WorldWideScience

Sample records for bioavailability

  1. Folate bioavailability.

    Science.gov (United States)

    McNulty, Helene; Pentieva, Kristina

    2004-11-01

    The achievement of optimal folate status to prevent neural-tube defects, and possibly other diseases, is hindered by the well-recognised incomplete bioavailability of the natural folates found in foods compared with the synthetic vitamin, folic acid. Folate bioavailability from different foods is considered to be dependent on a number of factors, including the food matrix, the intestinal deconjugation of polyglutamyl folates, the instability of certain labile folates during digestion and the presence of certain dietary constituents that may enhance folate stability during digestion. There is conflicting evidence as to whether the extent of conjugation of polyglutamyl folate (in the absence of specific inhibitors of deconjugation in certain foods) is a limiting factor in folate bioavailability. Estimates of the extent of lower bioavailability of food folates compared with folic acid (relative bioavailability) show great variation, ranging anywhere between 10 and 98%, depending on the methodological approach used. The lack of accurate data on folate bioavailability from natural food sources is of particular concern in those countries in which there is no mandatory folic acid fortification, and therefore a greater reliance on natural food folates as a means to optimise status. Apart from the incomplete bioavailability of food folates, the poor stability of folates in foods (particularly green vegetables) under typical conditions of cooking can substantially reduce the amount of vitamin ingested and thereby be an additional factor limiting the ability of food folates to enhance folate status. A recent workshop convened by the Food Standards Agency concluded that gaining a better understanding of folate bioavailability in representative human diets is a high priority for future research.

  2. Methotrexate bioavailability

    NARCIS (Netherlands)

    van Roon, E. N.; van de Laar, M. A. F. J.

    2010-01-01

    The clinical relevance of the concept of bioavailability rests on two main principles. First, that measurement of the active component at the site of action is generally not possible and, secondly, that a relationship exists between on the one hand efficacy and/or safely and on the other hand concen

  3. Human Folate Bioavailability

    Directory of Open Access Journals (Sweden)

    Cornelia M. Witthoft

    2011-04-01

    Full Text Available The vitamin folate is recognized as beneficial health-wise in the prevention of neural tube defects, anemia, cardiovascular diseases, poor cognitive performance, and some forms of cancer. However, suboptimal dietary folate intake has been reported in a number of countries. Several national health authorities have therefore introduced mandatory food fortification with synthetic folic acid, which is considered a convenient fortificant, being cost-efficient in production, more stable than natural food folate, and superior in terms of bioavailability and bioefficacy. Other countries have decided against fortification due to the ambiguous role of synthetic folic acid regarding promotion of subclinical cancers and other adverse health effects. This paper reviews recent studies on folate bioavailability after intervention with folate from food. Our conclusions were that limited folate bioavailability data are available for vegetables, fruits, cereal products, and fortified foods, and that it is difficult to evaluate the bioavailability of food folate or whether intervention with food folate improves folate status. We recommend revising the classical approach of using folic acid as a reference dose for estimating the plasma kinetics and relative bioavailability of food folate.

  4. Bioavailability of Tea Polyphenols

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Tea is a pleasant, popular and safe beverage. Tea provides a dietary source of bioactive components to help humans reduce a wide variety of cancer risks and chronic diseases. The antioxidative activity of green tea-derived polypbenols known as catchins has been extensively studied. The reducfive effect is a synergistic action between EGCG,EGC, ECG, EC, pheophytins a and b, and other components in tealeaves, which are more bioavailable for human body.Green tea has a higher content of catechins than black tea. Green tea extract with hot water has high potential and more efficiencytoreducecancerriskthananyotherteaproductsorpureEGCG. Protein, iron, andotherfoodcomponentsmay interfere with the bioavailability of tea polyphenols. Drinkinggreentea (orpolyphenol-rich tea extract ) also enhances the cancer-preventive activity of some cancer-fighting medication such as Sulindac and Tamoxifen. Further studies are required to determine the bioavailability of green tea and cancer-preventive functionality.

  5. Bioavailability: implications for science/cleanup policy

    Energy Technology Data Exchange (ETDEWEB)

    Denit, Jeffery; Planicka, J. Gregory

    1998-12-01

    This paper examines the role of bioavailability in risk assessment and cleanup decisions. Bioavailability refers to how chemicals ''behave'' and their ''availability'' to interact with living organisms. Bioavailability has significant implications for exposure risks, cleanup goals, and site costs. Risk to human health and the environment is directly tied to the bioavailability of the chemicals of concern.

  6. Bioavailability of Promethazine during Spaceflight

    Science.gov (United States)

    Boyd, Jason L.; Wang, Zuwei; Putcha, Lakshmi

    2009-01-01

    Promethazine (PMZ) is the choice anti-motion sickness medication for treating space motion sickness (SMS) during flight. The side effects associated with PMZ include dizziness, drowsiness, sedation, and impaired psychomotor performance which could impact crew performance and mission operations. Early anecdotal reports from crewmembers indicate that these central nervous system side effects of PMZ are absent or greatly attenuated in microgravity, potentially due to changes in pharmacokinetics (PK) and pharmacodynamics in microgravity. These changes could also affect the therapeutic effectiveness of drugs in general and PMZ, in particular. In this investigation, we examined bioavailability and associated pharmacokinetics of PMZ in astronauts during and after space flight. Methods. Nine astronauts received, per their preference, PMZ (25 or 50 mg as intramuscular injection, oral tablet, or rectal suppository) on flight day one for the treatment of SMS and subsequently collected saliva samples and completed sleepiness scores for 72 h post dose. Thirty days after the astronauts returned to Earth, they repeated the protocol. Bioavailability and PK parameters were calculated and compared between flight and ground. Results. Maximum concentration (Cmax) was lower and time to reach Cmax (tmax) was longer in flight than on the ground. Area under the curve (AUC), a measure of bioavailability, was lower and biological half-life (t1/2) was longer in flight than on the ground. Conclusion. Results indicate that bioavailability of PMZ is reduced during spaceflight. Number of samples, sampling method, and sampling schedule significantly affected PK parameter estimates.

  7. Bioavailability & Bioequivalence Studies ? Pharmaceutical Importance

    OpenAIRE

    Pratibha Muntha

    2015-01-01

    Pharmacokinetics has now emerged as an important part of drug development especially in the development of new drugs. The combined studies of Pharmacodynamics and pharmacokinetics present a thorough understanding on how the drug affects the body and how the body affects the drug.Bioavailability is the study of the rate and extent to which the active ingredient is absorbed from a dosage form and it is available at the required action site. Bioequivalence is that the...

  8. Nitric oxide bioavailability in malaria.

    Science.gov (United States)

    Sobolewski, Peter; Gramaglia, Irene; Frangos, John; Intaglietta, Marcos; van der Heyde, Henri C

    2005-09-01

    Rational development of adjunct or anti-disease therapy for severe Plasmodium falciparum malaria requires cellular and molecular definition of malarial pathogenesis. Nitric oxide (NO) is a potential target for such therapy but its role during malaria is controversial. It has been proposed that NO is produced at high levels to kill Plasmodium parasites, although the unfortunate consequence of elevated NO levels might be impaired neuronal signaling, oxidant damage and red blood cell damage that leads to anemia. In this case, inhibitors of NO production or NO scavengers might be an effective adjunct therapy. However, increasing amounts of evidence support the alternate hypothesis that NO production is limited during malaria. Furthermore, the well-documented NO scavenging by cell-free plasma hemoglobin and superoxide, the levels of which are elevated during malaria, has not been considered. Low NO bioavailability in the vasculature during malaria might contribute to pathologic activation of the immune system, the endothelium and the coagulation system: factors required for malarial pathogenesis. Therefore, restoring NO bioavailability might represent an effective anti-disease therapy.

  9. Bioavailability of xenobiotics in the soil environment.

    Science.gov (United States)

    Katayama, Arata; Bhula, Raj; Burns, G Richard; Carazo, Elizabeth; Felsot, Allan; Hamilton, Denis; Harris, Caroline; Kim, Yong-Hwa; Kleter, Gijs; Koedel, Werner; Linders, Jan; Peijnenburg, J G M Willie; Sabljic, Aleksandar; Stephenson, R Gerald; Racke, D Kenneth; Rubin, Baruch; Tanaka, Keiji; Unsworth, John; Wauchope, R Donald

    2010-01-01

    It is often presumed that all chemicals in soil are available to microorganisms, plant roots, and soil fauna via dermal exposure. Subsequent bioaccumulation through the food chain may then result in exposure to higher organisms. Using the presumption of total availability, national governments reduce environmental threshold levels of regulated chemicals by increasing guideline safety margins. However, evidence shows that chemical residues in the soil environment are not always bioavailable. Hence, actual chemical exposure levels of biota are much less than concentrations present in soil would suggest. Because "bioavailability" conveys meaning that combines implications of chemical sol persistency, efficacy, and toxicity, insights on the magnitude of a chemicals soil bioavailability is valuable. however, soil bioavailability of chemicals is a complex topic, and is affected by chemical properties, soil properties, species exposed, climate, and interaction processes. In this review, the state-of-art scientific basis for bioavailability is addressed. Key points covered include: definition, factors affecting bioavailability, equations governing key transport and distributive kinetics, and primary methods for estimating bioavailability. Primary transport mechanisms in living organisms, critical to an understanding of bioavailability, also presage the review. Transport of lipophilic chemicals occurs mainly by passive diffusion for all microorganisms, plants, and soil fauna. Therefore, the distribution of a chemical between organisms and soil (bioavailable proportion) follows partition equilibrium theory. However, a chemical's bioavailability does not always follow partition equilibrium theory because of other interactions with soil, such as soil sorption, hysteretic desorption, effects of surfactants in pore water, formation of "bound residue", etc. Bioassays for estimating chemical bioavailability have been introduced with several targeted endpoints: microbial

  10. Bioavailability of voriconazole in hospitalised patients

    NARCIS (Netherlands)

    Veringa, Anette; Geling, Sanne; Span, Lambert F R; Vermeulen, Karin M; Zijlstra, Jan G; van der Werf, Tjip S; Kosterink, Jos G W; Alffenaar, Jan-Willem C

    2016-01-01

    An important element in antimicrobial stewardship programmes is early switch from intravenous (i.v.) to oral antimicrobial treatment, especially for highly bioavailable drugs. The antifungal agent voriconazole is available both in i.v. and oral formulations and bioavailability is estimated to be >90

  11. The Nutraceutical Bioavailability Classification Scheme: Classifying Nutraceuticals According to Factors Limiting their Oral Bioavailability.

    Science.gov (United States)

    McClements, David Julian; Li, Fang; Xiao, Hang

    2015-01-01

    The oral bioavailability of a health-promoting dietary component (nutraceutical) may be limited by various physicochemical and physiological phenomena: liberation from food matrices, solubility in gastrointestinal fluids, interaction with gastrointestinal components, chemical degradation or metabolism, and epithelium cell permeability. Nutraceutical bioavailability can therefore be improved by designing food matrices that control their bioaccessibility (B*), absorption (A*), and transformation (T*) within the gastrointestinal tract (GIT). This article reviews the major factors influencing the gastrointestinal fate of nutraceuticals, and then uses this information to develop a new scheme to classify the major factors limiting nutraceutical bioavailability: the nutraceutical bioavailability classification scheme (NuBACS). This new scheme is analogous to the biopharmaceutical classification scheme (BCS) used by the pharmaceutical industry to classify drug bioavailability, but it contains additional factors important for understanding nutraceutical bioavailability in foods. The article also highlights potential strategies for increasing the oral bioavailability of nutraceuticals based on their NuBACS designation (B*A*T*).

  12. Bioavailability of Metals in Contaminated Sediments

    Directory of Open Access Journals (Sweden)

    Paller M. H.

    2013-04-01

    Full Text Available Bioavailability controls the transfer of metals from sediments to ecological receptors and humans. It can rarely be predicted from total metal concentrations because it is affected by metal geochemistry in sediments as well as the biochemistry, physiology, and behavior of benthic organisms. There is no single approach for including bioavailability in risk assessments because of variability in site specific conditions and the difficulty of validating methods. Acid-volatile sulfide and simultaneously extracted metals are useful in predicting bioavailability in anoxic sediments containing sulfides that react to form insoluble metal complexes. This method can be improved by adjusting for organic carbon and other ligands that also bind free metals. Site-specific desorption Kd values calculated by sequential extraction methods can be useful in predicting bioavailable metal fractions in oxic and anoxic sediments. A modified desorption distribution coefficient (Kdg can be calculated by extraction with the digestive gut fluids of sediment feeding organisms to account for the effects of ingestion on metal release from sediments. Recently developed in situ measurement technologies can accumulate dissolved metals in a controlled fashion that may correspond with bioavailable metal fractions in sediment. Successful evaluation of bioavailability requires the selection of methods suitable for the organisms and sediment environments under consideration. A weight-of-evidence approach that incorporates multiple lines of evidence can help address uncertainties and increase the likelihood of incorporating bioavailability into remedial decisions.

  13. [Bioavailability of drugs--concepts and problems].

    Science.gov (United States)

    Bekemeier, H; Hirschelmann, R

    1984-01-01

    The development of the concept of bioavailability is dealt with on the basis of definitions published in the literature. In this connexion, the often extent divergency between the definition and the determination of bioavailability in practice is indicated. Furthermore, the bioavailability is differentiated from the amount of absorption. With regard to the inclusion of the levels of in vitro liberation, liberation in the body and absorption achieved, the frequently stated use of one and the same term for different contents gives rise to a disentanglement of the terms. Perspectively, the inclusion of animal experimentation in pharmacokinetic-biopharmaceutical investigations is insisted on.

  14. 21 CFR 320.38 - Retention of bioavailability samples.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Retention of bioavailability samples. 320.38... (CONTINUED) DRUGS FOR HUMAN USE BIOAVAILABILITY AND BIOEQUIVALENCE REQUIREMENTS Procedures for Determining the Bioavailability or Bioequivalence of Drug Products § 320.38 Retention of bioavailability...

  15. Unraveling Anthocyanin Bioavailability for Human Health.

    Science.gov (United States)

    Lila, Mary Ann; Burton-Freeman, Britt; Grace, Mary; Kalt, Wilhelmina

    2016-01-01

    This review considers the bioavailability of health-protective anthocyanin pigments from foods, in light of the multiple molecular structures and complicated traffic patterns taken by anthocyanins both as flavonoid metabolites and as phenolic acid metabolites within the body. Anthocyanins have generally been considered to have notoriously poor bioavailability, based on the very low levels typically detected in routine human blood draws after ingestion. Although some investigations have assessed anthocyanin bioavailability solely based on the measurement of parent anthocyanins or phenolic acid breakdown products, more recent research has increasingly revealed the presence, qualitative diversity, relatively high concentrations, and tenacity of molecular intermediates of anthocyanins that retain the unique flavonoid C6-C3-C6 backbone structure. We argue that the persistence of anthocyanin metabolites suggests enterohepatic recycling, leading to prolonged residence time, and supports the notion that anthocyanins are far more bioavailable than previously suggested.

  16. Bioavailability of cefuroxime axetil formulations.

    Science.gov (United States)

    Donn, K H; James, N C; Powell, J R

    1994-06-01

    Cefuroxime axetil tablets have proved effective for the treatment of a variety of community-acquired infections. A suspension formulation has been developed for use in children. Two studies have been conducted to determine if the cefuroxime axetil formulations are bioequivalent. In the initial randomized, two-period crossover study, 24 healthy men received 250-mg doses of suspension and tablet formulations of cefuroxime axetil every 12 h after eating for seven doses. Each treatment period was separated by 4 days. Comparisons of serum and urine pharmacokinetic parameters indicated that the suspension and tablet formulations of cefuroxime axetil are not bioequivalent. Following the initial bioequivalency study, 0.1 % sodium lauryl sulfate (SLS) was added to the suspension to assure the homogeneity of the granules during the manufacturing process. In the subsequent randomized, three-period crossover study, 24 healthy men received single 250-mg doses of three cefuroxime axetil formulations: suspension without SLS, suspension with SLS, and tablet. Again each treatment period was separated by 4 days. Pharmacokinetic analyses demonstrated that while the suspension with SLS and suspension without SLS are bioequivalent, bioequivalence between the suspension with SLS and the tablet was not observed. Thus, the addition of the SLS surfactant to the suspension did not alter the bioavailability of the formulation.

  17. Bioavailability and variability of biphasic insulin mixtures

    DEFF Research Database (Denmark)

    Søeborg, Tue; Rasmussen, Christian Hove; Mosekilde, Erik

    2012-01-01

    , the absorption kinetics for mixtures of insulins is described. This requires that the bioavailability of the different insulins is considered. A short review of insulin bioavailability and a description of the subcutaneous depot thus precede the presentation of possible mechanisms associated with subcutaneous...... mixtures. The results can be used in both the development of novel insulin products and in the planning of the treatment of insulin dependent diabetic patients....

  18. Iron bioavailability from commercially available iron supplements

    OpenAIRE

    2015-01-01

    Purpose Iron deficiency anaemia (IDA) is a global public health problem. Treatment with the standard of care ferrous iron salts may be poorly tolerated, leading to non-compliance and ineffective correction of IDA. Employing supplements with higher bioavailability might permit lower doses of iron to be used with fewer side effects, thus improving treatment efficacy. Here, we compared the iron bioavailability of ferrous sulphate tablets with alternative commercial iron products, including th...

  19. Bioavailability and Bioequivalence in Drug Development

    OpenAIRE

    Chow, Shein-Chung

    2014-01-01

    Bioavailability is referred to as the extent and rate to which the active drug ingredient or active moiety from the drug product is absorbed and becomes available at the site of drug action. The relative bioavailability in terms of the rate and extent of drug absorption is considered predictive of clinical outcomes. In 1984, the United States Food and Drug Administration (FDA) was authorized to approve generic drug products under the Drug Price Competition and Patent Term Restoration Act base...

  20. Bioavailability enhancers of herbal origin: an overview.

    Science.gov (United States)

    Kesarwani, Kritika; Gupta, Rajiv; Mukerjee, Alok

    2013-04-01

    Recently, the use of herbal medicines has been increased all over the world due to their therapeutic effects and fewer adverse effects as compared to the modern medicines. However, many herbal drugs and herbal extracts despite of their impressive in-vitro findings demonstrates less or negligible in-vivo activity due to their poor lipid solubility or improper molecular size, resulting in poor absorption and hence poor bioavailability. Nowadays with the advancement in the technology, novel drug delivery systems open the door towards the development of enhancing bioavailability of herbal drug delivery systems. For last one decade many novel carriers such as liposomes, microspheres, nanoparticles, transferosomes, ethosomes, lipid based systems etc. have been reported for successful modified delivery of various herbal drugs. Many herbal compounds including quercetin, genistein, naringin, sinomenine, piperine, glycyrrhizin and nitrile glycoside have demonstrated capability to enhance the bioavailability. The objective of this review is to summarize various available novel drug delivery technologies which have been developed for delivery of drugs (herbal), and to achieve better therapeutic response. An attempt has also been made to compile a profile on bioavailability enhancers of herbal origin with the mechanism of action (wherever reported) and studies on improvement in drug bioavailability, exhibited particularly by natural compounds.

  1. Bioavailability enhancers of herbal origin: An overview

    Science.gov (United States)

    Kesarwani, Kritika; Gupta, Rajiv

    2013-01-01

    Recently, the use of herbal medicines has been increased all over the world due to their therapeutic effects and fewer adverse effects as compared to the modern medicines. However, many herbal drugs and herbal extracts despite of their impressive in-vitro findings demonstrates less or negligible in-vivo activity due to their poor lipid solubility or improper molecular size, resulting in poor absorption and hence poor bioavailability. Nowadays with the advancement in the technology, novel drug delivery systems open the door towards the development of enhancing bioavailability of herbal drug delivery systems. For last one decade many novel carriers such as liposomes, microspheres, nanoparticles, transferosomes, ethosomes, lipid based systems etc. have been reported for successful modified delivery of various herbal drugs. Many herbal compounds including quercetin, genistein, naringin, sinomenine, piperine, glycyrrhizin and nitrile glycoside have demonstrated capability to enhance the bioavailability. The objective of this review is to summarize various available novel drug delivery technologies which have been developed for delivery of drugs (herbal), and to achieve better therapeutic response. An attempt has also been made to compile a profile on bioavailability enhancers of herbal origin with the mechanism of action (wherever reported) and studies on improvement in drug bioavailability, exhibited particularly by natural compounds. PMID:23620848

  2. Bioavailability enhancers of herbal origin: An overview

    Directory of Open Access Journals (Sweden)

    Kritika Kesarwani

    2013-04-01

    Full Text Available Recently, the use of herbal medicines has been increased all over the world due to their therapeutic effects and fewer adverse effects as compared to the modern medicines. However, many herbal drugs and herbal extracts despite of their impressive in-vitro findings demonstrates less or negligible in-vivo activity due to their poor lipid solubility or improper molecular size, resulting in poor absorption and hence poor bioavailability. Nowadays with the advancement in the technology, novel drug delivery systems open the door towards the development of enhancing bioavailability of herbal drug delivery systems. For last one decade many novel carriers such as liposomes, microspheres, nanoparticles, transferosomes, ethosomes, lipid based systems etc. have been reported for successful modified delivery of various herbal drugs. Many herbal compounds including quercetin, genistein, naringin, sinomenine, piperine, glycyrrhizin and nitrile glycoside have demonstrated capability to enhance the bioavailability. The objective of this review is to summarize various available novel drug delivery technologies which have been developed for delivery of drugs (herbal, and to achieve better therapeutic response. An attempt has also been made to compile a profile on bioavailability enhancers of herbal origin with the mechanism of action (wherever reported and studies on improvement in drug bioavailability, exhibited particularly by natural compounds.

  3. Pharmacokinetics and bioavailability of drotaverine in humans.

    Science.gov (United States)

    Bolaji, O O; Onyeji, C O; Ogundaini, A O; Olugbade, T A; Ogunbona, F A

    1996-01-01

    The pharmacokinetics and bioavailability of drotaverine was studied in 10 healthy volunteers after administration of single 80 mg oral and intravenous doses of the HCl salt of the drug, in a crossover fashion. Plasma and urine samples were analyzed for the unchanged drug by HPLC. The pharmacokinetic parameters, such as elimination half-life, plasma clearance, renal clearance and apparent volume of distribution, were not influenced by the route of drug administration. The drug was mainly eliminated by non-renal routes since renal clearance accounted for only 0.31 +/- 0.13% of the total plasma clearance. The absolute bioavailability was variable and ranged from 24.5-91% with a mean of 58.2 +/- 18.2% (mean +/- SD). It is suggested that the high variation in the bioavailability of drotaverine HCl after oral administration may result in significant interindividual differences in therapeutic response.

  4. Polymeric microcontainers improve oral bioavailability of furosemide

    DEFF Research Database (Denmark)

    Nielsen, Line Hagner; Melero, Ana; Keller, Stephan Sylvest

    2016-01-01

    with Eudragit and compared to a furosemide solution. The absorption rate constant of ASSF confined in microcontainers is found to be significantly different from the solution, and by light microscopy, it is observed that the microcontainers are engulfed by the intestinal mucus. An oral bioavailability study...... in rats is performed with ASSF confined in microcontainers coated with Eudragit and a control group with ASSF in Eudragit-coated capsules. A relative bioavailability of 220% for the ASSF in microcontainers compared to ASSF in capsules is found. These studies indicate that the microcontainers could serve...

  5. Bioavailability of Metal Ions and Evolutionary Adaptation

    Directory of Open Access Journals (Sweden)

    Rolando P. Hong Enriquez

    2012-10-01

    Full Text Available The evolution of life on earth has been a long process that began nearly 3,5 x 109 years ago. In their initial moments, evolution was mainly influenced by anaerobic environments; with the rise of O2 and the corresponding change in bioavailability of metal ions, new mechanisms of survival were created. Here we review the relationships between ancient atmospheric conditions, metal ion bioavailability and adaptation of metals homeostasis during early evolution. A general picture linking geochemistry, biochemistry and homeostasis is supported by the reviewed literature and is further illustrated in this report using simple database searches.

  6. Bioavailability of glucosinolates and their breakdown products

    DEFF Research Database (Denmark)

    Barba Orellana, Francisco Jose; Nikmaram, Nooshin; Roohinejad, Shahin

    2016-01-01

    Glucosinolates are a large group of plant secondary metabolites with nutritional effects, and are mainly found in cruciferous plants. After ingestion, glucosinolates could be partially absorbed in their intact form through the gastrointestinal mucosa. However, the largest fraction is metabolized ...... the bioavailability of glucosinolates and their breakdown products. This review paper summarizes the assimilation, absorption, and elimination of these molecules, as well as the impact of processing on their bioavailability.......Glucosinolates are a large group of plant secondary metabolites with nutritional effects, and are mainly found in cruciferous plants. After ingestion, glucosinolates could be partially absorbed in their intact form through the gastrointestinal mucosa. However, the largest fraction is metabolized...

  7. Animal versus human oral drug bioavailability: do they correlate?

    Science.gov (United States)

    Musther, Helen; Olivares-Morales, Andrés; Hatley, Oliver J D; Liu, Bo; Rostami Hodjegan, Amin

    2014-06-16

    Oral bioavailability is a key consideration in development of drug products, and the use of preclinical species in predicting bioavailability in human has long been debated. In order to clarify whether any correlation between human and animal bioavailability exist, an extensive analysis of the published literature data was conducted. Due to the complex nature of bioavailability calculations inclusion criteria were applied to ensure integrity of the data. A database of 184 compounds was assembled. Linear regression for the reported compounds indicated no strong or predictive correlations to human data for all species, individually and combined. The lack of correlation in this extended dataset highlights that animal bioavailability is not quantitatively predictive of bioavailability in human. Although qualitative (high/low bioavailability) indications might be possible, models taking into account species-specific factors that may affect bioavailability are recommended for developing quantitative prediction.

  8. Mouse Assay for Determination of Arsenic Bioavailability in Contaminated Soils

    Science.gov (United States)

    Background: Accurate assessment of human exposure estimates from arsenic-contaminated soils depends upon estimating arsenic (As) soil bioavailability. Development of bioavailability assays provides data needed for human health risk assessments and supports development and valida...

  9. Enhanced bioavailability of opiates after intratracheal administration

    Energy Technology Data Exchange (ETDEWEB)

    Findlay, J.W.A.; Jones, E.C.; McNulty, M.J.

    1986-03-01

    Several opiate analgesics have low oral bioavailabilities in the dog because of presystemic metabolism. Intratracheal administration may circumvent this first-pass effect. Three anesthetized beagles received 5-mg/kg doses of codeine phosphate intratracheally (i.t.), orally (p.o.) and intravenously (i.v.) in a crossover study. The following drugs were also studied in similar experiments: ethylmorphine hydrochloride (5 mg/kg), pholcodine bitartrate (10 mg/kg, hydrocodone bitartrate (4 mg/kg) and morphine sulfate (2.5 mg/kg). Plasma drug concentrations over the 24- to 48-hr periods after drug administrations were determined by radioimmunoassays. I.t. bioavailabilities (codeine (84%), ethylmorphine (100%), and morphine (87%)) of drugs with poor oral availabilities were all markedly higher than the corresponding oral values (14, 26, and 23%, respectively). I.t. bioavailabilities of pholcodine (93%) and hydrocodone (92%), which have good oral availabilities (74 and 79%, respectively), were also enhanced. In all cases, peak plasma concentrations occurred more rapidly after i.t. (0.08-0.17 hr) than after oral (0.5-2 hr) dosing and i.t. disposition often resembled i.v. kinetics. I.t. administration may be a valuable alternative dosing route, providing rapid onset of pharmacological activity for potent drugs with poor oral bioavailability.

  10. Bioavailability enhancement of glucosamine hydrochloride by chitosan.

    Science.gov (United States)

    Qian, Shuai; Zhang, Qizhi; Wang, Yanfeng; Lee, Benjamin; Betageri, Guru V; Chow, Moses S S; Huang, Min; Zuo, Zhong

    2013-10-15

    Glucosamine, as a dietary supplement for management of osteoarthritis, has a low and erratic oral bioavailability due to its transport-mediated absorption and presystemic loss in liver and GI tract. The present study described an effective approach to improve glucosamine intestinal absorption and hence its bioavailability using chitosan. Effects of chitosan on intestinal permeability and pharmacokinetics of glucosamine were evaluated in Caco-2 cell monolayer and rats, respectively. In addition, randomized crossover pharmacokinetic studies in beagle dogs were performed to evaluate the oral bioavailabilities of the developed glucosamine oral formulations containing chitosan (QD-Glu solution and QD-Glu tablet) in comparison to its commercial products. Caco-2 permeability studies demonstrated that chitosan could enhance the absorptive transport of glucosamine by 1.9-4.0-fold via the reversible opening of the cell tight junction. After oral administration of glucosamine solutions containing chitosan in rats, it was found that 0.5% (w/v) chitosan exhibited the highest enhancement in Cmax (2.8-fold) and AUC0-∞ (2.5-fold) of glucosamine. Further pharmacokinetic studies in beagle dogs demonstrated that QD-Glu solution and QD-Glu tablet showed much higher relative bioavailabilities of 313% and 186%, when comparing with Wellesse™ solution and Voltaflex™ tablet, respectively. In conclusion, chitosan could serve as a promising oral absorption enhancer for glucosamine.

  11. Bioavailability of cadmium from linseed and cocoa

    DEFF Research Database (Denmark)

    Hansen, Max; Sloth, Jens Jørgen; Rasmussen, Rie Romme

    In Denmark and EU the exposure of cadmium from food is at a level that is relatively close to the Tolerable Daily Intake (TDI). This report describes an investigation of the bioavailability of cadmium in selected food items known to contain high levels of cadmium. The purpose was to provide data ...... or crushed linseed nor the intake of cocoa and chocolate....

  12. Absorption, bioavailability and metabolism of flavonoids

    NARCIS (Netherlands)

    Hollman, P.C.H.

    2004-01-01

    To unravel mechanisms of action of dietary flavonoids in their potential role in disease prevention, it is crucial to know the factors that determine their release from foods, their extent of absorption, and their fate in the organism. Research on absorption, metabolism, and bioavailability of flavo

  13. Bioavailability and Bioequivalence in Drug Development.

    Science.gov (United States)

    Chow, Shein-Chung

    2014-01-01

    Bioavailability is referred to as the extent and rate to which the active drug ingredient or active moiety from the drug product is absorbed and becomes available at the site of drug action. The relative bioavailability in terms of the rate and extent of drug absorption is considered predictive of clinical outcomes. In 1984, the United States Food and Drug Administration (FDA) was authorized to approve generic drug products under the Drug Price Competition and Patent Term Restoration Act based on evidence of average bioequivalence in drug absorption through the conduct of bioavailability and bioequivalence studies. This article provides an overview (from an American point of view) of definition of bioavailability and bioequivalence, Fundamental Bioequivalence Assumption, regulatory requirements, and process for bioequivalence assessment of generic drug products. Basic considerations including criteria, study design, power analysis for sample size determination, and the conduct of bioequivalence trial, and statistical methods are provided. Practical issues such as one size-fits-all criterion, drug interchangeability and scaled average criteria for assessment of highly variable drug products are also discussed.

  14. Geochemical Modeling of Zinc Bioavailability for Rice

    NARCIS (Netherlands)

    Gao, X.; Schröder, T.J.; Hoffland, E.; Zou, C.; Zhang, F.; Zee, van der S.E.A.T.M.

    2010-01-01

    The transition from anaerobic to aerobic rice (Oryza sativa L.) cultivation has been reported to decrease Zn bioavailability. To determine and understand the differences in plant Zn uptake between anaerobic and aerobic rice cultivation systems, a field plot experiment was conducted with direct-seede

  15. A DGT technique for plutonium bioavailability measurements.

    Science.gov (United States)

    Cusnir, Ruslan; Steinmann, Philipp; Bochud, François; Froidevaux, Pascal

    2014-09-16

    The toxicity of heavy metals in natural waters is strongly dependent on the local chemical environment. Assessing the bioavailability of radionuclides predicts the toxic effects to aquatic biota. The technique of diffusive gradients in thin films (DGT) is largely exploited for bioavailability measurements of trace metals in waters. However, it has not been applied for plutonium speciation measurements yet. This study investigates the use of DGT technique for plutonium bioavailability measurements in chemically different environments. We used a diffusion cell to determine the diffusion coefficients (D) of plutonium in polyacrylamide (PAM) gel and found D in the range of 2.06-2.29 × 10(-6) cm(2) s(-1). It ranged between 1.10 and 2.03 × 10(-6) cm(2) s(-1) in the presence of fulvic acid and in natural waters with low DOM. In the presence of 20 ppm of humic acid of an organic-rich soil, plutonium diffusion was hindered by a factor of 5, with a diffusion coefficient of 0.50 × 10(-6) cm(2) s(-1). We also tested commercially available DGT devices with Chelex resin for plutonium bioavailability measurements in laboratory conditions and the diffusion coefficients agreed with those from the diffusion cell experiments. These findings show that the DGT methodology can be used to investigate the bioaccumulation of the labile plutonium fraction in aquatic biota.

  16. Bioavailability of voriconazole in hospitalised patients.

    Science.gov (United States)

    Veringa, Anette; Geling, Sanne; Span, Lambert F R; Vermeulen, Karin M; Zijlstra, Jan G; van der Werf, Tjip S; Kosterink, Jos G W; Alffenaar, Jan-Willem C

    2017-02-01

    An important element in antimicrobial stewardship programmes is early switch from intravenous (i.v.) to oral antimicrobial treatment, especially for highly bioavailable drugs. The antifungal agent voriconazole is available both in i.v. and oral formulations and bioavailability is estimated to be >90% in healthy volunteers, making this drug a suitable candidate for such a transition. Recently, two studies have shown that the bioavailability of voriconazole is substantially lower in patients. However, for both studies various factors that could influence the voriconazole serum concentration, such as inflammation, concomitant intake of food with oral voriconazole, and gastrointestinal complications, were not included in the evaluation. Therefore, in this study a retrospective chart review was performed in adult patients treated with both oral and i.v. voriconazole at the same dose and within a limited (≤5 days) time interval in order to evaluate the effect of switching the route of administration on voriconazole serum concentrations. A total of 13 patients were included. The mean voriconazole trough concentration was 2.28 mg/L [95% confidence interval (CI) 1.29-3.26 mg/L] for i.v. voriconazole administration and 2.04 mg/L (95% CI 0.78-3.30 mg/L) for oral administration. No significant difference was found in the mean oral and i.v. trough concentrations of voriconazole (P = 0.390). The mean bioavailability was 83.0% (95% CI 59.0-107.0%). These findings suggest that factors other than bioavailability may cause the observed difference in voriconazole trough concentrations between oral and i.v. administration in the earlier studies and stress the need for an antimicrobial stewardship team to guide voriconazole dosing.

  17. Heavy Metal Bioavailability and Bioaccessibility in Soil

    Science.gov (United States)

    Dean, John Richard

    This chapter considers the use of a variety of approaches to assess either the bioavailability or the bioaccessibility of metals in soil. The bioavailability of metals from soils is considered with respect to a series of single-extraction methods, including the use of ethylenediaminetetraacetic acid (EDTA), acetic acid, diethylenetriaminepentaacetic acid (DTPA), ammonium nitrate, calcium chloride and sodium nitrate. Then, a procedure for the recovery of metals using a three-stage sequential extraction protocol is described. Two alternate approaches for assessing the environmental health risk to humans by undertaking in vitro gastrointestinal extraction (also known as the physiologically based extraction test, PBET) are considered. Finally, two acid digestion protocols that allow the pseudo-total metal content of samples to be assessed are provided.

  18. Bioavailability enhancers of herbal origin: An overview

    OpenAIRE

    Kritika Kesarwani; Rajiv Gupta

    2013-01-01

    Recently, the use of herbal medicines has been increased all over the world due to their therapeutic effects and fewer adverse effects as compared to the modern medicines. However, many herbal drugs and herbal extracts despite of their impressive in-vitro findings demonstrates less or negligible in-vivo activity due to their poor lipid solubility or improper molecular size, resulting in poor absorption and hence poor bioavailability. Nowadays with the advancement in the technology, novel drug...

  19. Extraction, bioavailability, and bioefficacy of capsaicinoids

    OpenAIRE

    Muwen Lu; Chi-Tang Ho; Qingrong Huang

    2017-01-01

    Capsaicinoids are active constituents responsible for the pungent and spicy flavor in chili peppers. During the past few decades, various extraction methods of capsaicinoids from peppers have been developed with high yields. Through biological studies, pharmacological benefits have been reported such as pain relief, antiinflammation, anticancer, cardio-protection, as well as weight loss. In this paper, the extraction methods and bioavailability of capsaicinoids are reviewed and discussed. In ...

  20. Extraction, bioavailability, and bioefficacy of capsaicinoids

    Directory of Open Access Journals (Sweden)

    Muwen Lu

    2017-01-01

    Full Text Available Capsaicinoids are active constituents responsible for the pungent and spicy flavor in chili peppers. During the past few decades, various extraction methods of capsaicinoids from peppers have been developed with high yields. Through biological studies, pharmacological benefits have been reported such as pain relief, antiinflammation, anticancer, cardio-protection, as well as weight loss. In this paper, the extraction methods and bioavailability of capsaicinoids are reviewed and discussed. In addition, the pharmacological effects and their underlying mechanisms are also studied.

  1. Bioavailability and biodistribution of nanodelivered lutein.

    Science.gov (United States)

    Kamil, Alison; Smith, Donald E; Blumberg, Jeffrey B; Astete, Carlos; Sabliov, Cristina; Oliver Chen, C-Y

    2016-02-01

    The aim of the study was to evaluate the ability of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NP) to enhance lutein bioavailability. The bioavailability of free lutein and PLGA-NP lutein in rats was assessed by determining plasma pharmacokinetics and deposition in selected tissues. Lutein uptake and secretion was also assessed in Caco-2 cells. Compared to free lutein, PLGA-NP increased the maximal plasma concentration (Cmax) and area under the time-concentration curve in rats by 54.5- and 77.6-fold, respectively, while promoting tissue accumulation in the mesenteric fat and spleen. In comparison with micellized lutein, PLGA-NP lutein improved the Cmax in rat plasma by 15.6-fold and in selected tissues by ⩾ 3.8-fold. In contrast, PLGA-NP lutein had a lower uptake and secretion of lutein in Caco-2 cells by 10.0- and 50.5-fold, respectively, compared to micellized lutein. In conclusion, delivery of lutein with polymeric NP may be an approach to improve the bioavailability of lutein in vivo.

  2. Potassium Intake, Bioavailability, Hypertension, and Glucose Control

    Science.gov (United States)

    Stone, Michael S.; Martyn, Lisa; Weaver, Connie M.

    2016-01-01

    Potassium is an essential nutrient. It is the most abundant cation in intracellular fluid where it plays a key role in maintaining cell function. The gradient of potassium across the cell membrane determines cellular membrane potential, which is maintained in large part by the ubiquitous ion channel the sodium-potassium (Na+-K+) ATPase pump. Approximately 90% of potassium consumed (60–100 mEq) is lost in the urine, with the other 10% excreted in the stool, and a very small amount lost in sweat. Little is known about the bioavailability of potassium, especially from dietary sources. Less is understood on how bioavailability may affect health outcomes. Hypertension (HTN) is the leading cause of cardiovascular disease (CVD) and a major financial burden ($50.6 billion) to the US public health system, and has a significant impact on all-cause morbidity and mortality worldwide. The relationship between increased potassium supplementation and a decrease in HTN is relatively well understood, but the effect of increased potassium intake from dietary sources on blood pressure overall is less clear. In addition, treatment options for hypertensive individuals (e.g., thiazide diuretics) may further compound chronic disease risk via impairments in potassium utilization and glucose control. Understanding potassium bioavailability from various sources may help to reveal how specific compounds and tissues influence potassium movement, and further the understanding of its role in health. PMID:27455317

  3. Potassium Intake, Bioavailability, Hypertension, and Glucose Control

    Directory of Open Access Journals (Sweden)

    Michael S. Stone

    2016-07-01

    Full Text Available Potassium is an essential nutrient. It is the most abundant cation in intracellular fluid where it plays a key role in maintaining cell function. The gradient of potassium across the cell membrane determines cellular membrane potential, which is maintained in large part by the ubiquitous ion channel the sodium-potassium (Na+-K+ ATPase pump. Approximately 90% of potassium consumed (60–100 mEq is lost in the urine, with the other 10% excreted in the stool, and a very small amount lost in sweat. Little is known about the bioavailability of potassium, especially from dietary sources. Less is understood on how bioavailability may affect health outcomes. Hypertension (HTN is the leading cause of cardiovascular disease (CVD and a major financial burden ($50.6 billion to the US public health system, and has a significant impact on all-cause morbidity and mortality worldwide. The relationship between increased potassium supplementation and a decrease in HTN is relatively well understood, but the effect of increased potassium intake from dietary sources on blood pressure overall is less clear. In addition, treatment options for hypertensive individuals (e.g., thiazide diuretics may further compound chronic disease risk via impairments in potassium utilization and glucose control. Understanding potassium bioavailability from various sources may help to reveal how specific compounds and tissues influence potassium movement, and further the understanding of its role in health.

  4. Micronutrient bioavailability: Dietary Reference Intakes and a future perspective1234

    OpenAIRE

    2010-01-01

    This article provides a review of how the challenge of bioavailability was approached in establishing the Dietary Reference Intakes, with a special focus on folic acid, vitamin B-12, β-carotene, iron, selenium, and zinc, the targeted micronutrients for this workshop. In a future perspective, the necessity of having a clear working definition of bioavailability is emphasized. The bioavailability of micronutrients should be considered, with advantage, under subheadings determined by the broad f...

  5. Isoflavones: estrogenic activity, biological effect and bioavailability.

    Science.gov (United States)

    Vitale, Daniela Cristina; Piazza, Cateno; Melilli, Barbara; Drago, Filippo; Salomone, Salvatore

    2013-03-01

    Isoflavones are phytoestrogens with potent estrogenic activity; genistein, daidzein and glycitein are the most active isoflavones found in soy beans. Phytoestrogens have similarity in structure with the human female hormone 17-β-estradiol, which can bind to both alpha and beta estrogen receptors, and mimic the action of estrogens on target organs, thereby exerting many health benefits when used in some hormone-dependent diseases. Numerous clinical studies claim benefits of genistein and daidzein in chemoprevention of breast and prostate cancer, cardiovascular disease and osteoporosis as well as in relieving postmenopausal symptoms. The ability of isoflavones to prevent cancer and other chronic diseases largely depends on pharmacokinetic properties of these compounds, in particular absorption and distribution to the target tissue. The chemical form in which isoflavones occur is important because it influences their bioavailability and, therefore, their biological activity. Glucose-conjugated isoflavones are highly polar, water-soluble compounds. They are hardly absorbed by the intestinal epithelium and have weaker biological activities than the corresponding aglycone. Different microbial families of colon can transform glycosylated isoflavones into aglycones. Clinical studies show important differences between the aglycone and conjugated forms of genistein and daidzein. The evaluation of isoflavone metabolism and bioavailability is crucial to understanding their biological effects. Lipid-based formulations such as drug incorporation into oils, emulsions and self-microemulsifying formulations have been introduced to increase bioavailability. Complexation with cyclodextrin also represent a valid method to improve the physicochemical characteristics of these substances in order to be absorbed and distributed to target tissues. We review and discuss pharmacokinetic issues that critically influence the biological activity of isoflavones.

  6. Bioavailability of bioactive food compounds: a challenging journey to bioefficacy.

    Science.gov (United States)

    Rein, Maarit J; Renouf, Mathieu; Cruz-Hernandez, Cristina; Actis-Goretta, Lucas; Thakkar, Sagar K; da Silva Pinto, Marcia

    2013-03-01

    Bioavailability is a key step in ensuring bioefficacy of bioactive food compounds or oral drugs. Bioavailability is a complex process involving several different stages: liberation, absorption, distribution, metabolism and elimination phases (LADME). Bioactive food compounds, whether derived from various plant or animal sources, need to be bioavailable in order to exert any beneficial effects. Through a better understanding of the digestive fate of bioactive food compounds we can impact the promotion of health and improvement of performance. Many varying factors affect bioavailability, such as bioaccessibility, food matrix effect, transporters, molecular structures and metabolizing enzymes. Bioefficacy may be improved through enhanced bioavailability. Therefore, several technologies have been developed to improve the bioavailability of xenobiotics, including structural modifications, nanotechnology and colloidal systems. Due to the complex nature of food bioactive compounds and also to the different mechanisms of absorption of hydrophilic and lipophilic bioactive compounds, unravelling the bioavailability of food constituents is challenging. Among the food sources discussed during this review, coffee, tea, citrus fruit and fish oil were included as sources of food bioactive compounds (e.g. (poly)phenols and polyunsaturated fatty acids (PUFAs)) since they are examples of important ingredients for the food industry. Although there are many studies reporting on bioavailability and bioefficacy of these bioactive food components, understanding their interactions, metabolism and mechanism of action still requires extensive work. This review focuses on some of the major factors affecting the bioavailability of the aforementioned bioactive food compounds.

  7. Bioavailability of Micronutrients from Plant Foods: An Update.

    Science.gov (United States)

    Platel, Kalpana; Srinivasan, Krishnapura

    2016-07-26

    Deficiencies of iron, zinc, iodine and vitamin A are widespread in the developing countries, poor bioavailability of these micronutrients from plant-based foods being the major reason for their wide prevalence. Diets predominantly vegetarian are composed of components that enhance as well as inhibit mineral bioavailability, the latter being predominant. However, prudent cooking practices and use of ideal combinations of food components can significantly improve micronutrient bioavailability. Household processing such as heat treatment, sprouting, fermentation and malting have been evidenced to enhance the bioavailability of iron and β-carotene from plant foods. Food acidulants amchur and lime are also shown to enhance the bioavailability of not only iron and zinc, but also of β-carotene. Recently indentified newer enhancers of micronutrient bioaccessibility include sulphur compound-rich Allium spices-onion and garlic, which also possess antioxidant properties, β-carotene-rich vegetables-carrot and amaranth, and pungent spices-pepper (both red and black) as well as ginger. Information on the beneficial effect of these dietary compounds on micronutrient bioaccessibility is novel. These food components evidenced to improve the bioavailability of micronutrients are common ingredients of Indian culinary, and probably of other tropical countries. Fruits such as mango and papaya, when consumed in combination with milk, provide significantly higher amounts of bioavailable β-carotene. Awareness of the beneficial influence of these common dietary ingredients on the bioavailability of micronutrients would help in devising dietary strategies to improve the bioavailability of these vital nutrients.

  8. Bioavailability and bioavailable forms of collagen after oral administration to rats.

    Science.gov (United States)

    Wang, Lin; Wang, Qing; Qian, Jing; Liang, Qiufang; Wang, Zhenbin; Xu, Junmin; He, Song; Ma, Haile

    2015-04-15

    The bioavailability and bioavailable forms of collagen after oral administration to rats were investigated in this study. The relative and absolute bioavailability of collagen were 57.8% and 49.6%, respectively, which was indirectly evaluated by the bioavailability of Hyp in collagen using a pharmacokinetic method. The amino acid profile of plasma showed that more than 63.4% of the collagen was absorbed from the intestine in the form of peptide, and there was a good linear correlation between the absorbed amount of an amino acid and its content in collagen (R(2) = 0.9225). The collagen peptides in plasma were purified by Sephadex G10 and Eclipse XDB C18 chromatography and further indentified (Ala-Asn, Ala-Hyp-Gly, Asp-Glu, Glu-Asn, Glu-Asp, Glu-Met, Gly-Pro-Hyp, Leu-Hyp, Leu-Met, Phe-Gly-Asn, Pro-Gly-Leu, Pro-Leu, Ser-Gly-Met, Ser-Hyp, Ser-Pro-Gly, Tyr-Met) with UPLC-ESI-MS. These results may help to speculate about the molecular mechanism behind the physiological effects of collagen after oral administration.

  9. Bioavailability of cadmium from linseed and cocoa

    DEFF Research Database (Denmark)

    Hansen, Max; Rasmussen, Rie Romme; Sloth, Jens Jørgen

    2014-01-01

    for the food authorities in order to give correct advises to the population. The aim of this study was to investigate the bioavailability of cadmium from whole linseed, crushed linseed, cocoa and cadmium chloride in rats. An experiment where 40 rats were divided into 4 groups and a control group and dosed...... with whole linseed, crushed linseed, cocoa and CdCl2 for 3 weeks was performed. Linseed or cocoa made up 10% of the feed (by weight) and was added as a replacement for carbohydrate source. The rats were dosed for 3 weeks and the cadmium content in the rats' kidneys was measured by ICPMS as a biomarker...... be measured in the kidney compared to the calculated total intake was as follows: Control 2.0 %, Crushed linseed 0.9 %, whole linseed, 1.5 %, cocoa 0.7 % and CdCl2 4.6 %. Based on this study it could not be concluded that the bioavailability in rats form whole linseed is lower that for crushed linseed...

  10. Tyramine pharmacokinetics and reduced bioavailability with food.

    Science.gov (United States)

    VanDenBerg, Chad M; Blob, Lawrence F; Kemper, Eva M; Azzaro, Albert J

    2003-06-01

    Tyramine challenge studies have demonstrated that it requires approximately twice the amount of tyramine administered with a meal compared to administration after a fast to elicit the same effect, suggesting a reduction in bioavailability of tyramine when administered with food. The pharmacokinetics of tyramine when administered in a fasted versus a fed state were studied. A single 200-mg dose of tyramine was administered orally to healthy subjects both after an overnight fast and during a meal. Systemic exposure to tyramine was reduced by 53% (p tyramine was reduced by 72% (p Tyramine maximum serum concentration was observed between 20 minutes and 1 hour when the dose was administered after an overnight fast and appeared to be delayed and/or prolonged by administration during a meal. Tyramine oral clearance was 135 +/- 55.4 L/min, maximum observed serum concentration was 37.7 +/- 26.01 ng/mL, and tyramine elimination half-life was 0.533 (range: 0.330-0.668) hours after administration to fasted subjects. Tyramine bioavailability was significantly reduced when administered with a meal compared to after a fast. The results suggest that larger amounts of dietary tyramine will be required to induce a pressor response equivalent to that following encapsulated tyramine administered in the fasted state.

  11. Bioavailability of sustained-release theophylline formulations.

    Science.gov (United States)

    Bonora Regazzi, M; Rondanelli, R; Vidale, E; Cristiani, D

    1983-05-01

    Sustained-release formulations of theophylline as well as of other drugs are designed to effect a delayed but constant release of the active principle in the gastrointestinal tract, thus ensuring more prolonged blood level curves. This study was made to assess the bioavailability of two sustained-release microencapsulated formulations and one sustained-release Diffucaps formulation, in comparison with an equivalent dose of theophylline solution. As regards bioavailability, none of the three formulations differed significantly from the reference formulation. The blood levels at steady state were estimated on the basis of data obtained after a single-dose study. All three sustained release formulations showed good results after prolonged administration in terms of peaks and troughs. The time duration at which the theophylline plasma levels remain higher than 75% of the maximum steady-state levels, following 12-h dosing interval, was evaluated: for the sustained-release microencapsulated formulations this time duration reaches 100% of the dosing interval. A multiple-dose administration of the sustained-release formulations used in this study should guarantee almost complete time coverage, with blood levels sharply exceeding the minimum threshold level of the theophylline therapeutic range.

  12. Vitamin B12 sources and bioavailability.

    Science.gov (United States)

    Watanabe, Fumio

    2007-11-01

    The usual dietary sources of vitamin B(12) are animal foods, meat, milk, egg, fish, and shellfish. As the intrinsic factor-mediated intestinal absorption system is estimated to be saturated at about 1.5-2.0 microg per meal under physiologic conditions, vitamin B(12) bioavailability significantly decreases with increasing intake of vitamin B(12) per meal. The bioavailability of vitamin B(12) in healthy humans from fish meat, sheep meat, and chicken meat averaged 42%, 56%-89%, and 61%-66%, respectively. Vitamin B(12) in eggs seems to be poorly absorbed (vitamin B(12) is absorbed by healthy adults with normal gastro-intestinal function. Some plant foods, dried green and purple lavers (nori) contain substantial amounts of vitamin B(12), although other edible algae contained none or only traces of vitamin B(12). Most of the edible blue-green algae (cyanobacteria) used for human supplements predominantly contain pseudovitamin B(12), which is inactive in humans. The edible cyanobacteria are not suitable for use as vitamin B(12) sources, especially in vegans. Fortified breakfast cereals are a particularly valuable source of vitamin B(12) for vegans and elderly people. Production of some vitamin B(12)-enriched vegetables is also being devised.

  13. Estimating Lead (Pb) Bioavailability In A Mouse Model

    Science.gov (United States)

    Children are exposed to Pb through ingestion of Pb-contaminated soil. Soil Pb bioavailability is estimated using animal models or with chemically defined in vitro assays that measure bioaccessibility. However, bioavailability estimates in a large animal model (e.g., swine) can be...

  14. BIOACCESSIBILITY TESTS ACCURATELY ESTIMATE BIOAVAILABILITY OF LEAD TO QUAIL

    Science.gov (United States)

    Hazards of soil-borne Pb to wild birds may be more accurately quantified if the bioavailability of that Pb is known. To better understand the bioavailability of Pb to birds, we measured blood Pb concentrations in Japanese quail (Coturnix japonica) fed diets containing Pb-contami...

  15. Quantifying folate bioavailability: a critical appraisal of methods

    NARCIS (Netherlands)

    Boonstra, A.; Verhoef, P.; West, C.E.

    2004-01-01

    Purpose of review Dietary reference intakes for folate rely on a good estimate of folate bioavailability from the general diet. In this review, current methods for quantifying the bioavailability of dietary folate and specific folate vitamers in humans are reviewed. Emphasis is on isotopic labeling

  16. Bioaccessibility tests accurately estimate bioavailability of lead to quail

    Science.gov (United States)

    Hazards of soil-borne Pb to wild birds may be more accurately quantified if the bioavailability of that Pb is known. To better understand the bioavailability of Pb, we incorporated Pb-contaminated soils or Pb acetate into diets for Japanese quail (Coturnix japonica), fed the quail for 15 days, and ...

  17. Micronutrient bioavailability: Dietary Reference Intakes and a future perspective.

    Science.gov (United States)

    Hambidge, K Michael

    2010-05-01

    This article provides a review of how the challenge of bioavailability was approached in establishing the Dietary Reference Intakes, with a special focus on folic acid, vitamin B-12, beta-carotene, iron, selenium, and zinc, the targeted micronutrients for this workshop. In a future perspective, the necessity of having a clear working definition of bioavailability is emphasized. The bioavailability of micronutrients should be considered, with advantage, under subheadings determined by the broad factors that affect bioavailability. Special emphasis is given to giving greater and specific attention to factors involved in the maintenance of homeostasis. These factors, it is argued, are best considered separately from even a broad definition of bioavailability and have the potential to provide new insights into some micronutrient requirements.

  18. On definition and use of the term bioavailability.

    Science.gov (United States)

    Rescigno, A; Thakur, A K; Marzo, A

    1994-10-01

    In common usage, the rate of absorption of an active ingredient or its therapeutic moiety is generally not mentioned in the context of bioavailability. In this communication it is shown that exclusion of the rate of absorption may have serious consequence on the interpretation of bioavailability depending on the underlying model for the system under study. In the case of endogenous substances, the term "bioavailability" is ambiguous unless one specifies whether it refers to availability of the exogenous substance only or the sum total of the exogenous and endogenous substances.

  19. 21 CFR 320.30 - Inquiries regarding bioavailability and bioequivalence requirements and review of protocols by...

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Inquiries regarding bioavailability and... FOR HUMAN USE BIOAVAILABILITY AND BIOEQUIVALENCE REQUIREMENTS Procedures for Determining the Bioavailability or Bioequivalence of Drug Products § 320.30 Inquiries regarding bioavailability and...

  20. Marine lipids and the bioavailability of omega-3 fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Müllertz, Anette

    2015-01-01

    Marine lipids are enriched with omega-3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Omega-3 fatty acids are important membrane lipids and have many recognized health benefits, the bioavailability of these fatty acids can therefore be important for achieving...... of omega-3 fatty acids has been reported to be affected by several factors; among the important factors were the digestion and absorption processes of omega-3 containing lipids in the gastrointestinal tract. Both lipid structures and food structures can affect the bioavailability of omega-3 fatty acids....... Human studies have shown that the relative bioavailability of omega-3 fatty acids from fish oil (triglyceride formulation) was similar to that from fish, whereas lower relative bioavailability was observed from fatty acid ethyl ester (FAEE) formulation in comparison with other lipid formulations...

  1. Maltodextrin based proniosomes of nateglinide: bioavailability assessment.

    Science.gov (United States)

    Sahoo, Ranjan Ku; Biswas, Nikhil; Guha, Arijit; Kuotsu, Ketousetuo

    2014-08-01

    The present study delineates the fabrication of maltodextrin based proniosomes of nateglinide and their potential as controlled delivery system for diabetic therapy. New Zealand albino male rabbits have been used as animal model for in vivo study. To evaluate the bioavailability of nateglinide proniosome, a rapid, simple and sensitive HPLC method with photodiode array detection was developed and validated to determine nateglinide in rabbit plasma. Chromatographic separation was achieved by a reverse phase C18 column using a mixture of acetonitrile:methanol:10mM phosphate buffer (pH 3.5) in the ratio of 56:14:30 (%v/v) as the mobile phase at a flow rate of 1.0ml/min and quantified based on drug/IS peak area ratios. Gliclazide was used as the internal standard. The intra- and inter-day relative standard deviations of four tested concentrations were below 2%. The nateglinide proniosome formulation exhibited significantly higher plasma concentration than those of pure drug. The study revealed that the rate and extent of absorption of nateglinide from the proniosomal formulation was comparatively enhanced that of pure drug. Maltodextrin based proniosomes of nateglinide is not only simple and cost efficient delivery but also offers a useful and promising carrier for diabetic therapy through oral administration.

  2. Bioaccessibility tests accurately estimate bioavailability of lead to quail

    Science.gov (United States)

    Beyer, W. Nelson; Basta, Nicholas T; Chaney, Rufus L.; Henry, Paula F.; Mosby, David; Rattner, Barnett A.; Scheckel, Kirk G.; Sprague, Dan; Weber, John

    2016-01-01

    Hazards of soil-borne Pb to wild birds may be more accurately quantified if the bioavailability of that Pb is known. To better understand the bioavailability of Pb to birds, we measured blood Pb concentrations in Japanese quail (Coturnix japonica) fed diets containing Pb-contaminated soils. Relative bioavailabilities were expressed by comparison with blood Pb concentrations in quail fed a Pb acetate reference diet. Diets containing soil from five Pb-contaminated Superfund sites had relative bioavailabilities from 33%-63%, with a mean of about 50%. Treatment of two of the soils with phosphorus significantly reduced the bioavailability of Pb. Bioaccessibility of Pb in the test soils was then measured in six in vitro tests and regressed on bioavailability. They were: the “Relative Bioavailability Leaching Procedure” (RBALP) at pH 1.5, the same test conducted at pH 2.5, the “Ohio State University In vitro Gastrointestinal” method (OSU IVG), the “Urban Soil Bioaccessible Lead Test”, the modified “Physiologically Based Extraction Test” and the “Waterfowl Physiologically Based Extraction Test.” All regressions had positive slopes. Based on criteria of slope and coefficient of determination, the RBALP pH 2.5 and OSU IVG tests performed very well. Speciation by X-ray absorption spectroscopy demonstrated that, on average, most of the Pb in the sampled soils was sorbed to minerals (30%), bound to organic matter (24%), or present as Pb sulfate (18%). Additional Pb was associated with P (chloropyromorphite, hydroxypyromorphite and tertiary Pb phosphate), and with Pb carbonates, leadhillite (a lead sulfate carbonate hydroxide), and Pb sulfide. The formation of chloropyromorphite reduced the bioavailability of Pb and the amendment of Pb-contaminated soils with P may be a thermodynamically favored means to sequester Pb.

  3. The Extraction, Anticancer Effect, Bioavailability, and Nanotechnology of Baicalin

    Science.gov (United States)

    Moore, Ondrea A.; Gao, Ying; Chen, Allen Y.; Brittain, Ross; Chen, Yi Charlie

    2016-01-01

    The dried root of Baikal skullcap (Scutellaria baicalensis) has been historically and widely used in traditional Eastern medicine. Modern science proved that baicalin is the major bioactive responsible for the physiological activity of Baikal skullcap. Baicalin, a flavonoid found in several species in the genus Scutellaria, has been regarded as a potent anticancer agent. In this review, we present the main extraction methods, anticancer activity and bioavailability of baicalin. Besides, the utilization of nanotechnology to improve the bioavailability of baicalin is also mentioned.

  4. Bioavailability enhancement of atovaquone using hot melt extrusion technology.

    Science.gov (United States)

    Kate, Laxman; Gokarna, Vinod; Borhade, Vivek; Prabhu, Priyanka; Deshpande, Vinita; Pathak, Sulabha; Sharma, Shobhona; Patravale, Vandana

    2016-04-30

    Emerging parasite resistance and poor oral bioavailability of anti-malarials are the two cardinal issues which hinder the clinical success of malaria chemotherapy. Atovaquone-Proguanil is a WHO approved fixed dose combination used to tackle the problem of emerging resistance. However, Atovaquone is a highly lipophilic drug having poor aqueous solubility (less than 0.2 μg/ml) thus reducing its oral bioavailability. The aim of the present investigation was to explore hot melt extrusion (HME) as a solvent-free technique to enhance solubility and oral bioavailability of Atovaquone and to develop an oral dosage form for Atovaquone-Proguanil combination. Solid dispersion of Atovaquone was successfully developed using HME. The solid dispersion was characterized for DSC, FTIR, XRD, SEM, and flow properties. It was filled in size 2 hard gelatin capsules. The formulation showed better release as compared to Malarone® tablets, and 3.2-fold and 4.6-fold higher bioavailability as compared to Malarone® tablets and Atovaquone respectively. The enhanced bioavailability also resulted in 100% anti-malarial activity in murine infection model at 1/8(th) therapeutic dose. Thus the developed methodology shows promising potential to solve the problems associated with Atovaquone therapy, namely its high cost and poor oral bioavailability, resulting in increased therapeutic efficacy of Atovaquone.

  5. Bioaccumulation and bioavailability of polybrominated diphynel ethers (PBDEs) in soil

    Energy Technology Data Exchange (ETDEWEB)

    Liang Xianwei; Zhu Shuzhen; Chen Peng [College of Environmental Science and Engineering, Nankai University, Weijin Road 94, Tianjin 300071 (China); Key Laboratory of Pollution Processes and Environmental Criteria (Nankai University), Ministry of Education, Tianjin 300071 (China); Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071 (China); Zhu Lingyan, E-mail: zhuly@nankai.edu.c [College of Environmental Science and Engineering, Nankai University, Weijin Road 94, Tianjin 300071 (China); Key Laboratory of Pollution Processes and Environmental Criteria (Nankai University), Ministry of Education, Tianjin 300071 (China); Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071 (China)

    2010-07-15

    Earthworms were exposed to artificially contaminated soils of DE-71 and DE-79 to investigate the bioaccumulation and bioavailability of PBDEs in soil. All major congeners were bioavailable to earthworms. The uptake and elimination rate coefficients of PBDEs decreased with their logK{sub ow}s. The biota soil accumulation factors of PBDEs also declined with logK{sub ow}. These may be due to the large molecular size and the high affinity of PBDEs to soil particles. The concentrations extracted by Tenax for 6 h correlated very well with those found in earthworms, suggesting that the bioavailability of PBDEs in soil is related to the fraction of rapid desorption from soil. This also indicates that 6 h Tenax extraction is a good proxy for the bioavailability of PBDEs to earthworms in soil. The BSAFs of PBDEs in aged soil decreased 22-84% compared to freshly spiked soil, indicating that aging may diminish the bioavailability of PBDEs in soil significantly. - PBDEs are bioavailable to earthworms in soil and the uptake and elimination rate coefficients and BSAFs declined with their logK{sub ow}s.

  6. Trace metal speciation and bioavailability in anaerobic digestion: A review.

    Science.gov (United States)

    Thanh, Pham Minh; Ketheesan, Balachandran; Yan, Zhou; Stuckey, David

    2016-01-01

    Trace metals are essential for the growth of anaerobic microorganisms, however, in practice they are often added to anaerobic digesters in excessive amounts, which can lead to inhibition. The concept of bioavailability of metals in anaerobic digestion has been poorly understood in the past, and a lack of deep understanding of the relationship between trace metal speciation and bioavailability can result in ineffective metal dosing strategies for anaerobic digesters. Sequential extraction schemes are useful for fractionating trace metals into their different forms, and metal sulfides can serve as a store and source for trace metals during anaerobic digestion, while natural/synthetic chelating agents (soluble microbial products-SMPs, extracellular polysaccharides-EPS, and EDTA/NTA) are capable of controlling trace metal bioavailability. Nevertheless, more work is needed to: investigate the speciation and bioavailability of Ca, Mg, Mn, W, and Se; compare the bioavailability of different forms of trace metals e.g. carbonates, sulfides, phosphates to different anaerobic trophic groups; determine what factors influence metal sulfide dissolution; investigate whether chelating agents can increase trace metal bioavailability; develop and adapt specialized analytical techniques, and; determine how trace metal dynamics change in an anaerobic membrane bioreactor (AnMBR).

  7. Assessing arsenic bioavailability through the use of bioassays

    Science.gov (United States)

    Diesel, E.; Nadimpalli, M.; Hull, M.; Schreiber, M. E.; Vikesland, P.

    2009-12-01

    Various methods have been used to characterize the bioavailability of a contaminant, including chemical extractions from soils, toxicity tests, bioaccumulation measurements, estimation from soil properties, in vitro/in vivo tests, and microbial biossays. Unfortunately, these tests are all unique (i.e. they measure bioavailability through different mechanisms) and it is difficult to compare measurements collected using one method to those collected from another. Additionally, there are fundamental aspects of bioavailability research that require further study. In particular, changes in bioavailability over time are not well understood, as well as what the geochemical controls are on changes in bioavailability. In addition, there are no studies aimed at the integration of bioavailability measurements and potential geochemical controls. This research project seeks to find a standard set of assays and sensors that can be used to assess arsenic bioavailability at any field site, as well as to use these tools and techniques to better understand changes in, and controls on, arsenic bioavailability. The bioassays to be utilized in this research are a bioluminescent E. coli assay and a Corbicula fluminea (Asian clam) assay. Preliminary experiments to determine the suitability of the E. coli and C. fluminea assays have been completed. The E. coli assay can be utilized to analyze As(III) and As(V) with a linear standard curve between 5 and 200 ppb for As(III) and 100 ppb and 5 ppm for As(V); no bioluminescent response above background was elicited in the presence of Roxarsone, an organoarsenical. The C. fluminea assay is capable of bioaccumulating As(III), As(V), Roxarsone, and MSMA, with As(III) being the most readily accumulated, followed by As(V), Roxarsone and MSMA, respectively. Additional research will include assessing bioavailability of various arsenic species adsorbed to natural colloidal materials (i.e. clays, iron oxides, NOM) to the E. coli and C. fluminea assays

  8. Atorvastatin solid dispersion for bioavailability enhancement

    Directory of Open Access Journals (Sweden)

    Shamsuddin

    2016-01-01

    Full Text Available Atorvastatin calcium is a lipid-lowering agent. It has approximately 15% of bioavailability, remaining amount of drug showed adverse effect which is undesirable for patients. The objective of the study was to enhance the solubility and a dissolution profile of the atorvastatin (AT calcium. Solid dispersion (SD is a technique which enhances the solubility and a dissolution profile of poorly soluble drug. Various methods are being used for SDs such as microwave irradiation fusion, kneading, solvent evaporation, fusion, and dropping method. The authors have used here conventional fusion method using PEG 4000 as a hydrophilic carrier. The solubility of pure drug, physical mixture using PEG 4000 (1:3, and SD in phosphate buffer solutions (pH 6.8 was found to be 55.33 ± 0.66, 81.89 ± 2.35, and 93.66 ± 1.35, respectively. Fourier transform infrared and differential scanning calorimetry study showed the significant peak shift of drug in SD. It indicated that the nature of drug had been changed from crystalline form to amorphous form due to conversion into SD formulation. The dissolution rate was significantly increased when the drug polyethylene glycol 4000 ratio was 1:3. The mean cumulative percentage drugs release from pure drug, physical mixture, marketed tablet, and SD at 1 h was 28.92 ± 1.66%, 55.26 ± 0.95%, 72.16 ± 1.33%, and 91.66 ± 1.65%, respectively. It was concluded that the solubility and dissolution profile of SD of AT calcium showed the enhancement of solubility and dissolution when compared with marketed preparations.

  9. Speciation and bioavailability of lead in complementary medicines

    Energy Technology Data Exchange (ETDEWEB)

    Bolan, S., E-mail: Shiv.Bolan@UON.edu.au [School of Natural and Built Environments, University of South Australia, SA 5095 (Australia); Global Centre for Environmental Remediation (GCER), University of Newcastle, NSW 2308 (Australia); Naidu, R. [Global Centre for Environmental Remediation (GCER), University of Newcastle, NSW 2308 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), University of South Australia, SA 5095 (Australia); Kunhikrishnan, A. [Chemical Safety Division, Department of Agro–Food Safety, National Academy of Agricultural Science, Wanju-gun, Jeollabuk-do, 565-851 (Korea, Republic of); Seshadri, B. [Global Centre for Environmental Remediation (GCER), University of Newcastle, NSW 2308 (Australia); Ok, Y.S. [Korea Biochar Research Center & Department of Biological Environment, Kangwon National University, Chuncheon 200-701 (Korea, Republic of); Palanisami, T.; Dong, M. [Global Centre for Environmental Remediation (GCER), University of Newcastle, NSW 2308 (Australia); Clark, I. [School of Natural and Built Environments, University of South Australia, SA 5095 (Australia)

    2016-01-01

    Complementary medicines have associated risks which include toxic heavy metal(loid) and pesticide contamination. The objective of this study was to examine the speciation and bioavailability of lead (Pb) in selected complementary medicines. Six herbal and six ayurvedic medicines were analysed for: (i) total heavy metal(loid) contents including arsenic (As), cadmium (Cd), Pb and mercury (Hg); (ii) speciation of Pb using sequential fractionation and extended x-ray absorption fine structure (EXAFS) techniques; and (iii) bioavailability of Pb using a physiologically-based in vitro extraction test (PBET). The daily intake of Pb through the uptake of these medicines was compared with the safety guidelines for Pb. The results indicated that generally ayurvedic medicines contained higher levels of heavy metal(loid)s than herbal medicines with the amount of Pb much higher than the other metal(loid)s. Sequential fractionation indicated that while organic-bound Pb species dominated the herbal medicines, inorganic-bound Pb species dominated the ayurvedic medicines. EXAFS data indicated the presence of various Pb species in ayurvedic medicines. This implies that Pb is derived from plant uptake and inorganic mineral input in herbal and ayurvedic medicines, respectively. Bioavailability of Pb was higher in ayurvedic than herbal medicines, indicating that Pb added as a mineral therapeutic input is more bioavailable than that derived from plant uptake. There was a positive relationship between soluble Pb fraction and bioavailability indicating that solubility is an important factor controlling bioavailability. The daily intake values for Pb as estimated by total and bioavailable metal(loid) contents are likely to exceed the safe threshold level in certain ayurvedic medicines. This research demonstrated that Pb toxicity is likely to result from the regular intake of these medicines which requires further investigation. - Highlights: • Pb species in complementary medicines was

  10. Bioavailability enhancers of herbal origin:An overview

    Institute of Scientific and Technical Information of China (English)

    Kritika Kesarwani; Rajiv Gupta

    2013-01-01

    Recently, the use of herbal medicines has been increased all over the world due to their therapeutic effects and fewer adverse effects as compared to the modern medicines. However, many herbal drugs and herbal extracts despite of their impressive in-vitro findings demonstrates less or negligible in-vivo activity due to their poor lipid solubility or improper molecular size, resulting in poor absorption and hence poor bioavailability. Nowadays with the advancement in the technology, novel drug delivery systems open the door towards the development of enhancing bioavailability of herbal drug delivery systems. For last one decade many novel carriers such as liposomes, microspheres, nanoparticles, transferosomes, ethosomes, lipid based systems etc. have been reported for successful modified delivery of various herbal drugs. Many herbal compounds including quercetin, genistein, naringin, sinomenine, piperine, glycyrrhizin and nitrile glycoside have demonstrated capability to enhance the bioavailability. The objective of this review is to summarize various available novel drug delivery technologies which have been developed for delivery of drugs (herbal), and to achieve better therapeutic response. An attempt has also been made to compile a profile on bioavailability enhancers of herbal origin with the mechanism of action (wherever reported) and studies on improvement in drug bioavailability, exhibited particularly by natural compounds.

  11. Bioavailability enhancement of verapamil HCl via intranasal chitosan microspheres.

    Science.gov (United States)

    Abdel Mouez, Mamdouh; Zaki, Noha M; Mansour, Samar; Geneidi, Ahmed S

    2014-01-23

    Chitosan microspheres are potential drug carriers for maximizing nasal residence time, circumventing rapid mucociliary clearance and enhancing nasal absorption. The aim of the present study was to develop and characterize chitosan mucoadhesive microspheres of verapamil hydrochloride (VRP) for intranasal delivery as an alternative to oral VRP which suffers low bioavailability (20%) due to extensive first pass effect. The microspheres were produced using a spray-drying and precipitation techniques and characterized for morphology (scanning electron microscopy), particle size (laser diffraction method), drug entrapment efficiency, thermal behavior (differential scanning calorimetry) and crystallinity (X-ray diffractometric studies) as well as in vitro drug release. Bioavailability of nasal VRP microspheres was studied in rabbits and the results were compared to those obtained after nasal, oral and intravenous administration of VRP solution. Results demonstrated that the microspheres were spherical with size 21-53 μm suitable for nasal deposition. The spray-drying technique was superior over precipitation technique in providing higher VRP entrapment efficiency and smaller burst release followed by a more sustained one over 6h. The bioavailability study demonstrated that the nasal microspheres exhibited a significantly higher bioavailability (58.6%) than nasal solution of VRP (47.8%) and oral VRP solution (13%). In conclusion, the chitosan-based nasal VRP microspheres are promising for enhancing VRP bioavailability by increasing the nasal residence time and avoiding the first-pass metabolism of the drug substance.

  12. Biogeochemical controls of uranium bioavailability from the dissolved phase

    Science.gov (United States)

    Croteau, Marie-Noele; Fuller, Christopher C.; Cain, Daniel J.; Campbell, Kate M.; Aiken, George R.

    2016-01-01

    To gain insights into the risks associated with uranium (U) mining and processing, we investigated the biogeochemical controls of U bioavailability in the model freshwater speciesLymnaea stagnalis (Gastropoda). Bioavailability of dissolved U(VI) was characterized in controlled laboratory experiments over a range of water hardness, pH, and in the presence of complexing ligands in the form of dissolved natural organic matter (DOM). Results show that dissolved U is bioavailable under all the geochemical conditions tested. Uranium uptake rates follow first order kinetics over a range encompassing most environmental concentrations. Uranium uptake rates in L. stagnalis ultimately demonstrate saturation uptake kinetics when exposure concentrations exceed 100 nM, suggesting uptake via a finite number of carriers or ion channels. The lack of a relationship between U uptake rate constants and Ca uptake rates suggest that U does not exclusively use Ca membrane transporters. In general, U bioavailability decreases with increasing pH, increasing Ca and Mg concentrations, and when DOM is present. Competing ions did not affect U uptake rates. Speciation modeling that includes formation constants for U ternary complexes reveals that the aqueous concentration of dicarbonato U species (UO2(CO3)2–2) best predicts U bioavailability to L. stagnalis, challenging the free-ion activity model postulate

  13. In vivo bioavailability studies of sumatriptan succinate buccal tablets

    Directory of Open Access Journals (Sweden)

    B Jayakar

    2011-07-01

    Full Text Available    Back ground and the purpose of study: Sumatriptan succinate is a Serotonin 5- HT1 receptor agonist, used in treatment of migraine. It is absorbed rapidly but incompletely when given orally and undergoes first - pass metabolism, resulting in a low absolute bioavailability of about 15%. The aim of this work was to design mucoadhesive bilayered buccal tablets of sumatriptan succinate to improve its bioavailability. Methods:Mucoadhesive polymers carbopol 934 (Carbopol, HPMC K4M, HPMC K15M along with ethyl cellulose as an impermeable backing layer were used for the preparation of mucoadhesive bilayered tablets . In vivo bioavailability studies was also conducted in rabbits for optimized formulation using oral solution of sumatriptan succinate as standard. Results:Bilayered buccal tablets (BBT containing the mixture of Carbopol and HPMC K4M in the ratio 1:1 (T1 had the maximum percentage of in vitro drug release within 6 hrs. The optimized formulation (T1 followed non-Fickian release mechanism. The percentage relative bioavailability of sumatriptan succinate from selected bilayered buccal tablets (T1 was found to be 140.78%. Conclusions: Bilayered buccal tablets of sumatriptan succinate was successfully prepared with improved bioavailability.

  14. Bioavailability enhancers of herbal origin:An overview

    Institute of Scientific and Technical Information of China (English)

    Kritika; Kesarwani; Rajiv; Gupta

    2013-01-01

    Recently,the use of herbal medicines has been increased all over the world due to their therapeutic effects and fewer adverse effects as compared to the modern medicines.However,many herbal drugs and herbal extracts despite of their impressive in-vitro findings demonstrates less or negligible in-vivo activity due to their poor lipid solubility or improper molecular size,resulting in poor absorption and hence poor bioavailability.Nowadays with the advancement in the technology,novel drug delivery systems open the door towards the development of enhancing bioavailability of herbal drug delivery systems.For last one decade many novel carriers such as liposomes,microspheres,nanoparticles,transferosomes,ethosomes,lipid based systems etc.have been reported for successful modified delivery of various herbal drugs.Many herbal compounds including quercetin,genistein,naringin,sinomenine,pipeline,glycvrrhizin and nitrile glycoside have demonstrated capability to enhance the bioavailability.The objective of this review is to summarize various available novel drug delivery technologies which have been developed for delivery of drugs(herbal),and to achieve better therapeutic response.An attempt has also been made to compile a profile on bioavailability enhancers of herbal origin with the mechanism of action(wherever reported)and studies on improvement in drug bioavailability,exhibited particularly by natural compounds.

  15. Pharmacokinetic behaviors and oral bioavailability of oridonin in rat plasma

    Institute of Scientific and Technical Information of China (English)

    Wen XU; Jin SUN; Ting-ting ZHANG; Bo MA; Sheng-miao GUI; Da-wei CHEN; Zhong-gui HE

    2006-01-01

    Aim: To study the intravenous and oral pharmacokinetic behavior of oridonin and its extent of absolute oral bioavailability in rats. Methods: Oridonin was administered to rats via iv (5,10 and 15 mg/kg), po (20,40 and 80 mg/kg) or ip administration (10 mg/kg). The concentrations of oridonin in rat plasma were determined by a high performance liquid chromatography with electrospray ionization mass spec-trometric detection (HPLC/ESI-MS) method and the pharmacokinetic parameters were determined by non-compartmental analysis. Results: The plasma concentration of oridonin after intravenous administration decreased poly exponentially, and the pharmacokinetic parameters of oridonin were dose-independent within the examined range. Oridonin was absorbed rapidly after oral gavage with a bioavailability of oridonin following oral administration was 4.32%, 4.58% and 10.8%. The extent of absolute bioavailability of oridonin following intraperitoneal administration was 12.6%. Conclusion: First order rate pharmacokinetics were observed for oridonin within the range of iv doses, while the extent of absolute oral bioavailability was rather low and dose-dependent. The low and dose-dependent extent of oral bioavailability may be due to the saturation of first-pass effects.

  16. Permeability enhancers dramatically increase zanamivir absolute bioavailability in rats: implications for an orally bioavailable influenza treatment.

    Directory of Open Access Journals (Sweden)

    Eric H Holmes

    Full Text Available We have demonstrated that simple formulations composed of the parent drug in combination with generally regarded as safe (GRAS permeability enhancers are capable of dramatically increasing the absolute bioavailability of zanamivir. This has the advantage of not requiring modification of the drug structure to promote absorption, thus reducing the regulatory challenges involved in conversion of an inhaled to oral route of administration of an approved drug. Absolute bioavailability increases of up to 24-fold were observed when Capmul MCM L8 (composed of mono- and diglycerides of caprylic/capric acids in glycerol was mixed with 1.5 mg of zanamivir and administered intraduodenally to rats. Rapid uptake (t(max of 5 min and a C(max of over 7200 ng/mL was achieved. Variation of the drug load or amount of enhancer demonstrated a generally linear variation in absorption, indicating an ability to optimize a formulation for a desired outcome such as a targeted C(max for enzyme saturation. No absorption enhancement was observed when the enhancer was given 2 hr prior to drug administration, indicating, in combination with the observed tmax, that absorption enhancement is temporary. This property is significant and aligns well with therapeutic applications to limit undesirable drug-drug interactions, potentially due to the presence of other poorly absorbed polar drugs. These results suggest that optimal human oral dosage forms of zanamivir should be enteric-coated gelcaps or softgels for intraduodenal release. There continues to be a strong need and market for multiple neuraminidase inhibitors for influenza treatment. Creation of orally available formulations of inhibitor drugs that are currently administered intravenously or by inhalation would provide a significant improvement in treatment of influenza. The very simple GRAS formulation components and anticipated dosage forms would require low manufacturing costs and yield enhanced convenience. These results

  17. Improving oral bioavailability of acyclovir using nanoparticulates of thiolated xyloglucan.

    Science.gov (United States)

    Madgulkar, Ashwini; Bhalekar, Mangesh R; Dikpati, Amrita A

    2016-08-01

    Acyclovir a BCS class III drug exhibits poor bioavailability due to limited permeability. The intention of this research work was to formulate and characterize thiolated xyloglucan polysaccharide nanoparticles (TH-NPs) of acyclovir with the purpose of increasing its oral bioavailability. Acyclovir-loaded TH-NPs were prepared using a cross-linking agent. Interactions of formulation excipients were reconnoitered using Fourier transform infrared spectroscopy (FT-IR). The formulated nanoparticles were lyophilised by the addition of a cryoprotectant and characterized for its particle size, morphology and stability and optimized using Box Behnken Design.The optimized TH-NP formulation exhibited particle size of 474.4±2.01 and an entrapment efficiency of 81.57%. A marked enhancement in the mucoadhesion was also observed. In-vivo study in a rat model proved that relative bioavailability of acyclovir TH-NPs is ∼2.575 fold greater than that of the marketed acyclovir drug suspension.

  18. Size-fractionated production and bioavailability of dissolved organic matter

    DEFF Research Database (Denmark)

    Knudsen-Leerbeck, Helle; Bronk, Deborah A.; Markager, Stiig

    Production and bioavailability of dissolved organic matter was quantified on a time scale of two days from size fractions ranging from bacteria to zooplankton in the York River, Virginia. The goal was to find the main contributor to DOM. Batch incubation experiments were labeled with N15-ammonium...... was mainly in the phytoplankton size fraction, which on average contributed 62 % of total particulate nitrogen and 61 % of total particulate carbon. Up to 5 ± 0.4 μmol dissolved organic nitrogen L-1 and 33 ± 6.2 μmol dissolved organic carbon L-1 was produced during the incubation. Bioavailability...... of phytoplankton produced dissolved organic carbon was 12 ± 1 % and higher than in the presence of bacteria, microzooplankton, or copepods (7 ± 3 %). The pattern for bioavailability of dissolved organic nitrogen was less clear and ranged from 4 – 7 %. This study revealed that phytoplankton was the main contributor...

  19. Influence of milk products on fluoride bioavailability in man.

    Science.gov (United States)

    Ekstrand, J; Ehrnebo, M

    1979-09-01

    The effect of milk products on the gastrointestinal absorption of fluoride from sodium fluoride tablets was studied in five healthy subjects. Two different diets were tested: (1) 250 ml standardized milk (3% fat) and (2) 500 ml of milk, 3 pieces of white bread with cheese and 150 ml of yoghurt. The 100% bioavailability of sodium fluoride tablets during fasting was greatly decreased by coadministration of milk products: with Diet 1 the absolute bioavailability calculated from combined plasma and urine data was in the range 50--79% and with Diet 2 it ranged from 50--71%. It is suggested that the decreased bioavailability produced by dairy products should be taken into account when establishing flouride dosage regimens for prophylaxis of caries.

  20. Site dependent bioavailability and metabolism of levosimendan in dogs.

    Science.gov (United States)

    Antila, S; Huuskonen, H; Nevalainen, T; Kanerva, H; Vanninen, P; Lehtonen, L

    1999-10-01

    Site specific bioavailability and metabolism of levosimendan was studied in ten dogs by placing intestinal access port catheters in different parts of the gastrointestinal tract. 14C-labelled levosimendan (0.1 mg/kg) was administered intravenously, by gastric tube and directly through catheters that were placed in the duodenum, jejunum and ileum. Plasma samples were collected and radioactivity in the different organs and tissues was measured. The results of the present study showed that bioavailability of levosimendan was high varying from 71 to 86% after extravascular administration. Metabolite OR-1855 concentrations in the plasma were about 3-4 times higher after administration to the ileum compared to the other administration routes. It can be concluded that the bioavailability of levosimendan is not affected by site specific administration. The bacteria or enzymes responsible for the metabolism of levosimendan are located in the lower parts of the gastrointestinal tract.

  1. Bioavailability of long-chain omega-3 fatty acids.

    Science.gov (United States)

    Schuchardt, Jan Philipp; Hahn, Andreas

    2013-07-01

    Supplements have reached a prominent role in improving the supply of long-chain omega-3 fatty acids, such as Eicosapentaenoic acid (EPA 20:5n-3) and Docosahexaenoic acid (DHA 22:6n-3). Similar to other nutrients, the availability of omega-3 fatty acids is highly variable and determined by numerous factors. However, the question of omega-3 fatty acids bioavailability has long been disregarded, which may have contributed to the neutral or negative results concerning their effects in several studies. This review provides an overview of the influence of chemical binding form (free fatty acids bound in ethylesters, triacylglycerides or phospholipids), matrix effects (capsule ingestion with concomitant intake of food, fat content in food) or galenic form (i.e. microencapsulation, emulsification) on the bioavailability of omega-3 fatty acids. There is a need to systematically investigate the bioavailability of omega-3 fatty acids formulations, which might be a key to designing more effective studies in the future.

  2. Considering bioavailability in the remediation of heavy metal contaminated sites

    Directory of Open Access Journals (Sweden)

    Leita L.

    2013-04-01

    Full Text Available Many years of research have demonstrated that instead of the total concentration of metals in soil, bioavailability is the key to understand the environmental risk derived by metals, since adverse effects are related only to the biologically available forms of these elements. The knowledge of bioavailability can decrease the uncertainties in evaluating exposure in human and ecological risk assessment. At the same time, the efficiency of remediation treatments could be greatly influenced by availability of the contaminants. Consideration of the bioavailability processes at contaminated sites could be useful in site-specific risk assessment: the fraction of mobile metals, instead of total content should be provided as estimates of metal exposure. Moreover, knowledge of the chemical forms of heavy metals in soils is a critical component in the evaluation of applicability of different remediation technologies such as phytoremdiation or soil washing.

  3. Bioavailability of butachlor and myclobutanil residues in soil to earthworms.

    Science.gov (United States)

    Yu, Y L; Wu, X M; Li, S N; Fang, H; Tan, Y J; Yu, J Q

    2005-05-01

    To establish chemical extraction procedures for predicting bioavailability of butachlor and myclobutanil in soil, several solvent systems, including methanol, methanol-water (9:1), methanol-water (1:1), acetone-water (5:3), petroleum ether and water, were assessed for their feasibility in determining extractability of the target compounds from soil samples. Experimental data showed that the extractability of butachlor and myclobutanil by the solvents was well linearly correlated with their bioavailability to Eisenia foetida and Allolobophora caliginosa, indicating that these extraction procedures may be efficient for predicting bioavailability of the two pesticides. The concentrations of the pesticides accumulated in E. foetida and A. caliginosa varied with species, suggesting that the availability of the soil-sequestered pesticide is a species-dependent process.

  4. ENHANCED BIOAVAILABILITY OF DRUGS VIA INTRANASAL DRUG DELIVEY SYSTEM

    Directory of Open Access Journals (Sweden)

    kumar Brajesh

    2012-07-01

    Full Text Available The aim of present investigation is to explain the enhancement of bioavailability of drug through intranasal drug delivery system. Intranasal Therapy has been an accepted form of treatment in the Ayurvedic system of Indian Medicine. Recently, it has been shown that many drugs have better bioavailability by nasal route than the oral route. This has been attributed to rich vasculature and a highly permeable structure of the nasal mucosa coupled with avoidance of hepatic first-pass elimination, gut wall metabolism and/or destruction in the gastrointestinal tract. Intranasal microemulsion, gels, nanoparticles, liposome and microspheres have gained increased interest in recent years as a delivery system for protein and peptides through the nasal route. Thus this review focuses on nasal drug delivery, nasal drug absorption mechanisms, various mechanisms for increasing the bioavailability of drug, and their applications in drug delivery.

  5. Bioavailability of hydrochlorothiazide from isomalt-based moulded tablets.

    Science.gov (United States)

    Ndindayino, F; Vervaet, C; Van den Mooter, G; Remon, J P

    2002-10-10

    The bioavailability of hydrochlorothiazide (HCT) from moulded isomalt-based tablets was evaluated after oral administration of 50 mg HCT to healthy volunteers as an oral moulded tablet and as a lozenge, in comparison with a conventional tablet formulation (Dichlotride 50 mg). Moulded tablets had a high relative bioavailability (F(rel)) as the pharmacokinetic parameters (C(max), t(max), t(1/2), AUC(0-->24 h)) determined from HCT plasma concentration versus time profiles were not significantly different (P>0.05; two-way ANOVA) in comparison with the conventional tablet. The relative bioavailability of the moulded tablet administered as a lozenge and as an oral tablet was 106.2+/-30.9% and 89.4+/-25.9%, respectively, in relation to the conventional tablet formulation. Direct moulding of isomalt tablets proved to be a suitable technique to administer a poorly soluble drug either as a conventional tablet or as a lozenge.

  6. A Review of Mercury Bioavailability in Humans and Fish

    Science.gov (United States)

    Bradley, Mark A.; Barst, Benjamin D.; Basu, Niladri

    2017-01-01

    To estimate human exposure to methylmercury (MeHg), risk assessors often assume 95%–100% bioavailability in their models. However, recent research suggests that assuming all, or most, of the ingested mercury (Hg) is absorbed into systemic circulation may be erroneous. The objective of this paper is to review and discuss the available state of knowledge concerning the assimilation or bioavailability of Hg in fish and humans. In fish, this meant reviewing studies on assimilation efficiency, that is the difference between ingested and excreted Hg over a given period of time. In humans, this meant reviewing studies that mostly investigated bioaccessibility (digestive processes) rather than bioavailability (cumulative digestive + absorptive processes), although studies incorporating absorption for a fuller picture of bioavailability were also included where possible. The outcome of this review shows that in a variety of organisms and experimental models that Hg bioavailability and assimilation is less than 100%. Specifically, 25 studies on fish were reviewed, and assimilation efficiencies ranged from 10% to 100% for MeHg and from 2% to 51% for Hg(II). For humans, 20 studies were reviewed with bioaccessibility estimates ranging from 2% to 100% for MeHg and 0.2% to 94% for Hg(II). The overall absorption estimates ranged from 12% to 79% for MeHg and 49% to 69% for Hg(II), and were consistently less than 100%. For both fish and humans, a number of cases are discussed in which factors (e.g., Hg source, cooking methods, nutrients) are shown to affect Hg bioavailability. The summaries presented here challenge a widely-held assumption in the Hg risk assessment field, and the paper discusses possible ways forward for the field. PMID:28208586

  7. A Review of Mercury Bioavailability in Humans and Fish.

    Science.gov (United States)

    Bradley, Mark A; Barst, Benjamin D; Basu, Niladri

    2017-02-10

    To estimate human exposure to methylmercury (MeHg), risk assessors often assume 95%-100% bioavailability in their models. However, recent research suggests that assuming all, or most, of the ingested mercury (Hg) is absorbed into systemic circulation may be erroneous. The objective of this paper is to review and discuss the available state of knowledge concerning the assimilation or bioavailability of Hg in fish and humans. In fish, this meant reviewing studies on assimilation efficiency, that is the difference between ingested and excreted Hg over a given period of time. In humans, this meant reviewing studies that mostly investigated bioaccessibility (digestive processes) rather than bioavailability (cumulative digestive + absorptive processes), although studies incorporating absorption for a fuller picture of bioavailability were also included where possible. The outcome of this review shows that in a variety of organisms and experimental models that Hg bioavailability and assimilation is less than 100%. Specifically, 25 studies on fish were reviewed, and assimilation efficiencies ranged from 10% to 100% for MeHg and from 2% to 51% for Hg(II). For humans, 20 studies were reviewed with bioaccessibility estimates ranging from 2% to 100% for MeHg and 0.2% to 94% for Hg(II). The overall absorption estimates ranged from 12% to 79% for MeHg and 49% to 69% for Hg(II), and were consistently less than 100%. For both fish and humans, a number of cases are discussed in which factors (e.g., Hg source, cooking methods, nutrients) are shown to affect Hg bioavailability. The summaries presented here challenge a widely-held assumption in the Hg risk assessment field, and the paper discusses possible ways forward for the field.

  8. Bioavailability of sediment-bound contaminants to marine organisms

    Energy Technology Data Exchange (ETDEWEB)

    Brown, B. [Battelle/Marine Sciences Lab., Sequim, WA (United States)]|[Colby Coll., Waterville, ME (United States); Neff, J. [Battelle/Marine Sciences Lab., Sequim, WA (United States)]|[Battelle Ocean Sciences, Duxbury, MA (United States)

    1993-09-01

    The bioavailability of sediment-bound contaminants to marine organisms indicates that there exists a potential for transfer of these contaminants through marine food webs to commercial fisheries products consumed by humans. However, there has been relatively little effort to combine and synthesize data on chemical/biological interactions between benthic animals and seagrasses and the sediments in which they reside on the one hand, and on the chemistry of bioaccumulation on the other. This report provides a conceptual basis for an approach to bioavailability and biomagnification of sediment-bound contaminants that reviews biological and chemical approaches.

  9. Bioavailability of autochthonous dissolved organic nitrogen in marine plankton communities

    DEFF Research Database (Denmark)

    Knudsen, Helle; Markager, Svend Stiig; Søndergaard, Morten

    The purpose of this study was to investigate the bioavailability of dissolved organic nitrogen (DON) produced during a phytoplankton bloom. The experiments were conducted with natural plankton communities as batch growth experiments over approximately 30 days with nitrogen limitation. Five to six...... times during the exponential and stationary phases of each experimental bloom the bioavailability of DON was measured over 60 days together with DOC and oxygen consumption. The overall aim was to quantify remineralization of the added nitrate. The results showed that maximum 33 % of the added nitrate...

  10. Bioavailability of phytochemicals and its enhancement by drug delivery systems.

    Science.gov (United States)

    Aqil, Farrukh; Munagala, Radha; Jeyabalan, Jeyaprakash; Vadhanam, Manicka V

    2013-06-28

    Issues of poor oral bioavailability of cancer chemopreventives have hindered progress in cancer prevention. Novel delivery systems that modulate the pharmacokinetics of existing drugs, such as nanoparticles, cyclodextrins, niosomes, liposomes and implants, could be used to enhance the delivery of chemopreventive agents to target sites. The development of new approaches in prevention and treatment of cancer could encompass new delivery systems for approved and newly investigated compounds. In this review, we discuss some of the delivery approaches that have already made an impact by either delivering a drug to target tissue or increasing its bioavailability by many fold.

  11. Bioavailability of IgG Administered by the Subcutaneous Route

    OpenAIRE

    Berger, Melvin; Jolles, Stephen; Orange, Jordan S.; Sleasman, John W

    2013-01-01

    Purpose US licensing studies of subcutaneous IgG (SCIG) calculate dose adjustments necessary to achieve area under the curve (AUC) of serum IgG vs. time on SCIG that is non-inferior to that on intravenous IgG (IVIG), within the FDA-set limit of ±20 %. The results are interpreted as showing that different SCIGs differ in bioavailability. We used three approaches to determine if the bioavailabilities were actually different. Methods Dose adjustments and AUCs from published licensing studies wer...

  12. Relative Bioavailability and Bioaccessability and Speciation of Arsenic in Contaminated Soils

    Science.gov (United States)

    Background: Assessment of soil arsenic (As) bioavailability may profoundly affect the extent of remediation required at contaminated sites by improving human exposure estimates. Because small adjustments in soil As bioavailability estimates can significantly alter risk assessment...

  13. A review on the relationship between food structure, processing, and bioavailability.

    Science.gov (United States)

    Sensoy, Ilkay

    2014-01-01

    This review highlights the effects of processing and food matrix on bioaccessibility and bioavailability of functional components. Human digestive system is reviewed as an element in bioavailability. Methods for bioaccessibility and bioavailability determination are described. Information about the location of functional compounds in the tissue is presented to portray the matrix information. Research data on the effects of food matrix and processing on bioaccessibility and bioavailability are summarized. Finally, trends in the development of functional component delivery systems are included.

  14. Rapid persulfate oxidation predicts PAH bioavailability in soils and sediments

    NARCIS (Netherlands)

    Cuypers, M.P.; Grotenhuis, J.T.C.; Joziasse, J.; Rulkens, W.H.

    2000-01-01

    Persulfate oxidation was validated as a method to predict polycyclic aromatic hydrocarbon (PAH) bioavailability in soils and sediments. It was demonstrated for 14 field contaminated soils and sediments that residual PAH concentrations after a short (3 h) persulfate oxidation correspond well to resid

  15. BIOAVAILABILITY AND PHARMACOKINETICS OF NORFLOXACIN AFTER INTRAMUSCULAR ADMINISTRATION IN GOATS

    Directory of Open Access Journals (Sweden)

    WAJEEHA, F. H. KHAN AND I. JAVED

    2006-01-01

    Full Text Available Bioavailability and pharmacokinetics of two commercially available preparations of norfloxacin i.e. A (imported and B (locally prepared were determined in six healthy female goats after single intramuscular administration @ 5 mg/kg b.wt following crossover study design. The blood samples collected at 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8 and 12 hours postmedication were also analysed for drug concentration by microbiological assay. Results revealed that preparation A showed higher (p<0.05 plasma drug levels than the preparation B at 1, 3, 6 and 8 hours after medication. Among bioavailability parameters AUC (g.h/ml and relative bioavailability (F% were higher for preparation A than the preparation B, while other parameters did not differ between the two preparations. Similarly, various pharmacokinetic parameters did not show any statistical difference between preparation A and B. The study revealed comparable elimination kinetics but different bioavailability of two commercial preparations of norfloxacin. It is concluded from the study that for optimal dosage regimen of drugs, the bioequivalence studies and kinetic behavior of the drugs are of paramount importance.

  16. Differences in relative bioavailability of traditional Bangladeshi meal plans

    Science.gov (United States)

    Background: Iron (Fe) deficiency is the most common nutrient deficiency worldwide. Large intakes of micronutrient-poor staple crops, coupled with low intakes of highly bioavailable dietary Fe is a major cause of this deficiency. Objective: This study examined the Fe concentration and relative Fe ...

  17. Speciation and bio-availability of copper in Lake Tjeukemeer.

    NARCIS (Netherlands)

    Verweij, W.

    1991-01-01

    Chapter 1: introductionIn this thesis an account is given of a research project dealing with the chemical speciation and bioavailability of copper in Lake Tjeukemeer, a lake in the north of the Netherlands. The reason for the initiation of this project was a lack of knowledge about the speciation of

  18. [Bioavailability of erythromycin and colistin in calves (author's transl)].

    Science.gov (United States)

    Escoula, L; Coste, M; Larrieu, G

    1981-01-01

    Bioavailability of erythromycin and colistin was studied in plasma, ruminal liquid and nasal mucus after simultaneous injection by intraruminal or intramuscular route. After intramuscular injection, erythromycin was found in plasma and respiratory tract, colistin in plasma. After oral administration, only erythromycin was found in nasal cavity secretions but nitrogen metabolism and volatile fatty acid production were modified in rumen.

  19. Enhancement of Oral Bioavailability of Puerarin by Polybutylcyanoacrylate Nanoparticles

    Directory of Open Access Journals (Sweden)

    Lixia Zhao

    2011-01-01

    Full Text Available The interest using novel drug delivery systems to improve oral bioavailability of drug with poor solubility is increasing. In this study, a new oral delivery system, polybutylcyanoacrylate nanoparticles (PBCNs, was introduced to improve the oral bioavailability of puerarin (PUE. PUE-loaded PBCN was successfully prepared by anionic polymerization method. Characterization of PUE-loaded PBCN was evaluated with morphology, size, zeta potential, and in vitro release study. The PBCN loading PUE exhibited a spherical shape under transmission electron microscopy with an average size of 159.4 nm, and the zeta potential was −15.0 mV. The in vitro release of PUE-loaded PBCN showed an initial burst release followed by a sustained release. Physicochemical state of PUE in PBCN was investigated by differential scanning colorimetry, X-ray diffraction, and Fourier transform infrared spectroscopy. The results indicated that PUE in PBCN was in a noncrystalline state. The oral pharmacokinetic study in rats showed that the relative bioavailability of PUE-encapsulated PBCN to the crude PUE was more than 550%. It can be concluded that PBCN as an oral drug carrier can significantly improve the oral bioavailability of PUE.

  20. Relative bioavailability of arsenic contaminated soils in a mouse model

    Science.gov (United States)

    Exposure to As contaminated soils compels extensive soil cleanups so that human health risks are minimized. In order to improve exposure estimates and potentially reduce remediation costs, determination of the bioavailability of As in soils is needed. The objective of this study ...

  1. Fate and Bioavailability of Engineered Nanoparticles in Soils: A Review

    NARCIS (Netherlands)

    Cornelis, G.; Hund-Rinke, K.; Kuhlbusch, T.; Brink, van den N.W.; Nickel, C.

    2014-01-01

    Interactions within natural soils have often been neglected when assessing fate and bioavailability of engineered nanomaterials (ENM) in soils. This review combines patchwise ENM research using natural soils with the much wider literature on ENM performed in standard tests or on the fate of colloids

  2. Bioavailability of contaminants estimated from uptake rates into soil invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Straalen, N.M. van [Vrije Universiteit, Institute of Ecological Science, Department of Animal Ecology, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands)]. E-mail: nico.van.straalen@ecology.falw.vu.nl; Donker, M.H. [Vrije Universiteit, Institute of Ecological Science, Department of Animal Ecology, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands); Vijver, M.G. [Vrije Universiteit, Institute of Ecological Science, Department of Animal Ecology, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands); Gestel, C.A.M. van [Vrije Universiteit, Institute of Ecological Science, Department of Animal Ecology, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands)

    2005-08-15

    It is often argued that the concentration of a pollutant inside an organism is a good indicator of its bioavailability, however, we show that the rate of uptake, not the concentration itself, is the superior predictor. In a study on zinc accumulation and toxicity to isopods (Porcellio scaber) the dietary EC{sub 50} for the effect on body growth was rather constant and reproducible, while the internal EC{sub 50} varied depending on the accumulation history of the animals. From the data a critical value for zinc accumulation in P. scaber was estimated as 53 {mu}g/g/wk. We review toxicokinetic models applicable to time-series measurements of concentrations in invertebrates. The initial slope of the uptake curve is proposed as an indicator of bioavailability. To apply the dynamic concept of bioavailability in risk assessment, a set of representative organisms should be chosen and standardized protocols developed for exposure assays by which suspect soils can be evaluated. - Sublethal toxicity of zinc to isopods suggests that bioavailability of soil contaminants is best measured by uptake rates, not by body burdens.

  3. Saccharides enhance iron bioavailability to Southern Ocean phytoplankton

    NARCIS (Netherlands)

    Hassler, C.S.; Schoemann, V.; Nichols, C.M.; Butler, E.C.V.; Boyd, P.W.; Nichols, C.M.

    2011-01-01

    Iron limits primary productivity in vast regions of the ocean. Given that marine phytoplankton contribute up to 40% of global biological carbon fixation, it is important to understand what parameters control the availability of iron (iron bioavailability) to these organisms. Most studies on iron bio

  4. Uranium Speciation and Bioavailability in Aquatic Systems: An Overview

    Directory of Open Access Journals (Sweden)

    Scott J. Markich

    2002-01-01

    Full Text Available The speciation of uranium (U in relation to its bioavailability is reviewed for surface waters (fresh- and seawater and their sediments. A summary of available analytical and modeling techniques for determining U speciation is also presented. U(VI is the major form of U in oxic surface waters, while U(IV is the major form in anoxic waters. The bioavailability of U (i.e., its ability to bind to or traverse the cell surface of an organism is dependent on its speciation, or physicochemical form. U occurs in surface waters in a variety of physicochemical forms, including the free metal ion (U4+ or UO22+ and complexes with inorganic ligands (e.g., uranyl carbonate or uranyl phosphate, and humic substances (HS (e.g., uranyl fulvate in dissolved, colloidal, and/or particulate forms. Although the relationship between U speciation and bioavailability is complex, there is reasonable evidence to indicate that UO22+ and UO2OH+ are the major forms of U(VI available to organisms, rather than U in strong complexes (e.g., uranyl fulvate or adsorbed to colloidal and/or particulate matter. U(VI complexes with inorganic ligands (e.g., carbonate or phosphate and HS apparently reduce the bioavailability of U by reducing the activity of UO22+ and UO2OH+. The majority of studies have used the results from thermodynamic speciation modeling to support these conclusions. Time-resolved laser-induced fluorescence spectroscopy is the only analytical technique able to directly determine specific U species, but is limited in use to freshwaters of low pH and ionic strength. Nearly all of the available information relating the speciation of U to its bioavailability has been derived using simple, chemically defined experimental freshwaters, rather than natural waters. No data are available for estuarine or seawater. Furthermore, there are no available data on the relationship between U speciation and bioavailability in sediments. An understanding of this relationship has been

  5. The concept of iron bioavailability and its assessment.

    Science.gov (United States)

    Wienk, K J; Marx, J J; Beynen, A C

    1999-04-01

    In this review a broad overview of historical and current methods for the assessment of iron bioavailability was given. These methods can be divided into iron solubility studies, iron absorption studies, endpoint measures, and arithmetic models. The pros and cons of all methods were discussed. First, studies on in vitro and in vivo iron solubility have been described. The disadvantages of iron solubility include the impossibility of measuring absorption or incorporation of iron. Furthermore, only the solubility of nonheme iron, and not heme iron, can be studied. Second, we focused on iron absorption studies (either with the use of native iron, radioiron or stable iron isotopes), in which balance techniques, whole-body counting or postabsorption plasma iron measurements can be applied. In vitro determination of iron absorption using intestinal loops or cell lines, was also discussed in this part. As far as absorption studies using animals, duodenal loops, gut sacs or Caco-2 cells were concerned, the difficulty of extrapolating the results to the human situation seemed to be the major drawback. Chemical balance in man has been a good, but laborious and expensive, way to study iron absorption. Whole-body counting has the disadvantage of causing radiation exposure and it is based on a single meal. The measurement of plasma iron response did not seem to be of great value in determining nutritional iron bioavailability. The next part dealt with endpoint measures. According to the definition of iron bioavailability, these methods gave the best figure for it. In animals, the hemoglobin-repletion bioassay was most often used, whereas most studies in humans monitored the fate of radioisotopes or stable isotopes of iron in blood. Repletion bioassays using rats or other animals were of limited use because the accuracy of extrapolation to man is unknown. The use of the rat as a model for iron bioavailability seemed to be empirically based, and there were many reasons to

  6. 21 CFR 320.28 - Correlation of bioavailability with an acute pharmacological effect or clinical evidence.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Correlation of bioavailability with an acute..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE BIOAVAILABILITY AND BIOEQUIVALENCE REQUIREMENTS Procedures for Determining the Bioavailability or Bioequivalence of Drug Products §...

  7. 21 CFR 320.22 - Criteria for waiver of evidence of in vivo bioavailability or bioequivalence.

    Science.gov (United States)

    2010-04-01

    ... bioavailability or bioequivalence. 320.22 Section 320.22 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE BIOAVAILABILITY AND BIOEQUIVALENCE REQUIREMENTS Procedures for Determining the Bioavailability or Bioequivalence of Drug Products §...

  8. Iron bioavailability of maize hemoglobin in a Caco-2 cell culture model

    Science.gov (United States)

    Maize is an important staple crop in many parts of the world but has low iron bioavailability, in part due to its high phytate content. Hemoglobin is a form of iron that is highly bioavailable and its bioavailability is not inhibited by phytate. We hypothesize that maize hemoglobin is a highly bioav...

  9. Accumulation and bioavailability of dietary carotenoids in vegetable crops.

    Science.gov (United States)

    Kopsell, Dean A; Kopsell, David E

    2006-10-01

    Carotenoids are lipid-soluble pigments found in many vegetable crops that are reported to have the health benefits of cancer and eye disease reduction when consumed in the diet. Research shows that environmental and genetic factors can significantly influence carotenoid concentrations in vegetable crops, and that changing cultural management strategies could be advantageous, resulting in increased vegetable carotenoid concentrations. Improvements in vegetable carotenoid levels have been achieved using traditional breeding methods and molecular transformations to stimulate biosynthetic pathways. Postharvest and processing activities can alter carotenoid chemistry, and ultimately affect bioavailability. Bioavailability data emphasize the importance of carotenoid enhancement in vegetable crops and the need to characterize potential changes in carotenoid composition during cultivation, storage and processing before consumer purchase.

  10. Bioavailability of Glucosinolates and Their Breakdown Products: Impact of Processing

    Science.gov (United States)

    Barba, Francisco J.; Nikmaram, Nooshin; Roohinejad, Shahin; Khelfa, Anissa; Zhu, Zhenzhou; Koubaa, Mohamed

    2016-01-01

    Glucosinolates are a large group of plant secondary metabolites with nutritional effects, and are mainly found in cruciferous plants. After ingestion, glucosinolates could be partially absorbed in their intact form through the gastrointestinal mucosa. However, the largest fraction is metabolized in the gut lumen. When cruciferous are consumed without processing, myrosinase enzyme present in these plants hydrolyzes the glucosinolates in the proximal part of the gastrointestinal tract to various metabolites, such as isothiocyanates, nitriles, oxazolidine-2-thiones, and indole-3-carbinols. When cruciferous are cooked before consumption, myrosinase is inactivated and glucosinolates transit to the colon where they are hydrolyzed by the intestinal microbiota. Numerous factors, such as storage time, temperature, and atmosphere packaging, along with inactivation processes of myrosinase are influencing the bioavailability of glucosinolates and their breakdown products. This review paper summarizes the assimilation, absorption, and elimination of these molecules, as well as the impact of processing on their bioavailability. PMID:27579302

  11. [Bioequivalence and bioavailability after single administration of effervescent ranitidine tablets].

    Science.gov (United States)

    Hartmann, B; Schmieder, G; Tetzloff, W; Töberich, H

    1992-08-01

    An open two-way cross-over study in 12 healthy male volunteers was performed in order to determine the relative bioavailability of a 150 mg ranitidine (Zantic, CAS 66357-35-5) effervescent tablet sweetened with saccharine in comparison to the 150 mg standard ranitidine dispersible tablet (Trinkette). On two occasions separated by a wash-out period of 1 week volunteers received a single oral dose of both formulations. On each administration day blood samples were collected at predetermined time points in order to investigate the pharmacokinetic parameters. Single oral doses of ranitidine were very well tolerated by healthy male volunteers. The non-parametric 95% confidence intervals for AUC and Cmax were 87 to 116% and 84 to 107%, respectively. The relative bioavailability of the ranitidine effervescent tablet was 99% compared to the dispersible tablet. The mean of the Cmax ratio was 95%. The ranitidine effervescent tablet could thus be claimed to be bioequivalent to the dispersible tablet.

  12. Triple antioxidant SNEDDS formulation with enhanced oral bioavailability

    DEFF Research Database (Denmark)

    Tripathi, Shailja; Kushwah, Varun; Thanki, Kaushik;

    2016-01-01

    .3, respectively. DPPH scavenging assay showed comparable antioxidant activity of antioxidant loaded SNEDDS to free antioxidants combination. Furthermore, coumarin-6 loaded SNEDDS formulation showed rapid internalization within 1h of incubation by Caco-2 cells. Moreover, the pharmacokinetic studies in rats......The present study aimed to develop quercetin, resveratrol and genistein loaded self-nanoemulsifying drug delivery system (SNEDDS) by QbD approach in order to improve their oral bioavailability and antioxidant potential. The size and PDI of the optimized formulation were found to be ... for the optimized formulation and free antioxidant suspension were performed. SNEDDS have significantly increased the Cmax and area under curve (AUC) of all three antioxidants. The SNEDDS demonstrated ~4.27 fold enhancement in oral bioavailability of quercetin, ~1.5 fold in case of resveratrol and ~2.8 fold in case...

  13. Overview on gastroretentive drug delivery systems for improving drug bioavailability.

    Science.gov (United States)

    Lopes, Carla M; Bettencourt, Catarina; Rossi, Alessandra; Buttini, Francesca; Barata, Pedro

    2016-08-20

    In recent decades, many efforts have been made in order to improve drug bioavailability after oral administration. Gastroretentive drug delivery systems are a good example; they emerged to enhance the bioavailability and effectiveness of drugs with a narrow absorption window in the upper gastrointestinal tract and/or to promote local activity in the stomach and duodenum. Several strategies are used to increase the gastric residence time, namely bioadhesive or mucoadhesive systems, expandable systems, high-density systems, floating systems, superporous hydrogels and magnetic systems. The present review highlights some of the drugs that can benefit from gastroretentive strategies, such as the factors that influence gastric retention time and the mechanism of action of gastroretentive systems, as well as their classification into single and multiple unit systems.

  14. Bioavailability of capsaicin and its implications for drug delivery.

    Science.gov (United States)

    Rollyson, William D; Stover, Cody A; Brown, Kathleen C; Perry, Haley E; Stevenson, Cathryn D; McNees, Christopher A; Ball, John G; Valentovic, Monica A; Dasgupta, Piyali

    2014-12-28

    The dietary compound capsaicin is responsible for the "hot and spicy" taste of chili peppers and pepper extracts. It is a valuable pharmacological agent with several therapeutic applications in controlling pain and inflammation. Emerging studies show that it displays potent anti-tumor activity in several human cancers. On a more basic research level, capsaicin has been used as a ligand to activate several types of ion-channel receptors. The pharmacological activity of capsaicin-like compounds is dependent on several factors like the dose, the route of administration and most importantly on its concentration at target tissues. The present review describes the current knowledge involving the metabolism and bioavailability of capsaicinoids in rodents and humans. Novel drug delivery strategies used to improve the bioavailability and therapeutic index of capsaicin are discussed in detail. The generation of novel capsaicin-mimetics and improved drug delivery methods will foster the hope of innovative applications of capsaicin in human disease.

  15. The role of H2S bioavailability in endothelial dysfunction

    Science.gov (United States)

    Wang, Rui; Szabo, Csaba; Ichinose, Fumito; Ahmed, Asif; Whiteman, Matthew; Papapetropoulos, Andreas

    2015-01-01

    Endothelial dysfunction reflects pathophysiological changes in the phenotype and functions of endothelial cells that result from and/or contribute to a plethora of cardiovascular diseases. Here we review the role of hydrogen sulfide (H2S) in the pathogenesis of endothelial dysfunction, one of the fastest advanced and hottest research topics. Conventionally treated as an environment pollutant, H2S is also produced in endothelial cells and participates in the fine regulation of endothelial integrity and functions. Disturbed H2S bioavailability has been suggested to be a novel indicator of the progress and prognosis of endothelial dysfunction. Endothelial dysfunction appears to exhibit in different forms in different pathologies but therapeutics aimed at remedying the altered H2S bioavailability may benefit all. PMID:26071118

  16. Improving Bioavailability of Naftopidil in Dogs by Using Bioadhesion

    Institute of Scientific and Technical Information of China (English)

    DingJinsong; JiangXuehua

    2001-01-01

    To improve the bioavailability of naftopidil, bioadhesive sustained-release capsules and nonbioadhesive capsules were prepared. Bioadhesive polymers such as hydroxypropyl methylcellulose (HPMC) and Carbopol 934 (CP 934) were used in the bioadhesive capsules formulations. Naftopidil capsule and two formulations of bioadhesive sustained-release capsules (I and II) were respectively given to five healthy male dogs in an open randomized cross-over test. The naftopidil concentrations in plasma were determined by a newly developed HPLC method. The pharmacokinetic parameters and the relative bioavailability were measured. The AUC0→24, Cmax and Tmax,of non-bioadhesive naftopidil capsules were 3494.7±466.47 h.ng.mL-1, 697.48±94.22 ng-mL-1 and 1.15±40.49 h. These pharmacokinetic parameters of bioadhesive sustained-release capsules I and II were 4618.46±316.68 h-ng-mL-1 and 4746.44±317.22 h.ng.mL-1, 468.59±61.25 ng-mL-1 and 512.00±72.29 ng.mL-1, both 4.0±0.71 h respectively. Results from statistical analysis showed that there were significant differences between the two bioadhesive formulations and the non-bioadhesive one in AUC0→24, Cmax and Tmax The relative bioavailability of the two bioadhesive sustainedrelease capsules were respectively 133.40±12.72% and 137.53±17.49% when compared with non-bioadhesive capsules. The bioavailability of naftopidil in dogs was improved hy using bioadhesion.

  17. Rumen Microorganisms Decrease Bioavailability of Inorganic Selenium Supplements.

    Science.gov (United States)

    Galbraith, M L; Vorachek, W R; Estill, C T; Whanger, P D; Bobe, G; Davis, T Z; Hall, J A

    2016-06-01

    Despite the availability of selenium (Se)-enriched trace mineral supplements, we have observed low Se status in cattle and sheep offered traditional inorganic Se supplements. Reasons for this may include inadequate intake or low bioavailability of inorganic Se sources. The objective of this study was to determine whether rumen microorganisms (RMO) alter the bioavailability of Se sources commonly used in Se supplements. Rumen microorganisms were isolated from ewes (n = 4) and incubated ex vivo with no Se (control), with inorganic Na selenite or Na selenate, or with organic selenomethionine (SeMet). Total Se incorporated into RMO and the amount of elemental Se formed were determined under equivalent conditions. Incorporation of Se from Na selenite, Na selenate, or SeMet into RMO was measured as fold change compared with control (no added Se). Incorporation of Se into microbial mass was greater for SeMet (13.2-fold greater than no-Se control) compared with inorganic Se supplements (P = 0.02); no differences were observed between inorganic Na selenate (3.3-fold greater than no-Se control) and Na selenite (3.5-fold greater than no-Se control; P = 0.97). Formation of non-bioavailable, elemental Se was less for RMO incubated with SeMet compared with inorganic Se sources (P = 0.01); no differences were observed between Na selenate and Na selenite (P = 0.09). The clinical importance of these results is that the oral bioavailability of organic SeMet should be greater compared with inorganic Se sources because of greater RMO incorporation of Se and decreased formation of elemental Se by RMO.

  18. Pharmacokinetics and bioavailability study of neoline in Beagle dogs.

    Science.gov (United States)

    Gong, Xiao-hong; Zhao, Meng-jie; Yuan, An; Li, Yan; Xiong, Liang; Peng, Cheng; Li, Yun-xia

    2015-07-01

    This paper is aim to investigate the pharmacokinetics and absolute bioavailability of neoline in Beagle dogs, and provide a theoretical basis for further study. Ethyl acetate was used for liquid-liquid extracting after 10% ammonia alkalizing. The method of UPLC-Q-TOF-MS was established for the determination of neoline plasma concentrations. Beagle dogs were orally or intravenously administered with neoline for pharmacokinetic and absolute bioavailability study. Good linear relationship of neoline was found over the range of 0.1-4 mg x L(-1) (R2 = 0.9982) and 2-100 microg x L(-1) (R2 = 0.9945). Intra-and inter-day precision, expressed as the relativestandard (RSD) were less than 5.0%. Accuracy, expressed as the relative error (RE) was within 90.0%-115%. The recovery of neoline in dog plasma was more than 80%. After 6 mg x kg(-1) for ig and 1 mg x kg(-1) for iv administration of neoline, the main pharmacokinetic parameters were analyzed with Winnonlin software. t(1/2) were (313.88 +/- 63.18), (236.33 +/- 229.84) min, and AUC(0-infinity) were (58,027.40 +/- 14,132.69), (473,578.02 +/- 82,333.08) min x microg x L(-1) for ig and iv administration respectively. The absolute bioavail ability was (73.15 +/- 10.29) %. The method of UPLC-Q-TOF-MS described in the report was sensitive, reliable and specific, and suitable for pharmacokinetic study of neoline in Beagle dog. The high absolute bioavailability of neoline in dog suggested good absorption of neline which was worth of further investigation.

  19. Eudragit nanoparticles containing genistein: formulation, development, and bioavailability assessment

    Directory of Open Access Journals (Sweden)

    Tang J

    2011-10-01

    Full Text Available Jingling Tang2, Na Xu1,2, Hongyu Ji1, Hongmei Liu1, Zhiyong Wang1, Linhua Wu1,2 1Department of Pharmacy, the Second Affiliated Hospital of Harbin Medical University, Key Laboratory of College in Heilongjiang Province; 2Department of Pharmaceutics, School of Pharmacy, Harbin Medical University, Harbin, China Background: Genistein, one of the major isoflavones, has received great attention as a phytoestrogen and potential cancer chemoprevention agent. However, the dissolution and bioavailability of genistein from solid oral preparations is low due to its poor water solubility. Methods: In order to improve the oral bioavailability of genistein, genistein nanoparticles were prepared by the nanoprecipitation technique using Eudragit® E100 as carriers and an optimized formulation of mass ratio (genistein:Eudragit E100, 1:10. The mean particle size of genistein nanoparticles was approximately 120 nm when diluted 100 times with distilled water. The drug-loaded nanoparticles were spherical on observation by transmission electric microscopy. Results: Encapsulation efficiency and drug loading of the genistein nanoparticles were approximately 50.61% and 5.02%, respectively. Release of drug from the genistein nanoparticles was two times greater than that from the conventional capsules. After administration of genistein suspension or genistein nanoparticles at a single dose of 100 mg/kg to fasted rats, the relative bioavailability of genistein from the nanoparticles compared with the reference suspension was 241.8%. Conclusion: These results suggested that a nanoparticle system is a potentially promising formulation for the efficient delivery of poorly water-soluble drugs by oral administration. Keywords: bioavailability, dissolution, genistein, nanoparticles, nanoprecipitation technique

  20. The bioavailability of red ginseng extract fermented by Phellinus linteus.

    Science.gov (United States)

    Ryu, Jae Sik; Lee, Hyun Jung; Bae, Song Hwan; Kim, Sun Young; Park, Yooheon; Suh, Hyung Joo; Jeong, Yoon Hwa

    2013-03-01

    For the improvement of ginsenoside bioavailability, the ginsenosides of fermented red ginseng by Phellinus linteus (FRG) were examined with respect to bioavailability and physiological activity. The polyphenol content of FRG (19.14±0.50 mg/g) was significantly higher (p<0.05) compared with that of non-fermented red ginseng (NFRG, 11.31±1.15 mg/g). The antioxidant activities in FRG, such as 2,2'-diphenyl-1-picrylhydrazyl, 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid, and ferric reducing antioxidant power, were significantly higher (p<0.05) than those in NFRG. The HPLC analysis results showed that the FRG had a high level of ginsenoside metabolites. The total ginsenoside contents in NFRG and FRG were 41.65±1.53 mg/g and 50.12±1.43 mg/g, respectively. However, FRG had a significantly higher content (33.90±0.97 mg/g) of ginsenoside metabolites (Rg3, Rg5, Rk1, compound K, Rh1, F2, and Rg2) compared with NFRG (14.75±0.46 mg/g). The skin permeability of FRG was higher than that of NFRG using Franz diffusion cell models. In particular, after 3 h, the skin permeability of FRG was significantly higher (p<0.05) than that of NFRG. Using a rat everted intestinal sac model, FRG showed a high transport level compared with NFRG after 1 h. FRG had dramatically improved bioavailability compared with NFRG as indicated by skin permeation and intestinal permeability. The significantly greater bioavailability of FRG may have been due to the transformation of its ginsenosides by fermentation to more easily absorbable forms (ginsenoside metabolites).

  1. The bioavailability of colloidal phosphorus to freshwater algae

    OpenAIRE

    2014-01-01

    The eutrophication of freshwaters is a major environmental concern in developed countries and is often attributed to excessive P fertilizer application. However, the eutrophication risk depends strongly on P bioavailability, which in turn depends on P speciation. Colloidal P species, e.g. P associated with colloidal Fe and Al oxyhydroxides, are included in routine colorimetric measurements of the available P fraction as “molybdate reactive P”, but the availability of this colloidal P fraction...

  2. Hologram QSAR model for the prediction of human oral bioavailability.

    Science.gov (United States)

    Moda, Tiago L; Montanari, Carlos A; Andricopulo, Adriano D

    2007-12-15

    A drug intended for use in humans should have an ideal balance of pharmacokinetics and safety, as well as potency and selectivity. Unfavorable pharmacokinetics can negatively affect the clinical development of many otherwise promising drug candidates. A variety of in silico ADME (absorption, distribution, metabolism, and excretion) models are receiving increased attention due to a better appreciation that pharmacokinetic properties should be considered in early phases of the drug discovery process. Human oral bioavailability is an important pharmacokinetic property, which is directly related to the amount of drug available in the systemic circulation to exert pharmacological and therapeutic effects. In the present work, hologram quantitative structure-activity relationships (HQSAR) were performed on a training set of 250 structurally diverse molecules with known human oral bioavailability. The most significant HQSAR model (q(2)=0.70, r(2)=0.93) was obtained using atoms, bond, connection, and chirality as fragment distinction. The predictive ability of the model was evaluated by an external test set containing 52 molecules not included in the training set, and the predicted values were in good agreement with the experimental values. The HQSAR model should be useful for the design of new drug candidates having increased bioavailability as well as in the process of chemical library design, virtual screening, and high-throughput screening.

  3. Estimation of bioavailability of metals from drilling mud barite.

    Science.gov (United States)

    Neff, Jerry M

    2008-04-01

    Drilling mud and associated drill cuttings are the largest volume wastes associated with drilling of oil and gas wells and often are discharged to the ocean from offshore drilling platforms. Barite (BaSO4) often is added as a weighting agent to drilling muds to counteract pressure in the geologic formations being drilled, preventing a blowout. Some commercial drilling mud barites contain elevated (compared to marine sediments) concentrations of several metals. The metals, if bioavailable, may harm the local marine ecosystem. The bioavailable fraction of metals is the fraction that dissolves from the nearly insoluble, solid barite into seawater or sediment porewater. Barite-seawater and barite-porewater distribution coefficients (Kd) were calculated for determining the predicted environmental concentration (PEC; the bioavailable fraction) of metals from drilling mud barite in the water column and sediments, respectively. Values for Kdbarite-seawater and Kdbarite-porewater were calculated for barium, cadmium, chromium, copper, mercury, lead, and zinc in different grades of barite. Log Kdbarite-seawater values were higher (solubility was lower) for metals in the produced water plume than log Kdbarite-porewater values for metals in sediments. The most soluble metals were cadmium and zinc and the least soluble were mercury and copper. Log Kd values can be used with data on concentrations of metals in barite and of barite in the drilling mud-cuttings plume and in bottom sediments to calculate PECseawater and PECsediment.

  4. Assessment of the bioavailability of cadmium in Jamaican soils.

    Science.gov (United States)

    Spence, Adrian; Hanson, Richard E; Grant, Charles N; Hoo Fung, Leslie; Rattray, Robin

    2014-07-01

    Extraordinary geogenic concentrations of cadmium (Cd) have been reported for some Jamaican soils. However, the bioavailability of the metal in these soils remains unknown. Here, the bioavailability of Cd in selected Jamaican soils was investigated through the determination of total and sequentially extractable concentrations in paired soil-plant (yam; Dioscorea sp.) samples (n = 24), using neutron activation analysis and atomic absorption spectroscopy as primary analytical techniques. Our results indicate that total soil Cd varied widely (2.2-148.7 mg kg(-1)), and on average, total extractable Cd accounted for ~55 % of the total soil Cd. The exchangeable and oxidizable species averaged 1.5 and 6.4 % of the total Cd, respectively, and, based on Spearman analysis, are the best predictors of yam Cd. There is also good evidence to suggest that variation in the bioavailability of the metal is in part controlled by the geochemical characteristics of the soils analyzed and is best explained by pH, cation exchange capacity (CEC) and organic matter content (% LOI).

  5. Excipient Nanoemulsions for Improving Oral Bioavailability of Bioactives

    Directory of Open Access Journals (Sweden)

    Laura Salvia-Trujillo

    2016-01-01

    Full Text Available The oral bioavailability of many hydrophobic bioactive compounds found in natural food products (such as vitamins and nutraceuticals in fruits and vegetables is relatively low due to their low bioaccessibility, chemical instability, or poor absorption. Most previous research has therefore focused on the design of delivery systems to incorporate isolated bioactive compounds into food products. However, a more sustainable and cost-effect approach to enhancing the functionality of bioactive compounds is to leave them within their natural environment, but specifically design excipient foods that enhance their bioavailability. Excipient foods typically do not have functionality themselves but they have the capacity to enhance the functionality of nutrients present in natural foods by altering their bioaccessibility, absorption, and/or chemical transformation. In this review article we present the use of excipient nanoemulsions for increasing the bioavailability of bioactive components from fruits and vegetables. Nanoemulsions present several advantages over other food systems for this application, such as the ability to incorporate hydrophilic, amphiphilic, and lipophilic excipient ingredients, high physical stability, and rapid gastrointestinal digestibility. The design, fabrication, and application of nanoemulsions as excipient foods will therefore be described in this article.

  6. Nicotianamine, a novel enhancer of rice iron bioavailability to humans.

    Directory of Open Access Journals (Sweden)

    Luqing Zheng

    Full Text Available BACKGROUND: Polished rice is a staple food for over 50% of the world's population, but contains little bioavailable iron (Fe to meet human needs. Thus, biofortifying the rice grain with novel promoters or enhancers of Fe utilization would be one of the most effective strategies to prevent the high prevalence of Fe deficiency and iron deficiency anemia in the developing world. METHODOLOGY/PRINCIPAL FINDINGS: We transformed an elite rice line cultivated in Southern China with the rice nicotianamine synthase gene (OsNAS1 fused to a rice glutelin promoter. Endosperm overexpression of OsNAS1 resulted in a significant increase in nicotianamine (NA concentrations in both unpolished and polished grain. Bioavailability of Fe from the high NA grain, as measured by ferritin synthesis in an in vitro Caco-2 cell model that simulates the human digestive system, was twice as much as that of the control line. When added at 1:1 molar ratio to ferrous Fe in the cell system, NA was twice as effective when compared to ascorbic acid (one of the most potent known enhancers of Fe bioavailability in promoting more ferritin synthesis. CONCLUSIONS: Our data demonstrated that NA is a novel and effective promoter of iron utilization. Biofortifying polished rice with this compound has great potential in combating global human iron deficiency in people dependent on rice for their sustenance.

  7. Food microstructure affects the bioavailability of several nutrients.

    Science.gov (United States)

    Parada, J; Aguilera, J M

    2007-03-01

    There is an increased interest in the role that some nutrients may play in preventing or ameliorating the effect of major diseases (for example, some types of cancer, cardiovascular diseases, eye disorders, among others). In this respect, the bioavailability or the proportion of an ingested nutrient that is made available (that is, delivered to the bloodstream) for its intended mode of action is more relevant than the total amount present in the original food. Disruption of the natural matrix or the microstructure created during processing may influence the release, transformation, and subsequent absorption of some nutrients in the digestive tract. Alternatively, extracts of bioactive molecules (for example, nutraceuticals) and beneficial microorganisms may be protected during their transit in the digestive system to the absorption sites by encapsulation in designed matrices. This review summarizes relevant in vivo and in vitro methods used to assess the bioavailability of some nutrients (mostly phytochemicals), types of microstructural changes imparted by processing and during food ingestion that are relevant in matrix-nutrient interactions, and their effect on the bioavailability of selected nutrients.

  8. Oral bioavailability of heavy metals and organic compounds from soil ; too complicated to absorb? An inventarisation of factors affecting bioavailability of environmental contaminants from soil

    NARCIS (Netherlands)

    Sips AJAM; Eijkeren JCH van; LBO

    1996-01-01

    Bioavailability plays an important role in risk assessment of environmental contaminants from soil. It is one of the determinants in the assessment of intervention values. In present risk assessment, bioavailability from soil is supposed to be 100% due to a paucity of reliable information. However,

  9. In vivo and in vitro testing for selenium and selenium compounds bioavailability assessment in foodstuff.

    Science.gov (United States)

    Moreda-Piñeiro, Jorge; Moreda-Piñeiro, Antonio; Bermejo-Barrera, Pilar

    2017-03-04

    The assessment of selenium and selenium species bioavailability in foodstuff is of special concern on the context of human nutrition. In vivo (human and animal), and in vitro tests are important approaches for estimating the bioavailability of toxic and essential compounds to humans. An overview on in vivo and in vitro bioavailability assays for releasing selenium and selenium species in foodstuffs is summarized. Se and Se species content in a foodstuff critically influence Se bioavailability and bioactivity to humans and animals. Se bioavailability is affected by foodstuff-matrix major composition and minor components. Foodstuffs processing and/or treatments could enhancement or decrease Se bioavailability. Experimental conditions such as the selection of healthy status of examined people (in in vivo humans approaches), the selection of animal model (in vivo animals approaches), or the selection of GI conditions (in in vitro tests) could determines the results. Thus, international standardized protocol for in vivo and in vitro approaches assessment is mandatory.

  10. Bioavailabilities of quercetin-3-glucoside and quercetin-4'-glucoside do not differ in humans

    OpenAIRE

    Olthof, M.; Hollman, P.C.H.; Vree, T. B.; Katan, M.B.

    2000-01-01

    The flavonoid quercetin is an antioxidant which occurs in foods mainly as glycosides. The sugar moiety in quercetin glycosides affects their bioavailability in humans. Quercetin-3-rutinoside is an important form of quercetin in foods, but its bioavailability in humans is only 20␘f that of quercetin-4'-glucoside. Quercetin-3-rutinoside can be transformed into quercetin-3-glucoside by splitting off a rhamnose molecule. We studied whether this 3-glucoside has the same high bioavailability as the...

  11. Iron Bioavailability and Provitamin A from Sweet Potato- and Cereal-Based Complementary Foods

    OpenAIRE

    Tatiana Christides; Francis Kweku Amagloh; Jane Coad

    2015-01-01

    Iron and vitamin A deficiencies in childhood are public health problems in the developing world. Introduction of cereal-based complementary foods, that are often poor sources of both vitamin A and bioavailable iron, increases the risk of deficiency in young children. Alternative foods with higher levels of vitamin A and bioavailable iron could help alleviate these micronutrient deficiencies. The objective of this study was to compare iron bioavailability of β-carotene-rich sweet potato-based ...

  12. Assessing the relative bioavailability of DOC in regional groundwater systems

    Science.gov (United States)

    Chapelle, Francis H.; Bradley, Paul M.; Journey, Celeste; McMahon, Peter B.

    2013-01-01

    It has been hypothesized that the degree to which a hyperbolic relationship exists between concentrations of dissolved organic carbon (DOC) and dissolved oxygen (DO) in groundwater may indicate the relative bioavailability of DOC. This hypothesis was examined for 73 different regional aquifers of the United States using 7745 analyses of groundwater compiled by the National Water Assessment (NAWQA) program of the U.S. Geological Survey. The relative reaction quotient (RRQ), a measure of the curvature of DOC concentrations plotted versus DO concentrations and regressed to a decaying hyperbolic equation, was used to assess the relative bioavailability of DOC. For the basalt aquifer of Oahu, Hawaii, RRQ values were low (0.0013 mM−2), reflecting a nearly random relationship between DOC and DO concentrations. In contrast, on the island of Maui, treated sewage effluent injected into a portion of the basalt aquifer resulted in pronounced hyperbolic DOC-DO behavior and a higher RRQ (142 mM−2). RRQ values for the 73 aquifers correlated positively with mean concentrations of ammonia, dissolved iron, and manganese, and correlated negatively with mean pH. This indicates that greater RRQ values are associated with greater concentrations of the final products of microbial reduction reactions. RRQ values and DOC concentrations were negatively correlated with the thickness of the unsaturated zone (UNST) and depth to the top of the screened interval. Finally, RRQ values were positively correlated with mean annual precipitation (MAP), and the highest observed RRQ values were associated with aquifers receiving MAP rates ranging between 900 and 1300 mm/year. These results are uniformly consistent with the hypothesis that the hyperbolic behavior of DOC-DO plots, as quantified by the RRQ metric, can be an indicator of relative DOC bioavailability in groundwater systems.

  13. An overview of BORIS: Bioavailability of Radionuclides in Soils

    Energy Technology Data Exchange (ETDEWEB)

    Tamponnet, C. [Institute of Radioprotection and Nuclear Safety, DEI/SECRE, CADARACHE, B.P. 1, 13108 Saint-Paul-lez-Durance, Cedex (France)], E-mail: christian.tamponnet@irsn.fr; Martin-Garin, A.; Gonze, M.-A. [Institute of Radioprotection and Nuclear Safety, DEI/SECRE, CADARACHE, B.P. 1, 13108 Saint-Paul-lez-Durance, Cedex (France); Parekh, N. [Center for Ecology and Hydrology, Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Vallejo, R.; Sauras-Yera, T.; Casadesus, J. [Department of Plant Biology, University of Barcelona, 08028 Barcelona (Spain); Plassard, C.; Staunton, S. [INRA, UMR Rhizosphere and Symbiosis, Place Viala, 34060 Montpellier (France); Norden, M. [Swedish Radiation Protection Institute, 171 16 Stockholm (Sweden); Avila, R. [Facilia AB, Valsgaerdevaegen 12, 168 53 Bromma, Stockholm (Sweden); Shaw, G. [Division of Agricultural and Environmental Sciences University Park, Nottingham NG7 2RD (United Kingdom)

    2008-05-15

    The ability to predict the consequences of an accidental release of radionuclides relies mainly on the level of understanding of the mechanisms involved in radionuclide interactions with different components of agricultural and natural ecosystems and their formalisation into predictive models. Numerous studies and databases on contaminated agricultural and natural areas have been obtained, but their use to enhance our prediction ability has been largely limited by their unresolved variability. Such variability seems to stem from incomplete knowledge about radionuclide interactions with the soil matrix, soil moisture, and biological elements in the soil and additional pollutants, which may be found in such soils. In the 5th European Framework Programme entitled Bioavailability of Radionuclides in Soils (BORIS), we investigated the role of the abiotic (soil components and soil structure) and biological elements (organic compounds, plants, mycorrhiza, and microbes) in radionuclide sorption/desorption in soils and radionuclide uptake/release by plants. Because of the importance of their radioisotopes, the bioavailability of three elements, caesium, strontium, and technetium has been followed. The role of one additional non-radioactive pollutant (copper) has been scrutinised in some cases. Role of microorganisms (e.g., K{sub d} for caesium and strontium in organic soils is much greater in the presence of microorganisms than in their absence), plant physiology (e.g., changes in plant physiology affect radionuclide uptake by plants), and the presence of mycorrhizal fungi (e.g., interferes with the uptake of radionuclides by plants) have been demonstrated. Knowledge acquired from these experiments has been incorporated into two mechanistic models CHEMFAST and BIORUR, specifically modelling radionuclide sorption/desorption from soil matrices and radionuclide uptake by/release from plants. These mechanistic models have been incorporated into an assessment model to enhance

  14. Improvement of fluvastatin bioavailability by loading on nanostructured lipid carriers

    Directory of Open Access Journals (Sweden)

    El-Helw AR

    2015-09-01

    Full Text Available Abdel-Rahim M El-Helw, Usama A FahmyDepartment of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi ArabiaAbstract: The aim of this study is to prepare fluvastatin nanostructured lipid carriers (FLV-NLCs in order to find an innovative way to alleviate FLV-associated disadvantages. The limitations include poor solubility and extensive first-pass metabolism, resulting in low (30% bioavailability and short elimination half-life (1–3 hours. FLV-NLCs were prepared by hot emulsification–ultrasonication method. Ten runs were created by three-level factorial design (32 to optimize FLV-NLCs formulation process. In this study, two factors, four responses, and three-level factorial design were endorsed. The studied variables were lipid:oil ratio (X1 and sonication time (X2. However, the responses parameter determined the particle size (Y1, nm, entrapment efficiency percent (EE%, Y2, particles zeta potential (Y3, and 80% of the drug release after 24 hours (X4. Furthermore, stability and in vivo pharmacokinetics were studied in rats. The optimized consisted formula had an average particle size of 165 nm with 75.32% entrapment efficiency and 85.32% of drug released after 24 hours, demonstrating a sustaining drug release over 24 hours. An in vivo pharmacokinetic study revealed enhanced bioavailability by >2.64-fold, and the mean residence time was longer than that of FLV. We concluded that NLCs could be promising carriers for sustained/prolonged FLV release with enhanced oral bioavailability.Keywords: factorial design, nano-vesicles, hyperlipidemia, statins

  15. Nanosuspension for enhancement of oral bioavailability of felodipine

    Science.gov (United States)

    Sahu, Bhanu P.; Das, Malay K.

    2013-01-01

    The oral bioavailability of poorly water soluble drug can be improved using nanosuspension. Nanosuspensions are fine dispersion of uniform-sized solid particles in an aqueous vehicle. The present work is aimed at the formulation and evaluation of nanosuspension of felodipine, a poorly water soluble antihypertensive drug. The nanosuspension of felodipine may increase the dissolution rate of drug to improve its oral bioavailability. The nanosuspensions were prepared by nanoprecipitation alone and in combination with ultrasonnication method using ethanol as solvent and water as antisolvent. The prepared nanosuspensions were characterised for particle size, zeta potential, polydispersity index, Scanning electron microscopy (SEM), Differential scanning calorimetry (DSC), X-ray diffraction (XRD) pattern and release behaviour. The effect of variable concentration of drug and stabiliser, ultrasonnication, and solvent to antisolvent ratio on the physical, morphological and dissolution properties of felodipine were studied. The average particle size of felodipine nanoparticles was found to be in the range of 60-330 nm. It was further confirmed by SEM photograph. The particle size varies with increase in concentration of drug and stabiliser. The preparations showed negative zeta potential and polydispersity index in the range of 0.3-0.8. DSC and XRD studies indicated that the crystallinity of precipitated felodipine nanoparticles was markedly lowered than the pure drug. The dissolution of prepared felodipine nanoparticles markedly increased as compared to the original drug. The dissolution profiles of nanosuspension formulation showed up to 79.67 % release in 4 h. It may be concluded that the nanoprecipitation with ultrasonnication have potential to formulate homogenous nanosuspensions with uniform-sized stable nanoparticles of felodipine. The prepared nanosuspension showed enhanced dissolution which may lead to enhanced oral bioavailability of felodipine.

  16. Increasing intracellular bioavailable copper selectively targets prostate cancer cells.

    Science.gov (United States)

    Cater, Michael A; Pearson, Helen B; Wolyniec, Kamil; Klaver, Paul; Bilandzic, Maree; Paterson, Brett M; Bush, Ashley I; Humbert, Patrick O; La Fontaine, Sharon; Donnelly, Paul S; Haupt, Ygal

    2013-07-19

    The therapeutic efficacy of two bis(thiosemicarbazonato) copper complexes, glyoxalbis[N4-methylthiosemicarbazonato]Cu(II) [Cu(II)(gtsm)] and diacetylbis[N4-methylthiosemicarbazonato]Cu(II) [Cu(II)(atsm)], for the treatment of prostate cancer was assessed in cell culture and animal models. Distinctively, copper dissociates intracellularly from Cu(II)(gtsm) but is retained by Cu(II)(atsm). We further demonstrated that intracellular H2gtsm [reduced Cu(II)(gtsm)] continues to redistribute copper into a bioavailable (exchangeable) pool. Both Cu(II)(gtsm) and Cu(II)(atsm) selectively kill transformed (hyperplastic and carcinoma) prostate cell lines but, importantly, do not affect the viability of primary prostate epithelial cells. Increasing extracellular copper concentrations enhanced the therapeutic capacity of both Cu(II)(gtsm) and Cu(II)(atsm), and their ligands (H2gtsm and H2atsm) were toxic only toward cancerous prostate cells when combined with copper. Treatment of the Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) model with Cu(II)(gtsm) (2.5 mg/kg) significantly reduced prostate cancer burden (∼70%) and severity (grade), while treatment with Cu(II)(atsm) (30 mg/kg) was ineffective at the given dose. However, Cu(II)(gtsm) caused mild kidney toxicity in the mice, associated primarily with interstitial nephritis and luminal distention. Mechanistically, we demonstrated that Cu(II)(gtsm) inhibits proteasomal chymotrypsin-like activity, a feature further established as being common to copper-ionophores that increase intracellular bioavailable copper. We have demonstrated that increasing intracellular bioavailable copper can selectively kill cancerous prostate cells in vitro and in vivo and have revealed the potential for bis(thiosemicarbazone) copper complexes to be developed as therapeutics for prostate cancer.

  17. Potential bioavailability of mercury in humus-coated clay minerals.

    Science.gov (United States)

    Zhu, Daiwen; Zhong, Huan

    2015-10-01

    It is well-known that both clay and organic matter in soils play a key role in mercury biogeochemistry, while their combined effect is less studied. In this study, kaolinite, vermiculite, and montmorillonite were coated or not with humus, and spiked with inorganic mercury (IHg) or methylmercury (MeHg). The potential bioavailability of mercury to plants or deposit-feeders was assessed by CaCl2 or bovine serum albumin (BSA) extraction. For uncoated clay, IHg or MeHg extraction was generally lower in montmorillonite, due to its greater number of functional groups. Humus coating increased partitioning of IHg (0.5%-13.7%) and MeHg (0.8%-52.9%) in clay, because clay-sorbed humus provided more strong binding sites for mercury. Furthermore, humus coating led to a decrease in IHg (3.0%-59.8% for CaCl2 and 2.1%-5.0% for BSA) and MeHg (8.9%-74.6% for CaCl2 and 0.5%-8.2% for BSA) extraction, due to strong binding between mercury and clay-sorbed humus. Among various humus-coated clay particles, mercury extraction by CaCl2 (mainly through cation exchange) was lowest in humus-coated vermiculite, explained by the strong binding between humus and vermiculite. The inhibitory effect of humus on mercury bioavailability was also evidenced by the negative relationship between mercury extraction by CaCl2 and mercury in the organo-complexed fraction. In contrast, extraction of mercury by BSA (principally through complexation) was lowest in humus-coated montmorillonite. This was because BSA itself could be extensively sorbed onto montmorillonite. Results suggested that humus-coated clay could substantially decrease the potential bioavailability of mercury in soils, which should be considered when assessing risk in mercury-contaminated soils.

  18. Chemical measures of bioavailability/bioaccessibility of PAHs in soil: fundamentals to application.

    Science.gov (United States)

    Riding, Matthew J; Doick, Kieron J; Martin, Francis L; Jones, Kevin C; Semple, Kirk T

    2013-10-15

    Risk assessment and remediation of contaminated land is inherently dependent on the contaminants present and their availability for interaction with soil biota. An ever-growing body of evidence suggests that current regulatory procedures over-estimate the 'true' fraction available to biota. Thus, a procedure that predicts the 'bioavailable fraction' would be useful for predicting 'actual' exposure limits and provide a more relevant basis for risk assessment. The aim of this paper is to address several important questions: "How should bioavailability be defined?" "What factors affect bioavailability measurement?" "To what extent have existing protocols measured bioavailability?" "What is actually measured by chemical techniques purported to determine bioavailability?" We offer two definitions (namely 'bioavailability' and 'bioaccessibility') and review commonly employed chemical extraction techniques to measure putative bioavailability. Relative advantages and disadvantages of the techniques are highlighted to elucidate underlying factors for the wide range of conclusions observed in the literature. Although the concept of bioavailability is implicit to contaminated land risk assessment and remediation, explicit reference to and use of adjustment factors is rare amongst regulatory bodies and remediators. Use of chemical determinants for bioavailability, applicable within current legislation and due consideration to inherent variability, are proposed and barriers to their implementation discussed.

  19. Using deuterated PAH amendments to validate chemical extraction methods to predict PAH bioavailability in soils

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Eyles, Jose L., E-mail: j.l.gomezeyles@reading.ac.uk [University of Reading, School of Human and Environmental Sciences, Soil Research Centre, Reading, RG6 6DW Berkshire (United Kingdom); Collins, Chris D.; Hodson, Mark E. [University of Reading, School of Human and Environmental Sciences, Soil Research Centre, Reading, RG6 6DW Berkshire (United Kingdom)

    2011-04-15

    Validating chemical methods to predict bioavailable fractions of polycyclic aromatic hydrocarbons (PAHs) by comparison with accumulation bioassays is problematic. Concentrations accumulated in soil organisms not only depend on the bioavailable fraction but also on contaminant properties. A historically contaminated soil was freshly spiked with deuterated PAHs (dPAHs). dPAHs have a similar fate to their respective undeuterated analogues, so chemical methods that give good indications of bioavailability should extract the fresh more readily available dPAHs and historic more recalcitrant PAHs in similar proportions to those in which they are accumulated in the tissues of test organisms. Cyclodextrin and butanol extractions predicted the bioavailable fraction for earthworms (Eisenia fetida) and plants (Lolium multiflorum) better than the exhaustive extraction. The PAHs accumulated by earthworms had a larger dPAH:PAH ratio than that predicted by chemical methods. The isotope ratio method described here provides an effective way of evaluating other chemical methods to predict bioavailability. - Research highlights: > Isotope ratios can be used to evaluate chemical methods to predict bioavailability. > Chemical methods predicted bioavailability better than exhaustive extractions. > Bioavailability to earthworms was still far from that predicted by chemical methods. - A novel method using isotope ratios to assess the ability of chemical methods to predict PAH bioavailability to soil biota.

  20. Bioavailability of arsenic in soil: pilot study results and design considerations.

    Science.gov (United States)

    Stanek, Edward J; Calabrese, Edward J; Barnes, Ramond M; Danku, John M C; Zhou, Ying; Kostecki, Paul T; Zillioux, Edward

    2010-11-01

    Bioavailability of arsenic (As) from ingested soil is estimated in a two-period experimental study involving 11 subjects/period. In the first period, a 7-day mass-balance study measured As in food/beverages, urine, and stool to estimate bioavailability of As in food and beverages. Food/beverage As bioavailability (percentage ingested that is not in stool samples) is estimated as 91.0% with a 95% confidence interval given by (84.1%, 97.9%). In the second 7-day study period, subjects were placed on an As suppression diet. In the evening of day 2, each subject ingested a capsule containing 0.63 g of soil, including approximately 111.7 µg of soil-As. The bioavailability estimate of As from food and beverage ingestion during the first 2 days of the second period was 89.7%. Bioavailability of soil-As was estimated over the 5-day period following capsule ingestion, accounting for estimated bioavailability of food/beverage As. Assuming analytic recovery rates of As from combined soil and food/beverage samples are equal, soil-As bioavailability is estimated as 48.7% (95% CI [36.2%, 61.3%]). Relative to bioavailability of As from food/beverage sources, soil-As is estimated to be 54.3% (95% CI [40.3%, 68.4%]) as bioavailable.

  1. From conceptual model to remediation: bioavailability, a key to clean up heavy metal contaminated soils.

    Science.gov (United States)

    Petruzzelli, Gianniantonio; Pedron, Francesca; Pezzarossa, Beatrice

    2013-04-01

    Processes of metal bioavailability in the soil To know the bioavailability processes at site specific levels is essential to understand in detail the risks associated with pollution, and to support the decision-making process, i.e. description of the conceptual model and choice of clean up technologies. It is particularly important to assess how chemical, physical and biological processes in the soil affect the reactions leading to adsorption, precipitation or release of contaminants. The measurement of bioavailability One of the main difficulties in the practical application of the bioavailability concept in soil remediation is the lack of consensus on the method to be used to measure bioavailability. The best strategy is to apply a series of tests to assess bioavailability, since no applicable method is universally valid under all conditions. As an example, bioavailability tests for phytotechnology application should consider two distinct aspects: a physico-chemical driven solubilization process and a physiologically driven uptake process. Soil and plant characteristics strongly influence bioavailability. Bioavailability as a tool in remediation strategies Bioavailability can be used at all stages in remediation strategies: development of the conceptual model, evaluation of risk assessment, and selection of the best technology, considering different scenarios and including different environmental objectives. Two different strategies can be followed: the reduction and the increase of bioavailability. Procedures that reduce bioavailability aim to prevent the movement of pollutants from the soil to the living organisms, essentially by: i) removal of the labile phase of the contaminant, i.e. the fraction which is intrinsic to the processes of bioavailability (phytostabilization); ii) conversion of the labile fraction into a stable fraction (precipitation or adsorption); iii) increase of the resistance to mass transfer of the contaminants (inertization). Procedures

  2. Bioavailability of the antiemetic metopimazine given as a microenema

    DEFF Research Database (Denmark)

    Herrstedt, J.; Jørgensen, M.; Angelo, H.R.

    1996-01-01

    The absorption of the antiemetic metopimazine (MPZ) given as a single dose of (a) 40 mg microenema, (b) 40 mg orally and (c) 10 mg as a 60 min i.v. continuous infusion was investigated in six healthy volunteers. Blood samples were drawn and the serum concentrations of MPZ and its acid metabolite ...... were measured. The bioavailability of MPZ given orally and as enemas was 22.3 and 19.5% respectively. Partial avoidance of hepatic first pass metabolism was seen with the enemas, which in contrast to suppositories, seems to represent a reliable form of rectal administration....

  3. Improving Tenoxicam Solubility and Bioavailability by Cosolvent System

    OpenAIRE

    Yeh, Ming-Kung; Chang, Li-Chien; Chiou, Andy Hong-Jey

    2009-01-01

    The formulation study of tenoxicam, a poorly water-soluble drug, was developed by use of a ternary cosolvent system and has significantly enhanced the solubility. Additionally, the relative bioavailability of testing formulation was also evaluated by New Zealand rabbit with a single i.m. injection. The three-phase diagram for dimethylsulfoxide (DMSO)/propylene glycol/water, DMSO/ethanol/water, and DMSO/polyethoxylated castor oil/ethanol system was developed. The volume ratio of 5:4:1 in the D...

  4. Determinants of oral bioavailability of soil-borne contaminants

    OpenAIRE

    Oomen, Agnes Guadalupe

    2001-01-01

    Children ingest soil, either accidentally via hand-to-mouth behavior or deliberately. In this manner, a child ingests on average between 50 and 200 mg soil/day, although amounts of as much as 60 g/day have also been observed. Hence, soil ingestion can be a main route of exposure to soil-borne contaminants to children. To estimate the health risk associated to this exposure route, and to assess intervention values for contaminants in soils, one needs to know the oral bioavailability of the soi...

  5. Content and bioavailability of trace elements in vegetarian diets.

    Science.gov (United States)

    Gibson, R S

    1994-05-01

    This review compares the content and major food sources of copper, manganese, selenium, and zinc in vegetarian and omnivorous diets. Interactions affecting trace element bioavailability and their impact on the trace element status of vegetarians are discussed. Adult vegetarian diets often have a lower zinc and selenium content but a higher copper and manganese content compared with omnivorous diets. Cereals are the primary sources of copper, manganese, and selenium in most diets and the major source of zinc in many vegetarian diets; flesh floods are the primary source of zinc and secondary source of selenium in omnivorous diets. Despite the apparent lower bioavailability of zinc, copper, manganese, and selenium in vegetarian diets because of the high contents of phytic acid and/or dietary fiber and the low content of flesh foods in the diet, the trace element status of most adult vegetarians appears to be adequate. Children, however, appear to be more vulnerable to suboptimal zinc status, presumably because of their high zinc requirements for growth and their bodies' failure to adapt to a vegetarian diet by increased absorption of dietary zinc.

  6. Speciation and bioavailability of zinc in amended sediments

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Aaron G.B.; Scheckel, Kirk G.; McDermott, Gregory; Gratson, David; Neptune, Dean; Ryan, James A.

    2011-12-09

    The speciation and bioavailability of zinc (Zn) in smelter-contaminated sediments were investigated as a function of phosphate (apatite) and organic amendment loading rate. Zinc species identified in preamendment sediment were zinc hydroxide-like phases, sphalerite, and zinc sorbed to an iron oxide via X-ray adsorption near edge structure (XANES) spectroscopy. Four months after adding the amendments to the contaminated sediment, hopeite, a Zn phosphate mineral, was identified indicating phosphate was binding and sequestering available Zn and Zn pore water concentrations were decreased at levels of 90% or more. Laboratory experiments indicate organic amendments exhibit a limited effect and may hinder sequestration of pore water Zn when mixed with apatite. The acute toxicity of the sediment Zn was evaluated with Hyalella azteca, and bioaccumulation of Zn with Lumbriculus variegates. The survivability of H. azteca increased as a function of phosphate (apatite) loading rate. In contaminated sediment without apatite, no specimens of H. azteca survived. The bioaccumulation of Zn in L. variegates also followed a trend of decreased bioaccumulation with increased phosphate loading in the contaminated sediment. The research supports an association between Zn speciation and bioavailability.

  7. Is bioavailability altered in generic versus brand anticonvulsants?

    Science.gov (United States)

    Jankovic, Slobodan M; Ignjatovic Ristic, Dragana

    2015-03-01

    Therapeutic window of anticonvulsants is not a wide one, with phenytoin being one extreme, which can be classified as a narrow therapeutic index drug, since its ratio between the least toxic and the least effective concentration is less than twofold. In order to obtain marketing authorization, a generic anticonvulsant should demonstrate relative bioequivalence with its brand-name counterpart. However, although bioequivalent, generic anticonvulsants still do not have the same bioavailability as brand-name drugs, which may lead to larger fluctuations of steady-state plasma concentrations, and sometimes to loss of seizure control if a patient is switched from brand-name to generic or from generic to generic anticonvulsant. Generic anticonvulsants are effective, safe and affordable drugs for treatment of epilepsy, and patients could be successfully treated with them from the very beginning. It is switching from brand-name to generic anticonvulsant or from one generic anticonvulsant to another that should be avoided in clinical practice, since subtle differences in bioavailability may disturb optimal degree of seizure control to which the patient was previously successfully titrated.

  8. Polyphenols: Extraction Methods, Antioxidative Action, Bioavailability and Anticarcinogenic Effects

    Directory of Open Access Journals (Sweden)

    Eva Brglez Mojzer

    2016-07-01

    Full Text Available Being secondary plant metabolites, polyphenols represent a large and diverse group of substances abundantly present in a majority of fruits, herbs and vegetables. The current contribution is focused on their bioavailability, antioxidative and anticarcinogenic properties. An overview of extraction methods is also given, with supercritical fluid extraction highlighted as a promising eco-friendly alternative providing exceptional separation and protection from degradation of unstable polyphenols. The protective role of polyphenols against reactive oxygen and nitrogen species, UV light, plant pathogens, parasites and predators results in several beneficial biological activities giving rise to prophylaxis or possibly even to a cure for several prevailing human diseases, especially various cancer types. Omnipresence, specificity of the response and the absence of or low toxicity are crucial advantages of polyphenols as anticancer agents. The main problem represents their low bioavailability and rapid metabolism. One of the promising solutions lies in nanoformulation of polyphenols that prevents their degradation and thus enables significantly higher concentrations to reach the target cells. Another, more practiced, solution is the use of mixtures of various polyphenols that bring synergistic effects, resulting in lowering of the required therapeutic dose and in multitargeted action. The combination of polyphenols with existing drugs and therapies also shows promising results and significantly reduces their toxicity.

  9. Stabilizing Agents for Drug Nanocrystals: Effect on Bioavailability

    Directory of Open Access Journals (Sweden)

    Annika Tuomela

    2016-05-01

    Full Text Available Drug nanocrystals are a versatile option for drug delivery purposes, and while the number of poorly soluble drug materials is all the time increasing, more research in this area is performed. Drug nanocrystals have a simple structure—a solid drug core is surrounded by a layer of stabilizing agent. However, despite the considerably simple structure, the selection of an appropriate stabilizer for a certain drug can be challenging. Mostly, the stabilizer selection is based purely on the requirement of physical stability, e.g., maintaining the nanosized particle size as long as possible after the formation of drug nanocrystals. However, it is also worth taking into account that stabilizer can affect the bioavailability in the final formulation via interactions with cells and cell layers. In addition, formation of nanocrystals is only one process step, and for the final formulation, more excipients are often added to the composition. The role of the stabilizers in the final formulation can be more than only stabilizing the nanocrystal particle size. A good example is the stabilizer’s role as cryoprotectant during freeze drying. In this review, the stabilizing effect, role of stabilizers in final nanocrystalline formulations, challenges in reaching in vitro–in vivo correlation with nanocrystalline products, and stabilizers’ effect on higher bioavailability are discussed.

  10. Vanadium bioavailability in soils amended with blast furnace slag.

    Science.gov (United States)

    Larsson, Maja A; Baken, Stijn; Smolders, Erik; Cubadda, Francesco; Gustafsson, Jon Petter

    2015-10-15

    Blast furnace (BF) slags are commonly applied as soil amendments and in road fill material. In Sweden they are also naturally high in vanadium. The aim of this study was to assess the vanadium bioavailability in BF slags when applied to soil. Two soils were amended with up to 29% BF slag (containing 800 mg V kg(-1)) and equilibrated outdoors for 10 months before conducting a barley shoot growth assay. Additional soil samples were spiked with dissolved vanadate(V) for which assays were conducted two weeks (freshly spiked) and 10 months (aged) after spiking. The BF slag vanadium was dominated by vanadium(III) as shown by V K-edge XANES spectroscopy. In contrast, results obtained by HPLC-ICP-MS showed that vanadium(V), the most toxic vanadium species, was predominant in the soil solution. Barley shoot growth was not affected by the BF slag additions. This was likely due to limited dissolution of vanadium from the BF slag, preventing an increase of dissolved vanadium above toxic thresholds. The difference in vanadium bioavailability among treatments was explained by the vanadium concentration in the soil solution. It was concluded that the vanadium in BF slag is sparingly available. These findings should be of importance in environmental risk assessment.

  11. Bioavailable copper modulates oxidative phosphorylation and growth of tumors.

    Science.gov (United States)

    Ishida, Seiko; Andreux, Pénélope; Poitry-Yamate, Carole; Auwerx, Johan; Hanahan, Douglas

    2013-11-26

    Copper is an essential trace element, the imbalances of which are associated with various pathological conditions, including cancer, albeit via largely undefined molecular and cellular mechanisms. Here we provide evidence that levels of bioavailable copper modulate tumor growth. Chronic exposure to elevated levels of copper in drinking water, corresponding to the maximum allowed in public water supplies, stimulated proliferation of cancer cells and de novo pancreatic tumor growth in mice. Conversely, reducing systemic copper levels with a chelating drug, clinically used to treat copper disorders, impaired both. Under such copper limitation, tumors displayed decreased activity of the copper-binding mitochondrial enzyme cytochrome c oxidase and reduced ATP levels, despite enhanced glycolysis, which was not accompanied by increased invasiveness of tumors. The antiproliferative effect of copper chelation was enhanced when combined with inhibitors of glycolysis. Interestingly, larger tumors contained less copper than smaller tumors and exhibited comparatively lower activity of cytochrome c oxidase and increased glucose uptake. These results establish copper as a tumor promoter and reveal that varying levels of copper serves to regulate oxidative phosphorylation in rapidly proliferating cancer cells inside solid tumors. Thus, activation of glycolysis in tumors may in part reflect insufficient copper bioavailability in the tumor microenvironment.

  12. Functionalized Polymers for Enhance Oral Bioavailability of Sensitive Molecules

    Directory of Open Access Journals (Sweden)

    Yolanda Alvarado Pérez

    2016-06-01

    Full Text Available Currently, many sensitive molecules have been studied for effective oral administration. These substances are biologically active compounds that mainly suffer early degradation in the gastrointestinal tract (GIT and physicochemical instability, inactivation and poor solubility and permeability. The sensibility of the biomolecules has limited their oral administration in the body and today is an important research topic to achieve desired effects in medicine field. Under this perspective, various enhancement approaches have been studied as alternatives to increase their oral bioavailability. Some of these strategies include functionalized polymers to provide specific useful benefits as protection to the intestinal tract by preventing its degradation by stomach enzymes, to increase their absorption, permeability, stability, and to make a proper release in the GIT. Due to specific chemical groups, shapes and sizes, morphologies, mechanical properties, and degradation, recent advances in functionalized polymers have opened the door to great possibilities to improve the physicochemical characteristics of these biopharmaceuticals. Today, many biomolecules are found in basic studies, preclinical steps, and others are late stage clinical development. This review summarizes the contribution of functionalized polymers to enhance oral bioavailability of sensitive molecules and their application status in medicine for different diseases. Future trends of these polymers and their possible uses to achieve different formulation goals for oral delivery are also covered in this manuscript.

  13. Bioavailability, metabolism and potential health protective effects of dietary flavonoids

    DEFF Research Database (Denmark)

    Bredsdorff, Lea

    Dietary flavonoids constitute an important group of potential health protective compounds from fruits, vegetables, and plant-based products such as tea and wine. The beneficial effects of a diet high in flavonoids on the risk of coronary heart disease (CHD) have been shown in several epidemiologi......Dietary flavonoids constitute an important group of potential health protective compounds from fruits, vegetables, and plant-based products such as tea and wine. The beneficial effects of a diet high in flavonoids on the risk of coronary heart disease (CHD) have been shown in several....... The present thesis was initiated with two objectives. One objective was to investigate the bioavailability and metabolism of the dietary important flavonoids hesperetin and naringenin from commercial, hesperidin-fortified, and enzymatically treated orange juice. The other objective was to explore...... the association between exposure to dietary flavonoids and the risk of acute coronary syndrome (ACS) in a nested case-control study. The bioavailability and metabolism of hesperetin and naringenin was investigated by analysing urine and plasma from 16 subjects after consumption of three treatments of orange juice...

  14. Pharmaceutical and pharmacological approaches for bioavailability enhancement of etoposide

    Indian Academy of Sciences (India)

    Ishtiyaq Ahmad Najar; Rakesh Kamal Johri

    2014-03-01

    Etoposide, a semi-synthetic derivative of podophyllotoxin, is one of the most active and useful antineoplastic agent used routinely in firstline combination chemotherapy of testicular cancer, small-cell lung cancer and non-Hodgkin’s lymphoma. Etoposide displays narrow therapeutic index, erratic pharmacokinetics and dose individualization that needs to be achieved for overcoming inter- and intra-patient variability (25–80%), so as to maintain proper drug exposure within a therapeutic range. Etoposide posses high plasma protein binding (97%) and is degraded via complex metabolic pathways. The main pharmacokinetic determinants of etoposide are still not completely defined in order to optimize the pharmaco-therapeutic parameters including dose, therapeutic schedule and route of administration. Much research has been done to determine drug–drug and herb–drug interactions for improving the bioavailability of etoposide. The present article gives insight on pharmaceutical and pharmacological attempts made from time to time to overcome the erratic inter- and intra-patient variability for improving the bioavailability of etoposide.

  15. Influence of estuarine processes on spatiotemporal variation in bioavailable selenium

    Science.gov (United States)

    Stewart, Robin; Luoma, Samuel N.; Elrick, Kent A.; Carter, James L.; van der Wegen, Mick

    2013-01-01

    Dynamic processes (physical, chemical and biological) challenge our ability to quantify and manage the ecological risk of chemical contaminants in estuarine environments. Selenium (Se) bioavailability (defined by bioaccumulation), stable isotopes and molar carbon-tonitrogen ratios in the benthic clam Potamocorbula amurensis, an important food source for predators, were determined monthly for 17 yr in northern San Francisco Bay. Se concentrations in the clams ranged from a low of 2 to a high of 22 μg g-1 over space and time. Little of that variability was stochastic, however. Statistical analyses and preliminary hydrodynamic modeling showed that a constant mid-estuarine input of Se, which was dispersed up- and down-estuary by tidal currents, explained the general spatial patterns in accumulated Se among stations. Regression of Se bioavailability against river inflows suggested that processes driven by inflows were the primary driver of seasonal variability. River inflow also appeared to explain interannual variability but within the range of Se enrichment established at each station by source inputs. Evaluation of risks from Se contamination in estuaries requires the consideration of spatial and temporal variability on multiple scales and of the processes that drive that variability.

  16. Vanadium bioavailability in soils amended with blast furnace slag

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, Maja A., E-mail: maja.larsson@slu.se [Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, 750 07 Uppsala (Sweden); Baken, Stijn, E-mail: stijn.baken@ees.kuleuven.be [Department of Earth and Environmental Sciences, Leuven University, Kasteelpark Arenberg 20 bus 2459, 3001 Leuven (Belgium); Smolders, Erik, E-mail: erik.smolders@ees.kuleuven.be [Department of Earth and Environmental Sciences, Leuven University, Kasteelpark Arenberg 20 bus 2459, 3001 Leuven (Belgium); Cubadda, Francesco, E-mail: francesco.cubadda@iss.it [Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161 (Italy); Gustafsson, Jon Petter, E-mail: jon-petter.gustafsson@slu.se [Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, 750 07 Uppsala (Sweden); Division of Land and Water Resources Engineering, KTH Royal Institute of Technology, Brinellvägen 28, 100 44 Stockholm (Sweden)

    2015-10-15

    Blast furnace (BF) slags are commonly applied as soil amendments and in road fill material. In Sweden they are also naturally high in vanadium. The aim of this study was to assess the vanadium bioavailability in BF slags when applied to soil. Two soils were amended with up to 29% BF slag (containing 800 mg V kg{sup −1}) and equilibrated outdoors for 10 months before conducting a barley shoot growth assay. Additional soil samples were spiked with dissolved vanadate(V) for which assays were conducted two weeks (freshly spiked) and 10 months (aged) after spiking. The BF slag vanadium was dominated by vanadium(III) as shown by V K-edge XANES spectroscopy. In contrast, results obtained by HPLC-ICP-MS showed that vanadium(V), the most toxic vanadium species, was predominant in the soil solution. Barley shoot growth was not affected by the BF slag additions. This was likely due to limited dissolution of vanadium from the BF slag, preventing an increase of dissolved vanadium above toxic thresholds. The difference in vanadium bioavailability among treatments was explained by the vanadium concentration in the soil solution. It was concluded that the vanadium in BF slag is sparingly available. These findings should be of importance in environmental risk assessment.

  17. Bioavailability of seocalcitol I: Relating solubility in biorelevant media with oral bioavailability in rats--effect of medium and long chain triglycerides

    DEFF Research Database (Denmark)

    Grove, Mette; Pedersen, Gitte P; Nielsen, Jeanet L

    2005-01-01

    the influence of fatty acid chain length on the in vitro solubility of seocalcitol. The same solubility of seocalcitol was found in media containing either MC-LP or LC-LP. The bioavailability after oral administration of seocalcitol dissolved in medium chain triglyceride (MCT), long chain triglyceride (LCT......), and a reference formulation containing propylene glycol (PG) was studied in vivo in rats. The lipid formulations showed a twofold increase in bioavailability compared with the reference formulation, indicating positive effects of lipids on the bioavailability reflecting a better solubility in the intestine...... and protection against precipitation of seocalcitol in the gastro intestinal tract. There was no difference in the in vivo bioavailability of seocalcitol between the MCT and the LCT solutions, which correlates with the identical in vitro solubility of seocalcitol in SIM containing MC-LP or LC-LP....

  18. Remediation of a Mercury-Contaminated Industrial Soil Using Bioavailable Contaminant Stripping

    Institute of Scientific and Technical Information of China (English)

    F.PEDRON; G.PETRUZZELLI; M.BARBAFIERI; E.TASSI

    2013-01-01

    The method to remove bioavailable amounts of heavy metals from a contaminated soil by using plants is defined as bioavailable contaminant stripping (BCS) and could safely be applied if the soil's long-term ability to replenish the bioavailable pool is known.The aim of this study was to evaluate the ability of three common plant species selected,Brassica juncea,Poa annua,and Helianthus annus,to remove bioavailable amounts of mercury (Hg) from a contaminated industrial soil containing 15.1 mg kg-1 Hg.Trials were carried out under greenhouse conditions using pots (mesocosms).According to the precautionary principle,we modified the BCS remediation approach by adding a new step,in which mercury bioavailability was increased by the addition of a strong mobilizing agent,ammonium thiosulphate,(NH4)2S2O3,to obtain an estimate of the likely long-term bioavailable Hg pool.The modified BCS remediation approach was called enhanced bioavailable contaminant stripping (EBCS).After one growth cycle,nearly all the bioavailable mercury (95.7%) was removed and the metal remaining in the soil was considered inert since it was neither extractable by (NH4)2S2O3 nor taken up by plants during a second growth cycle.The results demonstrated that EBCS appeared promising since it removed the most dangerous metal forms while substantially shortening the cleanup time.

  19. Possibilities of implementation of bioavailability methods for organic contaminants in the Dutch Soil Quality Assessment Framework.

    Science.gov (United States)

    Brand, Ellen; Lijzen, Johannes; Peijnenburg, Willie; Swartjes, Frank

    2013-10-15

    In the Netherlands, risk assessment of contaminated soils is based on determining the total contaminant concentration. If this measured soil concentration exceeds the Soil Quality Standards (SQS) a higher tier risk evaluation must be performed. Experiences from the field have given rise to the perception that performing risk evaluations based on (measured) total concentrations may lead to an inaccurate assessment of the actual risks. Assuming that only the bioavailable fraction is capable of exerting adverse effects in the soil ecosystem, it is suggested, that by taking bioavailability into account in a (higher tier) risk evaluation, a more effect-based risk assessment can be performed. Bioavailability has been a subject of research for several decades. However up to now bioavailability has not been implemented in the Dutch Soil Quality Assessment Framework. First actions were taken in the Netherlands to determine whether the concept of bioavailability could be implemented in the risk assessment of contaminated soils and to find out how bioavailability can become part of the Dutch Soil Quality Assessment Framework. These actions have led to a concrete proposal for implementation of bioavailability methods in the risk assessment of organic contaminants in soils. This paper focuses on the chemical prediction of bioavailability for ecological risk assessment of contaminated soils.

  20. Bioavailability of iron, zinc, folic acid, and vitamin A from fortified maize.

    Science.gov (United States)

    Moretti, Diego; Biebinger, Ralf; Bruins, Maaike J; Hoeft, Birgit; Kraemer, Klaus

    2014-04-01

    Several strategies appear suitable to improve iron and zinc bioavailability from fortified maize, and fortification per se will increase the intake of bioavailable iron and zinc. Corn masa flour or whole maize should be fortified with sodium iron ethylenediaminetetraacetate (NaFeEDTA), ferrous fumarate, or ferrous sulfate, and degermed corn flour should be fortified with ferrous sulfate or ferrous fumarate. The choice of zinc fortificant appears to have a limited impact on zinc bioavailability. Phytic acid is a major inhibitor of both iron and zinc absorption. Degermination at the mill will reduce phytic acid content, and degermed maize appears to be a suitable vehicle for iron and zinc fortification. Enzymatic phytate degradation may be a suitable home-based technique to enhance the bioavailability of iron and zinc from fortified maize. Bioavailability experiments with low phytic acid-containing maize varieties have suggested an improved zinc bioavailability compared to wild-type counterparts. The bioavailability of folic acid from maize porridge was reported to be slightly higher than from baked wheat bread. The bioavailability of vitamin A provided as encapsulated retinyl esters is generally high and is typically not strongly influenced by the food matrix, but has not been fully investigated in maize.

  1. 21 CFR 320.25 - Guidelines for the conduct of an in vivo bioavailability study.

    Science.gov (United States)

    2010-04-01

    ... bioavailability study is that no unnecessary human research should be done. (2) An in vivo bioavailability study... of analytical methods. (4) Benefit-risk considerations in regard to testing in humans. (c) Comparison... not been approved for marketing can be used to measure the following pharmacokinetic data: (i)...

  2. Geochemical partitioning of Cu and Ni in mangrove sediments: Relationships with their bioavailability

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Ramteke, D.; Chakraborty, S.

    ) was determined and used as an indicator of bioavailability of metal. An attempt was made to establish a mechanistic linkage between the non-residual metal complexes and their bioavailability in the mangrove system. The non-residual fractions of Cu and Ni were...

  3. 21 CFR 320.21 - Requirements for submission of bioavailability and bioequivalence data.

    Science.gov (United States)

    2010-04-01

    ... bioequivalence data. 320.21 Section 320.21 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE BIOAVAILABILITY AND BIOEQUIVALENCE REQUIREMENTS Procedures for Determining the Bioavailability or Bioequivalence of Drug Products § 320.21 Requirements...

  4. 21 CFR 320.24 - Types of evidence to measure bioavailability or establish bioequivalence.

    Science.gov (United States)

    2010-04-01

    ... establish bioequivalence. 320.24 Section 320.24 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE BIOAVAILABILITY AND BIOEQUIVALENCE REQUIREMENTS Procedures for Determining the Bioavailability or Bioequivalence of Drug Products § 320.24 Types of...

  5. 21 CFR 320.29 - Analytical methods for an in vivo bioavailability or bioequivalence study.

    Science.gov (United States)

    2010-04-01

    ... or bioequivalence study. 320.29 Section 320.29 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE BIOAVAILABILITY AND BIOEQUIVALENCE REQUIREMENTS Procedures for Determining the Bioavailability or Bioequivalence of Drug Products §...

  6. 21 CFR 320.23 - Basis for measuring in vivo bioavailability or demonstrating bioequivalence.

    Science.gov (United States)

    2010-04-01

    ... demonstrating bioequivalence. 320.23 Section 320.23 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE BIOAVAILABILITY AND BIOEQUIVALENCE REQUIREMENTS Procedures for Determining the Bioavailability or Bioequivalence of Drug Products § 320.23 Basis...

  7. Advances In Assessing Bioavailability Of Metal(Loid)s In Contaminated Soils

    Science.gov (United States)

    The term bioavailability has many different meanings across various disciplines of toxicology and pharmacology. Often bioavailability is concerned with human health aspects such as in the case of lead (Pb) ingestion by children. However, some of the most contaminated sites are ...

  8. Bioavailability of Food Folates is 80% of that of folic acid 1-3

    NARCIS (Netherlands)

    Winkels, R.M.; Brouwer, I.A.; Siebelink, E.; Katan, M.B.; Verhoef, P.

    2007-01-01

    Background: The bioavailability of natural food folates is lower than that of synthetic folic acid, but no agreement exists as to the extent of the difference. Objective: In a 4-wk dietary intervention study, we determined the aggregate bioavailability of food folates from fruit, vegetables, and liv

  9. Iron bioavailability of maize hemoglobin in a Caco-2 cell culture model.

    Science.gov (United States)

    Bodnar, Anastasia L; Proulx, Amy K; Scott, M Paul; Beavers, Alyssa; Reddy, Manju B

    2013-07-31

    Maize ( Zea mays ) is an important staple crop in many parts of the world but has low iron bioavailability, in part due to its high phytate content. Hemoglobin is a form of iron that is highly bioavailable, and its bioavailability is not inhibited by phytate. It was hypothesized that maize hemoglobin is a highly bioavailable iron source and that biofortification of maize with iron can be accomplished by overexpression of maize globin in the endosperm. Maize was transformed with a gene construct encoding a translational fusion of maize globin and green fluorescent protein under transcriptional control of the maize 27 kDa γ-zein promoter. Iron bioavailability of maize hemoglobin produced in Escherichia coli and of stably transformed seeds expressing the maize globin-GFP fusion was determined using an in vitro Caco-2 cell culture model. Maize flour fortified with maize hemoglobin was found to have iron bioavailability that is not significantly different from that of flour fortified with ferrous sulfate or bovine hemoglobin but is significantly higher than unfortified flour. Transformed maize grain expressing maize globin was found to have iron bioavailability similar to that of untransformed seeds. These results suggest that maize globin produced in E. coli may be an effective iron fortificant, but overexpressing maize globin in maize endosperm may require a different strategy to increase bioavailable iron content in maize.

  10. Synthetic and tomato-based lycopene have identical bioavailability in humans

    NARCIS (Netherlands)

    Hoppe, P.P.; Krämer, K.; Berg, H. van den; Steenge, G.; Vliet, T. van

    2003-01-01

    Background: Bioavailability studies with lycopene have focused on natural sources. A synthetic source has recently become available. Aim of the study: To determine the relative bioavailabilities of synthetic and tomato-based lycopene in free living volunteers in a single-blind, randomized, placebo-c

  11. Bioavailability and antioxidant effects of olive oil phenols in humans: a review

    NARCIS (Netherlands)

    Vissers, M.N.; Katan, M.B.; Zock, P.L.

    2004-01-01

    Objective: We reviewed the bioavailability and antioxidant effects of phenols from extra virgin olive oil. Search strategy: We searched the MEDLINE database for the years 1966 - 2002. To review the bioavailability of olive oil phenols, we selected animal and human studies that studied the absorption

  12. Bioavailability and Bioaccumulation of Metal-Based Engineered Nanomaterials in Aquatic Environments

    DEFF Research Database (Denmark)

    Luoma, Samuel; Khan, Farhan R.; Croteau, Marie-Noelle

    2014-01-01

    Bioavailability of Me-ENMs to aquatic organisms links their release into the environment to ecological implications. Close examination shows some important differences in the conceptual models that define bioavailability for metals and Me-ENMs. Metals are delivered to aquatic animals from Me-ENMs...

  13. Oral bioavailability of moxifloxacin after Roux-en-Y gastric bypass surgery

    NARCIS (Netherlands)

    De Smet, Julie; Colin, Pieter; De Paepe, Peter; Ruige, Johannes; Batens, Helene; Van Nieuwenhove, Yves; Vogelaers, Dirk; Blot, Stijn; Van Bocxlaer, Jan; Van Bortel, Luc M.; Boussery, Koen

    2012-01-01

    Objectives: Roux-en-Y gastric bypass surgery is the most commonly performed procedure for the treatment of morbid obesity. This anatomical alteration may affect the absorption and consequently the bioavailability of oral drugs. This study aims to investigate the oral bioavailability of moxifloxacin

  14. Biosurfactants and increased bioavailability of sorbed organic contaminants: Measurements using a biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Strong-Gunderson, J.M.; Palumbo, A.V. [Oak Ridge National Lab., TN (United States); Applegate, B.; Saylor, G.S. [Tennessee Univ., Knoxville, TN (United States)

    1993-12-31

    Bioremediation of sites contaminated with hydrophobic materials that sorb onto the soil matrix is very difficult due to reduced microbial (bio)availability. Following biosurfactant addition, we have measured an increase in contaminant bioavailability by using a lux biosensor. Direct microbial bioavailability was determined by using a genetically engineered microbial bioreporter strain of Pseudomonas putida. This strain was engineered so the lux genes, which code for light production, are transcriptionally fused with genes that code for contaminant degradation and are thus induced in the presence of specific compounds. By using a bioreporter we can quantify the actual microbial bioavailability of the contaminants and compare it to concentrations measured by other analytical methods (e.g. gas chromatograph). It is possible that these values are not equal to each other. Thus, bioremediation rates may not be accurately predicted if bioavailability is not considered.

  15. In vitro bioavailability of iron from the heme analogue sodium iron chlorophyllin.

    Science.gov (United States)

    Miret, Silvia; Tascioglu, Serpil; van der Burg, Monique; Frenken, Leon; Klaffke, Werner

    2010-01-27

    The use of heme analogues from vegetable origin could provide an alternative iron source of potentially high bioavailability. Sodium iron chlorophyllin is a water-soluble semisynthetic chlorophyll derivative where the magnesium in the porphyrin ring has been substituted by iron. We have used an in vitro model that combines gastric and intestinal digestion followed by intestinal iron uptake in Caco-2 cells to determine the bioavailability of iron from sodium iron chlorophyllin. Our results demonstrate that sodium iron chlorophyllin is stable under simulated gastrointestinal conditions and is able to deliver bioavailable iron to Caco-2 cells. Similar to the heme, the bioavailability of iron from sodium iron chlorophyllin is dependent on the food matrix, and it was inhibited by calcium. Potentially, sodium iron chlorophyllin could be used as an iron fortificant from vegetable origin with high bioavailability.

  16. Bioavailability of cadmium from infant diets in newborn rats

    Energy Technology Data Exchange (ETDEWEB)

    Eklund, G.; Oskarsson, A. [Dept. of Pharmacology and Toxicology, Swedish University of Agricultural Sciences, Uppsala (Sweden); Petersson Grawe, K. [Toxicology Div., National Food Administration, Uppsala (Sweden)

    2001-11-01

    Infants are exposed to higher levels of cadmium (Cd) from infant and follow-on formulas than from breast milk. We studied the bioavailability of {sup 109}CdCl{sub 2} from cows' milk formula, soy formula, wheat/oat/milk formula, wholemeal/milk formula and water in 11-day-old rat pups. The pups received a single oral dose of one diet labelled with {sup 109}Cd, 0.1 or 0.3 mg Cd/kg body weight. After 2 or 24 h or 4, 9 or 12 days the fractional retention of {sup 109}Cd in the whole body, in segments of rinsed small intestine and in tissue was measured in a gamma counter. Pups receiving {sup 109}Cd in water or cows' milk formula had the highest mean whole-body retention. It ranged from 67% of the dose in the water group to 52% in the wholemeal/milk formula group 4 days after dosing. The retention of {sup 109}Cd in the rinsed small intestine was significantly higher in the water group and the cows' milk formula group than in the cereal-based formula groups at 24 h and 4 days after dosing. It was still high in all groups on day 9, ranging from 26 to 11%. Initially most of the {sup 109}Cd was retained in the duodenum but by day 4 it had moved further down into the jejunum. In the liver, the highest and lowest retention on day 4 was 16 permille and 3 permille of the dose in the water group and wholemeal/milk formula group, respectively. In the kidney, {sup 109}Cd was still increasing 12 days after exposure in all groups. Whole-body retention and tissue levels were higher than previously reported in adult animals. The lower bioavailability of {sup 109}Cd from the cereal-based formulas compared to water and cows' milk formula on the longer survival times is most likely explained by Cd binding to dietary fibre and phytic acid in the cereal-based formulas reducing the intestinal binding and decreasing the bioavailability of Cd. The high retention of {sup 109}Cd in the small intestine, leading to a prolonged absorption period, emphasizes the importance of

  17. Pharmacokinetics and bioavailability of R-phencynonate in Beagle dogs

    Institute of Scientific and Technical Information of China (English)

    LI Jing-lai; CUI Meng-cun; WANG Xiao-ying; QIAO Jian-zhong; ZHANG Zhen-qing; RUAN Jin-xiu; ZhONG Bo-hua; LIU Ke-liang

    2008-01-01

    Objective To evaluate the pharmacokinetics (PK) properties and bioavailability of R-pbencynonate (L-8021) in Beagle dogs. Methods Fifteen healthy Beagle dogs were randomly divided into three groups, each group was orally given single dose of 0.1 mg·kg-1, 0.4 mg·kg-1 and 1.2 mg·kg-1 R-pbencynonate respectively. After one week cleaning, the middle dose group was injected 0.4 mg·kg-1 dose. Blood samples (about 2 mL) were collected in heparinized tubes before dosing and at 0. 033, 0. 083, 0.25, 0.5, 0.75, 1,2, 4, 6, 8, 12 h after administration, and were then immediately centrifuged at 2000 g for 15 min. The pharmacokineties (PK) properties and bioavailability of the drugs was evaluated using the liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method. Results After p. o. administration of 0.1, 0.4 and 1.2 mg·kg-1 R-phencynonate, tmax ranged within 0.65-1.2 h;t1/2 ranged within 2.84-3.36 h; CLz/F ranged within 5.00-9.32 L·h-1·kg-1; Cmax ranged within 1.87-70.34 ng·mL-1; AUC(0.t) ranged within 9.80-250.12 μg·L-1. h; After i. v. administration of 0.4 mg·kg-1, t1/2 was 2.52 h; AUG(0-t) was 238.11 μg·L-1·h. Conclnsions L-8021 was dose-dependent within the range of 0.1-1.2 mg·kg-1 in Beagle dogs and the blood drug concentration-time curves were all best fitted to first order absorption two-compartment open model after via po administration of three different dosages. Following oral administration to Beagle dogs, the absolute bioavailability of L-8021 was 17.82 %, which was very low and resulted from poor absorption.

  18. Bioavailability of phosphorus in meat and bone meal for swine.

    Science.gov (United States)

    Traylor, S L; Cromwell, G L; Lindemann, M D

    2005-05-01

    Meat and bone meal (MBM), when supplemented with tryptophan, is an excellent protein source for pigs. It is also a rich source of Ca and P, but some research has suggested that the bioavailability of P is variable. Experiment 1 further examined the bioavailability of P in MBM. The MBM was obtained directly from a plant and was processed to pass through a 10-mesh screen. It contained 50.7% CP, 2.26% lysine, 10.0% Ca, and 5.0% P (air-dry basis). Individually penned pigs (n = 35; 17 kg initial BW) were fed (ad libitum basis) a low-P, corn-soybean meal-basal diet (0.95% lysine, 0.70% Ca, 0.34% P; as-fed basis) or the basal with graded levels of added P (0.067, 0.133, 0.200%) from monosodium phosphate (MSP) or MBM for 40 d. The Ca level was 0.70% in all diets. Diets were fortified with salt, vitamins, and trace minerals. At termination, the third and fourth metacarpals and metatarsals and femurs were removed from all pigs. Growth rate and feed:gain improved linearly (P Bone strength and ash increased linearly (P meal or corn-soybean meal-MBM diets from 45 to 110 kg BW to evaluate MBM as the sole source of supplemental P. The MBM (54% CP, 2.3% lysine, 9.2% Ca, 4.4% P; air-dry basis) was substituted for corn and soybean meal on a lysine basis, and crystalline lysine was added to all diets at 0.15%. Tryptophan was included in diets containing MBM. Treatments were arranged in a 2 x 2 factorial with P source (dicalcium phosphate or MBM) and P level as the two factors. The two levels of P and Ca were at the NRC requirement or the NRC level plus 0.10% additional P and Ca. Performance, carcass traits, and bone strength were not affected by source of P and Ca, but bone strength was greater (P < 0.01) at the higher P and Ca level. These results indicate that the bioavailability of P in MBM, relative to that in MSP, is high (approximately 91%) for growing pigs, and MBM can serve as the sole source of supplemental P and Ca for finishing pigs.

  19. Bioavailability and ecotoxicity of arsenic species in solution culture and soil system: implications to remediation.

    Science.gov (United States)

    Bolan, Nanthi; Mahimairaja, Santiago; Kunhikrishnan, Anitha; Seshadri, Balaji; Thangarajan, Ramya

    2015-06-01

    In this work, bioavailability and ecotoxicity of arsenite (As(III)) and arsenate (As(V)) species were compared between solution culture and soil system. Firstly, the adsorption of As(III) and As(V) was compared using a number of non-allophanic and allophanic soils. Secondly, the bioavailability and ecotoxicity were examined using germination, phytoavailability, earthworm, and soil microbial activity tests. Both As-spiked soils and As-contaminated sheep dip soils were used to test bioavailability and ecotoxicity. The sheep dip soil which contained predominantly As(V) species was subject to flooding to reduce As(V) to As(III) and then used along with the control treatment soil to compare the bioavailability between As species. Adsorption of As(V) was much higher than that of As(III), and the difference in adsorption between these two species was more pronounced in the allophanic than non-allophanic soils. In the solution culture, there was no significant difference in bioavailability and ecotoxicity, as measured by germination and phytoavailability tests, between these two As species. Whereas in the As-spiked soils, the bioavailability and ecotoxicity were higher for As(III) than As(V), and the difference was more pronounced in the allophanic than non-allophanic soils. Bioavailability of As increased with the flooding of the sheep dip soils which may be attributed to the reduction of As(V) to As(III) species. The results in this study have demonstrated that while in solution, the bioavailability and ecotoxicity do not vary between As(III) and As(V), in soils, the latter species is less bioavailable than the former species because As(V) is more strongly retained than As(III). Since the bioavailability and ecotoxicity of As depend on the nature of As species present in the environment, risk-based remediation approach should aim at controlling the dynamics of As transformation.

  20. Iron Bioavailability and Provitamin A from Sweet Potato- and Cereal-Based Complementary Foods

    Science.gov (United States)

    Christides, Tatiana; Amagloh, Francis Kweku; Coad, Jane

    2015-01-01

    Iron and vitamin A deficiencies in childhood are public health problems in the developing world. Introduction of cereal-based complementary foods, that are often poor sources of both vitamin A and bioavailable iron, increases the risk of deficiency in young children. Alternative foods with higher levels of vitamin A and bioavailable iron could help alleviate these micronutrient deficiencies. The objective of this study was to compare iron bioavailability of β-carotene-rich sweet potato-based complementary foods (orange-flesh based sweet potato (OFSP) ComFa and cream-flesh sweet potato based (CFSP) ComFa with a household cereal-based complementary food (Weanimix) and a commercial cereal (Cerelac®), using the in vitro digestion/Caco-2 cell model. Iron bioavailability relative to total iron, concentrations of iron-uptake inhibitors (fibre, phytates, and polyphenols), and enhancers (ascorbic acid, ß-carotene and fructose) was also evaluated. All foods contained similar amounts of iron, but bioavailability varied: Cerelac® had the highest, followed by OFSP ComFa and Weanimix, which had equivalent bioavailable iron; CFSP ComFa had the lowest bioavailability. The high iron bioavailability from Cerelac® was associated with the highest levels of ascorbic acid, and the lowest levels of inhibitors; polyphenols appeared to limit sweet potato-based food iron bioavailability. Taken together, the results do not support that CFSP- and OFSP ComFa are better sources of bioavailable iron compared with non-commercial/household cereal-based weaning foods; however, they may be a good source of provitamin A in the form of β-carotene.

  1. Iron Bioavailability and Provitamin A from Sweet Potato- and Cereal-Based Complementary Foods

    Directory of Open Access Journals (Sweden)

    Tatiana Christides

    2015-09-01

    Full Text Available Iron and vitamin A deficiencies in childhood are public health problems in the developing world. Introduction of cereal-based complementary foods, that are often poor sources of both vitamin A and bioavailable iron, increases the risk of deficiency in young children. Alternative foods with higher levels of vitamin A and bioavailable iron could help alleviate these micronutrient deficiencies. The objective of this study was to compare iron bioavailability of β-carotene-rich sweet potato-based complementary foods (orange-flesh based sweet potato (OFSP ComFa and cream-flesh sweet potato based (CFSP ComFa with a household cereal-based complementary food (Weanimix and a commercial cereal (Cerelac®, using the in vitro digestion/Caco-2 cell model. Iron bioavailability relative to total iron, concentrations of iron-uptake inhibitors (fibre, phytates, and polyphenols, and enhancers (ascorbic acid, ß-carotene and fructose was also evaluated. All foods contained similar amounts of iron, but bioavailability varied: Cerelac® had the highest, followed by OFSP ComFa and Weanimix, which had equivalent bioavailable iron; CFSP ComFa had the lowest bioavailability. The high iron bioavailability from Cerelac® was associated with the highest levels of ascorbic acid, and the lowest levels of inhibitors; polyphenols appeared to limit sweet potato-based food iron bioavailability. Taken together, the results do not support that CFSP- and OFSP ComFa are better sources of bioavailable iron compared with non-commercial/household cereal-based weaning foods; however, they may be a good source of provitamin A in the form of β-carotene.

  2. Environmental risk assessment of metals: tools for incorporating bioavailability.

    Science.gov (United States)

    Janssen, C R; Heijerick, D G; De Schamphelaere, K A C; Allen, H E

    2003-03-01

    In this paper, some of the main processes and parameters which affect metal bioavailability and toxicity in the aquatic environment and its implications for metal risk assessment procedures will be discussed. It has become clear that, besides chemical processes (speciation, complexation), attention should also be given to physiological aspects for predicting metal toxicity. The development of biotic ligand models (BLMs), which combine speciation models with more biologically oriented models (e.g. GSIM), has offered an answer to this need. The various BLMs which have been developed and/or refined for a number of metals (e.g. Cu, Ag, Zn) and species (algae, crustaceans, fish) are discussed here. Finally, the potential of the BLM approach is illustrated through a theoretical exercise in which chronic zinc toxicity to Daphnia magna is predicted in three regions, taking the physico-chemical characteristics of these areas into account.

  3. Pollutants bioavailability and toxicological risk from microplastics to marine mussels.

    Science.gov (United States)

    Avio, Carlo Giacomo; Gorbi, Stefania; Milan, Massimo; Benedetti, Maura; Fattorini, Daniele; d'Errico, Giuseppe; Pauletto, Marianna; Bargelloni, Luca; Regoli, Francesco

    2015-03-01

    Microplastics represent a growing environmental concern for the oceans due to their potential of adsorbing chemical pollutants, thus representing a still unexplored source of exposure for aquatic organisms. In this study polyethylene (PE) and polystyrene (PS) microplastics were shown to adsorb pyrene with a time and dose-dependent relationship. Results also indicated a marked capability of contaminated microplastics to transfer this model PAH to exposed mussels Mytilus galloprovincialis; tissue localization of microplastics occurred in haemolymph, gills and especially digestive tissues where a marked accumulation of pyrene was also observed. Cellular effects included alterations of immunological responses, lysosomal compartment, peroxisomal proliferation, antioxidant system, neurotoxic effects, onset of genotoxicity; changes in gene expression profile was also demonstrated through a new DNA microarray platform. The study provided the evidence that microplastics adsorb PAHs, emphasizing an elevated bioavailability of these chemicals after the ingestion, and the toxicological implications due to responsiveness of several molecular and cellular pathways to microplastics.

  4. New data on the bioavailability of bread magnesium.

    Science.gov (United States)

    Lopez, H W; Leenhardt, F; Remesy, C

    2004-12-01

    Whole cereal products are the main source of magnesium in human nutrition. Even if wholemeal bread is an important source of Mg, it also contains considerable amounts of phytic acid (PA), a natural chelator that lowers the absorption of trace elements such as Fe or Zn as well as Ca or Mg in cereal products. Significant Mg bioavailability improvement in bread could be supplied by the choice of raw materials and the baking processes of cereals. Improvement in the Mg content of wheat grain was proved possible by traditional plant selection. Bread making using sourdough improves the nutritional properties of bread by reducing the amounts of phytic acid and phytate breakdown, which is mainly explained by the acidity level in the sourdough process that promotes greater efficiency in the wheat phytase activity. A slight acidification due to sourdough effectively reduces the phytate content and improves Mg bioavaibility.

  5. ROLE OF MELT EXTRUSION IN THE ENHANCEMENT OF BIOAVAILABILITY

    Directory of Open Access Journals (Sweden)

    Sahil Bansode* and S. S. Poddar

    2012-11-01

    Full Text Available Starting from plastic industry, today melt extrusion has found its place in the array of pharmaceutical manufacturing processes. Melt extrusion processes are currently applied in the pharmaceutical field for the formulation of variety of dosage forms such as granules, pellets, tablets, implants, transdermal systems & ophthalmic inserts. This technology represents an efficient pathway for increasing the solubility of poorly soluble drugs. The process forms a solid dispersion where the drug is presented in an amorphous & molecularly dispersed state in a carrier. This leads to an increase in solubility, as no lattice energy has to be overcome during dissolution. Melt extrusion is considered to be an efficient technology in the field of formulation of solid dispersions to improve bioavailability with particular advantages over solvent processes. This article highlights on the technology of Hot Melt Extrusion (HME.

  6. Microbial bioavailability regulates organic matter preservation in marine sediments

    Directory of Open Access Journals (Sweden)

    K. A. Koho

    2012-09-01

    Full Text Available Burial of organic matter (OM plays an important role in marine sediments, linking the short-term, biological carbon cycle with the long-term, geological subsurface cycle. It is well established that low-oxygen conditions promote organic carbon burial in marine sediments. However, the mechanism remains enigmatic. Here we report biochemical quality, microbial degradability, OM preservation and accumulation along an oxygen gradient in the Indian Ocean. Our results show that more OM, and of biochemically higher quality, accumulates under low oxygen conditions. Nevertheless, microbial degradability does not correlate with the biochemical quality of OM. This decoupling of OM biochemical quality and microbial degradability, or bioavailability, violates the ruling paradigm that higher quality implies higher microbial processing. The inhibition of bacterial OM remineralisation may play an important role in the burial of organic matter in marine sediments and formation of oil source rocks.

  7. Overview of metabolism and bioavailability enhancement of polyphenols.

    Science.gov (United States)

    Lewandowska, Urszula; Szewczyk, Karolina; Hrabec, Elżbieta; Janecka, Anna; Gorlach, Sylwia

    2013-12-18

    A proper diet is one of major factors contributing to good health and is directly related to general condition of the organism. Phenolic compounds are abundant in foods and beverages (fresh and processed fruits and vegetables, leguminous plants, cereals, herbs, spices, tea, coffee, wine, beer) and their pleiotropic biological activities result in numerous health beneficial effects. On the other hand, high reactivity and very large diversity in terms of structure and molecular weight renders polyphenols one of the most difficult groups of compounds to investigate, as evidenced by ambiguous and sometimes contradictory results of many studies. Furthermore, phenolics undergo metabolic transformations, which significantly change their biological activities. Here, we discuss some aspects of metabolism and absorption of phenolic compounds. On the basis of information reported in the literature as well as in summaries of clinical trials and patent applications, we also give an overview of strategies for enhancing their bioavailability.

  8. Improving tenoxicam solubility and bioavailability by cosolvent system.

    Science.gov (United States)

    Yeh, Ming-Kung; Chang, Li-Chien; Chiou, Andy Hong-Jey

    2009-01-01

    The formulation study of tenoxicam, a poorly water-soluble drug, was developed by use of a ternary cosolvent system and has significantly enhanced the solubility. Additionally, the relative bioavailability of testing formulation was also evaluated by New Zealand rabbit with a single i.m. injection. The three-phase diagram for dimethylsulfoxide (DMSO)/propylene glycol/water, DMSO/ethanol/water, and DMSO/polyethoxylated castor oil/ethanol system was developed. The volume ratio of 5:4:1 in the DMSO/polyethoxylated castor oil/ethanol system resulted in a more suitable vehicle than other systems, with a high solubility (20.73 mg/ml) and low viscosity (10.0 Cp). A pharmacokinetic study of bioequivalence (F (rel) = 0.89) was also obtained. The present study not only provides a novel strategy improving tenoxicam solubility but also helps further scientific knowledge for the development of parenteral formulations.

  9. The Impact of Polymeric Nanoencapsulation on the Bioavailability of Lutein

    Science.gov (United States)

    Kamil, Alison

    Lutein, a fat-soluble xanthophyll, contributes partially to the health benefits from consuming plant foods. Like all dietary carotenoids, lutein has a low bioavailability. In addition to increasing the intake of lutein-rich foods to enhance lutein status, delivery of lutein in polymeric nanoparticles (NP) presents a novel approach to enhancing lutein bioavailability. The overall research objective of this project was to investigate, in rats, the impact of nanoencapsulation using poly(lactic-co-glycolic acid) (PLGA) on the pharmacokinetics of lutein. We also used an in vitro cell culture approach utilizing human epithelial colorectal adenocarcinoma (Caco-2) cells grown in both conventional (CONV) and permeable support (PS) systems to investigate the impact of PLGA-NP on the absorption of lutein in intestinal cells. In chapter one, we compared the efficacy of lutein absorption in vitro using Caco-2 cells grown in both CONV and PS systems. We further examined the role of the micelle, the physiological vehicle for lutein within the small intestine, on its intestinal absorption in vitro compared to an organic solvent, ethanol, which is safe and consumed by humans. The finding from this study demonstrated that the CONV system displayed a larger efficacy of lutein uptake by Caco-2 cells. Further, in the PS system, micelle components appeared to facilitate more effective intestinal secretion of lutein. These findings suggest that lutein uptake by Caco-2 cells is subject to the influence of culturing system (CONV vs. PS) and delivery vehicle (ethanol vs. micelle). Chapter two examined the impact of PLGA-NP in rats on lutein pharmacokinetics in plasma and distribution in selected tissues as compared to free lutein. We also investigated the effect of nanoencapsulation on the absorption of lutein in intestinal cells compared to a more physiological vehicle, the micelle, using the PS method. In addition, we explored the need of additional micelles for the ultimate absorption of

  10. Food effect on bioavailability of modified-release trimetazidine tablets.

    Science.gov (United States)

    Ozbay, Latif; Unal, Durisehvar Ozer; Erol, Dilek

    2012-10-01

    This study aimed to investigate a food effect on the bio-availability of modified-release (MR) trimetazidine tablets in 36 healthy volunteers. Trimetazidine, an anti-ischemic drug, protects the myocardial cell from the harmful effects of ischemia. The authors investigated the effect of being under a fasting or fed state at the time of drug intake on the bioavailability of trimetazidine 35-mg MR tablets in a randomized, open-label, crossover, 2-arm, 4-period, 2-sequence bioequivalence study design with a 14-day washout period. Plasma concentration of trimetazidine was assayed in timed samples with a validated high- performance liquid chromatography/mass selective detector that had a lower limit of quantification of 2.5 ng/mL. Test and reference formulations gave a mean trimetazidine C(max) of 63.26 ng/mL and 69.18 ng/mL for the fasting state and 64.19 ng/mL and 63.11 ng/mL for the fed state, respectively. The AUC(0-tlast) mean of trimetazidine was 726.31 ng·h/mL and 733.01 ng·h/mL for the fasting state and 706.40 ng·h/mL and 691.40 ng·h/mL for the fed state for test/reference formulations. There were no significant differences in pharmacokinetic parameters between the 2 formulations and the fasting/fed states. The authors showed that there is no food effect and no need for a 4-period study to evaluate the bioequivalence of trimetazidine MR tablets.

  11. BIOAVAILABILITY AND PHARMACOKINETICS OF ANASTROZOLE IN HEALTHY MALE VOLUNTEERS

    Institute of Scientific and Technical Information of China (English)

    安富荣; 崔岚; 刘晓琰; 王平全; 祝德秋; 曹惠明

    2002-01-01

    Objective To evaluate bioavailability and pharmacokinetics of domestic and imported anastrozole tablets. Methods Twenty Chinese healthy male volunteers were enrolled in a randomized crossover study with a single oral dose of 2mg of the two formulations respectively. The anastrozole in plasma was measured by gas chromatography with electron-capture detection. The linear range was 1. 325 ~ 106ng /ml plasma. The extraction recovery rates for plasma concentration of 5.3, 21.2 and 53. Ong/ml were 76.8% ,87.0% and 78.7%, respectively. Inter-day and intra-day precisions of the method were < 9%. Area under concentration-time curve ( AUCo t) , maximum plasma concentration (Cmax) and reach peak time (Tmax) were evaluated by variance analysis and two one-side t-test . Results A two-compartment model was adopted in anastrozole plasma concentration-time data analysis. The main pharmacokinetic parameters of domestic and imported anastrozloe tablets such as Cmax , Tmax, AUCo - t and T1/2β were (36.5 ± 6.9)ng/ml and (35.6 ± 9.4)ng/ml, (1.56-±0.41)hand(1.53 ±0.49)h, (1403.6 ± 321.2)ng'h/mland (1371.6±329.4)ng'h/mi, (42.57 ± 10.15)h and (43.41 ± 8.59)h, respectively, and there were no significant differences between the two formulations. Conclusion Domestic and imported anastrozole tablets were of bioequivalence.The relative bioavailability of the domestic tablet was (102.7 ± 5.6)%.

  12. Zinc and iron bioavailability of genetically modified soybeans in rats.

    Science.gov (United States)

    Martino, H S D; Martin, B R; Weaver, C M; Bressan, J; Esteves, E A; Costa, N M B

    2007-11-01

    The aim of this work was to evaluate zinc and iron bioavailability of UFV-116, a new variety without 2 lipoxygenases, with better taste and flavor than a commercial variety OCEPAR 19, containing all 3 isozymes. To evaluate zinc absorption using 65Zn whole body retention and femur 65Zn uptake, rats were given 3 g of a 65ZnCl2 labeled test meal (0.25 microCi). The 2 varieties were tested at the level of 9 and 30 ppm of zinc as defatted soy flour. Two other groups (control) received egg white as source of protein and ZnS04.H20 as the zinc source. To evaluate iron absorption, using 59Fe whole body retention, animals were given a 3 g 59FeCl3 labeled test meal (0.2 microCi). The 2 varieties were tested at 12 and 25 ppm iron as defatted soy flour. Whole fat soy flour of variety 1 (UFV-116) was higher (P phytic acid, and oxalate than variety 2 (OCEPAR-19). No difference was observed among the soybean varieties (P > 0.05) for femur 65Zn retention, at different levels of zinc. However, whole body retention was lower (P < 0.05) for UFV-116 than for OCEPAR-19. Femur 65Zn uptake was correlated with the whole body retention; however, whole body retention was more sensitive. Whole body 59Fe retention from UFV-116 was lower (P < 0.05) than from OCEPAR-19. Zinc and iron bioavailability was lower for UFV-116, possibly due to its higher content of antinutrient factors, especially phytate.

  13. Use of Tunable Whole-Cell Bioreporters to Assess Bioavailable Cadmium and Remediation Performance in Soils.

    Directory of Open Access Journals (Sweden)

    Youngdae Yoon

    Full Text Available It is important to have tools to measure the bioavailability to assess the risks of pollutants because the bioavailability is defined as the portions of pollutants showing the biological effects on living organisms. This study described the construction of tunable Escherichia coli whole-cell bioreporter (WCB using the promoter region of zinc-inducible operon and its application on contaminated soils. It was verified that this WCB system showed specific and sensitive responses to cadmium rather than zinc in the experimental conditions. It was inferred that Cd(II associates stronger with ZntR, a regulatory protein of zinc-inducible operon, than other metal ions. Moreover, the expression of reporter genes, egfp and mcherry, were proportional to the concentration of cadmium, thereby being a quantitative sensor to monitor bioavailable cadmium. The capability to determine bioavailable cadmium was verified with Cd(II amended LUFA soils, and then the applicability on environmental systems was investigated with field soils collected from smelter area in Korea before and after soil-washing. The total amount of cadmium was decreased after soil washing, while the bioavailability was increased. Consequently, it would be valuable to have tools to assess bioavailability and the effectiveness of soil remediation should be evaluated in the aspect of bioavailability as well as removal efficiency.

  14. Soil parameters are key factors to predict metal bioavailability to snails based on chemical extractant data

    Energy Technology Data Exchange (ETDEWEB)

    Pauget, B.; Gimbert, F., E-mail: frederic.gimbert@univ-fcomte.fr; Scheifler, R.; Coeurdassier, M.; Vaufleury, A. de

    2012-08-01

    Although soil characteristics modulate metal mobility and bioavailability to organisms, they are often ignored in the risk assessment of metal transfer. This paper aims to determine the ability of chemical methods to assess and predict cadmium (Cd), lead (Pb) and zinc (Zn) environmental bioavailability to the land snail Cantareus aspersus. Snails were exposed in the laboratory for 28 days to 17 soils from around a former smelter. The soils were selected for their range of pH, organic matter, clay content, and Cd, Pb and Zn concentrations. The influence of soil properties on environmental availability (estimated using HF-HClO{sub 4}, EDTA, CaCl{sub 2}, NH{sub 4}NO{sub 3}, NaNO{sub 3}, free ion activity and total dissolved metal concentration in soil solution) and on environmental bioavailability (modelled using accumulation kinetics) was identified. Among the seven chemical methods, only the EDTA and the total soil concentration can be used to assess Cd and Pb environmental bioavailability to snails (r Superscript-Two {sub adj} = 0.67 and 0.77, respectively). For Zn, none of the chemical methods were suitable. Taking into account the influence of the soil characteristics (pH and CEC) allows a better prediction of Cd and Pb environmental bioavailability (r Superscript-Two {sub adj} = 0.82 and 0.83, respectively). Even though alone none of the chemical methods tested could assess Zn environmental bioavailability to snails, the addition of pH, iron and aluminium oxides allowed the variation of assimilation fluxes to be predicted. A conceptual and practical method to use soil characteristics for risk assessment is proposed based on these results. We conclude that as yet there is no universal chemical method to predict metal environmental bioavailability to snails, and that the soil factors having the greatest impact depend on the metal considered. - Highlights: Black-Right-Pointing-Pointer New approach to identify chemical methods able to predict metal bioavailability

  15. Environmental behaviour and bioavailability of Depleted Uranium (DU) material

    Energy Technology Data Exchange (ETDEWEB)

    Oeh, U.; Gerstmann, U.; Schimmack, W.; Szymczak, W.; Li, W.B.; Hoellriegl, V.; Roth, P.; Paretzke, H.G. [GSF - National Research Center for Environment and Health, Inst. of Radiation Protection, Neuherberg (Germany)

    2005-07-01

    This work was performed to assess a possible health risk of depleted uranium (DU) for residents and KFOR personnel serving on the Balkans. Therefore, the environmental behaviour and bioavailability of DU material have been explored. In order to investigate the environmental impact of DU ammunition, leaching experiments were carried out. DU penetrators were buried in soil filled in columns. The soil was irrigated (16 mm/week) and the uranium isotopes {sup 238}U and {sup 235}U which were washed out and transported into the eluate were determined by inductively coupled plasma mass spectrometry (ICP-MS). After one year, an average of 1.7% of the original DU material corroded. About 40% of the corrosion products were located on the surface of the penetrator, 60% were recovered in the soil. On the other hand, only very small amounts of the DU material could be found in the eluate (about 1 ppm per year) suggesting a low solubility of DU and the corrosion products and/or a strong sorption to the soil. In another part of the study, the solubility of DU material in human body fluids was investigated to assess the bioavailability after oral intake and inhalation of DU particles. Therefore, DU corrosion products were powdered and incubated in artificial gastric juice and simulated lung fluid. About three-fourths of the DU material was dissolved in artificial gastric juice after 30 minutes. This fraction could not be increased, even when the incubation time was extended to 120 minutes. The dissolution of DU material in artificial lung fluid showed a distinct bi-phasic course with a readily soluble fraction and a fraction of very low solubility. These findings suggest that the DU corrosion products consist mainly of two types of uranium oxides, hexavalent and fast soluble compounds and tetravalent compounds with low solubility. Additional measurements with time-of-flight secondary ion mass spectrometry (TOF-SIMS) of DU corrosion material support this conclusion. The resulting

  16. Amine functionalized cubic mesoporous silica nanoparticles as an oral delivery system for curcumin bioavailability enhancement

    Science.gov (United States)

    Budi Hartono, Sandy; Hadisoewignyo, Lannie; Yang, Yanan; Meka, Anand Kumar; Antaresti; Yu, Chengzhong

    2016-12-01

    In the present work, a simple method was used to develop composite curcumin-amine functionalized mesoporous silica nanoparticles (MSN). The nanoparticles were used to improve the bioavailability of curcumin in mice through oral administration. We investigated the effect of particle size on the release profile, solubility and oral bioavailability of curcumin in mice, including amine functionalized mesoporous silica micron-sized-particles (MSM) and MSN (100-200 nm). Curcumin loaded within amine functionalized MSN (MSN-A-Cur) had a better release profile and a higher solubility compared to amine MSM (MSM-A-Cur). The bioavailability of MSN-A-Cur and MSM-A-Cur was considerably higher than that of ‘free curcumin’. These results indicate promising features of amine functionalized MSN as a carrier to deliver low solubility drugs with improved bioavailability via the oral route.

  17. Dissolution and bioavailability of lercanidipine-hydroxypropylmethyl cellulose nanoparticles with surfactant.

    Science.gov (United States)

    Ha, Eun-Sol; Choo, Gwang-Ho; Baek, In-hwan; Kim, Jung-Soo; Cho, Wonkyung; Jung, Young Suk; Jin, Su-Eon; Hwang, Sung-Joo; Kim, Min-Soo

    2015-01-01

    The objective of this study was to develop lercanidipine-hydroxypropylmethyl cellulose (HPMC) nanoparticles with high oral bioavailability. The lercanidipine-HPMC nanoparticles with/without surfactants were manufactured using a supercritical antisolvent (SAS) process. Gelucire 44/14, poloxamer 407, and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) were evaluated as surfactants. Spherical lercanidipine-HPMC nanoparticles with a mean particle size less than 400 nm were successfully prepared using a SAS process. The dissolution and oral bioavailability of lercanidipine was significantly increased by addition of surfactants. Especially lercanidipine-HPMC nanoparticles with TPGS showed a 2.47-fold higher oral bioavailability than raw material. Furthermore, the dissolution efficiency was strongly correlated to the in vivo Cmax and AUC0 → 24h. Therefore, the preparation of HPMC nanoparticles with TPGS using a SAS process is a highly effective formulation strategy for enhanced oral bioavailability of lercanidipine.

  18. Assessing the bioavailability and risk from metal-contaminated soils and dusts

    Science.gov (United States)

    Exposure to contaminated soil and dust is an important pathway in human health risk assessment. Physical and chemical characteristics, as well as biological factors, determine the bioaccessibility/bioavailability of soil and dust contaminants. Within a single sample, contaminat...

  19. Caddisflies as biomonitors identifying thresholds of toxic metal bioavailability that affect the stream benthos.

    Science.gov (United States)

    Rainbow, Philip S; Hildrew, Alan G; Smith, Brian D; Geatches, Tim; Luoma, Samuel N

    2012-07-01

    It has been proposed that bioaccumulated concentrations of toxic metals in tolerant biomonitors be used as indicators of metal bioavailability that could be calibrated against the ecological response to metals of sensitive biotic assemblages. Our hypothesis was that metal concentrations in caddisfly larvae Hydropsyche siltalai and Plectrocnemia conspersa, as tolerant biomonitors, indicate metal bioavailability in contaminated streams, and can be calibrated against metal-specific ecological responses of mayflies. Bioaccumulated concentrations of Cu, As, Zn and Pb in H. siltalai from SW English streams were related to the mayfly assemblage. Mayflies were always sparse where bioavailabilities were high and were abundant and diverse where bioavailabilities of all metals were low, a pattern particularly evident when the combined abundance of heptageniid and ephemerellid mayflies was the response variable. The results offer promise that bioaccumulated concentrations of metals in tolerant biomonitors can be used to diagnose ecological impacts on stream benthos from metal stressors.

  20. Chemical composition and effects of micronized corn bran on iron bioavailability in rats

    Directory of Open Access Journals (Sweden)

    Gilson Irineu de Oliveira Junior

    2014-09-01

    Full Text Available The degermination of corn grains by dry milling generates 5% of a fibrous residue. After segregation and micronization, corn bran becomes a potential source of dietary fiber consumption. However, its effect on iron bioavailability has not been reported in the literature. The objective of the present study was to determine the nutritional composition of corn bran and its effects on iron bioavailability using the hemoglobin depletion-repletion method in rats. The animals were divided into two groups: cellulose (control and corn bran (experimental. The bran had high content of total dietary fiber, especially the insoluble fraction, and low phytate content. Hemoglobin uptake did not differ between groups at the end of repletion period, and the iron relative bioavailability value of the corn bran diet was 104% in comparison to that of the control group. The product evaluated proved to be a potential source of dietary fiber and it showed no negative effects on iron bioavailability.

  1. STUDIES ON BIOREMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBON-CONTAMINATED SEDIMENTS: BIOAVAILABILITY, BIODEGRADABILITY, AND TOXICITY ISSUES

    Science.gov (United States)

    The widespread contamination of aquatic sediments by polycyclic aromatic hydrocarbons (PAHs) has created a need for cost-effective bioremediation processes, on which the bioavailability and the toxicity of PAHs often have a significant impact. This research investigated the biode...

  2. Dual partitioning and attachment effects of rhamnolipid on pyrene biodegradation under bioavailability restrictions

    NARCIS (Netherlands)

    Congiu, E.; Parsons, J.R.; Ortega-Calvo, J.J.

    2015-01-01

    We investigated the effects of different bioavailability scenarios on the rhamnolipid-enhanced biodegradation of pyrene by the representative polycyclic aromatic hydrocarbon degrader Mycobacterium gilvum VM552. This biosurfactant enhanced biodegradation when pyrene was provided in the form of solid

  3. Physicochemical properties and oral bioavailability of ursolic acid nanoparticles using supercritical anti-solvent (SAS) process.

    Science.gov (United States)

    Yang, Lei; Sun, Zhen; Zu, Yuangang; Zhao, Chunjian; Sun, Xiaowei; Zhang, Zhonghua; Zhang, Lin

    2012-05-01

    The objective of the study was to prepare ursolic acid (UA) nanoparticles using the supercritical anti-solvent (SAS) process and evaluate its physicochemical properties and oral bioavailability. The effects of four process variables, pressure, temperature, drug concentration and drug solution flow rate, on drug particle formation during SAS process, were investigated. Particles with mean particle size ranging from 139.2±19.7 to 1039.8±65.2nm were obtained by varying the process parameters. The UA was characterised by scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, thermal gravimetric analysis, specific surface area, dissolution test and bioavailability test. It was concluded that physicochemical properties and bioavailability of crystalline UA could be improved by physical modification, such as particle size reduction and generation of amorphous state using SAS process. Further, SAS process was a powerful methodology for improving the physicochemical properties and bioavailability of UA.

  4. Lead Speciation and Bioavailability in Apatite-Amended Sediments

    Directory of Open Access Journals (Sweden)

    Kirk G. Scheckel

    2011-01-01

    Full Text Available The in situ sequestration of lead (Pb in sediment with a phosphate amendment was investigated by Pb speciation and bioavailability. Sediment Pb in preamendment samples was identified as galena (PbS with trace amounts of absorbed Pb. Sediment exposed to atmospheric conditions underwent conversion to hydrocerussite and anglesite. Sediments mixed with apatite exhibited limited conversion to pyromorphite, the hypothesized end product. Conversion of PbS to pyromorphite is inhibited under reducing conditions, and pyromorphite formation appears limited to reaction with pore water Pb and PbS oxidation products. Porewater Pb values were decreased by 94% or more when sediment was amended with apatite. The acute toxicity of the sediment Pb was evaluated with Hyalella azteca and bioaccumulation of Pb with Lumbriculus variegatus. The growth of H. azteca may be mildly inhibited in contaminated sediment, with apatite-amended sediments exhibiting on average a higher growth weight by approximately 20%. The bioaccumulation of Pb in L. variegatus tissue decreased with increased phosphate loading in contaminated sediment. The study indicates limited effectiveness of apatite in sequestering Pb if present as PbS under reducing conditions, but sequestration of porewater Pb and stabilization of near-surface sediment may be a feasible and alternative approach to decreasing potential toxicity of Pb.

  5. Bioavailability of a potato chromium complex to the laboratory rat

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, H.K.

    1985-01-01

    Research objectives were to study the effect of food source, preparation method and chemical form on bioavailability of chromium. Chromium concentration in potatoes was determined and tubers labeled either intrinsically or extrinsically with radioactive chromate. A labeled chromium complexes was isolated from preparations of raw, baked or fried potatoes and chromatographed on gel permeation media. Availability of the potato chromium complex to the rat was examined in three feeding studies. Animals were dosed with radioactive extrinsically or intrinsically labeled potato extract or with chromate. A labeled chromium complex was isolated from gastrointestinal contents of rats and chromatographed. Potato pulp and peel contained 1.63 and 2.70 ..mu..g Cr/g tissue respectively. True and apparent absorption from extrinsically labeled feedings were 33.4 +/- 4.7 and 29.8 +/- 11.2% respectively, and no differences existed between absorption from raw and cooked potatoes. Absorption from the extrinsic labeled potatoes differed significantly from absorption of inorganic chromatium. Apparent absorption of raw (11.1 +/- 7.9%) and cooked (-0.7 +/- 2.8%) intrinsically labeled feedings differed significantly. Absorption of inorganic chromium was 17.8% (true) and 11.5% (apparent). Examination of the chromium complex isolated from gastrointestinal tract contents showed enlargement of the complex in the stomach after consumption.

  6. Bioavailability of zinc in marine systems through time

    Science.gov (United States)

    Scott, Clint; Planavsky, Noah J.; Dupont, Chris L.; Kendall, Brian; Gill, Benjamin C.; Robbins, Leslie J.; Husband, Kathryn F.; Arnold, Gail L.; Wing, Boswell A.; Poulton, Simon W.; Bekker, Andrey; Anbar, Ariel D.; Konhauser, Kurt O.; Lyons, Timothy W.

    2013-02-01

    The redox state of the oceans strongly influences the concentration of dissolved trace metals in sea water. Changes in the redox state of the oceans are thought to have limited the availability of some trace metals in the past, particularly during the Proterozoic eon, 2,500 to 542 million years ago. Of these trace metals, zinc (Zn) is of particular importance to eukaryotic organisms, because it is essential for a wide range of basic cellular functions. It has been suggested that during the Proterozoic, marine environments were broadly euxinic--that is, anoxic and sulphidic--which would have resulted in low Zn availability. Low Zn bioavailability could therefore be responsible for an observed delay in eukaryote diversification. Here we present a compilation of Zn abundance data from black shales deposited under euxinic conditions from the Precambrian time to the present. We show that these values track first-order trends in seawater Zn availability. Contrary to previous estimates, we find that Zn concentrations during the Proterozoic were similar to modern concentrations, supporting recent studies that call for limited euxinia at this time. Instead, we propose that predominantly anoxic and iron-rich deep oceans, combined with large hydrothermal fluxes of Zn, maintained high levels of dissolved Zn throughout the oceans. We thus suggest that the protracted diversification of eukaryotic Zn-binding proteins was not a result of Znbiolimitation.

  7. Advances in the analysis of iminocyclitols: Methods, sources and bioavailability.

    Science.gov (United States)

    Amézqueta, Susana; Torres, Josep Lluís

    2016-05-01

    Iminocyclitols are chemically and metabolically stable, naturally occurring sugar mimetics. Their biological activities make them interesting and extremely promising as both drug leads and functional food ingredients. The first iminocyclitols were discovered using preparative isolation and purification methods followed by chemical characterization using nuclear magnetic resonance spectroscopy. In addition to this classical approach, gas and liquid chromatography coupled to mass spectrometry are increasingly used; they are highly sensitive techniques capable of detecting minute amounts of analytes in a broad spectrum of sources after only minimal sample preparation. These techniques have been applied to identify new iminocyclitols in plants, microorganisms and synthetic mixtures. The separation of iminocyclitol mixtures by chromatography is particularly difficult however, as the most commonly used matrices have very low selectivity for these highly hydrophilic structurally similar molecules. This review critically summarizes recent advances in the analysis of iminocyclitols from plant sources and findings regarding their quantification in dietary supplements and foodstuffs, as well as in biological fluids and organs, from bioavailability studies.

  8. Dietary bioavailability of Cu adsorbed to colloidal hydrous ferric oxide

    Science.gov (United States)

    Cain, Daniel J.; Croteau, Marie-Noële; Fuller, Christopher C.

    2013-01-01

    The dietary bioavailability of copper (Cu) adsorbed to synthetic colloidal hydrous ferric oxide (HFO) was evaluated from the assimilation of 65Cu by two benthic grazers, a gastropod and a larval mayfly. HFO was synthesized, labeled with 65Cu to achieve a Cu/Fe ratio comparable to that determined in naturally formed HFO, and then aged. The labeled colloids were mixed with a food source (the diatom Nitzschia palea) to yield dietary 65Cu concentrations ranging from 211 to 2204 nmol/g (dry weight). Animals were pulse fed the contaminated diet and assimilation of 65Cu from HFO was determined following 1–3 days of depuration. Mass transfer of 65Cu from HFO to the diatom was less than 1%, indicating that HFO was the source of 65Cu to the grazers. Estimates of assimilation efficiency indicated that the majority of Cu ingested as HFO was assimilated (values >70%), implying that colloidal HFO potentially represents a source of dietary Cu to benthic grazers, especially where there is active formation and infiltration of these particles into benthic substrates.

  9. Phytic acid reduction in soy protein improves zinc bioavailability

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, J.R.; Wong, M.S.; Burns, R.A.; Erdman, J.W. Jr. (Univ. of Illinois, Urbana (United States) Mead Johnson Research Center, Evansville, IN (United States))

    1991-03-15

    The objective of this study was to confirm previous studies that have suggested that reduction of phytic acid in soy improved zinc bioavailability (BV). Two commercially-produced soybean isolates containing either a normal phytic acid level or a reduced level were formulated into diets so as to provide 6 or 9 ppm zinc. Control diets were egg white protein-based and contained 3, 6 or 9 ppm zinc from zinc carbonate. Weanling male rats were fed these diets for 21 days and food intake and weight gain monitored. Slope ratio analysis of total tibia zinc content compared to total zinc intake revealed that zinc BV from reduced phytic acid soy isolate-containing diets was indistinguishable from control egg white diets. In contrast, zinc BV from normal soy isolate diets was significantly reduced compared to reduced phytic acid and control diets. These results coupled with other results indicate that phytic acid is the inhibitory factor in soybean products that results in reduced zinc BV.

  10. Enhancing oral bioavailability of quercetin using novel soluplus polymeric micelles

    Science.gov (United States)

    Dian, Linghui; Yu, Enjiang; Chen, Xiaona; Wen, Xinguo; Zhang, Zhengzan; Qin, Lingzhen; Wang, Qingqing; Li, Ge; Wu, Chuanbin

    2014-12-01

    To improve its poor aqueous solubility and stability, the potential chemotherapeutic drug quercetin was encapsulated in soluplus polymeric micelles by a modified film dispersion method. With the encapsulation efficiency over 90%, the quercetin-loaded polymeric micelles (Qu-PMs) with drug loading of 6.7% had a narrow size distribution around mean size of 79.00 ± 2.24 nm, suggesting the complete dispersibility of quercetin in water. X-ray diffraction (XRD) patterns illustrated that quercetin was in amorphous or molecular form within PMs. Fourier transform infrared spectroscopy (FTIR) indicated that quercetin formed intermolecular hydrogen bonding with carriers. An in vitro dialysis test showed the Qu-PMs possessed significant sustained-release property, and the formulation was stable for at least 6 months under accelerated conditions. The pharmacokinetic study in beagle dogs showed that absorption of quercetin after oral administration of Qu-PMs was improved significantly, with a half-life 2.19-fold longer and a relative oral bioavailability of 286% as compared to free quercetin. Therefore, these novel soluplus polymeric micelles can be applied to encapsulate various poorly water-soluble drugs towards a development of more applicable therapeutic formulations.

  11. Toxicokinetics and absolute oral bioavailability of melamine in broiler chickens.

    Science.gov (United States)

    Poapolathep, S; Klangkaew, N; Arreesrisom, P; Isariyodom, S; Sugita-Konishi, Y; Kumagai, S; Poapolathep, A

    2015-02-01

    The objective of this study was to investigate the toxicokinetic characteristics of melamine in broilers due to the limited information available for livestock. Melamine was then administered to broiler chickens at an intravenous (i.v.) or oral (p.o.) dosage of 5.5 mg/kg of body weight, and plasma samples were collected up to 48 h. The concentration of melamine in each plasma sample was analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Melamine was measurable up to 24 h after i.v. and p.o. administration. A one-compartment model was developed to describe the toxicokinetics of melamine in broilers. Following i.v. administration, the values for the elimination half-life (t(1/2β)), the volume of distribution (Vd ), and the clearance (CL) were 4.42 ± 1.02 h, 00.52 ± 0.18 L/kg, and 0.08 ± 0.01 L/h/kg, respectively. The absolute oral bioavailability (F) was 95.63 ± 3.54%. The results suggest that most of the administered melamine is favorably absorbed from the alimentary tract and rapidly cleared by the kidneys in broiler chickens.

  12. Glucosamine enhances paracetamol bioavailability by reducing its metabolism.

    Science.gov (United States)

    Qinna, Nidal A; Shubbar, Maryam H; Matalka, Khalid Z; Al-Jbour, Nawzat; Ghattas, Mohammad A; Badwan, Adnan A

    2015-01-01

    Paracetamol has an extensive first-pass metabolism that highly affects its bioavailability (BA); thus, dose may be repeated several times a day in order to have longer efficacy. However, hepatotoxicity may arise because of paracetamol metabolism. Therefore, this project aimed to increase paracetamol BA in rats by glucosamine (GlcN). At GlcN-paracetamol racemic mixture ratio of 4:1 and paracetamol dose of 10 mg/kg, paracetamol area under the curve (AUC) and maximum concentration (Cmax ) were significantly increased by 99% and 66%, respectively (p < 0.05). Furthermore, paracetamol AUC and Cmax levels were increased by 165% and 88% in rats prefed with GlcN for 2 days (p < 0.001). Moreover, GlcN significantly reduced phase Ι and phase I/ΙΙ metabolic reactions in liver homogenate by 48% and 54%, respectively. Furthermore, GlcN molecule was found to possess a good in silico binding mode into the CYP2E1 active site-forming bidentate hydrogen bonding with the Thr303 side chain. Finally, serum ALT and AST levels of rats-administered high doses of paracetamol were significantly reduced when rats were prefed with GlcN (p < 0.01). In conclusion, GlcN can increase the relative BA of paracetamol through reducing its metabolism. This phenomenon is associated with reduction in hepatocytes injury following ingestion of high doses of paracetamol.

  13. Variability of bioavailability and intestinal absorption mechanisms of metoprolol.

    Science.gov (United States)

    Fukao, Miki; Ishida, Kazuya; Horie, Asuka; Taguchi, Masato; Nozawa, Takashi; Inoue, Hiroshi; Hashimoto, Yukiya

    2014-01-01

    We previously reported that aging and/or cytochrome P450 2D6 polymorphism are responsible for the interindividual variability in the systemic clearance (CL) and bioavailability (F) of metoprolol. The aim of the present study was to evaluate the residual variability of F of metoprolol in routinely treated Japanese patients and to investigate the intestinal absorption mechanism of the drug using human intestinal epithelial LS180 cells. We first re-analyzed the blood concentration data for metoprolol in 34 Japanese patients using a nonlinear mixed effects model. The oral clearance (CL/F) of metoprolol was positively correlated with the apparent volume of distribution (V/F), suggesting the residual variability of F. The uptake of metoprolol into LS180 cells was significantly decreased by the acidification of extracellular medium pH, and was dependent on temperature and intracellular pH. Furthermore, the cellular uptake of metoprolol was saturable, and was significantly decreased in the presence of hydrophobic cationic drugs such as diphenhydramine, procainamide, bisoprolol, and quinidine. These findings indicate that residual variability of F is one of the causes of the interindividual pharmacokinetic variability of metoprolol, and that the interindividual variability of not only presystemic first-pass metabolism, but also intestinal absorption, may be responsible for the variable F of the drug.

  14. Pyrimethamine nanosuspension with improved bioavailability: in vivo pharmacokinetic studies.

    Science.gov (United States)

    Dhapte, Vividha; Kadam, Vivek; Pokharkar, Varsha

    2013-10-01

    Pyrimethamine is a standard antiprotozoal drug recommended for prophylaxis and treatment of malarial infections. Limited bioavailability, slow onset of action, and life-threatening side effects restrict its use. Hence, in the present study, pyrimethamine nanosuspension was prepared with the objective to improve its dissolution rate and pharmacokinetic profile. Stable pyrimethamine nanosuspension with submicron particle size was prepared by nanoprecipitation and high-pressure homogenization techniques. Nanosizing and stabilizers modified the surface characteristics of drug particles resulting in considerable increase in the dissolution rate. The in vivo pharmacokinetic studies of the prepared nanosuspension were carried out and compared with plain pyrimethamine suspension and marketed pyrimethamine suspension. The in vivo pharmacokinetic profiling of pyrimethamine nanosuspension in rats showed higher AUC0-24 h and C max compared to the plain and marketed pyrimethamine suspensions. In contrast to its plain and marketed formulation, pyrimethamine nanosuspension showed rapid onset of action (T max 0.5 h vs. 2 h). Also, the low volume of distribution and reduced elimination half-life of the developed nanosuspension can lead to reduced side effects. Thus, improved in vitro-in vivo kinetics indicated that nanosuspension proved to be a suitable strategy for elevating the therapeutic profile of pyrimethamine.

  15. Comparison of lutein bioavailability from vegetables and supplement.

    Science.gov (United States)

    Riso, Patrizia; Brusamolino, Antonella; Ciappellano, Salvatore; Porrini, Marisa

    2003-05-01

    Lutein is a carotenoid present in dark green leafy vegetables and it may be involved in the prevention of several diseases related to oxidative stress. The aim of this study was to evaluate bioavailability of lutein from different food sources (150 g spinach and 200 g broccoli) and a supplement in oil (300 mg VEGEX), all providing about 9 mg lutein. Eight healthy females were instructed to eat a low-carotenoid diet for the period of experimentation. On three different occasions, three weeks apart, volunteers ate the lutein sources together with 10 g olive oil and 40 g bread. Blood samples were collected just before eating, every two hours for 12 hours, and at 24, 32, 56, 80 and 104 hours. Lutein concentration increased significantly after six to eight hours and peaked after 10-12 hours, with the highest concentration reached after VEGEX intake. Lutein concentration remained significantly elevated for up to 80 hours (VEGEX and spinach). On the whole, our results suggest that the intake of one single dose of lutein from different sources is able to bring about a significant plasma response in the short term.

  16. Ranitidine: single dose pharmacokinetics and absolute bioavailability in man.

    Science.gov (United States)

    van Hecken, A M; Tjandramaga, T B; Mullie, A; Verbesselt, R; de Schepper, P J

    1982-08-01

    1 Ranitidine single dose pharmacokinetics and absolute bioavailability have been studied in five healthy male volunteers. Following an overnight fast, 150 mg was given intravenously as a bolus injection or orally as a tablet formulation to each subject on separate occasions. 2 Following intravenous administration, plasma levels declined biexponentially. The mean (+/- s.d.) distribution half-life (t 1/2 alpha) was 6.6 +/- 1.6 min; plasma half-life (t 1/2 beta) was 1.7 +/- 0.2 h; the volume of distribution (V) was 96 +/- 9 1; total body clearance (CL) was 647 +/- 94 ml/min and renal clearance (CLR) 520 +/- 123 ml/min. 3 Following oral administration plasma levels showed a bimodal pattern with a first peak at 1.1 +/- 0.4 h and a second peak at 3 +/- 0 h. The absolute availability was 60 +/- 17%. The plasma half-life (t 1/2) of 2.3 +/- 0.4 h was significantly longer (P less than 0.05) after oral than after i.v. administration. 4 Renal excretion of unchanged ranitidine accounted for 79 +/- 9% of the dose after i.v. administration and for 27 +/- 7% after oral administration. 5 Our results suggest a more extensive biotransformation of ranitidine and biliary excretion of metabolites after oral administration while i.v. administration ranitidine is preferentially excreted unchanged in the urine.

  17. Bioavailability of phenols from a phenol-enriched olive oil.

    Science.gov (United States)

    Suárez, Manuel; Valls, Rosa M; Romero, Maria-Paz; Macià, Alba; Fernández, Sara; Giralt, Montse; Solà, Rosa; Motilva, Maria-José

    2011-12-01

    Phenolic compounds are one of the main reasons behind the healthy properties of virgin olive oil (VOO). However, their daily intake from VOO is low compared with that obtained from other phenolic sources. Therefore, the intake of VOO enriched with its own phenolic compounds could be of interest to increase the daily dose of these beneficial compounds. To evaluate the effectiveness of enrichment on their bioavailability, the concentration of phenolic compounds and their metabolites in human plasma (0, 60, 120, 240 and 300 min) from thirteen healthy volunteers (seven men and six women, aged 25 and 69 years) was determined after the ingestion of a single dose (30 ml) of either enriched virgin olive oil (EVOO) (961·17 mg/kg oil) or control VOO (288·89 mg/kg oil) in a cross-over study. Compared with VOO, EVOO increased plasma concentration of the phenol metabolites, particularly hydroxytyrosol sulphate and vanillin sulphate (P phenols are highly dependent on the individual.

  18. Gastro retentive microencapsulated Cefpodoxime Proxetil to improve oral bioavailability

    Institute of Scientific and Technical Information of China (English)

    Deepa Karthikeyan; Karthikeyan M

    2009-01-01

    Objective:The objective of the present study was to develop floating microspheres of Cefpodoxime Proxetil in order to achieve an extended retention in the upper GIT,which may result in enhanced absorption and there by improved bioavailability.Methods:The microspheres were prepared by non -aqueous solvent evaporation method using polymers such as Hydroxyl Propyl Methyl Cellulose (HPMC K15M),Ethyl Cellulose (EC)in different ratios,and Cefpodoxime Proxetil contain in each formulation.In vitro drug release were performed by USP apparatus type I andthe microspheres were characterized by calculating percentage yield,particle size a-nalysis,buoyancy percentage,drug entrapment efficiencyand in vitro drug release studies.Results:The result showed microspheres yield were 50.50 %-72.21 %,particle size were distributed between75-600 μm,drug entrapment efficiency were 14.1 %-28.2 %,buoyancy percentage were 70.10 %-88.25 %.Conclusion:Cefpodoxime Proxetil floating microspheres,at the lower polymer to drug ratio,there was a significant drug re-lease.The better drug release profile was seen with FA2 with ratio of drug polymer (1∶2).

  19. Bioavailability of radiostrontium in soil: Experimental study and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Sysoeva, A.A. [Russian Institute of Agricultural Radiology and Agroecology, 249032 Obninsk (Russian Federation)]. E-mail: lab22@riarae.obninsk.org; Konopleva, I.V. [Russian Institute of Agricultural Radiology and Agroecology, 249032 Obninsk (Russian Federation); Sanzharova, N.I. [Russian Institute of Agricultural Radiology and Agroecology, 249032 Obninsk (Russian Federation)

    2005-07-01

    Parameters related to {sup 90}Sr mobility in the soil-plant system are reported: exchangeable content, selectivity coefficient, and transfer factor. Large mobility of {sup 90}Sr in different soil types was shown. The fraction of exchangeable {sup 90}Sr varied between 70 and 90%. The selectivity coefficient K {sub C}({sup 90}Sr/Ca) values were in the range 1.3-2.5. The radionuclide transfer factors (TF) varied by a factor of 9.6 for barley seedlings and by a factor of 6.6 for lupine seedlings. The exchangeable Ca content was the determinant soil parameter responsible for differences in {sup 90}Sr biological availability. A static model was devised that describes {sup 90}Sr sorption from soil solution by soil and on the root surface. The parameter of {sup 90}Sr bioavailability (A) has been suggested. Parameter A was calculated from data on soil exchangeable Ca content and {sup 90}Sr mobility indicators - exchangeable fraction of the radionuclide and the selectivity coefficient K {sub C}({sup 90}Sr/Ca). A correlation was found between TF and parameter A.

  20. Bioavailability and bioaccessibility of petroleum hydrocarbons in contaminated site soils

    Energy Technology Data Exchange (ETDEWEB)

    Stephenson, G.; Angell, R.; Strive, E.; Ma, W. [Stantec Consulting Ltd., Surrey, BC (Canada)

    2010-07-01

    Although the bioavailability and/or bioaccessibility of contaminants in soil can be measured by various ecological receptors, the methods that are suitable for metals do not necessarily work well for petroleum hydrocarbons (PHCs). In this study, several biological and chemical methods were used at various PHC contaminated sites to find the most fitting method for different soil types in terms of predicting the biological responses of organisms as measured by standard single species toxicity tests. Organisms such as plants, earthworms, and collembolan were exposed to soils with different PHC concentrations. Multiple endpoints were then measured to evaluate the biological responses. The exposure concentrations for the 4 CCME hydrocarbon fractions were measured using hexane:acetone extraction as well as extractions with cyclodextrin, and a mixture of enzymes to simulate the gastro-intestinal fluid of an earthworm. The estimated exposure concentrations depended on the extraction method. The study showed that existing methodologies must be modified in order to better estimate the biological effect of PHCs in soil. Comparative data was presented and discussed along with proposed methodological modifications.

  1. GARP regulates the bioavailability and activation of TGFβ.

    Science.gov (United States)

    Wang, Rui; Zhu, Jianghai; Dong, Xianchi; Shi, Minlong; Lu, Chafen; Springer, Timothy A

    2012-03-01

    Glycoprotein-A repetitions predominant protein (GARP) associates with latent transforming growth factor-β (proTGFβ) on the surface of T regulatory cells and platelets; however, whether GARP functions in latent TGFβ activation and the structural basis of coassociation remain unknown. We find that Cys-192 and Cys-331 of GARP disulfide link to the TGFβ1 prodomain and that GARP with C192A and C331A mutations can also noncovalently associate with proTGFβ1. Noncovalent association is sufficiently strong for GARP to outcompete latent TGFβ-binding protein for binding to proTGFβ1. Association between GARP and proTGFβ1 prevents the secretion of TGFβ1. Integrin α(V)β(6) and to a lesser extent α(V)β(8) are able to activate TGFβ from the GARP-proTGFβ1 complex. Activation requires the RGD motif of latent TGFβ, disulfide linkage between GARP and latent TGFβ, and membrane association of GARP. Our results show that GARP is a latent TGFβ-binding protein that functions in regulating the bioavailability and activation of TGFβ.

  2. Selenium Biochemistry and Bioavailability: Implications for Animal Agriculture

    Directory of Open Access Journals (Sweden)

    Shaniko Shini

    2015-12-01

    Full Text Available Selenium (Se is an essential trace mineral required for growth, development, immune function, and metabolism. Selenium exerts its biological effects as an integral component of selenoproteins (SePs. Deficiency or low Se status leads to marked changes in many biochemical pathways and a range of pathologies and disorders which are associated with SeP function. Animals, and presumably humans, are able to efficiently utilize nutritionally adequate levels of Se in both organic and inorganic forms. It is now clear that the bioavailability of Se varies depending on the source and chemical form of the Se supplement. There are a range of products available for dietary Se supplementation, however, organic sources have been shown to be assimilated more efficiently than inorganic compounds and are considered to be less toxic and more appropriate as a feed supplement. Yeast enriched with Selenohomoalanthionine (SeHLan has recently become commercially available, and initial research suggests that it may be an efficacious source for the production of Se enriched animal products.

  3. The bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens

    OpenAIRE

    Veldkamp, T.; Diepen, van, C.A.; Bikker, P.

    2014-01-01

    Zinc is an essential trace element for all farm animal species. It is commonly included in animal diets as zinc oxide, zinc sulphate or organically bound zinc. Umicore Zinc Chemicals developed zinc oxide products with different mean particle sizes. Umicore Zinc Chemicals requested Wageningen UR Livestock Research to determine the bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens. A precise estimate of the bioavailability of zinc sources is required both for fulf...

  4. Effects of aluminum hydroxide and calcium carbonate antacids on the bioavailability of ciprofloxacin.

    OpenAIRE

    Frost, R W; Lasseter, K C; Noe, A J; Shamblen, E C; Lettieri, J T

    1992-01-01

    This study was designed to determine the effects of an aluminum hydroxide antacid and a calcium carbonate antacid on the bioavailability of ciprofloxacin (Cipro). Cipro (750 mg) was administered orally to 12 healthy volunteers in a three-way randomized crossover design. The three treatments included Cipro alone, four 850-mg calcium carbonate tablets taken 5 min before Cipro, and three 600-mg aluminum hydroxide tablets taken 5 min before Cipro. The relative bioavailability of Cipro when given ...

  5. Monitoring bioavailable phosphorus in lotic systems: a polyphasic approach based on cyanobacteria.

    Science.gov (United States)

    Muñoz-Martín, M Ángeles; Martínez-Rosell, Aitor; Perona, Elvira; Fernández-Piñas, Francisca; Mateo, Pilar

    2014-03-15

    Conventional assays to measure phosphorus in freshwater systems are sometimes not sufficient to quantify the actual bioavailable P for aquatic biota since some inorganic or organic P species may not be detected by chemical methods, and their bioavailability can be affected by a range of environmental factors. This situation could lead regulatory agencies to be unable to detect imminent ecosystem-degrading phenomena such as cyanobacterial blooms. It could also be an obstacle in studying the ecophysiological requirements of freshwater communities. P bioavailability in five rivers located in central Spain was analysed by a polyphasic approach (combinations of different marker types) based on cyanobacteria. This approach included a parallel study with the use of a self-luminescent P-cyanobacterial bioreporter based on a phosphatase alkaline promoter, determination of in situ alkaline phosphatase activities from cyanobacteria found at sampling sites, and the characterisation of cyanobacterial morphological features related to P bioavailability (hairs, polyphosphate granules and calyptras). An inverse relationship was found between values of bioavailable P, measured by the bioreporter and phosphatase activities. Cyanobacteria from sampling sites with low bioavailable P showed high phosphatase activity and vice versa, although some differences in values of this activity were observed in different cyanobacteria found at the same place, in relation to different growth strategies. Morphological characteristics associated with P limitation or P enrichment also varied between sampling locations. Cyanobacteria collected from sampling sites with reduced P bioavailability, measured by bioreporter and phosphatase activity, had a lower abundance of polyphosphate granules; those cyanobacteria capable of developing hairs or calyptras showed a greater abundance of these structures. Conversely, polyphosphate granules in cyanobacteria increased as P bioavailability increased as measured

  6. Chemical composition and effects of micronized corn bran on iron bioavailability in rats

    OpenAIRE

    Gilson Irineu de Oliveira Junior; Neuza Maria Brunoro Costa; Hércia Stampini Duarte Martino; Maria Cristina Dias Paes

    2014-01-01

    The degermination of corn grains by dry milling generates 5% of a fibrous residue. After segregation and micronization, corn bran becomes a potential source of dietary fiber consumption. However, its effect on iron bioavailability has not been reported in the literature. The objective of the present study was to determine the nutritional composition of corn bran and its effects on iron bioavailability using the hemoglobin depletion-repletion method in rats. The animals were divided into two g...

  7. Influence of plant activity and phosphates on thorium bioavailability in soils from Baotou area, Inner Mongolia.

    Science.gov (United States)

    Guo, Pengran; Jia, Xiaoyu; Duan, Taicheng; Xu, Jingwei; Chen, Hangting

    2010-09-01

    Harm of thorium to living organisms is governed by its bioavailability. Thorium bioavailability in the soil-plant system of Baotou rare earth industrial area was studied using pot experiments of wheat and single extraction methods. The effects of wheat growth stage and phosphate on thorium bioavailability were also investigated. Based on extractabilities of various extraction methods (CaCl(2), NH(4)NO(3), EDTA, HOAc) and correlation analysis of thorium uptake by wheat plant and extractable thorium, a mixture of 0.02M EDTA+0.5M NH(4)OAc (pH 4.6) was found suitable for evaluation of thorium bioavailability in Baotou soil, which could be predicted quantitatively by multiple regression models. Because of differences of wheat root activities, thorium bioavailability in rhizosphere soil was higher than in bulk soil at tillering stage, but the reverse occurred at jointing stage. Phosphate addition induced the mineralization of soluble thorium by forming stable thorium phosphate compounds, and reduced thorium bioavailability in soil.

  8. Evaluating bioavailability of organic pollutants in soils by sequential ultrasonic extraction procedure.

    Science.gov (United States)

    Wu, Xiang; Zhu, Lizhong

    2016-08-01

    Under current retrospective risk assessment framework, the total concentrations of organic pollutants in soils have been employed as the standard for over 30 years. The total concentrations reflect the overall accumulation in soils but tend to be overly conservative for assessing the ecological risks, where the bioavailability plays an important role. In this study, the bioavailability of organic pollutants in soils was evaluated using a stepwise and tiered classification method, namely the sequential ultrasonic extraction procedure (SEUP). The water-soluble and acid-soluble fractions extracted by the SEUP were the bioavailable fractions. The reliability and environmental relevance of the speciation method were examined with representative organic pollutants using the root uptake methods and the semipermeable membrane devices (SPMDs). The plant uptake amounts corrected with weight were highly correlated with the bioavailable fractions (R(2) > 0.75). The amounts of the bioavailable fractions were negatively correlated with the logKow values (R(2) ranging from 0.71 to 0.77) of the organic pollutants and the contents of soil organic matter (R(2) ranging from 0.68 to 0.96). As a refinement of the current risk assessment framework, the SUEP that has proved to be a reliable and convenient is thus highly recommended for evaluating the bioavailability of organic pollutants in soils.

  9. Solid-state dependent dissolution and oral bioavailability of piroxicam in rats.

    Science.gov (United States)

    Lust, Andres; Laidmäe, Ivo; Palo, Mirja; Meos, Andres; Aaltonen, Jaakko; Veski, Peep; Heinämäki, Jyrki; Kogermann, Karin

    2013-01-23

    The aim of this study was to gain understanding about the effects of different solid-state forms of a poorly water-soluble piroxicam on drug dissolution and oral bioavailability in rats. Three different solid-state forms of piroxicam were studied: anhydrate I (AH), monohydrate (MH), and amorphous form in solid dispersion (SD). In addition, the effect of a new polymeric excipient Soluplus® (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer) on oral bioavailability of piroxicam was investigated. Significant differences in the dissolution and oral bioavailability were found between the solid-state forms of piroxicam. Amorphous piroxicam in SD showed the fastest dissolution in vitro and a solid-state transformation to MH in the dissolution medium. Despite the presence of solid-state transformation, SD exhibited the highest rate and extent of oral absorption in rats. Oral bioavailability of other two solid-state forms decreased in the order AH and MH. The use of Soluplus® was found to enhance the dissolution and oral bioavailability of piroxicam in rats. The present study shows the importance of solid-state form selection for oral bioavailability of a poorly water-soluble drug.

  10. Elevating bioavailability of curcumin via encapsulation with a novel formulation of artificial oil bodies.

    Science.gov (United States)

    Chang, Ming-Tsung; Tsai, Tong-Rong; Lee, Chun-Yann; Wei, Yu-Sheng; Chen, Ying-Jie; Chen, Chun-Ren; Tzen, Jason T C

    2013-10-09

    Utilization of curcumin has been limited due to its poor oral bioavailability. Oral bioavailability of hydrophobic compounds might be elevated via encapsulation in artificial seed oil bodies. This study aimed to improve oral bioavailability of curcumin via this encapsulation. Unfortunately, curcumin was indissoluble in various seed oils. A mixed dissolvent formula was used to dissolve curcumin, and the admixture was successfully encapsulated in artificial oil bodies stabilized by recombinant sesame caleosin. The artificial oil bodies of relatively small sizes (150 nm) were stably solidified in the forms of powder and tablet. Oral bioavailability of curcumin with or without encapsulation in artificial oil bodies was assessed in Sprague-Dawley male rats. The results showed that encapsulation of curcumin significantly elevated its bioavailability and provided the highest maximum whole blood concentration (Cmax), 37 ± 28 ng/mL, in the experimental animals 45 ± 17 min (t(max)) after oral administration. Relative bioavailability calculated on the basis of the area under the plasma concentration-time curve (AUC) was increased by 47.7 times when curcumin was encapsulated in the artificial oil bodies. This novel formulation of artificial oil bodies seems to possess great potential to encapsulate hydrophobic drugs for oral administration.

  11. Accounting for metal bioavailability in assessing water quality: A step change?

    Science.gov (United States)

    Merrington, Graham; Peters, Adam; Schlekat, Christian E

    2016-02-01

    Bioavailability of metals to aquatic organisms can be considered to be a combination of the physicochemical factors governing metal behavior and the specific pathophysiological characteristics of the organism's biological receptor. Effectively this means that a measure of bioavailability will reflect the exposures that organisms in the water column actually "experience". This is important because it has long been established that measures of total metal in waters have limited relevance to potential environmental risk. The concept of accounting for bioavailability in regard to deriving and implementing environmental water quality standards is not new, but the regulatory reality has lagged behind the development of scientific evidence supporting the concept. Practical and technical reasons help to explain this situation. For example, concerns remain from regulators and the regulated that the efforts required to change existing systems of metal environmental protection that have been in place for over 35 yr are so great as not to be commensurate with likely benefits. However, more regulatory jurisdictions are now considering accounting for metal bioavailability in assessments of water quality as a means to support evidence-based decision-making. In the past decade, both the US Environmental Protection Agency and the European Commission have established bioavailability-based standards for metals, including Cu and Ni. These actions have shifted the debate toward identifying harmonized approaches for determining when knowledge is adequate to establish bioavailability-based approaches and how to implement them.

  12. Dissolved organic matter composition and bioavailability reflect ecosystem productivity in the Western Arctic Ocean

    Science.gov (United States)

    Shen, Y.; Fichot, C. G.; Benner, R.

    2012-12-01

    Dissolved organic carbon (DOC) and total dissolved amino acids (TDAA) were measured in high (Chukchi Sea) and low (Beaufort Sea) productivity regions of the western Arctic Ocean to investigate the composition and bioavailability of dissolved organic matter (DOM). Concentrations and DOC-normalized yields of TDAA in Chukchi surface waters were relatively high, indicating an accumulation of bioavailable DOM. High concentrations and yields of TDAA were also observed in the upper halocline of slope and basin waters, indicating off-shelf transport of bioavailable DOM from the Chukchi Sea. In contrast, concentrations and yields of TDAA in Beaufort surface waters were relatively low, indicting DOM was of limited bioavailability. Concentrations and yields of TDAA in the upper halocline of slope and basin waters were also low, suggesting the Beaufort is not a major source of bioavailable DOM to slope and basin waters. In shelf waters of both systems, elevated concentrations and yields of TDAA were often observed in waters with higher chlorophyll concentrations and productivity. Surface concentrations of DOC were similar (p > 0.05) in the two systems despite the contrasting productivity, but concentrations and yields of TDAA were significantly higher (p productivity in the western Arctic. The occurrence of elevated bioavailable DOM concentrations in the Chukchi Sea implies an uncoupling between the biological production and utilization of DOM and has important implications for sustaining heterotrophic microbial growth and diversity in oligotrophic waters of the central Arctic basins.

  13. Influence of plant activity and phosphates on thorium bioavailability in soils from Baotou area, Inner Mongolia

    Energy Technology Data Exchange (ETDEWEB)

    Guo Pengran [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, 5625 Renmin Street, Changchun, Jilin 130022 (China); School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Jia Xiaoyu; Duan Taicheng; Xu Jingwei [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, 5625 Renmin Street, Changchun, Jilin 130022 (China); Chen Hangting, E-mail: guopengran@gmail.co [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, 5625 Renmin Street, Changchun, Jilin 130022 (China)

    2010-09-15

    Harm of thorium to living organisms is governed by its bioavailability. Thorium bioavailability in the soil-plant system of Baotou rare earth industrial area was studied using pot experiments of wheat and single extraction methods. The effects of wheat growth stage and phosphate on thorium bioavailability were also investigated. Based on extractabilities of various extraction methods (CaCl{sub 2}, NH{sub 4}NO{sub 3}, EDTA, HOAc) and correlation analysis of thorium uptake by wheat plant and extractable thorium, a mixture of 0.02 M EDTA + 0.5 M NH{sub 4}OAc (pH 4.6) was found suitable for evaluation of thorium bioavailability in Baotou soil, which could be predicted quantitatively by multiple regression models. Because of differences of wheat root activities, thorium bioavailability in rhizosphere soil was higher than in bulk soil at tillering stage, but the reverse occurred at jointing stage. Phosphate addition induced the mineralization of soluble thorium by forming stable thorium phosphate compounds, and reduced thorium bioavailability in soil.

  14. Towards bioavailability-based soil criteria: past, present and future perspectives.

    Science.gov (United States)

    Naidu, Ravi; Channey, Rufus; McConnell, Stuart; Johnston, Niall; Semple, Kirk T; McGrath, Steve; Dries, Victor; Nathanail, Paul; Harmsen, Joop; Pruszinski, Andrew; MacMillan, Janet; Palanisami, Thavamani

    2015-06-01

    Bioavailability has been used as a key indicator in chemical risk assessment yet poorly quantified risk factor. Worldwide, the framework used to assess potentially contaminated sites is similar, and the decisions are based on threshold contaminant concentration. The uncertainty in the definition and measurement of bioavailability had limited its application to environment risk assessment and remediation. Last ten years have seen major developments in bioavailability research and acceptance. The use of bioavailability in the decision making process as one of the key variables has led to a gradual shift towards a more sophisticated risk-based approach. Now a days, many decision makers and regulatory organisations 'more readily accept' this concept. Bioavailability should be the underlying basis for risk assessment and setting remediation goals of those contaminated sites that pose risk to environmental and human health. This paper summarises the potential application of contaminant bioavailability and bioaccessibility to the assessment of sites affected by different contaminants, and the potential for this to be the underlying basis for sustainable risk assessment and remediation in Europe, North America and Australia over the coming decade.

  15. Bioavailability enhanced rhizosphere remediation of petroleum hydrocarbon contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Marchenko, A.; Vorobyov, A.; Zharikov, G.; Ermolenko, Z.; Dyadishchev, N.; Borovick, R.; Sokolov, M. [Research Centre for Toxicology and Hygienic Regulation of Biopreparations, Moscow region (Russian Federation); Ortega-Calvo, J.J. [Instituto de Recursos Naturales y Agrobiologia, CSIC, Sevilla (Spain)

    2005-07-01

    Aliphatic, aromatic and polycyclic aromatic oil hydrocarbons are structurally complicated man-caused pollutants that are constantly brought into biosphere. Oil production in Russia, so as all over the world, is connected with pollution of biotopes, ecosystems and agro-landscapes. Presently large funds are allocated either for oil leak prevention or for discharged oil gathering. At the same time, in spite of large necessity in technologies for efficient reconstruction of soil bio-productivity, reliable regional systems of their remediation in situ have not been developed yet. One such method is rhizosphere remediation, a biotechnology, based on the functioning of plant-microbial complexes. Little is known about bioavailability in phyto-remediation systems. Specific bioavailability-promoting mechanisms, operating in soil with hydrocarbon-degrading populations, may be responsible for increased rates of pollutant transformation (increased bacterial adherence to the pollutants, production of bio-surfactants by bacteria or by plants, possible role of chemotaxis). In the course of work collection of 42 chemo-tactically active bio-surfactant producing strain-degraders of petroleum hydrocarbons including polycyclic aromatic hydrocarbons (PAHs) was created. Two representative strains were selected for detailed chemotaxis studies with PAHs (naphthalene, phenanthrene, anthracene, and pyrene), bacterial lipopolysaccharide and root exudates from seven different plants. These strains are produce the bio-surfactants (rhamno-lipid). The chemotactic response was quantified with a capillary and densitometric chemotaxis assay. Surface tension of cultural liquid was measured after cultivation of strains in the presence of hexadecane or phenanthrene with the use of a ring tensiometer. Before measuring of surface tension microbial cells were collected from liquid culture by centrifugation. Total petroleum Hydrocarbons (TPH) in soil were analyzed by infra-red spectroscopy method. PAHs

  16. Enhancement of Curcumin Bioavailability Using Nanocellulose Reinforced Chitosan Hydrogel

    Directory of Open Access Journals (Sweden)

    Thennakoon M. Sampath Udeni Gunathilake

    2017-02-01

    Full Text Available A unique biodegradable, superporous, swellable and pH sensitive nanocellulose reinforced chitosan hydrogel with dynamic mechanical properties was prepared for oral administration of curcumin. Curcumin, a less water-soluble drug was used due to the fact that the fast swellable, superporous hydrogel could release a water-insoluble drug to a great extent. CO2 gas foaming was used to fabricate hydrogel as it eradicates using organic solvents. Field emission scanning electron microscope images revealed that the pore size significantly increased with the formation of widely interconnected porous structure in gas foamed hydrogels. The maximum compression of pure chitosan hydrogel was 25.9 ± 1 kPa and it increased to 38.4 ± 1 kPa with the introduction of 0.5% cellulose nanocrystals. In vitro degradation of hydrogels was found dependent on the swelling ratio and the amount of CNC of the hydrogel. All the hydrogels showed maximum swelling ratios greater than 300%. The 0.5% CNC-chitosan hydrogel showed the highest swelling ratio of 438% ± 11%. FTIR spectrum indicated that there is no interaction between drug and ingredients present in hydrogels. The drug release occurred in non-Fickian (anomalous manner in simulated gastric medium. The drug release profiles of hydrogels are consistent with the data obtained from the swelling studies. After gas foaming of the hydrogel, the drug loading efficiency increased from 41% ± 2.4% to 50% ± 2.0% and release increased from 0.74 to 1.06 mg/L. The drug release data showed good fitting to Ritger-Peppas model. Moreover, the results revealed that the drug maintained its chemical activity after in vitro release. According to the results of this study, CNC reinforced chitosan hydrogel can be suggested to improve the bioavailability of curcumin for the absorption from stomach and upper intestinal tract.

  17. Bioavailability of radiocaesium in soil: parameterization using soil characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Syssoeva, A.A.; Konopleva, I.V. [Russian Institute of Agricultural Radiology and Agroecology, Obninsk (Russian Federation)

    2004-07-01

    It has been shown that radiocaesium availability to plants strongly influenced by soil properties. For the best evaluation of TFs it necessary to use mechanistic models that predict radionuclide uptake by plants based on consideration of sorption-desorption and fixation-remobilization of the radionuclide in the soil as well as root uptake processes controlled by the plant. The aim of the research was to characterise typical Russian soils on the basis of the radiocaesium availability. The parameter of the radiocaesium availability in soils (A) has been developed which consist on radiocaesium exchangeability; CF -concentration factor which is the ratio of the radiocaesium in plant to that in soil solution; K{sub Dex} - exchangeable solid-liquid distribution coefficient of radiocaesium. The approach was tested for a wide range of Russian soils using radiocaesium uptake data from a barley pot trial and parameters of the radiocaesium bioavailability. Soils were collected from the arable horizons in different soil climatic zones of Russia and artificially contaminated by {sup 137}Cs. The classification of soils in terms of the radiocaesium availability corresponds quite well to observed linear relationship between {sup 137}Cs TF for barley and A. K{sub Dex} is related to the soil radiocaesium interception potential (RIP), which was found to be positively and strongly related to clay and physical clay (<0,01 mm) content. The {sup 137}Cs exchangeability were found to be in close relation to the soil vermiculite content, which was estimated by the method of Cs{sup +} fixation. It's shown radiocaesium availability to plants in soils under study can be parameterized through mineralogical soil characteristics: % clay and the soil vermiculite content. (author)

  18. Intestinal Oxidative State Can Alter Nutrient and Drug Bioavailability

    Directory of Open Access Journals (Sweden)

    Faria Ana

    2009-01-01

    Full Text Available Organic cations (OCs are substances of endogenous (e.g., dopamine, choline or exogenous (e.g., drugs like cimetidine origin that are positively charged at physiological ph. since many of these compounds can not pass the cell membrane freely, their transport in or out of cells must be mediated by specific transport systems. Transport by organic cation transporters (OCTs can be regulated rapidly by altering their trafficking and/or affinities in response to stimuli. However, for example, a specific disease could lead to modifications in the expression of OCTs. Chronic exposure to oxidative stress has been suggested to alter regulation and functional activity of proteins through several pathways. According to results from a previous work, oxidation-reduction pathways were thought to be involved in intestinal organic cation uptake modulation. The present work was performed in order to evaluate the influence of oxidative stressors, especially glutathione, on the intestinal organic cation absorption. For this purpose, the effect of compounds with different redox potential (glutathione, an endogenous antioxidant, and procyanidins, diet antioxidants was assessed on MPP+ (1-methyl-4-phenylpyridinium iodide uptake in an enterocyte cell line (Caco-2. Caco-2 cells were subcultured with two different media conditions (physiological: 5 mM glucose, referred as control cells; and high-glucose: 25 mM glucose, referred as HG cells. In HG cells, the uptake was significantly lower than in control cells. Redox changing interventions affected Mpp+ uptake, both in control and in high-glucose Caco-2 cells. Cellular glutathione levels could have an important impact on membrane transporter activity. The results indicate that modifications in the cellular oxidative state modulate MPP+ uptake by Caco-2 cells. Such modifications may reflect in changes of nutrient and drug bioavailability.

  19. Bioavailability, pharmacokinetics and residues of chloramphenicol in the chicken.

    Science.gov (United States)

    Anadón, A; Bringas, P; Martinez-Larrañaga, M R; Diaz, M J

    1994-02-01

    The pharmacokinetic properties of chloramphenicol were determined in broiler chickens after two single oral doses (30 and 50 mg/kg body weight) and after a single intravenous (i.v.) dose (30 mg/kg body weight). After oral and i.v. administration, the plasma concentration-time graph was characteristic of a two-compartment open model. After oral administration (30 and 50 mg/kg), chloramphenicol was absorbed rapidly (time to maximal concentration of 0.72 or 0.60 h) and eliminated with a mean half-life (t1/2 beta) of 6.87 or 7.41 h, respectively. The bioavailability was 29% at 30 mg/kg chloramphenicol and 38% at 50 mg/kg chloramphenicol. Concentrations greater than 5 micrograms/ml were achieved at 15 min and persisted up to 2 or 4 h post-administration, respectively. Statistically significant differences between the two routes of administration were found for the pharmacokinetic variables, half-lives of both distribution and elimination phases (t1/2 alpha, t1/2 beta) and apparent volume of distribution [Vd(area)]. The mean t1/2 beta of chloramphenicol and i.v. administration was 5.23 h. Chloramphenicol was extensively metabolized into dehydrochloramphenicol (DH-CAP), nitrophenylaminopropanedione (NPAP) and nitroso-chloramphenicol (NO-CAP) derivatives. Residues of chloramphenicol (CAP) and the three metabolites DH-CAP, NPAP and NO-CAP in kidney, liver and muscle were measured in chickens that received an oral dose of 50 mg/kg once daily for 4 days. The results indicate that CAP and DH-CAP residues were cleared slowly and were at or below the detection limit of 0.005 microgram/ml within 12 days after dosing. However, at the time of slaughter (12 days), the NPAP and NO-CAP residues were detected in the tissue.

  20. Sorption-bioavailability nexus of arsenic and cadmium in variable-charge soils.

    Science.gov (United States)

    Bolan, Nanthi; Mahimairaja, Santiago; Kunhikrishnan, Anitha; Naidu, Ravi

    2013-10-15

    In this work, the nexus between sorption and bioavailability of arsenic (As) and cadmium (Cd) as affected by soil type, soil pH, ageing, and mobilizing agents were examined. The adsorption of As and Cd was examined using a number of allophanic and non-allophanic soils which vary in their charge components. The effect of pH and ageing on the bioavailability of As and Cd was examined using spiked soils in a plant growth experiment. The effect of phosphate (P)-induced mobility of As on its bioavailability was examined using a naturally contaminated sheep dip soil. The results indicated that the adsorption of both As and Cd varied amongst the soils, and the difference in Cd adsorption is attributed to the difference in surface charge. An increase in soil pH increased net negative charge by an average of 45.7 mmol/kg/pH thereby increasing cation (Cd) adsorption; whereas, the effect of pH on anion (As) adsorption was inconsistent. The bioavailability of As and Cd decreased by 3.31- and 2.30-fold, respectively, with ageing which may be attributed to increased immobilization. Phosphate addition increased the mobility and bioavailability of As by 4.34- and 3.35-fold, respectively, in the sheep dip soil. However, the net effect of P on As phytoavailability depends on the extent of P-induced As mobilization in soils and P-induced competition for As uptake by roots. The results demonstrate the nexus between sorption and bioavailability of As and Cd in soils, indicating that the effects of various factors on bioavailability are mediated through their effects on sorption reactions.

  1. Interactions between active pharmaceutical ingredients and excipients affecting bioavailability: impact on bioequivalence.

    Science.gov (United States)

    García-Arieta, Alfredo

    2014-12-18

    The aim of the present paper is to illustrate the impact that excipients may have on the bioavailability of drugs and to review existing US-FDA, WHO and EMA regulatory guidelines on this topic. The first examples illustrate that small amounts of sorbitol (7, 50 or 60mg) affect the bioavailability of risperidone, a class I drug, oral solution, in contrast to what is stated in the US-FDA guidance. Another example suggests, in contrast to what is stated in the US-FDA BCS biowaivers guideline, that a small amount of sodium lauryl sulphate (SLS) (3.64mg) affects the bioavailability of risperidone tablets, although the reference product also includes SLS in an amount within the normal range for that type of dosage form. These factors are considered sufficient to ensure that excipients do not affect bioavailability according to the WHO guideline. The alternative criterion, defined in the WHO guideline and used in the FIP BCS biowaivers monographs, that asserts that excipients present in generic products of the ICH countries do not affect bioavailability if used in normal amounts, is shown to be incorrect with an example of alendronate (a class III drug) tablets, where 4mg of SLS increases bioavailability more than 5-fold, although a generic product in the USA contains SLS. Finally, another example illustrates that a 2mg difference in SLS may affect bioavailability of a generic product of a class II drug, even if SLS is contained in the comparator product, and in all cases its amount was within the normal range. Therefore, waivers of in vivo bioequivalence studies (e.g., BCS biowaivers, waivers of certain dosage forms in solution at the time of administration and variations in the excipient composition) should be assessed more cautiously.

  2. Bioavailability of heavy metals in soils: definitions and practical implementation--a critical review.

    Science.gov (United States)

    Kim, Rog-Young; Yoon, Jeong-Ki; Kim, Tae-Seung; Yang, Jae E; Owens, Gary; Kim, Kwon-Rae

    2015-12-01

    Worldwide regulatory frameworks for the assessment and remediation of contaminated soils have moved towards a risk-based approach, taking contaminant bioavailability into consideration. However, there is much debate on the precise definition of bioavailability and on the standardization of methods for the measurement of bioavailability so that it can be reliably applied as a tool for risk assessment. Therefore, in this paper, we reviewed the existing definitions of heavy metal bioavailability in relation to plant uptake (phytoavailability), in order to better understand both the conceptual and operational aspects of bioavailability. The related concepts of specific and non-specific adsorption, as well as complex formation and organic ligand affinity were also intensively discussed to explain the variations of heavy metal solubility and mobility in soils. Further, the most frequently used methods to measure bioavailable metal soil fractions based on both chemical extractions and mechanistic geochemical models were reviewed. For relatively highly mobile metals (Cd, Ni, and Zn), a neutral salt solution such as 0.01 M CaCl2 or 1 M NH4NO3 was recommended, whereas a strong acid or chelating solution such as 0.43 M HNO3 or 0.05 M DTPA was recommended for strongly soil-adsorbed and less mobile metals (Cu, Cr, and Pb). While methods which assessed the free metal ion activity in the pore water such as DGT and DMT or WHAM/Model VI, NICA-Donnan model, and TBLM are advantageous for providing a more direct measure of bioavailability, few of these models have to date been properly validated.

  3. Evaluation of Iron Bioavailability in Caco-2 cell Culture Model: Modification of the Original Method

    Directory of Open Access Journals (Sweden)

    Bahareh Nikooyeh

    2016-07-01

    Full Text Available Background and Objectives: In the original in vitro method for evaluation of iron bioavailability using caco-2 cell model, ferritin formation by cells is considered as a functional indicator of both absorption and utilization of iron. However, as iron is measured in the tested material and then ferritin concentration is measured in caco-2 cell lysate, it is almost impossible to have a concrete measure of iron bioavailability because the percent of absorbable iron cannot be calculated by the concentration of iron in caco-2 cell lysate. To overcome this problem, the original method was modified by using ferrous sulfate tablet as a standard and also including blank well in the cell culture plate to subtract the baseline ferritin concentration from the ferritin concentration of other wells. Materials and Methods: To evaluate iron bioavailability in this model, one kind of Iranian traditional breads (Sangak was used. Standard curve was plotted using iron concentration and ferritin/protein ratio in the X and Y axes, respectively. Results: The standard curve showed a linear equation: Ferritin (ng/protein (mg = (5.96 × bread Fe+ 11.55, R2=0.989. Using this equation, the bioavailability of iron from the tested bread was 79.76 ± 11.5% of ferrous sulfate. Considering that the reported iron bioavailability from ferrous sulfate is about 10%, bioavailability of iron from the bread could be regarded 8%. Conclusions: This data can be potentially usable to adjust the amount of absorbable iron in the target population for fortification programs. Keywords: Iron, Bioavailability, Caco-2 cell

  4. Arsenic bioavailability in soils before and after soil washing: the use of Escherichia coli whole-cell bioreporters.

    Science.gov (United States)

    Yoon, Youngdae; Kang, Yerin; Chae, Yooeun; Kim, Sunghoon; Lee, Youngshim; Jeong, Seung-Woo; An, Youn-Joo

    2016-02-01

    We investigated the quantification of bioavailable arsenic in contaminated soils and evaluation of soil-washing processes in the aspect of bioavailability using a novel bacterial bioreporter developed in present study. The whole-cell bioreporter (WCB) was genetically engineered by fusing the promoter of nik operon from Escherichia coli and green fluorescent protein as a sensing domain and reporter domain. Among eight well-known hazardous heavy metals and metalloid, this system responded specifically to arsenic, thereby inferring association of As(III) with NikR inhibits the repression. Moreover, the response was proportional to the concentration of As(III), thereby it was capable to determine the amount of bioavailable arsenic quantitatively in contaminated soils. The bioavailable portion of arsenic was 5.9 (3.46-10.96) and 0.9 (0.27-1.74) % of total from amended and site soils, respectively, suggesting the bioavailability of arsenic in soils was related to the soil properties and duration of aging. On the other hand, only 1.37 (0.21-2.97) % of total arsenic was extracted into soil solutions and 19.88 (11.86-28.27) % of arsenic in soil solution was bioavailable. This result showed that the soluble arsenic is not all bioavailable and most of bioavailable arsenic in soils is water non-extractable. In addition, the bioavailable arsenic was increased after soil-washing while total amount was decreased, thereby suggesting the soil-washing processes release arsenic associated with soil materials to be bioavailable. Therefore, it would be valuable to have a tool to assess bioavailability and the bioavailability should be taken into consideration for soil remediation plans.

  5. Loading amorphous Asarone in mesoporous silica SBA-15 through supercritical carbon dioxide technology to enhance dissolution and bioavailability.

    Science.gov (United States)

    Zhang, Zhengzan; Quan, Guilan; Wu, Qiaoli; Zhou, Chan; Li, Feng; Bai, Xuequn; Li, Ge; Pan, Xin; Wu, Chuanbin

    2015-05-01

    The aim of this study was to load amorphous hydrophobic drug into ordered mesoporous silica (SBA-15) by supercritical carbon dioxide technology in order to improve the dissolution and bioavailability of the drug. Asarone was selected as a model drug due to its lipophilic character and poor bioavailability. In vitro dissolution and in vivo bioavailability of the obtained Asarone-SBA-15 were significantly improved as compared to the micronized crystalline drug. This study offers an effective, safe, and environmentally benign means of solving the problems relating to the solubility and bioavailability of hydrophobic molecules.

  6. Effects of polymer molecular weight on relative oral bioavailability of curcumin

    Directory of Open Access Journals (Sweden)

    Lin LC

    2012-06-01

    Full Text Available Yin-Meng Tsai,1 Wan-Ling Chang-Liao,1 Chao-Feng Chien,1 Lie-Chwen Lin,1,2 Tung-Hu Tsai,1,31Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, 2National Research Institute of Chinese Medicine, 3Department of Education and Research, Taipei City Hospital, Taipei, TaiwanBackground: Polylactic-co-glycolic acid (PLGA nanoparticles have been used to increase the relative oral bioavailability of hydrophobic compounds and polyphenols in recent years, but the effects of the molecular weight of PLGA on bioavailability are still unknown. This study investigated the influence of polymer molecular weight on the relative oral bioavailability of curcumin, and explored the possible mechanism accounting for the outcome.Methods: Curcumin encapsulated in low (5000–15,000 and high (40,000–75,000 molecular weight PLGA (LMw-NPC and HMw-NPC, respectively were prepared using an emulsification-solvent evaporation method. Curcumin alone and in the nanoformulations was administered orally to freely mobile rats, and blood samples were collected to evaluate the bioavailability of curcumin, LMw-NPC, and HMw-NPC. An ex vivo experimental gut absorption model was used to investigate the effects of different molecular weights of PLGA formulation on absorption of curcumin. High-performance liquid chromatography with diode array detection was used for quantification of curcumin in biosamples.Results: There were no significant differences in particle properties between LMw-NPC and HMw-NPC, but the relative bioavailability of HMw-NPC was 1.67-fold and 40-fold higher than that of LMw-NPC and conventional curcumin, respectively. In addition, the mean peak concentration (Cmax of conventional curcumin, LMw-NPC, and HMw-NPC was 0.028, 0.042, and 0.057 µg/mL, respectively. The gut absorption study further revealed that the HMw-PLGA formulation markedly increased the absorption rate of curcumin in the duodenum and resulted in excellent bioavailability

  7. PAH effects on meio- and microbial benthic communities strongly depend on bioavailability.

    Science.gov (United States)

    Lindgren, J Fredrik; Hassellöv, Ida-Maja; Dahllöf, Ingela

    2014-01-01

    The effects of anthropogenic pollutants in dissimilar habitats can vary depending on differences in bioavailability. The factors determining bioavailability are not yet fully understood. This study was performed to evaluate whether analysis of total PAH concentrations in sediments is a satisfactory measurement to indicate environmental effects or if bioavailability is needed to be taken into account. We have here performed a 60-day experiment, where nominal PAH concentrations of 1,300 μg/kg sediment were added to three different marine sediments. Meiofaunal and microbial communities were analyzed for alterations in community response at 30 and 60 days. Results showed that bioavailability of PAHs varied between the three different sediments. Nonetheless, the petroleum addition gave rise to significant negative effects on all three sediments at both time points. The two direct measurements of toxicity on the microbial community, potential nitrification and denitrification, displayed a lower effect of the PAH addition in the muddy sediment at both time points, compared to the other two sediment types. No effects were seen in the analysis of meiofaunal community structure. Measurements of PAH bioavailability in the three sediment types concurred with the results from the microbial community, revealing a lower bioavailability in the muddy sediment compared to the other two sediment types, 34% compared to sandy and 18% compared to organic at day 0. At day 60 it was 61% lower compared to sandy and 20% lower compared to organic. The negative effects of the PAH addition on the microbial nitrogen cycle were in six out of eight cases best correlated to the amount of alkylated bioavailable PAH in the sediments, and thus microbial nitrogen cycle is a possible good indicator for assessing PAH-induced stress. The results presented here have implications for risk analysis studies of petroleum-contaminated marine sediments; consequently, sediment characteristics and its effects on

  8. Bioavailability and toxicity of dietborne copper and zinc to fish

    Science.gov (United States)

    Clearwater, Susan J.; Farag, Aida M.; Meyer, J.S.

    2002-01-01

    To date, most researchers have used dietborne metal concentrations rather than daily doses to define metal exposure and this has resulted in contradictory data within and between fish species. It has also resulted in the impression that high concentrations of dietborne Cu and Zn (e.g.>900 mg kg−1 dry diet) are relatively non-toxic to fish. We re-analyzed existing data using rations and dietborne metal concentrations and used daily dose, species and life stage to define the toxicity of dietborne Cu and Zn to fish. Partly because of insufficient information we were unable to find consistent relationships between metal toxicity in laboratory-prepared diets and any other factor including, supplemented metal compound (e.g. CuSO4 or CuCl2), duration of metal exposure, diet type (i.e. practical, purified or live diets), or water quality (flow rates, temperature, hardness, pH, alkalinity). For laboratory-prepared diets, dietborne Cu toxicity occurred at daily doses of >1 mg kg−1 body weight d−1 for channel catfish (Ictalurus punctatus), 1–15 mg kg−1 body weight d−1 (depending on life stage) for Atlantic salmon (Salmo salar) and 35–45 mg kg−1 body weight d−1 for rainbow trout (Oncorhynchus mykiss). We found that dietborne Zn toxicity has not yet been demonstrated in rainbow trout or turbot (Scophthalmus maximus) probably because these species have been exposed to relatively low doses of metal (phytate and calcium on dietborne Zn bioavailability. We also explored a rationale to understand the relative importance of exposure to waterborne or dietborne Cu and Zn with a view to finding an approach useful to regulatory agencies. Contrary to popular belief, the relative efficiency of Cu uptake from water and diet is very similar when daily doses are compared rather than Cu concentrations in each media. The ratio of dietborne dose:waterborne dose is a good discriminator of the relative importance of exposure to dietborne or waterborne Zn. We discuss gaps in

  9. Carcinogenicity of azo colorants: influence of solubility and bioavailability.

    Science.gov (United States)

    Golka, Klaus; Kopps, Silke; Myslak, Zdislaw W

    2004-06-15

    In the past, azo colorants based on benzidine, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine (o-tolidine), and 3,3'-dimethoxybenzidine (o-dianisidine) have been synthesized in large amounts and numbers. Studies in exposed workers have demonstrated that the azoreduction of benzidine-based dyes occurs in man. The metabolic conversion of benzidine-, 3,3'-dimethylbenzidine- and 3,3'-dimethoxybenzidine-based dyes to their (carcinogenic) amine precursors in vivo is a general phenomenon that must be considered for each member of this class of chemicals. Several epidemiological studies have demonstrated that the use of the benzidine-based dyes has caused bladder cancer in humans. However, in contrast to water-soluble dyes, the question of biological azoreduction of (practically insoluble) pigments has been a matter of discussion. As a majority of azo pigments are based on 3,3'-dichlorobenzidine, much of the available experimental data are focused on this group. Long-term animal carcinogenicity studies performed with pigments based on 3,3'-dichlorobenzidine did not show a carcinogenic effect. The absence of a genotoxic effect has been supported by mutagenicity studies with the 3,3'-dichlorobenzidine-based Pigment Yellow 12. Studies in which azo pigments based on 3,3'-dichlorobenzidine had been orally administered to rats, hamsters, rabbits and monkeys could generally not detect significant amounts of 3,3'-dichlorobenzidine in the urine. It, therefore, appears well established that the aromatic amine components from azo pigments based on 3,3'-dichlorobenzidine are practically not bioavailable. Hence, it is very unlikely that occupational exposure to insoluble azo pigments would be associated with a substantial risk of (bladder) cancer in man. According to current EU regulations, azo dyes based on benzidine, 3,3'-dimethoxybenzidine and 3,3'-dimethylbenzidine have been classified as carcinogens of category 2 as "substances which should be regarded as if they are carcinogenic

  10. Assessment of bioavailability of heavy metal pollutants using soil isolates of Chlorella sp.

    Science.gov (United States)

    Krishnamurti, Gummuluru S R; Subashchandrabose, Suresh R; Megharaj, Mallavarapu; Naidu, Ravi

    2015-06-01

    Biotests conducted with plants are presently used to estimate metal bioavailability in contaminated soils. But when plants are grown in soils, especially the plants with fine roots, root collection is easily biased and tedious. Indeed, at harvest, small amounts of soil can adhere to roots, resulting in overestimation of root metal content, and the finest roots are often discarded from the analysis because of their difficult and almost impossible recovery. This report presents a novel method for assessing the bioavailability of heavy metals in soils using microalgae. Two species of green unicellular microalgae were isolated from two highly contaminated soils and identified by phylogenetic and molecular evolutionary analyses as Chlorella sp. RBM and Chlorella sp. RHM. These two cultures were used to determine the metal uptake from metal-contaminated soils of South Australia as a novel, cost-effective, simple and rapid method for assessing the bioavailability of heavy metals in soils. The suggested method is an attempt to achieve a realistic estimate of bioavailability which overcomes the inherent drawback of root metal contamination in the bioavailability indices so far reported.

  11. Periphyton: an important regulator in optimizing soil phosphorus bioavailability in paddy fields.

    Science.gov (United States)

    Wu, Yonghong; Liu, Junzhuo; Lu, Haiying; Wu, Chenxi; Kerr, Philip

    2016-11-01

    Periphyton is ubiquitous in paddy field, but its importance in influencing the bioavailability of phosphorus (P) in paddy soil has been rarely recognized. A paddy field was simulated in a greenhouse to investigate how periphyton influences P bioavailability in paddy soil. Results showed that periphyton colonizing on paddy soil greatly reduced P content in paddy floodwater but increased P bioavailability of paddy soil. Specifically, all the contents of water-soluble P (WSP), readily desorbable P (RDP), algal-available P (AAP), and NaHCO3-extractable P (Olsen-P) in paddy soil increased to an extent compared to the control (without periphyton) after fertilization. In particular, Olsen-P was the most increased P species, up to 216 mg kg(-1) after fertilization, accounting for nearly 60 % of total phosphorus (TP) in soil. The paddy periphyton captured P up to 1.4 mg g(-1) with Ca-P as the dominant P fraction and can be a potential crop fertilizer. These findings indicated that the presence of periphyton in paddy field benefited in improving P bioavailability for crops. This study provides valuable insights into the roles of periphyton in P bioavailability and migration in a paddy ecosystem and technical support for P regulation.

  12. Reduction of phytic acid in soybean products improves zinc bioavailability in rats.

    Science.gov (United States)

    Zhou, J R; Fordyce, E J; Raboy, V; Dickinson, D B; Wong, M S; Burns, R A; Erdman, J W

    1992-12-01

    The inhibitory effect of phytic acid in soybean products on zinc bioavailability was evaluated in two experiments in rats. In Experiment 1, soybean flours containing different natural phytic acid levels produced by sand culture techniques that limited phosphorus during growth of the soybean plants were formulated into diets. The rats fed a higher phytic acid level diet had lower food intake, depressed weight gain, and lower tibia zinc gain (P phytic acid level was found. In Experiment 2, two commercially produced soybean isolates containing either normal phytic acid level or a reduced level were formulated into diets. Slope ratio analysis revealed that relative zinc bioavailability from phytic acid-containing soybean isolate-based diets was significantly reduced (P phytic acid soybean isolate-containing diets resulted in a significant increase of zinc bioavailability compared with normal phytic acid diets (P phytic acid is the primary inhibitory factor in soybean products that results in reduced zinc bioavailability and that phytate reduction in soybean protein increases zinc bioavailability.

  13. Chemical extraction to assess the bioavailability of chlorobenzenes in soil with different aging periods

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yang; Wang, Fang; Yang, Xinglun; Liu, Cuiying; Jin, Xin; Jiang, Xin [Chinese Academy of Sciences, Nanjing (China). State Key Lab. of Soil and Sustainable Agriculture; Kengara, Fredrick Orori [Maseno Univ. (Kenya). Dept. of Chemistry

    2011-12-15

    Bioavailability is mainly influenced by aging and desorption of contaminants in soil. The purpose of this study was to investigate the desorption kinetics of chlorobenzenes (CBs) in soil and to investigate whether chemical extractions are suitable for the bioavailability assessment of CBs in soil. A soil spiked with CBs and aged for different periods was extracted with Tenax, hydroxypropyl-{beta}-cyclodextrin (HPCD), and butanol to assess the bioavailability of CBs in soil, respectively. Earthworm (Eisenia foetida) accumulation was used as bioassay in parallel experiments to evaluate the chemical extractions. The results showed that desorption of CBs from soil with consecutive Tenax extraction fitted into triphasic kinetics model. Different chemical methods extracted different amounts of CBs over different aging periods. For hexachlorobenzene (HCB), the extraction efficiency was in the order of butanol > Tenax-6h > HPCD extraction, while the order of butanol > HPCD > Tenax-6h extraction for pentachlorobenzene (PeCB). The bioaccumulation by earthworm decreased with increasing aging period and was significantly higher for HCB than for PeCB (p < 0.05). Earthworm accumulated CBs correlated well with all the three chemical extracted CBs. However, HPCD extraction showed the converse extraction tendency with earthworm uptake of CBs. Chemical extraction could be used to assess the bioavailability of contaminants in soil; however, they were method and compound specific. Tenax and butanol extractions were more reliable than HPCD extraction for bioavailability assessment of the tested CBs and the soil used since they showed the consistent extraction tendency with earthworm uptake of CBs.

  14. Interactions between sorption and biodegradation: Exploring bioavailability and pulsed nutrient injection efficiency

    Science.gov (United States)

    Phanikumar, M. S.; Hyndman, David W.

    2003-05-01

    Understanding the dynamics of sorption and bioavailability is crucial to the success of transport models as bioavailability often limits the complete bioremediation of contaminated soils. This paper examines the interplay between sorption and bioavailability with pulsed injection of nutrients based on a mechanistic model of microbially mediated reactive transport. We used a dimensionless parametric approach based on nondimensional groups such as the Damköhler and Peclet numbers to assess the relative importance of processes and rates. We consider case studies involving the biodegradation of carbon tetrachloride (CT) as well as a chemically induced degradation system to evaluate the effects of bioavailability. We first used these two cases to explore the effects of selectively activating the degradation terms in the aqueous and sorbed phases. The models for these two cases consistently predict that degradation is insensitive to retardation if degradation terms are not included for the sorbed phase. A specific mass removal rate was developed as an efficiency metric to explore the effects of pulsed nutrient injection on contaminant degradation and to estimate an optimal injection interval. The contaminant mass degraded per unit pumping was shown to be significantly higher for pulsed injection of substrates than with continuous injection. The presented results clearly indicate that considerations of bioavailability profoundly alter model predictions of degradation as well as parameter estimation results.

  15. Influence of Dissolved Organic Matter on Tetracycline Bioavailability to an Antibiotic-Resistant Bacterium.

    Science.gov (United States)

    Chen, Zeyou; Zhang, Yingjie; Gao, Yanzheng; Boyd, Stephen A; Zhu, Dongqiang; Li, Hui

    2015-09-15

    Complexation of tetracycline with dissolved organic matter (DOM) in aqueous solution could alter the bioavailability of tetracycline to bacteria, thereby alleviating selective pressure for development of antibiotic resistance. In this study, an Escherichia coli whole-cell bioreporter construct with antibiotic resistance genes coupled to green fluorescence protein was exposed to tetracycline in the presence of DOM derived from humic acids. Complexation between tetracycline and DOM diminished tetracycline bioavailability to E. coli, as indicated by reduced expression of antibiotic resistance genes. Increasing DOM concentration resulted in decreasing bioavailability of tetracycline to the bioreporter. Freely dissolved tetracycline (not complexed with DOM) was identified as the major fraction responsible for the rate and magnitude of antibiotic resistance genes expressed. Furthermore, adsorption of DOM on bacterial cell surfaces inhibited tetracycline diffusion into the bioreporter cells. The magnitude of the inhibition was related to the amount of DOM adsorbed and tetracycline affinity for the DOM. These findings provide novel insights into the mechanisms by which the bioavailability of tetracycline antibiotics to bacteria is reduced by DOM present in water. Agricultural lands receiving livestock manures commonly have elevated levels of both DOM and antibiotics; the DOM could suppress the bioavailability of antibiotics, hence reducing selective pressure on bacteria for development of antibiotic resistance.

  16. Preparation, Characterization and Evaluation of Quetiapine Fumarate Solid Lipid Nanoparticles to Improve the Oral Bioavailability

    Directory of Open Access Journals (Sweden)

    Arjun Narala

    2013-01-01

    Full Text Available Quetiapine fumarate is an antipsychotic drug with poor oral bioavailability (9% due to first-pass metabolism. Present work is an attempt to improve oral bioavailability of quetiapine fumarate by incorporating in solid lipid nanoparticles (SLN. Six quetiapine fumarate SLN formulations were developed using three different lipids by hot homogenisation followed by ultrasonication. The drug excipient compatibility was studied by differential scanning calorimetry (DSC. Stable quetiapine fumarate SLNs having a mean particle size of 200–250 nm with entrapment efficiency varying in between 80% and 92% were developed. The physical stability of optimized formulation F3 was checked at room temperature for 2 months. Comparative bioavailability studies were conducted in male Wistar rats after oral administration of quetiapine fumarate suspension and SLN formulation. The relative bioavailability of quetiapine fumarate from optimized SLN preparation was increased by 3.71 times when compared with the reference quetiapine fumarate suspension. The obtained results are indicative of SLNs as potential lipid carriers for improving the bioavailability of quetiapine fumarate by minimizing first-pass metabolism.

  17. Aging of triazine amine in soils demonstrated through sorption, desorption, and bioavailability measurements.

    Science.gov (United States)

    Godskesen, Berit; Holm, Peter E; Jacobsen, Ole S; Jacobsen, Carsten S

    2005-03-01

    The aging of triazine amine in soil was studied during a time course of 119 d by measuring bioavailability in terms of mineralization after inoculation of the triazine amine-degrading bacterium Rhodococcus erythropolis TA57. The bioavailability was measured in four soil samples: A-, B-, and C-horizons from an agricultural soil profile and in a peat soil. The sorption of triazine amine in the soil samples was quantified during the period of aging in terms of sorption distribution coefficients (Kd) and desorption distribution coefficients (Kd,des). Measures of bioavailability and triazine amine concentration in the nonavailable fraction showed effects of aging in the soils that were rich in organic matter. The triazine amine bioavailability declined significantly during the aging period in soils containing greater than 2% organic carbon, whereas the B- and C-horizons showed no signs of aging, in agreement with their low content of organic material. Corresponding to this, desorption decreased significantly in the A-horizon but, surprisingly, not in the peat soil. Analyses by thin-layer chromatography indicated an association of aqueous triazine amine and dissolved organic matter in the peat soil. This gives an explanation for both the significant decrease in bioavailability and the noncorresponding stability of the nonavailable (i.e., nondesorbed) fraction.

  18. Bioavailability of Fe and Zn in selected legumes, cereals, meat and milk products consumed in Fiji.

    Science.gov (United States)

    Singh, Poonam; Prasad, Surendra; Aalbersberg, William

    2016-09-15

    The present study reports contents and the bioavailability of Fe and Zn from 25 selected raw and cooked food samples. The results showed highest variation of Fe content in raw food samples ranging from 2.19 ± 0.04 to 0.93 ± 0.03 mg/100g in legumes. The raw black eye bean, cheese and fish showed high Zn content up to 8.85 ± 0.01, 12.93 ± 0.26 and 172.03 ± 5.09 mg/100g, respectively. Pulses and cereals showed high level of ionizable Fe. Zn bioavailability was quite low in cereals as compared to pulses; 4.02% in yellow split to 17.40% in Bengal gram. Zn bioavailability of 17.40% is in cheese. Fe bioavailability is high in cooked rice 160.60%, white bread 428.30% and milk powder 241.67% showing that Fe bioavailability increased after cooking whereas the lowest in fish 0.84%. The multivariate and cluster analysis categorized studied foods into two main groups.

  19. Development of lycopene micelle and lycopene chylomicron and a comparison of bioavailability

    Science.gov (United States)

    Jyun Chen, Yi; Inbaraj, Baskaran Stephen; Shiau Pu, Yeong; Chen, Bing Huei

    2014-04-01

    The objectives of this study were to develop lycopene micelles and lycopene chylomicrons from tomato extracts for the enhancement and comparison of bioavailability. Lycopene micelles and chylomicrons were prepared by a microemulsion technique involving tomato extract, soybean oil, water, vitamin E and surfactant Tween 80 or lecithin in different proportions. The encapsulation efficiency of lycopene was 78% in micelles and 80% in chylomicrons, with shape being roughly spherical and mean particle size being 7.5 and 131.5 nm. A bioavailability study was conducted in rats by both gavage and i.v. administration, with oral bioavailability of lycopene, phytoene and phytofluene being 6.8, 4.3 and 3.1% in micelles and 9.5, 9.4 and 7.1% in chylomicrons, respectively. This outcome reveals higher lycopene bioavailability through incorporation into micelle or chylomicron systems. Both size and shape should be considered for oral bioavailability determination. For i.v. injection, lycopene micelles should be more important than lycopene chylomicrons for future clinical applications.

  20. Impact of excipient interactions on drug bioavailability from solid dosage forms.

    Science.gov (United States)

    Panakanti, Ravikiran; Narang, Ajit S

    2012-10-01

    Excipients are generally pharmacologically inert, but can interact with drugs in the dosage form and the physiological factors at the site of absorption to affect the bioavailability of a drug product. A general mechanistic understanding of the basis of these interactions is essential to design robust drug products. This paper focuses on drug-excipient interactions in solid dosage forms that impact drug bioavailability, the drug substance and drug product properties affected by excipients, and the impact of excipients on physiologic processes. The extent to which drug bioavailability is affected by these interactions would vary on a case-by-case basis depending upon factors such as the potency and dose of the drug, therapeutic window, site of absorption, rate limiting factor in drug absorption (e.g., permeability or solubility limited), or whether drug metabolism, efflux, complexation, or degradation at the site of absorption play a role in determining its bioavailability. Nonetheless, a mechanistic understanding of drug-excipient interactions and their impact on drug release and absorption can help develop formulations that exhibit optimum drug bioavailability.

  1. Budgets for total and bioavailable nitrogen in the North Sea-Baltic Sea transition zone

    DEFF Research Database (Denmark)

    Jørgensen, L.; Markager, Stiig; Maar, Marie

    Budget calculations show that bioavailability of dissolved organic nitrogen (DON) is a key factor in management of eutrophication in open marine areas as it governs the importance of local loadings versus nitrogen received from adjacent seas and hence if eutrophication is a local or regional...... problem. Nitrogen is the limiting nutrient in the Belt Sea and the Kattegat. At the same time the area is heavily affected by eutrophication. Hence, a number of abatement measures have been implanted in Denmark, Sweden and Germany in order to reduce the anthropogenic nitrogen loadings. In this context...... it is essential to know how much of the nitrogen comes from local sources and how much is imported for the adjacent seas. We have therefore made nitrogen budgets for both total nitrogen and bioavailable nitrogen covering the area. Bioavailable nitrogen consists of inorganic N, particulate organic N...

  2. Relative bioavailability of the flavonoids quercetin, hesperetin and naringenin given simultaneously through diet

    DEFF Research Database (Denmark)

    Krogholm, Kirstine Suszkiewicz; Bredsdorff, Lea; Knuthsen, Pia

    2010-01-01

    The bioavailability and urinary excretion of three dietary flavonoids, quercetin, hesperetin and naringenin, were investigated. Ten healthy men were asked to consume a 'juice mix' containing equal amounts of the three flavonoids, and their urine and plasma samples were collected. The resulting mean...... plasma area under the curve (AUC)(0-48h) and C-max values for quercetin and hesperetin were similar, whereas the AUC(0-48h) of naringenin and, thus, the relative bioavailability were higher after consumption of the same dose. The study consolidates a significantly lower urinary excretion of quercetin (1.......5 +/- 1%) compared with hesperetin (14.2 +/- 9.1%) and naringenin (22.6 +/- 11.5%) and shows that this is not due to a lower bioavailability of quercetin, but rather reflects different clearance mechanisms. European Journal of Clinical Nutrition (2010) 64, 432-435; doi: 10.1038/ejcn.2010.6; published...

  3. The search for a new paradigm to study micronutrient and phytochemical bioavailability: from reductionism to holism.

    Science.gov (United States)

    Fardet, A; Rock, E

    2014-02-01

    The study of micronutrient and phytochemical (MaP, i.e., non-energy nutrients) bioavailability has been mainly studied through a reductionist and pharmacological approach. This has led to associate one health effect to one MaP. However, human interventional studies have given conflicting and disappointing results about MaP supplementation. This is because the health effect is the result of the synergetic action of numerous MaPs supplied by foods and/or diets at nutritional doses. A food is not a drug. Therefore, there is a need for more holistic approach to study MaP bioavailability, then their health effect to achieve general recommendations. This paper aims to hypothesize for such a paradigm shift in this topic and to lay new foundations for research in MaP bioavailability.

  4. Kinetic speciation and bioavailability of copper and nickel in mangrove sediments.

    Science.gov (United States)

    Chakraborty, Parthasarathi; Chakraborty, Sucharita; Ramteke, Darwin; Chennuri, Kartheek

    2014-11-15

    An attempt was made to establish a mechanistic linkage between chemical speciation of copper and nickel, and their bioavailability in mangrove ecosystem. Kinetic speciation study was performed to determine the concentrations of labile metal-complexes and their dissociation rate constants in mangrove sediments. Concentrations of copper and nickel in the mangrove roots were used as indicators of their bioavailability. It was found that the bioaccumulation of both the metals gradually increased with the increasing concentrations of the labile metal complexes and their dissociation rate constants in the mangrove sediments. This study shows that concentration of labile metal (copper and nickel) complexes and their dissociation rate constants in mangrove sediment can be a good indicator of their bioavailability.

  5. Complexation of Z-ligustilide with hydroxypropyl-β-cyclodextrin to improve stability and oral bioavailability

    Directory of Open Access Journals (Sweden)

    Lu Yapeng

    2014-06-01

    Full Text Available To improve the stability and oral bioavailability of Z-ligustilide (LIG, the inclusion complex of LIG with hydroxypropyl- β-cyclodextrin (HP-β-CD was prepared by the kneading method and characterized by UV-Vis spectroscopy, differential thermal analysis (DTA and Fourier transform infrared (FTIR spectroscopy. LIG is capable of forming an inclusion complex with HP-b-CD and the stoichiometry of the complex was 1:1. Stability of the inclusion complex against temperature and light was greatly enhanced compared to that of free LIG. Further, oral bioavailability of LIG and the inclusion complex in rats were studied and the plasma drug concentration-time curves fitted well with the non-compartment model to estimate the absolute bioavailability, which was 7.5 and 35.9 %, respectively. In conclusion, these results show that LIG/HP-β-CD complexation can be of great use for increasing the stability and biological efficacy of LIG

  6. EFFECT OF PHYTATECONTENTS OF CEREAL BY-PRODUCTS ON BIOAVAILABILITY OF TOT AL PHOSPHORUS IN POULTRY

    Directory of Open Access Journals (Sweden)

    Ishtiaq Ahmad

    2002-04-01

    Full Text Available Four cereal by-products were examined for their total and phytate phosphorus contents. Feeding trial for bioavailability was conducted on 18 weeks old cockerels of White Leg Horn breed which were starved for24 hours and were forced-fed 30 grams of finely ground single feedstuff and droppings were collected at pre-determined time intervals. The bioavailability of total phosphorus for wheat bran, rice polishing, wheat middling and gram kara was 37.11 , 15.37,61.32 and 62.64%, respectively while phytate phosphorus contents were 0.66, 1.16, 0.24 and 0.17%, respectively. The bioavailability of total phosphorus was negatively correlated with the phytate phosphorus contents of these feed stuffs (P< 0.01 .

  7. An exploration of the relationship between adsorption and bioavailability of pesticides in soil to earthworm

    Energy Technology Data Exchange (ETDEWEB)

    Yu Yunlong [Department of Plant Protection, Zhejiang University, Kaixuan Road 268, Hangzhou, Zhejiang 310029 (China)]. E-mail: ylyu@zju.edu.cn; Wu Xiaomao [Department of Plant Protection, College of Agriculture, Guizhou University, Guiyang 550025 (China); Li Shaonan [Department of Plant Protection, Zhejiang University, Kaixuan Road 268, Hangzhou, Zhejiang 310029 (China); Fang Hua [Department of Plant Protection, Zhejiang University, Kaixuan Road 268, Hangzhou, Zhejiang 310029 (China); Zhan Haiyan [Department of Plant Protection, Zhejiang University, Kaixuan Road 268, Hangzhou, Zhejiang 310029 (China); Yu Jingquan [Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China)

    2006-06-15

    A study was conducted to determine the adsorption/desorption of butachlor, myclobutanil and chlorpyrifos on five soils using a batch equilibration technique and to study the relationship between bioavailability to Allolobophora caliginosa and the adsorption/desorption of these three pesticides. The results showed that the adsorption/desorption processes of the tested compounds were mainly controlled by soil organic matter content (OM) and octanol/water-partitioning coefficient (K {sub ow}), and that the bioavailability of the pesticides was dependent on characteristics of pesticides, properties of soils, and uptake routes of earthworms. Bioconcentration of butachlor and myclobutanil was negatively correlated with Freundlich adsorption constant K {sub af} and K {sub df}. However, only a slightly positive correlation between bioconcentration and K {sub af} and K {sub df} was observed for chlorpyrifos due to its high affinity onto soil. - Bioavailability of pesticides in soil to earthworm is governed by adsorption characteristics.

  8. Copper bioavailability and toxicity to Mytilus galloprovincialis in Shelter Island Yacht Basin, San Diego, CA.

    Science.gov (United States)

    Bosse, Casey; Rosen, Gunther; Colvin, Marienne; Earley, Patrick; Santore, Robert; Rivera-Duarte, Ignacio

    2014-08-15

    The bioavailability and toxicity of copper (Cu) in Shelter Island Yacht Basin (SIYB), San Diego, CA, USA, was assessed with simultaneous toxicological, chemical, and modeling approaches. Toxicological measurements included laboratory toxicity testing with Mytilus galloprovincialis (Mediterranean mussel) embryos added to both site water (ambient) and site water spiked with multiple Cu concentrations. Chemical assessment of ambient samples included total and dissolved Cu concentrations, and Cu complexation capacity measurements. Modeling was based on chemical speciation and predictions of bioavailability and toxicity using a marine Biotic Ligand Model (BLM). Cumulatively, these methods assessed the natural buffering capacity of Cu in SIYB during singular wet and dry season sampling events. Overall, the three approaches suggested negligible bioavailability, and isolated observed or predicted toxicity, despite an observed gradient of increasing Cu concentration, both horizontally and vertically within the water body, exceeding current water quality criteria for saltwater.

  9. Enhanced bioavailability and bioefficacy of an amorphous solid dispersion of curcumin.

    Science.gov (United States)

    Chuah, Ai Mey; Jacob, Bindya; Jie, Zhang; Ramesh, Subbarayan; Mandal, Shibajee; Puthan, Jithesh K; Deshpande, Parag; Vaidyanathan, Vadakkanchery V; Gelling, Richard W; Patel, Gaurav; Das, Tapas; Shreeram, Sathyavageeswaran

    2014-08-01

    Curcumin has been shown to have a wide variety of biological activities for various human diseases including inflammation, diabetes and cancer. However, the poor oral bioavailability of curcumin poses a significant pharmacological barrier to its use therapeutically and/or as a functional food. Here we report the evaluation of the bioavailability and bio-efficacy of curcumin as an amorphous solid dispersion (ASD) in a matrix consisting of hydroxypropyl methyl cellulose (HPMC), lecithin and isomalt using hot melt extrusion for application in food products. Oral pharmacokinetic studies in rats showed that ASD curcumin was ∼13-fold more bioavailable compared to unformulated curcumin. Evaluation of the anti-inflammatory activity of ASD curcumin in vivo demonstrated enhanced bio-efficacy compared to unformulated curcumin at 10-fold lower dose. Thus ASD curcumin provides a more potent and efficacious formulation of curcumin which may also help in masking the colour, taste and smell which currently limit its application as a functional food ingredient.

  10. Multivitamin and multimineral dietary supplements: definitions, characterization, bioavailability, and drug interactions.

    Science.gov (United States)

    Yetley, Elizabeth A

    2007-01-01

    Although multivitamins, multiminerals, and similar terms (eg, multis or multiples) are commonly used, they have no standard scientific, regulatory, or marketplace definitions. Thus, multivitamins-multiminerals refers to products with widely varied compositions and characteristics. Multivitamin-multimineral composition databases use label values as surrogates for analyzed values. However, actual vitamin and mineral amounts often deviate from label values. Vitamin and mineral bioavailability for dietary supplements also lacks a standard scientific and regulatory definition and validated in vitro and animal models that accurately reflect human bioavailabilities. Systematic information on the bioavailability and bioequivalence of vitamins and minerals in marketed products and on potential drug interactions is scarce. Because of limited information on product characteristics, our ability to directly compare results across studies, estimate changes in usage patterns or intakes over time, and generalize from published results to marketed products is problematic.

  11. Relating Bioavailability Parameters to the Sorbent Characteristics of PAH Polluted Soils

    DEFF Research Database (Denmark)

    Bartolome, N.; Hilber, I.; Schulin, R.

    2015-01-01

    Regulation of Hydrophobic Organic Contaminants (HOC) such as polycyclic aromatic hydrocarbons (PAHs) in soil is still based on total concentrations. However, many studies have demonstrated that not all of a pollutant’s content in soil is equally available to organisms (Reichenberg & Mayer 2006...... to several sorbent characteristics including organic and black carbon content. The results will provide a better understanding of bioavailability of PAHs in soils. Moreover, the outcomes will be discussed regarding to the potential application of chemical proxies in soil pollution risk assessment......). Over the last decade, intensive effort has been made to incorporate bioavailability into risk assessment (Cachada et al. 2014). Here, we compare total concentrations of PAH with two bioavailability parameters in 30 different soil samples from the archive of the standardized National and Zurich Cantonal...

  12. Bioavailability and mobility of organic contaminants in soil: new three-step ecotoxicological evaluation.

    Science.gov (United States)

    Prokop, Zbyněk; Nečasová, Anežka; Klánová, Jana; Čupr, Pavel

    2016-03-01

    A novel approach was developed for rapid assessment of bioavailability and potential mobility of contaminants in soil. The response of the same test organism to the organic extract, water extract and solid phase of soil was recorded and compared. This approach was designed to give an initial estimate of the total organic toxicity (response to organic extractable fraction), as well as the mobile (response to water extract) and bioavailable fraction (response to solid phase) of soil samples. Eighteen soil samples with different levels of pollution and content of organic carbon were selected to validate the novel three-step ecotoxicological evaluation approach. All samples were chemically analysed for priority contaminants, including aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH) and dichlordiphenyltrichloroethane (DDT). The ecotoxicological evaluation involved determination of toxicity of the organic, mobile and bioavailable fractions of soil to the test organism, bacterium Bacillus cereus. We found a good correlation between the chemical analysis and the toxicity of organic extract. The low toxicity of water extracts indicated low water solubility, and thus, low potential mobility of toxic contaminants present in the soil samples. The toxicity of the bioavailable fraction was significantly greater than the toxicity of water-soluble (mobile) fraction of the contaminants as deduced from comparing untreated samples and water extracts. The bioavailability of the contaminants decreased with increasing concentrations of organic carbon in evaluated soil samples. In conclusion, the three-step ecotoxicological evaluation utilised in this study can give a quick insight into soil contamination in context with bioavailability and mobility of the contaminants present. This information can be useful for hazard identification and risk assessment of soil-associated contaminants. Graphical Abstract New three-step ecotoxicological

  13. Enhancement of intestinal permeability utilizing solid lipid nanoparticles increases γ-tocotrienol oral bioavailability.

    Science.gov (United States)

    Abuasal, Bilal S; Lucas, Courtney; Peyton, Breanne; Alayoubi, Alaadin; Nazzal, Sami; Sylvester, Paul W; Kaddoumi, Amal

    2012-05-01

    γ-Tocotrienol (γ-T3), a member of the vitamin E family, has been reported to possess an anticancer activity. γ-T3 is a lipophilic compound with low oral bioavailability. Previous studies showed that γ-T3 has low intestinal permeability. Thus, we have hypothesized that enhancing γ-T3 intestinal permeability will increase its oral bioavailability. Solid lipid nanoparticles (SLN) were tested as a model formulation to enhance γ-T3 permeability and bioavailability. γ-T3 intestinal permeability was compared using in situ rat intestinal perfusion, followed by in vivo relative oral bioavailability studies. In addition, in vitro cellular uptake of γ-T3 from SLN was compared to mixed micelles (MM) in a time and concentration-dependent studies. To elucidate the uptake mechanism(s) of γ-T3 from SLN and MM the contribution of NPC1L1 carrier-mediated uptake, endocytosis and passive permeability were investigated. In situ studies demonstrated SLN has tenfold higher permeability than MM. Subsequent in vivo studies showed γ-T3 relative oral bioavailability from SLN is threefold higher. Consistent with in situ results, in vitro concentration dependent studies revealed γ-T3 uptake from SLN was twofold higher than MM. In vitro mechanistic characterization showed that while endocytosis contributes to γ-T3 uptake from both formulations, the reduced contribution of NPC1L1 to the transport of γ-T3, and passive diffusion enhancement of γ-T3 are primary explanations for its enhanced uptake from SLN. In conclusion, SLN successfully enhanced γ-T3 oral bioavailability subsequent to enhanced passive permeability.

  14. Dissolved organic matter composition and bioavailability reflect ecosystem productivity in the Western Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Y. Shen

    2012-12-01

    Full Text Available Dissolved organic carbon (DOC and total dissolved amino acids (TDAA were measured in high (Chukchi Sea and low (Beaufort Sea productivity regions of the western Arctic Ocean to investigate the composition and bioavailability of dissolved organic matter (DOM. Concentrations and DOC-normalized yields of TDAA in Chukchi surface waters were relatively high, indicating an accumulation of bioavailable DOM. High concentrations and yields of TDAA were also observed in the upper halocline of slope and basin waters, indicating off-shelf transport of bioavailable DOM from the Chukchi Sea. In contrast, concentrations and yields of TDAA in Beaufort surface waters were relatively low, indicting DOM was of limited bioavailability. Concentrations and yields of TDAA in the upper halocline of slope and basin waters were also low, suggesting the Beaufort is not a major source of bioavailable DOM to slope and basin waters. In shelf waters of both systems, elevated concentrations and yields of TDAA were often observed in waters with higher chlorophyll concentrations and productivity. Surface concentrations of DOC were similar (p > 0.05 in the two systems despite the contrasting productivity, but concentrations and yields of TDAA were significantly higher (p < 0.0001 in the Chukchi than in the Beaufort. Unlike bulk DOC, TDAA concentrations and yields reflect ecosystem productivity in the western Arctic. The occurrence of elevated bioavailable DOM concentrations in the Chukchi Sea implies an uncoupling between the biological production and utilization of DOM and has important implications for sustaining heterotrophic microbial growth and diversity in oligotrophic waters of the central Arctic basins.

  15. Dissolved organic matter composition and bioavailability reflect ecosystem productivity in the Western Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Y. Shen

    2012-07-01

    Full Text Available Dissolved organic carbon (DOC and total dissolved amino acids (TDAA were measured in high (Chukchi Sea and low (Beaufort Sea productivity regions of the Western Arctic Ocean to investigate the composition and bioavailability of dissolved organic matter (DOM. Concentrations and DOC-normalized yields of TDAA in Chukchi surface waters were relatively high, indicating an accumulation of bioavailable DOM. High yields of TDAA were also observed in the upper halocline of slope and basin waters, indicating off-shelf transport of bioavailable DOM from the Chukchi Sea. In contrast, concentrations and yields of TDAA in Beaufort surface waters were relatively low, indicting DOM was of limited bioavailability. Yields of TDAA in the upper halocline of slope and basin waters were also low, suggesting the Beaufort is not a major source of bioavailable DOM to slope and basin waters. In shelf waters of both systems, elevated concentrations and yields of TDAA were often observed in waters with higher chlorophyll concentrations and productivity. Surface concentrations of DOC were similar (p > 0.05 in the two systems despite the contrasting productivity, but concentrations and yields of TDAA were significantly higher (p < 0.0001 in the Chukchi than in the Beaufort. Unlike bulk DOC, TDAA concentrations and yields reflect ecosystem productivity in the Western Arctic. The occurrence of elevated bioavailable DOM concentrations in the Chukchi implies an uncoupling between the biological production and utilization of DOM and has important implications for sustaining heterotrophic microbial growth and diversity in oligotrophic waters of the Central Arctic basins.

  16. Biofortification and bioavailability of rice grain zinc as affected by different forms of foliar zinc fertilization.

    Directory of Open Access Journals (Sweden)

    Yanyan Wei

    Full Text Available BACKGROUND: Zinc (Zn biofortification through foliar Zn application is an attractive strategy to reduce human Zn deficiency. However, little is known about the biofortification efficiency and bioavailability of rice grain from different forms of foliar Zn fertilizers. METHODOLOGY/PRINCIPAL FINDINGS: Four different Zn forms were applied as a foliar treatment among three rice cultivars under field trial. Zinc bioavailability was assessed by in vitro digestion/Caco-2 cell model. Foliar Zn fertilization was an effective agronomic practice to promote grain Zn concentration and Zn bioavailability among three rice cultivars, especially, in case of Zn-amino acid and ZnSO(4. On average, Zn-amino acid and ZnSO(4 increased Zn concentration in polished rice up to 24.04% and 22.47%, respectively. On average, Zn-amino acid and ZnSO(4 increased Zn bioavailability in polished rice up to 68.37% and 64.43%, respectively. The effectiveness of foliar applied Zn-amino acid and ZnSO(4 were higher than Zn-EDTA and Zn-Citrate on improvement of Zn concentration, and reduction of phytic acid, as a results higher accumulation of bioavailable Zn in polished rice. Moreover, foliar Zn application could maintain grain yield, the protein and minerals (Fe and Ca quality of the polished rice. CONCLUSIONS: Foliar application of Zn in rice offers a practical and useful approach to improve bioavailable Zn in polished rice. According to current study, Zn-amino acid and ZnSO(4 are recommended as excellent foliar Zn forms to ongoing agronomic biofortification.

  17. Bioavailability of Phosphorus in Two Cultivars of Pea for Broiler Chicks.

    Science.gov (United States)

    Woyengo, T A; Emiola, I A; Kim, I H; Nyachoti, C M

    2016-03-01

    The aim was to determine the relative bioavailability of phosphorus (P) in peas for 21-day old broiler chickens using slope-ratio assay. One hundred and sixty eight male Ross 308 broiler chicks were divided into 42 groups 4 balanced for body weight and fed 7 diets in a completely randomized design (6 groups/diet) from day 1 to 21 of age. The diets were a corn-soybean meal basal diet, and the corn-soybean meal basal diet to which monosodium phosphate, brown- or yellow-seeded pea was added at the expense of cornstarch to supply 0.5% or 1% total phosphorus. Monosodium phosphate was included as a reference, and hence the estimated bioavailability of P in pea cultivars was relative to that in the monosodium phosphate. Birds and feed were weighed weekly and on d 21 they were killed to obtain tibia. The brown-seeded pea contained 23.4% crude protein, 0.47% P, whereas the yellow-seeded pea contained 24.3% crude protein and 0.38% P. Increasing dietary P supply improved (ppeas obtained using final body weight, average daily gain, tibia ash, and bone mineral density were 31.5% and 36.2%, 35.6% and 37.3%, 23.0% and 5.60%, and 40.3% and 30.3%, respectively. The estimated relative bioavailability of p values for brown- and yellow-seeded peas did not differ within each of the response criteria measured in this study. In conclusion, the relative bioavailability of P in pea did not differ depending on the cultivar (brown- vs yellow-seed). However, the relative bioavailability of P in pea may vary depending on the response criterion used to measure the bioavailability.

  18. Simultaneous detection of bioavailable arsenic and cadmium in contaminated soils using dual-sensing bioreporters.

    Science.gov (United States)

    Yoon, Youngdae; Kim, Sunghoon; Chae, Yooeun; Kim, Shin Woong; Kang, Yerin; An, Gyeonghyeon; Jeong, Seung-Woo; An, Youn-Joo

    2016-04-01

    Whole-cell bioreporters (WCBs) have attracted increasing attention during the last few decades because they allow fast determination of bioavailable heavy metals in contaminated sites. Various WCBs to monitor specific heavy metals such as arsenic and cadmium in diverse environmental systems are available. However, currently, no study on simultaneous analysis of arsenic and cadmium has been reported, even though soils are contaminated by diverse heavy metals and metalloids. We demonstrated herein the development of dual-sensing WCBs to simultaneously quantify bioavailable arsenic and cadmium in contaminated sites by employing the promoter regions of the ars and znt operons as separate metal-sensing domains, and egfp and mcherry as reporter genes. The dual-sensing WCBs were generated by inserting two sets of genes into E. coli DH5α. The capability of WCBs was successfully proved to simultaneously quantify bioavailable arsenic and cadmium in amended Landwirtschaftliche Untersuchungs und Forschungsanstalt (LUFA) soils, and then, it was applied to contaminated field soils collected from a smelter area in Korea. As a result, it was noticed that the bioavailable portion of cadmium was higher than that of arsenic while the absolute amount of bioavailable arsenic and cadmium level was opposite. Since both cadmium and arsenic were assessed from the same E. coli cells, the data obtained by using dual-sensing WCBs would be more efficient and convenient than that from comparative WCB assay. In spite of advantageous aspects, to our knowledge, this is the first report on a dual-sensing WCB for rapid and concurrent quantification of bioavailable arsenic and cadmium in contaminated soils.

  19. Induced metal redistribution and bioavailability enhancement in contaminated river sediment during in situ biogeochemical remediation.

    Science.gov (United States)

    Liu, Tongzhou; Zhang, Zhen; Mao, Yanqing; Yan, Dickson Y S

    2016-04-01

    In situ sediment remediation using Ca(NO3)2 or CaO2 for odor mitigation and acid volatile sulfide (AVS) and organic pollutant (such as TPH and PAHs) removal was reported in many studies and fieldwork. Yet, the associated effects on metal mobilization and potential distortion in bioavailability were not well documented. In this study, contaminated river sediment was treated by Ca(NO3)2 and CaO2 in bench studies. Through the investigation of AVS removal, organic matter removal, the changes in sediment oxidation-reduction potential (ORP), microbial activity, and other indigenous parameters, the effects on metal bioavailability, bioaccessibility, and fraction redistribution in sediment were evaluated. The major mechanisms for sediment treated by Ca(NO3)2 and CaO2 are biostimulation with indigenous denitrifying bacteria and chemical oxidation, respectively. After applying Ca(NO3)2 and CaO2, the decreases of metal concentrations in the treated sediment were insignificant within a 35-day incubation period. However, the [SEMtot-AVS]/f OC increased near to the effective boundary of toxicity (100 μmol g(-1) organic carbon (OC)), indicating that both bioavailability and bioaccessibility of metals (Cu, Zn, and Ni) to benthic organisms are enhanced after remediation. Metals were found redistributed from relatively stable fractions (oxidizable and residual fractions) to weakly bound fractions (exchangeable and reducible fractions), and the results are in line with the enhanced metal bioavailability. Compared with Ca(NO3)2, CaO2 led to higher enhancement in metal bioavailability and bioaccessibility, and more significant metal redistribution, probably due to its stronger chemical reactive capacity to AVS and sediment organic matter. The reactions in CaO2-treated sediment would probably shift from physicochemical to biochemical heterotrophic oxidation for sediment organic matter degradation. Therefore, further investigation on the long-term metal redistribution and associated

  20. Bioavailability of Cd, Zn and Hg in Soil to Nine Recombinant Luminescent Metal Sensor Bacteria

    Directory of Open Access Journals (Sweden)

    Olesja Bondarenko

    2008-11-01

    Full Text Available A set of nine recombinant heavy metal-specific luminescent bacterial sensors belonging to Gram-negative (Escherichia and Pseudomonas and Gram-positive (Staphylococcus and Bacillus genera and containing various types of recombinant metalresponse genetic elements was characterized for heavy metal bioavailability studies. All nine strains were induced by Hg and Cd and five strains also by Zn. As a lowest limit, the sensors were detecting 0.03 μg·L-1 of Hg, 2 μg·L-1 of Cd and 400 μg·L-1 of Zn. Limit of determination of the sensors depended mostly on metal-response element, whereas the toxicity of those metals towards the sensor bacteria was mostly dependent on the type of the host bacterium, with Gram-positive strains being more sensitive than Gram-negative ones. The set of sensors was used to evaluate bioavailability of Hg, Cd and Zn in spiked soils. The bioavailable fraction of Cd and Zn in soil suspension assay (2.6 – 5.1% and 0.32 – 0.61%, of the total Cd and Zn, respectively was almost comparable for all the sensors, whereas the bioavailability of Hg was about 10-fold higher for Gram-negative sensor cells (30.5% of total Hg, compared to Gram-positive ones (3.2% of the total Hg. For Zn, the bioavailable fraction in soil-water suspensions and respective extracts was comparable (0.37 versus 0.33% of the total Zn. However, in the case of Cd, for all the sensors used and for Hg concerning only Gram-negative sensor strains, the bioavailable fraction in soilwater suspensions exceeded the water-extracted fraction about 14-fold, indicating that upon direct contact, an additional fraction of Cd and Hg was mobilized by those sensor bacteria. Thus, for robust bioavailability studies of heavy metals in soils any type of genetic metal-response elements could be used for the construction of the sensor strains. However, Gram-positive and Gram-negative senor strains should be used in

  1. Comparison of partial extraction reagents for assessing potential bioavailability of heavy metals in sediments.

    Science.gov (United States)

    Brady, James P; Kinaev, Irina; Goonetilleke, Ashantha; Ayoko, Godwin A

    2016-05-15

    Assessment of heavy metal bioavailability in sediments is complex because of the number of partial extraction methods available for the assessment and the general lack of certified reference materials. This study evaluates five different extraction methodologies to ascertain the relative strengths and weaknesses of each method. The results are then compared to previously published work to ascertain the most effective partial extraction technique, which was established to dilute (0.75-1M) nitric acid solutions. These results imply that single reagent; weak acid extractions provide a better assessment of potentially bioavailable metals than the chelating agents used in sequential extraction methods.

  2. Relative bioavailability in man of noscapine administered in lozenges and mixture

    DEFF Research Database (Denmark)

    Jensen, L.N.; Christrup, Lona Louring; Jacobsen, L.

    1992-01-01

    The bioavailability of noscapine base administered in lozenges in a dose of 100 mg to twelve healthy volunteers, in a study using an open balanced cross-over design, was compared with that of 100 mg of noscapine hydrochloride given perorally as a mixture. The bioavailability of noscapine after...... administration in lozenges was significantly higher than that after administration of the drug as a mixture. It is concluded that the lozenges containing noscapine base may be a valuable alternative to the conventional noscapine hydrochloride mixture....

  3. Pharmaceutical particle technologies: An approach to improve drug solubility, dissolution and bioavailability

    Directory of Open Access Journals (Sweden)

    Prakash Khadka

    2014-12-01

    Full Text Available Pharmaceutical particle technology is employed to improve poor aqueous solubility of drug compounds that limits in vivo bioavailability owing to their low dissolution rate in the gastrointestinal fluids following oral administration. The particle technology involves several approaches from the conventional size reduction processes to the newer, novel particle technologies that modify the solubility properties of the drugs and produce solid, powdered form of the drugs that are readily soluble in water and can be easily formulated into various dosage forms. This review highlights the solid particle technologies available for improving solubility, dissolution and bioavailability of drugs with poor aqueous solubility.

  4. Bioavailability of omega-3 long-chain polyunsaturated fatty acids from foods

    DEFF Research Database (Denmark)

    Mu, Huiling

    2008-01-01

    Increasing recognition of the importance of the omega-3 long chain polyunsaturated fatty acids (LCPUFA) has caused greater attention about dietary intake of these fatty acids. Fatty fish is the major dietary source of these fatty acids. Because of the low intake of fish at many places, foods...... enriched with omega-3 LCPUFA can be good alternatives to improve the intake of these fatty acids. Effects of lipid structures and food matrices on bioavailability of omega-3 LCPUFA have been investigated. Short term studies showed that both lipid structure and food matrix affect the bioavailability...

  5. Application of a mer-lux biosensor for estimating bioavailable mercury in soil

    DEFF Research Database (Denmark)

    Rasmussen, Lasse Dam; Sørensen, Søren Johannes; Turner, Ralph R.

    2000-01-01

    responses. The utility of the mer-lux biosensor assay was tested by relating measurements of bioavailable and total mercury to the response of the soil microbial community to mercury exposure. Two different soil types (an agricultural and a beech forest soil) were spiked with 2.5 µg Hg(II) g-1 in microcosms...... in resistance or diversity. This study showed that the bioassay using the mer-lux biosensor is a useful and sensitive tool for estimation of bioavailable mercury in soil....

  6. Carotenoids: Actual knowledge on food sources, intakes, stability and bioavailability and their protective role in humans

    DEFF Research Database (Denmark)

    Maiani, Giuseppe; Castón, María Jesús Periago; Catasta, Giovina

    2009-01-01

    Carotenoids are one of the major food micronutrients in human diets and the overall objective of this review is to re-examine the role of carotenoids in human nutrition. We have emphasized the attention on the following carotenoids present in food and human tissues: -carotene, -cryptoxanthin......, -carotene, lycopene, lutein and zeaxanthin; we have reported the major food sources and dietary intake of these compounds. We have tried to summarize positive and negative effects of food processing, storage, cooking on carotenoid content and carotenoid bioavailability. In particular, we have evidenced...... the possibility to improve carotenoids bioavailability in accordance with changes and variations of technology procedures....

  7. Whole-Cell Fluorescent Biosensors for Bioavailability and Biodegradation of Polychlorinated Biphenyls

    Directory of Open Access Journals (Sweden)

    David Ryan

    2010-02-01

    Full Text Available Whole-cell microbial biosensors are one of the newest molecular tools used in environmental monitoring. Such biosensors are constructed through fusing a reporter gene such as lux, gfp or lacZ,to a responsive promoter. There have been many reports of the applications of biosensors, particularly their use in assaying pollutant toxicity and bioavailability. This paper reviews the basic concepts behind the construction of whole-cell microbial biosensors for pollutant monitoring, and describes the applications of two such biosensors for detecting the bioavailability and biodegradation of Polychlorinated Biphenyls (PCBs.

  8. Improving bioavailability and anthelmintic activity of albendazole by preparing albendazole-cyclodextrin complexes

    Directory of Open Access Journals (Sweden)

    García-Rodriguez J.J.

    2001-06-01

    Full Text Available The bioavailability and anthelmintic activity of albendazole-cyclodextrin complexes (ABZ-CDC compared to albendazole suspensions in carboxymethylcellulose (ABZ-CMC was assessed in a mouse model for Trichinella infections. Swiss CD-1 mice experimentally infected with T. spiralis were treated with both formulations against enteral (adult worms and parenteral (migrating and encysted larvae. Oral bioavailability was assessed in age matched mice treated with 50 mg/kg of both formulations. The anthelmintic effects and plasma concentration of the active metabolite albendazole-sulphoxide (ABZSO enantiomer (– were significantly increased following administration of ABZ-CDC in relation to ABZ-CMC.

  9. In Vitro And In Vivo Approaches For The Measurement Of Oral Bioavailability Of Lead (Pb) In Contaminated Soils: A Review

    Science.gov (United States)

    We reviewed the published evidence of lead (Pb) contamination of urban soils, soil Pb risk to children through hand-to-mouth activity, reduction of soil Pb bioavailability due to soil amendments, and methods to assess bioaccessibility which correlate with bioavailability of soil ...

  10. Utilizing Polymer-Coated Vials to Illustrate the Fugacity and Bioavailability of Chlorinated Pesticide Residues in Contaminated Soils

    Science.gov (United States)

    Andrade, Natasha A.; McConnell, Laura L.; Torrents, Alba; Hapeman, Cathleen J.

    2013-01-01

    Fugacity and bioavailability can be used to facilitate students' understanding of potential environmental risks associated with toxic chemicals and, therefore, should be incorporated in environmental chemistry and science laboratories. Although the concept of concentration is easy to grasp, fugacity and bioavailability can be challenging…

  11. Extraction of carotenoids from feces enabling the bioavailability of ß-carotene to be studied in Indonesian children

    NARCIS (Netherlands)

    Lieshout, van M.; West, C.E.; Bovenkamp, van de P.; Wang, Y.; Sun, Y.; Breemen, van R.B.; Permaesih, D.; Muhilal,; Verhoeven, M.A.; Creemers, A.F.L.; Lugtenburg, J.

    2003-01-01

    Previously, we have presented a method for quantifying beta-carotene bioavailability based on analysis in serum, following administration of C-13-labeled beta-carotene. Because stool samples can be collected noninvasively, we have now extended the method to measure the bioavailability based on measu

  12. EARLY INDICATORS OF NITRATE STRESS; EFFECTS TO ECOSYSTEMS OF CHRONIC EXPOSURE TO LOW DOSES OF BIOAVAILABLE NITROGEN

    Science.gov (United States)

    Throughout the eastern United States, from the Front Range of the Rocky Mountains to the Atlantic Ocean, bioavailable nitrogen has been falling in the rain since the industrial revolution. Bioavailable nitrogen is a limiting nutrient throughout this region. While long-term rese...

  13. Does vitamin C enhance nitric oxide bioavailability in a tetrahydrobiopterin-dependent manner? In vitro, in vivo and clinical studies.

    Science.gov (United States)

    Mortensen, Alan; Lykkesfeldt, Jens

    2014-01-30

    Ascorbate (Asc) has been shown to increase nitric oxide (NO) bioavailability and thereby improve endothelial function in patients showing signs of endothelial dysfunction. Tetrahydrobiopterin (BH₄) is a co-factor of endothelial nitric oxide synthase (eNOS) which may easily become oxidized to the inactive form dihydrobiopterin (BH₂). Asc may increase NO bioavailability by a number of mechanisms involving BH₄ and eNOS. Asc increases BH₄ bioavailability by either reducing oxidized BH₄ or preventing BH₄ from becoming oxidized in the first place. Asc could also increase NO bioavailability in a BH₄-independent manner by increasing eNOS activity by changing its phosphorylation and S-nitrosylation status or by upregulating eNOS expression. In this review, we discuss the putative mechanisms by which Asc may increase NO bioavailability through its interactions with BH₄ and eNOS.

  14. Bioavailability-based toxicity endpoints of bifenthrin for Hyalella azteca and Chironomus dilutus.

    Science.gov (United States)

    Harwood, Amanda D; Landrum, Peter F; Lydy, Michael J

    2013-01-01

    Recent studies have determined that techniques, such as solid phase microextraction (SPME) fibers and Tenax beads, can predict bioaccumulation and potentially could predict toxicity for several compounds and species. Toxicity of bifenthrin was determined using two standard sediment toxicity tests with the benthic species Hyalella azteca and Chironomus dilutus in three reference sediments with different characteristics. The objectives of the current study were to establish bioavailability-based median lethal concentrations (LC50) and median effect concentrations (EC50) of the pyrethroid insecticide bifenthrin, compare their ability to assess toxicity to the use of whole sediment concentrations, as well as to make comparisons of the concentrations derived using each method in order to make assessments of accuracy and extrapolation potential. Four metrics were compared including SPME fiber concentration, pore water concentration derived using SPMEs, 6 h Tenax extractable concentration, and 24 h Tenax extractable concentration. The variation among the LC50s and EC50s in each sediment derived using bioavailability-based methods was comparable to variation among organic carbon normalized sediment concentrations, but improved over whole sediment concentrations. There was a significant linear relationship between SPME or Tenax and organic carbon normalized sediment concentrations. Additionally, there was a significant relationship between the SPME and Tenax concentrations across sediments. The significant linear relationship between SPME and Tenax concentrations further demonstrates that these bioavailability-based endpoints are interrelated. This study derived bioavailability-based benchmarks that may prove to be more accurate than sediment-based ones in predicting toxicity across sediment types.

  15. Selenium speciation and bioavailability in Dutch agricultural soils: the role of soil organic matter

    NARCIS (Netherlands)

    Supriatin, Supriatin

    2016-01-01

    Selenium (Se) is an essential micronutrient for animals and humans. In the food chain, the intake of Se by animals and humans depends largely on Se content in plants, whereas the major source of Se in plants lies in the soil. Therefore, understanding Se bioavailability in soils for plant uptake and

  16. Bioavailibility of selenium from fish, yeast and selenate: a comparative study in humans using stable isotopes

    NARCIS (Netherlands)

    Fox, T.E.; Heuvel, van den E.G.H.M.; Atherton, C.A.; Luten, J.B.; Hoek-van Nieuwenhuizen, van M.; Kotterman, M.J.J.

    2004-01-01

    Objective: To measure the bioavailability of selenium from cooked and raw fish in humans by estimating and comparing apparent absorption and retention of selenium in biosynthetically labelled fish with labelled selenate and biosynthetically labelled selenium in brewers yeast. Design: The interventio

  17. Preparation and evaluation of kaempferol-phospholipid complex for pharmacokinetics and bioavailability in SD rats.

    Science.gov (United States)

    Zhang, Kexia; Gu, Liqiang; Chen, Jinpeng; Zhang, Yuanyuan; Jiang, Yu; Zhao, Longshan; Bi, Kaishun; Chen, Xiaohui

    2015-10-10

    As one of the dietary flavonoids, kaempferol (KP) has been well known to show strong anti-oxidative effect along with other biological properties. However, the oral bioavailability of KP is relatively low due to its poor solubility. In this study, we intended to increase the solubility and bioavailability of KP by preparing kaempferol-phospholipid complex (KP-PC). The KP-PC's physicochemical properties were characterized in terms of infrared spectroscopy (IR), differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD), water/n-Octanol solubility and in vitro dissolution. KP-PC exhibited higher solubility and dissolution rate than KP, indicating a significant improvement in hydrophilicity. A UPLC-ESI-MS/MS method was developed and validated for the determination of KP in Sprague-Dawley (SD) rat plasma, so as to investigate the oral bioavailability of KP-PC versus KP. Results showed that Cmax and AUC(0-48 h) of KP from the complex (Cmax: 3.94 ± 0.83 μg/mL, AUC(0-48 h): 57.81 ± 9.43 mg/Lh) were higher than that of KP (Cmax: 1.43 ± 0.21 μg/mL, AUC(0-48 h): 13.65 ± 3.12 mg/Lh). This research indicated that phospholipid complex (PC) might be one of the suitable approachs to improve the oral bioavailability of KP and other poor-solubility flavonoids.

  18. Bioavailability assessments following biochar and activated carbon amendment in DDT-contaminated soil.

    Science.gov (United States)

    Denyes, Mackenzie J; Rutter, Allison; Zeeb, Barbara A

    2016-02-01

    The effects of 2.8% w/w granulated activated carbon (GAC) and two types of biochar (Burt's and BlueLeaf) on DDT bioavailability in soil (39 μg/g) were investigated using invertebrates (Eisenia fetida), plants (Cucurbita pepo spp. pepo) and a polyoxymethylene (POM) passive sampler method. Biochar significantly reduced DDT accumulation in E. fetida (49%) and showed no detrimental effects to invertebrate health. In contrast, addition of GAC caused significant toxic effects (invertebrate avoidance and decreased weight) and did not significantly reduce the accumulation of DDT into invertebrate tissue. None of the carbon amendments reduced plant uptake of DDT. Bioaccumulation of 4,4'DDT and 4,4'-DDE in plants (C. pepo spp. pepo) and invertebrates (E. fetida) was assessed using bioaccumulation factors (BAFs) and compared to predicted bioavailability using the freely-dissolved porewater obtained from a polyoxymethylene (POM) equilibrium biomimetic method. The bioavailable fraction predicted by the POM samplers correlated well with measured invertebrate uptake (DDT soil contamination levels and the inclusion of field data from a 2.5 μg/g DDT-contaminated site found that these plants exhibit a concentration threshold effect at [DDT](soil) > 10 μg/g. The results of these studies illustrate the importance of including plants in bioavailability studies as the use of carbon materials for in situ contaminant sorption moves from predominantly sediment to soil remediation technologies.

  19. Bioavailability pathways underlying zinc-induced avoidance behavior and reproduction toxicity in Lumbricus rubellus earthworms.

    NARCIS (Netherlands)

    Ma, W.C.; Bonten, L.T.C.

    2011-01-01

    We investigated possible bioavailability pathways underlying zinc-induced avoidance behavior and sublethal reproduction impairment in Lumbricus rubellus. Clay-loam (pH 7.3) and sandy soil (three pH values of 4.3–6.0) were amended with zinc sulfate at six soil concentrations of total Zn ranging from

  20. The effect of acidification on the bioavailability and electrochemical lability of zinc in seawater

    Science.gov (United States)

    Kim, Ja-Myung; Baars, Oliver; Morel, François M. M.

    2016-11-01

    A poorly studied but potentially important consequence of the CO2-induced acidification of the surface ocean is a possible change in the bioavailability of trace metals, which play a critical role in the productivity and population dynamics of marine ecosystems. We report laboratory and field experiments designed to compare quantitatively the effects of acidification on the bioavailability of Zn, a metal essential to the growth of phytoplankton and on the extent of its complexation by model and natural ligands. We observed a good correspondence between the effects of pH on the rate of Zn uptake by a model diatom and the chemical lability of Zn measured by anodic stripping voltammetry (ASV). In model laboratory systems, the chemical lability and the bioavailability of Zn could either increase or decrease at low pH depending on the mix of complexing ligands. In a sample of coastal surface water, we observed similar increases in the ASV-labile and bioavailable Zn concentrations upon acidification, a result contrary to previous observations. These results, which can likely be generalized to other bioactive trace metals, mutatis mutandis, demonstrate the intricacy of the effects of ocean acidification on the chemistry and the ecology of surface seawater. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

  1. Towards bioavailability-based soil criteria: Past, present and future perspectives

    Science.gov (United States)

    Bioavailability has been used as a key indicator in chemical risk assessment, yet it is a poorly quantified risk factor. Worldwide, the framework used to assess potentially contaminated sites is similar and the decisions are based on threshold contaminant concentration. The uncertainty in the defin...

  2. Predicting oral relative bioavailability of arsenic in soil from in vitro bioaccessibility

    Science.gov (United States)

    Several investigations have been conducted to develop in vitro bioaccessibility (IVBA) assays that reliably predict in vivo oral relative bioavailability (RBA) of arsenic (As). This study describes a meta-regression model relating soil As RBA and IVBA that is based upon data comb...

  3. On the bioavailability of trace metals in surface sediments: a combined geochemical and biological approach.

    Science.gov (United States)

    Roosa, Stéphanie; Prygiel, Emilie; Lesven, Ludovic; Wattiez, Ruddy; Gillan, David; Ferrari, Benoît J D; Criquet, Justine; Billon, Gabriel

    2016-06-01

    The bioavailability of metals was estimated in three river sediments (Sensée, Scarpe, and Deûle Rivers) impacted by different levels of Cu, Cd, Pb, and Zn (Northern France). For that, a combination of geochemistry and biological responses (bacteria and chironomids) was used. The results obtained illustrate the complexity of the notion of "bioavailability." Indeed, geochemical indexes suggested a low toxicity, even in surface sediments with high concentrations of total metals and a predicted severe effect levels for the organisms. This was also suggested by the abundance of total bacteria as determined by DAPI counts, with high bacterial cell numbers even in contaminated areas. However, a fraction of metals may be bioavailable as it was shown for chironomid larvae which were able to accumulate an important quantity of metals in surface sediments within just a few days.We concluded that (1) the best approach to estimate bioavailability in the selected sediments is a combination of geochemical and biological approaches and that (2) the sediments in the Deûle and Scarpe Rivers are highly contaminated and may impact bacterial populations but also benthic invertebrates.

  4. Bioavailability of folic acid from fortified pasteurised and UHT-treated milk in humans

    NARCIS (Netherlands)

    Jong, R.J. de; Verwei, M.; West, C.E.; Vliet, T. van; Siebelink, E.; Berg, H. van den; Castenmiller, J.J.M.

    2005-01-01

    Objective: The aim of this study was to investigate whether milk fortified with folic acid enhances the folate status of humans and whether the presence of folate-binding proteins (FBP) in pasteurised milk affects the bioavailability of folic acid from fortified milk. In untreated and pasteurised mi

  5. Bioavailability of tramadol hydrochloride after administration via different routes in rats.

    Science.gov (United States)

    Zhang, Hua; Zhao, Youyou; Wang, Xueqing; Zhang, Qiang

    2014-12-01

    Tramadol is a synthetic non-opiate analgesic drug and effective for many kinds of chronic and acute pain. This study compared the bioavailability of tramadol after different administration routes in rats (oral, buccal and nasal). A simple HPLC analytical approach was used to determine the concentration of tramadol in plasma. The pharmacokinetic behavior and bioavailability of tramadol after administration via different routes in rats were investigated. Nasal and buccal administration of tramadol resulted in a fast increase followed by a rapid decrease in the plasma tramadol concentration. The Cmax values following buccal and nasal administration were 6 times and 20 times higher than that of oral administration, respectively, (6827.85 ± 7970.87 ng/ml, 22191.84 ± 5364.86 ng/ml, vs 1127.03 ± 778.34 ng/ml). The relative bioavailabilities of the nasal- and buccal-administered drug when compared with the oral route were 504.8% and 183.4%, respectively, which is much higher than that of oral administration. Nasal and buccal administration increased the bioavailability of tramadol, which may allow for a reduction in the dose of tramadol and a subsequent decrease in both side effects and toxicity. Therefore, this approach provides an effective choice for the delivery of tramadol, an analgesic drug.

  6. Bioavailability of milk protein-derived bioactive peptides: a glycaemic management perspective.

    Science.gov (United States)

    Horner, Katy; Drummond, Elaine; Brennan, Lorraine

    2016-06-01

    Milk protein-derived peptides have been reported to have potential benefits for reducing the risk of type 2 diabetes. However, what the active components are and whether intact peptides exert this bioactivity has received little investigation in human subjects. Furthermore, potentially useful bioactive peptides can be limited by low bioavailability. Various peptides have been identified in the gastrointestinal tract and bloodstream after milk-protein ingestion, providing valuable insights into their potential bioavailability. However, these studies are currently limited and the structure and sequence of milk peptides exerting bioactivity for glycaemic management has received little investigation in human subjects. The present article reviews the bioavailability of milk protein-derived peptides in human studies to date, and examines the evidence on milk proteins and glycaemic management, including potential mechanisms of action. Areas in need of advancement are identified. Only by establishing the bioavailability of milk protein-derived peptides, the active components and the mechanistic pathways involved can the benefits of milk proteins for the prevention or management of type 2 diabetes be fully realised in future.

  7. Lecithin-Based Nano-emulsification Improves the Bioavailability of Conjugated Linoleic Acid.

    Science.gov (United States)

    Heo, Wan; Kim, Jun Ho; Pan, Jeong Hoon; Kim, Young Jun

    2016-02-17

    In this study, we investigated the effects of lecithin-based nano-emulsification on the heat stability and bioavailability of conjugated linoleic acid (CLA) in different free fatty acid (FFA) and triglyceride (TG) forms. CLA nano-emulsion in TG form exhibited a small droplet size (70-120 nm) compared to CLA nano-emulsion in FFA form (230-260 nm). Nano-emulsification protected CLA isomers in TG form, but not in free form, against thermal decomposition during the heat treatment. The in vitro bioavailability test using monolayers of Caco-2 human intestinal cells showed that nano-emulsification increased the cellular uptake of CLA in both FFA and TG forms. More importantly, a rat feeding study showed that CLA content in small intestinal tissues or plasma was higher when CLA was emulsified, indicating an enhanced oral bioavailability of CLA by nano-emulsification. These results provide important information for development of nano-emulsion-based delivery systems that improve thermal stability and bioavailability of CLA.

  8. Improving zinc bioavailability in transition from flooded to aerobic rice. A review

    NARCIS (Netherlands)

    Gao, X.; Hoffland, E.; Stomph, T.J.; Grant, C.A.; Zou, C.; Zhang, F.

    2012-01-01

    Zinc (Zn) deficiency is a widely occurring constraint for rice production and for human nutrition. Scarcity of water is leading to a shift from flooded to aerobic rice production, which can have an impact on Zn deficiency in rice. Zinc bioavailability is a function of both soil and plant factors tha

  9. Comparison of trace metal bioavailabilities in European coastal waters using mussels from Mytilus edulis

    NARCIS (Netherlands)

    Przytarska, J.E.; Sokolowski, A.; Wolowicz, M.; Hummel, H.; Jansen, J.M.

    2010-01-01

    Mussels from Mytilus edulis complex were used as biomonitors of the trace metals Fe, Mn, Pb, Zn, and Cu at 17 sampling sites to assess the relative bioavailability of metals in coastal waters around the European continent. Because accumulated metal concentrations in a given area can differ temporall

  10. Exceptionally strong sorption of infochemicals to activated carbon reduces their bioavailability to fish

    NARCIS (Netherlands)

    Jonker, Michiel T O; van Mourik, Louise

    2014-01-01

    The addition of activated carbon (AC) to sediments is a relatively new approach to remediate contaminated sites. Activated carbon strongly sorbs hydrophobic organic contaminants, thereby reducing their bioavailability and uptake in organisms. Because of its high sorption capacity, AC might, however,

  11. Effect of yeast extract on speciation and bioavailability of nickel and cobalt in anaerobic bioreactors

    NARCIS (Netherlands)

    Gonzalez-Gil, G.; Jansen, S.; Zandvoort, M.H.; Leeuwen, van H.P.

    2003-01-01

    The speciation of metals plays an important role in their bioavailability. In the case of anaerobic reactors for the treatment of wastewaters, the ubiquitous presence of sulfide leads to extensive precipitation of metals like nickel and cobalt, which are essential for the metabolism of the anaerobic

  12. Speciation of Se and DOC in soil solution and their relation to Se bioavailability.

    NARCIS (Netherlands)

    Weng, L.P.; Vega, F.A.; Supriatin, S.; Bussink, W.; Riemsdijk, van W.H.

    2011-01-01

    A 0.01 M CaCl2 extraction is often used to asses the bioavailability of plant nutrients in soils. However, almost no correlation was found between selenium (Se) in the soil extraction and Se content in grass. The recently developed anion Donnan membrane technique was used to analyze chemical speciat

  13. Physiological responses to divergent selection for phytate phosphorus bioavailability in a randombred chicken population

    Science.gov (United States)

    An investigation was conducted to study insulin-like growth factor (IGF) I, IGFII, insulin, glucagon, recombinant human leptin, triidothyronine (T3) and thyroxine (T4) levels in a randombred chicken population divergently selected for phosphorus bioavailability (PBA). There were also differences in ...

  14. Iron and zinc bioavailabilities to pigs from red and white beans (Phaseolus vulgaris L.) are similar

    Science.gov (United States)

    Common beans contain relatively high concentrations of iron (Fe) and zinc (Zn) but are also high in polyphenols and phytates, factors that may inhibit Fe and Zn absorption. In vitro (Caco-2 cells) and in vivo (pigs) models were used to compare Fe and Zn bioavailabilities between red and white beans,...

  15. Bioavailability and pharmacokinetics of the cardioprotecting flavonoid 7-monohydroxyethylrutoside in mice.

    NARCIS (Netherlands)

    Hassan, MA Abou El; Kedde, MA; Zwiers, UT; Tourn, E; Haenen, GR; Vijgh, van der W.J.F.

    2003-01-01

    PURPOSE: The pharmacokinetics and bioavailability of monoHER, a promising protector against doxorubicin-induced cardiotoxicity, were determined after different routes of administration. METHODS: Mice were treated with 500 mg.kg(-1) monoHER intraperitoneally (i.p.), subcutaneously (s.c.) or intraveno

  16. [Application of bionic technology to speciation analysis and bioavailability assessment of nickel in transgenic soybean].

    Science.gov (United States)

    Chen, Li-Hui; Li, Shun-Xing; Mou, Yang; Zheng, Feng-Ying; Li, Yan-Cai; Wang, Hui; Zheng, Na-Yan; Xie, He-Fang

    2013-11-01

    The safety of transgenic food has been paid the most attention to by the public and scientists. Trace metal bioavailability could provide information for safety assessment of transgenic food. The critical functional digestion and absorption in the gastrointestinal tract were simulated by bionic gastrointestinal digestion, metabolism of gut microbiota, and bionic biomembrane adsorption with liposome and then used for the pretreatment of transgenic and general soybeans. Ni speciation in the chyme was defined as affinity-liposome and water soluble Ni. Nickel bioavailability was assessed by the content of affinity-liposome Ni. Water soluble Ni was the main species of nickel complex in the chyme. Nickel bioavailability was 4.1% for transgenic soybean and 3.3% for general soybean, which could be enhanced by gastrointestinal digestion and metabolism of gut microbiota. After transgene, nickel bioavailability was increased 24% but the content of affinity-liposome Ni was 122.3 ng x g(-1) for transgenic soybean, just as 36% as that of general soybean.

  17. Bioavailability of flavonoids and cinnamic acids and their effect on plasma homocysteine in humans

    NARCIS (Netherlands)

    Olthof, M.R.

    2001-01-01

    Dietary antioxidants might prevent oxidative damage to tissues and therefore protect against cardiovascular disease and cancer. Dietary phenols are strong antioxidants in vitro but their role in vivo is uncertain. Furthermore, there are only limited data on their bioavailability in humans. The aim o

  18. Bioavailability and effects of non-ionic organic pesticides in soil

    NARCIS (Netherlands)

    Ronday, R.

    1995-01-01

    In soil contamination studies the extent of contamination is usually described in terms of the content of the chemical on a dry soil mass basis. However, it has been found that a particular content of a chemical in soil exhibits divergent bio-availability, and thus toxicity, in different soils. Meas

  19. Bioavailability and bioaccessibility of polycyclic aromatic hydrocarbons from (post-pyrolytically treated) biochars

    DEFF Research Database (Denmark)

    Hilber, Isabel; Mayer, Philipp; Gouliarmou, Varvara

    2017-01-01

    Bioaccessibility data of PAHs from biochar produced under real world conditions is scarce and the influence of feedstock and various post-pyrolysis treatments common in agriculture, such as co-composting or lacto-fermentation to produce silage fodder, on their bioavailability and bioaccessibility...

  20. Bioavailability of lysine for kittens in overheated casein is underestimated by the rat growth assay method.

    Science.gov (United States)

    Larsen, J A; Fascetti, A J; Calvert, C C; Rogers, Q R

    2010-10-01

    Growth assays were performed to determine lysine bioavailability for kittens and rats in untreated and heated casein; these values were compared with estimates obtained with an in vitro method. Body weight, food intake, nitrogen and dry matter digestibility, and plasma lysine were determined during an 80-day growth trial using kittens (n = 16). Body weight and food intake were determined during a 21-day growth trial using weanling rats (n = 80). The growth data showed bioavailable lysine to be 102.4% and 100.2% (for untreated casein) and 66.1% and 51.7% (for heated casein) for kittens and rats, respectively. There was no relationship between plasma lysine and dietary lysine concentrations for kittens. There were no significant differences in nitrogen or dry matter digestibility among diets for kittens. The chemically reactive lysine content of untreated casein was 99.6%, and of heated casein was 67.1%. Heat treatment of casein resulted in significantly decreased lysine bioavailability as estimated by all methods. For untreated casein, both growth assays showed good agreement with the in vitro method for available lysine. For heated casein, the rat growth assay significantly underestimated bioavailable lysine as determined in kittens while the in vitro method closely approximated this value for the cat.

  1. Novel, potent, selective, and orally bioavailable human betaII-tryptase inhibitors.

    Science.gov (United States)

    Sperandio, David; Tai, Vincent W-F; Lohman, Julia; Hirschbein, Bernie; Mendonca, Rohan; Lee, Chang-Sun; Spencer, Jeffrey R; Janc, James; Nguyen, Margaret; Beltman, Jerlyn; Sprengeler, Paul; Scheerens, Heleen; Lin, Tong; Liu, Liang; Gadre, Ashwini; Kellogg, Alisha; Green, Michael J; McGrath, Mary E

    2006-08-01

    The synthesis of novel [1,2,4]oxadiazoles and their structure-activity relationship (SAR) for the inhibition of tryptase and related serine proteases is presented. Elaboration of the P'-side afforded potent, selective, and orally bioavailable tryptase inhibitors.

  2. Evidence for Bioavailability of Au Nanoparticles from Soil and Biodistribution within Earthworms (Eisenia fetida)

    Energy Technology Data Exchange (ETDEWEB)

    J Unrine; S Hunyadi; O Tsyusko; W Rao; A Shoults-Wilson; P Bertsch

    2011-12-31

    Because Au nanoparticles (NPs) are resistant to oxidative dissolution and are easily detected, they have been used as stable probes for the behavior of nanomaterials within biological systems. Previous studies provide somewhat limited evidence for bioavailability of Au NPs in food webs, because the spatial distribution within tissues and the speciation of Au was not determined. In this study, we provide multiple lines of evidence, including orthogonal microspectroscopic techniques, as well as evidence from biological responses, that Au NPs are bioavailable from soil to a model detritivore (Eisenia fetida). We also present limited evidence that Au NPs may cause adverse effects on earthworm reproduction. This is perhaps the first study to demonstrate that Au NPs can be taken up by detritivores from soil and distributed among tissues. We found that primary particle size (20 or 55 nm) did not consistently influence accumulated concentrations on a mass concentration basis; however, on a particle number basis the 20 nm particles were more bioavailable. Differences in bioavailability between the treatments may have been explained by aggregation behavior in pore water. The results suggest that nanoparticles present in soil from activities such as biosolids application have the potential to enter terrestrial food webs.

  3. Evaluation of Small Arms Range Soils for Metal Contamination and Lead Bioavailability

    Science.gov (United States)

    2009-11-03

    ENVIRONMENTAL SCIENCE & TECHNOLOGY 9...been sieved to  micrometer. Metal concentrations determined by ICP-MS. Metals in µg/g. TOC as %. CEC in meq/100 g. B 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL...studies of reduced bioavailability. VOL. , NO. xx, XXXX / ENVIRONMENTAL SCIENCE & TECHNOLOGY 9 C D 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL.

  4. Binary lipids-based nanostructured lipid carriers for improved oral bioavailability of silymarin.

    Science.gov (United States)

    Shangguan, Mingzhu; Lu, Yi; Qi, Jianping; Han, Jin; Tian, Zhiqiang; Xie, Yunchang; Hu, Fuqiang; Yuan, Hailong; Wu, Wei

    2014-02-01

    The main purpose of this study was to prepare binary lipids-based nanostructured lipid carriers to improve the oral bioavailability of silymarin, a poorly water-soluble liver protectant. Silymarin-loaded nanostructured lipid carriers were prepared by the method of high-pressure homogenization with glycerol distearates (Precirol ATO-5) and oleic acid as the solid and liquid lipids, respectively, and lecithin (Lipoid E 100) and Tween-80 as the emulsifiers. The silymarin-nanostructured lipid carrier prepared under optimum conditions was spherical in shape with mean particle size of ∼78.87 nm, entrapment efficiency of 87.55%, loading capacity of 8.32%, and zeta potential of -65.3 mV, respectively. In vitro release of silymarin-nanostructured lipid carriers was very limited even after 12 h, while in vitro lipolysis showed fast digestion of nanostructured lipid carriers within 1 h. Relative oral bioavailability of silymarin-nanostructured lipid carriers in Beagle dogs was 2.54- and 3.10-fold that of marketed Legalon® and silymarin solid dispersion pellets, respectively. It was concluded that nanostructured lipid carriers were potential drug delivery systems to improve the bioavailability of silymarin. Other than improved dissolution, alternative mechanisms such as facilitated absorption as well as lymphatic transport may contribute to bioavailability enhancement.

  5. High affinity, bioavailable 3-amino-1,4-benzodiazepine-based gamma-secretase inhibitors.

    Science.gov (United States)

    Owens, Andrew P; Nadin, Alan; Talbot, Adam C; Clarke, Earl E; Harrison, Timothy; Lewis, Huw D; Reilly, Michael; Wrigley, Jonathan D J; Castro, José L

    2003-11-17

    In this paper, we describe the development of a novel series of high affinity, orally bioavailable 3-amino-1,4 benzodiazepine-based gamma-secretase inhibitors for the potential treatment of Alzheimer's disease. We disclose structure-activity relationships based around the 1, 3 and 5 positions of the benzodiazepine core structure.

  6. Relative bioavailability of three newly developed albendazole formulations : a randomized crossover study with healthy volunteers

    NARCIS (Netherlands)

    Rigter, I M; Schipper, H G; Koopmans, R P; van Kan, H J M; Frijlink, H W; Kager, P A; Guchelaar, H-J

    2004-01-01

    This study of healthy volunteers shows that the relative bioavailability of albendazole formulations that use arachis oil-polysorbate 80 or hydroxypropyl-beta-cyclodextrin as an excipient was enhanced 4.3- and 9.7-fold compared to the results seen with commercial tablets. Administration of macrogol

  7. Palaeo-pollution from mining activities in the Vosges Mountains: 1000 years and still bioavailable.

    Science.gov (United States)

    Mariet, Anne-Lise; de Vaufleury, Annette; Bégeot, Carole; Walter-Simonnet, Anne-Véronique; Gimbert, Frédéric

    2016-07-01

    Mining and smelting activities have contaminated the environment with trace metals (TMs) at a worldwide scale for at least two millennia. A combination of chemical approaches and active biomonitoring was performed to analyse the environmental availability and bioavailability of TM palaeo-pollution in a former PbAg mining district in the Vosges Mountains, France. Along a soil TM contamination gradient that covered eight stations, including two archaeological mining sites, the toxicokinetics of six TMs (Pb, Cd, As, Ag, Co, Sb) in the snail Cantareus aspersus revealed that palaeo-pollution from the studied sites remains bioavailable. This study provides the first data on the accumulation kinetics of Ag and Co for C. aspersus. The environmental availability of the TMs was estimated with three chemical extraction methods (aqua regia, EDTA 50 mM, CaCl2 10 mM). Univariate regression analyses showed that EDTA extraction is the best method for estimating the bioavailability of Pb, As, Ag, Co and Sb to snails. None of the three extractants was efficient for Cd. A multivariate analysis of bioaccumulation data revealed that TM bioavailability and transfer were modulated by exposure sources (soil, humus and vegetation) rather than by soil physico-chemical characteristics. Hence, although the deposition of mining wastes dates back several centuries, these wastes still represent a source of contamination that must be considered to develop relevant site management and environmental risk assessment.

  8. The effects of soil amendments on heavy metal bioavailability in two contaminated Mediterranean soils

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.J.; Clemente, Rafael; Roig, Asuncion; Bernal, M.P

    2003-04-01

    The effects of organic amendments on metal bioavailability were not always related to their degree of humification. - Two heavy metal contaminated calcareous soils from the Mediterranean region of Spain were studied. One soil, from the province of Murcia, was characterised by very high total levels of Pb (1572 mg kg{sup -1}) and Zn (2602 mg kg{sup -1}), whilst the second, from Valencia, had elevated concentrations of Cu (72 mg kg{sup -1}) and Pb (190 mg kg{sup -1}). The effects of two contrasting organic amendments (fresh manure and mature compost) and the chelate ethylenediaminetetraacetic acid (EDTA) on soil fractionation of Cu, Fe, Mn, Pb and Zn, their uptake by plants and plant growth were determined. For Murcia soil, Brassica juncea (L.) Czern. was grown first, followed by radish (Raphanus sativus L.). For Valencia soil, Beta maritima L. was followed by radish. Bioavailability of metals was expressed in terms of concentrations extractable with 0.1 M CaCl{sub 2} or diethylenetriaminepentaacetic acid (DTPA). In the Murcia soil, heavy metal bioavailability was decreased more greatly by manure than by the highly-humified compost. EDTA (2 mmol kg{sup -1} soil) had only a limited effect on metal uptake by plants. The metal-solubilising effect of EDTA was shorter-lived in the less contaminated, more highly calcareous Valencia soil. When correlation coefficients were calculated for plant tissue and bioavailable metals, the clearest relationships were for Beta maritima and radish.

  9. Evaluation of a Florida coastal golf complex as a local and watershed source of bioavailable contaminants

    Science.gov (United States)

    Lewis, Michael A., Robert L. Quarles, Darrin D. Dantin and James C. Moore. 2004. Evaluation of a Coastal Golf Complex as a Local and Watershed Source of Bioavailable Contaminants. Mar. Pollut. Bull. 48(3-4):254-262. (ERL,GB 1183). Contaminant fate in coastal areas impacte...

  10. Sugars increase non-heme iron bioavailability in human epithelial intestinal and liver cells.

    Directory of Open Access Journals (Sweden)

    Tatiana Christides

    Full Text Available Previous studies have suggested that sugars enhance iron bioavailability, possibly through either chelation or altering the oxidation state of the metal, however, results have been inconclusive. Sugar intake in the last 20 years has increased dramatically, and iron status disorders are significant public health problems worldwide; therefore understanding the nutritional implications of iron-sugar interactions is particularly relevant. In this study we measured the effects of sugars on non-heme iron bioavailability in human intestinal Caco-2 cells and HepG2 hepatoma cells using ferritin formation as a surrogate marker for iron uptake. The effect of sugars on iron oxidation state was examined by measuring ferrous iron formation in different sugar-iron solutions with a ferrozine-based assay. Fructose significantly increased iron-induced ferritin formation in both Caco-2 and HepG2 cells. In addition, high-fructose corn syrup (HFCS-55 increased Caco-2 cell iron-induced ferritin; these effects were negated by the addition of either tannic acid or phytic acid. Fructose combined with FeCl3 increased ferrozine-chelatable ferrous iron levels by approximately 300%. In conclusion, fructose increases iron bioavailability in human intestinal Caco-2 and HepG2 cells. Given the large amount of simple and rapidly digestible sugars in the modern diet their effects on iron bioavailability may have important patho-physiological consequences. Further studies are warranted to characterize these interactions.

  11. Effects of hypertonic buffer composition on lymph node uptake and bioavailability of rituximab, after subcutaneous administration.

    Science.gov (United States)

    Fathallah, Anas M; Turner, Michael R; Mager, Donald E; Balu-Iyer, Sathy V

    2015-03-01

    The subcutaneous administration of biologics is highly desirable; however, incomplete bioavailability after s.c. administration remains a major challenge. In this work we investigated the effects of excipient dependent hyperosmolarity on lymphatic uptake and plasma exposure of rituximab as a model protein. Using Swiss Webster (SW) mice as the animal model, we compared the effects of NaCl, mannitol and O-phospho-L-serine (OPLS) on the plasma concentration of rituximab over 5 days after s.c. administration. An increase was observed in plasma concentrations in animals administered rituximab in hypertonic buffer solutions, compared with isotonic buffer. Bioavailability, as estimated by our pharmacokinetic model, increased from 29% in isotonic buffer to 54% in hypertonic buffer containing NaCl, to almost complete bioavailability in hypertonic buffers containing high dose OPLS or mannitol. This improvement in plasma exposure is due to the improved lymphatic trafficking as evident from the increase in the fraction of dose trafficked through the lymph nodes in the presence of hypertonic buffers. The fraction of the dose trafficked through the lymphatics, as estimated by the model, increased from 0.05% in isotonic buffer to 13% in hypertonic buffer containing NaCl to about 30% for hypertonic buffers containing high dose OPLS and mannitol. The data suggest that hypertonic solutions may be a viable option for improving s.c. bioavailability.

  12. Bioavailable and biodegradable dissolved organic nitrogen in activated sludge and trickling filter wastewater treatment plants

    Science.gov (United States)

    A study was carried out to understand the fate of biodegradable dissolved organic nitrogen (BDON) and bioavailable dissolved organic nitrogen (ABDON) along the treatment trains of a wastewater treatment facility (WWTF) equipped with an activated sludge (AS) system and a WWTF equipped with a two-stag...

  13. Bioavailability of dietary polyphenols: Factors contributing to their clinical application in CNS diseases.

    Science.gov (United States)

    Pandareesh, M D; Mythri, R B; Srinivas Bharath, M M

    2015-10-01

    The anatomical location of the central nervous system (CNS) renders it immunologically and pharmacologically privileged due to the blood brain barrier (BBB). Although this limits the transport of unfavorable molecules to the CNS, the ensuing privilege could be disadvantageous for therapeutic compounds. Hence, the greatest challenge in the pharmacotherapy of CNS diseases is to ensure efficient brain targeting and drug delivery. Research evidences indicate that dietary polyphenols have neuroprotective potential against CNS diseases. However, their selective permeability across BBB, poor absorption, rapid metabolism and systemic elimination limit their bioavailability and therapeutic efficacy. Consequently, the beneficial effects of these orally administered agents in the CNS still remain a subject of debate. This has also limited its clinical application either as independent or adjunctive therapy. Improving the in vivo bioavailability by novel methods could improve the therapeutic feasibility of polyphenols and assist in evolving novel drugs and their derivatives with improved efficacy in vivo. Here we review the mechanistic and pharmacological issues related to the bioavailability of polyphenols with therapeutic implications for CNS diseases. We surmise that improving the bioavailability of polyphenols entails efficient in vivo transport across BBB, biochemical stability, improved half-life and persistent neuroprotection in the CNS.

  14. Host-related factors explaining interindividual variability of carotenoid bioavailability and tissue concentrations in humans

    NARCIS (Netherlands)

    Bohn, Torsten; Desmarchelier, Charles; Dragsted, Lars O.; Nielsen, Charlotte S.; Stahl, Wilhelm; Rühl, Ralph; Keijer, Jaap; Borel, Patrick

    2017-01-01

    Carotenoid dietary intake and their endogenous levels have been associated with a decreased risk of several chronic diseases. There are indications that carotenoid bioavailability depends, in addition to the food matrix, on host factors. These include diseases (e.g. colitis), life-style habits (e

  15. Familial hypercholesterolemia impairs exercise-induced systemic vasodilation due to reduced NO bioavailability

    NARCIS (Netherlands)

    V.J. de Beer (Vincent Jacob); D. Merkus (Daphne); S.B. Bender (Shawn ); D.L. Tharp (Darla); D.K. Bowles; D.J.G.M. Duncker (Dirk); H. Laughlin (Harold)

    2013-01-01

    textabstractFamilial hypercholesterolemia impairs exercise-induced systemic vasodilation due to reduced NO bioavailability. J Appl Physiol 115: 17671776, 2013. First published October 24, 2013; doi:10.1152/japplphysiol.00619.2013. Hypercholesterolemia impairs endothelial function [e.g., the nitric o

  16. Zn and Fe biofortification: the right chemical environment for human bioavailability.

    Science.gov (United States)

    Clemens, Stephan

    2014-08-01

    A considerable fraction of global disease burden and child mortality is attributed to Fe and Zn deficiencies. Biofortification, i.e. the development of plants with more bioavailable Zn and Fe, is widely seen as the most sustainable solution, provided suitable crops can be generated. In a cereal-dominated diet availability of Fe and Zn for absorption by the human gut is generally low and influenced by a highly complex chemistry. This complexity has mostly been attributed to the inhibitory effect of Fe and Zn binding by phytate, the principal phosphorus storage compound in cereal and legume seeds. However, phytate is only part of the answer to the multifaceted bioavailability question, albeit an important one. Recent analyses addressing elemental distribution and micronutrient speciation in seeds strongly suggest the existence of different Fe and Zn pools. Exploration of natural variation in maize showed partial separation of phytate levels and Fe bioavailability. Observations made with transgenic plants engineered for biofortification lend further support to this view. From a series of studies the metal chelator nicotianamine is emerging as a key molecule. Importantly, nicotianamine levels have been found to not only increase the loading of Fe and Zn into grains. Bioavailability assays indicate a strong activity of nicotianamine also as an enhancer of intestinal Fe and Zn absorption.

  17. Bioavailability and cellular effects of metals on Lumbricus terrestris inhabiting volcanic soils

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Andre [Departamento de Biologia, Universidade dos Acores, R. Mae de Deus, APT 1422, PT-9501-855 Ponta Delgada (Portugal)]. E-mail: aamaral@notes.uac.pt; Soto, Manu [Biologia Zelularra eta Histologia Laborategia, Zoologia eta Biologia Zelularra Saila, Zientzi Fakultatea, Euskal Herriko Unibertsitatea, 644 PK E-48080 Bilbao (Spain); Cunha, Regina [Departamento de Biologia, Universidade dos Acores, R. Mae de Deus, APT 1422, PT-9501-855 Ponta Delgada (Portugal); Marigomez, Ionan [Biologia Zelularra eta Histologia Laborategia, Zoologia eta Biologia Zelularra Saila, Zientzi Fakultatea, Euskal Herriko Unibertsitatea, 644 PK E-48080 Bilbao (Spain); Rodrigues, Armindo [Departamento de Biologia, Universidade dos Acores, R. Mae de Deus, APT 1422, PT-9501-855 Ponta Delgada (Portugal)

    2006-07-15

    Whether the radial thickness (RT) of the chloragogenous tissue and intestinal epithelium of earthworms (Lumbricus terrestris) reflects the bioavailability of metals in soils was investigated in two areas, one with active volcanism (Furnas) and another with no volcanic activity since 3 million years ago (Santa Maria), in the Azores. Metal contents in soil samples and earthworms from the two areas were analyzed. Autometallography and measurements of the RT were performed in the chloragogenous tissue and intestinal epithelium. Earthworms from the active volcanic area demonstrated lower RT of chloragogenous tissue and intestinal epithelium as well as higher levels of bioavailable metals, especially Zn and Cd. Comparison of bioavailable metal contents between both areas suggests a higher risk for uptake of potentially toxic metals in the active volcanic area than in the non-active volcanic area, which is reflected by the lower RT of the chloragogenous tissue and intestinal epithelium in the former. - In earthworms, differences in the chloragogenous tissue morphometry may be related to the bioavailability of metals in soils.

  18. Assessment of metal bioavailability in smelter-contaminated soil before and after lime amendment.

    Science.gov (United States)

    Bade, Rabindra; Oh, Sanghwa; Sik Shin, Won

    2012-06-01

    In this study, changes in bioavailable concentrations of Pb, Zn, Cu and As in former smelter site soils (J1 and J2) were investigated before and after lime amendment. The immobilization efficiencies of metal(loid)s were evaluated by Toxicity Characteristic Leaching Procedure (TCLP). Their bioavailable concentrations in the soils were evaluated by the acid-extractable and -reducible fractions in Standard Measurement and Testing Program (i.e., SM&T(I+II)), in vitro physiologically based extraction test (PBET) and diffusive gradients in thin-films (DGT). The results showed that the bioavailable concentrations remarkably decreased after lime amendment in both J1 and J2 soils. DGT uptake and resupply (R) of Zn, Cu and As from soil to soil solution increased but that of Pb decreased. This pattern was consistent with SM&T(I+II)- and PBET-extractable concentrations after lime amendment. This indicates that lime amendment is highly effective for the immobilization of Zn, Cu and As, but not for Pb. Our results implicate that DGT can be used to estimate bioavailability of metal(loid)s in soils and further extended to estimate risk reduction after soil remediation.

  19. How contamination sources and soil properties can influence the Cd and Pb bioavailability to snails.

    Science.gov (United States)

    Pauget, Benjamin; Gimbert, Frédéric; Coeurdassier, Mickael; Druart, Coline; Crini, Nadia; de Vaufleury, Annette

    2016-02-01

    To better understand the fate of metals in the environment, numerous parameters must be studied, such as the soil properties and the different sources of contamination for the organisms. Among bioindicators of soil quality, the garden snail (Cantareus aspersus) integrates multiple sources (e.g. soil, plant) and routes (e.g. digestive, cutaneous) of contamination. However, the contribution of each source on metal bioavailability and how soil properties influence these contributions have never been studied when considering the dynamic process of bioavailability. Using accumulation kinetics, this study showed that the main assimilation source of Cd was lettuce (68%), whereas the main source of Pb was the soil (90%). The plant contribution increased in response to a 2-unit soil pH decrease. Unexpectedly, an increase in the soil contribution to metal assimilation accompanied an increase in the organic matter (OM) content of the soil. For both metals, no significant excretion and influence of source on excretion have been modelled either during exposure or depuration. This study highlights how the contribution of different sources to metal bioavailability changes based on changes in soil parameters, such as pH and OM, and the complexity of the processes that modulate metal bioavailability.

  20. Using in vitro and in vivo models to evaluate the oral bioavailability of nutraceuticals.

    Science.gov (United States)

    Ting, Yuwen; Zhao, Qin; Xia, Chunxin; Huang, Qingrong

    2015-02-11

    Nutraceuticals are the bioactive compounds found in many dietary sources. Numerous publications have reported their ability to prevent the development of degenerative diseases through modulation of physiological and physiochemical processes in living systems. Having sufficient concentration at the target site of action is the most critical factor for nutraceuticals to deliver the health benefits. For consumers, it is commonly accepted to ingest these bioactive components through oral delivery route because it is convenient and cost-efficient and allows flexible dosing schedule. Thus, it is important to understand the oral bioavailability of nutraceuticals to evaluate their qualifications as disease preventive agents and to calculate the required ingestion dosages. To predict the oral bioavailability of nutraceuticals, many in vitro and in vivo models have been developed to reduce the need for frequent human pharmacokinetic studies, which are costly and time-consuming and involve ethical complications. These models evaluate one or more of the influential factors that contribute to the oral bioavailability and are efficient screening techniques with the potential of predicting the pharmacokinetic process in humans. To accurately predict human oral bioavailability, further research is required to develop not only a better correlation between the in vitro and in vivo models but also an accurate scaling factor that takes into account interspecies variations.

  1. Bioavailability and biodegradation of nonylphenol in sediment determined with chemical and bioanalysis

    NARCIS (Netherlands)

    Weert, J. de; Cal, A. de la; Berg, H. van den; Murk, A.; Langenhoff, A.; Rijnaarts, H.; Grotenhuis, T.

    2008-01-01

    The surfactant nonylphenol (NP) is an endocrine-disrupting compound that is widely spread throughout the environment. Although environmental risk assessments are based on total NP concentrations, only the bioavailable fraction posses an environmental risk. The present study describes the bioavailabi

  2. Bioavailability of selenium from fish, yeast and selenate: A comparative study in humans using stable isotopes

    NARCIS (Netherlands)

    Fox, T.E.; Heuvel, E.G.H.M. van den; Atherton, C.A.; Dainty, J.R.; Lewis, D.J.; Langford, N.J.; Crews, H.M.; Luten, J.B.; Lorentzen, M.; Sieling, F.W.; Aken-Schneyder, P. van; Hoek, M.; Kotterman, M.J.J.; Dael, P. van; Firweather-Tail, S.J.

    2004-01-01

    Objective: To measure the bioavailability of selenium from cooked and raw fish in humans by estimating and comparing apparent absorption and retention of selenium in biosynthetically labelled fish with labelled selenate and biosynthetically labelled selenium in brewers yeast. Design: The interventio

  3. Effect of piperine on the bioavailability and pharmacokinetics of emodin in rats.

    Science.gov (United States)

    Di, Xin; Wang, Xin; Di, Xin; Liu, Youping

    2015-11-10

    Emodin (1,3,8-trihydroxy-6-methylanthraquinone) has been widely used as a traditional medicine and was shown to possess a multitude of health-promoting properties in pre-clinical studies, but its bioavailability was low due to the extensive glucuronidation in liver and intestine, hindering the development of emodin as a feasible chemopreventive agent. In this study, piperine, as a bioenhancer, was used to enhance the bioavailability of emodin by inhibiting its glucuronidation. The pharmacokinetic profiles of emodin after oral administration of emodin (20mg/kg) alone and in combination with piperine (20mg/kg) to rats were investigated via a validated LC/MS/MS method. As the in vivo pharmacokinetic studies had indicated, the AUC and Cmax of emodin were increased significantly after piperine treatment, and the glucuronidation of emodin was markedly inhibited. Our study demonstrated that piperine significantly improved the in vivo bioavailability of emodin and the influence of piperine on the pharmacokinetics of emodin may be attributed to the inhibition of glucuronidation of emodin. Further research is needed to investigate the detailed mechanism of improved bioavailability of emodin via its combination with piperine.

  4. Bioavailability and biodistribution of differently charged polystyrene nanoparticles upon oral exposure in rats

    NARCIS (Netherlands)

    Walczak, A.P.; Hendriksen, P.J.M.; Woutersen, R.A.; Zande, M. van der; Undas, A.K.; Helsdingen, R.; Berg, H.H.J. van den; Rietjens, I.M.C.M.; Bouwmeester, H.

    2015-01-01

    The likelihood of oral exposure to nanoparticles (NPs) is increasing, and it is necessary to evaluate the oral bioavailability of NPs. In vitro approaches could help reducing animal studies, but validation against in vivo studies is essential. Previously, we assessed the translocation of 50 nm polys

  5. Influence of deposition and spray pattern of nasal powders on insulin bioavailability.

    Science.gov (United States)

    Pringels, E; Callens, C; Vervaet, C; Dumont, F; Slegers, G; Foreman, P; Remon, J P

    2006-03-01

    The influence of the deposition pattern and spray characteristics of nasal powder formulations on the insulin bioavailability was investigated in rabbits. The formulations were prepared by freeze drying a dispersion containing a physical mixture of drum dried waxy maize starch (DDWM)/Carbopol 974P (90/10, w/w) or a spray-dried mixture of Amioca starch/Carbopol 974P (25/75, w/w). The deposition in the nasal cavity of rabbits and in a silicone human nose model after actuation of three nasal delivery devices (Monopowder, Pfeiffer and experimental system) was compared and related to the insulin bioavailability. Posterior deposition of the powder formulation in the nasal cavity lowered the insulin bioavailability. To study the spray pattern, the shape and cross-section of the emitted powder cloud were analysed. It was concluded that the powder bulk density of the formulation influenced the spray pattern. Consequently, powders of different bulk density were prepared by changing the solid fraction of the freeze dried dispersion and by changing the freezing rate during freeze drying. After nasal delivery of these powder formulations no influence of the powder bulk density and of the spray pattern on the insulin bioavailability was observed.

  6. Towards bioavailability-based soil criteria: past, present and future perspectives

    NARCIS (Netherlands)

    Naidu, R.; Channey, R.; McConnell, S.; Johnston, N.; Semple, K.T.; McGrath, S.; Dries, V.; Nathanail, P.; Harmsen, J.; Pruszinski, A.; MacMillan, J.

    2015-01-01

    Bioavailability has been used as a key indicator in chemical risk assessment yet poorly quantified risk factor. Worldwide, the framework used to assess potentially contaminated sites is similar, and the decisions are based on threshold contaminant concentration. The uncertainty in the definition and

  7. Bioavailability, Bioequivalence and Therapeutic Equivalence: Concepts and Issues for Pharmacy Students.

    Science.gov (United States)

    Edwards, David J.

    1990-01-01

    A lecture given in courses in applied pharmacokinetics at Wayne State University, Michigan, is presented. The definition of bioavailability is reviewed along with methods of calculation, bioequivalence, criteria for establishing bioequivalence of a new product, essentials of a bioequivalence study, and the relationship between bioequivalence and…

  8. Stability in fish feed and bioavailability to rainbow trout of two ascorbic acid forms

    DEFF Research Database (Denmark)

    Skelbaek, T.; Andersen, Niels Gerner; Winning, M.

    1990-01-01

    The stability in warm pelleted fish feed and the bioavailability to rainbow trout of crystalline ascorbic acid (AA) and a synthetic polymer-coated AA product (PCAA) were compared. The AA loss during pelleting was 29% for crystalline AA and 19% for PCAA. After 6 weeks at room temperature 73% of PCAA...

  9. Interchangeability of gabapentin generic formulations in the Netherlands: a comparative bioavailability study

    NARCIS (Netherlands)

    Yu, Y.; Teerenstra, S.; Vanmolkot, F.; Neef, C.; Burger, D.M.; Maliepaard, M.

    2013-01-01

    To investigate the so-called "drift" with generic-generic drug substitution, a single-dose, four-way crossover comparative bioavailability study was performed involving 24 healthy subjects and three generic and one branded formulation of a tablet containing 800 mg gabapentin as test medication. The

  10. Increased understanding of the cereal phytase complement for better mineral bio-availability and resource management

    DEFF Research Database (Denmark)

    Brinch-Pedersen, Henrik; Madsen, Claus Krogh; Holme, Inger Bæksted

    2014-01-01

    for the bio-availability of micronutrients in human nutrition. The composition and levels of mature grain phytase activity (MGPA) in cereals is of central importance for efficient phytate hydrolysis. The MGPA varies considerably between species. Substantial activity is present in Triticeae tribe cereals like...

  11. Development of an integrated in vitro model for the prediction of oral bioavailability of nanoparticles

    NARCIS (Netherlands)

    Walczak, A.P.

    2015-01-01

    Title of the PhD thesis: Development of an integrated in vitro model for the prediction of oral bioavailability of nanoparticles The number of food-related products containing nanoparticles (NPs) increases. To understand the safety of such products, the potential uptake of these NPs

  12. Organically complexed iron enhances bioavailability of antimony to maize (Zea mays) seedlings in organic soils.

    Science.gov (United States)

    Ptak, Corey; McBride, Murray

    2015-12-01

    Antimony (Sb) is a metalloid belonging to group 15 of the periodic table. Chemical similarities between arsenic (As) and Sb produce concerns about potential health effects of Sb and enrichment in the environment. Antimony is found in oxic environments predominately as an oxyanionic species, antimonite (Sb[OH](6-)). As a result of its net negative charge, Sb[OH](6-) was not initially predicted to have strong interactions with natural organic matter. Oxyanionic species could bind the negatively charged organic matter via a ternary complexation mechanism, in which cationic metals mediate the strong association between organic matter functional groups and oxyanions. However, these interactions are poorly understood in how they influence the bioavailability of oxyanionic contaminants to plants. Iron (Fe) additions to organic soils have been found to increase the number of organically complexed Fe sites suitable for Sb exchange, resulting in a reduced bioavailable fraction of Sb. The bioavailability of Sb to maize seedlings as a function of organically complexed Fe was examined using a greenhouse study. A significant increase in plant tissue Sb was observed as organically complexed Fe increased, which was not predicted by methods commonly used to assess bioavailable Sb. Extraction of soils with organic acids common to the maize rhizosphere suggested that organic acid exudation can readily mobilize Sb bound by organic Fe complexes.

  13. Enhancement of absorption and bioavailability of echinacoside by verapamil or clove oil

    Directory of Open Access Journals (Sweden)

    Shen JY

    2015-08-01

    Full Text Available Jin-Yang Shen,1,* Xiao-Lin Yang,2,* Zhong-Lin Yang,1 Jun-Ping Kou,1 Fei Li11State Key Laboratory of Natural Medicines, China Pharmaceutical University, 2Key Laboratory of Pharmaceutical and Biological Marine Resources Research and Development of Jiangsu Province, Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China*These authors contributed equally to this workPurpose: This present study investigated the absorption kinetics of echinacoside (ECH in situ and in vitro and its oral bioavailability in rats. Additional aim was to find an agent(s to promote ECH absorption and oral bioavailability among two efflux proteins and three absorption promoters.Methods: ECH absorption behaviors were investigated by everted gut sac model in vitro and single-pass intestinal perfusion model in situ. Pharmacokinetics study was performed to investigate the influences of verapamil and clove oil on ECH bioavailability in vivo. All samples were measured at different time intervals by high performance liquid chromatography.Results: The results showed that the effective permeability coefficient (Peff and apparent permeability coefficient of ECH were 0.83×10-6–3.23×10-6 cm/s and 2.99×10-6–9.86×10-6 cm/s, respectively. The Peff among duodenum, jejunum, and ileum were not statistically different, but they were higher than colon (P<0.01, which demonstrated that intestinal ECH absorption was poor and site dependent. Additionally, verapamil and clove oil significantly increased the jejunal Peff of ECH both in situ and in vitro. Moreover, the bioavailability of ECH in combination with verapamil and clove oil were increased by 1.37-fold (P<0.05 and 2.36-fold (P<0.001, respectively, when compared to ECH group. Overall, verapamil and clove oil facilitated ECH absorption and oral bioavailability.Conclusion: The absorption and bioavailability of ECH were enhanced by verapamil and clove oil, respectively, both in vitro and in vivo. Consequently

  14. Biochemical indicators for the bioavailability of organic carbon in ground water

    Science.gov (United States)

    Chapelle, F.H.; Bradley, P.M.; Goode, D.J.; Tiedeman, C.; Lacombe, P.J.; Kaiser, K.; Benner, R.

    2009-01-01

    The bioavailability of total organic carbon (TOC) was examined in ground water from two hydrologically distinct aquifers using biochemical indicators widely employed in chemical oceanography. Concentrations of total hydrolyzable neutral sugars (THNS), total hydrolyzable amino acids (THAA), and carbon-normalized percentages of TOC present as THNS and THAA (referred to as "yields") were assessed as indicators of bioavailability. A shallow coastal plain aquifer in Kings Bay, Georgia, was characterized by relatively high concentrations (425 to 1492 ??M; 5.1 to 17.9 mg/L) of TOC but relatively low THNS and THAA yields (???0.2%-1.0%). These low yields are consistent with the highly biodegraded nature of TOC mobilized from relatively ancient (Pleistocene) sediments overlying the aquifer. In contrast, a shallow fractured rock aquifer in West Trenton, New Jersey, exhibited lower TOC concentrations (47 to 325 ??M; 0.6 to 3.9 mg/L) but higher THNS and THAA yields (???1% to 4%). These higher yields were consistent with the younger, and thus more bioavailable, TOC being mobilized from modern soils overlying the aquifer. Consistent with these apparent differences in TOC bioavailability, no significant correlation between TOC and dissolved inorganic carbon (DIC), a product of organic carbon mineralization, was observed at Kings Bay, whereas a strong correlation was observed at West Trenton. In contrast to TOC, THNS and THAA concentrations were observed to correlate with DIC at the Kings Bay site. These observations suggest that biochemical indicators such as THNS and THAA may provide information concerning the bioavailability of organic carbon present in ground water that is not available from TOC measurements alone.

  15. Enhancement of Bioavailability and Pharmacodynamic Effects of Thymoquinone Via Nanostructured Lipid Carrier (NLC) Formulation.

    Science.gov (United States)

    Elmowafy, Mohammed; Samy, Ahmed; Raslan, Mohamed A; Salama, Ayman; Said, Ragab A; Abdelaziz, Abdelaziz E; El-Eraky, Wafaa; El Awdan, Sally; Viitala, Tapani

    2016-06-01

    Thymoquinone (TQ), obtained from black cumin (Nigella sativa), is a natural product with anti-oxidant, anti-inflammatory, and hepatoprotective effects but unfortunately with poor bioavailability. Aiming to improve its poor oral bioavailability, TQ-loaded nanostructured lipid carriers (NLCs) were prepared by high-speed homogenization followed by ultrasonication and evaluated in vitro. Bioavailability and pharmacodynamic studies were also performed. The resultant NLCs showed poor physical homogeneity in Compritol 888 ATO Pluronic F127 system which consequently produced larger particle size and polydispersity index, smaller zeta potential values, and lower short-term (30 days) physical stability than other systems. Encapsulation efficiency percentage (EE%) lied between 84.6 ± 5% and 96.2 ± 1.6%. TQ AUC0-t values were higher in animals treated with NLCs, with a relative bioavailability of 2.03- and 3.97-fold (for F9 and F12, respectively) higher than TQ suspension, indicating bioavailability enhancement by NLC formulation. Hepatoprotective effects of F12 showed significant (P < 0.05) decrease in both serum alanine amino transferase and aspartate amino transferase to reach 305.0 ± 24.88 and 304.7 ± 23.55 U/ml, respectively, when compared with untreated toxic group. Anti-oxidant efficacy of F12 showed significant (P < 0.05) decline of malondialdehyde and elevation of reduced glutatione. This improvement was also confirmed histopathologically.

  16. Novel electrosprayed nanospherules for enhanced aqueous solubility and oral bioavailability of poorly water-soluble fenofibrate

    Science.gov (United States)

    Yousaf, Abid Mehmood; Mustapha, Omer; Kim, Dong Wuk; Kim, Dong Shik; Kim, Kyeong Soo; Jin, Sung Giu; Yong, Chul Soon; Youn, Yu Seok; Oh, Yu-Kyoung; Kim, Jong Oh; Choi, Han-Gon

    2016-01-01

    Purpose The purpose of the present research was to develop a novel electrosprayed nanospherule providing the most optimized aqueous solubility and oral bioavailability for poorly water-soluble fenofibrate. Methods Numerous fenofibrate-loaded electrosprayed nanospherules were prepared with polyvinylpyrrolidone (PVP) and Labrafil® M 2125 as carriers using the electrospray technique, and the effect of the carriers on drug solubility and solvation was assessed. The solid state characterization of an optimized formulation was conducted by scanning electron microscopy, powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopic analyses. Oral bioavailability in rats was also evaluated for the formulation of an optimized nanospherule in comparison with free drug and a conventional fenofibrate-loaded solid dispersion. Results All of the electrosprayed nanospherule formulations had remarkably enhanced aqueous solubility and dissolution compared with free drug. Moreover, Labrafil M 2125, a surfactant, had a positive influence on the solubility and dissolution of the drug in the electrosprayed nanospherule. Increases were observed as the PVP/drug ratio increased to 4:1, but higher ratios gave no significant increases. In particular, an electrosprayed nanospherule composed of fenofibrate, PVP, and Labrafil M 2125 at the weight ratio of 1:4:0.5 resulted in a particle size of amorphous state. It demonstrated the highest solubility (32.51±2.41 μg/mL), an excellent dissolution (~85% in 10 minutes), and an oral bioavailability ~2.5-fold better than that of the free drug. It showed similar oral bioavailability compared to the conventional solid dispersion. Conclusion Electrosprayed nanospherules, which provide improved solubility and bioavailability, are promising drug delivery tools for oral administration of poorly water-soluble fenofibrate. PMID:26834471

  17. Impact of bioavailability restrictions on microbially induced stable isotope fractionation. 1. Theoretical calculation.

    Science.gov (United States)

    Thullner, Martin; Kampara, Makeba; Richnow, Hans H; Harms, Hauke; Wick, Lukas Y

    2008-09-01

    The microbial degradation of organic substrates often exhibits a fractionation of stable isotopes which leads to an enrichment of the heavier isotope in the remaining substrate. The use of this effect to quantify the amount of biodegraded substrate in contaminated aquifers requires that the isotope fractionation factor is constant in time and space. In many natural and engineered systems the bioavailable concentration at the location of the enzymes differs from the average bulk concentration of the substrate. When enzymatically driven substrate degradation is coupled to a preceding transport step controlling the bioavailability of the substrate, the observed isotope fractionation becomes a function of the bulk substrate concentration. The sensitivity of the observed isotope fractionation factor toward such substrate concentration changes depends on the ratio of bulk substrate concentration and Michaelis-Menten constant and on the ratio between the specific affinity of the microorganisms toward the substrate and the first order rate constant of the bioavailability limiting transport process. Highest sensitivities toward substrate concentration were found for combinations of high substrate concentration with low substrate bioavailability (i.e., high ratios of substrate concentration and Michaelis-Menten constant, and high ratios of specific affinity and transport rate constant). As a consequence, changes in concentration and isotopic composition of a bioavailability limited substrate in batch experiments should not exhibit a linear relation in a Rayleigh plot, and the slope of the Rayleigh plot should show a decreasing trend with concentration decrease. When using isotope fractionation to quantify biodegradation along groundwater flow paths, changes in observed isotope fractionation might occur while contaminant concentration decreases along a flow path.

  18. Evaluation of iron bioavailability in a mixture of cereals, seeds, and grains ("Human Ration"

    Directory of Open Access Journals (Sweden)

    Bárbara Nery Enes

    2014-03-01

    Full Text Available Iron bioavailability was evaluated in three mixtures of cereals, seeds, and grains ("Human Ration": light, regular, and homemade provided to rats. The animals received an iron depletion diet for 21 days, followed by a repletion diet containing 12 mg·kg-1 of iron for 14 days. The hemoglobin regeneration efficiency and the relative biological value did not differ between the light mixture and control group. The iron bioavailability of the light mixture of cereals, seeds, and grains and the control group were 99.99±27.62 and 80.02±36.63, respectively, while the regular and homemade mixtures of cereals, seeds, and grains showed lower iron bioavailability, 50.12±35.53 and 66.66±15.44, respectively; the iron content of the diet with light cereal mixture light was statistically similar to that of the control (ferrous sulfate 99.99±27.62. The high content of tannin (202.81±19.53 mg·100-1 in the diet with the regular cereal mixture may have contributed to its low iron bioavailability. The higher intake of soluble fiber by the animals fed the light mixture (21.15±0.92 g was moderately correlated (r=0.5712, p=0.0018 with the concentration of propionate in the caecal bulk (65.49±11.08 µmol/g. The short chain fatty acids produced by soluble fiber fermentation, associated with the low-content of tannin may have improved iron solubility and absorption in the light cereal mixture diet. The iron bioavailability in the light mixture of cereals, seeds, and grains was similar to that of ferrous sulfate.

  19. Stimulating in situ surfactant production to increase contaminant bioavailability and augment bioremediation of petroleum hydrocarbons

    Science.gov (United States)

    Haws, N. W.; Bentley, H. W.; Yiannakakis, A.; Bentley, A. J.; Cassidy, D. P.

    2006-12-01

    The effectiveness of a bioremediation strategy is largely dependent on relationships between contaminant sequestration (geochemical limitations) and microbial degradation potential (biological limitations). As contaminant bioavailability becomes mass transfer limited, contaminant removal will show less sensitivity to biodegradation enhancements without concurrent enhancements to rates of mass transfer into the bioavailable phase. Implementing a strategy that can simultaneously address geochemical and biological limitations is motivated by a subsurface zone of liquid petroleum hydrocarbons (LPH) contamination that is in excess of 10 acres (40,000 sq. meters). Biodegradation potential at the site is high; however, observed biodegradation rates are generally low, indicative of bioavailability limitations (e.g., low aqueous solubilities, nutrient deficiencies, and/or mass transfer limitations), and estimates indicate that bioremediation (i.e., biosparging/bioventing) with unaugmented biodegradation may be unable to achieve the remedial objectives within an acceptable time. Bench-scale experiments using soils native to the site provide evidence that, in addition to nutrient additions, a pulsed oxygen delivery can increase biodegradation rates by stimulating the microbial production of biosurfactants (rhamnolipids), leading to a reduction in surface tension and an increase in contaminant bioavailability. Pilot-scale tests at the field site are evaluating the effectiveness of stimulating in situ biosurfactant production using cyclic biosparging. The cyclic sparging creates extended periods of alternating aerobic and oxygen-depleted conditions in the submerged smear zone. The increased bioavailability of LPH and the resulting biodegradation enhancements during the test are evaluated using measurements of surface tension (as confirmation of biosurfactant accumulation) and nitrate concentrations (as substantiation of anaerobic biodegradation during shut-off periods). The

  20. Bioavailability of cadmium adsorbed on various oxides minerals to wetland plant species Phragmites australis

    Energy Technology Data Exchange (ETDEWEB)

    Wang He, E-mail: he.wangworld@yahoo.com.cn [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China); Jia Yongfeng, E-mail: yongfeng.jia@iae.ac.cn [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Wang Shaofeng [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Zhu Huijie; Wu Xing [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China)

    2009-08-15

    The bioavailability of heavy metals strongly depends on their speciation in the environment. The effect of different chemical speciations of cadmium ions (i.e. adsorbed on different oxide minerals) on its bioavailability to wetland plant Phragmites australis was studied. Goethite, magnetite, gibbsite, alumina, and manganese oxide were chosen as representatives of metal (hydr)oxides commonly present in sediment. The cultivar system with Hoagland solution as nutrition supply, and single metal oxide with adsorbed Cd as contaminant was applied to study Cd accumulation by P. australis. The bioaccumulation degree in root after the 45-day treatment followed the order: Al(OH){sub 3} > Al{sub 2}O{sub 3} > Fe{sub 3}O{sub 4} > MnO{sub 2} > FeOOH. The concentration of Cd in stem and leaf followed a similar order although it was considerably lower than that in root. Low-molecular-weight organic acids (LMWOAs), acetic acid, malic acid and citric acid were used to evaluate the desorbability of Cd from different oxides, which can be indicative of Cd-oxide bonding strength and Cd bioavailability. Desorption of Cd by acetic acid and malic acid followed the order: Al(OH){sub 3} > Fe{sub 3}O{sub 4} > Al{sub 2}O{sub 3} > FeOOH > MnO{sub 2}, while by citric acid: Al(OH){sub 3} {>=} Al{sub 2}O{sub 3} > Fe{sub 3}O{sub 4} > FeOOH > MnO{sub 2}. This was consistent with the Cd accumulation degree in the plant. Cd adsorbed on Al(OH){sub 3} was the most easily desorbable species and most bioavailable to P. australis among the oxide minerals, whereas MnO{sub 2} adsorbed Cd was least desorbable by LMWOAs hence constituted the least bioavailable Cd species adsorbed on the oxide minerals.

  1. Omega-3 long chain fatty acid "bioavailability": a review of evidence and methodological considerations.

    Science.gov (United States)

    Ghasemifard, Samaneh; Turchini, Giovanni M; Sinclair, Andrew J

    2014-10-01

    This review considers the bioavailability of different forms of omega-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA), including ethyl esters (EEs), free fatty acids (FFAs), triacylglycerols (TAGs) and phospholipids (PLs). The retrieved studies include short-term and longer-term studies in humans, and a number of animal studies, which were highly heterogeneous in their design making it difficult to draw substantiated conclusions. The apparent bioavailability (as defined by the authors of these studies) seems to be lowest for the EE form and highest for the FFA form, whilst no conclusion can be made for TAG versus PL from human data. Animal studies suggest that there are substantial differences in the bioavailability of PL form of LC-PUFA compared with the TAG form. This apparent limited knowledge and understanding is fundamentally driven by methodological limitations of these studies. The major limitations with the studies to date include: (between studies) loose definition of the term "bioavailability", lack of standardisation of analytical methodology, and differences in which blood compartment was analysed; (within a study) failure to provide equal amounts the n-3 LC-PUFA of the different forms being compared, failure to provide the dose of n-3 LC-PUFA on a body weight basis, failure to measure fatty acid excretion, failure to control the total fat intake, and failure to adequately power the studies from a statistical point of view. This review has laid out a set of suggestions and criteria for conducting future studies on the bioavailability of different chemical forms of n-3 LC-PUFA.

  2. Enhancing the Delivery of Resveratrol in Humans: If Low Bioavailability is the Problem, What is the Solution?

    Directory of Open Access Journals (Sweden)

    James M. Smoliga

    2014-10-01

    Full Text Available Resveratrol has emerged as a leading candidate for improving healthspan through potentially slowing the aging process and preventing chronic diseases. The poor bioavailability of resveratrol in humans has been a major concern for translating basic science findings into clinical utility. Although a number of positive findings have emerged from human clinical trials, there remain many conflicting results, which may partially be attributed to the dosing protocols used. A number of theoretical solutions have been developed to improve the bioavailability of resveratrol, including consumption with various foods, micronized powders, combining it with additional phytochemicals, controlled release devices, and nanotechnological formulations. While laboratory models indicate these approaches all have potential to improve bioavailability of resveratrol and optimize its clinical utility, there is surprisingly very little data regarding the bioavailability of resveratrol in humans. If bioavailability is indeed a limitation in the clinical utility of resveratrol, there is a need to further explore methods to optimize bioavailability in humans. This review summarizes the current bioavailability data, focusing on data from humans, and provides suggested directions for future research in this realm.

  3. Influence of compost addition on lead and arsenic bioavailability in reclaimed orchard soil assessed using Porcellio scaber bioaccumulation test.

    Science.gov (United States)

    Udovic, M; McBride, M B

    2012-02-29

    Long-term application of lead arsenate in orchards has led to a significant accumulation of Pb and As in the topsoil. Reclamation of old orchards for agricultural purposes entails the exposure of humans to Pb and As, which can be reduced by adequate remediation actions. In this study, we assessed the remediation efficiency of compost addition, commonly used as a sustainable agricultural practice, in decreasing the human exposure Pb and As by direct ingestion. The remediation was evaluated based on Pb and As bioavailability, assessed by means of a selective non-exhaustive chemical extraction (modified Morgan extraction, MME), with a physiologically based extraction test (PBET) for the assessment of Pb and As bioavailability in ingested soils and with a novel in vivo bioaccumulation test with isopods (Porcellio scaber). All the tests showed that compost addition consistently reduced Pb, but increased As potential bioavailability. The bioaccumulation test with P. scaber was sensitive to changes in Pb and As bioavailability in test soils. However, the results indicate that the bioavailability of As could be under- or overestimated using solely chemical extraction tests. Indirect assessment of trace metal bioavailability with bioaccumulation in isopods can be used as complementary source of data to the existing in vitro chemical extraction test approach for the estimation of human exposure to trace elements in polluted and remediated soil. This is the first report on the use of As accumulation in P. scaber as a tool for the assessment of As bioavailability in contaminated orchard soil.

  4. Bioavailability of persistent organic pollutants in soils and sediments--a perspective on mechanisms, consequences and assessment.

    Science.gov (United States)

    Reid, B J; Jones, K C; Semple, K T

    2000-04-01

    It has been observed that as soil-pollutant contact time increases, pollutant bioavailability and extractability decreases. This phenomenon has been termed 'ageing'. Decreased chemical extractability with increased soil-chemical contact time is evident where both 'harsh' techniques, e.g. dichloromethane Soxhlet extraction, and 'non-exhaustive' techniques, e.g. butanol shake extraction, have been used. It has also been observed that the amount of chemical extracted by these techniques varies considerably over time. Similarly, decreases in bioavailability with increased soil-pollutant contact time have been described in bacterial, earthworm and other organism studies. From these investigations, it has been shown that the fraction of pollutant determined to be bioavailable can vary between organisms. Thus, there is an immediate definition problem, what is bioavailability? Additionally, if bioavailability is to be assessed by a chemical means, which organisms should (or can) be mimicked by the extraction procedure? This review provides a background to the processes inherent to ageing, a discussion of its consequences on bioavailability and ends with some reflections on the appropriateness of chemical extraction techniques to mimic bioavailability

  5. Bioavailability of the digestible lysine and total sulfur amino acids in meat and bone meals varying in protein quality.

    Science.gov (United States)

    Wang, X; Parsons, C M

    1998-07-01

    Experiments were conducted to determine whether the digestible Lys, Met, and TSAA in a high and low quality meat and bone meal (MBM) were totally bioavailable for protein synthesis in chicks. True digestibility of amino acids (AA) in the two MBM was determined by the precision-fed cecectomized rooster assay. Bioavailability of the digestible AA was then assessed in three slope-ratio chick growth assays using Lys-, Met-, or TSAA-deficient crystalline AA basal diets that were supplemented with varying levels of the test AA, high or low quality MBM, or AA mixtures simulating the mean digestible AA composition of the high and low quality MBM. Response parameters were weight gain, feed efficiency, body N gain, and body Lys gain in the Lys assay and weight gain and feed efficiency in the Met and TSAA assays. Bioavailability values for the digestible Lys, Met, and TSAA in the MBM and AA mixtures simulating MBM varied depending on response parameter, with values based on feed efficiency generally being highest. No consistent differences in bioavailability of the digestible AA were observed between the two MBM when all AA were considered; however, the bioavailability of the digestible Lys in the low quality MBM was lower than that in the high quality MBM for two of four performance criteria. When considering all response parameters and the AA mixture results, bioavailability of the digestible Lys and Met in the two MBM was generally 90% or greater, whereas bioavailability of the digestible TSAA was only 80% or less. The results of this study indicated that essentially all of the digestible Lys and Met in MBM were bioavailable for protein synthesis and metabolism but suggested that a significant amount of the TSAA, particularly Cys, was not bioavailable.

  6. Comparative bioavailability studies of citric acid and malonic acid based aspirin effervescent tablets

    Directory of Open Access Journals (Sweden)

    Anju Gauniya

    2010-01-01

    Full Text Available Purpose: The present investigation is aimed at comparing the pharmacokinetic profile (Bioavailability of aspirin in tablet formulations, which were prepared by using different effervescent excipients such as citric acid and malonic acid. Materials and Methods: The relative bioavailability and pharmacokinetics of citric acid based aspirin effervescent tablet (Product A and malonic acid based aspirin effervescent tablet (Product B formulations were evaluated for an in-vitro dissolution study and in-vivo bioavailability study, in 10 normal healthy rabbits. The study utilized a randomized, crossover design with a one-week washout period between doses. Blood samples were collected at 0, 1, 2, 4, 6, 8, 12 and 24 hours following a 100 mg/kg dose. Plasma samples were assayed by High Performance Liquid Chromatography. T max , C max , AUC 0-24 , AUC 0- ∞, MRT, K a, and relative bioavailability were estimated using the traditional pharmacokinetic methods and were compared by using the paired t-test. Result: In the present study, Products A and B showed their T max , C max , AUC 0-24 , AUC 0- ∞, MRT, and K a values as 2.5 h, 2589 ± 54.79 ng/ml, 9623 ± 112.87 ng.h/ml, 9586 ± 126.22 ng.h/ml, 3.6 ± 0.10 h, and 0.3698 ± 0.003 h -1 for Product A and 3.0 h, 2054 ± 55.79 ng/ml, 9637 ± 132.87 ng.h/ml, 9870 ± 129.22 ng.h/ml, 4.76 ± 0.10 h, and 0.3812 ± 0.002 h -1 for Product B, respectively. Conclusion: The results of the paired t-test of pharmacokinetics data showed that there was no significant difference between Products A and B. From both the in vitro dissolution studies and in vivo bioavailability studies it was concluded that products A and B had similar bioavailability.

  7. Novel electrosprayed nanospherules for enhanced aqueous solubility and oral bioavailability of poorly water-soluble fenofibrate

    Directory of Open Access Journals (Sweden)

    Yousaf AM

    2016-01-01

    Full Text Available Abid Mehmood Yousaf,1,2 Omer Mustapha,1 Dong Wuk Kim,1 Dong Shik Kim,1 Kyeong Soo Kim,1 Sung Giu Jin,1 Chul Soon Yong,3 Yu Seok Youn,4 Yu-Kyoung Oh,5 Jong Oh Kim,3 Han-Gon Choi1 1College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi, South Korea; 2Faculty of Pharmacy, University of Central Punjab, Johar, Lahore, Pakistan; 3College of Pharmacy, Yeungnam University, Gyongsan, North Gyeongsang, 4School of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi, 5College of Pharmacy, Seoul National University, Seoul, South Korea Purpose: The purpose of the present research was to develop a novel electrosprayed nanospherule providing the most optimized aqueous solubility and oral bioavailability for poorly water-soluble fenofibrate.Methods: Numerous fenofibrate-loaded electrosprayed nanospherules were prepared with polyvinylpyrrolidone (PVP and Labrafil® M 2125 as carriers using the electrospray technique, and the effect of the carriers on drug solubility and solvation was assessed. The solid state characterization of an optimized formulation was conducted by scanning electron microscopy, powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopic analyses. Oral bioavailability in rats was also evaluated for the formulation of an optimized nanospherule in comparison with free drug and a conventional fenofibrate-loaded solid dispersion.Results: All of the electrosprayed nanospherule formulations had remarkably enhanced aqueous solubility and dissolution compared with free drug. Moreover, Labrafil M 2125, a surfactant, had a positive influence on the solubility and dissolution of the drug in the electrosprayed nanospherule. Increases were observed as the PVP/drug ratio increased to 4:1, but higher ratios gave no significant increases. In particular, an electrosprayed nanospherule composed of fenofibrate, PVP, and Labrafil M 2125 at the weight ratio of 1

  8. Supramolecular Complexation of Carbohydrates for the Bioavailability Enhancement of Poorly Soluble Drugs.

    Science.gov (United States)

    Cho, Eunae; Jung, Seunho

    2015-10-27

    In this review, a comprehensive overview of advances in the supramolecular complexes of carbohydrates and poorly soluble drugs is presented. Through the complexation process, poorly soluble drugs could be efficiently delivered to their desired destinations. Carbohydrates, the most abundant biomolecules, have diverse physicochemical properties owing to their inherent three-dimensional structures, hydrogen bonding, and molecular recognition abilities. In this regard, oligosaccharides and their derivatives have been utilized for the bioavailability enhancement of hydrophobic drugs via increasing the solubility or stability. By extension, polysaccharides and their derivatives can form self-assembled architectures with poorly soluble drugs and have shown increased bioavailability in terms of the sustained or controlled drug release. These supramolecular systems using carbohydrate will be developed consistently in the field of pharmaceutical and medical application.

  9. Study on the Pharmacokinetics and Relative Bioavailability of Irbesartan Capsul es in Heal thy Volunteers

    Institute of Scientific and Technical Information of China (English)

    顾世芬; 陈汇; 邱应海; 师少军; 曾繁典

    2002-01-01

    The pharmacokinetics and relative bioavailability were studied in 18 healthy volunteers. A single oral dose of 150 mg irbesartan capsule (test) or tablet (reference) was given to each volunteer according to a randomized 2-way crossover study. The concentrations in plasma were determined by HPLC-UV method. The main parameters of irbesartan capsules were: Cmax: 1. 502± 0. 295 μg/ml,tmax: 1. 44±0. 34 h, t1/2: 20. 21±14. 71 h, AUC0-t: 11. 087t3.443 μg/ml-1·h. The relative bioavailability of capsule to tablet was (101.4±28.9) %. The results of statistical analysis showed that two formulations were hioequivalent.

  10. Influence of organic matter transformations on the bioavailability of heavy metals in a sludge base compost

    Energy Technology Data Exchange (ETDEWEB)

    Molina, M. J.; Ingelmo, F.; Soriano, M. D.; Gallardo, A.; Lapena, L.

    2009-07-01

    The agricultural use of anaerobically digested sewage sludge (ADSS) as stable, mature compost implies knowing its total content in heavy metals and their bioavailability. since the chemical form of the metal in the sewage sludge-based compost depends on the effect of stabilization and maturation of the organic material during composting, the objective of this work was to examine the relationships between the changes in the organic matter content and humus fractions, and the bioavailability of heavy metals in a mixture of ADSS and wood chips (70:30 on wet basis) with an initial C/N ratio of 30.4, during its aerobic batch composting at 30 degree centigrade of external temperature in an open type lab-scale reactor with-out lixiviation. (Author)

  11. Recent Trends of Phytosomes for Delivering Herbal Extract with Improved Bioavailability

    Directory of Open Access Journals (Sweden)

    Arijit Gandhi

    2012-11-01

    Full Text Available In the recent days, most of the prevailing diseases and nutritional disorders are treated with natural medicines. The effectiveness of any herbal medication is dependent on the delivery of effective level of the therapeutically active compound. But a severe limitation exists in their bioavailability when administered orally or by topical applications. Phytosomes are recently introduced herbal formulations that are better absorbed and as a result produced better bioavailability and actions than the conventional phyto molecules or botanical extracts. Phytosomes are produced by a process whereby the standardized plant extract or its constituents are bound to phospholipids, mainly phosphatidylcholine producing a lipid compatible molecular complex. Phytosome exhibit better pharmacokinetic and pharmacodynamic profile than conventional herbal extracts. The present review represents the recent advancesand applications of various standardized herbal extract phytosomes as a tool of drug delivery.

  12. Effect of Tamarindus indica. L on the bioavailability of ibuprofen in healthy human volunteers.

    Science.gov (United States)

    Garba, M; Yakasai, I A; Bakare, M T; Munir, H Y

    2003-01-01

    The influence of Tamarindus indica L fruit extract incorporated in a traditional meal on the bioavailability of Ibuprofen tablets 400 mg dose when given concurrently was studied in 6 healthy human volunteers. There was a statistically significant increase in the plasma levels of Ibuprofen and its metabolites hydroxy-ibuprofen and carboxy-ibuprofen respectively, when the meal containing Tamarindus indica fruit extract was administered with the ibuprofen tablets than when taken under fasting state or with the meal without the fruit extract. The C(max), AUC(0-6 hr) and Ka for ibuprofen increased from 38 +/- 0.70 microg/ml to 42 +/- 0.98 microg/ml (p > 0.05); and 28.03 +/- 2.40 microg/ml x hr to 56.51 +/- 0.16 microg/ml x hr (p Tamarindus indica L. fruit extract significantly increased the bioavailability of Ibuprofen.

  13. Effect of Tamarindus indica L. on the bioavailability of aspirin in healthy human volunteers.

    Science.gov (United States)

    Mustapha, A; Yakasai, I A; Aguye, I A

    1996-01-01

    The influence of Tamarindus indica L. fruit extract incorporated in a traditional meal on the bioavailability of aspirin tablets 600 mg dose was studied in 6 healthy volunteers. There was a statistically significant increase in the plasma levels of aspirin and salicylic acid, respectively, when the meal containing Tamarindus indica fruit extract was administered with the aspirin tablets than when taken under fasting state or with the meal without the fruit extract. The Cmax, AUC0-6h and t1/2 for aspirin increased from 10.04 +/- 0.1 mg/ml to 28.62 +/- 0.21 mg/ml (P Tamarindus indica L. fruit extract significantly increased the bioavailability of aspirin.

  14. Comparative bioavailability of a morphine suppository given rectally and in a colostomy

    DEFF Research Database (Denmark)

    Højsted, J; Rubeck-Petersen, K; Rask, H;

    1990-01-01

    In eight patients with a colostomy, plasma morphine levels were followed for 8 h after administration of 20 mg morphine chloride as a suppository, first rectally and after at least 48 h via the colostomy. The bioavailability after administration in the colostomy showed very great variation......; the mean value compared to rectal bioavailability was only 43% (range 0.1-127%). In four patients the plasma concentrations of morphine after colostomy administration were lower at all times than after rectal administration, and in three only small amounts of morphine were detectable. One patient showed...... higher plasma concentrations after colostomy application than after rectal administration. It is concluded that administration of morphine suppositories in a colostomy cannot be recommended....

  15. Bioavailability of copper bound to dietary fiber in mice and rats

    Energy Technology Data Exchange (ETDEWEB)

    Rockway, S.W.; Brannon, P.M.; Weber, C.W.

    The bioavailability of copper (Cu) was compared in mice or rats fed diets containing wheat bran-bound Cu and adequate Cu (unbound) or deficient Cu with cellulose or wheat bran. Cardiac and hepatic Cu content were comparable in mice fed bran-bound or adequate Cu and greater than mice fed deficient Cu. Cardiac Cu content was comparable in rats fed bran-bound Cu and adequate Cu and greater than rats fed deficient Cu. Hepatic Cu content, however, was less in rats fed bran-bound Cu than adequate Cu and greater in both than deficient Cu. Both rats and mice utilized dietary Cu bound to wheat bran, suggesting that mineral-fiber interactions may not decrease bioavailability when dietary mineral is adequate. Tissue Cu content in Cu-deficiency was lower in animals fed wheat bran compared to cellulose, suggesting that the type of fiber may exacerbate effects of mineral deficiency.

  16. Effect of simultaneous consumption of milk and coffee on chlorogenic acids' bioavailability in humans.

    Science.gov (United States)

    Duarte, Giselle S; Farah, Adriana

    2011-07-27

    Different studies have shown that milk may interact with polyphenols and affect their bioavailability in humans. The present study investigated the effect of the simultaneous consumption of coffee and milk on the urinary excretion of chlorogenic acids (CGA) and metabolites. Subjects were submitted to consumption of water, instant coffee (609 mmol of CGA) dissolved in water, and instant coffee dissolved in whole milk. Urine was collected for 24 h after consumption of each treatment for analysis of CGA and metabolites by HPLC/LC-MS. The amount of CGA and metabolites recovered after consumption of combined coffee-milk (40% ± 27%) was consistently lower in all subjects compared to that of coffee alone (68% ± 20%). Concluding, the simultaneous consumption of milk and coffee may impair the bioavailability of coffee CGA in humans.

  17. Bioavailability is improved by enzymatic modification of the citrus flavonoid hesperidin in humans

    DEFF Research Database (Denmark)

    Nielsen, Inge Lise F; Chee, Winnie S S; Poulsen, Lea

    2006-01-01

    Hesperidin is the predominant polyphenol consumed from citrus fruits and juices. However, hesperidin is proposed to have limited bioavailability due to the rutinoside moiety attached to the flavonoid. The aim of this study was to demonstrate in human subjects that the removal of the rhamnose group...... to yield the corresponding flavonoid glucoside (i.e., hesperetin-7-glucoside) will improve the bioavailability of the aglycone hesperetin. Healthy volunteers (n=16) completed the double-blind, randomized, crossover study. Subjects randomly consumed hesperetin equivalents supplied as orange juice...... with natural hesperidin ("low dose"), orange juice treated with hesperidinase enzyme to yield hesperetin-7-glucoside, and orange juice fortified to obtain 3 times more hesperidin than naturally present ("high dose"). The area under the curve (AUC) for total plasma hesperetin of subjects consuming hesperetin-7...

  18. [Study on dosage form design for improving oral bioavailability of traditional Chinese medicines].

    Science.gov (United States)

    Xia, Hai-Jian; Zhang, Zhen-Hai; Yao, Dong-Dong; Jia, Xiao-Bin

    2013-09-01

    Both chemical drugs and traditional Chinese medicines have the problem of low bioavailability. However, as traditional Chinese medicines are a multi-component complex, their dosage forms are required to be designed in line with their characteristics, in order to improve the bioavailability of traditional Chinese medicines. Traditional Chinese medicines are mostly prepared into pill, powder, paste, elixir and decoction, but with such drawbacks as high administration dose and poor efficacy. With the process of modernization of traditional Chinese medicines, new-type preparations have be developed and made outstanding achievements. However, they fail to make an organic integration between traditional Chinese medicine theories and modern preparation theories. Characteristics of traditional Chinese medicines are required to be taken into account during the development of traditional Chinese medicines. In the article, multi-component preparation technology was adopted to establish a multi-component drug release system of traditional Chinese medicines on the basis of multiple components of traditional Chinese medicines.

  19. Volunteer stratification is more relevant than technological treatment in orange juice flavanone bioavailability.

    Science.gov (United States)

    Tomás-Navarro, María; Vallejo, Fernando; Sentandreu, Enrique; Navarro, Jose L; Tomás-Barberán, Francisco A

    2014-01-01

    The effect of two technological treatments on orange juice flavanone bioavailability in humans was assessed. Processing affected flavanone solubility and particle size of the cloud. Volunteers were stratified in high, medium, and low urinary excretion capabilities. Flavanones from high-pressure homogenized juice showed better absorption than those of conventional pasteurized juice in high excretors. These differences were not observed in medium and low excretors. High flavanone excretors took advantage of the high-pressure homogenization juice attributes (smaller cloud particle size) and showed an improved absorption/excretion. Stratification of the individuals by their excretion capability is more relevant than technological treatments in terms of flavanone bioavailability. This stratification should be considered in clinical studies with citrus juices and extracts as it could explain the large interindividual variability that is often observed.

  20. Estrogenic activity of flavonoids in mice. The importance of estrogen receptor distribution, metabolism and bioavailability

    DEFF Research Database (Denmark)

    Breinholt, Vibeke; Hossaini, A.; Svendsen, Gitte W.

    2000-01-01

    to subsequently encountered estrogens. Oral administration of equol, genistein, biochanin A and daidzein to 6-week-old female mice revealed a great variation in their systemic bioavailability. The urinary recovery of equol was thus over 90% of a single gavage administered dose, whereas the urinary recoveries...... of biochanin A, genistein and daidzein were 16, 11 and 3%, respectively. Most of the metabolites were either hydroxylated or dehydrogenated forms of the parent compounds. The in vitro estrogenic potency of some of the metabolites was greater than that of the parent compounds, whereas others were of similar...... or lower potency. Bioavailability, metabolism, the ability to alter ER alpha distribution in the uterus and the estrogenic potential of parent compound and metabolites may thus contribute to the differences in in vivo estrogenicity of dietary flavonoids....

  1. Biochar Preparation, Characterization, and Adsorptive Capacity and Its Effect on Bioavailability of Contaminants: An Overview

    Directory of Open Access Journals (Sweden)

    Obemah D. Nartey

    2014-01-01

    Full Text Available This paper provides an updated review on the subjects, the available alternative to produce biochar from biomass, quantification and characterization of biochar, the adsorptive capacity for the adsorption of contaminants, and the effect of biochar addition to agricultural soils on contaminant bioavailability. The property of biochar produced is much dependent upon the composition and type of biomass and the conditions at which biomass is carbonized. The physical and chemical characterizations are necessary to identify the basic structure and property of biochar and to predict its potential in various environmental application. Biochar is a promising alternative to remedy the soils contaminated with heavy metals and organic compounds through adsorption and immobilization due to its large surface area, charged surface, and functional groups. Overall, the bioavailability of heavy metals and organic compounds decreases when biochar is amended into soils.

  2. A Review on Phytosome Technology as a Novel Approach to Improve The Bioavailability of Nutraceuticals

    Science.gov (United States)

    Amin, Tawheed; Bhat, Suman Vikas

    2012-08-01

    The bioavailability and absorption of water soluble phytoconstituents is erratic due to poor solubility of these constituents in gastrointestinal tract. This can be overcome by a novel delivery system known as phytosome technology in which water soluble phytoconstituents are allowed to react with phospholipids. For better and improved bioavailability, natural phytoconstituents must have a good balance between hydrophilicity (helps in dissolution in gastro-intestinal fluids) and hydrophobicity (helps to cross lipid rich cell membranes). This is achieved through phytosome technology. Phospholipids have a dual solubility and acts as an emulsifier. Phytosome technology acts as a bridge between novel and conventional delivery systems. Many products are available in the market based on this phytosome technology which include popular herbal extracts such as Ginkgo biloba, Silybum marianum, grape seed, olive oil flavonoids etc.

  3. The study of lead content distribution in Chinese seafood and its oral bioavailability in mice.

    Science.gov (United States)

    Tong, Yongpeng; Zhu, Zhipeng; Hao, Xin; He, Long; He, Weibiao; Chen, Jianmin

    2016-01-01

    Using inductively coupled plasma mass spectrometry (ICP-MS), the lead concentrations and isotope ratios of 32 kinds of seafood collected from local markets of China were measured. Among these seafoods, the highest concentrations of lead were found in Patinopecten yessoensis and Mugil cephalus, which were 2.94 ± 0.40 and 2.02 ± 0.26 μg g(-1) of dry weight, respectively. Pb concentration was found to be higher in benthic fish than in other fish. The result indicated that lead concentrations in some seafood exceeded the maximum levels of Pb in foods proposed by European Commission (EC). Nine species of cooked seafood were chosen to feed mice (35-38 g). The result showed that Pb oral bioavailability of cooked seafood in vivo was below 10%. Furthermore, oral bioavailability of the same lead-containing seafood increased greatly in pregnant mice compared with non-pregnant mice.

  4. Ageing of atrazine in manure amended soils assessed by bioavailability to Pseudomonas sp. strain ADP

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Bælum, Jacob; Strobel, Bjarne W.;

    2014-01-01

    bacteria Pseudomonas sp. strain ADP. Throughout an ageing period of 90 days bioavailability was investigated at days 1, 10, 32, 60 and 90, where ~108 cells g−1 of the ADP strain was inoculated to the 14C-atrazine exposed soil and 14CO2 was collected over 7 days as a measure of mineralized atrazine. Even...... though the bioavailable residue decreased in all of the three soils as time proceeded, we found that ageing occurred faster in the topsoils rich in organic carbon than in subsoil. For one topsoil rich in organic carbon content, Simmelkær, we observed a higher degree of ageing when treated with manure....... Contrarily, sorption experiments showed less sorption to Simmelkær treated with manure than the untreated soil indicating that sorption processes are not the only mechanisms of ageing. The other topsoil low in organic carbon content, Ringe, showed no significant difference in ageing between the manure...

  5. Modelling chelate-Induced phytoextraction: functional models predicting bioavailability of metals in soil, metal uptake and shoot biomass

    Directory of Open Access Journals (Sweden)

    Pasqualina Sacco

    Full Text Available Chelate-induced phytoextraction of heavy metals from contaminated soils requires special care to determine, a priori, the best method of chelate application, in terms of both dose and timing. In fact, the chelate dose must assure the bioavailability of the metal to the plant without increasing leaching risk and giving toxic effects. Three mathematical models are here proposed for usefully interpreting the processes taking place: a increased soil bioavailability of metals by chelants; b metal uptake by plants; c variation in plant biomass. The models are implemented and validated using data from pot and lysimeter trials. Both the chelate dose and the time elapsed since its application affected metal bioavailability and plant response. Contrariwise, the distribution strategy (single vs. split application seems to produce significant differences both in plant growth and metal uptake, but not in soil metal bioavailability. The proposed models may help to understand and predict the chelate dose – effect relationship with less experimental work.

  6. Enhanced bioavailability of orally administered flurbiprofen by combined use of hydroxypropyl-cyclodextrin and poly(alkyl-cyanoacrylate) nanoparticles.

    Science.gov (United States)

    Zhao, Xiaoyun; Li, Wei; Luo, Qiuhua; Zhang, Xiangrong

    2014-03-01

    Flurbiprofen was formulated into nanoparticle suspension to improve its oral bioavailability. Hydroxypropyl-β-cyclodextrin inclusion-flurbiprofen complex (HP-β-CD-FP) was prepared, then incorporating this complex into poly(alkyl-cyanoacrylate) (PACA) nanoparticles. HP-β-CD-FP-PACA nanoparticle was prepared by the emulsion solvent polymerization method. The zeta potential was -26.8 mV, the mean volume particle diameter was 134 nm, drug encapsulation efficiency was 53.3 ± 3.6 % and concentration was 1.5 mg/mL. The bioavailability of flurbiprofen from optimized nanoparticles was assessed in male Wistar rats at a dose of 15 mg/kg. As compared to the flurbiprofen suspension, 211.6 % relative bioavailability was observed for flurbiprofen nanoparticles. The reduced particle size and increased surface area may contribute to improve oral bioavailability of flurbiprofen.

  7. In vivo measurement, in vitro estimation and fugacity prediction of PAH bioavailability in post-remediated creosote-contaminated soil.

    Science.gov (United States)

    Juhasz, Albert L; Weber, John; Stevenson, Gavin; Slee, Daniel; Gancarz, Dorota; Rofe, Allan; Smith, Euan

    2014-03-01

    In this study, PAH bioavailability was assessed in creosote-contaminated soil following bioremediation in order to determine potential human health exposure to residual PAHs from incidental soil ingestion. Following 1,000 days of enhanced natural attenuation (ENA), a residual PAH concentration of 871 ± 8 mg kg(-1) (∑16 USEPA priority PAHs in the PAH absolute bioavailability were in excess of 65% irrespective of the molecular weight of the PAH. These results indicate that a significant proportion of the residual PAH fraction following ENA may be available for absorption following soil ingestion. In contrast, when PAH bioavailability was estimated/predicted using an in vitro surrogate assay (FOREhST assay) and fugacity modelling, PAH bioavailability was up to 2000 times lower compared to measured in vivo values depending on the methodology used.

  8. Toxicokinetics/toxicodynamics links bioavailability for assessing arsenic uptake and toxicity in three aquaculture species.

    Science.gov (United States)

    Chen, Wei-Yu; Liao, Chung-Min

    2012-11-01

    The purpose of this study was to link toxicokinetics/toxicodynamics (TK/TD) and bioavailability-based metal uptake kinetics to assess arsenic (As) uptake and bioaccumulation in three common farmed species of tilapia (Oreochromis mossambicus), milkfish (Chanos chanos), and freshwater clam (Corbicula fluminea). We developed a mechanistic framework by linking damage assessment model (DAM) and bioavailability-based Michaelis-Menten model for describing TK/TD and As uptake mechanisms. The proposed model was verified with published acute toxicity data. The estimated TK/TD parameters were used to simulate the relationship between bioavailable As uptake and susceptibility probability. The As toxicity was also evaluated based on a constructed elimination-recovery scheme. Absorption rate constants were estimated to be 0.025, 0.016, and 0.175 mL g(-1) h(-1) and As uptake rate constant estimates were 22.875, 63.125, and 788.318 ng g(-1) h(-1) for tilapia, milkfish, and freshwater clam, respectively. Here we showed that a potential trade-off between capacities of As elimination and damage recovery was found among three farmed species. Moreover, the susceptibility probability can also be estimated by the elimination-recovery relations. This study suggested that bioavailability-based uptake kinetics and TK/TD-based DAM could be integrated for assessing metal uptake and toxicity in aquatic organisms. This study is useful to quantitatively assess the complex environmental behavior of metal uptake and implicate to risk assessment of metals in aquaculture systems.

  9. [Relative bioavailability of glucosamine after oral, intramuscular and transdermal administration of hondroxid maximum preparation in experiment].

    Science.gov (United States)

    Yasso, B; Li, Y; Alexander, A; Mel'nikova, N B; Mukhina, I V

    2014-01-01

    A comparison of the relative bioavailability and intensity of penetration of glucosamine sulfate in oral, injection and topical administration of the dosage form Hondroxid Maximum as a cream containing micellar system for transdermal delivery of glucosamine in the experiment by Sprague-Dawley rats was carried out. On the base on the pharmacokinetic profiles data of glucosamine in rat blood plasma with daily administration in 3 times a day for 1 week by cream Hondroxid Maximum 400 mg/kg and the single injection solution of 4% Glucosamine sulfate 400 mg/kg was found that the relative bioavailability was 61.6%. Calculated penetration rate of glucosamine in the plasma through the rats skin in 4 hours, equal to 26.9 μg/cm2 x h, and the penetration of glucosamine through the skin into the plasma after a single dose of cream in 4 hours was 4.12%. Comparative analysis of literature and experimental data and calculations based on them suggest that medicine Hondroxid Maximum, cream with transdermal glucosamine complex in the treatment in accordance with the instructions can provide an average concentration of glucosamine in the synovial fluid of an inflamed joint in the range (0.7 - 1.5) μg/ml, much higher than the concentration of endogenous glucosamine human synovial joint fluid (0.02 - 0.07 μg/ml). By theoretical calculations taking into account experimental data it is shown that the medicine Hondroxid Maximum can reach the bioavailability level of the modern injection forms and exceed the bioavailability level of modern oral forms of glucosamine up to 2 times.

  10. Formulation of a danazol cocrystal with controlled supersaturation plays an essential role in improving bioavailability.

    Science.gov (United States)

    Childs, Scott L; Kandi, Praveen; Lingireddy, Sreenivas Reddy

    2013-08-05

    Cocrystals have become an established and adopted approach for creating crystalline solids with improved physical properties, but incorporating cocrystals into enabling pre-clinical formulations suitable for animal dosing has received limited attention. The dominant approach to in vivo evaluation of cocrystals has focused on deliberately excluding additional formulation in favor of "neat" aqueous suspensions of cocrystals or loading neat cocrystal material into capsules. However, this study demonstrates that, in order to take advantage of the improved solubility of a 1:1 danazol:vanillin cocrystal, a suitable formulation was required. The neat aqueous suspension of the danazol:vanillin cocrystal had a modest in vivo improvement of 1.7 times higher area under the curve compared to the poorly soluble crystal form of danazol dosed under identical conditions, but the formulated aqueous suspension containing 1% vitamin E-TPGS (TPGS) and 2% Klucel LF Pharm hydroxypropylcellulose improved the bioavailability of the cocrystal by over 10 times compared to the poorly soluble danazol polymorph. In vitro powder dissolution data obtained under non-sink biorelevant conditions correlate with in vivo data in rats following 20 mg/kg doses of danazol. In the case of the danazol:vanillin cocrystal, using a combination of cocrystal, solubilizer, and precipitation inhibitor in a designed supersaturating drug delivery system resulted in a dramatic improvement in the bioavailability. When suspensions of neat cocrystal material fail to return the anticipated bioavailability increase, a supersaturating formulation may be able to create the conditions required for the increased cocrystal solubility to be translated into improved in vivo absorption at levels competitive with existing formulation approaches used to overcome solubility limited bioavailability.

  11. Lower zinc bioavailability may be related to higher risk of subclinical atherosclerosis in Korean adults.

    Directory of Open Access Journals (Sweden)

    Su Kyoung Jung

    Full Text Available BACKGROUND: There is a proposed link between dietary zinc intake and atherosclerosis, but this relationship remains unclear. Phytate may contribute to this relationship by influencing zinc bioavailability. OBJECTIVE: The aim of this study is to examine the relationship between zinc bioavailability and subclinical atherosclerosis in healthy Korean adults. MATERIALS AND METHODS: The present cross-sectional analysis used baseline data from the Korean multi-Rural Communities Cohort Study (MRCohort, which is a part of The Korean Genome Epidemiology Study (KoGES. A total of 5,532 subjects (2,116 men and 3,416 women aged 40 years and older were recruited from rural communities in South Korea between 2005 and 2010. Phytate:zinc molar ratio, estimated from a food-based food frequency questionnaire (FFQ of 106 food items, was used to determine zinc bioavailability, and carotid intima media thickness (cIMT and pulse wave velocity (PWV were measured to calculate the subclinical atherosclerotic index. RESULTS: We found that phytate:zinc molar ratio is positively related to cIMT in men. A higher phytate:zinc molar ratio was significantly related to an increased risk of atherosclerosis in men, defined as the 80(th percentile value of cIMT (5(th vs. 1(st quintile, OR = 2.11, 95% CI 1.42-3.15, P for trend = 0.0009, and especially in elderly men (5(th vs. 1(st quintile, OR = 2.58, 95% CI 1.52-4.37, P for trend = 0.0021. We found a positive relationship between phytate:zinc molar ratio and atherosclerosis risk among women aged 65 years or younger. Phytate:zinc molar ratio was not found to be related to PWV. CONCLUSIONS: Lower zinc bioavailability may be related to higher atherosclerosis risk.

  12. Characterization and Bioavailability of Wogonin by Different Administration Routes in Beagles.

    Science.gov (United States)

    Zhu, Na; Li, Jian-Chun; Zhu, Jin-Xiu; Wang, Xiu; Zhang, Jin

    2016-10-16

    BACKGROUND With the gradually accumulating research on pharmacological activity of wogonin, the in vitro analysis research on wogonin has become more and more popular, but there are very few reports about in vivo detection, and there are no solid dispersions (SDs) of Wogonin. The aim of this study was to explore the formation of solid dispersions (SDs) of wogonin. The reasons for the low bioavailability were studied through different routes of administration. MATERIAL AND METHODS SDs was formulated using the solvent evaporation method via polyvinylpyrrolidone K30 (PVP). The characterization of the drug and its carrier was detected by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The serum concentrations of Wogonin were detected using the LC-MS/MS method. Six beagles were fed 3 different formulations of wogonin in 3 cycles. RESULTS The SDs of wogonin had a higher solubility than the physical mixtures. Based on XRD and DSC, wogonin was transformed from a crystalline morphology to an amorphous structure. The main pharmacokinetic parameters of i.g. administration (crude material and SD) and i.v. route were as follows: Cmax (2.5±1.1), (7.9±3.3), and (6838.7±1322.1) μg/L, tmax (0.7±0.3) and (0.3±0.2) h for the former, AUC0-t (7.1±2.0), (21.0±3.2) and (629.7±111.8) μg·h/L. The absolute bioavailability of native wogonin and wogonin arginine solution were (0.59±0.35)% and (3.65± 2.60)%. Further research showed that the low bioavailability of wogonin might be associated with low solubility and rapid combination with glucuronic acid in vivo. CONCLUSIONS The significantly increased solubility of SDs and the further preparation of arginine solution could significantly increase the bioavailability of wogonin.

  13. Bioavailability of the Yuzpe and levonorgestrel regimens of emergency contraception: vaginal vs. oral administration.

    Science.gov (United States)

    Kives, Sari; Hahn, Philip M; White, Emily; Stanczyk, Frank Z; Reid, Robert L

    2005-03-01

    Separate crossover studies compared the bioavailability of oral vs. vaginal routes of administration for the Yuzpe (n=5) and levonorgestrel regimens (n=4) of emergency contraception. Twice the standard dose of the Yuzpe regimen (200 microg of ethinyl estradiol, 1000 microg of levonorgestrel) or the levonorgestrel regimen (1500 microg of levonorgestrel) was self-administered vaginally. One week later, each subject received orally the standard dose of the assigned medication. Serial blood samples were collected over 24 h and assayed for levonorgestrel and ethinyl estradiol (for the Yuzpe regimen only). Paired t tests were used to compare oral vs. vaginal administration for maximum concentration (Cmax), time to maximum concentration (Tmax) and area under the curve over 24 h (AUC0-24). Relative bioavailability (vaginal/oral) was derived from AUC0-24. Vaginal administration of double the standard dose of the Yuzpe regimen resulted in a lower Cmax (vaginal=5.4 vs. oral=14.6 ng/mL, p=.038) and a later Tmax (5.9 vs. 2.0 h, p=.066) for levonorgestrel, compared to oral administration. Corresponding ethinyl estradiol concentrations were higher (786 vs. 391 pg/mL, p=.039) and peaked later (4.0 vs. 1.9 hr, p=.154) with vaginal administration. Relative bioavailabilities for levonorgestrel and ethinyl estradiol were 58% and 175%, respectively. Similarly, vaginal administration of the levonorgestrel regimen resulted in a lower Cmax (vaginal=5.4 vs. oral=15.2 ng/mL, p=.006) and a later Tmax (7.4 vs. 1.3 h, p=.037) for levonorgestel, compared to oral administration. The relative bioavailability was 62%. Our preliminary data suggest that vaginal administration of these emergency contraception regimens appears to require at least three times the standard oral dose to achieve equivalent systemic levonorgestrel concentrations.

  14. Bioavailability study of calcium sandoz-250 by atomic absorption spectroscopy in albino rats

    OpenAIRE

    Patel, Bimalkumar N.; Krishnaveni, N.; Jivani, Nurrrudin P.; Khodakiya, Akruti S.; Khodakiya, Moorti S.; Parida, Saswat K.

    2014-01-01

    Background: Calcium sandoz-250 is an Ayurvedic calcium supplement, containing Khatika Churna. Bioavailability study of the formulation is essential for estimation of peak plasma concentration (C max), time to C max and rate of absorption. Aim: To evaluate the absorption parameters of calcium sandoz-250 in albino rats by atomic absorption spectroscopic (AAS) method. Materials and Methods: Study was carried out as a single dose, open-label, randomized study. Estimation of calcium was carried ou...

  15. HCN Producing Bacteria Enable Sensing Of Non-Bioavailable Hg Species by the Whole Cell Biosensor

    Science.gov (United States)

    Horvat, M.; Rijavec, T.; Koron, N.; Lapanje, A.

    2015-12-01

    Bacteria play an important role in Hg transformation reactions. The production of cyanide (HCN) and other secondary metabolites seems to be key elements involved in these transformations. Current hypotheses link the role of HCN production to growth inhibition of nonHCN producing competitor organisms (role of an antimicrobial agent). Our past investigations showed that HCN production did not correlate with antimicrobial activity and since pK value of HCN is very high (pK = 9,21), it can be expected that most of the produced HCN is removed from the microenvironment. This way, the expected inhibitory concentrations can hardly be reached. Accordingly, we proposed a new concept, where the ability of complexation of transient metals by HCN served as a regulation process for the accessibility of micro-elements. In our study, we focused on the presence of HCN producing bacteria and carried it out in the Hg contaminated environment connected to the Idrija Mercury Mine, Slovenia. We characterised the isolates according to the presence of Hg resistance (HgR), level of HCN production and genetic similarities. In laboratory setups, using our merR whole cell based biosensor, we determined the transformation of low bioavailable Hg0 and HgS forms into bioavailable Hg by these HCN producing bacteria. We observed that HgR strains producing HCN had the highest impact on increased Hg bioavailability. In the proposed ecological strategy HgR HCN producing bacteria increase their competitive edge over non-HgR competitors through the increase of Hg toxicity. Due to their activity, Hg is made available to other organisms as well and thus enters into the ecosystem. Finally, using some of the characteristics of bacteria (e.g. Hg resistance genetic elements), we developed a fully automated sensing approach, combining biosensorics and mechatronics, to measure the bioavailability of Hg in situ.

  16. Assessment of polymorphic metabolite data in bioavailability/bioequivalence studies - considerations and challenges

    OpenAIRE

    Srinivas, Nuggehally R.

    2011-01-01

    Bioavailability (BA)/ bioequivalence (BE) studies are the cornerstone for the approval of generic drugs. While BA/BE assessment involving the pharmacokinetic data of the parent compound has been routinely performed, the introduction of the assessment of metabolite(s) data, alone or in addition to parent compound, has also emerged. In this context, the assessment of BA/BE of metabolite(s) may pose additional complexities and challenges, if the metabolic pathway is under the influence of a poly...

  17. Chronic administration of a microencapsulated probiotic enhances the bioavailability of orange juice flavanones in humans.

    Science.gov (United States)

    Pereira-Caro, Gema; Oliver, Christine M; Weerakkody, Rangika; Singh, Tanoj; Conlon, Michael; Borges, Gina; Sanguansri, Luz; Lockett, Trevor; Roberts, Susan A; Crozier, Alan; Augustin, Mary Ann

    2015-07-01

    Orange juice (OJ) flavanones are bioactive polyphenols that are absorbed principally in the large intestine. Ingestion of probiotics has been associated with favorable changes in the colonic microflora. The present study examined the acute and chronic effects of orally administered Bifidobacterium longum R0175 on the colonic microflora and bioavailability of OJ flavanones in healthy volunteers. In an acute study volunteers drank OJ with and without the microencapsulated probiotic, whereas the chronic effects were examined when OJ was consumed after daily supplementation with the probiotic over 4 weeks. Bioavailability, assessed by 0-24h urinary excretion, was similar when OJ was consumed with and without acute probiotic intake. Hesperetin-O-glucuronides, naringenin-O-glucuronides, and hesperetin-3'-O-sulfate were the main urinary flavanone metabolites. The overall urinary excretion of these metabolites after OJ ingestion and acute probiotic intake corresponded to 22% of intake, whereas excretion of key colon-derived phenolic and aromatic acids was equivalent to 21% of the ingested OJ (poly)phenols. Acute OJ consumption after chronic probiotic intake over 4 weeks resulted in the excretion of 27% of flavanone intake, and excretion of selected phenolic acids also increased significantly to 43% of (poly)phenol intake, corresponding to an overall bioavailability of 70%. Neither the probiotic bacterial profiles of stools nor the stool moisture, weight, pH, or levels of short-chain fatty acids and phenols differed significantly between treatments. These findings highlight the positive effect of chronic, but not acute, intake of microencapsulated B. longum R0175 on the bioavailability of OJ flavanones.

  18. Bioavailability of andrographolide and protection against carbon tetrachloride-induced oxidative damage in rats

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Haw-Wen [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Huang, Chin-Shiu [Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan (China); Li, Chien-Chun [School of Nutrition, Chung Shan Medical University, Taichung, Taiwan (China); Department of Nutrition, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Lin, Ai-Hsuan; Huang, Yu-Ju [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Wang, Tsu-Shing [Department of Biomedical Science, Chung Shan Medical University, Taichung, Taiwan (China); Yao, Hsien-Tsung, E-mail: htyao@mail.cmu.edu.tw [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Lii, Chong-Kuei, E-mail: cklii@mail.cmu.edu.tw [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan (China)

    2014-10-01

    Andrographolide, a bioactive diterpenoid, is identified in Andrographis paniculata. In this study, we investigated the pharmacokinetics and bioavailability of andrographolide in rats and studied whether andrographolide enhances antioxidant defense in a variety of tissues and protects against carbon tetrachloride-induced oxidative damage. After a single 50-mg/kg administration, the maximum plasma concentration of andrographolide was 1 μM which peaked at 30 min. The bioavailability of andrographolide was 1.19%. In a hepatoprotection study, rats were intragastrically dosed with 30 or 50 mg/kg andrographolide for 5 consecutive days. The results showed that andrographolide up-regulated glutamate cysteine ligase (GCL) catalytic and modifier subunits, superoxide dismutase (SOD)-1, heme oxygenase (HO)-1, and glutathione (GSH) S-transferase (GST) Ya/Yb protein and mRNA expression in the liver, heart, and kidneys. The activity of SOD, GST, and GSH reductase was also increased in rats dosed with andrographolide (p < 0.05). Immunoblot analysis and EMSA revealed that andrographolide increased nuclear Nrf2 contents and Nrf2 binding to DNA, respectively. After the 5-day andrographolide treatment, one group of animals was intraperitoneally injected with carbon tetrachloride (CCl{sub 4}) at day 6. Andrographolide pretreatment suppressed CCl{sub 4}-induced plasma aminotransferase activity and hepatic lipid peroxidation (p < 0.05). These results suggest that andrographolide is quickly absorbed in the intestinal tract in rats with a bioavailability of 1.19%. Andrographolide protects against chemical-induced oxidative damage by up-regulating the gene transcription and activity of antioxidant enzymes in various tissues. - Highlights: • The bioavailability of andrographolide is 1.19% in rats. • Plasma concentration reaches 1 μM after giving 50 mg/kg andrographolide. • Andrographolide up-regulates Nrf2-dependent antioxidant genes. • Andrographolide increases antioxidant defense

  19. PLANTEROSOMES: A POTENTIAL PHYTO-PHOSPHOLIPID CARRIERS FOR THE BIOAVAILABILITY ENHANCEMENT OF HERBAL EXTRACTS

    Directory of Open Access Journals (Sweden)

    Priyanka Rathore

    2012-03-01

    Full Text Available Planterosomes, term “PLANTERO” means plant while “SOME” means cell-like. A novel emerging technique applied to phytopharmaceutical for the enhancement of bioavailability of herbal extract for medicinal applications. Since the two major limiting factors for molecules to pass the biological membrane for their absorption in the blood stream mainly includes lipid solubility and molecular sizes. There are many plant extracts having excellent bioactivity in vitro but low or less in vivo because of their poor lipid solubility and improper size of the molecule or both which result in poor absorption and bioavailability of constituents from plant extract and are destroyed in the gastric fluids when taken orally. Planterosomes are recent advanced forms of herbal formulations that have enhanced absorption rate, producing better bioavailability than conventional herbal extracts. Since they have improved pharmacological and pharmacokinetic parameters, they can be used in the treatment of the acute and chronic liver disease. Planterosomes are prepared by non conventional methods. Planterosomes absorption in GIT is greater resulting in increased plasma level than individual component. They act as a bridge between novel delivery system and conventional delivery system. Phospholipids molecule acting as vital carrier made up of water soluble head and two fat soluble tails, due to this nature they possess dual solubility and thus acting as an effective emulsifier. These drug-phospholipids complex can be formulated in the form of solutions, suspensions, emulsions, syrup, lotion, gel, cream, aqueous microdispersions, pill, capsule, powder, granules and chewable tablets. Planterosomes just like Phytosomes technology effectively enhanced the bioavailability of many popular herbal extracts including milk thistle, Ginkgo biloba, grape seed and ginseng etc.

  20. Phenolic Esters of O-Desmethylvenlafaxine with Improved Oral Bioavailability and Brain Uptake

    OpenAIRE

    2013-01-01

    O-Desmethylvenlafaxine (desvenlafaxine, ODV) is a recently approved antidepressant which in some clinical studies failed to meet a satisfactory end-point. The aim of this study was to prepare a series of phenolic esters of ODV and evaluate their potential as ODV prodrugs with improved brain uptake. Fifteen phenolic esters (compounds 1a–o) were synthesized and their pharmacokinetic profiles evaluated in rat. The four compounds producing the highest relative bioavailability of ODV in rat (comp...

  1. Prediction of the bioavailability of minerals and trace elements in foods.

    OpenAIRE

    Wolters, M.G.E.

    1992-01-01

    Minerals and trace elements play essential roles in numerous biochemical and physiological processes in animals and man. A deficiency, an overdose or imbalances between minerals or trace elements will exert a negative effect on health. Generally, it is not the ingested dose of minerals and trace elements that is important to maintain balance, but rather the amount that is bioavailable (available for biological and biochemical processes in the organism). Several food components are able to for...

  2. Enhanced bioavailability of sirolimus via preparation of solid dispersion nanoparticles using a supercritical antisolvent process

    Directory of Open Access Journals (Sweden)

    Kim MS

    2011-11-01

    Full Text Available Min-Soo Kim1, Jeong-Soo Kim1, Hee Jun Park1, Won Kyung Cho1,3, Kwang-Ho Cha1,3, Sung-Joo Hwang2,31College of Pharmacy, Chungnam National University, Daejeon, Republic of Korea, 2College of Pharmacy, 3Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Republic of KoreaBackground: The aim of this study was to improve the physicochemical properties and bioavailability of poorly water-soluble sirolimus via preparation of a solid dispersion of nanoparticles using a supercritical antisolvent (SAS process.Methods: First, excipients for enhancing the stability and solubility of sirolimus were screened. Second, using the SAS process, solid dispersions of sirolimus-polyvinylpyrrolidone (PVP K30 nanoparticles were prepared with or without surfactants such as sodium lauryl sulfate (SLS, tocopheryl propylene glycol succinate, Sucroester 15, Gelucire 50/13, and Myrj 52. A mean particle size of approximately 250 nm was obtained for PVP K30-sirolimus nanoparticles. Solid state characterization, kinetic solubility, powder dissolution, stability, and pharmacokinetics were analyzed in rats.Results: X-ray diffraction, differential scanning calorimetry, and high-pressure liquid chromatography indicated that sirolimus existed in an anhydrous amorphous form within a solid dispersion of nanoparticles and that no degradation occurred after SAS processing. The improved supersaturation and dissolution of sirolimus as a solid dispersion of nanoparticles appeared to be well correlated with enhanced bioavailability of oral sirolimus in rats. With oral administration of a solid dispersion of PVP K30-SLS-sirolimus nanoparticles, the peak concentration and AUC0→12h of sirolimus were increased by approximately 18.3-fold and 15.2-fold, respectively.Conclusion: The results of this study suggest that preparation of PVP K30-sirolimus-surfactant nanoparticles using the SAS process may be a promising approach for improving the bioavailability of sirolimus

  3. Bioavailability studies and the clinical pharmacologist: correlation of drug distribution with clinical effects.

    Science.gov (United States)

    Ogilvie, R I

    1975-06-01

    Bioavailability studies can be interpreted only when clinical information is available which correlates drug distribution with both efficacious and toxic clinical effects. The clinical pharmacologist should be instrumental in the development of safe and effective drug therapy by the systematic application of well designed clinical trials, the clear definition of therapeutically desirable clinical responses, and the development and application of improved techniques of measuring these effects.

  4. Lac Dufault sediment core trace metal distribution, bioavailability and toxicity to Hyalella azteca

    Energy Technology Data Exchange (ETDEWEB)

    Nowierski, Monica [Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Dixon, D. George [Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Borgmann, Uwe [National Water Research Institute, Canada Centre for Inland Waters, 867 Lakeshore Road, PO Box 5050, Burlington, Ontario L7R 4A6 (Canada)]. E-mail: uwe.borgmann@ec.gc.ca

    2006-02-15

    To determine changes in metal distribution, bioavailability and toxicity with sediment depth, two 20-cm-long replicate cores were collected from a lake historically subjected to the influence of metal mining and smelting activity. The vertical distribution of Pb, Cd and Cu in sediment was similar for all three metals, with the surface layers showing enrichment and the deeper (pre-industrial) layers showing lower concentrations. Toxicity of each sediment core section was determined in laboratory tests with the freshwater amphipod Hyalella azteca. Bioavailable metal in each sediment slice was estimated from metal concentrations in overlying water in these toxicity tests and, for Cd, also from metal bioaccumulation. The profile for Cd in tissue was comparable to Cd in sediment and overlying water, but relative Cd bioavailability from sediment increased with sediment depth. Survival increased with increasing sediment depth, suggesting that surface sediments were probably less or non-toxic before industrialization. - Toxicity and bioaccumulation tests with sediment cores provide more information on biological effects of metals than surface sediment tests.

  5. Measures of bioavailable serum sex hormone levels in aging Chinese by protein chip

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yong; DU Guanhua; CHANG Shuying; MENG Xiaoluo; YU Huafeng; WANG Luning; HE Jinggui; ZHANG Baohe; ZHANG Juntian; GENG Meiyu

    2006-01-01

    The purpose of this study was to develop a protein chip technique based on receptor binding assays to measure bioavailable serum sex hormone levels (BSSHL). 224 aging healthy Chinese were investigated to get the referenced values of BSSHL for the first time. In the assays recombined sex hormone receptor proteins were jointed to polysaccharide coated slides to make protein chip, and the dose-dependence curves of sex hormone on chip were prepared. The data showed that this method had good precision (CV<16%) and accuracy (Bias<10%), and the sensitivity could reach 1 pmol/L. From the results, BSSHL of men and women declined with aging, but no significant differences were observed. The BSSHL of aging men were higher than those of women. The bioavailable serum androgen level of men was 52―112 pmol/L, women's was 3―70 pmol/L and the whole group was 41.9―81.4 pmol/L. The bioavailable serum estrogen level of men was 0.8―3.0 pmol/L, women's was 1.2―2.5 pmol/L and the whole group was 0.6―2.64 pmol/L. Based on the assays, BSSHL measurement by protein chip can meet the needs of epidemiological studies in terms of speed, accuracy and sample volume required, and was helpful in quantitative assessment of aging people's health.

  6. Facilitated Bioavailability of PAHs to Native Soil Bacteria Promoted by Nutrient Addition

    Science.gov (United States)

    Pignatello, J. J.; Li, J.

    2006-12-01

    Facilitated bioavailability refers to the ability of an organism to have access to pools of non-labile chemical. Mechanisms proposed for this ability include release of biosurfactants, direct mining of adsorbed chemical, alteration of interfacial chemistry, and passive effects of attached biofilms on molecular diffusion. We investigated the biodegradation by indigenous organisms of a set of 16 standard polycyclic aromatic hydrocarbons (PAHs) in coal tar contaminated soil from a manufactured gas plant site in Connecticut in well- mixed aerobic reactors containing various additives over a 93-106 day period. Parallel desorption experiments were conducted in the presence of a biocide and an excess of Tenax-TA adsorbent beads to simulate desorption to infinite dilution (i.e., maximal concentration gradient for diffusion). Both biotransformation and desorption decreased with PAH ring size, as expected. Biodegradation by native organisms was strongly accelerated by addition of inorganic nutrients (N, P, K, and trace metals). In the absence of added nutrients, the biodegradation resistant fraction correlated well with the desorption resistant fraction. However, in the presence of added nutrients, the extent of biodegradation was greater than the extent of desorption except for the largest compounds, which neither degraded nor desorbed. The ability of nutrients to accelerate degradation of bioavailable PAHs by native cells indicates that the persistence of PAHs for many decades at this site is likely due to nutrient-limited natural attenuation. The surprising result of this study is that application of nutrients promotes `facilitated bioavailability' of PAHs in this soil to indigenous microorganisms.

  7. Ageing of atrazine in manure amended soils assessed by bioavailability to Pseudomonas sp. strain ADP.

    Science.gov (United States)

    Glæsner, Nadia; Bælum, Jacob; Strobel, Bjarne W; Jacobsen, Carsten S

    2014-04-01

    Animal manure is applied to agricultural land in areas of high livestock production. In the present study, we evaluated ageing of atrazine in two topsoils with and without addition of manure and in one subsoil. Ageing was assessed as the bioavailability of atrazine to the atrazine mineralizing bacteria Pseudomonas sp. strain ADP. Throughout an ageing period of 90 days bioavailability was investigated at days 1, 10, 32, 60 and 90, where ~10(8) cells g(-1) of the ADP strain was inoculated to the (14)C-atrazine exposed soil and (14)CO2 was collected over 7 days as a measure of mineralized atrazine. Even though the bioavailable residue decreased in all of the three soils as time proceeded, we found that ageing occurred faster in the topsoils rich in organic carbon than in subsoil. For one topsoil rich in organic carbon content, Simmelkær, we observed a higher degree of ageing when treated with manure. Contrarily, sorption experiments showed less sorption to Simmelkær treated with manure than the untreated soil indicating that sorption processes are not the only mechanisms of ageing. The other topsoil low in organic carbon content, Ringe, showed no significant difference in ageing between the manure-treated and untreated soil. The present study illustrates that not simply the organic carbon content influences adsorption and ageing of atrazine in soil but the origin and composition of organic matter plays an important role.

  8. Absolute and comparative subcutaneous bioavailability of ardeparin sodium, a low molecular weight heparin.

    Science.gov (United States)

    Troy, S; Fruncillo, R; Ozawa, T; Mammen, E; Holloway, S; Chiang, S

    1997-08-01

    Ardeparin sodium (Normiflo, Wyeth-Ayerst) is a low molecular weight heparin undergoing clinical evaluation as an antithrombotic agent. The objective of this study was to evaluate the absolute and comparative bioavailability of ardeparin following subcutaneous administration of three different formulations [two formulations of ardeparin at 10,000 anti-factor Xa (aXa) U/ml, but with different preservatives, and a 20,000 aXa U/ml formulation]. The study was conducted using a randomized 4-period crossover design (three subcutaneous treatments and one intravenous treatment) in 24 healthy subjects, and the pharmacokinetics of ardeparin were characterized by plasma anti-factor IIa (aIIa) and anti-factor Xa (aXa) activities. The mean absolute bioavailability of ardeparin based on aIIa activity ranged from 62% to 64% and the mean absolute bioavailability based on aXa activity ranged from 88% to 97%. Based on bioequivalence testing criteria, the three ardeparin formulations were bioequivalent.

  9. Enhanced oral bioavailability and in vivo antioxidant activity of chlorogenic acid via liposomal formulation.

    Science.gov (United States)

    Feng, Yingshu; Sun, Congyong; Yuan, Yangyang; Zhu, Yuan; Wan, Jinyi; Firempong, Caleb Kesse; Omari-Siaw, Emmanuel; Xu, Yang; Pu, Zunqin; Yu, Jiangnan; Xu, Ximing

    2016-03-30

    In the present study, a formulation system consisting of cholesterol and phosphatidyl choline was used to prepare an effective chlorogenic acid-loaded liposome (CAL) with an improved oral bioavailability and an increased antioxidant activity. The developed liposomal formulation produced regular, spherical and multilamellar-shaped distribution nanoparticles. The pharmacokinetic analysis of CAL compared with chlorogenic acid (CA), showed a higher value of Cmax(6.42 ± 1.49 min versus 3.97 ± 0.39 min) and a delayed Tmax(15 min versus 10 min), with 1.29-fold increase in relative oral bioavailability. The tissue distribution in mice also demonstrated that CAL predominantly accumulated in the liver which indicated hepatic targeting potential of the drug. The increased activities of antioxidant enzymes (Total Superoxide Dismutase (T-SOD) and Glutathione Peroxidase (GSH-Px)) and total antioxidant capacity (T-AOC), in addition to decreased level of malondialdehyde (MDA) in CCl4-induced hepatotoxicity study further revealed that CAL exhibited significant hepatoprotective and antioxidant effects. Collectively, these findings present a liposomal formulation with significantly improved oral bioavailability and an increased in vivo antioxidant activity of CA.

  10. Food macromolecule based nanodelivery systems for enhancing the bioavailability of polyphenols

    Directory of Open Access Journals (Sweden)

    Bing Hu

    2017-01-01

    Full Text Available Diet polyphenols—primarily categorized into flavonoids (e.g., flavonols, flavones, flavan-3-ols, anthocyanidins, flavanones, and isoflavones and nonflavonoids (with major subclasses of stilbenes and phenolic acids—are reported to have health-promoting effects, such as antioxidant, antiinflammatory, anticarcinoma, antimicrobial, antiviral, and cardioprotective properties. However, their applications in functional foods or medicine are limited because of their inefficient systemic delivery and poor oral bioavailability. Epigallocatechin-3-gallate, curcumin, and resveratrol are the well-known representatives of the bioactive diet polyphenols but with poor bioavailability. Food macromolecule based nanoparticles have been fabricated using reassembled proteins, crosslinked polysaccharides, protein–polysaccharide conjugates (complexes, as well as emulsified lipid via safe procedures that could be applied in food. The human gastrointestinal digestion tract is the first place where the food grade macromolecule nanoparticles exert their effects on improving the bioavailability of diet polyphenols, via enhancing their solubility, preventing their degradation in the intestinal environment, elevating the permeation in small intestine, and even increasing their contents in the bloodstream. We contend that the stability and structure behaviors of nanocarriers in the gastrointestinal tract environment and the effects of nanoencapsulation on the metabolism of polyphenols warrant more focused attention in further studies.

  11. In vitro bioavailability of phenolic compounds from five cultivars of frozen sweet cherries (Prunus avium L.).

    Science.gov (United States)

    Fazzari, Marco; Fukumoto, Lana; Mazza, Giuseppe; Livrea, Maria A; Tesoriere, Luisa; Marco, Luigi Di

    2008-05-28

    The bioavailability of phenolic compounds from five cultivars of frozen sweet cherries was assessed by a digestion process involving pepsin-HCl digestion (to simulate gastric digestion) and pancreatin digestion with bile salts (to simulate small intestine conditions) and dialyzed to assess serum- and colon-available fractions. After pepsin digestion, the % recovery of total phenolics, relative to the original starting material, increased, whereas the % anthocyanins did not change. Following pancreatic digestion and dialysis, the total phenolics in the IN (serum-available) fraction was about 26-30% and the OUT (colon-available) fraction was about 77-101%. The anthocyanin content in the IN fraction was 15-21%, and in the OUT fraction, it was 52-67%. Skeena, Lapins, and Sweetheart cultivars contained higher levels of total phenolics and anthocyanins, which resulted in higher concentrations of these compounds in the IN and OUT fractions. The potential bioavailability of phenolic compounds was also assessed in Bing and Lapins cultivars at three ripening stages. Immature cherries had higher % total phenolics in the IN fraction than mature or overmature cherries. However, immature cherries had the lowest concentrations of these compounds, making the actual bioavailable amounts of these compounds lower than for mature and overmature fruit. High-performance liquid chromatography analysis of Lapins cherries at three maturity stages confirmed the results obtained using spectrophotometric methods for total phenolics and anthocyanins.

  12. Rational design and synthesis of an orally bioavailable peptide guided by NMR amide temperature coefficients

    Science.gov (United States)

    Wang, Conan K.; Northfield, Susan E.; Colless, Barbara; Chaousis, Stephanie; Hamernig, Ingrid; Lohman, Rink-Jan; Nielsen, Daniel S.; Schroeder, Christina I.; Liras, Spiros; Price, David A.; Fairlie, David P.; Craik, David J.

    2014-01-01

    Enhancing the oral bioavailability of peptide drug leads is a major challenge in drug design. As such, methods to address this challenge are highly sought after by the pharmaceutical industry. Here, we propose a strategy to identify appropriate amides for N-methylation using temperature coefficients measured by NMR to identify exposed amides in cyclic peptides. N-methylation effectively caps these amides, modifying the overall solvation properties of the peptides and making them more membrane permeable. The approach for identifying sites for N-methylation is a rapid alternative to the elucidation of 3D structures of peptide drug leads, which has been a commonly used structure-guided approach in the past. Five leucine-rich peptide scaffolds are reported with selectively designed N-methylated derivatives. In vitro membrane permeability was assessed by parallel artificial membrane permeability assay and Caco-2 assay. The most promising N-methylated peptide was then tested in vivo. Here we report a novel peptide (15), which displayed an oral bioavailability of 33% in a rat model, thus validating the design approach. We show that this approach can also be used to explain the notable increase in oral bioavailability of a somatostatin analog. PMID:25416591

  13. Bioavailability of residual polycyclic aromatic hydrocarbons following enhanced natural attenuation of creosote-contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Juhasz, Albert L., E-mail: albert.juhasz@unisa.edu.a [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes Campus, SA 5095 (Australia); Smith, Euan [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes Campus, SA 5095 (Australia); Waller, Natasha [CSIRO Land and Water, Glen Osmond, SA 5064 (Australia); Stewart, Richard [Remediate, Kent Town, SA 5067 (Australia); Weber, John [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes Campus, SA 5095 (Australia)

    2010-02-15

    The impact of residual PAHs (2250 +- 71 mug total PAHs g{sup -1}) following enhanced natural attenuation (ENA) of creosote-contaminated soil (7767 +- 1286 mug total PAHs g{sup -1}) was assessed using a variety of ecological assays. Microtox{sup TM} results for aqueous soil extracts indicated that there was no significant difference in EC{sub 50} values for uncontaminated, pre- and post-remediated soil. However, in studies conducted with Eisenia fetida, PAH bioaccumulation was reduced by up to 6.5-fold as a result of ENA. Similarly, Beta vulgaris L. biomass yields were increased 2.1-fold following ENA of creosote-contaminated soil. While earthworm and plant assays indicated that PAH bioavailability was reduced following ENA, the residual PAH fraction still exerted toxicological impacts on both receptors. Results from this study highlight that residual PAHs following ENA (presumably non-bioavailable to bioremediation) may still be bioavailable to important receptor organisms such as earthworms and plants. - Residual PAHs in creosote-contaminated soil following enhanced natural attenuation impacted negatively on ecological receptors.

  14. Migration and bioavailability of {sup 137}Cs in forest soil of southern Germany

    Energy Technology Data Exchange (ETDEWEB)

    Konopleva, I.; Klemt, E. [Hochschule Ravensburg-Weingarten, University of Applied Sciences, 88250 Weingarten (Germany); Konoplev, A. [Scientific Production Association ' TYPHOON' , Obninsk (Russian Federation); Zibold, G. [Hochschule Ravensburg-Weingarten, University of Applied Sciences, 88250 Weingarten (Germany)], E-mail: zibold@hs-weingarten.de

    2009-04-15

    To give a quantitative description of the radiocaesium soil-plant transfer for fern (Dryopteris carthusiana) and blackberry (Rubus fruticosus), physical and chemical properties of soils in spruce and mixed forest stands were investigated. Of special interest was the selective sorption of radiocaesium, which was determined by measuring the Radiocaesium Interception Potential (RIP). Forest soil and plants were taken at 10 locations of the Altdorfer Wald (5 sites in spruce forest and 5 sites in mixed forest). It was found that the bioavailability of radiocaesium in spruce forest was on average seven times higher than in mixed forest. It was shown that important factors determining the bioavailability of radiocaesium in forest soil were its exchangeability and the radiocaesium interception potential (RIP) of the soil. Low potassium concentration in soil solution of forest soils favors radiocaesium soil-plant transfer. Ammonium in forest soils plays an even more important role than potassium as a mobilizer of radiocaesium. The availability factor - a function of RIP, exchangeability and cationic composition of soil solution - characterized reliably the soil-plant transfer in both spruce and mixed forest. For highly organic soils in coniferous forest, radiocaesium sorption at regular exchange sites should be taken into account when its bioavailability is considered.

  15. Improving the oral bioavailability of curcumin using novel organogel-based nanoemulsions.

    Science.gov (United States)

    Yu, Hailong; Huang, Qingrong

    2012-05-30

    Curcumin is a natural bioactive compound with many health-promoting benefits. Its low oral bioavailability limits its application in functional foods. In the present study, novel organogel-based nanoemulsions have been developed for oral delivery of curcumin and improvement of its bioavailability. Recently developed curcumin organogel was used as the oil phase in the curcumin nanoemulsion formulation. Tween 20 was selected as the emulsifier on the basis of maximum in vitro bioaccessibility of curcumin in the nanoemulsion. In vitro lipolysis profile revealed that the digestion of nanoemulsion was significantly faster and more complete than the organogel. Permeation experiments on Caco-2 cell monolayers suggested that digestion-diffusion was the major absorption mechanism for curcumin in the nanoemulsion. Furthermore, in vivo pharmacokinetics analysis on mice confirmed that the oral bioavailability of curcumin in the nanoemulsion was increased by 9-fold compared with unformulated curcumin. This novel formulation approach may also be used for oral delivery of other poorly soluble nutraceuticals with high loading capacity, which has significant impact in functional foods, dietary supplements and pharmaceutical industries.

  16. Studies on inclusion complex as potential systems for enhancement of oral bioavailability of olmesartan medoxomil

    Directory of Open Access Journals (Sweden)

    Hetal Paresh Thakkar

    2012-01-01

    Full Text Available Background: Olmesartan medoxomil (OLM, an anti-hypertensive agent administered orally, has absolute bioavailability of only 26% due to the poor aqueous solubility (7.75 μg/ml. Inclusion complexation with cyclodextrins (CD has been reported to increase the aqueous solubility of various compounds. Aim: The present investigation aimed to enhancing the oral bioavailability of OLM by inclusion complexation with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD. Materials and Methods: The inclusion complexes with HP-β-CD were prepared using two different methods, viz., physical mixture and kneading. The prepared complexes were characterized for various parameters such as drug content, aqueous solubility, dissolution study, in vitro diffusion, intestinal permeability and stability study. The formation of the inclusion complex was confirmed by differential scanning calorimetry, X-ray diffraction, and Fourier transform infrared spectroscopy. Results: The solubility, dissolution, diffusion rate, and intestinal permeability of the prepared complexes were found to be significantly higher than that of the plain drug. Among the two methods used for formation of inclusion complex, KN method gave higher solubility rates and hence is a better method when compared with PM. Conclusion: The approach seems to be promising in improving the oral bioavailability of OLM.

  17. Phenolic Esters of O-Desmethylvenlafaxine with Improved Oral Bioavailability and Brain Uptake

    Directory of Open Access Journals (Sweden)

    Yang Zhang

    2013-12-01

    Full Text Available O-Desmethylvenlafaxine (desvenlafaxine, ODV is a recently approved antidepressant which in some clinical studies failed to meet a satisfactory end-point. The aim of this study was to prepare a series of phenolic esters of ODV and evaluate their potential as ODV prodrugs with improved brain uptake. Fifteen phenolic esters (compounds 1a–o were synthesized and their pharmacokinetic profiles evaluated in rat. The four compounds producing the highest relative bioavailability of ODV in rat (compounds 1c, 1e, 1n, 1o were then studied to evaluate their brain uptake. Of these four compounds, compound 1n (the piperonylic acid ester of ODV demonstrated the highest Cmax of ODV both in the rat hypothalamus and total brain. Finally the pharmacokinetics of 1n were evaluated in beagle dog where the increase in relative bioavailability of ODV was found to be as great as in rat. This high relative bioavailability of ODV coupled with its good brain penetration make 1n the most promising candidate for development as an ODV prodrug.

  18. Lycopene Content of Tomato Products: Its Stability, Bioavailability and In Vivo Antioxidant Properties.

    Science.gov (United States)

    Agarwal, Anita; Shen, Honglei; Agarwal, Sanjiv; Rao, A. V.

    2001-01-01

    Lycopene is a bioactive carotenoid present in many fruits and vegetables. Tomatoes constitute the major dietary source of lycopene. Recent evidence shows lycopene to be associated with several health benefits. However, very little information is available about the stability of lycopene and its bioavailability. Because tomatoes undergo extensive processing and storage before consumption, a study was conducted to evaluate the stability, isomeric form, bioavailability, and in vivo antioxidant properties of lycopene. Total lycopene and isomers were measured by spectrophotometry and high-performance liquid chromatography, respectively. Lycopene content of tomatoes remained unchanged during the multistep processing operations for the production of juice or paste and remained stable for up to 12 months of storage at ambient temperature. Moreover, subjecting tomato juice to cooking temperatures in the presence of corn oil resulted in the formation of the cis isomeric form, which was considered to be more bioavailable. Lycopene was absorbed readily from the dietary sources. Serum lipid and low-density lipoprotein oxidation were significantly reduced after the consumption of tomato products containing lycopene.

  19. Cefdinir Solid Dispersion Composed of Hydrophilic Polymers with Enhanced Solubility, Dissolution, and Bioavailability in Rats

    Directory of Open Access Journals (Sweden)

    Hyun-Jong Cho

    2017-02-01

    Full Text Available The aim of this work was to develop cefdinir solid dispersions (CSDs prepared using hydrophilic polymers with enhanced dissolution/solubility and in vivo oral bioavailability. CSDs were prepared with hydrophilic polymers such as hydroxypropyl-methylcellulose (HPMC; CSD1, carboxymethylcellulose-Na (CMC-Na; CSD2, polyvinyl pyrrolidone K30 (PVP K30; CSD3 at the weight ratio of 1:1 (drug:polymer using a spray-drying method. The prepared CSDs were characterized by aqueous solubility, differential scanning calorimetry (DSC, powder X-ray diffraction (p-XRD, scanning electron microscopy (SEM, aqueous viscosity, and dissolution test in various media. The oral bioavailability of CSDs was also evaluated in rats and compared with cefdinir powder suspension. The cefdinir in CSDs was amorphous form, as confirmed in the DSC and p-XRD measurements. The developed CSDs commonly resulted in about 9.0-fold higher solubility of cefdinir and a significantly improved dissolution profile in water and at pH 1.2, compared with cefdinir crystalline powder. Importantly, the in vivo oral absorption (represented as AUCinf was markedly increased by 4.30-, 6.77- and 3.01-fold for CSD1, CSD2, and CSD3, respectively, compared with cefdinir suspension in rats. The CSD2 prepared with CMC-Na would provide a promising vehicle to enhance dissolution and bioavailability of cefdinir in vivo.

  20. Application of hot melt extrusion to enhance the dissolution and oral bioavailability of oleanolic acid

    Directory of Open Access Journals (Sweden)

    Nannan Gao

    2017-01-01

    Full Text Available The aim of this study was to improve the in vitro dissolution rate and oral bioavailability of oleanolic acid (OA, a water insoluble drug belonging to BCS class IV. Hot melt extrusion (HME was applied to develop OA amorphous solid dispersions. The characterizations of the optimal formulation were performed by differential scanning calorimetry, X-ray powder diffraction, Fourier transform infrared spectroscopy and in vitro dissolution test. The in vivo pharmacokinetic study was conducted in rats. As a result, OA solid dispersion based on PVP VA 64 (OA-PVP was successfully prepared. In the dissolution medium containing 0.3% SDS, OA-PVP dramatically increased the releasing rate of OA compared with the physical mixture (PM-PVP and commercial tablet. Furthermore, OA-PVP exhibited higher AUC (P < 0.05 and Cmax (P < 0.05 than PM-PVP and commercial tablet. The superior dissolution property and bioavailability of OA-PVP mainly attributed to the amorphous state of OA in PVP VA64 and the well dispersion caused by thermal melting and shearing. Overall, hot melt extrusion was an efficient strategy to enhance the dissolution rate and oral bioavailability of OA.

  1. Improving dissolution and oral bioavailability of pranlukast hemihydrate by particle surface modification with surfactants and homogenization

    Directory of Open Access Journals (Sweden)

    Ha ES

    2015-06-01

    Full Text Available Eun-Sol Ha,1 In-hwan Baek,2 Jin-Wook Yoo,1 Yunjin Jung,1 Min-Soo Kim1 1College of Pharmacy, Pusan National University, 2College of Pharmacy, Kyungsung University, Busan, Republic of Korea Abstract: The present study was carried out to develop an oral formulation of pranlukast hemihydrate with improved dissolution and oral bioavailability using a surface-modified microparticle. Based on solubility measurements, surface-modified pranlukast hemihydrate microparticles were manufactured using the spray-drying method with hydroxypropylmethyl cellulose, sucrose laurate, and water and without the use of an organic solvent. The hydrophilicity of the surface-modified pranlukast hemihydrate microparticle increased, leading to enhanced dissolution and oral bioavailability of pranlukast hemihydrate without a change in crystallinity. The surface-modified microparticles with an hydroxypropylmethyl cellulose/sucrose laurate ratio of 1:2 showed rapid dissolution of up to 85% within 30 minutes in dissolution medium (pH 6.8 and oral bioavailability higher than that of the commercial product, with approximately 2.5-fold and 3.9-fold increases in area under the curve (AUC0→12 h and peak plasma concentration, respectively. Therefore, the surface-modified microparticle is an effective oral drug delivery system for the poorly water-soluble therapeutic pranlukast hemihydrate. Keywords: solubility, wettability, sucrose laurate, cellulose

  2. Aging effect on the mobility and bioavailability of copper in soil

    Institute of Scientific and Technical Information of China (English)

    LU Anxiang; ZHANG Shuzhen; QIN Xiangyang; WU Wenyong; LIU Honglu

    2009-01-01

    Aging effect on the mobility and bioavailability of copper (Cu) was investigated using a spiked soil with different incubation periods from 3 to 56 d. Wheat was planted and earthworm was cultured separately in the incubated soils. The mobility of Cu in soil was evaluated by a chemical fractionation scheme and the toxicity and bioavailability were assessed by measuring the biomass and Cu concentration in tissues. Results showed that aging had a significant effect on Cu fraction distribution, of which Cu tended to incorporate from the exchangeable into more stable fractions such as the reducible and oxidisable fractions. However, aging had little effect on Cu bioavailability to wheat and earthworms. Comparing the soil being incubated for 3 d and 56 d, Cu concentration in wheat roots decreased from 14.5 to 12.8 mg/kg, and no significant changes in Cu concentration were observed in both wheat shoots and earthworms. The Cu concentration was around 2.0 and 50 mg/kg for wheat shoots and earthworms, respectively, irrespective of soil incubation time. The CaCl2-extractable Cu had a linear relationship with Cu concentration in wheat roots (R2 = 0.65, P < 0.05), but no linear relationship can be found for wheat shoots and earthworms. Biological control may be more crucial for Cu accumulation in organism than the changes in soil Cu fraction caused by aging.

  3. Bioavailability and pharmacokinetics of sorafenib suspension, nanoparticles and nanomatrix for oral administration to rat.

    Science.gov (United States)

    Wang, Xue-qing; Fan, Jie-ming; Liu, Ya-ou; Zhao, Bo; Jia, Zeng-rong; Zhang, Qiang

    2011-10-31

    Sorafenib is slightly absorbed in the gastrointestinal tract due to its poor solubility in water. To improve its absorption, a novel nanoparticulate formulation-nanomatrix was used in the study. The nanomatrix was a system prepared from a porous material Sylysia(®) 350 and a pH sensitive polymer Eudragit(®). The formulations were optimized by orthogonal design (L(9)(3(4))) and their bioavailability were evaluated in rat, comparing to pH-sensitive Eudragit nanoparticles and suspension of sorafenib. In the formulations, the ratio of sorafenib to Eudragit(®) S100 was found to be more important determinant of the sorafenib bioavailability than the ratio of sorafenib to Sylysia(®) 350. As for the bioavailability, the AUC(0-36 h) of sorafenib nanomatrix was 13-33 times to that of sorafenib suspension, but only 16.8% to 40.8% that of Eudragit(®) S100 nanoparticles. This may be resulted from the different drug dispersion degree, release character and bioadhension activity. However, because all the materials used in the nanomatrix formulation are commonly adjuvant, safe, easy to get and cheap, above all, the nanomatrix formulation can solve the stability and scaling up problems in the nanoparticles, it had potential to develop into a product in the future.

  4. Formulation and evaluation of acyclovir nanosuspension for enhancement of oral bioavailability

    Directory of Open Access Journals (Sweden)

    Mangesh Ramesh Bhalekar

    2014-01-01

    Full Text Available Acyclovir, an antiviral drug used against herpes simplex virus and varicella zoster virus. The dose ranges between 200 and 800 mg and the oral bioavailability is 10-20%, which decreases as the dose is increased. The aim of this research work was to formulate and characterize nanosuspensions of acyclovir with an intention to increase the oral bioavailability. Nanosuspensions were prepared by the precipitation-ultra sonication method and the effects of important process parameters i.e., precipitation temperature, stirring speed, end point temperature of probe sonicator, energy input and sonication time were investigated systematically, the optimal nanosuspension (particle size 274 nm was obtained at values of 4°C, 10,000 rpm, 30°C, 600 Watt and 20 min, respectively. The nanosuspension was lyophilized using different matrix formers and sucrose (100% w/w to drug was found to prevent agglomeration and particle size upon reconstitution was found to be 353 nm. The lyophilized nanocrystals appeared flaky in scanning electron microscopy images, the X-ray powder diffraction and differential scanning calorimetry analysis showed the nanoparticles to be in the crystalline state. Ex vivo permeation study for calculating absorption rate and in vivo bioavailability area under the curve both showed three-fold increase over marketed suspension.

  5. Enhanced bioavailability of danazol nanosuspensions by wet milling and high-pressure homogenization

    Science.gov (United States)

    Kanthamneni, Naveen; Valiveti, Satyanarayana; Patel, Mita; Xia, Heather; Tseng, Yin-Chao

    2016-01-01

    Introduction: The majority of drugs obtained through synthesis and development show poor aqueous solubility and dissolution velocity, resulting in reduced bioavailability of drugs. Most of these problems arise from formulation-related performance issues, and an efficient way to overcome these obstacles and to increase dissolution velocity is to reduce the particle size of drug substances to form drug nanosuspensions. Materials and Methods: Danazol nanosuspensions were prepared by wet milling (WM) and high-pressure homogenization (HPH) methods. The nanosuspensions obtained using these fabrication methods were analyzed for their particle size, surface charge, and the crystallinity of the product was assessed by X-ray diffraction (XRD) and differential scanning calorimetry techniques. To determine in vitro and in vivo performances of the prepared nanosuspensions, dissolution velocity, and bioavailability studies were performed. Results: Particle size and zeta potential analysis showed the formation of nanosized particles with a negative charge on the surface. XRD depicted the nanocrystalline nature of danazol with low diffraction intensities. With increased surface area and saturation solubility, the nanosuspensions showed enhanced dissolution velocity and oral bioavailability in rats when compared to the bulk danazol suspension. Conclusions: The results suggest that the preparation of nanosuspensions by WM or HPH is a promising approach to formulate new drugs or to reformulate existing drugs with poorly water-soluble properties. PMID:28123991

  6. Development of Liposome containing sodium deoxycholate to enhance oral bioavailability of itraconazole

    Directory of Open Access Journals (Sweden)

    Zhenbao Li

    2017-03-01

    Full Text Available The aim of this study was to enhance oral bioavailability of itraconazole (ITZ by developing Liposome containing sodium deoxycholate (ITZ-Lip-NaDC. The liposome, consisting of egg yolk lecithin and sodium deoxycholate, was prepared by thin-film dispersion method. Differential Scanning Calorimetry (DSC results indicated an amorphous state in the liposome. The physicochemical characteristics including particle size, morphology, entrapment efficiency, dissolution properties were also investigated. The performance of single-pass intestinal infusion exhibited that the transport order of intestinal segment was jejunum, duodenum, colon and ileum, and that all the segments participated in the absorption of ITZ in intestinal tract. The bioavailability study in rats showed that the AUC0-72 of the liposome was nearly 1.67-fold higher than that of commercial capsules (SPORANOX in terms of oral administration, and the RSD of AUC0-72 of ITZ-Lip-NaDC was also decreased. Our results indicated that ITZ-Lip-NaDC liposome was facilitated to improve dissolution efficiency, augment transmembrane absorption, and then enhance the oral bioavailability of ITZ, successfully.

  7. Bioavailability of zinc in Wistar rats fed with rice fortified with zinc oxide.

    Science.gov (United States)

    Della Lucia, Ceres Mattos; Santos, Laura Luiza Menezes; Rodrigues, Kellen Cristina da Cruz; Rodrigues, Vivian Cristina da Cruz; Martino, Hércia Stampini Duarte; Sant'Ana, Helena Maria Pinheiro

    2014-06-13

    The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice®) is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn) in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3)), supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca) and magnesium (Mg) in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p 0.05) for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification.

  8. Development and Evaluation of Solid Lipid Nanoparticles of Raloxifene Hydrochloride for Enhanced Bioavailability

    Directory of Open Access Journals (Sweden)

    Anand Kumar Kushwaha

    2013-01-01

    Full Text Available Raloxifene hydrochloride (RL-HCL is an orally selective estrogen receptor modulator (SERM with poor bioavailability of nearly 2% due to its poor aqueous solubility and extensive first pass metabolism. In order to improve the oral bioavailability of raloxifene, raloxifene loaded solid lipid nanoparticles (SLN have been developed using Compritol 888 ATO as lipid carrier and Pluronic F68 as surfactant. Raloxifene loaded SLN were prepared by solvent emulsification/evaporation method, and different concentrations of surfactant, and homogenization speed were taken as process variables for optimization. SLN were characterized for particle size, zeta potential, entrapment efficiency, surface morphology, and crystallinity of lipid and drug. In vitro drug release studies were performed in phosphate buffer of pH 6.8 using dialysis bag diffusion technique. Particle sizes of all the formulations were in the range of 250 to 1406 nm, and the entrapment efficiency ranges from 55 to 66%. FTIR and DSC studies indicated no interaction between drug and lipid, and the XRD spectrum showed that RL-HCL is in amorphous form in the formulation. In vitro release profiles were biphasic in nature and followed Higuchi model of release kinetics. Pharmacokinetics of raloxifene loaded solid lipid nanoparticles after oral administration to Wistar rats was studied. Bioavailability of RL-HCL loaded SLN was nearly five times than that of pure RL-HCL.

  9. Increasing the oral bioavailability of the poorly water soluble drug itraconazole with ordered mesoporous silica.

    Science.gov (United States)

    Mellaerts, Randy; Mols, Raf; Jammaer, Jasper A G; Aerts, Caroline A; Annaert, Pieter; Van Humbeeck, Jan; Van den Mooter, Guy; Augustijns, Patrick; Martens, Johan A

    2008-05-01

    This study aims to evaluate the in vivo performance of ordered mesoporous silica (OMS) as a carrier for poorly water soluble drugs. Itraconazole was selected as model compound. Physicochemical characterization was carried out by SEM, TEM, nitrogen adsorption, DSC, TGA and in vitro dissolution. After loading itraconazole into OMS, its oral bioavailability was compared with the crystalline drug and the marketed product Sporanox in rabbits and dogs. Plasma concentrations of itraconazole and OH-itraconazole were determined by HPLC-UV. After administration of crystalline itraconazole in dogs (20mg), no systemic itraconazole could be detected. Using OMS as a carrier, the AUC0-8 was boosted to 681+/-566 nM h. In rabbits, the AUC0-24 increased significantly from 521+/-159 nM h after oral administration of crystalline itraconazole (8 mg) to 1069+/-278 nM h when this dose was loaded into OMS. Tmax decreased from 9.8+/-1.8 to 4.2+/-1.8h. No significant differences (AUC, Cmax, and Tmax) could be determined when comparing OMS with Sporanox in both species. The oral bioavailability of itraconazole formulated with OMS as a carrier compares well with the marketed product Sporanox, in rabbits as well as in dogs. OMS can therefore be considered as a promising carrier to achieve enhanced oral bioavailability for drugs with extremely low water solubility.

  10. Mobility and bioavailability reduction of soil TNT via sorption enhancement using monopotassium phosphate.

    Science.gov (United States)

    Jung, Jae-Woong; Nam, Kyoungphile

    2014-06-30

    In this study, the effect of monopotassium phosphate (MKP) on the reduction in mobility and bioavailability of 2,4,6-trinitrotoluene (TNT) was tested. In the test soil, collected from an active firing range, of which cation binding sites were mostly exchanged with H(+) or Al(3+), potassium ions in MKP exchanged the existing cations and hence significantly increased TNT sorption. In addition, a competitive sorption experiment with hexafluorobenzene and 2,4-dinitrotoluene suggests that TNT was specifically sorbed through cation-polar interaction in the test soil. The unit-equivalent Freundlich sorption coefficient of TNT in MKP-amended soil (1370.96 mg-TNT/kg-soil) was about 13 times higher than that in untreated soil (106.23 mg-TNT/kg-soil). Finally, modified synthetic precipitation leaching procedure and hydroxypropyl-β-cyclodextrin extraction result revealed that MKP application could reduce both the leachability and bioavailability of soil TNT. The leachable and extractable fraction of TNT in untreated soil were 87.63% and 94.47% of the initial TNT, respectively, whereas these fractions decreased to 49.15% and 54.85% of the initial TNT in the presence of MKP, respectively. MKP application can be a benign technology which can reduce both mobility and bioavailability of TNT in soil.

  11. Effect of Helicobacter pylori infection and acid blockade by lansoprazole on clarithromycin bioavailability

    Directory of Open Access Journals (Sweden)

    R.A.M. Ortiz

    2007-03-01

    Full Text Available The effect of proton pump inhibitors and Helicobacter pylori infection on the bioavailability of antibiotics is poorly understood. We determined the effects of 5-day oral administration of 60 mg lansoprazole on the bioavailability of clarithromycin in individuals with and without H. pylori infection. Thirteen H. pylori-infected and 10 non-infected healthy volunteers were enrolled in a study with an open-randomized two-period crossover design and a 21-day washout period between phases. Plasma concentrations of clarithromycin in subjects with and without lansoprazole pre-treatment were measured by liquid chromatography coupled to a tandem mass spectrometer. Clarithromycin Cmax and AUC0-10 h were significantly reduced after lansoprazole administration. In addition, lansoprazole treatment of the H. pylori-positive group resulted in a statistically significant greater reduction in Cmax (40 vs 15% and AUC0-10 h (30 vs 10% compared to lansoprazole-treated H. pylori-negative subjects. Thus, treatment with lansoprazole for 5 days reduced bioavailability of clarithromycin, irrespective of H. pylori status. This reduction, however, was even more pronounced in H. pylori-infected individuals.

  12. Variations in the bioavailability of polycyclic aromatic hydrocarbons in industrial and agricultural soils after bioremediation.

    Science.gov (United States)

    Guo, Meixia; Gong, Zongqiang; Allinson, Graeme; Tai, Peidong; Miao, Renhui; Li, Xiaojun; Jia, Chunyun; Zhuang, Jie

    2016-02-01

    The aim of this study was to demonstrate the variations in bioavailability remaining in industrial and agricultural soils contaminated by polycyclic aromatic hydrocarbons (PAHs) after bioremediation. After inoculation of Mycobacterium sp. and Mucor sp., PAH biodegradation was tested on a manufactured gas plant (MGP) soil and an agricultural soil. PAH bioavailability was assessed before and after biodegradation using solid-phase extraction (Tenax-TA extraction) and solid-phase micro-extraction (SPME) to represent bioaccessibility and chemical activity of PAHs, respectively. Only 3- and 4-ring PAHs were noticeably biodegradable in the MGP soil. PAH biodegradation in the agricultural soil was different from that in the MGP soil. The rapidly desorbing fractions (F(rap)) extracted by Tenax-TA and the freely dissolved concentrations of 3- and 4-ring PAHs determined by SPME from the MGP soil decreased after 30 days biodegradation; those values of the 5- and 6-ring PAHs changed to a lesser degree. For the agricultural soil, the F(rap) values of the 3- and 4-ring PAHs also decreased after the biodegradation experiment. The Tenax-TA extraction and the SPME have the potential to assess variations in the bioavailability of PAHs and the degree of biodegradation in contaminated MGP soils. In addition, Tenax-TA extraction is more sensitive than SPME when used in the agricultural soil.

  13. Speciation and bioavailability of soil nutrients: effect on crop production and environment

    Directory of Open Access Journals (Sweden)

    Elisabetta Barberis

    Full Text Available The agricultural production, determining the quality of the foodstuffs, depends on the biological characteristics of the crops and on the environmental properties, where soil environment plays a central role. Crops absorb water and nutritive elements from soil, but they can intake toxic elements as well. The potential benefits, or dangers, due to the presence of a certain element in soil, depend on its chemical speciation regulating its bioavailability, toxicity, environmental mobility, and biogeochemistry. Elements may exist in soil in different redox species and organic or inorganic forms. They may thus undergo different chemical processes occurring in solution, in the solid phase, or at the solid-water interface. The chemical speciation and bioavailability of the elements are affected by soil and environmental properties, which may undergo natural or anthropogenic modifications. As an example, we reported here some aspects linked to the chemical speciation, bioavailability and environmental fate of two chemically similar elements. The former, phosphorus, is a macronutrient element, essential for plant growth, while the latter, arsenic, is strongly toxic for most living organisms.

  14. On the bioavailability of flavanols and anthocyanins: flavanol-anthocyanin dimers.

    Science.gov (United States)

    Fernandes, Iva; Nave, Frederico; Gonçalves, Rui; de Freitas, Victor; Mateus, Nuno

    2012-11-15

    The bioavailability of flavanols, anthocyanins and anthocyanin-derived pigments like flavanol-anthocyanin dimers already reported to occur in food products is a major unsolved issue. The absorption of the flavanol-anthocyanin dimer (+)-catechin-(4,8)-malvidin-3-O-glucoside (Cat-Mv3glc) through Caco-2 cells was assessed by performing transepithelial transport assays. The ability of Cat-Mv3glc to cross Caco-2 cells was compared with that of malvidin-3-glucoside (Mv3glc), (+)-catechin (Cat) and procyanidin B3 (Cat-Cat), in order to evaluate the influence of some structural features on the transport efficiency. The flavanol-anthocyanin dimer was absorbed in this intestinal model although with a lower efficiency than the monomers Cat and Mv3glc. On the other hand, Cat-Mv3glc was found to cross the intestinal barrier model more significantly than Cat-Cat. This feature may be related to the presence of the glucose moiety in its structure. Overall, this study brings more insights into the bioavailability of anthocyanins and flavanols and represents the first report on the bioavailability of flavanol-anthocyanins.

  15. Improving dissolution and oral bioavailability of pranlukast hemihydrate by particle surface modification with surfactants and homogenization

    Science.gov (United States)

    Ha, Eun-Sol; Baek, In-hwan; Yoo, Jin-Wook; Jung, Yunjin; Kim, Min-Soo

    2015-01-01

    The present study was carried out to develop an oral formulation of pranlukast hemihydrate with improved dissolution and oral bioavailability using a surface-modified microparticle. Based on solubility measurements, surface-modified pranlukast hemihydrate microparticles were manufactured using the spray-drying method with hydroxypropylmethyl cellulose, sucrose laurate, and water and without the use of an organic solvent. The hydrophilicity of the surface-modified pranlukast hemihydrate microparticle increased, leading to enhanced dissolution and oral bioavailability of pranlukast hemihydrate without a change in crystallinity. The surface-modified microparticles with an hydroxypropylmethyl cellulose/sucrose laurate ratio of 1:2 showed rapid dissolution of up to 85% within 30 minutes in dissolution medium (pH 6.8) and oral bioavailability higher than that of the commercial product, with approximately 2.5-fold and 3.9-fold increases in area under the curve (AUC0→12 h) and peak plasma concentration, respectively. Therefore, the surface-modified microparticle is an effective oral drug delivery system for the poorly water-soluble therapeutic pranlukast hemihydrate. PMID:26150699

  16. Cosmic meteor dust: potentially the dominant source of bio-available iron in the Southern Ocean

    Science.gov (United States)

    Dyrud, L. P.; Marsh, D. R.; Del Castillo, C. E.; Fentzke, J.; Lopez-Rosado, R.; Behrenfeld, M.

    2012-12-01

    Johnson, 2001 [Johnson, Kenneth. S. (2001), Iron supply and demand in the upper ocean: Is extraterrestrial dust a significant source of bioavailable iron?, Global Biogeochem. Cycles, 15(1), 61-63, doi:10.1029/2000GB001295], first suggested that meteoric particulate flux could be a significant source of bio-available iron, particularly in regions with little or no eolean sources, such as the Southern Ocean. While these calculations raised intriguing questions, there were many large unknowns in the input calculations between meteor flux and bio-available ocean molecular densities. There has been significant research in the intervening decade on related topics, such as the magnitude (~200 ktons per year) and composition of the meteoric flux, its atmospheric evaporation, transport, mesospheric formation of potentially soluble meteoric smoke, and extraterrestrial iron isotope identification. Paramount of these findings are recent NCAR WACCM atmosphere model results demonstrating that the majority of meteoric constituents are transported towards the winter poles and the polar vortex. This may lead to a focusing of meteoritic iron deposition towards the Southern Ocean. We present a proposed research plan involving Southern Ocean sample collection and analysis and atmospheric and biological modeling to determine both the current relevance of meteoric iron, and examine the past and future consequences of cosmic dust under a changing climate.

  17. 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.

  18. The preparation and evaluation of water-soluble SKLB610 nanosuspensions with improved bioavailability.

    Science.gov (United States)

    Huang, Yunchuang; Luo, Xun; You, Xinyu; Xia, Yong; Song, Xuejiao; Yu, Luoting

    2013-09-01

    The aim of the study was to investigate the potential of nanosuspension to enhance the bioavailability of SKLB610 (Biopharmaceutical Classification System class II drug), a bioactive anticancer compound synthesized in our labs. SKLB610 nanosuspensions were prepared using wet media milling. Physicochemical characteristics of the nanosuspensions were evaluated, including particle size and distribution, dissolution, transmission electron microscopy, atomic force microscopy, thermogravimetric analysis, and X-ray powder diffractometry. The dissolution rate of SKLB610 was greatly improved in nanosuspensions, compared to crude SKLB610. Pharmacokinetic studies in rats demonstrated that the oral bioavailability of SKLB610 in nanosuspension (89.4%) was 2.6-fold higher than in coarse suspension (34.1%). Stabilizer type, milling time, and milling speed had a significant effect on particle size of the SKLB610 nanosuspensions. Nanosuspensions effectively improved the dissolution rate and bioavailability of the water-insoluble drug SKLB610 by reducing the compound particle size to the nanoscale and employing a proper formulation.

  19. Diurnal rhythmicity in biological processes involved in bioavailability of functional food factors.

    Science.gov (United States)

    Tsurusaki, Takashi; Sakakibara, Hiroyuki; Aoshima, Yoshiki; Yamazaki, Shunsuke; Sakono, Masanobu; Shimoi, Kayoko

    2013-05-01

    In the past few decades, many types of functional factors have been identified in dietary foods; for example, flavonoids are major groups widely distributed in the plant kingdom. However, the absorption rates of the functional food factors are usually low, and many of these are difficult to be absorbed in the intact forms because of metabolization by biological processes during absorption. To gain adequate beneficial effects, it is therefore mandatory to know whether functional food factors are absorbed in sufficient quantity, and then reach target organs while maintaining beneficial effects. These are the reasons why the bioavailability of functional food factors has been well investigated using rodent models. Recently, many of the biological processes have been reported to follow diurnal rhythms recurring every 24 h. Therefore, absorption and metabolism of functional food factors influenced by the biological processes may vary with time of day. Consequently, the evaluation of the bioavailability of functional food factors using rodent models should take into consideration the timing of consumption. In this review, we provide a perspective overview of the diurnal rhythm of biological processes involved in the bioavailability of functional food factors, particularly flavonoids.

  20. Bioavailability of Silica, Titanium Dioxide, and Zinc Oxide Nanoparticles in Rats.

    Science.gov (United States)

    Kim, Mi-Kyung; Lee, Jeong-A; Jo, Mi-Rae; Choi, Soo-Jin

    2016-06-01

    Inorganic nanoparticles have been widely applied to various industrial fields and biological applications. However, the question as to whether nanoparticles are more efficiently absorbed into the systemic circulation than bulk-sized materials remains to be unclear. In the present study, the physico-chemical and dissolution properties of the most extensively developed inorganic nanoparticles, such as silica (SiO2), titanium dioxide (TiO2), and zinc oxide (ZnO), were analyzed, as compared with bulk-sized particles. Furthermore, the bioavailability of nanoparticles versus their bulk counterparts was evaluated in rats after a single oral administration and intravenous injection, respectively. The results demonstrated that all bulk materials had slightly higher crystallinity than nanoparticles, however, their dissolution properties were not affected by particle size. No significant difference in oral absorption and bioavailability of both SiO2 and TiO2 was found between nano- and bulk-sized materials, while bulk ZnO particles were more bioavailable in the body than ZnO nanoparticles. These finding will provide critical information to apply nanoparticles with high efficiency as well as to predict their toxicity potential.

  1. Part II: bioavailability in beagle dogs of nimodipine solid dispersions prepared by hot-melt extrusion.

    Science.gov (United States)

    Zheng, Xin; Yang, Rui; Zhang, Yu; Wang, Zhijun; Tang, Xing; Zheng, Liangyuan

    2007-07-01

    The aim of the present work was to investigate the in vitro dissolution properties and oral bioavailability of three solid dispersions of nimodipine. The solid dispersions were compared with pure nimodipine, their physical mixtures, and the marketed drug product Nimotop. Nimodipine solid dispersions were prepared by a hot-melt extrusion process with hydroxypropyl methylcellulose (HPMC, Methocel E5), polyvinylpyrrolidone/vinyl acetate copolymer (PVP/VA, Plasdone S630), and ethyl acrylate, methyl methacrylate polymer (Eudragit EPO). Previous studies of XRPD and DSC data showed that the crystallinity was not observed in hot-melt extrudates, two T(g)s were observed in the 30% and 50% NMD-HPMC samples, indicating phase separation. The weakening and shift of the N-H stretching vibration of the secondary amine groups of nimodipine as determined by FT-IR proved hydrogen bonding between the drug and polymers in the solid dispersion. The dissolution profiles of the three dispersion systems showed that the release was improved compared with the unmanipulated drug. Drug plasma concentrations were determined by HPLC, and pharmacokinetic parameters were calculated after orally administering each preparation containing 60 mg of nimodipine. The mean bioavailability of nimodipine was comparable after administration of the Eudragit EPO solid dispersion and Nimotop, but the HPMC and PVP/VA dispersions exhibited much lower bioavailability. However, the AUC(0-12 hr) values of all three solid dispersions were significantly higher than physical mixtures with the same carriers and nimodipine powder.

  2. In vitro bioavailability of heavy metals in pressure-treated wood dust.

    Science.gov (United States)

    Gordon, Terry; Spanier, Jonathan; Butala, John H; Li, Ping; Rossman, Toby G

    2002-05-01

    Pressure treatment with chromium, copper, and arsenic (CCA) is the most prevalent method for protecting wood used in outdoor construction projects. Although these metals are tightly bound to the wood fibers and are not released under most conditions of use, we examined the bioavailability of metals in CCA pressure-treated wood dust in vitro. Cytotoxicity and metallothionein (MT) mRNA expression were examined in V79 Chinese hamster lung fibroblast cells incubated with respirable-size wood dust generated by sanding CCA-treated and untreated (control) Southern yellow pine. In colony survival studies, increased cytotoxicity (p wood dust (351 +/- 77 microg/ml, mean +/- SE) compared with control wood dust (883 +/- 91 microg/ml). Increased cytotoxicity with CCA wood dust also occurred in an arsenic resistant subline of V79 cells, thus suggesting that arsenic was not responsible for the increased cytotoxicity. Metallothionein mRNA was significantly increased after 48 h of treatment with CCA wood dust compared with control wood dust. Incubation of CCA wood dust in cell culture media resulted in the transfer of copper, but not chromium or arsenic, into the media. Moreover, the treatment of cells with this filtered extract resulted in significantly increased metallothionein mRNA, suggesting that bioavailable copper is responsible for inducing metallothionein mRNA in V79 cells. Thus, these bioassays suggest that metals become bioavailable during in vitro culture of phagocytic V79 cells with CCA wood dust.

  3. [Silica-coated ethosome as a novel oral delivery system for enhanced oral bioavailability of curcumin].

    Science.gov (United States)

    Li, Chong; Deng, Li; Zhang, Yan; Su, Ting-Ting; Jiang, Yin; Chen, Zhang-Bao

    2012-11-01

    The aim of this study is to investigate the feasibility of silica-coated ethosome as a novel oral delivery system for the poorly water-soluble curcumin (as a model drug). The silica-coated ethosomes loading curcumin (CU-SE) were prepared by alcohol injection method with homogenization, followed by the precipitation of silica by sol-gel process. The physical and chemical features of CU-SEs, and curcumin release were determined in vitro. The pharmacodynamics and bioavailability measurements were sequentially performed. The mean diameter of CU-SE was (478.5 +/- 80.3) nm and the polydispersity index was 0.285 +/- 0.042, while the mean value of apparent drug entrapment efficiency was 80.77%. In vitro assays demonstrated that CU-SEs were significantly stable with improved release properties when compared with curcumin-loaded ethosomes (CU-ETs) without silica-coatings. The bioavailability of CU-SEs and CU-ETs was 11.86- and 5.25-fold higher, respectively, than that of curcumin suspensions (CU-SUs) in in vivo assays. The silica coatings significantly promoted the stability of ethosomes and CU-SEs exhibited 2.26-fold increase in bioavailablity relative to CU-ETs, indicating that the silica-coated ethosomes might be a potential approach for oral delivery of poorly water-soluble drugs especially the active ingredients of traditional Chinese medicine with improved bioavailability.

  4. Development and characterization of nanosuspensions of olmesartan medoxomil for bioavailability enhancement

    Directory of Open Access Journals (Sweden)

    Hetal Paresh Thakkar

    2011-01-01

    Full Text Available Background : Olmesartan medoxomil (OLM, an anti-hypertensive agent administered orally has absolute bioavailability of only 26% due to the poor aqueous solubility (<7.75 μg/ml. The present investigation aimed at enhancing the oral bioavailability of OLM by improving its solubility and dissolution rate by preparing nanosuspensions. Materials and methods : The nanosuspensions of OLM were prepared using media milling technique followed by its lyophilization using mannitol as a cryoprotectant. Various formulation as well as process parameters were optimized in order to achieve desirable size and saturation solubility. Characterization of the prepared nanosuspension was done with respect to particle size, zeta potential, saturation solubility, dissolution rate, morphology study (TEM, in-vitro and exvivo drug diffusion study. Evaluation of the crystalline state before and after particle size reduction was done by differential scanning calorimetry (DSC and powder X-ray diffraction (PXRD. Results : The results indicated that the initial crystalline state is preserved following particle size reduction and that the saturation solubility, dissolution velocity and diffusion rate of the drug from the nanosuspension is significantly higher than that of the plain drug suspension as well as from the marketed tablet formulation. Conclusion : Nanosuspension seems to be a promising approach for bioavailability enhancement because of the simple method of its preparation and its universal applicability.

  5. The key importance of soy isoflavone bioavailability to understanding health benefits.

    Science.gov (United States)

    Larkin, Theresa; Price, William E; Astheimer, Lee

    2008-06-01

    Research over the past two decades has provided significant epidemiological and other evidence for the health benefits of the consumption of soy-based foods. A large number of dietary intervention studies have examined the effects of soy isoflavones on risk factors for cardiovascular disease and hormone-dependent cancers. However, these report large variability in outcome measures, very limited reproducibility between studies, and in some cases, controversy between the results of clinical trials using dietary soy or soy protein and isoflavone supplementation. This highlights a major gap in our understanding of soy isoflavone uptake, metabolism, distribution, and overall bioavailability. There are many potential factors that may influence bioavailability and a better knowledge is necessary to rationalize the inconsistencies in the intervention and clinical studies. This review focuses attention on our current state of knowledge in this area and highlights the importance of metabolism of the parent soy isoflavones and the critical role of gut microbiota on the bioavailability of these compounds and their metabolites.

  6. Bioequivalence and Bioavailability Clinical Trials: A Status Report from the National Institutes of Health ClinicalTrials.gov Registry

    OpenAIRE

    Stockmann, Chris; Spigarelli, Michael G.; Ampofo, Krow; Sherwin, Catherine MT

    2013-01-01

    Drug development is an expensive process that is marked by a high-failure rate. For this reason early stage bioequivalence and pharmacokinetic studies are essential in determining the fate of new drug products. In this study, we sought to systematically assess the current trends of ongoing and recently completed bioequivalence and bioavailability trials that have been registered within a national clinical trials registry. All bioequivalence and bioavailability studies registered in the United...

  7. Iron bioavailability of sweet potato and moringa leaves in comparision with leafy green vegetables commonly consumed in Ghana

    OpenAIRE

    2016-01-01

    Introduction: Iron deficiency anaemia (IDA) is a significant public health problem in Northern Ghana especially amongst women and children. Leafy green vegetables are major contributors to iron intake in this part of the world; poor iron bioavailability from these food sources may be part of the reason for the high prevalence of IDA. Evidence suggests that sweet potato and Moringa leaves might be better sources of bioavailable iron, compared with other leafy green vegetables, as both have hig...

  8. Application of isotope dilution method for measuring bioavailability of organic contaminants sorbed to dissolved organic matter (DOM)

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Moreno, Laura, E-mail: laura.delgado@eez.csic.es; Wu, Laosheng; Gan, Jay

    2015-08-15

    Natural waters such as surface water and sediment porewater invariably contain dissolved organic matter (DOM). Association of strongly hydrophobic contaminants (HOCs) with DOM leads to decreased toxicity and bioavailability, but bioavailability of DOM-sorbed HOCs is difficult to measure. Current methods to estimate bioavailability of HOCs in water are based on only the freely dissolved concentration (C{sub free}). The ignorance of the exchangeable fraction of HOCs sorbed on DOM may result in an underestimation of the toxicity potential of HOCs to aquatic organisms. Here we explore the applicability of an isotope dilution method (IDM) to measuring the desorption fraction of DOM-sorbed pyrene and bifenthrin and determining their exchangeable pool (E) as an approximation of bioavailability. E values, expressed as percentage of the total concentration, ranged between 0.80 and 0.92% for pyrene and 0.74 and 0.85% for bifenthrin, depending primarily on the amount of chemical in the freely dissolved form. However, between 34 and 78% of the DOM-sorbed pyrene was exchangeable. This fraction ranged between 23% and 82% for bifenthrin. The ability of IDM to predict bioavailability was further shown from a significant relationship (r{sup 2} > 0.72, P < 0.0001) between E and bioaccumulation into Daphnia magna. Therefore, IDM may be used to improve the bioavailability measurement and risk assessment of HOCs in aquatic systems.

  9. Formulation optimization of Docetaxel loaded self-emulsifying drug delivery system to enhance bioavailability and anti-tumor activity.

    Science.gov (United States)

    Valicherla, Guru R; Dave, Kandarp M; Syed, Anees A; Riyazuddin, Mohammed; Gupta, Anand P; Singh, Akhilesh; Wahajuddin; Mitra, Kalyan; Datta, Dipak; Gayen, Jiaur R

    2016-05-31

    Poor bioavailability of Docetaxel (DCT) arising due to its low aqueous solubility and permeability limits its clinical utility. The aim of the present study was to develop DCT loaded self-emulsified drug delivery systems (D-SEDDS) and evaluate its potential ability to improve the oral bioavailability and therapeutic efficacy of DCT. D-SEDDS were characterized for their in vitro antitumor activity, in situ single pass intestinal perfusion (SPIP), bioavailability, chylomicron flow blocking study and bio-distribution profile. The D-SEDDS were prepared using Capryol 90, Vitamin E TPGS, Gelucire 44/14 and Transcutol HP with a ratio of 32.7/29.4/8.3/29.6 using D-Optimal Mixture Design. The solubility of DCT was improved upto 50 mg/mL. The oral bioavailability of the D-SEDDS in rats (21.84 ± 3.12%) was increased by 3.19 fold than orally administered Taxotere (6.85 ± 1.82%). The enhanced bioavailability was probably due to increase in solubility and permeability. In SPIP, effective permeability of D-SEDDS was significantly higher than Taxotere. D-SEDDS showed 25 fold more in vitro cytotoxic activity compared to free DCT. Chylomicron flow blocking study and tissue distribution demonstrated the intestinal lymphatic transport of D-SEDDS and higher retention in tumor than Taxotere. The data suggests that D-SEDDS showed desired stability, enhanced oral bioavailability and in vitro antitumor efficacy.

  10. Preparation, characterization and relative bioavailability of oral elemene o/w microemulsion

    Directory of Open Access Journals (Sweden)

    Zhaowu Zeng

    2010-08-01

    Full Text Available Zhaowu Zeng1, Guanglin Zhou1, Xiaoli Wang2, Eric Zhijian Huang1, Xiaori Zhan1, Jun Liu1, Shuling Wang1, Anming Wang1, Haifeng Li1, Xiaolin Pei1, Tian Xie11Research Center for Biomedicine and Health, Hangzhou Normal University, Hangzhou, Zhejiang, China; 2Yichun University of Jiangxi Province, Yichun, Jiangxi, ChinaAbstract: The objective was to develop an elemene oil/water (o/w microemulsion and evaluate its characteristics and oral relative bioavailability in rats. Elemene was used as the oil phase and drug, polysorbate 80 as a surfactant along with ethanol, propylene glycol, and glycerol as the cosurfactants. The microemulsion was prepared by mixing method, or ultrasonication method in an ultrasonic bath. Its three-dimensional response surface diagram was drawn by Mathcad software. The microemulsion was characterized by visual observation, cross-polarized microscopy, size, zeta potential, acidity, viscosity, and surface tension measurement. The drug content and entrapment efficiency were determined by ultra fast liquid chromatography (UFLC and liquid surface method. Blood was drawn from rats at different time points after oral administration of an elemene microemulsion or a commercial elemene emulsion for measurement of the drug in plasma by UFLC to establish the pharmacokinetic parameters and relative bioavailability. The elemene microemulsion as a clarified and isotropic system containing 1% elemene (w/v, 5% ethanol (v/v, 15% propylene glycol (v/v, 15% glycerol (v/v, and 5% polysorbate 80 (w/v, was characterized as (57.7 ± 2.8 nm in size, 0.485 ± 0.032 in polydispersity index, (3.2 ± 0.4 mv in zeta potential, (5.19 ± 0.08 in pH, 6 mpa•s in viscosity, (31.8 ± 0.3 mN•m-1 in surface tension, (8.273 ± 0.018 mg•mL-1 in content of ß-elemene, and (99.81 ± 0.24% in average entrapment efficiency. The area under the concentration-time curves from 0 h to 24 h (AUC0→24h of the elemene microemulsion and commercial elemene emulsion were

  11. Enhancement of oral bioavailability of cyclosporine A: comparison of various nanoscale drug-delivery systems

    Directory of Open Access Journals (Sweden)

    Wang K

    2014-10-01

    Full Text Available Kai Wang,1–3 Jianping Qi,1 Tengfei Weng,1,2 Zhiqiang Tian,1 Yi Lu,1 Kaili Hu,4 Zongning Yin,2 Wei Wu1 1School of Pharmacy, Fudan University, Key Laboratory of Smart Drug Delivery of Ministry of Education, Shanghai, People’s Republic of China; 2West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, People’s Republic of China; 3Tropical Crops Genetic Resources Institute, Hainan Provincial Engineering Research Center for Blumea Balsamifera, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, People’s Republic of China; 4Murad Research Center for Modernized Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of ChinaAbstract: A variety of nanoscale delivery systems have been shown to enhance the oral absorption of poorly water-soluble and poorly permeable drugs. However, the performance of these systems has seldom been evaluated simultaneously. The aim of this study was to compare the bioavailability enhancement effect of lipid-based nanocarriers with poly(lactic-co-glycolic acid (PLGA nanoparticles (NPs to highlight the importance of the lipid composition, with cyclosporine A (CyA as a model drug. CyA-loaded PLGA NPs, nanostructured lipid carriers (NLCs, and self-microemulsifying drug-delivery systems (SMEDDS were prepared. The particle size of PLGA NPs (182.2±12.8 nm was larger than that of NLCs (89.7±9.0 nm and SMEDDS (26.9±1.9 nm. All vehicles are charged negatively. The entrapment efficiency of PLGA NPs and NLCs was 87.6%±1.6% and 80.3%±0.6%, respectively. In vitro release tests indicated that the cumulative release of CyA was lower than 4% from all vehicles, including Sandimmun Neoral®, according to the dialysis method. Both NLCs and SMEDDS showed high relative oral bioavailability, 111.8% and 73.6%, respectively, after oral gavage administration to beagle dogs, which was not statistically different from commercial Sandimmun Neoral®. However, PLGA NPs

  12. Biodisponibilidade de vitaminas lipossolúveis Bioavailability of fat-soluble vitamins

    Directory of Open Access Journals (Sweden)

    Denise Machado Mourão

    2005-08-01

    Full Text Available O termo biodisponibilidade representa a parte do nutriente ingerido que tem o potencial de suprir as demandas fisiológicas em tecidos alvos; por definição, não corresponde, na maioria das vezes, à quantidade ingerida. Apesar da concordância entre alguns pesquisadores no que se refere ao conceito de biodisponibilidade, vários termos são comumente utilizados em trabalhos científicos como sinônimos desse, em função das peculiaridades dos métodos empregados na sua determinação. Estudos de balanço, relação dose-efeito e uso de isótopos são alguns dos métodos mais comumente utilizados para determinar a biodisponibilidade de vitaminas. Tais metodologias, além de avaliar a biodisponibilidade do nutriente, devem tanto quanto possível procurar elucidar ou levar em consideração os fatores que interferem na sua absorção e utilização. Dentre esses fatores, estão a interação com outros nutrientes ou componentes da dieta e as condições fisiológicas dos organismos submetidos ao estudo. As vitaminas lipossolúveis, devido ao seu metabolismo complexo, diversidade funcional e mecanismo de absorção relacionado a lipoproteínas, apresentam alguns problemas específicos no que se refere à avaliação de sua biodisponibilidade em alimentos ou dietas, necessitando, por ocasião dos ensaios, de um criterioso planejamento e análise de resultados. Dessa forma, ressaltaram-se, nesta revisão, alguns aspectos importantes com relação à biodisponibilidade das vitaminas lipossolúveis, como: diversidade de termos usados, metodologia para avaliação, fatores que interferem na absorção e utilização, entre outros, visto que a avaliação da biodisponibilidade de algumas vitaminas lipossolúveis ainda não possui métodos validados, gerando uma grande variação nos resultados obtidos nas pesquisas realizadas nesta área.The term bioavailability represents the part of the nutrient ingested that has the potential to supply the

  13. Importance of suspended sediment (SPS) composition and grain size in the bioavailability of SPS-associated pyrene to Daphnia magna.

    Science.gov (United States)

    Xia, Xinghui; Zhang, Xiaotian; Zhou, Dong; Bao, Yimeng; Li, Husheng; Zhai, Yawei

    2016-07-01

    Hydrophobic organic compounds (HOCs) tend to associate with suspended sediment (SPS) in aquatic environments; the composition and grain size of SPS will affect the bioavailability of SPS-associated HOCs. However, the bioavailability of HOCs sorbed on SPS with different compositions and grain sizes is not well understood. In this work, passive dosing devices were made to control the freely dissolved concentration of pyrene, a typical HOC, in the exposure systems. The effect of pyrene associated with amorphous organic carbon (AOC), black carbon (BC), and minerals of SPS with grain sizes of 0-50 μm and 50-100 μm on the immobilization and enzymatic activities of Daphnia magna was investigated to quantify the bioavailability of pyrene sorbed on SPS with different grain sizes and compositions. The results showed that the contribution of AOC-, BC-, and mineral-associated pyrene to the total bioavailability of SPS-associated pyrene was approximately 50%-60%, 10%-29%, and 20%-30%, respectively. The bioavailable fraction of pyrene sorbed on the three components of SPS was ordered as AOC (22.4%-67.3%) > minerals (20.1%-46.0%) > BC (9.11%-16.8%), and the bioavailable fraction sorbed on SPS of 50-100 μm grain size was higher than those of 0-50 μm grain size. This is because the SPS grain size will affect the ingestion of SPS and the SPS composition will affect the desorption of SPS-associated pyrene in Daphnia magna. According to the results obtained in this study, a model has been developed to calculate the bioavailability of HOCs to aquatic organisms in natural waters considering both SPS grain size and composition.

  14. Niosomal carriers enhance oral bioavailability of carvedilol: effects of bile salt-enriched vesicles and carrier surface charge.

    Science.gov (United States)

    Arzani, Gelareh; Haeri, Azadeh; Daeihamed, Marjan; Bakhtiari-Kaboutaraki, Hamid; Dadashzadeh, Simin

    2015-01-01

    Carvedilol (CRV) is an antihypertensive drug with both alpha and beta receptor blocking activity used to preclude angina and cardiac arrhythmias. To overcome the low, variable oral bioavailability of CRV, niosomal formulations were prepared and characterized: plain niosomes (without bile salts), bile salt-enriched niosomes (bilosomes containing various percentages of sodium cholate or sodium taurocholate), and charged niosomes (negative, containing dicetyl phosphate and positive, containing hexadecyl trimethyl ammonium bromide). All formulations were characterized in terms of encapsulation efficiency, size, zeta potential, release profile, stability, and morphology. Various formulations were administered orally to ten groups of Wistar rats (n=6 per group). The plasma levels of CRV were measured by a validated high-performance liquid chromatography (HPLC) method and pharmacokinetic properties of different formulations were characterized. Contribution of lymphatic transport to the oral bioavailability of niosomes was also investigated using a chylomicron flow-blocking approach. Of the bile salt-enriched vesicles examined, bilosomes containing 20% sodium cholate (F2) and 30% sodium taurocholate (F5) appeared to give the greatest enhancement of intestinal absorption. The relative bioavailability of F2 and F5 formulations to the suspension was estimated to be 1.84 and 1.64, respectively. With regard to charged niosomes, the peak plasma concentrations (Cmax) of CRV for positively (F7) and negatively charged formulations (F10) were approximately 2.3- and 1.7-fold higher than after a suspension. Bioavailability studies also revealed a significant increase in extent of drug absorption from charged vesicles. Tissue histology revealed no signs of inflammation or damage. The study proved that the type and concentration of bile salts as well as carrier surface charge had great influences on oral bioavailability of niosomes. Blocking the lymphatic absorption pathway

  15. Enhanced oral bioavailability of fenofibrate using polymeric nanoparticulated systems: physicochemical characterization and in vivo investigation

    Directory of Open Access Journals (Sweden)

    Yousaf AM

    2015-03-01

    Full Text Available Abid Mehmood Yousaf,1 Dong Wuk Kim,1 Yu-Kyoung Oh,2 Chul Soon Yong,3 Jong Oh Kim,3 Han-Gon Choi11College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, 2College of Pharmacy, Seoul National University, Seoul, 3College of Pharmacy, Yeungnam University, Gyongsan, South KoreaBackground: The intention of this research was to prepare and compare various solubility-enhancing nanoparticulated systems in order to select a nanoparticulated formulation with the most improved oral bioavailability of poorly water-soluble fenofibrate.Methods: The most appropriate excipients for different nanoparticulated preparations were selected by determining the drug solubility in 1% (w/v aqueous solutions of each carrier. The polyvinylpyrrolidone (PVP nanospheres, hydroxypropyl-β-cyclodextrin (HP-β-CD nanocorpuscles, and gelatin nanocapsules were formulated as fenofibrate/PVP/sodium lauryl sulfate (SLS, fenofibrate/HP-β-CD, and fenofibrate/gelatin at the optimized weight ratios of 2.5:4.5:1, 1:4, and 1:8, respectively. The three solid-state products were achieved using the solvent-evaporation method through the spray-drying technique. The physicochemical characterization of these nanoparticles was accomplished by powder X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Their physicochemical properties, aqueous solubility, dissolution rate, and pharmacokinetics in rats were investigated in comparison with the drug powder.Results: Among the tested carriers, PVP, HP-β-CD, gelatin, and SLS showed better solubility and were selected as the most appropriate constituents for various nanoparticulated systems. All of the formulations significantly improved the aqueous solubility, dissolution rate, and oral bioavailability of fenofibrate compared to the drug powder. The drug was present in the amorphous form in HP-β-CD nanocorpuscles; however, in

  16. The study of bioavailability and bioequivalence of oseltamivir in Chinese health volunteers

    Institute of Scientific and Technical Information of China (English)

    LI Jing-lai; CUI Meng-cun; WANG Xiao-ying; QIAO Jian-zhong; YUAN Su-lan; ZHANG Zhen-qing; RUAN Jin-xiu; ZHONG Wu; LI Song

    2008-01-01

    Objective To evaluate the bioavailability and bioequivalence of oseltamivir capsule in Chinese health male volunteers. Methods A randomized, two period, two treatment, two sequence crossover bioequivalence trial was designed, 24 Chinese health volunteers were randomly divided into two groups, each group was orally given single dose oseltamivir phosphate (tamifla) or AMMS 607 capsule. The active metabolite oseltamivir carboxylate of oseltamivir in the plasma were determined by liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method. The pharmacokinetics parameters and relative bioavailability were calculated to evaluate the bioequivalence of AMMS 607 and tamifla. Results Cmax of the AMMS 607 and tamifla were 602.07±153.27 ng·mL-1 and 620.09±132.39 ng·mL-1 respectively; tmax were 4.2± 1.1 h and 4.8±1.0 h; t1/2β were 6.60±0.87 h and 6.61±0.83 h;MRT were 10.00±1.77 h and 10.40 ±1.62 h; AUC0-24 were 6285.88±1083.66 ng·h·mL-1 and 6546.01±1199.32 ng·h·mL-1; Compared with the reference of tamifla capsule, the bioavailability F0-tn of AMMS 607 capsule was 99.5±27.7 %. The main pharmacokinetics parameters of AUC0-24, Cmax and Tmax showed no statistically significant difference between the two capsules. Conclusions The AMMS 607 capsule and tamifla capsule are bioequivalent.

  17. Sublingual fast dissolving niosomal films for enhanced bioavailability and prolonged effect of metoprolol tartrate

    Science.gov (United States)

    Allam, Ayat; Fetih, Gihan

    2016-01-01

    The aim of the present work was to prepare and evaluate sublingual fast dissolving films containing metoprolol tartrate-loaded niosomes. Niosomes were utilized to allow for prolonged release of the drug, whereas the films were used to increase the drug’s bioavailability via the sublingual route. Niosomes were prepared using span 60 and cholesterol at different drug to surfactant ratios. The niosomes were characterized for size, zeta-potential, and entrapment efficiency. The selected niosomal formulation was incorporated into polymeric films using hydroxypropyl methyl cellulose E15 and methyl cellulose as film-forming polymers and Avicel as superdisintegrant. The physical characteristics (appearance, texture, pH, uniformity of weight and thickness, disintegration time, and palatability) of the prepared films were studied, in addition to evaluating the in vitro drug release, stability, and in vivo pharmacokinetics in rabbits. The release of the drug from the medicated film was fast (99.9% of the drug was released within 30 minutes), while the drug loaded into the niosomes, either incorporated into the film or not, showed only 22.85% drug release within the same time. The selected sublingual film showed significantly higher rate of drug absorption and higher drug plasma levels compared with that of commercial oral tablet. The plasma levels remained detectable for 24 hours following sublingual administration, compared with only 12 hours after administration of the oral tablet. In addition, the absolute bioavailability of the drug (ie, relative to intravenous administration) following sublingual administration was found to be significantly higher (91.06%±13.28%), as compared with that after oral tablet administration (39.37%±11.4%). These results indicate that the fast dissolving niosomal film could be a promising delivery system to enhance the bioavailability and prolong the therapeutic effect of metoprolol tartrate. PMID:27536063

  18. Influence of dispersants on petroleum bioavailability in a marine food chain

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, M.; Tjeerdema, R. [Univ. of California, Santa Cruz, CA (United States). Dept. of Chemistry and Biochemistry; Sowby, M. [California Dept. of Fish and Game, Sacramento, CA (United States)

    1995-12-31

    When crude oil is accidentally released into the ocean it threatens many levels of marine life. Intervention, in the form of chemical dispersing agents, may alter the normal behavior of petroleum hydrocarbons (PH) by increasing their functional water solubility and the extent of their exposure to sub-surface marine organisms. Further, the dispersing agent may modify bioavailability as a result of altered interactions between dispersed PH droplets and organismal cell membranes, To date, little information exists on the sub-lethal effects of dispersants and factors modifying their role in the bioavailability and disposition of PH in marine food chains. The objective of the current research was to determine the impact of dispersing agents on PH bioavailability to primary levels of a marine food chain. Uptake, bioaccumulation, deputation, and metabolic transformation of a model PH, {sup 14}C-naphthalene, were measured and compared for dispersed Prudhoe Bay Crude Oil (PBCO) vs. undispersed preparations of the water-accommodated fractions (WAF) of PBCO at two salinities (22 and 34 ppt) employing Isochrysis galbana, a primary producer, and Brachionus plicatilis, a primary consumer. Fractionation and identification of metabolites was done by HPLC co-chromatography with analytical standards, and quantitation was done by liquid scintillation counting. GC-FID characterization of WAF and dispersed oil preparations shows higher concentrations of petroleum hydrocarbons and a greater number of individual constituents in the dispersed oil preparations. However, short term (eight hour) and long term (two week) static exposure studies indicate the uptake of{sup 14}C-naphthalene from WAF preparations is inhibited by up to 50% from dispersed oil preparations. Results of comparative static and flow-through chamber exposure studies will be presented.

  19. Bioavailability and biodistribution of differently charged polystyrene nanoparticles upon oral exposure in rats

    Energy Technology Data Exchange (ETDEWEB)

    Walczak, Agata P. [Wageningen University, Division of Toxicology (Netherlands); Hendriksen, Peter J. M. [RIKILT Wageningen UR (Netherlands); Woutersen, Ruud A. [TNO Earth, Life and Social Sciences (Netherlands); Zande, Meike van der; Undas, Anna K.; Helsdingen, Richard [RIKILT Wageningen UR (Netherlands); Berg, Hans H. J. van den; Rietjens, Ivonne M. C. M. [Wageningen University, Division of Toxicology (Netherlands); Bouwmeester, Hans, E-mail: hans.bouwmeester@wur.nl [RIKILT Wageningen UR (Netherlands)

    2015-05-15

    The likelihood of oral exposure to nanoparticles (NPs) is increasing, and it is necessary to evaluate the oral bioavailability of NPs. In vitro approaches could help reducing animal studies, but validation against in vivo studies is essential. Previously, we assessed the translocation of 50 nm polystyrene NPs of different charges (neutral, positive and negative) using a Caco-2/HT29-MTX in vitro intestinal translocation model. The NPs translocated in a surface charge-dependent manner. The present study aimed to validate this in vitro intestinal model by an in vivo study. For this, rats were orally exposed to a single dose of these polystyrene NPs and the uptake in organs was determined. A negatively charged NP was taken up more than other NPs, with the highest amounts in kidney (37.4 µg/g tissue), heart (52.8 µg/g tissue), stomach wall (98.3 µg/g tissue) and small intestinal wall (94.4 µg/g tissue). This partly confirms our in vitro findings, where the same NPs translocated to the highest extent. The estimated bioavailability of different types of NPs ranged from 0.2 to 1.7 % in vivo, which was much lower than in vitro (1.6–12.3 %). Therefore, the integrated in vitro model cannot be used for a direct prediction of the bioavailability of orally administered NPs. However, the model can be used for prioritizing NPs before further in vivo testing for risk assessment.

  20. Study on Plasma Concentration and Bioavailability of Wogonin in Beagle's Dogs

    Institute of Scientific and Technical Information of China (English)

    LI Jian-chun; CHEN Fei-hu; DONG Hai-jun; GAO Shu

    2011-01-01

    Objective To develop an LC-MS/MS method for determining the concentration of wogonin in dog plasma and investigate the pharmacokinetics and bioavailability by different administrations of wogonin in Beagle's dogs. Methods LC-MS/MS was employed in determining the concentration of wogonin with the selected ion monitoring model after liquid-liquid extraction with ethyl acetate of dog plasma samples. The lower limit of quantification was 0.105 μg/L. Target ions were at m/z 285.0→270.0 for wogonin and 373.3→305.3 for finasteride. In a randomized, self-control, and cross-over study, six male Beagle's dogs were treated with different administration methods in three test periods. Pharmacokinetic parameters were calculated with DAS software (Ver. 2.0). Results The calibration curve was linear in the range of 0.105-107.36 μg/L for wogonin in dog plasma samples. The main pharmacokinetic parameters of ig administration (native drug of 15 mg/kg and solution preparation of 5 mg/kg) and iv route were as follows: Cmax (2.5 ± 1.1), (7.9 ± 3.3), and (6838.7 ± 1322.1) μg/L, tmax (0.7 ± 0.3) and (0.3 ± 0.2) h for the both former, AUC0-1 (7.1 ± 2.0), (21.0 ± 3.2), and (629.7 ±111.8) μg·h/L. The absolute bioavailability of native and solution of wogonin were (0.59 ± 0.35)% and (3.65 ± 2.00)%, respectively. Conclusion The validated method is convenient, sensitive, and specific, and the improvement of wogonin solubility could remarkably increase the absolute bioavailability.

  1. Sublingual fast dissolving niosomal films for enhanced bioavailability and prolonged effect of metoprolol tartrate

    Directory of Open Access Journals (Sweden)

    Allam A

    2016-08-01

    Full Text Available Ayat Allam, Gihan Fetih Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, Egypt Abstract: The aim of the present work was to prepare and evaluate sublingual fast dissolving films containing metoprolol tartrate-loaded niosomes. Niosomes were utilized to allow for prolonged release of the drug, whereas the films were used to increase the drug’s bioavailability via the sublingual route. Niosomes were prepared using span 60 and cholesterol at different drug to surfactant ratios. The niosomes were characterized for size, zeta-potential, and entrapment efficiency. The selected niosomal formulation was incorporated into polymeric films using hydroxypropyl methyl cellulose E15 and methyl cellulose as film-forming polymers and Avicel as superdisintegrant. The physical characteristics (appearance, texture, pH, uniformity of weight and thickness, disintegration time, and palatability of the prepared films were studied, in addition to evaluating the in vitro drug release, stability, and in vivo pharmacokinetics in rabbits. The release of the drug from the medicated film was fast (99.9% of the drug was released within 30 minutes, while the drug loaded into the niosomes, either incorporated into the film or not, showed only 22.85% drug release within the same time. The selected sublingual film showed significantly higher rate of drug absorption and higher drug plasma levels compared with that of commercial oral tablet. The plasma levels remained detectable for 24 hours following sublingual administration, compared with only 12 hours after administration of the oral tablet. In addition, the absolute bioavailability of the drug (ie, relative to intravenous administration following sublingual administration was found to be significantly higher (91.06%±13.28%, as compared with that after oral tablet administration (39.37%±11.4%. These results indicate that the fast dissolving niosomal film could be a promising delivery system to

  2. Chitosan-based nanoparticles for improved anticancer efficacy and bioavailability of mifepristone

    Directory of Open Access Journals (Sweden)

    Huijuan Zhang

    2016-11-01

    Full Text Available In addition to its well-known abortifacient effect, mifepristone (MIF has been used as an anticancer drug for various cancers in many studies with an in-depth understanding of the mechanism of action. However, application of MIF is limited by its poor water solubility and low oral bioavailability. In this work, we developed a drug delivery system based on chitosan nanoparticles (CNs to improve its bioavailability and anticancer activity. The MIF-loaded chitosan nanoparticles (MCNs were prepared by convenient ionic gelation techniques between chitosan (Cs and tripolyphosphate (TPP. The preparation conditions, including Cs concentration, TPP concentration, Cs/MIF mass ratio, and pH value of the TPP solution, were optimized to gain better encapsulation efficiency (EE and drug loading capacity (DL. MCNs prepared with the optimum conditions resulted in spherical particles with an average size of 200 nm. FTIR and XRD spectra verified that MIF was successfully encapsulated in CNs. The EE and DL of MCNs determined by HPLC were 86.6% and 43.3%, respectively. The in vitro release kinetics demonstrated that MIF was released from CNs in a sustained-release manner. Compared with free MIF, MCNs demonstrated increased anticancer activity in several cancer cell lines. Pharmacokinetic studies in male rats that were orally administered MCNs showed a 3.2-fold increase in the area under the curve from 0 to 24 h compared with free MIF. These results demonstrated that MCNs could be developed as a potential delivery system for MIF to improve its anticancer activity and bioavailability.

  3. Cubic phase nanoparticles for sustained release of ibuprofen formulation characterization and enhanced bioavailability study

    Directory of Open Access Journals (Sweden)

    Dian L

    2013-02-01

    Full Text Available Linghui Dian,1,2,* Zhiwen Yang,3,* Feng Li,1 Zhouhua Wang,1 Xin Pan,1 Xinsheng Peng,2 Xintian Huang,1 Zhefei Guo,1 Guilan Quan,1 Xuan Shi,1 Bao Chen,1 Ge Li,4 Chuanbin Wu1,41School of Pharmaceutical Sciences, Sun Yat-Sen University, University Town, Guangzhou, People’s Republic of China; 2School of Pharmaceutical Sciences, Guangdong Medical College, Dongguan, People’s Republic of China; 3Department of Gastroenterology, Songjiang Branch of the Affiliated First People’s Hospital of Shanghai Jiaotong University, Shanghai, People’s Republic of China; 4Guangdong Research Center for Drug Delivery Systems, Guangzhou, People’s Republic of China*These authors contributed equally to this workAbstract: In order to improve the oral bioavailability of ibuprofen, ibuprofen-loaded cubic nanoparticles were prepared as a delivery system for aqueous formulations. The cubic inner structure was verified by cryogenic transmission electron microscopy. With an encapsulation efficiency greater than 85%, the ibuprofen-loaded cubic nanoparticles had a narrow size distribution around a mean size of 238 nm. Differential scanning calorimetry and X-ray diffraction determined that ibuprofen was in an amorphous and molecular form within the lipid matrix. The in vitro release of ibuprofen from cubic nanoparticles was greater than 80% at 24 hours, showing sustained characteristics. The pharmacokinetic study in beagle dogs showed improved absorption of ibuprofen from cubic nanoparticles compared to that of pure ibuprofen, with evidence of a longer half-life and a relative oral bioavailability of 222% (P < 0.05. The ibuprofen-loaded cubic nanoparticles provide a promising carrier candidate with an efficient drug delivery for therapeutic treatment.Keywords: ibuprofen, cubic nanoparticles, oral drug delivery, bioavailability

  4. Enhanced bioavailability of nerve growth factor with phytantriol lipid-based crystalline nanoparticles in cochlea

    Directory of Open Access Journals (Sweden)

    Bu M

    2015-11-01

    Full Text Available Meng Bu,1,2 Jingling Tang,3 Yinghui Wei,4 Yanhui Sun,1 Xinyu Wang,1 Linhua Wu,2 Hongzhuo Liu1 1School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, People’s Republic of China; 2Department of Pharmacy, the Second Affiliated Hospital, 3School of Pharmacy, Harbin Medical University, Harbin, People’s Republic of China; 4College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, People’s Republic of China Purpose: Supplementation of exogenous nerve growth factor (NGF into the cochlea of deafened animals rescues spiral ganglion cells from degeneration. However, a safe and potent delivery of therapeutic proteins, such as NGF, to spiral ganglion cells remains one of the greatest challenges. This study presents the development of self-assembled cubic lipid-based crystalline nanoparticles to enhance inner ear bioavailability of bioactive NGF via a round window membrane route.Methods: A novel nanocarrier-entrapped NGF was developed based on phytantriol by a liquid precursor dilution, with Pluronic® F127 and propylene glycol as the surfactant and solubilizer, respectively. Upon dilution of the liquid lipid precursors, monodispersed submicron-sized particles with a slight negative charge formed spontaneously.Results: Biological activity of entrapped NGF was assessed using pheochromocytoma cells with NGF-loaded reservoirs to induce significant neuronal outgrowth, similar to that seen in free NGF-treated controls. Finally, a 3.28-fold increase in inner ear bioavailability was observed after administration of phytantriol lipid-based crystalline nanoparticles as compared to free drug, contributing to an enhanced drug permeability of the round window membrane. Conclusion: Data presented here demonstrate the potential of lipid-based crystalline nanoparticles to improve the outcomes of patients bearing cochlear implants. Keywords: nerve growth factor, lipid-based crystalline nanoparticles, PC12 cells, inner ear drug

  5. Development of olmesartan medoxomil optimized nanosuspension using the Box-Behnken design to improve oral bioavailability.

    Science.gov (United States)

    Nagaraj, K; Narendar, D; Kishan, V

    2017-03-27

    The aim of the present investigation was to enhance the oral bioavailability of olmesartan medoxomil by improving its solubility and dissolution rate by preparing nanosuspension (OM-NS), using the Box-Behnken design. In this, four factors were evaluated at three levels. Independent variables include: concentration of drug (X1), concentration of surfactant (X2), concentration of polymer (X3) and number of homogenization cycles (X4). Based on preliminary studies, the size (Y1), zeta potential (ZP) (Y2) and % drug release at 5 min (Y3) were chosen as dependent responses. OM-NS was prepared by high pressure homogenization method. The size, PDI, ZP, assay, in vitro release and morphology of OM-NS were characterized. Further, the pharmacokinetic (PK) behavior of OM-NS was evaluated in male wistar rats. Statistically optimized OM-NS formulation exhibited mean particle size of 492 nm, ZP of -27.9 mV and 99.29% release in 5 min. OM-NS showed more than four times increase in its solubility than pure OM. DSC and XRD analyses indicated that the drug incorporated into OM-NS was in amorphous form. The morphology of OM-NS was found to be nearly spherical with high dispersity by scanning electron microscopic studies. The PK results showed that OM lyophilized nanosuspension (NS) exhibited improved PK properties compared to coarse powder suspension and marketed tablet powder suspension (TS). Oral bioavailability of lyophilized NS was increased by 2.45 and 2.25 folds when compared to marketed TS and coarse powder suspension, respectively. Results of this study lead to conclusion that NS approach was effective in preparing OM formulations with enhanced dissolution and improved oral bioavailability.

  6. Brain distribution and bioavailability of elacridar after different routes of administration in the mouse.

    Science.gov (United States)

    Sane, Ramola; Agarwal, Sagar; Elmquist, William F

    2012-08-01

    The objective of this study was to determine the bioavailability and disposition of elacridar (GF120918; N-(4-(2-(1,2,3,4-tetrahydro-6,7-dimethoxy-2-isoquinolinyl)ethyl)phenyl)-9,10-dihydro-5-methoxy-9-oxo-4-acridine carboxamide) in plasma and brain after various routes of administration in the mouse. Elacridar is a potent inhibitor of P-glycoprotein and breast cancer resistance protein and has been used to examine the influence of these efflux transporters on drug distribution to brain. Friend leukemia virus strain B mice were administered 100 mg/kg elacridar either orally or intraperitoneally. The absolute bioavailability of elacridar after oral or intraperitoneal dosing was determined with respect to an intravenous dose of 2.5 mg/kg. At these doses, the absolute bioavailability was 0.22 for oral administration and 0.01 for intraperitoneal administration. The terminal half-life of elacridar was approximately 4 h after intraperitoneal and intravenous administration and nearly 20 h after oral dosing. The brain-to-plasma partition coefficient (Kp,brain) of elacridar increased as plasma exposure increased, suggesting saturation of the efflux transporters at the blood-brain barrier. The Kp,brain after intravenous, intraperitoneal, and oral dosing was 0.82, 0.43, and 4.31, respectively. The low aqueous solubility and high lipophilicity of elacridar result in poor oral absorption, most likely dissolution-rate-limited. These results illustrate the importance of the route of administration and the resultant plasma exposure in achieving effective plasma and brain concentrations of elacridar and can be used as a guide for future studies involving elacridar administration and in developing formulation strategies to overcome the poor absorption.

  7. Approaches to improve the oral bioavailability and effects of novel anticancer drugs berberine and betulinic acid.

    Directory of Open Access Journals (Sweden)

    Chandraiah Godugu

    Full Text Available The poor bioavailability of Berberine (BBR and Betulinic acid (BA limits the development of these promising anticancer agents for clinical use. In the current study, BBR and BA in spray dried (SD mucoadhesive microparticle formulations were prepared.A patented dual channel spray gun technology established in our laboratory was used for both formulations. Gastrointestinal (GI permeability studies were carried out using Caco-2 cell monolayer grown in in-vitro system. The oral bioavailability and pharmacokinetic profile of SD formulations were studied in Sprague Dawley rats. A549 orthotopic and H1650 metastatic NSCLC models were utilized for the anticancer evaluations.Pharmacokinetic studies demonstrated that BBR and BA SD formulations resulted in 3.46 and 3.90 fold respectively, significant increase in plasma Cmax concentrations. AUC levels were increased by 6.98 and 7.41 fold in BBR and BA SD formulations, respectively. Compared to untreated controls groups, 49.8 & 53.4% decrease in the tumor volumes was observed in SD formulation groups of BBR and BA, respectively. Molecular studies done on excised tumor (A549 tissue suggested that BBR in SD form resulted in a significant decrease in the survivin, Bcl-2, cyclin D1, MMP-9, HIF-1α, VEGF and CD31 expressions. Cleaved caspase 3, p53 and TUNEL expressions were increased in SD formulations. The RT-PCR analysis on H1650 tumor tissue suggested that p38, Phospho-JNK, Bax, BAD, cleaved caspase 3&8 mRNA expressions were significantly increased in BA SD formulations. Chronic administration of BBR and BA SD formulations did not show any toxicity.Due to significant increase in oral bioavailability and superior anticancer effects, our results suggest that spray drying is a superior alternative formulation approach for oral delivery of BBR and BA.

  8. Effects of standard humic materials on relative bioavailability of NDL-PCBs in juvenile swine.

    Directory of Open Access Journals (Sweden)

    Matthieu Delannoy

    Full Text Available Young children with their hand-to-mouth activity may be exposed to contaminated soils. However few studies assessing exposure of organic compounds sequestrated in soil were realized. The present study explores the impact of different organic matters on retention of NDL-PCBs during digestive processes using commercial humic substances in a close digestive model of children: the piglet. Six artificial soils were used. One standard soil, devoid of organic matter, and five amended versions of this standard soil with either fulvic acid, humic acid, Sphagnum peat, activated carbon or a mix of Sphagnum peat and activated carbon (95∶5 (SPAC were prepared. In order to compare the different treatments, we use spiked oil and negative control animals. Forty male piglets were randomly distributed in 7 contaminated and one control groups (n = 5 for each group. During 10 days, the piglets were fed artificial soil or a corn oil spiked with 19,200 ng of Aroclor 1254 per g of dry matter (6,000 ng.g⁻¹ of NDL-PCBs to achieve an exposure dose of 1,200 ng NDL-PCBs.Kg⁻¹ of body weight per day. NDL-PCBs in adipose tissue were analyzed by GC-MS. Fulvic acid reduced slightly the bioavailability of NDL-PCBs compared to oil. Humic acid and Sphagnum peat reduced it significantly higher whereas activated carbon reduced the most. Piglets exposed to soil containing both activated carbon and Shagnum peat exhibited a lower reduction than soil with only activated carbon. Therefore, treatment groups are ordered by decreasing value of relative bioavailability as following: oil ≥ fulvic acid>Sphagnum peat ≥ Sphagnum peat and activated carbon ≥ Humic acid>>activated carbon. This suggests competition between Sphagnum peat and activated carbon. The present study highlights that quality of organic matter does have a significant effect on bioavailability of sequestrated organic compounds.

  9. A Randomised Cross-Over Pharmacokinetic Bioavailability Study of Synthetic versus Kiwifruit-Derived Vitamin C

    Directory of Open Access Journals (Sweden)

    Margreet C. M. Vissers

    2013-11-01

    Full Text Available Kiwifruit are a rich source of vitamin C and also contain numerous phytochemicals, such as flavonoids, which may influence the bioavailability of kiwifruit-derived vitamin C. The aim of this study was to compare the relative bioavailability of synthetic versus kiwifruit-derived vitamin C using a randomised cross-over pharmacokinetic study design. Nine non-smoking males (aged 18–35 years received either a chewable tablet (200 mg vitamin C or the equivalent dose from gold kiwifruit (Actinidia chinensis var. Sungold. Fasting blood and urine were collected half hourly to hourly over the eight hours following intervention. The ascorbate content of the plasma and urine was determined using HPLC with electrochemical detection. Plasma ascorbate levels increased from 0.5 h after the intervention (P = 0.008. No significant differences in the plasma time-concentration curves were observed between the two interventions (P = 0.645. An estimate of the total increase in plasma ascorbate indicated complete uptake of the ingested vitamin C tablet and kiwifruit-derived vitamin C. There was an increase in urinary ascorbate excretion, relative to urinary creatinine, from two hours post intervention (P < 0.001. There was also a significant difference between the two interventions, with enhanced ascorbate excretion observed in the kiwifruit group (P = 0.016. Urinary excretion was calculated as ~40% and ~50% of the ingested dose from the vitamin C tablet and kiwifruit arms, respectively. Overall, our pharmacokinetic study has shown comparable relative bioavailability of kiwifruit-derived vitamin C and synthetic vitamin C.

  10. Strategies to Quantify and Decrease Mercury Bioavailability and Methylation Potential in the Aquatic Environment

    Science.gov (United States)

    Hsu-Kim, H.; Deshusses, M.; Elias, D. A.

    2015-12-01

    Mercury (Hg) contamination in aquatic environments is a concern due to the production of monomethylmercury (MeHg), the highly bioaccumulative form that can impart neurotoxic effects to wildlife and humans. One strategy for remediation is to minimize MeHg production by anaerobic microorganisms that are prevalent in benthic settings. However, the factors that influence MeHg production and, in particular, the bioavailability of inorganic Hg for methylating microorganisms are poorly understood and difficult to quantify. This presentation will discuss the application of a thiol-based selective leaching assay to quantify the bioavailable fraction of Hg in sediments. This leaching assay involves quantification of leachable Hg concentrations in samples that are exposed to anoxic solutions containing glutathione (GSH). This thiol-based approach was chosen because cellular uptake and methylation of Hg by methylating bacteria are known to increase with the addition of GSH to cultures. This assay was applied to sediment-slurry microcosms that were amended with multiple types of inorganic Hg (dissolved Hg2+, Hg-sorbed to FeS, nanoparticulate HgS, microcrystalline HgS) that are known to span a range of bioavailability and methylation potential. The results demonstrated that the GSH-leachable Hg concentration correlated with MeHg production in cultures and microcosms. Methylation potential did not correlate to the concentration of Hg in the filtered aqueous fraction in the microcosm (i.e., passable though 0.2 um filters). These results suggest that a portion of the particle-bound Hg is available for methylation in a way that cannot be assessed by conventional filtration methods. The results of this work will be discussed in the context of management and in-situ remediation of contaminated sediments.

  11. QbD based development of proliposome of lopinavir for improved oral bioavailability.

    Science.gov (United States)

    Patel, Grishma M; Shelat, Pragna K; Lalwani, Anita N

    2016-08-30

    Aim of present work was to apply quality by design (QbD) principles for the development of proliposome of poorly soluble lopinavir (LPV). The patient-centric quality target product profile (QTPP) was defined and critical quality attributes (CQAs) earmarked. Risk assessment studies were carried out to identify the probable risks affecting the CQAs of the product. On the basis of preliminary study, lipid:drug ratio and amount of carrier were selected as critical material attributes (CMAs) and were optimized by face centered central composite design. Liposome vesicle size, drug entrapment efficiency and % drug release after 60min were selected as CQAs and mathematical relationship between CQAs and CMAs was derived using multiple linear regression analysis. Optimum composition of CMAs, identified using numerical optimization and desirability function, demonstrated excellent entrapment efficiency (>90%), drug release characteristics (>95% in 60min) and had vesicle size of 659.7±23.1nm. Solid state characterization studies (Differential Scanning Calorimetry, scanning electron microscopy and X-ray diffraction) were performed for optimized proliposome, suggested transformation of crystalline to amorphous form. Oral bioavailability study in Wistar rats revealed that LPV proliposome exhibited 2.24 and 1.16 fold higher bioavailability than pure LPV and available commercial formulation of LPV/RTV (lopinavir+ritonavir), respectively. Stability study of the optimized LPV loaded proliposome was performed as per ICH guideline and was found to be stable for period of 6months. Overall results of the study indicate that the proliposome offers advantages of enhanced oral bioavailability for poorly soluble LPV.

  12. The comparison of different daidzein-PLGA nanoparticles in increasing its oral bioavailability

    Directory of Open Access Journals (Sweden)

    Ma YR

    2012-02-01

    Full Text Available Yiran Ma, Xinyi Zhao, Jian Li, Qi ShenSchool of Pharmacy, Shanghai Jiao Tong University, Shanghai, ChinaAbstract: The aim of this research was to increase the oral bioavailability of daidzein by the formulations of poly(lactic-co-glycolic acid (PLGA nanoparticles loaded with daidzein. Amongst the various traditional and novel techniques of preparing daidzein-loaded PLGA nanoparticles, daidzein-loaded phospholipid complexes PLGA nanoparticles and daidzein-loaded cyclodextrin inclusion complexes PLGA nanoparticles were selected. The average drug entrapment efficiency, particle size, and zeta potential of daidzein-loaded phospholipid complexes PLGA nanoparticles and daidzein-loaded cyclodextrin inclusion complexes PLGA nanoparticles were 81.9% ± 5%, 309.2 ± 14.0 nm, -32.14 ± 2.53 mV and 83.2% ± 7.2%, 323.2 ± 4.8 nm, -18.73 ± 1.68 mV, respectively. The morphological characterization of nanoparticles was observed with scanning electron microscopy by stereological method and the physicochemical state of nanoparticles was valued by differential scanning calorimetry. The in vitro drug-release profile of both nanoparticle formulations fitted the Weibull dynamic equation. Pharmacokinetic studies demonstrated that after oral administration of daidzein-loaded phospholipid complexes PLGA nanoparticles and daidzein-loaded cyclodextrin inclusion complexes PLGA nanoparticles to rats at a dose of 10 mg/kg, relative bioavailability was enhanced about 5.57- and 8.85-fold, respectively, compared to daidzein suspension as control. These results describe an effective strategy for oral delivery of daidzein-loaded PLGA nanoparticles and might provide a fresh approach to enhancing the bioavailability of drugs with poor lipophilic and poor hydrophilic properties.Keywords: daidzein, phospholipid complexes, cyclodextrin inclusion complexes, PLGA, nanoparticles

  13. Potentiation of the bioavailability of daidzin by an extract of Radix puerariae.

    Science.gov (United States)

    Keung, W M; Lazo, O; Kunze, L; Vallee, B L

    1996-04-30

    The dose effect of pure daidzin on the suppression of ethanol intake in Syrian golden hamsters was compared with that of crude daidzin contained in a methanol extract of Radix puerariae (RP). EC50 values estimated from the graded dose-response curves for pure daidzin and RP extract daidzin are 23 and 2.3 mg per hamster per day, respectively. Apparently the antidipsotropic activity of the RP extract cannot be accounted for solely by its daidzin content (22 mg/g). In addition to daidzin, six other isoflavones were identified in the RP extract and quantified--namely, puerarin (160 mg per g of extract), genistin (3.7 mg/g), daidzein (2.6 mg/g), daidzein-4',7-diglucoside (1.2 mg/g), genistein (0.2 mg/g), and formononetin (0.16 mg/g). None of these, administered either alone or combined, contributes in any significant way to the antidipsotropic activity of the extract. Plasma daidzin concentration-time curves determined in hamsters administered various doses of pure daidzin or RP extract by i.p.injection indicate that the crude extract daidzin has approximately 10 times greater bioavailability than the pure compound. Reconstruction of the dose-response effects for pure and crude daidzin using bioavailable daidzin rather than administered dose gives a single curve. Synthetic daidzin added to the RP extract acquires the bioavailability of the endogenous daidzin that exists naturally in the extract. These results show that (i) daidzin is the major active principle in methanol extracts of RP, and (ii) additional constituents in the methanol extract of RP assist uptake of daidzin in golden hamsters.

  14. Bioavailability and metabolism of hydroxycinnamates in rats fed with durum wheat aleurone fractions.

    Science.gov (United States)

    Calani, Luca; Ounnas, Fayçal; Salen, Patricia; Demeilliers, Christine; Bresciani, Letizia; Scazzina, Francesca; Brighenti, Furio; Melegari, Camilla; Crozier, Alan; de Lorgeril, Michel; Del Rio, Daniele

    2014-08-01

    The consumption of wholemeal cereals has been associated with the reduced risk of several chronic diseases, and the mechanisms behind these protective effects may be linked, besides dietary fiber and micronutrients, to an increased intake of hydroxycinnamates contained in the bran. Among bran fractions, aleurone usually contains the highest concentration of ferulic acid and diferulic acid esters linked to arabinoxylans representing the most relevant subclasses. The aim of the present study was to evaluate the absorption of hydroxycinnamates by measuring the urinary metabolite profiles of rats fed with the two different aleurone fractions (the inner part of the aleurone, named wheat aleurone A, WA-A, and the outer part, named wheat aleurone B, WA-B). An acute feeding experiment with two rat groups consuming equivalent amounts of total ferulic acid from the different aleurone fractions was carried out to evaluate ferulic acid bioavailability as affected by different sources. A chronic feeding experiment was also conducted with two rat groups consuming the same amount of the two different aleurone fractions, carried out to investigate the short-term metabolism and absorption of aleurone phenolics. The results revealed higher increases in the 24 h-excretion of phenolic metabolites/catabolites in aleurone fed rats compared to rats fed with a regular diet. Specifically, in the chronic feeding, ferulic acid was more bioavailable when WA-A was ingested. Based on previous observations, demonstrating various positive physiological responses to ferulic acid and aleurone fractions characterized by higher phenolic bioavailability, our results indicate that the WA-A fraction has potentially interesting nutritional characteristics that might be used for the formulation of new wheat based products.

  15. Evaluation of bacterial strategies to promote the bioavailability of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, A.R.; Karlson, U. [Dept. of Environmental Chemistry and Microbiology, National Environmental Research Inst., Roskilde (Denmark)

    2004-07-01

    Polycyclic aromatic hydrocarbon (PAHs)-degrading bacteria may enhance the bioavailability of PAHs by excreting biosurfactants, by production of extracellular polymeric substances, or by forming biofilms. We tested these hypotheses in pure cultures of PAHs-degrading bacterial strains. Most of the strains did not substantially reduce the surface tension when grown on PAHs in liquid shaken cultures. Thus, pseudo-solubilization of PAHs in biosurfactant micelles seems not to be a general strategy for these isolates to enhance PAHs-bioavailability. Three semi-colloid Sphingomonas polysaccharides all increased the solubility of PAHs (Gellan 1.3- to 5.4-fold, Welan 1.8- to 6.0-fold and Rhamsan 2.4- to 9.0-fold). The increases were most pronounced for the more hydrophobic PAHs. The polysaccharide-sorbed PAHs were bioavailable. Mineralization rates of 9-[{sup 14}C]-phenanthrene and 3-[{sup 14}C]-fluoranthene by Sphingobium EPA505, were similar with and without sphingans, indicating that mass-transfer rates from PAHs crystals to the bulk liquid were unaffected by the polysaccharides. Biofilm formation on PAHs crystals may favor the diffusive mass transfer of PAHs from crystals to the bacterial cells. A majority of the PAHs-degraders tested formed biofilms in microtiter wells coated with PAHs crystals. For strains capable of growing on different PAHs; the more soluble the PAHs, the lower the percentage of cells attached. Biofilm formation on PAHs-sources was the predominant mechanism among the tested bacteria to overcome mass transfer limitations when growing on poorly soluble PAHs. (orig.)

  16. Comparison of antioxidant activity and bioavailability of tea epicatechins with their epimers.

    Science.gov (United States)

    Xu, Jin Ze; Yeung, Sai Ying Venus; Chang, Qi; Huang, Yu; Chen, Zhen-Yu

    2004-06-01

    Canned and bottled tea drinks contain not only green tea epicatechins (GTE), namely (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epicatechin (EC), but also four GTE epimers, namely (-)-gallocatechin gallate (GCG), (-)-catechin gallate (CG), (-)-gallocatechin (GC) and (-)-catechin (C). In the present study we examined the antioxidant activity and bioavailability of these epimers compared with their corresponding precursors. The epimerisation reaction was induced by autoclaving GTE extract derived from longjing green tea at 120 degrees C for 20 min. Isolation and purification of each GTE and epimer were accomplished by various column chromatographic and semi-preparative HPLC techniques. The antioxidant activity of each epimer with its corresponding GTE precursor was conducted in the three in vitro systems, namely human LDL oxidation, ferric reducing-antioxidant power (FRAP), and anti-2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assays. The results of all three assays demonstrated that CG had similar antioxidant activity with its precursor ECG, while GC was less potent as an antioxidant than its precursor EGC. Regarding EGCG and GCG, the antioxidant potency was similar for both LDL oxidation and DPPH free radical assays, but GCG was statistically less effective than EGCG in the FRAP assay. For EC and C, the latter had less anti-free radical activity in the DPPH assay, but in LDL oxidation and FRAP assays the antioxidant activity was similar. Oral and intravenous dosing of GTE-epimer mixture led to increase in total plasma antioxidant capacity in rats. In general, both epicatechins and epimers had low bioavailability (0.08-0.31) and most of the observed differences between epicatechins and their corresponding epimers were small, even if they were statistically significant in some cases. It was concluded that the epimerisation reaction occurring in manufacturing canned and bottled tea drinks would not

  17. 1H NMR Metabolomics: A New Molecular Level Tool for Assessment of Organic Contaminant Bioavailability to Earthworms in Soil

    Science.gov (United States)

    McKelvie, J. R.; Wolfe, D. M.; Celejewski, M. A.; Simpson, A. J.; Simpson, M. J.

    2009-05-01

    At contaminated field sites, the complete removal of polycyclic aromatic hydrocarbons (PAHs) is rarely achieved since a portion of these compounds remain tightly bound to the soil matrix. The concentration of PAHs in soil typically decreases until a plateau is reached, at which point the remaining contaminant is considered non- bioavailable. Numerous soil extraction techniques, including cyclodextrin extraction, have been developed to estimate contaminant bioavailability. However, these are indirect methods that do not directly measure the response of organisms to chemical exposure in soil. Earthworm metabolomics offers a promising new way to directly evaluate the bioavailability and toxicity of contaminants in soil. Metabolomics involves the measurement of changes in small-molecule metabolites, including sugars and amino acids, in living organisms due to an external stress, such as contaminant exposure. The objective of this study was to compare cyclodextrin extraction of soil (a bioavailability proxy) and 1H NMR metabolomic analysis of aqueous earthworm tissue extracts as indicators of contaminant bioavailability. A 30 day laboratory experiment was conducted using phenanthrene-spiked sphagnum peat soil and the OECD recommended earthworm species for toxicity testing, Eisenia fetida. The initial phenanthrene concentration in the soil was 320 mg/kg. Rapid biodegradation of phenanthrene occurred and concentrations decreased to 16 mg/kg within 15 days. After 15 days, phenanthrene biodegradation slowed and cyclodextrin extraction of the soil suggested that phenanthrene was no longer bioavailable. Multivariate statistical analysis of the 1H NMR spectra for E. fetida tissue extracts indicated that the metabolic profile of phenanthrene exposed earthworms differed from control earthworms throughout the 30 day experiment. This suggests that the residual phenanthrene remaining in the soil after 15 days continued to elicit a metabolic response, even though it was not

  18. Bioaccessibility and bioavailability of methylmercury from seafood commonly consumed in North America: In vitro and epidemiological studies.

    Science.gov (United States)

    Siedlikowski, Maia; Bradley, Mark; Kubow, Stan; Goodrich, Jaclyn M; Franzblau, Alfred; Basu, Niladri

    2016-08-01

    Methylmercury (MeHg) is a global contaminant of concern and human exposures are largely realized via seafood consumption. While it is assumed that 95-100% of the ingested MeHg from seafood reaches systemic circulation, recent in vitro studies have yielded results to suggest otherwise. Of the published studies to have characterized the bioaccessibility or bioavailability of MeHg from seafood, only a handful of seafood species have been characterized, there exists tremendous variability in data within and across species, few species of relevance to North America have been studied, and none of the in vitro studies have adapted results to an epidemiology study. The objective of the current study was two-fold: (a) to characterize in vitro MeHg bioaccessibility and bioavailability from ten commonly consumed types of seafood in North America; and (b) to apply the bioaccessibility and bioavailability data from the in vitro study to an existing human MeHg exposure assessment study. Raw seafood samples (cod, crab, halibut, salmon, scallop, shrimp, tilapia, and three tuna types: canned light, canned white, fresh) were purchased in Montreal and their MeHg concentrations generally overlapped with values reported elsewhere. The bioaccessibility of MeHg from these samples ranged from 50.1±19.2 (canned white tuna) to 100% (shrimp and scallop) of the amount measured in the raw undigested sample. The bioavailability of MeHg from these samples ranged from 29.3±10.4 (crab) to 67.4±9.7% (salmon) of the value measured in the raw undigested sample. There were significant correlations between the initial MeHg concentration in seafood with the percent of that Hg that was bioaccessible (r=-0.476) and bioavailable (r=-0.294). When the in vitro data were applied to an existing MeHg exposure assessment study, the estimated amount of MeHg absorbed into systemic circulation decreased by 25% and 42% when considering bioaccessibility and bioavailability, respectively. When the in vitro data

  19. Drug-delivery systems of green tea catechins for improved stability and bioavailability.

    Science.gov (United States)

    Rodrigues, C F; Ascenção, K; Silva, F A M; Sarmento, B; Oliveira, M B P P; Andrade, J C

    2013-01-01

    Numerous studies in humans, animal models and cell lines have suggested the potential benefits from the consumption of green tea polyphenols, including prevention of cancer and heart diseases. However these potential effects have been strongly limited by green tea catechins low bioavailability, which hinders the development of therapeutic applications. In this review formulations that are being proposed for delivery of green tea catechins are discussed. New delivery systems are presented as valid alternatives to overcome the limitations such as green tea catechins poor stability or intestinal absorption.

  20. Speciation and bioavailability of selenium in yeast-based intervention agents used in cancer chemoprevention studies

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Hansen, Marianne; Paulin, H.

    2004-01-01

    This study investigated the speciation and bioavailability of selenium in yeast-based intervention agents from multiple manufacturers from several time points. Sources of selenized yeast included Nutrition 21 (San Diego, CA), which supplied the Nutritional Prevention of Cancer (NPC) Trial from 1981......-1996; Cypress Systems (Fresno, CA; 1997-1999); and Pharma Nord (Vejle, Denmark; 1999-2000), which supplied the Prevention of Cancer by Intervention by Selenium (PRECISE) Trial pilot studies. The low-molecular-selenium species were liberated from the samples by proteolytic hydrolysis followed by separation...

  1. Microparticles Containing Curcumin Solid Dispersion: Stability, Bioavailability and Anti-Inflammatory Activity

    OpenAIRE

    Teixeira, C. C. C.; Mendonça, L. M.; Bergamaschi, M. M.; QUEIROZ, R. H. C.; Souza, G. E. P.; L. M. G. ANTUNES; Freitas, L. A. P. de

    2015-01-01

    This work aimed at improving the solubility of curcumin by the preparation of spray-dried ternary solid dispersions containing Gelucire®50/13-Aerosil® and quantifying the resulting in vivo oral bioavailability and anti-inflammatory activity. The solid dispersion containing 40% of curcumin was characterised by calorimetry, infrared spectroscopy and X-ray powder diffraction. The solubility and dissolution rate of curcumin in aqueous HCl or phosphate buffer improved up to 3600- and 7.3-fold, res...

  2. Characterization and Bioavailability of Wogonin by Different Administration Routes in Beagles

    Science.gov (United States)

    Zhu, Na; Li, Jian-chun; Zhu, Jin-xiu; Wang, Xiu; Zhang, Jin

    2016-01-01

    Background With the gradually accumulating research on pharmacological activity of wogonin, the in vitro analysis research on wogonin has become more and more popular, but there are very few reports about in vivo detection, and there are no solid dispersions (SDs) of Wogonin. The aim of this study was to explore the formation of solid dispersions (SDs) of wogonin. The reasons for the low bioavailability were studied through different routes of administration. Material/Methods SDs was formulated using the solvent evaporation method via polyvinylpyrrolidone K30 (PVP). The characterization of the drug and its carrier was detected by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The serum concentrations of Wogonin were detected using the LC-MS/MS method. Six beagles were fed 3 different formulations of wogonin in 3 cycles. Results The SDs of wogonin had a higher solubility than the physical mixtures. Based on XRD and DSC, wogonin was transformed from a crystalline morphology to an amorphous structure. The main pharmacokinetic parameters of i.g. administration (crude material and SD) and i.v. route were as follows: Cmax (2.5±1.1), (7.9±3.3), and (6838.7±1322.1) μg/L, tmax (0.7±0.3) and (0.3±0.2) h for the former, AUC0-t (7.1±2.0), (21.0±3.2) and (629.7±111.8) μg·h/L. The absolute bioavailability of native wogonin and wogonin arginine solution were (0.59±0.35)% and (3.65±2.60)%. Further research showed that the low bioavailability of wogonin might be associated with low solubility and rapid combination with glucuronic acid in vivo. Conclusions The significantly increased solubility of SDs and the further preparation of arginine solution could significantly increase the bioavailability of wogonin. PMID:27744456

  3. Preparation, characterization and relative bioavailability of oral elemene o/w microemulsion.

    Science.gov (United States)

    Zeng, Zhaowu; Zhou, Guanglin; Wang, Xiaoli; Huang, Eric Zhijian; Zhan, Xiaori; Liu, Jun; Wang, Shuling; Wang, Anming; Li, Haifeng; Pei, Xiaolin; Xie, Tian

    2010-09-07

    The objective was to develop an elemene oil/water (o/w) microemulsion and evaluate its characteristics and oral relative bioavailability in rats. Elemene was used as the oil phase and drug, polysorbate 80 as a surfactant along with ethanol, propylene glycol, and glycerol as the cosurfactants. The microemulsion was prepared by mixing method, or ultrasonication method in an ultrasonic bath. Its three-dimensional response surface diagram was drawn by Mathcad software. The microemulsion was characterized by visual observation, cross-polarized microscopy, size, zeta potential, acidity, viscosity, and surface tension measurement. The drug content and entrapment efficiency were determined by ultra fast liquid chromatography (UFLC) and liquid surface method. Blood was drawn from rats at different time points after oral administration of an elemene microemulsion or a commercial elemene emulsion for measurement of the drug in plasma by UFLC to establish the pharmacokinetic parameters and relative bioavailability. The elemene microemulsion as a clarified and isotropic system containing 1% elemene (w/v), 5% ethanol (v/v), 15% propylene glycol (v/v), 15% glycerol (v/v), and 5% polysorbate 80 (w/v), was characterized as (57.7 ± 2.8) nm in size, 0.485 ± 0.032 in polydispersity index, (3.2 ± 0.4) mv in zeta potential, (5.19 ± 0.08) in pH, 6 mpa·s in viscosity, (31.8 ± 0.3) mN·m(-1) in surface tension, (8.273 ± 0.018) mg·mL(-1) in content of β-elemene, and (99.81 ± 0.24)% in average entrapment efficiency. The area under the concentration-time curves from 0 h to 24 h (AUC(0→24h)) of the elemene microemulsion and commercial elemene emulsion were integrated to be 3.092 mg·h·L(-1) and 1.896 mg·h·L(-1) respectively, yielding a relative bioavailability of 163.1%. The present study demonstrates the elemene microemulsion as a new formulation with ease of preparation, high entrapment efficiency, excellent clarity, good stability, and improved bioavailability.

  4. Enhanced Lacto-Tri-Peptide Bio-Availability by Co-Ingestion of Macronutrients.

    Directory of Open Access Journals (Sweden)

    Gabriella A M Ten Have

    Full Text Available Some food-derived peptides possess bioactive properties, and may affect health positively. For example, the C-terminal lacto-tri-peptides Ile-Pro-Pro (IPP, Leu-Pro-Pro (LPP and Val-Pro-Pro (VPP (together named here XPP are described to lower blood pressure. The bioactivity depends on their availability at the site of action. Quantitative trans-organ availability/kinetic measurements will provide more insight in C-terminal tri-peptides behavior in the body. We hypothesize that the composition of the meal will modify their systemic availability. We studied trans-organ XPP fluxes in catheterized pigs (25 kg; n=10 to determine systemic and portal availability, as well as renal and hepatic uptake of a water-based single dose of synthetic XPP and a XPP containing protein matrix (casein hydrolyte, CasH. In a second experiment (n=10, we compared the CasH-containing protein matrix with a CasH-containing meal matrix and the modifying effects of macronutrients in a meal on the availability (high carbohydrates, low quality protein, high fat, and fiber. Portal availability of synthetic XPP was 0.08 ± 0.01% of intake and increased when a protein matrix was present (respectively 3.1, 1.8 and 83 times for IPP, LPP and VPP. Difference between individual XPP was probably due to release from longer peptides. CasH prolonged portal bioavailability with 18 min (absorption half-life, synthetic XPP: 15 ± 2 min, CasH: 33 ± 3 min, p<0.0001 and increased systemic elimination with 20 min (synthetic XPP: 12 ± 2 min; CasH: 32 ± 3 min, p<0.0001. Subsequent renal and hepatic uptake is about 75% of the portal release. A meal containing CasH, increased portal 1.8 and systemic bioavailability 1.2 times. Low protein quality and fiber increased XPP systemic bioavailability further (respectively 1.5 and 1.4 times. We conclude that the amount and quality of the protein, and the presence of fiber in a meal, are the main factors that increase the systemic bioavailability of food

  5. Relative bioavailability of sodium cromoglycate to the lung following inhalation, using urinary excretion

    Science.gov (United States)

    Aswania, O A; Corlett, S A; Chrystyn, H

    1999-01-01

    Aims To determine if a urinary excretion method, previously described for salbutamol, could also indicate the relative bioavailability of sodium cromoglycate to the lung following inhalation from a metered dose inhaler. Method Inhaled (INH), inhaled+oral charcoal (INHC), oral (ORAL) and oral+oral charcoal (ORALC) 20 mg doses of sodium cromoglycate were given via a randomised cross-over design to 11 healthy volunteers trained on how to use a metered dose inhaler. Urine samples were collected at 0.0, 0.5, 1.0 and up to 24 h post dosing and the sodium cromoglycate urinary concentration was measured using a high performance liquid chromatographic method. Results No sodium cromoglycate was detected in the urine up to 24 h following ORALC dosing. A mean (s.d.) of 3.6 (4.3) μg, 10.4 (10.9) μg and 83.7 (71.1) μg of the ORAL dose was excreted, in the urine, during the 0.5, 1.0 and 24 h post dose collection periods, respectively. Following INH dosing, the renal excretion was significantly higher (P < 0.01) with 32.9 (14.5) μg, 61.2 (28.3) μg and 305.6 (82.3) μg excreted, respectively. The SCG excreted at 0.5, 1.0 and 24 h collection periods following INHC dosing were 26.3 (8.4) μg, 49.3 (18.1) μg and 184.9 (98.4) μg, respectively. There was no significant difference between the excretion rate of sodium cromoglycate following INHC when compared with INH dosing in the first 0.5 and 1.0 h. Conclusions The urinary excretion of sodium cromoglycate in the first 0.5 h post inhalation can be used to compare the relative lung deposition of two inhaled products or of the same product using different inhalation techniques. This represents the relative bioavailability of sodium cromoglycate to the lung following inhalation. Similar 24 h urinary excretion of sodium cromoglycate can be use to compare the total dose delivered to the body from two different inhalation products/inhalation methods. This represents the relative bioavailability of sodium cromoglycate to the body

  6. Effect of organic amendments and mineral fertilizer on zinc bioavailability, plant content and translocation

    Science.gov (United States)

    Chami, Ziad Al; Cavoski, Ivana; Mondelli, Donato; Miano, Teodoro

    2013-04-01

    Organic matter plays a key role in heavy metal bioavailability through changes in soil chemical characteristics, and by its metal-chelating ability, the latter being one of the most important factors controlling the mobility and bioavailability of heavy metals in the soil-plant system. In this research, rocket (Eruca vesicaria L. Cavalieri), a common edible plant species in the Mediterranean regions, was used as bio-indicator to evaluate the effect of different organic amendments on Zn toxicity, absorption, and translocation. The main objectives of this study were to investigate the bioavailability of Zn in an artificially contaminated soil after the addition of compost, manure and chemical fertilizers at agronomically recommended doses and to evaluate their ability to reduce Zn concentration in the edible plant part. A greenhouse pots experiment was carried out using rocket plant grown on an artificially contaminated soil. In this study, the effect of compost, manure and chemical fertilizers on Zn fate in a soil-plant system was evaluated. At the end of the experiment main growth parameters and Zn content in plants were determined. In addition, Zn speciation in the soil was assessed using the original BCR sequential extraction and the DTPA extraction. The overall assessment of experimental results is that compost, followed by chemical fertilizers treatments, was the most efficient in enhancing plant growth and decreasing metal toxicity and concentrations in plant tissues. Manure amendments increased plant Zn content and toxicity in rocket plants. In the case of compost treatment, this effect can be attributed to the humified OM present in compost; while the negative effect of manure is due to its content in low molecular weight organic acids. The effect of chemical fertilizers treatment could be attributed to the addition of P fertilizer in soluble and highly available forms to the plants. On the contrary, using DTPA and BCR sequential extraction procedure, all

  7. Is it possible to increase bioavailability but not environmental risk of PAHs in bioremediation?

    Science.gov (United States)

    Ortega-Calvo, J J; Tejeda-Agredano, M C; Jimenez-Sanchez, C; Congiu, E; Sungthong, R; Niqui-Arroyo, J L; Cantos, M

    2013-10-15

    The current poor predictability of end points associated with the bioremediation of polycyclic aromatic hydrocarbons (PAHs) is a large limitation when evaluating its viability for treating contaminated soils and sediments. However, we have seen a wide range of innovations in recent years, such as an the improved use of surfactants, the chemotactic mobilization of bacterial inoculants, the selective biostimulation at pollutant interfaces, rhizoremediation and electrobioremediation, which increase the bioavailability of PAHs but do not necessarily increase the risk to the environment. The integration of these strategies into practical remediation protocols would be beneficial to the bioremediation industry, as well as improve the quality of the environment.

  8. Assessment of polymorphic metabolite data in bioavailability/bioequivalence studies - considerations and challenges

    Directory of Open Access Journals (Sweden)

    Nuggehally R Srinivas

    2011-01-01

    Full Text Available Bioavailability (BA/ bioequivalence (BE studies are the cornerstone for the approval of generic drugs. While BA/BE assessment involving the pharmacokinetic data of the parent compound has been routinely performed, the introduction of the assessment of metabolite(s data, alone or in addition to parent compound, has also emerged. In this context, the assessment of BA/BE of metabolite(s may pose additional complexities and challenges, if the metabolic pathway is under the influence of a polymorphic enzyme. This communication provides brief perspectives on the challenges and study design considerations for the assessment of polymorphic metabolite in BA/BE studies.

  9. Bioavailability of zinc and phosphorus in calcareous soils as affected by citrate exudation

    OpenAIRE

    Duffner, A.; Hoffland, E.; Temminghoff, E. J. M.

    2012-01-01

    Aims Zinc (Zn) and phosphorus (P) deficiency often occurs at the same time and limits crop production in many soils. It has been suggested that citrate root exudation is a response of plants to both deficiencies. We used white lupin (Lupinus albus L.) as a model plant to clarify if citrate exuded by roots could increase the bioavailability of Zn and P in calcareous soils. Methods White lupin was grown in nutrient solution and in two calcareous soils in a rhizobox. Rhizosphere soil solution wa...

  10. Improving Oral Bioavailability of Sorafenib by Optimizing the "Spring" and "Parachute" Based on Molecular Interaction Mechanisms.

    Science.gov (United States)

    Liu, Chengyu; Chen, Zhen; Chen, Yuejie; Lu, Jia; Li, Yuan; Wang, Shujing; Wu, Guoliang; Qian, Feng

    2016-02-01

    Sorafenib is a clinically important oral tyrosine kinase inhibitor for the treatment of various cancers. However, the oral bioavailability of sorafenib tablet (Nexavar) is merely 38-49% relative to the oral solution, due to the low aqueous solubility of sorafenib and its relatively high daily dose. It is desirable to improve the oral bioavailability of sorafenib to expand the therapeutic window, reduce the drug resistance, and enhance patient compliance. In this study, we observed that the solubility of sorafenib could be increased ∼50-fold in the coexistence of poly(vinylpyrrolidone-vinyl acetate) (PVP-VA) and sodium lauryl sulfate (SLS), due to the formation of PVP-VA/SLS complexes at a lower critical aggregation concentration. The enhanced solubility provided a faster initial sorafenib dissolution rate, analogous to a forceful "spring" to release drug into solution, from tablets containing both PVP-VA and SLS. However, SLS appears to impair the ability of PVP-VA to act as an efficient "parachute" to keep the drug in solution and maintain drug supersaturation. Using 2D (1)H NMR, (13)C NMR, and FT-IR analysis, we concluded that the solubility enhancement and supersaturation of sorafenib were achieved by PVP-VA/SLS complexes and PVP-VA/sorafenib interaction, respectively, both through molecular interactions hinged on the PVP-VA VA groups. Therefore, a balance between "spring" and "parachute" must be carefully considered in formulation design. To confirm the in vivo relevance of these molecular interaction mechanisms, we prepared three tablet formulations containing PVP-VA alone, SLS alone, and PVP-VA/SLS in combination. The USP II in vitro dissolution and dog pharmacokinetic in vivo evaluation showed clear differentiation between these three formulations, and also good in vitro-in vivo correlation. The formulation containing PVP-VA alone demonstrated the best bioavailability with 1.85-fold and 1.79-fold increases in Cmax and AUC, respectively, compared with the

  11. Optimization of caseinate-coated simvastatin-zein nanoparticles: improved bioavailability and modified release characteristics

    Directory of Open Access Journals (Sweden)

    Ahmed OA

    2015-01-01

    Full Text Available Osama AA Ahmed,1,2 Khaled M Hosny,1,3 Majid M Al-Sawahli,1,4 Usama A Fahmy11Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia; 2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Minia University, Minia, Egypt; 3Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Beni Suef University, Beni Suef, Egypt; 4Holding Company for Biological Products & Vaccines (VACSERA, Cairo, EgyptAbstract: The current study focuses on utilization of the natural biocompatible polymer zein to formulate simvastatin (SMV nanoparticles coated with caseinate, to improve solubility and hence bioavailability, and in addition, to modify SMV-release characteristics. This formulation can be utilized for oral or possible depot parenteral applications. Fifteen formulations were prepared by liquid–liquid phase separation method, according to the Box–Behnken design, to optimize formulation variables. Sodium caseinate was used as an electrosteric stabilizer. The factors studied were: percentage of SMV in the SMV-zein mixture (X1, ethanol concentration (X2, and caseinate concentration (X3. The selected dependent variables were mean particle size (Y1, SMV encapsulation efficiency (Y2, and cumulative percentage of drug permeated after 1 hour (Y3. The diffusion of SMV from the prepared nanoparticles specified by the design was carried out using an automated Franz diffusion cell apparatus. The optimized SMV-zein formula was investigated for in vivo pharmacokinetic parameters compared with an oral SMV suspension. The optimized nanosized SMV-zein formula showed a 131 nm mean particle size and 89% encapsulation efficiency. In vitro permeation studies displayed delayed permeation characteristics, with about 42% and 85% of SMV cumulative amount released after 12 and 48 hours, respectively. Bioavailability estimation in rats revealed an augmentation in SMV bioavailability

  12. Time and moisture effects on total and bioavailable copper in soil water extracts

    DEFF Research Database (Denmark)

    Tom-Petersen, Andreas; Hansen, H.C.B.; Nybroe, O.

    2004-01-01

    between total metal content and metal toxicity calls for integrated chemical and biological analysis. The aim of this work was to determine time- and moisture-dependent changes in total water-extractable Cu as well as bioavailable Cu in soil water extracts. Measurements of total water-extractable copper...... to increase with time. The moisture content of the soil was important for Cu retention. Dry soil had higher [Cu](tot) concentrations than humid soil, but the [Cu](bio) to [Cu](tot) ratio was lower in the dry soil. Alternating drying and wetting did not lead to a more rapid Cu retention than observed under...

  13. A liner mode of reversible metabolism and its application to bioavailability assessment.

    Science.gov (United States)

    Hwang, S; Kwan, K C; Albert, K S

    1981-12-01

    A theoretical basis has been established for the bioavailability assessment of drug and metabolite wherein the biotransformation of one to the other is reversible. The method is applicable to linear systems and requires knowledge of drug metabolite clearance rates as well as the rate of their interconversion. While not necessary, an unconventional definition of plasma clearance appears desirable and expeditious. Depending on the experimental situation, clearance values may change between treatments; these changes should be recognized and accommodated. Alterations in experimental design are discussed as means to minimize the need for assumptions and/or to provide data in suitable form as tests of internal consistency.

  14. Relative bioavailability of oral low dose methotrexate. A comparison of 2 different formulations.

    Science.gov (United States)

    Fosså, S D; Tveit, K; Börmer, O; Moxnes, A; Jørgensen, N P; Orjaseter, H; Kristoffersen, D T

    1988-01-01

    In 39 patients the bioavailability of methotrexate from the two tablets Emthexat 2.5 mg and Methotrexate 2.5 mg was assessed in a double-blind study after a single oral dose of 30 mg/m2 Methotrexate. There was a considerable inter-individual variation of the serum pharmacokinetics in regard to Cmax and tmax, independent on the MTX formulation. Emthexat 2.5 mg tablets and Methotrexate 2.5 mg tablets were bioequivalent according to the definition (AUCE greater than or equal to AUCM X 80%).

  15. Influence of dissolved organic matter on nickel bioavailability and toxicity to Hyalella azteca in water-only exposures.

    Science.gov (United States)

    Doig, Lorne E; Liber, Karsten

    2006-03-10

    Dissolved organic matter (DOM) is known to reduce the bioavailability of metals in aquatic systems. This study evaluated the effects of DOM from various sources (e.g., Little Bear Lake sediment, Suwannee River, peat moss) and various DOM fractions (humic acids, HA; fulvic acids, FA) on the bioavailability of nickel (Ni) to Hyalella azteca, a common freshwater benthic invertebrate. In particular, this study was conducted to evaluate the effect of surficial sediment DOM on Ni bioavailability. Short-term (48 h) acute toxicity tests with H. azteca conducted in synthetic water demonstrated that the aqueous Ni concentrations required for lethality were greater than what could be significantly complexed by environmentally relevant concentrations of dissolved organic carbon (DOC: 0.6-30.4 mg/L). At Ni concentrations sublethal to H. azteca (500 microg/L), the bioavailability of Ni was significantly reduced in the presence of representative surface water DOC concentrations regardless of DOC source or fraction. DOC fraction (i.e., FA and HA) differentially affected Ni speciation, but had little or no effect on Ni accumulation by H. azteca. Tissue Ni was found to be strongly dependent upon the Ni(2+) concentration in the exposure solutions and the Ni:DOC ratio. Overall, the concentration of DOC played a greater role than either DOC source or fraction in determining Ni speciation and hence bioavailability and toxicity to H. azteca.

  16. Improving oral bioavailability of metformin hydrochloride using water-in-oil microemulsions and analysis of phase behavior after dilution.

    Science.gov (United States)

    Li, Yuan; Song, Jiaqi; Tian, Ning; Cai, Jie; Huang, Meihong; Xing, Qiao; Wang, Yalong; Wu, Chuanbin; Hu, Haiyan

    2014-10-01

    Microemulsions show significant promise for enhancing the oral bioavailability of biopharmaceutics classification system (BCS) class II drugs, but how about class III drugs remains unclear. Here we employed metformin hydrochloride (MET) as the model drug and prepared drug-loaded water-in-oil (W/O) microemulsions selecting different hydrophile-lipophile balance (HLB) surfactant systems, using HLB 8 as a cut-off. We examined the phase behaviors of microemulsions after dilution and attempted to correlate these behaviors to drug oral bioavailability. ME-A, including a lower content of surfactants (35%), underwent a transition of W/O emulsion and then became a stable O/W emulsion in a light milky appearance; ME-B, in contrast, introducing a higher content of surfactants (45%), still remained transparent or semitransparent upon dilution. Unexpectedly, ME-A showed significantly higher oral bioavailability, which can be reduced by blocking the lymphatic absorption pathway. Comparatively, the AUC of ME-B is lower, close to MET solution. Both microemulsions behaved similarly in intestinal perfusion test because of the dilution before perfusion, lacking of the important phase transition of W/O emulsion. These findings suggest that W/O microemulsions improve oral bioavailability of BCS class III drug by promoting lymphatic absorption. Analyzing the phase behavior of microemulsions after dilution may help predict the drug oral bioavailability and optimize formulations.

  17. PAH fate during the anaerobic digestion of contaminated sludge: Do bioavailability and/or cometabolism limit their biodegradation?

    Science.gov (United States)

    Barret, M; Carrère, H; Delgadillo, L; Patureau, D

    2010-07-01

    The anaerobic removal of 13 Polycyclic Aromatic Hydrocarbons (PAHs) was measured in five continuous anaerobic digestors with different feed sludge, in which abiotic losses were neglected. These feeds were chosen to generate different levels of PAH bioavailability and cometabolism within the reactors. Based on the accurate modelling of PAH sorption in sludge, the aqueous fraction (including free and sorbed-to-dissolved-and-colloidal-matter PAHs) was demonstrated to be bioavailable, which validated a widespread assumption about micropollutants bioavailability in sludge. It was also demonstrated that bioavailability is not the only influencing factor. Indeed, PAHs biodegradation resulted from a combination of bioavailability and cometabolism. An equation adapted from Criddle (1993, The Kinetics of Cometabolism. Biotechnology and Bioengineering 41, 1048-1056) that takes into account both mechanisms was shown to fit the experimental data, with dry matter removal rate identified as the criteria for cometabolism. The existence of a threshold of dry matter cometabolism was suggested, below which PAHs removal would not be possible. The parameters of the Criddle equation were demonstrated to depend on PAH molecular structure, and the results suggest that they would also be influenced by substrate composition and microbial population. This research provided original outcomes for the assessment of micropollutants fate. Indeed, the understanding of the driving mechanisms was improved, which has implications for the optimization of micropollutants removal.

  18. Bioavailability and bioaccumulation of metal-based engineered nanomaterials in aquatic environments: concepts and processes: chapter 5

    Science.gov (United States)

    Luoma, Samuel N.; Khan, Farhan R.; Croteau, Marie-Noële

    2014-01-01

    Bioavailability of Me-ENMs to aquatic organisms links their release into the environment to ecological implications. Close examination shows some important differences in the conceptual models that define bioavailability for metals and Me-ENMs. Metals are delivered to aquatic animals from Me-ENMs via water, ingestion, and incidental surface exposure. Both metal released from the Me-ENM and uptake of the nanoparticle itself contribute to bioaccumulation. Some mechanisms of toxicity and some of the metrics describing exposure may differ from metals alone. Bioavailability is driven by complex interaction of particle attributes, environmental transformations, and biological traits. Characterization of Me-ENMs is an essential part of understanding bioavailability and requires novel methodologies. The relative importance of the array of processes that could affect Me-ENM bioavailability remains poorly known, but new approaches and models are developing rapidly. Enough is known, however, to conclude that traditional approaches to exposure assessment for metals would not be adequate to assess risks from Me-ENMs.

  19. Improving the relationship between soil characteristics and metal bioavailability by using reactive fractions of soil parameters in calcareous soils.

    Science.gov (United States)

    de Santiago-Martín, Ana; van Oort, Folkert; González, Concepción; Quintana, José R; Lafuente, Antonio L; Lamy, Isabelle

    2015-01-01

    The contribution of the nature instead of the total content of soil parameters relevant to metal bioavailability in lettuce was tested using a series of low-polluted Mediterranean agricultural calcareous soils offering natural gradients in the content and composition of carbonate, organic, and oxide fractions. Two datasets were compared by canonical ordination based on redundancy analysis: total concentrations (TC dataset) of main soil parameters (constituents, phases, or elements) involved in metal retention and bioavailability; and chemically defined reactive fractions of these parameters (RF dataset). The metal bioavailability patterns were satisfactorily explained only when the RF dataset was used, and the results showed that the proportion of crystalline Fe oxides, dissolved organic C, diethylene-triamine-pentaacetic acid (DTPA)-extractable Cu and Zn, and a labile organic pool accounted for 76% of the variance. In addition, 2 multipollution scenarios by metal spiking were tested that showed better relationships with the RF dataset than with the TC dataset (up to 17% more) and new reactive fractions involved. For Mediterranean calcareous soils, the use of reactive pools of soil parameters rather than their total contents improved the relationships between soil constituents and metal bioavailability. Such pool determinations should be systematically included in studies dealing with bioavailability or risk assessment.

  20. Molecular mechanisms underlying synergistic adhesion of sickle red blood cells by hypoxia and low nitric oxide bioavailability.

    Science.gov (United States)

    Gutsaeva, Diana R; Montero-Huerta, Pedro; Parkerson, James B; Yerigenahally, Shobha D; Ikuta, Tohru; Head, C Alvin

    2014-03-20

    The molecular mechanisms by which nitric oxide (NO) bioavailability modulates the clinical expression of sickle cell disease (SCD) remain elusive. We investigated the effect of hypoxia and NO bioavailability on sickle red blood cell (sRBC) adhesion using mice deficient for endothelial NO synthase (eNOS) because their NO metabolite levels are similar to those of SCD mice but without hypoxemia. Whereas sRBC adhesion to endothelial cells in eNOS-deficient mice was synergistically upregulated at the onset of hypoxia, leukocyte adhesion was unaffected. Restoring NO metabolite levels to physiological levels markedly reduced sRBC adhesion to levels seen under normoxia. These results indicate that sRBC adherence to endothelial cells increases in response to hypoxia prior to leukocyte adherence, and that low NO bioavailability synergistically upregulates sRBC adhesion under hypoxia. Although multiple adhesion molecules mediate sRBC adhesion, we found a central role for P-selectin in sRBC adhesion. Hypoxia and low NO bioavailability upregulated P-selectin expression in endothelial cells in an additive manner through p38 kinase pathways. These results demonstrate novel cellular and signaling mechanisms that regulate sRBC adhesion under hypoxia and low NO bioavailability. Importantly, these findings point us toward new molecular targets to inhibit cell adhesion in SCD.