) in which the clinical significance of DDIs was considered with pharmacokinetic changes in a systematic manner. Furthermore, the classifications proposed by PISCS were compared in a detailed manner with current alert classifications in the product labelling or the summary of product characteristics used in Japan, the US and the UK. A matrix table was composed by stratifying two basic parameters of the prediction: the contribution ratio of CYP3A4 to the oral clearance of substrates (CR), and the inhibition ratio of inhibitors (IR). The total exposure increase was estimated for each cell in the table by associating CR and IR values, and the cells were categorized into nine zones according to the magnitude of the exposure increase. Then, correspondences between the DDI significance and the zones were determined for each drug group considering the observed exposure changes and the current classification in the product labelling. Substrate drugs of CYP3A4 selected from three therapeutic groups, i.e. HMG-CoA reductase inhibitors (statins), calcium-channel antagonists/blockers (CCBs) and benzodiazepines (BZPs), were analysed as representative examples. The product labelling descriptions of drugs in Japan, US and UK were obtained from the websites of each regulatory body. Among 220

  4. An interactive program for pharmacokinetic modeling.

    Science.gov (United States)

    Lu, D R; Mao, F

    1993-05-01

    A computer program, PharmK, was developed for pharmacokinetic modeling of experimental data. The program was written in C computer language based on the high-level user-interface Macintosh operating system. The intention was to provide a user-friendly tool for users of Macintosh computers. An interactive algorithm based on the exponential stripping method is used for the initial parameter estimation. Nonlinear pharmacokinetic model fitting is based on the maximum likelihood estimation method and is performed by the Levenberg-Marquardt method based on chi 2 criterion. Several methods are available to aid the evaluation of the fitting results. Pharmacokinetic data sets have been examined with the PharmK program, and the results are comparable with those obtained with other programs that are currently available for IBM PC-compatible and other types of computers.

  5. Pharmacokinetic and pharmacodynamic drug interactions with ethanol (alcohol).

    Science.gov (United States)

    Chan, Lingtak-Neander; Anderson, Gail D

    2014-12-01

    Ethanol (alcohol) is one of the most widely used legal drugs in the world. Ethanol is metabolized by alcohol dehydrogenase (ADH) and the cytochrome P450 (CYP) 2E1 drug-metabolizing enzyme that is also responsible for the biotransformation of xenobiotics and fatty acids. Drugs that inhibit ADH or CYP2E1 are the most likely theoretical compounds that would lead to a clinically significant pharmacokinetic interaction with ethanol, which include only a limited number of drugs. Acute ethanol primarily alters the pharmacokinetics of other drugs by changing the rate and extent of absorption, with more limited effects on clearance. Both acute and chronic ethanol use can cause transient changes to many physiologic responses in different organ systems such as hypotension and impairment of motor and cognitive functions, resulting in both pharmacokinetic and pharmacodynamic interactions. Evaluating drug interactions with long-term use of ethanol is uniquely challenging. Specifically, it is difficult to distinguish between the effects of long-term ethanol use on liver pathology and chronic malnutrition. Ethanol-induced liver disease results in decreased activity of hepatic metabolic enzymes and changes in protein binding. Clinical studies that include patients with chronic alcohol use may be evaluating the effects of mild cirrhosis on liver metabolism, and not just ethanol itself. The definition of chronic alcohol use is very inconsistent, which greatly affects the quality of the data and clinical application of the results. Our study of the literature has shown that a significantly higher volume of clinical studies have focused on the pharmacokinetic interactions of ethanol and other drugs. The data on pharmacodynamic interactions are more limited and future research addressing pharmacodynamic interactions with ethanol, especially regarding the non-central nervous system effects, is much needed.

  6. Pharmacokinetic interaction between scutellarin and valsartan in rats.

    Science.gov (United States)

    Cui, Ming-Yu; Tian, Chong-Chong; Ju, Ai-Xia; Zhang, Chun-Ting; Li, Qiu-Hong

    2013-04-01

    Scutellarin is the main effective constituent of breviscapine, a flavonoid mixture isolated from the dried whole plant of Erigeron breviscapus (Vant.) Hand-Mazz, and valsartan is used as an antihypertensive drug. These two drugs have already been clinically used together to treat diabetic nephropathy (DN) in China, and the combined medications showed some enhanced protection against DN. The aim of this study is to investigate the potential pharmacokinetic interaction between scutellarin and valsartan in rats. Breviscapine injection (20 mg x kg(-1), i.v.) and valsartan (15 mg x kg-, i.g.), either alone or together were given to 18 male Sprague-Dawley rats. Concentrations of scutellarin and valsartan were quantified by HPLC, and pharmacokinetic parameters were calculated by non-compartmental methods. We found that the pharmacokinetic parameters of scutellarin altered significantly after co-administration of oral valsartan. The plasma clearance (CL(p)) and the bile clearance (CL(b)) of scutellarin were reduced significantly in the presence of valsartan. After oral administration of valsartan with or without intravenous scutellarin, however, the pharmacokinetic parameters of valsartan were comparable. In conclusion, our data suggests that the concurrent use of valsartan reduces the biliary excretion of scutellarin, and this may be due to the inhibitory effect of valsartan on the biliary excretion of scutellarin mediated by Mrp2 (Multidrug resistance-associated protein 2).

  7. [Pharmacokinetic interactions of telaprevir with other drugs].

    Science.gov (United States)

    Berenguer Berenguer, Juan; González-García, Juan

    2013-07-01

    Telaprevir is a new direct-acting antiviral drug for the treatment of hepatitis C virus (HCV) infection and is both a substrate and an inhibitor of cytochrome P450 (CYP450) isoenzymes. With the introduction of this new drug, assessment of drug-drug interactions has become a key factor in the evaluation of patients under treatment for HCV infection. During the treatment of this infection, many patients require other drugs to mitigate the adverse effects of anti-HCV drugs and to control other comorbidities. Moreover, most patients coinfected with HIV and HCV require antiretroviral therapy during treatment for HCV. Physicians should therefore be familiar with the pharmacokinetic properties of direct-acting antivirals for HCV treatment and their potential drug-drug interactions. The present article reviews the available information to date on the interactions of telaprevir with other drugs and provides recommendations for daily clinical practice. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  8. Pharmacokinetics of Anti-Epileptic Drugs and their Clinical Significance

    Directory of Open Access Journals (Sweden)

    Svein I. Johannessen

    1990-01-01

    Full Text Available The serum concentration achieved and maintained following the administration of a fixed drug dosage is a direct consequence of the interactions of a wide variety of interrelated processes, including drug absorption, distribution, metabolism, and excretion, and the physiological status of the patient. These interrelationships are reviewed with specific reference to the major anti-epileptic drugs, phenobarbitone, phenytoin, sodium valproate, and carbamazepine, as well as a new first-line antiepileptic, oxcarbazepine. Both older drugs, such as phenobarbitone and phenytoin, and newer drugs, such as carbamazepine (CBZ and sodium valproate, have been studied extensively over the past years giving valuable information for drug treatment. An important feature of oxcarbazepine (OXC , which was developed through minimal changes in the structure of CBZ in order to improve on the tolerability of CBZ without sacrificing efficacy, is that its metabolites do not include the 11-epoxide which has been implicated in the side-effects of CBZ. In man, OXC is metabolized to a monohydroxy derivative which has independent anti-epileptic properties. OXC seems to lack several disadavantageous pharmacokinetic properties common to other major anti-epileptic drugs. OXC does not influence its own metabolism after repeated administration, in contrast to the auto-induction displayed by CBZ. The metabolism of OXC is not influenced by anti-epileptic co-medication and does not influence the kinetics of other anti-epileptic drugs – or if it does, then to a lesser extent than CBZ.

  9. ABT-773: pharmacokinetics and interactions with ranitidine and sucralfate.

    Science.gov (United States)

    Pletz, M W; Preechachatchaval, V; Bulitta, J; Allewelt, M; Burkhardt, O; Lode, H

    2003-03-01

    We assessed the pharmacokinetics and interaction of ABT-773 in 12 volunteers receiving ABT-773 alone or concomitantly with ranitidine or sucralfate. Data for 150 mg of ABT-773 were as follows: the maximum concentration of the drug in plasma (C(max)) was 318 ng/ml, its half-life was 5.66 h, and its area under the plasma concentration-time curve from 0 h to infinity (AUC(0- infinity )) was 1,662 ng. h/ml. Coadministration of ranitidine, reduced the C(max) (-25.7%) and AUC(0- infinity ) (-15.8%) significantly. Sucralfate had no impact on the bioavailability of ABT-773.

  10. Pharmacokinetic Interaction between Magnolol and Piperine in Rats ...

    African Journals Online (AJOL)

    Purpose: To investigate the pharmacokinetic mechanism of interaction between magnolol and piperine when co-administered to rats. Methods: The rats were divided into five groups as follows: magnolol group (625 mg/kg); low dose of piperine group (20 mg/kg); high dose of piperine group (40 mg/kg); low dose of piperine ...

  11. Pharmacokinetic interaction between corticosteroids and tacrolimus after renal transplantation.

    Science.gov (United States)

    Anglicheau, Dany; Flamant, Martin; Schlageter, Marie Hélène; Martinez, Frank; Cassinat, Bruno; Beaune, Philippe; Legendre, Christophe; Thervet, Eric

    2003-11-01

    Tacrolimus is an immunosuppressive drug that is a substrate of cytochrome P450 3A (CYP3A) enzymes and P-glycoprotein (P-gp). After transplantation, many pharmacological interactions have been described. Corticosteroids induce both CYP3A and P-gp activity. This study was designed to investigate the presence of a clinically significant interaction between steroids and tacrolimus after renal transplantation. We studied 83 renal transplant recipients receiving tacrolimus after transplantation. Patients were divided into three groups, according to steroid dose (low: 0-0.15 mg/kg/day; intermediate: 0.16-0.25 mg/kg/day; and high: >0.25 mg/kg/day). All other medications, including those known to interact with CYP3A and/or P-gp, were recorded. Steroid dosage, tacrolimus dosage, tacrolimus trough concentration (C0) and tacrolimus concentration/dose ratio [C0 divided by the 24 h dosage (mg/kg)] were assessed for each dosage group after 1 and 3 months of tacrolimus treatment. The three groups were not different as regards the use of non-immunosuppressive treatments or clinical events. At 1 and 3 months, the tacrolimus doses and concentration/dose ratios differed significantly in the three steroid dosage groups. With the higher doses, higher tacrolimus doses were needed to achieve the blood tacrolimus targeted trough level. We demonstrated that pharmacokinetic interaction occurs between steroids and tacrolimus in renal transplant patients. The higher the steroid dosage, the higher the dosage of tacrolimus needed to achieve target trough levels in these patients. The most likely interaction mechanism is specific enzymatic induction of CYP3A and/or P-gp. Interaction is present, even when the steroid dosage is low. The clinical events liable to occur during steroid sparing or tapering must be taken into account because it may be associated with episodes of tacrolimus-related nephrotoxicity.

  12. Pharmacokinetic Herb-Drug Interactions: Insight into Mechanisms and Consequences.

    Science.gov (United States)

    Oga, Enoche F; Sekine, Shuichi; Shitara, Yoshihisa; Horie, Toshiharu

    2016-04-01

    Herbal medicines are currently in high demand, and their popularity is steadily increasing. Because of their perceived effectiveness, fewer side effects and relatively low cost, they are being used for the management of numerous medical conditions. However, they are capable of affecting the pharmacokinetics and pharmacodynamics of coadministered conventional drugs. These interactions are particularly of clinically relevance when metabolizing enzymes and xenobiotic transporters, which are responsible for the fate of many drugs, are induced or inhibited, sometimes resulting in unexpected outcomes. This article discusses the general use of herbal medicines in the management of several ailments, their concurrent use with conventional therapy, mechanisms underlying herb-drug interactions (HDIs) as well as the drawbacks of herbal remedy use. The authors also suggest means of surveillance and safety monitoring of herbal medicines. Contrary to popular belief that "herbal medicines are totally safe," we are of the view that they are capable of causing significant toxic effects and altered pharmaceutical outcomes when coadministered with conventional medicines. Due to the paucity of information as well as sometimes conflicting reports on HDIs, much more research in this field is needed. The authors further suggest the need to standardize and better regulate herbal medicines in order to ensure their safety and efficacy when used alone or in combination with conventional drugs.

  13. Pharmacokinetic interactions between contraceptives and antiepileptic drugs

    DEFF Research Database (Denmark)

    Sabers, A.

    2008-01-01

    The occurrence of bi-directional drug interactions between antiepileptic drugs (AEDs) and combined oral contraceptives (M) pose potential risks of unintended pregnancy and as well as seizure deterioration. It is well established that several of the older AEDs (carbamazepine, phenytoin...... AEDs, which undergoes glucuronidation processes, such as valproate and oxcarbazepine, may be affected by OCs. The magnitude of the drug-drug interactions show in general wide inter-individual variability and the change in the elimination rate is often unpredictable and can be influenced by a number...... of co-variants such as co-medication of other drugs, as well as genetic and environmental factors. It is therefore recommended that change in OC use is assisted by AED monitoring whenever possible. (C) 2007 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved Udgivelsesdato: 2008/3...

  14. Classification and occurrence of clinically significant drug interactions with irinotecan and oxaliplatin in patients with metastatic colorectal cancer

    NARCIS (Netherlands)

    Jansman, FGA; Idzinga, FSF; Smit, WM; de Graaf, JC; Coenen, JLLM; Sleijfer, DT; Brouwers, JRBJ

    Background: Pharmacokinetic and pharmacodynamic drug interactions with cytotoxic drugs may significantly influence the efficacy and toxicity of chemotherapy. Objective: The purpose of this study was to identify drug interactions with irinotecan and oxaliplatin reported in the literature, to assess

  15. Excipient-drug pharmacokinetic interactions: Effect of disintegrants on efflux across excised pig intestinal tissues

    Directory of Open Access Journals (Sweden)

    Werner Gerber

    2018-04-01

    Full Text Available Pharmaceutical excipients were designed originally to be pharmacologically inert. However, certain excipients were found to have altering effects on drug pharmacodynamics and/or pharmacokinetics. Pharmacokinetic interactions may be caused by modulation of efflux transporter proteins, intercellular tight junctions and/or metabolic enzyme amongst others. In this study, five disintegrants from different chemical classes were evaluated for P-glycoprotein (P-gp related inhibition and tight junction modulation effects. Bi-directional transport studies of the model compound, Rhodamine 123 (R123 were conducted in the absence (control group and presence (experimental groups of four concentrations of each selected disintegrant across excised pig jejunum tissue. The results showed that some of the selected disintegrants (e.g. Ac-di-sol® and Kollidon® CL-M increased R123 absorptive transport due to inhibition of P-gp related efflux, while another disintegrant (e.g. sodium alginate changed R123 transport due to inhibition of P-gp in conjunction with a transient opening of the tight junctions in a concentration dependent way. It may be concluded that the co-application of some disintegrants to the intestinal epithelium may lead to pharmacokinetic interactions with drugs that are susceptible to P-gp related efflux. However, the clinical significance of these in vitro permeation findings should be confirmed by means of in vivo studies. Keywords: Disintegrants, Excipient, Ex vivo, P-glycoprotein, Pharmacokinetic interactions, Rhodamine 123

  16. Pharmacokinetic interaction of enrofloxacin/trimethoprim combination following single-dose intraperitoneal and oral administration in rats.

    Science.gov (United States)

    Choi, Myung-Jin; Yohannes, Sileshi Belew; Lee, Seung-Jin; Damte, Dereje; Kim, Jong-Choon; Suh, Joo-Won; Park, Seung-Chun

    2014-03-01

    The pharmacokinetic interaction of enrofloxacin and trimethoprim was evaluated after single-dose intraperitoneal or oral co-administration in rats. Plasma concentrations of the two drugs were determined by high-performance liquid chromatography. Following intraperitoneal combination, a significant (P trimethoprim, respectively. There was a significant (P trimethoprim. Further study is recommended in other species of animals.

  17. [Role of food interaction pharmacokinetic studies in drug development. Food interaction studies of theophylline and nifedipine retard and buspirone tablets].

    Science.gov (United States)

    Drabant, S; Klebovich, I; Gachályi, B; Renczes, G; Farsang, C

    1998-09-01

    Due to several mechanism, meals may modify the pharmacokinetics of drug products, thereby eliciting to clinically significant food interaction. Food interactions with the drug substance and with the drug formulation should be distinguished. Food interaction of different drug products containing the same active ingredient can be various depending on the pharmaceutical formulation technology. Particularly, in the case of modified release products, the food/formulation interaction can play an important role in the development of food interaction. Well known example, that bioavailability of theophylline can be influenced in different way (either increased, decreased or unchanged) by concomitant intake of food in the case of different sustained release products. The role and methods of food interaction studies in the different kinds of drug development (new chemical entity, modified release products, generics) are reviewed. Prediction of food effect response on the basis of the physicochemical and pharmacokinetic characteristics of the drug molecule or formulations is discussed. The results of three food interaction studies carried out the products of EGIS Pharmaceuticals Ltd. are also reviewed. The pharmacokinetic parameters of theophyllin 400 mg retard tablet were practically the same in both fasting condition and administration after consumption of a high fat containing standard breakfast. The ingestion of a high fat containing breakfast, increased the AUC of nifedipine from 259.0 +/- 101.2 ng h/ml to 326.7 +/- 122.5 ng h/ml and Cmax from 34.5 +/- 15.9 ng/ml to 74.3 +/- 23.9 ng/ml in case of nifedipine 20 mg retard tablet, in agreement with the data of literature. The statistical evaluation indicated significant differences between the pharmacokinetic parameters in the case of two administrations (before and after meal). The effect of a high fat containing breakfast for a generic version of buspiron 10 mg tablet and the bioequivalence after food consumption were

  18. Evaluation of the Potential Pharmacokinetic Interaction between Atomoxetine and Fluvoxamine in Healthy Volunteers.

    Science.gov (United States)

    Todor, Ioana; Popa, Adina; Neag, Maria; Muntean, Dana; Bocsan, Corina; Buzoianu, Anca; Vlase, Laurian; Gheldiu, Ana-Maria; Briciu, Corina

    2017-01-01

    Attention deficit hyperactivity disorder (ADHD) is frequently associated with other psychiatric pathologies. Therefore, the present study investigated a possible pharmacokinetic interaction between atomoxetine (ATX), a treatment option for ADHD, and an antidepressant, namely, fluvoxamine (FVX). Designed as an open-label, non-randomized clinical trial, the study included 2 periods. In period 1 (reference), each subject received ATX 25 mg (single-dose), whereas in period 2 (test), all subjects were given a combination of ATX 25 mg + FVX 100 mg, following a 6-day pretreatment regimen with the enzymatic inhibitor. Non-compartmental methods were employed to determine the pharmacokinetic parameters of ATX and its main active metabolite (glucuronidated form), 4-hydroxyatomoxetine-O-glucuronide. The results revealed significant differences between the study periods for Cmax, AUC0-t and AUC0-∞ values corresponding to ATX and its metabolite. Small, but statistically significant increases in AUC values were reported for both parent drug (1,583.05 ± 1,040.29 vs. 2,111.55 ± 1,411.59 ng*h/ml) and 4-hydroxyatomoxetine-O-glucuronide (5,754.71 ± 1,235.5 vs. 6,293.17 ± 1,219.34 ng*h/ml) after combined treatment of ATX and the enzymatic inhibitor. FVX had a modest effect on the pharmacokinetics of ATX and 4-hydroxyatomoxetine-O-glucuronide. The presence or absence of any clinical consequences associated with this pharmacokinetic drug-drug interaction needs to be established in future studies. © 2016 S. Karger AG, Basel.

  19. A pharmacokinetic and pharmacodynamic drug interaction between rosuvastatin and valsartan in healthy subjects.

    Science.gov (United States)

    Jung, Jin Ah; Lee, Soo-Yun; Kim, Jung-Ryul; Ko, Jae-Wook; Jang, Seong Bok; Nam, Su Youn; Huh, Wooseong

    2015-01-01

    Valsartan, an angiotensin-receptor blocker, and rosuvastatin, a competitive inhibitor of the 3-hydroxy-3-methylglutaryl coenzyme A reductase, are frequently coadministered to treat patients with hypertension and dyslipidemia. The study reported here sought to evaluate the pharmacokinetic and pharmacodynamic interactions between rosuvastatin and valsartan in healthy Korean subjects. Thirty healthy male Korean subjects were administered with rosuvastatin (20 mg/day), valsartan (160 mg/day), and both drugs concomitantly for 4 days in a randomized, open-label, multiple-dose, three-treatment, three-period crossover study. Plasma concentrations of rosuvastatin, N-desmethyl rosuvastatin, and valsartan were determined using validated high-performance liquid chromatography with tandem mass spectrometry. Lipid profiles and vital signs (systolic and diastolic blood pressure and pulse rate) were measured for the pharmacodynamic assessment. For rosuvastatin, the geometric mean ratios (90% confidence intervals [CIs]) of coadministration to mono-administration were 0.8809 (0.7873-0.9857) for maximum plasma concentration at steady state and 0.9151 (0.8632-0.9701) for area under the concentration-time curve (AUC) over a dosing interval at steady state. For valsartan, the geometric mean ratios (90% CIs) of those were 0.9300 (0.7946-1.0884) and 1.0072 (0.8893-1.1406), respectively. There were no significant differences in the metabolic ratio of N-desmethyl rosuvastatin AUC to rosuvastatin AUC between coadministration and rosuvastatin alone. No interaction was found in terms of systolic or diastolic blood pressure or lipid profiles. Combined treatment with valsartan and rosuvastatin was generally well tolerated without serious adverse events. The pharmacokinetic profiles of rosuvastatin and valsartan in combination were comparable with those of rosuvastatin and valsartan administered individually, suggesting that their individual pharmacokinetics were not affected by their

  20. No significant effect of the SLCO1B1 polymorphism on the pharmacokinetics of ursodeoxycholic acid.

    Science.gov (United States)

    Xiang, Xiaoqiang; Vakkilainen, Juha; Backman, Janne T; Neuvonen, Pertti J; Niemi, Mikko

    2011-11-01

    To investigate possible effects of the SLCO1B1 polymorphism on the pharmacokinetics of ursodeoxycholic acid (UDCA) and its metabolites in healthy volunteers. In a crossover study with two phases, 15 healthy volunteers with the SLCO1B1*1A/*1A genotype, seven with the *1B/*1B genotype, and five with the *15/*15 or *5/*15 genotype ingested placebo or a single 150-mg dose of UDCA. Plasma concentrations of bile acids and their biosynthesis marker were determined up to 24 h post-ingestion by liquid chromatography-tandem mass spectrometry. The SLCO1B1 genotype had no significant effect on the pharmacokinetics of UDCA. The geometric mean ratios (95% confidence interval) of UDCA area under the plasma concentration-time curve from 0 to 12 h (AUC(0-12)) in subjects with the SLCO1B1*1B/*1B genotype and in subjects with the SLCO1B1*15/*15 or *5/*15 genotype to the AUC(0-12) in subjects with the SLCO1B1*1A/*1A genotype were 1.07 (0.85, 1.35; P = 0.459) and 0.93 (0.75, 1.15; P = 0.563), respectively. In addition, following either placebo or UDCA administration, the SLCO1B1 polymorphism showed no association with the AUC(0-24) of the glycine and taurine conjugates of UDCA, with endogenous bile acids, or with the incremental AUC(0-24) of a bile acid synthesis marker. Compared with placebo, UDCA ingestion increased the AUC(0-24) of cholic acid, glycochenodeoxycholic acid, glycocholic acid, and glycodeoxycholic acid by 1.5-, 1.1-, 1.2-, and 1.2- fold (P acids.

  1. PHARMACOKINETIC-PHARMACODYNAMIC DRUG-INTERACTIONS WITH NONSTEROIDAL ANTIINFLAMMATORY DRUGS

    NARCIS (Netherlands)

    BROUWERS, JRBJ; DESMET, PAGM

    1994-01-01

    The nonsteroidal anti-inflammatory drugs (NSAIDs) are very commonly prescribed, especially in the elderly population. In many countries more than 10 different NSAIDs are available. As the older pyrazole compounds like phenylbutazone, oxyphenbutazone and azapropazone are most prone to pharmacokinetic

  2. A pharmacokinetic and pharmacodynamic drug interaction between rosuvastatin and valsartan in healthy subjects

    Directory of Open Access Journals (Sweden)

    Jung JA

    2015-03-01

    Full Text Available Jin Ah Jung,1 Soo-Yun Lee,2 Jung-Ryul Kim,1 Jae-Wook Ko,1,2 Seong Bok Jang,3 Su Youn Nam,3 Wooseong Huh1,41Department of Clinical Pharmacology and Therapeutics, Samsung Medical Center, 2Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, 3Yuhan Research Institute, Yuhan Corporation, 4Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, KoreaPurpose: Valsartan, an angiotensin-receptor blocker, and rosuvastatin, a competitive inhibitor of the 3-hydroxy-3-methylglutaryl coenzyme A reductase, are frequently coadministered to treat patients with hypertension and dyslipidemia. The study reported here sought to evaluate the pharmacokinetic and pharmacodynamic interactions between rosuvastatin and valsartan in healthy Korean subjects. Subjects and methods: Thirty healthy male Korean subjects were administered with rosuvastatin (20 mg/day, valsartan (160 mg/day, and both drugs concomitantly for 4 days in a randomized, open-label, multiple-dose, three-treatment, three-period crossover study. Plasma concentrations of rosuvastatin, N-desmethyl rosuvastatin, and valsartan were determined using validated high-performance liquid chromatography with tandem mass spectrometry. Lipid profiles and vital signs (systolic and diastolic blood pressure and pulse rate were measured for the pharmacodynamic assessment.Results: For rosuvastatin, the geometric mean ratios (90% confidence intervals [CIs] of coadministration to mono-administration were 0.8809 (0.7873-0.9857 for maximum plasma concentration at steady state and 0.9151 (0.8632-0.9701 for area under the concentration–time curve (AUC over a dosing interval at steady state. For valsartan, the geometric mean ratios (90% CIs of those were 0.9300 (0.7946-1.0884 and 1.0072 (0.8893-1.1406, respectively. There were no significant differences in the metabolic ratio of N

  3. Investigation of a Potential Pharmacokinetic Interaction Between Nebivolol and Fluvoxamine in Healthy Volunteers.

    Science.gov (United States)

    Gheldiu, Ana-Maria; Vlase, Laurian; Popa, Adina; Briciu, Corina; Muntean, Dana; Bocsan, Corina; Buzoianu, Anca; Achim, Marcela; Tomuta, Ioan; Todor, Ioana; Neag, Maria

    2017-01-01

    To investigate whether fluvoxamine coadministration can influence the pharmacokinetic properties of nebivolol and its active hydroxylated metabolite (4-OH-nebivolol) and to assess the consequences of this potential pharmacokinetic interaction upon nebivolol pharmacodynamics. This open-label, non-randomized, sequential clinical trial consisted of two periods: Period 1 (Reference), during which each volunteer received a single dose of 5 mg nebivolol and Period 2 (Test), when a combination of 5 mg nebivolol and 100 mg fluvoxamine was given to all subjects, after a 6-days pretreatment regimen with fluvoxamine (50-100 mg/day). Non-compartmental analysis was used to determine the pharmacokinetic parameters of nebivolol and its active metabolite. The pharmacodynamic parameters (blood pressure and heart rate) were assessed at rest after each nebivolol intake, during both study periods. Fluvoxamine pretreatment increased Cmax and AUC0-∞  of nebivolol (Cmax: 1.67 ± 0.690  vs 2.20 ± 0.970  ng/mL; AUC0-∞: 12.1 ± 11.0  vs 19.3 ± 19.5  ng*h/mL ) and of its active metabolite (Cmax: 0.680  ± 0.220  vs 0.960 ± 0.290  ng/mL; AUC0-∞: 17.6 ±20.1  vs 25.5 ± 29.9  ng*h/mL). Apart from Cmax,AUC0-t and AUC0-∞, the other pharmacokinetic parameters (tmax, kel and t½) were not significantly different between study periods. As for the pharmacodynamic analysis, decreases in blood pressure and heart rate after nebivolol administration were similar with and without fluvoxamine concomitant intake. Due to enzymatic inhibition, fluvoxamine increases the exposure to nebivolol and its active hydroxylated metabolite in healthy volunteers. This did not influence the blood pressure and heart-rate lowering effects of the beta-blocker administered as single-dose. However, more detail studies involving actual patients are required to further investigate the clinical relevance of this drug interaction. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For

  4. Pharmacokinetic and Pharmacodynamic Interaction of Andrographolide and Standardized Extract of Andrographis paniculata (Nees) with Nabumetone in Wistar Rats.

    Science.gov (United States)

    Balap, Aishwarya; Lohidasan, Sathiyanarayanan; Sinnathambi, Arulmozhi; Mahadik, Kakasaheb

    2017-01-01

    The aim of the study was to investigate the herb-drug interaction of Andrographis paniculata Nees (Acanthaceae) and Andrographolide (AN) with nabumetone (NAB) in wistar rats. Pharmacokinetic and pharmacodynamic interactions were studied after co-administration of APE and AN with NAB in Wistar rats. In pharmacokinetic studies, significant decrease in Cmax, AUC 0-t and AUC 0-∞ of 6-MNA after co-administration with pure AN and APE has been observed. T max of 6-MNA has been increased to 2 h from 1.5 h in AN + NAB treated group. Changes in mean residential time, clearance and volume of distribution of 6-MNA in APE + NAB treated group and AN + NAB treated group indicated interference of other components of APE other than AN. In pharmacodynamic study, significant decrease in antiarthritic activity of NAB on concomitant administration with APE and AN has been observed. The study concludes that NAB exhibits pharmacokinetic and pharmacodynamic interactions with APE and AN in rats thus alarms the concomitant use of herbal preparations containing APE and AN with NAB. Further study is needed to understand the mechanism and predict the herb-drug interaction in humans. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Pharmacokinetic Interactions between Drugs and Botanical Dietary Supplements.

    Science.gov (United States)

    Sprouse, Alyssa A; van Breemen, Richard B

    2016-02-01

    The use of botanical dietary supplements has grown steadily over the last 20 years despite incomplete information regarding active constituents, mechanisms of action, efficacy, and safety. An important but underinvestigated safety concern is the potential for popular botanical dietary supplements to interfere with the absorption, transport, and/or metabolism of pharmaceutical agents. Clinical trials of drug-botanical interactions are the gold standard and are usually carried out only when indicated by unexpected consumer side effects or, preferably, by predictive preclinical studies. For example, phase 1 clinical trials have confirmed preclinical studies and clinical case reports that St. John's wort (Hypericum perforatum) induces CYP3A4/CYP3A5. However, clinical studies of most botanicals that were predicted to interact with drugs have shown no clinically significant effects. For example, clinical trials did not substantiate preclinical predictions that milk thistle (Silybum marianum) would inhibit CYP1A2, CYP2C9, CYP2D6, CYP2E1, and/or CYP3A4. Here, we highlight discrepancies between preclinical and clinical data concerning drug-botanical interactions and critically evaluate why some preclinical models perform better than others in predicting the potential for drug-botanical interactions. Gaps in knowledge are also highlighted for the potential of some popular botanical dietary supplements to interact with therapeutic agents with respect to absorption, transport, and metabolism. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  6. Pharmacokinetic Interactions between Drugs and Botanical Dietary Supplements

    Science.gov (United States)

    Sprouse, Alyssa A.

    2016-01-01

    The use of botanical dietary supplements has grown steadily over the last 20 years despite incomplete information regarding active constituents, mechanisms of action, efficacy, and safety. An important but underinvestigated safety concern is the potential for popular botanical dietary supplements to interfere with the absorption, transport, and/or metabolism of pharmaceutical agents. Clinical trials of drug–botanical interactions are the gold standard and are usually carried out only when indicated by unexpected consumer side effects or, preferably, by predictive preclinical studies. For example, phase 1 clinical trials have confirmed preclinical studies and clinical case reports that St. John’s wort (Hypericum perforatum) induces CYP3A4/CYP3A5. However, clinical studies of most botanicals that were predicted to interact with drugs have shown no clinically significant effects. For example, clinical trials did not substantiate preclinical predictions that milk thistle (Silybum marianum) would inhibit CYP1A2, CYP2C9, CYP2D6, CYP2E1, and/or CYP3A4. Here, we highlight discrepancies between preclinical and clinical data concerning drug–botanical interactions and critically evaluate why some preclinical models perform better than others in predicting the potential for drug–botanical interactions. Gaps in knowledge are also highlighted for the potential of some popular botanical dietary supplements to interact with therapeutic agents with respect to absorption, transport, and metabolism. PMID:26438626

  7. Pharmacokinetic drug interactions of antimicrobial drugs : a systematic review on oxazolidinones, rifamycines, macrolides, fluoroquinolones, and Beta-lactams

    NARCIS (Netherlands)

    Bolhuis, Mathieu S; Panday, Prashant N; Pranger, Arianna D; Kosterink, Jos G W; Alffenaar, Jan-Willem C

    2011-01-01

    Like any other drug, antimicrobial drugs are prone to pharmacokinetic drug interactions. These drug interactions are a major concern in clinical practice as they may have an effect on efficacy and toxicity. This article provides an overview of all published pharmacokinetic studies on drug

  8. Clinical Drug-Drug Pharmacokinetic Interaction Potential of Sucralfate with Other Drugs: Review and Perspectives.

    Science.gov (United States)

    Sulochana, Suresh P; Syed, Muzeeb; Chandrasekar, Devaraj V; Mullangi, Ramesh; Srinivas, Nuggehally R

    2016-10-01

    Sucralfate, a complex of aluminium hydroxide with sulfated sucrose, forms a strong gastrointestinal tract (GIT) mucosal barrier with excellent anti-ulcer property. Because sucralfate does not undergo any significant oral absorption, sucralfate resides in the GIT for a considerable length of time. The unabsorbed sucralfate may alter the pharmacokinetics of the oral drugs by impeding its absorption and reducing the oral bioavailability. Because of the increased use of sucralfate, it was important to provide a reappraisal of the published clinical drug-drug interaction studies of sucralfate with scores of drugs. This review covers several category of drugs such as non-steroidal anti-inflammatory drugs, fluoroquinolones, histamine H2-receptor blockers, macrolides, anti-fungals, anti-diabetics, salicylic acid derivatives, steroidal anti-inflammatory drugs and provides pharmacokinetic data summary along with study design, objectives and key remarks. While the loss of oral bioavailability was significant for the fluoroquinolone class, it generally varied for other classes of drugs, suggesting that impact of the co-administration of sucralfate is manageable in clinical situations. Given the technology advancement in formulation development, it may be in order feasible to develop appropriate formulation strategies to either avoid or minimize the absorption-related issues when co-administered with sucralfate. It is recommended that consideration of both in vitro and preclinical studies may be in order to gauge the level of interaction of a drug with sucralfate. Such data may aid in the development of appropriate strategies to navigate the co-administration of sucralfate with other drugs in this age of polypharmacy.

  9. Potential pharmacokinetic interactions between antiretrovirals and medicinal plants used as complementary and African traditional medicines.

    Science.gov (United States)

    Müller, Adrienne C; Kanfer, Isadore

    2011-11-01

    The use of traditional/complementary/alternate medicines (TCAMs) in HIV/AIDS patients who reside in Southern Africa is quite common. Those who use TCAMs in addition to antiretroviral (ARV) treatment may be at risk of experiencing clinically significant pharmacokinetic (PK) interactions, particularly between the TCAMs and the protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). Mechanisms of PK interactions include alterations to the normal functioning of drug efflux transporters, such as P-gp and/or CYP isoenzymes, such a CYP3A4 that mediate the absorption and elimination of drugs in the small intestine and liver. Specific mechanisms include inhibition and activation of these proteins and induction via the pregnane X receptor (PXR). Several clinical studies and case reports involving ARV-herb PK interactions have been reported. St John's Wort, Garlic and Cat's Claw exhibited potentially significant interactions, each with a PI or NNRTI. The potential for these herbs to induce PK interactions with drugs was first identified in reports of in vitro studies. Other in vitro studies have shown that several African traditional medicinal (ATM) plants and extracts may also demonstrate PK interactions with ARVs, through effects on CYP3A4, P-gp and PXR. The most complex effects were exhibited by Hypoxis hemerocallidea, Sutherlandia frutescens, Cyphostemma hildebrandtii, Acacia nilotica, Agauria salicifolia and Elaeodendron buchananii. Despite a high incidence of HIV/AIDs in the African region, only one clinical study, between efavirenz and Hypoxis hemerocallidea has been conducted. However, several issues/concerns still remain to be addressed and thus more studies on ATMs are warranted in order for more meaningful data to be generated and the true potential for such interactions to be determined. Copyright © 2011 John Wiley & Sons, Ltd.

  10. Pharmacokinetic drug-drug interaction between erlotinib and paracetamol: A potential risk for clinical practice.

    Science.gov (United States)

    Karbownik, Agnieszka; Szałek, Edyta; Sobańska, Katarzyna; Grabowski, Tomasz; Wolc, Anna; Grześkowiak, Edmund

    2017-05-01

    Erlotinib is a tyrosine kinase inhibitor available for the treatment of non-small cell lung cancer. Paracetamol is an analgesic agent, commonly used in cancer patients. Because these drugs are often co-administered, there is an increasing issue of interaction between them. The aim of the study was to investigate the effect of paracetamol on the pharmacokinetic parameters of erlotinib, as well as the influence of erlotinib on the pharmacokinetics of paracetamol. The rabbits were divided into three groups: the rabbits receiving erlotinib (I ER ), the group receiving paracetamol (II PR ), and the rabbits receiving erlotinib+paracetamol (III ER+PR ). A single dose of erlotinib was administered orally (25mg) and was administered intravenously (35mg/kg). Plasma concentrations of erlotinib, its metabolite (OSI420), paracetamol and its metabolites - glucuronide and sulphate were measured with the validated method. During paracetamol co-administration we observed increased erlotinib maximum concentration (C max ) and area under the plasma concentration-time curve from time zero to infinity (AUC 0-∞ ) by 87.7% and 31.1%, respectively. In turn, erlotinib lead to decreased paracetamol AUC 0-∞ by 35.5% and C max by 18.9%. The mean values of paracetamol glucuronide/paracetamol ratios for C max were 32.2% higher, whereas paracetamol sulphate/paracetamol ratios for C max and AUC 0-∞ were 37.1% and 57.1% lower in the II PR group, when compared to the III ER+PR group. Paracetamol had significant effect on the enhanced plasma exposure of erlotinib. Additionally, erlotinib contributed to the lower concentrations of paracetamol. Decreased glucuronidation and increased sulphation of paracetamol after co-administration of erlotinib were also observed. Copyright © 2017. Published by Elsevier B.V.

  11. Predicting drug?drug interactions through drug structural similarities and interaction networks incorporating pharmacokinetics and pharmacodynamics knowledge

    OpenAIRE

    Takeda, Takako; Hao, Ming; Cheng, Tiejun; Bryant, Stephen H.; Wang, Yanli

    2017-01-01

    Drug?drug interactions (DDIs) may lead to adverse effects and potentially result in drug withdrawal from the market. Predicting DDIs during drug development would help reduce development costs and time by rigorous evaluation of drug candidates. The primary mechanisms of DDIs are based on pharmacokinetics (PK) and pharmacodynamics (PD). This study examines the effects of 2D structural similarities of drugs on DDI prediction through interaction networks including both PD and PK knowledge. Our a...

  12. Herb-Drug Interaction between the Traditional Hepatoprotective Formulation and Sorafenib on Hepatotoxicity, Histopathology and Pharmacokinetics in Rats

    Directory of Open Access Journals (Sweden)

    Chin-Tsung Ting

    2017-06-01

    Full Text Available Sorafenib has been used as a standard therapy for advanced hepatocellular carcinoma (HCC. In Asia, patients with HCC are potentially treated with the combination of sorafenib and Chinese herbal medicines to improve the efficiency and reduce the side effects of sorafenib. However, limited information about the herb-drug interactions is available. We hypothesize that the Chinese herbal medicine may exert hepatoprotective effects on the sorafenib-treated group. The aim of this study is to investigate the pharmacokinetic mechanism of drug-drug interactions of sorafenib including interacting with hepatoprotective formulation, Long-Dan-Xie-Gan-Tang formulation (LDXGT and with two cytochrome P450 3A4 (CYP3A4 inhibitors, grapefruit juice and ketoconazole. Liver enzyme levels and histopathology of liver slices were used to evaluate sorafenib-induced hepatotoxicity and the potential hepatoprotective effects of the LDXGT formulation on subjects treated with the combination of sorafenib and the herbal medicine. In this study, a validated HPLC-photodiode array analytical system was developed for the pharmacokinetic study of sorafenib in rats. As the result of the pharmacokinetic data, pretreatment with the LDXGT formulation did not significantly interact with sorafenib compared with sorafenib oral administration alone. Furthermore, grapefruit juice and ketoconazole did not significantly affect sorafenib metabolism. Furthermore, pretreatment with variable, single or repeat doses of the LDXGT formulation did not suppress or exacerbate the sorafenib-induced hepatotoxicity and histopathological alterations. According to these results, the LDXGT formulation is safe, but has no beneficial effects on sorafenib-induced hepatotoxicity. A detailed clinical trial should be performed to further evaluate the efficacy or adverse effects of the LDXGT formulation in combination with sorafenib in humans.

  13. Bench to Bed Evidences for Pharmacokinetic and Pharmacodynamic Interactions Involving Oseltamivir and Chinese Medicine

    Directory of Open Access Journals (Sweden)

    Qi Chang

    2014-01-01

    Full Text Available Oseltamivir (OA, an ethyl ester prodrug of oseltamivir carboxylate (OC, is clinically used as a potent and selective inhibitor of neuraminidase. Chinese medicines have been advocated to combine with conventional drug for avian influenza. The current study aims to investigate the potential pharmacokinetic and pharmacodynamic interactions of a Chinese medicine formula, namely, Yin Qiao San and Sang Ju Yin (CMF1, commonly used for anti-influenza in combination with OA in both rat and human, and to reveal the underlined mechanisms. It was found that although Cmax, AUC and urinary recovery of OC, as well as metabolic ratio (AUCOC/AUCOA, were significantly decreased in a dose-dependent manner following combination use of CMF1 and OA in rat studies (P<0.01, such coadministration in 14 healthy volunteers only resulted in a trend of minor decrease in the related parameters. Further mechanistic studies found that although CMF1 could reduce absorption and metabolism of OA, it appears to enhance viral inhibition of OA (P<0.01. In summary, although there was potential interaction between OA and CMF1 found in rat studies, its clinical impact was expected to be minimal. The coadministration of OA and CMF1 at the clinical recommended dosages is, therefore, considered to be safe.

  14. In vivo pharmacodynamic and pharmacokinetic interactions of Hibiscus sabdariffa calyces extracts with simvastatin.

    Science.gov (United States)

    Showande, S J; Adegbolagun, O M; Igbinoba, S I; Fakeye, T O

    2017-12-01

    Increasing number of patients use herbs with their medications. Such practice may result in beneficial or harmful herb-drug interactions. A recent survey reported that some participants co-administered Hibiscus sabdariffa, a widely used beverage, or tea, with their antihyperlipidaemic medications. This study therefore evaluated the effect of concomitant administration of Hibiscus sabdariffa calyces' extracts with simvastatin on hyperlipidaemia and pharmacokinetics of the drug in vivo. Factorial experimental designs were used to evaluate the comparative effectiveness and interactions between simvastatin and aqueous extract of Hibiscus sabdariffa (AEHS) on lipid profile parameters in hyperlipidaemia-induced Wistar rats. Different combinations of low (AEHS 250 mg/kg; simvastatin 10 mg/kg) and high doses (AEHS 500 mg/kg; simvastatin 20 mg/kg) were administered individually and concurrently daily for 2 and 4 weeks. Lipid profile parameters were assessed at these treatment periods. Subsequently, the effect of aqueous beverage of Hibiscus sabdariffa (ABHS) on the pharmacokinetics of single-dose 40 mg simvastatin was also evaluated in six healthy human volunteers using two-period randomized crossover design. Blood samples were collected at predetermined times for 24 hours. The plasma obtained was analysed for simvastatin using RP-HPLC/UV method. Aqueous extract of Hibiscus sabdariffa reduced total cholesterol (T c ) better than simvastatin (P = .031). Low-dose AEHS and low-dose simvastatin used concomitantly caused 38.3% and 57.4% reductions in T c and triglyceride levels, respectively, compared with low-dose simvastatin (P Hibiscus sabdariffa lowered T c better than simvastatin and enhanced the antihyperlipidaemic activity of the drug when co-administered at low doses in an animal model. However, aqueous beverage of Hibiscus sabdariffa caused a significant herb-drug interaction resulting in overall reduction in exposure to simvastatin in humans. Caution should

  15. A review of pharmacokinetic drug-drug interactions with the anthelmintic medications albendazole and mebendazole.

    Science.gov (United States)

    Pawluk, Shane Ashley; Roels, Craig Allan; Wilby, Kyle John; Ensom, Mary H H

    2015-04-01

    Medications indicated for helminthes and other parasitic infections are frequently being used in mass populations in endemic areas. Currently, there is a lack of guidance for clinicians on how to appropriately manage drug interactions when faced with patients requiring short-term anthelmintic therapy with albendazole or mebendazole while concurrently taking other agents. The objective of this review was to systematically summarize and evaluate published literature on the pharmacokinetics of albendazole or mebendazole when taken with other interacting medications. A search of MEDLINE (1946 to October 2014), EMBASE (1974 to October 2014), International Pharmaceutical Abstracts (1970 to October 2014), Google, and Google Scholar was conducted for articles describing the pharmacokinetics of albendazole or mebendazole when given with other medications (and supplemented by a bibliographic review of all relevant articles). Altogether, 17 articles were included in the review. Studies reported data on pharmacokinetic parameters for albendazole or mebendazole when taken with cimetidine, dexamethasone, ritonavir, phenytoin, carbamazepine, phenobarbital, ivermectin, praziquantel, diethylcarbamazine, azithromycin, and levamisole. Cimetidine increased the elimination half-life of albendazole and maximum concentration (Cmax) of mebendazole; dexamethasone increased the area under the plasma concentration-time curve (AUC) of albendazole; levamisole decreased the Cmax of albendazole; anticonvulsants (phenytoin, phenobarbital, carbamazepine) decreased the AUC of albendazole; praziquantel increased the AUC of albendazole; and ritonavir decreased the AUC of both albendazole and mebendazole. No major interactions were found with ivermectin, azithromycin, or diethylcarbamazine. Future research is required to clarify the clinical relevance of the interactions observed.

  16. Pharmacokinetic drug-drug interaction and their implication in clinical management

    OpenAIRE

    Palleria, Caterina; DI PAOLO, Antonello; Giofrè, Chiara; Caglioti, Chiara; Leuzzi, Giacomo; Siniscalchi, Antonio; De Sarro, Giovambattista; Gallelli, Luca

    2013-01-01

    Drug-drug interactions (DDIs) are one of the commonest causes of medication error in developed countries, particularly in the elderly due to poly-therapy, with a prevalence of 20-40%. In particular, poly-therapy increases the complexity of therapeutic management and thereby the risk of clinically important DDIs, which can both induce the development of adverse drug reactions or reduce the clinical efficacy. DDIs can be classify into two main groups: pharmacokinetic and pharmacodynamic. In thi...

  17. Curcumin as a clinically-promising anti-cancer agent: pharmacokinetics and drug interactions.

    Science.gov (United States)

    Adiwidjaja, Jeffry; McLachlan, Andrew J; Boddy, Alan V

    2017-09-01

    Curcumin has been extensively studied for its anti-cancer properties. While a diverse array of in vitro and preclinical research support the prospect of curcumin use as an anti-cancer therapeutic, most human studies have failed to meet the intended clinical expectation. Poor systemic availability of orally-administered curcumin may account for this disparity. Areas covered: This descriptive review aims to concisely summarise available clinical studies investigating curcumin pharmacokinetics when administered in different formulations. A critical analysis of pharmacokinetic- and pharmacodynamic-based interactions of curcumin with concomitantly administered drugs is also provided. Expert opinion: The encouraging clinical results of curcumin administration are currently limited to people with colorectal cancer, given that sufficient curcumin concentrations persist in colonic mucosa. Higher parent curcumin systemic exposure, which can be achieved by several newer formulations, has important implications for optimal treatment of cancers other than those in gastrointestinal tract. Curcumin-drug pharmacokinetic interactions are also almost exclusively in the enterocytes, owing to extensive first pass metabolism and poor curcumin bioavailability. Greater scope of these interactions, i.e. modulation of the systemic elimination of co-administered drugs, may be expected from more-bioavailable curcumin formulations. Further studies are still warranted, especially with newer formulations to support the inclusion of curcumin in cancer therapy regimens.

  18. Interaction between Red Yeast Rice and CYP450 Enzymes/P-Glycoprotein and Its Implication for the Clinical Pharmacokinetics of Lovastatin

    Directory of Open Access Journals (Sweden)

    Chia-Hao Chen

    2012-01-01

    Full Text Available Red yeast rice (RYR can reduce cholesterol through its active component, lovastatin. This study was to investigate the pharmacokinetic properties of lovastatin in RYR products and potential RYR-drug interactions. Extracts of three registered RYR products (LipoCol Forte, Cholestin, and Xuezhikang were more effective than pure lovastatin in inhibiting the activities of cytochrome P450 enzymes and P-glycoprotein. Among CYP450 enzymes, RYR showed the highest inhibition on CYP1A2 and CYP2C19, with comparable inhibitory potencies to the corresponding typical inhibitors. In healthy volunteers taking the RYR product LipoCol Forte, the pharmacokinetic properties of lovastatin and lovastatin acid were linear in the dose range of 1 to 4 capsules taken as a single dose and no significant accumulation was observed after multiple dosing. Concomitant use of one LipoCol Forte capsule with nifedipine did not change the pharmacokinetics of nifedipine. Yet, concomitant use of gemfibrozil with LipoCol Forte resulted in a significant increase in the plasma concentration of lovastatin acid. These findings suggest that the use of RYR products may not have effects on the pharmacokinetics of concomitant comedications despite their effects to inhibit the activities of CYP450 enzymes and P-gp, whereas gemfibrozil affects the pharmacokinetics of lovastatin acid when used concomitantly with RYR products.

  19. Pharmacokinetic drug interaction between gemfibrozil and sitagliptin in healthy Indian male volunteers.

    Science.gov (United States)

    K P, Arun; Meda, Venkata Subbaiah; Kucherlapati, V S P Raj; Dubala, Anil; M, Deepalakshmi; P R, Anand VijayaKumar; K, Elango; B, Suresh

    2012-05-01

    To study the impact of gemfibrozil co-administration on the pharmacokinetics of sitagliptin in healthy Indian male volunteers. A randomized open label two-period crossover study involving 12 healthy Indian male volunteers was conducted at a single center. In each phase, the volunteers were administered sitagliptin as 100 mg tablets, either alone or co-administered with gemfibrozil as 600 mg tablets twice daily for 3 days. There was a 2-week washout period between phases. The venous blood samples were serially collected at 0-12 h post-dose, and plasma concentrations of the study drugs were estimated by a validated high-performance liquid chromatography-ultraviolet method. Relative to the administration of sitagliptin alone, co-administration with gemfibrozil increased the AUC₀₋₁₂ (2,167 ± 82.9 vs. 2,970 ± 76.4 ng h/ml; p gemfibrozil, this interaction may not have any clinical significance as sitagliptin has a wide therapeutic index. Hence, in clinical practice, sitagliptin as 100 mg tablets and gemfibrozil as 600 mg tablets may be co-prescribed without much threat of sitagliptin toxicity. However, these results may not hold if the dose of sitagliptin is increased or if is co-prescribed with other antidiabetic drugs and/or cytochrome P450 2C8/human organic anion transporter-3 inhibitors. Further studies are needed to confirm these results in patients.

  20. Nonlinear mixed effects modelling approach in investigating phenobarbital pharmacokinetic interactions in epileptic patients.

    Science.gov (United States)

    Vučićević, Katarina; Jovanović, Marija; Golubović, Bojana; Kovačević, Sandra Vezmar; Miljković, Branislava; Martinović, Žarko; Prostran, Milica

    2015-02-01

    The present study aimed to establish population pharmacokinetic model for phenobarbital (PB), examining and quantifying the magnitude of PB interactions with other antiepileptic drugs concomitantly used and to demonstrate its use for individualization of PB dosing regimen in adult epileptic patients. In total 205 PB concentrations were obtained during routine clinical monitoring of 136 adult epilepsy patients. PB steady state concentrations were measured by homogeneous enzyme immunoassay. Nonlinear mixed effects modelling (NONMEM) was applied for data analyses and evaluation of the final model. According to the final population model, significant determinant of apparent PB clearance (CL/F) was daily dose of concomitantly given valproic acid (VPA). Typical value of PB CL/F for final model was estimated at 0.314 l/h. Based on the final model, co-therapy with usual VPA dose of 1000 mg/day, resulted in PB CL/F average decrease of about 25 %, while 2000 mg/day leads to an average 50 % decrease in PB CL/F. Developed population PB model may be used in estimating individual CL/F for adult epileptic patients and could be applied for individualizing dosing regimen taking into account dose-dependent effect of concomitantly given VPA.

  1. Evaluation of the pharmacokinetic and pharmacodynamic drug interactions between cilnidipine and valsartan, in healthy volunteers

    Science.gov (United States)

    Lee, Jieon; Lee, Howard; Jang, Kyungho; Lim, Kyoung Soo; Shin, Dongseong; Yu, Kyung-Sang

    2014-01-01

    Purpose Although cilnidipine and valsartan are widely coadministered to patients with hypertension, their drug–drug interaction potential has not been investigated. This study compared the pharmacokinetic (PK), pharmacodynamic (PD), and tolerability profiles of cilnidipine and valsartan, both alone and in combination, in healthy male subjects. Patients and methods Fifty-four subjects, enrolled into an open-label, single-dose, three-treatment, three-period crossover study, randomly received cilnidipine (10 mg), valsartan (160 mg), or both according to one of six sequences. Blood samples were collected at baseline and up to 24 hours after drug administration in each period. Plasma concentrations of cilnidipine and valsartan were determined by liquid chromatography with tandem mass spectrometry. Maximum plasma concentration (Cmax) and area under the concentration-time curve from 0 to the last measurable time (AUClast) were estimated using a noncompartmental method. Tolerability was evaluated by assessing adverse events (AEs), vital signs, electrocardiograms, and clinical laboratory tests. Blood pressure was also measured for PD assessment. Results A total of 51 subjects completed the study. The PK profile of cilnidipine was not significantly affected by coadministered valsartan; the geometric mean ratio and 90% confidence interval (90% CI) of AUClast for cilnidipine with and without valsartan was 1.04 (0.98–1.10). Likewise, cilnidipine did not affect the PK of valsartan; the geometric mean ratio (90% CI) of AUClast for valsartan with and without cilnidipine was 0.94 (0.83–1.07). Coadministration of cilnidipine and valsartan reduced blood pressure in an additive way. No serious AEs were reported, and both cilnidipine and valsartan were well tolerated. Conclusion Coadministered cilnidipine and valsartan do not cause a significant PK or PD interaction, and they are well tolerated. PMID:25336921

  2. Pharmacokinetic drug-drug interaction and their implication in clinical management.

    Science.gov (United States)

    Palleria, Caterina; Di Paolo, Antonello; Giofrè, Chiara; Caglioti, Chiara; Leuzzi, Giacomo; Siniscalchi, Antonio; De Sarro, Giovambattista; Gallelli, Luca

    2013-07-01

    Drug-drug interactions (DDIs) are one of the commonest causes of medication error in developed countries, particularly in the elderly due to poly-therapy, with a prevalence of 20-40%. In particular, poly-therapy increases the complexity of therapeutic management and thereby the risk of clinically important DDIs, which can both induce the development of adverse drug reactions or reduce the clinical efficacy. DDIs can be classify into two main groups: pharmacokinetic and pharmacodynamic. In this review, using Medline, PubMed, Embase, Cochrane library and Reference lists we searched articles published until June 30 2012, and we described the mechanism of pharmacokinetic DDIs focusing the interest on their clinical implications.

  3. Pharmacokinetic drug-drug interaction and their implication in clinical management

    Directory of Open Access Journals (Sweden)

    Palleria Caterina

    2013-01-01

    Full Text Available Drug-drug interactions (DDIs are one of the commonest causes of medication error in developed countries, particularly in the elderly due to poly-therapy, with a prevalence of 20-40%. In particular, poly-therapy increases the complexity of therapeutic management and thereby the risk of clinically important DDIs, which can both induce the development of adverse drug reactions or reduce the clinical efficacy. DDIs can be classify into two main groups: pharmacokinetic and pharmacodynamic. In this review, using Medline, PubMed, Embase, Cochrane library and Reference lists we searched articles published until June 30 2012, and we described the mechanism of pharmacokinetic DDIs focusing the interest on their clinical implications.

  4. A systematic review of the pharmacokinetic and pharmacodynamic interactions of herbal medicine with warfarin.

    Directory of Open Access Journals (Sweden)

    Songie Choi

    Full Text Available The aim of this study was to systematically review data regarding pharmacokinetic (PK-pharmacodynamic (PD parameters from randomized controlled trials relating to interactions between herbal medicines and warfarin.Three electronic databases were searched to identify relevant trials. Two reviewers independently performed the study selection and data extraction. The risk of bias and reporting quality were also assessed independently by two reviewers using the Cochrane risk of bias tool and the consolidated standards of reporting trials (CONSORT. Outcomes were measured for all reported PK-PD parameters and adverse events.Nine randomized controlled trials met our inclusion criteria. Most of the included studies were unclear regarding the risk of bias and had a low quality of methodology. Using CONSORT, the reporting percentages for the articles ranged from 36.5% to 61.5% and the mean percentage for all articles was 45.6%. St John's wort and echinacea affected the PK parameters of warfarin. Ginseng, ginger, garlic, and cranberry had no significant effect on the PK parameters. American ginseng altered the PD parameters of warfarin. St John's wort, ginseng, Korea red ginseng, ginkgo, ginger, garlic, aged garlic, and echincea did not significantly alter the PD parameters. Studies of ginkgo and cranberry showed conflicting results on the PK parameters and PD parameters, respectively. The incidence of adverse events in all trials was low and no major adverse events were reported.It was difficult to determine whether ten herbal medicines had significant effects on the PK-PD parameters of warfarin. Low quality of evidence, different compounds within and different compositions of the herbs, and methodological limitations of the crossover study, which is a clinical study in which subjects receive a sequence of different interventions, made it difficult to form conclusions. Additional studies that remedy these vulnerabilities are necessary to verify these

  5. Pharmacokinetic interaction between udenafil and dapoxetine: a randomized, open-labeled crossover study in healthy male volunteers

    Directory of Open Access Journals (Sweden)

    Kim YH

    2015-02-01

    . Conclusion: Udenafil was found to have no clinically significant pharmacokinetic interactions with dapoxetine. The concurrent administration of udenafil and dapoxetine was generally well tolerated. Keywords: drug interaction, pharmacokinetics, erectile dysfunction, premature ejaculation

  6. Pharmacokinetic and pharmacodynamic interactions of morin and cyclosporin

    International Nuclear Information System (INIS)

    Fang, S.-H.; Hou, Y.-C.; Chao, P.-D.L.

    2005-01-01

    Morin is a flavonoid present in mulberry and herbs. We have reported that morin exerted anti-inflammatory activity on the activated macrophages. Cyclosporin (CsA) is a potent immunosuppressive agent with narrow therapeutic range, which is widely used for the treatments of autoimmune diseases and transplantation rejection. This study aimed to measure the effects of morin on the disposition of CsA in lymphoid and non-lymphoid tissues, and on the functions of immune cells in mice. CsA (Neoral, 10 mg/kg) was orally administered with and without a concomitant dose of morin (0, 50, 100, 200 mg/kg) to mice once daily for 2 weeks. CsA concentrations in blood, liver, kidney, and spleen were determined by a specific monoclonal fluorescence polarization immunoassay. The decreased levels of CsA in tissues were found well correlated to increased doses of morin. The coadministration of 200 mg/kg morin significantly decreased CsA in blood, liver, kidney, and spleen by 33%, 17%, 38%, and 45%, respectively. On the other hand, coadministration of morin decreased dramatically the nitric oxide production by the activated macrophages when compared to CsA treatment alone. Moreover, morin maintained the level of CsA-suppressed T helper 1 (Th1) type cytokine, although the CsA concentration in spleen was markedly reduced. In conclusion, morin coadministration profoundly reduced CsA concentration but did not significantly alter the CsA-suppressed Th1 immune response in mice

  7. Evaluating Pharmacokinetic and Pharmacodynamic Interactions with Computational Models in Supporting Cumulative Risk Assessment

    Science.gov (United States)

    Tan, Yu-Mei; Clewell, Harvey; Campbell, Jerry; Andersen, Melvin

    2011-01-01

    Simultaneous or sequential exposure to multiple chemicals may cause interactions in the pharmacokinetics (PK) and/or pharmacodynamics (PD) of the individual chemicals. Such interactions can cause modification of the internal or target dose/response of one chemical in the mixture by other chemical(s), resulting in a change in the toxicity from that predicted from the summation of the effects of the single chemicals using dose additivity. In such cases, conducting quantitative cumulative risk assessment for chemicals present as a mixture is difficult. The uncertainties that arise from PK interactions can be addressed by developing physiologically based pharmacokinetic (PBPK) models to describe the disposition of chemical mixtures. Further, PK models can be developed to describe mechanisms of action and tissue responses. In this article, PBPK/PD modeling efforts conducted to investigate chemical interactions at the PK and PD levels are reviewed to demonstrate the use of this predictive modeling framework in assessing health risks associated with exposures to complex chemical mixtures. PMID:21655141

  8. Pharmacokinetic and pharmacodynamic interaction for a binary mixture of chlorpyrifos and diazinon in the rat

    International Nuclear Information System (INIS)

    Timchalk, C.; Poet, T.S.; Hinman, M.N.; Busby, A.L.; Kousba, A.A.

    2005-01-01

    Chlorpyrifos (CPF) and diazinon (DZN) are two commonly used organophosphorus (OP) insecticides and a potential exists for concurrent exposures. The primary neurotoxic effects from OP pesticide exposures result from the inhibition of acetylcholinesterase (AChE). The pharmacokinetic and pharmacodynamic impact of acute binary exposures of rats to CPF and DZN was evaluated in this study. Rats were orally administered CPF, DZN, or a CPF/DZN mixture (0, 15, 30, or 60 mg/kg) and blood (plasma and RBC), and brain were collected at 0, 3, 6, 12, and 24 h postdosing, urine was also collected at 24 h. Chlorpyrifos, DZN, and their respective metabolites, 3,5,6-trichloro-2-pyridinol (TCP) and 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMHP), were quantified in blood and/or urine and cholinesterase (ChE) inhibition was measured in brain, RBC, and plasma. Coexposure to CPF/DZN at the low dose of 15/15 mg/kg did not alter the pharmacokinetics of CPF, DZN, or their metabolites in blood. A high binary dose of 60/60 mg/kg increased the C max and AUC and decreased the clearance for both parent compounds, likely due to competition between CPF and DZN for CYP450 metabolism. At lower doses, most likely to be encountered in occupational or environmental exposures, the pharmacokinetics were linear. A dose-dependent inhibition of ChE was noted in tissues for both the single and coexposures, and the extent of inhibition was plasma > RBC ≥ brain. The overall relative potency for ChE inhibition was CPF/DZN > CPF > DZN. A comparison of the ChE response at the low binary dose (15/15 mg/kg), where there were no apparent pharmacokinetic interactions, suggested that the overall ChE response was additive. These experiments represent important data concerning the potential pharmacokinetic and pharmacodynamic interactions for pesticide mixtures and will provide needed insight for assessing the potential cumulative risk associated with occupational or environmental exposures to these insecticides

  9. Pharmacokinetic drug interactions of morphine, codeine, and their derivatives: theory and clinical reality, part I.

    Science.gov (United States)

    Armstrong, Scott C; Cozza, Kelly L

    2003-01-01

    Pharmacokinetic drug-drug interactions with morphine, hydromorphone, and oxymorphone are reviewed in this column. Morphine is a naturally occurring opiate that is metabolized chiefly through glucuronidation by uridine diphosphate glucuronosyl transferase (UGT) enzymes in the liver. These enzymes produce an active analgesic metabolite and a potentially toxic metabolite. In vivo drug-drug interaction studies with morphine are few, but they do suggest that inhibition or induction of UGT enzymes could alter morphine and its metabolite levels. These interactions could change analgesic efficacy. Hydromorphone and oxymorphone, close synthetic derivatives of morphine, are also metabolized primarily by UGT enzymes. Hydromorphone may have a toxic metabolite similar to morphine. In vivo drug-drug interaction studies with hydromorphone and oxymorphone have not been done, so it is difficult to make conclusions with these drugs.

  10. Rifampicin and anti-hypertensive drugs in chronic kidney disease: Pharmacokinetic interactions and their clinical impact

    Directory of Open Access Journals (Sweden)

    A Agrawal

    2016-01-01

    Full Text Available Patients on dialysis have an increased incidence of tuberculosis (TB. Rifampicin, a first-line antitubercular therapy (ATT drug, is a potent inducer of hepatic cytochrome P450 (CYP. There is potential for pharmacokinetic interaction between rifampicin and anti-hypertensives that are CYP substrates: amlodipine and metoprolol. Therefore, hypertensive patients receiving rifampicin-based ATT are at risk for worsening of hypertension. However, this hypothesis has not yet been systematically studied. In this prospective study, hypertensive CKD 5D patients with TB were followed after rifampicin initiation. Blood pressure (BP was ≤140/90 mmHg with stable anti-HT requirement at inclusion. Serum amlodipine, metoprolol, and prazosin levels were estimated by high-performance liquid chromatography at baseline and 3, 7, 10, and 14 days after rifampicin initiation. BP and anti-HT requirement were monitored for 2 weeks or until stabilization. All 24 patients in the study had worsening of hypertension after rifampicin and 83.3% required increase in drugs to maintain BP 50% in all patients and became undetectable in 50-75%. Drug requirement increased from 4.5 ± 3.6 to 8.5 ± 6.4 units (P < 0.0001. Mean time to first increase in dose was 6.5 ± 3.6 days. Eleven (46% patients experienced a hypertensive crisis at 9.1 ± 3.8 days. Three of them had a hypertensive emergency with acute pulmonary edema. In two patients, rifampicin had to be discontinued to achieve BP control. In conclusion, rifampicin caused a significant decrease in blood levels of commonly used anti hypertensives. This decrease in levels correlated well with worsening of hypertension. Thus, we suggest very close BP monitoring in CKD patients after rifampicin initiation.

  11. Pharmacokinetic drug interactions of morphine, codeine, and their derivatives: theory and clinical reality, Part II.

    Science.gov (United States)

    Armstrong, Scott C; Cozza, Kelly L

    2003-01-01

    Pharmacokinetic drug-drug interactions with codeine, dihydrocodeine, hydrocodone, oxycodone, and buprenorphine are reviewed in this column. These compounds have a very similar chemical structure to morphine. Unlike morphine, which is metabolized chiefly through conjugation reactions with uridine diphosphate glucuronosyl transferase (UGT) enzymes, these five drugs are metabolized both through oxidative reactions by the cytochrome P450 (CYP450) enzyme and conjugation by UGT enzymes. There is controversy as to whether codeine, dihydrocodeine, and hydrocodone are actually prodrugs requiring activation by the CYP450 2D6 enzyme or UGT enzymes. Oxycodone and buprenorphine, however, are clearly not prodrugs and are metabolized by the CYP450 2D6 and 3A4 enzymes, respectively. Knowledge of this metabolism assists in the understanding for the potential of drug-drug interactions with these drugs. This understanding is important so that clinicians can choose the proper dosages for analgesia and anticipate potential drug-drug interactions.

  12. Herb-drug interaction of Andrographis paniculata (Nees) extract and andrographolide on pharmacokinetic and pharmacodynamic of naproxen in rats.

    Science.gov (United States)

    Balap, Aishwarya; Lohidasan, Sathiyanarayanan; Sinnathambi, Arulmozhi; Mahadik, Kakasaheb

    2017-01-04

    Andrographis paniculata Nees (Acanthacae) have broad range of pharmacological effects such as hepatoprotective, antifertility, antimalarial, antidiabetic, suppression of various cancer cells and anti-inflammatory properties and is widely used medicinal plant in the traditional Unani and Ayurvedic medicinal systems. Andrographolide (AN) is one of the active constituent of the A. paniculata Nees extract (APE). They have been found in many traditional herbal formulations in India and proven to be effective as anti-inflammatory drug. To evaluate the pharmacokinetic and pharmacodynamic (anti arthritic) herb-drug interactions of A. paniculata Nees extract (APE) and pure andrographolide (AN) with naproxen (NP) after oral co-administration in wistar rats. After oral co-administration of APE (200mg/Kg) and AN (60mg/kg) with NP (7.5mg/kg) in rats, drug concentrations in plasma were determined using HPLC method. The main pharmacokinetic parameters of C max , t max , t 1/2 , MRT, Vd, CL, and AUC were calculated by non-compartment model. Change in paw volume, mechanical nociceptive threshold, mechanical hyperalgesia, histopathology and hematological parameters were evaluated to study antiarthritic activity. Co-administration of NP with APE and pure AN decreased systemic exposure level of NP in vivo. The C max , t max, AUC 0-t of NP was decreased. In pharmacodynamic study, NP (10mg/kg) alone and NP+AN (10+60mg/kg) groups exhibited significant synergistic anti-arthritic activity as compared to groups NP+APE, APE and AN alone. The results obtained from this study suggested that NP, APE and pure AN existed pharmacokinetic herb-drug interactions in rat which is correlated with anti-arthritic study. The knowledge regarding possible herb-drug interaction of NP might be helpful for physicians as well as patients using AP. So further studies should be done to understand the effect of other herbal ingredients of APE on NP as well as to predict the herb-drug interaction in humans

  13. In Vitro Adsorption and in Vivo Pharmacokinetic Interaction between Doxycycline and Frequently Used Mycotoxin Binders in Broiler Chickens.

    Science.gov (United States)

    De Mil, Thomas; Devreese, Mathias; Broekaert, Nathan; Fraeyman, Sophie; De Backer, Patrick; Croubels, Siska

    2015-05-06

    Mycotoxin binders are readily mixed in feeds to prevent uptake of mycotoxins by the animal. Concerns were raised for nonspecific binding with orally administered veterinary drugs by the European Food Safety Authority in 2010. This paper describes the screening for in vitro adsorption of doxycycline-a broad-spectrum tetracycline antibiotic-to six different binders that were able to bind >75% of the doxycycline. Next, an in vivo pharmacokinetic interaction study of doxycycline with two of the binders, which demonstrated significant in vitro binding, was performed in broiler chickens using an oral bolus model. It was shown that two montmorillonite-based binders were able to lower the area under the plasma concentration-time curve of doxycycline by >60% compared to the control group. These results may indicate a possible risk for reduced efficacy of doxycycline when used concomitantly with montmorillonite-based mycotoxin binders.

  14. Identification of clinically significant drug-drug interactions in cardiac ...

    African Journals Online (AJOL)

    Purpose: To identify clinically significant potential drug-drug interactions in cardiac intensive care units of two tertiary care ... hypertension, hyperlipidemia, diabetes or other diseases .... May result in digoxin toxicity (nausea, vomiting, cardiac.

  15. Pharmacokinetic interactions between glimepiride and rosuvastatin in healthy Korean subjects: does the SLCO1B1 or CYP2C9 genetic polymorphism affect these drug interactions?

    Directory of Open Access Journals (Sweden)

    Kim CO

    2017-02-01

    Full Text Available Choon Ok Kim,1 Eun Sil Oh,2 Hohyun Kim,3 Min Soo Park1,4 1Department of Clinical Pharmacology, Severance Hospital, Yonsei University College of Medicine, Seoul, 2Department of Pharmaceutical Medicine and Regulatory Sciences, College of Medicine and Pharmacy, Yonsei University, Incheon, 3Korea Medicine Research Institute, Inc., Seongnam, 4Department of Pediatrics, Yonsei University College of Medicine, Seoul, Korea Abstract: To improve cardiovascular outcomes, dyslipidemia in patients with diabetes needs to be treated. Thus, these patients are likely to take glimepiride and rosuvastatin concomitantly. Therefore, this study aimed to evaluate the pharmacokinetic (PK interactions between these two drugs in healthy males and to explore the effect of SLCO1B1 and CYP2C9 polymorphisms on their interactions in two randomized, open-label crossover studies. Glimepiride was studied in part 1 and rosuvastatin in part 2. Twenty-four participants were randomly assigned to each part. All subjects (n=24 completed part 1, and 22 subjects completed part 2. A total of 38 subjects among the participants of the PK interaction studies were enrolled in the genotype study to analyze their SLCO1B1 and CYP2C9 polymorphisms retrospectively (n=22 in part 1, n=16 in part 2. Comparison of the PK and safety of each drug alone with those of the drugs in combination showed that both glimepiride and rosuvastatin did not interact with each other and had tolerable safety profiles in all subjects. However, with regard to glimepiride PK, the SLCO1B1 521TC group had a significantly higher maximum plasma concentration (Cmax,ss and area under the plasma concentration–time curve during the dose interval at steady state (AUCt,ss for glimepiride in combination with rosuvastatin than those for glimepiride alone. However, other significant effects of the SLCO1B1 or CYP2C9 polymorphism on the interaction between the two drugs were not observed. In conclusion, there were no significant PK

  16. Pharmacokinetic study of flunixin and its interaction with enrofloxacin after intramuscular administration in calves

    Directory of Open Access Journals (Sweden)

    K. Abo-EL-Sooud

    Full Text Available The Pharmacokinetic aspects of flunixin (FL administered alone and in combination with enrofloxacin (EN, were studied in clinically healthy calves. The experiments were performed on two groups: FL alone {2.2 mg/kg,intramuscular (IM}, and combination of FL (2.2 mg/kg, IM and EN {2.5 mg/kg, IM}. Plasma concentrations of FL were determined using High Performance Liquid Chromatography (HPLC method. Moreover, the effects of FL alone or in combination on liver and kidney functions were also assessed. Flunixin was rapidly absorbed intramuscularly with a half-life of absorption (t of 0.094 h and the peak plasma concentration (C was 1.27 g/mL was attained after 1/2ab max 0.49 h (T . Enrofloxacin significantly altered the pharmacokinetics of FL by delaying its absorption and accelerate its max elimination from body. Significant increases (32% in the area under the curve (AUC and (37% in the elimination rate constant (K from the central compartment and a significant decrease (27% in the elimination half-life (t of FL el 1/2el were found following coadministration with EN, compared with administration of FL alone. The maximum plasma drug concentration (C showed significant increase (28% following the coadministration of EN with FL as max compared to that following the administration of FL alone. It was concluded that the combination of FL and EN negatively altered the kinetics of FL and exaggerated the adverse effect on hepato-renal function in calves consequently; the concomitant use of FL and EN should be avoided in calves. [Vet. World 2011; 4(10.000: 449-454

  17. Application of physiologically based pharmacokinetic modeling in predicting drug–drug interactions for sarpogrelate hydrochloride in humans

    Directory of Open Access Journals (Sweden)

    Min JS

    2016-09-01

    Full Text Available Jee Sun Min,1 Doyun Kim,1 Jung Bae Park,1 Hyunjin Heo,1 Soo Hyeon Bae,2 Jae Hong Seo,1 Euichaul Oh,1 Soo Kyung Bae1 1Integrated Research Institute of Pharmaceutical Sciences, College of Pharmacy, The Catholic University of Korea, Bucheon, 2Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seocho-gu, Seoul, South Korea Background: Evaluating the potential risk of metabolic drug–drug interactions (DDIs is clinically important. Objective: To develop a physiologically based pharmacokinetic (PBPK model for sarpogrelate hydrochloride and its active metabolite, (R,S-1-{2-[2-(3-methoxyphenylethyl]-phenoxy}-3-(dimethylamino-2-propanol (M-1, in order to predict DDIs between sarpogrelate and the clinically relevant cytochrome P450 (CYP 2D6 substrates, metoprolol, desipramine, dextromethorphan, imipramine, and tolterodine. Methods: The PBPK model was developed, incorporating the physicochemical and pharmacokinetic properties of sarpogrelate hydrochloride, and M-1 based on the findings from in vitro and in vivo studies. Subsequently, the model was verified by comparing the predicted concentration-time profiles and pharmacokinetic parameters of sarpogrelate and M-1 to the observed clinical data. Finally, the verified model was used to simulate clinical DDIs between sarpogrelate hydrochloride and sensitive CYP2D6 substrates. The predictive performance of the model was assessed by comparing predicted results to observed data after coadministering sarpogrelate hydrochloride and metoprolol. Results: The developed PBPK model accurately predicted sarpogrelate and M-1 plasma concentration profiles after single or multiple doses of sarpogrelate hydrochloride. The simulated ratios of area under the curve and maximum plasma concentration of metoprolol in the presence of sarpogrelate hydrochloride to baseline were in good agreement with the observed ratios. The predicted fold-increases in the area under the curve ratios of metoprolol

  18. The interactional significance of formulas in autistic language.

    Science.gov (United States)

    Dobbinson, Sushie; Perkins, Mick; Boucher, Jill

    2003-01-01

    The phenomenon of echolalia in autistic language is well documented. Whilst much early research dismissed echolalia as merely an indicator of cognitive limitation, later work identified particular discourse functions of echolalic utterances. The work reported here extends the study of the interactional significance of echolalia to formulaic utterances. Audio and video recordings of conversations between the first author and two research participants were transcribed and analysed according to a Conversation Analysis framework and a multi-layered linguistic framework. Formulaic language was found to have predictable interactional significance within the language of an individual with autism, and the generic phenomenon of formulaicity in company with predictable discourse function was seen to hold across the research participants, regardless of cognitive ability. The implications of formulaicity in autistic language for acquisition and processing mechanisms are discussed.

  19. Structural mode significance using INCA. [Interactive Controls Analysis computer program

    Science.gov (United States)

    Bauer, Frank H.; Downing, John P.; Thorpe, Christopher J.

    1990-01-01

    Structural finite element models are often too large to be used in the design and analysis of control systems. Model reduction techniques must be applied to reduce the structural model to manageable size. In the past, engineers either performed the model order reduction by hand or used distinct computer programs to retrieve the data, to perform the significance analysis and to reduce the order of the model. To expedite this process, the latest version of INCA has been expanded to include an interactive graphical structural mode significance and model order reduction capability.

  20. Pharmacokinetic drug interactions with clopidogrel: updated review and risk management in combination therapy

    Directory of Open Access Journals (Sweden)

    Wang ZY

    2015-03-01

    Full Text Available Zhi-Yu Wang,1 Meng Chen,1 Ling-Ling Zhu,2 Lu-Shan Yu,3 Su Zeng,3 Mei-Xiang Xiang,4 Quan Zhou1 1Department of Pharmacy, 2VIP Care Ward, Division of Nursing, the Second Affiliated Hospital, School of Medicine, 3Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, 4Department of Cardiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, People’s Republic of China Background: Coprescribing of clopidogrel and other drugs is common. Available reviews have addressed the drug–drug interactions (DDIs when clopidogrel is as an object drug, or focused on combination use of clopidogrel and a special class of drugs. Clinicians may still be ignorant of those DDIs when clopidogrel is a precipitant drug, the factors determining the degree of DDIs, and corresponding risk management.Methods: A literature search was performed using PubMed, MEDLINE, Web of Science, and the Cochrane Library to analyze the pharmacokinetic DDIs of clopidogrel and new P2Y12 receptor inhibitors.Results: Clopidogrel affects the pharmacokinetics of cerivastatin, repaglinide, ferulic acid, sibutramine, efavirenz, and omeprazole. Low efficacy of clopidogrel is anticipated in the presence of omeprazole, esomeprazole, morphine, grapefruit juice, scutellarin, fluoxetine, azole antifungals, calcium channel blockers, sulfonylureas, and ritonavir. Augmented antiplatelet effects are anticipated when clopidogrel is coprescribed with aspirin, curcumin, cyclosporin, St John’s wort, rifampicin, and angiotensin-converting enzyme inhibitors. The factors determining the degree of DDIs with clopidogrel include genetic status (eg, cytochrome P540 [CYP]2B6*6, CYP2C19 polymorphism, CYP3A5*3, CYP3A4*1G, and CYP1A2-163C>A, species differences, and dose strength. The DDI risk does not exhibit a class effect, eg, the effects of clopidogrel on cerivastatin versus other statins, the effects of proton pump

  1. Venetoclax (ABT-199 Might Act as a Perpetrator in Pharmacokinetic Drug–Drug Interactions

    Directory of Open Access Journals (Sweden)

    Johanna Weiss

    2016-02-01

    Full Text Available Venetoclax (ABT-199 represents a specific B-cell lymphoma 2 (Bcl-2 inhibitor that is currently under development for the treatment of lymphoid malignancies. So far, there is no published information on its interaction potential with important drug metabolizing enzymes and drug transporters, or its efficacy in multidrug resistant (MDR cells. We therefore scrutinized its drug–drug interaction potential in vitro. Inhibition of cytochrome P450 enzymes (CYPs was quantified by commercial kits. Inhibition of drug transporters (P-glycoprotein (P-gp, ABCB1, breast cancer resistance protein (BCRP, and organic anion transporting polypeptides (OATPs was evaluated by the use of fluorescent probe substrates. Induction of drug transporters and drug metabolizing enzymes was quantified by real-time RT-PCR. The efficacy of venetoclax in MDR cells lines was evaluated with proliferation assays. Venetoclax moderately inhibited P-gp, BCRP, OATP1B1, OATP1B3, CYP3A4, and CYP2C19, whereas CYP2B6 activity was increased. Venetoclax induced the mRNA expression of CYP1A1, CYP1A2, UGT1A3, and UGT1A9. In contrast, expression of ABCB1 was suppressed, which might revert tumor resistance towards antineoplastic P-gp substrates. P-gp over-expression led to reduced antiproliferative effects of venetoclax. Effective concentrations for inhibition and induction lay in the range of maximum plasma concentrations of venetoclax, indicating that it might act as a perpetrator drug in pharmacokinetic drug–drug interactions.

  2. Venetoclax (ABT-199) Might Act as a Perpetrator in Pharmacokinetic Drug–Drug Interactions

    Science.gov (United States)

    Weiss, Johanna; Gajek, Thomas; Köhler, Bruno Christian; Haefeli, Walter Emil

    2016-01-01

    Venetoclax (ABT-199) represents a specific B-cell lymphoma 2 (Bcl-2) inhibitor that is currently under development for the treatment of lymphoid malignancies. So far, there is no published information on its interaction potential with important drug metabolizing enzymes and drug transporters, or its efficacy in multidrug resistant (MDR) cells. We therefore scrutinized its drug–drug interaction potential in vitro. Inhibition of cytochrome P450 enzymes (CYPs) was quantified by commercial kits. Inhibition of drug transporters (P-glycoprotein (P-gp, ABCB1), breast cancer resistance protein (BCRP), and organic anion transporting polypeptides (OATPs)) was evaluated by the use of fluorescent probe substrates. Induction of drug transporters and drug metabolizing enzymes was quantified by real-time RT-PCR. The efficacy of venetoclax in MDR cells lines was evaluated with proliferation assays. Venetoclax moderately inhibited P-gp, BCRP, OATP1B1, OATP1B3, CYP3A4, and CYP2C19, whereas CYP2B6 activity was increased. Venetoclax induced the mRNA expression of CYP1A1, CYP1A2, UGT1A3, and UGT1A9. In contrast, expression of ABCB1 was suppressed, which might revert tumor resistance towards antineoplastic P-gp substrates. P-gp over-expression led to reduced antiproliferative effects of venetoclax. Effective concentrations for inhibition and induction lay in the range of maximum plasma concentrations of venetoclax, indicating that it might act as a perpetrator drug in pharmacokinetic drug–drug interactions. PMID:26927160

  3. Venetoclax (ABT-199) Might Act as a Perpetrator in Pharmacokinetic Drug-Drug Interactions.

    Science.gov (United States)

    Weiss, Johanna; Gajek, Thomas; Köhler, Bruno Christian; Haefeli, Walter Emil

    2016-02-24

    Venetoclax (ABT-199) represents a specific B-cell lymphoma 2 (Bcl-2) inhibitor that is currently under development for the treatment of lymphoid malignancies. So far, there is no published information on its interaction potential with important drug metabolizing enzymes and drug transporters, or its efficacy in multidrug resistant (MDR) cells. We therefore scrutinized its drug-drug interaction potential in vitro. Inhibition of cytochrome P450 enzymes (CYPs) was quantified by commercial kits. Inhibition of drug transporters (P-glycoprotein (P-gp, ABCB1), breast cancer resistance protein (BCRP), and organic anion transporting polypeptides (OATPs)) was evaluated by the use of fluorescent probe substrates. Induction of drug transporters and drug metabolizing enzymes was quantified by real-time RT-PCR. The efficacy of venetoclax in MDR cells lines was evaluated with proliferation assays. Venetoclax moderately inhibited P-gp, BCRP, OATP1B1, OATP1B3, CYP3A4, and CYP2C19, whereas CYP2B6 activity was increased. Venetoclax induced the mRNA expression of CYP1A1, CYP1A2, UGT1A3, and UGT1A9. In contrast, expression of ABCB1 was suppressed, which might revert tumor resistance towards antineoplastic P-gp substrates. P-gp over-expression led to reduced antiproliferative effects of venetoclax. Effective concentrations for inhibition and induction lay in the range of maximum plasma concentrations of venetoclax, indicating that it might act as a perpetrator drug in pharmacokinetic drug-drug interactions.

  4. Interaction study of aspirin or clopidogrel on pharmacokinetics of donepezil hydrochloride in rats by HPLC-fluorescence detection.

    Science.gov (United States)

    Wada, Mitsuhiro; Nishiwaki, Junichiro; Yamane, Tomoko; Ohwaki, Yuichi; Aboul-Enein, Hassan Y; Nakashima, Kenichiro

    2007-06-01

    The present study aims to investigate the possibility of interaction of aspirin (Asp) or clopidogrel (CG) on donepezil (DP) hydrochloride in rats by HPLC-fluorescence detection. The separation of DP was achieved in ca. 13 min without interference of Asp and CG on the chromatogram. DP levels in rat plasma with a single administration of DP (5 mg/kg, i.p., group I) and those with a co-administration of Asp (200 mg/kg, p.o., group II or 200 mg/kg, i.p., group III) or CG (5 mg/kg, p.o., group IV) were monitored. The DP concentrations determined in rat plasma ranged from 25.0 to 336.1 ng/mL. Pharmacokinetic parameters for these groups were calculated and compared with one another. No significant difference was observed on the comparison of group I with other groups except for the mean resident time of group IV (p = 0.012). These basic findings may help clinical inference when DP is co-administered with Asp and CG to human. Copyright 2007 John Wiley & Sons, Ltd.

  5. Using Nonexperts for Annotating Pharmacokinetic Drug-Drug Interaction Mentions in Product Labeling: A Feasibility Study.

    Science.gov (United States)

    Hochheiser, Harry; Ning, Yifan; Hernandez, Andres; Horn, John R; Jacobson, Rebecca; Boyce, Richard D

    2016-04-11

    Because vital details of potential pharmacokinetic drug-drug interactions are often described in free-text structured product labels, manual curation is a necessary but expensive step in the development of electronic drug-drug interaction information resources. The use of nonexperts to annotate potential drug-drug interaction (PDDI) mentions in drug product label annotation may be a means of lessening the burden of manual curation. Our goal was to explore the practicality of using nonexpert participants to annotate drug-drug interaction descriptions from structured product labels. By presenting annotation tasks to both pharmacy experts and relatively naïve participants, we hoped to demonstrate the feasibility of using nonexpert annotators for drug-drug information annotation. We were also interested in exploring whether and to what extent natural language processing (NLP) preannotation helped improve task completion time, accuracy, and subjective satisfaction. Two experts and 4 nonexperts were asked to annotate 208 structured product label sections under 4 conditions completed sequentially: (1) no NLP assistance, (2) preannotation of drug mentions, (3) preannotation of drug mentions and PDDIs, and (4) a repeat of the no-annotation condition. Results were evaluated within the 2 groups and relative to an existing gold standard. Participants were asked to provide reports on the time required to complete tasks and their perceptions of task difficulty. One of the experts and 3 of the nonexperts completed all tasks. Annotation results from the nonexpert group were relatively strong in every scenario and better than the performance of the NLP pipeline. The expert and 2 of the nonexperts were able to complete most tasks in less than 3 hours. Usability perceptions were generally positive (3.67 for expert, mean of 3.33 for nonexperts). The results suggest that nonexpert annotation might be a feasible option for comprehensive labeling of annotated PDDIs across a broader

  6. Diclofenac sex-divergent drug-drug interaction with Sunitinib: pharmacokinetics and tissue distribution in male and female mice.

    Science.gov (United States)

    Chew, Chii Chii; Ng, Salby; Chee, Yun Lee; Koo, Teng Wai; Liew, Ming Hui; Chee, Evelyn Li-Ching; Modamio, Pilar; Fernández, Cecilia; Mariño, Eduardo L; Segarra, Ignacio

    2017-08-01

    Coadministration of diclofenac and sunitinib, tyrosine kinase inhibitor, led to sex-divergent pharmacokinetic drug-drug interaction outcomes. Male and female mice were administered 60 mg/kg PO sunitinib alone (control groups) or with 30 mg/kg PO diclofenac. Sunitinib concentration in plasma, brain, kidney and liver were determined by HPLC and non-compartmental pharmacokinetic parameters calculated. In male mice, diclofenac decreased AUC 0→∞ 38% in plasma (p diclofenac increased the liver uptake efficiency in male (27%, p diclofenac with probable clinical translatability due to potential different effects in male and female patients requiring careful selection of the NSAID and advanced TDM to implement a personalized treatment.

  7. Pharmacokinetic Interactions between the Hormonal Emergency Contraception, Levonorgestrel (Plan B, and Efavirenz

    Directory of Open Access Journals (Sweden)

    Monica L. Carten

    2012-01-01

    Full Text Available Objectives. Compare the Plan B levonorgestrel (LNG area under the concentration- time curve (AUC12 prior to and with efavirenz (EFV. Design. Prospective, open-label, single-arm, equivalence study. Methods. Healthy HIV-negative subjects underwent 12 hr intensive pharmacokinetic (PK sampling following single dose LNG alone and after 14 days of EFV. Geometric means, Geometric Mean Ratios, and 90% confidence intervals (CI are reported for PK Parameters. T-tests were utilized. Clinical parameters and liver function tests (LFTs were assessed. Results. 24 women enrolled and 21 completed the study. With EFV, LNG AUC12 was reduced 56% (95% CI: 49%, 62% from 42.9 to 17.8 ng*hr/mL, and maximum concentration (Cmax⁡ was reduced 41% (95% CI: 33%, 50% from 8.4 to 4.6 ng/mL. LNG was well tolerated with no grade 3 or 4 treatment-related toxicities. Conclusions. EFV significantly reduced LNG exposures. Higher LNG doses may be required with EFV. These results reinforce the importance of effective contraception in women taking EFV.

  8. Efficacy of pharmacokinetic interactions between piperonyl butoxide and albendazole against gastrointestinal nematodiasis in goats.

    Science.gov (United States)

    Kumbhakar, N K; Sanyal, P K; Rawte, D; Kumar, D; Kerketta, A E; Pal, S

    2016-09-01

    To test the hypothesis that modulation of hepatic microsomal sulphoxidation and sulphonation by the cytochrome P450 inhibitor piperonyl butoxide could increase bioavailability of albendazole, the present study was undertaken to understand the pharmacokinetics of albendazole in goats at a dose of 7.5 mg kg- 1 body weight with and without co-administration with piperonyl butoxide at 63.0 mg kg- 1 body weight. Plasma albendazole sulphoxide metabolite, the anthelmintically active moiety, reached its maximum concentration of 0.322 ± 0.045 μg ml- 1 and 0.384 ± 0.013 μg ml- 1 at 18 h and 24 h after administration of albendazole alone and co-administration of albendazole with piperonyl butoxide, respectively. Analysis of the data revealed statistically increased albendazole sulphoxide levels at 24 (P 0.05) in values of maximum concentration (normal and calculated) could be observed between groups of goats. However, values of time to reach the concentration maximum (normal and calculated), area under the concentration-time curve (0-∞ and calculated), minimum residence time, distribution half-life, elimination half-life and total area under the first movement of plasma drug concentration-time curve were significantly higher (P albendazole sulphoxide in goats following single oral co-administration of albendazole with piperonyl butoxide. The faecal egg count reduction and lower 95% confidence limit for the group treated with albendazole alone were 97 and 68%, while for co-administration of albendazole and piperonyl butoxide the values were 99 and 97%, respectively. The ED50 for egg hatch was 0.196, indicating suspected resistance to benzimidazole anthelmintics. The drug combination proved efficacious against an albendazole-resistant nematode parasite population in goats.

  9. Pharmacokinetic Drug-Drug Interaction Study Between Raltegravir and Atorvastatin 20 mg in Healthy Volunteers

    NARCIS (Netherlands)

    Blonk, M.I.; Beek, M. van; Colbers, A.; Schouwenberg, B.J.; Burger, D.M.

    2015-01-01

    BACKGROUND: Dyslipidemia is highly prevalent among patients with HIV infection and contributes to an increased risk of cardiovascular disease. We investigated the influence of a frequently used statin, atorvastatin, on the pharmacokinetics of the HIV-integrase inhibitor raltegravir and vice versa.

  10. Clinical Drug-Drug Pharmacokinetic Interaction Potential of Sucralfate with Other Drugs

    DEFF Research Database (Denmark)

    Sulochana, Suresh P; Syed, Muzeeb; Chandrasekar, Devaraj V

    2016-01-01

    of drugs. This review covers several category of drugs such as non-steroidal anti-inflammatory drugs, fluoroquinolones, histamine H2-receptor blockers, macrolides, anti-fungals, anti-diabetics, salicylic acid derivatives, steroidal anti-inflammatory drugs and provides pharmacokinetic data summary along...

  11. Significance of likes: Analysing passive interactions on Facebook during campaigning

    OpenAIRE

    Khairuddin, Mohammad Adib; Rao, Asha

    2017-01-01

    With more and more political candidates using social media for campaigning, researchers are looking at measuring the effectiveness of this medium. Most research, however, concentrates on the bare count of likes (or twitter mentions) in an attempt to correlate social media presence and winning. In this paper, we propose a novel method, Interaction Strength Plot (IntS) to measure the passive interactions between a candidate's posts on Facebook and the users (liking the posts). Using this method...

  12. Bioavailability of Lumefantrine Is Significantly Enhanced with a Novel Formulation Approach, an Outcome from a Randomized, Open-Label Pharmacokinetic Study in Healthy Volunteers.

    Science.gov (United States)

    Jain, Jay Prakash; Leong, F Joel; Chen, Lan; Kalluri, Sampath; Koradia, Vishal; Stein, Daniel S; Wolf, Marie-Christine; Sunkara, Gangadhar; Kota, Jagannath

    2017-09-01

    The artemether-lumefantrine combination requires food intake for the optimal absorption of lumefantrine. In an attempt to enhance the bioavailability of lumefantrine, new solid dispersion formulations (SDF) were developed, and the pharmacokinetics of two SDF variants were assessed in a randomized, open-label, sequential two-part study in healthy volunteers. In part 1, the relative bioavailability of the two SDF variants was compared with that of the conventional formulation after administration of a single dose of 480 mg under fasted conditions in three parallel cohorts. In part 2, the pharmacokinetics of lumefantrine from both SDF variants were evaluated after a single dose of 480 mg under fed conditions and a single dose of 960 mg under fasted conditions. The bioavailability of lumefantrine from SDF variant 1 and variant 2 increased up to ∼48-fold and ∼24-fold, respectively, relative to that of the conventional formulation. Both variants demonstrated a positive food effect and a less than proportional increase in exposure between the 480-mg and 960-mg doses. Most adverse events (AEs) were mild to moderate in severity and not suspected to be related to the study drug. All five drug-related AEs occurred in subjects taking SDF variant 2. No clinically significant treatment-emergent changes in vital signs, electrocardiograms, or laboratory blood assessments were noted. The solid dispersion formulation enhances the lumefantrine bioavailability to a significant extent, and SDF variant 1 is superior to SDF variant 2. Copyright © 2017 Jain et al.

  13. Pharmacokinetic-pharmacodynamic modeling of the antihypertensive interaction between azilsartan medoxomil and chlorthalidone in spontaneously hypertensive rats.

    Science.gov (United States)

    Kumar Puttrevu, Santosh; Ramakrishna, Rachumallu; Bhateria, Manisha; Jain, Moon; Hanif, Kashif; Bhatta, Rabi Sankar

    2017-05-01

    A pharmacokinetic-pharmacodynamic (PK-PD) model was developed to describe the time course of blood pressure following oral administration of azilsartan medoxomil (AZM) and/or chlorthalidone (CLT) in spontaneously hypertensive (SH) rats. The drug concentration and pharmacological effects, including systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and tail-cuff manometry, respectively. Sequential PK-PD analysis was performed, wherein the plasma concentration-time data was modeled by one compartmental analysis. Subsequently PD parameters were calculated to describe the time-concentration-response relationship using indirect response (IDR) PK-PD model. The combination of AZ and CLT had greater BP lowering effect compared to AZ or CLT alone, despite of no pharmacokinetic interaction between two drugs. These findings suggest synergistic antihypertensive pharmacodynamic interaction between AZ and CLT noncompetitively, which was simulated by inhibitory function of AZ and stimulatory function of CLT after concomitant administration of the two drugs. The present model was able to capture the turnover of blood pressure adequately at different time points at two different dose levels. The current PK-PD model was successfully utilized in the simulation of PD effect at a dose combination of 0.5 and 2.5 mg/kg for AZ and CLT, respectively. The developed preclinical PK-PD model may provide guidance in the optimization of dose ratio of individual drugs in the combined pharmacotherapy of AZ and CLT at clinical situations.

  14. Evidence for a pharmacokinetic interaction between eslicarbazepine and rosuvastatin: Potential effects on xenobiotic transporters.

    Science.gov (United States)

    Gidal, Barry E; Mintzer, Scott; Schwab, Matthias; Schutz, Ralph; Kharidia, Jahnavi; Blum, David; Grinnell, Todd; Sunkaraneni, Soujanya

    2017-09-01

    Patients with partial-onset seizures and comorbid cardiovascular disease may concomitantly receive eslicarbazepine acetate (ESL), an antiepileptic drug, and rosuvastatin, an HMG-CoA reductase inhibitor. This study evaluated the effect of multiple-dose ESL on the pharmacokinetic (PK) parameters of a single dose of rosuvastatin in healthy subjects. This was a Phase I, single-center, fixed-sequence, open-label study. Healthy subjects received two treatments, in sequence. Treatment A: a single 40mg oral dose of rosuvastatin on Day 1, followed by a washout period (Days 1-4); treatment B: titration of ESL (400-800mg once daily) on Days 5-18, followed by ESL 1200mg once daily on Days 19-35, with a single dose of rosuvastatin (40mg) on Day 32. Subjects then entered a 2-week follow-up period. Plasma concentrations of rosuvastatin were quantified for PK analyses. Safety and tolerability were assessed throughout the study. Thirty-three healthy subjects were enrolled and 30 completed the study. Mean rosuvastatin (standard deviation) t 1/2 was similar when rosuvastatin was used concomitantly with ESL and when it was used alone (26.5 [16.3]h, and 22.4 [9.5]h, respectively). The geometric least squares mean ratios (90% confidence intervals) of rosuvastatin exposure levels between rosuvastatin used concomitantly with ESL and rosuvastatin used alone were as follows: C max , 64.0% (55.9-73.3%); AUC (0-∞) , 63.0% (57.1-69.4%); and AUC (0-last) , 60.9% (55.2-67.1%). Concomitant use of ESL and rosuvastatin was generally well tolerated. Rosuvastatin exposure was 36-39% lower with steady-state administration of ESL, potentially due to reduced oral bioavailability of rosuvastatin. Consequently, when rosuvastatin is used with ESL, a rosuvastatin dose adjustment may be necessary if a clinically significant change in lipids is noted. Copyright © 2017. Published by Elsevier B.V.

  15. Pharmacokinetic and pharmacodynamic herb-drug interaction of Andrographis paniculata (Nees) extract and andrographolide with etoricoxib after oral administration in rats.

    Science.gov (United States)

    Balap, Aishwarya; Atre, Bhagyashri; Lohidasan, Sathiyanarayanan; Sinnathambi, Arulmozhi; Mahadik, Kakasaheb

    2016-05-13

    Andrographis paniculata Nees (Acanthacae) is commonly used medicinal plant in the traditional. Unani and Ayurvedic medicinal systems. It has broad range of pharmacological effects such as hepatoprotective, antioxidant, antivenom, antifertility, inhibition of replication of the HIV virus, antimalarial, antifungal, antibacterial, antidiabetic, suppression of various cancer cells and anti-inflammatory properties. Andrographolide (AN) is one of the active constituent of the A. paniculata Nees extract (APE). They have been found in many traditional herbal formulations in India and proven to be effective as anti-inflammatory drug To evaluate the pharmacokinetic and pharmacodynamic (anti-arthritic) herb-drug interactions of A. paniculata Nees extract (APE) and pure andrographolide (AN) with etoricoxib (ETO) after oral co-administration in wistar rats. After oral co-administration of APE (200mg/Kg) and AN (60mg/kg) with ETO (10mg/kg) in rats, drug concentrations in plasma were determined using HPLC method. The main pharmacokinetic parameters of Cmax, tmax, t1/2, MRT, Vd, CL, and AUC were calculated by non-compartment model. Change in paw volume, mechanical nociceptive threshold, mechanical hyperalgesia, histopathology and hematological parameters were evaluated to study antiarthritic activity. Co-administration of ETO with APE and pure AN decreased systemic exposure level of each compound in vivo. The Cmax, AUC, t1/2 of ETO was decreased whereas Vd and CL of ETO was increased significantly after co-administration of ETO with pure AN and APE. In pharmacodynamic study, ETO alone and ETO+APE (10+200mg/kg) groups exhibited significant synergistic anti-arthritic activity as compared to groups ETO+AN, APE and AN alone. The results obtained from this study suggested that ETO, APE and pure AN existed pharmacokinetic herb-drug interactions in rat which is correlated with anti-arthritic study. Physicians and patients using A. paniculata should have the knowledge about its possible

  16. A Single-Center, Open-Label, 3-Way Crossover Trial to Determine the Pharmacokinetic and Pharmacodynamic Interaction Between Nebivolol and Valsartan in Healthy Volunteers at Steady State.

    Science.gov (United States)

    Chen, Chun Lin; Desai-Krieger, Daksha; Ortiz, Stephan; Kerolous, Majid; Wright, Harold M; Ghahramani, Parviz

    2015-01-01

    Combining different classes of antihypertensives is more effective for reducing blood pressure (BP) than increasing the dose of monotherapies. The aims of this phase I study were to investigate pharmacokinetic and pharmacodynamic interactions between nebivolol, a vasodilatory β1-selective blocker, and valsartan, an angiotensin II receptor blocker, and to assess safety and tolerability of the combination. This was a single-center, randomized, open-label, multiple-dose, 3-way crossover trial in 30 healthy adults aged 18-45 years. Participants were randomized into 1 of 6 treatment sequences (1:1:1:1:1:1) consisting of three 7-day treatment periods followed by a 7-day washout. Once-daily oral treatments comprised nebivolol (20 mg), valsartan (320 mg), and nebivolol-valsartan combination (20/320 mg). Outcomes included AUC0-τ,ss, Cmax,ss, Tmax,ss, changes in BP, pulse rate, plasma angiotensin II, plasma renin activity, 24-hour urinary aldosterone, and adverse events. Steady-state pharmacokinetic interactions were observed but deemed not clinically significant. Systolic and diastolic BP reduction was significantly greater with nebivolol-valsartan combination than with either monotherapy. The mean pulse rate associated with nebivolol and nebivolol-valsartan treatments was consistently lower than that associated with valsartan monotherapy. A sharp increase in mean day 7 plasma renin activity and plasma angiotensin II that occurred in valsartan-treated participants was significantly attenuated with concomitant nebivolol administration. Mean 24-hour urine aldosterone at day 7 was substantially decreased after combined treatment, as compared with either monotherapy. All treatments were safe and well tolerated. In conclusion, nebivolol and valsartan coadministration led to greater reductions in BP compared with either monotherapy; nebivolol and valsartan lower BP through complementary mechanisms.

  17. Significance of likes: Analysing passive interactions on Facebook during campaigning.

    Directory of Open Access Journals (Sweden)

    Mohammad Adib Khairuddin

    Full Text Available With more and more political candidates using social media for campaigning, researchers are looking at measuring the effectiveness of this medium. Most research, however, concentrates on the bare count of likes (or twitter mentions in an attempt to correlate social media presence and winning. In this paper, we propose a novel method, Interaction Strength Plot (IntS to measure the passive interactions between a candidate's posts on Facebook and the users (liking the posts. Using this method on original Malaysian General Election (MGE13 and Australian Federal Elections (AFE13 Facebook Pages (FP campaign data, we label an FP as performing well if both the posting frequency and the likes gathered are above average. Our method shows that over 60% of the MGE13 candidates and 85% of the AFE13 candidates studied in this paper had under-performing FP. Some of these FP owners would have been identified as popular based on bare count. Thus our performance chart is a vital step forward in measuring the effectiveness of online campaigning.

  18. Significance of likes: Analysing passive interactions on Facebook during campaigning.

    Science.gov (United States)

    Khairuddin, Mohammad Adib; Rao, Asha

    2017-01-01

    With more and more political candidates using social media for campaigning, researchers are looking at measuring the effectiveness of this medium. Most research, however, concentrates on the bare count of likes (or twitter mentions) in an attempt to correlate social media presence and winning. In this paper, we propose a novel method, Interaction Strength Plot (IntS) to measure the passive interactions between a candidate's posts on Facebook and the users (liking the posts). Using this method on original Malaysian General Election (MGE13) and Australian Federal Elections (AFE13) Facebook Pages (FP) campaign data, we label an FP as performing well if both the posting frequency and the likes gathered are above average. Our method shows that over 60% of the MGE13 candidates and 85% of the AFE13 candidates studied in this paper had under-performing FP. Some of these FP owners would have been identified as popular based on bare count. Thus our performance chart is a vital step forward in measuring the effectiveness of online campaigning.

  19. A quantitative systems pharmacology approach, incorporating a novel liver model, for predicting pharmacokinetic drug-drug interactions.

    Science.gov (United States)

    Cherkaoui-Rbati, Mohammed H; Paine, Stuart W; Littlewood, Peter; Rauch, Cyril

    2017-01-01

    All pharmaceutical companies are required to assess pharmacokinetic drug-drug interactions (DDIs) of new chemical entities (NCEs) and mathematical prediction helps to select the best NCE candidate with regard to adverse effects resulting from a DDI before any costly clinical studies. Most current models assume that the liver is a homogeneous organ where the majority of the metabolism occurs. However, the circulatory system of the liver has a complex hierarchical geometry which distributes xenobiotics throughout the organ. Nevertheless, the lobule (liver unit), located at the end of each branch, is composed of many sinusoids where the blood flow can vary and therefore creates heterogeneity (e.g. drug concentration, enzyme level). A liver model was constructed by describing the geometry of a lobule, where the blood velocity increases toward the central vein, and by modeling the exchange mechanisms between the blood and hepatocytes. Moreover, the three major DDI mechanisms of metabolic enzymes; competitive inhibition, mechanism based inhibition and induction, were accounted for with an undefined number of drugs and/or enzymes. The liver model was incorporated into a physiological-based pharmacokinetic (PBPK) model and simulations produced, that in turn were compared to ten clinical results. The liver model generated a hierarchy of 5 sinusoidal levels and estimated a blood volume of 283 mL and a cell density of 193 × 106 cells/g in the liver. The overall PBPK model predicted the pharmacokinetics of midazolam and the magnitude of the clinical DDI with perpetrator drug(s) including spatial and temporal enzyme levels changes. The model presented herein may reduce costs and the use of laboratory animals and give the opportunity to explore different clinical scenarios, which reduce the risk of adverse events, prior to costly human clinical studies.

  20. A quantitative systems pharmacology approach, incorporating a novel liver model, for predicting pharmacokinetic drug-drug interactions.

    Directory of Open Access Journals (Sweden)

    Mohammed H Cherkaoui-Rbati

    Full Text Available All pharmaceutical companies are required to assess pharmacokinetic drug-drug interactions (DDIs of new chemical entities (NCEs and mathematical prediction helps to select the best NCE candidate with regard to adverse effects resulting from a DDI before any costly clinical studies. Most current models assume that the liver is a homogeneous organ where the majority of the metabolism occurs. However, the circulatory system of the liver has a complex hierarchical geometry which distributes xenobiotics throughout the organ. Nevertheless, the lobule (liver unit, located at the end of each branch, is composed of many sinusoids where the blood flow can vary and therefore creates heterogeneity (e.g. drug concentration, enzyme level. A liver model was constructed by describing the geometry of a lobule, where the blood velocity increases toward the central vein, and by modeling the exchange mechanisms between the blood and hepatocytes. Moreover, the three major DDI mechanisms of metabolic enzymes; competitive inhibition, mechanism based inhibition and induction, were accounted for with an undefined number of drugs and/or enzymes. The liver model was incorporated into a physiological-based pharmacokinetic (PBPK model and simulations produced, that in turn were compared to ten clinical results. The liver model generated a hierarchy of 5 sinusoidal levels and estimated a blood volume of 283 mL and a cell density of 193 × 106 cells/g in the liver. The overall PBPK model predicted the pharmacokinetics of midazolam and the magnitude of the clinical DDI with perpetrator drug(s including spatial and temporal enzyme levels changes. The model presented herein may reduce costs and the use of laboratory animals and give the opportunity to explore different clinical scenarios, which reduce the risk of adverse events, prior to costly human clinical studies.

  1. Hypericum perforatum: pharmacokinetic, mechanism of action, tolerability, and clinical drug-drug interactions.

    Science.gov (United States)

    Russo, Emilio; Scicchitano, Francesca; Whalley, Benjamin J; Mazzitello, Carmela; Ciriaco, Miriam; Esposito, Stefania; Patanè, Marinella; Upton, Roy; Pugliese, Michela; Chimirri, Serafina; Mammì, Maria; Palleria, Caterina; De Sarro, Giovambattista

    2014-05-01

    Hypericum perforatum (HP) belongs to the Hypericaceae family and is one of the oldest used and most extensively investigated medicinal herbs. The medicinal form comprises the leaves and flowering tops of which the primary ingredients of interest are naphthodianthrones, xanthones, flavonoids, phloroglucinols (e.g. hyperforin), and hypericin. Although several constituents elicit pharmacological effects that are consistent with HP's antidepressant activity, no single mechanism of action underlying these effects has thus far been found. Various clinical trials have shown that HP has a comparable antidepressant efficacy as some currently used antidepressant drugs in the treatment of mild/moderate depression. Interestingly, low-hyperforin-content preparations are effective in the treatment of depression. Moreover, HP is also used to treat certain forms of anxiety. However, HP can induce various cytochrome P450s isozymes and/or P-glycoprotein, of which many drugs are substrates and which are the main origin of HP-drug interactions. Here, we analyse the existing evidence describing the clinical consequence of HP-drug interactions. Although some of the reported interactions are based on findings from in vitro studies, the clinical importance of which remain to be demonstrated, others are based on case reports where causality can, in some cases, be determined to reveal clinically significant interactions that suggest caution, consideration, and disclosure of potential interactions prior to informed use of HP. Copyright © 2013 John Wiley & Sons, Ltd.

  2. Erroneous analyses of interactions in neuroscience: a problem of significance

    NARCIS (Netherlands)

    Nieuwenhuis, S.; Forstmann, B.U.; Wagenmakers, E.-J.

    2011-01-01

    In theory, a comparison of two experimental effects requires a statistical test on their difference. In practice, this comparison is often based on an incorrect procedure involving two separate tests in which researchers conclude that effects differ when one effect is significant (P < 0.05) but the

  3. Ibrutinib Dosing Strategies Based on Interaction Potential of CYP3A4 Perpetrators Using Physiologically Based Pharmacokinetic Modeling.

    Science.gov (United States)

    de Zwart, L; Snoeys, J; De Jong, J; Sukbuntherng, J; Mannaert, E; Monshouwer, M

    2016-11-01

    Based on ibrutinib pharmacokinetics and potential sensitivity towards CYP3A4-mediated drug-drug interactions (DDIs), a physiologically based pharmacokinetic approach was developed to mechanistically describe DDI with various CYP3A4 perpetrators in healthy men under fasting conditions. These models were verified using clinical data for ketoconazole (strong CYP3A4 inhibitor) and used to prospectively predict and confirm the inducing effect of rifampin (strong CYP3A4 inducer); DDIs with mild (fluvoxamine, azithromycin) and moderate inhibitors (diltiazem, voriconazole, clarithromycin, itraconazole, erythromycin), and moderate (efavirenz) and strong CYP3A4 inducers (carbamazepine), were also predicted. Ketoconazole increased ibrutinib area under the curve (AUC) by 24-fold, while rifampin decreased ibrutinib AUC by 10-fold; coadministration of ibrutinib with strong inhibitors or inducers should be avoided. The ibrutinib dose should be reduced to 140 mg (quarter of maximal prescribed dose) when coadministered with moderate CYP3A4 inhibitors so that exposures remain within observed ranges at therapeutic doses. Thus, dose recommendations for CYP3A4 perpetrator use during ibrutinib treatment were developed and approved for labeling. © 2016 American Society for Clinical Pharmacology and Therapeutics.

  4. Pharmacokinetic interaction of telmisartan with s-amlodipine: an open-label, two-period crossover study in healthy Korean male volunteers.

    Science.gov (United States)

    Noh, Yook-Hwan; Lim, Hyeong-Seok; Kim, Mi Jo; Kim, Yo Han; Choi, Hee Youn; Sung, Hye Ryoung; Jin, Seok-Joon; Lim, Jonglae; Bae, Kyun-Seop

    2012-07-01

    Telmisartan belongs to a class of orally active angiotensin II receptor blockers (ARBs), and S-amlodipine is an enantiomer of amlodipine. Amlodipine is a racemic mixture and the calcium channel blocking (CCB) effect is confined to S-amlodipine, whereas R-amlodipine has a 1000-fold lower activity and no racemization occurs in vivo in human plasma. Combination therapy of ARBs with CCBs provides advantages for blood pressure control and vascular protection over monotherapy. To investigate the effects of coadministration of telmisartan and S-amlodipine on the steady-state pharmacokinetic properties of each drug as a drug-drug interaction study required before developing the fixed-dose combination agent. This study comprised 2 separate parts, A and B; each was a multiple-dose, open-label, 2-sequence, 2-period, crossover study in healthy male Korean volunteers. In part A, volunteers were administered 80 mg of telmisartan, either alone or with 5 mg of S-amlodipine. In part B, volunteers were administered 5 mg of S-amlodipine, either alone or with 80 mg of telmisartan. Blood samples were taken on days 9 and 37, following the final dose of each treatment, and at 0 (predose), 0.5, 1, 1.5, 2, 3, 4, 5, 6, 8, 10, 12, and 24 hours after administration in part A, and were taken at 0 (predose), 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, and 24 hours after administration in part B. Plasma concentrations were determined using LC-MS/MS. The pharmacokinetic properties of each drug after coadministration of telmisartan and S-amlodipine were compared with those of each drug administered alone. Tolerability was assessed using measurements of vital signs, clinical chemistry tests, and interviews. Fifty-six volunteers were enrolled (32 in part A and 24 in part B), and all completed except 4 volunteers (3 withdrawn in part A and 1 withdrawn in part B). The geometric mean ratios (GMRs) (90% CI) for the C(max,ss) and AUC(τ,ss) of telmisartan (with or without S-amlodipine) were 1.039 (0

  5. A study of potential pharmacokinetic and pharmacodynamic interactions between dextromethorphan/quinidine and memantine in healthy volunteers.

    Science.gov (United States)

    Pope, Laura E; Schoedel, Kerri A; Bartlett, Cynthia; Sellers, Edward M

    2012-08-01

    Dextromethorphan/quinidine (DMQ) is the first agent indicated for the treatment of pseudobulbar affect. Dextromethorphan, the active ingredient, is a low-affinity, uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist. This study evaluated the potential for a drug-drug interaction (DDI) of DMQ with memantine, which is also an NMDA receptor antagonist. This open-label, randomized, parallel-group study enrolled healthy adults who were randomized into one of two treatment groups. Group 1 subjects were administered memantine at a starting dose of 5 mg once daily, which was titrated over a 3-week period to a dose of 10 mg twice daily (every 12 hours) and continued for another 11 days to attain steady state; DMQ 30 mg (dextromethorphan 30 mg/quinidine 30 mg) every 12 hours was then added for a further 8 days. Group 2 subjects received DMQ 30 mg every 12 hours for 8 days to attain steady state; memantine was then added, titrated on the same schedule as in group 1, and continued at 10 mg every 12 hours for an additional 11 days. Pharmacokinetic blood sampling was performed to assess the primary endpoints of the 90% confidence intervals (CIs) for the geometric mean ratios of the areas under the plasma concentration-time curves (AUCs) for memantine, dextromethorphan, dextrorphan - the dextromethorphan metabolite - and quinidine during concomitant therapy versus monotherapy. Safety/tolerability and pharmacodynamic variables were also assessed. A total of 52 subjects were randomized. In both group 1 (n = 23) and group 2 (n = 29), the 90% CIs for the ratios of the AUCs during concomitant therapy versus monotherapy were within the predefined range to indicate similarity (0.8-1.25) for memantine, dextromethorphan and dextrorphan, indicating no pharmacokinetic DDI. The 90% CI for the AUC ratio for quinidine was slightly above the predefined range; however, the mean AUC increased by only 25%. In both groups, incidence of adverse events was similar, and pharmacodynamic

  6. Pharmacokinetic evaluation of the interaction between oral kaempferol and ethanol in rats.

    Science.gov (United States)

    Zhou, Zhaoxiang; Wang, Meng; Guo, Zengjun; Zhang, Xiaoying

    2016-12-01

    This study was aimed at investigating the effect of ethanol on oral bioavailability of kaempferol in rats, namely, at disclosing their possible interaction. Kaempferol (100 or 250 mg kg-1 bm) was administered to the rats by oral gavage with or without ethanol (600 mg kg-1 bm) co-administration. Intravenous administration (10 and 25 mg kg-1 bm) of kaempferol was used to determine the bioavailability. The concentration of kaempferol in plasma was estimated by ultra high performance liquid chromatography. During coadministration, a significant increase of the area under the plasma concentration-time curve as well as the peak concentration were observed, along with a dramatic decrease in total body clearance. Consequently, the bioavailability of kaempferol in oral control groups was 3.1 % (100 mg kg-1 bm) and 2.1 % (250 mg kg-1 bm). The first was increased by 4.3 % and the other by 2.8 % during ethanol co-administration. Increased permeability of cell membrane and ethanolkaempferol interactions on CYP450 enzymes may enhance the oral bioavailability of kaempferol in rats.

  7. Risk of Clinically Relevant Pharmacokinetic-based Drug-drug Interactions with Drugs Approved by the U.S. Food and Drug Administration Between 2013 and 2016.

    Science.gov (United States)

    Yu, Jingjing; Zhou, Zhu; Tay-Sontheimer, Jessica; Levy, Rene H; Ragueneau-Majlessi, Isabelle

    2018-03-23

    A total of 103 drugs (including 14 combination drugs) were approved by the U.S. Food and Drug Administration from 2013 to 2016. Pharmacokinetic-based drug interaction profiles were analyzed using the University of Washington Drug Interaction Database and the clinical relevance of these observations was characterized based on information from New Drug Application reviews. CYP3A was identified as a major contributor to clinical drug-drug interactions (DDIs), involved in approximately 2/3 of all interactions. Transporters (alone or with enzymes) were found to participate in about half of all interactions, although most of these were weak-to-moderate interactions. When considered as victims, eight new molecular entities (NMEs; cobimetinib, ibrutnib, isavuconazole, ivabradine, naloxegol, paritaprevir, simeprevir, and venetoclax) were identified as sensitive substrates of CYP3A, two NMEs (pirfenidone and tasimelteon) were sensitive substrates of CYP1A2, one NME (dasabuvir) was a sensitive substrate of CYP2C8, one NME (eliglustat) was a sensitive substrate of CYP2D6, and one NME (grazoprevir) was a sensitive substrate of OATP1B1/3 (with changes in exposure greater than 5-fold when co-administered with a strong inhibitor). Interestingly, approximately 75% of identified CYP3A substrates were also substrates of P-gp. As perpetrators, most clinical DDIs involved weak-to-moderate inhibition or induction, with only two drugs (Viekira Pak and idelalisib) showing strong inhibition of CYP3A, and one NME (lumacaftor) considered as a strong CYP3A inducer. Among drugs with large changes in exposure (≥ 5-fold), whether as victim or perpetrator, the most represented therapeutic classes were antivirals and oncology drugs, suggesting a significant risk of clinical DDIs in these patient populations. The American Society for Pharmacology and Experimental Therapeutics.

  8. Metal ion-oxytetracycline pharmacokinetic interactions after oral co-administration in broiler chickens.

    Science.gov (United States)

    Ziółkowski, H; Jasiecka, A; Zuśka-Prot, M; Przybysz, J; Grabowski, T; Jaroszewski, J J

    2016-08-01

    The influence of the composition of calcium (Ca(2+)), magnesium (Mg(2+)), and iron (Fe(3+)) ions in two concentration levels (low-500 mg/L of CaCl2, 125 mg/L of MgCl2, and 10 mg/L of FeCl3 and high-2,500 mg/L of CaCl2, 625 mg/L of MgCl2, and 50 mg/L of FeCl3) contained in water on the pharmacokinetics (PK) of oxytetracycline (OTC) was determined. OTC hydrochloride was administered at a dose of 25 mg/kg of body weight to broiler chickens divided into four groups of nine birds each, including 3 oral groups (in deionized water -control, in water with low ion concentration, and in water with high ion concentration) and 1 intravenous group. OTC concentrations in plasma were determined using liquid chromatography-tandem mass spectrometry, after which non-compartmental pharmacokinetic analysis was conducted.The absolute bioavailability of OTC in the group of birds exposed to higher ions concentration was reduced (8.68% ± 2.56) as compared to the control (13.71% ± 2.60). Additionally, in this group, decrease in PK parameters such as: area under the concentration-time curve from 0 to infinity (15.36 μg × h/mL ± 4.36), from 0 to t (14.78 μg × h/mL ± 4.37), area under the first moment of curve from 0 to t (107.54 μg × h/mL ± 36.48), and maximum plasma concentration (2.13 μg/mL ± 0.32) were also observed. It is noteworthy, all mentioned parameters demonstrated a downward trend with high correlation coefficient (P = 0.004, P = 0.002, P = 0.005, P = 0.004, P = 0.011, respectively), reflecting the influence of increasing concentrations of Ca(2+), Mg(2+), and Fe(3+) ions on the decreasing absorption rate of OTC.Based on the current research results, it can be assumed that high concentrations of several ions applied concomitantly are able to decrease the absorption of OTC from gastrointestinal tract in broiler chickens. This occurrence might impair the drug's clinical efficacy toward some pathogenic microorganisms. It implies that using OTC on a farm may require

  9. Assessment of pharmacokinetic interaction between piracetam and l-carnitine in healthy subjects.

    Science.gov (United States)

    Mendes, Gustavo D; Zaffalon, Gabriela Traldi; Silveira, Antonio Sérgio; Ramacciato, Juliana Cama; Motta, Rogério Heládio Lopes; Gagliano-Jucá, Thiago; Lopes, Anibal Gil; de Almeida Magalhães, José Cássio; De Nucci, Gilberto

    2016-04-01

    A rapid, sensitive and specific method for quantifying piracetam in human plasma using Piracetam d-8 as the internal standard (IS) is described. The analyte and the IS were extracted from plasma by one-step precipitation of protein using an acetonitrile (100%). The extracts were analyzed by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry (HPLC-MS/MS). The method had a chromatographic run time of 3.8 min and a linear calibration curve over the range 0.5-50 µg/mL (r > 0.99). This LC-MS-MS procedure was used to assess the bioavailability of two piracetam formulations: piracetam + l-carnitine (Piracar®; 270/330 mg tablet) and piracetam (Nootropil®; 800 mg tablet) in healthy volunteers of both sexes. The geometric means with corresponding 90% confidence interval (CI) for test/reference percentage ratios were 88.49% (90% CI = 81.19 - 96.46) for peak concentration/dose and 102.55% (90% CI = 100.62 - 104.51) for AUCinf /dose. The limit of quantitation of 0.5 µg/mL is well suited for pharmacokinetic studies in healthy volunteers. It was concluded that piracetam (Piracar®; 270/330 mg tablet) has a bioavailability equivalent to the piracetam (Nootropil®; 800 mg tablet) formulation with regard to both the rate and the extent of absorption. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Lisdexamfetamine: A pharmacokinetic review.

    Science.gov (United States)

    Comiran, Eloisa; Kessler, Félix Henrique; Fröehlich, Pedro Eduardo; Limberger, Renata Pereira

    2016-06-30

    Lisdexamfetamine (LDX) is a d-amphetamine (d-AMPH) pro-drug used to treat Attention Deficit and Hyperactivity Disorder (ADHD) and Binge Eating Disorder (BED) symptoms. The in vivo pharmacodynamics of LDX is the same as that of its active product d-AMPH, although there are a few qualitative and quantitative differences due to pharmacokinetics. Due to the specific pharmacokinetics of the long-acting stimulants, this article revises the pharmacokinetic studies on LDX, the newest amphetamine pro-drug. The Medline/Pubmed, Science Direct and Biblioteca Virtual em Saúde (Lilacs and Ibecs) (2007-2016) databases were searched for articles and their list of references. As for basic pharmacokinetics studies, since LDX is a newly developed medication, there are few results concerning biotransformation, distribution and the use of different biological matrices for analysis. This is the first robust review on this topic, gathering data from all clinical pharmacokinetics studies available in the literature. The particular pharmacokinetics of LDX plays a major role in studying this pro-drug, since this knowledge was essential to understand some reports on clinical effects in literature, e.g. the small likelihood of reducing the effect by interactions, the effect of long duration use and the still questionable reduction of the potential for abuse. In general the already well-known pharmacokinetic properties of amphetamine make LDX relatively predictable, simplifying the use of LDX in clinical practice. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Pharmacokinetic Evaluation of the Interactions of Amenamevir (ASP2151) with Ketoconazole, Rifampicin, Midazolam, and Warfarin in Healthy Adults.

    Science.gov (United States)

    Kusawake, Tomohiro; den Adel, Martin; Groenendaal-van de Meent, Dorien; Garcia-Hernandez, Alberto; Takada, Akitsugu; Kato, Kota; Ohtsu, Yoshiaki; Katashima, Masataka

    2017-11-01

    Amenamevir is a nonnucleoside antiherpes virus compound available for treating herpes zoster infections. Four studies aimed to determine any potential interactions between amenamevir and ketoconazole, rifampicin, midazolam, or warfarin in healthy male participants. Two studies were open-label studies that evaluated the effects of multiple doses of ketoconazole (400 mg) and rifampicin (600 mg) on the pharmacokinetics of a single oral dose of amenamevir. The other two studies were randomized, double-blind, parallel-group studies that evaluated the effects of multiple doses of amenamevir on the pharmacokinetics of a single dose of midazolam (7.5 mg) and warfarin (25 mg). A drug interaction was considered to occur if the 90% confidence interval (CI) of the least squares geometric mean ratio (GMR) of amenamevir to the comparator was outside the prespecified interval of 0.80-1.25. Interactions were observed between amenamevir and ketoconazole, rifampicin, and midazolam, but not between amenamevir and warfarin. After a single 400-mg dose of amenamevir, the GMRs of amenamevir plus ketoconazole or rifampicin versus amenamevir alone for C max and the area under the plasma concentration-time curve from time zero to infinity (AUC inf ) were 1.30 (90% CI 1.17-1.45) and 2.58 (90% CI 2.32-2.87), respectively, for ketoconazole and 0.42 (90% CI 0.37-0.49) and 0.17 (90% CI 0.15-0.19), respectively, for rifampicin. Following multiple doses of amenamevir (400 mg), the GMRs of midazolam plus amenamevir versus midazolam alone for AUC inf and C max were 0.53 (90% CI 0.47-0.61) and 0.63 (90% CI 0.50-0.80), respectively. After a single dose of warfarin, the (S)-warfarin and (R)-warfarin mean C max increased and mean AUC inf decreased in the presence of amenamevir; however, the 90% CIs of the GMRs for these parameters remained within the predefined limits. These findings confirm that amenamevir (as a cytochrome P450 3A4 substrate) can interact with ketoconazole or rifampicin, and (as a

  12. Pharmacokinetics: curiosity or cure

    International Nuclear Information System (INIS)

    Notari, R.E.

    1979-01-01

    What is the fate of a drug from the time of its introduction into the body to the end of its duration. Pharmacokinetic studies are often designed to provide an answer to this question. But this question may be asked of any drug and research that is limited to answering it will remain empirical. Pharmacokinetic studies can provide answers to many other drug-related questions. In doing so pharmacokinetic research has the potential of improving drug therapy as well as the design and evaluation of drugs. While significant contributions can be cited, the future of pharmacokinetics depends upon its increased impact on clinical practice and drug design. How can a molecule be tailored for site specificity. Can chemical modification selectively alter absorption, distribution, metabolism, binding or excretion. In what new ways can pharmacokinetic information increase the predictability of drug therapy. Such questions, to which pharmacokinetics should provide answers, are numerous and easily identified. But the definitive studies are difficult both to create and conduct. Whether or not pharmacokinetics can achieve its full potential will depend upon the extent to which it can provide answers to these currently unanswered questions

  13. Severe Rhabdomyolysis from Pharmacokinetic Interaction of Statin in Patient with Diabetic Nephropathy: A Case Report

    Directory of Open Access Journals (Sweden)

    Teerapong Monmaturapoj, M.Sc. in Pharm

    2015-09-01

    Full Text Available Rhabdomyolysis is a potentially life-threatening syndrome characterized by muscle necrosis and the release of intracellular muscle contents into systemic circulation. The authors report a rhabdomyolytic patient with chronic kidney disease who had reduction of renal function owing to undiagnosed hypothyroidism, from drug interaction of simvastatin with gemfibrozil and amlodipine.

  14. Consensus-based evaluation of clinical significance and management of anticancer drug interactions

    NARCIS (Netherlands)

    Jansman, F.G.A.; Reyners, A.K.L.; van Roon, E.N.; Smorenburg, C.H.; Helgason, H.H.; le Comte, M.; Wensveen, B.M.; van den Tweel, A.M.A.; de Blois, M.; Kwee, W.; Kerremans, A.L.; Brouwers, J.R.B.J.

    Background: Anticancer drug interactions can affect the efficacy and toxicity of anticancer treatment and that of the interacting drugs. However, information on the significance, prevention, and management of these interactions is currently lacking. Objective: The purpose of this study was to assess

  15. Evaluation of pharmacokinetic and pharmacodynamic interaction between repaglinide and atazanavir in healthy, diabetic and hepatic impaired rats: possible inhibition of CYP3A, OATP, and P-glycoprotein transporters

    Directory of Open Access Journals (Sweden)

    Thirumal Eswara Goud

    2016-10-01

    Full Text Available The metabolic syndrome in HIV infected patients is particularly associated with the use protease inhibitors. Atazanavir is an inhibitor of the cytochrome P 450 (CYP system, in particular CYP3A4 and CYP2C9 which can affect the metabolism of several drugs. To treat metabolic syndrome in HIV patients repaglinide is used and it is a short acting insulin secretagogues undergoing metabolism with CYP 3A4 and CYP 2C8 enzyme system. The purpose of this study was to assess the possible pharmacokinetic and pharmacodynamic drug interaction of repaglinide and atazanavir in healthy, diabetic and impaired hepatic function rats. Human oral therapeutic doses of atazanavir and repaglinide were extrapolated to rats based on the body surface area. The pharmacokinetic parameters and blood glucose concentrations of repaglinide were determined after oral administration of repaglinide alone (0.5 mg/kg and in the presence of atazanavir (36 mg/kg in normal, diabetic and hepatic impaired rats. The pharmacokinetics (PK and blood glucose concentrations of repaglinide were significantly altered in the presence of atazanavir. The peak plasma concentration (Cmax, area under the plasma concentration time profile (AUC and elimination half-life of repaglinide were significantly (P<0.0001 increased. The repaglinide clearance (CL was significantly (P<0.0001 decreased in the presence of atazanavir treatment. In the presence of atazanavir, repaglinide hypoglycaemic activity was increased significantly (P<0.0001 when compared with the repaglinide control group. The present study demonstrated the significant difference in the PK/PD changes due to the enhanced bioavailability and decreased total body clearance of repaglinide may be due to the inhibition of the CYP P450 metabolic system, OATP and P-gp transporters by atazanavir.

  16. Clinical pharmacokinetics of phenobarbital in neonates

    NARCIS (Netherlands)

    Touw, D J; Graafland, O; Cranendonk, A; Vermeulen, R J; van Weissenbruch, M M

    2000-01-01

    Demographic and clinical pharmacokinetic data collected from term and preterm neonates who were treated with intravenous phenobarbital have been analysed to evaluate the role of patient characteristics in pharmacokinetic parameters. Significant relationships between total body weight (TBW) or body

  17. Pharmacokinetic interaction of finasteride with tamsulosin hydrochloride: an open-label, randomized, 3-period crossover study in healthy Chinese male volunteers.

    Science.gov (United States)

    Chu, Nannan; Xu, Hongrong; Wang, Guoqin; Wang, Jiangdian; Chen, Weili; Yuan, Fei; Yang, Mengjie; Li, Xuening

    2015-02-01

    The primary aim of this study was to evaluate whether there was clinically significant pharmacokinetic (PK) interaction between finasteride and tamsulosin in healthy Chinese male subjects. This was an open-label, randomized, 3-period, crossover study. Subjects received single and multiple doses of 5 mg finasteride alone, single and multiple doses of 0.2 mg tamsulosin hydrochloride sustained-release capsule alone, and single and multiple doses of 5 mg finasteride with 0.2 mg tamsulosin hydrochloride, in an order determined by a computerized randomization schedule. Blood samples were collected up to 48 hours after dosing on study day 1 and up to 24 hours after dosing on study day 9 for determination of plasma concentrations with a validated LC-MS/MS method. Pharmacokinetic parameters were estimated via noncompartmental methods. Tolerability was evaluated by monitoring adverse events, laboratory assays, vital signs, and 12-lead ECG. Fifteen subjects were enrolled, and 14 completed the study. The geometric mean ratios (GMRs) (90% CIs) of AUC(τ,ss) and C(max,ss) values of finasteride at steady state between coadministration of finasteride and tamsulosin hydrochloride and finasteride alone were 1.14 (1.05-1.23) and 1.06 (0.99-1.14), respectively. The GMRs (90% CIs) for AUC(0-t) and C(max) values of finasteride for a single dose of coadministration of finasteride and tamsulosin hydrochloride and finasteride alone were 1.02 (0.94-1.11) and 1.06 (1.01-1.11), respectively. The GMRs (90% CIs) for AUC(τ,ss) and C(max,ss) values of tamsulosin at steady-state for coadministration of finasteride and tamsulosin hydrochloride and tamsulosin hydrochloride alone were 1.18 (1.05-1.33) and 1.23 (1.06-1.43), respectively. The GMRs (90% CIs) for AUC(0-t) and C(max) values of tamsulosin for a single dose of coadministration of finasteride and tamsulosin hydrochloride and tamsulosin hydrochloride alone were 1.04 (0.97-1.10) and 1.04 (0.98-1.11), respectively. Statistical analyses

  18. Evaluation of Drug-Drug Interaction Potential Between Sacubitril/Valsartan (LCZ696) and Statins Using a Physiologically Based Pharmacokinetic Model.

    Science.gov (United States)

    Lin, Wen; Ji, Tao; Einolf, Heidi; Ayalasomayajula, Surya; Lin, Tsu-Han; Hanna, Imad; Heimbach, Tycho; Breen, Christopher; Jarugula, Venkateswar; He, Handan

    2017-05-01

    Sacubitril/valsartan (LCZ696) has been approved for the treatment of heart failure. Sacubitril is an in vitro inhibitor of organic anion-transporting polypeptides (OATPs). In clinical studies, LCZ696 increased atorvastatin C max by 1.7-fold and area under the plasma concentration-time curve by 1.3-fold, but had little or no effect on simvastatin or simvastatin acid exposure. A physiologically based pharmacokinetics modeling approach was applied to explore the underlying mechanisms behind the statin-specific LCZ696 drug interaction observations. The model incorporated OATP-mediated clearance (CL int,T ) for simvastatin and simvastatin acid to successfully describe the pharmacokinetic profiles of either analyte in the absence or presence of LCZ696. Moreover, the model successfully described the clinically observed drug effect with atorvastatin. The simulations clarified the critical parameters responsible for the observation of a low, yet clinically relevant, drug-drug interaction DDI between sacubitril and atorvastatin and the lack of effect with simvastatin acid. Atorvastatin is administered in its active form and rapidly achieves C max that coincide with the low C max of sacubitril. In contrast, simvastatin requires a hydrolysis step to the acid form and therefore is not present at the site of interactions at sacubitril concentrations that are inhibitory. Similar models were used to evaluate the drug-drug interaction risk for additional OATP-transported statins which predicted to maximally result in a 1.5-fold exposure increase. Copyright © 2017. Published by Elsevier Inc.

  19. Randomized, open-label, 5-way crossover study to evaluate the pharmacokinetic/pharmacodynamic interaction between furosemide and the non-steroidal anti-inflammatory drugs diclofenac and ibuprofen in healthy volunteers.

    Science.gov (United States)

    Paterson, C A; Jacobs, D; Rasmussen, S; Youngberg, S P; McGuinness, N

    2011-08-01

    Nonsteroidal anti-inflammatory drugs (NSAIDs) can induce renal complications in patients taking loop diuretics. This study investigated the pharmacokinetic/pharmacodynamic effects and safety profile of orally administered diclofenac sodium, ibuprofen and diclofenac epolamine topical patch (DETP) on furosemide in healthy adult subjects. This open-label, randomized, 5-way crossover study was conducted in 40 subjects (aged 19 - 45 y). Diclofenac (75 mg taken orally twice daily), DETP (1.3% applied topically twice daily), or ibuprofen (800 mg taken orally thrice daily) was administered for 3 consecutive days, followed by co-administration with furosemide (given intravenously as 20 mg/2 min). Plasma furosemide and NSAID concentrations, urine furosemide, sodium and potassium concentrations and urine output were determined throughout the 24 h period following furosemide administration. Orally administered ibuprofen significantly increased furosemide AUC(0-t) (37%) and AUC(0-inf) (36%) and decreased total body CL (27%), R(max) (19%) and CLR (23%) geometric mean ratios compared with furosemide control. Oral and topical diclofenac had no pharmacokinetic effects on furosemide. Ibuprofen increased sodium excretion (Ae(0-24), 16%) and decreased sodium R(max) (15%), and oral diclofenac decreased urine output (Vu(0-24), 15%). DETP had no effect on furosemide pharmacodynamics; total systemic exposure to diclofenac during DETP treatment was diclofenac. Treatments were generally safe, with 25 subjects reporting a total of 112 adverse events. Pharmacodynamic effects were seen with oral diclofenac (urine output) and ibuprofen (urine sodium excretion). Furosemide also affected plasma and urine pharmacokinetic profiles. Pharmacologic effects of DETP on furosemide were not observed under these conditions. Additional research is warranted to delineate the potential interactions of other NSAIDs with furosemide and other loop diuretics.

  20. Co-morbidity and clinically significant interactions between antiepileptic drugs and other drugs in elderly patients with newly diagnosed epilepsy.

    Science.gov (United States)

    Bruun, Emmi; Virta, Lauri J; Kälviäinen, Reetta; Keränen, Tapani

    2017-08-01

    A study was conducted to investigate the frequency of potential pharmacokinetic drug-to-drug interactions in elderly patients with newly diagnosed epilepsy. We also investigated co-morbid conditions associated with epilepsy. From the register of Kuopio University Hospital (KUH) we identified community-dwelling patients aged 65 or above with newly diagnosed epilepsy and in whom use of the first individual antiepileptic drug (AED) began in 2000-2013 (n=529). Furthermore, register data of the Social Insurance Institution of Finland were used for assessing potential interactions in a nationwide cohort of elderly subjects with newly diagnosed epilepsy. We extracted all patients aged 65 or above who had received special reimbursement for the cost of AEDs prescribed on account of epilepsy in 2012 where their first AED was recorded in 2011-2012 as monotherapy (n=1081). Clinically relevant drug interactions (of class C or D) at the time of starting of the first AED, as assessed via the SFINX-PHARAO database, were analysed. Hypertension (67%), dyslipidemia (45%), and ischaemic stroke (32%) were the most common co-morbid conditions in the hospital cohort of patients. In these patients, excessive polypharmacy (more than 10 concomitant drugs) was identified in 27% of cases. Of the patients started on carbamazepine, 52 subjects (32%) had one class-C or class-D drug interaction and 51 (31%) had two or more C- or D-class interactions. Only 2% of the subjects started on valproate exhibited a class-C interaction. None of the subjects using oxcarbazepine displayed class-C or class-D interactions. Patients with 3-5 (OR 4.22; p=0.05) or over six (OR 8.86; p=0.003) other drugs were more likely to have C- or D-class interaction. The most common drugs with potential interactions with carbamazepine were dihydropyridine calcium-blockers, statins, warfarin, and psychotropic drugs. Elderly patients with newly diagnosed epilepsy are at high risk of clinically relevant pharmacokinetic

  1. Microdosing clinical study: pharmacokinetic, pharmacogenomic (SLCO2B1), and interaction (grapefruit juice) profiles of celiprolol following the oral microdose and therapeutic dose.

    Science.gov (United States)

    Ieiri, Ichiro; Doi, Yohei; Maeda, Kazuya; Sasaki, Tomohiro; Kimura, Miyuki; Hirota, Takeshi; Chiyoda, Takeshi; Miyagawa, Mayuko; Irie, Shin; Iwasaki, Kazuhide; Sugiyama, Yuichi

    2012-07-01

    The authors evaluated the contribution of the SLCO2B1 polymorphism to the pharmacokinetics of celiprolol at a microdose (MD) and therapeutic dose (TD) and compared pharmacokinetic proportionality between the 2 dose forms in 30 SLCO2B1 genotype-matched healthy volunteers. Three drugs (celiprolol, fexofenadine, and atenolol) were orally administered as a cassette dosing following the MD (totally 97.5 µg) and then a TD (100 mg) of celiprolol, with and without grapefruit juice. The mean AUC(0-24) of celiprolol was lower in SLCO2B1*3/*3 individuals (775 ng·h/mL) than in *1/*3 (1097 ng·h/mL) and *1/*1 (1547 ng·h/mL) individuals following the TD, and this was confirmed in population pharmacokinetic analysis with statistical significances; however, SLCO2B1 genotype-dependent differences disappeared following the MD. Dose-normalized AUC of celiprolol at the MD was much lower than that at the TD, explained by the saturation of the efflux transporter. Thus, the effect of SLCO2B1 polymorphism on the AUC of celiprolol clearly observed only at the TD may be due to the saturation of the efflux transport systems.

  2. Pubertal status, interaction with significant others, and self-esteem of adolescent girls.

    Science.gov (United States)

    Lacković-Grgin, K; Dekovíc, M; Opacić, G

    1994-01-01

    The aim of this study was to examine the relationship between pubertal status, the quality of interactions with significant others, and the self-esteem of adolescent girls. The model which was tested, hypothesized that pubertal status affects self-esteem through girls' interactions with their parents and friends. Pubertal status was operationalized as the number of months between occurrence of the first menstrual periods and time of the investigation. The measure of self-esteem was the shortened form of the Coopersmith Self-Esteem Inventory. Analyses revealed that girls who begun menstruating six months before the investigation obtained higher scores on the measure of self-esteem than did girls who had been menstruating 13 months or more. The best predictor of self-esteem, however, was the quality of interaction with their mothers. The results support the theoretical view that stresses the importance of interaction with significant others for the development of self-esteem.

  3. Coffee inhibition of CYP3A4 in vitro was not translated to a grapefruit-like pharmacokinetic interaction clinically.

    Science.gov (United States)

    Dresser, George K; Urquhart, Brad L; Proniuk, Julianne; Tieu, Alvin; Freeman, David J; Arnold, John Malcolm; Bailey, David G

    2017-10-01

    Grapefruit can augment oral medication bioavailability through irreversible (mechanism-based) inhibition of intestinal CYP3A4. Supplementary data from our recent coffee-drug interaction clinical study showed some subjects had higher area under the plasma drug concentration - time curve (AUC) and plasma peak drug concentration (Cmax) of the CYP3A4 probe felodipine compared to aqueous control. It was hypothesized that coffee might interact like grapefruit in responsive individuals. Beans from six geographical locations were consistently brewed into coffee that was separated chromatographically to a methanolic fraction for in vitro inhibition testing of CYP3A4 metabolism of felodipine at 1% coffee strength. The effect of simultaneous incubation and 10-min preincubation with coffee fractions determined whether coffee had direct and mechanism-based inhibitory activity. A subsequent five-way randomized balanced controlled crossover clinical study evaluated the clinical pharmacokinetic interaction with single-dose felodipine. Grapefruit juice, water, or three of the in vitro tested coffees were ingested at 300 mL alone 1 h before and then with felodipine. In vitro, all six coffees decreased felodipine metabolism for both simultaneous and preincubation exposure compared to corresponding control. Five coffees demonstrated mechanism-based inhibition. Grapefruit increased felodipine AUC 0-8 (25 vs. 13 ng.h/mL, P coffees caused no change in these parameters compared to water. Despite high in vitro potency of CYP3A4 inhibition, the coffees did not cause a clinical pharmacokinetic interaction possibly from insufficient amount of inhibitor(s) in coffee reaching intestinal CYP3A4 during the absorption phase of felodipine. The results of this study highlight the need for follow-up clinical testing when in vitro results indicate the possibility of an interaction. © 2017 The Authors. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British

  4. Estimation of the binding modes with important human cytochrome P450 enzymes, drug interaction potential, pharmacokinetics, and hepatotoxicity of ginger components using molecular docking, computational, and pharmacokinetic modeling studies.

    Science.gov (United States)

    Qiu, Jia-Xuan; Zhou, Zhi-Wei; He, Zhi-Xu; Zhang, Xueji; Zhou, Shu-Feng; Zhu, Shengrong

    2015-01-01

    Ginger is one of the most commonly used herbal medicines for the treatment of numerous ailments and improvement of body functions. It may be used in combination with prescribed drugs. The coadministration of ginger with therapeutic drugs raises a concern of potential deleterious drug interactions via the modulation of the expression and/or activity of drug-metabolizing enzymes and drug transporters, resulting in unfavorable therapeutic outcomes. This study aimed to determine the molecular interactions between 12 main active ginger components (6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol, 8-shogaol, 10-shogaol, ar-curcumene, β-bisabolene, β-sesquiphelandrene, 6-gingerdione, (-)-zingiberene, and methyl-6-isogingerol) and human cytochrome P450 (CYP) 1A2, 2C9, 2C19, 2D6, and 3A4 and to predict the absorption, distribution, metabolism, excretion, and toxicity (ADMET) of the 12 ginger components using computational approaches and comprehensive literature search. Docking studies showed that ginger components interacted with a panel of amino acids in the active sites of CYP1A2, 2C9, 2C19, 2D6, and 3A4 mainly through hydrogen bond formation, to a lesser extent, via π-π stacking. The pharmacokinetic simulation studies showed that the [I]/[Ki ] value for CYP2C9, 2C19, and 3A4 ranged from 0.0002 to 19.6 and the R value ranged from 1.0002 to 20.6 and that ginger might exhibit a high risk of drug interaction via inhibition of the activity of human CYP2C9 and CYP3A4, but a low risk of drug interaction toward CYP2C19-mediated drug metabolism. Furthermore, it has been evaluated that the 12 ginger components possessed a favorable ADMET profiles with regard to the solubility, absorption, permeability across the blood-brain barrier, interactions with CYP2D6, hepatotoxicity, and plasma protein binding. The validation results showed that there was no remarkable effect of ginger on the metabolism of warfarin in humans, whereas concurrent use of ginger and nifedipine exhibited a

  5. Sunitinib-ibuprofen drug interaction affects the pharmacokinetics and tissue distribution of sunitinib to brain, liver, and kidney in male and female mice differently.

    Science.gov (United States)

    Lau, Christine Li Ling; Chan, Sook Tyng; Selvaratanam, Manimegahlai; Khoo, Hui Wen; Lim, Adeline Yi Ling; Modamio, Pilar; Mariño, Eduardo L; Segarra, Ignacio

    2015-08-01

    Tyrosine kinase inhibitor sunitinib (used in GIST, advanced RCC, and pancreatic neuroendocrine tumors) undergoes CYP3A4 metabolism and is an ABCB1B and ABCG2 efflux transporters substrate. We assessed the pharmacokinetic interaction with ibuprofen (an NSAID used by patients with cancer) in Balb/c male and female mice. Mice (study group) were coadministered (30 min apart) 30 mg/kg of ibuprofen and 60 mg/kg of sunitinib PO and compared with the control groups, which received sunitinib alone (60 mg/kg, PO). Sunitinib concentration in plasma, brain, kidney, and liver was measured by HPLC as scheduled and noncompartmental pharmacokinetic parameters estimated. In female control mice, sunitinib AUC0→∞ decreased in plasma (P brain (P male control mice. After ibuprofen coadministration, female mice showed lower AUC0→∞ in plasma (P brain, liver, and kidney (all P male mice, AUC0→∞ remained unchanged in plasma, increased in liver and kidney, and decreased in brain (all P male and female control mice, but changed after ibuprofen coadministration: Male mice showed 1.6-fold higher liver-to-plasma ratio (P female mice and in kidney (male and female mice) but decreased 55% in brain (P differences. The results illustrate the relevance of this DDI on sunitinib pharmacokinetics and tissue uptake. These may be due to gender-based P450 and efflux/transporters differences. © 2015 Société Française de Pharmacologie et de Thérapeutique.

  6. To study the significance of social interaction for former right wing extremists wanting to disengage

    DEFF Research Database (Denmark)

    Christensen, Tina Wilchen

    2013-01-01

    in investigating the significance of social interaction for former participants in right wing extremist groups, who were in a disengagement process with the help from the organisation Exit in Stockholm, Sweden. As this field involved dealing with people in transition, it also meant dealing with people with very...

  7. A study of pharmacokinetic interactions among co-existing ingredients in Viscum coloratum after intravenous administration of three different preparations to rats.

    Science.gov (United States)

    Ma, Yuying; Fan, Ronghua; Duan, Mengmeng; Yu, Zhiguo; Zhao, Yunli

    2015-01-01

    Viscum coloratum (Komar) Nakai, known as Hujisheng in china, has been widely used as a herb medicine to treat a variety of diseases, including cardiovascular diseases, cancer, hypertension, hepatitis and hemorrhage. The aim was to investigate pharmacokinetic interactions among co-existing ingredients in V. coloratum after intravenous administration of three different preparations (four monomer solutions, the mixture of them and Viscum coloratum extracts) to rats. After protein precipitation pretreatment with plasma samples, high performance liquid chromatographic methods were developed and applied to quantitatively determinate the four components [syringin (Syri), homoeriodictyol-7-O-β-D-glycoside (Hedt-III), homoeriodictyol-7-O-β-D-apiose (1 → 2)-β-D-glycoside (Hedt-II) and homoeriodictyol-7-O-β-D-apiosiyl-(1 → 5)-β-D-apiosyl-(1 → 2)-β-D-glycoside (Hedt-I)]. The pharmacokinetic parameters (Area under the curve [AUC(0-t)], AUC(0-∞), t 1/2) were calculated using DAS 2.1 software (Chinese Pharmacological Society, Shanghai, China) and compared statistically by One-way analysis of variance using SPSS software (18.0, Chicago, IL, USA) with P dialectic view in the research and development processes.

  8. Significant interaction of hypertension and homocysteine on neurological severity in first-ever ischemic stroke patients.

    Science.gov (United States)

    Fan, Ying-Li; Zhan, Rui; Dong, Yi-Fei; Huang, Lei; Ji, Xi-Xin; Lu, Peng; Liu, Jian; Li, Ping; Cheng, Xiao-Shu

    2018-04-03

    It is not known whether combination of hypertension and high homocysteine (HHcy) impacts on stroke-related neurological severity. Our aim was to determine whether there is an interaction of hypertension and HHcy on neurological severity in first-ever ischemic stroke patients. We analyzed neurological severity among 189 consecutive first-ever ischemic stroke patients with or without hypertension or HHcy. Hypertension (odds ratio [OR]: 8.086, 95% confidence interval [CI]: 3.596-18.181, P < .001) and total homocysteine (OR: 1.403, 95% CI: 1.247-1.579, P < .001) were independently associated with neurological severity. In receiver-operating characteristic analysis, total homocysteine was a significant predictor of neurological severity (area under curve: 0.794; P < .001). A multiplicative interaction of hypertension and HHcy on more severe neurological severity was revealed by binary logistic regression (OR: 13.154, 95% CI: 5.293-32.691, P < .001). Analysis further identified a more than multiplicative interaction of hypertension and HHcy on neurological severity compared with patients without each condition (OR: 50.600, 95% CI: 14.775-173.285, P < .001). Interaction effect measured on an additive scale showed that 76.4% patients with moderate/severe neurological severity were attributed to interaction of hypertension and HHcy. Significant interaction of hypertension and HHcy on neurological severity was found on multiplicative and additive scale in first-ever Chinese ischemic stroke patients. Copyright © 2018 American Heart Association. Published by Elsevier Inc. All rights reserved.

  9. Two-way pharmacokinetic interaction studies between saxagliptin and cytochrome P450 substrates or inhibitors: simvastatin, diltiazem extended-release, and ketoconazole

    Directory of Open Access Journals (Sweden)

    Patel C

    2011-06-01

    Full Text Available Chirag G Patel, Li Li, Suzette Girgis, David M Kornhauser, Ernest U Frevert, David W BoultonBristol-Myers Squibb, Princeton, NJ, USABackground: Many medicines, including several cholesterol-lowering agents (eg, lovastatin, simvastatin, antihypertensives (eg, diltiazem, nifedipine, verapamil, and antifungals (eg, ketoconazole are metabolized by and/or inhibit the cytochrome P450 (CYP 3A4 metabolic pathway. These types of medicines are commonly coprescribed to treat comorbidities in patients with type 2 diabetes mellitus (T2DM and the potential for drug-drug interactions of these medicines with new medicines for T2DM must be carefully evaluated.Objective: To investigate the effects of CYP3A4 substrates or inhibitors, simvastatin (substrate, diltiazem (moderate inhibitor, and ketoconazole (strong inhibitor on the pharmacokinetics and safety of saxagliptin, a CYP3A4/5 substrate; and the effects of saxagliptin on these agents in three separate studies.Methods: Healthy subjects were administered saxagliptin 10 mg or 100 mg. Simvastatin, diltiazem extended-release, and ketoconazole doses of 40 mg once daily, 360 mg once daily, and 200 mg twice daily, respectively, were used to determine two-way pharmacokinetic interactions.Results: Coadministration of simvastatin, diltiazem extended-release, or ketoconazole increased mean area under the concentration-time curve values (AUC of saxagliptin by 12%, 109%, and 145%, respectively, versus saxagliptin alone. Mean exposure (AUC of the CYP3A4-generated active metabolite of saxagliptin, 5-hydroxy saxagliptin, decreased with coadministration of simvastatin, diltiazem, and ketoconazole by 2%, 34%, and 88%, respectively. All adverse events were considered mild or moderate in all three studies; there were no serious adverse events or deaths.Conclusion: Saxagliptin, when coadministered with simvastatin, diltiazem extended-release, or ketoconazole, was safe and generally well tolerated in healthy subjects. Clinically

  10. Noise in NC-AFM measurements with significant tip–sample interaction

    Directory of Open Access Journals (Sweden)

    Jannis Lübbe

    2016-12-01

    Full Text Available The frequency shift noise in non-contact atomic force microscopy (NC-AFM imaging and spectroscopy consists of thermal noise and detection system noise with an additional contribution from amplitude noise if there are significant tip–sample interactions. The total noise power spectral density DΔf(fm is, however, not just the sum of these noise contributions. Instead its magnitude and spectral characteristics are determined by the strongly non-linear tip–sample interaction, by the coupling between the amplitude and tip–sample distance control loops of the NC-AFM system as well as by the characteristics of the phase locked loop (PLL detector used for frequency demodulation. Here, we measure DΔf(fm for various NC-AFM parameter settings representing realistic measurement conditions and compare experimental data to simulations based on a model of the NC-AFM system that includes the tip–sample interaction. The good agreement between predicted and measured noise spectra confirms that the model covers the relevant noise contributions and interactions. Results yield a general understanding of noise generation and propagation in the NC-AFM and provide a quantitative prediction of noise for given experimental parameters. We derive strategies for noise-optimised imaging and spectroscopy and outline a full optimisation procedure for the instrumentation and control loops.

  11. Significance of Cuscutain, a cysteine protease from Cuscuta reflexa, in host-parasite interactions

    Directory of Open Access Journals (Sweden)

    Fuchsbauer Hans-Lothar

    2010-10-01

    Full Text Available Abstract Background Plant infestation with parasitic weeds like Cuscuta reflexa induces morphological as well as biochemical changes in the host and the parasite. These modifications could be caused by a change in protein or gene activity. Using a comparative macroarray approach Cuscuta genes specifically upregulated at the host attachment site were identified. Results One of the infestation specific Cuscuta genes encodes a cysteine protease. The protein and its intrinsic inhibitory peptide were heterologously expressed, purified and biochemically characterized. The haustoria specific enzyme was named cuscutain in accordance with similar proteins from other plants, e.g. papaya. The role of cuscutain and its inhibitor during the host parasite interaction was studied by external application of an inhibitor suspension, which induced a significant reduction of successful infection events. Conclusions The study provides new information about molecular events during the parasitic plant - host interaction. Inhibition of cuscutain cysteine proteinase could provide means for antagonizing parasitic plants.

  12. Significance of Cuscutain, a cysteine protease from Cuscuta reflexa, in host-parasite interactions.

    Science.gov (United States)

    Bleischwitz, Marc; Albert, Markus; Fuchsbauer, Hans-Lothar; Kaldenhoff, Ralf

    2010-10-22

    Plant infestation with parasitic weeds like Cuscuta reflexa induces morphological as well as biochemical changes in the host and the parasite. These modifications could be caused by a change in protein or gene activity. Using a comparative macroarray approach Cuscuta genes specifically upregulated at the host attachment site were identified. One of the infestation specific Cuscuta genes encodes a cysteine protease. The protein and its intrinsic inhibitory peptide were heterologously expressed, purified and biochemically characterized. The haustoria specific enzyme was named cuscutain in accordance with similar proteins from other plants, e.g. papaya. The role of cuscutain and its inhibitor during the host parasite interaction was studied by external application of an inhibitor suspension, which induced a significant reduction of successful infection events. The study provides new information about molecular events during the parasitic plant--host interaction. Inhibition of cuscutain cysteine proteinase could provide means for antagonizing parasitic plants.

  13. Displacement of Drugs from Human Serum Albumin: From Molecular Interactions to Clinical Significance.

    Science.gov (United States)

    Rimac, Hrvoje; Debeljak, Željko; Bojić, Mirza; Miller, Larisa

    2017-01-01

    Human serum albumin (HSA) is the most abundant protein in human serum. It has numerous functions, one of which is transport of small hydrophobic molecules, including drugs, toxins, nutrients, hormones and metabolites. HSA has the ability to interact with a wide variety of structurally different compounds. This promiscuous, nonspecific affinity can lead to sudden changes in concentrations caused by displacement, when two or more compounds compete for binding to the same molecular site. It is important to consider drug combinations and their binding to HSA when defining dosing regimens, as this can directly influence drug's free, active concentration in blood. In present paper we review drug interactions with potential for displacement from HSA, situations in which they are likely to occur and their clinical significance. We also offer guidelines in designing drugs with decreased binding to HSA. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  14. Estimation of the binding modes with important human cytochrome P450 enzymes, drug interaction potential, pharmacokinetics, and hepatotoxicity of ginger components using molecular docking, computational, and pharmacokinetic modeling studies

    Directory of Open Access Journals (Sweden)

    Qiu JX

    2015-02-01

    2, 2C9, 2C19, 2D6, and 3A4 mainly through hydrogen bond formation, to a lesser extent, via π–π stacking. The pharmacokinetic simulation studies showed that the [I]/[Ki] value for CYP2C9, 2C19, and 3A4 ranged from 0.0002 to 19.6 and the R value ranged from 1.0002 to 20.6 and that ginger might exhibit a high risk of drug interaction via inhibition of the activity of human CYP2C9 and CYP3A4, but a low risk of drug interaction toward CYP2C19-mediated drug metabolism. Furthermore, it has been evaluated that the 12 ginger components possessed a favorable ADMET profiles with regard to the solubility, absorption, permeability across the blood–brain barrier, interactions with CYP2D6, hepatotoxicity, and plasma protein binding. The validation results showed that there was no remarkable effect of ginger on the metabolism of warfarin in humans, whereas concurrent use of ginger and nifedipine exhibited a synergistic effect on platelet aggregation in humans. Moreover, ginger components showed a rapid half-life and no to low toxicity in humans. Taken together, this study shows that ginger components may regulate the activity and expression of various human CYPs, probably resulting in alterations in drug clearance and response. More studies are warranted to identify and confirm potential ginger–drug interactions and explore possible interactions of ginger with human CYPs and other functionally important proteins, to reduce and avoid side effects induced by unfavorable ginger–drug interactions.Keywords: CYP, drug metabolism, ginger, drug interaction, docking

  15. Chemical ecology of insect-plant interactions: ecological significance of plant secondary metabolites.

    Science.gov (United States)

    Nishida, Ritsuo

    2014-01-01

    Plants produce a diverse array of secondary metabolites as chemical barriers against herbivores. Many phytophagous insects are highly adapted to these allelochemicals and use such unique substances as the specific host-finding cues, defensive substances of their own, and even as sex pheromones or their precursors by selectively sensing, incorporating, and/or processing these phytochemicals. Insects also serve as pollinators often effectively guided by specific floral fragrances. This review demonstrates the ecological significance of such plant secondary metabolites in the highly diverse interactions between insects and plants.

  16. Significant role of the cardiopostural interaction in blood pressure regulation during standing.

    Science.gov (United States)

    Xu, Da; Verma, Ajay K; Garg, Amanmeet; Bruner, Michelle; Fazel-Rezai, Reza; Blaber, Andrew P; Tavakolian, Kouhyar

    2017-09-01

    Cardiovascular and postural control systems have been studied independently despite the increasing evidence showing the importance of cardiopostural interaction in blood pressure regulation. In this study, we aimed to assess the role of the cardiopostural interaction in relation to cardiac baroreflex in blood pressure regulation under orthostatic stress before and after mild exercise. Physiological variables representing cardiovascular control (heart rate and systolic blood pressure), lower limb muscle activation (electromyography), and postural sway (center of pressure derived from force and moment data during sway) were measured from 17 healthy participants (25 ± 2 yr, 9 men and 8 women) during a sit-to-stand test before and after submaximal exercise. The cardiopostural control (characterized by baroreflex-mediated muscle-pump effect in response to blood pressure changes, i.e., muscle-pump baroreflex) was assessed using wavelet transform coherence and causality analyses in relation to the baroreflex control of heart rate. Significant cardiopostural blood pressure control was evident counting for almost half of the interaction time with blood pressure changes that observed in the cardiac baroreflex (36.6-72.5% preexercise and 34.7-53.9% postexercise). Thus, cardiopostural input to blood pressure regulation should be considered when investigating orthostatic intolerance. A reduction of both cardiac and muscle-pump baroreflexes in blood pressure regulation was observed postexercise and was likely due to the absence of excessive venous pooling and a less stressed system after mild exercise. With further studies using more effective protocols evoking venous pooling and muscle-pump activity, the cardiopostural interaction could improve our understanding of the autonomic control system and ultimately lead to a more accurate diagnosis of cardiopostural dysfunctions. NEW & NOTEWORTHY We examined the interaction between cardiovascular and postural control systems during

  17. Quantitation of Metformin in Human Plasma and Urine by Hydrophilic Interaction Liquid Chromatography and Application to a Pharmacokinetic Study

    DEFF Research Database (Denmark)

    Nielsen, Flemming; Hougaard Christensen, Mette Marie; Brøsen, Kim

    2014-01-01

    : We describe an analytical method for the quantification of the widely used antihyperglycemic agent, metformin, in human plasma and urine. The separation was performed using isocratic hydrophilic interaction liquid chromatography on a Luna hydrophilic interaction liquid chromatography column (125...

  18. The significance of GW-SW interactions for biogeochemical processes in sandy streambeds

    Science.gov (United States)

    Arnon, Shai; De Falco, Natalie; Fox, Aryeh; Laube, Gerrit; Schmidt, Christian; Fleckenstein, Jan; Boano, Fulvio

    2015-04-01

    Stream-groundwater interactions have a major impact on hyporheic exchange fluxes in sandy streambeds. However, the physical complexity of natural streams has limited our ability to study these types of interactions systematically, and to evaluate their importance to biogeochemical processes and nutrient cycling. In this work we were able to quantify the effect of losing and gaining fluxes on hyporheic exchange and nutrient cycling in homogeneous and heterogeneous streambeds by combining experiments in laboratory flumes and modeling. Tracer experiments for measuring hyporheic exchange were done using dyes and NaCl under various combinations of overlying water velocity and losing or gaining fluxes. Nutrient cycling experiments were conducted after growing a benthic biofilm by spiking with Sodium Benzoate (as a source of labile dissolved organic carbon, DOC) and measuring DOC and oxygen dynamics. The combination of experimental observations and modeling revealed that interfacial transport increases with the streambed hydraulic conductivity and proportional to the square of the overlying water velocity. Hyporheic exchange fluxes under losing and gaining flow conditions were similar, and became smaller when the losing or gaining flux increases. Increasing in streambed hydraulic conductivity led to higher hyporheic fluxes and reduction in the effects of losing and gaining flow conditions to constrain exchange. Despite the evident effect of flow conditions on hyporheic exchange, labile DOC uptake was positively linked to increasing overlying water velocity but was not affected by losing and gaining fluxes. This is because microbial aerobic activity was taking place at the upper few millimeters of the streambed as shown by local oxygen consumption rates, which was measured using microelectrodes. Based on modeling work, it is expected that GW-SW interaction will be more significant for less labile DOC and anaerobic processes. Our results enable us to study systematically

  19. Opioid analgesics-related pharmacokinetic drug interactions: from the perspectives of evidence based on randomized controlled trials and clinical risk management

    Directory of Open Access Journals (Sweden)

    Feng XQ

    2017-05-01

    Full Text Available Xiu-qin Feng,1 Ling-ling Zhu,2 Quan Zhou3 1Nursing Administration Office, Division of Nursing, 2VIP Care Ward, Division of Nursing, 3Department of Pharmacy, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People’s Republic of China Background: Multimorbidity results in complex polypharmacy which may bear a risk of drug interactions. A better understanding of opioid analgesics combination therapy used for pain management could help warrant medication safety, efficacy, and economic relevance. Until now there has been no review summarizing the opioid analgesics-related pharmacokinetic drug interactions from the perspective of evidence based on randomized controlled trials (RCTs. Method: A literature search was performed using PubMed, MEDLINE, and the Cochrane Library, using a PRISMA flowchart. Results: Fifty-two RCTs were included for data interpretation. Forty-two RCTs (80.8% were conducted in healthy volunteers, whereas 10 RCTs (19.2% enrolled true patients. None of the opioid–drug/herb pairs was listed as contraindications of opioids involved in this review. Circumstances in which opioid is comedicated as a precipitant drug include morphine–P2Y12 inhibitors, morphine–gabapentin, and methadone–zidovudine. Circumstances in which opioid is comedicated as an object drug include rifampin–opioids (morphine, tramadol, oxycodone, methadone, quinidine–opioids (morphine, fentanyl, oxycodone, codeine, dihydrocodeine, methadone, antimycotics–opioids (buprenorphine, fentanyl, morphine, oxycodone, methadone, tilidine, tramadol, protease inhibitors–opioids (ritonavir, ritonavir/lopinavir–oxycodone, ritonavir–fentanyl, ritonavir–tilidine, grapefruit juice–opioids (oxycodone, fentanyl, methadone, antidepressants–opioids (paroxetine–tramadol, paroxetine–hydrocodone, paroxetine–oxycodone, escitalopram–tramadol, metoclopramide–morphine, amantadine–morphine, sumatriptan

  20. The pharmacokinetic behaviour of hypoxoside taken orally by ...

    African Journals Online (AJOL)

    measured with a high-performance liquid chromatography . method. For the ... the South African Medicines Control Council to conduct a phase I pharmacokinetic and ... The significance of various factors that influence the pharmacokinetic ...

  1. Significance of investigating allelopathic interactions of marine organisms in the discovery and development of cytotoxic compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, A.; Thakur, N.L.

    like (1) growth interactions (e.g. overgrowth by corals) [27], (2) aggressive behaviour (e.g., induced development of sweeper tentacles by bryozoans [28], (3) feeding interactions (e.g., extracoelenteric digestion via mesenteries filaments...

  2. The role of alcohol abuse in the etiology of heroin-related deaths. Evidence for pharmacokinetic interactions between heroin and alcohol.

    Science.gov (United States)

    Polettini, A; Groppi, A; Montagna, M

    1999-01-01

    In order to evaluate pharmacokinetic interactions between heroin and alcohol and their role in the etiology of heroin-related deaths (HRD), the alcohol concentration in blood (BAC), the free (FM) and total morphine (TM) concentrations in blood (determined by DPC Coat-A-Count radioimmunoassay before and after enzymatic hydrolysis), and the TM concentration in urine and bile (DPC Coat-A-Count after enzymatic hydrolysis) in a population of 39 lethal cases included in the records of the Department of Legal Medicine and Public Health at the University of Pavia from the period January 1997-April 1998 were examined. The cause of death in each case was attributed to either heroin or associated heroin-ethanol intoxication. Cases were arbitrarily divided into two groups according to BAC (low-ethanol group, LE, BAC 1000 mg/L). The differences in the FM and TM concentrations in blood, bile, and urine and in the FM/TM ratios between the two . groups were statistically evaluated (Mann-Whitney U test). A similar statistical evaluation was carried out on data from a previously published study concerning the disposition of heroin and its metabolites (6-acetylmorphine and morphine) in blood and urine in 23 lethal cases attributed to either heroin or heroin and alcohol intoxication. The values of the following variables in the LE and HE groups were compared: FM, TM, and 6-acetylmorphine concentrations in blood (6-AM); the FM/ (FM + 6-AM) ratio; the FM/TM ratio; and the urinary concentrations of heroin, 6-acetylmorphine, and free morphine. Statistical analyses of data indicated that high BACs are associated with reduced hydrolysis of 6-AM to morphine (FM/[FM + 6-AM], p = 0.0022) and that a good inverse correlation exists between BAC and hydrolysis of 6-AM to morphine (r2 = 0.67). High BACs were also found to be associated with an increased FM/TM ratio and with reduced excretion of free and total morphine. These results suggest the hypothesis that pharmacokinetic interactions between

  3. Clinical Pharmacokinetics of Systemically Administered Antileishmanial Drugs

    NARCIS (Netherlands)

    Kip, Anke E; Schellens, Jan H M; Beijnen, Jos H; Dorlo, Thomas P C

    This review describes the pharmacokinetic properties of the systemically administered antileishmanial drugs pentavalent antimony, paromomycin, pentamidine, miltefosine and amphotericin B (AMB), including their absorption, distribution, metabolism and excretion and potential drug-drug interactions.

  4. Significance of fluid-structure interaction phenomena for containment response to ex-vessel steam explosions

    Energy Technology Data Exchange (ETDEWEB)

    Almstroem, H.; Sundel, T. [National Defence Research Establishment, Stockholm (Sweden); Frid, W.; Engelbrektson, A.

    1998-01-01

    When studying the structural response of a containment building to ex-vessel steam explosion loads, a two-step procedure is often used. In the first step of this procedure the structures are treated as rigid and the pressure-time history generated by the explosion at the rigid wall is calculated. In the second step the calculated pressure is applied to the structures. The obvious weakness of the two-step procedure is that it does not correspond to the real dynamic behaviour of the fluid-structure system. The purpose of this paper is to identify and evaluate the relevant fluid-structure interaction phenomena. This is achieved through direct treatment of the explosion process and the structural response. The predictions of a direct and two-step treatment are compared for a BWR Mark II containment design, consisting of two concentric walls interacting with water masses in the central and annular pools. It is shown that the two-step approach leads to unrealistic energy transfer in the containment system studied, and to significant overestimation of the deflection of the containment wall. As regards the pedestal wall, the direct method analysis shows that the flexibility of this wall affects the pressure-time history considerably. Three load types have been identified for this wall namely shock load, water blow as a result of water cavitation, and hydrodynamic load. Reloading impulse due to cavitation phenomena plays an important role as it amounts to about 40% of the total impulse load. Investigation of the generality of the cavitation phenomena in the context of ex-vessel steam explosion loads was outside the scope of this work. (author)

  5. Significance of fluid-structure interaction phenomena for containment response to ex-vessel steam explosions

    Energy Technology Data Exchange (ETDEWEB)

    Almstroem, H.; Sundel, T. (Nat. Defence Res. Establ., Tumba (Sweden)); Frid, W. (Swedish Nuclear Power Inspectorate, SE-10658, Stockholm (Sweden)); Engelbrektson, A. (VBB/SWECO, Box 34044, SE-10026, Stockholm (Sweden))

    1999-05-01

    When studying the structural response of a containment building to ex-vessel steam explosion loads, a two-step procedure is often used. In the first step of this procedure the structures are treated as rigid and the pressure-time history generated by the explosion, at the rigid wall, is calculated. In the second step the calculated pressure is applied to the structures. The obvious weakness of the two-step procedure is that it does not correspond to the real dynamic behaviour of the fluid-structure system. The purpose of this paper is to identify and evaluate the relevant fluid-structure interaction phenomena. This is achieved through direct treatment of the explosion process and the structural response. The predictions of a direct and two-step treatment are compared for a BWR Mark II containment design, consisting of two concentric walls interacting with water masses in the central and annular pools. It is shown that the two-step approach leads to unrealistic energy transfer in the containment system studied and to significant overestimation of the deflection of the containment wall. As regards the pedestal wall, the direct method analysis shows that the flexibility of this wall affects the pressure-time history considerably. Three load types have been identified for this wall namely shock load, water blow as a result of water cavitation, and hydrodynamic load. Reloading impulse due to cavitation phenomena plays an important role as it amounts to [approx]40% of the total impulse load. Investigation of the generality of the cavitation phenomena in the context of ex-vessel steam explosion loads was outside the scope of this work. (orig.) 5 refs.

  6. Significance of fluid-structure interaction phenomena for containment response to ex-vessel steam explosions

    International Nuclear Information System (INIS)

    Almstroem, H.; Sundel, T.; Frid, W.; Engelbrektson, A.

    1999-01-01

    When studying the structural response of a containment building to ex-vessel steam explosion loads, a two-step procedure is often used. In the first step of this procedure the structures are treated as rigid and the pressure-time history generated by the explosion, at the rigid wall, is calculated. In the second step the calculated pressure is applied to the structures. The obvious weakness of the two-step procedure is that it does not correspond to the real dynamic behaviour of the fluid-structure system. The purpose of this paper is to identify and evaluate the relevant fluid-structure interaction phenomena. This is achieved through direct treatment of the explosion process and the structural response. The predictions of a direct and two-step treatment are compared for a BWR Mark II containment design, consisting of two concentric walls interacting with water masses in the central and annular pools. It is shown that the two-step approach leads to unrealistic energy transfer in the containment system studied and to significant overestimation of the deflection of the containment wall. As regards the pedestal wall, the direct method analysis shows that the flexibility of this wall affects the pressure-time history considerably. Three load types have been identified for this wall namely shock load, water blow as a result of water cavitation, and hydrodynamic load. Reloading impulse due to cavitation phenomena plays an important role as it amounts to ∼40% of the total impulse load. Investigation of the generality of the cavitation phenomena in the context of ex-vessel steam explosion loads was outside the scope of this work. (orig.)

  7. Prognostic significance of Traf2- and Nck- interacting kinase (TNIK) in colorectal cancer

    International Nuclear Information System (INIS)

    Takahashi, Hidenori; Ishikawa, Toshiaki; Ishiguro, Megumi; Okazaki, Satoshi; Mogushi, Kaoru; Kobayashi, Hirotoshi; Iida, Satoru; Mizushima, Hiroshi; Tanaka, Hiroshi; Uetake, Hiroyuki; Sugihara, Kenichi

    2015-01-01

    The potential of expression profiling using microarray analysis as a tool to predict the prognosis for different types of cancer has been realized. This study aimed to identify a novel biomarker for colorectal cancer (CRC). The expression profiles of cancer cells in 152 patients with stage I-III CRC were examined using microarray analysis. High expression in CRC cells, especially in patients with distant recurrences, was a prerequisite to select candidate genes. Thus, we identified seventeen candidate genes, and selected Traf2- and Nck-interacting kinase (TNIK), which was known to be associated with progression in CRC through Wnt signaling pathways. We analyzed the protein expression of TNIK using immunohistochemistry (IHC) and investigated the relationship between protein expression and patient characteristics in 220 stage I-III CRC patients. Relapse-free survival was significantly worse in the TNIK high expression group than in the TNIK low expression group in stage II (p = 0.028) and stage III (p = 0.006) patients. In multivariate analysis, high TNIK expression was identified as a significant independent risk factor of distant recurrence in stage III patients. This study is the first to demonstrate the prognostic significance of intratumoral TNIK protein expression in clinical tissue samples of CRC, in that high expression of TNIK protein in primary tumors was associated with distant recurrence in stage II and III CRC patients. This TNIK IHC study might contribute to practical decision-making in the treatment of these patients. The online version of this article (doi:10.1186/s12885-015-1783-y) contains supplementary material, which is available to authorized users

  8. Some significant but buried studies of embodiment and materiality in social interaction

    DEFF Research Database (Denmark)

    Nevile, Maurice Richard

    When preparing a recent review on rising interest in ‘embodiment’ in EM CA research on social interaction (Nevile 2015) (e.g. gesture, body, mobility; cf. ‘multimodality’), considering over 500 studies, I was delighted to be reminded of, or often ‘discover’, some less-well-known-and-cited studies...... some to highlight from the prominent journal Research on Language and Social Interaction. The paper argues that active recognition of the contribution of the body-in-interaction might be relatively recent, but scholarly awareness of it is not (in EM CA and beyond). My aim is to resurrect some early...... discussion of doing CA and EM as a research community. Goodwin, C. (2000) Action and embodiment within situated human interaction. Journal of Pragmatics, 32, 1489–1522. Nevile, M. (2015) The embodied turn in research on language and social interaction. Research on Language and Social Interaction. 48,2: 121...

  9. The significance of a new correspondence principle for electromagnetic interaction in strong optical field ionisation

    International Nuclear Information System (INIS)

    Boreham, B. W.; Hora, H.

    1997-01-01

    We have recently developed a correspondence principle for electromagnetic interaction. When applied to laser interactions with electrons this correspondence principle identifies a critical laser intensity I*. This critical intensity is a transition intensity separating classical mechanical and quantum mechanical interaction regimes. In this paper we discuss the further application of I* to the interaction of bound electrons in atoms. By comparing I* with the ionisation threshold intensities as calculated from a cycle-averaged simple-atom model we conclude that I* can be usefully interpreted as a lower bound to the classical regime in studies of ionisation of gas atoms by intense laser beams

  10. Evaluation of Pharmacokinetic and Pharmacodynamic Drug-Drug Interaction of Sacubitril/Valsartan (LCZ696) and Sildenafil in Patients With Mild-to-Moderate Hypertension.

    Science.gov (United States)

    Hsiao, H-L; Langenickel, T H; Petruck, J; Kode, K; Ayalasomayajula, S; Schuehly, U; Greeley, M; Pal, P; Zhou, W; Prescott, M F; Sunkara, G; Rajman, I

    2018-03-01

    Sacubitril/valsartan (LCZ696) is indicated for the treatment of patients with heart failure and reduced ejection fraction (HFrEF). Since patients with HFrEF may receive sacubitril/valsartan and sildenafil, both increasing cyclic guanosine monophosphate, the present study evaluated the pharmacokinetic and pharmacodynamic drug interaction potential between sacubitril/valsartan and sildenafil. In this open-label, three-period, single sequence study, patients with mild-to-moderate hypertension (153.8 ± 8.2 mmHg mean systolic blood pressure (SBP)) received a single dose of sildenafil 50 mg, sacubitril/valsartan 400 mg once daily for 5 days, and sacubitril/valsartan and sildenafil coadministration. When coadministered with sildenafil, the AUC and C max of valsartan decreased by 29% and 39%, respectively. Coadministration of sacubitril/valsartan and sildenafil resulted in a greater decrease in BP (-5/-4/-4 mmHg mean ambulatory SBP/DBP/MAP (mean arterial pressure)) than with sacubitril/valsartan alone. Both treatments were generally safe and well tolerated in this study; however, the additional BP reduction suggests that sildenafil should be administered cautiously in patients receiving sacubitril/valsartan. Unique identifier: NCT01601470. © 2017 The Authors Clinical Pharmacology & Therapeutics published by Wiley Periodicals, Inc. on behalf of American Society for Clinical Pharmacology and Therapeutics.

  11. Evaluation of Pharmacokinetic and Pharmacodynamic Drug–Drug Interaction of Sacubitril/Valsartan (LCZ696) and Sildenafil in Patients With Mild‐to‐Moderate Hypertension

    Science.gov (United States)

    Langenickel, TH; Petruck, J; Kode, K; Ayalasomayajula, S; Schuehly, U; Greeley, M; Pal, P; Zhou, W; Prescott, MF; Sunkara, G; Rajman, I

    2017-01-01

    Sacubitril/valsartan (LCZ696) is indicated for the treatment of patients with heart failure and reduced ejection fraction (HFrEF). Since patients with HFrEF may receive sacubitril/valsartan and sildenafil, both increasing cyclic guanosine monophosphate, the present study evaluated the pharmacokinetic and pharmacodynamic drug interaction potential between sacubitril/valsartan and sildenafil. In this open‐label, three‐period, single sequence study, patients with mild‐to‐moderate hypertension (153.8 ± 8.2 mmHg mean systolic blood pressure (SBP)) received a single dose of sildenafil 50 mg, sacubitril/valsartan 400 mg once daily for 5 days, and sacubitril/valsartan and sildenafil coadministration. When coadministered with sildenafil, the AUC and Cmax of valsartan decreased by 29% and 39%, respectively. Coadministration of sacubitril/valsartan and sildenafil resulted in a greater decrease in BP (–5/–4/–4 mmHg mean ambulatory SBP/DBP/MAP (mean arterial pressure)) than with sacubitril/valsartan alone. Both treatments were generally safe and well tolerated in this study; however, the additional BP reduction suggests that sildenafil should be administered cautiously in patients receiving sacubitril/valsartan. Unique identifier: NCT01601470. PMID:28599060

  12. THE SIGNIFICANCE OF ANTISPERM ANTIBODIES FOR SPERM - CERVICAL-MUCUS INTERACTION

    NARCIS (Netherlands)

    KREMER, J; JAGER, S

    An overview is presented of the effects of antisperm antibodies on the sperm - cervical mucus interaction. Antisperm IgA on spermatozoa or in cervical mucus can severely inhibit sperm penetration of cervical mucus and migration through it. Disturbance of the sperm - cervical mucus interaction is the

  13. Assessment of Pharmacokinetic Interactions Between Obeticholic Acid and Caffeine, Midazolam, Warfarin, Dextromethorphan, Omeprazole, Rosuvastatin, and Digoxin in Phase 1 Studies in Healthy Subjects.

    Science.gov (United States)

    Edwards, Jeffrey E; Eliot, Lise; Parkinson, Andrew; Karan, Sharon; MacConell, Leigh

    2017-09-01

    Obeticholic acid (OCA), a potent and selective farnesoid X receptor agonist, is indicated for the treatment of primary biliary cholangitis (PBC). We investigated the potential drug-drug interaction effect of OCA on metabolic CYP450 enzymes and drug transporters. Five phase 1 single-center, open-label, fixed-sequence, inpatient studies were conducted in healthy adult subjects to evaluate the effect of oral daily doses of 10 or 25 mg OCA on single-dose plasma pharmacokinetics of specific probe substrates for enzymes CYP1A2 (caffeine, R-warfarin), CYP3A (midazolam, R-warfarin), CYP2C9 (S-warfarin), CYP2D6 (dextromethorphan), CYP2C19 (omeprazole), and drug transporters, BCRP/OATP1B1/OATP1B3 (rosuvastatin), and P-gp (digoxin). OCA showed no substantial suppression/inhibition of S-warfarin, digoxin, and dextromethorphan and weak interactions with caffeine, omeprazole, rosuvastatin, and midazolam. The maximal pharmacodynamic responses (E max ) to warfarin-based INR, PT, and aPTT were reduced by 11%, 11%, and 1%, respectively, for the 10-mg dose group and by 7%, 7% and 0%, respectively, for the 25-mg dose group. Overall, drugs dosed in combination with OCA were well tolerated, and most adverse events were mild in severity. No clinically important trends were noted in laboratory evaluations, vital signs, or 12-lead ECGs. In these studies, OCA showed weak to no suppression/inhibition of metabolic enzymes and drug transporters at the highest recommended therapeutic dose in patients with PBC. On the basis on these analyses, monitoring and maintenance of target INR range are required during coadministration of OCA with drugs that are metabolized by CYP1A2 (R-warfarin). Intercept Pharmaceuticals, Inc.

  14. Tacrolimus interaction with nafcillin resulting in significant decreases in tacrolimus concentrations: A case report.

    Science.gov (United States)

    Wungwattana, Minkey; Savic, Marizela

    2017-04-01

    Tacrolimus (TAC) is subject to many drug interactions as a result of its metabolism primarily via CYP450 isoenzyme 3A4. Numerous case reports of TAC and CYP3A4 inducers and inhibitors have been described including antimicrobials, calcium channel antagonists, and antiepileptic drugs. We present the case of a 13-year-old patient with cystic fibrosis and a history of liver transplantation, where subtherapeutic TAC concentrations were suspected to be a result of concomitant TAC and nafcillin (NAF) therapy. The observed drug interaction occurred on two separate hospital admissions, during both of which the patient exhibited therapeutic TAC concentrations prior to exposure to NAF, a CYP3A4 inducer. Upon discontinuation of NAF, TAC concentrations recovered in both instances. This case represents a drug-drug interaction between TAC and NAF that has not previously been reported to our knowledge. Despite the lack of existing reports of interaction between these two agents, this case highlights the importance of therapeutic drug monitoring and assessing for any potential drug-drug or drug-food interactions in patients receiving TAC therapy. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Prediction of Drug-Drug Interactions with Bupropion and Its Metabolites as CYP2D6 Inhibitors Using a Physiologically-Based Pharmacokinetic Model.

    Science.gov (United States)

    Xue, Caifu; Zhang, Xunjie; Cai, Weimin

    2017-12-21

    The potential of inhibitory metabolites of perpetrator drugs to contribute to drug-drug interactions (DDIs) is uncommon and underestimated. However, the occurrence of unexpected DDI suggests the potential contribution of metabolites to the observed DDI. The aim of this study was to develop a physiologically-based pharmacokinetic (PBPK) model for bupropion and its three primary metabolites-hydroxybupropion, threohydrobupropion and erythrohydrobupropion-based on a mixed "bottom-up" and "top-down" approach and to contribute to the understanding of the involvement and impact of inhibitory metabolites for DDIs observed in the clinic. PK profiles from clinical researches of different dosages were used to verify the bupropion model. Reasonable PK profiles of bupropion and its metabolites were captured in the PBPK model. Confidence in the DDI prediction involving bupropion and co-administered CYP2D6 substrates could be maximized. The predicted maximum concentration (C max ) area under the concentration-time curve (AUC) values and C max and AUC ratios were consistent with clinically observed data. The addition of the inhibitory metabolites into the PBPK model resulted in a more accurate prediction of DDIs (AUC and C max ratio) than that which only considered parent drug (bupropion) P450 inhibition. The simulation suggests that bupropion and its metabolites contribute to the DDI between bupropion and CYP2D6 substrates. The inhibitory potency from strong to weak is hydroxybupropion, threohydrobupropion, erythrohydrobupropion, and bupropion, respectively. The present bupropion PBPK model can be useful for predicting inhibition from bupropion in other clinical studies. This study highlights the need for caution and dosage adjustment when combining bupropion with medications metabolized by CYP2D6. It also demonstrates the feasibility of applying the PBPK approach to predict the DDI potential of drugs undergoing complex metabolism, especially in the DDI involving inhibitory

  16. Strong Selection Significantly Increases Epistatic Interactions in the Long-Term Evolution of a Protein.

    Directory of Open Access Journals (Sweden)

    Aditi Gupta

    2016-03-01

    Full Text Available Epistatic interactions between residues determine a protein's adaptability and shape its evolutionary trajectory. When a protein experiences a changed environment, it is under strong selection to find a peak in the new fitness landscape. It has been shown that strong selection increases epistatic interactions as well as the ruggedness of the fitness landscape, but little is known about how the epistatic interactions change under selection in the long-term evolution of a protein. Here we analyze the evolution of epistasis in the protease of the human immunodeficiency virus type 1 (HIV-1 using protease sequences collected for almost a decade from both treated and untreated patients, to understand how epistasis changes and how those changes impact the long-term evolvability of a protein. We use an information-theoretic proxy for epistasis that quantifies the co-variation between sites, and show that positive information is a necessary (but not sufficient condition that detects epistasis in most cases. We analyze the "fossils" of the evolutionary trajectories of the protein contained in the sequence data, and show that epistasis continues to enrich under strong selection, but not for proteins whose environment is unchanged. The increase in epistasis compensates for the information loss due to sequence variability brought about by treatment, and facilitates adaptation in the increasingly rugged fitness landscape of treatment. While epistasis is thought to enhance evolvability via valley-crossing early-on in adaptation, it can hinder adaptation later when the landscape has turned rugged. However, we find no evidence that the HIV-1 protease has reached its potential for evolution after 9 years of adapting to a drug environment that itself is constantly changing. We suggest that the mechanism of encoding new information into pairwise interactions is central to protein evolution not just in HIV-1 protease, but for any protein adapting to a changing

  17. Significance of phage-host interactions for biocontrol of Campylobacter jejuni in food

    DEFF Research Database (Denmark)

    Athina, Zampara; Sørensen, Martine Camilla Holst; Elsser-Gravesen, Anne

    2017-01-01

    Poultry meat is the main source of Campylobacter jejuni foodborne disease. Currently, no effective control measures prevent C. jejuni from contaminating poultry meat. However, post-harvest phage treatment is a promising biocontrol strategy that has not yet been explored. Here we identified phages....... A thorough understanding of phage-host interactions is prerequisite to further advance phage application as a post-harvest biocontrol strategy against C. jejuni....

  18. Effect of grapefruit juice and food on the pharmacokinetics of pirfenidone in healthy Chinese volunteers: a diet-drug interaction study.

    Science.gov (United States)

    Hu, Jinqing; Shang, Dewei; Xu, Xinwen; He, Xiuling; Ni, Xiaojia; Zhang, Ming; Wang, Zhanzhang; Qiu, Chang; Deng, Shuhua; Lu, Haoyang; Zhu, Xiuqing; Huang, Wencan; Wen, Yuguan

    2016-01-01

    1. Ingestion of grapefruit juice and food could be factors affecting the pharmacokinetics of pirfenidone, a promising drug for treatment of idiopathic pulmonary fibrosis. 2. A randomized, open-label, three-period crossover study was carried out in 12 healthy Chinese male volunteers who were randomized to one of the three treatments: pirfenidone tablets (0.4 g) were orally administered to fasted or fed subjects, or with grapefruit juice. The washout period was 7 d. 3. Significantly reduced maximum plasma concentration (Cmax, 5.0 5 ± 1.39 versus 10.9 0 ± 2.94 mg·L(- 1)), modestly affected area-under-the-plasma concentration-time curve (AUC) from time zero to 12 h post dosing (AUC0-12 h, 21.8 9 ± 6.47 versus 26.1 6 ± 7.32 mg·h·L(- 1)) and delayed time to reach Cmax (Tmax) were observed in fed group compared with fasted group. Similar effects on Cmax (5.8 2 ± 1.23 versus 10.9 0 ± 2.94 mg·L(- 1)) and AUC0-12 h (modest but not statistically significant, 24.4 4 ± 7.40 versus 26.1 6 ± 7.32 mg·h·L(- 1)) were observed for grapefruit juice compared to fasted subjects. 4. Co-administration of pirfenidone with grapefruit juice resulted in modestly reduced overall oral absorption and significantly reduced peak concentrations compared to fasting, which was similar to effect of food ingestion. No adverse events were observed in the study, but relatively dramatic reduction of peak concentrations should raise concerns for clinical efficacy and safety.

  19. Structural requirements and biological significance of interactions between peptides and the major histocompatibility complex

    DEFF Research Database (Denmark)

    Grey, H M; Buus, S; Colon, S

    1989-01-01

    Previous studies indicate that T cells recognize a complex between the major histocompatibility complex (MHC) restriction-element and peptide-antigen fragments. Two aspects of this complex formation are considered in this paper: (1) what is the nature of the specificity of the interactions that a...... of binding to Ia (i.e. determinant selection was operative), we found that about 40% of Ia-binding peptides were not immunogenic (i.e. there were also 'holes in the T-cell repertoire')....... responsiveness, we present data that suggest both mechanisms operate in concert with one another. Thus only about 30% of a collection of peptides that in sum represent the sequence of a protein molecule were found to bind to Ia. Although immunogenicity was restricted to those peptides that were capable...

  20. Effect of gemfibrozil and fenofibrate on the pharmacokinetics of atorvastatin.

    Science.gov (United States)

    Whitfield, Lloyd R; Porcari, Anthony R; Alvey, Christine; Abel, Robert; Bullen, William; Hartman, Daniel

    2011-03-01

    Coadministration of statins and fibrates is beneficial in some patients by allowing simultaneous reduction of triglycerides and low-density lipoprotein cholesterol alongside elevation of high-density lipoprotein cholesterol. However, the potential for drug interactions must be taken into consideration. Gemfibrozil increases systemic exposure to various different statins, whereas similar effects are not observed with fenofibrate, suggesting it may be a more appropriate choice for coadministration with statins. Gemfibrozil is reported to cause a moderate increase in the area under the curve (AUC) of atorvastatin, but the effect of fenofibrate on atorvastatin pharmacokinetics has not been described. This study compared the effects of multiple-dose administration of gemfibrozil and fenofibrate on the single-dose pharmacokinetics of atorvastatin. Gemfibrozil coadministration led to significant increases in the AUC of atorvastatin, 2-hydroxyatorvastatin, 2-hydroxyatorvastatin lactone, and 4-hydroxyatorvastatin lactone. In contrast, fenofibrate administration did not lead to clinically meaningful changes in the AUC for atorvastatin, atorvastatin lactone, 2-hydroxyatorvastatin, or 2-hydroxyatorvastatin lactone. The absence of a significant pharmacokinetic interaction between fenofibrate and atorvastatin is consistent with recent results showing no difference in safety profile between atorvastatin as monotherapy or in combination with fenofibric acid. Together, these data suggest that atorvastatin-fenofibrate combination therapy is unlikely to pose a risk to patients.

  1. Chiral Pesticide Pharmacokinetics: A Range of Values

    Science.gov (United States)

    Approximately 30% of pesticides are chiral and used as mixtures of two or more stereoisomers. In biological systems, these stereoisomers can exhibit significantly different pharmacokinetics (absorption, distribution, metabolism, and elimination). In spite of these differences, th...

  2. Combining modularity, conservation, and interactions of proteins significantly increases precision and coverage of protein function prediction

    Directory of Open Access Journals (Sweden)

    Sers Christine T

    2010-12-01

    Full Text Available Abstract Background While the number of newly sequenced genomes and genes is constantly increasing, elucidation of their function still is a laborious and time-consuming task. This has led to the development of a wide range of methods for predicting protein functions in silico. We report on a new method that predicts function based on a combination of information about protein interactions, orthology, and the conservation of protein networks in different species. Results We show that aggregation of these independent sources of evidence leads to a drastic increase in number and quality of predictions when compared to baselines and other methods reported in the literature. For instance, our method generates more than 12,000 novel protein functions for human with an estimated precision of ~76%, among which are 7,500 new functional annotations for 1,973 human proteins that previously had zero or only one function annotated. We also verified our predictions on a set of genes that play an important role in colorectal cancer (MLH1, PMS2, EPHB4 and could confirm more than 73% of them based on evidence in the literature. Conclusions The combination of different methods into a single, comprehensive prediction method infers thousands of protein functions for every species included in the analysis at varying, yet always high levels of precision and very good coverage.

  3. Significance of structure–soil–structure interaction for closely spaced structures

    International Nuclear Information System (INIS)

    Roy, Christine; Bolourchi, Said; Eggers, Daniel

    2015-01-01

    Nuclear facilities typically consist of many closely spaced structures with different sizes and depths of embedment. Seismic response of each structure could be influenced by dynamic structure–soil–structure interaction (SSSI) behavior of adjacent closely spaced structures. This paper examines the impact of SSSI on the in-structure response spectra (ISRS) and peak accelerations of a light structure adjacent to a heavy structure and of a heavy structure adjacent to a similar heavy structure for several soil cases, foundation embedment depths, and separation distances. The impacts of a heavy surface or embedded structure on adjacent ground motions were studied. The analyses demonstrated the adjacent ground motions are sensitive to foundation embedment, soil profile, response frequency, and distance from the structure. Seismic responses of a light structure located near a heavy structure are calculated either by modeling both structures subjected to free field motions, or performing a cascade analysis by considering the light structure model subjected to modified ground motions due to the heavy structure. Cascade SSSI analyses are shown to adequately account for the effect of the heavy structure on the light structure without explicitly modeling both structures together in a single analysis. To further study the influence of SSSI behavior, this paper examines dynamic response of two adjacent heavy structures and compares this response to response of a single heavy structure neglecting adjacent structures. The SSSI responses of the two heavy structures are evaluated for varying soil conditions and structure separation distances using three-dimensional linear SSI analyses and considering anti-symmetry boundary conditions. The analyses demonstrate that the SSSI response of a light or a heavy structure can be influenced by the presence of a nearby heavy structure. Although this study considers linear analysis methodology, the conclusion of SSSI influences on dynamic

  4. Significance of foundation-soil separation in dynamic soil-structure interaction

    Science.gov (United States)

    Spyrakos, Constantine C.; Patel, P. N.

    1987-01-01

    THe dynamic response of flexible surface strip-foundations allowed to uplift is numerically obtained for externally applied forces of a transient time variation. The soil medium is represented by an isotropic, homogeneous and linear half-space. The soil is treated by a time domain boundary element method, while the flexible foundation is treated by the finite element method. It was concluded that intermediate relative stiffness leads to moderate deformations when uplift is permitted. Very flexible footings produce higher deformations in unilateral contact compared to bilateral contact, and thus should be considered in their design. Unilateral contact does not significantly increase deformations for stiff footings subjected to concentrated central loading. However, relatively large deformation differences occur when the loading is eccentric, necessitating consideration of uplift in their design.

  5. Significance of Microbial Communities and Interactions in Safeguarding Reactive Mine Tailings by Ecological Engineering▿†

    Science.gov (United States)

    N̆ancucheo, Ivan; Johnson, D. Barrie

    2011-01-01

    Pyritic mine tailings (mineral waste generated by metal mining) pose significant risk to the environment as point sources of acidic, metal-rich effluents (acid mine drainage [AMD]). While the accelerated oxidative dissolution of pyrite and other sulfide minerals in tailings by acidophilic chemolithotrophic prokaryotes has been widely reported, other acidophiles (heterotrophic bacteria that catalyze the dissimilatory reduction of iron and sulfur) can reverse the reactions involved in AMD genesis, and these have been implicated in the “natural attenuation” of mine waters. We have investigated whether by manipulating microbial communities in tailings (inoculating with iron- and sulfur-reducing acidophilic bacteria and phototrophic acidophilic microalgae) it is possible to mitigate the impact of the acid-generating and metal-mobilizing chemolithotrophic prokaryotes that are indigenous to tailing deposits. Sixty tailings mesocosms were set up, using five different microbial inoculation variants, and analyzed at regular intervals for changes in physicochemical and microbiological parameters for up to 1 year. Differences between treatment protocols were most apparent between tailings that had been inoculated with acidophilic algae in addition to aerobic and anaerobic heterotrophic bacteria and those that had been inoculated with only pyrite-oxidizing chemolithotrophs; these differences included higher pH values, lower redox potentials, and smaller concentrations of soluble copper and zinc. The results suggest that empirical ecological engineering of tailing lagoons to promote the growth and activities of iron- and sulfate-reducing bacteria could minimize their risk of AMD production and that the heterotrophic populations could be sustained by facilitating the growth of microalgae to provide continuous inputs of organic carbon. PMID:21965397

  6. Effect of gemfibrozil on the pharmacokinetics of mitiglinide in rats.

    Science.gov (United States)

    Jin, L; Cao, Q

    2012-01-01

    A sensitive and specific method was developed and validated for the determination of mitiglinide in plasma using LC-MS/MS. The effect of gemfibrozil on the pharmacokinetics of orally administered mitiglinide in rats was investigated. The validated method in positive electrospray ionization mode using MRM and fully validated according to commonly accepted criteria. The desired sensitivity of mitiglinide was achieved with an LOQ of 0.5 ng/mL and the short run time was suitable for analysis of the large batches of samples. The method was successfully used to analyze rats plasma samples for application in pharmacokinetic studies. Pharmacokinetic parameters of mitiglinide were determined in rats following oral (0.25, 0.5, 1 mg/kg) administration to rats in the presence and absence of gemfibrozil (1 mg/kg). Compared to those animals in an oral control group (given mitiglinide alone), the area under the plasma concentration-time curve (AUC) of mitiglinide were increased significantly by 2.8, 3.5, 4.1-fold (0.25, 0.5, 1 mg/kg) by gemfibrozil, respectively. Consequently, the bioavailability of mitiglinide in the presence of gemfibrozil was significantly enhanced compared to that in oral control group (only mitiglinide). Gemfibrozil significantly enhanced the oral bioavailability of mitiglinide, suggesting that concurrent use of gemfibrozil and mitiglinide should be monitored closely for potential drug interactions. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Insights into significant pathways and gene interaction networks in peripheral blood mononuclear cells for early diagnosis of hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    Jian Xin Jiang

    2016-01-01

    Conclusions: Using identified DEGs, significantly changed biological processes such as nucleic acid metabolic process and KEGG pathways such as cytokine-cytokine receptor interaction in PBMCs of HCC patients were identified. In addition, several important hub genes, for example, CUL4A, and interleukin (IL 8 were also uncovered.

  8. Metabolic Pathway of Icotinib In Vitro: The Differential Roles of CYP3A4, CYP3A5, and CYP1A2 on Potential Pharmacokinetic Drug-Drug Interaction.

    Science.gov (United States)

    Zhang, TianHong; Zhang, KeRong; Ma, Li; Li, Zheng; Wang, Juan; Zhang, YunXia; Lu, Chuang; Zhu, Mingshe; Zhuang, XiaoMei

    2018-04-01

    Icotinib is the first self-developed small molecule drug in China for targeted therapy of non-small cell lung cancer. To date, systematic studies on the pharmacokinetic drug-drug interaction of icotinib were limited. By identifying metabolite generated in human liver microsomes and revealing the contributions of major cytochromes P450 (CYPs) in the formation of major metabolites, the aim of the present work was to understand the mechanisms underlying pharmacokinetic and pharmacological variability in clinic. A liquid chromatography/UV/high-resolution mass spectrometer method was developed to characterize the icotinib metabolites. The formation of 6 major metabolites was studied in recombinant CYP isozymes and human liver microsomes with specific inhibitors to identify the CYPs responsible for icotinib metabolism. The metabolic pathways observed in vitro are consistent with those observed in human. Results demonstrated that the metabolites are predominantly catalyzed by CYP3A4 (77%∼87%), with a moderate contribution from CYP3A5 (5%∼15%) and CYP1A2 (3.7%∼7.5%). The contribution of CYP2C8, 2C9, 2C19, and 2D6 is insignificant. Based on our observations, to minimize drug-drug interaction risk in clinic, coprescription of icotinib with strong CYP3A inhibitors or inducers must be weighed. CYP1A2, a highly inducible enzyme in the smoking population, may also represent a determinant of pharmacokinetic and pharmacological variability of icotinib, especially in lung cancer patients with smoking history. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  9. Population Pharmacokinetics of Intranasal Scopolamine

    Science.gov (United States)

    Wu, L.; Chow, D. S. L.; Putcha, L.

    2013-01-01

    Introduction: An intranasal gel dosage formulation of scopolamine (INSCOP) was developed for the treatment of Space Motion Sickness (SMS).The bioavailability and pharmacokinetics (PK) was evaluated using data collected in Phase II IND protocols. We reported earlier statistically significant gender differences in PK parameters of INSCOP at a dose level of 0.4 mg. To identify covariates that influence PK parameters of INSCOP, we examined population covariates of INSCOP PK model for 0.4 mg dose. Methods: Plasma scopolamine concentrations versus time data were collected from 20 normal healthy human subjects (11 male/9 female) after a 0.4 mg dose. Phoenix NLME was employed for PK analysis of these data using gender, body weight and age as covariates for model selection. Model selection was based on a likelihood ratio test on the difference of criteria (-2LL). Statistical significance for base model building and individual covariate analysis was set at P less than 0.05{delta(-2LL)=3.84}. Results: A one-compartment pharmacokinetic model with first-order elimination best described INSCOP concentration ]time profiles. Inclusion of gender, body weight and age as covariates individually significantly reduced -2LL by the cut-off value of 3.84(P less than 0.05) when tested against the base model. After the forward stepwise selection and backward elimination steps, gender was selected to add to the final model which had significant influence on absorption rate constant (ka) and the volume of distribution (V) of INSCOP. Conclusion: A population pharmacokinetic model for INSCOP has been identified and gender was a significant contributing covariate for the final model. The volume of distribution and Ka were significantly higher in males than in females which confirm gender-dependent pharmacokinetics of scopolamine after administration of a 0.4 mg dose.

  10. Clinically significant drug–drug interactions involving opioid analgesics used for pain treatment in patients with cancer: a systematic review

    Directory of Open Access Journals (Sweden)

    Kotlinska-Lemieszek A

    2015-09-01

    Full Text Available Aleksandra Kotlinska-Lemieszek,1 Pål Klepstad,2,3,6 Dagny Faksvåg Haugen2,4,5 1Palliative Medicine Chair and Department, University Hospital of the Lord’s Transfiguration, Karol Marcinkowski University of Medical Sciences, Poznan, Poland; 2European Palliative Care Research Centre, Faculty of Medicine, Norwegian University of Science and Technology,Trondheim, Norway; 3Department of Anaesthesiology and Intensive Care Medicine, St Olavs Hospital, Trondheim, Norway; 4Regional Centre of Excellence for Palliative Care, Haukeland University Hospital, Bergen, Norway; 5Department of Clinical Medicine K1, University of Bergen, Bergen, Norway; 6Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway Background: Opioids are the most frequently used drugs to treat pain in cancer patients. In some patients, however, opioids can cause adverse effects and drug–drug interactions. No advice concerning the combination of opioids and other drugs is given in the current European guidelines. Objective: To identify studies that report clinically significant drug–drug interactions involving opioids used for pain treatment in adult cancer patients. Design and data sources: Systematic review with searches in Embase, MEDLINE, and Cochrane Central Register of Controlled Trials from the start of the databases (Embase from 1980 through January 2014. In addition, reference lists of relevant full-text papers were hand-searched. Results: Of 901 retrieved papers, 112 were considered as potentially eligible. After full-text reading, 17 were included in the final analysis, together with 15 papers identified through hand-searching of reference lists. All of the 32 included publications were case reports or case series. Clinical manifestations of drug–drug interactions involving opioids were grouped as follows: 1 sedation and respiratory depression, 2 other central nervous system symptoms, 3 impairment of pain

  11. GxE Interactions Between FOXO Genotypes and Tea Drinking Significantly Affect Cognitive Disability at Advanced Ages in China

    DEFF Research Database (Denmark)

    Zeng, Yi; Chen, Huashuai; Ni, Ting

    2015-01-01

    Logistic regression analysis based on data from 822 Han Chinese oldest old aged 92+ demonstrated that interactions between carrying FOXO1A-266 or FOXO3-310 or FOXO3-292 and tea drinking at around age 60 or at present time were significantly associated with lower risk of cognitive disability...... at advanced ages. Associations between tea drinking and reduced cognitive disability were much stronger among carriers of the genotypes of FOXO1A-266 or FOXO3-310 or FOXO3-292 compared with noncarriers, and it was reconfirmed by analysis of three-way interactions across FOXO genotypes, tea drinking at around...... age 60, and at present time. Based on prior findings from animal and human cell models, we postulate that intake of tea compounds may activate FOXO gene expression, which in turn may positively affect cognitive function in the oldest old population. Our empirical findings imply that the health...

  12. Modelling delays in pharmacokinetics

    International Nuclear Information System (INIS)

    Farooqi, Z.H.; Lambrecht, R.M.

    1990-01-01

    Linear system analysis has come to form the backbone of pharmacokinetics. Natural systems usually involve time delays, thus models incorporating them would be an order closer approximation to the real world compared to those that do not. Delays may be modelled in several ways. The approach considered in this study is to have a discrete-time delay dependent rate with the delay respresenting the duration between the entry of a drug into a compartment and its release in some form (may be as a metabolite) from the compartment. Such a delay may be because of one or more of several physiological reasons, like, formation of a reservoir, slow metabolism, or receptor binding. The mathematical structure this gives rise to is a system of delay-differential equations. Examples are given of simple one and two compartment systems with drugs like bumetanide, carbamazepine, and quinolone-caffeine interaction. In these examples generally a good fit is obtained and the suggested models form a good approximation. 21 refs., 6 figs

  13. Interaction between FOXO1A-209 Genotype and Tea Drinking is Significantly Associated with Reduced Mortality at Advanced Ages

    DEFF Research Database (Denmark)

    Zeng, Yi; Chen, Huashuai; Ni, Ting

    2016-01-01

    Based on the genotypic/phenotypic data from Chinese Longitudinal Healthy Longevity Survey (CLHLS) and Cox proportional hazard model, the present study demonstrates that interactions between carrying FOXO1A-209 genotypes and tea drinking are significantly associated with lower risk of mortality...... at advanced ages. Such significant association is replicated in two independent Han Chinese CLHLS cohorts (p =0.028-0.048 in the discovery and replication cohorts, and p =0.003-0.016 in the combined dataset). We found the associations between tea drinking and reduced mortality are much stronger among carriers...... of the FOXO1A-209 genotype compared to non-carriers, and drinking tea is associated with a reversal of the negative effects of carrying FOXO1A-209 minor alleles, that is, from a substantially increased mortality risk to substantially reduced mortality risk at advanced ages. The impacts are considerably...

  14. Personalized therapeutics for levofloxacin: a focus on pharmacokinetic concerns.

    Science.gov (United States)

    Gao, Chu-Han; Yu, Lu-Shan; Zeng, Su; Huang, Yu-Wen; Zhou, Quan

    2014-01-01

    associated with sample size and administration route. Children younger than 5 years cleared LVX nearly twice as fast as adults. Patients in intensive care receiving LVX therapy showed significant pharmacokinetic differences compared with healthy subjects. Creatinine clearance explained most of the population variance in the plasma clearance of LVX. Switching from intravenous to oral delivery of LVX had economic benefits. Addition of tamsulosin to the LVX regimen was beneficial for patients with bacterial prostatitis because tamsulosin could increase the maximal concentration of LVX in prostatic tissue. Coadministration of multivalent cation-containing drugs and LVX should be avoided. For patients receiving warfarin and LVX concomitantly, caution is needed regarding potential changes in the international normalized ratio; however, it is unnecessary to seek alternatives to LVX for the sake of avoiding drug interaction with warfarin. It is unnecessary to proactively reduce the dose of cyclosporin or tacrolimus when comedicated with LVX. Transporters such as organic anion-transporting polypeptide 1A2, P-glycoprotein, human organic cation transporter 1, and multidrug and toxin extrusion protein 1 are involved in the pharmacokinetics of LVX. Personalized LVX therapeutics are necessary for the sake of better safety, clinical success, and avoidance of resistance. New findings regarding individual dosing of LVX in special patient populations and active transport mechanisms in vivo are opening up new horizons in clinical practice.

  15. Pharmacokinetics of Snake Venom

    OpenAIRE

    Suchaya Sanhajariya; Stephen B. Duffull; Geoffrey K. Isbister

    2018-01-01

    Understanding snake venom pharmacokinetics is essential for developing risk assessment strategies and determining the optimal dose and timing of antivenom required to bind all venom in snakebite patients. This review aims to explore the current knowledge of snake venom pharmacokinetics in animals and humans. Literature searches were conducted using EMBASE (1974–present) and Medline (1946–present). For animals, 12 out of 520 initially identified studies met the inclusion criteria. In general, ...

  16. [Research progress on current pharmacokinetic evaluation of Chinese herbal medicines].

    Science.gov (United States)

    Li, Guofu; Zhao, Haoru; Yang, Jin

    2011-03-01

    In order to prove safety and efficacy, herbal medicines must undergo the rigorous scientific researches such as pharmacokinetic and bioavailability, before they are put on the market in the foreign countries. Botanical Drug Products promulgated by the US FDA could guide industry sponsors to develop herbal drugs, which was also an important reference for investigating Chinese herbal medicines. This paper reviews and discusses novel approaches for how to assess systemic exposure and pharmacokinetic of Chinese herbal medicines, which were in line with FDA guidance. This mainly focus on identifying pharmacokinetic markers of botanical products, integral pharmacokinetic study of multiple components, Biopharmaceutics drug disposition classification system, and population pharmacokinetic-pharmacodynamic study in herb-drug interaction.

  17. Assortative and dissortative priorities for game interaction and strategy adaptation significantly bolster network reciprocity in the prisoner’s dilemma

    International Nuclear Information System (INIS)

    Tanimoto, Jun

    2014-01-01

    In 2 × 2 prisoner’s dilemma games, network reciprocity is one mechanism for adding social viscosity, which leads to cooperative equilibrium. Here we show that combining the process for selecting a gaming partner with the process for selecting an adaptation partner significantly enhances cooperation, even though such selection processes require additional costs to collect further information concerning which neighbor should be chosen. Based on elaborate investigations of the dynamics generated by our model, we find that high levels of cooperation result from two kinds of behavior: cooperators tend to interact with cooperators to prevent being exploited by defectors and defectors tend to choose cooperators to exploit despite the possibility that some defectors convert to cooperators. (paper)

  18. Biological significance of facilitated diffusion in protein-DNA interactions. Applications to T4 endonuclease V-initiated DNA repair

    International Nuclear Information System (INIS)

    Dowd, D.R.; Lloyd, R.S.

    1990-01-01

    Facilitated diffusion along nontarget DNA is employed by numerous DNA-interactive proteins to locate specific targets. Until now, the biological significance of DNA scanning has remained elusive. T4 endonuclease V is a DNA repair enzyme which scans nontarget DNA and processively incises DNA at the site of pyrimidine dimers which are produced by exposure to ultraviolet (UV) light. In this study we tested the hypothesis that there exists a direct correlation between the degree of processivity of wild type and mutant endonuclease V molecules and the degree of enhanced UV resistance which is conferred to repair-deficient Eshcerichia coli. This was accomplished by first creating a series of endonuclease V mutants whose in vitro catalytic activities were shown to be very similar to that of the wild type enzyme. However, when the mechanisms by which these enzymes search nontarget DNA for its substrate were analyzed in vitro and in vivo, the mutants displayed varying degrees of nontarget DNA scanning ranging from being nearly as processive as wild type to randomly incising dimers within the DNA population. The ability of these altered endonuclease V molecules to enhance UV survival in DNA repair-deficient E. coli then was assessed. The degree of enhanced UV survival was directly correlated with the level of facilitated diffusion. This is the first conclusive evidence directly relating a reduction of in vivo facilitated diffusion with a change in an observed phenotype. These results support the assertion that the mechanisms which DNA-interactive proteins employ in locating their target sites are of biological significance

  19. [Pharmacokinetics of digoxin in hyperthyroidism. Effect of methimazole].

    Science.gov (United States)

    Izbicka, Maria; Gasińska, Teresa; Dec, Renata

    2010-01-01

    Cardiovascular abnormalities may be the only manifestations of overt hyperthyroidism. In patients with heart failure and atrial fibrillation digoxin can be beneficial in controlling the symptoms and signs, but hyperthyroid patients show an impaired response or even resistance to digoxin treatment. The aim of the study is to establish: 1. Are there any differences in the pharmacokinetics of a single oral dose of digoxin between hypertyroid and euthyroid patients? 2. Does simultaneous administration of digoxin and methimazole affect the pharmacokinetics of a single oral dose of dogoxin? 3. Does methimazole-induced euthyroidism change the pharmacokinetics of a single oral dose of digoxin? The subject of the study were 28 patients with hyperthyroidism and 15 healthy persons. We evaluated the pharmacokinetics of a single oral dose of digoxin. Moreover we evaluated pharmacokinetics of a single dose of digoxin after simultaneous administration of digoxin and methimazole in 12 patients and 12 methimazole treated patients werere-assessed once they had become euthyroid. Hyperthyroid patients showed significantly lower serum digoxin concentrations, shorter T1/2 beta and a significantly smaller area under the concentration curve (AUC) that the control group. Administration of methimazole did not affect digoxin pharmacokinetics. In hyperthyroid patients: 1. the pharmacokinetics of a single oral dose of digoxin does differ from that observed in healthy subjects. 2.methimazole do not alter digoxin pharmacokinetics.

  20. UNCERTAINTIES IN TRICHLOROETHYLENE PHARMACOKINETIC MODELS

    Science.gov (United States)

    Understanding the pharmacokinetics of a chemical¯its absorption, distribution, metabolism, and excretion in humans and laboratory animals ¯ is critical to the assessment of its human health risks. For trichloroethylene (TCE), numerous physiologically-based pharmacokinetic (PBPK)...

  1. Interactive cervical motion kinematics: sensitivity, specificity and clinically significant values for identifying kinematic impairments in patients with chronic neck pain.

    Science.gov (United States)

    Sarig Bahat, Hilla; Chen, Xiaoqi; Reznik, David; Kodesh, Einat; Treleaven, Julia

    2015-04-01

    Chronic neck pain has been consistently shown to be associated with impaired kinematic control including reduced range, velocity and smoothness of cervical motion, that seem relevant to daily function as in quick neck motion in response to surrounding stimuli. The objectives of this study were: to compare interactive cervical kinematics in patients with neck pain and controls; to explore the new measures of cervical motion accuracy; and to find the sensitivity, specificity, and optimal cutoff values for defining impaired kinematics in those with neck pain. In this cross-section study, 33 patients with chronic neck pain and 22 asymptomatic controls were assessed for their cervical kinematic control using interactive virtual reality hardware and customized software utilizing a head mounted display with built-in head tracking. Outcome measures included peak and mean velocity, smoothness (represented by number of velocity peaks (NVP)), symmetry (represented by time to peak velocity percentage (TTPP)), and accuracy of cervical motion. Results demonstrated significant and strong effect-size differences in peak and mean velocities, NVP and TTPP in all directions excluding TTPP in left rotation, and good effect-size group differences in 5/8 accuracy measures. Regression results emphasized the high clinical value of neck motion velocity, with very high sensitivity and specificity (85%-100%), followed by motion smoothness, symmetry and accuracy. These finding suggest cervical kinematics should be evaluated clinically, and screened by the provided cut off values for identification of relevant impairments in those with neck pain. Such identification of presence or absence of kinematic impairments may direct treatment strategies and additional evaluation when needed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Pharmacokinetics and pharmacodynamics of diclofenac in the presence and absence of glibenclamide in the rat.

    Science.gov (United States)

    León-Reyes, María R; Castañeda-Hernández, Gilberto; Ortiz, Mario I

    2008-01-01

    There are evidences that glibenclamide, a sulfonylurea antidiabetic agent, reduces the analgesic action of non-steroidal antiinflammatory drugs (NSAIDs), opioids and neuromodulators in animal models. The purpose of this work was to examine in the rat if such interaction involves pharmacokinetic mechanisms or is solely limited to the pharmacodynamic level. All studies were carried out in female Wistar rats. Analgesia was assessed using the formalin test. Fifty microliters of diluted formalin was injected subcutaneously into the dorsal surface of the right hind paw. Nociceptive behavior was quantified as the number of flinches of the injected paw during 60 min after injection and a reduction in formalin-induced flinching was interpreted as an analgesic response. Rats were treated with oral diclofenac (3-18 mg/kg) in presence and the absence of oral glibenclamide (1-30 mg/kg). To evaluate the possibility of a pharmacokinetic interaction, the oral bioavailability of diclofenac (18 mg/kg) was studied in presence and the absence of glibenclamide (10 mg/kg). Oral administration of diclofenac produced a dose-dependent antinociceptive effect in the formalin test. Coadministration of glibenclamide significantly reduced diclofenac-induced antinociception. Notwithstanding, the interaction does no appear to involve pharmacokinetic mechanisms, as oral glibenclamide failed to produce any significant alteration in oral diclofenac bioavailability. Concomitant systemic administration of glibenclamide and diclofenac results in a reduction of the analgesic effect of the NSAID in the formalin test in the rat. This interaction, however, appears due solely to a pharmacodynamic mechanisms as diclofenac pharmacokinetics are not altered.

  3. Pharmacokinetics, pharmacodynamics and toxicology of theranostic nanoparticles

    Science.gov (United States)

    Kang, Homan; Mintri, Shrutika; Menon, Archita Venugopal; Lee, Hea Yeon; Choi, Hak Soo; Kim, Jonghan

    2015-11-01

    Nanoparticles (NPs) are considered a promising tool in both diagnosis and therapeutics. Theranostic NPs possess the combined properties of targeted imaging and drug delivery within a single entity. While the categorization of theranostic NPs is based on their structure and composition, the pharmacokinetics of NPs are significantly influenced by the physicochemical properties of theranostic NPs as well as the routes of administration. Consequently, altered pharmacokinetics modify the pharmacodynamic efficacy and toxicity of NPs. Although theranostic NPs hold great promise in nanomedicine and biomedical applications, a lack of understanding persists on the mechanisms of the biodistribution and adverse effects of NPs. To better understand the diagnostic and therapeutic functions of NPs, this review discusses the factors that influence the pharmacokinetics, pharmacodynamics and toxicology of theranostic NPs, along with several strategies for developing novel diagnostic and therapeutic modalities.

  4. The Significance of Microbe-Mineral-Biomarker Interactions in the Detection of Life on Mars and Beyond.

    Science.gov (United States)

    Röling, Wilfred F M; Aerts, Joost W; Patty, C H Lucas; ten Kate, Inge Loes; Ehrenfreund, Pascale; Direito, Susana O L

    2015-06-01

    The detection of biomarkers plays a central role in our effort to establish whether there is, or was, life beyond Earth. In this review, we address the importance of considering mineralogy in relation to the selection of locations and biomarker detection methodologies with characteristics most promising for exploration. We review relevant mineral-biomarker and mineral-microbe interactions. The local mineralogy on a particular planet reflects its past and current environmental conditions and allows a habitability assessment by comparison with life under extreme conditions on Earth. The type of mineral significantly influences the potential abundances and types of biomarkers and microorganisms containing these biomarkers. The strong adsorptive power of some minerals aids in the preservation of biomarkers and may have been important in the origin of life. On the other hand, this strong adsorption as well as oxidizing properties of minerals can interfere with efficient extraction and detection of biomarkers. Differences in mechanisms of adsorption and in properties of minerals and biomarkers suggest that it will be difficult to design a single extraction procedure for a wide range of biomarkers. While on Mars samples can be used for direct detection of biomarkers such as nucleic acids, amino acids, and lipids, on other planetary bodies remote spectrometric detection of biosignatures has to be relied upon. The interpretation of spectral signatures of photosynthesis can also be affected by local mineralogy. We identify current gaps in our knowledge and indicate how they may be filled to improve the chances of detecting biomarkers on Mars and beyond.

  5. Clinical pharmacokinetics of melatonin

    DEFF Research Database (Denmark)

    Harpsøe, Nathja Groth; Andersen, Lars Peter Holst; Gögenur, Ismail

    2015-01-01

    was performed in PubMed and Embase databases. The pharmacokinetic variables included maximal plasma/serum concentration (Cmax), time to maximal plasma/serum concentration (Tmax), elimination half-life (T1/2), area-under-the-curve plasma/serum concentrations (AUC), clearance (Cl), volume of distribution (VD......) and 1602 L (4 mg, oral). Bioavailability of oral melatonin ranged from 9 to 33%. Pharmacokinetics was affected by age, caffeine, smoking, oral contraceptives, feeding status, and fluvoxamine. Critically ill patients displayed accelerated absorption and compromised elimination. CONCLUSIONS: Despite...

  6. Effect of fluoxetine on the pharmacokinetics of lansoprazole: a two-treatment period study in healthy male subjects.

    Science.gov (United States)

    Vlase, Laurian; Popa, Adina; Neag, Maria; Muntean, Dana; Leucuta, Sorin E

    2011-10-01

    Fluoxetine is an inhibitor of the main metabolizing enzymes of lansoprazole and could influence the pharmacokinetics of lansoprazole. The changes in lansoprazole pharmacokinetics could have clinical significance concerning the safety of the therapy. The aim of this study was to evaluate the pharmacokinetic interaction between fluoxetine and lansoprazole in healthy subjects. A dose of lansoprazole 30 mg, alone or in combination with fluoxetine 60 mg, was administered to 18 healthy male subjects in a two-treatment study design, separated by an 8-day period in which fluoxetine alone was administered as a single oral daily dose. Plasma concentrations of lansoprazole were determined during a 12-hour period following drug administration. Lansoprazole plasma concentrations were determined by a validated liquid chromatography-mass spectrometry method. The pharmacokinetic parameters of lansoprazole were calculated using non-compartmental analysis. In the two periods of treatment, the mean maximum plasma concentration (C(max)) values were 817 ng/mL (lansoprazole alone) and 1370 ng/mL (lansoprazole in combination with fluoxetine after pre-treatment with fluoxetine for 8 days) [p lansoprazole and suggest that the observed interaction may be clinically significant, although its clinical relevance has yet to be confirmed.

  7. Relative contributions of the major human CYP450 to the metabolism of icotinib and its implication in prediction of drug-drug interaction between icotinib and CYP3A4 inhibitors/inducers using physiologically based pharmacokinetic modeling.

    Science.gov (United States)

    Chen, Jia; Liu, Dongyang; Zheng, Xin; Zhao, Qian; Jiang, Ji; Hu, Pei

    2015-06-01

    Icotinib is an anticancer drug, but relative contributions of CYP450 have not been identified. This study was carried out to identify the contribution percentage of CYP450 to icotinib and use the results to develop a physiologically based pharmacokinetic (PBPK) model, which can help to predict drug-drug interaction (DDI). Human liver microsome (HLM) and supersome using relative activity factor (RAF) were employed to determine the relative contributions of the major human P450 to the net hepatic metabolism of icotinib. These values were introduced to develop a PBPK model using SimCYP. The model was validated by the observed data in a Phase I clinical trial in Chinese healthy subjects. Finally, the model was used to simulate the DDI with ketoconazole or rifampin. Final contribution of CYP450 isoforms determined by HLM showed that CYP3A4 provided major contributions to the metabolism of icotinib. The percentage contributions of the P450 to the net hepatic metabolism of icotinib were determined by HLM inhibition assay and RAF. The AUC ratio under concomitant use of ketoconazole and rifampin was 3.22 and 0.55, respectively. Percentage of contribution of CYP450 to icotinib metabolism was calculated by RAF. The model has been proven to fit the observed data and is used in predicting icotinib-ketoconazole/rifampin interaction.

  8. Circadian variation in the pharmacokinetics of verapamil

    DEFF Research Database (Denmark)

    Jespersen, C M; Frederiksen, M; Hansen, J F

    1989-01-01

    greater bioavailability (AUC) and a prolonged time to peak concentration was found. During the night (24.00 h-06.00 h) the half-life of verapamil was significantly longer than during the day (16.00 h-22.00 h). These differences in pharmacokinetics may be due to reduced hepatic blood flow at night...

  9. Effect of tramadol on metamizol pharmacokinetics and pharmacodynamics after single and repeated administrations in arthritic rats

    Directory of Open Access Journals (Sweden)

    Luis Alfonso Moreno-Rocha

    2016-11-01

    Full Text Available Combined administration of certain doses of opioid compounds with a non-steroidal anti-inflammatory drug can produce additive or supra-additive effects while reducing unwanted effects. We have recently reported that co-administration of metamizol with tramadol produces antinociceptive effect potentiation, after acute treatment. However, none information about the effect produced by the combination after chronic or repeated dose administration exists. The aims of this study were to investigate whether the antinociceptive synergism produced by the combination of metamizol and tramadol (177.8 + 17.8 mg/kg, s.c. respectively is maintained after repeated treatment and whether the effects observed are primarily due to pharmacodynamic interactions or may be related to pharmacokinetics changes. Administration of metamizol plus tramadol acute treatment significantly enhanced the antinociceptive effect of the drugs given alone (P  0.05. The mechanism involved in the synergism of the antinociceptive effect observed with the combination of metamizol and tramadol in single dose cannot be attributed to a pharmacokinetic interaction, and other pharmacodynamic interactions have to be considered. On the other hand, when metamizol and tramadol were co-administered under repeated administrations, a pharmacokinetic interaction and tolerance development occurred. Differences found in metamizol active metabolites’ pharmacokinetics (P < 0.05 were related to the development of tolerance produced by the combination after repeated doses. This work shows an additional preclinical support for the combination therapy. The clinical utility of this combination in a suitable dose range should be evaluated in future studies.

  10. Pharmacokinetics of Melatonin

    DEFF Research Database (Denmark)

    Andersen, Lars Peter Holst; Gögenur, Ismail; Rosenberg, Jacob

    2016-01-01

    Despite widespread clinical application of melatonin, several unanswered questions remain regarding the pharmacokinetics of this drug. This lack of knowledge may contribute to the inconsistency of results in previous clinical studies. Currently, a t max value of 30-45 min and a t ½elimination of ...

  11. Pharmacokinetic evaluation of pemetrexed

    DEFF Research Database (Denmark)

    Sørensen, Jens Benn

    2011-01-01

    correlates with renal function and it may be safely used with vitamin supplementation in patients with creatinine clearance ≥ 45 ml/min. The pharmacokinetics of pemetrexed is also largely unchanged in third-space fluids and can be feasibly and safely administered in combination with several other cytotoxic...

  12. Pharmacokinetic evaluation of pemetrexed

    DEFF Research Database (Denmark)

    Sørensen, Jens Benn

    2011-01-01

    correlates with renal function and it may be safely used with vitamin supplementation in patients with creatinine clearance = 45 ml/min. The pharmacokinetics of pemetrexed is also largely unchanged in third-space fluids and can be feasibly and safely administered in combination with several other cytotoxic...

  13. Personalized therapeutics for levofloxacin: a focus on pharmacokinetic concerns

    Directory of Open Access Journals (Sweden)

    Gao CH

    2014-03-01

    more efficiently than normal-weight individuals. Compared with the scenario in healthy subjects, standard 2-hour spacing of calcium formulations and oral LVX was insufficient to prevent a chelation interaction in cystic fibrosis patients. Inconsistent conclusions were derived from studies of the influence of sex on the pharmacokinetics of LVX, which might be associated with sample size and administration route. Children younger than 5 years cleared LVX nearly twice as fast as adults. Patients in intensive care receiving LVX therapy showed significant pharmacokinetic differences compared with healthy subjects. Creatinine clearance explained most of the population variance in the plasma clearance of LVX. Switching from intravenous to oral delivery of LVX had economic benefits. Addition of tamsulosin to the LVX regimen was beneficial for patients with bacterial prostatitis because tamsulosin could increase the maximal concentration of LVX in prostatic tissue. Coadministration of multivalent cation-containing drugs and LVX should be avoided. For patients receiving warfarin and LVX concomitantly, caution is needed regarding potential changes in the international normalized ratio; however, it is unnecessary to seek alternatives to LVX for the sake of avoiding drug interaction with warfarin. It is unnecessary to proactively reduce the dose of cyclosporin or tacrolimus when comedicated with LVX. Transporters such as organic anion-transporting polypeptide 1A2, P-glycoprotein, human organic cation transporter 1, and multidrug and toxin extrusion protein 1 are involved in the pharmacokinetics of LVX.Conclusion: Personalized LVX therapeutics are necessary for the sake of better safety, clinical success, and avoidance of resistance. New findings regarding individual dosing of LVX in special patient populations and active transport mechanisms in vivo are opening up new horizons in clinical practice.Keywords: drug interactions, fluoroquinolone resistance, individual dosing, patient

  14. The pharmacokinetics and safety profile of oral ganciclovir in combination with trimethoprim in HIV- and CMV-seropositive patients

    Science.gov (United States)

    Jung, Donald; AbdelHameed, Magdy H; Hunter, John; Teitelbaum, Philip; Dorr, Albert; Griffy, Kay

    1999-01-01

    Aims We investigated the pharmacokinetics and safety profile of oral ganciclovir coadministered with trimethoprim in HIV-and CMV-seropositive patients. Methods In an open-label, randomized, 3-way crossover study, 12 adult males received oral ganciclovir 1000 mg every 8h, oral trimethoprim 200 mg once daily, or both drugs concomitantly in a sequence of three 7-day treatment periods. Pharmacokinetic parameters were determined and adverse events recorded for each treatment. Results The presence of trimethoprim significantly decreased CLr (12.9%, P = 0.0068) and increased t1/2 (18.1%, P = 0.0378) of ganciclovir. However, these changes are unlikely to be clinically meaningful. There were no statistically significant changes in trimethoprim pharmacokinetic parameters in the presence of ganciclovir, with the exception of a 12.7% increase in Cmin. Ganciclovir was well tolerated when administered alone or in combination with trimethoprim. Conclusions There was no clinically significant pharmacokinetic interaction between oral ganciclovir and trimethoprim when coadministered. PMID:10215748

  15. Quantitative Analysis of Complex Drug-Drug Interactions Between Repaglinide and Cyclosporin A/Gemfibrozil Using Physiologically Based Pharmacokinetic Models With In Vitro Transporter/Enzyme Inhibition Data.

    Science.gov (United States)

    Kim, Soo-Jin; Toshimoto, Kota; Yao, Yoshiaki; Yoshikado, Takashi; Sugiyama, Yuichi

    2017-09-01

    Quantitative analysis of transporter- and enzyme-mediated complex drug-drug interactions (DDIs) is challenging. Repaglinide (RPG) is transported into the liver by OATP1B1 and then is metabolized by CYP2C8 and CYP3A4. The purpose of this study was to describe the complex DDIs of RPG quantitatively based on unified physiologically based pharmacokinetic (PBPK) models using in vitro K i values for OATP1B1, CYP3A4, and CYP2C8. Cyclosporin A (CsA) or gemfibrozil (GEM) increased the blood concentrations of RPG. The time profiles of RPG and the inhibitors were analyzed by PBPK models, considering the inhibition of OATP1B1 and CYP3A4 by CsA or OATP1B1 inhibition by GEM and its glucuronide and the mechanism-based inhibition of CYP2C8 by GEM glucuronide. RPG-CsA interaction was closely predicted using a reported in vitro K i,OATP1B1 value in the presence of CsA preincubation. RPG-GEM interaction was underestimated compared with observed data, but the simulation was improved with the increase of f m,CYP2C8 . These results based on in vitro K i values for transport and metabolism suggest the possibility of a bottom-up approach with in vitro inhibition data for the prediction of complex DDIs using unified PBPK models and in vitro f m value of a substrate for multiple enzymes should be considered carefully for the prediction. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  16. Pharmacokinetics of metformin during pregnancy.

    Science.gov (United States)

    Eyal, Sara; Easterling, Thomas R; Carr, Darcy; Umans, Jason G; Miodovnik, Menachem; Hankins, Gary D V; Clark, Shannon M; Risler, Linda; Wang, Joanne; Kelly, Edward J; Shen, Danny D; Hebert, Mary F

    2010-05-01

    Our objective was to evaluate the pharmacokinetics of metformin during pregnancy. Serial blood and urine samples were collected over one steady-state dosing interval in women treated with metformin during early to late pregnancy (n = 35) and postpartum (n = 16). Maternal and umbilical cord blood samples were obtained at delivery from 12 women. Metformin concentrations were also determined in breast milk samples obtained over one dosing interval in 6 women. Metformin renal clearance increased significantly in mid (723 +/- 243 ml/min, P pregnancy (625 +/- 130 ml/min, P metformin net secretion clearance (480 +/- 190 ml/min, P pregnancy versus postpartum, respectively. Metformin concentrations at the time of delivery in umbilical cord plasma ranged between nondetectable (metformin through breast milk was 0.13 to 0.28 mg, and the relative infant dose was metformin pharmacokinetics are affected by pregnancy-related changes in renal filtration and net tubular transport and can be roughly estimated by the use of creatinine clearance. At the time of delivery, the fetus is exposed to metformin concentrations from negligible to as high as maternal concentrations. In contrast, infant exposure to metformin through the breast milk is low.

  17. Elementary electron-molecule interactions and negative ion resonances at subexcitation energies and their significance in gaseous dielectrics

    International Nuclear Information System (INIS)

    Christophorou, L.G.

    1977-01-01

    Recent knowledge on low-energy (mostly approximately less than 10 eV) electron-molecule interaction processes in dilute and in dense gases is synthesized, discussed, and related to the breakdown strength of gaseous dielectrics. Optimal design of multicomponent gaseous insulators can be made on the basis of such knowledge

  18. The use of virtual simulation allows students to interactive learning with creativity and clarity in the theoretical foundation of the pharmacokinetics and pharmacodynamics of the drugs used in pharmacology.

    Directory of Open Access Journals (Sweden)

    Maritza Dorila Placencia Medina

    2015-09-01

    Full Text Available ABSTRACT The use of virtual simulation allows students to interactive learning with creativity and clarity in the theoretical foundation of the pharmacokinetics and pharmacodynamics of the drugs used in pharmacology. Objective: Know the level of satisfaction of students in the design and implementation of virtual simulation laboratory in the Department of Pharmacology, Faculty of Medicine of San Marcos Material and Methods: Descriptive, qualitative study of research-action type. The design and implementation of a virtual simulation laboratory, the intervention of improvement and perfection of teaching materials for the development of practical section of Pharmacology, Faculty of Medicine of San Marcos was planned, using the software Microlab® and CV Rat. A survey of user satisfaction virtual laboratory technique the interview was conducted, as an instrument, using a Likert scale of minimum satisfaction starting in 1 to maximum of 10. Sample size of 26 students. Results: A new process was implemented teaching - learning of Experimental Pharmacology Laboratory using virtual simulation. Most students in the virtual classroom lab have a satisfaction level 9-10 / 10 on the Likert scale. Conclusions: The virtual simulation laboratory Section of Pharmacology got a good level of satisfaction among students.

  19. Effect of scutellarin on the metabolism and pharmacokinetics of clopidogrel in rats.

    Science.gov (United States)

    Chen, Xinmeng; Jin, Jing; Chen, Yaobin; Peng, Lingling; Zhong, Guoping; Li, Jiali; Bi, Huichang; Cai, Yefeng; Huang, Min

    2015-01-01

    Erigeron breviscapus (Vant.) Hand-Mazz, a traditional Chinese medicine, is often co-prescribed with clopidogrel for the treatment of ischemic vascular diseases. Scutellarin is the representative bioactive flavonoid isolated from this herb. The aim of this study was to explore the effect of scutellarin on the metabolism and pharmacokinetics of clopidogrel. The in vitro studies using rat liver microsomes showed that scutellarin significantly inhibited the metabolism of clopidogrel. The IC50 value was 2.1 µM. Ten male rats were employed to investigate the effect of scutellarin on the pharmacokinetics of clopidogrel in vivo. After pretreatment with scutellarin, there were significant increases in the AUC0-∞ (from 0.9 ± 0.4 to 1.7 ± 0.6 ng/ml h; p <0.05) and Cmax (from 0.4 ± 0.1 to 0.9 ± 0.1 ng/ml; p <0.05) of clopidogrel. The pharmacokinetic data for clopidogrel active metabolite showed significant decreases in AUC0-∞ (18.2 ± 5.6 to 11.4 ± 3.7 ng/ml h; p <0.05) and Cmax (from 8.2 ± 1.2 to 4.3 ± 0.3 ng/ml; p <0.05) after pretreatment with scutellarin. Collectively, the metabolism and pharmacokinetics of clopidogrel were significantly affected by scutellarin. This study indicated that potential herb-drug interaction between scutellarin and clopidogrel should be taken into consideration in clinical use. Copyright © 2014 John Wiley & Sons, Ltd.

  20. Clinical Pharmacology and Pharmacokinetics of Levetiracetam

    Directory of Open Access Journals (Sweden)

    Chanin Clark Wright

    2013-12-01

    Full Text Available Status epilepticus and acute repetitive seizures still pose a management challenge despite the recent advances in the field of epilepsy. Parenteral formulations of old anticonvulsants are still a cornerstone in acute seizure management and are approved by the FDA. Intravenous levetiracetam, a second generation anticonvulsant, is approved by the FDA as an adjunctive treatment in patients 16 years or older when oral administration is not available. Data have shown that it has a unique mechanism of action, linear pharmacokinetics and no known drug interactions with other anticonvulsants. In this paper, we will review the current literature about the pharmacology and pharmacokinetics of intravenous levetiracetam and the safety profile of this new anticonvulsant in acute seizure management of both adults and children.

  1. Determination and significance of the Mn(II) Zero-Field Splitting (ZFS) interaction in the geochemistry of travertines

    Energy Technology Data Exchange (ETDEWEB)

    Montegrossi, G. [Istituto di Geoscienze e Georisorse, Consiglio Nazionale delle Ricerche (CNR), via G. La Pira 4, I-50121, Florence (Italy)]. E-mail: giordano@geo.unifi.it; Di Benedetto, F. [Museo di Storia Naturale, Universita di Firenze, via G. La Pira 4, I-50121, Florence (Italy); Minissale, A. [Istituto di Geoscienze e Georisorse, Consiglio Nazionale delle Ricerche (CNR), via G. La Pira 4, I-50121, Florence (Italy); Paladini, M. [Istituto di Geoscienze e Georisorse, Consiglio Nazionale delle Ricerche (CNR), via G. La Pira 4, I-50121, Florence (Italy); Pardi, L.A. [Istituto per i Processi Chimico-Fisici, CNR, via G. Moruzzi 1, I-56124 Pisa (Italy); Romanelli, M. [Dipartimento di Chimica, Universita di Firenze, via della Lastruccia 3, I-50019 Sesto Fiorentino (Italy); Romei, F. [Dipartimento di Biologia Animale e Genetica, Universita di Firenze, Via Romana 17, I-50100 Florence (Italy)

    2006-05-15

    An analytical approach, based on the electron paramagnetic resonance (EPR) spectroscopy of Mn(II) in travertines, has been developed in order to obtain relevant information about the local inhomogeneity of calcite and about the thermodynamic conditions which control the formation of travertine deposits. This information is crucial to constrain the precipitation of travertine under different geochemical contexts. An empirical correlation between the spectral features and the zero-field splitting (ZFS) interaction has been established through numerical simulations of EPR spectra. The variability of the investigated parameters and the applicability of the method have been tested on several travertines from Central Italy.

  2. Determination and significance of the Mn(II) Zero-Field Splitting (ZFS) interaction in the geochemistry of travertines

    International Nuclear Information System (INIS)

    Montegrossi, G.; Di Benedetto, F.; Minissale, A.; Paladini, M.; Pardi, L.A.; Romanelli, M.; Romei, F.

    2006-01-01

    An analytical approach, based on the electron paramagnetic resonance (EPR) spectroscopy of Mn(II) in travertines, has been developed in order to obtain relevant information about the local inhomogeneity of calcite and about the thermodynamic conditions which control the formation of travertine deposits. This information is crucial to constrain the precipitation of travertine under different geochemical contexts. An empirical correlation between the spectral features and the zero-field splitting (ZFS) interaction has been established through numerical simulations of EPR spectra. The variability of the investigated parameters and the applicability of the method have been tested on several travertines from Central Italy

  3. Drug metabolism and pharmacokinetic diversity of ranunculaceae medicinal compounds.

    Science.gov (United States)

    Hao, Da-Cheng; Ge, Guang-Bo; Xiao, Pei-Gen; Wang, Ping; Yang, Ling

    2015-01-01

    The wide-reaching distributed angiosperm family Ranunculaceae has approximately 2200 species in around 60 genera. Chemical components of this family include several representative groups: benzylisoquinoline alkaloid (BIA), ranunculin, triterpenoid saponin and diterpene alkaloid, etc. Their extensive clinical utility has been validated by traditional uses of thousands of years and current evidence-based medicine studies. Drug metabolism and pharmacokinetic (DMPK) studies of plant-based natural products are an indispensable part of comprehensive medicinal plant exploration, which could facilitate conservation and sustainable utilization of Ranunculaceae pharmaceutical resources, as well as new chemical entity development with improved DMPK parameters. However, DMPK characteristics of Ranunculaceaederived medicinal compounds have not been summarized. Black cohosh (Cimicifuga) and goldenseal (Hydrastis) raise concerns of herbdrug interaction. DMPK studies of other Ranunculaceae genera, e.g., Nigella, Delphinium, Aconitum, Trollius, and Coptis, are also rapidly increasing and becoming more and more clinically relevant. In this contribution, we highlight the up-to-date awareness, as well as the challenges around the DMPK-related issues in optimization of drug development and clinical practice of Ranunculaceae compounds. Herb-herb interaction of Ranunculaceae herb-containing traditional Chinese medicine (TCM) formula could significantly influence the in vivo pharmacokinetic behavior of compounds thereof, which may partially explain the complicated therapeutic mechanism of TCM formula. Although progress has been made on revealing the absorption, distribution, metabolism, excretion and toxicity (ADME/T) of Ranunculaceae compounds, there is a lack of DMPK studies of traditional medicinal genera Aquilegia, Thalictrum and Clematis. Fluorescent probe compounds could be promising substrate, inhibitor and/or inducer in future DMPK studies of Ranunculaceae compounds. A better

  4. Clinical Pharmacokinetics of Paclitaxel Monotherapy

    DEFF Research Database (Denmark)

    Stage, Tore B; Bergmann, Troels K; Kroetz, Deanna L

    2018-01-01

    Paclitaxel is an anticancer agent efficacious in the treatment of ovarian, breast, and lung cancer. Due to a strong link between the pharmacokinetics and therapeutic efficacy of paclitaxel, we reviewed the literature on paclitaxel pharmacokinetics. Systematic data mining was performed to extract ...

  5. Effects of amoxicillin/clavulanic acid on the pharmacokinetics of valproic acid

    Directory of Open Access Journals (Sweden)

    Lee SY

    2015-08-01

    Full Text Available Soo-Yun Lee,1 Wooseong Huh,2 Jin Ah Jung,3 Hye Min Yoo,2 Jae-Wook Ko,1,2 Jung-Ryul Kim2,4 1Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, 2Department of Clinical Pharmacology and Therapeutics, Samsung Medical Center, Seoul, 3Department of Clinical Pharmacology, Inje University, Busan Paik Hospital, Busan, 4Department of Clinical Research and Evaluation, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea Abstract: Valproic acid (VPA is mainly metabolized via glucuronide, which is hydrolyzed by β-glucuronidase and undergoes enterohepatic circulation. Amoxicillin/clavulanic acid (AMC administration leads to decreased levels of β-glucuronidase-producing bacteria, suggesting that these antibiotics could interrupt enterohepatic circulation and thereby alter the pharmacokinetics of VPA. This study aimed to evaluate the effects of AMC on the pharmacokinetics of VPA. This was an open-label, two-treatment, one-sequence study in 16 healthy volunteers. Two treatments were evaluated; treatment VPA, in which a single dose of VPA 500 mg was administered, and treatment AMC + VPA, in which multiple doses of AMC 500/125 mg were administered three times daily for 7 days and then a single dose of VPA was administered. Blood samples were collected up to 48 hours. Pharmacokinetic parameters were calculated using noncompartmental methods. Fifteen subjects completed the study. Systemic exposures and peak concentrations of VPA were slightly lower with treatment AMC + VPA than with treatment VPA (AUClast, 851.0 h·mg/L vs 889.6 h·mg/L; Cmax, 52.1 mg/L vs 53.0 mg/L. There were no significant between-treatment effects on pharmacokinetics (95% confidence interval [CI] of AUClast and Cmax (95.7 [85.9–106.5] and 98.3 [91.6–105.6], respectively. Multiple doses of AMC had no significant effects on the pharmacokinetics of VPA; thus, no dose adjustment is necessary. Keywords: drug–drug interaction, pharmacokinetics

  6. Effect of aspirin on the pharmacokinetics and absorption of panax notoginseng saponins.

    Science.gov (United States)

    Tian, Zhihao; Pang, Huanhuan; Zhang, Qiang; Du, Shouying; Lu, Yang; Zhang, Lin; Bai, Jie; Li, Pengyue; Li, Danqi; Zhao, Mengdi; Chen, Xiaonan

    2018-02-01

    Panax notoginseng saponins, a traditional Chinese medicine extraction, and aspirin are both widely used to treat cerebral infarction in China. Good results in clinical practice have been achieved, when Panax notoginseng saponins was taken together with aspirin. To investigate the interaction of the two drugs in vivo, the concentration of notoginsenoside R 1 , ginsenoside Rg 1 , Rb 1 , Re and Rd. in blood were simultaneously measured by UPLC/MS/MS. Sample preparation was carried out by the protein precipitation technique with an internal standard saikosaponin A standard. The separation of six components was achieved by using an ACQUITY UPLC ®BEH C18 column (1.7μm 2.1×100mm) by gradient elution using water (containing 0.2% formic acid) and acetonitrile (containing 0.2% formic acid) as the mobile phase at a flow rate of 0.2mL/min. The pharmacokinetic parameters were determined using non-compartmental analysis. The transport of notoginsenoside R 1 , ginsenoside Rg 1 , Rb 1 , Re and Rd. in MDCK -MDR1 cell monolayer was also used to verify the conclusion of pharmacokinetic drug-drug interaction and study the mechanism of drug interaction. The concentrations of the five components increased in a certain extent when the two drugs administered together in rats. The values of apparent permeability coefficients were significantly increased when the two drugs were used together. Aspirin and salicylic acid could destroy the tight junction protein and open the intercellular space to increase the absorption of Panax notoginseng saponins. Pharmacokinetic drug-drug interaction in vivo existed between Panax notoginseng saponins and aspirin. The drug-drug interaction mainly occurred in the process of absorption. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Pharmacokinetics of Snake Venom

    Directory of Open Access Journals (Sweden)

    Suchaya Sanhajariya

    2018-02-01

    Full Text Available Understanding snake venom pharmacokinetics is essential for developing risk assessment strategies and determining the optimal dose and timing of antivenom required to bind all venom in snakebite patients. This review aims to explore the current knowledge of snake venom pharmacokinetics in animals and humans. Literature searches were conducted using EMBASE (1974–present and Medline (1946–present. For animals, 12 out of 520 initially identified studies met the inclusion criteria. In general, the disposition of snake venom was described by a two-compartment model consisting of a rapid distribution phase and a slow elimination phase, with half-lives of 5 to 48 min and 0.8 to 28 h, respectively, following rapid intravenous injection of the venoms or toxins. When the venoms or toxins were administered intramuscularly or subcutaneously, an initial absorption phase and slow elimination phase were observed. The bioavailability of venoms or toxins ranged from 4 to 81.5% following intramuscular administration and 60% following subcutaneous administration. The volume of distribution and the clearance varied between snake species. For humans, 24 out of 666 initially identified publications contained sufficient information and timed venom concentrations in the absence of antivenom therapy for data extraction. The data were extracted and modelled in NONMEM. A one-compartment model provided the best fit, with an elimination half-life of 9.71 ± 1.29 h. It is intended that the quantitative information provided in this review will provide a useful basis for future studies that address the pharmacokinetics of snakebite in humans.

  8. Performance of the Sellick maneuver significantly improves when residents and trained nurses use a visually interactive guidance device in simulation

    International Nuclear Information System (INIS)

    Connor, Christopher W; Saffary, Roya; Feliz, Eddy

    2013-01-01

    We examined the proper performance of the Sellick maneuver, a maneuver used to reduce the risk of aspiration of stomach contents during induction of general anesthesia, using a novel device that measures and visualizes the force applied to the cricoid cartilage using thin-film force sensitive resistors in a form suitable for in vivo use. Performance was tested in three stages with twenty anaesthesiology residents and twenty trained operating room nurses. Firstly, subjects applied force to the cricoid cartilage as was customary to them. Secondly, subjects used the device to guide the application of that force. Thirdly, subjects were again asked to perform the manoeuvre without visual guidance. Each test lasted 1 min and the amount of force applied was measured throughout. Overall, the Sellick maneuver was often not applied properly, with large variance between individual subjects. Performance and inter-subject consistency improved to a very highly significant degree when subjects were able to use the device as a visual guide (p < 0.001). Subsequent significant improvements in performances during the last, unguided test demonstrated that the device initiated learning. (paper)

  9. Performance of the Sellick maneuver significantly improves when residents and trained nurses use a visually interactive guidance device in simulation

    Energy Technology Data Exchange (ETDEWEB)

    Connor, Christopher W; Saffary, Roya; Feliz, Eddy [Department of Anesthesiology Boston Medical Center, Boston, MA (United States)

    2013-12-15

    We examined the proper performance of the Sellick maneuver, a maneuver used to reduce the risk of aspiration of stomach contents during induction of general anesthesia, using a novel device that measures and visualizes the force applied to the cricoid cartilage using thin-film force sensitive resistors in a form suitable for in vivo use. Performance was tested in three stages with twenty anaesthesiology residents and twenty trained operating room nurses. Firstly, subjects applied force to the cricoid cartilage as was customary to them. Secondly, subjects used the device to guide the application of that force. Thirdly, subjects were again asked to perform the manoeuvre without visual guidance. Each test lasted 1 min and the amount of force applied was measured throughout. Overall, the Sellick maneuver was often not applied properly, with large variance between individual subjects. Performance and inter-subject consistency improved to a very highly significant degree when subjects were able to use the device as a visual guide (p < 0.001). Subsequent significant improvements in performances during the last, unguided test demonstrated that the device initiated learning. (paper)

  10. Medicinal cannabis does not influence the clinical pharmacokinetics of irinotecan and docetaxel.

    Science.gov (United States)

    Engels, Frederike K; de Jong, Floris A; Sparreboom, Alex; Mathot, Ron A A; Loos, Walter J; Kitzen, Jos J E M; de Bruijn, Peter; Verweij, Jaap; Mathijssen, Ron H J

    2007-03-01

    To date, data regarding the potential of cannabinoids to modulate cytochrome P450 isozyme 3A (CYP3A) activity are contradictory. Recently, a standardized medicinal cannabis product was introduced in The Netherlands. We anticipated an increased use of medicinal cannabis concurrent with anticancer drugs, and undertook a drug-interaction study to evaluate the effect of concomitant medicinal cannabis on the pharmacokinetics of irinotecan and docetaxel, both subject to CYP3A-mediated biotransformation. Twenty-four cancer patients were treated with i.v. irinotecan (600 mg, n = 12) or docetaxel (180 mg, n = 12), followed 3 weeks later by the same drugs concomitant with medicinal cannabis (200 ml herbal tea, 1 g/l) for 15 consecutive days, starting 12 days before the second treatment. Blood samples were obtained up to 55 hours after dosing and analyzed for irinotecan and its metabolites (SN-38, SN-38G), respectively, or docetaxel. Pharmacokinetic analyses were performed during both treatments. Results are reported as the mean ratio (95% confidence interval [CI]) of the observed pharmacokinetic parameters with and without concomitant medicinal cannabis. Medicinal cannabis administration did not significantly influence exposure to and clearance of irinotecan (1.04; CI, 0.96-1.11 and 0.97; CI, 0.90-1.05, respectively) or docetaxel (1.11; CI, 0.94-1.28 and 0.95; CI, 0.82-1.08, respectively). Coadministration of medicinal cannabis, as herbal tea, in cancer patients treated with irinotecan or docetaxel does not significantly influence the plasma pharmacokinetics of these drugs. The evaluated variety of medicinal cannabis can be administered concomitantly with both anticancer agents without dose adjustments.

  11. Quantitative determination of trigonelline in mouse serum by means of hydrophilic interaction liquid chromatography-MS/MS analysis: Application to a pharmacokinetic study.

    Science.gov (United States)

    Szczesny, Damian; Bartosińska, Ewa; Jacyna, Julia; Patejko, Małgorzata; Siluk, Danuta; Kaliszan, Roman

    2018-02-01

    Trigonelline is a pyridine alkaloid found in fenugreek seeds and coffee beans. Most of the previous studies are concerned with the quantification of trigonelline along with other constituents in coffee herbs or beverages. Only a few have focused on its determination in animal or human tissues by applying different modes of HPLC with UV or MS detection. The aim of the study was to develop and validate a fast and simple method for trigonelline determination in serum by the use of hydrophilic interaction liquid chromatography (HILIC) with ESI-MS/MS detection. Separation of trigonelline was achieved on a Kinetex HILIC column operated at 35°C with acetonitrile-ammonium formate (10 mm, pH = 3) buffer mixture (55:45, v/v) as the mobile phase. The developed method was successfully applied to determine trigonelline concentration in mouse serum after intravenous administration of 10 mg/kg. The developed assay is sensitive (limit of detection = 1.5 ng/mL, limit of quantification = 5.0 ng/mL) and linear in a concentration range from 5.0 to 250.0 ng/mL. Sample preparation is limited to deproteinization, centrifugation and filtration. The application of the HILIC mode of chromatography with MS detection and selection of deuterated trigonelline as internal standard allowed a rapid and precise method of trigonelline quantification to be to developed. Copyright © 2017 John Wiley & Sons, Ltd.

  12. Bioavailability of the sodium pertechnetate and morphometry of organs isolated from rats: study of possible pharmacokinetic interactions of a ginkgo biloba extract

    International Nuclear Information System (INIS)

    Moreno, Silvana Ramos Farias; Arnobio, Adriano; Caldas, Luiz Querino de Araujo; Carvalho, Jorge Jose; Nascimento, Ana Lucia; Pereira, Mario; Dire, Glaucio; Bernardo Filho, Mario; Rocha, Emely Kazan

    2005-01-01

    Many compounds affect the bioavailability of radiobiocomplexes as radiopharmaceuticals. Ginkgo Biloba extract (EGb) has several effects. The influence of an EGb on the bioavailability of the radiobiocomplex sodium pertechnetate (Na 99m TcO 4 ) and on the morphometry of the organs was evaluated. Rats were treated with EGb and Na 99m TcO 4 was injected. The animals were sacrificed; the radioactivity in the organs was counted. The results showed that EGb altered the Na 99m TcO 4 bioavailability in the kidneys, liver and duodenum. Morphometric analysis of the organs showed significant alterations (P 99m TcO 4 . (author)

  13. Enhancement of Exposure and Reduction of Elimination for Paeoniflorin or Albiflorin via Co-Administration with Total Peony Glucosides and Hypoxic Pharmacokinetics Comparison

    Directory of Open Access Journals (Sweden)

    Weizhe Xu

    2016-07-01

    Full Text Available There is evidence suggesting that herbal extracts demonstrate greater bioactivities than their isolated constituents at an equivalent dose. This phenomenon could be attributed to the absence of interacting substances present in the extracts. By measuring the pharmacokinetic parameters of paeoniflorin (PF and albiflorin (AF after being orally administered to rats in isolated form, in combination with each other and within total peony glucosides (TPG, respectively, the current study aimed to identify positive pharmacokinetic interactions between components of peony radix extracts. Moreover, the pharmacokinetic profiles of PF and AF under normoxia and hypoxia were also investigated and compared. In order to achieve these goals, a highly sensitive and reproducible ultra-peformance liquid chromatography–mass spectrometry (UPLC-MS method was developed and validated for simultaneously quantitation of PF and AF in rat plasma. This study found that compared with that of single component (PF/AF, the exposure of PF in rat plasma after combination administration or TPG administration was significantly increased, meanwhile the elimination of PF/AF was remarkably reduced. It was also noticed that AUC and Cmax of PF in hypoxia rats were significantly decreased compared with that of normaxia rats, suggesting that there was a decreased exposure of PF in rats under hypoxia. The current study, for the first time, revealed the pharmacokinetic interactions between PF/AF and other constitutes in TGP and the pharmacokinetic profiles of PF and AF under hypoxia. In view of the current findings, it could be supposed that the clinical performance of total peony glucosides would be better than that of single constitute (PF/AF. The outcomes of this animal study are expected to serve as a basis for development of clinical guidelines on total peony glucosides usage.

  14. Influence of B-Complex Vitamins on the Pharmacokinetics of Ginsenosides Rg1, Rb1, and Ro After Oral Administration.

    Science.gov (United States)

    Zheng, Peihe; Chen, Yinbin; Fu, Yangyang; Wang, Hecheng; Wang, Jia; Zheng, Siwen; Xiao, Shengyuan; Wang, Yingping

    2017-11-01

    After cultivation of ginseng, ginsenosides, which are the major active ingredients of gingeng, were approved for use by the food industry, and began to be used as added functional ingredients to try to improve the quality and price of functional foods. However, the interaction between different types of ginsenosides and nutrients needs further study. We investigated the effect of B-complex vitamins (which are essential nutrients) on the pharmacokinetics of the ginsenosides protopanaxatriol-type saponin Rg 1 , protopanaxadiol-type saponin Rb 1 , and oleanolic acid-type saponin Ro after oral administration. Ginsenosides Rg 1 , Rb 1 , and Ro, with or without B-complex vitamins, respectively, were administered orally to rats to evaluate their pharmacokinetics. The concentration of ginsenosides in plasma was determined by liquid chromatography/tandem mass spectrometry. Pharmacokinetic parameters were fitted using WinNonlin v6.2. After oral coadministration with B-complex vitamins, the area under the concentration-time curve from zero to infinity (AUC 0-∞ ) of ginsenoside Rg 1 was reduced by 70%, that of ginsenoside Rb 1 was reduced by 43%, and that of ginsenoside Ro was reduced by 34%. The AUC 0-∞ of ginsenosides Rg 1 and Rb 1 showed significant differences between different treatments, but the AUC 0-∞ of ginsenoside Ro did not. These results suggest significant ginsenoside-nutrient interactions between ginsenosides Rg 1 , Rb 1 , and B-complex vitamins.

  15. Pharmacokinetics of antiretroviral drugs in infancy | McIlleron ...

    African Journals Online (AJOL)

    Dosing in infancy is complicated by inadequate characterisation of pharmacokinetics, unpredictable drug concentrations and a lack of suitable dosage forms. Additional challenges are presented by the concomitant administration of interacting drugs (e.g. rifampicin in antituberculosis treatment) and disease conditions that ...

  16. Pharmacokinetics of Naja sumatrana (equatorial spitting cobra venom and its major toxins in experimentally envenomed rabbits.

    Directory of Open Access Journals (Sweden)

    Michelle Khai Khun Yap

    2014-06-01

    Full Text Available The optimization of snakebite management and the use of antivenom depend greatly on the knowledge of the venom's composition as well as its pharmacokinetics. To date, however, pharmacokinetic reports on cobra venoms and their toxins are still relatively limited. In the present study, we investigated the pharmacokinetics of Naja sumatrana (Equatorial spitting cobra venom and its major toxins (phospholipase A2, neurotoxin and cardiotoxin, following intravenous and intramuscular administration into rabbits.The serum antigen concentration-time profile of the N. sumatrana venom and its major toxins injected intravenously fitted a two-compartment model of pharmacokinetics. The systemic clearance (91.3 ml/h, terminal phase half-life (13.6 h and systemic bioavailability (41.9% of N. sumatrana venom injected intramuscularly were similar to those of N. sputatrix venom determined in an earlier study. The venom neurotoxin and cardiotoxin reached their peak concentrations within 30 min following intramuscular injection, relatively faster than the phospholipase A2 and whole venom (Tmax=2 h and 1 h, respectively. Rapid absorption of the neurotoxin and cardiotoxin from the injection site into systemic circulation indicates fast onsets of action of these principal toxins that are responsible for the early systemic manifestation of envenoming. The more prominent role of the neurotoxin in N. sumatrana systemic envenoming is further supported by its significantly higher intramuscular bioavailability (Fi.m.=81.5% compared to that of the phospholipase A2 (Fi.m.=68.6% or cardiotoxin (Fi.m.=45.6%. The incomplete absorption of the phospholipase A2 and cardiotoxin may infer the toxins' affinities for tissues at the injection site and their pathological roles in local tissue damages through synergistic interactions.Our results suggest that the venom neurotoxin is absorbed very rapidly and has the highest bioavailability following intramuscular injection, supporting its

  17. Insulin aspart pharmacokinetics

    DEFF Research Database (Denmark)

    Rasmussen, Christian Hove; Roge, Rikke Meldgaard; Ma, Zhulin

    2014-01-01

    Background: Insulin aspart (IAsp) is used by many diabetics as a meal-time insulin to control postprandial glucose levels. As is the case with many other insulin types, the pharmacokinetics (PK), and consequently the pharmacodynamics (PD), is associated with clinical variability, both between...... to investigate and quantify the properties of the subcutaneous depot. Data from Brange et al. (1990) are used to determine the effects of insulin chemistry in subcutis on the absorption rate. Intravenous (i.v.) bolus and infusion PK data for human insulin are used to understand and quantify the systemic...... distribution and elimination (Porksen et al., 1997; Sjostrand et al., 2002). PK and PD profiles for type 1 diabetics from Chen et al. (2005) are analyzed to demonstrate the effects of IAsp antibodies in terms of bound and unbound insulin. PK profiles from Thorisdottir et al. (2009) and Ma et al. (2012b...

  18. Pharmacokinetics of Cannabinoids

    Directory of Open Access Journals (Sweden)

    Iain J McGilveray

    2005-01-01

    Full Text Available Delta-9-tetrahydrocannabinol (Δ-9-THC is the main psychoactive ingredient of cannabis (marijuana. The present review focuses on the pharmacokinetics of THC, but also includes known information for cannabinol and cannabidiol, as well as the synthetic marketed cannabinoids, dronabinol (synthetic THC and nabilone. The variability of THC in plant material (0.3% to 30% leads to variability in tissue THC levels from smoking, which is, in itself, a highly individual process. THC bioavailability averages 30%. With a 3.55% THC cigarette, a peak plasma level of 152±86.3 ng/mL occured approximately 10 min after inhalation. Oral THC, on the other hand, is only 4% to 12% bioavailable and absorption is highly variable. THC is eliminated from plasma in a multiphasic manner, with low amounts detectable for over one week after dosing. A major active 11-hydroxy metabolite is formed after both inhalation and oral dosing (20% and 100% of parent, respectively. THC is widely distributed, particularly to fatty tissues, but less than 1% of an administered dose reaches the brain, while the spleen and body fat are long-term storage sites. The elimination of THC and its many metabolites (from all routes occurs via the feces and urine. Metabolites persist in the urine and feces for severalweeks. Nabilone is well absorbed and the pharmacokinetics, although variable, appear to be linear from oral doses of 1 mg to 4 mg (these doses show a plasma elimination half-life of approximately 2 h. As with THC, there is a high first-pass effect, and the feces to urine ratio of excretion is similar to other cannabinoids. Pharmacokineticpharmacodynamic modelling with plasma THC versus cardiac and psychotropic effects show that after equilibrium is reached, the intensity of effect is proportional to the plasma THC profile. Clinical trials have found that nabilone produces less tachycardia and less euphoria than THC for a similar antiemetic response.

  19. [Predictive factors of clinically significant drug-drug interactions among regimens based on protease inhibitors, non-nucleoside reverse transcriptase inhibitors and raltegravir].

    Science.gov (United States)

    Cervero, Miguel; Torres, Rafael; Jusdado, Juan José; Pastor, Susana; Agud, Jose Luis

    2016-04-15

    To determine the prevalence and types of clinically significant drug-drug interactions (CSDI) in the drug regimens of HIV-infected patients receiving antiretroviral treatment. retrospective review of database. Centre: Hospital Universitario Severo Ochoa, Infectious Unit. one hundred and forty-two participants followed by one of the authors were selected from January 1985 to December 2014. from their outpatient medical records we reviewed information from the last available visit of the participants, in relation to HIV infection, comorbidities, demographics and the drugs that they were receiving; both antiretroviral drugs and drugs not related to HIV infection. We defined CSDI from the information sheet and/or database on antiretroviral drug interactions of the University of Liverpool (http://www.hiv-druginteractions.org) and we developed a diagnostic tool to predict the possibility of CSDI. By multivariate logistic regression analysis and by estimating the diagnostic performance curve obtained, we identified a quick tool to predict the existence of drug interactions. Of 142 patients, 39 (29.11%) had some type of CSDI and in 11.2% 2 or more interactions were detected. In only one patient the combination of drugs was contraindicated (this patient was receiving darunavir/r and quetiapine). In multivariate analyses, predictors of CSDI were regimen type (PI or NNRTI) and the use of 3 or more non-antiretroviral drugs (AUC 0.886, 95% CI 0.828 to 0.944; P=.0001). The risk was 18.55 times in those receiving NNRTI and 27,95 times in those receiving IP compared to those taking raltegravir. Drug interactions, including those defined as clinically significant, are common in HIV-infected patients treated with antiretroviral drugs, and the risk is greater in IP-based regimens. Raltegravir-based prescribing, especially in patients who receive at least 3 non-HIV drugs could avoid interactions. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  20. Pharmacokinetics of clomipramine during pregnancy

    NARCIS (Netherlands)

    Ter Horst, P G J; Proost, J H; Smit, J P; Vries, M T; de Jong-van den Berg, Lolkje; Wilffert, B

    2015-01-01

    Clomipramine is one of the drugs for depression during pregnancy; however, pharmacokinetic data of clomipramine and its active metabolite desmethylclomipramine in this vulnerable period are lacking. In this study, we describe clomipramine and desmethylclomipramine concentrations including their

  1. Pharmacokinetics of linezolid in critically ill patients.

    Science.gov (United States)

    Sazdanovic, Predrag; Jankovic, Slobodan M; Kostic, Marina; Dimitrijevic, Aleksandra; Stefanovic, Srdjan

    2016-06-01

    Linezolid is an oxazolidinone antibiotic active against Gram-positive bacteria, and is most commonly used to treat life-threatening infections in critically ill patients. The pharmacokinetics of linezolid are profoundly altered in critically ill patients, partly due to decreased function of vital organs, and partly because life-sustaining drugs and devices may change the extent of its excretion. This article is summarizes key changes in the pharmacokinetics of linezolid in critically ill patients. The changes summarized are clinically relevant and may serve as rationale for dosing recommendations in this particular population. While absorption and penetration of linezolid to tissues are not significantly changed in critically ill patients, protein binding of linezolid is decreased, volume of distribution increased, and metabolism may be inhibited leading to non-linear kinetics of elimination; these changes are responsible for high inter-individual variability of linezolid plasma concentrations, which requires therapeutic plasma monitoring and choice of continuous venous infusion as the administration method. Acute renal or liver failure decrease clearance of linezolid, but renal replacement therapy is capable of restoring clearance back to normal, obviating the need for dosage adjustment. More population pharmacokinetic studies are necessary which will identify and quantify the influence of various factors on clearance and plasma concentrations of linezolid in critically ill patients.

  2. PHARMACOKINETIC RESEARCHES AND PRACTICAL MEDICINE

    Directory of Open Access Journals (Sweden)

    V. G. Belolipetskaya

    2015-12-01

    Full Text Available An article gives in a comprehensive manner the main idea of pharmacokinetics, as the science about rules of substances behavior in the internal environment of the organism, as well as of main parameters of pharmacokinetic researches. The article provides vivid and very  persuasive examples of high practical importance of this science both for creating new medical forms of drugs and for choosing the optimal of therapy regime.

  3. PHARMACOKINETIC RESEARCHES AND PRACTICAL MEDICINE

    Directory of Open Access Journals (Sweden)

    V. G. Belolipetskaya

    2005-01-01

    Full Text Available An article gives in a comprehensive manner the main idea of pharmacokinetics, as the science about rules of substances behavior in the internal environment of the organism, as well as of main parameters of pharmacokinetic researches. The article provides vivid and very  persuasive examples of high practical importance of this science both for creating new medical forms of drugs and for choosing the optimal of therapy regime.

  4. Laboratory simulation reveals significant impacts of ocean acidification on microbial community composition and host-pathogen interactions between the blood clam and Vibrio harveyi.

    Science.gov (United States)

    Zha, Shanjie; Liu, Saixi; Su, Wenhao; Shi, Wei; Xiao, Guoqiang; Yan, Maocang; Liu, Guangxu

    2017-12-01

    It has been suggested that climate change may promote the outbreaks of diseases in the sea through altering the host susceptibility, the pathogen virulence, and the host-pathogen interaction. However, the impacts of ocean acidification (OA) on the pathogen components of bacterial community and the host-pathogen interaction of marine bivalves are still poorly understood. Therefore, 16S rRNA high-throughput sequencing and host-pathogen interaction analysis between blood clam (Tegillarca granosa) and Vibrio harveyi were conducted in the present study to gain a better understanding of the ecological impacts of ocean acidification. The results obtained revealed a significant impact of ocean acidification on the composition of microbial community at laboratory scale. Notably, the abundance of Vibrio, a major group of pathogens to many marine organisms, was significantly increased under ocean acidification condition. In addition, the survival rate and haemolytic activity of V. harveyi were significantly higher in the presence of haemolymph of OA treated T. granosa, indicating a compromised immunity of the clam and enhanced virulence of V. harveyi under future ocean acidification scenarios. Conclusively, the results obtained in this study suggest that future ocean acidification may increase the risk of Vibrio pathogen infection for marine bivalve species, such as blood clams. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Preparation of finasteride capsules-loaded drug nanoparticles: formulation, optimization, in vitro, and pharmacokinetic evaluation

    Directory of Open Access Journals (Sweden)

    Ahmed TA

    2016-02-01

    Full Text Available Tarek A Ahmed1,2 1Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia; 2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt Abstract: In this study, optimized freeze-dried finasteride nanoparticles (NPs were prepared from drug nanosuspension formulation that was developed using the bottom–up technique. The effects of four formulation and processing variables that affect the particle size and solubility enhancement of the NPs were explored using the response surface optimization design. The optimized formulation was morphologically characterized using transmission electron microscopy (TEM. Physicochemical interaction among the studied components was investigated. Crystalline change was investigated using X-ray powder diffraction (XRPD. Crystal growth of the freeze-dried NPs was compared to the corresponding aqueous drug nanosuspension. Freeze-dried NPs formulation was subsequently loaded into hard gelatin capsules that were examined for in vitro dissolution and pharmacokinetic behavior. Results revealed that in most of the studied variables, some of the quadratic and interaction effects had a significant effect on the studied responses. TEM image illustrated homogeneity and shape of the prepared NPs. No interaction among components was noticed. XRPD confirmed crystalline state change in the optimized NPs. An enhancement in the dissolution rate of more than 2.5 times from capsules filled with optimum drug NPs, when compared to capsules filled with pure drug, was obtained. Crystal growth, due to Ostwald ripening phenomenon and positive Gibbs free energy, was reduced following lyophilization of the nanosuspension formulation. Pharmacokinetic parameters from drug NPs were superior to that of pure drug and drug microparticles. In conclusion, freeze-dried NPs based on drug nanosuspension formulation is a successful

  6. A comprehensive review of recent studies on pharmacokinetics of traditional Chinese medicines (2014-2017) and perspectives.

    Science.gov (United States)

    Shi, Peiying; Lin, Xinhua; Yao, Hong

    2018-05-01

    Traditional Chinese medicines (TCMs) have a long history for safely treating human diseases. Unlike western medicine, TCMs usually contain multiple components synergistically and holistically acting on the diseases. It remains a big challenge to represent rationally the in vivo process of multiple components of TCMs for understanding the relationship between administration and therapeutic effects. For years, efforts were always made to face the challenge, and the achievements were obvious. Here, we give an comprehensive overview of the recent investigation progress (from 2015 to 2017, except the part of 'integrated pharmacokinetics of TCMs' from 2014 to 2017 and the part of 'reverse pharmacokinetics in drug discovery from natural medicines' in 2014) on pharmacokinetics of TCMs, mainly referring to the following six aspects: (1) classical pharmacokinetic studies on TCMs; (2) absorbed components and metabolites identification of TCMs; (3) pharmacokinetic herb-drug interactions and herb-herb interactions with TCMs; (4) integrated pharmacokinetics of TCMs; (5) pharmacokinetic and pharmacodynamic combination studies to dissect the action mechanisms of TCMs; and (6) reverse pharmacokinetics in drug discovery from natural medicines. Finally, based on the insights from the recent progress and our latest efforts, we propose new perspectives on the integrated pharmacokinetics of TCMs.

  7. Pharmacokinetic studies of neuromuscular blocking agents: Good Clinical Research Practice (GCRP)

    DEFF Research Database (Denmark)

    Viby-Mogensen, J.; Østergaard, D.; Donati, F.

    2000-01-01

    Good Clinical Research Practice (GCRP), neuromuscular blocking agents, pharmacokinetics, pharmacokinetic/pharmacodynamic modeling, population pharmacokinetics, statistics, study design......Good Clinical Research Practice (GCRP), neuromuscular blocking agents, pharmacokinetics, pharmacokinetic/pharmacodynamic modeling, population pharmacokinetics, statistics, study design...

  8. Study on influence of piperine treatment on the pharmacokinetics of diclofenac in healthy volunteers.

    Science.gov (United States)

    Bedada, Satish Kumar; Boga, Praveen Kumar; Kotakonda, Harish Kaushik

    2017-02-01

    1. Diclofenac sodium (DIC) is a widely used anti-inflammatory drug and its administration in humans receiving long-term therapy with herbal drugs containing piperine (PIP) may occur, which leads to drug-phytochemical interactions. The purpose of the present study was to investigate the influence of PIP treatment on the pharmacokinetics of DIC in healthy volunteers. 2. The open-label, two period, sequential study was conducted in 12 healthy volunteers. PIP 20 mg was administered once daily for 10 days during treatment phase. A single dose of DIC 100 mg was administered during control and after treatment phases under fasting conditions. The blood samples were collected after DIC dosing at predetermined time intervals and analyzed by HPLC. 3. Treatment with PIP significantly enhanced maximum plasma concentration (C max ) (2.24-3.68 μg/mL, p pharmacokinetics of DIC might be attributed to PIP mediated inhibition of CYP2C9 enzyme, which indicates the clinically significant interaction present between DIC and PIP. Therefore, the combination therapy of DIC along with PIP may represent a novel approach to reduce dosage and result in reduced incidence of gastrointestinal side effects seen with DIC alone at higher doses.

  9. Pharmacokinetics of oral terbinafine in adult horses.

    Science.gov (United States)

    Younkin, T J; Davis, E G; Kukanich, B

    2017-08-01

    The primary study objective was to compare the pharmacokinetics of p.o. terbinafine alone to p.o. terbinafine administered with p.o. cimetidine in healthy adult horses. The second objective was to assess the pharmacokinetics of terbinafine when administered per rectum in two different suspensions at 30 mg/kg to adult horses. Six healthy adult horses were included in this crossover study. Plasma terbinafine concentrations were quantified with liquid chromatography and mass spectrometry. The half-life (geometric mean) was 8.38 and 10.76 h, for p.o. alone and p.o. with cimetidine, respectively. The mean maximum plasma concentrations were 0.291 μg/mL at 1.54 h and 0.418 μg/mL at 1.28 h for p.o. alone and p.o. with cimetidine, respectively. Terbinafine with cimetidine had an average C MAX 44% higher and the relative F was 153% compared p.o. terbinafine alone, but was not statistically different (P > 0.05). Terbinafine was infrequently detected when administered per rectum in two different suspensions (water or olive oil). Minor adverse effects included oral irritation, fever, and colic. All resolved spontaneously. More pharmacokinetic studies are indicated assessing drug-drug interactions and using multiple dosing intervals to improve our knowledge of effective oral dosing, the potential for drug accumulation, and systemic adverse effect of terbinafine in horses. © 2016 John Wiley & Sons Ltd.

  10. Impact of pharmaceutical cocrystals: the effects on drug pharmacokinetics.

    Science.gov (United States)

    Shan, Ning; Perry, Miranda L; Weyna, David R; Zaworotko, Michael J

    2014-09-01

    Pharmaceutical cocrystallization has emerged in the past decade as a new strategy to enhance the clinical performance of orally administered drugs. A pharmaceutical cocrystal is a multi-component crystalline material in which the active pharmaceutical ingredient is in a stoichiometric ratio with a second compound that is generally a solid under ambient conditions. The resulting cocrystal exhibits different solid-state thermodynamics, leading to changes in physicochemical properties that offer the potential to significantly modify drug pharmacokinetics. The impact of cocrystallization upon drug pharmacokinetics has not yet been well delineated. Herein, we compile previously published data to address two salient questions: what effect does cocrystallization impart upon physicochemical properties of a drug substance and to what degree can those effects impact its pharmacokinetics. Cocrystals can impact various aspects of drug pharmacokinetics, including, but not limited to, drug absorption. The diversity of solid forms offered through cocrystallization can facilitate drastic changes in solubility and pharmacokinetics. Therefore, it is unsurprising that cocrystal screening is now a routine step in early-stage drug development. With the increasing recognition of pharmaceutical cocrystals from clinical, regulatory and legal perspectives, the systematic commercialization of cocrystal containing drug products is just a matter of time.

  11. Ofloxacin pharmacokinetics in renal failure.

    OpenAIRE

    Fillastre, J P; Leroy, A; Humbert, G

    1987-01-01

    The pharmacokinetics of ofloxacin were investigated in 12 normal subjects and 21 uremic patients after the administration of a single oral 200-mg dose. An open three-compartment body model was used to calculate ofloxacin pharmacokinetic parameters. In healthy subjects, the peak plasma level averaged 2.24 +/- 0.90 micrograms/ml and was obtained at 0.83 +/- 0.31 h. The absorption rate constant was 4.22 +/- 1.64 h-1. The terminal half-life was 7.86 +/- 1.81 h. The apparent volume of distribution...

  12. PHARMACOKINETICS AND PHARMACOKINETIC DYNAMIC RELATIONSHIP OF ROCURONIUM BROMIDE IN HUMANS

    NARCIS (Netherlands)

    WIERDA, JMKH; PROOST, JH; SCHIERE, S; HOMMES, FDM

    The existing human pharmacokinetic studies have been reviewed and compared with data derived from animals. The earliest study confirms the similarity of rocuronium to vecuronium with respect to the variables derived from the plasma concentration decay curves and the proportion excreted renally.

  13. Association of pharmacokinetic and metabolic parameters derived using simultaneous PET/MRI: Initial findings and impact on response evaluation in breast cancer.

    Science.gov (United States)

    Jena, Amarnath; Taneja, Sangeeta; Singh, Aru; Negi, Pradeep; Mehta, Shashi Bhushan; Ahuja, Aashim; Singhal, Manish; Sarin, Ramesh

    2017-07-01

    To study relationships among pharmacokinetic and 18 F-fluorodeoxyglucose ( 18 F-FDG) PET parameters obtained through simultaneous PET/MRI in breast cancer patients and evaluate their combined potential for response evaluation. The study included 41 breast cancer patients for correlation study and 9 patients (pre and post therapy) for response evaluation. All patients underwent simultaneous PET/MRI with dedicated breast imaging. Pharmacokinetic parameters and PET parameters for tumor were derived using an in- house developed and vendor provided softwares respectively. Relationships between SUV and pharmacokinetic parameters and clinical as well as histopathologic parameters were evaluated using Spearman correlation analysis. Response to chemotherapy was derived as percentage reduction in size and in parameters post therapy. Significant correlations were observed between SUVmean, max, peak, TLG with K trans (ρ=0.446, 0.417, 0.491, 0.430; p≤0.01); with Kep(ρ=0.303, ρ=0.315, ρ=0.319; p≤0.05); and with iAUC(ρ=0.401, ρ=0.410, ρ=0.379; p≤0.05, p≤0.01). The ratio of ve/iAUC showed significant negative correlation to SUVmean, max, peak and TLG (ρ=0.420, 0.446, 0.443, 0.426; p≤0.01). Ability of SUV as well as pharmacokinetic parameters to predict response to therapy matched the RECIST criteria in 9 out of 11 lesions in 9 patients. Maximum post therapy quantitative reduction was observed in SUVpeak, TLG and K trans . Simultaneous PET/MRI enables illustration of close interactions between glucose metabolism and pharmacokinetic parameters in breast cancer patients and potential of their simultaneity in response assessment to therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Effect of Dehydration on the Pharmacokinetics of Mefenamic Acid

    OpenAIRE

    QAMAR, Shadab

    2014-01-01

    The pharmacokinetic properties and bioavailability of mefenamic acid was studied in normal and dehydrated rabbits. High perfomance liquid chromatography (HPLC) was used for the assay of mefenamic acid in plasma samples. The mean plasma concentration and area under the plasma concentration-time curve decreased but the volume of distribution and total body clearance increased significantly (P

  15. Stoichiometric balance of protein copy numbers is measurable and functionally significant in a protein-protein interaction network for yeast endocytosis.

    Science.gov (United States)

    Holland, David O; Johnson, Margaret E

    2018-03-01

    Stoichiometric balance, or dosage balance, implies that proteins that are subunits of obligate complexes (e.g. the ribosome) should have copy numbers expressed to match their stoichiometry in that complex. Establishing balance (or imbalance) is an important tool for inferring subunit function and assembly bottlenecks. We show here that these correlations in protein copy numbers can extend beyond complex subunits to larger protein-protein interactions networks (PPIN) involving a range of reversible binding interactions. We develop a simple method for quantifying balance in any interface-resolved PPINs based on network structure and experimentally observed protein copy numbers. By analyzing such a network for the clathrin-mediated endocytosis (CME) system in yeast, we found that the real protein copy numbers were significantly more balanced in relation to their binding partners compared to randomly sampled sets of yeast copy numbers. The observed balance is not perfect, highlighting both under and overexpressed proteins. We evaluate the potential cost and benefits of imbalance using two criteria. First, a potential cost to imbalance is that 'leftover' proteins without remaining functional partners are free to misinteract. We systematically quantify how this misinteraction cost is most dangerous for strong-binding protein interactions and for network topologies observed in biological PPINs. Second, a more direct consequence of imbalance is that the formation of specific functional complexes depends on relative copy numbers. We therefore construct simple kinetic models of two sub-networks in the CME network to assess multi-protein assembly of the ARP2/3 complex and a minimal, nine-protein clathrin-coated vesicle forming module. We find that the observed, imperfectly balanced copy numbers are less effective than balanced copy numbers in producing fast and complete multi-protein assemblies. However, we speculate that strategic imbalance in the vesicle forming module

  16. [Diagnostic value of quantitative pharmacokinetic parameters and relative quantitative pharmacokinetic parameters in breast lesions with dynamic contrast-enhanced MRI].

    Science.gov (United States)

    Sun, T T; Liu, W H; Zhang, Y Q; Li, L H; Wang, R; Ye, Y Y

    2017-08-01

    Objective: To explore the differential between the value of dynamic contrast-enhanced MRI quantitative pharmacokinetic parameters and relative pharmacokinetic quantitative parameters in breast lesions. Methods: Retrospective analysis of 255 patients(262 breast lesions) who was obtained by clinical palpation , ultrasound or full-field digital mammography , and then all lessions were pathologically confirmed in Zhongda Hospital, Southeast University from May 2012 to May 2016. A 3.0 T MRI scanner was used to obtain the quantitative MR pharmacokinetic parameters: volume transfer constant (K(trans)), exchange rate constant (k(ep))and extravascular extracellular volume fraction (V(e)). And measured the quantitative pharmacokinetic parameters of normal glands tissues which on the same side of the same level of the lesions; and then calculated the value of relative pharmacokinetic parameters: rK(rans)、rk(ep) and rV(e).To explore the diagnostic value of two pharmacokinetic parameters in differential diagnosis of benign and malignant breast lesions using receiver operating curves and model of logistic regression. Results: (1)There were significant differences between benign lesions and malignant lesions in K(trans) and k(ep) ( t =15.489, 15.022, respectively, P 0.05). The areas under the ROC curve(AUC)of K(trans), k(ep) and V(e) between malignant and benign lesions were 0.933, 0.948 and 0.387, the sensitivity of K(trans), k(ep) and V(e) were 77.1%, 85.0%, 51.0% , and the specificity of K(trans), k(ep) and V(e) were 96.3%, 93.6%, 60.8% for the differential diagnosis of breast lesions if taken the maximum Youden's index as cut-off. (2)There were significant differences between benign lesions and malignant lesions in rK(trans), rk(ep) and rV(e) ( t =14.177, 11.726, 2.477, respectively, P quantitative pharmacokinetic parameters and the prediction probability of relative quantitative pharmacokinetic parameters( Z =0.867, P =0.195). Conclusion: There was no significant

  17. Pharmacokinetic-Pharmacodynamic (PKPD) Analysis with Drug Discrimination.

    Science.gov (United States)

    Negus, S Stevens; Banks, Matthew L

    2016-08-30

    Discriminative stimulus and other drug effects are determined by the concentration of drug at its target receptor and by the pharmacodynamic consequences of drug-receptor interaction. For in vivo procedures such as drug discrimination, drug concentration at receptors in a given anatomical location (e.g., the brain) is determined both by the dose of drug administered and by pharmacokinetic processes of absorption, distribution, metabolism, and excretion that deliver drug to and from that anatomical location. Drug discrimination data are often analyzed by strategies of dose-effect analysis to determine parameters such as potency and efficacy. Pharmacokinetic-Pharmacodynamic (PKPD) analysis is an alternative to conventional dose-effect analysis, and it relates drug effects to a measure of drug concentration in a body compartment (e.g., venous blood) rather than to drug dose. PKPD analysis can yield insights on pharmacokinetic and pharmacodynamic determinants of drug action. PKPD analysis can also facilitate translational research by identifying species differences in pharmacokinetics and providing a basis for integrating these differences into interpretation of drug effects. Examples are discussed here to illustrate the application of PKPD analysis to the evaluation of drug effects in rhesus monkeys trained to discriminate cocaine from saline.

  18. Mefloquine pharmacokinetics in healthy subjects and in peptic ulcer patients after cimetidine administration.

    Science.gov (United States)

    Kolawole, J A; Mustapha, A; Abudu-Aguye, I; Ochekpe, N

    2000-01-01

    The pharmacokinetics of orally administered mefloquine were determined in six healthy male subjects and in six ulcer patients before and after a 3-day course of cimetidine (400 mg morning and evening). Peak plasma concentrations Cmax and AUC0-infinity were similarly and significantly (P infinity was increased by 37.5% in healthy and peptic ulcer subjects respectively. The values of t1/2ab absorption and t1/2 beta elimination, total crearance CLT/F and volume of distribution were altered to varying levels after cimetidine treatment but the changes were not statistically significant in both healthy and peptic ulcer subjects. The established long t1/2 beta and this apparent interaction between mefloquine and cimetidine which resulted in increased mefloquine plasma concentration might be of clinical significant in patients with neurological/psychiatric history.

  19. Clinical pharmacokinetics of nisoldipine coat-core.

    Science.gov (United States)

    Heinig, R

    1998-09-01

    Nisoldipine, a calcium antagonist of the dihydropyridine type, is the active ingredient of the controlled release nisoldipine coat-core (CC) formulation. In humans, the absorption from nisoldipine CC occurs across the entire gastrointestinal tract with an increase in bioavailability in the colon because of the lower concentrations of metabolising enzymes in the distal gut wall. Although nisoldipine is almost completely absorbed, its absolute bioavailability from the CC tablet is only 5.5%, as a result of significant first-pass metabolism in the gut and liver. Nisoldipine is a high-clearance drug with substantial interindividual and relatively lower intraindividual variability in pharmacokinetics, dependent on liver blood flow. Nisoldipine is highly (> 99%) protein bound. Its elimination is almost exclusively via the metabolic route and renal excretion of metabolites dominates over excretion in the faeces. Although nisoldipine is administered as a racemic mixture, its plasma concentrations are almost entirely caused by the eutomer as a result of highly stereoselective intrinsic clearance. Nisoldipine CC demonstrates linear pharmacokinetics in the therapeutic dose range and its steady-state pharmacokinetics are predictable from single dose data. Steady-state is reached with the second dose when the drug is given once daily and the peak-trough fluctuations in plasma concentration is minimal. Plasma-concentrations of nisoldipine increase with age. Careful dose titration according to individual clinical response is recommended in the elderly. Nisoldipine CC should not be used in patients with liver cirrhosis, though dosage adjustments in patients with renal impairment are not necessary. Inter-ethnic differences in its pharmacokinetics are not evident. Owing to inhibition of metabolising enzymes, a small dosage adjustment decrement for nisoldipine CC may be required when it is given in combination with cimetidine. Concomitant ingestion of nisoldipine with grapefruit

  20. Alteration of the intravenous and oral pharmacokinetics of valsartan via the concurrent use of gemfibrozil in rats.

    Science.gov (United States)

    Yang, Seung Jun; Kim, Bong Jin; Mo, Lingxuan; Han, Hyo-Kyung

    2016-07-01

    The present study aimed to examine the potential pharmacokinetic drug interaction between valsartan and gemfibrozil. Compared with the control given valsartan (10 mg/kg) alone, the concurrent use of gemfibrozil (10 mg/kg) significantly (p gemfibrozil, the Cmax and AUC of oral valsartan increased by 1.7- and 2.5-fold, respectively. Consequently, the oral bioavailability of valsartan was significantly higher (p gemfibrozil compared with that of the control group. Furthermore, the intravenous pharmacokinetics of valsartan (1 mg/kg) was also altered by pretreatment with oral gemfibrozil (10 mg/kg). The plasma clearance of valsartan was decreased by two-fold in the presence of gemfibrozil, while the plasma half-life was not altered. In contrast, both the oral and intravenous pharmacokinetics of gemfibrozil were not affected by the concurrent use of valsartan. The cellular uptake of valsartan and gemfibrozil was also investigated by using cells overexpressing OATP1B1 or OATP1B3. Gemfibrozil and gemfibrozil 1-O-β glucuronide inhibited the cellular uptake of valsartan with IC50 values (µm) of 39.3 and 20.4, respectively, in MDCK/OATP1B1, while they were less interactive with OATP1B3. The cellular uptake of gemfibrozil was not affected by co-incubation with valsartan in both cells. Taken together, the present study suggests the potential drug interaction between valsartan and gemfibrozil, at least in part, via the OATP1B1-mediated transport pathways during hepatic uptake. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  1. Population pharmacokinetic model of transdermal nicotine delivered from a matrix-type patch.

    Science.gov (United States)

    Linakis, Matthew W; Rower, Joseph E; Roberts, Jessica K; Miller, Eleanor I; Wilkins, Diana G; Sherwin, Catherine M T

    2017-12-01

    Nicotine addiction is an issue faced by millions of individuals worldwide. As a result, nicotine replacement therapies, such as transdermal nicotine patches, have become widely distributed and used. While the pharmacokinetics of transdermal nicotine have been extensively described using noncompartmental methods, there are few data available describing the between-subject variability in transdermal nicotine pharmacokinetics. The aim of this investigation was to use population pharmacokinetic techniques to describe this variability, particularly as it pertains to the absorption of nicotine from the transdermal patch. A population pharmacokinetic parent-metabolite model was developed using plasma concentrations from 25 participants treated with transdermal nicotine. Covariates tested in this model included: body weight, body mass index, body surface area (calculated using the Mosteller equation) and sex. Nicotine pharmacokinetics were best described with a one-compartment model with absorption based on a Weibull distribution and first-order elimination and a single compartment for the major metabolite, cotinine. Body weight was a significant covariate on apparent volume of distribution of nicotine (exponential scaling factor 1.42). After the inclusion of body weight in the model, no other covariates were significant. This is the first population pharmacokinetic model to describe the absorption and disposition of transdermal nicotine and its metabolism to cotinine and the pharmacokinetic variability between individuals who were administered the patch. © 2017 The British Pharmacological Society.

  2. Pharmacokinetics of mitragynine in man

    Directory of Open Access Journals (Sweden)

    Trakulsrichai S

    2015-04-01

    Full Text Available Satariya Trakulsrichai,1,2 Korbtham Sathirakul,3,4 Saranya Auparakkitanon,5 Jatupon Krongvorakul,5 Jetjamnong Sueajai,5 Nantida Noumjad,5 Chonlaphat Sukasem,5 Winai Wananukul2,6 1Department of Emergency Medicine, Faculty of Medicine Ramathibodi Hospital, 2Ramathibodi Poison Center, Faculty of Medicine Ramathibodi Hospital, 3Department of Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand; 4Center for Drug Research Discovery and Development, Thammasat Univerisity, Prathumthani, Thailand; 5Department of Pathology, Faculty of Medicine Ramathibodi Hospital, 6Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand Background: Kratom, known botanically as Mitragyna speciosa (Korth., is an indigenous tree in Southeast Asia. Kratom is currently easily available worldwide via special shops and the Internet to use as a drug of abuse, opioid alternative, or pain killer. So far, the pharmacokinetics of this plant has been studied only in animals, and there is no such study in humans. The major abundant active alkaloid in Kratom, mitragynine, is one of the promising new chemical substances to be developed as a new drug. The aim of this study was to examine the pharmacokinetics of mitragynine and assess the linearity in pharmacokinetics in chronic users.Methods: Since Kratom is illegal in Thailand, studies in healthy subjects would be unethical. We therefore conducted a prospective study by enrolling ten chronic, regular, healthy users. We adjusted the steady state in each subject by giving a known amount of Kratom tea for 7 days before commencement of the experiment. We admitted and gave different oral doses to subjects to confirm linearity in pharmacokinetics. The mitragynine blood concentrations at 17 times points and the urine concentrations during the 24-hour period were collected and measured by liquid chromatography-tandem mass spectrometry method. Results: Ten male subjects completed

  3. Pharmacokinetics of procaterol in thoroughbred horses.

    Science.gov (United States)

    Kusano, K; Nomura, M; Toju, K; Ishikawa, Y; Minamijima, Y; Yamashita, S; Nagata, S

    2016-06-01

    Procaterol (PCR) is a beta-2-adrenergic bronchodilator widely used in Japanese racehorses for treating lower respiratory disease. The pharmacokinetics of PCR following single intravenous (0.5 μg/kg) and oral (2.0 μg/kg) administrations were investigated in six thoroughbred horses. Plasma and urine concentrations of PCR were measured using liquid chromatography-mass spectrometry. Plasma PCR concentration following intravenous administration showed a biphasic elimination pattern. The systemic clearance was 0.47 ± 0.16 L/h/kg, the steady-state volume of the distribution was 1.21 ± 0.23 L/kg, and the elimination half-life was 2.85 ± 1.35 h. Heart rate rapidly increased after intravenous administration and gradually decreased thereafter. A strong correlation between heart rate and plasma concentration of PCR was observed. Plasma concentrations of PCR after oral administration were not quantifiable in all horses. Urine concentrations of PCR following intravenous and oral administrations were quantified in all horses until 32 h after administration. Urine PCR concentrations were not significantly different on and after 24 h between intravenous and oral administrations. These results suggest that the bioavailability of orally administrated PCR in horses is very poor, and the drug was eliminated from the body slowly based on urinary concentrations. This report is the first study to demonstrate the pharmacokinetic character of PCR in thoroughbred horses. © 2015 John Wiley & Sons Ltd.

  4. Influence of diabetes on the pharmacokinetic behavior of natural polyphenols.

    Science.gov (United States)

    Xiao, Jianbo; Högger, Petra

    2014-01-01

    The development of food fortified with polyphenols and polyphenol-rich foods represents a novel approach to prevent or attenuate type 2 diabetes. It has been reported that type 2 diabetes may affect the pharmacokinetics of various drugs in several animal models. There is powerful evidence linking dietary polyphenols consumption with the risk factors defining type 2 diabetes, even if some opposite results occurred. This mini-review summarizes important advances on diabetes-associated changes in pharmacokinetics of natural polyphenols. The pharmacokinetic behavior between drugs and dietary polyphenols probably may be different due to (i) Ingested dose/amount per day. The dietary polyphenol intake per day is much higher than that of clinical drugs; (ii) Complexity of the components. Clinical drugs are well-characterized and typically small molecules. However, the polyphenols in diet are unimaginably complex; (iii) Interaction with food proteins. Although the effects of food proteins on the bioavailability of polyphenols are still not examined in much detail, direct binding interactions of polyphenols to proteins always occur; (iv) The most common polyphenols in the human diet have a low intrinsic activity and are poorly absorbed from the intestine, highly metabolized, or rapidly eliminated. Although there is very limited information available so far, it is proposed that type 2 diabetes influences the pharmacokinetic behavior of dietary polyphenols including: i) competition of glucose with polyphenols regarding binding to plasma proteins; ii) weakened non-covalent interaction affinities of plasma proteins for natural polyphenols due to protein glycation in type II diabetes; iii) the enhanced clearance of polyphenols in type 2 diabetes. An understanding of diabetes-associated changes in absorption, distribution, metabolism, elimination and bioactivities of natural polyphenols as well as the mechanism of the variability should lead to the improvement of the benefits of

  5. Da-Chaihu-Tang alters the pharmacokinetics of nifedipine in rats and a treatment regimen to avoid this.

    Science.gov (United States)

    He, Ju-Xiu; Ohno, Kenji; Tang, Jun; Hattori, Masao; Tani, Tadato; Akao, Teruaki

    2014-11-01

    To investigate the influence of co-administrated Da-Chaihu-Tang (DCT; a traditional Chinese formulation) on the pharmacokinetics of nifedipine, as well as the safe optimal dosing interval to avoid the adverse interactions. A single dose of DCT was administered with nifedipine simultaneously, 2 h before, 30 min before or 30 min after nifedipine administration. Pharmacokinetics of nifedipine with or without DCT were compared. The influences of DCT on nifedipine intestinal mucosal and hepatic metabolism were studied by using rat in-vitro everted jejunal sac model and hepatic microsomes. A simultaneous co-administration of DCT significantly increased the area under concentration-time curve from time zero to infinity (AUC0-inf ) of nifedipine. In-vitro mechanism investigations revealed that DCT inhibited both the intestinal and the hepatic metabolism of nifedipine. Further study on the optimal dosing interval for nifedipine and DCT revealed that administration of DCT 30 min before or after nifedipine did not significantly change the AUC of nifedipine. The bioavailability of nifedipine is significantly increased by a simultaneous oral co-administration of DCT. This increase is caused by the inhibitory effect of DCT on both the intestinal mucosal and the hepatic metabolism of nifedipine. The dose interval between DCT and nifedipine needs to be set for over 30 min to avoid such drug-drug interactions. © 2014 Royal Pharmaceutical Society.

  6. Th-Based Endohedral Metallofullerenes: Anomalous Metal Position and Significant Metal-Cage Covalent Interactions with the Involvement of Th 5f Orbitals.

    Science.gov (United States)

    Li, Ying; Yang, Le; Liu, Chang; Hou, Qinghua; Jin, Peng; Lu, Xing

    2018-05-29

    Endohedral metallofullerenes (EMFs) containing actinides are rather intriguing due to potential 5f-orbital participation in the metal-metal or metal-cage bonding. In this work, density functional theory calculations first characterized the structure of recently synthesized ThC 74 as Th@ D 3 h (14246)-C 74 . We found that the thorium atom adopts an unusual off-axis position inside cage due to small metal ion size and the requirement of large coordination number, which phenomenon was further extended to other Th-based EMFs. Significantly, besides the strong metal-cage electrostatic attractions, topological and orbital analysis revealed that all the investigated Th-based EMFs exhibit obvious covalent interactions between metal and cage with substantial contribution from the Th 5f orbitals. The encapsulation by fullerenes is thus proposed as a practical pathway toward the f-orbital covalency for thorium. Interestingly, the anomalous internal position of Th led to a novel three-dimensional metal trajectory at elevated temperatures in the D 3 h -C 74 cavity, as elucidated by the static computations and molecular dynamic simulations.

  7. Heritability of metoprolol and torsemide pharmacokinetics

    DEFF Research Database (Denmark)

    Matthaei, Johannes; Brockmöller, Jürgen; Tzvetkov, Mladen

    2015-01-01

    Genetic variation in the pharmacokinetics of metoprolol and torsemide due to polymorphisms in CYP2D6, CYP2C9 and OATP1B1 has been extensively studied. However, it is still unknown how much of variation in pharmacokinetics of these two clinically important drugs in total is due to genetic factors....... of the heritable variability in the pharmacokinetics of metoprolol and torsemide remains to be elucidated. This article is protected by copyright. All rights reserved....

  8. Development of a Pharmacokinetic Model to Describe the Complex Pharmacokinetics of Pazopanib in Cancer Patients

    NARCIS (Netherlands)

    Yu, Huixin; van Erp, Nielka; Bins, Sander; Mathijssen, Ron H J; Schellens, Jan H M; Beijnen, Jos H.; Steeghs, Neeltje; Huitema, Alwin D R

    Background and Objective: Pazopanib is a multi-targeted anticancer tyrosine kinase inhibitor. This study was conducted to develop a population pharmacokinetic (popPK) model describing the complex pharmacokinetics of pazopanib in cancer patients. Methods: Pharmacokinetic data were available from 96

  9. Development of a Pharmacokinetic Model to Describe the Complex Pharmacokinetics of Pazopanib in Cancer Patients

    NARCIS (Netherlands)

    Yu, H.; Erp, N. van; Bins, S.; Mathijssen, R.H.; Schellens, J.H.; Beijnen, J.H.; Steeghs, N.; Huitema, A.D.

    2017-01-01

    BACKGROUND AND OBJECTIVE: Pazopanib is a multi-targeted anticancer tyrosine kinase inhibitor. This study was conducted to develop a population pharmacokinetic (popPK) model describing the complex pharmacokinetics of pazopanib in cancer patients. METHODS: Pharmacokinetic data were available from 96

  10. Pharmacokinetics of drugs in pregnancy.

    Science.gov (United States)

    Feghali, Maisa; Venkataramanan, Raman; Caritis, Steve

    2015-11-01

    Pregnancy is a complex state where changes in maternal physiology have evolved to favor the development and growth of the placenta and the fetus. These adaptations may affect preexisting disease or result in pregnancy-specific disorders. Similarly, variations in physiology may alter the pharmacokinetics or pharmacodynamics that determines drug dosing and effect. It follows that detailed pharmacologic information is required to adjust therapeutic treatment strategies during pregnancy. Understanding both pregnancy physiology and the gestation-specific pharmacology of different agents is necessary to achieve effective treatment and limit maternal and fetal risk. Unfortunately, most drug studies have excluded pregnant women based on often-mistaken concerns regarding fetal risk. Furthermore, over two-thirds of women receive prescription drugs while pregnant, with treatment and dosing strategies based on data from healthy male volunteers and non-pregnant women, and with little adjustment for the complex physiology of pregnancy and its unique disease states. This review will describe basic concepts in pharmacokinetics and their clinical relevance and highlight the variations in pregnancy that may impact the pharmacokinetic properties of medications. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Insights into significant pathways and gene interaction networks underlying breast cancer cell line MCF-7 treated with 17β-estradiol (E2).

    Science.gov (United States)

    Huan, Jinliang; Wang, Lishan; Xing, Li; Qin, Xianju; Feng, Lingbin; Pan, Xiaofeng; Zhu, Ling

    2014-01-01

    Estrogens are known to regulate the proliferation of breast cancer cells and to alter their cytoarchitectural and phenotypic properties, but the gene networks and pathways by which estrogenic hormones regulate these events are only partially understood. We used global gene expression profiling by Affymetrix GeneChip microarray analysis, with KEGG pathway enrichment, PPI network construction, module analysis and text mining methods to identify patterns and time courses of genes that are either stimulated or inhibited by estradiol (E2) in estrogen receptor (ER)-positive MCF-7 human breast cancer cells. Of the genes queried on the Affymetrix Human Genome U133 plus 2.0 microarray, we identified 628 (12h), 852 (24h) and 880 (48 h) differentially expressed genes (DEGs) that showed a robust pattern of regulation by E2. From pathway enrichment analysis, we found out the changes of metabolic pathways of E2 treated samples at each time point. At 12h time point, the changes of metabolic pathways were mainly focused on pathways in cancer, focal adhesion, and chemokine signaling pathway. At 24h time point, the changes were mainly enriched in neuroactive ligand-receptor interaction, cytokine-cytokine receptor interaction and calcium signaling pathway. At 48 h time point, the significant pathways were pathways in cancer, regulation of actin cytoskeleton, cell adhesion molecules (CAMs), axon guidance and ErbB signaling pathway. Of interest, our PPI network analysis and module analysis found that E2 treatment induced enhancement of PRSS23 at the three time points and PRSS23 was in the central position of each module. Text mining results showed that the important genes of DEGs have relationship with signal pathways, such as ERbB pathway (AREG), Wnt pathway (NDP), MAPK pathway (NTRK3, TH), IP3 pathway (TRA@) and some transcript factors (TCF4, MAF). Our studies highlight the diverse gene networks and metabolic and cell regulatory pathways through which E2 operates to achieve its

  12. Effects of andrographolide on the pharmacokinetics of aminophylline and doxofylline in rats.

    Science.gov (United States)

    Li, X P; Zhang, C L; Gao, P; Gao, J; Liu, D

    2013-05-01

    Andrographolide, which is one of the main pharmaceutical ingredients in traditional Chinese medicine Andrographis paniculata, can clear heat, detoxify human body, cool blood and reduce swelling, etc. Respiratory tract infectious diseases have been treated with the combination of andrographolide and theophyllines clinically. As andrographolide inhibits the CYP1A2 activity in vitro, it potentially interacts with theophyllines that are mainly metabolized by CYP1A2. Therefore, we herein studied the effects of andrographolide on the pharmacokinetics of aminophylline and doxofylline in rats. The blood drug concentrations of aminophylline, doxofylline and its metabolite theophylline were determined by HPLC. The theophylline AUC(0-t) was significantly elevated confronting the combination of andrographolide and aminophylline compared to that of the control group (Pandrographolide. The results suggest that andrographolide and aminophylline should not be simultaneously administered because the former may raise the risks of side effects by inhibiting the clearance of the latter. In contrast, it is more secure to combine doxofylline with andrographolide owing to the almost intact pharmacokinetics. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Pharmacokinetic and pharmacodynamic effects of methylphenidate and MDMA administered alone or in combination.

    Science.gov (United States)

    Hysek, Cédric M; Simmler, Linda D; Schillinger, Nathalie; Meyer, Nicole; Schmid, Yasmin; Donzelli, Massimiliano; Grouzmann, Eric; Liechti, Matthias E

    2014-03-01

    Methylphenidate and 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') are widely misused psychoactive drugs. Methylphenidate increases brain dopamine and norepinephrine levels by blocking the presynaptic reuptake transporters. MDMA releases serotonin, dopamine and norepinephrine through the same transporters. Pharmacodynamic interactions of methylphenidate and MDMA are likely. This study compared the pharmacodynamic and pharmacokinetic effects of methylphenidate and MDMA administered alone or in combination in healthy subjects using a double-blind, placebo-controlled, crossover design. Methylphenidate did not enhance the psychotropic effects of MDMA, although it produced psychostimulant effects on its own. The haemodynamic and adverse effects of co-administration of methylphenidate and MDMA were significantly higher compared with MDMA or methylphenidate alone. Methylphenidate did not change the pharmacokinetics of MDMA and vice versa. Methylphenidate and MDMA shared some subjective amphetamine-type effects; however, 125 mg of MDMA increased positive mood more than 60 mg of methylphenidate, and methylphenidate enhanced activity and concentration more than MDMA. Methylphenidate and MDMA differentially altered facial emotion recognition. Methylphenidate enhanced the recognition of sad and fearful faces, whereas MDMA reduced the recognition of negative emotions. Additionally, the present study found acute pharmacodynamic tolerance to MDMA but not methylphenidate. In conclusion, the combined use of methylphenidate and MDMA does not produce more psychoactive effects compared with either drug alone, but potentially enhances cardiovascular and adverse effects. The findings may be of clinical importance for assessing the risks of combined psychostimulant misuse. Trial registration identification number: NCT01465685 (http://clinicaltrials.gov/ct2/show/NCT01465685).

  14. Effect of diclofenac on the pharmacokinetics of moxifloxacin in rats.

    Science.gov (United States)

    Chen, L; Guo, S; Xu, M; Wu, L-X; Zhang, J-H

    2014-07-01

    A sensitive and specific method was developed and validated for the determination of moxifloxacin in plasma using HPLC. The effect of diclofenac (12.5, 25, 50 mg/kg) on the pharmacokinetics of orally administered moxifloxacin (40 mg/kg) in rats was investigated. Pharmacokinetic parameters of moxifloxacin were determined in rats following oral administration to rats in the presence and absence of diclofenac. The coadministration of the 2 drugs resulted in 10~29.5% decrease of the AUC and a 24.7~34% decrease of t1/2 for moxifloxacin; Tmax for moxifloxacin was 1.41~1.9-fold higher than that after the administration of moxifloxacin alone; Cmax for moxifloxacin decreased by 20.5~49%, as compared to that after the administration of moxifloxacin alone. Consequently, moxifloxacin and diclofenac should be monitored closely for potential drug interactions. © Georg Thieme Verlag KG Stuttgart · New York.

  15. Nonstandard Finite Difference Method Applied to a Linear Pharmacokinetics Model

    Directory of Open Access Journals (Sweden)

    Oluwaseun Egbelowo

    2017-05-01

    Full Text Available We extend the nonstandard finite difference method of solution to the study of pharmacokinetic–pharmacodynamic models. Pharmacokinetic (PK models are commonly used to predict drug concentrations that drive controlled intravenous (I.V. transfers (or infusion and oral transfers while pharmacokinetic and pharmacodynamic (PD interaction models are used to provide predictions of drug concentrations affecting the response of these clinical drugs. We structure a nonstandard finite difference (NSFD scheme for the relevant system of equations which models this pharamcokinetic process. We compare the results obtained to standard methods. The scheme is dynamically consistent and reliable in replicating complex dynamic properties of the relevant continuous models for varying step sizes. This study provides assistance in understanding the long-term behavior of the drug in the system, and validation of the efficiency of the nonstandard finite difference scheme as the method of choice.

  16. Localization of aPKC lambda/iota and its interacting protein, Lgl2, is significantly associated with lung adenocarcinoma progression.

    Science.gov (United States)

    Imamura, Naoko; Horikoshi, Yosuke; Matsuzaki, Tomohiko; Toriumi, Kentaro; Kitatani, Kanae; Ogura, Go; Masuda, Ryota; Nakamura, Naoya; Takekoshi, Susumu; Iwazaki, Masayuki

    2013-12-20

    Atypical protein kinase C lambda/iota (aPKC λ/ι) is expressed in several human cancers; however, the correlation between aPKC λ/ι localization and cancer progression in human lung adenocarcinoma (LAC) remains to be clarified. We found that patients with a high level of aPKC λ/ι expression in LAC had significantly shorter overall survival than those with a low level of aPKC λ/ι expression. In addition, localization of aPKC λ/ι in the apical membrane or at the cell-cell contact was associated with both lymphatic invasion and metastasis. The intercellular adhesion molecule, E-cadherin, was decreased in LACs with highly expressed aPKC λ/ι at the invasion site of tumor cells. This result suggested that the expression levels of aPKC λ/ι and E-cadherin reflect the progression of LAC. On double-immunohistochemical analysis, aPKC λ/ι and Lgl2, a protein that interacts with aPKC λ/ι, were co-localized within LACs. Furthermore, we found that Lgl2 bound the aPKC λ/ι-Par6 complex in tumor tissue by immune-cosedimentation analysis. Apical membrane localization of Lgl2 was correlated with lymphatic invasion and lymph node metastasis. These results thus indicate that aPKC λ/ι expression is altered upon the progression of LAC. This is also the first evidence to show aPKC λ/ι overexpression in LAC and demonstrates that aPKC λ/ι localization at the apical membrane or cell-cell contact is associated with lymphatic invasion and metastasis of the tumor.

  17. Gemfibrozil Concentrations are Significantly Decreased in the Presence of Lopinavir/ritonavir

    Science.gov (United States)

    Busse, Kristin H.; Hadigan, Colleen; Chairez, Cheryl; Alfaro, Raul M.; Formentini, Elizabeth; Kovacs, Joseph A.; Penzak, Scott R.

    2009-01-01

    Objective: To determine the influence of a two-week course of lopinavir-ritonavir on the pharmacokinetics of the triglyceride-lowering agent, gemfibrozil. Methods: The study was conducted as an open label, single-sequence pharmacokinetic study in healthy human volunteers. Gemfibrozil pharmacokinetic parameter values were compared using a students t test after a single 600 mg dose was administered to healthy volunteers before, and after two weeks of lopinavir-ritonavir (400/100 mg) twice daily. Results: Fifteen healthy volunteers (8 males) completed the study. All study drugs were generally well-tolerated and no subjects withdrew participation. The geometric mean ratio (GMR, 90% CI) for gemfibrozil area under the plasma concentration-time curve (AUC0-∞) after 14 days of lopinavir-ritonavir compared to baseline was 0.59 (0.52, 0.67) (P gemfibrozil AUC0-∞ after lopinavir-ritonavir (range: −6% to −74%). The GMRs for gemfibrozil apparent oral clearance (Cl/F) and maximum concentration (Cmax) were 1.69 (1.41, 1.97) and 0.67 (0.49, 0.86) after 14 days of lopinavir-ritonavir versus baseline, respectively (P Gemfibrozil elimination half-life did not change after lopinavir-ritonavir administration (P = 0.60). Conclusion: Lopinavir/ritonavir significantly reduced the systemic exposure of gemfibrozil by reducing gemfibrozil absorption. Clinicians treating HIV-infected patients with hypertriglyceridemia should be aware of this drug interaction. PMID:19648824

  18. Gemfibrozil concentrations are significantly decreased in the presence of lopinavir-ritonavir.

    Science.gov (United States)

    Busse, Kristin H; Hadigan, Colleen; Chairez, Cheryl; Alfaro, Raul M; Formentini, Elizabeth; Kovacs, Joseph A; Penzak, Scott R

    2009-10-01

    The objective of this study was to determine the influence of a 2-week course of lopinavir-ritonavir on the pharmacokinetics of the triglyceride-lowering agent, gemfibrozil. The study was conducted as an open label, single-sequence pharmacokinetic study in healthy human volunteers. Gemfibrozil pharmacokinetic parameter values were compared using a Student t test after a single 600-mg dose was administered to healthy volunteers before and after 2 weeks of lopinavir-ritonavir (400/100 mg) twice daily. Fifteen healthy volunteers (eight males) completed the study. All study drugs were generally well tolerated and no subjects withdrew participation. The geometric mean ratio (90% confidence interval) for gemfibrozil area under the plasma concentration-time curve after 14 days of lopinavir-ritonavir compared with baseline was 0.59 (0.52, 0.67) (P gemfibrozil area under the plasma concentration-time curve after lopinavir-ritonavir (range, -6% to -74%). The geometric mean ratios for gemfibrozil apparent oral clearance and maximum concentration were 1.69 (1.41, 1.97) and 0.67 (0.49, 0.86) after 14 days of lopinavir-ritonavir versus baseline, respectively (P Gemfibrozil elimination half-life did not change after lopinavir-ritonavir administration (P = 0.60). Lopinavir-ritonavir significantly reduced the systemic exposure of gemfibrozil by reducing gemfibrozil absorption. Clinicians treating HIV-infected patients with hypertriglyceridemia should be aware of this drug interaction.

  19. Lack of interaction between the peptidomimetic substrates captopril and cephradine.

    Science.gov (United States)

    Foster, David R; Yee, Shiyin; Bleske, Barry E; Carver, Peggy L; Shea, Michael J; Menon, Sujatha S; Ramachandran, Chandrasekharan; Welage, Lynda S; Amidon, Gordon L

    2009-03-01

    Intestinal peptide transporters, including hPEPT1, facilitate the absorption of cephalosporins and angiotensin-converting enzyme inhibitors, and have been investigated as a means to improve oral drug absorption. Renal peptide transporters including hPEPT2, may also facilitate renal reabsorption of such compounds. In vitro and animal studies suggest that co-administration of peptidomimetic compounds may alter oral pharmacokinetics, although this has not been well studied in humans. The purpose of this study was to determine whether co-administration of the hPEPT substrates captopril and cephradine alters the oral pharmacokinetics of either agent. Nine healthy male volunteers received a single oral 25-mg dose of captopril, a single oral 500-mg dose of cephradine, or concurrent ingestion of captopril and cephradine in a cross-over manner. Venous blood samples were taken and captopril and cephradine pharmacokinetics were determined using noncompartmental analyses. No significant differences were observed in captopril or cephradine pharmacokinetics when administered together as compared to each agent alone (a marginal decrease in C(max) was observed for both captopril and cephradine during co-administration [5-15%]; however, differences were not statistically significant). The results of our study suggest that hPEPT1 and hPEPT2 are unlikely to contribute to clinically important drug interactions in humans.

  20. Pharmacokinetics of inhaled anesthetics in green iguanas (Iguana iguana).

    Science.gov (United States)

    Brosnan, Robert J; Pypendop, Bruno H; Barter, Linda S; Hawkins, Michelle G

    2006-10-01

    To test the hypothesis that differences in anesthetic uptake and elimination in iguanas would counter the pharmacokinetic effects of blood:gas solubility and thus serve to minimize kinetic differences among inhaled agents. 6 green iguanas (Iguana iguana). Iguanas were anesthetized with isoflurane, sevoflurane, or desflurane in a Latin-square design. Intervals from initial administration of an anesthetic agent to specific induction events and from cessation of administration of an anesthetic agent to specific recovery events were recorded. End-expired gas concentrations were measured during anesthetic washout. Significant differences were not detected for any induction or recovery events for any inhalation agent in iguanas. Washout curves best fit a 2-compartment model, but slopes for both compartments did not differ significantly among the 3 anesthetics. Differences in blood:gas solubility for isoflurane, sevoflurane, and desflurane did not significantly influence differences in pharmacokinetics for the inhalation agents in iguanas.

  1. Pharmacokinetic considerations and recommendations in palliative care, with focus on morphine, midazolam and haloperidol.

    Science.gov (United States)

    Franken, L G; de Winter, B C M; van Esch, H J; van Zuylen, L; Baar, F P M; Tibboel, D; Mathôt, R A A; van Gelder, T; Koch, B C P

    2016-06-01

    A variety of medications are used for symptom control in palliative care, such as morphine, midazolam and haloperidol. The pharmacokinetics of these drugs may be altered in these patients as a result of physiological changes that occur at the end stage of life. This review gives an overview of how the pharmacokinetics in terminally ill patients may differ from the average population and discusses the effect of terminal illness on each of the four pharmacokinetic processes absorption, distribution, metabolism, and elimination. Specific considerations are also given for three commonly prescribed drugs in palliative care: morphine, midazolam and haloperidol). The pharmacokinetics of drugs in terminally ill patients can be complex and limited evidence exists on guided drug use in this population. To improve the quality of life of these patients, more knowledge and more pharmacokinetic/pharmacodynamics studies in terminally ill patients are needed to develop individualised dosing guidelines. Until then knowledge of pharmacokinetics and the physiological changes that occur in the final days of life can provide a base for dosing adjustments that will improve the quality of life of terminally ill patients. As the interaction of drugs with the physiology of dying is complex, pharmacological treatment is probably best assessed in a multi-disciplinary setting and the advice of a pharmacist, or clinical pharmacologist, is highly recommended.

  2. Food-Drug Interactions

    Directory of Open Access Journals (Sweden)

    Arshad Yar Khan

    2011-03-01

    Full Text Available The effect of drug on a person may be different than expected because that drug interacts with another drug the person is taking (drug-drug interaction, food, beverages, dietary supplements the person is consuming (drug-nutrient/food interaction or another disease the person has (drug-disease interaction. A drug interaction is a situation in which a substance affects the activity of a drug, i.e. the effects are increased or decreased, or they produce a new effect that neither produces on its own. These interactions may occur out of accidental misuse or due to lack of knowledge about the active ingredients involved in the relevant substances. Regarding food-drug interactions physicians and pharmacists recognize that some foods and drugs, when taken simultaneously, can alter the body's ability to utilize a particular food or drug, or cause serious side effects. Clinically significant drug interactions, which pose potential harm to the patient, may result from changes in pharmaceutical, pharmacokinetic, or pharmacodynamic properties. Some may be taken advantage of, to the benefit of patients, but more commonly drug interactions result in adverse drug events. Therefore it is advisable for patients to follow the physician and doctors instructions to obtain maximum benefits with least fooddrug interactions. The literature survey was conducted by extracting data from different review and original articles on general or specific drug interactions with food. This review gives information about various interactions between different foods and drugs and will help physicians and pharmacists prescribe drugs cautiously with only suitable food supplement to get maximum benefit for the patient.

  3. Pharmacokinetics of vinyl chloride in the rat

    International Nuclear Information System (INIS)

    Bolt, H.M.; Laib, R.J.; Kappus, H.; Buchter, A.

    1977-01-01

    When rats are exposed to [ 14 C]vinyl chloride in a closed system, the vinyl chloride present in the atmosphere equilibrates with the animals' organism within 15 min. The course of equilibration could be determined using rats which had been given 6-nitro-1,2,3-benzothiadiazole. This compound completely blocks metabolism of vinyl chloride. The enzymes responsible for metabolism of vinyl chloride are saturated at an atmospheric concentration of vinyl chloride of 250 ppm. Pharmacokinetic analysis shows that no significant cumulation of vinyl chloride or its major metabolites is to be expected on repeated administration of vinyl chlorides. This may be consistent with the theory that a reactive, shortly living metabolite which occurs in low concentration only, may be responsible for the toxic effects of vinyl chloride

  4. Effects of diclofenac on the pharmacokinetics of celastrol in rats and its transport.

    Science.gov (United States)

    Wang, Zengfu; Chen, Dali; Wang, Zhongwei

    2018-12-01

    Diclofenac and celastrol are always used together for the treatment of rheumatoid arthritis; the herb-drug interaction potential between diclofenac and celastrol is still unknown. This study investigates the effects of diclofenac on the pharmacokinetics of celastrol in rats. Twelve male Sprague-Dawley rats were divided into two groups and received celastrol (1 mg/kg) or both celastrol (1 mg/kg) and diclofenac (10 mg/kg) by oral gavage, and blood samples were collected via the oculi chorioideae vein and determined using the LC-MS method developed in this study. Additionally, the effects of diclofenac on the transport of celastrol were investigated using a Caco-2 cell transwell model. Diclofenac could significantly (p diclofenac. These results indicated that diclofenac could decrease the system exposure of celastrol in rats when they are co-administered, and these effects might be exerted via decreasing its absorption in intestine.

  5. Drug Transport and Pharmacokinetics for Chemical Engineers

    Science.gov (United States)

    Simon, Laurent; Kanneganti, Kumud; Kim, Kwang Seok

    2010-01-01

    Experiments in continuous-stirred vessels were proposed to introduce methods in pharmacokinetics and drug transport to chemical engineering students. The activities can be incorporated into the curriculum to illustrate fundamentals learned in the classroom. An appreciation for the role of pharmacokinetics in drug discovery will also be gained…

  6. INTERACT

    DEFF Research Database (Denmark)

    Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD

    This paper considers the impact of visual art and performance on robotics and human-computer interaction and outlines a research project that combines puppetry and live performance with robotics. Kinesics—communication through movement—is the foundation of many theatre and performance traditions ...

  7. Pharmacokinetics and efficacy of intraocular flurbiprofen.

    Science.gov (United States)

    Blazaki, S; Tsika, C; Tzatzarakis, M; Naoumidi, E; Tsatsakis, A; Tsatsanis, C; Tsilimbaris, Miltiadis K

    2017-12-01

    Intravitreal delivery of non-steroidal anti-inflammatory drugs could be an effective way to treat macular edema caused by posterior segment inflammation. In this study, we evaluated the intravitreal bioavailability and anti-inflammatory efficacy of flurbiprofen in rabbit eyes. For pharmacokinetics, 0.1 ml of 7.66 mg/ml flurbiprofen solution was injected intravitreally and vitreous drug levels were analyzed at specific time points using LC-MS technique. For efficacy, 100 ng lipopolysaccharide of E.coli was injected intravitreally in rabbits to induce inflammation. The animals were separated in three groups and received intraocular flurbiprofen, dexamethasone and PBS to serve as control. Complete ocular examination and total cell count in aqueous fluid were determined to evaluate the extent of inflammation. Eyes were then enucleated for histopathology analysis. The efficacy in the uveitis model was determined by clinical signs of inflammation, total leukocyte count and histology findings. No adverse events were observed during pharmacokinetic assessment. No signs of inflammation, hemorrhage or retina detachment were detected. The recovery of flurbiprofen from vitreous samples was 92.6%. The half-life of flurbiprofen was estimated to be 1.92 h with an elimination constant rate (K) of 0.36. Treatment with intraocular injections of flurbiprofen and dexamethasone significantly reduced total leukocyte count in a manner comparable to dexamethasone [reduction of 96.84% (p flurbiprofen injection compared to control eyes. Flurbiprofen is effective in suppressing inflammation in this experimental uveitis model. In our experimental setting, intravitreal flurbiprofen seem to have a therapeutic result comparable to dexamethasone. However, the half-life of the drug remains short, necessitating further research to prolong its presence in the vitreous cavity.

  8. Focus Article: Oscillatory and long-range monotonic exponential decays of electrostatic interactions in ionic liquids and other electrolytes: The significance of dielectric permittivity and renormalized charges

    Science.gov (United States)

    Kjellander, Roland

    2018-05-01

    A unified treatment of oscillatory and monotonic exponential decays of interactions in electrolytes is displayed, which highlights the role of dielectric response of the fluid in terms of renormalized (effective) dielectric permittivity and charges. An exact, but physically transparent statistical mechanical formalism is thereby used, which is presented in a systematic, pedagogical manner. Both the oscillatory and monotonic behaviors are given by an equation for the decay length of screened electrostatic interactions that is very similar to the classical expression for the Debye length. The renormalized dielectric permittivities, which have similar roles for electrolytes as the dielectric constant has for pure polar fluids, consist in general of several entities with different physical meanings. They are connected to dielectric response of the fluid on the same length scale as the decay length of the screened interactions. Only in cases where the decay length is very long, these permittivities correspond approximately to a dielectric response in the long-wavelength limit, like the dielectric constant for polar fluids. Experimentally observed long-range exponentially decaying surface forces are analyzed as well as the oscillatory forces observed for short to intermediate surface separations. Both occur in some ionic liquids and in concentrated as well as very dilute electrolyte solutions. The coexisting modes of decay are in general determined by the bulk properties of the fluid and not by the solvation of the surfaces; in the present cases, they are given by the behavior of the screened Coulomb interaction of the bulk fluid. The surface-fluid interactions influence the amplitudes and signs or phases of the different modes of the decay, but not their decay lengths and wavelengths. The similarities between some ionic liquids and very dilute electrolyte solutions as regards both the long-range monotonic and the oscillatory decays are analyzed.

  9. Pharmacokinetics of Chinese medicines: strategies and perspectives.

    Science.gov (United States)

    Yan, Ru; Yang, Ying; Chen, Yijia

    2018-01-01

    The modernization and internationalization of Chinese medicines (CMs) are hampered by increasing concerns on the safety and the efficacy. Pharmacokinetic (PK) study is indispensable to establish concentration-activity/toxicity relationship and facilitate target identification and new drug discovery from CMs. To cope with tremendous challenges rooted from chemical complexity of CMs, the classic PK strategies have evolved rapidly from PK study focusing on marker/main drug components to PK-PD correlation study adopting metabolomics approaches to characterize associations between disposition of global drug-related components and host metabolic network shifts. However, the majority of PK studies of CMs have adopted the approaches tailored for western medicines and focused on the systemic exposures of drug-related components, most of which were found to be too low to account for the holistic benefits of CMs. With an area under concentration-time curve- or activity-weighted approach, integral PK attempts to understand the PK-PD relevance with the integrated PK profile of multiple co-existing structural analogs (prototyes/metabolites). Cellular PK-PD complements traditional PK-PD when drug targets localize inside the cells, instead of at the surface of cell membrane or extracellular space. Considering the validated clinical benefits of CMs, reverse pharmacology-based reverse PK strategy was proposed to facilitate target identification and new drug discovery. Recently, gut microbiota have demonstrated multifaceted roles in drug efficacy/toxicity. In traditional oral intake, the presystemic interactions of CMs with gut microbiota seem inevitable, which can contribute to the holistic benefits of CMs through biotransforming CMs components, acting as the peripheral target, and regulating host drug disposition. Hence, we propose a global PK-PD approach which includes the presystemic interaction of CMs with gut microbiota and combines omics with physiologically based

  10. Concurrent administration of anticancer chemotherapy drug and herbal medicine on the perspective of pharmacokinetics

    Directory of Open Access Journals (Sweden)

    Yung-Yi Cheng

    2018-04-01

    Full Text Available With an increasing number of cancer patients seeking an improved quality of life, complementary and alternative therapies are becoming more common ways to achieve such improvements. The potential risks of concurrent administration are serious and must be addressed. However, comprehensive evidence for the risks and benefits of combining anticancer drugs with traditional herbs is rare. Pharmacokinetic investigations are an efficient way to understand the influence of concomitant remedies. Therefore, this study aimed to collect the results of pharmacokinetic studies relating to the concurrent use of cancer chemotherapy and complementary and alternative therapies. According to the National Health Insurance (NHI database in Taiwan and several publications, the three most commonly prescribed formulations for cancer patients are Xiang-Sha-Liu-Jun-Zi-Tang, Jia-Wei-Xiao-Yao-San and Bu-Zhong-Yi-Qi-Tang. The three most commonly prescribed single herbs for cancer patients are Hedyotis diffusa, Scutellaria barbata, and Astragalus membranaceus. Few studies have discussed herb–drug interactions involving these herbs from a pharmacokinetics perspective. Here, we reviewed Jia-Wei-Xiao-Yao-San, Long-Dan-Xie-Gan-Tang, Curcuma longa and milk thistle to provide information based on pharmacokinetic evidence for healthcare professionals to use in educating patients about the risks of the concomitant use of various remedies. Keywords: Traditional Chinese medicine, Chemotherapy drug, Pharmacokinetics, Herb–drug interaction

  11. Pharmacokinetics and dosimetry, an introduction

    International Nuclear Information System (INIS)

    Notari, R.E.

    1981-01-01

    Classical pharmacokinetic techniques attempt to quantify the time course for drug in the body by assaying samples of blood or urine as a function of time. The mathematical descriptions that have emerged from this approach have proven extremely valuable to both drug research and drug therapy. Since the monitoring of patients' drug blood levels by obtaining a few small blood samples at key times is clinically practical, individualization of dosage regimens has become a reality. This has dramatically altered certain types of drug therapy. These improvements are limited to cases wherein biological response can be related to drug blood levels since the mathematics are capable only of describing the sampled fluids. Non-sampled fluids are considered as additional compartments or pools and described collectively using kinetic equations for mass balance. This limits progress in those areas of research which require assessment of the relationship of specific organ contents to that of the blood. The author suggests that radiopharmaceutical techniques which can provide the time course in specific organs might be coupled with classical pharmacokinetic approaches to provide insight not previously achieved

  12. A comprehensive physiologically based pharmacokinetic ...

    Science.gov (United States)

    Published physiologically based pharmacokinetic (PBPK) models from peer-reviewed articles are often well-parameterized, thoroughly-vetted, and can be utilized as excellent resources for the construction of models pertaining to related chemicals. Specifically, chemical-specific parameters and in vivo pharmacokinetic data used to calibrate these published models can act as valuable starting points for model development of new chemicals with similar molecular structures. A knowledgebase for published PBPK-related articles was compiled to support PBPK model construction for new chemicals based on their close analogues within the knowledgebase, and a web-based interface was developed to allow users to query those close analogues. A list of 689 unique chemicals and their corresponding 1751 articles was created after analysis of 2,245 PBPK-related articles. For each model, the PMID, chemical name, major metabolites, species, gender, life stages and tissue compartments were extracted from the published articles. PaDEL-Descriptor, a Chemistry Development Kit based software, was used to calculate molecular fingerprints. Tanimoto index was implemented in the user interface as measurement of structural similarity. The utility of the PBPK knowledgebase and web-based user interface was demonstrated using two case studies with ethylbenzene and gefitinib. Our PBPK knowledgebase is a novel tool for ranking chemicals based on similarities to other chemicals associated with existi

  13. Sensitive UHPLC-MS/MS quantitation and pharmacokinetic comparisons of multiple alkaloids from Fuzi- Beimu and single herb aqueous extracts following oral delivery in rats.

    Science.gov (United States)

    Xu, Yanyan; Li, Yamei; Zhang, Pengjie; Yang, Bin; Wu, Huanyu; Guo, Xuejun; Li, Yubo; Zhang, Yanjun

    2017-07-15

    Aconiti Lateralis Radix Praeparata- Fritillariae Thunbergii bulbus, namely Fuzi- Beimu in Chinese, is a classic herb pair whose combined administration was prohibited according to the rule of "Eighteen antagonisms". However, incompatibility of Fuzi and Beimu has become controversial because of the application supported by many recorded ancient prescriptions and increasing modern researches and clinical practice. The present study aimed to investigate the pharmacokinetic differences of multiple alkaloids from Fuzi- Beimu and the single herb aqueous extracts following oral delivery in rats. Twelve alkaloids including aconitine, mesaconitine, hypaconitine, benzoylaconitine, benzoylmesaconitine, benzoylhypacoitine, neoline, fuziline, talatisamine, chasmanine, peimine and peimisine in rat plasma were simultaneously quantitated by using sensitive ultra-high performance liquid chromatography- tandem mass spectrometry (UHPLC-MS/MS), with the method developed and fully validated. Plasma concentrations of the twelve alkaloids after administration were determined and pharmacokinetic parameters were compared. Significant differences were observed for all alkaloids except aconitine, mesaconitine and benzoylaconitine for Fuzi- Beimu group in comparison with the single herb group. AUC 0-t and T 1/2 of hypaconitine were increased significantly. AUC 0-t and C max were increased and T max decreased significantly for benzoylmesaconitine and benzoylhypacoitine. Fuziline showed significantly increased AUC 0-t , C max and T max . T 1/2 of neoline was notably increased. T 1/2 and T max were significantly elevated for talatisamine while C max decreased. T max of chasmanine was significantly increased and C max decreased. Extremely significant increase of T max was found for peimisine, and significant increase of T 1/2 for peimine. Results revealed that combined use of Fuzi and Beimu significantly influenced the system exposure and pharmacokinetic behaviors of multiple alkaloids from both

  14. How do patients actually experience and use art in hospitals? The significance of interaction: a user-oriented experimental case study

    OpenAIRE

    Nielsen, Stine L.; Fich, Lars B.; Roessler, Kirsten K.; Mullins, Michael F.

    2017-01-01

    ABSTRACT This article aims to understand patient wellbeing and satisfaction and to qualify the current guidelines for the application of art in hospitals. Employing anthropological methods, we focus on the interactional aspects of art in health interventions. A user-oriented study ranked 20 paintings, followed by an experiment using paintings in the dayroom of five medical wards. Fieldwork was done over a two-week period. During the first week, dayrooms were configured without the presence of...

  15. Disruption of the 5S RNP-Mdm2 interaction significantly improves the erythroid defect in a mouse model for Diamond-Blackfan anemia.

    Science.gov (United States)

    Jaako, P; Debnath, S; Olsson, K; Zhang, Y; Flygare, J; Lindström, M S; Bryder, D; Karlsson, S

    2015-11-01

    Diamond-Blackfan anemia (DBA) is a congenital erythroid hypoplasia caused by haploinsufficiency of genes encoding ribosomal proteins (RPs). Perturbed ribosome biogenesis in DBA has been shown to induce a p53-mediated ribosomal stress response. However, the mechanisms of p53 activation and its relevance for the erythroid defect remain elusive. Previous studies have indicated that activation of p53 is caused by the inhibition of mouse double minute 2 (Mdm2), the main negative regulator of p53, by the 5S ribonucleoprotein particle (RNP). Meanwhile, it is not clear whether this mechanism solely mediates the p53-dependent component found in DBA. To approach this question, we crossed our mouse model for RPS19-deficient DBA with Mdm2(C305F) knock-in mice that have a disrupted 5S RNP-Mdm2 interaction. Upon induction of the Rps19 deficiency, Mdm2(C305F) reversed the p53 response and improved expansion of hematopoietic progenitors in vitro, and ameliorated the anemia in vivo. Unexpectedly, disruption of the 5S RNP-Mdm2 interaction also led to selective defect in erythropoiesis. Our findings highlight the sensitivity of erythroid progenitor cells to aberrations in p53 homeostasis mediated by the 5S RNP-Mdm2 interaction. Finally, we provide evidence indicating that physiological activation of the 5S RNP-Mdm2-p53 pathway may contribute to functional decline of the hematopoietic system in a cell-autonomous manner over time.

  16. Modeling of corneal and retinal pharmacokinetics after periocular drug administration.

    Science.gov (United States)

    Amrite, Aniruddha C; Edelhauser, Henry F; Kompella, Uday B

    2008-01-01

    the SD rat corneas. Similar pharmacokinetics models explain drug delivery to the cornea in rat and rabbit animal models. Retinal pharmacokinetics after periocular drug administration can be explained with a four-compartment (periocular space, choroid-containing transfer compartment, retina, and distribution compartment) model with elimination from the periocular space, retina, and choroid compartment. Inclusion of a dissolution-release step before the drug is available for absorption or elimination better explains retinal t(max). Good fits were obtained in both the BN (r = 0.99) and SD (r = 0.99) rats for retinal celecoxib using the same model; however, the parameter estimates differed. Corneal and retinal pharmacokinetics of small lipophilic molecules after periocular administration can be described by compartment models. The modeling analysis shows that (1) leak-back from the site of administration most likely contributes to the apparent lack of an increase phase in corneal concentrations; (2) elimination via the conjunctival or periocular blood and lymphatic systems contributes significantly to drug clearance after periocular injection; (3) corneal pharmacokinetics of small lipophilic molecules can be explained by using similar models in rats and rabbits; and (4) although there are differences in some retinal pharmacokinetics parameters between the pigmented and nonpigmented rats, the physiological basis of these differences has yet to be ascertained.

  17. Evaluation of pharmacokinetics underlies the collaborated usage of lamivudine and oxymatrine in beagle dogs

    Directory of Open Access Journals (Sweden)

    Zhenbao Li

    2016-10-01

    Full Text Available Combinational therapy of lamivudine and oxymatrine has been employed in the battle against hepatitis B virus in clinical setting. However, the pharmacokinetic behavior of the drug or active metabolism in intravenous/oral co-administration regime is poorly investigated. Herein, we evaluated the pharmacokinetic characteristic through a tailor-designed 3 way crossover-Latin square experiment in adult male beagle dogs. Six dogs were randomly treated by intravenous administration of lamivudine (2.5 mg/kg, oxymatrine (15 mg/kg and combinational dosage, named as intravenous regime. Meanwhile the other six dogs were orally administrated with lamivudine (2.5 mg/kg, oxymatrine (15 mg/kg and combinational dosage, named as oral regime. The pharmacokinetic feature in simultaneous oral treatment appeared to have no significant difference when compared with individual administration, even including matrine, the active metabolite of oxymatrine. In intravenous regime, the main pharmacokinetic parameters of simultaneous administration were nearly consistent with intravenous regime remedy. The collaborated application of lamivudine and oxymatrine contributed to non-distinctive pharmacokinetic fluctuations of beagle dogs in intravenous/oral regime, compared with individual employment, which established a vital base for the clinical co-administration against hepatitis B. Furthermore, the present study demonstrated that the determination of pharmacokinetics between combinational and individual therapy might assist in the development of drug compatibility in clinical therapy.

  18. Vascular input function correction of inflow enhancement for improved pharmacokinetic modeling of liver DCE-MRI.

    Science.gov (United States)

    Ning, Jia; Schubert, Tilman; Johnson, Kevin M; Roldán-Alzate, Alejandro; Chen, Huijun; Yuan, Chun; Reeder, Scott B

    2018-06-01

    To propose a simple method to correct vascular input function (VIF) due to inflow effects and to test whether the proposed method can provide more accurate VIFs for improved pharmacokinetic modeling. A spoiled gradient echo sequence-based inflow quantification and contrast agent concentration correction method was proposed. Simulations were conducted to illustrate improvement in the accuracy of VIF estimation and pharmacokinetic fitting. Animal studies with dynamic contrast-enhanced MR scans were conducted before, 1 week after, and 2 weeks after portal vein embolization (PVE) was performed in the left portal circulation of pigs. The proposed method was applied to correct the VIFs for model fitting. Pharmacokinetic parameters fitted using corrected and uncorrected VIFs were compared between different lobes and visits. Simulation results demonstrated that the proposed method can improve accuracy of VIF estimation and pharmacokinetic fitting. In animal study results, pharmacokinetic fitting using corrected VIFs demonstrated changes in perfusion consistent with changes expected after PVE, whereas the perfusion estimates derived by uncorrected VIFs showed no significant changes. The proposed correction method improves accuracy of VIFs and therefore provides more precise pharmacokinetic fitting. This method may be promising in improving the reliability of perfusion quantification. Magn Reson Med 79:3093-3102, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  19. Computational Analysis of Pharmacokinetic Behavior of Ampicillin

    Directory of Open Access Journals (Sweden)

    Mária Ďurišová

    2016-07-01

    Full Text Available orrespondence: Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, 841 04 Bratislava, Slovak Republic. Phone + 42-1254775928; Fax +421254775928; E-mail: maria.durisova@savba.sk 84 RESEARCH ARTICLE The objective of this study was to perform a computational analysis of the pharmacokinetic behavior of ampicillin, using data from the literature. A method based on the theory of dynamic systems was used for modeling purposes. The method used has been introduced to pharmacokinetics with the aim to contribute to the knowledge base in pharmacokinetics by including the modeling method which enables researchers to develop mathematical models of various pharmacokinetic processes in an identical way, using identical model structures. A few examples of a successful use of the modeling method considered here in pharmacokinetics can be found in full texts articles available free of charge at the website of the author, and in the example given in the this study. The modeling method employed in this study can be used to develop a mathematical model of the pharmacokinetic behavior of any drug, under the condition that the pharmacokinetic behavior of the drug under study can be at least partially approximated using linear models.

  20. Pharmacokinetic compatibility of ginsenosides and Schisandra Lignans in Shengmai-san: from the perspective of p-glycoprotein.

    Directory of Open Access Journals (Sweden)

    Yan Liang

    Full Text Available Phytochemical-mediated alterations in P-glycoprotein (P-gp activity may result in herb-drug interactions by altering drug pharmacokinetics. Shengmai-san, a traditional Chinese herbal medicine composed by Panax Ginseng, Ophiopogon Japonicus, and Schisandra Chinensis, is routinely being used for treating various coronary heart diseases. In our previous studies, Schisandra Lignans Extract (SLE was proved as a strong P-gp inhibitor, and herein, the compatibility of Shengmai-san was studied by investigating the influence of SLE on the pharmacokinetics of the ginsenosides from the perspective of P-gp.Pharmacokinetic experiments were firstly performed based on in vitro uptake, efflux and transport experiments in Caco-2, LLC-PK1 wild-type and MDR1-overexpressing L-MDR1 cells. During the whole experiment, digoxin, a classical P-gp substrate, was used as a positive control drug to verify the cells used are the valid models. Meanwhile, the effects of SLE on the pharmacokinetics of ginsenosides were further investigated in rats after single-dose and multi-dose of SLE.The efflux ratios of ginsenoside Rb2, Rc, Rg2, Rg3, Rd and Rb1 were found more than 3.5 in L-MDR1 cells and can be decreased significantly by verapamil (a classical P-gp inhibitor. Contrarily, the efflux ratios of other ginsenosides (Rh1, F1, Re, and Rg1 were lower than 2.0 and not affected by verapamil. Then, the effects of SLE on the uptake and transport of ginsenosides were investigated, and SLE was found can significantly enhance the uptake and inhibit the efflux ratio of ginsenoside Rb2, Rc, Rg2, Rg3, Rd and Rb1 in Caco-2 and L-MDR1 cells. Besides, In vivo experiments showed that single-dose and multi-dose of SLE at 500 mg/kg could increase the area under the plasma concentration time curve of Rb2, Rc and Rd significantly without affecting terminal elimination half-time. In conclusion, SLE could enhance the exposure of ginsenosides Rb2, Rc, Rg2, Rg3, Rd and Rb1 significantly.

  1. Pharmacokinetics of amikacin during hemodialysis and peritoneal dialysis

    DEFF Research Database (Denmark)

    Regeur, L; Colding, H; Jensen, H

    1977-01-01

    The pharmacokinetics of amikacin were examined in six bilaterally nephrectomized patients undergoing hemodialysis and in four patients with a minimal residual renal function undergoing peritoneal dialysis. The mean elimination half-life before the dialysis was 86.5 h in the anephric patients and 44...... renal function. During hemodialysis the half-life decreased to less than 10% (5.6 h) of the pretreatment value. The effectiveness of peritoneal dialysis was less as the half-life decreased to only about 30% (17.9 h) of the pretreatment value. During the dialyses a significant correlation between...... the half-life of amikacin and the decrease in blood urea and serum creatinine was demonstrated. The pharmacokinetic data were used to make dosage regimen recommendations for the treatment of patients undergoing intermittent hemodialysis or peritoneal dialysis....

  2. Exposure-safety and efficacy response relationships and population pharmacokinetics of eslicarbazepine acetate.

    Science.gov (United States)

    Gidal, B E; Jacobson, M P; Ben-Menachem, E; Carreño, M; Blum, D; Soares-da-Silva, P; Falcão, A; Rocha, F; Moreira, J; Grinnell, T; Ludwig, E; Fiedler-Kelly, J; Passarell, J; Sunkaraneni, S

    2018-05-06

    Eslicarbazepine acetate (ESL) is a once-daily (QD) oral antiepileptic drug (AED) for focal-onset seizures (FOS). Pharmacokinetic (PK) and pharmacodynamic (PD) models were developed to assess dose selection, identify significant AED drug interactions, and quantitate relationships between exposure and safety and efficacy outcomes from Phase 3 trials of adjunctive ESL. Eslicarbazepine (the primary active metabolite of ESL) population PK was evaluated using data from 1351 subjects enrolled in 14 studies (11 Phase 1 and three Phase 3 studies) after multiple oral doses ranging from 400 to 1200 mg. Population PK and PD models related individual eslicarbazepine exposures to safety outcomes and efficacy responses. Eslicarbazepine PK was described by a one-compartment model with linear absorption and elimination. The probability of a treatment-emergent adverse event (TEAE; dizziness, headache, or somnolence) was higher with an initial dose of ESL 800 mg than with an initial dose of ESL 400 mg QD. Body weight, sex, region, and baseline use of carbamazepine (CBZ) or lamotrigine were also found to influence the probability of TEAEs. Eslicarbazepine exposure influenced serum sodium concentration, standardized seizure frequency, and probability of response; better efficacy outcomes were predicted in patients not from Western Europe (WE; vs WE patients) and those not taking CBZ (vs taking CBZ) at baseline. Pharmacokinetic and PK/PD modeling were implemented during the development of ESL for adjunctive treatment of FOS in adults. This quantitative approach supported decision-making during the development of ESL, and contributed to dosing recommendations and labeling information related to drug interactions. © 2018 The Authors. Acta Neurologica Scandinavica Published by John Wiley & Sons Ltd.

  3. Effect of Semaglutide on the Pharmacokinetics of Metformin, Warfarin, Atorvastatin and Digoxin in Healthy Subjects.

    Science.gov (United States)

    Hausner, Helene; Derving Karsbøl, Julie; Holst, Anders G; Jacobsen, Jacob B; Wagner, Frank-Dietrich; Golor, Georg; Anderson, Thomas W

    2017-11-01

    Semaglutide is a glucagon-like peptide-1 analogue in development for the once-weekly treatment of type 2 diabetes mellitus. Its effect on the rate and extent of absorption of concomitant oral medications (metformin, warfarin, atorvastatin and digoxin) was evaluated in healthy subjects. Subjects received metformin (500 mg twice daily for 3.5 days), warfarin (25 mg, single dose), atorvastatin (40 mg, single dose) or digoxin (0.5 mg, single dose) before and with subcutaneous semaglutide treatment at steady state (1.0 mg). Lack of drug-drug interaction was concluded if the 90% confidence intervals for the area under the plasma concentration-time curve ratio before and with semaglutide were within a pre-specified interval (0.80-1.25). Overall, metformin, warfarin, atorvastatin and digoxin pharmacokinetics were not affected to a clinically relevant degree with semaglutide co-administration. Estimated area under the plasma concentration-time curve ratios for all concomitant medications before and with semaglutide treatment were within the pre-specified interval. In addition, semaglutide did not affect maximum plasma concentration of concomitant medications to a relevant degree. Furthermore, no clinically relevant change in international normalised ratio response to warfarin was observed with semaglutide co-administration. Most adverse events with semaglutide treatment were mild or moderate. Adverse events with semaglutide and co-administered medication were comparable to those reported during treatment with semaglutide alone, and were mostly gastrointestinal related. No clinically significant pharmacokinetic or pharmacodynamic interactions were identified and no new safety issues observed with combined treatment with semaglutide. This suggests that no dose adjustments should be required when semaglutide is administered concomitantly with these medications.

  4. Characterization of the pharmacokinetics of gasoline using PBPK modeling with a complex mixtures chemical lumping approach.

    Science.gov (United States)

    Dennison, James E; Andersen, Melvin E; Yang, Raymond S H

    2003-09-01

    Gasoline consists of a few toxicologically significant components and a large number of other hydrocarbons in a complex mixture. By using an integrated, physiologically based pharmacokinetic (PBPK) modeling and lumping approach, we have developed a method for characterizing the pharmacokinetics (PKs) of gasoline in rats. The PBPK model tracks selected target components (benzene, toluene, ethylbenzene, o-xylene [BTEX], and n-hexane) and a lumped chemical group representing all nontarget components, with competitive metabolic inhibition between all target compounds and the lumped chemical. PK data was acquired by performing gas uptake PK studies with male F344 rats in a closed chamber. Chamber air samples were analyzed every 10-20 min by gas chromatography/flame ionization detection and all nontarget chemicals were co-integrated. A four-compartment PBPK model with metabolic interactions was constructed using the BTEX, n-hexane, and lumped chemical data. Target chemical kinetic parameters were refined by studies with either the single chemical alone or with all five chemicals together. o-Xylene, at high concentrations, decreased alveolar ventilation, consistent with respiratory irritation. A six-chemical interaction model with the lumped chemical group was used to estimate lumped chemical partitioning and metabolic parameters for a winter blend of gasoline with methyl t-butyl ether and a summer blend without any oxygenate. Computer simulation results from this model matched well with experimental data from single chemical, five-chemical mixture, and the two blends of gasoline. The PBPK model analysis indicated that metabolism of individual components was inhibited up to 27% during the 6-h gas uptake experiments of gasoline exposures.

  5. Effect of Resveratrol Treatment on the Pharmacokinetics of Diclofenac in Healthy Human Volunteers.

    Science.gov (United States)

    Bedada, Satish Kumar; Yellu, Narsimha Reddy; Neerati, Prasad

    2016-03-01

    The purpose of the present study was to assess the effect of resveratrol (RSV) treatment on the pharmacokinetics of diclofenac (DIC) in healthy human volunteers. The open-label, two period, sequential study was conducted in 12 healthy human volunteers. A single dose of RSV 500 mg was administered daily for 10 days during treatment phase. A single dose of DIC 100 mg was administered during control and after treatment phases under fasting conditions. The blood samples were collected after DIC dosing and analyzed by HPLC. Treatment with RSV significantly enhanced maximum plasma concentration (Cmax) (1.73 to 2.91 µg/mL), area under the curve (AUC) (5.05 to 9.95 g h/mL), half life (T1/2) (1.12 to 1.76 h) and significantly decreased elimination rate constant (Kel ) (0.71 to 0.41 h(-1)), apparent oral clearance (CL/F) (14.58 to 6.48 L/h) of DIC as compared to control. The geometric mean ratios for Cmax, AUC, T1/2, Kel and CL/F of DIC were 1.75, 2.12, 1.65, 0.61 and 0.47, respectively were outside the limits of 0.8-1.25, which indicates clinically significant interaction between DIC and RSV. The results suggest that the altered pharmacokinetics of DIC might be attributed to RSV mediated inhibition of CYP2C9 enzyme. Therefore, combination therapy of DIC along with RSV may represent a novel approach to reduce dosage and results in reduced gastrointestinal side effects of DIC. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Effect of mushroom diet on pharmacokinetics of gabapentin in healthy Chinese subjects.

    Science.gov (United States)

    Toh, Dorothy Su Lin; Limenta, Lie Michael George; Yee, Jie Yin; Wang, Ling-Zhi; Goh, Boon-Cher; Murray, Michael; Lee, Edmund Jon Deoon

    2014-07-01

    This study evaluated the pharmacokinetics of gabapentin in Chinese subjects who received a diet rich in shiitake mushrooms. Shiitake mushrooms have been shown to contain high amount of ergothioneine. In vitro studies have shown that OCTN1-mediated secretion of gabapentin is trans-stimulated by ergothioneine. This study also investigated the concentrations of ergothioneine in plasma at baseline and following mushroom consumption. Ten healthy male subjects were recruited and received a diet containing no mushrooms (treatment A) or a high mushroom diet (treatment B; after at least a 7 day washout period) 1 day prior to administration of a single oral dose of gabapentin 600 mg. Ingestion of shiitake mushrooms produced significant increases in plasma ergothioneine concentrations that were sustained for more than 48 h. A statistically significant but modest increase in the renal clearance (CLR ) of gabapentin occurred after intake of the mushroom diet (91.1 ± 25.1 vs. 76.9 ± 20.6 ml min(-1) , P = 0.031). No significant changes in AUC(0,tlast ) of gabapentin were observed (P = 0.726). Creatinine clearance did not correlate with CLR of gabapentin at baseline (treatment A). After ingestion of the mushroom diet, creatinine clearance accounted for 65.3% of the variance in CLR of gabapentin. These data suggest that diet-drug pharmacokinetic interactions may occur during co-exposure to gabapentin and mushroom constituents. However, as it does not affect the AUC(0,tlast ) of gabapentin, it may not have clinically important consequences. Shiitake mushrooms can also be used as a source of ergothioneine for future clinical studies. © 2013 The British Pharmacological Society.

  7. Effects of etravirine on the pharmacokinetics and pharmacodynamics of warfarin in rats

    Science.gov (United States)

    John, J; John, M; Wu, L; Hsiao, C; Abobo, CV; Liang, D

    2013-01-01

    Background and Purpose Warfarin is often used with etravirine (ETV) to prevent HIV-related thromboembolic events. As both warfarin and ETV bind to plasma proteins and are metabolized by hepatic cytochrome P450s, they are likely to interact. Hence, we evaluated the effect of ETV on the pharmacokinetics and blood clotting time of racemic warfarin in rats. Experimental Approach Two groups of male Sprague-Dawley rats, in which the jugular vein had been cannulated, were studied. The control group (n = 10) received 1 mg·kg−1 racemic warfarin i.v., and the test group (n = 13) 1 mg·kg−1 of racemic warfarin followed by 25 mg·kg−1 ETV i.v. Serial blood samples were collected for up to 144 h and the blood clotting time (calculated as international normalized ratio [INR]) measured in blood plasma at each sample point. Plasma concentrations of R-warfarin, S-warfarin, R-7-hydroxywarfarin and S-7-hydroxywarfarin were measured by a LC/MS/MS method using a chiral lux cellulose-1 column. Pharmacokinetic parameters were analysed using non-compartmental methods. Key Results ETV significantly increased, by threefold, the systemic clearance and volume of distribution of S-warfarin, but not those of R-warfarin. ETV decreased the total AUC of warfarin, but had no effect on its elimination half-life. ETV also increased the systemic clearance of both R-7-hydroxywarfarin and S-7-hydroxywarfarin but only increased the volume of distribution of R-7-hydroxywarfarin. Interestingly, the effect of warfarin on blood clotting time (INR) was significantly increased in the presence of etravirine. Conclusion and Implications Our data suggest that etravirine may potentiate the anticoagulant effect of warfarin and this could have clinical significance. PMID:23215758

  8. Triprotic acid-base microequilibria and pharmacokinetic sequelae of cetirizine.

    Science.gov (United States)

    Marosi, Attila; Kovács, Zsuzsanna; Béni, Szabolcs; Kökösi, József; Noszál, Béla

    2009-06-28

    (1)H NMR-pH titrations of cetirizine, the widely used antihistamine and four related compounds were carried out and the related 11 macroscopic protonation constants were determined. The interactivity parameter between the two piperazine amine groups was obtained from two symmetric piperazine derivatives. Combining these two types of datasets, all the 12 microconstants and derived tautomeric constants of cetirizine were calculated. Upon this basis, the conflicting literature data of cetirizine microspeciation were clarified, and the pharmacokinetic absorption-distribution properties could be interpreted. The pH-dependent distribution of the microspecies is provided.

  9. Influence of hydralazine on the pharmacokinetics of orally administered d-propranolol and lidocaine in conscious dogs.

    Science.gov (United States)

    Heinzow, B G; Somogyi, A; McLean, A J

    1987-03-01

    A study was conducted on the influence of oral coadministration of hydralazine (H) on the pharmacokinetics of d-propranolol (P) and lidocaine (L) in 6 conscious dogs. They were given an oral solution containing P (2 mg/kg) and L (15 mg/kg) alone or together with 25 mg H. Plasma concentrations of P and L and the metabolites monoethylglycinexylidide (MEGX) and glycinexylidide (GX) were measured by specific HPLC methods. Concomitant administration of H caused a significant (p less than 0.05) increase in P peak concentrations (Cmax, 34 +/- 5: 73 +/- 10 ng/ml) and the area under plasma concentration time curve (AUC, 142 +/- 18: 254 +/- 56 ng/ml X hr) of P with significant (p less than 0.05) 24% reduction of the apparent oral clearance. The time to reach peak concentrations (Tmax) and the terminal half life (t1/2 beta) were not altered. In contrast to the pattern seen with P the disposition of L was not affected by H. The change in presystemic clearance of P by H cannot be explained by a general underlying mechanism such as an alteration in liver blood flow alone or portal-systemic shunting, since then the pharmacokinetics of L should parallel those of P. It is speculated that other mechanisms, most likely alteration of P metabolism, are primarily responsible for the observed interaction between P and H.

  10. Food-drug interactions

    DEFF Research Database (Denmark)

    Schmidt, Lars E; Dalhoff, Kim

    2002-01-01

    Interactions between food and drugs may inadvertently reduce or increase the drug effect. The majority of clinically relevant food-drug interactions are caused by food-induced changes in the bioavailability of the drug. Since the bioavailability and clinical effect of most drugs are correlated......, the bioavailability is an important pharmacokinetic effect parameter. However, in order to evaluate the clinical relevance of a food-drug interaction, the impact of food intake on the clinical effect of the drug has to be quantified as well. As a result of quality review in healthcare systems, healthcare providers...... are increasingly required to develop methods for identifying and preventing adverse food-drug interactions. In this review of original literature, we have tried to provide both pharmacokinetic and clinical effect parameters of clinically relevant food-drug interactions. The most important interactions are those...

  11. Pharmacokinetics of thiamphenicol in dogs.

    Science.gov (United States)

    Castells, G; Intorre, L; Franquelo, C; Cristòfol, C; Pérez, B; Martí, G; Arboix, M

    1998-11-01

    To determine pharmacokinetic parameters of thiamphenicol (TAP) after IV and IM administration in dogs. 6 healthy 2- to 3-year-old male Beagles. IN a crossover design study, 3 dogs were given TAP IV, and 3 dogs were given TAP IM, each at a dosage of 40 mg/kg of body weight. Three weeks later, the same dogs were given a second dose by the opposite route. At preestablished times after TAP administration, blood samples were collected through a catheter placed in the cephalic vein, and TAP concentration was determined by use of a high-performance liquid chromatography. Results-Kinetics of TAP administered IV were fitted by a biexponential equation with a rapid first disposition phase followed by a slower disposition phase. Elimination half-life was short (1.7+/-0.3 hours), volume of distribution at steady state was 0.66+/-0.05 L/kg, and plasma clearance was 5.3+/-0.7 ml/min/kg. After IM administration, absorption was rapid. Peak plasma concentration (25.1+/-10.3 microg/ml) was reached about 45 minutes after drug administration. The apparent elimination half-life after IM administration (5.6+/-4.6 hours) was longer than that after IV administration probably because of the slow absorption rate from the muscle. Mean bioavailability after IM administration was 96+/-7%. The pharmacokinetic profile of TAP in dogs suggests that it may be therapeutically useful against susceptible microorganisms involved in the most common infections in dogs, such as tracheobronchitis, enterocolitis, mastitis, and urinary tract infections.

  12. [Pharmacokinetics of crocetin in rats].

    Science.gov (United States)

    Liu, Tong-zheng; Qian, Zhi-yu

    2002-05-01

    To develop an HPLC method for the determination of crocetin in rat plasma and study the pharmacokinetics in rats. Hypersil C18 column (5 microns, 4.6 mm x 200 mm) was used at column temperature 30 degrees C. The mobile phase consisted of methanol-water-acetic acid (75:24.5:0.5) at the flow rate of 1.0 mL.min-1. The UV detection wave length was 423 nm. The calibration curve was linear (gamma = 0.9996) in the range from 0.49 microgram.mL-1 to 7.87 micrograms.mL-1 for crocetin. The mean recovery was 105.2%. The lowest detectable concentration of crocetin was 0.14 microgram.mL-1 (S/N = 3). The RSDs of within-day and between-day were all less than 5%. The plasma crocetin was steady. The HPLC method of determination of crocetin in the plasma was established. After single dose of 50 mg.kg-1 ig in 10 rats, the main pharmacokinetic parameters were estimated as follows: T1/2 alpha (30 +/- 6) min, Tmax(65 +/- 16) min, Cmax(5.0 +/- 1.0) microgram.mL-1, AUC0-T(845 +/- 109) microgram.min.mL-1, Vd(5.0 +/- 0.8) L.kg-1. Crocetin was shown to be absorbed into the blood through the gastrointestinal tract. This method is quick, precise and reliable. Crocetin was shown to be quickly absorbed in rats.

  13. Pharmacokinetics of Intravenous Posaconazole in Critically Ill Patients.

    Science.gov (United States)

    Sime, Fekade B; Stuart, Janine; Butler, Jenie; Starr, Therese; Wallis, Steven C; Pandey, Saurabh; Lipman, Jeffrey; Roberts, Jason A

    2018-06-01

    To date, there is no information on the intravenous (i.v.) posaconazole pharmacokinetics for intensive care unit (ICU) patients. This prospective observational study aimed to describe the pharmacokinetics of a single dose of i.v. posaconazole in critically ill patients. Patients with no history of allergy to triazole antifungals and requiring systemic antifungal therapy were enrolled if they were aged ≥18 years, central venous access was available, they were not pregnant, and they had not received prior posaconazole or drugs interacting with posaconazole. A single dose of 300 mg posaconazole was administered over 90 min. Total plasma concentrations were measured from serial plasma samples collected over 48 h, using a validated chromatographic method. The pharmacokinetic data set was analyzed by noncompartmental methods. Eight patients (7 male) were enrolled with the following characteristics: median age, 46 years (interquartile range [IQR], 40 to 51 years); median weight, 68 kg (IQR, 65 to 82 kg); and median albumin concentration, 20 g/liter (IQR, 18 to 24 g/liter). Median (IQR) pharmacokinetic parameter estimates were as follows: observed maximum concentration during sampling period ( C max ), 1,702 ng/ml (1,352 to 2,141 ng/ml); area under the concentration-time curve from zero to infinity (AUC 0-∞ ), 17,932 ng · h/ml (13,823 to 27,905 ng · h/ml); clearance (CL), 16.8 liters/h (11.1 to 21.7 liters/h); and volume of distribution ( V ), 529.1 liters (352.2 to 720.6 liters). The V and CL were greater than 2-fold and the AUC 0-∞ was 39% of the values reported for heathy volunteers. The AUC 0-∞ was only 52% of the steady-state AUC 0-24 reported for hematology patients. The median of estimated average steady-state concentrations was 747 ng/ml (IQR, 576 to 1,163 ng/ml), which is within but close to the lower end of the previously recommended therapeutic range of 500 to 2,500 ng/ml. In conclusion, we observed different pharmacokinetics of i.v. posaconazole in

  14. Glipizide Pharmacokinetics in Healthy and Diabetic Volunteers

    African Journals Online (AJOL)

    Erah

    Purpose: Disease state may contribute to alteration in drug pharmacokinetics. The purpose of .... dependency or drug abuse, known allergy to ... HPLC analysis of glipizide ... months when stored at 4 0C, protected from .... plasma and urine.

  15. Pharmacokinetics of lysine clonixinate in children in postoperative care.

    Science.gov (United States)

    González-Martin, G; Cattan, C; Zuñiga, S

    1996-09-01

    The pharmacokinetics of 2 doses of intravenous lysine clonixinate (4 and 6 mg x kg-1) were studied in 10 children (age 4-10 years) under postoperative care. A single dose of the drug was injected in a forearm vein. Blood samples were collected at regular intervals for 3 hours. Serum clonixin concentrations (expressed as clonixin) were analyzed using a high pressure liquid chromatography method. Pharmacokinetic values were estimated by a nonlinear computer program. The distribution volume was similar in both groups of children (1.288 +/- 0.829 1 and 1. 139 +/- 0.667 1, respectively). There were no differences between the values of total plasma clearance and the administered doses (0.026 +/- 0.017 ml x min-1 and 0.017 +/- 0.008 ml x min-1, t = 1.07, p = 0.76). The elimination half-life was longer in children who received 6 mg x kg-1 (44.26 +/- 6.34 min vs 38.63 +/- 10.93 min) but this difference was not statistically significant (t = 0.99, p < 0.34). The pharmacokinetic parameters calculated in these children were different from those found by other authors in adults and experimental animals.

  16. Effect of the menstrual cycle in ethanol pharmacokinetics.

    Science.gov (United States)

    Haddad, L; Milke, P; Zapata, L; de la Fuente, J R; Vargas-Vorácková, F; Lorenzana-Jiménez, M; Corte, G; Tamayo, J; Kaplan, M; Márquez, M; Kershenobich, D

    1998-01-01

    Differences in ethanol pharmacokinetics within the menstrual cycle have previously been reported and attributed to variations in body composition, hormonal influences and gastric emptying. To establish the role of the menstrual cycle in ethanol pharmacokinetics associated with changes in body composition, ethanol blood concentrations were measured in nine healthy women during the midfollicular (P1, days 8-10) and midluteal (P2, days 22-24) phases of the menstrual cycle after a postprandial oral ethanol dose (0.3 g kg(-1)). Total body water was assessed by dual-energy x-ray densitometry (DEXA) on both occasions. Median total body water did not vary during either phase of the menstrual cycle (P1 = 54.54%, P2 = 54.66%; P = 0.9296). Median area under the ethanol concentration-time curve (AUC) was lower during P1 (215.33 mg.h dl(-1)) than during P2 (231.33 mg.h dl(-1))(P = 0.8253). No significant differences were found on ethanol pharmacokinetics in either phase of the menstrual cycle.

  17. Effects of pathological conditions on ocular pharmacokinetics of antimicrobial drugs.

    Science.gov (United States)

    Ueda, Kayoko; Ohtori, Akira; Tojo, Kakuji

    2010-10-01

    A diffusion model of ocular pharmacokinetics was used to estimate the effects of pathological conditions on ocular pharmacokinetics. In vivo rabbit data after topical instillation of ciprofloxacin and ofloxacin were compared with the simulated concentrations in the aqueous and vitreous humors. The barrier capacity of the surrounding membranes such as the retina/choroid/sclera (RCS) membrane and the cornea was characterized by dimensionless Sherwood number derived by the pseudo-steady state approach (PSSA). We assumed the barrier capacity decreased by inflammation; when the barrier capacity of the RCS membrane and the cornea was assumed to be one-tenth for the RCS membrane and a half for the cornea respectively, the in vivo data agreed with the simulated profile without contradiction. The drug concentration gradient simulated in the vitreous body near the RCS membrane was more significant in the inflamed eyes than in the normal eyes, suggesting that the elimination of the drugs from the RCS membrane was enhanced by inflammation. The present diffusion model can better describe the ocular pharmacokinetics in both normal and diseased conditions.

  18. Transplacental pharmacokinetics of diclofenac in perfused human placenta.

    Science.gov (United States)

    Shintaku, Kyohei; Hori, Satoko; Tsujimoto, Masayuki; Nagata, Hideaki; Satoh, Shoji; Tsukimori, Kiyomi; Nakano, Hitoo; Fujii, Tomoyuki; Taketani, Yuji; Ohtani, Hisakazu; Sawada, Yasufumi

    2009-05-01

    The aims of this study were to evaluate the transplacental transfer properties of diclofenac and to determine the effect of L-lactic acid on the transplacental transfer of diclofenac. The maternal and fetal vessels of human placenta were perfused in a single-pass mode with a solution containing diclofenac and antipyrine. The transplacental pharmacokinetic model was fitted to the time profiles of the drug concentrations in the effluent and placenta to obtain transplacental pharmacokinetic parameters. In addition, chloride ion in the perfusate was partially replaced with L-lactic acid to see the change in the transplacental transfer properties of diclofenac. The TPT(ss) value (ratio of the rate of amount transferred across the placenta to that infused in the steady state) of diclofenac was 2.22%, which was approximately one-third that of antipyrine and was significantly reduced in the presence of L-lactic acid. The transplacental pharmacokinetic model could adequately explain the transplacental transfer of diclofenac with influx clearances from maternal and fetal perfusates to placental tissue of 0.276 and 0.0345 ml/min/g cotyledon and efflux rate constants from placental tissue to maternal and fetal perfusates of 0.406 and 0.0337 min(-1), respectively. By taking into account protein binding, the placental tissue/plasma concentration ratio in humans for diclofenac was estimated to be 0.108 ml/g of cotyledon and was smaller than that of antipyrine. In conclusion, human placental perfusion and transplacental pharmacokinetic modeling allowed us to determine the transplacental transfer properties of diclofenac quantitatively. Diclofenac may share transplacental transfer system(s) with L-lactic acid.

  19. Bioavailability and Pharmacokinetics of Oral Cocaine in Humans.

    Science.gov (United States)

    Coe, Marion A; Jufer Phipps, Rebecca A; Cone, Edward J; Walsh, Sharon L

    2018-06-01

    The pharmacokinetic profile of oral cocaine has not been fully characterized and prospective data on oral bioavailability are limited. A within-subject study was performed to characterize the bioavailability and pharmacokinetics of oral cocaine. Fourteen healthy inpatient participants (six males) with current histories of cocaine use were administered two oral doses (100 and 200 mg) and one intravenous (IV) dose (40 mg) of cocaine during three separate dosing sessions. Plasma samples were collected for up to 24 h after dosing and analyzed for cocaine and metabolites by gas chromatography-mass spectrometry. Pharmacokinetic parameters were calculated by non-compartmental analysis, and a two-factor model was used to assess for dose and sex differences. The mean ± SEM oral cocaine bioavailability was 0.32 ± 0.04 after 100 and 0.45 ± 0.06 after 200 mg oral cocaine. Volume of distribution (Vd) and clearance (CL) were both greatest after 100 mg oral (Vd = 4.2 L/kg; CL = 116.2 mL/[min kg]) compared to 200 mg oral (Vd = 2.9 L/kg; CL = 87.5 mL/[min kg]) and 40 mg IV (Vd = 1.3 L/kg; CL = 32.7 mL/[min kg]). Oral cocaine area-under-thecurve (AUC) and peak concentration increased in a dose-related manner. AUC metabolite-to-parent ratios of benzoylecgonine and ecgonine methyl ester were significantly higher after oral compared to IV administration and highest after the lower oral dose. In addition, minor metabolites were detected in higher concentrations after oral compared to IV cocaine. Oral cocaine produced a pharmacokinetic profile different from IV cocaine, which appears as a rightward and downward shift in the concentration-time profile. Cocaine bioavailability values were similar to previous estimates. Oral cocaine also produced a unique metabolic profile, with greater concentrations of major and minor metabolites.

  20. Pharmacokinetic Comparative Study of Gastrodin and Rhynchophylline after Oral Administration of Different Prescriptions of Yizhi Tablets in Rats by an HPLC-ESI/MS Method

    Science.gov (United States)

    Ge, Zhaohui; Liang, Qionglin; Wang, Yiming; Luo, Guoan

    2014-01-01

    Pharmacokinetic characters of rhynchophylline (RIN), gastrodin (GAS), and gastrodigenin (p-hydroxybenzyl alcohol, HBA) were investigated after oral administration of different prescriptions of Yizhi: Yizhi tablets or effective parts of tianma (total saponins from Gastrodiae, EPT) and gouteng (rhynchophylla alkaloids, EPG). At different predetermined time points after administration, the concentrations of GAS, HBA, and RIN in rat plasma were determined by an HPLC-ESI/MS method, and the main pharmacokinetic parameters were investigated. The results showed that the pharmacokinetic parameters C max and AUC0–∞ (P < 0.05) were dramatically different after oral administration of different prescriptions of Yizhi. The data indicated that the pharmacokinetic processes of GAS, HBA, and RIN in rats would interact with each other or be affected by other components in Yizhi. The rationality of the compatibility of Uncaria and Gastrodia elata as a classic “herb pair” has been verified from the pharmacokinetic viewpoint. PMID:25610474

  1. Pharmacokinetic Comparative Study of Gastrodin and Rhynchophylline after Oral Administration of Different Prescriptions of Yizhi Tablets in Rats by an HPLC-ESI/MS Method

    Directory of Open Access Journals (Sweden)

    Zhaohui Ge

    2014-01-01

    Full Text Available Pharmacokinetic characters of rhynchophylline (RIN, gastrodin (GAS, and gastrodigenin (p-hydroxybenzyl alcohol, HBA were investigated after oral administration of different prescriptions of Yizhi: Yizhi tablets or effective parts of tianma (total saponins from Gastrodiae, EPT and gouteng (rhynchophylla alkaloids, EPG. At different predetermined time points after administration, the concentrations of GAS, HBA, and RIN in rat plasma were determined by an HPLC-ESI/MS method, and the main pharmacokinetic parameters were investigated. The results showed that the pharmacokinetic parameters Cmax and Cmax⁡ and AUC0–∞ (P<0.05 were dramatically different after oral administration of different prescriptions of Yizhi. The data indicated that the pharmacokinetic processes of GAS, HBA, and RIN in rats would interact with each other or be affected by other components in Yizhi. The rationality of the compatibility of Uncaria and Gastrodia elata as a classic “herb pair” has been verified from the pharmacokinetic viewpoint.

  2. Interactions between recreational drugs and antiretroviral agents.

    Science.gov (United States)

    Antoniou, Tony; Tseng, Alice Lin-In

    2002-10-01

    To summarize existing data regarding potential interactions between recreational drugs and drugs commonly used in the management of HIV-positive patients. Information was obtained via a MEDLINE search (1966-August 2002) using the MeSH headings human immunodeficiency virus, drug interactions, cytochrome P450, medication names commonly prescribed for the management of HIV and related opportunistic infections, and names of commonly used recreational drugs. Abstracts of national and international conferences, review articles, textbooks, and references of all articles were also reviewed. Literature on pharmacokinetic interactions was considered for inclusion. Pertinent information was selected and summarized for discussion. In the absence of specific data, prediction of potential clinically significant interactions was based on pharmacokinetic and pharmacodynamic properties. All protease inhibitors (PIs) and nonnucleoside reverse transcriptase inhibitors are substrates and potent inhibitors or inducers of the cytochrome P450 system. Many classes of recreational drugs, including benzodiazepines, amphetamines, and opioids, are also metabolized by the liver and can potentially interact with antiretrovirals. Controlled interaction studies are often not available, but clinically significant interactions have been observed in a number of case reports. Overdoses secondary to interactions between the "rave" drugs methylenedioxymethamphetamine (MDMA) or gamma-hydroxybutyrate (GHB) and PIs have been reported. PIs, particularly ritonavir, may also inhibit metabolism of amphetamines, ketamine, lysergic acid diethylmide (LSD), and phencyclidine (PCP). Case series and pharmacokinetic studies suggest that nevirapine and efavirenz induce methadone metabolism, which may lead to symptoms of opiate withdrawal. A similar interaction may exist between methadone and the PIs ritonavir and nelfinavir, although the data are less consistent. Opiate metabolism can be inhibited or induced by

  3. How do patients actually experience and use art in hospitals? The significance of interaction: a user-oriented experimental case study.

    Science.gov (United States)

    Nielsen, Stine L; Fich, Lars B; Roessler, Kirsten K; Mullins, Michael F

    2017-12-01

    This article aims to understand patient wellbeing and satisfaction and to qualify the current guidelines for the application of art in hospitals. Employing anthropological methods, we focus on the interactional aspects of art in health interventions. A user-oriented study ranked 20 paintings, followed by an experiment using paintings in the dayroom of five medical wards. Fieldwork was done over a two-week period. During the first week, dayrooms were configured without the presence of art and in the second week were configured with the artworks. Semi-structured interviews, observation, participant observation and informal conversation were carried out and were informed by thermal cameras, which monitored the usage, patient occupation and flow in two of the dayrooms. The study shows that art contributes to creating an environment and atmosphere where patients can feel safe, socialize, maintain a connection to the world outside the hospital and support their identity. We conclude that the presence of visual art in hospitals contributes to health outcomes by improving patient satisfaction as an extended form of health care. The article draws attention to further research perspectives and methods associated with the development of art in hospitals.

  4. Pharmacokinetics of Botanical Drugs and Plant Extracts.

    Science.gov (United States)

    Dominguez More, Gina Paola; Cardenas, Paola Andrea; Costa, Geison M; Simoes, Claudia M O; Aragon, Diana Marcela

    2017-01-01

    Botanical drugs contain plant extracts, which are complex mixtures of compounds. As with conventional drugs, it is necessary to validate their efficacy and safety through preclinical and clinical studies. However, pharmacokinetic studies for active constituents or characteristic markers in botanical drugs are rare. The objective of this review was to investigate the global state of the art in pharmacokinetic studies of active ingredients present in plant extracts and botanical drugs. A review of pharmacokinetics studies of chemical constituents of plant extracts and botanical drugs was performed, with a total of 135 studies published between January 2004 and February 2015 available in recognized scientific databases. Botanical preparations were mainly found in the form of aqueous extracts of roots and rhizomes. The most widely studied species was Salvia miltiorrhiza Bunge, and the compound most frequently used as a pharmacokinetic marker was berberine. Most studies were performed using the Sprague Dawley rat model, and the preparations were mainly administered orally in a single dose. Quantification of plasma concentrations of pharmacokinetic markers was performed mainly by liquid-liquid extraction, followed by high performance liquid chromatography coupled to mass spectrometry detector. In conclusion, in recent years there has been an increasing interest among researchers worldwide in the study of pharmacokinetics of bioactive compounds in botanical drugs and plant extracts, especially those from the Traditional Chinese Medicine. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  5. Effect of antibodies to calcitonin on the pharmacokinetics and the pharmacodynamics of the hormone.

    Science.gov (United States)

    Tagliaro, F; Dorizzi, R; Luisetto, G

    1995-01-01

    Calcitonin pharmacokinetics and pharmacodynamics were studied in two groups of patients with postmenopausal osteoporosis, who, treated for one year with intranasal Asu1.7-eel calcitonin (eCT), had (Ab+) and had not (Ab-) developed a specific immune response to the drug. The treatment consisted of daily intranasal administrations of eCT (80 IU/die) with 1 g supplemental calcium. Eight women who had developed specific antibodies and 5 who had not, were given 50 IU of CT i.m., in order to assess the pharmacokinetics and pharmacodynamics of the drug. The rise of serum levels of the hormone was significantly greater in Ab+ than in Ab- patients. At the end of the study, no significant differences in mineral bone loss between the two groups were found. In conclusion, the presence of antibodies to eCT does not represent a negative event in the therapy of osteoporosis, but significantly affects the pharmacokinetics of the drug.

  6. Effect modification of air pollution on Urinary 8-Hydroxy-2'-Deoxyguanosine by genotypes: an application of the multiple testing procedure to identify significant SNP interactions

    Directory of Open Access Journals (Sweden)

    Christiani David C

    2010-12-01

    Full Text Available Abstract Background Air pollution is associated with adverse human health, but mechanisms through which pollution exerts effects remain to be clarified. One suggested pathway is that pollution causes oxidative stress. If so, oxidative stress-related genotypes may modify the oxidative response defenses to pollution exposure. Methods We explored the potential pathway by examining whether an array of oxidative stress-related genes (twenty single nucleotide polymorphisms, SNPs in nine genes modified associations of pollutants (organic carbon (OC, ozone and sulfate with urinary 8-hydroxy-2-deoxygunosine (8-OHdG, a biomarker of oxidative stress among the 320 aging men. We used a Multiple Testing Procedure in R modified by our team to identify the significance of the candidate genes adjusting for a priori covariates. Results We found that glutathione S-tranferase P1 (GSTP1, rs1799811, M1 and catalase (rs2284367 and group-specific component (GC, rs2282679, rs1155563 significantly or marginally significantly modified effects of OC and/or sulfate with larger effects among those carrying the wild type of GSTP1, catalase, non-wild type of GC and the non-null of GSTM1. Conclusions Polymorphisms of oxidative stress-related genes modified effects of OC and/or sulfate on 8-OHdG, suggesting that effects of OC or sulfate on 8-OHdG and other endpoints may be through the oxidative stress pathway.

  7. Isoform-specific interactions between meprin metalloproteases and the catalytic subunit of protein kinase A: significance in acute and chronic kidney injury

    Science.gov (United States)

    Niyitegeka, Jean-Marie V.; Bastidas, Adam C.; Newman, Robert H.; Taylor, Susan S.

    2014-01-01

    Meprin metalloproteases are abundantly expressed in the brush-border membranes of kidney proximal tubules. Meprins are implicated in ischemia-reperfusion (IR)-induced renal injury and diabetic nephropathy. The protein kinase A (PKA) signaling pathway modulates extracellular matrix metabolism in diabetic kidneys. The present study evaluated isoform-specific interactions between the catalytic subunit of PKA (PKA C) and meprins. To this end, cytosolic-enriched kidney proteins from meprin αβ double knockout mice, and purified forms of recombinant mouse PKA Cα, Cβ1, and Cβ2, were incubated with activated forms of either homomeric meprin A or meprin B. The cleaved protein products were subjected to SDS-PAGE and analyzed by Coomassie staining and Western blot analysis. While meprin A only cleaved PKA Cβ1, meprin B cleaved all three PKA C isoforms. Analysis of the proteolytic fragments by mass spectrometry revealed that meprin A and B cleave the PKA C isoforms at defined sites, resulting in unique cleavage products. Michaelis-Menten enzyme kinetics demonstrated that meprin B-mediated cleavage of PKA Cα occurs at a rate consistent with that of other physiologically relevant meprin substrates. Meprin cleavage decreased the kinase activity of PKA Cα, Cβ1, and Cβ2. PKA C levels were higher in diabetic kidneys, with evidence of in vivo fragmentation in wild-type diabetic kidneys. Confocal microscopy showed localization of meprin A in the glomeruli of diabetic kidneys. At 3 h post-IR, PKA C levels in proximal tubules decreased compared with distal tubules, which lack meprins. These data suggest that meprins may impact kidney injury, in part, via modulation of PKA signaling pathways. PMID:25354939

  8. Mineral Dissolution and Precipitation due to Carbon Dioxide-Water-Rock Interactions: The Significance of Accessory Minerals in Carbonate Reservoirs (Invited)

    Science.gov (United States)

    Kaszuba, J. P.; Marcon, V.; Chopping, C.

    2013-12-01

    Accessory minerals in carbonate reservoirs, and in the caprocks that seal these reservoirs, can provide insight into multiphase fluid (CO2 + H2O)-rock interactions and the behavior of CO2 that resides in these water-rock systems. Our program integrates field data, hydrothermal experiments, and geochemical modeling to evaluate CO2-water-rock reactions and processes in a variety of carbonate reservoirs in the Rocky Mountain region of the US. These studies provide insights into a wide range of geologic environments, including natural CO2 reservoirs, geologic carbon sequestration, engineered geothermal systems, enhanced oil and gas recovery, and unconventional hydrocarbon resources. One suite of experiments evaluates the Madison Limestone on the Moxa Arch, Southwest Wyoming, a sulfur-rich natural CO2 reservoir. Mineral textures and geochemical features developed in the experiments suggest that carbonate minerals which constitute the natural reservoir will initially dissolve in response to emplacement of CO2. Euhedral, bladed anhydrite concomitantly precipitates in response to injected CO2. Analogous anhydrite is observed in drill core, suggesting that secondary anhydrite in the natural reservoir may be related to emplacement of CO2 into the Madison Limestone. Carbonate minerals ultimately re-precipitate, and anhydrite dissolves, as the rock buffers the acidity and reasserts geochemical control. Another suite of experiments emulates injection of CO2 for enhanced oil recovery in the Desert Creek Limestone (Paradox Formation), Paradox Basin, Southeast Utah. Euhedral iron oxyhydroxides (hematite) precipitate at pH 4.5 to 5 and low Eh (approximately -0.1 V) as a consequence of water-rock reaction. Injection of CO2 decreases pH to approximately 3.5 and increases Eh by approximately 0.1 V, yielding secondary mineralization of euhedral pyrite instead of iron oxyhydroxides. Carbonate minerals also dissolve and ultimately re-precipitate, as determined by experiments in the

  9. Does a kampo medicine containing schisandra fruit affect pharmacokinetics of nifedipine like grapefruit juice?

    Science.gov (United States)

    Makino, Toshiaki; Mizuno, Fumika; Mizukami, Hajime

    2006-10-01

    Herb-drug interaction has attracted attention as medicinal topics recently. However, the drug information is sometimes confusing. Previous in vitro studies revealed that schisandra fruit had strong inhibitory effect on CYP3A4 and claimed the possibilities of its herb-drug interaction. In the present study, we evaluated the inhibitory effects of schisandra fruit and shoseiryuto, an herbal formula in Japanese traditional kampo medicine containing eight herbal medicines including schisandra fruit, on rat CYP3A activity in vitro, and the effect of shoseiryuto on pharmacokinetics of nifedipine in rats, in comparison with those of grapefruit juice, a well-characterized natural CYP3A inhibitor. Shoseiryuto and its herbal constituents, schisandra fruit, ephedra herb and cinnamon bark exhibited in vitro inhibitory effect of CYP3A. Although shoseiryuto inhibited rat CYP3A activity in vitro with a degree comparable to grapefruit juice, shoseiryuto did not significantly affect a plasma concentration profile of nifedipine in rats as grapefruit juice did. These results indicate that in vivo experiments using the extract of herbal medicine prepared with the same dosage form as patients take are necessary to provide proper information about herb-drug interaction.

  10. A drug-drug interaction study to assess the effect of the CYP1A2 inhibitor fluvoxamine on the pharmacokinetics of dovitinib (TKI258) in patients with advanced solid tumors

    NARCIS (Netherlands)

    de Weger, Vincent A; Goel, Sanjay; von Moos, Roger; Schellens, Jan H M; Mach, Nicholas; Tan, Eugene; Anand, Suraj; Scott, Jeffrey W; Lassen, Ulrik N

    PURPOSE: Dovitinib is an orally available multi tyrosine kinase inhibitor which inhibits VEGFR 1-3, FGFR 1-3, and PDGFR. This study was performed to investigate the potential drug-drug interaction of dovitinib with the CYP1A2 inhibitor fluvoxamine in patients with advanced solid tumors. METHODS:

  11. A drug-drug interaction study to assess the effect of the CYP1A2 inhibitor fluvoxamine on the pharmacokinetics of dovitinib (TKI258) in patients with advanced solid tumors

    DEFF Research Database (Denmark)

    de Weger, Vincent A; Goel, Sanjay; von Moos, Roger

    2018-01-01

    PURPOSE: Dovitinib is an orally available multi tyrosine kinase inhibitor which inhibits VEGFR 1-3, FGFR 1-3, and PDGFR. This study was performed to investigate the potential drug-drug interaction of dovitinib with the CYP1A2 inhibitor fluvoxamine in patients with advanced solid tumors. METHODS: ...

  12. Pharmacokinetics of repeated oral doses of amlodipine and amlodipine plus telmisartan in healthy volunteers.

    Science.gov (United States)

    Stangier, J; Su, C A

    2000-12-01

    This open-label, crossover study was performed to establish if there is evidence for interaction between telmisartan, an angiotensin II antagonist, and amlodipine, a class II (dihydropyridine) calcium channel antagonist, on the basis of pharmacokinetics and safety. In a two-way crossover trial, 12 healthy Caucasian males were randomized to receive once daily for 9 days oral amlodipine 10 mg with or without oral telmisartan 120 mg. After a washout period of > or = 13 days, the subjects were switched to the other medication regimen. The geometric means of the primary pharmacokinetic parameters at steady state (day 9) for amlodipine when given alone were the following: maximum plasma concentration (Cmax) 17.7 ng/mL, area under the plasma concentration-time curve (AUC) 331 ng.h/mL, and renal clearance 39.5 mL/min, with 8% of the total amlodipine dose being excreted. When concomitant telmisartan was given, the respective values were 18.7 ng/mL, 352 ng.h/mL, and 43.0 mL/min, with 9.4% of the total amlodipine dose being excreted renally. The limits of the 90% confidence intervals (CIs) for the ratios of these steady-state parameters were 0.97 to 1.14 for Cmax and 0.98 to 1.16 for AUC; both were within the predefined reference range (0.8 to 1.25) for bioequivalence. The high intersubject variability in urinary amlodipine excretion resulted in bioequivalence not being demonstrated for renal clearance. Adverse effects were few, mild to moderate in intensity, and transient whether amlodipine was given alone or with telmisartan. Vital signs, except for blood pressure, and clinical laboratory values were unaffected by either medication. The findings of this study show that concomitant telmisartan and amlodipine may be administered as there is no clinically significant variation in primary pharmacokinetic parameters of amlodipine in the presence of telmisartan, and the safety of the combination is comparable to that of amlodipine alone.

  13. Modeling, Analysis, and Control of a Hypersonic Vehicle with Significant Aero-Thermo-Elastic-Propulsion Interactions: Elastic, Thermal and Mass Uncertainty

    Science.gov (United States)

    Khatri, Jaidev

    This thesis examines themodeling, analysis, and control system design issues for scramjet powered hypersonic vehicles. A nonlinear three degrees of freedom longitudinal model which includes aero-propulsion-elasticity effects was used for all analyses. This model is based upon classical compressible flow and Euler-Bernouli structural concepts. Higher fidelity computational fluid dynamics and finite element methods are needed for more precise intermediate and final evaluations. The methods presented within this thesis were shown to be useful for guiding initial control relevant design. The model was used to examine the vehicle's static and dynamic characteristics over the vehicle's trimmable region. The vehicle has significant longitudinal coupling between the fuel equivalency ratio (FER) and the flight path angle (FPA). For control system design, a two-input two-output plant (FER - elevator to speed-FPA) with 11 states (including 3 flexible modes) was used. Velocity, FPA, and pitch were assumed to be available for feedback. Aerodynamic heat modeling and design for the assumed TPS was incorporated to original Bolender's model to study the change in static and dynamic properties. De-centralized control stability, feasibility and limitations issues were dealt with the change in TPS elasticity, mass and physical dimension. The impact of elasticity due to TPS mass, TPS physical dimension as well as prolonged heating was also analyzed to understand performance limitations of de-centralized control designed for nominal model.

  14. Population pharmacokinetics of exendin-(9-39) and clinical dose selection in patients with congenital hyperinsulinism.

    Science.gov (United States)

    Ng, Chee M; Tang, Fei; Seeholzer, Steven H; Zou, Yixuan; De León, Diva D

    2018-03-01

    Congenital hyperinsulinism (HI) is the most common cause of persistent hypoglycaemia in infants and children. Exendin-(9-39), an inverse glucagon-like peptide 1 (GLP-1) agonist, is a novel therapeutic agent for HI that has demonstrated glucose-raising effect. We report the first population pharmacokinetic (PopPK) model of the exendin-(9-39) in patients with HI and propose the optimal dosing regimen for future clinical trials in neonates with HI. A total of 182 pharmacokinetic (PK) observations from 26 subjects in three clinical studies were included for constructing the PopPK model using first order conditional estimation (FOCE) with interaction method in nonlinear mixed-effects modelling (NONMEM). Exposure metrics (area under the curve [AUC] and maximum plasma concentration [C max ]) at no observed adverse effect levels (NOAELs) in rats and dogs were determined in toxicology studies. Observed concentration-time profiles of exendin-(9-39) were described by a linear two-compartmental PK model. Following allometric scaling of PK parameters, age and creatinine clearance did not significantly affect clearance. The calculated clearance and elimination half-life for adult subjects with median weight of 69 kg were 11.8 l h -1 and 1.81 h, respectively. The maximum recommended starting dose determined from modelling and simulation based on the AUC 0-last at the NOAEL and predicted AUC 0-inf using the PopPK model was 27 mg kg -1  day -1 intravenously. This is the first study to investigate the PopPK of exendin-(9-39) in humans. The final PopPK model was successfully used with preclinical toxicology findings to propose the optimal dosing regimen of exendin-(9-39) for clinical studies in neonates with HI, allowing for a more targeted dosing approach to achieve desired glycaemic response. © 2017 The British Pharmacological Society.

  15. Gentamicin pharmacokinetics in the chicken inner ear.

    Science.gov (United States)

    Bunting, Eric C; Park, Debra L; Durham, Dianne; Girod, Douglas A

    2004-06-01

    Avians have the unique ability to regenerate cochlear hair cells that are lost due to ototoxins or excessive noise. Many methodological techniques are available to damage the hair cells for subsequent scientific study. A recent method utilizes topical application of an ototoxic drug to the round window membrane. The current study examines the pharmacokinetics of gentamicin in the inner ear of chickens following topical application to the round window membrane or a single systemic high dose given intraperitoneally. Chickens were given gentamicin topically or systemically and survived for 1, 4, 12, 24, or 120 h (controls at 4 and 120 h). Serum and perilymph samples were obtained prior to sacrifice and measured for gentamicin levels. Results revealed higher levels of gentamicin in the perilymph of topically treated chickens than systemically treated chickens, with significant amounts of gentamicin still present in both at the latest survival time of 5 days. As expected, systemically treated chickens had much higher levels of gentamicin in the serum than topically treated chickens. Advantages and disadvantages to each method of drug administration are discussed.

  16. Virtual pharmacokinetic model of human eye.

    Science.gov (United States)

    Kotha, Sreevani; Murtomäki, Lasse

    2014-07-01

    A virtual pharmacokinetic 3D model of the human eye is built using Comsol Multiphysics® software, which is based on the Finite Element Method (FEM). The model considers drug release from a polymer patch placed on sclera. The model concentrates on the posterior part of the eye, retina being the target tissue, and comprises the choroidal blood flow, partitioning of the drug between different tissues and active transport at the retina pigment epithelium (RPE)-choroid boundary. Although most straightforward, in order to check the mass balance, no protein binding or metabolism is yet included. It appeared that the most important issue in obtaining reliable simulation results is the finite element mesh, while time stepping has hardly any significance. Simulations were extended to 100,000 s. The concentration of a drug is shown as a function of time at various points of retina, as well as its average value, varying several parameters in the model. This work demonstrates how anybody with basic knowledge of calculus is able to build physically meaningful models of quite complex biological systems. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Pharmacokinetic Study of Piracetam in Focal Cerebral Ischemic Rats.

    Science.gov (United States)

    Paliwal, Pankaj; Dash, Debabrata; Krishnamurthy, Sairam

    2018-04-01

    Cerebral ischemia affects hepatic enzymes and brain permeability extensively. Piracetam was investigated up to phase III of clinical trials and there is lack of data on brain penetration in cerebral ischemic condition. Thus, knowledge of the pharmacokinetics and brain penetration of piracetam during ischemic condition would aid to improve pharmacotherapeutics in ischemic stroke. Focal cerebral ischemia was induced by middle cerebral artery occlusion for 2 h in male Wistar rats followed by reperfusion. After 24 h of middle cerebral artery occlusion or 22 h of reperfusion, piracetam was administered for pharmacokinetic, brain penetration, and pharmacological experiments. In pharmacokinetic study, blood samples were collected at different time points after 200-mg/kg (oral) and 75-mg/kg (intravenous) administration of piracetam through right external jugular vein cannulation. In brain penetration study, the cerebrospinal fluid, systemic blood, portal blood, and brain samples were collected at pre-designated time points after 200-mg/kg oral administration of piracetam. In a separate experiment, the pharmacological effect of the single oral dose of piracetam in middle cerebral artery occlusion was assessed at a dose of 200 mg/kg. All the pharmacokinetic parameters of piracetam including area under curve (AUC 0-24 ), maximum plasma concentration (C max ), time to reach the maximum plasma concentration (t max ), elimination half-life (t 1/2 ), volume of distribution (V z ), total body clearance, mean residence time, and bioavailability were found to be similar in ischemic stroke condition except for brain penetration. Piracetam exposure (AUC 0-2 ) in brain and CSF were found to be 2.4- and 3.1-fold higher, respectively, in ischemic stroke compared to control rats. Piracetam significantly reduced infarct volume by 35.77% caused by middle cerebral artery occlusion. There was no change in the pharmacokinetic parameters of piracetam in the ischemic stroke model except for

  18. Effect of feeding on the pharmacokinetics of oral minocycline in healthy research dogs.

    Science.gov (United States)

    Hnot, Melanie L; Cole, Lynette K; Lorch, Gwendolen; Rajala-Schultz, Paivi J; Papich, Mark G

    2015-12-01

    The effect of food on minocycline oral absorption in dogs is unknown. The objective was to determine the pharmacokinetics of minocycline after administration of a single oral dose in fed and fasted dogs. Ten research hounds were administered oral minocycline (approximately 5 mg/kg) with and without food, in a crossover study, with a one-week wash-out between treatments. Blood samples were collected immediately prior to minocycline administration and over 24 h. Minocycline plasma drug concentrations were measured using high-performance liquid chromatography using ultraviolet detection and were analysed with compartmental modelling to determine primary pharmacokinetic parameters. Each dog was analysed independently, followed by calculation of means and variation of the dogs. The Wilcoxon signed-rank test [analysing secondary pharmacokinetic parameters - peak concentration (CMAX ), area under the concentration versus time curve (AUC)] was used to compare the two groups. A population pharmacokinetic modelling approach was performed using nonlinear mixed effects modelling of primary parameters for the population as fixed effects and the difference between subjects as a random effect. Covariate analysis was used to identify the source of variability in the population. No significant difference was found between treatments for AUC (P = 0.0645), although AUC was higher in fasted dogs. A significant difference was found for CMAX (P = 0.0059), with fasted dogs attaining a higher CMAX . The covariate of fed versus fasted accounted for a significant variation in the pharmacokinetics. Because feeding was a significant source of variation for the population's primary pharmacokinetic parameters and fasted dogs had higher minocycline concentrations, we recommend administering minocycline without food. © 2015 ESVD and ACVD.

  19. ADAM, a hands-on patient simulator for teaching principles of drug disposition and compartmental pharmacokinetics.

    Science.gov (United States)

    Zuna, Ines; Holt, Andrew

    2017-11-01

    To design, construct and validate a pharmacokinetics simulator that offers students hands-on opportunities to participate in the design, administration and analysis of oral and intravenous dosing regimens. The Alberta Drug Administration Modeller (ADAM) is a mechanical patient in which peristaltic circulation of water through a network of silicone tubing and glass bottles creates a representation of the outcomes of drug absorption, distribution, metabolism and elimination. Changing peristaltic pump rates and volumes in bottles allows values for pharmacokinetic constants to be varied, thereby simulating differences in drug properties and in patient physiologies and pathologies. Following administration of methylene blue dye by oral or intravenous routes, plasma and/or urine samples are collected and drug concentrations are determined spectrophotometrically. The effectiveness of the simulator in enhancing student competence and confidence was assessed in two undergraduate laboratory classes. The simulator effectively models one- and two-compartment drug behaviour in a mathematically-robust and realistic manner. Data allow calculation of numerous pharmacokinetic constants, by traditional graphing methods or with curve-fitting software. Students' competence in solving pharmacokinetic problems involving calculations and graphing improved significantly, while an increase in confidence and understanding was reported. The ADAM is relatively inexpensive and straightforward to construct, and offers a realistic, hands-on pharmacokinetics learning opportunity for students that effectively complements didactic lectures. © 2017 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.

  20. Population pharmacokinetics of tamsulosin hydrochloride in paediatric patients with neuropathic and non-neuropathic bladder

    Science.gov (United States)

    Tsuda, Yasuhiro; Tatami, Shinji; Yamamura, Norio; Tadayasu, Yusuke; Sarashina, Akiko; Liesenfeld, Karl-Heinz; Staab, Alexander; Schäfer, Hans-Günter; Ieiri, Ichiro; Higuchi, Shun

    2010-01-01

    AIMS The main objective of this study was to characterize the population pharmacokinetics of tamsulosin hydrochloride (HCl) in paediatric patients with neuropathic and non-neuropathic bladder. A secondary objective was to compare the pharmacokinetics in paediatric patients and adults. METHODS Tamsulosin HCl plasma concentrations in 1082 plasma samples from 189 paediatric patients (age range 2–16 years) were analyzed with NONMEM, applying a one compartment model with first-order absorption. Based on the principles of allometry, body weight was incorporated in the base model, along with fixed allometric exponents. Covariate analysis was performed by means of a stepwise forward inclusion and backward elimination procedure. Simulations based on the final model were used to compare the pharmacokinetics with those in adults. RESULTS Beside the priori-implemented body weight, only α1-acid glycoprotein had an effect on both apparent clearance and apparent volume of distribution. No other investigated covariates, including gender, age, race, patient population and concomitant therapy with anti-cholinergics, significantly affected the pharmacokinetics of tamsulosin HCl (P tamsulosin HCl in paediatric patients was established and it described the data well. There was no major difference in the pharmacokinetics of tamsulosin HCl between paediatric patients (age range 2–16 years) and adults when the effect of body weight was taken into consideration. PMID:20642551

  1. Erythromycin potentiates PR interval prolonging effect of verapamil in the rat: A pharmacodynamic drug interaction

    International Nuclear Information System (INIS)

    Dakhel, Yaman; Jamali, Fakhreddin

    2006-01-01

    Calcium channel blockers and macrolide antibiotics account for many drug interactions. Anecdotal reports suggest interactions between the two resulting in severe side effects. We studied the interaction between verapamil and erythromycin in the rat to see whether it occurs at the pharmacokinetics or pharmacodynamic level. Adult male Sprague-Dawley rats received doses of 1 mg/kg verapamil or 100 mg/kg erythromycin alone or in combination (n = 6/group). Serial blood samples (0-6 h) were taken for determination of the drug concentrations using HPLC. Electrocardiograms were recorded (0-6 h) through subcutaneously inserted lead II. Binding of the drugs to plasma proteins was studied using spiked plasma. Verapamil prolonged PR but not QT interval. Erythromycin prolonged QT but not PR interval. The combination resulted in a significant increase in PR interval prolongation and AV node blocks but did not further prolong QT interval. Pharmacokinetics and protein binding of neither drug were altered by the other. Our rat data confirm the anecdotal human case reports that combination of erythromycin and verapamil can result in potentiation of the cardiovascular response. The interaction appears to be at the pharmacodynamic rather than pharmacokinetic level hence may be extrapolated to other calcium channel antagonists

  2. PHARMACOKINETIC VARIATIONS OF OFLOXACIN IN NORMAL AND FEBRILE RABBITS

    Directory of Open Access Journals (Sweden)

    M. AHMAD, H. RAZA, G. MURTAZA AND N. AKHTAR

    2008-12-01

    Full Text Available The influence of experimentally Escherichia coli-induced fever (EEIF on the pharmacokinetics of ofloxacin was evaluated. Ofloxacin was administered @ 20 mg.kg-1 body weight intravenously to a group of eight healthy rabbits and compared these results to values in same eight rabbits with EEIF. Pharmacokinetic parameters of ofloxacin in normal and febrile rabbits were determined by using two compartment open kinetic model. Peak plasma level (Cmax and area under the plasma concentration-time curve (AUC0-α in normal and febrile rabbits did not differ (P>0.05. However, area under first moment of plasma concentration-time curve (AUMC0-α in febrile rabbits was significantly (P<0.05 higher than that in normal rabbits. Mean values for elimination rate constant (Ke, elimination half life (t1/2β and apparent volume of distribution (Vd were significantly (P<0.05 lower in febrile rabbits compared to normal rabbits, while mean residence time (MRT and total body clearance (Cl of ofloxacin did not show any significant difference in the normal and febrile rabbits. Clinical significance of the above results can be related to the changes in the volume of distribution and elimination half life that illustrates an altered steady state in febrile condition; hence, the need for an adjustment of dosage regimen in EEIF is required.

  3. Clinical pharmacokinetics of 5-methyltetrahydrohomofolate

    International Nuclear Information System (INIS)

    Loo, T.L.; Jiushi, L.; Lu, K.; Savaraj, N.

    1983-01-01

    DL-N5-Methyltetrahydrohomofolate (MTHHF; NSC-139490; N- [(4-[(2-(2-amino-3,4,5,6,7,8-hexahydro-4-oxo-5-methyl-6- pteridinyl)ethyl) amino) benzoyl)] -L-glutamate), a new folate antagonist of relatively low toxicity, is active against experimental tumor systems resistant to methotrexate and consequently now in clinical trial. We investigated its clinical pharmacokinetics in six patients; four of them received by rapid i.v. infusion tracer doses of [N5-methyl- 14 C]MTHHF ranging from 13 to 16 mg/sq m, and 2 received 150 mg/sq m; the total radioactivity dose was 100 to 200 mu Ci/patient. MTHHF was assayed by radiochemical and chromatographic techniques. The elimination of MTHHF from the plasma followed a triexponential pattern, with a harmonic mean initial half-life of 20.1 min, an intermediary half-life of 4.5 hr, and a terminal half-life of 74.6 hr. The apparent volume of distribution was 1.6 liters/kg, suggesting rapid and extensive tissue binding. This, together with the low total clearance of 0.2 ml/kg/min, contributed to the long half-life of this agent. Although 68% of the administered dose was excreted in the urine on the first day, only an additional 1% was excreted on the ensuing 3 days. In the two patients who received the higher dose, very little MTHHF was found in the cerebrospinal fluid. In concentrations ranging from 25 to 500 micrograms/ml, the drug was about 50% bound to plasma protein. MTHHF was not metabolized in humans as also reported in animals. These results suggest that MTHHF is excreted in the bile to certain extent. Moreover, since it tends to localize and persist in the body, to forestall cumulative toxicity, frequent administration of this agent should be undertaken only with caution

  4. Pharmacokinetics of Cefuroxime in Cortical and Cancellous Bone Obtained by Microdialysis - a Porcine Study

    DEFF Research Database (Denmark)

    Tøttrup, Mikkel; Forsingdal Hardlei, Tore; Bendtsen, Michael

    2014-01-01

    . As reference, free and total plasma concentrations were also measured. The animals received a bolus of 1500 mg cefuroxime over 30 min. No significant differences between key pharmacokinetic parameters for sealed and unsealed drill holes in cortical bone were found. The mean area under the concentration...... (MD) technique for measurement of cefuroxime in bone, and to obtain pharmacokinetic profiles for the same drug in porcine cortical and cancellous bone. Measurements were conducted in bone-wax sealed and unsealed drill holes in cortical bone, in drill holes in cancellous bone and in subcutaneous tissue...

  5. Individualized Hydrocodone Therapy Based on Phenotype, Pharmacogenetics, and Pharmacokinetic Dosing.

    Science.gov (United States)

    Linares, Oscar A; Fudin, Jeffrey; Daly, Annemarie L; Boston, Raymond C

    2015-12-01

    (1) To quantify hydrocodone (HC) and hydromorphone (HM) metabolite pharmacokinetics with pharmacogenetics in CYP2D6 ultra-rapid metabolizer (UM), extensive metabolizer (EM), and poor metabolizer (PM) metabolizer phenotypes. (2) To develop an HC phenotype-specific dosing strategy for HC that accounts for HM production using clinical pharmacokinetics integrated with pharmacogenetics for patient safety. In silico clinical trial simulation. Healthy white men and women without comorbidities or history of opioid, or any other drug or nutraceutical use, age 26.3±5.7 years (mean±SD; range, 19 to 36 y) and weight 71.9±16.8 kg (range, 50 to 108 kg). CYP2D6 phenotype-specific HC clinical pharmacokinetic parameter estimates and phenotype-specific percentages of HM formed from HC. PMs had lower indices of HC disposition compared with UMs and EMs. Clearance was reduced by nearly 60% and the t1/2 was increased by about 68% compared with EMs. The canonical order for HC clearance was UM>EM>PM. HC elimination mainly by the liver, represented by ke, was reduced about 70% in PM. However, HC's apparent Vd was not significantly different among UMs, EMs, and PM. The canonical order of predicted plasma HM concentrations was UM>EM>PM. For each of the CYP2D6 phenotypes, the mean predicted HM levels were within HM's therapeutic range, which indicates HC has significant phenotype-dependent pro-drug effects. Our results demonstrate that pharmacogenetics afford clinicians an opportunity to individualize HC dosing, while adding enhanced opportunity to account for its conversion to HM in the body.

  6. Different Influences on Tacrolimus Pharmacokinetics by Coadministrations of Zhi Ke and Zhi Shi in Rats

    Directory of Open Access Journals (Sweden)

    Shiuan-Pey Lin

    2011-01-01

    Full Text Available Tacrolimus, an immunosuppressant with narrow therapeutic window, has been used widely in transplant patients. Grapefruit juice and pomelo have been reported to increase the blood levels of tacrolimus. Zhi Ke and Zhi Shi, the ripe peels and unripe fruits of Citrus aurantium which is chemotaxonomically related to grapefruit and pomelo, are in wide use in clinical Chinese medicine. To investigate the possible interaction of these two Citrus herbs with tacrolimus, male Sprague-Dawley rats were orally given tacrolimus (1.5 mg/kg with and without Zhi Ke and Zhi Shi decoctions in a cross-over design. Blood samples were withdrawn via cardiopuncture at specific time and quantitated by a microparticle enzyme immunoassay. In addition, to explore the mechanism of interaction, LS 180 cell line was used for the transport study of rhodamine 123, a typical substrate of P-glycoprotein (P-gp. The results showed that Zhi Shi significantly decreased the Cmax⁡ and AUC0-t of tacrolimus by 72.4% and 72.0%, respectively, whereas Zhi Ke did not affect tacrolimus pharmacokinetics. LS 180 cell line study indicated that Zhi Shi increased the efflux activity of P-gp, enabling us to explain the decreased oral bioavailability of tacrolimus caused by Zhi Shi. Hence, we suggest that Zhi Shi be contraindicated for transplant patients treated with tacrolimus to reduce the risk of allograft rejection.

  7. Different Influences on Tacrolimus Pharmacokinetics by Coadministrations of Zhi Ke and Zhi Shi in Rats

    Science.gov (United States)

    Lin, Shiuan-Pey; Wu, Ping-Ping; Hou, Yu-Chi; Tsai, Shang-Yuan; Wang, Meng-Ju; Fang, Shih-Hua; Chao, Pei-Dawn Lee

    2011-01-01

    Tacrolimus, an immunosuppressant with narrow therapeutic window, has been used widely in transplant patients. Grapefruit juice and pomelo have been reported to increase the blood levels of tacrolimus. Zhi Ke and Zhi Shi, the ripe peels and unripe fruits of Citrus aurantium which is chemotaxonomically related to grapefruit and pomelo, are in wide use in clinical Chinese medicine. To investigate the possible interaction of these two Citrus herbs with tacrolimus, male Sprague-Dawley rats were orally given tacrolimus (1.5 mg/kg) with and without Zhi Ke and Zhi Shi decoctions in a cross-over design. Blood samples were withdrawn via cardiopuncture at specific time and quantitated by a microparticle enzyme immunoassay. In addition, to explore the mechanism of interaction, LS 180 cell line was used for the transport study of rhodamine 123, a typical substrate of P-glycoprotein (P-gp). The results showed that Zhi Shi significantly decreased the C max and AUC0−t of tacrolimus by 72.4% and 72.0%, respectively, whereas Zhi Ke did not affect tacrolimus pharmacokinetics. LS 180 cell line study indicated that Zhi Shi increased the efflux activity of P-gp, enabling us to explain the decreased oral bioavailability of tacrolimus caused by Zhi Shi. Hence, we suggest that Zhi Shi be contraindicated for transplant patients treated with tacrolimus to reduce the risk of allograft rejection. PMID:21318106

  8. Pharmacokinetics of thiamine derivatives especially of benfotiamine.

    Science.gov (United States)

    Loew, D

    1996-02-01

    Pharmacokinetic data of orally administered lipid-soluble thiamine analogues like benfotiamine are reviewed and assessed. It is quite clear that benfotiamine is absorbed much more better than water-soluble thiamine salts: maximum plasma levels of thiamine are about 5 times higher after benfotiamine, the bioavailability is at maximum about 3.6 times as high as that of thiamine hydrochloride and better than other lipophilic thiamine derivates. The physiological activity (alphaETK) increased only after benfotiamine was given. Due to its excellent pharmacokinetic profile benfotiamine should be preferred in treatment of relevant indications.

  9. Pharmacokinetic and pharmacogenomic profiles of telmisartan after the oral microdose and therapeutic dose.

    Science.gov (United States)

    Ieiri, Ichiro; Nishimura, Chisa; Maeda, Kazuya; Sasaki, Tomohiro; Kimura, Miyuki; Chiyoda, Takeshi; Hirota, Tekeshi; Irie, Shin; Shimizu, Hitoshi; Noguchi, Takanori; Yoshida, Kenji; Sugiyama, Yuichi

    2011-08-01

    In this study, we evaluated (a) the contribution of SLCO1B3 and UGT1A polymorphisms to the pharmacokinetics of telmisartan in two forms, a microdose (MD) and a therapeutic dose (TD); (b) linkage disequilibrium (LD) between UGT1A1 and UGT1A3; and (c) linearity in the pharmacokinetics of telmisartan between the two forms. Telmisartan was orally administered at MD condition (100 μg), and then at TD condition (80 mg) to 33 healthy volunteers whose genotypes were prescreened by DMET Plus. Plasma concentrations of telmisartan and its glucuronide were measured by LC-MS/MS, and population pharmacokinetic analysis was performed. No obvious effect of SLCO1B3 polymorphisms (334T>G, 699G>A, and rs11045585) on the pharmacokinetics of telmisartan was observed. The strong LD between UGT1A1*6 and UGT1A3*4a, and between UGT1A1*28 and UGT1A3*2a were observed. After both MD and TD administration, the mean area under the curve0-24 (±standard deviation) of telmisartan was significantly lower and higher in individuals with the UGT1A3*2a (TD, 1701±970 ng hr/ml; MD, 978±537 pg hr/ml) and *4a variants (TD, 5340±1168; MD, 3145±1093), respectively, compared with those in individuals with UGT1A3*1/*1 (TD, 2969±1456; MD, 1669±726). These results were quantitatively confirmed by population pharmacokinetic analysis. Nonlinearity of the dose-exposure relationship was observed between the MD and TD. The haplotypes of UGT1A3 significantly influenced pharmacokinetics of telmisartan and a strong LD between UGT1A1 genotype and UGT1A3 haplotype was observed. These findings are potentially of pharmacological and toxicological importance to the development and clinical use of drugs.

  10. Impact of Pregnancy on Zonisamide Pharmacokinetics in Rabbits

    Directory of Open Access Journals (Sweden)

    Kamal M. Matar

    2013-01-01

    Full Text Available Pregnancy is associated with various physiological changes which may lead to significant alterations in the pharmacokinetics of many drugs. The present study was aimed to investigate the potential effects of pregnancy on the pharmacokinetic profile of zonisamide (ZNM in the rabbit. Seven female rabbits were used in this study. The pregnant and nonpregnant rabbits received ZNM orally at a dose of 10 mg/kg and blood samples were collected from the animals just before receiving the drug and then serially for up to 24 h. The plasma samples were analyzed using tandem mass spectrometric method. Following a single oral dose of ZNM to the rabbits, the mean values of ZNM plasma concentrations at different times were consistently low in pregnant compared to nonpregnant rabbits. The mean values of ZNM’s Cmax and AUC0-∞ were significantly (P<0.05 decreased, whereas the CL/F exhibited substantial increase (P<0.05 in pregnant compared to nonpregnant rabbits. Tmax, t1/2abs, t1/2el, MRT, and Vd/F showed no significant differences between the two groups. The present study demonstrates that pregnancy decreased ZNM plasma concentrations in rabbits and that the decrease could be due to decreased extent of gastrointestinal absorption, induced hepatic metabolism, or enhanced renal elimination of the drug.

  11. Single-dose and steady-state pharmacokinetics of diltiazem administered in two different tablet formulations

    DEFF Research Database (Denmark)

    Christrup, Lona Louring; Bonde, J; Rasmussen, S N

    1992-01-01

    Single-dose and steady state pharmacokinetics of diltiazem administered in two different oral formulations were assessed with particular reference to rate and extent of absorption. Following single dose administration a significant difference in tmax was observed (2.9 +/- 1.9 and 6.8 +/- 2.6 hr r...

  12. Pharmacogenomic and clinical data link non-pharmacokinetic metabolic dysregulation to drug side effect pathogenesis

    DEFF Research Database (Denmark)

    Zielinski, Daniel C.; Filipp, F. V.; Bordbar, A.

    2015-01-01

    Drug side effects cause a significant clinical and economic burden. However, mechanisms of drug action underlying side effect pathogenesis remain largely unknown. Here, we integrate pharmacogenomic and clinical data with a human metabolic network and find that non-pharmacokinetic metabolic pathways...

  13. Pharmacokinetics and pharmacokinetic variability of heroin and its metabolites: review of the literature

    NARCIS (Netherlands)

    Rook, Elisabeth J.; Huitema, Alwin D. R.; van den Brink, Wim; van Ree, Jan M.; Beijnen, Jos H.

    2006-01-01

    This article reviews the pharmacokinetics of heroin after intravenous, oral, intranasal, intramuscular and rectal application and after inhalation in humans, with a special focus on heroin maintenance therapy in heroin dependent patients. In heroin maintenance therapy high doses pharmaceutically

  14. Pharmacokinetic of antimony in mice with cutaneous Leishmaniasis

    International Nuclear Information System (INIS)

    Borborema, Samanta E.T.; Nascimento, Nanci do; Osso Junior, Joao A.

    2007-01-01

    Cutaneous Leishmaniasis (CL) remains a major world health problem, with about 1.5 million new cases each year. Caused by protozoa Leishmania, in South America, this infection can vary from a chronic skin ulcer, to an erosive mucosal disease and severe facial disfigurement. Pentavalent antimony (Sb +5 ) as sodium stibogluconate (Pentostam) or meglumine antimoniate (Glucantime) are main drugs for treating most forms of human leishmaniasis. For six decades, despite the recent developments, the effective therapy to cutaneous leishmaniasis has been based on long parenteral courses of such drugs, even though these are fairly costly, toxic and inconvenient to use, without adequate knowledge on their pharmacokinetics or mechanism of action. Pharmacokinetics studies could be based on bioactive traceable drugs, usually with radioactive isotopes, but antimony radioisotopes are unavailable commercially. Neutron irradiation is a powerful tool in the analysis of mineral content of samples, for antimony, there are at least two main isotopes that could be formed after neutron irradiation in nuclear reactor. The aim of the present study was to construct antimony salts with those radioisotopes to obtain tracers to compare the pharmacokinetic and the tissue distribution of neutron irradiated meglumine antimoniate in healthy and cutaneous leishmaniasis experimentally infected mice. Meglumine antimoniate, (Glucantime, Aventis, S.P, Brazil), was neutron irradiated inside the IEA-R1 nuclear reactor (IPEN/CNEN-SP), producing two radioisotopes 122 Sb and 124 Sb. Its biodistribution was verified in BALB/c mice experimentally infected with Leishmania (Leishmania) Amazonensis, which received a single intraperitoneal dose of the drug. At different times after injection, the tissues and blood were excised and activity measured in a NaI (Tl) scintillation counter. Compared with the healthy mice, experimentally infected mice had significantly lower maximum concentration of antimony and high

  15. Pharmacokinetic of antimony in mice with cutaneous Leishmaniasis

    Energy Technology Data Exchange (ETDEWEB)

    Borborema, Samanta E.T.; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares IPEN/CNEN-SP, Sao Paulo, SP (Brazil). Lab. de Biologia Molecular]. E-mails: samanta@usp.br; nnascime@ipen.br; Andrade Junior, Heitor F. de [Instituto de Pesquisas Energeticas e Nucleares IPEN/CNEN-SP, Sao Paulo, SP (Brazil). Lab. de Biologia Molecular; Instituto de Medicina Tropical de Sao Paulo, Sao Paulo, SP (Brazil); E-mail: hfandrad@usp.br; Osso Junior, Joao A. [Instituto de Pesquisas Energeticas e Nucleares IPEN/CNEN-SP, Sao Paulo, SP (Brazil). Centro de Radiofarmacia]. E-mail: jaosso@ipen.br

    2007-07-01

    Cutaneous Leishmaniasis (CL) remains a major world health problem, with about 1.5 million new cases each year. Caused by protozoa Leishmania, in South America, this infection can vary from a chronic skin ulcer, to an erosive mucosal disease and severe facial disfigurement. Pentavalent antimony (Sb{sup +5}) as sodium stibogluconate (Pentostam) or meglumine antimoniate (Glucantime) are main drugs for treating most forms of human leishmaniasis. For six decades, despite the recent developments, the effective therapy to cutaneous leishmaniasis has been based on long parenteral courses of such drugs, even though these are fairly costly, toxic and inconvenient to use, without adequate knowledge on their pharmacokinetics or mechanism of action. Pharmacokinetics studies could be based on bioactive traceable drugs, usually with radioactive isotopes, but antimony radioisotopes are unavailable commercially. Neutron irradiation is a powerful tool in the analysis of mineral content of samples, for antimony, there are at least two main isotopes that could be formed after neutron irradiation in nuclear reactor. The aim of the present study was to construct antimony salts with those radioisotopes to obtain tracers to compare the pharmacokinetic and the tissue distribution of neutron irradiated meglumine antimoniate in healthy and cutaneous leishmaniasis experimentally infected mice. Meglumine antimoniate, (Glucantime, Aventis, S.P, Brazil), was neutron irradiated inside the IEA-R1 nuclear reactor (IPEN/CNEN-SP), producing two radioisotopes {sup 122}Sb and {sup 124}Sb. Its biodistribution was verified in BALB/c mice experimentally infected with Leishmania (Leishmania) Amazonensis, which received a single intraperitoneal dose of the drug. At different times after injection, the tissues and blood were excised and activity measured in a NaI (Tl) scintillation counter. Compared with the healthy mice, experimentally infected mice had significantly lower maximum concentration of antimony

  16. Pharmacokinetics difference of multiple active constituents from decoction and maceration of Fuzi Xiexin Tang after oral administration in rat by UPLC-MS/MS.

    Science.gov (United States)

    Zhang, Qian; Ma, Yue-ming; Wang, Zheng-tao; Wang, Chang-hong

    2014-04-01

    Fuzi Xiexin Tang (FXT) is a classic traditional Chinese medicine formula which has been employed in clinical for more than 1800 years. The distinctive preparation method (maceration) recorded in ancient time is different from one in modern clinical practice (decoction). Aim of this study is to investigate the pharmacokinetic difference of alkaloids, flavones and anthraquinones in rats after oral administration of decoction of FXT (DFXT, 30gkg(-1)), maceration of FXT (MFXT, 30gkg(-1)) and decoction of Aconiti Lateralis Radix Preparata (DAR, 6gkg(-1)) by a validated UPLC-MS/MS method. Plasma concentrations and pharmacokinetic parameters of 16 active constituents (aconitine, hypaconitine, mesaconitine, benzoylaconine, benzoylhypaconine, benzoylmesaconine, berberine, palmatine, jatrorrhizine, coptisine, baicalin, wogonin, wogonoside, emodin, aloe-emodin, rhein) in rat were quantified and compared. Different preparative methods resulted in significant difference on exposure and pharmacokinetic characteristics of alkaloids, flavones and anthraquinones from FXT, especially protoberberine alkaloids. Concentrations of monoester-diterpenoid alkaloids were below the LOD in rat plasma after administration of DFXT and MFXT because of the existence of other three herbs from FXT. Maceration could decrease the absorption of flavones while increased the absorption of anthraquinones. Cmax of emodin and rhein were 3.1 and 10.3 times increased, while eliminations of these two constituents were 8.0 and 19.0 times slower after administration of MFXT. Bioavailability of both flavones and anthraquinones increased after administration of MFXT, especially emodin and rhein increasing as much as 13.5 and 20.7 times. Herb-herb interaction between DAR and other three herbs from FXT significantly influenced the exposure of aconitum alkaloids. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Pharmacokinetics of mefloquine and its effect on sulfamethoxazole and trimethoprim steady-state blood levels in intermittent preventive treatment (IPTp) of pregnant HIV-infected women in Kenya.

    Science.gov (United States)

    Green, Michael; Otieno, Kephas; Katana, Abraham; Slutsker, Laurence; Kariuki, Simon; Ouma, Peter; González, Raquel; Menendez, Clara; ter Kuile, Feiko; Desai, Meghna

    2016-01-05

    Intermittent preventive treatment in pregnancy with sulfadoxine/pyrimethamine is contra-indicated in HIV-positive pregnant women receiving sulfamethoxazole/trimethoprim prophylaxis. Since mefloquine is being considered as a replacement for sulfadoxine/pyrimethamine in this vulnerable population, an investigation on the pharmacokinetic interactions of mefloquine, sulfamethoxazole and trimethoprim in pregnant, HIV-infected women was performed. A double-blinded, placebo-controlled study was conducted with 124 HIV-infected, pregnant women on a standard regimen of sulfamethoxazole/trimethoprim prophylaxis. Seventy-two subjects received three doses of mefloquine (15 mg/kg) at monthly intervals. Dried blood spots were collected from both placebo and mefloquine arms four to 672 h post-administration and on day 7 following a second monthly dose of mefloquine. A novel high-performance liquid chromatographic method was developed to simultaneously measure mefloquine, sulfamethoxazole and trimethoprim from each blood spot. Non-compartmental methods using a naïve-pooled data approach were used to determine mefloquine pharmacokinetic parameters. Sulfamethoxazole/trimethoprim prophylaxis did not noticeably influence mefloquine pharmacokinetics relative to reported values. The mefloquine half-life, observed clearance (CL/f), and area-under-the-curve (AUC0→∞) were 12.0 days, 0.035 l/h/kg and 431 µg-h/ml, respectively. Although trimethoprim steady-state levels were not significantly different between arms, sulfamethoxazole levels showed a significant 53% decrease after mefloquine administration relative to the placebo group and returning to pre-dose levels at 28 days. Although a transient decrease in sulfamethoxazole levels was observed, there was no change in hospital admissions due to secondary bacterial infections, implying that mefloquine may have provided antimicrobial protection.

  18. Population pharmacokinetics of adefovir dipivoxil tablets in healthy Chinese volunteers.

    Science.gov (United States)

    Huang, Jihan; Zhang, Yaping; Huang, Xiaohui; Li, Lujin; Li, Yunfei; Wang, Kun; Yang, Juan; He, Yingchun; Lv, Yinghua; Zheng, Qingshan

    2014-01-01

    To develop a population pharmacokinetic model of adefovir dipivoxil in healthy volunteers and evaluate the effect of individual factors on the pharmacokinetics of adefovir dipivoxil. Plasma concentration data collected from 32 healthy Chinese subjects in a Phase I clinical study was pooled. Subjects received a single oral dose of 10 mg, 20 mg, or 30 mg adefovir dipivoxil, or multiple doses of 10 mg once a day for 9 days. Plasma concentrations of adefovir dipivoxil were measured using a validated liquid chromatography-mass spectrometric method. A nonlinear mixed-effect model was used to analyze the plasma concentration data of adefovir dipivoxil in healthy volunteers and to calculate the relevant parameters as well as inter- and intra-individual variability. The time course of adefovir dipivoxil concentration is best described by a first-order absorption and first-order elimination two-compartment model with lag time. The final estimate of total body clearance (CL) is 56.9 L/h and 78.7 L/h for single and multiple dosing regimen, respectively; the volume distribution of the central compartment (V2) is 106 L; inter-compartmental clearance (Q) is 220 L/h; volume distribution of the peripheral compartment (V3) is 498 L and 800 L for single and multiple dosing regimen, respectively; absorption rate is 0.509 h-1; and lag time is 0.315 hours. The inter-individual variabilities of CL and V2 were 22.4% and 58.9%, respectively. The proportional error of residual variability is 14.1% and the additive error is 0.30 ng/L. The final pharmacokinetic model was evaluated using a bootstrap method. A nonlinear mixed effect model for oral adefovir dipivoxil formulations was developed in healthy Chinese subjects. A multiple dosing regimen may significantly increase the body clearance and volume distribution of the peripheral compartment compared to a single dosing regimen. *These authors contribute equally to this work.

  19. Pharmacokinetics of combined treatment with praziquantel and albendazole in neurocysticercosis

    Science.gov (United States)

    Garcia, Hector H; Lescano, Andres G; Lanchote, Vera L; Pretell, E Javier; Gonzales, Isidro; Bustos, Javier A; Takayanagui, Osvaldo M; Bonato, Pierina S; Horton, John; Saavedra, Herbert; Gonzalez, Armando E; Gilman, Robert H

    2011-01-01

    AIMS Neurocysticercosis is the most common cause of acquired epilepsy in the world. Antiparasitic treatment of viable brain cysts is of clinical benefit, but current antiparasitic regimes provide incomplete parasiticidal efficacy. Combined use of two antiparasitic drugs may improve clearance of brain parasites. Albendazole (ABZ) has been used together with praziquantel (PZQ) before for geohelminths, echinococcosis and cysticercosis, but their combined use is not yet formally recommended and only scarce, discrepant data exist on their pharmacokinetics when given together. We assessed the pharmacokinetics of their combined use for the treatment of neurocysticercosis. METHODS A randomized, double-blind, placebo-controlled phase II evaluation of the pharmacokinetics of ABZ and PZQ in 32 patients with neurocysticercosis was carried out. Patients received their usual concomitant medications including an antiepileptic drug, dexamethasone, and ranitidine. Randomization was stratified by antiepileptic drug (phenytoin or carbamazepine). Subjects had sequential blood samples taken after the first dose of antiparasitic drugs and again after 9 days of treatment, and were followed for 3 months after dosing. RESULTS Twenty-one men and 11 women, aged 16 to 55 (mean age 28) years were included. Albendazole sulfoxide concentrations were increased in the combination group compared with the ABZ alone group, both in patients taking phenytoin and patients taking carbamazepine. PZQ concentrations were also increased by the end of therapy. There were no significant side effects in this study group. CONCLUSIONS Combined ABZ + PZQ is associated with increased albendazole sulfoxide plasma concentrations. These increased concentrations could independently contribute to increased cysticidal efficacy by themselves or in addition to a possible synergistic effect. PMID:21332573

  20. Clinical Pharmacokinetics and Pharmacodynamics of Albiglutide

    DEFF Research Database (Denmark)

    Brønden, Andreas; Knop, Filip K; Christensen, Mikkel B

    2017-01-01

    Albiglutide is a long-acting, glucagon-like peptide-1 receptor agonist for subcutaneous administration with a recommended dose of 30-50 mg once weekly. The aim of this article is to outline the pharmacokinetic and pharmacodynamic properties of albiglutide including the clinical efficacy and safet...

  1. Glipizide Pharmacokinetics in Healthy and Diabetic Volunteers

    African Journals Online (AJOL)

    Erah

    Purpose: Disease state may contribute to alteration in drug pharmacokinetics. The purpose of this study was to determine the effect of non-insulin dependent diabetes mellitus (NIDDM) on the ... assayed using a sensitive and validated reverse phase high performance liquid ..... factors may contribute to these variations. [17].

  2. Pharmacological activities and pharmacokinetic study of hyperoside ...

    African Journals Online (AJOL)

    Studies on its pharmacokinetic (PK) properties revealed that it is a stable compound ... attention in drug discovery and food supplement research ... neurotrophic factor (BDNF) and cAMP response element ... antidepressant effect of hyperoside is mediated through .... Saposhnikovia divaricata by high performance counter-.

  3. The role of pharmacokinetics in risk assessment

    International Nuclear Information System (INIS)

    Reitz, R.H.; Fox, T.R.; Watanabe, P.G.

    1986-01-01

    Pharmacokinetics can aid in the formulation of risk estimations by selection of doses for toxicity studies, by distinguishing between ''internal dose or toxifor concentration'' and ''applied dose,'' by providing a physiological basis for extrapolating between species, and by helping us to visualize the toxicological consequences of processes which we cannot quantify. 10 refs., 6 figs., 2 tabs

  4. Human pharmacokinetics of proguanil and its metabolites

    DEFF Research Database (Denmark)

    Bygbjerg, Ib Christian; Ravn, P; Rønn, A

    1987-01-01

    The pharmacokinetics of proguanil and its metabolites cycloguanil and p-chlorophenylbiguanide were studied in five healthy volunteers taking 200 mg orally for 14 days. A highly sensitive and specific high-performance liquid chromatographic assay was applied, clearly identifying all three compounds...

  5. [Impact of ECMO on drugs pharmacokinetics].

    Science.gov (United States)

    Hasni, Nesrine; Lemaitre, Florian; Fernandez, Christine; Combes, Alain; Farinotti, Robert

    2011-01-01

    Extracorporeal membrane oxygenation (ECMO) is a life support system used in the treatment of patients of all ages with severe respiratory or cardiorespiratory failure. Despite the intensive use of drugs in the treatment of patients on ECMO, few studies have been conducted to determine the impact of this device on the pharmacokinetics of drugs. Publications in this field have shown pharmacokinetics changes resulting in an increase in volume of distribution of drugs and/or decreased clearance with consequent increase of their half-life. Reduced plasma concentrations of some drugs due to their adsorption on the different components of the circuit further complicates the determination of pharmacokinetic parameters of patients treated by ECMO. The literature published up to now on the pharmacokinetic changes associated with ECMO provide preliminary support for dosage adjustment. However, more research is needed to identify dosage strategies for this patient population. © 2011 Société Française de Pharmacologie et de Thérapeutique.

  6. Pharmacokinetics and pharmacodynamics of rhubarb anthraquinones extract in normal and disease rats.

    Science.gov (United States)

    Li, Peijin; Lu, Qianfeng; Jiang, Wenjiao; Pei, Xue; Sun, Yilin; Hao, Haiping; Hao, Kun

    2017-07-01

    Anthraquinones extract from Rheum palmatum L. (rhubarb) including rhein, emodin, aloe-emodin, chrysophanol, physcion and sennoside A, has been widely used in China to treat various diseases. This study was designed to explore the pharmacokinetic and pharmacodynamic properties of rhubarb anthraquinones extract in diabetic nephropathy and acute liver injury rats. The diabetic nephropathy and acute liver injury rats were induced by intraperitoneal injection with streptozotocin (STZ) and carbon tetrachloride (CCL 4 ), respectively. The rats were treated with different doses of rhubarb anthraquinones extract (37.5, 75 and 150mg/kg) as administration groups. For pharmacokinetics, the drug concentrations of rhubarb anthraquinones consisting of rhein, emodin, aloe-emodin, chrysophanol, physcion and sennoside A were determined. For pharmacodynamics, the anti-diabetic nephropathy and hepatoprotective effects were assessed under different dosage regimens. The rhein, emodin, aloe-emodin, chrysophanol were considered as pharmacokinetic markers at three doses of rhubarb anthraquinones extract. In diabetic nephropathy rats, no obvious pharmacokinetic change of the four ingredients was observed compared with control rats. However, the plasma exposures of the four ingredients increased in acute liver injury rats compared with control rats. The serum creatinine (SCr), blood urea nitrogen (BUN) and urine protein (UP) values in diabetic nephropathy rats decreased compared with those in the model group, which suggested that rhubarb anthraquinones extract displayed certain therapeutic and preventive effects against the diabetic nephropathy. However, rhubarb anthraquinones extract cannot ameliorate the CCL 4 -induced liver injury under the three different dosage regimens. There was no significant pharmacokinetic difference after a single oral administration of rhubarb anthraquinones extract between control and diabetic nephropathy rats. However, apparent pharmacokinetic differences were

  7. Pharmacokinetic parameters derived from dynamic contrast enhanced MRI of cervical cancers predict chemoradiotherapy outcome

    International Nuclear Information System (INIS)

    Andersen, Erlend K.F.; Hole, Knut Håkon; Lund, Kjersti V.; Sundfør, Kolbein; Kristensen, Gunnar B.; Lyng, Heidi; Malinen, Eirik

    2013-01-01

    Purpose: To assess the prognostic value of pharmacokinetic parameters derived from pre-chemoradiotherapy dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) of cervical cancer patients. Materials and methods: Seventy-eight patients with locally advanced cervical cancer underwent DCE-MRI with Gd-DTPA before chemoradiotherapy. The pharmacokinetic Brix and Tofts models were fitted to contrast enhancement curves in all tumor voxels, providing histograms of several pharmacokinetic parameters (Brix: A Brix , k ep , k el , Tofts: K trans , ν e ). A percentile screening approach including log-rank survival tests was undertaken to identify the clinically most relevant part of the intratumoral parameter distribution. Clinical endpoints were progression-free survival (PFS) and locoregional control (LRC). Multivariate analysis including FIGO stage and tumor volume was used to assess the prognostic significance of the imaging parameters. Results: A Brix , k el , and K trans were significantly (P e was significantly positively correlated with PFS only. k ep showed no association with any endpoint. A Brix was positively correlated with K trans and ν e , and showed the strongest association with endpoint in the log-rank testing. k el and K trans were independent prognostic factors in multivariate analysis with LRC as endpoint. Conclusions: Parameters estimated by pharmacokinetic analysis of DCE-MR images obtained prior to chemoradiotherapy may be used for identifying patients at risk of treatment failure

  8. Plasma pharmacokinetics after combined therapy of gemcitabine and oral S-1 for unresectable pancreatic cancer

    Directory of Open Access Journals (Sweden)

    Okita Yoshihiro

    2010-02-01

    Full Text Available Abstract Background The combination of gemcitabine (GEM and S-1, an oral 5-fluorouracil (5-FU derivative, has been shown to be a promising regimen for patients with unresectable pancreatic cancer. Methods Six patients with advanced pancreatic cancer were enrolled in this pharmacokinetics (PK study. These patients were treated by oral administration of S-1 30 mg/m2 twice daily for 28 consecutive days, followed by a 14-day rest period and intravenous administration of GEM 800 mg/m2 on days 1, 15 and 29 of each course. The PK parameters of GEM and/or 5-FU after GEM single-administration, S-1 single-administration, and co-administration of GEM with pre-administration of S-1 at 2-h intervals were analyzed. Results The maximum concentration (Cmax, the area under the curve from the drug administration to the infinite time (AUCinf, and the elimination half-life (T1/2 of GEM were not significantly different between GEM administration with and without S-1. The Cmax, AUCinf, T1/2, and the time required to reach Cmax (Tmax were not significantly different between S-1 administration with and without GEM. Conclusion There were no interactions between GEM and S-1 regarding plasma PK of GEM and 5-FU.

  9. Population pharmacokinetics of artesunate and amodiaquine in African children

    Directory of Open Access Journals (Sweden)

    Ouedraogo Alphonse

    2009-08-01

    Full Text Available Abstract Background Pharmacokinetic (PK data on amodiaquine (AQ and artesunate (AS are limited in children, an important risk group for malaria. The aim of this study was to evaluate the PK properties of a newly developed and registered fixed dose combination (FDC of artesunate and amodiaquine. Methods A prospective population pharmacokinetic study of AS and AQ was conducted in children aged six months to five years. Participants were randomized to receive the new artesunate and amodiaquine FDC or the same drugs given in separate tablets. Children were divided into two groups of 70 (35 in each treatment arm to evaluate the pharmacokinetic properties of AS and AQ, respectively. Population pharmacokinetic models for dihydroartemisinin (DHA and desethylamodiaquine (DeAq, the principal pharmacologically active metabolites of AS and AQ, respectively, and total artemisinin anti-malarial activity, defined as the sum of the molar equivalent plasma concentrations of DHA and artesunate, were constructed using the non-linear mixed effects approach. Relative bioavailability between products was compared by estimating the ratios (and 95% CI between the areas under the plasma concentration-time curves (AUC. Results The two regimens had similar PK properties in young children with acute malaria. The ratio of loose formulation to fixed co-formulation AUCs, was estimated as 1.043 (95% CI: 0.956 to 1.138 for DeAq. For DHA and total anti-malarial activity AUCs were estimated to be the same. Artesunate was rapidly absorbed, hydrolysed to DHA, and eliminated. Plasma concentrations were significantly higher following the first dose, when patients were acutely ill, than after subsequent doses when patients were usually afebrile and clinically improved. Amodiaquine was converted rapidly to DeAq, which was then eliminated with an estimated median (range elimination half-life of 9 (7 to 12 days. Efficacy was similar in the two treatments groups, with cure rates of 0

  10. Pharmacokinetics, efficacy prediction indexes and residue depletion of antibacterial drugs.

    Directory of Open Access Journals (Sweden)

    Arturo Anadón

    2016-06-01

    Full Text Available Pharmacokinetics behaviour of the antibacterial in food producing animals, provides information on the rates of absorption and elimination, half-life in plasma and tissue, elimination pathways and metabolism. The dose and the dosing interval of the antimicrobial can be justified by considering the pharmacokinetic/pharmacodynamic (PK/PD relationship, if established, as well as the severity of the disease, whereas the number of administrations should be in line with the nature of the disease. The target population for therapy should be well defined and possible to identify under field conditions. Based on in vitro susceptibility data, and target animal PK data, an analysis for the PK/PD relationship may be used to support dose regimen selection and interpretation criteria for a clinical breakpoint. Therefore, for all antibacterials with systemic activity, the MIC data collected should be compared with the concentration of the compound at the relevant biophase following administration at the assumed therapeutic dose as recorded in the pharmacokinetic studies. Currently, the most frequently used parameters to express the PK/PD relationship are Cmax/MIC (maximum serum concentration/MIC, %T > MIC (fraction of time in which concentration exceeds MIC and AUC/MIC (area under the inhibitory concentration– time curve/MIC. Furthermore, the pharmacokinetic parameters provide the first indication of the potential for persistent residues and the tissues in which they may occur. The information on residue depletion in food-producing animals, provides the data on which MRL recommendations will be based. A critical factor in the antibacterial medication of all food-producing animals is the mandatory withdrawal period, defined as the time during which drug must not be administered prior to the slaughter of the animal for consumption. The withdrawal period is an integral part of the regulatory authorities’ approval process and is designed to ensure that no

  11. The effect of respiratory disorders on clinical pharmacokinetic variables.

    Science.gov (United States)

    Taburet, A M; Tollier, C; Richard, C

    1990-12-01

    Respiratory disorders induce several pathophysiological changes involving gas exchange and acid-base balance, regional haemodynamics, and alterations of the alveolocapillary membrane. The consequences for the absorption, distribution and elimination of drugs are evaluated. Drug absorption after inhalation is not significantly impaired in patients. With drugs administered by this route, an average of 10% of the dose reaches the lungs. It is not completely clear whether changes in pulmonary endothelium in respiratory failure enhance lung absorption. The effects of changes in blood pH on plasma protein binding and volume of distribution are discussed, but relevant data are not available to explain the distribution changes observed in acutely ill patients. Lung diffusion of some antimicrobial agents is enhanced in patients with pulmonary infections. Decreased cardiac output and hepatic blood flow in patients under mechanical ventilation cause an increase in the plasma concentration of drugs with a high hepatic extraction ratio, such as lidocaine (lignocaine). On a theoretical basis, hypoxia should lead to decreased biotransformation of drugs with a low hepatic extraction ratio, but in vivo data with phenazone (antipyrine) or theophylline are conflicting. The effects of disease on the lung clearance of drugs are discussed but clinically relevant data are lacking. The pharmacokinetics of drugs in patients with asthma or chronic obstructive pulmonary disease are reviewed. Stable asthma and chronic obstructive pulmonary disease do not appear to affect the disposition of theophylline or beta 2-agonists such as salbutamol (albuterol) or terbutaline. Important variations in theophylline pharmacokinetics have been reported in critically ill patients, the causes of which are more likely to be linked to the poor condition of the patients than to a direct effect of hypoxia or hypercapnia. Little is known regarding the pharmacokinetics of cromoglycate, ipratropium, corticoids or

  12. Murine Efficacy and Pharmacokinetic Evaluation of the Flaviviral NS5 Capping Enzyme 2-Thioxothiazolidin-4-One Inhibitor BG-323.

    Science.gov (United States)

    Bullard, Kristen M; Gullberg, Rebekah C; Soltani, Elnaz; Steel, J Jordan; Geiss, Brian J; Keenan, Susan M

    2015-01-01

    Arthropod-borne flavivirus infection continues to cause significant morbidity and mortality worldwide. Identification of drug targets and novel antiflaviviral compounds to treat these diseases has become a global health imperative. A previous screen of 235,456 commercially available small molecules identified the 2-thioxothiazolidin-4-one family of compounds as inhibitors of the flaviviral NS5 capping enzyme, a promising target for antiviral drug development. Rational drug design methodologies enabled identification of lead compound BG-323 from this series. We have shown previously that BG-323 potently inhibits NS5 capping enzyme activity, displays antiviral effects in dengue virus replicon assays and inhibits growth of West Nile and yellow fever viruses with low cytotoxicity in vitro. In this study we further characterized BG-323's antiviral activity in vitro and in vivo. We found that BG-323 was able to reduce replication of WNV (NY99) and Powassan viruses in culture, and we were unable to force resistance into WNV (Kunjin) in long-term culture experiments. We then evaluated the antiviral activity of BG-323 in a murine model. Mice were challenged with WNV NY99 and administered BG-323 or mock by IP inoculation immediately post challenge and twice daily thereafter. Mice were bled and viremia was quantified on day three. No significant differences in viremia were observed between BG-323-treated and control groups and clinical scores indicated both BG-323-treated and control mice developed signs of illness on approximately the same day post challenge. To determine whether differences in in vitro and in vivo efficacy were due to unfavorable pharmacokinetic properties of BG-323, we conducted a pharmacokinetic evaluation of this small molecule. Insights from pharmacokinetic studies indicate that BG-323 is cell permeable, has a low efflux ratio and does not significantly inhibit two common cytochrome P450 (CYP P450) isoforms thus suggesting this molecule may be less

  13. Murine Efficacy and Pharmacokinetic Evaluation of the Flaviviral NS5 Capping Enzyme 2-Thioxothiazolidin-4-One Inhibitor BG-323.

    Directory of Open Access Journals (Sweden)

    Kristen M Bullard

    Full Text Available Arthropod-borne flavivirus infection continues to cause significant morbidity and mortality worldwide. Identification of drug targets and novel antiflaviviral compounds to treat these diseases has become a global health imperative. A previous screen of 235,456 commercially available small molecules identified the 2-thioxothiazolidin-4-one family of compounds as inhibitors of the flaviviral NS5 capping enzyme, a promising target for antiviral drug development. Rational drug design methodologies enabled identification of lead compound BG-323 from this series. We have shown previously that BG-323 potently inhibits NS5 capping enzyme activity, displays antiviral effects in dengue virus replicon assays and inhibits growth of West Nile and yellow fever viruses with low cytotoxicity in vitro. In this study we further characterized BG-323's antiviral activity in vitro and in vivo. We found that BG-323 was able to reduce replication of WNV (NY99 and Powassan viruses in culture, and we were unable to force resistance into WNV (Kunjin in long-term culture experiments. We then evaluated the antiviral activity of BG-323 in a murine model. Mice were challenged with WNV NY99 and administered BG-323 or mock by IP inoculation immediately post challenge and twice daily thereafter. Mice were bled and viremia was quantified on day three. No significant differences in viremia were observed between BG-323-treated and control groups and clinical scores indicated both BG-323-treated and control mice developed signs of illness on approximately the same day post challenge. To determine whether differences in in vitro and in vivo efficacy were due to unfavorable pharmacokinetic properties of BG-323, we conducted a pharmacokinetic evaluation of this small molecule. Insights from pharmacokinetic studies indicate that BG-323 is cell permeable, has a low efflux ratio and does not significantly inhibit two common cytochrome P450 (CYP P450 isoforms thus suggesting this molecule

  14. Pharmacokinetic aspects of the anti-epileptic drug substance vigabatrin

    DEFF Research Database (Denmark)

    Nøhr, Martha Kampp; Frølund, Sidsel; Holm, René

    2014-01-01

    are discussed in detail. Special focus is on the contribution of the proton-coupled amino acid transporter 1 (PAT1) for intestinal vigabatrin absorption. Furthermore, the review gives an overview of the pharmacokinetic parameters of vigabatrin across different species and drug-food and drug-drug interactions......Drug transporters in various tissues, such as intestine, kidney, liver and brain, are recognized as important mediators of absorption, distribution, metabolism and excretion of drug substances. This review gives a current status on the transporter(s) mediating the absorption, distribution......, metabolism and excretion properties of the anti-epileptic drug substance vigabatrin. For orally administered drugs, like vigabatrin, the absorption from the intestine is a prerequisite for the bioavailability. Therefore, transporter(s) involved in the intestinal absorption of vigabatrin in vitro and in vivo...

  15. Pharmacokinetic, Pharmacogenetic, and Other Factors Influencing CNS Penetration of Antiretrovirals

    Directory of Open Access Journals (Sweden)

    Jacinta Nwamaka Nwogu

    2016-01-01

    Full Text Available Neurological complications associated with the human immunodeficiency virus (HIV are a matter of great concern. While antiretroviral (ARV drugs are the cornerstone of HIV treatment and typically produce neurological benefit, some ARV drugs have limited CNS penetration while others have been associated with neurotoxicity. CNS penetration is a function of several factors including sieving role of blood-brain and blood-CSF barriers and activity of innate drug transporters. Other factors are related to pharmacokinetics and pharmacogenetics of the specific ARV agent or mediated by drug interactions, local inflammation, and blood flow. In this review, we provide an overview of the various factors influencing CNS penetration of ARV drugs with an emphasis on those commonly used in sub-Saharan Africa. We also summarize some key associations between ARV drug penetration, CNS efficacy, and neurotoxicity.

  16. Moxifloxacin pharmacokinetics and pleural fluid penetration in patients with pleural effusion.

    Science.gov (United States)

    Chatzika, Kalliopi; Manika, Katerina; Kontou, Paschalina; Pitsiou, Georgia; Papakosta, Despina; Zarogoulidis, Konstantinos; Kioumis, Ioannis

    2014-01-01

    The aim of this study was to evaluate the pharmacokinetics and penetration of moxifloxacin (MXF) in patients with various types of pleural effusion. Twelve patients with empyema/parapneumonic effusion (PPE) and 12 patients with malignant pleural effusion were enrolled in the study. A single-dose pharmacokinetic study was performed after intravenous administration of 400 mg MXF. Serial plasma (PL) and pleural fluid (PF) samples were collected during a 24-h time interval after drug administration. The MXF concentration in PL and PF was determined by high-performance liquid chromatography, and main pharmacokinetic parameters were estimated. Penetration of MXF in PF was determined by the ratio of the area under the concentration-time curve from time zero to 24 h (AUC24) in PF (AUC24PF) to the AUC24 in PL. No statistically significant differences in the pharmacokinetics in PL were observed between the two groups, despite the large interindividual variability in the volume of distribution, clearance, and elimination half-life. The maximum concentration in PF (CmaxPF) in patients with empyema/PPE was 2.23±1.31 mg/liter, and it was detected 7.50±2.39 h after the initiation of the infusion. In patients with malignant effusion, CmaxPF was 2.96±1.45 mg/liter, but it was observed significantly earlier, at 3.58±1.38 h (Ppleural effusion.

  17. The effect of age on digoxin pharmacokinetics in Fischer-344 rats

    International Nuclear Information System (INIS)

    Evans, R.L.; Owens, S.M.; Ruch, S.; Kennedy, R.H.; Seifen, E.

    1990-01-01

    Digoxin protein binding and pharmacokinetics were studied in 4-, 14-, and 25-month-old male Fischer-344 rats to determine if there were age-dependent changes in digoxin disposition. Serum protein binding did not differ among age groups. The average percentage unbound digoxin for all animals was 61.3 ± 5.3% (means ± SD, n = 15). For pharmacokinetic studies, [ 3 H]digoxin and 1 mg/kg unlabeled digoxin were administered as an intravenous bolus dose to animals from each age group. The [ 3 H]digoxin terminal elimination half-life was 2.0, 2.3, and 2.5 hr, respectively. The steady-state volume of distribution in the three age groups was 1.51, 1.49, and 1.27 liters/kg, respectively. Total body clearance for the three age groups was 14.2, 12.1, and 7.5 ml/min/kg, respectively. Analysis of variance of these data followed by Duncan's multiple range test indicated a significant decrease in clearance in the aged rats (25-month-old, p less than 0.05). This age-dependent decrease in clearance suggested that digoxin pharmacokinetics could be a significant factor in age-related alterations in digoxin cardiotoxicity in the rat, as it is in humans, and that the Fischer-344 rat could be a useful model for studies of digoxin pharmacokinetic changes with age

  18. "THE EVALUATION OF THE POSSIBLE EFFECT OF POSITIVE END EXPIRATORY PRESSURE (PEEP ON PHARMACOKINETICS OF PHENYTOIN IN PATIENTS WITH ACUTE BRAIN INJURY UNDER MECHANICAL VENTILATION."

    Directory of Open Access Journals (Sweden)

    "Elham Hadidi

    2005-04-01

    Full Text Available Positive ventilation has shown to have an influence on pharmacokinetic and disposition of some drugs.Beacause phenytoin with a narrow therapautic range, is the most commonly used drug for prophylaxis and treatment of early seizures after acute brain injuries, in the present study the effect of short term PEEP (5-10 cm H2O for at least 8 hours on phenytoin serum concentration and pharmacokinetic parameters such as Vmax and clearance in brain injured patients under mechanical ventilation was examined. Ten patients with moderate to severe acute brain injury who were placed on mechanical ventilation with an initial PEEP level of 0-5 cm H2O were included in the study. Patients received phenytoin loading dose of 15 mg/kg followed by a maintenance daily dose of 3-7 mg/kg initiated within 12 hours of loading dose. Sampels were taken on two different occasions before and after PEEP elevation. Total phenytoin serum concentrations were determined by HPLC method. A time invarient Michaelis-Menten pharmacokinetic model was used to calculate Vmax and clearance for each patient.Derrived variables were calculated as follows: Vmax, 3.5-6.8 and 3.7-8.2 mg/kg/day; Clearance, 0.1-0.7 and 0.1-1.2 l/kg/day (before and after PEEP elevation, respectively. Our data have shown a wide range of variability (2.6-32.5 mg/l in phenytoin serum concentrations. There were no statistically significant differences in the measured total concentrations (p=0.721 and calculated Vmax and clearance (p=0.285before and after PEEP elevation. Administration of fluid and inotropic agents, limitation in application of higher levels of PEEP and drug interactions, shall be considered as possible explanations for these findings.

  19. LC-MS/MS Determination and Pharmacokinetic Study of Pedunculoside in Rat Plasma after Oral Administration of Pedunculoside and Ilex rotunda Extract

    Directory of Open Access Journals (Sweden)

    Waiou Zhao

    2015-05-01

    Full Text Available Ilex rotunda is widely used to treat many disorders as a traditional Chinese medicine (TCM containing 4%–5% pedunculoside (PDC. A rapid, selective, and sensitive liquid chromatography-tandem mass spectrometry method (LC-MS/MS was developed and validated to determine PDC in rat plasma by using 3β,19α-dihydroxyurs-12-en-28-oic acid 28-β-D-glucopyranosyl ester (DEOG as an internal standard. The analytes were extracted by protein precipitation and eluted on a C18 chromatography column using a mobile phase of methanol–H2O (70:30, v/v delivered at a flow rate of 0.6 mL/min. Detection was performed using positive ion electrospray ionization in multiple reaction monitoring modes. The assay was linear over the concentration range of 0.60 ng/mL to 200 ng/mL, with a quantification limit of 0.60 ng/mL. Intra-day and inter-day precisions (%RSD ranged from 2.12 to 9.51 for PDC, whereas the accuracy was within −7.83%~9.40%. The validated method was successfully applied to the pharmacokinetic study of PDC in rat plasma after oral administration of pure PDC and Ilex rotunda extract (IRE. Pharmacokinetic parameters of PDC in IRE, such as Cmax, AUC0–t, AUC0–∞, t1/2z, and CLz/F, statistically differed from those of the pure monomer (p < 0.01. However, Tmax and MRT showed no significant differences between the two groups. Results suggested that other coexisting components in IRE may decrease the absorption of PDC. Compound-compound interactions between PDC and other herbal extract components can alter the pharmacokinetic behavior of PDC. The study will be helpful in providing references for understanding the action mechanism and clinical application of Ilex rotunda.

  20. Dose study of the multikinase inhibitor, LY2457546, in patients with relapsed acute myeloid leukemia to assess safety, pharmacokinetics, and pharmacodynamics

    International Nuclear Information System (INIS)

    Wacheck, Volker; Lahn, Michael; Dickinson, Gemma; Füreder, Wolfgang; Meyer, Renata; Herndlhofer, Susanne; Füreder, Thorsten; Dorfner, Georg; Pillay, Sada; André, Valérie; Burkholder, Timothy P; Akunda, Jacqueline K; Flye-Blakemore, Leann; Van Bockstaele, Dirk; Schlenk, Richard F; Sperr, Wolfgang R; Valent, Peter

    2011-01-01

    Acute myeloid leukemia (AML) is a life-threatening malignancy with limited treatment options in chemotherapy-refractory patients. A first-in-human dose study was designed to investigate a safe and biologically effective dose range for LY2457546, a novel multikinase inhibitor, in patients with relapsed AML. In this nonrandomized, open-label, dose escalation Phase I study, LY2457546 was administered orally once a day. Safety, pharmacokinetics, changes in phosphorylation of target kinases in AML blasts, and risk of drug–drug interactions (DDI) were assessed. Five patients were treated at the starting and predicted minimal biologically effective dose of 50 mg/day. The most commonly observed adverse events were febrile neutropenia, epistaxis, petechiae, and headache. The majority of adverse events (81%) were Grade 1 or 2. One patient had generalized muscle weakness (Grade 3), which was deemed to be a dose-limiting toxicity. Notably, the pharmacokinetic profile of LY2457546 showed virtually no elimination of LY2457546 within 24 hours, and thus prevented further dose escalation. No significant DDI were observed. Ex vivo flow cytometry studies showed downregulation of the phosphoproteins, pcKIT, pFLT3, and pS6, in AML blasts after LY2457546 administration. No medically relevant responses were observed in the five treated patients. No biologically effective dose could be established for LY2457546 in chemotherapy-resistant AML patients. Lack of drug clearance prevented safe dose escalation, and the study was terminated early. Future efforts should be made to develop derivatives with a more favorable pharmacokinetic profile

  1. Pharmacokinetics and toxicology of therapeutic proteins: Advances and challenges

    Science.gov (United States)

    Vugmeyster, Yulia; Xu, Xin; Theil, Frank-Peter; Khawli, Leslie A; Leach, Michael W

    2012-01-01

    Significant progress has been made in understanding pharmacokinetics (PK), pharmacodynamics (PD), as well as toxicity profiles of therapeutic proteins in animals and humans, which have been in commercial development for more than three decades. However, in the PK arena, many fundamental questions remain to be resolved. Investigative and bioanalytical tools need to be established to improve the translation of PK data from animals to humans, and from in vitro assays to in vivo readouts, which would ultimately lead to a higher success rate in drug development. In toxicology, it is known, in general, what studies are needed to safely develop therapeutic proteins, and what studies do not provide relevant information. One of the major complicating factors in nonclinical and clinical programs for therapeutic proteins is the impact of immunogenicity. In this review, we will highlight the emerging science and technology, as well as the challenges around the pharmacokinetic- and safety-related issues in drug development of mAbs and other therapeutic proteins. PMID:22558487

  2. The influence of stereoisomerism on the pharmacokinetics of Tc radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, L.; Taylor, A. [Atlanta, Emory Univ. School of Medicine, GA (United States). Dept. of Chemistry; Marzilli, L.G. [Atlanta, Emory Univ. School of Medicine, GA (United States). Dept. of Radiology

    1998-12-01

    The influence of stereoisomerism on the pharmacokinetics of Tc mono-oxo complexes is reviewed. Tc(V) mono-oxo complexes formed with N/S ligands have four donor groups from the ligands in an equatorial plane; the oxo ligand coordinates in an axial position. Stereoisomerism in Tc(V) mono-oxo complexes can be centered within the ligand (carbon atom in the chelate ring of ligating nitrogen of amine donors) or at the Tc. The metal center becomes chiral when an equatorial ligand has a head and a tail (i.e. the two ends of the ligand differ). All types of stereocenter can produce significantly different pharmacokinetic profiles for individual isomers. Thus, biological evaluation of separated stereoisomers is necessary to identify the optimal stereochemical configuration, particularly for radiopharmaceuticals targeted to receptor molecules with low specificity. Because of inter species variation, there is ultimately no substitute for human testing. Although it is possible that the increase in nonspecific binding of agents incorporating L- vs D-amino acids may more than offset any increased receptor binding, much more information is needed. Stereochemical factors can also lead to unpredictable differences in coordination geometry and thermodynamic preference of a single isomer; thus chemical characterization of stereo-isomers continues to be an important component of radiopharmaceutical development.

  3. Pharmacokinetics of paracetamol in chicks treated with metronidazole

    Directory of Open Access Journals (Sweden)

    S.M. Hussain

    2017-06-01

    Full Text Available Effect of metronidazole on the pharmacokinetics of paracetamol were examined in chicks. Chicks were dosed orally with metronidazole at 350 mg\\kg of body weight daily (10 -13 days of age. On the last day of metronidazole dosing, chicks injected intraperitoneally with paracetamol at of 50 mg\\kg of body weight. Paracetamol appeared in chick plasma at 52.00, 45.00, 40.75, 32.75, 23.25 µg \\ml after 0.25, 0.50, 0.75, 1, 2, 4 hours of injection respectively. A significantly decreased the concentration paracetamol at times of 0.25, 0.50, 0.75, 1, 4 hours post injection and appeared at concentrations of 36.62, 35.37, 25.62, 20.50, 11.00 µg\\ml. These was reflected by changes in the pharmacokinetics of paracetamol as show by the increase elimination rate constant (48% and decrease in the half-life (32 % and increase in volume distribution (29% and increase in clearance by (96% and decrease in the area under the plasma curve (33% and decrease in the area under moment curve 65% and lack mean residence time (33%. These results indicate that oral dosing of chicks with metronidazole for four consecutive days and this effect increase in the elemination rate of paracetamol and this effect must be considered when therapy with paracetamol when given during metronidazole therapy.

  4. Mixed Effects Modeling Using Stochastic Differential Equations: Illustrated by Pharmacokinetic Data of Nicotinic Acid in Obese Zucker Rats.

    Science.gov (United States)

    Leander, Jacob; Almquist, Joachim; Ahlström, Christine; Gabrielsson, Johan; Jirstrand, Mats

    2015-05-01

    Inclusion of stochastic differential equations in mixed effects models provides means to quantify and distinguish three sources of variability in data. In addition to the two commonly encountered sources, measurement error and interindividual variability, we also consider uncertainty in the dynamical model itself. To this end, we extend the ordinary differential equation setting used in nonlinear mixed effects models to include stochastic differential equations. The approximate population likelihood is derived using the first-order conditional estimation with interaction method and extended Kalman filtering. To illustrate the application of the stochastic differential mixed effects model, two pharmacokinetic models are considered. First, we use a stochastic one-compartmental model with first-order input and nonlinear elimination to generate synthetic data in a simulated study. We show that by using the proposed method, the three sources of variability can be successfully separated. If the stochastic part is neglected, the parameter estimates become biased, and the measurement error variance is significantly overestimated. Second, we consider an extension to a stochastic pharmacokinetic model in a preclinical study of nicotinic acid kinetics in obese Zucker rats. The parameter estimates are compared between a deterministic and a stochastic NiAc disposition model, respectively. Discrepancies between model predictions and observations, previously described as measurement noise only, are now separated into a comparatively lower level of measurement noise and a significant uncertainty in model dynamics. These examples demonstrate that stochastic differential mixed effects models are useful tools for identifying incomplete or inaccurate model dynamics and for reducing potential bias in parameter estimates due to such model deficiencies.

  5. A Review on Pharmacokinetic Modeling and the Effects of Environmental Stressors on Pharmacokinetics for Operational Medicine: Operational Pharmacokinetics

    Science.gov (United States)

    2009-09-01

    Manning et al. 1986), which may cause physiological changes. For example, emotional distress may lead to elevated heart rate, blood pressure and...related changes in renal functions were reported during a Stroop word color conflict test (Fauvel, Hadj-Aissa et al. 1991). Emotional stressors could...M. Skee, et al. (2001). "Pharmacokinetics of norelgestromin and ethinyl estradiol delivered by a contraceptive patch (Ortho Evra (TM)/Evra (TM

  6. Sex- and dose-dependency in the pharmacokinetics and pharmacodynamics of (+)-methamphetamine and its metabolite (+)-amphetamine in rats

    International Nuclear Information System (INIS)

    Milesi-Halle, Alessandra; Hendrickson, Howard P.; Laurenzana, Elizabeth M.; Gentry, W. Brooks; Owens, S. Michael

    2005-01-01

    These studies investigated how (+)-methamphetamine (METH) dose and rat sex affect the pharmacological response to METH in Sprague-Dawley rats. The first set of experiments determined the pharmacokinetics of METH and its pharmacologically active metabolite (+)-amphetamine (AMP) in male and female Sprague-Dawley rats after 1.0 and 3.0 mg/kg METH doses. The results showed significant sex-dependent changes in METH pharmacokinetics, and females formed significantly lower amounts of AMP. While the area under the serum concentration-time curve in males increased proportionately with the METH dose, the females showed a disproportional increase. The sex differences in systemic clearance, renal clearance, volume of distribution, and percentage of unchanged METH eliminated in the urine suggested dose-dependent pharmacokinetics in female rats. The second set of studies sought to determine the behavioral implications of these pharmacokinetic differences by quantifying locomotor activity in male and female rats after saline, 1.0, and 3.0 mg/kg METH. The results showed sex- and dose-dependent differences in METH-induced locomotion, including profound differences in the temporal profile of effects at higher dose. These findings show that the pharmacokinetic and metabolic profile of METH (slower METH clearance and lower AMP metabolite formation) plays a significant role in the differential pharmacological response to METH in male and female rats

  7. Pharmacokinetic Interaction between Magnolol and Piperine in Rats

    African Journals Online (AJOL)

    Medicine, Dongguan, 523808, Peoples Republic of China. *For correspondence: Email: .... stability, according to the principles of the US. Food and Drug Administration .... P-glycoprotein (P-gp) as the drug export pump, is important for the ...

  8. Clinical Pharmacokinetic Interactions between Herbal Supplements and Anticancer Drugs

    NARCIS (Netherlands)

    Goey, A.K.L.

    2013-01-01

    In cancer treatment the response to chemotherapy is often characterized by a wide interpatient variability. The increasing popularity of herbal supplements among cancer patients may contribute to this phenomenon. Since these supplements may affect drug metabolizing cytochrome P450 (CYP) enzymes,

  9. Safety, tolerability and pharmacokinetics of doravirine, a novel HIV non-nucleoside reverse transcriptase inhibitor, after single and multiple doses in healthy subjects.

    Science.gov (United States)

    Anderson, Matt S; Gilmartin, Jocelyn; Cilissen, Caroline; De Lepeleire, Inge; Van Bortel, Luc; Dockendorf, Marissa F; Tetteh, Ernestina; Ancona, June K; Liu, Rachael; Guo, Ying; Wagner, John A; Butterton, Joan R

    2015-01-01

    Doravirine is a novel non-nucleoside inhibitor of HIV-1 reverse transcriptase with potent activity against wild-type virus (95% inhibitory concentration 19 nM, 50% human serum). Doravirine has low potential to cause drug-drug interactions since it is primarily eliminated by oxidative metabolism and does not inhibit or significantly induce drug-metabolizing enzymes. The pharmacokinetics and safety of doravirine were investigated in two double-blind, dose-escalation studies in healthy males. Thirty-two subjects received single doses of doravirine (6-1,200 mg) or matching placebo tablets; 40 subjects received doravirine (30-750 mg) or matching placebo tablets once daily for 10 days. In addition, the effect of doravirine (120 mg for 14 days) on single-dose pharmacokinetics of the CYP3A substrate midazolam was evaluated (10 subjects). The maximum plasma concentration (Cmax) of doravirine was achieved within 1-5 h with an apparent terminal half-life of 12-21 h. Consistent with single-dose pharmacokinetics, steady state was achieved after approximately 7 days of once daily administration, with accumulation ratios (day 10/day 1) of 1.1-1.5 in the area under the plasma concentration-time curve during the dosing interval (AUC0-24 h), Cmax and trough plasma concentration (C24 h). All dose levels produced C24 h>19 nM. Administration of 50 mg doravirine with a high-fat meal was associated with slight elevations in AUC time zero to infinity (AUC0-∞) and C24 h with no change in Cmax. Midazolam AUC0-∞ was slightly reduced by coadministration of doravirine (geometric mean ratio 0.82, 90% CI 0.70, 0.97). There was no apparent relationship between adverse event frequency or intensity and doravirine dose. No rash or significant central nervous system events other than headache were reported. Doravirine is generally well tolerated in single doses up to 1,200 mg and multiple doses up to 750 mg once daily for up to 10 days, with a pharmacokinetic profile supportive of once

  10. PHARMACOKINETICS OF PIROXICAM IN CRANES (FAMILY GRUIDAE).

    Science.gov (United States)

    Keiper, Naomi L; Cox, Sherry K; Doss, Grayson A; Elsmo, Betsy; Franzen-Klein, Dana; Hartup, Barry K

    2017-09-01

    To investigate the pharmacokinetics of the nonsteroidal anti-inflammatory drug (NSAID) piroxicam in cranes, three brolgas (Antigone rubicunda) were administered piroxicam as a single oral dose at 0.5 mg/kg and 1.0 mg/kg during separate trials. Serial blood samples were collected for quantification of piroxicam in plasma. Piroxicam was readily absorbed at both dosages, and no adverse effects were observed. Plasma concentrations peaked at 3.67 hr with a concentration of 4.00 μg/ml for the lower dosage, and at 0.83 hr at 8.77 μg/ml for the higher dosage. Piroxicam may exhibit linear kinetics and dose proportionality in brolgas, but will require further study. Mean peak plasma concentrations in brolgas were comparable to concentrations demonstrated to be analgesic in humans. To the authors' knowledge, this study represents the first pharmacokinetic investigation of piroxicam in an avian species.

  11. Pharmacokinetics of Alternative Administration Routes of Melatonin

    DEFF Research Database (Denmark)

    Zetner, D.; Andersen, L. P.H.; Rosenberg, J.

    2016-01-01

    Background: Melatonin is traditionally administered orally but has a poor and variable bioavailability. This study aims to present an overview of studies investigating the pharmacokinetics of alternative administration routes of melatonin. Methods: A systematic literature search was performed...... and included experimental or clinical studies, investigating pharmacokinetics of alternative administration routes of melatonin in vivo. Alternative administration routes were defined as all administration routes except oral and intravenous. Results: 10 studies were included in the review. Intranasal....... Subcutaneous injection of melatonin displayed a rapid absorption rate compared to oral administration. Conclusion: Intranasal administration of melatonin has a large potential, and more research in humans is warranted. Transdermal application of melatonin has a possible use in a local application, due to slow...

  12. Tubocurarine and pancuronium: a pharmacokinetic view.

    Science.gov (United States)

    Shanks, C A; Somogyi, A A; Ramzan, M I; Triggs, E J

    1980-02-01

    This review is an attempt to bring together the pharmacokinetic data on d-tubocurarine and pancuronium with clinical observations on relaxant dosage and effect. The modelling techniques used here represent an oversimplification of the relationships between relaxant plasma concentration and response as they do not predict either the time of onset of paralysis or its peak intensity. However, they do enable calculation of a bolus dose of relaxant required to achieve a particular intensity of paralysis for the average patient once pseudo-distribution equilibrium has been achieved. This has been further extended to predict the cumulation of the relaxants with subsequent dosage in average patients. Suggested regimens incorporating bolus and infusion doses of the relaxants to achieve continuous neuromuscular blockade have been calculated also. Averaged pharmacokinetic parameters derived from patients with renal or hepatic dysfunction have been used to predict the likely duration and intensities of paralysis for the relaxants.

  13. Impact of Drug Metabolism/Pharmacokinetics and Their Relevance upon Taxus-based Drug Development.

    Science.gov (United States)

    Hao, Da-Cheng; Ge, Guang-Bo; Wang, Ping; Yang, Ling

    2018-05-22

    Drug metabolism and pharmacokinetic (DMPK) studies of Taxus natural products, their semi-synthetic derivatives and analogs are indispensable in the optimization of lead compounds and clinical therapy. These studies can lead to development of new drug entities with improved absorption, distribution, metabolism, excretion and toxicity (ADME/T) profiles. To date, there have been no comprehensive reviews of the DMPK features of Taxus derived medicinal compounds.Natural and semi-synthetic taxanes may cause and could be affected by drug-drug interaction (DDI). Hence ADME/T studies of various taxane-containing formulations are important; to date these studies indicate that the role of cytochrome p450s and drug transporters is more prominent than phase II drug metabolizing enzymes. Mechanisms of taxane DMPK mediated by nuclear receptors, microRNAs, and single nucleotide polymorphisms are being revealed. Herein we review the latest knowledge on these topics, as well as the gaps in knowledge of the DMPK issues of Taxus compounds. DDIs significantly impact the PK/pharmacodynamics performance of taxanes and co-administered chemicals, which may inspire researchers to develop novel formula. While the ADME/T profiles of some taxanes are well defined, DMPK studies should be extended to more Taxus compounds, species, and Taxus -involved formulations, which would be streamlined by versatile omics platforms and computational analyses. Further biopharmaceutical investigations will be beneficial tothe translation of bench findings to the clinical applications. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  14. Solid lipid nanoparticles as promising tool for intraocular tobramycin delivery: Pharmacokinetic studies on rabbits.

    Science.gov (United States)

    Chetoni, Patrizia; Burgalassi, Susi; Monti, Daniela; Tampucci, Silvia; Tullio, Vivian; Cuffini, Anna Maria; Muntoni, Elisabetta; Spagnolo, Rita; Zara, Gian Paolo; Cavalli, Roberta

    2016-12-01

    Eye drops are widely accepted as formulations for targeting the anterior segment notwithstanding their limitations in terms of bioavailability. The unique structure of the eye requires specially-designed formulations able to favor the pharmacokinetic profile of administered drugs, mainly minimizing the influence of ocular barriers. Nanotechnology-based delivery systems lead to significant technological and therapeutical advantages in ophthalmic therapy. The aim of the present study was to determine whether tobramycin as ion-pair incorporated in mucoadhesive Solid Lipid Nanoparticles (SLN) reaches the inner parts of the eye favoring drug activity. After technological characterization of the tobramycin entrapped SLN formulation (Tobra-SLN), a pharmacokinetic study in rabbits after topical instillation and intravenous administration of the formulation has been carried out. In addition, the intracellular activity of Tobra-SLN formulation against phagocytosed Pseudomonas aeruginosa was investigated. The SLN were spherical in shape, and showed a hydrodynamic diameter of about 80nm, a negative zeta potential (-25.7mV) with a polydispersity index of 0.15, representative of a colloidal dispersion with high quality, characterized by an unimodal relatively narrow size distribution. As demonstrated by FTIR and DSC, tobramycin ion-pair could be concentrated into lipid inner core of SLN, without interaction with the stearic acid, thus promoting a slow and constant drug release profile in the dissolution medium. Surprisingly, the drug concentration was significantly higher in all ocular tissues after ocular and intravenous administration of Tobra-SLN formulation with respect to reference formulations and only Tobra-SLN allowed the penetration of drug into retina. Furthermore, the use of Tobra-SLN resulted in both higher intraphagocytic antibiotic concentrations in polymorphonuclear granulocytes and greater bactericidal activity against intracellular Pseudomonas aeruginosa

  15. The pharmacokinetics of the interstitial space in humans

    OpenAIRE

    Levitt, David G

    2003-01-01

    Background The pharmacokinetics of extracellular solutes is determined by the blood-tissue exchange kinetics and the volume of distribution in the interstitial space in the different organs. This information can be used to develop a general physiologically based pharmacokinetic (PBPK) model applicable to most extracellular solutes. Methods The human pharmacokinetic literature was surveyed to tabulate the steady state and equilibrium volume of distribution of the solutes mannitol, EDTA, morphi...

  16. Enhancement of curcumin oral absorption and pharmacokinetics of curcuminoids and curcumin metabolites in mice

    Science.gov (United States)

    Zhongfa, Liu; Chiu, Ming; Wang, Jiang; Chen, Wei; Yen, Winston; Fan-Havard, Patty; Yee, Lisa D.; Chan, Kenneth K.

    2012-01-01

    Purpose Curcumin has shown a variety of biological activity for various human diseases including cancer in preclinical setting. Its poor oral bioavailability poses significant pharmacological barriers to its clinical application. Here, we established a practical nano-emulsion curcumin (NEC) containing up to 20% curcumin (w/w) and conducted the pharmacokinetics of curcuminoids and curcumin metabolites in mice. Methods This high loading NEC was formulated based on the high solubility of curcumin in polyethylene glycols (PEGs) and the synergistic enhancement of curcumin absorption by PEGs and Cremophor EL. The pharmacokinetics of curcuminoids and curcumin metabolites was characterized in mice using a LC–MS/MS method, and the pharmacokinetic parameters were determined using WinNonlin computer software. Results A tenfold increase in the AUC0→24h and more than 40-fold increase in the Cmax in mice were observed after an oral dose of NEC compared with suspension curcumin in 1% methylcellulose. The plasma pharmacokinetics of its two natural congeners, demethoxycurcumin and bisdemethoxycurcumin, and three metabolites, tetrahydrocurcumin (THC), curcumin-O-glucuronide, and curcumin-O-sulfate, was characterized for the first time in mice after an oral dose of NEC. Conclusion This oral absorption enhanced NEC may provide a practical formulation to conduct the correlative study of the PK of curcuminoids and their pharmacodynamics, e.g., hypomethylation activity in vivo. PMID:21968952

  17. [Research progress of pharmacokinetics and pharmacodynamics of total glucosides of peony in hepatoprotective effects].

    Science.gov (United States)

    Zuo, Zhi-Yan; Zhan, Shu-Yu; Huang, Xuan; Ding, Bao-Yue; Liu, Yu-Qian; Ruan, Yu-Er; Jiang, Ning-Hua

    2017-10-01

    Total glucosides of peony (TGP), containing the effective components of paeoniflorin (Pae), albiflorin (Alb) and so on, are effective parts of Radix Paeoniae Alba. And it possesses extensive pharmacological actions, one of which is hepatoprotective effect. In recent years, abundant of pharmacokinetics and pharmacodynamics research of TGP in hepatoprotective effects have been performed. However, the relative medicine of TGP in hepatoprotective effect has not been developed for clinical application. In order to provide reference for the development and rational clinical application of TGP, the research progresses of pharmacokinetics and pharmacodynamics of TGP in hepatoprotective effect were summarized in this paper. Pharmacokinetics research has clarified the process of absorption, distribution, metabolism and excretion of TGP in vivo, and liver injury disease can significantly influence its metabolic processes. Pharmacodynamics studies suggested that TGP can protect against acute liver injury, non-alcoholic fatty liver diseases (NAFLD), chronic liver fibrosis and liver cancer. However, the action mechanism and in vivo process about hepatoprotective effects of TGP have not been clearly revealed. How liver injury influences the metabolism of TGP and its integrated regulation through multiple targets need to be further studied. The combined pharmacokinetics and pharmacodynamics studies should be performed in favour of medicine development and clinical application of TGP in hepatoprotective effects. Copyright© by the Chinese Pharmaceutical Association.

  18. Pharmacokinetics of hederacoside C, an active ingredient in AG NPP709, in rats.

    Science.gov (United States)

    Kim, Ju Myung; Yoon, Ji Na; Jung, Ji Won; Choi, Hye Duck; Shin, Young June; Han, Chang Kyun; Lee, Hye Suk; Kang, Hee Eun

    2013-11-01

    1. Hederacoside C (HDC) is one of the active ingredients in Hedera helix leaf extract (Ivy Ex.) and AG NPP709, a new botanical drug to treat acute respiratory infection and chronic inflammatory bronchitis. However, information regarding its pharmacokinetic properties remains limited. 2. Here, we report the pharmacokinetics of HDC in rats after intravenous administration of HDC (3, 12.5, and 25 mg/kg) and after oral administration of HDC, Ivy Ex., and AG NPP709 (equivalent to 12.5, 25, and 50 mg/kg HDC). 3. Linear pharmacokinetics of HDC were identified upon its intravenous administration at doses of 3-25 mg/kg. Intravenous administration of HDC results in relatively slow clearance (1.46-2.08 mL/min/kg) and a small volume of distribution at steady state (138-222 mL/kg), while oral administration results in a low absolute oral bioavailability (F) of 0.118-0.250%. The extremely low F of HDC may be due to poor absorption of HDC from the gastrointestinal (GI) tract and/or its decomposition therein. 4. The oral pharmacokinetics of HDC did not differ significantly among pure HDC, Ivy Ex., and AG NPP709.

  19. Preparation and ocular pharmacokinetics of ganciclovir liposomes

    OpenAIRE

    Shen, Yan; Tu, Jiasheng

    2007-01-01

    Ophthalmic liposomes of ganciclovir (GCV) were prepared by the reverse phase evaporation method, and their ocular pharmacokinetics in albino rabbits were compared with those obtained after dosing with GCV solution. The in vitro transcorneal permeability of GCV liposomes was found to be 3.9-fold higher than that of the solution. After in vivo instillation in albino rabbits, no difference was found in the precorneal elimination rate of GCV from liposome vs solution dosing. The aqueous humor con...

  20. Perioperative pharmacokinetics of methadone in adolescents.

    Science.gov (United States)

    Sharma, Anshuman; Tallchief, Danielle; Blood, Jane; Kim, Thomas; London, Amy; Kharasch, Evan D

    2011-12-01

    Methadone is frequently administered to adults experiencing anesthesia and receiving pain treatment. Methadone pharmacokinetics in adults are well characterized, including the perioperative period. Methadone is also used in children. There is, however, no information on methadone pharmacokinetics in children of any age. The purpose of this investigation was to determine the pharmacokinetics of intravenous methadone in children undergoing surgery. Perioperative opioid-sparing effects were also assessed. Eligible subjects were children 5-18 yr undergoing general anesthesia and surgery, with an anticipated postoperative inpatient stay exceeding 3 days. Three groups of 10 to 11 patients each received intravenous methadone hydrochloride after anesthetic induction in ascending dose groups of 0.1, 0.2, and 0.3 mg/kg (up to 20 mg). Anesthetic care was not otherwise changed. Venous blood was obtained for 4 days, for stereoselective determination of methadone and metabolites. Pain assessments were made each morning. Daily and total opioid consumption was determined. Perioperative opioid consumption and pain was determined in a second cohort, which was matched to age, sex, race, ethnicity, surgical procedure, and length of stay, but not receiving methadone. The final methadone study cohort was 31 adolescents (14 ± 2 yr, range 10-18) undergoing major spine surgery for a diagnosis of scoliosis. Methadone pharmacokinetics were linear over the dose range 0.1-0.3 mg/kg. Disposition was stereoselective. Methadone administration did not dose-dependently affect postoperative pain scores, and did not dose-dependently decrease daily or total postoperative opioid consumption in spinal fusion patients. Methadone enantiomer disposition in adolescents undergoing surgery was similar to that in healthy adults.

  1. Impact of the CYP2C8 *3 polymorphism on the drug-drug interaction between gemfibrozil and pioglitazone.

    Science.gov (United States)

    Aquilante, Christina L; Kosmiski, Lisa A; Bourne, David W A; Bushman, Lane R; Daily, Elizabeth B; Hammond, Kyle P; Hopley, Charles W; Kadam, Rajendra S; Kanack, Alexander T; Kompella, Uday B; Le, Merry; Predhomme, Julie A; Rower, Joseph E; Sidhom, Maha S

    2013-01-01

    The objective of this study was to determine the extent to which the CYP2C8*3 allele influences pharmacokinetic variability in the drug-drug interaction between gemfibrozil (CYP2C8 inhibitor) and pioglitazone (CYP2C8 substrate). In this randomized, two phase crossover study, 30 healthy Caucasian subjects were enrolled based on CYP2C8*3 genotype (n = 15, CYP2C8*1/*1; n = 15, CYP2C8*3 carriers). Subjects received a single 15 mg dose of pioglitazone or gemfibrozil 600 mg every 12 h for 4 days with a single 15 mg dose of pioglitazone administered on the morning of day 3. A 48 h pharmacokinetic study followed each pioglitazone dose and the study phases were separated by a 14 day washout period. Gemfibrozil significantly increased mean pioglitazone AUC(0,∞) by 4.3-fold (P gemfibrozil administration was significantly influenced by CYP2C8 genotype. Specifically, CYP2C8*3 carriers had a 5.2-fold mean increase in pioglitazone AUC(0,∞) compared with a 3.3-fold mean increase in CYP2C8*1 homozygotes (P = 0.02). CYP2C8*3 is associated with decreased pioglitazone plasma exposure in vivo and significantly influences the pharmacokinetic magnitude of the gemfibrozil-pioglitazone drug-drug interaction. Additional studies are needed to evaluate the impact of CYP2C8 genetics on the pharmacokinetics of other CYP2C8-mediated drug-drug interactions. © 2012 The Authors. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

  2. Impact of the CYP2C8 *3 polymorphism on the drug–drug interaction between gemfibrozil and pioglitazone

    Science.gov (United States)

    Aquilante, Christina L; Kosmiski, Lisa A; Bourne, David W A; Bushman, Lane R; Daily, Elizabeth B; Hammond, Kyle P; Hopley, Charles W; Kadam, Rajendra S; Kanack, Alexander T; Kompella, Uday B; Le, Merry; Predhomme, Julie A; Rower, Joseph E; Sidhom, Maha S

    2013-01-01

    AIM The objective of this study was to determine the extent to which the CYP2C8*3 allele influences pharmacokinetic variability in the drug–drug interaction between gemfibrozil (CYP2C8 inhibitor) and pioglitazone (CYP2C8 substrate). METHODS In this randomized, two phase crossover study, 30 healthy Caucasian subjects were enrolled based on CYP2C8*3 genotype (n = 15, CYP2C8*1/*1; n = 15, CYP2C8*3 carriers). Subjects received a single 15 mg dose of pioglitazone or gemfibrozil 600 mg every 12 h for 4 days with a single 15 mg dose of pioglitazone administered on the morning of day 3. A 48 h pharmacokinetic study followed each pioglitazone dose and the study phases were separated by a 14 day washout period. RESULTS Gemfibrozil significantly increased mean pioglitazone AUC(0,∞) by 4.3-fold (P gemfibrozil administration was significantly influenced by CYP2C8 genotype. Specifically, CYP2C8*3 carriers had a 5.2-fold mean increase in pioglitazone AUC(0,∞) compared with a 3.3-fold mean increase in CYP2C8*1 homozygotes (P= 0.02). CONCLUSION CYP2C8*3 is associated with decreased pioglitazone plasma exposure in vivo and significantly influences the pharmacokinetic magnitude of the gemfibrozil–pioglitazone drug-drug interaction. Additional studies are needed to evaluate the impact of CYP2C8 genetics on the pharmacokinetics of other CYP2C8-mediated drug–drug interactions. PMID:22625877

  3. Enantioselective pharmacokinetics of sibutramine in rat.

    Science.gov (United States)

    Noh, Keumhan; Bae, Kyoungjin; Min, Bokyoung; Kim, Eunyoung; Kwon, Kwang-il; Jeong, Taecheon; Kang, Wonku

    2010-02-01

    Racemic sibutramine is widely used to treat obesity owing to its inhibition of serotonin and noradrenaline reuptake in synapses. Although the enantioselective effects of sibutramine and its two active desmethyl-metabolites, monodesmethylsibutramine (MDS) and didesmethylsibutramine (DDS), on anorexia and energy expenditure have been elucidated, the enantioselective pharmacokinetics of sibutramine are still unclear. Therefore, we aimed to characterize the enantioselective pharmacokinetics of sibutramine and its metabolites in plasma and urine following an intravenous and a single oral administration of sibutramine in rats. The absolute bioavailability of sibutramine was only about 7%. The pharmacologically less effective S-isomer of DDS was predominant in the plasma: the C ( max ) and the AUC ( inf ) were 28 and 30 times higher than those of the R-isomer, respectively (psibutramine metabolites MDS and DDS were present at lower concentrations, owing to their rapid biotransformation to hydroxylated and/or carbamoylglucuronized forms and their faster excretion in the urine. The present study is the first to elucidate the enantioselective pharmacokinetics of sibutramine in rats.

  4. The Gap of Self - States and Its Association to an Individual‟s Interaction and Emotional Bond to their Significant Relationships: A Correlational Study about Filipino Youth‟s Self - Discrepancy and Their Attachment Styl

    Directory of Open Access Journals (Sweden)

    Mae R. Galing

    2017-05-01

    Full Text Available A youth is expected to experience difficulties due to the opposing desire to be free while still remaining dependent to family and other significant individuals in their lives. Filipino youth are known as being family - oriented and being submissive which is one of the factors that pounds the importance of what people around them utters. Thus, creating a gap or discrepancy between what they truly want and what other people expect them to do. When these internal battles began, significant external aspects such as social interaction can be compromised. These occurrences can be elucidated by using the two frameworks Self - Discrepancy Theory and Attachment Style. In this study, correlational research design and survey method were employed to 384 Filipino Youth from Makati whom are selected through convenience sampling. Results of the study showed that the respondents have positive image of themselves. Also, a big majority of the respondents were discerned to have high discrepancies between their self - states. In this study, it was also seen that the respondents were dismissive and were characterized to be independent, self - reliant, and gave low importance to relationships. Finally, findings of this study revealed a weak positive correlation between secure attachment s tyle towards the self - discrepancy of the respondents while weak negative correlation was found between the rest of the attachment styles towards the discrepancy among their self - states. With this, the researchers recommended stabilizing internal discrepanc ies and strengthening significant relationships as the two were seen as big factors in respondents’ social interaction and self - esteem.

  5. Clinical pharmacokinetic study for the effect of glimepiride matrix tablets developed by quality by design concept.

    Science.gov (United States)

    Ahmed, Tarek A; Suhail, Mohammad A A; Hosny, Khaled M; Abd-Allah, Fathy I

    2018-01-01

    Implementation of a new pharmaceutical technique to improve aqueous solubility and thus dissolution, enhancement of drug permeation, and finally formulation of a controlled release tablet loaded with glimepiride (GLMP). Improve GLMP bioavailability and pharmacokinetics in type II diabetic patients. Different polymers were used to enhance aqueous GLMP solubility of which a saturated polymeric drug solution was prepared and physically adsorbed onto silica. An experimental design was employed to optimize the formulation parameters affecting the preparation of GLMP matrix tablets. A compatibility study was conducted to study components interactions. Scanning electron microscope (SEM) was performed before and after the tablets were placed in the dissolution medium. An in vivo study in human volunteers was performed with the optimized GLMP tablets, which were compared to pure and marketed drug products. Enhancement of GLMP aqueous solubility, using the polymeric drug solution technique, by more than 6-7 times when compared with the binary system. All the studied formulation factors significantly affected the studied variables. No significant interaction was detected among components. SEM illustrated the surface and inner tablet structure, and confirmed the drug release which was attributed to diffusion mechanism. The volunteer group administered the optimized GLMP tablet exhibited higher drug plasma concentration (147.4 ng/mL), longer time to reach maximum plasma concentration (4 h) and longer t 1/2 (7.236 h) compared to other groups. Matrix tablet loaded with a physically modified drug form could represent a key solution for drugs with inconsistent dissolution and absorption profiles.

  6. The Influence of CYP2D6 Phenotype on the Pharmacokinetic Profile of Atomoxetine in Caucasian Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Todor Ioana

    2017-06-01

    Full Text Available Objective: To analyze a potential phenotypic variation within the studied group based on the pharmacokinetic profile of atomoxetine and its active metabolite, and to further investigate the impact of CYP2D6 phenotype on atomoxetine pharmacokinetics. Methods: The study was conducted as an open-label, non-randomized clinical trial which included 43 Caucasian healthy volunteers. Each subject received a single oral dose of atomoxetine 25 mg. Subsequently, atomoxetine and 4-hydroxyatomoxetine-O-glucuronide (glucuronidated active metabolite plasma concentrations were determined and a noncompartmental method was used to calculate the pharmacokinetic parameters of both compounds. Further on, the CYP2D6 metabolic phenotype was assessed using the area under the curve (AUC metabolic ratio (atomoxetine/ 4-hydroxyatomoxetine-O-glucuronide and specific statistical tests (Lilliefors (Kolgomorov-Smirnov and Anderson-Darling test. The phenotypic differences in atomoxetine disposition were identified based on the pharmacokinetic profile of the parent drug and its metabolite. Results: The statistical analysis revealed that the AUC metabolic ratio data set did not follow a normal distribution. As a result, two different phenotypes were identified, respectively the poor metabolizer (PM group which included 3 individuals and the extensive metabolizer (EM group which comprised the remaining 40 subjects. Also, it was demonstrated that the metabolic phenotype significantly influenced atomoxetine pharmacokinetics, as PMs presented a 4.5-fold higher exposure to the parent drug and a 3.2-fold lower exposure to its metabolite in comparison to EMs. Conclusions: The pharmacokinetic and statistical analysis emphasized the existence of 2 metabolic phenotypes: EMs and PMs. Furthermore, it was proved that the interphenotype variability had a marked influence on atomoxetine pharmacokinetic profile.

  7. Population Pharmacokinetics of Morphine and Morphine-6-Glucuronide following Rectal Administration

    DEFF Research Database (Denmark)

    Brokjær, Anne; Kreilgaard, Mads; Olesen, Anne Estrup

    2015-01-01

    INTRODUCTION: To safely and effectively administer morphine as liquid formulation via the rectal route, a thorough understanding of the pharmacokinetics is warranted. The aims were: 1) to develop a population pharmacokinetic model of liquid rectal morphine and morphine-6-glucoronide (M6G), 2...... cm from the anal verge. A 2 mg morphine hydrochloride dose was administered intravenously as reference. Blood samples were drawn at baseline and at nine time points post dosing. Serum was obtained by centrifugation and assayed for contents of morphine and M6G with a validated high performance liquid...... chromatographic method. Modelling was performed using NONMEM 7.2 and the first order conditional estimation method with interaction. RESULTS: A two compartment distribution model with one absorption transit compartment for rectal administration and systemic clearance from the central compartment best described...

  8. Effect of gemfibrozil and rifampicin on the pharmacokinetics of selexipag and its active metabolite in healthy subjects.

    Science.gov (United States)

    Bruderer, Shirin; Petersen-Sylla, Marc; Boehler, Margaux; Remeňová, Tatiana; Halabi, Atef; Dingemanse, Jasper

    2017-12-01

    Based on in vitro data, there is evidence to suggest that cytochrome P450 (CYP) 2C8 is involved in the metabolism of selexipag and its active metabolite, ACT-333679. The present study evaluated the possible pharmacokinetic interactions of selexipag with gemfibrozil, a strong CYP2C8 inhibitor, and rifampicin, an inducer of CYP2C8. The study consisted of two independent parts, each conducted according to an open-label, randomized, crossover design. The pharmacokinetics and safety of selexipag and ACT-333679 were studied following single-dose administration either alone or in the presence of multiple-dose gemfibrozil (part I) or rifampicin (part II) in healthy male subjects. Gemfibrozil had comparatively small effects on selexipag (less than 2-fold difference in any pharmacokinetic variable) but, with respect to ACT-333679, increased the maximum plasma concentration (C max ) 3.6-fold [90% confidence interval (CI) 3.1, 4.3] and the area under the plasma concentration-time curve from zero to infinity (AUC 0-∞ ) 11.1-fold (90% CI 9.2, 13.4). The marked increased exposure to ACT-333679, which mediates the majority of the pharmacological activity of selexipag, was accompanied by significantly more adverse events such as headache, nausea and vomiting. Coadministration of rifampicin increased the C max of selexipag 1.8-fold (90% CI 1.4, 2.2) and its AUC0 -∞ 1.3-fold (90% CI 1.1, 1.4); its effects on ACT-333679 were to increase its C max 1.3-fold (90% CI 1.1, 1.6), shorten its half-life by 63% and reduce its AUC0 -∞ by half (90% CI 0.45, 0.59). Concomitant administration of selexipag and strong inhibitors of CYP2C8 must be avoided, whereas when coadministered with inducers of CYP2C8, dose adjustments of selexipag should be envisaged. © 2017 The British Pharmacological Society.

  9. Significant interactions between maternal PAH exposure and haplotypes in candidate genes on B[a]P-DNA adducts in a NYC cohort of non-smoking African-American and Dominican mothers and newborns

    Science.gov (United States)

    Tang, Deliang

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAH) are a class of chemicals common in the environment. Certain PAH are carcinogenic, although the degree to which genetic variation influences susceptibility to carcinogenic PAH remains unclear. Also unknown is the influence of genetic variation on the procarcinogenic effect of in utero exposures to PAH. Benzo[a]pyrene (B[a]P) is a well-studied PAH that is classified as a probable human carcinogen. Within our New York City-based cohort, we explored interactions between maternal exposure to airborne PAH during pregnancy and maternal and newborn haplotypes (and in one case, a single-nucleotide polymorphism) in key B[a]P metabolism genes on B[a]P-DNA adducts in paired cord blood samples. The study subjects included non-smoking African-American (n = 132) and Dominican (n = 235) women with available data on maternal PAH exposure, paired cord adducts and genetic data who resided in the Washington Heights, Central Harlem and South Bronx neighborhoods of New York City. We selected seven maternal and newborn genes related to B[a]P metabolism, detoxification and repair for our analyses: CYP1A1, CYP1A2, CYP1B1, GSTM3, GSTT2, NQO1 and XRCC1. We found significant interactions between maternal PAH exposure and haplotype on cord B[a]P-DNA adducts in the following genes: maternal CYP1B1, XRCC1 and GSTM3, and newborn CYP1A2 and XRCC1 in African-Americans; and maternal XRCC1 and newborn NQO1 in Dominicans. These novel findings highlight differences in maternal and newborn genetic contributions to B[a]P-DNA adduct formation, as well as ethnic differences in gene–environment interactions, and have the potential to identify at-risk subpopulations who are susceptible to the carcinogenic potential of B[a]P. PMID:24177223

  10. Significant inhibitory impact of dibenzyl trisulfide and extracts of Petiveria alliacea on the activities of major drug-metabolizing enzymes in vitro: An assessment of the potential for medicinal plant-drug interactions.

    Science.gov (United States)

    Murray, J; Picking, D; Lamm, A; McKenzie, J; Hartley, S; Watson, C; Williams, L; Lowe, H; Delgoda, R

    2016-06-01

    Dibenzyl trisulfide (DTS) is the major active ingredient expressed in Petiveria alliacea L., a shrub widely used for a range of conditions, such as, arthritis, asthma and cancer. Given its use alone and concomitantly with prescription medicines, we undertook to investigate its impact on the activities of important drug metabolizing enzymes, the cytochromes P450 (CYP), a key family of enzymes involved in many adverse drug reactions. DTS and seven standardized extracts from the plant were assessed for their impact on the activities of CYPs 1A2, 2C19, 2C9, 2D6 and 3A4 on a fluorometric assay. DTS revealed significant impact against the activities of CYPs 1A2, 2C19 and 3A4 with IC50 values of 1.9, 4.0 and 3.2μM, respectively, which are equivalent to known standard inhibitors of these enzymes (furafylline, and tranylcypromine), and the most potent interaction with CYP1A2 displayed irreversible enzyme kinetics. The root extract, drawn with 96% ethanol (containing 2.4% DTS), displayed IC50 values of 5.6, 3.9 and 4.2μg/mL respectively, against the same isoforms, CYPs 1A2, 2C19 and 3A4. These investigations identify DTS as a valuable CYP inhibitor and P. alliacea as a candidate plant worthy of clinical trials to confirm the conclusions that extracts yielding high DTS may lead to clinically relevant drug interactions, whilst extracts yielding low levels of DTS, such as aqueous extracts, are unlikely to cause adverse herb-drug interactions. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Development of a physiologically based pharmacokinetic model for inhalation of jet fuels in the rat.

    Science.gov (United States)

    Martin, Sheppard A; Campbell, Jerry L; Tremblay, Raphael T; Fisher, Jeffrey W

    2012-01-01

    The pharmacokinetic behavior of the majority of jet fuel constituents has not been previously described in the framework of a physiologically based pharmacokinetic (PBPK) model for inhalation exposure. Toxic effects have been reported in multiple organ systems, though exposure methods varied across studies, utilizing either vaporized or aerosolized fuels. The purpose of this work was to assess the pharmacokinetics of aerosolized and vaporized fuels, and develop a PBPK model capable of describing both types of exposures. To support model development, n-tetradecane and n-octane exposures were conducted at 89 mg/m(3) aerosol+vapor and 1000-5000 ppm vapor, respectively. Exposures to JP-8 and S-8 were conducted at ~900-1000 mg/m(3), and ~200 mg/m(3) to a 50:50 blend of both fuels. Sub-models were developed to assess the behavior of representative constituents and grouped unquantified constituents, termed "lumps", accounting for the remaining fuel mass. The sub-models were combined into the first PBPK model for petroleum and synthetic jet fuels. Inhalation of hydrocarbon vapors was described with simple gas-exchange assumptions for uptake and exhalation. For aerosol droplets systemic uptake occurred in the thoracic region. Visceral tissues were described using perfusion and diffusion-limited equations. The model described kinetics at multiple fuel concentrations, utilizing a chemical "lumping" strategy to estimate parameters for fractions of speciated and unspeciated hydrocarbons and gauge metabolic interactions. The model more accurately simulated aromatic and lower molecular weight (MW) n-alkanes than some higher MW chemicals. Metabolic interactions were more pronounced at high (~2700-1000 mg/m(3)) concentrations. This research represents the most detailed assessment of fuel pharmacokinetics to date.

  12. Predicting transporter-mediated drug interactions: Commentary on: "Pharmacokinetic evaluation of a drug transporter cocktail consisting of digoxin, furosemide, metformin and rosuvastatin" and "Validation of a microdose probe drug cocktail for clinical drug interaction assessments for drug transporters and CYP3A".

    Science.gov (United States)

    Zhang, L; Sparreboom, A

    2017-04-01

    Transporters, expressed in various tissues, govern the absorption, distribution, metabolism, and excretion of drugs, and consequently their inherent safety and efficacy profiles. Drugs may interact with a transporter as a substrate and/or an inhibitor. Understanding transporter-mediated drug-drug interactions (DDIs), in addition to enzyme-mediated DDIs, is an integral part of risk assessment in drug development and regulatory review because the concomitant use of more than one medication in patients is common. © 2016 ASCPT.

  13. Pharmacokinetic-pharmacodynamic modeling of diclofenac in normal and Freund's complete adjuvant-induced arthritic rats

    Science.gov (United States)

    Zhang, Jing; Li, Pei; Guo, Hai-fang; Liu, Li; Liu, Xiao-dong

    2012-01-01

    Aim: To characterize pharmacokinetic-pharmacodynamic modeling of diclofenac in Freund's complete adjuvant (FCA)-induced arthritic rats using prostaglandin E2 (PGE2) as a biomarker. Methods: The pharmacokinetics of diclofenac was investigated using 20-day-old arthritic rats. PGE2 level in the rats was measured using an enzyme immunoassay. A pharmacokinetic-pharmacodynamic (PK-PD) model was developed to illustrate the relationship between the plasma concentration of diclofenac and the inhibition of PGE2 production. The inhibition of diclofenac on lipopolysaccharide (LPS)-induced PGE2 production in blood cells was investigated in vitro. Results: Similar pharmacokinetic behavior of diclofenac was found both in normal and FCA-induced arthritic rats. Diclofenac significantly decreased the plasma levels of PGE2 in both normal and arthritic rats. The inhibitory effect on PGE2 levels in the plasma was in proportion to the plasma concentration of diclofenac. No delay in the onset of inhibition was observed, suggesting that the effect compartment was located in the central compartment. An inhibitory effect sigmoid Imax model was selected to characterize the relationship between the plasma concentration of diclofenac and the inhibition of PGE2 production in vivo. The Imax model was also used to illustrate the inhibition of diclofenac on LPS-induced PGE2 production in blood cells in vitro. Conclusion: Arthritis induced by FCA does not alter the pharmacokinetic behaviors of diclofenac in rats, but the pharmacodynamics of diclofenac is slightly affected. A PK-PD model characterizing an inhibitory effect sigmoid Imax can be used to fit the relationship between the plasma PGE2 and diclofenac levels in both normal rats and FCA-induced arthritic rats. PMID:22842736

  14. The sheep as a model of preclinical safety and pharmacokinetic evaluations of candidate microbicides.

    Science.gov (United States)

    Holt, Jonathon D S; Cameron, David; Dias, Nicola; Holding, Jeremy; Muntendam, Alex; Oostebring, Freddy; Dreier, Peter; Rohan, Lisa; Nuttall, Jeremy

    2015-07-01

    When developing novel microbicide products for the prevention of HIV infection, the preclinical safety program must evaluate not only the active pharmaceutical ingredient but also the product itself. To that end, we applied several relatively standard toxicology study methodologies to female sheep, incorporating an assessment of the pharmacokinetics, safety, tolerability, and local toxicity of a dapivirine-containing human vaginal ring formulation (Dapivirine Vaginal Ring-004). We performed a 3-month general toxicology study, a preliminary pharmacokinetic study using drug-loaded vaginal gel, and a detailed assessment of the kinetics of dapivirine delivery to plasma, vaginal, and rectal fluid and rectal, vaginal, and cervical tissue over 28 days of exposure and 3 and 7 days after removal of the ring. The findings of the general toxicology study supported the existing data from both preclinical and clinical studies in that there were no signs of toxicity related to dapivirine. In addition, the presence of the physical dapivirine ring did not alter local or systemic toxicity or the pharmacokinetics of dapivirine. Pharmacokinetic studies indicated that the dapivirine ring produced significant vaginal tissue levels of dapivirine. However, no dapivirine was detected in cervical tissue samples using the methods described here. Plasma and vaginal fluid levels were lower than those in previous clinical studies, while there were detectable dapivirine levels in the rectal tissue and fluid. All tissue and fluid levels tailed off rapidly to undetectable levels following removal of the ring. The sheep represents a very useful model for the assessment of the safety and pharmacokinetics of microbicide drug delivery devices, such as the vaginal ring. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  15. Effect of co-medication on the pharmacokinetic parameters of phenobarbital in asphyxiated newborns.

    Science.gov (United States)

    Šíma, M; Pokorná, P; Hronová, K; Slanař, O

    2015-01-01

    Phenobarbital is an anticonvulsive drug widely used in newborns with hypoxic-ischemic encephalopathy. The objective of our study was to describe possible effect of frequently co-administered medications (dopamine, dobutamine, norepinephrine, furosemide, phenytoin, and analgesics) on the phenobarbital pharmacokinetics in full term newborns with hypoxic-ischemic encephalopathy. Phenobarbital pharmacokinetic parameters (standardized intravenous loading dose was 10-20 mg/kg, maintenance dose 2-6 mg/kg/day) were computed using non-compartmental analysis. Co-medication was evaluated throughout the whole treatment period up to 5 days. Volume of distribution, clearance, and half-life median values (95 % CI) for phenobarbital in the whole study population (n=37) were 0.48 (0.41-0.56) l/kg, 0.0034 (0.0028-0.0040) l/h/kg, and 93.7 (88.1-99.2) h, respectively. Phenobarbital pharmacokinetic parameters were not significantly affected by vasoactive drugs (dopamine, dobutamine, and norepinephrine), furosemide, phenytoin, or analgesics. Furthermore, no dose-dependent alteration of phenobarbital pharmacokinetic parameters was noted for vasoactive medication at doses equivalent to cumulative vasoactive-inotropic score (area under the curve in a plot of vasoactive-inotropic score against time) 143.2-8473.6, furosemide at cumulative doses of 0.2-42.9 mg/kg, or phenytoin at cumulative doses of 10.3-46.2 mg/kg. Phenobarbital pharmacokinetics was not affected by investigated co-administered drugs used in newborns with hypoxic-ischemic encephalopathy in real clinical settings.

  16. Clinical Pharmacokinetics of Sacubitril/Valsartan (LCZ696): A Novel Angiotensin Receptor-Neprilysin Inhibitor.

    Science.gov (United States)

    Ayalasomayajula, Surya; Langenickel, Thomas; Pal, Parasar; Boggarapu, Sreedevi; Sunkara, Gangadhar

    2017-12-01

    Sacubitril/valsartan (LCZ696) is indicated for the treatment of heart failure with reduced ejection fraction. Absorption of sacubitril/valsartan and conversion of sacubitril (prodrug) to sacubitrilat (neprilysin inhibitor) was rapid with maximum plasma concentrations of sacubitril, sacubitrilat, and valsartan (angiotensin receptor blocker) reaching within 0.5, 1.5-2.0, and 2.0-3.0 h, respectively. With a two-fold increase in dose, an increase in the area under the plasma concentration-time curve was proportional for sacubitril, ~1.9-fold for sacubitrilat, and ~1.7-fold for valsartan in healthy subjects. Following multiple twice-daily administration, steady-state maximum plasma concentration was reached within 3 days, showing no accumulation for sacubitril and valsartan, while ~1.6-fold accumulation for sacubitrilat. Sacubitril is eliminated predominantly as sacubitrilat through the kidney; valsartan is eliminated mainly by biliary route. Drug-drug interactions of sacubitril/valsartan were evaluated with medications commonly used in patients with heart failure including furosemide, warfarin, digoxin, carvedilol, levonorgestrel/ethinyl estradiol combination, amlodipine, omeprazole, hydrochlorothiazide, intravenous nitrates, metformin, statins, and sildenafil. Co-administration with sacubitril/valsartan increased the maximum plasma concentration (~2.0-fold) and area under the plasma concentration-time curve (1.3-fold) of atorvastatin; however, it did not affect the pharmacokinetics of simvastatin. Age, sex, or ethnicity did not affect the pharmacokinetics of sacubitril/valsartan. In patients with heart failure vs. healthy subjects, area under the plasma concentration-time curves of sacubitril, sacubitrilat, and valsartan were higher by approximately 1.6-, 2.1-, and 2.3-fold, respectively. Renal impairment had no significant impact on sacubitril and valsartan area under the plasma concentration-time curves, while the area under the plasma concentration-time curve of

  17. Effect of Terbinafine on Theophylline Pharmacokinetics in Healthy Volunteers

    Science.gov (United States)

    Trépanier, Eric F.; Nafziger, Anne N.; Amsden, Guy W.

    1998-01-01

    Twelve healthy volunteers were enrolled in an open-label, randomized, crossover study. Subjects received single doses of theophylline (5 mg/kg) with and without multiple-dose terbinafine, and 11 blood samples were collected over 24 h. The study phases were separated by a 4-week washout period. Theophylline serum data were modeled via noncompartmental analysis. When the control phase (i.e., no terbinafine) was compared to the treatment phase (terbinafine), theophylline exposure (the area under the serum concentration-time curve from time zero to infinity) increased by 16% (P = 0.03), oral clearance decreased by 14% (P = 0.04), and half-life increased by 24% (P = 0.002). No significant changes in other theophylline pharmacokinetic parameters were evident. PMID:9517954

  18. [Pharmacokinetic alterations in pregnancy and use of therapeutic drug monitoring].

    Science.gov (United States)

    Panchaud, Alice; Weisskopf, Etienne; Winterfeld, Ursula; Baud, David; Guidi, Monia; Eap, Chin B; Csajka, Chantal; Widmer, Nicolas

    2014-01-01

    Following the thalidomide tragedy, pharmacological research in pregnant women focused primarily on drug safety for the unborn child and remains only limited regarding the efficacy and safety of treatment for the mother. Significant physiological changes during pregnancy may yet affect the pharmacokinetics of drugs and thus compromise its efficacy and/or safety. Therapeutic drug monitoring (TDM) would maximize the potential effectiveness of treatments, while minimizing the potential risk of toxicity for the mother and the fetus. At present, because of the lack of concentration-response relationship studies in pregnant women, TDM can rely only on individual assessment (based on an effective concentration before pregnancy) and remains reserved only to unexpected situations such as signs of toxicity or unexplained inefficiency. © 2014 Société Française de Pharmacologie et de Thérapeutique.

  19. Pharmacokinetics and pharmacodynamics of the injectable formulation of methadone hydrochloride and methadone in lipid nanocarriers administered orally to horses.

    Science.gov (United States)

    Crosignani, N; Luna, S P; Dalla Costa, T; Pimenta, E L; Detoni, C B; Guterres, S S; Puoli Filho, J N; Pantoja, J C; Pigatto, M C

    2017-08-01

    We investigated the thermal, electrical and mechanical antinociceptive and physiological effects (heart rate, respiratory rate, arterial blood pressure, head height and abdominal auscultation score), and pharmacokinetics, of 0.5 mg/kg of the injectable formulation (ORAL) or nanoparticulated methadone (NANO) given orally, in six adult mares, using a crossover, blind and prospective design. Repeated-measure models were used to compare parametric data between and within treatments, followed by Tukey's test. Nonparametric data were analysed with Wilcoxon signed-rank, adjusted by Bonferroni tests. Blood samples were also collected up to 6 h after dosing for plasma drug quantification by LC-MS/MS. Methadone pharmacokinetic parameters were determined by noncompartmental and compartmental approaches. There were no differences in pharmacodynamic parameters. No statistical differences were observed in the pharmacokinetic parameters from noncompartmental analysis for both groups, except a significant decrease in peak plasma concentration, increase in apparent volume of distribution per fraction absorbed (Vd ss /F) and increased mean residence time (MRT) for NANO. One-compartment open model with first order elimination best described the pharmacokinetic profiles for both groups. Neither ORAL nor NANO administered orally to horses produced antinociception. The nanoencapsulated formulation of methadone given orally to horses did not improve methadone pharmacokinetic parameters or increased systemic body exposure to methadone. © 2017 John Wiley & Sons Ltd.

  20. Alterations in Pharmacokinetics of Gemcitabine and Erlotinib by Concurrent Administration of Hyangsayukgunja-Tang, a Gastroprotective Herbal Medicine.

    Science.gov (United States)

    Kim, Tae Hwan; Shin, Soyoung; Kim, Sarah; Bulitta, Jürgen B; Weon, Kwon-Yeon; Joo, Sang Hoon; Ma, Eunsook; Yoo, Sun Dong; Park, Gi-Young; Kwon, Dong Rak; Jeong, Seok Won; Lee, Da Young; Shin, Beom Soo

    2017-09-10

    Gemcitabine and erlotinib are the chemotherapeutic agents used in the treatment of various cancers and their combination is being accepted as a first-line treatment of advanced pancreatic cancer. Hyangsayukgunja-tang (HYT) is a traditional oriental medicine used in various digestive disorders and potentially helpful to treat gastrointestinal adverse effects related to chemotherapy. The present study was aimed to evaluate the effect of HYT on the pharmacokinetics of gemcitabine and erlotinib given simultaneously in rats. Rats were pretreated with HYT at an oral dose of 1200 mg/kg/day once daily for a single day or 14 consecutive days. Immediately after pretreatment with HYT, gemcitabine and erlotinib were administered by intravenous injection (10 mg/kg) and oral administration (20 mg/kg), respectively. The effects of HYT on pharmacokinetics of the two drugs were estimated by non-compartmental analysis and pharmacokinetic modeling. The pharmacokinetics of gemcitabine and erlotinib were not altered by single dose HYT pretreatment. However, the plasma levels of OSI-420 and OSI-413, active metabolites of erlotinib, were significantly decreased in the multiple dose HYT pretreatment group. The pharmacokinetic model estimated increased systemic clearances of OSI-420 and OSI-413 by multiple doses of HYT. These data suggest that HYT may affect the elimination of OSI-420 and OSI-413.

  1. Pharmacokinetics of bisphenol A in neonatal and adult rhesus monkeys

    International Nuclear Information System (INIS)

    Doerge, Daniel R.; Twaddle, Nathan C.; Woodling, Kellie A.; Fisher, Jeffrey W.

    2010-01-01

    Bisphenol A (BPA) is a high-production volume industrial chemical used in the manufacture of polycarbonate plastic products and epoxy resin-based food can liners. The presence of BPA in urine of > 90% of Americans aged 6-60 is controversial because of the potential for endocrine disruption, particularly during perinatal development, as suggested by in vitro, experimental animal, and epidemiological studies. The current study used LC/MS/MS to measure serum pharmacokinetics of aglycone (active) and conjugated (inactive) BPA in adult and neonatal rhesus monkeys by oral (PND 5, 35, 70) and intravenous injection (PND 77) routes using d6-BPA to avoid sample contamination. The concentration-time profiles observed in adult monkeys following oral administration of 100 μg/kg bw were remarkably similar to those previously reported in human volunteers given a similar dose; moreover, minimal pharmacokinetic differences were observed between neonatal and adult monkeys for the receptor-active aglycone form of BPA. Circulating concentrations of BPA aglycone were quite low following oral administration (< 1% of total), which reflects the redundancy of active UDP-glucuronosyl transferase isoforms in both gut and liver. No age-related changes were seen in internal exposure metrics for aglycone BPA in monkeys, a result clearly different from developing rats where significant inverse age-related changes, based on immaturity of Phase II metabolism and renal excretion, were recently reported. These observations imply that any toxicological effect observed in rats from early postnatal exposures to BPA could over-predict those possible in primates of the same age, based on significantly higher internal exposures and overall immaturity at birth.

  2. Comparative pharmacokinetics of minocycline in foals and adult horses.

    Science.gov (United States)

    Giguère, S; Burton, A J; Berghaus, L J; Haspel, A D

    2017-08-01

    The objective of this study was to compare the pharmacokinetics of minocycline in foals vs. adult horses. Minocycline was administered to six healthy 6- to 9-week-old foals and six adult horses at a dose of 4 mg/kg intragastrically (IG) and 2 mg/kg intravenously (i.v.) in a cross-over design. Five additional oral doses were administered at 12-h intervals in foals. A microbiologic assay was used to measure minocycline concentration in plasma, urine, synovial fluid, and cerebrospinal fluid (CSF). Liquid chromatography-tandem mass spectrometry was used to measure minocycline concentrations in pulmonary epithelial lining fluid (PELF) and bronchoalveolar (BAL) cells. After i.v. administration to foals, minocycline had a mean (±SD) elimination half-life of 8.5 ± 2.1 h, a systemic clearance of 113.3 ± 26.1 mL/h/kg, and an apparent volume of distribution of 1.24 ± 0.19 L/kg. Pharmacokinetic variables determined after i.v. administration to adult horses were not significantly different from those determined in foals. Bioavailability was significantly higher in foals (57.8 ± 19.3%) than in adult horses (32.0 ± 18.0%). Minocycline concentrations in PELF were higher than in other body fluids. Oral minocycline dosed at 4 mg/kg every 12 h might be adequate for the treatment of susceptible bacterial infections in foals. © 2016 John Wiley & Sons Ltd.

  3. Etravirine Pharmacokinetics In HIV-Infected Pregnant Women

    Directory of Open Access Journals (Sweden)

    Nikki Mulligan

    2016-08-01

    Full Text Available Background: The study goal was to describe etravirine pharmacokinetics during pregnancy and postpartum in HIV-infected women. Methods: IMPAACT P1026s and PANNA are on-going, nonrandomized, open-label, parallel-group, multi-center phase-IV prospective studies in HIV-infected pregnant women. Intensive steady-state 12 or 24 hour pharmacokinetic profiles were performed from 2nd trimester through postpartum. Etravirine was measured at two labs using validated ultra performance liquid chromatography (detection limits: 0.020 mcg/mL and 0.026 mcg/mL. Results: Fifteen women took etravirine 200 mg twice-daily dosing and one took 400 mg once-daily. Etravirine AUC0-12 was significantly higher in the 3rd trimester compared to paired postpartum data by 45% (median 8.3 mcg*hr/mL versus 5.7 mcg*hr/mL, p = 0.086. Etravirine apparent oral clearance was significantly lower in the 3rd trimester of pregnancy compared to paired postpartum data (median 24 L/h versus 35 L/h, p = 0.038. The median ratio of cord blood to maternal plasma concentration at delivery was 0.56 (range: 0.19 - 4.25 and no perinatal transmission occurred. Conclusion: Etravirine apparent oral clearance is reduced and exposure increased during the third trimester of pregnancy. Based on prior dose-ranging and safety data, no dose adjustment is necessary for maternal health but the effects of etravirine in utero are unknown. Maternal health and infant outcomes should be closely monitored until further infant safety data are available. The IMPAACT protocol P1026s and PANNA study are registered at ClinicalTrials.gov under NCT00042289 and NCT00825929.

  4. Prediction of human CNS pharmacokinetics using a physiologically-based pharmacokinetic modeling approach

    NARCIS (Netherlands)

    Yamamoto, Yumi; Valitalo, Pyry A.; Wong, Yin Cheong; Huntjens, Dymphy R.; Proost, Johannes H.; Vermeulen, An; Krauwinkel, Walter; Beukers, Margot W.; Kokki, Hannu; Kokki, Merja; Danhof, Meindert; van Hasselt, Johan G. C.; de Lange, Elizabeth C. M.

    2018-01-01

    Knowledge of drug concentration-time profiles at the central nervous system (CNS) target-site is critically important for rational development of CNS targeted drugs. Our aim was to translate a recently published comprehensive CNS physiologically-based pharmacokinetic (PBPK) model from rat to human,

  5. Population pharmacokinetics and relationship between demographic and clinical variables and pharmacokinetics of gentamicin in neonates

    NARCIS (Netherlands)

    Stolk, L M L; Degraeuwe, P L J; Nieman, F H M; de Wolf, M C; de Boer, A|info:eu-repo/dai/nl/075097346

    Population pharmacokinetic parameter estimates were calculated from 725 routine plasma gentamicin concentrations obtained in 177 neonates of 24 to 42 weeks' gestational age in their first week of life. Kel increases and V/W decreases with increasing gestational age. Almost identical results were

  6. Dermal pharmacokinetics of microemulsion formulations determined by in vivo microdialysis

    DEFF Research Database (Denmark)

    Kreilgaard, Mads

    2001-01-01

    To investigate the potential of improving dermal drug delivery of hydrophilic and lipophilic substances by formulation in microemulsion vehicles and to establish a reliable pharmacokinetic model to analyze cutaneous microdialysis data.......To investigate the potential of improving dermal drug delivery of hydrophilic and lipophilic substances by formulation in microemulsion vehicles and to establish a reliable pharmacokinetic model to analyze cutaneous microdialysis data....

  7. Pharmacokinetics of first-line tuberculosis drugs in tanzanian patients

    NARCIS (Netherlands)

    Tostmann, A.; Mtabho, C.M.; Semvua, H.H.; Boogaard, J. van den; Kibiki, G.S.; Boeree, M.J.; Aarnoutse, R.E.

    2013-01-01

    East Africa has a high tuberculosis (TB) incidence and mortality, yet there are very limited data on exposure to TB drugs in patients from this region. We therefore determined the pharmacokinetic characteristics of first-line TB drugs in Tanzanian patients using intensive pharmacokinetic sampling.

  8. Acetaminophen developmental pharmacokinetics in premature neonates and infants

    DEFF Research Database (Denmark)

    Anderson, Brian J; van Lingen, Richard A; Hansen, Tom G

    2002-01-01

    The aim of this study was to describe acetaminophen developmental pharmacokinetics in premature neonates through infancy to suggest age-appropriate dosing regimens.......The aim of this study was to describe acetaminophen developmental pharmacokinetics in premature neonates through infancy to suggest age-appropriate dosing regimens....

  9. An Allometric Model of Remifentanil Pharmacokinetics and Pharmacodynamics

    NARCIS (Netherlands)

    Eleveld, Douglas J.; Proost, Johannes H.; Vereecke, Hugo; Absalom, Anthony R.; Olofsen, Erik; Vuyk, Jaap; Struys, Michel M. R. F.

    Background: Pharmacokinetic and pharmacodynamic models are used to predict and explore drug infusion schemes and their resulting concentration profiles for clinical application. Our aim was to develop a pharmacokinetic-pharmacodynamic model for remifentanil that is accurate in patients with a wide

  10. Pharmacokinetic Variability of Drugs Used for Prophylactic Treatment of Migraine

    DEFF Research Database (Denmark)

    Tfelt-Hansen, Peer; Ågesen, Frederik Nybye; Pavbro, Agniezka

    2017-01-01

    In this review, we evaluate the variability in the pharmacokinetics of 11 drugs with established prophylactic effects in migraine to facilitate 'personalized medicine' with these drugs. PubMed was searched for 'single-dose' and 'steady-state' pharmacokinetic studies of these 11 drugs. The maximum...

  11. Effect of voriconazole on the pharmacokinetics of diclofenac.

    Science.gov (United States)

    Hynninen, Ville-Veikko; Olkkola, Klaus T; Leino, Kari; Lundgren, Stefan; Neuvonen, Pertti J; Rane, Anders; Valtonen, Mika; Laine, Kari

    2007-12-01

    The nonsteroidal anti-inflammatory drug diclofenac is extensively metabolized by cytochrome P450 (CYP) enzymes, mainly by CYP2C9. Our objective was to study the effect of voriconazole, a potent inhibitor of several CYP enzymes, on the pharmacokinetics of diclofenac. This study had a two-way, open, crossover design and included 10 healthy Caucasian male subjects. In the control phase, the subjects ingested a single 50-mg oral dose of diclofenac. In the voriconazole phase, the subjects ingested voriconazole 400 mg twice daily on the first day and 200 mg twice daily on the second day, and 50 mg diclofenac was given 1 h after the last dose of voriconazole. Plasma diclofenac concentrations were determined for up to 24 h post-dose. In the voriconazole phase, the area under the plasma concentration-time curve of diclofenac was 178% (95% CI 143-212%; P diclofenac. The renal clearance of diclofenac was decreased by 47% (95% CI -76% to -16%; P diclofenac, probably mainly by inhibition of its cytochrome P450 (CYP)-mediated metabolism. The inhibition of CYP2C9, and to some extent that of CYP3A4 and CYP2C19 enzymes during the first-pass metabolism of diclofenac seems to be involved in the interaction. The clinical importance of the interaction between voriconazole and diclofenac remains to be studied, but lower doses of diclofenac may be adequate for patients receiving voriconazole.

  12. Comparative study on the pharmacokinetics of inorganic and organic iron compounds in broiler chickens

    Directory of Open Access Journals (Sweden)

    Dimitrichka Dimitrova

    2014-03-01

    Full Text Available The pharmacokinetics of ferrous methionate and ferrous sulphate was investigated in broiler chickens after intravenous injection and crop intubation. The iron compounds were injected intravenously in v. brachialis. After 20-day “wash-out” period the ferrous methionate and ferrous sulphate were administered again by an elastic silicone tube into the crop. The serum concentrations of the iron were determined with bioanalyser. Two pharmacokinetic approaches were used – compartmental and non-compartmental analysis. After i.v. injection we found statistically significantly longer and better distribution of the iron contained in the ferrous methionate compared to the ferrous sulphate. The АUC0→∞ was statistically significantly higher in the ferrous methionate. In the alimentary tract of broiler chickens, ferrous methionate was absorbed more rapidly than ferrous sulfate. It was also distributed at a higher volume as compared to the ferrous sulfate.

  13. One should avoid retro-orbital pharmacokinetic sample collections for intranasal dosing in rats: Illustration of spurious pharmacokinetics generated for anti-migraine drugs zolmitriptan and eletriptan.

    Science.gov (United States)

    Patel, Harilal; Patel, Prakash; Modi, Nirav; Shah, Shaival; Ghoghari, Ashok; Variya, Bhavesh; Laddha, Ritu; Baradia, Dipesh; Dobaria, Nitin; Mehta, Pavak; Srinivas, Nuggehally R

    2017-08-30

    Because of the avoidance of first pass metabolic effects due to direct and rapid absorption with improved permeability, intranasal route represents a good alternative for extravascular drug administration. The aim of the study was to investigate the intranasal pharmacokinetics of two anti-migraine drugs (zolmitriptan and eletriptan), using retro-orbital sinus and jugular vein sites sampling. In a parallel study design, healthy male Sprague-Dawley (SD) rats aged between 8 and 12weeks were divided into groups (n=4 or 5/group). The animals of individual groups were dosed intranasal (~1.0mg/kg) and oral doses of 2.1mg/kg of either zolmitriptan or eletriptan. Serial blood sampling was performed from jugular vein or retro-orbital site and plasma samples were analyzed for drug concentrations using LC-MS/MS assay. Standard pharmacokinetics parameters such as T max , C max , AUC last , AUC 0-inf and T 1/2 were calculated and statistics of derived parameters was performed using unpaired t-test. After intranasal dosing, the mean pharmacokinetic parameters C max and AUC inf of zolmitriptan/eletriptan showed about 17-fold and 3-5-fold higher values for retro-orbital sampling as compared to the jugular vein sampling site. Whereas after oral administration such parameters derived for both drugs were largely comparable between the two sampling sites and statistically non-significant. In conclusion, the assessment of plasma levels after intranasal administration with retro-orbital sampling would result in spurious and misleading pharmacokinetics. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Pharmacokinetics and absolute bioavailability of phenobarbital in neonates and young infants, a population pharmacokinetic modelling approach.

    Science.gov (United States)

    Marsot, Amélie; Brevaut-Malaty, Véronique; Vialet, Renaud; Boulamery, Audrey; Bruguerolle, Bernard; Simon, Nicolas

    2014-08-01

    Phenobarbital is widely used for treatment of neonatal seizures. Its optimal use in neonates and young infants requires information regarding pharmacokinetics. The objective of this study is to characterize the absolute bioavailability of phenobarbital in neonates and young infants, a pharmacokinetic parameter which has not yet been investigated. Routine clinical pharmacokinetic data were retrospectively collected from 48 neonates and infants (weight: 0.7-10 kg; patient's postnatal age: 0-206 days; GA: 27-42 weeks) treated with phenobarbital, who were administered as intravenous or suspension by oral routes and hospitalized in a paediatric intensive care unit. Total mean dose of 4.6 mg/kg (3.1-10.6 mg/kg) per day was administered by 30-min infusion or by oral route. Pharmacokinetic analysis was performed using a nonlinear mixed-effect population model software). Data were modelled with an allometric pharmacokinetic model, using three-fourths scaling exponent for clearance (CL). The population typical mean [per cent relative standard error (%RSE)] values for CL, apparent volume of distribution (Vd ) and bioavailability (F) were 0.0054 L/H/kg (7%), 0.64 L/kg (15%) and 48.9% (22%), respectively. The interindividual variability of CL, Vd , F (%RSE) and residual variability (%RSE) was 17% (31%), 50% (27%), 39% (27%) and 7.2 mg/L (29%), respectively. The absolute bioavailability of phenobarbital in neonates and infants was estimated. The dose should be increased when switching from intravenous to oral administration. © 2013 Société Française de Pharmacologie et de Thérapeutique. Published by John Wiley & Sons Ltd.

  15. Investigating pulmonary and systemic pharmacokinetics of inhaled olodaterol in healthy volunteers using a population pharmacokinetic approach.

    Science.gov (United States)

    Borghardt, Jens Markus; Weber, Benjamin; Staab, Alexander; Kunz, Christina; Formella, Stephan; Kloft, Charlotte

    2016-03-01

    Olodaterol, a novel β2-adrenergic receptor agonist, is a long-acting, once-daily inhaled bronchodilator approved for the treatment of chronic obstructive pulmonary disease. The aim of the present study was to describe the plasma and urine pharmacokinetics of olodaterol after intravenous administration and oral inhalation in healthy volunteers by population pharmacokinetic modelling and thereby to infer its pulmonary fate. Plasma and urine data after intravenous administration (0.5-25 μg) and oral inhalation (2.5-70 μg via the Respimat® inhaler) were available from a total of 148 healthy volunteers (single and multiple dosing). A stepwise model building approach was applied, using population pharmacokinetic modelling. Systemic disposition parameters were fixed to estimates obtained from intravenous data when modelling data after inhalation. A pharmacokinetic model, including three depot compartments with associated parallel first-order absorption processes (pulmonary model) on top of a four-compartment body model (systemic disposition model), was found to describe the data the best. The dose reaching the lung (pulmonary bioavailable fraction) was estimated to be 49.4% [95% confidence interval (CI) 46.1, 52.7%] of the dose released from the device. A large proportion of the pulmonary bioavailable fraction [70.1% (95% CI 66.8, 73.3%)] was absorbed with a half-life of 21.8 h (95% CI 19.7, 24.4 h). The plasma and urine pharmacokinetics of olodaterol after intravenous administration and oral inhalation in healthy volunteers were adequately described. The key finding was that a high proportion of the pulmonary bioavailable fraction had an extended pulmonary residence time. This finding was not expected based on the physicochemical properties of olodaterol. © 2015 The British Pharmacological Society.

  16. Drug interactions between non-rifamycin antibiotics and hormonal contraception: a systematic review.

    Science.gov (United States)

    Simmons, Katharine B; Haddad, Lisa B; Nanda, Kavita; Curtis, Kathryn M

    2018-01-01

    The purpose of this study was to determine whether interactions between non-rifamycin antibiotics and hormonal contraceptives result in decreased effectiveness or increased toxicity of either therapy. We searched MEDLINE, Embase, clinicaltrials.gov, and Cochrane libraries from database inception through June 2016. We included trials, cohort, case-control, and pharmacokinetic studies in any language that addressed pregnancy rates, pharmacodynamics, or pharmacokinetic outcomes when any hormonal contraceptive and non-rifamycin antibiotic were administered together vs apart. Of 7291 original records that were identified, 29 met criteria for inclusion. Two authors independently assessed study quality and risk of bias using the United States Preventive Services Task Force evidence grading system. Findings were tabulated by drug class. Study quality ranged from good to poor and addressed only oral contraceptive pills, emergency contraception pills, and the combined vaginal ring. Two studies demonstrated no difference in pregnancy rates in women who used oral contraceptives with and without non-rifamycin antibiotics. No differences in ovulation suppression or breakthrough bleeding were observed in any study that combined hormonal contraceptives with any antibiotic. No significant decreases in any progestin pharmacokinetic parameter occurred during co-administration with any antibiotic. Ethinyl estradiol area under the curve decreased when administered with dirithromycin, but no other drug. Evidence from clinical and pharmacokinetic outcomes studies does not support the existence of drug interactions between hormonal contraception and non-rifamycin antibiotics. Data are limited by low quantity and quality for some drug classes. Most women can expect no reduction in hormonal contraceptive effect with the concurrent use of non-rifamycin antibiotics. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Interactions of Dihydromyricetin, a Flavonoid from Vine Tea (Ampelopsis grossedentata) with Gut Microbiota.

    Science.gov (United States)

    Fan, Li; Zhao, Xinyuan; Tong, Qing; Zhou, Xiya; Chen, Jing; Xiong, Wei; Fang, Jianguo; Wang, Wenqing; Shi, Chunyang

    2018-05-01

    Dihydromyricetin (DMY) is the main bioactive constituent in vine tea (Ampelopsis grossedentata), which was predominantly distributed in the gastrointestinal tract and showed poor oral bioavailability. Our aim was to systematically investigate the interactions of DMY with gut microbiota. Through the metabolism study of DMY by fecal microflora in vitro, it was found that DMY could be metabolized into three metabolites by fecal microflora via reduction and dehydroxylation pathways, and the dehydroxylation metabolite was the dominant one. Meanwhile, in order to consider the influence of gut microbiota metabolism on the pharmacokinetics of DMY, the pharmacokinetics of DMY in control and pseudo-germ-free rats were compared. It was shown that area under the curve (AUC) could only slightly increase, however, peak concentration (C max ) could significantly increase in the pseudo-germ-free rats compared with the control rats, which indicated the gut microbiota metabolism played an important role in the pharmacokinetics of DMY. In addition, the long-term influence of DMY on gut microbiota composition by using 16S rRNA pyrosequencing was further investigated. And it was found that DMY could markedly alter the richness and diversity of the gut microbiota and modulate the gut microbiota composition. The present findings will be helpful for the future development and clinical application of DMY. The gut microbiota plays an important role in the pharmacokinetics of flavonoids. As well, the long-term supplements of flavonoids could alter the gut microbiota composition in turn. The study aims to clarify the mutual interaction of DMY with gut microbiota, which may lead to new information with respect to the mechanism study and clinical application of DMY. © 2018 Institute of Food Technologists®.

  18. [Advances on pharmacokinetics of traditional Chinese medicine under disease states].

    Science.gov (United States)

    Gong, Zi-peng; Chen, Ying; Zhang, Rui-jie; Yang, Qing; Zhu, Xiao-xin

    2015-01-01

    In recent years, more and more research shows that the pharmacokinetic parameter of traditional Chinese medicine can be affected by the disease states. It's possible that drug metabolic enzymes, transporters, cell membrane permeability and the change of microbes group could be interfered with physiological and pathological changes, which enables the pharmacokinetics of traditional Chinese medicine in the body to be altered, including the process of absorption, distribution, metabolism and excretion, and then the pharmacokinetic parameters of traditional chinese medicine are altered. It's found that investigating the pharmacokinetic of traditional Chinese medicine in the pathological state is more useful than that of in normal state because the great part of traditional Chinese medicine is mainly used to treat disease. This article reflects the latest research on the pharmacokinetic of traditional Chinese medicine in the disease state such as diabete, cerebral ischemia, liver injury, inflammatory disease, nervous system disorders and fever in order to provide certain reference for clinicians designing reasonable administration dose.

  19. Low heritability in pharmacokinetics of talinolol

    DEFF Research Database (Denmark)

    Matthaei, Johannes; Tzvetkov, Mladen V; Gal, Valerie

    2016-01-01

    BACKGROUND: Efflux transporters like MDR1 and MRP2 may modulate the pharmacokinetics of about 50 % of all drugs. It is currently unknown how much of the variation in the activities of important drug membrane transporters like MDR1 or MRP2 is determined by genetic or by environmental factors...... of talinolol was predefined as the primary parameter. Heritability was analyzed by structural equation modeling and by within- and between-subject variance and talinolol clearance was correlated with polymorphisms in MDR1, MRP2, BCRP, MDR5, OATP1B1, and OCT1. RESULTS: Talinolol clearance varied approximately...

  20. Human physiologically based pharmacokinetic model for propofol

    Directory of Open Access Journals (Sweden)

    Schnider Thomas W

    2005-04-01

    Full Text Available Abstract Background Propofol is widely used for both short-term anesthesia and long-term sedation. It has unusual pharmacokinetics because of its high lipid solubility. The standard approach to describing the pharmacokinetics is by a multi-compartmental model. This paper presents the first detailed human physiologically based pharmacokinetic (PBPK model for propofol. Methods PKQuest, a freely distributed software routine http://www.pkquest.com, was used for all the calculations. The "standard human" PBPK parameters developed in previous applications is used. It is assumed that the blood and tissue binding is determined by simple partition into the tissue lipid, which is characterized by two previously determined set of parameters: 1 the value of the propofol oil/water partition coefficient; 2 the lipid fraction in the blood and tissues. The model was fit to the individual experimental data of Schnider et. al., Anesthesiology, 1998; 88:1170 in which an initial bolus dose was followed 60 minutes later by a one hour constant infusion. Results The PBPK model provides a good description of the experimental data over a large range of input dosage, subject age and fat fraction. Only one adjustable parameter (the liver clearance is required to describe the constant infusion phase for each individual subject. In order to fit the bolus injection phase, for 10 or the 24 subjects it was necessary to assume that a fraction of the bolus dose was sequestered and then slowly released from the lungs (characterized by two additional parameters. The average weighted residual error (WRE of the PBPK model fit to the both the bolus and infusion phases was 15%; similar to the WRE for just the constant infusion phase obtained by Schnider et. al. using a 6-parameter NONMEM compartmental model. Conclusion A PBPK model using standard human parameters and a simple description of tissue binding provides a good description of human propofol kinetics. The major advantage of a

  1. Cocrystals and alloys of nitazoxanide: enhanced pharmacokinetics.

    Science.gov (United States)

    Suresh, Kuthuru; Mannava, M K Chaitanya; Nangia, Ashwini

    2016-03-18

    Two isomorphous cocrystals of nitazoxanide (NTZ) with p-aminosalicylic acid (PASA) and p-aminobenzoic acid (PABA) as well as their alloys were prepared by slurry and grinding techniques. The cocrystals exhibit faster dissolution rates and higher pharmacokinetic properties compared to the reference drug, and surprisingly the cocrystal alloy NTZ-PABA : NTZ-PASA (0.75 : 0.25) exhibited 4 fold higher bioavailability of NTZ in Sprague Dawley rats. This study opens the opportunity for cocrystal alloys as improved medicines.

  2. Pharmacokinetic comparison of seven 8-methoxypsoralen brands

    DEFF Research Database (Denmark)

    Menne, T; Andersen, Klaus Ejner; Larsen, E

    1981-01-01

    The pharmacokinetics of seven 8-MOP brands were evaluated in 7 volunteers using an incomplete bloc design. After a single oral dose the 8-MOP plasma level was followed for 3 hours. The plasma concentration was measured with a gas chromatographic - mass spectrometric method, using an isotopic...... dilution technique. The different brands could be divided into three groups. Two gave a high maximum concentration, four a medium, and one a low concentration. The large interbrand variation observed in this study can explain the variations in the results of the treatment and the differing numbers...

  3. Pharmacokinetics and pharmacodynamics of the proton pump inhibitors.

    Science.gov (United States)

    Shin, Jai Moo; Kim, Nayoung

    2013-01-01

    Proton pump inhibitor (PPI) is a prodrug which is activated by acid. Activated PPI binds covalently to the gastric H(+), K(+)-ATPase via disulfide bond. Cys813 is the primary site responsible for the inhibition of acid pump enzyme, where PPIs bind. Omeprazole was the first PPI introduced in market, followed by pantoprazole, lansoprazole and rabeprazole. Though these PPIs share the core structures benzimidazole and pyridine, their pharmacokinetics and pharmacodynamics are a little different. Several factors must be considered in understanding the pharmacodynamics of PPIs, including: accumulation of PPI in the parietal cell, the proportion of the pump enzyme located at the canaliculus, de novo synthesis of new pump enzyme, metabolism of PPI, amounts of covalent binding of PPI in the parietal cell, and the stability of PPI binding. PPIs have about 1hour of elimination half-life. Area under the plasmic concentration curve and the intragastric pH profile are very good indicators for evaluating PPI efficacy. Though CYP2C19 and CYP3A4 polymorphism are major components of PPI metabolism, the pharmacokinetics and pharmacodynamics of racemic mixture of PPIs depend on the CYP2C19 genotype status. S-omeprazole is relatively insensitive to CYP2C19, so better control of the intragastric pH is achieved. Similarly, R-lansoprazole was developed in order to increase the drug activity. Delayed-release formulation resulted in a longer duration of effective concentration of R-lansoprazole in blood, in addition to metabolic advantage. Thus, dexlansoprazole showed best control of the intragastric pH among the present PPIs. Overall, PPIs made significant progress in the management of acid-related diseases and improved health-related quality of life.

  4. [Preparation of diclofenac sodium liposomes and its ocular pharmacokinetics].

    Science.gov (United States)

    Sun, Kao-xiang; Wang, Ai-ping; Huang, Li-jun; Liang, Rong-cai; Liu, Ke

    2006-11-01

    To prepare diclofenac sodium liposomes and observe its ocular pharmacokinetics in rabbits. The diclofenac sodium cationic liposomes were prepared by reverse-phase evaporation methods and the formula of liposome was optimized with uniform design. HPLC method was established and validated for the determination of diclofenac sodium in precornea, cornea and aqueous humor of rabbit eye. Liposome and eyedrop solution 50 microL with total 50 microg diclofenac sodium were instilled to eyes of rabbits, separately. Samples of tear, cornea and aqueous humor were collected at different time intervals after rabbits were sacrificed. The ocular pharmacokinetics was investigated by the concentration-time data of tear, cornea and aqueous humor. The mean particle size of the diclofenac sodium liposomes was 226.5 nm with zeta potential of + 18. 1 mV. The entrapment efficiency reached 63%. Compared with solution, liposome was characterized by slower clearance in precornea. The concentration of diclotenac in cornea and aqueous humor instilled with liposome were higher than that with eye-drop solution. Cmax of diclofenac sodium in aqueous humor instilled with liposome and eye-drop solution were (0.69 +/- 0.25) and (0.48 +/- 0.19) microg x mL(-1) and (36.68 +/- 11.7) and (21.82 +/- 8.6) microg x g(-1) in cornea, respectively. But no significant difference were found to Tmax in aqueous humor and cornea between liposome and eyedrop, T(1/2) of diclofenac in aqueous humor and cornea with liposoine were longer than that with eye-drop solution. The ocular bioavailability of liposome in aqueous humor was 211% compared with that of eyedrop. Diclofenac sodium cationic liposomes can increase the corneal contact time, enhance the corneal permeability of diclofenac sodium and improve its ocular bioavailability.

  5. Pediatric Obesity: Pharmacokinetic Alterations and Effects on Antimicrobial Dosing.

    Science.gov (United States)

    Natale, Stephanie; Bradley, John; Nguyen, William Huy; Tran, Tri; Ny, Pamela; La, Kirsten; Vivian, Eva; Le, Jennifer

    2017-03-01

    Limited data exist for appropriate drug dosing in obese children. This comprehensive review summarizes pharmacokinetic (PK) alterations that occur with age and obesity, and these effects on antimicrobial dosing. A thorough comparison of different measures of body weight and specific antimicrobial agents including cefazolin, cefepime, ceftazidime, daptomycin, doripenem, gentamicin, linezolid, meropenem, piperacillin-tazobactam, tobramycin, vancomycin, and voriconazole is presented. PubMed (1966-July 2015) and Cochrane Library searches were performed using these key terms: children, pharmacokinetic, obesity, overweight, body mass index, ideal body weight, lean body weight, body composition, and specific antimicrobial drugs. PK studies in obese children and, if necessary, data from adult studies were summarized. Knowledge of PK alterations stemming from physiologic changes that occur with age from the neonate to adolescent, as well as those that result from increased body fat, become an essential first step toward optimizing drug dosing in obese children. Excessive amounts of adipose tissue contribute significantly to body size, total body water content, and organ size and function that may modify drug distribution and clearance. PK studies that evaluated antimicrobial dosing primarily used total (or actual) body weight (TBW) for loading doses and TBW or adjusted body weight for maintenance doses, depending on the drugs' properties and dosing units. PK studies in obese children are imperative to elucidate drug distribution, clearance, and, consequently, the dose required for effective therapy in these children. Future studies should evaluate the effects of both age and obesity on drug dosing because the incidence of obesity is increasing in pediatric patients. © 2017 Pharmacotherapy Publications, Inc.

  6. Pharmacokinetic characterization of three novel 4-mg nicotine lozenges
.

    Science.gov (United States)

    Sukhija, Manpreet; Srivastava, Reena; Kaushik, Aditya

    2018-03-01

    Nicotine replacement therapy (NRT) increases the probability of smoking cessation. This study was conducted to determine if three prototype 4-mg nicotine lozenges produced locally in India were bioequivalent to a globally marketed reference product, Nicorette® 4-mg nicotine lozenge. Healthy adult smokers (N = 39) were treated with three prototype 4-mg nicotine lozenges in comparison with a reference 4-mg lozenge in this single-center, randomized, open-label, single-dose, 4-way crossover study. Pharmacokinetic sampling was obtained to test for bioequivalence using maximal plasma concentration (Cmax) and extent of absorption (AUC0-t). Secondarily, AUC;0-∞, time to maximal plasma concentration (tmax), half-life (T1/2), elimination rate constant (Kel), and safety of the prototype lozenges versus the reference lozenge were compared. Each prototype 4-mg nicotine lozenge was found to be bioequivalent to the reference 4-mg nicotine lozenge based on the ratio of geometric means and 90% confidence intervals for Cmax, AUC0-t, and AUC;0-∞. Although tmax; was significantly longer for prototype III, all four lozenges achieved maximum plasma nicotine concentrations at a median of 1.5 hours. The safety profiles of the three prototype 4-mg lozenges did not differ from that of the 4-mg reference product. Each prototype 4-mg nicotine lozenge was bioequivalent to the reference 4-mg nicotine lozenge and was well tolerated. Furthermore, as these bioequivalent prototypes differed in in-vitro dissolution profiles, these data suggest that performance from the in -vitro method deployed is not a firm predictor of pharmacokinetic behavior.
.

  7. Investigation of the cytotoxicity, apoptosis and pharmacokinetics of Raddeanin A.

    Science.gov (United States)

    Gu, Guiying; Qi, Huanhuan; Jiang, Tianyue; Ma, Bo; Fang, Zheng; Xu, Hong; Zhang, Qi

    2017-03-01

    Raddeanin A, one of the triterpenoid saponins extracted from Anemone raddeana rhizome of the Ranunculaceae family, has demonstrated the ability to inhibit the growth of human hepatic and gastric cancer cells. However, the effects of Raddeanin A on human colon cancer cells have not been investigated extensively. The present study aimed to examine the antiproliferative and apoptosis-inducing effects of Raddeanin A on the HCT-116 human colon cancer cell line in vitro , and evaluate the pharmacokinetic and biodistribution properties of Raddeanin A in mice following a single oral administration. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to assess the in vitro cytotoxicity of Raddeanin A against HCT-116 cells. 4',6-Diamidino-2-phenylindole, dihydrochloride staining and flow cytometry were performed to further examine the apoptosis-inducing capability of Raddeanin A. The concentrations of Raddeanin A in the plasma and tissues were analyzed using liquid chromatography-tandem mass spectrometry. Raddeanin A showed a dose-dependent antiproliferative effect towards the HCT-116 cells, with a half maximal inhibitory concentration of ~1.4 µM. Treatment with Raddeanin A resulted in a significant induction of apoptosis, observed as apparent morphological changes of the nuclei, with a total apoptotic ratio of 41.8% at a concentration of 3 µM. Low concentrations of Raddeanin A were detected in the heart, liver, spleen, lung, kidney and plasma of the mice following oral administration, however, the majority of the Raddeanin A was distributed in the intestinal tract, particularly in the colon and caecum. These present study confirmed the growth-inhibitory and apoptosis-inducing effects of Raddeanin A on HCT-116 cells and performed preliminary examinations of its pharmacokinetic properties, which provide a foundation for further investigating the inhibitory mechanism on the colon cancer cells in vivo .

  8. Pharmacokinetics and pharmacodynamics of meldonium in exercised thoroughbred horses.

    Science.gov (United States)

    Knych, Heather K; Stanley, Scott D; McKemie, Dan S; Arthur, Rick M; Bondesson, Ulf; Hedeland, Mikael; Thevis, Mario; Kass, Philip H

    2017-09-01

    Although developed as a therapeutic medication, meldonium has found widespread use in human sports and was recently added to the World Anti-Doping Agency's list of prohibited substances. Its reported abuse potential in human sports has led to concern by regulatory authorities about the possible misuse of meldonium in equine athletics. The potential abuse in equine athletes along with the limited data available regarding the pharmacokinetics and pharmacodynamics of meldonium in horses necessitates further study. Eight exercised adult thoroughbred horses received a single oral dose of 3.5, 7.1, 14.3 or 21.4 mg/kg of meldonium. Blood and urine samples were collected and analyzed using liquid chromatography tandem mass spectrometry. Pharmacokinetic parameters were determined using non-compartmental analysis. Maximum serum concentrations ranged from 440.2 to 1147 ng/mL and the elimination half-life from 422 to 647.8 h. Serum concentrations were below the limit of quantitation by days 4, 7, 12 and 12 for doses of 3.5, 7.1, 14.3 and 21.4 mg/kg, respectively. Urine concentrations were below the limit of detection by day 44 following administration of 3.5 mg/kg and day 51 for all other dose groups. No adverse effects were observed following meldonium administration. While the group numbers were small, changes in heart rate were observed in the 3.5 mg/kg dose group (n = 1). Glucose concentrations changed significantly in all dose groups studied (n = 2 per dose group). Similar to that reported for humans, the detection time of meldonium in biological samples collected from horses is prolonged, which should allow for satisfactory regulation in performance horses. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  9. The influence of paroxetine on the pharmacokinetics of atomoxetine and its main metabolite.

    Science.gov (United States)

    Todor, Ioana; Popa, Adina; Neag, Maria; Muntean, Dana; Bocsan, Corina; Buzoianu, Anca; Vlase, Laurian; Gheldiu, Ana-Maria; Chira, Ruxandra; Briciu, Corina

    2015-01-01

    To evaluate the effects of paroxetine on the pharmacokinetics of atomoxetine and its main metabolite, 4-hydroxyatomoxetine-O-glucuronide, after coadministration of atomoxetine and paroxetine in healthy volunteers. 22 healthy volunteers, extensive metabolizers, took part in this open-label, non-randomized, clinical trial. The study consisted of two periods: Reference, when a single oral dose of 25 mg atomoxetine was administrated to each subject and Test, when 25 mg atomoxetine and 20 mg paroxetine were coadministered. Between the two periods, the volunteers received an oral daily dose of 20-40 mg paroxetine, for 6 days. Atomoxetine and 4-hydroxyatomoxetine-O-glucuronide plasma concentrations were determined within the first 48 hours following drug administration. The pharmacokinetic parameters of both compounds were assessed using a non-compartmental method and the analysis of variance aimed at identifying any statistical significant differences between the pharmacokinetic parameters of atomoxetine and its main metabolite, corresponding to each study period. Paroxetine modified the pharmacokinetic parameters of atomoxetine. Cmax increased from 221.26±94.93 to 372.53±128.28 ng/mL, while AUC0-t and AUC0-∞ also increased from 1151.19±686.52 to 6452.37±3388.76 ng*h/mL, and from 1229.15±751.04 to 7111.74±4195.17 ng*h/mL respectively. The main metabolite pharmacokinetics was also influenced by paroxetine intake, namely Cmax, AUC0-t and AUC0-∞ decreased from 688.76±270.27 to 131.01±100.43 ng*h/mL, and from 4810.93±845.06 to 2606.04±923.88 and from 4928.55±853.25 to 3029.82 ±941.84 respectively. Multiple-dose paroxetine intake significantly influenced atomoxetine and its active metabolite pharmacokinetics, causing a 5.8-fold increased exposure to atomoxetine and 1.6-fold reduced exposure to 4-hydroxyatomoxetine-O-glucuronide.

  10. Effect of methamphetamine on the pharmacokinetics of dextromethorphan and midazolam in rats.

    Science.gov (United States)

    Dostalek, M; Hadasova, E; Hanesova, M; Pistovcakova, J; Sulcova, A; Jurica, J; Tomandl, J; Linhart, I

    2005-01-01

    Methamphetamine is the fourth most frequently reported compound associated with drug abuse on admission of patients to treatment centres after cocaine, heroin and marijuana. It is metabolized in the organism with a reaction that is catalyzed by cytochrome P450, mainly by the CYP2D and CYP3A subfamily, 4-hydroxyamphetamine and amphetamine being dominant metabolites. The present pharmacokinetic study was undertaken to investigate the possible influence of methamphetamine (10 mg/kg, i.p., once daily for six days) on the pharmacokinetics of dextromethorphane as a model substrate for rat cytochrome P-4502D2 and midazolam as a model substrate for CYP3A1/2. Animals received a single injection of dextromethorphane (10 mg/kg) or midazolam (5 mg/kg) in the tail vein 24 h after the last dose of methamphetamine or administration of placebo. The results of pharmacokinetic analysis showed a significantly increased rate of dextrorphane and 3-hydroxymorphinan formation, and a marked stimulatory effect of methamphetamine on CYP2D2 metabolic activity. Similarly, the kinetics of midazolam's metabolic conversion to hydroxy derivates of midazolam indicated a significant increase in CYP3A1/2 activity. The results showed that the administration of methamphetamine significantly stimulated the metabolic activity of CYP2D2 as well as that of CYP3A1/2. With regard to the high level of homology between human and rat CYP isoforms studied, the results may have a clinical impact on future pharmacotherapy for methamphetamine abuse.

  11. Pharmacokinetics of topiramate during pregnancy

    DEFF Research Database (Denmark)

    Ohman, Inger; Sabers, Anne; de Flon, Pierre

    2009-01-01

    PURPOSE: To study the effects of pregnancy on plasma concentrations of topiramate (TPM). METHODS: An established routine fluorescence polarization immunoassay (FPIA) method was used to determine TPM concentrations in 15 women with epilepsy treated with TPM during altogether 17 pregnancies. RESULTS......: In 10 pregnancies, where samples were available from all three trimesters, the mean TPM dose/concentration ratio (D/C-ratio) was significantly higher than outside pregnancy baseline value 37.3 L/day (+/-15.9), during the 2nd, 67.5L/day (+/-23.4), and the 3rd trimester, 65.1L/day (+/-30.......4), but not during the 1st, 49.4 L/day (+/-29.4). Including seven additional pregnancies enrolled late with data only from the 3rd trimester, the mean D/C-ratio during the 3rd trimester was 67.4 L/day (+/-27.5) compared to baseline, 38.8L/day (+/-18.0), an average increase by 71.8%. There was a pronounced intra...

  12. Molecular fundamentals of drug interactions in the therapy of colorectal cancer

    Directory of Open Access Journals (Sweden)

    Katarzyna Regulska

    2014-03-01

    Full Text Available Rapid advances in the field of chemotherapy have resulted in the introduction of numerous antineoplastic drugs into clinical practice, which increased the efficiency of patient management. Also the prevalent use of combination treatment based on drug action synergy contributed to the improved clinical effect associated with cytotoxic drug administration. It seems, however, obvious that the multidirectional pharmacotherapy in oncology requires a thorough knowledge of drugs’ pharmaceutical behavior in order to maximize their collective action and prevent the occurrence of unintended drug interactions that could potentially impair treatment effectiveness. In fact, drug interactions constitute a serious problem for current oncology primarily resulting from a narrow therapeutic index specific for the majority of anticancer drugs. This, in turn, indicates that even slight deviations of their pharmacokinetics could cause significant clinical consequences, manifested by alteration of the toxicological profile or reduction of therapeutic efficiency. Hence, the investigation of molecular aspects underlying the mechanisms of various drug interactions seems to be essential for proper and safe patient management. The present article is devoted to the extensive subject of drug interactions occurring in the therapy of colorectal cancer. It presents the available literature data on both positive and negative effects of interactions and it discusses their mechanisms complying with their classification into pharmacokinetic and pharmacodynamic ones.

  13. [Molecular fundamentals of drug interactions in the therapy of colorectal cancer].

    Science.gov (United States)

    Regulska, Katarzyna; Stanisz, Beata; Regulski, Miłosz; Gieremek, Paulina

    2014-03-04

    Rapid advances in the field of chemotherapy have resulted in the introduction of numerous antineoplastic drugs into clinical practice, which increased the efficiency of patient management. Also the prevalent use of combination treatment based on drug action synergy contributed to the improved clinical effect associated with cytotoxic drug administration. It seems, however, obvious that the multidirectional pharmacotherapy in oncology requires a thorough knowledge of drugs' pharmaceutical behavior in order to maximize their collective action and prevent the occurrence of unintended drug interactions that could potentially impair treatment effectiveness. In fact, drug interactions constitute a serious problem for current oncology primarily resulting from a narrow therapeutic index specific for the majority of anticancer drugs. This, in turn, indicates that even slight deviations of their pharmacokinetics could cause significant clinical consequences, manifested by alteration of the toxicological profile or reduction of therapeutic efficiency. Hence, the investigation of molecular aspects underlying the mechanisms of various drug interactions seems to be essential for proper and safe patient management. The present article is devoted to the extensive subject of drug interactions occurring in the therapy of colorectal cancer. It presents the available literature data on both positive and negative effects of interactions and it discusses their mechanisms complying with their classification into pharmacokinetic and pharmacodynamic ones.

  14. Synergistic effect of the interaction between curcumin and diclofenac on the formalin test in rats.

    Science.gov (United States)

    De Paz-Campos, Marco A; Ortiz, Mario I; Chávez Piña, Aracely E; Zazueta-Beltrán, Liliana; Castañeda-Hernández, Gilberto

    2014-10-15

    The association of non-steroidal anti-inflammatory drugs with certain plant extracts can increase antinociceptive activity, permitting the use of lower doses and thus limiting side effects. Therefore, the aim objective of the current study was to examine the effects of curcumin on the nociception and pharmacokinetics of diclofenac in rats. Antinociception was assessed using the formalin test. Diluted formalin was injected subcutaneously into the dorsal surface of the right hind paw. Nociceptive behavior was quantified as the number of flinches of the injected paw during 60 min after injection, and a reduction in formalin-induced flinching was interpreted as an antinociceptive response. Rats were treated with oral diclofenac (1-31 mg/kg), curcumin (3.1-100 mg/kg) or the diclofenac-curcumin combination (2.4-38.4 mg/kg). To determine the possibility of a pharmacokinetic interaction, the oral bioavailability of diclofenac (10 mg/kg) was studied in presence and the absence of curcumin (31 mg/kg). Diclofenac, curcumin, or diclofenac-curcumin combination produced an antinociceptive effect on the formalin test. ED30 values were estimated for the individual drugs, and an isobologram was constructed. The derived theoretical ED30 for the antinociceptive effect (19.2 mg/kg) was significantly different from the observed experimental ED30 value (9.8 mg/kg); hence, the interaction between diclofenac and curcumin that mediates the antinociceptive effect was synergistic. Notwithstanding, the interaction does not appear to involve pharmacokinetic mechanisms, as oral curcumin failed to produce any significant alteration in oral diclofenac bioavailability. Data suggest that the diclofenac-curcumin combination can interact at the systemic level and may have therapeutic advantages for the clinical treatment of inflammatory pain. Copyright © 2014 Elsevier GmbH. All rights reserved.

  15. Drug pharmacokinetics and pharmacodynamics: Technological considerations

    International Nuclear Information System (INIS)

    Fowler, J.S.; Volkow, N.D.; Wolf, A.P.

    1992-01-01

    Additionally, the use of PET to examine drug pharmacokinetics and pharmacadynamics and the relationship of these properties to the behavioral, therapeutic and toxic properties of drugs and substances of abuse is emerging as a powerful new scientific tool. The pharmacokinetic properties of a drug, which comprises all of the biological processes which determine the fraction of the drug available, can be measured using the labeled drug itself. For example, the labeled drug can be used to measure the absolute uptake, regional distribution and kinetics of a drug at its site of action in the body. Additionally the labeled drug and whole body its labeled metabolites and thus provide information an potential toxic effects as well as tissue half lives. On the other hand, different labeled tracers can be used to assess drug pharmacodynamics which include the biological Processes involved in the drug's effects. For example, with appropriate radiotracers, the effects of a drug on metabolism, neurotransmitter activity, blood flew, enzyme activity or other processes can be probed

  16. Clinical Population Pharmacokinetics and Toxicodynamics of Linezolid

    Science.gov (United States)

    Boak, Lauren M.; Rayner, Craig R.; Grayson, M. Lindsay; Paterson, David L.; Spelman, Denis; Khumra, Sharmila; Capitano, Blair; Forrest, Alan; Li, Jian

    2014-01-01

    Thrombocytopenia is a common side effect of linezolid, an oxazolidinone antibiotic often used to treat multidrug-resistant Gram-positive bacterial infections. Various risk factors have been suggested, including linezolid dose and duration of therapy, baseline platelet counts, and renal dysfunction; still, the mechanisms behind this potentially treatment-limiting toxicity are largely unknown. A clinical study was conducted to investigate the relationship between linezolid pharmacokinetics and toxicodynamics and inform strategies to prevent and manage linezolid-associated toxicity. Forty-one patients received 42 separate treatment courses of linezolid (600 mg every 12 h). A new mechanism-based, population pharmacokinetic/toxicodynamic model was developed to describe the time course of plasma linezolid concentrations and platelets. A linezolid concentration of 8.06 mg/liter (101% between-patient variability) inhibited the synthesis of platelet precursor cells by 50%. Simulations predicted treatment durations of 5 and 7 days to carry a substantially lower risk than 10- to 28-day therapy for platelet nadirs of linezolid therapy and large between-patient variability, close monitoring of patients for development of toxicity is important. Dose individualization based on plasma linezolid concentration profiles and platelet counts should be considered to minimize linezolid-associated thrombocytopenia. Overall, oxazolidinone therapy over 5 to 7 days even at relatively high doses was predicted to be as safe as 10-day therapy of 600 mg linezolid every 12 h. PMID:24514086

  17. Pharmacokinetics of rilmenidine in healthy subjects

    International Nuclear Information System (INIS)

    Genissel, P.; Bromet, N.; Fourtillan, J.B.; Mignot, A.; Albin, H.

    1988-01-01

    Rilmenidine is a novel alpha 2-adrenoceptor agonist, used in the treatment of mild or moderate hypertension at the oral dose of 1 mg once or twice daily. The pharmacokinetic parameters were investigated after single or repeated administration in healthy subjects, using labeled and unlabeled compounds. Rilmenidine was rapidly and extensively absorbed, with an absolute bioavailability factor close to 1 and a maximal plasma concentration achieved within 2 hours. Rilmenidine was not subject to presystemic metabolism. Distribution was independent of the free fraction because rilmenidine was weakly bound to plasma proteins (less than 10%). The volume of distribution was approximately 5 l.kg-1 (315 liters). Elimination was rapid with a total body plasma clearance of approximately 450 ml.min-1 and an elimination half-life of approximately 8 hours. Renal excretion was the major elimination process (two-thirds of the total clearance). Metabolism was very poor, with a renal elimination of rilmenidine as the parent drug (urinary fraction of rilmenidine was about 65% and no metabolite plasma levels were detected). Linear pharmacokinetics were demonstrated for rilmenidine from 0.5 to 2 mg but, at 3 mg, a slight deviation from linearity was observed. In repeated administration, the linear disposition of rilmenidine with dose was confirmed

  18. Preparation and ocular pharmacokinetics of ganciclovir liposomes.

    Science.gov (United States)

    Shen, Yan; Tu, Jiasheng

    2007-12-07

    Ophthalmic liposomes of ganciclovir (GCV) were prepared by the reverse phase evaporation method, and their ocular pharmacokinetics in albino rabbits were compared with those obtained after dosing with GCV solution. The in vitro transcorneal permeability of GCV liposomes was found to be 3.9-fold higher than that of the solution. After in vivo instillation in albino rabbits, no difference was found in the precorneal elimination rate of GCV from liposome vs solution dosing. The aqueous humor concentration-time profiles of both liposomes and solution were well described by 2-compartmental pharmacokinetics with first-order absorption. The area under the curve of the aqueous humor concentration-time profiles of GCV liposomes was found to be 1.7-fold higher than that of GCV solution. Ocular tissue distribution of GCV from liposomes was 2 to 10 times higher in the sclera, cornea, iris, lens, and vitreous humor when compared with those observed after solution dosing. These results suggested that liposomes may hold some promise in ocular GCV delivery.

  19. Physiologic and Pharmacokinetic Changes in Pregnancy

    Directory of Open Access Journals (Sweden)

    Maged eCostantine

    2014-04-01

    Full Text Available Physiologic changes in pregnancy induce profound alterations to the pharmacokinetic properties of many medications. These changes affect distribution, absorption, metabolism, and excretion of drugs, and thus may impact their pharmacodynamic properties during pregnancy. Pregnant women undergo several adaptations in many organ systems. Some adaptations are secondary to hormonal changes in pregnancy, while others occur to support the gravid woman and her developing fetus. Some of the changes in maternal physiology during pregnancy include, for example, increased maternal fat and total body water, decreased plasma protein concentrations, especially albumin, increased maternal blood volume, cardiac output and blood flow to the kidneys and uteroplacental unit, and decreased blood pressure. The maternal blood volume expansion occurs at a larger proportion than the increase in red blood cell mass, which results in physiologic anemia and hemodilution. Other physiologic changes include increased tidal volume, partially compensated respiratory alkalosis, delayed gastric emptying and gastrointestinal motility, and altered activity of hepatic drug metabolizing enzymes. Understating these changes and their profound impact on the pharmacokinetic properties of drugs in pregnancy is essential to optimize maternal and fetal health.

  20. Comparative Pharmacokinetics of Levofloxacin in Healthy and Renal Damaged Muscovy Ducks following Intravenous and Oral Administration

    Directory of Open Access Journals (Sweden)

    Mohamed Aboubakr

    2014-01-01

    Full Text Available The pharmacokinetics aspects of levofloxacin were studied in healthy and experimentally renal damaged Muscovy ducks after single intravenous (IV and oral (PO dose of 10 mg kg−1 bwt. Following IV administration, elimination half-life (t1/2(β and mean residence time (MRT were longer in renal damaged ducks than in healthy ones. Total clearance (Cltot in renal damaged ducks (0.20 L kg−1 h−1 was significantly lower as compared to that in healthy ones (0.41 L kg−1 h−1. Following PO administration, the peak serum concentration (Cmax was higher in renal damaged than in healthy ducks and was achieved at maximum time (tmax of 2.47 and 2.05 h, respectively. The drug was eliminated (t1/2(el at a significant slower rate (3.94 h in renal damaged than in healthy ducks (2.89 h. The pharmacokinetic profile of levofloxacin is altered in renal damaged ducks due to the increased serum levofloxacin concentrations compared with that in clinically healthy ducks. Oral administration of levofloxacin at 10 mg kg−1 bwt may be highly efficacious against susceptible bacteria in ducks. Also, the dose of levofloxacin should be reduced in renal damaged ducks. Pharmacokinetic/pharmacodynamic integration revealed significantly higher values for Cmax/MIC and AUC/MIC ratios in renal damaged ducks than in healthy ones, indicating the excellent pharmacokinetic characteristics of levofloxacin in renal damaged ducks.

  1. A randomized, 2-period, crossover design study to assess the effects of dexlansoprazole, lansoprazole, esomeprazole, and omeprazole on the steady-state pharmacokinetics and pharmacodynamics of clopidogrel in healthy volunteers.

    Science.gov (United States)

    Frelinger, Andrew L; Lee, Ronald D; Mulford, Darcy J; Wu, Jingtao; Nudurupati, Sai; Nigam, Anu; Brooks, Julie K; Bhatt, Deepak L; Michelson, Alan D

    2012-04-03

    The aim of this study was to assess the effects of different proton pump inhibitors (PPIs) on the steady-state pharmacokinetics and pharmacodynamics of clopidogrel. Metabolism of clopidogrel requires cytochrome P450s (CYPs), including CYP2C19. However, PPIs may inhibit CYP2C19, potentially reducing the effectiveness of clopidogrel. A randomized, open-label, 2-period, crossover study of healthy subjects (n = 160, age 18 to 55 years, homozygous for CYP2C19 extensive metabolizer genotype, confined, standardized diet) was conducted. Clopidogrel 75 mg with or without a PPI (dexlansoprazole 60 mg, lansoprazole 30 mg, esomeprazole 40 mg, or, as a positive control to maximize potential interaction and demonstrate assay sensitivity, omeprazole 80 mg) was given daily for 9 days. Pharmacokinetics and pharmacodynamics were assessed on days 9 and 10. Pharmacodynamic end-points were vasodilator-stimulated phosphoprotein P2Y(12) platelet reactivity index, maximal platelet aggregation to 5 and 20 μmol/l adenosine diphosphate, and VerifyNow P2Y12 platelet response units. Pharmacokinetic and pharmacodynamic responses with omeprazole demonstrated assay sensitivity. The area under the curve for clopidogrel active metabolite decreased significantly with esomeprazole but not with dexlansoprazole or lansoprazole. Similarly, esomeprazole but not dexlansoprazole or lansoprazole significantly reduced the effect of clopidogrel on vasodilator-stimulated phosphoprotein platelet reactivity index. All PPIs decreased the peak plasma concentration of clopidogrel active metabolite (omeprazole > esomeprazole > lansoprazole > dexlansoprazole) and showed a corresponding order of potency for effects on maximal platelet aggregation and platelet response units. Generation of clopidogrel active metabolite and inhibition of platelet function were reduced less by the coadministration of dexlansoprazole or lansoprazole with clopidogrel than by the coadministration of esomeprazole or omeprazole. These

  2. The effect of grape seed extract on the pharmacokinetics of dextromethorphan in healthy volunteers.

    Science.gov (United States)

    Goey, Andrew K L; Meijerman, Irma; Beijnen, Jos H; Schellens, Jan H M

    2013-11-01

    Grape seed extract (GSE) has been shown to inhibit the cytochrome P450 (CYP) 2D6 isoenzyme in vitro. To determine the clinical effect of GSE on CYP2D6, the pharmacokinetic interaction between GSE and the sensitive CYP2D6 probe dextromethorphan in healthy adult volunteers was examined. In this open label, randomized, cross-over study, 30 subjects were assigned to cohort A or B. Both cohorts ingested 30 mg dextromethorphan hydrobromide on day 1 and day 10. Cohort A received 100 mg GSE capsules three times daily on days 8, 9 and 10, while cohort B started with GSE on day -1 until day 1. After urine collection (0-8 h) on day 1 and day 10, the urinary dextromethorphan to dextrorphan metabolic ratio was determined. Among 28 evaluable subjects, an increase of the urinary metabolic ratio was observed in 16 subjects (57 %). The mean metabolic ratio (± standard deviation) before and after GSE supplementation was 0.41 (± 0.56) and 0.48 (± 0.59), respectively. This result was neither statistically (P = 0.342) nor clinically [geometric mean ratio 1.10, 90 % CI (0.93-1.30)] significant. Further, the majority (73 %) of the included subjects did not experience any adverse events after intake of dextromethorphan or GSE. Supplementation of GSE did not significantly affect the urinary dextromethorphan to dextrorphan metabolic ratio in healthy volunteers. The results of this clinical study indicate that GSE appears to be safe to combine with drugs extensively metabolized by CYP2D6, such as dextromethorphan and tamoxifen.

  3. Uranium chemistry: significant advances

    International Nuclear Information System (INIS)

    Mazzanti, M.

    2011-01-01

    The author reviews recent progress in uranium chemistry achieved in CEA laboratories. Like its neighbors in the Mendeleev chart uranium undergoes hydrolysis, oxidation and disproportionation reactions which make the chemistry of these species in water highly complex. The study of the chemistry of uranium in an anhydrous medium has led to correlate the structural and electronic differences observed in the interaction of uranium(III) and the lanthanides(III) with nitrogen or sulfur molecules and the effectiveness of these molecules in An(III)/Ln(III) separation via liquid-liquid extraction. Recent work on the redox reactivity of trivalent uranium U(III) in an organic medium with molecules such as water or an azide ion (N 3 - ) in stoichiometric quantities, led to extremely interesting uranium aggregates particular those involved in actinide migration in the environment or in aggregation problems in the fuel processing cycle. Another significant advance was the discovery of a compound containing the uranyl ion with a degree of oxidation (V) UO 2 + , obtained by oxidation of uranium(III). Recently chemists have succeeded in blocking the disproportionation reaction of uranyl(V) and in stabilizing polymetallic complexes of uranyl(V), opening the way to to a systematic study of the reactivity and the electronic and magnetic properties of uranyl(V) compounds. (A.C.)

  4. A metabolic and pharmacokinetic comparison of theophylline and aminophylline (theophylline ethylenediamine).

    Science.gov (United States)

    Monks, T J; Smith, R L; Caldwell, J

    1981-02-01

    The metabolism and pharmacokinetics of intravenously administered theophylline and aminophylline (theophylline ethylenediamine) have been studied in 3 volunteers, using 14C-labelled theophylline. Both compounds were metabolized extensively and 1,3-dimethyluric acid, 1-methyluric acid, 3-methylxanthine and two unknown minor metabolites were excreted in the urine, in addition to theophylline. The elimination of theophylline, 1,3-dimethyluric acid, 1-methyluric acid and the unknown metabolites followed first-order kinetics, but that of 3-methylxanthine followed Michaelis-Menten kinetics. When given as aminophylline, theophylline was metabolized more rapidly and extensively than when given alone. The recovery of 14C in the urine was significantly higher after aminophylline than after theophylline. Abstention from intake of dietary methylxanthines for 7 days resulted in more rapid and extensive metabolism of aminophylline compared with results from the same subjects on their usual diets. The results indicate that, from a metabolic and pharmacokinetic viewpoint, aminophylline and theophylline are not equivalent.

  5. Isolation, characterization, and in rats plasma pharmacokinetic study of a new triterpenoid saponin from Dianthus superbus.

    Science.gov (United States)

    Ren, Yina; Xu, Xiaobao; Zhang, Qianlan; Lu, Yongzhuang; Li, Ximin; Zhang, Lin; Tian, Jingkui

    2017-02-01

    One new oleanolic acid triterpenoid saponin, 3-O-β-D-glucopyranosyl olean-11, 13(18)-diene-23,28-dioic acid, (hereafter referred to as DS-1) was isolated from the traditional Chinese medicinal plant Dianthus superbus (D. superbus). DS-1 plays an important role in the bioactivity of D. superbus. Thus, a sensitive, reliable and accurate reversed-phased liquid chromatography with tandem mass spectrometry (LC-MS/MS) in negative ion mode was developed and validated for the quantification and pharmacokinetic study of DS-1 in rats plasma. The pharmacokinetic profile showed that DS-1 was rapidly absorbed and eliminated in plasma, indicating that significant accumulation of the compound in biological specimen is unlikely. In addition, poor absorption into systemic circulation was observed after oral administration of DS-1, resulting in low absolute bioavailability (0.92 %).

  6. Pharmacokinetic analysis of Gd-DTPA enhancement in dynamic MR of breast carcinoma

    International Nuclear Information System (INIS)

    Hess, T.; Knopp, M.V.; Hoffmann, U.; Brix, G.; Junkermann, H.; Zuna, I.; Fournier, D. von; Kaick, G. van

    1994-01-01

    Dynamic Gd-DTPA enhanced MR of the breast was performed in one single slice in 27 patients with suspicious nodular lesions. The results could be histologically verified in all cases. A rapid spin-echo sequence with a time resolution of 8.75 s was used for the dynamic examination. The signal changes were analysed using a pharmacokinetic model which allowed parametrization of the contrast enhancement and transformation of the data into colour coded parameter images. The parameters allowed reliable distinction of 9 benign from 18 malignant lesions (p 21 ''). One fibroadenoma could not be distinguished from the carcinomas. Lymph node metastases and the pharmacokinetic parameter amplitude correlated significantly (p<0.05). (orig.)

  7. Development of a simple chromatographic method for the determination of piracetam in human plasma and its pharmacokinetic evaluation.

    Science.gov (United States)

    Barkat, K; Ahmad, M; Minhas, M U; Malik, M Z; Sohail, M

    2014-07-01

    The objective of study was to develop an accurate and reproducible HPLC method for determination of piracetam in human plasma and to evaluate pharmacokinetic parameters of 800 mg piracetam. A simple, rapid, accurate, precise and sensitive high pressure liquid chromatography method has been developed and subsequently validated for determination of piracetam. This study represents the results of a randomized, single-dose and single-period in 18 healthy male volunteers to assess pharmacokinetic parameters of 800 mg piracetam tablets. Various pharmacokinetic parameters were determined from plasma for piracetam and found to be in good agreement with previous reported values. The data was analyzed by using Kinetica® version 4.4 according to non-compartment model of pharmacokinetic analysis and after comparison with previous studies, no significant differences were found in present study of tested product. The major pharmacokinetic parameters for piracetam were as follows: t1/2 was (4.40 ± 0.179) h; Tmax value was (2.33 ± 0.105) h; Cmax was (14.53 ± 0.282) µg/mL; the AUC(0-∞) was (59.19 ± 4.402) µg · h/mL. AUMC(0-∞) was (367.23 ± 38.96) µg. (h)(2)/mL; Ke was (0.16 ± 0.006) h; MRT was (5.80 ± 0.227) h; Vd was (96.36 ± 8.917 L). A rapid, accurate and precise high pressure liquid chromatography method was developed and validated before the study. It is concluded that this method is very useful for the analysis of pharmacokinetic parameters, in human plasma and assured the safety and efficacy of piracetam, can be effectively used in medical practice. © Georg Thieme Verlag KG Stuttgart · New York.

  8. [Discussion about traditional Chinese medicine pharmacokinetics study based on first botanical drug approved by FDA].

    Science.gov (United States)

    Huang, Fanghua

    2010-04-01

    Pharmacokinetics study is one of main components of pharmaceuticals development. Food and Drug Administration (FDA) approved Veregen as the first botanical drug in 2006. This article introduced FDA's requirement on pharmacokinetics study of botanical drug and pharmacokinetics studies of Veregen, summarized current requirement and status quo of pharmacokinetics study on traditional Chinese medicine (TCM) and natural medicine in China, and discussed about pharmacokinetics study strategy for TCM and natural medicine.

  9. Mefloquine pharmacokinetics and mefloquine-artesunate effectiveness in Peruvian patients with uncomplicated Plasmodium falciparum malaria

    Directory of Open Access Journals (Sweden)

    Quezada Wilmer

    2009-04-01

    /ml (2,614–3,108 for Lariam, 2,500 ng/ml (2,363–2,713 for Mephaquin, and 2,750 ng/ml (2,550–3,000 for Mefloquina AC Farma. The pharmacokinetics of the three formulations were generally similar, with the exception of the Cmax of Mephaquin which was significantly different to that of Lariam (p = 0.04. Conclusion All three formulations had similar pharmacokinetics; in addition, the pharmacokinetics seen in this Peruvian population were similar to reports from other ethnic groups. All patients rapidly cleared their parasitaemia with no evidence of recrudescence by Day 56. Continued surveillance is needed to ensure that patients continue to receive optimal therapy.

  10. Population Pharmacokinetics and Pharmacodynamics of Meropenem in Nonobese, Obese, and Morbidly Obese Patients.

    Science.gov (United States)

    Chung, Eun Kyoung; Cheatham, S Christian; Fleming, Megan R; Healy, Daniel P; Kays, Michael B

    2017-03-01

    The study objective was to evaluate meropenem population pharmacokinetics and pharmacodynamics in nonobese, obese, and morbidly obese patients. Forty adult patients-11 nonobese (body mass index [BMI] calculate probability of target attainment (PTA) for 5 dosing regimens, infused over 0.5 and 3 hours, using fT>MIC of 40%, 54%, and 100% of the dosing interval. A 2-compartment linear-elimination model best described the serum concentration-time data, and creatinine clearance was significantly associated with systemic clearance. Pharmacokinetic parameters were not significantly different among patient groups. In patients with creatinine clearances ≥50 mL/min, all simulated dosing regimens achieved >90% PTA at 40% fT>MIC in all patient groups at MICs ≤2 mg/L. Only 500 mg q8h, infused over 0.5 hour, did not achieve >90% PTA at 54% fT>MIC in nonobese and morbidly obese patients. At 100% fT>MIC, 1 g q6h and 2 g q8h, infused over 3 hours, reliably achieved >90% PTA in all patient groups. Meropenem pharmacokinetics are comparable among nonobese, obese, and morbidly obese patients. Standard dosing regimens provide adequate pharmacodynamic exposures for susceptible pathogens at 40% and 54% fT>MIC, but prolonged infusions of larger doses are needed for adequate exposures at 100% fT>MIC. Dosage adjustments based solely on body weight are unnecessary. © 2016, The American College of Clinical Pharmacology.

  11. Comparison of pharmacokinetic variables for creatinine and iohexol in dogs with various degrees of renal function.

    Science.gov (United States)

    Collignon, Cécile M; Heiene, Reidun; Queau, Yann; Reynolds, Brice S; Craig, Amanda J; Concordet, Didier; Harran, Nathaniel X; Risøen, Unni; Balouka, David; Faucher, Mathieu R; Eliassen, Knut A; Biourge, Vincent; Lefebvre, Hervé P

    2012-11-01

    To compare pharmacokinetics and clearances of creatinine and iohexol as estimates of glomerular filtration rate (GFR) in dogs with various degrees of renal function. 50 Great Anglo-Francais Tricolor Hounds with various degrees of renal function. Boluses of iohexol (40 mg/kg) and creatinine (647 mg/kg) were injected IV. Blood samples were collected before administration and 5 and 10 minutes and 1, 2, 4, 6, and 8 hours after administration. Plasma creatinine and iohexol concentrations were assayed via an enzymatic method and high-performance liquid chromatography, respectively. A noncompartmental approach was used for pharmacokinetic analysis. Pharmacokinetic variables were compared via a Bland-Altman plot and an ANOVA. Compared with results for creatinine, iohexol had a significantly higher mean ± SD plasma clearance (3.4 ± 0.8 mL/min/kg vs 3.0 ± 0.7 mL/min/kg) and a significantly lower mean volume of distribution at steady state (250 ± 37 mL/kg vs 539 ± 73 mL/kg), mean residence time (80 ± 31 minutes vs 195 ± 73 minutes), and mean elimination half-life (74 ± 20 minutes vs 173 ± 53 minutes). Despite discrepancies between clearances, especially for high values, the difference was dogs. Three dogs with a low GFR (dogs with a GFR within or above the reference range.

  12. Pharmacokinetic profile of phytoconstituent(s isolated from medicinal plants—A comprehensive review

    Directory of Open Access Journals (Sweden)

    Piyush Mehta

    2015-10-01

    Full Text Available Herbal medicine, the backbone of traditional medicine, has played an important role in human health and welfare for a long period. Traditional therapeutic approaches of regional significance are found in Africa, South and Central America, China, India, Tibet, Indonesia, and the Pacific Islands. The considerable scientific significance and commercial potential of traditional medicines have resulted in increased international attention and global market demands for herbal medicines, especially Chinese herbal medicines. Herbal medicines currently are the primary form of health care for the poor in the developing countries, and also are widely used as a supplement or substitute for conventional drugs in developed countries. These traditional medicines have a pivotal role in the treatment of various ailments and more than 50% of drugs used in Western pharmacopoeia are isolated from herbs or derived from modifications of chemicals found in plants. Herbal medicines usually contain a complex mixture of various bioactive molecules, which make its standardization complicated, and there is little information about all compounds responsible for pharmacological activity. Several research papers have been published that claim pharmacological activity of herbal medicines but few are discussing the role of the exact phytoconstituent. Understanding the pharmacokinetic profile of such phytoconstituents is essential. Although there are research papers that deal with pharmacokinetic properties of phytoconstituents, there are a number of phytoconstituents yet to be explored for their kinetic properties. This article reviews the pharmacokinetic profile of 50 different therapeutically effective traditional medicinal plants from the year 2003 onward.

  13. A Novel Paclitaxel Microemulsion Containing a Reduced Amount of Cremophor EL: Pharmacokinetics, Biodistribution, and In Vivo Antitumor Efficacy and Safety

    Science.gov (United States)

    Wang, Ying; Wu, Ke-Chun; Zhao, Bing-Xiang; Zhao, Xin; Wang, Xin; Chen, Su; Nie, Shu-Fang; Pan, Wei-San; Zhang, Xuan; Zhang, Qiang

    2011-01-01

    The purpose of this study was to prepare a novel paclitaxel (PTX) microemulsion containing a reduced amount of Cremophor EL (CrEL) which had similar pharmacokinetics and antitumor efficacy as the commercially available PTX injection, but a significantly reduced allergic effect due to the CrEL. The pharmacokinetics, biodistribution, in vivo antitumor activity and safety of PTX microemulsion was evaluated. The results of pharmacokinetic and distribution properties of PTX in the microemulsion were similar to those of the PTX injection. The antitumor efficacy of the PTX microemulsion in OVCRA-3 and A 549 tumor-bearing animals was similar to that of PTX injection. The PTX microemulsion did not cause haemolysis, erythrocyte agglutination or simulative reaction. The incidence and degree of allergic reactions exhibited by the PTX microemulsion group, with or without premedication, were significantly lower than those in the PTX injection group (P microemulsion had similar pharmacokinetics and anti-tumor efficacy to the PTX injection, but a significantly reduced allergic effect due to CrEL, indicating that the PTX microemulsion overcomes the disadvantages of the conventional PTX injection and is one way of avoiding the limitations of current injection product while providing suitable therapeutic efficacy. PMID:21331356

  14. Understanding alterations in drug handling with aging: a focus on the pharmacokinetics of maintenance immunosuppressants in the elderly.

    Science.gov (United States)

    Gabardi, Steven; Tullius, Stefan G; Krenzien, Felix

    2015-08-01

    This review presents current knowledge of the impact of age on the pharmacokinetics of maintenance immunosuppressants. Over the past decade, there has been a steady increase in older patients on organ transplant waiting lists. As a result, the average age of transplant recipients has significantly increased. The survival and quality-of-life benefits of transplantation in the elderly population have been demonstrated. Advancing age is associated with changes in immune responses, as well as changes in drug handling. Immunosenescence is a physiological part of aging and is linked to reduced rejection rates, but also higher rates of diabetes, infections and malignancies. Physiologic changes associated with age can have a significant impact on the pharmacokinetics of the maintenance immunosuppressive agents. Taken together, these age-related changes impact older transplant candidates and may have significant implications for managing immunosuppression in the elderly. Despite the lack of formal efficacy, safety and pharmacokinetic studies of individual immunosuppressants in the elderly transplant population, there are enough data available for practitioners to be able to adequately manage their older patients. A proficient understanding of the factors that impact the pharmacokinetics of the immunosuppressants in the elderly is essential to managing these patients successfully.

  15. Clinical relevance of cimetidine drug interactions.

    Science.gov (United States)

    Shinn, A F

    1992-01-01

    The excellent efficacy and tolerability profiles of H2-antagonists have established these agents as the leading class of antiulcer drugs. Attention has been focused on drug interactions with H2-antagonists as a means of product differentiation and because many patients are receiving multiple drug therapy. The main mechanism of most drug interactions involving cimetidine appears to be inhibition of the hepatic microsomal enzyme cytochrome P450, an effect which may be related to the different structures of H2-antagonists. Ranitidine appears to have less affinity than cimetidine for this system. There have been many published case reports and studies of drug interactions with cimetidine, but many of these have provided pharmacokinetic data only, with little information concerning the clinical significance of these findings. Nevertheless, the coadministration of cimetidine with drugs that have a narrow therapeutic margin (such as theophylline) may potentially result in clinically significant adverse effects. The monitoring of serum concentrations of drugs coadministered with cimetidine may reduce the risk of adverse events but does not abolish the problem. However, for most patients, concomitant administration of cimetidine with drugs possessing a wide therapeutic margin is unlikely to pose a significant problem.

  16. Population pharmacokinetics model of THC used by pulmonary route in occasional cannabis smokers.

    Science.gov (United States)

    Marsot, A; Audebert, C; Attolini, L; Lacarelle, B; Micallef, J; Blin, O

    Cannabis is the most widely used illegal drug in the world. Delta-9-tetrahydrocannabinol (THC) is the main source of the pharmacological effect. Some studies have been carried out and showed significant variability in the described models as the values of the estimated pharmacokinetic parameters. The objective of this study was to develop a population pharmacokinetic model for THC in occasional cannabis smokers. Twelve male volunteers (age: 20-28years, body weight: 62.5-91.0kg), tobacco (3-8 cigarette per day) and cannabis occasional smokers were recruited from the local community. After ad libitum smoking cannabis cigarette according a standardized procedure, 16 blood samples up to 72h were collected. Population pharmacokinetic analysis was performed using a non-linear mixed effects model, with NONMEM software. Demographic and biological data were investigated as covariates. A three-compartment model with first-order elimination fitted the data. The model was parameterized in terms of micro constants and central volume of distribution (V 1 ). Normal ALT concentration (6.0 to 45.0IU/l) demonstrated a statistically significant correlation with k 10 . The mean values (%Relative Standard Error (RSE)) for k 10 , k 12 , k 21 , k 23 , k 32 and V 1 were 0.408h -1 (48.8%), 4.070h -1 (21.4%), 0.022h -1 (27.0%), 1.070h -1 (14.3%), 1.060h -1 (16.7%) and 19.10L (39.7%), respectively. We have developed a population pharmacokinetic model able to describe the quantitative relationship between administration of inhaled doses of THC and the observed plasma concentrations after smoking cannabis. In addition, a linear relationship between ALT concentration and value of k 10 has been described and request further investigation. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Alterations in pentobarbital pharmacokinetics in response to parenteral and enteral alimentation in the rat.

    Science.gov (United States)

    Knodell, R G; Spector, M H; Brooks, D A; Keller, F X; Kyner, W T

    1980-12-01

    Recent in vitro observations suggest that the intestine, in addition to the liver, may be an important organ of first-pass drug metabolism. While a variety of changes in intestinal morphology and function in response to continuous parenteral and enteral nutrition have been documented, the effect of different routes of alimentation on intestinal drug metabolism has not been previously investigated. Objectives of this study were to assess the contribution of intestinal pentobarbital metabolism to overall in vivo pentobarbital pharmacokinetics in the rat and to determine if differences in pentobarbital pharmacokinetics were seen between parenterally and enterally nourished animals. After 7 days of continuous infusion of amino acid-glucose mixture via a gastric or jugular vein catheter, pharmacokinetic parameters were determined after 40 mg/kg of pentobarbital was given orally or into the portal or femoral vein. Reduced systemic availability of pentobarbital after oral administration as compared to portal vein injection was seen in both alimentation groups indicating that significant intestinal metabolism of pentobarbital occurred in vivo. Total area under the pentobarbital plasma concentration-time curve was significantly greater in parenterally nourished animals as compared with enterally alimented animals after oral, portal vein and systemic vein drug administration. Differences in pentobarbital, pharmacokinetics between the two alimentation groups appeared to be primarly due to effects on hepatic pentobarbital metabolism. While the mechanism producing these changes has not been defined, differences in gut hormones release and/or pancreatic secretion in response to the two routes of alimentation may be contributory. The widespread use of enteral and parenteral alimentation in clinical medicine suggests that studies to determine if nutrition route of administration similarly influences drug metabolism in humans may be indicated.

  18. Effects of the Chinese herbal formula "Zuojin Pill" on the pharmacokinetics of dextromethorphan in healthy Chinese volunteers with CYP2D6*10 genotype.

    Science.gov (United States)

    Qiu, Furong; Liu, Songcan; Miao, Ping; Zeng, Jin; Zhu, Leilei; Zhao, TongFang; Ye, Yujie; Jiang, Jian

    2016-06-01

    Zuojin Pill has been shown to inhibit the cytochrome P450 (CYP) 2D6 isoenzyme in vitro. In Chinese individuals, CYP 2D6*10 is the most common allele with reduced enzyme activity. In this study, we investigated the pharmacokinetic interaction between Zuojin Pill and the sensitive CYP2D6 probe dextromethorphan in healthy Chinese volunteers with CYP2D6*10 genotype. A pharmacokinetics interaction study was carried out in three groups with CYP2D6*1/*1 (n = 6), CYP2D6*1/*10 (n = 6), and CYP2D6*10/*10 (n = 6) genotypes. Each participant received a single oral dose of dextromethorphan (15 mg) followed by Zuojin Pill (3 g twice daily) for 7 days, and received 3 g Zuojin Pill with 15 mg dextromethorphan in the last day. Blood samples (0-24 h) and urine samples (0-12 h) were collected at baseline and after the administration of Zuojin Pill, and the samples' concentration of dextromethorphan and its main metabolite dextrorphan was determined. Compared to baseline values, co-administration of Zuojin Pill (3 g twice daily) for 7 days increased the AUC0-24 of dextromethorphan [mean (90 % CI)] by 3.00-fold (2.49∼3.61) and 1.71-fold (1.42∼2.06), and decreased oral clearance(CL/F) by 0.27-fold (0.2-0.40) and 0.57-fold (0.48-0.67) in the participants with CYP2D6*1/*1 and CYP2D6*1/*10 genotypes, respectively. In contrast, no significant change was observed in these pharmacokinetic parameters of the participants with CYP2D6*10/*10 genotype. These data demonstrated that administration of Zuojin Pill inhibited moderately CYP2D6-mediated metabolism of dextromethorphan in healthy volunteers. The inhibitory influence of CYP2D6 was greater in CYP2D6*1/*1 and CYP2D6*1/*10 groups than CYP2D6 *10/*10 group.

  19. Population Pharmacokinetics of Tracers: A New Tool for Medical Imaging?

    Science.gov (United States)

    Gandia, Peggy; Jaudet, Cyril; Chatelut, Etienne; Concordet, Didier

    2017-02-01

    Positron emission tomography-computed tomography is a medical imaging method measuring the activity of a radiotracer chosen to accumulate in cancer cells. A recent trend of medical imaging analysis is to account for the radiotracer's pharmacokinetic properties at a voxel (three-dimensional-pixel) level to separate the different tissues. These analyses are closely linked to population pharmacokinetic-pharmacodynamic modelling. Kineticists possess the cultural background to improve medical imaging analysis. This article stresses the common points with population pharmacokinetics and highlights the methodological locks that need to be lifted.

  20. Effects of strong CYP2D6 and 3A4 inhibitors, paroxetine and ketoconazole, on the pharmacokinetics and cardiovascular safety of tamsulosin

    NARCIS (Netherlands)

    Troost, Joachim; Tatami, Shinji; Tsuda, Yasuhiro; Mattheus, Michaela; Mehlburger, Ludwig; Wein, Martina; Michel, Martin C.

    2011-01-01

    WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Tamsulosin metabolism involves both CYP2D6 and 3A4. However, data on potential drug-drug interactions between tamsulosin and inhibitors of CYP2D6 and 3A4 are limited and information on potential pharmacodynamic consequences of such pharmacokinetic

  1. Pharmacokinetics and metabolism of (R,R)-methoxyfenoterol in rat.

    Science.gov (United States)

    Siluk, D; Mager, D E; Kim, H S; Wang, Y; Furimsky, A M; Ta, A; Iyer, L V; Green, C E; Wainer, I W

    2010-03-01

    (R,R)-fenoterol (Fen), a beta(2)-adrenoceptor agonist, is under clinical investigation in the treatment of congestive heart disease. The pharmacokinetics and metabolism of the 4-methoxyphenyl derivative of (R,R)-Fen, (R,R)-MFen, have been determined following intravenous and oral administration to the rat and compared with corresponding results obtained with (R,R)-Fen. Results from the study suggest that (R,R)-MFen can offer pharmacokinetic and metabolic advantages in comparison to an earlier (R,R)-Fen. The oral administration revealed that the net exposure of (R,R)-MFen was about three-fold higher than that of (R,R)-Fen (7.2 versus 2.3 min x nmol ml(-1)), while intravenous administration proved that the clearance was significantly reduced, 48 versus 146 ml min(-1) kg(-1), the T(1/2) was significantly longer, 152.9 versus 108.9 min, and the area under the curve (AUC) was significantly increased, 300 versus 119 min x nmol ml(-1). (R,R)-MFen was primarily cleared by glucuronidation associated with significant presystemic glucuronidation of the compound. After intravenous and oral administration of (R,R)-MFen, (R,R)-Fen and (R,R)-Fen-G were detected in the urine samples indicating that (R,R)-MFen was O-demethylated and subsequently conjugated to (R,R)-Fen-G. The total (R,R)-Fen and (R,R)-Fen-G as a percentage of the dose after intravenous administration was 3.6%, while after oral administration was 0.3%, indicating that only a small fraction of the drug escaped presystemic glucuronidation and was available for O-demethylation. The glucuronidation pattern was confirmed by the results from in vitro studies where incubation of (R,R)-MFen with rat hepatocytes produced (R,R)-MFen-G, (R,R)-Fen and (R,R)-Fen-G, while incubation with rat intestinal microsomes only resulted in the formation of (R,R)-MFen-G.

  2. Evaluation of mode equivalence of the MSKCC Bowel Function Instrument, LASA Quality of Life, and Subjective Significance Questionnaire items administered by Web, interactive voice response system (IVRS), and paper.

    Science.gov (United States)

    Bennett, Antonia V; Keenoy, Kathleen; Shouery, Marwan; Basch, Ethan; Temple, Larissa K

    2016-05-01

    To assess the equivalence of patient-reported outcome (PRO) survey responses across Web, interactive voice response system (IVRS), and paper modes of administration. Postoperative colorectal cancer patients with home Web/e-mail and phone were randomly assigned to one of the eight study groups: Groups 1-6 completed the survey via Web, IVRS, and paper, in one of the six possible orders; Groups 7-8 completed the survey twice, either by Web or by IVRS. The 20-item survey, including the MSKCC Bowel Function Instrument (BFI), the LASA Quality of Life (QOL) scale, and the Subjective Significance Questionnaire (SSQ) adapted to bowel function, was completed from home on consecutive days. Mode equivalence was assessed by comparison of mean scores across modes and intraclass correlation coefficients (ICCs) and was compared to the test-retest reliability of Web and IVRS. Of 170 patients, 157 completed at least one survey and were included in analysis. Patients had mean age 56 (SD = 11), 53% were male, 81% white, 53% colon, and 47% rectal cancer; 78% completed all assigned surveys. Mean scores for BFI total score, BFI subscale scores, LASA QOL, and adapted SSQ varied by mode by less than one-third of a score point. ICCs across mode were: BFI total score (Web-paper = 0.96, Web-IVRS = 0.97, paper-IVRS = 0.97); BFI subscales (range = 0.88-0.98); LASA QOL (Web-paper = 0.98, Web-IVRS = 0.78, paper-IVRS = 0.80); and SSQ (Web-paper = 0.92, Web-IVRS = 0.86, paper-IVRS = 0.79). Mode equivalence was demonstrated for the BFI total score, BFI subscales, LASA QOL, and adapted SSQ, supporting the use of multiple modes of PRO data capture in clinical trials.

  3. Pharmacokinetics of neratinib during coadministration with lansoprazole in healthy subjects.

    Science.gov (United States)

    Keyvanjah, Kiana; DiPrimeo, Daniel; Li, Ai; Obaidi, Mohammad; Swearingen, Dennis; Wong, Alvin

    2017-03-01

    To evaluate the effect of lansoprazole, a proton-pump inhibitor, on the absorption, pharmacokinetics, and safety of neratinib, a pan-HER tyrosine kinase inhibitor, in healthy subjects. This was an open-label, two-period, fixed-sequence study. Fifteen healthy adult subjects received a single oral dose of neratinib 240 mg (Period 1), followed by a washout period, then oral lansoprazole 30 mg once daily for 7 days and a single dose of neratinib 240 mg on Day 5 (Period 2). Pharmacokinetic sampling was performed for 72 h following each neratinib dose. Plasma neratinib concentration-time data were analysed using noncompartmental methods. Geometric mean ratios for AUC 0-t , AUC 0-inf , and peak plasma concentrations (C max ) for neratinib plus lansoprazole vs. neratinib were used to assess the magnitude of the drug-drug interaction if the 90% confidence intervals were outside 80.00-125.00%. Neratinib geometric least-squares mean (LSM) C max was reduced from 84.5 ng ml -1 with neratinib alone to 24.5 ng ml -1 with neratinib plus lansoprazole. The extent of exposure to neratinib was also decreased: geometric LSM AUC 0-t was 1478 ng ml -1  h with neratinib vs. 426 ng ml -1  h with neratinib plus lansoprazole, and geometric LSM AUC 0-inf was 1557 ng ml -1  h vs. 542 ng ml -1  h, respectively. Mean t ½ was similar with both treatments (approximately 14 h). Geometric mean ratios 90% confidence intervals for AUC 0-t , AUC 0-inf and C max fell outside the prespecified equivalence range (80.0-125.0%). Treatment-emergent adverse events, all mild, were reported by five (33%) subjects. Coadministration of lansoprazole with neratinib reduced the rate and extent of neratinib exposure in healthy subjects. © 2016 The British Pharmacological Society.

  4. Interethnic differences of PEPT2 (SLC15A2) polymorphism distribution and associations with cephalexin pharmacokinetics in healthy Asian subjects.

    Science.gov (United States)

    Liu, Rui; Tang, Audrey May Yi; Tan, Yen Ling; Limenta, Lie Michael George; Lee, Edmund Jon Deoon

    2009-01-01

    The aims of this study were to characterize the population frequency of PEPT2 (SLC15A2) polymorphic variants in three Asian ethnic populations, namely Chinese, Malay and Asian Indian, and to investigate the associations of ethnicity (Chinese vs. Asian Indian), PEPT2 haplotype and cephalexin pharmacokinetics in healthy Asian subjects. PEPT2 polymorphisms were screened from a cohort of 96 Chinese, 96 Malay and 96 Asian Indian subjects. Cephalexin (1000 mg, orally) pharmacokinetics was characterized in an additional 15 Chinese and 15 Asian Indian healthy subjects. These 30 subjects were subsequently genotyped for their PEPT2 polymorphisms. In total, ten common single nucleotide polymorphisms (SNPs) were detected in the three populations, forming two PEPT2 haplotypes. There were significant ethnic differences in PEPT2 haplotype distribution: the frequencies of the *1 and *2 alleles were 0.307 and 0.693 in the Chinese population, 0.495 and 0.505 in the Malay population and 0.729 and 0.271 in Asian Indian population, respectively. The C (max) of cephalexin was significantly lower in the Chinese (29.80 +/- 4.09 microg ml(-1)) population than in the Asian Indian one (33.29 +/- 4.97 microg ml(-1); P = 0.045). This difference could be explained by the higher average body weight of the Chinese population. There was no other significant difference in cephalexin pharmacokinetics between either ethnic or PEPT2 genotype groups. PEPT2 polymorphism distributions differ significantly between Chinese, Malay and Asian Indian populations. However, cephalexin pharmacokinetics is not meaningfully different between Chinese and Asian Indians. The association between the PEPT2 haplotype and cephalexin pharmacokinetics could not be confirmed, and future studies under better controlled conditions are needed.

  5. Minocycline pharmacokinetics and pharmacodynamics in dogs

    DEFF Research Database (Denmark)

    Maaland, Marit Gaastra; Guardabassi, Luca; Papich, Mark G.

    2014-01-01

    BACKGROUND: Although minocycline is not licensed for use in dogs, this tetracycline has therapeutic potential against meticillin-resistant Staphylococcus pseudintermedius. HYPOTHESIS/OBJECTIVES: The aim of this study was to establish rational dosage recommendations for minocycline use in dogs....... Specific objectives were to generate and analyse minocycline pharmacokinetic (PK) data on plasma and interstitial fluid (ISF) concentrations, plasma protein binding and pharmacodynamic (PD) data on antimicrobial activity against S. pseudintermedius. ANIMALS: Six healthy dogs from a research colony were...... used in this study. METHODS: Dogs were administered 5 mg/kg intravenously and 10 mg/kg orally (p.o.) of minocycline hydrochloride in separate crossover experiments. In vivo drug concentrations in plasma and in ISF collected by ultrafiltration were measured by high-performance liquid chromatography...

  6. Retrospective Evaluation of Milrinone Pharmacokinetics in Children With Kidney Injury.

    Science.gov (United States)

    Gist, Katja M; Mizuno, Tomoyuki; Goldstein, Stuart L; Vinks, Alexander

    2015-12-01

    Milrinone is an inotropic agent with vasodilating properties used in the treatment of ventricular dysfunction. Milrinone is predominantly eliminated by the kidneys and accumulates in the setting of acute kidney injury (AKI). The purpose of this study was to evaluate milrinone pharmacokinetics in children with AKI with or without continuous renal replacement therapy (CRRT). Retrospective collection of milrinone therapeutic drug monitoring data in patients with AKI, including those requiring CRRT, through chart review from January 2008 to March 2014. Pharmacokinetic (PK) data were analyzed by Bayesian estimation using a pediatric population PK model (MW/Pharm). Clearance estimates were allometrically scaled to body weight. Data on 11 patients were available for analysis. Three patients required CRRT. Milrinone concentrations during continuous infusion varied 30-fold and ranged from 44 to 1343 ng/mL. Of the 33 samples obtained in 11 patients, 24 were outside the target range (72.7%), with 16 (48.5%) above and 8 (24.2%) below. Patients with AKI had significantly lower milrinone clearance (4.72 ± 2.26 L/h per 70 kg) compared with published data in patients without AKI. There was large between-patient variability in milrinone clearance (range: 2.91-13.6 L/h per 70 kg). Clearance in patients on CRRT ranged from 2.8 to 7.19 L/h per 70 kg. A significant correlation between milrinone clearance and estimated creatinine clearance was observed (r = 0.70, P = 0.0097). Allometrically scaled milrinone clearance was lower in the youngest patients (younger than 2 years), suggestive of ongoing renal maturation and existing AKI. Pediatric patients with AKI have significantly lower milrinone clearance compared with published data in patients without AKI. Large variability was noted in milrinone concentrations, and they were frequently outside the target range. The large between-patient variability in milrinone concentrations suggests that dosing regimens should be individualized in

  7. Effects of CYP2C19 polymorphism on the pharmacokinetics of lansoprazole and its main metabolites in healthy Chinese subjects.

    Science.gov (United States)

    Zhang, Dan; Wang, Xiaolin; Yang, Man; Wang, Guocai; Liu, Huichen

    2011-06-01

    The aim of the study was to determine the pharmacokinetics of lansoprazole and its main metabolites (5'-hydroxy lansoprazole and lansoprazole sulphone) after administration of enteric-coated tablet in healthy Chinese subjects classified by CYP2C19 genotypes, and evaluate the effects of CYP2C19 genotypes on the pharmacokinetics of the three compounds. A single oral dose of 30 mg lansoprazole was administrated to 24 healthy Chinese male volunteers in different CYP2C19 genotype groups. Blood samples were collected from pre-dose up to 14-h post-dose. Plasma concentration of lansoprazole and its main metabolites were quantified by liquid chromatography-tandem mass spectrometry. CYP2C19 polymorphism had significant effects on the pharmacokinetics of lansoprazole and its main metabolites. The differences in the pharmacokinetics between CYP2C19 extensive metabolizers (Ems) (homo-EMs and hete-EMs) and PMs were more significant for lansoprazole sulphone than for 5'-hydroxy lansoprazole. The results indicate that the monitoring of lansoprazole and its main metabolites in plasma at the time-points in the elimination phase for lansoprazole could reflect the activity of CYP2C19. Simultaneously monitored with lansoprazole sulphone, lansoprazole might be a useful probe drug for CYP2C19.

  8. Pharmacokinetics of topically applied sparfloxacin in rabbits

    Directory of Open Access Journals (Sweden)

    Satia Milan

    2005-01-01

    Full Text Available PURPOSE: Fluoroquinolones are antimicrobial agents that have a broad spectrum of activity and are widely used against many of the ocular pathogens, responsible for conjunctivitis, blepharitis, corneal ulcers etc. The aim of our study was to evaluate the ocular pharmacokinetics of sparfloxacin (0.3% w/v in the aqueous humour of rabbits. MATERIALS AND METHODS: Pharmacokinetics of topically administered sparfloxacin were determined after a single application of 50 µl topically. The aqueous humour samples were collected at 0, 0.25, 0.5, 1, 2, 3, 4, 5 or 6 hours after instillation. High Performance Thin Layer Chromatographic method was used to analyse the drug concentration in the aqueous humour samples. RESULTS: Fifteen minutes after the instillation of 50 µl of sparfloxacin 0.3% solution, the mean concentration in aqueous humour was found to be 1.4 µg/ml, which reaches the peak level of 3.7 µg/ml after 1.3 hours. At 6 hours, the sparfloxacin aqueous levels were 0.562 µg/ml. The clinical efficacy was predicted based on the Maximum Concentration (Cmax: Minimum Inhibitory Concentration (MIC and Area Under the Concentration-time curve (AUC:MIC ratios. CONCLUSION: The sparfloxacin levels in aqueous humour of rabbits are sufficiently high up to the 6 hours after instillation in the conjunctival sac to provide bactericidal effect against most of the ocular pathogens. Both Cmax:MIC and AUC:MIC ratios are high enough to provide bactericidal effect against most of the ocular pathogens. Sparfloxacin (0.3% ophthalmic preparation has excellent penetration through cornea.

  9. Pharmacokinetics of terbutaline in chronic kidney disease.

    Science.gov (United States)

    Bastiansen, Anders; Eggert, Sarah; Pedersen, Erland

    2013-11-01

    In healthy individuals upwards of 90 % of an injected dose of terbutaline is excreted in the urine. The purpose of this study is to determine the pharmacokinetic properties of terbutaline in patients with severe renal impairment as defined by a glomerular filtration rate (GFR) below 30 mL/min. Ten patients were included in the study. GFR was measured with Cr-EDTA clearance. They were given an intravenous injection of 0.500 mg of terbutaline. Blood samples were collected at intervals for 60 h and urine samples were collected for 96 h. The concentration of terbutaline in the blood and in the urine was used to calculate pharmacokinetic parameters. In patients with normal renal function the total clearance of terbutaline is 2.23-3 mL/min/kg. In our population the total clearance of terbutaline was found to be 1.72 (SD: 0.49) mL/min/kg of which approximately 15 % (0.25 mL/min/kg) was renal clearance. We calculated a distribution volume at steady state of 0.74 (SD: 0.22) L/kg with a terminal half-life of 7.93 (SD: 4.06) hours. The mean residence time (MRT) was 8.35 (SD: 4.93) hours. In healthy individuals the excretion of terbutaline is foremost renal but this study shows that severe renal impairment does not lower the total clearance of terbutaline to a degree that might be expected from the Cr-EDTA clearance. However, more research is needed to determine if dosage adjustment is warranted in patients with CKD.

  10. A systems approach for tumor pharmacokinetics.

    Directory of Open Access Journals (Sweden)

    Greg Michael Thurber

    Full Text Available Recent advances in genome inspired target discovery, small molecule screens, development of biological and nanotechnology have led to the introduction of a myriad of new differently sized agents into the clinic. The differences in small and large molecule delivery are becoming increasingly important in combination therapies as well as the use of drugs that modify the physiology of tumors such as anti-angiogenic treatment. The complexity of targeting has led to the development of mathematical models to facilitate understanding, but unfortunately, these studies are often only applicable to a particular molecule, making pharmacokinetic comparisons difficult. Here we develop and describe a framework for categorizing primary pharmacokinetics of drugs in tumors. For modeling purposes, we define drugs not by their mechanism of action but rather their rate-limiting step of delivery. Our simulations account for variations in perfusion, vascularization, interstitial transport, and non-linear local binding and metabolism. Based on a comparison of the fundamental rates determining uptake, drugs were classified into four categories depending on whether uptake is limited by blood flow, extravasation, interstitial diffusion, or local binding and metabolism. Simulations comparing small molecule versus macromolecular drugs show a sharp difference in distribution, which has implications for multi-drug therapies. The tissue-level distribution differs widely in tumors for small molecules versus macromolecular biologic drugs, and this should be considered in the design of agents and treatments. An example using antibodies in mouse xenografts illustrates the different in vivo behavior. This type of transport analysis can be used to aid in model development, experimental data analysis, and imaging and therapeutic agent design.

  11. [Pharmacokinetics of salazosulfapyridine in a hemodialysis patient].

    Science.gov (United States)

    Akiyama, Yuji; Fujimaki, Toshihisa; Sakurai, Yusei

    2003-06-01

    The patient was a 62-year-old female. Total gastrectomy was performed due to gastric ulcer in 1969. She was diagnosed as rheumatoid arthritis (RA) in 1985 and was developed to amyloidosis in 1991. She was started on hemodialysis (HD) for chronic renal failure in 1996. In 1998, her arthralgia was aggravated, and 100 mg/day of bucillamine was administered on the day of HD. Her arthralgia persisted, and switching to salazosulfapyridine (SASP) was considered. As there were no standards and no reports for the use of SASP in HD patients, we examined the pharmacokinetics of SASP and its metabolites, and compared our patient with the results of phase one study in normal subjects in Japan. In this case, the blood concentration of SASP was similar to that in healthy controls after single administration of 500 mg of SASP on the day of non-HD, while the concentration of sulfapyridine (SP) was higher than that in healthy donors. However, the blood concentrations of SASP, SP, and N4-acetyl-SP (AcSP) at 24 hours after administration were similar to those obtained in healthy men. SASP was not dialyzed, while about half of SP and AcSP, were dialyzed. In a five-day consecutive administration study also, the blood concentrations of these compounds on Day 5 were similar to those of phase one study, suggesting no accumulation. No adverse drug reaction was observed. As this case had the past history of total gastrectomy and amyloidosis, it is possible that this result is influenced by the factors. Therefore it is necessary to examine pharmacokinetics of SASP and its metabolites beforehand when administering this agent to other HD/RA patients.

  12. Cefazolin pharmacokinetics in cats under surgical conditions.

    Science.gov (United States)

    Albarellos, Gabriela A; Montoya, Laura; Passini, Sabrina M; Lupi, Martín P; Lorenzini, Paula M; Landoni, María F

    2017-10-01

    Objectives The aim of this study was to determine the plasma pharmacokinetic profile, tissue concentrations and urine elimination of cefazolin in cats under surgical conditions after a single intravenous dose of 20 mg/kg. Methods Intravenous cefazolin (20 mg/kg) was administered to nine young mixed-breed cats 30 mins before they underwent surgical procedures (ovariectomy or orchiectomy). After antibiotic administration, samples from blood, some tissues and urine were taken. Cefazolin concentrations were determined in all biological matrices and pharmacokinetic parameters were estimated. Results Initial plasma concentrations were high (C p(0) , 134.80 ± 40.54 µg/ml), with fast and moderately wide distribution (distribution half-life [t ½(d) ] 0.16 ± 0.15 h; volume of distribution at steady state [V (d[ss]) ] 0.29 ± 0.10 l/kg) and rapid elimination (body clearance [Cl B ], 0.21 ± 0.06 l/h/kg; elimination half-life [t ½ ], 1.18 ± 0.27 h; mean residence time 1.42 ± 0.36 h). Thirty to 60 mins after intravenous administration, cefazolin tissue concentrations ranged from 9.24 µg/ml (subcutaneous tissue) to 26.44 µg/ml (ovary). The tissue/plasma concentration ratio ranged from 0.18 (muscle) to 0.58 (ovary). Cefazolin urine concentrations were high with 84.2% of the administered dose being eliminated in the first 6 h postadministration. Conclusions and relevance Cefazolin plasma concentrations remained above a minimum inhibitory concentration of ⩽2 µg/ml up to 4 h in all the studied cats. This suggests that a single intravenous dose of 20 mg/kg cefazolin would be adequate for perioperative prophylactic use in cats.

  13. Concomitant medication polypharmacy, interactions and imperfect adherence are common in Australian adults on suppressive antiretroviral therapy

    NARCIS (Netherlands)

    Siefried, Krista J; Mao, Limin; Cysique, Lucette A; Rule, John; Giles, Michelle L; Smith, Don E; McMahon, James E.; Read, Tim R; Ooi, Catriona; Tee, Ban K; Bloch, Mark; de Wit, John; Carr, Andrew

    2018-01-01

    OBJECTIVES: We quantified concomitant medication polypharmacy, pharmacokinetic and pharmacodynamic interactions, adverse effects and adherence in Australian adults on effective antiretroviral therapy. DESIGN: Cross-sectional. METHODS: Patients recruited into a nationwide cohort and assessed for

  14. Effects of altered FcγR binding on antibody pharmacokinetics in cynomolgus monkeys

    Science.gov (United States)

    Leabman, Maya K; Meng, Y Gloria; Kelley, Robert F; DeForge, Laura E; Cowan, Kyra J; Iyer, Suhasini

    2013-01-01

    Antibody interactions with Fcγ receptors (FcγRs), like FcγRIIIA, play a critical role in mediating antibody effector functions and thereby contribute significantly to the biologic and therapeutic activity of antibodies. Over the past decade, considerable work has been directed towards production of antibodies with altered binding affinity to FcγRs and evaluation of how the alterations modulate their therapeutic activity. This has been achieved by altering glycosylation status at N297 or by engineering modifications in the crystallizable fragment (Fc) region. While the effects of these modifications on biologic activity and efficacy have been examined, few studies have been conducted to understand their effect on antibody pharmacokinetics (PK). We present here a retrospective analysis in which we characterize the PK of three antibody variants with decreased FcγR binding affinity caused by amino acid substitutions in the Fc region (N297A, N297G, and L234A/L235A) and three antibody variants with increased FcγRIIIA binding affinity caused by afucosylation at N297, and compare their PK to corresponding wild type antibody PK in cynomolgus monkeys. For all antibodies, PK was examined at a dose that was known to be in the linear range. Since production of the N297A and N297G variants in Chinese hamster ovary cells results in aglycosylated antibodies that do not bind to FcγRs, we also examined the effect of expression of an aglycosylated antibody, without sequence change(s), in E. coli. All the variants demonstrated similar PK compared with that of the wild type antibodies, suggesting that, for the six antibodies presented here, altered FcγR binding affinity does not affect PK. PMID:24492343

  15. Drug-drug interactions involving lysosomes: mechanisms and potential clinical implications.

    Science.gov (United States)

    Logan, Randall; Funk, Ryan S; Axcell, Erick; Krise, Jeffrey P

    2012-08-01

    Many commercially available, weakly basic drugs have been shown to be lysosomotropic, meaning they are subject to extensive sequestration in lysosomes through an ion trapping-type mechanism. The extent of lysosomal trapping of a drug is an important therapeutic consideration because it can influence both activity and pharmacokinetic disposition. The administration of certain drugs can alter lysosomes such that their accumulation capacity for co-administered and/or secondarily administered drugs is altered. In this review the authors explore what is known regarding the mechanistic basis for drug-drug interactions involving lysosomes. Specifically, the authors address the influence of drugs on lysosomal pH, volume and lipid processing. Many drugs are known to extensively accumulate in lysosomes and significantly alter their structure and function; however, the therapeutic and toxicological implications of this remain controversial. The authors propose that drug-drug interactions involving lysosomes represent an important potential source of variability in drug activity and pharmacokinetics. Most evaluations of drug-drug interactions involving lysosomes have been performed in cultured cells and isolated tissues. More comprehensive in vivo evaluations are needed to fully explore the impact of this drug-drug interaction pathway on therapeutic outcomes.

  16. Effect of Smoking on Pharmacokinetics of Clopidogrel, an ...

    African Journals Online (AJOL)

    ... in patients undergoing PCI. Keywords: Antiplatelet, Clopidogrel, Pharmacokinetics, Smoking, Cigarette ..... regimen of choice to prevent thrombotic complications. [2,16]. ... either the parent drug [19] or the carboxylic acid metabolite as an ...

  17. Pharmacokinetics of Rhodamine 110 and Its Organ Distribution in Rats.

    Science.gov (United States)

    Jiang, Shiau-Han; Cheng, Yung-Yi; Huo, Teh-Ia; Tsai, Tung-Hu

    2017-09-06

    Rhodamine dyes have been banned as food additives due to their potential tumorigenicity. Rhodamine 110 is illegal as a food additive, although its pharmacokinetics have not been characterized, and no accurate bioanalytical methods are available to quantify rhodamine 110. The aim of this study was to develop and validate a fast, stable, and sensitive method to quantify rhodamine 110 using high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) to assess its pharmacokinetics and organ distribution in awake rats. Rhodamine 110 exhibited linear pharmacokinetics and slow elimination after oral administration. Furthermore, its oral bioavailability was approximately 34-35%. The distribution in the liver and kidney suggests that these organs are primarily responsible for rhodamine 110 metabolism and elimination. Our investigation describes the pharmacokinetics and a quantification method for rhodamine 110, improving our understanding of the food safety of rhodamine dyes.

  18. A Comparative Study of the Pharmacokinetics of Conventional and ...

    African Journals Online (AJOL)

    Erah

    Purpose: To examine the pharmacokinetics of a formulated aceclofenac sustained release ... over 24 h and analyzed by high performance liquid chromatography (HPLC). .... The response factor .... slower drug disposition and prolonged effect.

  19. Pharmacokinetically guided dosing of (high-dose) chemotherapeutic agents

    NARCIS (Netherlands)

    Attema-de Jonge, M.E. (Milly Ellen)

    2004-01-01

    Due to variation in drug distribution, metabolism and elimination processes between patients, systemic exposure to chemotherapeutic agents may be highly variable from patient to patient after administration of similar doses. This pharmacokinetic variability may explain in part the large variability

  20. Pharmacokinetics of 2 Formulations of Transdermal Fentanyl in Cynomolgus Macaques (Macaca fascicularis)

    Science.gov (United States)

    Carlson, Amy M; Kelly, Richard; Fetterer, David P; Rico, Pedro J; Bailey, Emily J

    2016-01-01

    Fentanyl is a μ-opioid agonist that often is used as the analgesic component for balanced anesthesia in both human and veterinary patients. Minimal information has been published regarding appropriate dosing, and the pharmacokinetics of fentanyl are unknown in NHP. The pharmacokinetic properties of 2 transdermal fentanyl delivery methods, a solution (2.6 and 1.95 mg/kg) and a patch (25 µg/h), were determined when applied topically to the dorsal scapular area of cynomolgus macaques (Macaca fascicularis). Serum fentanyl concentrations were analyzed by using liquid chromatography–mass spectrometry. Compared with the patch, the transdermal fentanyl solution generated higher drug concentrations over longer time. Adverse reactions occurred in the macaques that received the transdermal fentanyl solution at 2.6 mg/kg. Both preparations showed significant interanimal variability in the maximal serum drug levels, time to achieve maximal fentanyl levels, elimination half-life, and AUC values. Both the maximal concentration and the time at which this concentration occurred were increased in macaques compared with most other species after application of the transdermal fentanyl patch and compared with dogs after application of the transdermal fentanyl solution. The pharmacokinetic properties of transdermal fentanyl in macaques are markedly different from those in other veterinary species and preclude its use as a long-acting analgesic drug in NHP. PMID:27423151

  1. Comparative Pharmacokinetics and Allometric Scaling of Carboplatin in Different Avian Species.

    Directory of Open Access Journals (Sweden)

    Gunther Antonissen

    Full Text Available The use of chemotherapeutics as a possible treatment strategy in avian oncology is steadily increasing over the last years. Despite this, literature reports regarding dosing strategies and pharmacokinetic behaviour of chemotherapeutics in avian species are lacking. The aim of the present study was to investigate the pharmacokinetics of carboplatin in a representative species of the order of Galliformes, Anseriformes, Columbiformes and Psittaciformes. Eight chickens, ducks and pigeons and twenty-eight parakeets were administered carboplatin intravenously (5 mg/kg body weight. A specific and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of the free carboplatin in plasma of the four birds species (limit of quantification: 20 ng/mL for chicken and duck, 50 ng/mL for pigeon and 100 ng/mL for parakeets. Non-compartmental pharmacokinetic analysis and allometric scaling demonstrated a significant correlation (R² = 0.9769 between body weight (BW and elimination half-life (T1/2el. T1/2el ranged from 0.41 h in parakeets (BW: 61 ± 8 g to 1.16 h chickens (BW: 1909 ± 619 g. T1/2el is a good parameter for dose optimization of carboplatin in other avian species, since also the previously reported T1/2el in cockatoos (average BW: 769 ± 68 g of 1.00 h corresponds to the results obtained in the present study.

  2. Comparative pharmacokinetics of acetyl salicylic acid and its metabolites in children suffering from autoimmune diseases.

    Science.gov (United States)

    Juárez Olguín, Hugo; Flores Pérez, Janett; Lares Asseff, Ismael; Loredo Abdalá, Arturo; Carbajal Rodríguez, Luis

    2004-01-01

    The aim of the present study was to compare the effect produced by juvenile rheumatoid arthritis (JRA) or rheumatic fever (RF) on the pharmacokinetics of acetyl salicylic acid (ASA) and its metabolites in children with autoimmune diseases (AD). A prospective, open labelled study was performed in 17 children with JRA and 17 with RF who received a single dose of 25 mg ASA/kg orally. The pharmacokinetics of ASA and its metabolites were determined. The blood and urine levels of each salicylate collected during 24 h were measured by HPLC. A group of 15 healthy teenage volunteers was included as a control group. The maximum plasma concentration, half-life time, area under the curve and the amount of salicylates excreted were statistically different between the JRA and the RF groups, as well as between the RF group and the controls, however, there were no significant differences between the JRA group and the controls. Dosage schemes must be adjusted for JRA patients, since the half life in these patients is longer than in RF patients. However, due to ample variability of pharmacokinetic parameters it is recommended that dose schemes are individualized on the type of autoimmune disease considered. Copyright 2004 John Wiley & Sons, Ltd.

  3. Atorvastatin calcium loaded chitosan nanoparticles: in vitro evaluation and in vivo pharmacokinetic studies in rabbits

    Directory of Open Access Journals (Sweden)

    Abdul Baquee Ahmed

    2015-06-01

    Full Text Available In this study, we prepared atorvastatin calcium (AVST loaded chitosan nanoparticles to improve the oral bioavailability of the drug. Nanoparticles were prepared by solvent evaporation technique and evaluated for its particle size, entrapment efficiency, zeta potential, in vitro release and surface morphology by scanning electron microscopy (SEM. In addition, the pharmacokinetics of AVST from the optimized formulation (FT5 was compared with marketed immediate release formulation (Atorva(r in rabbits. Particle size of prepared nanoparticles was ranged between 179.3 ± 7.12 to 256.8 ± 8.24 nm with a low polydispersity index (PI value. Zeta potential study showed that the particles are stable with positive values between 13.03 ± 0.32 to 46.90 ± 0.49 mV. FT-IR studies confirmed the absence of incompatibility of AVST with excipient used in the formulations. In vitro release study showed that the drug release was sustained for 48 h. Results of pharmacokinetics study showed significant changes in the pharmacokinetic parameter (2.2 fold increase in AUC of the optimized formulation as compared to marketed formulation (Atorva(r. Thus, the developed nanoparticles evidenced the improvement of oral bioavailability of AVST in rabbit model.

  4. Biodegradable nanoparticles for improved kidney bioavailability of rhein: preparation, characterization, plasma, and kidney pharmacokinetics.

    Science.gov (United States)

    Wei, Yinghui; Luo, Xiaoting; Guan, Jiani; Ma, Jianping; Zhong, Yicong; Luo, Jingwen; Li, Fanzhu

    2017-11-01

    The aim of this work is to develop biodegradable nanoparticles for improved kidney bioavailability of rhein (RH). RH-loaded nanoparticles were prepared using an emulsification solvent evaporation method and fully characterized by several techniques. Kidney pharmacokinetics was assessed by implanting a microdialysis probe in rat's kidney cortex. Blood samples were simultaneously collected (via femoral artery) for assessing plasma pharmacokinetics. Optimized nanoparticles were small, with a mean particle size of 132.6 ± 5.95 nm, and homogeneously dispersed. The charge on the particles was nearly zero, the encapsulation efficiency was 62.71 ± 3.02%, and the drug loading was 1.56 ± 0.15%. In vitro release of RH from the nanoparticles showed an initial burst release followed by a sustained release. Plasma and kidney pharmacokinetics showed that encapsulation of RH into nanoparticles significantly increased its kidney bioavailability (AUC kidney /AUC plasma  = 0.586 ± 0.072), clearly indicating that nanoparticles are a promising strategy for kidney drug delivery.

  5. Steady-state pharmacokinetics and pharmacodynamics of cysteamine bitartrate in paediatric nephropathic cystinosis patients.

    Science.gov (United States)

    Belldina, Eric B; Huang, Mei Y; Schneider, Jerry A; Brundage, Richard C; Tracy, Timothy S

    2003-11-01

    Cysteamine is used to reduce tissue cystine content in patients suffering from nephropathic cystinosis. The objectives of the current study were to investigate pharmacokinetics and pharmacodynamics of cysteamine bitartrate in children and young adults with nephropathic cystinosis. Cysteamine bitartrate was administered to 11 cystinosis patients at their regular dose level in a single-dose, open-label, steady-state study. Blood samples were collected and analysed for plasma cysteamine and white blood cell cystine content and pharmacokinetic and pharmacodynamic parameters estimated by NONMEM analysis using a linked pharmacokinetic-pharmacodynamic model. Cysteamine was rapidly cleared from the plasma (mean CL/F = 32.3 ml min(-1) kg(-1), range = 17.3-52.2), appeared to be extensively distributed (mean Vss/F = 15.1 l, range 2.7-32.3) and exhibited a mean Tmax of 1.4 h. White blood cell cystine content post-dosing was significantly decreased compared with pre- and post-dose values (average decrement approximately 47%). A counter-clockwise hysteresis was noted in all patients, suggestive of a lag time (mean Tlag = 0.44 h, range 0.22-0.92) between drug concentration and effect. The results of this study establish that cysteamine is rapidly cleared from the plasma but that an every 6 h dosing interval adequately maintains white blood cell cystine content below the target of 1 nmol cystine per mg protein.

  6. ZD0473 pharmacokinetics in Japanese patients: a Phase I dose-escalation study.

    Science.gov (United States)

    Murakami, H; Tamura, T; Yamada, Y; Yamamoto, N; Ueda, Y; Shimoyama, T; Saijo, N

    2002-12-01

    ZD0473 is new platinum agent that was rationally designed to circumvent platinum resistance and reduce the potential for nephro-and neurotoxicity. This Phase I dose-escalating study investigated the pharmacokinetics, tolerability and efficacy of ZD0473 in Japanese patients with solid, refractory tumours. ZD0473 was administered as a 1-h intravenous infusion every 3 weeks. Nine patients received a total of 16 cycles of ZD0473 (median 1 cycle/patient), with 3 patients treated at each of 3 doses (60, 90, 120 mg/m2). The maximum plasma concentration (C(max)) and the area under the concentration-time curve to infinity (AUC(0-infinity)) increased with dose in a linear fashion for both total platinum and ZD0473 in plasma ultrafiltrate, suggesting that the pharmacokinetics of ZD0473 are linear. Haematological and non-haematological toxicities such as nausea and vomiting were mild (grade 1 or 2) and transient. No clinically significant nephro-, oto- or neurotoxicity was observed. Dose-limiting toxicity (DLT) was not observed and the maximum tolerated dose (MTD) was not identified. ZD0473 treatment showed evidence of disease stabilisation in 3 patients (33%). In conclusion, ZD0473 appears to have linear pharmacokinetics, and an acceptable tolerability profile at doses up to 120 mg/m2 in Japanese patients with refractory solid malignancies. Following evaluation of the data from all the Western trials, the ZD0473 development programme changed and this Japanese trial was stopped.

  7. Pharmacokinetics of nicotine following the controlled use of a prototype novel tobacco vapor product.

    Science.gov (United States)

    Yuki, Dai; Sakaguchi, Chikako; Kikuchi, Akira; Futamura, Yasuyuki

    2017-07-01

    The objective of this clinical study was to investigate the pharmacokinetics of nicotine following the use of a prototype novel tobacco vapor (PNTV) product in comparison to a conventional cigarette (CC1). The study was conducted in Japanese healthy adult male smokers, using an open-label, randomized, two-period crossover design, to assess the pharmacokinetics of nicotine after controlled use of a PNTV product or CC1. During the study period, blood samples were drawn from subjects for the measurement of plasma nicotine concentrations and nicotine intake was estimated from the mouth level exposure (MLE). The C max and AUC last following the use of PNTV product were 45.7% and 68.3%, respectively, of those obtained with CC1 and there were no significant differences in the tmax and t 1/2 between PNTV product and CC1. The estimated MLE following the use of PNTV product was approximately two-thirds of that obtained following the smoking of CC1, but the relative bioavailability of PNTV product to CC1 was approximately 104%. The differences in C max and AUC last between PNTV product and CC1 therefore are explained by differences in nicotine intake. These results suggest that the PNTV product shows a similar pharmacokinetic profile to CC1, while delivering less nicotine following controlled use. Copyright © 2017 Japan Tobacco Inc. Published by Elsevier Inc. All rights reserved.

  8. Pharmacokinetic study of benfotiamine and the bioavailability assessment compared to thiamine hydrochloride.

    Science.gov (United States)

    Xie, Feifan; Cheng, Zeneng; Li, Sanwang; Liu, Xingling; Guo, Xin; Yu, Peng; Gu, Zhenkun

    2014-06-01

    Benfotiamine is a lipid-soluble thiamine precursor which can transform to thiamine in vivo and subsequently be metabolized to thiamine monophosphate (TMP) and thiamine diphosphate (TDP). This study investigated the pharmacokinetic profiles of thiamine and its phosphorylated metabolites after single- and multiple-dose administration of benfotiamine in healthy Chinese volunteers, and assessed the bioavailability of orally benfotiamine administration compared to thiamine hydrochloride. In addition, concentration of hippuric acid in urine which is produced in the transformation process of benfotiamine was determined. The results showed that thiamine and its phosphorylated metabolites exhibited different pharmacokinetic characteristics in plasma, blood and erythrocyte, and one-compartment model provided the best fit for pharmacokinetic profiles of thiamine. The transformation process of benfotiamine to thiamine produced large amount of hippuric acid. No accumulation of hippuric acid was observed after multiple-dose of benfotiamine. Compared to thiamine hydrochloride, the bioavailability of thiamine in plasma and TDP in erythrocyte after oral administration of benfotiamine were 1147.3 ± 490.3% and 195.8 ± 33.8%, respectively. The absorption rate and extent of benfotiamine systemic availability of thiamine were significantly increased indicating higher bioavailability of thiamine from oral dose of benfotiamine compared to oral dose of thiamine hydrochloride. © 2014, The American College of Clinical Pharmacology.

  9. Comparison of Dapivirine Vaginal Gel and Film Formulation Pharmacokinetics and Pharmacodynamics (FAME 02B).

    Science.gov (United States)

    Robinson, Jennifer A; Marzinke, Mark A; Bakshi, Rahul P; Fuchs, Edward J; Radebaugh, Christine L; Aung, Wutyi; Spiegel, Hans M L; Coleman, Jenell S; Rohan, Lisa C; Hendrix, Craig W

    2017-04-01

    While preexposure prophylaxis with oral tenofovir/emtricitabine reduces HIV acquisition rates, poor adherence to and acceptability of vaginal gels and the potential for evolving drug resistance have led to development of vaginal film formulations and other antiretroviral drugs, respectively, including the non-nucleoside reverse transcriptase inhibitor dapivirine. In this two-arm crossover study of a novel fast-dissolving dapivirine film and a previously studied semisolid dapivirine gel, 10 healthy women received a single 1.25 mg vaginal dose of each study product; one withdrew after the first dose. Clinical, pharmacokinetic, and antiviral pharmacodynamic assessments (ex vivo HIV-BaL challenge of tissue explants) were performed over 168 h postdose. Six of ten participants experienced mild to moderate adverse effects, similar between products, with no severe adverse events or adverse events attributed to study products. There were no statistically significant differences in plasma, cervicovaginal fluid (CVF), or cervical tissue dapivirine concentrations between the gel and film (all p > .05). CVF dapivirine concentrations were 1.5 and 6 log 10 greater than tissue and plasma concentrati