WorldWideScience

Sample records for bioavailability

  1. Bioavailability

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, J. [National Environmental Research Inst., Silkeborg (Denmark). Dept. of Terrestrial Ecology

    2003-07-01

    Although commonly discussed and debated the scientific basis for adequately using bioavailability in ecological risk assessment is still relatively weak. One of the first obstacles to solve is to define the term properly. It must be recognised that bioavailability is dynamic processes comprising several distinct phases. One is the adsorption/desorption process (chemical availability) controlled by parameters like pH, clay, CEC and organic matter. Another one is a physiological driven uptake process (biological availability) controlled by species-specific parameters like anatomy, feeding strategy, preferences in micro-habitat etc. The last one is an internal allocation process (toxicological availability) controlled by species specific parameters like metabolism, detoxification, storage, excretion, energy resources etc. The complexity of bioavailability means that there seems no straight way forward how to handle bioavailability in the risk assessment procedure. Nevertheless, what almost all people - from scientists to problem holders and responsible authorities - agree upon is that there is a need for alternatives to the common use of the 'total concentration approach'. From an ecological perspective, biological tools would be preferred when assessing risk to ecosystems. However, due to the lower cost and higher reproducibility chemical tools may often be the best suitable solutions. The outcome of mild extraction procedures like CaCl{sub 2} have for example been shown to correlated relatively well to ecotoxicological effects of heavy metals. Bioavailability of organic pollutants has less frequently been correlated to ecological effects of organisms within the soil compartment and adjacent water systems. It has nevertheless been documented that mild extractors like n-butanol, propanol, ethyl acetate and acetonitrile are useful in predicting the uptake of PAHs in earthworms and plants as well as microbial toxicity. (orig.)

  2. Folate bioavailability

    OpenAIRE

    Öhrvik, Veronica

    2009-01-01

    An inadequate folate status is associated with increased risk of anaemia and neural tube defects. In many countries a folate intake below recommendations has been reported for women in childbearing age. However, data on folate intake and status are not always associated, since factors other than intake, e.g. bioavailability, affect folate status. This thesis studied the bioavailability of folate using in vivo and in vitro models. The effect of two pieces of Swedish nutritional advice on folat...

  3. 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

  4. Improved bioavailability

    Directory of Open Access Journals (Sweden)

    Nadia M. Morsi

    2016-09-01

    Full Text Available Timolol maleate (TiM, a nonselective β-adrenergic blocker, is a potent highly effective agent for management of hypertension. The drug suffers from extensive first pass effect, resulting in a reduction of oral bioavailability (F% to 50% and a short elimination half-life of 4 h; parameters necessitating its frequent administration. The current study was therefore, designed to formulate and optimize the transfersomal TiM gel for transdermal delivery. TiM loaded transfersomal gel was optimized using two 23 full factorial designs; where the effects of egg phosphatidyl choline (PC: surfactant (SAA molar ratio, solvent volumetric ratio, and the drug amount were evaluated. The formulation variables; including particle size, drug entrapment efficiency (%EE, and release rate were characterized. The optimized transfersomal gel was prepared with 4.65:1 PC:SAA molar ratio, 3:1 solvent volumetric ratio, and 13 mg drug amount with particle size of 2.722 μm, %EE of 39.96%, and a release rate of 134.49 μg/cm2/h. The permeation rate of the optimized formulation through the rat skin was excellent (151.53 μg/cm2/h and showed four times increase in relative bioavailability with prolonged plasma profile up to 72 h compared with oral aqueous solution. In conclusion, a potential transfersomal transdermal system was successfully developed and the factorial design was found to be a smart tool, when optimized.

  5. Improved Chromatographic Bioavailability Estimations

    National Research Council Canada - National Science Library

    Dorsey, John

    1996-01-01

    .... Since the inception of reversed phase liquid chromatography there have been many attempts to correlate chromatographic retention with bioavailability and the most often used bulk measure, the octanol...

  6. Flavonoid Bioavailability and Attempts for Bioavailability Enhancement

    Science.gov (United States)

    Thilakarathna, Surangi H.; Rupasinghe, H. P. Vasantha

    2013-01-01

    Flavonoids are a group of phytochemicals that have shown numerous health effects and have therefore been studied extensively. Of the six common food flavonoid classes, flavonols are distributed ubiquitously among different plant foods whereas appreciable amounts of isoflavones are found in leguminous plant-based foods. Flavonoids have shown promising health promoting effects in human cell culture, experimental animal and human clinical studies. They have shown antioxidant, hypocholesterolemic, anti-inflammatory effects as well as ability to modulate cell signaling and gene expression related disease development. Low bioavailability of flavonoids has been a concern as it can limit or even hinder their health effects. Therefore, attempts to improve their bioavailability in order to improve the efficacy of flavonoids are being studied. Further investigations on bioavailability are warranted as it is a determining factor for flavonoid biological activity. PMID:23989753

  7. Bioavailability of intranasal metoclopramide.

    OpenAIRE

    Ward, M J; Buss, D C; Ellershaw, J; Nash, A; Routledge, P A

    1989-01-01

    After intranasal administration of metoclopramide, (5 mg in 0.5 ml sterile water) the maximum plasma concentration of 13.5 +/- 7.3 (mean +/- s.d.) ng ml-1 was achieved. Absolute bioavailability was 50.5 +/- 29.5%, 110 +/- 41 min later. We conclude that the intranasal route does not allow rapid absorption of the drug and is not associated with greater bioavailability than the oral route.

  8. Zinc bioavailability in the chick

    International Nuclear Information System (INIS)

    Hempe, J.M.

    1987-01-01

    Methods for assessing zinc bioavailability were evaluated in the chick. A low-zinc chick diet was developed using rehydrated, spray-dried egg white autoclaved at 121 C for 30 min as the primary protein source. The relative bioavailability of zinc from soy flour and beef was determined by whole-body retention of extrinsic 65 Zn, and in slope ratio assays for growth rate and tissue zinc. Compared to zinc carbonate added to an egg white-based diet, all methods gave similar estimates of approximately 100% zinc bioavailability for beef but estimates for soy flour varied widely. The slope ratio assay for growth rate gave the best estimate of zinc bioavailability for soy flour. True absorption, as measured by percent isotope retention from extrinsically labeled soy flour, was 47%

  9. 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.

  10. 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.

  11. Aluminum bioavailability from tea infusion.

    Science.gov (United States)

    Yokel, Robert A; Florence, Rebecca L

    2008-12-01

    The objective was to estimate oral Al bioavailability from tea infusion in the rat, using the tracer (26)Al. (26)Al citrate was injected into tea leaves. An infusion was prepared from the dried leaves and given intra-gastrically to rats which received concurrent intravenous (27)Al infusion. Oral Al bioavailability (F) was calculated from the area under the (26)Al, compared to (27)Al, serum concentration x time curves. Bioavailability from tea averaged 0.37%; not significantly different from water (F=0.3%), or basic sodium aluminum phosphate (SALP) in cheese (F=0.1-0.3%), but greater than acidic SALP in a biscuit (F=0.1%). Time to maximum serum (26)Al concentration was 1.25, 1.5, 8 and 4.8h, respectively. These results of oral Al bioavailability x daily consumption by the human suggest tea can provide a significant amount of the Al that reaches systemic circulation. This can allow distribution to its target organs of toxicity, the central nervous, skeletal and hematopoietic systems. Further testing of the hypothesis that Al contributes to Alzheimer's disease may be more warranted with studies focusing on total average daily food intake, including tea and other foods containing appreciable Al, than drinking water.

  12. Nanoparticulation improves bioavailability of Erlotinib.

    Science.gov (United States)

    Yang, Kyung Mi; Shin, In Chul; Park, Joo Won; Kim, Kab-Sig; Kim, Dae Kyong; Park, Kyungmoon; Kim, Kunhong

    2017-09-01

    Nanoparticulation using fat and supercritical fluid (NUFS TM ) is a drug delivery platform technology enabling efficient and effective formulation of poorly soluble drugs. We performed experiments to examine whether NUFS™ could improve poor bioavailability and reduce fed-fasted bioavailability variances of erlotinib (Ert). NUFS-Ert was prepared using NUFS™ technology; its physical properties were characterized, and drug release was measured. Furthermore, in vitro and in vivo efficacy tests and pharmacokinetic analysis were performed. NUFS-Ert nanoparticles had an average size of 250 nm and were stable for 2 months at 40 °C, 4 °C, and room temperature. The dissolution rate of NUFS-Ert increased in bio-relevant dissolution media. NUFS-Ert was more potent in inhibiting EGF signaling and in suppressing the proliferation of A549, a human non-small cell lung cancer cell line. Furthermore, A549 xenografts in BALB/c nude mice treated with NUFS-Ert regressed more efficiently than those in the mice treated with vehicle or Tarceva ® . In addition, experimental lung metastasis was more efficiently inhibited by NUFS-Ert than by Tarceva ® . The relative bioavailability of NUFS-Ert compared with that of Tarceva ® was 550% and the ratio of the area under the concentration-time curve (AUC) of fed state to the AUC of fasted state was 1.8 for NUFS-Ert and 5.8 for Tarceva ® . NUFS-Ert could improve poor bioavailability and reduce fed-fasted bioavailability variances of Ert. NUFS-Ert was more efficacious than Tarceva ® .

  13. Relative Bioavailability and Bioaccessability and Speciation of ...

    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 assessments and remediation goals, convenient, rapid, reliable, and inexpensive tools are needed to determine soil As bioavailability. Objectives: We evaluated inexpensive methods for assessing As bioavailability in soil as a means to improve human exposure estimates and potentially reduce remediation costs. Methods: Nine soils from residential sites affected by mining or smelting activity and two National Institute of Standards and Technology standard reference materials were evaluated for As bioavailability, bioaccessibility, and speciation. Arsenic bioavailability was determined using an in vivo mouse model, and As bioaccessibility was determined using the Solubility/Bioavailability Research Consortium in vitro assay. Arsenic speciation in soil and selected soil physicochemical properties were also evaluated to determine whether these parameters could be used as predictors of As bio¬availability and bioaccessibility. Results: In the mouse assay, we compared bioavailabilities of As in soils with that for sodium arsenate. Relative bioavailabilities (RBAs) of soil As ranged from 11% to 53% (mean, 33%). In vitro soil As bioaccessibility values were strongly correlated with soil As RBAs (R

  14. Antimony bioavailability in mine soils

    International Nuclear Information System (INIS)

    Flynn, Helen C.; Meharg, Andy A.; Bowyer, Phillipa K.; Paton, Graeme I.

    2003-01-01

    Antimony has low bioavailability in mining and smelting contaminated soils and bacterial biosensors are not suitable for its detection. - Five British former mining and smelting sites were investigated and found to have levels of total Sb of up to 700 mg kg -1 , indicating high levels of contamination which could be potentially harmful. However, this level of Sb was found to be biologically unavailable over a wide range of pH values, indicating that Sb is relatively unreactive and immobile in the surface layers of the soil, remaining where it is deposited rather than leaching into lower horizons and contaminating ground water. Sb, sparingly soluble in water, was unavailable to the bacterial biosensors tested. The bioluminescence responses were correlated to levels of co-contaminants such as arsenic and copper, rather than to Sb concentrations. This suggests that soil contamination by Sb due to mining and smelting operations is not a severe risk to the environment or human health provided that it is present as immobile species and contaminated sites are not used for purposes which increase the threat of exposure to identified receptors. Co-contaminants such as arsenic and copper are more bioavailable and may therefore be seen as a more significant risk

  15. Bioavailability and biodistribution of nanodelivered lutein

    Science.gov (United States)

    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 ...

  16. Pharmaceutical and pharmacological approaches for bioavailability

    Indian Academy of Sciences (India)

    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 ...

  17. 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

    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

  18. Bioavailability as a tool in site management

    NARCIS (Netherlands)

    Harmsen, J.; Naidu, R.

    2013-01-01

    Bioavailability can form the basis for describing potential risks that contaminants pose to the environment and human health, and for determining remedial options to reduce risks of contaminant dispersal and toxicity. In assessments of polluted sites, methods to measure bioavailability can lead to a

  19. 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*).

  20. [Bioavailability and factors influencing its rate].

    Science.gov (United States)

    Vraníková, Barbora; Gajdziok, Jan

    Bioavailability can be defined as the rate and range of active ingredient absorption, when it becomes available in the systemic circulation or at the desired site of drug action, respectively. Drug bioavailability after oral administration is affected by anumber of different factors, including physicochemical properties of the drug, physiological aspects, the type of dosage form, food intake, biorhythms, and intra- and interindividual variability of the human population. This article is the first from the series dealing with the bioavailability and methods leading to its improvement. The aim of the present paper is to provide an overview of aspects influencing the rate of bioavailability after oral administration of the active ingredient. Subsequentarticles will provide detailed descriptions of methods used for dug bioavailability improvement, which are here only summarized.

  1. 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 samples...

  2. Dietary factors that affect carotenoid bioavailability

    NARCIS (Netherlands)

    Hof, van het K.H.

    1999-01-01

    Carotenoids are thought to contribute to the beneficial effects of increased vegetable consumption. To better understand the potential benefits of carotenoids, we investigated the bioavailability of carotenoids from vegetables and dietary factors which might influence carotenoid

  3. Enhancement of Solubility and Bioavailability of Candesartan ...

    African Journals Online (AJOL)

    Purpose: To enhance the otherwise poor solubility and bioavailability of candesartan cilexetil (CDS). Methods: This ... PEG 6000-based solid dispersions showed 1st order drug release kinetics. ..... the liver due to quercetin's inhibitory effect on.

  4. 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....

  5. Bioavailability in the boris assessment model

    International Nuclear Information System (INIS)

    Norden, M.; Avila, R.; Gonze, M.A.; Tamponnet, C.

    2004-01-01

    The fifth framework EU project BORIS (Bioavailability Of Radionuclides In Soils: role of biological components and resulting improvement of prediction models) has three scientific objectives. The first is to improve understanding of the mechanisms governing the transfer of radionuclides to plants. The second is to improve existing predictive models of radionuclide interaction with soils by incorporating the knowledge acquired from the experimental results. The last and third objective is to extract from the experimental results some scientific basis for the development of bioremediation methods of radionuclides contaminated soils and to apprehend the role of additional non-radioactive pollutants on radionuclide bio-availability. This paper is focused on the second objective. The purpose of the BORIS assessment model is to describe the behaviour of radionuclides in the soil-plant system with the aim of making predictions of the time dynamics of the bioavailability of radionuclides in soil and the radionuclides concentrations in plants. To be useful the assessment model should be rather simple and use only a few parameters, which are commonly available or possible to measure for different sites. The model shall take into account, as much as possible, the results of the experimental studies and the mechanistic models developed in the BORIS project. One possible approach is to introduce in the assessment model a quantitative relationship between bioavailability of the radionuclides in soil and the soil properties. To do this an operational definition of bioavailability is needed. Here operational means experimentally measurable, directly or indirectly, and that the bioavailability can be translated into a mathematical expression. This paper describes the reasoning behind the chosen definition of bioavailability for the assessment model, how to derive operational expressions for the bioavailability and how to use them in the assessment model. (author)

  6. Bioavailability in ecological risk. Assessment for radionuclides

    International Nuclear Information System (INIS)

    Garnier-Laplace, J.; Gilbin, R.; Della-Vedova, C.; Adam, C.; Simon, O.; Denison, F.; Beaugelin, K.

    2005-01-01

    The guidance for performing Ecological Risk Assessments (ERA) in Europe has been published in 2003 in the EC's Technical Guidance Document. This document constitutes the official reference in which current water quality standards and risk assessment approach for metals/metalloids are still mainly based on total or dissolved concentrations. However, it has been recognized that accurate assessment of the bio-available metal fraction is crucial, even if the way to incorporate bioavailability into these procedures is still under discussion. The speciation of a pollutant in the exposure medium is the first factor that regulates its bioavailability and consequently its bioaccumulation and the induced biological effects. Therefore, within any ecological risk assessment, bioavailability has obvious implications: firstly in exposure analysis which aim is to determine Predicted Exposure Concentration (PEC); secondly in effect analysis while deriving the so-called Predicted No-Effect Concentrations (PNEC) as toxicity is often linked to the amount of the contaminant incorporated into the tissues of biota. Similarities between metals/metalloids and radionuclides are limited to the biogeochemical behaviour of the element considered and to the need to use bioavailability models. In addition, for radionuclides, emitted ionising radiations (type and energy) need to be taken into account for both exposure and effect analyses whilst performing dosimetric calculations appropriate to the exposure scenarios. A methodology for properly implementing bioavailability models is explained and illustrated for aqueous U(VI), starting from a comprehensive review of the thermodynamic data relevant to environmentally-realistic physico-chemical conditions. Then, the use of thermodynamic equilibrium modelling as a tool for interpreting the bioavailability of U(VI) is presented. Using a systematic approach, different bioavailability models of increasing complexity were tested to model U bio

  7. Factors influencing zinc bioavailability in rats

    International Nuclear Information System (INIS)

    Mahalko, J.R.; Johnson, P.E.; Swan, P.B.

    1986-01-01

    The amount of Zn fed, its source, and the Zn status of experimental animals may affect Zn bioavailability. To test this, rats were fed doses of Zn from ZnCl 2 or from various foods labeled extrinsically. Three weeks before and after the test meal, rats were fed an AIN diet modified in Zn content. Absorption was calculated by monitoring whole body retention and extrapolating to zero time. In rats fed 12 ppm Zn and test doses of 6 to 275 μg, absorption decreased from 80 to 50%, and the amount absorbed increased quadratically (r 2 = 0.998), but turnover was unaffected. Rats fed 38 or 77 ppm Zn absorbed less of test doses of 290, 613, or 1700 μg Zn than did those fed 12 ppm, and their Zn turnover rate was higher. In two 2 x 7 factorial experiments, rats fed 12 or 38 ppm Zn were given 16 or 98 μg Zn from 7 Zn sources. Bioavailability from some foods was higher than from ZnCl 2 except in rats eating only 12 ppm Zn and receiving the small dose. There were greater differences in bioavailability among foods when tested at the higher Zn status or dose. This may explain inconsistencies seen in comparing Zn bioavailability by traditional growth assay with that seen in 65 Zn tracer studies. The authors conclude that Zn status of the experimental animal, as well as the amount of Zn and its source, will affect Zn bioavailability

  8. 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

  9. Bioavailability of nanoparticulate hematite to Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Marusenko, Yevgeniy; Shipp, Jessie; Hamilton, George A.; Morgan, Jennifer L.L.; Keebaugh, Michael; Hill, Hansina; Dutta, Arnab; Zhuo, Xiaoding; Upadhyay, Nabin; Hutchings, James; Herckes, Pierre; Anbar, Ariel D.; Shock, Everett; Hartnett, Hilairy E.

    2013-01-01

    The environmental effects and bioavailability of nanoparticulate iron (Fe) to plants are currently unknown. Here, plant bioavailability of synthesized hematite Fe nanoparticles was evaluated using Arabidopsis thaliana (A. thaliana) as a model. Over 56-days of growing wild-type A. thaliana, the nanoparticle-Fe and no-Fe treatments had lower plant biomass, lower chlorophyll concentrations, and lower internal Fe concentrations than the Fe-treatment. Results for the no-Fe and nanoparticle-Fe treatments were consistently similar throughout the experiment. These results suggest that nanoparticles (mean diameter 40.9 nm, range 22.3–67.0 nm) were not taken up and therefore not bioavailable to A. thaliana. Over 14-days growing wild-type and transgenic (Type I/II proton pump overexpression) A. thaliana, the Type I plant grew more than the wild-type in the nanoparticle-Fe treatment, suggesting Type I plants cope better with Fe limitation; however, the nanoparticle-Fe and no-Fe treatments had similar growth for all plant types. -- Highlights: ► Iron nanoparticles were synthesized and assessed for bioavailability to Arabidopsis. ► Arabidopsis grew better in the presence of EDTA-bound iron than nanoparticulate iron. ► Arabidopsis grew the same in the presence of nanoparticulate iron compared to no iron. -- Synthesized iron nanoparticles were not bioavailable to Arabidopsis thaliana in agar nutrient media

  10. 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.

  11. 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...

  12. 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...

  13. Phosphorous bioavailability along a soil chronosequence

    Science.gov (United States)

    Roberts, K.; Vokhshoori, N. L.; Rosenthanl, A.; Turner, B. L.; Condron, L.; Paytan, A.

    2011-12-01

    In humid environments, as soils age nutrient loss through leaching and chemical trasformations affect the succession and composition of the biological communities. In particular phosphorus (P), often a limiting nutrient in terrestrial systems, tends to evolve into less bio-available forms over time, compounding loss through leaching. Thus P availability has the potential to strongly affect community productivity and structure. Low standing stock of P may not necessarily imply P limitation as the bio-available P pool is continuously recycled and re-utilized. Thus extensive recycling can reduce to varying extents the effect of P limitation. The bio-availability and recycling rates of P are difficult to measure; multiple sequential extraction processes have been developed to try to define and quantify the bio-availability of both inorganic and organic forms of P. In this preliminary study, we will present results of P concentrations in different soil fractions and oxygen isotopes in phosphate. These data together increase our understanding of P dynamics as soils age. The work is being done with a well characterized and dated chronosequence from the west coast of the South Island of New Zealand near the Haast River.

  14. Nitric oxide bioavailability dysfunction involves in atherosclerosis.

    Science.gov (United States)

    Chen, Jing-Yi; Ye, Zi-Xin; Wang, Xiu-Fen; Chang, Jian; Yang, Mei-Wen; Zhong, Hua-Hua; Hong, Fen-Fang; Yang, Shu-Long

    2018-01-01

    The pathological characteristics of atherosclerosis (AS) include lipid accumulation, fibrosis formation and atherosclerotic plaque produced in artery intima, which leads to vascular sclerosis, lumen stenosis and irritates the ischemic changes of corresponding organs. Endothelial dysfunction was closely associated with AS. Nitric oxide (NO) is a multifunctional signaling molecule involved in the maintenance of metabolic and cardiovascular homeostasis. NO is also a potent endogenous vasodilator and enters for the key processes that suppresses the formation vascular lesion even AS. NO bioavailability indicates the production and utilization of endothelial NO in organisms, its decrease is related to oxidative stress, lipid infiltration, the expressions of some inflammatory factors and the alteration of vascular tone, which plays an important role in endothelial dysfunction. The enhancement of arginase activity and the increase in asymmetric dimethylarginine and hyperhomocysteinemia levels all contribute to AS by intervening NO bioavailability in human beings. Diabetes mellitus, obesity, chronic kidney disease and smoking, etc., also participate in AS by influencing NO bioavailability and NO level. Here, we reviewed the relationship between NO bioavailability and AS according the newest literatures. Copyright © 2017. Published by Elsevier Masson SAS.

  15. Enhanced bioavailability of opiates after intratracheal administration

    International Nuclear Information System (INIS)

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

    1986-01-01

    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

  16. Bioavailability of curcumin: problems and promises.

    Science.gov (United States)

    Anand, Preetha; Kunnumakkara, Ajaikumar B; Newman, Robert A; Aggarwal, Bharat B

    2007-01-01

    Curcumin, a polyphenolic compound derived from dietary spice turmeric, possesses diverse pharmacologic effects including anti-inflammatory, antioxidant, antiproliferative and antiangiogenic activities. Phase I clinical trials have shown that curcumin is safe even at high doses (12 g/day) in humans but exhibit poor bioavailability. Major reasons contributing to the low plasma and tissue levels of curcumin appear to be due to poor absorption, rapid metabolism, and rapid systemic elimination. To improve the bioavailability of curcumin, numerous approaches have been undertaken. These approaches involve, first, the use of adjuvant like piperine that interferes with glucuronidation; second, the use of liposomal curcumin; third, curcumin nanoparticles; fourth, the use of curcumin phospholipid complex; and fifth, the use of structural analogues of curcumin (e.g., EF-24). The latter has been reported to have a rapid absorption with a peak plasma half-life. Despite the lower bioavailability, therapeutic efficacy of curcumin against various human diseases, including cancer, cardiovascular diseases, diabetes, arthritis, neurological diseases and Crohn's disease, has been documented. Enhanced bioavailability of curcumin in the near future is likely to bring this promising natural product to the forefront of therapeutic agents for treatment of human disease.

  17. Enhanced bioavailable contaminant stripping (EBCS): metal bioavailability for evaluation of phytoextraction success

    OpenAIRE

    Petruzzelli, Gianniantonio; Pedron, Francesca; Gorini, Francesca; Pezzarossa, Beatrice; Tassi, Eliana; Barbafieri, Meri

    2013-01-01

    Phytoextraction may be applied at field scale when the removal of bioavailable metals is the specific target of the technology. Residual metals in soil can be considered substantially inert or to be evaluated by site specific risk analysis.

  18. Prebiotics increase heme iron bioavailability and do not affect non-heme iron bioavailability in humans.

    Science.gov (United States)

    Weinborn, Valerie; Valenzuela, Carolina; Olivares, Manuel; Arredondo, Miguel; Weill, Ricardo; Pizarro, Fernando

    2017-05-24

    The aim of this study was to establish the effect of a prebiotic mix on heme and non-heme iron (Fe) bioavailability in humans. To this purpose, twenty-four healthy women were randomized into one of two study groups. One group ate one yogurt per day for 12 days with a prebiotic mix (prebiotic group) and the other group received the same yogurt but without the prebiotic mix (control group). Before and after the intake period, the subjects participated in Fe absorption studies. These studies used 55 Fe and 59 Fe radioactive isotopes as markers of heme Fe and non-heme Fe, respectively, and Fe absorption was measured by the incorporation of radioactive Fe into erythrocytes. The results showed that there were no significant differences in heme and non-heme Fe bioavailability in the control group. Heme Fe bioavailability of the prebiotic group increased significantly by 56% post-prebiotic intake. There were no significant differences in non-heme Fe bioavailability in this group. We concluded that daily consumption of a prebiotic mix increases heme Fe bioavailability and does not affect non-heme iron bioavailability.

  19. Mineralogy affects geoavailability, bioaccessibility and bioavailability of zinc

    International Nuclear Information System (INIS)

    Molina, Ramon M.; Schaider, Laurel A.; Donaghey, Thomas C.; Shine, James P.; Brain, Joseph D.

    2013-01-01

    We correlated mineralogical and particle characteristics of Zn-containing particles with Zn geoavailability, bioaccessibility, and bioavailability following gavage and intranasal (IN) administration in rats. We compared samples of Zn/Pb mine waste and five pulverized pure-phase Zn minerals ( 65 Zn. We assessed geoavailability using sequential extractions and bioaccessibility using in vitro extraction tests simulating various pH and biological conditions. Zn in vivo bioavailability and in vitro bioaccessibility decreased as follows: mine waste > hydrozincite > hemimorphite > zincite ≈ smithsonite >> sphalerite. We found significant correlations among geoavailability, bioaccessibility and bioavailability. In particular, Zn bioavailability post-gavage and post-IN was significantly correlated with bioaccessibility in simulated phagolysosomal fluid and gastric fluid. These data indicate that solid phase speciation influences biological uptake of Zn and that in vitro tests can be used to predict Zn bioavailability in exposure assessment and effective remediation design. Highlights: •Zinc particle mineralogy influences bioaccessibility and bioavailability. •Zn bioavailability via gavage was 1.2–1.6 times higher than via intranasal route. •Zn particle geoavailability correlates with bioaccessibility. •In vitro bioaccessibility tests can predict in vivo Zn bioavailability. •Metal speciation and geochemical alterations can impact Zn bioavailability. -- Zinc mineralogy influences in vitro bioaccessibility and in vivo bioavailability and in vitro extraction tests can be used to predict Zn bioavailability from particles

  20. Bioavailability of indomethacin-saccharin cocrystals.

    Science.gov (United States)

    Jung, Min-Sook; Kim, Jeong-Soo; Kim, Min-Soo; Alhalaweh, Amjad; Cho, Wonkyung; Hwang, Sung-Joo; Velaga, Sitaram P

    2010-11-01

    Pharmaceutical cocrystals are new solid forms with physicochemical properties that appear promising for drug product development. However, the in-vivo bioavailability of cocrystals has rarely been addressed. The cocrystal of indomethacin (IND), a Biopharmaceutical Classification System class II drug, with saccharin (SAC) has been shown to have higher solubility than IND at all pH. In this study, we aimed to evaluate the in-vitro dissolution and in-vivo bioavailability of IND-SAC cocrystals in comparison with IND in a physical mixture and the marketed product Indomee. Scale-up of the cocrystals was undertaken using cooling batch crystallisation without seeding. The chemical and physical purity of the up-scaled material was verified using high-performance liquid chromatography, differential scanning calorimetry and powder X-ray diffraction. The IND-SAC cocrystals and IND plus SAC were mixed with lactose and the formulations were placed into gelatin capsules. In-vitro dissolution studies were then performed using the rotating basket dissolution method. The intrinsic dissolution rate of IND and IND-SAC cocrystals was also determined. Finally, a bioavailability study for the formulations was conducted in beagle dogs. The plasma samples were analysed using high-performance liquid chromatography and the pharmacokinetic data were analysed using standard methodologies.   The bulk cocrystals (i.e. scaled-up material) were chemically and physically pure. The in-vitro dissolution rate of the cocrystals was higher than that of IND and similar to that of Indomee at pH 7.4 and pH 1.2. The in-vivo bioavailability of the IND-SAC cocrystals in dogs was significantly higher (ANOVA, P0.05). The study indicates that the improved aqueous solubility of the cocrystals leads to improved bioavailability of IND. Thus, the cocrystals are a viable alternative solid form that can improve the dissolution rate and bioavailability of poorly soluble drugs. © 2010 The Authors. JPP © 2010 Royal

  1. Mobility and Bioavailability of Radionuclides in Soils

    International Nuclear Information System (INIS)

    Iurian, A.; Olufemi Phaneuf, M.; Mabit, L.

    2016-01-01

    It is crucial to understand the behavior of radionuclides in the environment, their potential mobility and bioavailability related to long-term persistence, radiological hazards, and impact on human health. Such key information is used to develop strategies that support policy decisions. The environmental behavior of radionuclides depends on ecosystem characteristics. A given soil’s capacity to immobilize radionuclides has been proved to be the main factor responsible for their resulting activity concentrations in plants. The mobility and bioavailability of radionuclides in soils is complex, depending on clay-sized soil fraction, clay mineralogy, organic matter, cation exchange capacity, pH and quantities of competing cations. Moreover, plant species have different behaviors regarding radionuclide absorption depending on soil and plan characteristics

  2. Bioavailability and variability of biphasic insulin mixtures

    DEFF Research Database (Denmark)

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

    2012-01-01

    Absorption of subcutaneously administered insulin is associated with considerable variability. Some of this variability was quantitatively explained for both soluble insulin and insulin suspensions in a recent contribution to this journal (Søeborg et al., 2009). In the present article......, 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...... insulin degradation. Soluble insulins are assumed to be degraded enzymatically in the subcutaneous tissue. Suspended insulin crystals form condensed heaps that are assumed to be degraded from their surface by invading macrophages. It is demonstrated how the shape of the heaps affects the absorption...

  3. 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.

  4. 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 ...

  5. KIRLIANOGRAPHY ESTIMATION OF BIOAVAILABILITY OF SUBSTANCE

    Directory of Open Access Journals (Sweden)

    M. V. Kuryk

    2013-11-01

    The method of classical kirlianography with X ray film allows assessing the bioavailability condition, which is important for the prediction of absorption and physiological effects of a man consumed food and phytomedicines. Therefore, these studies are relevant and require further development. Used such standard methods of mathematical processing as histograms and pixel brightness profile for the analysis of Kirlian images are informative enough for the individual samples, and can be the basis for the batch processing of data.

  6. Bioavailability of cadmium from linseed and cocoa

    DEFF Research Database (Denmark)

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

    2014-01-01

    The exposure of the European population to cadmium from food is high compared with the tolerable weekly intake of 2.5 μg/kg bodyweight set by EFSA in 2009. Only few studies on the bioavailability of cadmium from different food sources has been performed but this information in very important...... 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...... 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...

  7. 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.

  8. Rapid screening assay for calcium bioavailability studies

    International Nuclear Information System (INIS)

    Luhrsen, K.R.; Hudepohl, G.R.; Smith, K.T.

    1986-01-01

    Calcium bioavailability has been studied by numerous techniques. The authors report here the use of the gamma emitting isotope of calcium ( 47 Ca) in a whole body retention assay system. In this system, calcium sources are administered by oral gavage and subsequent counts are determined and corrected for isotopic decay. Unlike iron and zinc retention curves, which exhibit a 2-3 day equilibration period, calcium reaches equilibration after 24 hours. Autoradiographic analysis of the femurs indicate that the newly absorbed calcium is rapidly distributed to the skeletal system. Moreover, the isotope is distributed along the entire bone. Comparisons of calcium bioavailability were made using intrinsic/extrinsic labeled milk from two species i.e. rat and goat as well as CaCO 3 . In addition, extrinsic labeled cow milk was examined. In the rat, the extrinsic labeled calcium from milk was better absorbed than the intrinsic calcium. This was not the case in goat milk or the calcium carbonate which exhibited no significant differences. Chromatographic analysis of the labeled milk indicates a difference in distribution of the 47 Ca. From these data, the authors recommend the use of this assay system in calcium bioavailability studies. The labeling studies and comparisons indicate caution should be used, however, in labeling techniques and species milk comparison

  9. 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

    2013-01-01

    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. PMID:22897361

  10. Incorporation of Heavy metals bioavailability into risk characterization

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Hyerim; Chung, Jae Shik; Nam, Taekwoo; Nam, Kyoungphile [Department of Civil and Environmental Engineering, Seoul National University, Seoul (Korea, Republic of); Moon, Hee Sun [School of Earth and Environmental Sciences, Seoul National University, Seoul (Korea, Republic of)

    2010-09-15

    The bioavailability of field-aged Cd and Cu was calculated, and compared to the total concentrations determined by acid digestion. Only 0.60-4.15% for Cd and 0.59-9.43% for Cu were found to be bioavailable when determined by stomach-phase extraction. The incorporation of bioavailability reduced more than 90% of the calculated risk of the metals at the site of study. It should be noted that such a reduction may not be generalized and the site-specific bioavailability needs to be determined case by case. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  11. The bioavailability of chemicals in soil for earthworms

    Science.gov (United States)

    Lanno, R.; Wells, J.; Conder, Jason M.; Bradham, K.; Basta, N.

    2004-01-01

    The bioavailability of chemicals to earthworms can be modified dramatically by soil physical/chemical characteristics, yet expressing exposure as total chemical concentrations does not address this problem. In order to understand the effects of modifying factors on bioavailability, one must measure and express chemical bioavailability to earthworms in a consistent, logical manner. This can be accomplished by direct biological measures of bioavailability (e.g., bioaccumulation, critical body residues), indirect biological measures of bioavailability (e.g., biomarkers, reproduction), or indirect chemical measures of bioavailability (e.g., chemical or solid-phase extracts of soil). If indirect chemical measures of bioavailability are to be used, they must be correlated with some biological response. Bioavailability can be incorporated into ecological risk assessment during risk analysis, primarily in the estimation of exposure. However, in order to be used in the site-specific ecological risk assessment of chemicals, effects concentrations must be developed from laboratory toxicity tests based on exposure estimates utilizing techniques that measure the bioavailable fraction of chemicals in soil, not total chemical concentrations. ?? 2003 Elsevier Inc. All rights reserved.

  12. Bioavailability of diclofenac potassium at low doses

    Science.gov (United States)

    Hinz, Burkhard; Chevts, Julia; Renner, Bertold; Wuttke, Henrike; Rau, Thomas; Schmidt, Andreas; Szelenyi, Istvan; Brune, Kay; Werner, Ulrike

    2005-01-01

    Aim Diclofenac-K has been recently launched at low oral doses in different countries for over-the-counter use. However, given the considerable first-pass metabolism of diclofenac, the degree of absorption of diclofenac-K at low doses remained to be determined. The aim of this study was to determine the bioavailability of low-dose diclofenac-K. Methods A randomized, three-way, cross-over study was performed in 10 subjects. Each received diclofenac-K, 22.5 mg via short-term i.v. infusion and orally at single doses of 12.5 mg and 25 mg. Results Mean (± SD) times to maximal plasma concentration (tmax) of diclofenac were 0.48 ± 0.28 h (12.5 mg) and 0.93 ± 0.96 h (25 mg). The absolute bioavailability of diclofenac-K after oral administration did not differ significantly in the 12.5-mg and 25-mg dose group (63.1 ± 12.6% vs. 65.1 ± 19.4%, respectively). The 90% confidence intervals for the AUC∞ and AUCt ratios for the two oral regimes were 82.6, 103.4% (point estimate 92.4%) and 86.2, 112.9% (point estimate 98.6%), respectively. These values were within the acceptance criteria for bioequivalence (80–125%). Conclusions Our data indicate that diclofenac-K is rapidly and well absorbed at low dose, and are consistent with a rapid onset of action of the drug. Abbreviations AUC, area under plasma concentraton-time curve; Cmax, peak plasma concentration; CI, confidence interval; COX, cyclooxygenase; D, dose; F, absolute bioavailability; tmax, time to reach Cmax. PMID:15606444

  13. Atovaquone oral bioavailability enhancement using electrospraying technology.

    Science.gov (United States)

    Darade, Aditya; Pathak, Sulabha; Sharma, Shobhona; Patravale, Vandana

    2018-01-01

    Atovaquone in combination with proguanil hydrochloride, marketed as Malarone® tablets by GlaxoSmithKline (GSK), is prescribed for the treatment of malaria. High dose and poor bioavailability are the main hurdles associated with atovaquone oral therapy. The present study reports development of atovaquone nanoparticles, using in house designed and fabricated electrospraying equipment, and the assessment of bioavailability and therapeutic efficacy of the nanoparticles after oral administration. Solid nanoparticles of atovaquone were successfully produced by electrospraying and were characterized for particle size and flow properties. Differential Scanning Calorimetry, X-ray Diffraction, Fourier Transform Infrared Spectroscopy studies were also carried out. Atovaquone nanoparticles along with proguanil hydrochloride and a suitable wetting agent were filled in size 2 hard gelatin capsules. The formulation was compared with Malarone® tablets (GSK) and Mepron® suspension (GSK) in terms of in vitro release profile and in vivo pharmacokinetic studies. It showed 2.9-fold and 1.8-fold improved bioavailability in rats compared to Malarone® tablets and Mepron® suspension respectively. Therapeutic efficacy of the formulation was determined using modified Peter's 4-day suppressive tests and clinical simulation studies using Plasmodium berghei ANKA infected Swiss mice and compared to Malarone®. The developed formulation showed a 128-fold dose reduction in the modified Peter's 4-day suppressive tests and 32-fold dose reduction in clinical simulation studies. Given that only one capsule a day of developed formulation is required to be administered orally compared to 4 Malarone® tablets once a day and that too at a significantly reduced dose, this nanoparticle formulation will definitely reduce the side-effects of the treatment and is also likely to increase patient compliance. Copyright © 2017. Published by Elsevier B.V.

  14. Extraction, bioavailability, and bioefficacy of capsaicinoids.

    Science.gov (United States)

    Lu, Muwen; Ho, Chi-Tang; Huang, Qingrong

    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 addition, the pharmacological effects and their underlying mechanisms are also studied. Copyright © 2016. Published by Elsevier B.V.

  15. Animal bioavailability of defined xenobiotic lignin metabolites

    International Nuclear Information System (INIS)

    Sandermann, H. Jr.; Arjmand, M.; Gennity, I.; Winkler, R.; Struble, C.B.; Aschbacher, P.W.

    1990-01-01

    Lignin has been recognized as a major component of bound pesticide residues in plants and is thought to be undigestible in animals. Two defined ring-U- 14 C-labeled chloroaniline/lignin metabolites have now been fed to rats, where a release of ∼66% of the bound xenobiotic occurred in the form of simple chloroaniline derivatives. The observed high degree of bioavailability indicates that bound pesticidal residues may possess ecotoxicological significance. In parallel studies, the white-rot fungus Phanerochaete chrysosporium was more efficient, and a soil system was much less efficient, in the degradation of the [ring-U- 14 C]chloroaniline/lignin metabolites

  16. Enhanced Bioavailable Contaminant Stripping (EBCS: metal bioavailability for evaluation of phytoextraction success

    Directory of Open Access Journals (Sweden)

    Petruzzelli G.

    2013-04-01

    Full Text Available Phytoextraction may be applied at field scale when the removal of bioavailable metals is the specific target of the technology. Residual metals in soil can be considered substantially inert or to be evaluated by site specific risk analysis.

  17. Influence of lifestyle on vitamin bioavailability.

    Science.gov (United States)

    van den Berg, Henk; van der Gaag, Martijn; Hendriks, Henk

    2002-01-01

    In this review the effects of lifestyle factors, especially alcohol consumption, on vitamin bioavailability are summarized and discussed. Alcohol effects are clearly dose-dependent. Excessive chronic alcohol intake is generally associated with vitamin deficiency (especially folate, thiamine, and vitamin B6) due to malnutrition, malabsorption, and ethanol toxicity. Effects of moderate alcohol use are mainly explained by a lower vitamin intake. In the case of vitamin A and beta-carotene, effects on post-absorptive (lipoprotein) metabolism have been demonstrated. In one diet-controlled crossover study, alcohol consumption resulted in an increase in the plasma vitamin B6 (PLP) content, especially after beer consumption (containing vitamin B6), but also after wine and spirit consumption (not containing vitamin B6). Smoking is also associated with a lower dietary vitamin intake. In the case of vitamin C, B12, folate, and beta-carotene, evidence has been presented for effects on postabsorptive metabolism, due to smoke-induced oxidative stress and/or vitamin inactivation. For vitamin E a direct effect of smoking on absorption has been demonstrated. There is no convincing evidence that low-fat diets negatively affect fat-soluble vitamin absorption, but cholesterol-lowering compounds (diets), or unabsorbable fat substitutes, may do so. Vitamin bioavailability may be compromised from certain vegetables (particularly raw), and/or from high-fiber foods, because of limited digestion and inefficient release of vitamins from the food matrix.

  18. Solubility and bioavailability improvement of pazopanib hydrochloride.

    Science.gov (United States)

    Herbrink, Maikel; Groenland, Stefanie L; Huitema, Alwin D R; Schellens, Jan H M; Beijnen, Jos H; Steeghs, Neeltje; Nuijen, Bastiaan

    2018-06-10

    The anti-cancer drug pazopanib hydrochloride (PZH) has a very low aqueous solubility and a variable oral bioavailability. A new pharmaceutical formulation with an improved solubility may enhance the bioavailability and reduce the variability. A broad selection of polymer excipients was tested for their compatibility and solubilizing properties by conventional microscopic, thermal and spectrometric techniques. A wet milling and mixing technique was used to produce homogenous powder mixtures. The dissolution properties of the formulation were tested by a pH-switch dissolution model. The final formulation was tested in vivo in cancer patient following a dose escalation design. Of the tested mixture formulations, the one containing the co-block polymer Soluplus® in a 8:1 ratio with PZH performed best in terms of in vitro dissolution properties. The in vivo results indicated that 300 mg of the developed formulation yields similar exposure and a lower variability (379 μg/mL∗h (36.7% CV)) than previously reported values for the standard PZH formulation (Votrient®) at the approved dose of 800 mg. Furthermore, the expected plasma-C through levels (27.2 μg/mL) exceeds the defined therapeutic efficacy threshold of 20 μg/mL. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. 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...

  20. Protein and amino acid bioavailability estimates for canine foods

    NARCIS (Netherlands)

    Hendriks, W.H.; Bakker, E.J.; Bosch, G.

    2015-01-01

    Estimates of nutrient bioavailability are required for establishing dietary nutrient requirements and to evaluate the nutritional value of food ingredients or foods that are exposed to processing or extended storage. This study aimed to generate estimates for the bioavailability of dietary CP and AA

  1. The bioavailability of oxalate from Oca (Oxalis tuberosa).

    Science.gov (United States)

    Albihn, P B; Savage, G P

    2001-08-01

    It is believed that soluble oxalate has higher bioavailability than insoluble oxalate. Oca (Oxalis tuberosa) is moderately high in oxalate and contains oxalate in soluble form only. We estimated the bioavailability of oxalate in oca based on the urinary excretion of oxalate after oxalate loading with oca to estimate the bioavailability of oxalate in oca. We also clarified whether bioavailability differs in various oxalate loads from the same food source and studied the effect of an additional calcium source on the bioavailability of oxalate from oca. Four men and 4 women ingested 50, 100 and 150 gm. oca as well as 100 gm. oca with 100 gm. sour cream. Oxalate was measured in a 6-hour urine sample from each volunteer. The mean bioavailability of oxalate from oca plus or minus standard deviation was 1.44% +/- 1.31% during the 6-hour period after intake. There was no significant difference in oxalate bioavailability among oxalate intake levels in this study, although oca consumption with sour cream significantly decreased the uptake of oxalate (p oca appears to be similar to that in spinach. However, bioavailability varies among individuals and depends on other constituents of a combined meal.

  2. Computational modeling of human oral bioavailability: what will be next?

    Science.gov (United States)

    Cabrera-Pérez, Miguel Ángel; Pham-The, Hai

    2018-06-01

    The oral route is the most convenient way of administrating drugs. Therefore, accurate determination of oral bioavailability is paramount during drug discovery and development. Quantitative structure-property relationship (QSPR), rule-of-thumb (RoT) and physiologically based-pharmacokinetic (PBPK) approaches are promising alternatives to the early oral bioavailability prediction. Areas covered: The authors give insight into the factors affecting bioavailability, the fundamental theoretical framework and the practical aspects of computational methods for predicting this property. They also give their perspectives on future computational models for estimating oral bioavailability. Expert opinion: Oral bioavailability is a multi-factorial pharmacokinetic property with its accurate prediction challenging. For RoT and QSPR modeling, the reliability of datasets, the significance of molecular descriptor families and the diversity of chemometric tools used are important factors that define model predictability and interpretability. Likewise, for PBPK modeling the integrity of the pharmacokinetic data, the number of input parameters, the complexity of statistical analysis and the software packages used are relevant factors in bioavailability prediction. Although these approaches have been utilized independently, the tendency to use hybrid QSPR-PBPK approaches together with the exploration of ensemble and deep-learning systems for QSPR modeling of oral bioavailability has opened new avenues for development promising tools for oral bioavailability prediction.

  3. ASSESSING SOIL ARSENIC BIOAVAILABILITY IN THE LABORATORY MOUSE

    Science.gov (United States)

    Variation among soils in the bioavailability of arsenic can be a critical determinant of the risk posed by exposure to these soils. Although in vitro techniques can provide vital data on aspects of bioavailability of metals and metalloids from soils, these results must be valida...

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

    Science.gov (United States)

    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 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. PMID:20200261

  5. Bioavailability of magnetic nanoparticles to the brain

    International Nuclear Information System (INIS)

    Huang, B.-R.; Chen, P.-Y.; Huang, C.-Y.; Jung, S.-M.; Ma, Y.-H.; Wu, Tony; Chen, J.-P.; Wei, K.-C.

    2009-01-01

    This study investigates the bioavailability of carboxymethyl dextran-coated magnetic nanoparticles (CMD-MNP) to the brain. The cytotoxicity of CMD-MNP was assessed by co-culture with C6, a rat glioma cell line. To investigate the effects of an external magnetic field on the biodistribution of nanoparticles in a rat model, a magnet of 0.3 Tesla was applied externally over the cranium and the particles injected via the external jugular vein. Nanoparticles were also injected into rats implanted with C6 tumor cells. Staining of histological samples with Prussian blue to detect iron particles revealed that the external magnetic field enhanced the aggregation of nanoparticles in the rat brain; this enhancement was even more pronounced in the tumor region.

  6. Biodisponibilidade do licopeno Bioavailability of lycopene

    Directory of Open Access Journals (Sweden)

    Bettina Moritz

    2006-04-01

    Full Text Available Esta revisão procura reunir diversos estudos que avaliam os fatores que influenciam a biodisponibilidade do licopeno, bem como os alimentos fontes e a recomendação de ingestão desse carotenóide. Para tanto, foi realizado um levantamento bibliográfico, mediante consulta às bases de dados Medline (National Library of Medicine, USA e Lilacs (Bireme, Brasil nas quais foram selecionadas publicações científicas em português e inglês, nos últimos quinze anos, que utilizaram os temas: licopeno, carotenóides e/ou biosponibilidade. O licopeno é um carotenóide sem atividade de pró-vitamina A, mas um potente antioxidante, sendo essa função possivelmente associada à redução do risco da ocorrência do câncer e certas doenças crônicas. Esse nutriente é encontrado em um número limitado de alimentos, e, além disso, o organismo não é capaz de sintetizá-lo; dessa forma, o licopeno é obtido exclusivamente por meio da dieta alimentar. A quantidade sugerida de ingestão de licopeno varia de 4 a 35mg/dia. Estudos mostram que existem vários fatores que podem interferir na biodisponibilidade do licopeno, tais como absorção intestinal, quantidade de licopeno no alimento fonte, formas de apresentação (isômeros e sintéticos, presença da matriz alimentar, presença de outros nutrientes na refeição (como gordura, fibra, outros carotenóides, entre outros, ingestão de drogas, processamento do alimento, além da individualidade biológica e do estado nutricional do indivíduo. Estudos da biodisponibilidade do licopeno têm sido desenvolvidos a partir do tomate e seus produtos, por esse ser a fonte mais comumente consumida. O desenvolvimento do estudo enfatizou a importância da melhor forma de absorção desse nutriente, relevante que é para a prevenção de inúmeras doenças.This review collets several papers that evaluated the factors that influence the bioavailability of licopene, as well as the food sources of this nutrient and

  7. Bioavailability of magnetic nanoparticles to the brain

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B.-R. [Department of Neurosurgery, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 5 Fushing Street, Kweishan, Taoyuan 333, Taiwan (China); Chen, P.-Y. [Department of Neurosurgery, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 5 Fushing Street, Kweishan, Taoyuan 333, Taiwan (China); Graduate Institute of Biomedical Sciences, Chang-Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Taoyuan 333, Taiwan (China); Huang, C.-Y. [Department of Neurosurgery, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 5 Fushing Street, Kweishan, Taoyuan 333, Taiwan (China); Jung, S.-M. [Department of Pathology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 5 Fushing Street, Kweishan, Taoyuan 333, Taiwan (China); Ma, Y.-H. [Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan 333, Taiwan (China); Wu, Tony [Department of Neurology, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, 5 Fushing Street, Kweishan, Taoyuan 333, Taiwan (China); Chen, J.-P. [Department of Chemical and Material Engineering, College of Medicine, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan 333, Taiwan (China)], E-mail: jpchen@mail.cgu.edu.tw; Wei, K.-C. [Department of Neurosurgery, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 5 Fushing Street, Kweishan, Taoyuan 333, Taiwan (China)], E-mail: kuochenwei@adm.cgmh.org.tw

    2009-05-15

    This study investigates the bioavailability of carboxymethyl dextran-coated magnetic nanoparticles (CMD-MNP) to the brain. The cytotoxicity of CMD-MNP was assessed by co-culture with C6, a rat glioma cell line. To investigate the effects of an external magnetic field on the biodistribution of nanoparticles in a rat model, a magnet of 0.3 Tesla was applied externally over the cranium and the particles injected via the external jugular vein. Nanoparticles were also injected into rats implanted with C6 tumor cells. Staining of histological samples with Prussian blue to detect iron particles revealed that the external magnetic field enhanced the aggregation of nanoparticles in the rat brain; this enhancement was even more pronounced in the tumor region.

  8. Bioavailability of cadmium from soy isolate

    International Nuclear Information System (INIS)

    Lee, Y.H.; Fox, M.R.S.; Tao, S.H.

    1986-01-01

    Studies with 109 Cd showed that more Cd was taken up by duodenum (D) and jejunum-ileum (J-I) of Japanese Quail (JQ) with soy isolate (SI) than with casein gelatin (CG) diet. The purpose of this study was to compare the bioavailability of endogenous Cd from SI with CdCl 2 added to a CG diet. Day-old JQ were fed either SI or CG diet containing 121 ppb of Cd. Beginning at 7 d of age, 109 CdCl 2 was incorporated into both diets at 100 uci/kg and a group of birds from each diet was killed on 8, 9, 11, 14 and 21 d. Growth was normal with both diets and food intake was similar. Cd concentration (determined by ICAP and AAS furnace) was significantly higher with CG than with SI on all days in D and up to 11 d of age in J-I. Although much less Cd accumulated in liver and kidneys than in D and J-I, the levels were also higher with CG. Total Cd uptake by liver and kidneys increased gradually with CG whereas there was little increase with SI. Specific activity of Cd in D and J-I with CG remained the same throughout the experiment, but increased significantly with SI up to 11 d of age. The specific activity of Cd in liver and kidneys from both CG and SI increased with time but the rate was greater with SI. The patterns of specific activity indicate differences among tissues and between CG and SI for time required to reach equilibrium between 109 Cd and non-radioactive Cd. These data also show that endogenous Cd in SI is less bioavailable than CdCl 2 added to CG diet

  9. Gender differences on bioavailability of ofloxacin

    International Nuclear Information System (INIS)

    Hassan, Z.U.; Naseer, R.

    2008-01-01

    The fluoroquinolones are currently enjoying extensive worldwide clinical applications because of their good bioavailability and pharmacokinetic profile. Investigation into several aspects of the pharmacokinetic of all clinically relevant fluoroquinolones, have been carried out notably in Europe, USA and Japan. In view of the geonetical (geographical influences on genetics-pharmacogenetics) differences, it is important that for the optimal therapeutic outcome, biodisposition studies on drugs are better conducted in the population and environments where wide and extensive use of the drug is anticipated. The Objectives of study were to see the pharmacokinetic parameters in healthy young male and female volunteers. This comparative study was conducted King Edward Medical University, Lahore, Pakistan, from July 2005 to December 2005. In Pakistan where the use of antibiotics is more frequent by the general practitioners it is important to elucidate certain dose parameters it is also noticed that side effects are more in females than males so present study is conducted to calculate any differences in bioavailability on the basis of sex. The pharmacokinetic parameters of ofloxacin were determined in each of the clinically health eight young girls and boys (mean age 23.9 and 25.1 years, respectively) following a single oral dose of 400 mg tablet. The method adopted was microbiological assay. The blood samples collected at predetermined time intervals after drug administration revealed almost twice as high concentration of the drug in plasma of the girls than that in the boys. The pharmacokinetic parameters revealed significantly (p<0.01) higher values for area under curve (AUC) and Cmax, and lower total body clearance (TBC) and volume of distribution in the girls than in the boys. The gender differences in pharmacokinetic parameters indicate that the dose adjustment should be considered in male and female. (author)

  10. Assessing the bioavailability and risk from metal-contaminated ...

    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, contamination may arise from multiple sources of toxic elements that may exist as different forms (species) which impact bioavailability. In turn, the bioaccessibility/bioavailability of soil and dust contaminants has a direct impact on human health risk assessment and risk management practices. Novel research efforts focusing on development and application of in vitro and in vivo methods to measure the bioaccessibility/bioavailability of metal contaminated soils have advanced in the past few years. The objective of this workshop was to focus on recent developments in assessing the bioaccessibility/bioavailability of arsenic contaminated soils, metal contamination in urban residences in Canada and potential children’s exposures to toxic elements in house dust, a community-based study known as the West Oakland Residential Lead Assessment , studies of the bioavailability of soil cadmium, chromium, nickel and mercury and human exposures to contaminated Brownfield soils. These presentations covered issues related to human health and bioavailability along with the most recent studies on community participation in assessing metal contamination, studies of exposures to residential contamination, and

  11. Bioavailability of zinc, copper, and manganese from infant diets

    International Nuclear Information System (INIS)

    Bell, J.G.

    1987-01-01

    A series of trace element absorption experiments were performed using the Sprague-Dawley suckling rat put and infant rhesis monkey (Macaca mulatta) with extrinsic radiolabeling to assess the bioavailability of Zn, Cu, and Mn from infant diets and to examine specific factors that affect absorption of these essential nutrients. Bioavailability of Cu as assessed by 6 h liver uptake (% of 64 Cu dose) was highest from human milk and cow milk based formula and significantly lower from cow milk and soy based formula. Copper bioavailability from infant cereal products as assessed by whole body uptake (% of 64 Cu dose) in d 20 rats, 9 h postintubation, was low compared to the bioavailability from cow milk or human milk alone. 65 Zn uptake in d 20 rats, 9 h postintubation, was significantly lower from cereals fed alone or in combination with cow or human milk as compared to the uptake from the milks fed alone. Zn bioavailability varied among cereal diets, (lowest from cereals containing phytate and highest from cereal/fruit products). Mn bioavailability from infant diets was assessed using a modified suckling rat pup model. Bioavailability (24 h whole body retention of 54 Mn) was high from all milks and commercial formulas tested

  12. The effect of dietary factors on strawberry anthocyanins oral bioavailability.

    Science.gov (United States)

    Xiao, Di; Sandhu, Amandeep; Huang, Yancui; Park, Eunyoung; Edirisinghe, Indika; Burton-Freeman, Britt M

    2017-11-15

    Strawberries are a dietary source of anthocyanins, particularly pelargonidin glycosides. Dietary anthocyanins have received increasing attention among researchers and consumers due to their health benefits. The oral bioavailability of anthocyanins is reported to be low and various dietary factors may influence their oral bioavailability further. Milk is suggested to reduce (poly)phenols' oral bioavailability. However, the effect of milk on anthocyanin oral bioavailability remains uncertain. Likewise, mixed nutrient meals may influence the oral bioavailability of anthocyanins. Therefore, the purpose of this study was to assess the effect of milk on the oral bioavailability and other pharmacokinetic (PK) variables of strawberry anthocyanins consumed with and without a meal. Nine healthy participants consumed a strawberry beverage prepared in milk or water with a standard meal on two occasions. On two additional occasions, the beverages were given to a subset (n = 4) of participants to determine the impact of the meal on anthocyanin PK variables, including oral bioavailability. Independent of the meal, beverages prepared in milk significantly reduced the peak plasma concentrations (C max ) of pelargonidin-3-O-glucoside (P-3-G), pelargonidin-glucuronide (PG) and pelargonidin-3-O-rutinoside (P-3-R), as well as the PG and P-3-R area under the curve (AUC) (p bioavailability of pelargonidin anthocyanins under meal conditions; however, the oral relative bioavailability of pelargonidin anthocyanins was reduced by ∼50% by milk under without meal conditions (p < 0.05). Consuming strawberry beverages made with milk and consuming those made with water with and without a meal influenced different aspects of strawberry anthocyanin PKs. The significance of this effect on clinical efficacy requires additional research.

  13. 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. © 2012 Nestec S. A.. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

  14. 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.

  15. Food synergies for improving bioavailability of micronutrients from plant foods.

    Science.gov (United States)

    Nair, K Madhavan; Augustine, Little Flower

    2018-01-01

    Plant foods are endowed with micronutrients but an understanding of bioavailability is essential in countries primarily dependent on plant based foods. Bioavailability depends majorly on food synergies. This review examines the nature of certain food synergies and methods to screen and establish it as a strategy to control micronutrient deficiency in the populations. Strong evidence on the synergistic effect of inclusion of vitamin C rich fruits and non-vegetarian foods in enhancing the bioavailability of iron has been demonstrated. Fat is found to be synergistic for vitamin A absorption. Red wine and protein have been explored for zinc absorption and effect of fat has been studied for vitamin D. Methods for screening of bioavailability, and biomarkers to demonstrate the synergistic effects of foods are required. Translation of food synergy as a strategy requires adaptation to the context and popularization of intelligent food synergies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Development of Bioavailability Adjustment Factors: A Feasibility Study

    National Research Council Canada - National Science Library

    Rembish, Steve

    2000-01-01

    The primary purpose of this effort is to investigate the feasibility of developing and using bioavailability adjustment factors to modify intake assumptions used in risk assessments on a site-specific basis...

  17. From bioavailability science to regulation of organic chemicals

    NARCIS (Netherlands)

    Ortega-Calvo, J.J.; Harmsen, J.; Parsons, J.R.; Semple, K.T.; Aitkin, M.D.; Ajao, C.; Eadsforth, C.; Galay-Burgos, M.; Naidu, R.; Oliver, R.; Peijnenburg, W.J.G.M.; Römbke, J.; Streck, G.; Versonnen, B.

    2015-01-01

    The bioavailability of organic chemicals in soil and sediment is an important area of scientific investigation for environmental scientists, although this area of study remains only partially recognized by regulators and industries working in the environmental sector. Regulators have recently

  18. Flavanol plasma bioavailability is affected by metabolic syndrome in rats

    NARCIS (Netherlands)

    Margalef, M.; Pons, Z.; Iglesias-Carres, L.; Bravo, F.I.; Muguerza, B.; Arola-Arnal, A.

    2017-01-01

    Flavanols, which exert several health benefits, are metabolized after ingestion. Factors such as the host physiological condition could affect the metabolism and bioavailability of flavanols, influencing their bioactivities. This study aimed to qualitatively evaluate whether a pathological state

  19. Candesartan cilexetil loaded nanodelivery systems for improved oral bioavailability.

    Science.gov (United States)

    Dudhipala, Narendar; Veerabrahma, Kishan

    2017-02-01

    Candesartan cilexetil (CC), an antihypertensive drug, has low oral bioavailability due to poor solubility and hepatic first-pass metabolism. These are major limitations in oral delivery of CC. Several approaches are known to reduce the problems of solubility and improve the bioavailability of CC. Among various approaches, nanotechnology-based delivery of CC has potential to overcome the challenges associated with the oral administration. This review focuses on various nano-based delivery systems available and tried for improving the aqueous solubility, dissolution and consequently bioavailability of CC upon oral administration. Of all, solid lipid nanoparticles appear to be promising delivery system, based on current reported results, for delivery of CC, as this system improved the oral bioavailability and possessed prolonged pharmacodynamic effect.

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

    DEFF Research Database (Denmark)

    Mu, Huiling; Müllertz, Anette

    2015-01-01

    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....... In vitro studies provided a mechanistic understanding on the varied bioavailability caused by different lipid structures, the lower relative bioavailability of omega-3 fatty acids from FAEE formulation was closely related to the slower digestion rate of FAEE. Microencapsulated fish oil has often been used...... as a food additive because of its better chemical stability; studies showed that microencapsulation did not affect the bioavailability significantly. Even though food structures also affect the digestion and absorption of omega-3 containing lipids, several studies have shown that long-term intake of fish...

  1. Iron bioavailability: UK Food Standards Agency workshop report.

    Science.gov (United States)

    Singh, Mamta; Sanderson, Peter; Hurrell, Richard F; Fairweather-Tait, Susan J; Geissler, Catherine; Prentice, Ann; Beard, John L

    2006-11-01

    The UK Food Standards Agency convened a group of expert scientists to review current research investigating factors affecting iron status and the bioavailability of dietary iron. Results presented at the workshop show menstrual blood loss to be the major determinant of body iron stores in premenopausal women. In the presence of abundant and varied food supplies, the health consequences of lower iron bioavailability are unclear and require further investigation.

  2. Bioavailability of syrup and tablet formulations of cefetamet pivoxil.

    Science.gov (United States)

    Ducharme, M P; Edwards, D J; McNamara, P J; Stoeckel, K

    1993-12-01

    Two studies examining the bioavailability of cefetamet pivoxil in healthy male subjects were conducted. In the first, the bioavailabilities of the 250-mg (M250) and M500 tablet formulations of cefetamet pivoxil to be marketed were compared with that of a tablet used in clinical trials. All products were given with food at a dose of 500 mg. In the second study, the bioavailability of the syrup formulation was evaluated under both fasting and nonfasting conditions and compared with that of the M500 tablet formulation given with food. The absolute bioavailabilities of the M500 and M250 tablets (55.0% +/- 8.0% and 55.7% +/- 7.0%, respectively) were not significantly different from that of the clinical-trial formulation (49.8% +/- 8.5%). The newer tablet formulations exhibited faster absorption as evidenced by higher peak concentrations (3.8 [M500] and 3.9 [M250] mg/liter compared with 3.2 mg/liter for the clinical-trial formulation), a shorter time to peak concentration, and a shorter mean absorption time. The syrup formulation was found to have significantly lower absolute bioavailability (37.9% +/- 6.0%) compared with that of the M500 tablet (58.4% +/- 9.0%) when both were given with food. Food had no significant effect on the bioavailability of the syrup, which averaged 34.0% +/- 8.6% under fasting conditions, although absorption was delayed by food (mean absorption time increased from 2.2 to 3.9 h). This contrasts with the results of previous studies documenting significant increases in tablet bioavailability with food. Despite the lower bioavailability of the syrup, unbound-cefetamet concentrations are expected to remain above the MICs for 90% of the strains tested for susceptible organisms for approximately 10 h of the usual 12-h dosing interval with both syrup and tablet formulations of cefetamet pivoxil given with food.

  3. 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.

  4. Evaluation of Iodine Bioavailability in Seaweed Using in Vitro Methods.

    Science.gov (United States)

    Domínguez-González, M Raquel; Chiocchetti, Gabriela M; Herbello-Hermelo, Paloma; Vélez, Dinoraz; Devesa, Vicenta; Bermejo-Barrera, Pilar

    2017-09-27

    Due to the high levels of iodine present in seaweed, the ingestion of a large amount of this type of food can produce excessive intake of iodine. However, the food after ingestion undergoes different chemistry and physical processes that can modify the amount of iodine that reaches the systemic circulation (bioavailability). Studies on the bioavailability of iodine from food are scarce and indicate that the bioavailable amount is generally lower than ingested. Iodine in vitro bioavailability estimation from different commercialized seaweed has been studied using different in vitro approaches (solubility, dialyzability, and transport and uptake by intestinal cells). Results indicate that iodine is available after gastrointestinal digestion for absorption (bioaccessibility: 49-82%), kombu being the seaweed with the highest bioaccessibility. The incorporation of dialysis cell cultures to elucidate bioavailability modifies the estimation of the amount of iodine that may reach the systemic circulation (dialysis, 5-28%; cell culture, ≤3%). The paper discusses advantages and drawbacks of these methodologies for iodine bioavailability in seaweed.

  5. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

    Liang Xianwei; Zhu Shuzhen; Chen Peng; Zhu Lingyan

    2010-01-01

    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 ow s. The biota soil accumulation factors of PBDEs also declined with logK 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 ow s.

  7. 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.

  8. 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

  9. Aggregation, sedimentation, dissolution and bioavailability of ...

    Science.gov (United States)

    To understand their fate and transport in estuarine systems, the aggregation, sedimentation, and dissolution of CdSe quantum dots (QDs) in seawater were investigated. Hydrodynamic size increased from 40 to 60 nm to >1 mm within 1 h in seawater, and the aggregates were highly polydispersed. Their sedimentation rates in seawater were measured to be 4–10 mm/day. Humic acid (HA), further increased their size and polydispersity, and slowed sedimentation. Light increased their dissolution and release of dissolved Cd. The ZnS shell also slowed release of Cd ions. With sufficient light, HA increased the dissolution of QDs, while with low light, HA alone did not change their dissolution. The benthic zone in estuarine systems is the most probable long-term destination of QDs due to aggregation and sedimentation. The bioavailability of was evaluated using the mysid Americamysis bahia. The 7-day LC50s of particulate and dissolved QDs were 290 and 23 μg (total Cd)/L, respectively. For mysids, the acute toxicity appears to be from Cd ions; however, research on the effects of QDs should be conducted with other organisms where QDs may be lodged in critical tissues such as gills or filtering apparatus and Cd ions may be released and delivered directly to those tissues. Because of their increasing use and value to society, cadmium-based quantum dots (QDs) will inevitably find their way into marine systems. In an effort to understand the fate and transport of CdSe QDs in estuar

  10. Selenium bioavailability of infant milk diets

    International Nuclear Information System (INIS)

    Raghib, H.; Chan, W.Y.; Rennert, O.M.

    1986-01-01

    The effects of age, types of milk diet and chemical forms of SE on its bioavailability were studied using suckling rats as a model. Human milk, bovine milk and infant formula (regular Similac) extrinsically labeled with either ( 75 Se) selenite or ( 75 Se) selenomethionine were fed by gastric intubation to 8, 10, 15 and 20 (or 30)-day-old rats. Retention of 75 Se in gut free carcass and liver was measured 3 hours after feeding. At any given age the corresponding absorption of 75 Se from the 3 diets was similar except at 15 days of age when significantly more ( 75 Se) selenomethionine was absorbed from human milk (83%) than from bovine milk or formula (72%). Much higher amount of ( 75 Se) selenomethionine was absorbed by any age group from the 3 milk diets compared to ( 75 Se) selenite. An age related change in both ( 75 Se) selenite and ( 75 Se) selenomethionine absorption was noticed in all 3 diets. Gut free carcass ( 75 Se) selenite absorption was 32% in 8-d-old rats and increased to 46% in 20-d-old rats. The corresponding liver 75 Se retention was 7.5 and 19.5%. On the other hand, ( 75 Se) selenomethionine retention by the gut free carcass decreased with age from an average of 83% in 8-d-old rats to 72% in 20-d-old rats. The corresponding 75 Se incorporation into the liver increased from 15.5% in 8-d-old rats to 21.9% in 20-d-old rats. It is concluded that twice as much 75 Se) selenite and an age related change in 75 Se absorption was noticed between the 2 chemical forms of Se and between human milk and the other 2 milk diets

  11. Comparative bioavailability of two formulations of sibutramine.

    Science.gov (United States)

    Franco Spínola, A C; Almeida, S; Filipe, A; Neves, R; Abolfathi, Z; Yritia, M; Anctil, D

    2009-10-01

    This study was conducted in order to compare the bioavailability of two capsule formulations containing 15 mg of sibutramine, N-{1-[1-(4-chlorophenyl)cyclobutyl]-3-methylbutyl}-N,N-dimethylamine hydrochloride monohydrate, 84485-00-7 CAS registry number. 62 healthy subjects were enrolled in a single-center, randomized, single-dose, open-label, 2-way crossover study, with a minimum washout period of 14 days. Plasma samples were collected up to 72.0 hours post-dosing. R-sibutramine, S-sibutramine, N-mono-desmethyl-sibutramine (M1) and N-di-desmethyl-sibutramine (M2) levels were determined by reverse liquid chromatography and detected by tandem mass spectrometry detection, LC/MS/MS method. Pharmacokinetic parameters used for bioequivalence assessment were the area under the concentration-time curve from time zero to time of last non-zero concentration (AUC0-t) and the maximum observed concentration (Cmax). These parameters were determined from sibutramine enantiomers as well from M1 and M2 concentration data using non-compartmental analysis. The 90% confidence intervals obtained by analysis of variance were 89.25 - 122.88% for Cmax, 90.37 - 123.18% for AUC0-t and 91.20 - 122.38% for AUCinf for R-sibutramine and 88.27 - 124.08% for Cmax, 86.15 - 121.78% for AUC0-t and 88.02 - 120.96% for AUCinf for S-sibutramine. These results were all within the range of 80.00 - 125.00% established by regulatory requirements. Bioequivalence between formulations was concluded both in terms of rate and extent of absorption.

  12. Speciation and bioavailability of lead in complementary medicines

    International Nuclear Information System (INIS)

    Bolan, S.; Naidu, R.; Kunhikrishnan, A.; Seshadri, B.; Ok, Y.S.; Palanisami, T.; Dong, M.; Clark, I.

    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

  13. Bacterial metal resistance genes and metal bioavailability in contaminated sediments

    International Nuclear Information System (INIS)

    Roosa, Stéphanie; Wattiez, Ruddy; Prygiel, Emilie; Lesven, Ludovic; Billon, Gabriel; Gillan, David C.

    2014-01-01

    In bacteria a metal may be defined as bioavailable if it crosses the cytoplasmic membrane to reach the cytoplasm. Once inside the cell, specific metal resistance systems may be triggered. In this research, specific metal resistance genes were used to estimate metal bioavailability in sediment microbial communities. Gene levels were measured by quantitative PCR and correlated to metals in sediments using five different protocols to estimate dissolved, particle-adsorbed and occluded metals. The best correlations were obtained with czcA (a Cd/Zn/Co efflux pump) and Cd/Zn adsorbed or occluded in particles. Only adsorbed Co was correlated to czcA levels. We concluded that the measurement of czcA gene levels by quantitative PCR is a promising tool which may complement the classical approaches used to estimate Cd/Zn/Co bioavailability in sediment compartments. - Highlights: • Metal resistance genes were used to estimate metal bioavailability in sediments. • Gene levels were correlated to metals using 5 different metal extraction protocols. • CzcA gene levels determined by quantitative PCR is a promising tool for Cd/Zn/Co. - Capsule Bacterial czcA is a potential biomarker of Cd, Zn and Co bioavailability in aquatic sediments as shown by quantitative PCR and sequential metal extraction

  14. Bioaccessibility and bioavailability of phenolic compounds in bread: a review.

    Science.gov (United States)

    Angelino, Donato; Cossu, Marta; Marti, Alessandra; Zanoletti, Miriam; Chiavaroli, Laura; Brighenti, Furio; Del Rio, Daniele; Martini, Daniela

    2017-07-19

    Cereal-based products, like breads, are a vehicle for bioactive compounds, including polyphenols. The health effects of polyphenols like phenolic acids (PAs) are dependent on their bioaccessibility and bioavailability. The present review summarizes the current understanding of potential strategies to improve phenolic bioaccessibility and bioavailability and the main findings of in vitro and in vivo studies investigating these strategies applied to breads, including the use of raw ingredients with greater phenolic content and different pre-processing technologies, such as fermentation and enzymatic treatment of ingredients. There is considerable variability between in vitro studies, mainly resulting from the use of different methodologies, highlighting the need for standardization. Of the few in vivo bioavailability studies identified, acute, single-dose studies demonstrate that modifications to selected raw materials and bioprocessing of bran could increase the bioavailability, but not necessarily the net content, of bread phenolics. The two medium-term identified dietary interventions also demonstrated greater phenolic content, resulting from the modification of the raw materials used. Overall, the findings suggest that several strategies can be used to develop new bread products with greater phenolic bioaccessibility and bioavailability. However, due to the large variability and the few studies available, further investigations are required to determine better the usefulness of these innovative processes.

  15. Assessing the bioavailability and bioaccessibility of metals and metalloids.

    Science.gov (United States)

    Ng, Jack C; Juhasz, Albert; Smith, Euan; Naidu, Ravi

    2015-06-01

    Bioavailability (BA) determines the potential harm of a contaminant that exerts on the receptor. However, environmental guidelines for site contamination assessment are often set assuming the contaminant is 100 % bioavailable. This conservative approach to assessing site risk may result in the unnecessary and expensive remediation of a contaminated site. The National Environmental Protection Measures in Australia has undergone a statutory 5-year review that recommended that contaminant bioavailability and bioaccessibility (BAC) measures be adopted as part of the contaminated site risk assessment process by the National Environment Protection Council. We undertook a critical review of the current bioavailability and bioaccessibility approaches, methods and their respective limitations. The 'gold' standard to estimate the portion of a contaminant that reaches the system circulatory system (BA) of its receptor is to determine BA in an in vivo system. Various animal models have been utilised for this purpose. Because of animal ethics issues, and the expenses associated with performing in vivo studies, several in vitro methods have been developed to determine BAC as a surrogate model for the estimation of BA. However, few in vitro BAC studies have been calibrated against a reliable animal model, such as immature swine. In this review, we have identified suitable methods for assessing arsenic and lead BAC and proposed a decision tree for the determination of contaminant bioavailability and bioaccessibility for health risk assessment.

  16. The bioavailability of Chernobyl accident products

    International Nuclear Information System (INIS)

    Lujaniene, G.; Lujans, V.

    1995-01-01

    Full text: Following the Chernobyl NPP accident a great quantity of radionuclides was emitted to the atmosphere. A diverse fallout of radioactive pollutants to the earth's surface was conditioned by various factors. And this is testified by the distinctions in radionuclide composition and physicochemical forms of their carriers were measured in different regions. The study of physicochemical properties of radionuclides is necessary for the evaluation of their biological availability and for understanding and predicting their behavior in the environment. The physicochemical forms of radioactive nuclide carriers collected on April 28-20 and May 9-10 were investigated. In those samples the water soluble fractions of 137 Cs and 90 Sr carriers were 9 and 30%, respectively. The main part of these nuclides was bound to the exchangeable fraction of the carriers. For 137 Cs marked concentrations were provided by the from bound to organic (13%) and acid-soluble (12%) substances and for 90 Sr a considerable amount consisted of the organic (14%) and the fixed in crystal lattice (13%) forms. The investigation of the state of water soluble 137 Cs and 90 Sr shows that nuclides completely were of the cationic form. The dialysable fractions of both nuclides were about 90%. The bioavailability of 137 Cs and 90 Sr was about 60-70%. The fraction of water-soluble increased after the breakdown reactor was covered by an inert material. The radionuclide carrier properties greatly depend on the type of source and under the influence of various factors the radionuclide physicochemical forms are able to change and at the same time their biological availability changes as well. The influence of the source nature is confirmed by the analysis of aerosol samples brought to Lithuania following dust storms in Ukraine, where 94% of 134,137 Cs was observed in the residue, i. e. nuclide was bound to particles with penetration into crystal lattice. And also, following forest and peat-bog fires in

  17. 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

  18. 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.

  19. Bioavailability of lead in rats fed human diets

    International Nuclear Information System (INIS)

    Kostial, K.; Kello, D.

    1979-01-01

    The bioavailability of lead was studied in rats fed various baby foods (Babymix-turkey, Babymix-vegetables, Frutolino-fruit, Frutamix-bananas, Babyron-S-26, Truefood), cow's milk, bread, liver and standard rat diet. Lead absorption was determined by measuring the whole body retention of 203 Pb 6 days after a single oral application. Highest absorption values ranging from 17 to 20% were obtained in animals fed cow's milk and fruit foods. Rats on other human diets absorbed between 3 and 8% of the radioactive lead dose. Only in animals on rat diet lead absorption was below 1%. It is concluded that rats fed human diets show absorption values similar to those in humans. This might indicate that the bioavailability of lead is primarily dependent on dietary habits. This experimental model, if confirmed by further work, might be useful for obtaining preliminary data on the bioavailability of metals from various foods

  20. Pharmacokinetics and Bioavailability of Inhaled Esketamine in Healthy Volunteers.

    Science.gov (United States)

    Jonkman, Kelly; Duma, Andreas; Olofsen, Erik; Henthorn, Thomas; van Velzen, Monique; Mooren, René; Siebers, Liesbeth; van den Beukel, Jojanneke; Aarts, Leon; Niesters, Marieke; Dahan, Albert

    2017-10-01

    Esketamine is traditionally administered via intravenous or intramuscular routes. In this study we developed a pharmacokinetic model of inhalation of nebulized esketamine with special emphasis on pulmonary absorption and bioavailability. Three increasing doses of inhaled esketamine (dose escalation from 25 to 100 mg) were applied followed by a single intravenous dose (20 mg) in 19 healthy volunteers using a nebulizer system and arterial concentrations of esketamine and esnorketamine were obtained. A multicompartmental pharmacokinetic model was developed using population nonlinear mixed-effects analyses. The pharmacokinetic model consisted of three esketamine, two esnorketamine disposition and three metabolism compartments. The inhalation data were best described by adding two absorption pathways, an immediate and a slower pathway, with rate constant 0.05 ± 0.01 min (median ± SE of the estimate). The amount of esketamine inhaled was reduced due to dose-independent and dose-dependent reduced bioavailability. The former was 70% ± 5%, and the latter was described by a sigmoid EMAX model characterized by the plasma concentration at which absorption was impaired by 50% (406 ± 46 ng/ml). Over the concentration range tested, up to 50% of inhaled esketamine is lost due to the reduced dose-independent and dose-dependent bioavailability. We successfully modeled the inhalation of nebulized esketamine in healthy volunteers. Nebulized esketamine is inhaled with a substantial reduction in bioavailability. Although the reduction in dose-independent bioavailability is best explained by retention of drug and particle exhalation, the reduction in dose-dependent bioavailability is probably due to sedation-related loss of drug into the air.

  1. A Review of Mercury Bioavailability in Humans and Fish

    Directory of Open Access Journals (Sweden)

    Mark A. Bradley

    2017-02-01

    Full Text Available 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.

  2. 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.

  3. 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...

  4. Bioavailability of four oral Coenzyme Q formulations in healthy volunteers

    DEFF Research Database (Denmark)

    Weis, M.; Mortensen, S.A.; Rassing, M.R.

    1994-01-01

    The bioavailability of four different Coenzyme Q (CoQ) formulations was compared in ten healthy volunteers in a four-way randomised cross-over trial. The included formulations were: A hard gelatine capsule containing 100 mg of CoQ and 400 mg of Emcompress. Three soft gelatine capsules containing......Q (Bioquinon has the highest bioavailability. A difference in basic AUC and AUC after p.o.administration of CoQ was observed with respect to sex. A characteristic two peak-pattern was observed at the concentration-time profile....

  5. 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.

  6. 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

  7. Incorporating Contaminant Bioavailability into Sediment Quality Assessment Frameworks

    Science.gov (United States)

    The recently adopted sediment quality assessment framework for evaluating bay and estuarine sediments in the State of California incorporates bulk sediment chemistry as a key line of evidence(LOE) but does not address the bioavailability of measured contaminants. Thus, the chemis...

  8. Improved oral bioavailability of probucol by dry media-milling.

    Science.gov (United States)

    Li, Jia; Yang, Yan; Zhao, Meihui; Xu, Hui; Ma, Junyuan; Wang, Shaoning

    2017-09-01

    The polymer/probucol co-milled mixtures were prepared to improve drug dissolution rate and oral bioavailability. Probucol, a BCS II drug, was co-milled together with Copovidone (Kollidon VA64, VA64), Soluplus, or MCC using the dry media-milling process with planetary ball-milling equipment. The properties of the milled mixtures including morphology, crystal form, vitro drug dissolution and in vivo oral bioavailability in rats were evaluated. Probucol existed as an amorphous in the matrix of the co-milled mixtures containing VA64, which helped to enhance drug dissolution. The ternary mixture composed of VA64, RH40, and probucol showed increased dissolution rates in both sink and non-sink conditions. It also had a higher oral bioavailability compared to the reference formulation. Dry-media milling of binary or ternary mixtures composed of drug, polymer and surfactant possibly have wide applications to improve dissolution rate and oral bioavailability of water-insoluble drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Mobility, bioavailability, and toxic effects of cadmium in soil samples

    International Nuclear Information System (INIS)

    Prokop, Z.; Cupr, P.; Zlevorova-Zlamalikova V.; Komarek, J.; Dusek, L.; Holoubek, I.

    2003-01-01

    Total concentration is not a reliable indicator of metal mobility or bioavailability in soils. The physicochemical form determines the behavior of metals in soils and hence the toxicity toward terrestrial biota. The main objectives of this study were the application and comparison of three approaches for the evaluation of cadmium behavior in soil samples. The mobility and bioavailability of cadmium in five selected soil samples were evaluated using equilibrium speciation (Windermere humic aqueous mode (WHAM)), extraction procedures (Milli-Q water, DMSO, and DTPA), and a number of bioassays (Microtox, growth inhibition test, contact toxicity test, and respiration). The mobility, represented by the water-extractable fraction corresponded well with the amount of cadmium in the soil solution, calculate using the WHAM (r 2 =0.96, P<0.001). The results of the ecotoxicologica evaluation, which represent the bioavailable fraction of cadmium, correlated well with DTPA extractability and also with the concentration of free cadmium ion, which is recognized as the most bioavailable metal form. The results of the WHAM as well as the results of extraction experiments showed a strong binding of cadmium to organic matter and a weak sorption of cadmium to clay minerals

  10. Dynamic speciation analysis and bioavailability of metals in aquatic systems

    NARCIS (Netherlands)

    Leeuwen, van H.P.; Town, R.M.; Buffle, J.; Cleven, R.F.M.J.; Davison, W.; Puy, J.; Riemsdijk, van W.H.; Sigg, L.

    2005-01-01

    Dynamic metal speciation analysis in aquatic ecosystems is emerging as a powerful basis for development of predictions of bioavailability and reliable risk assessment strategies. A given speciation sensor is characterized by an effective time scale or kinetic window that defines the measurable metal

  11. Prediction of Petroleum Hydrocarbon Bioavailability in Contaminated Soils and Sediments

    NARCIS (Netherlands)

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

    2001-01-01

    Recently, several laboratory methods have been developed for the prediction of contaminant bioavailability. So far, none of these methods has been extensively tested for petroleum hydrocarbons. In the present study we investigated solid-phase extraction and persulfate oxidation for the prediction of

  12. Bioavailability of metals-trace in sediments: a review

    International Nuclear Information System (INIS)

    Rodrigues, Rafaela E. de A.V.; Souza, Vivianne Lucia Bormann; Lima, Vanessa Lemos de; Hazin, Clovis Abrahao

    2014-01-01

    The chemical association of metals in sediments provides an indication of its release by physical, chemical and biological processes, with toxic effects under certain environmental conditions. Knowing about their chemical bonds in sediments, can recognize specific sources of pollution, and speciation of trace metals is important for bioavailability and toxicity to animals and plants. The accumulation of these particles in the sediment occur by the following mechanisms: a) adsorption to the finest particles; b) precipitating of the element in the form of compounds; c) co-precipitating of the element with iron and manganese oxides; d) complexation with organic matter; e) incorporation into the crystal lattice of minerals. Currently, five phases are considered when studying the bioavailability of trace elements in sediments: a) the exchangeable phase, MgCl 2 (causes saltiness change); b) leachable phase, (acetic acid causes pH change); c) reducible phase (hydroxylamine hydrochloride causes release of the bound metals linked to Fe and Mn oxides); d) oxidized phase, the peroxide hydrogen (cause the degradation of organic matter); e) the residual pseudo-phase, the aqua regia (cause release of metals associated to minerals). The first three phases are considered the most bioavailable. In the last two fractions, the metals are linked to sediment constituents and not bioavailable. The organic phase is relatively stable and the metal present therein are removed under oxidative conditions. Metals present in the pseudo-phase residual measure the degree of environmental pollution, since great amount of metals at this stage indicates a lower degree of pollution

  13. The efficacy of urine data in comparative bioavailability of proguanil ...

    African Journals Online (AJOL)

    The bioavailability of proguanil formulated as suppository, was compared to the tablet formulation in a bid to evaluate the utility of the suppository dosage form as means of administering proguanil in children and high-risk groups, such as sickle cell patients, who may not tolerate oral route of administration. The study was a ...

  14. Effect of antacids in didanosine tablet on bioavailability of isoniazid.

    OpenAIRE

    Gallicano, K; Sahai, J; Zaror-Behrens, G; Pakuts, A

    1994-01-01

    The antacids in two didanosine placebo tablets had no significant effect on the plasma pharmacokinetics of a single oral dose of 300 mg of isoniazid administered to 12 healthy volunteers. These results suggest that isoniazid bioavailability will be unaffected by the antacids in didanosine tablets when the two medications are administered simultaneously to human immunodeficiency virus-seropositive patients.

  15. Effect of antacids in didanosine tablet on bioavailability of isoniazid.

    Science.gov (United States)

    Gallicano, K; Sahai, J; Zaror-Behrens, G; Pakuts, A

    1994-04-01

    The antacids in two didanosine placebo tablets had no significant effect on the plasma pharmacokinetics of a single oral dose of 300 mg of isoniazid administered to 12 healthy volunteers. These results suggest that isoniazid bioavailability will be unaffected by the antacids in didanosine tablets when the two medications are administered simultaneously to human immunodeficiency virus-seropositive patients.

  16. 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

  17. USE OF PELLETED LETTUCE SEEDS IN BIOAVAILABILITY STUDIES

    Science.gov (United States)

    Lettuce (Latuca sativa L., cv. Buttercrunch) is one of the most common and sensitive test organisms, among plants, used in toxicology and bioavailability studies. Much of the available lettuce seeds in commercial channels are pelleted to allow for precision machine planting. Th...

  18. Bioavailability of folate from processed spinach in humans

    NARCIS (Netherlands)

    Castenmiller, J.J.M.; Poll, van de C.J.; West, C.E.; Brouwer, I.A.; Thomas, C.M.G.; Dusseldorp, van M.

    2000-01-01

    The effect of the food matrix and dietary fibre on the bioavailability of folate is not known. In a controlled, 3-week dietary intervention study, 28 men and 42 women were divided into six groups to receive either a control diet (n = 10), or the control diet plus 20 g/MJ per day (n = 12 per group)

  19. Induction of interleukin-6 by coal containing bioavailable iron is ...

    Indian Academy of Sciences (India)

    Coal mining causes health problems, such as pneumoconiosis. We have previously shown that prevalence of pneumoconiosis in workers from various coalmine regions positively correlates with levels of bioavailable iron (BAI) in the coals from that region. In the present study, the nature of reactive oxygen species formed ...

  20. Rumen microorganisms decrease bioavailability of inorganic selenium supplements

    Science.gov (United States)

    Despite the availaility 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 w...

  1. Bioavailability and stability of mercury sulfide in Armuchee (USA) soil

    International Nuclear Information System (INIS)

    Han, Fengxiang; Shiyab, Safwan; Su, Yi; Monts, David L.; Waggoner, Charles A.; Matta, Frank B.

    2007-01-01

    Because of the adverse effects of elemental mercury and mercury compounds upon human health, the U.S. Department of Energy (DOE) is engaged in an on-going effort to monitor and remediate mercury-contaminated DOE sites. In order to more cost effectively implement those extensive remediation efforts, it is necessary to obtain an improved understanding of the role that mercury and mercury compounds play in the ecosystem. We have conducted pilot scale experiments to study the bioavailability of mercury sulfide in an Armuchee (eastern US ) soil. The effects of plants and incubation time on chemical stability and bioavailability of HgS under simulated conditions of the ecosystem have been examined, as has the dynamics of the dissolution of mercury sulfide by various extractants. The results show that mercury sulfide in contaminated Armuchee soil was still to some extent bioavailable to plants. After planting, soil mercury sulfide is more easily dissolved by both 4 M and 12 M nitric acid than pure mercury sulfide reagent. Dissolution kinetics of soil mercury sulfide and pure chemical reagent by nitric acid are different. Mercury release by EDTA from HgS-contaminated soil increased with time of reaction and soil mercury level. Chelating chemicals increase the solubility and bioavailability of mercury in HgS-contaminated soil. (authors)

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

    International Nuclear Information System (INIS)

    Straalen, N.M. van; Donker, M.H.; Vijver, M.G.; Gestel, C.A.M. van

    2005-01-01

    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 50 for the effect on body growth was rather constant and reproducible, while the internal EC 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 μg/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. 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.

  4. In vitro evaluation of dietary compounds to reduce mercury bioavailability.

    Science.gov (United States)

    Jadán-Piedra, Carlos; Vélez, Dinoraz; Devesa, Vicenta

    2018-05-15

    Mercury in foods, in inorganic form [Hg(II)] or as methylmercury (CH 3 Hg), can have adverse effects. Its elimination from foods is not technologically viable. To reduce human exposure, possible alternatives might be based on reducing its intestinal absorption. This study evaluates the ability of 23 dietary components to reduce the amount of mercury that is absorbed and reaches the bloodstream (bioavailability). We determined their effect on uptake of mercury in Caco-2 cells, a model of intestinal epithelium, exposed to Hg(II) and CH 3 Hg standards and to swordfish bioaccessible fractions. Cysteine, homocysteine, glutathione, quercetin, albumin and tannic reduce bioavailability of both mercury species. Fe(II), lipoic acid, pectin, epigallocatechin and thiamine are also effective for Hg(II). Some of these strategies also reduce Hg bioavailability in swordfish (glutathione, cysteine, homocysteine). Moreover, extracts and supplements rich in these compounds are also effective. This knowledge may help to define dietary strategies to reduce in vivo mercury bioavailability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Speciation and bioavailability of copper in Lake Tjeukemeer

    NARCIS (Netherlands)

    Verweij, W.

    1991-01-01

    Chapter 1: introduction

    In 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

  6. 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...

  7. Effect of dose increase or cimetidine co-administration on albendazole bioavailability

    NARCIS (Netherlands)

    Schipper, H. G.; Koopmans, R. P.; Nagy, J.; Butter, J. J.; Kager, P. A.; van Boxtel, C. J.

    2000-01-01

    The low bioavailability of albendazole affects the therapeutic response in patients with echinococcosis. Cimetidine co-administration is reported to improve bioavailability. To analyze the assumed dose-dependent bioavailability of albendazole, we administered 5 to 30 mg/kg albendazole to 6 male

  8. 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

  9. Origins and bioavailability of dissolved organic matter in groundwater

    Science.gov (United States)

    Shen, Yuan; Chapelle, Francis H.; Strom, Eric W.; Benner, Ronald

    2015-01-01

    Dissolved organic matter (DOM) in groundwater influences water quality and fuels microbial metabolism, but its origins, bioavailability and chemical composition are poorly understood. The origins and concentrations of dissolved organic carbon (DOC) and bioavailable DOM were monitored during a long-term (2-year) study of groundwater in a fractured-rock aquifer in the Carolina slate belt. Surface precipitation was significantly correlated with groundwater concentrations of DOC, bioavailable DOM and chromophoric DOM, indicating strong hydrological connections between surface and ground waters. The physicochemical and biological processes shaping the concentrations and compositions of DOM during its passage through the soil column to the saturated zone are conceptualized in the regional chromatography model. The model provides a framework for linking hydrology with the processes affecting the transformation, remineralization and microbial production of DOM during passage through the soil column. Lignin-derived phenols were relatively depleted in groundwater DOM indicating substantial removal in the unsaturated zone, and optical properties of chromophoric DOM indicated lower molecular weight DOM in groundwater relative to surface water. The prevalence of glycine, γ-aminobutyric acid, and d-enantiomers of amino acids indicated the DOM was highly diagenetically altered. Bioassay experiments were used to establish DOC-normalized yields of amino acids as molecular indicators of DOM bioavailability in groundwater. A relatively small fraction (8 ± 4 %) of DOC in groundwater was bioavailable. The relatively high yields of specific d-enantiomers of amino acids indicated a substantial fraction (15–34 %) of groundwater DOC was of bacterial origin.

  10. Bioavailability and Pharmacodynamics of Promethazine in Human Subjects

    Science.gov (United States)

    Putcha, Lakshmi; Flynn, Chris; Paloski, W. H. (Technical Monitor)

    2000-01-01

    Space Motion Sickness (SMS) is often treated in space with promethazine (PMZ). Anecdotal reports indicate that the common side effects of drowsiness and decrements in cognitive performance that are associated with PMZ administration (50 mg IM on the ground, are absent or less pronounced in space suggesting I that-the bioavailability and/or pharmacodynamic behavior of PMZ may be altered during space flight. There are limited flight opportunities available for clinical research in space, the NRA-99, therefore, solicits research required to improve, or answer specific questions about in-flight diagnosis, therapy, and post-flight rehabilitation. We propose here, to establish a noninvasive method for pharmacodynamic and therapeutic assessment of PMZ. The specific objectives of the proposed research are to, 1. Establish a saliva to plasma ratio of PMZ after administration, 2. Estimate the relative bioavailability of the three flight-specific dosage forms of PMZ, and 3. Establish the dose-response relationship of PMZ. We will estimate the bioavailability of intramuscular injection (IM), oral tablets and rectal suppositories in normal subjects during ambulatory and antiorthostatic; bed rest (ABR) conditions using novel stable isotope techniques. Drowsiness, cognitive performance and salivary flow rate will be measured as a function of circulating drug concentrations after administration of three IM doses of PMZ. We will compare and contrast the bioavailability of PMZ during normal and ABR conditions to examine whether or not ABR can simulate changes in drug, absorption and availability similar to those anticipated in a microgravity environment. Results of this study will validate methods for an approved study with this medication awaiting a flight opportunity for manifestation. These data will also provide the much needed information on the dynamics and therapeutic index. of this medication and their implications on crew fatigue and performance in space. Key words

  11. Phase behavior and oral bioavailability of amorphous Curcumin.

    Science.gov (United States)

    Pawar, Yogesh B; Shete, Ganesh; Popat, Dharmesh; Bansal, Arvind K

    2012-08-30

    Amorphous form has been used as a means to improve aqueous solubility and oral bioavailability of poorly water soluble drugs. The objective of present study was to characterize thermodynamic and kinetic parameters of amorphous form of Curcumin (CRM-A). CRM-A was found to be a good glass former with glass transition temperature (T(g)) of 342.64K and critical cooling rate below 1K/min. CRM-A had a moderate tendency of crystallization and exhibited Kauzmann temperature (T(KS)) of 294.23 K. CRM-A was found to be fragile in nature as determined by T(m)/T(g) (1.32), C(p)(1 iq):C(p)(glass) (1.22), strength parameter (D75), T(K)/T(g) (0.85), and T(g)-T(K) (48.41). Theoretically predicted aqueous solubility advantage of 43.15-folds, was reduced to 17-folds under practical conditions. This reduction in solubility was attributed to water induced devitrification, as evident through PXRD and SEM analysis. Further, oral bioavailability study of CRM-A was undertaken to investigate bioavailability benefits, if any. C(max) was improved by 1.97-folds (statistically significant difference over control). However, oral bioavailability (AUC(0-)(∞)) was improved by 1.45-folds (statistically non significant difference over control). These observations pointed towards role of rapid devitrification of CRM-A in GIT milieu, thus limiting its oral bioavailability advantage. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Systems biological approach of molecular descriptors connectivity: optimal descriptors for oral bioavailability prediction.

    Science.gov (United States)

    Ahmed, Shiek S S J; Ramakrishnan, V

    2012-01-01

    Poor oral bioavailability is an important parameter accounting for the failure of the drug candidates. Approximately, 50% of developing drugs fail because of unfavorable oral bioavailability. In silico prediction of oral bioavailability (%F) based on physiochemical properties are highly needed. Although many computational models have been developed to predict oral bioavailability, their accuracy remains low with a significant number of false positives. In this study, we present an oral bioavailability model based on systems biological approach, using a machine learning algorithm coupled with an optimal discriminative set of physiochemical properties. The models were developed based on computationally derived 247 physicochemical descriptors from 2279 molecules, among which 969, 605 and 705 molecules were corresponds to oral bioavailability, intestinal absorption (HIA) and caco-2 permeability data set, respectively. The partial least squares discriminate analysis showed 49 descriptors of HIA and 50 descriptors of caco-2 are the major contributing descriptors in classifying into groups. Of these descriptors, 47 descriptors were commonly associated to HIA and caco-2, which suggests to play a vital role in classifying oral bioavailability. To determine the best machine learning algorithm, 21 classifiers were compared using a bioavailability data set of 969 molecules with 47 descriptors. Each molecule in the data set was represented by a set of 47 physiochemical properties with the functional relevance labeled as (+bioavailability/-bioavailability) to indicate good-bioavailability/poor-bioavailability molecules. The best-performing algorithm was the logistic algorithm. The correlation based feature selection (CFS) algorithm was implemented, which confirms that these 47 descriptors are the fundamental descriptors for oral bioavailability prediction. The logistic algorithm with 47 selected descriptors correctly predicted the oral bioavailability, with a predictive accuracy

  13. Acetylated Hyaluronic Acid: Enhanced Bioavailability and Biological Studies

    Directory of Open Access Journals (Sweden)

    Carmela Saturnino

    2014-01-01

    Full Text Available Hyaluronic acid (HA, a macropolysaccharidic component of the extracellular matrix, is common to most species and it is found in many sites of the human body, including skin and soft tissue. Not only does HA play a variety of roles in physiologic and in pathologic events, but it also has been extensively employed in cosmetic and skin-care products as drug delivery agent or for several biomedical applications. The most important limitations of HA are due to its short half-life and quick degradation in vivo and its consequently poor bioavailability. In the aim to overcome these difficulties, HA is generally subjected to several chemical changes. In this paper we obtained an acetylated form of HA with increased bioavailability with respect to the HA free form. Furthermore, an improved radical scavenging and anti-inflammatory activity has been evidenced, respectively, on ABTS radical cation and murine monocyte/macrophage cell lines (J774.A1.

  14. Bioavailability in rats of metal adsorbed to soils

    International Nuclear Information System (INIS)

    Rubenstein, R.; Griffin, S.; Irene, S.; DeRosa, C.; Choudhury, H.

    1990-01-01

    The toxicity of metals to humans and animals has been well documented, however little data are available on the physiological bioavailability of metals from various soil types. These studies were designed to assess the bioavailability of sodium 75 selenate (NaS), 63 nickel chloride (NiCl) and 109 cadmium chloride (CdCl) adsorbed to sand or clay loam in rats. Each test compound was administered in seven dose groups: Group 1 - intravenously, Group 2 and 3 - oral aqueous solution by gavage, Groups 4-7 - aqueous suspension adsorbed to each soil type by gavage. Blood was collected from the jugular vein at intervals up to 48 hours post dosing and analyzed for radio-activity. Both NiCl and CdCl were poorly adsorbed from the soils. Approximately 3% of the CdCl bound to sand and 1.5% of the NiCl bound to clay loam were absorbed into the bloodstream. Approximately 0.5% and 0.1% of the CdCl bound to sand and clay, respectively were absorbed. NaS was well absorbed following oral administration with approximately 85% of the compound bound to sand and 94% bound to clay being absorbed into the blood. Bioavailability of metals from soil appears to be primarily affected by the ionic state of the metal. Anions, such as selenium, are more mobile in an acid environment and may leach more readily from soil. Cations, such as Ni and Cd may bind to soil more tightly, thus soil type becomes a factor affecting bioavailability

  15. 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

  16. Bioavailability of trans-resveratrol from red wine in humans.

    Science.gov (United States)

    Vitaglione, Paola; Sforza, Stefano; Galaverna, Gianni; Ghidini, Cristiana; Caporaso, Nicola; Vescovi, Pier Paolo; Fogliano, Vincenzo; Marchelli, Rosangela

    2005-05-01

    Many in vitro studies demonstrated significant biological effects of trans-resveratrol. Thus, understanding the rate of intestinal absorption and metabolization in vivo of trans-resveratrol is the prerequisite to evaluate its potential health impact. Bioavailability studies mainly in animals or in humans using the pure compound at very high doses were performed. In this work, trans-resveratrol bioavailability from a moderate consumption of red wine in 25 healthy humans has been studied by three different experiments. The wine ingestion was associated to three different dietary approaches: fasting, a standard meal, a meal with high and low amount of lipids. Trans-resveratrol 3- and 4'-glucuronides were synthesized, purified, and characterized as pure standards. Bioavailability data were obtained by measuring the concentration of free, 3-glucuronide and 4'-glucuronide trans-resveratrol by high-performance liquid chromatography (HPLC), both with ultraviolet (UV) and mass spectrometry (MS) detection, in serum samples taken at different times after red wine administration. Free trans-resveratrol was found, in trace amounts, only in some serum samples collected 30 min after red wine ingestion while after longer times resveratrol glucuronides predominated. Trans-resveratrol bioavailability was shown to be independent from the meal or its lipid content. The finding in human serum of trans-resveratrol glucuronides, rather than the free form of the compound, with a high interindividual variability, raises some doubts about the health effects of dietary resveratrol consumption and suggests that the benefits associated to red wine consumption could be probably due to the whole antioxidant pool present in red wine.

  17. Bioavailability of two oral formulations of triazolam using radioreceptor assay

    Energy Technology Data Exchange (ETDEWEB)

    Lapka, R; Cepelakova, H; Rejholec, V; Franc, Z

    1986-04-01

    The radioreceptor assay (RRA) was used to quantitate plasma triazolam concentration in eight female volunteers following single 0.5 mg doses of two tablet formulations in a cross-over study. Bioavailability in terms of area under the plasma concentration versus time curve, maximum plasma concentration, time to maximum, and mean residence time was not statistically significantly different from one formulation to the other.

  18. Relative bioavailability, metabolism and tolerability of rectally administered oxcarbazepine suspension.

    Science.gov (United States)

    Clemens, Pamela L; Cloyd, James C; Kriel, Robert L; Remmel, Rory P

    2007-01-01

    Maintenance of effective drug concentrations is essential for adequate treatment of epilepsy. Some antiepileptic drugs can be successfully administered rectally when the oral route of administration is temporarily unavailable. Oxcarbazepine is a newer antiepileptic drug that is rapidly converted to a monohydroxy derivative, the active compound. This study aimed to characterise the bioavailability, metabolism and tolerability of rectally administered oxcarbazepine suspension using a randomised, crossover design in ten healthy volunteers. Two subjects received 300 mg doses of oxcarbazepine suspension via rectal and oral routes and eight received 450 mg doses. A washout period of at least 2 weeks elapsed between doses. The rectal dose was diluted 1:1 with water. Blood samples and urine were collected for 72 hours post-dose. Adverse effects were assessed at each blood collection time-point using a self-administered questionnaire. Plasma was assayed for oxcarbazepine and monohydroxy derivative; urine was assayed for monohydroxy derivative and monohydroxy derivative-glucuronide. Maximum plasma concentration (C(max)) and time to reach C(max) (t(max)) were obtained directly from the plasma concentration-time curves. The areas under the concentration-time curve (AUCs) were determined via non-compartmental analysis. Relative bioavailability was calculated and the C(max) and AUCs were compared using Wilcoxon signed-rank tests. Mean relative bioavailability calculated from plasma AUCs was 8.3% (SD 5.5%) for the monohydroxy derivative and 10.8% (SD 7.3%) for oxcarbazepine. Oxcarbazepine and monohydroxy derivative C(max) and AUC values were significantly lower following rectal administration (p effects were headache and fatigue with no discernible differences between routes. Monohydroxy derivative bioavailability following rectal administration of oxcarbazepine suspension is significantly lower than following oral administration, most likely because of poor oxcarbazepine water

  19. Antimalarial Bioavailability and Disposition of Artesunate in Acute Falciparum Malaria

    OpenAIRE

    Newton, Paul; Suputtamongkol, Yupin; Teja-Isavadharm, Paktiya; Pukrittayakamee, Sasithon; Navaratnam, V; Bates, Imelda; White, Nicholas

    2000-01-01

    The pharmacokinetic properties of oral and intravenous artesunate (2 mg/kg of body weight) were studied in 19 adult patients with acute uncomplicated Plasmodium falciparum malaria by using a randomized crossover design. A sensitive bioassay was used to measure the antimalarial activity in plasma which results from artesunate and its principal metabolite, dihydroartemisinin. The oral study was repeated with 15 patients during convalescence. The mean absolute oral bioavailability of the antimal...

  20. Bioavailability and Pharmacokinetics of Oral Cocaine in Humans.

    Science.gov (United States)

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

    2018-06-01

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

  1. Solubility and bioavailability of stabilized amorphous calcium carbonate.

    Science.gov (United States)

    Meiron, Oren E; Bar-David, Elad; Aflalo, Eliahu D; Shechter, Assaf; Stepensky, David; Berman, Amir; Sagi, Amir

    2011-02-01

    Since its role in the prevention of osteoporosis in humans was proven some 30 years ago, calcium bioavailability has been the subject of numerous scientific studies. Recent technology allowing the production of a stable amorphous calcium carbonate (ACC) now enables a bioavailability analysis of this unique form of calcium. This study thus compares the solubility and fractional absorption of ACC, ACC with chitosan (ACC-C), and crystalline calcium carbonate (CCC). Solubility was evaluated by dissolving these preparations in dilute phosphoric acid. The results demonstrated that both ACC and ACC-C are more soluble than CCC. Fractional absorption was evaluated by intrinsically labeling calcium carbonate preparations with (45)Ca, orally administrated to rats using gelatin capsules. Fractional absorption was determined by evaluating the percentage of the administrated radioactive dose per milliliter that was measured in the serum, calcium absorption in the femur, and whole-body retention over a 34-hour period. Calcium serum analysis revealed that calcium absorption from ACC and ACC-C preparations was up to 40% higher than from CCC, whereas retention of ACC and ACC-C was up to 26.5% higher than CCC. Absorbed calcium in the femurs of ACC-administrated rats was 30% higher than in CCC-treated animals, whereas 15% more calcium was absorbed following ACC-C treatment than following CCC treatment. This study demonstrates the enhanced solubility and bioavailability of ACC over CCC. The use of stable ACC as a highly bioavailable dietary source for calcium is proposed based on the findings of this study. Copyright © 2011 American Society for Bone and Mineral Research.

  2. In Vitro Bioavailability Study of an Antiviral Compound Enisamium Iodide

    OpenAIRE

    Eleonore Haltner-Ukomadu; Svitlana Gureyeva; Oleksii Burmaka; Andriy Goy; Lutz Mueller; Grygorii Kostyuk; Victor Margitich

    2018-01-01

    An investigation into the biopharmaceutics classification and a study of the in vitro bioavailability (permeability and solubility) of the antiviral compound enisamium iodide (4-(benzylcarbamoyl)-1-methylpyridinium iodide) were carried out. The solubility of enisamium iodide was determined in four different buffers. Apparent intestinal permeability (Papp) of enisamium iodide was assessed using human colon carcinoma (Caco-2) cells at three concentrations. The solubility of enisamium iodide in ...

  3. Stable isotope studies of nicotine kinetics and bioavailability

    International Nuclear Information System (INIS)

    Benowitz, N.L.; Jacob, P. III; Denaro, C.; Jenkins, R.

    1991-01-01

    The stable isotope-labeled compound 3',3'-dideuteronicotine was used to investigate the disposition kinetics of nicotine in smokers, the systemic absorption of nicotine from cigarette smoke, and the bioavailability of nicotine ingested as oral capsules. Blood levels of labeled nicotine could be measured for 9 hours after a 30-minute intravenous infusion. Analysis of disposition kinetics in 10 healthy men revealed a multiexponential decline after the end of an infusion, with an elimination half-life averaging 203 minutes. This half-life was longer than that previously reported, indicating the presence of a shallow elimination phase. Plasma clearance averaged 14.6 ml/min/kg. The average intake of nicotine per cigarette was 2.29 mg. A cigarette smoke-monitoring system that directly measured particulate matter in smoke was evaluated in these subjects. Total particulate matter, number of puffs on the cigarette, total puff volume, and time of puffing correlated with the intake of nicotine from smoking. The oral bioavailability of nicotine averaged 44%. This bioavailability is higher than expected based on the systemic clearance of nicotine and suggests that there may be significant extrahepatic metabolism of nicotine

  4. Bioavailability of phosphorus from composts and struvite in acid soils

    Directory of Open Access Journals (Sweden)

    Carmo Horta

    Full Text Available ABSTRACT The objective of this study was to assess the type and fractions of phosphorus (P forms in composts and struvite and how these P forms affect the bioavailability of P in the soil. P fertilization was performed with compost from sewage sludge (CSS, compost from poultry litter (CPL and struvite (SV and compared with single superphosphate (SSP. P forms were quantified through a sequential fractionation scheme. The first extraction was performed with H2O, the second with 0.5 M NaHCO3, the third with 0.1 M NaOH and the fourth with 1 M HCl. The release of P over time, after soil P fertilization, was assessed by incubating the fertilizers with a low-P acid soil. P bioavailability was assessed through a micro-pot experiment with the incubated soils in a growth chamber using rye plants (Secale cereale L.. Inorganic P forms in the first two fractions represented ~50% (composts, 32% (SV and 86% (SSP of the total P; and in the HCl fraction, ~40% (composts, 26% (SV and 13% (SSP of the total P. Despite the variability of the P form fractions in the composts and struvite, the P release and bioavailability were similar among the fertilized treatments. The acidic nature of the soil, which improve solubility of Ca-P forms, and the high efficiency of rye, which favors P uptake, were factors that contributed to these results.

  5. Influence of ageing on zinc bioavailability in soils

    Energy Technology Data Exchange (ETDEWEB)

    Lock, K.; Janssen, C.R

    2003-12-01

    Currently, soil quality criteria or soil risk assessments of metals are based on laboratory toxicity tests which are carried out in soils freshly spiked with metal salts. With these data, species sensitivity distributions are fitted, from which hazardous concentrations and predicted no effect concentrations are derived. However, due to long-term processes, called ageing, soil metal availability decreases with time. Here we show that pH is the most important parameter determining the effect of ageing on zinc partitioning in soils, with the effect of ageing becoming more important with increasing pH. Furthermore, zinc bioavailability, expressed as the internal zinc concentrations in red clover (Trifolium pratense) is closely related to pore water zinc concentration. In addition, there is a clear dose-response relationship between the survival of the earthworm Eisenia fetida and the calcium chloride-extracted zinc fraction. These results indicate that zinc partitioning can be used to predict zinc bioavailability to terrestrial organisms. However, the use of spiked soils in toxicity assays can result in an over-estimation of the effects of zinc, especially at a high pH. - Zn ageing is affected by pH, while Zn partitioning can be used to predict its bioavailability.

  6. Bioavailability and stability of erythromycin delayed release tablets.

    Science.gov (United States)

    Ogwal, S; Xide, T U

    2001-12-01

    Erythromycin is available as the free base, ethylsuccinate, estolate, stearate, gluceptate, and lactobionate derivatives. When given orally erythromycin and its derivatives except the estolate are inactivated to some extent by the gastric acid and poor absorption may result. To establish whether delayed release erythromycin tablets meet the bioequivalent requirement for the market. Sectrophotometric analysis was used to determine the dissolution percentage of the tablets in vitro. High performance liquid chromatography and IBM/XT microcomputer was used to determine the bioavailability and pharmacokinetic parameters in vivo. Dissolution percentage in thirty minutes reached 28.9% and in sixty minutes erythromycin was completely released. The parameters of the delayed release tablets were Tlag 2.3 hr, Tmax.4.5 hr, and Cmax 2.123 g/ml Ka 0.38048 hr(-1) T (1/2) 1.8 hr, V*C/F 49.721 AUC 12.9155. The relative bioavailability of erythromycin delayed release tablet to erythromycin capsules was 105.31% The content, appearance, and dissolution bioavailability of delayed release erythromycin tablets conforms to the United States pharmacopoeia standards. The tablets should be stored in a cool and dry place in airtight containers and the shelf life is temporarily assigned two years.

  7. Nanoemulsifying drug delivery system to improve the bioavailability of piroxicam.

    Science.gov (United States)

    Motawea, Amira; Borg, Thanaa; Tarshoby, Manal; Abd El-Gawad, Abd El-Gawad H

    2017-05-01

    The aim of this study is to develop and characterize self-nanoemulsifying drug delivery system (SNEDDS) of piroxicam in liquid and solid forms to improve its dissolution, absorption and therapeutic efficacy. The generation of liquid SNEDDS (L-SNEDDS) was composed of soybean or coconut oil/Tween 80/Transcutol HP (12/80/8%w/w) and it was selected as the optimized formulation based on the solubility study and pseudo-ternary phase diagram. Optimized L-SNEDDS and liquid supersaturatable SNEDDS (L-sSNEDDS) preparations were then adsorbed onto adsorbents and formulated as directly compressed tablets. The improved drug dissolution rate in the solid supersaturatable preparation (S-sSNEDDS) may be due to the formation of a nanoemulsion and the presence of drug in an amorphous state with hydrogen bond interaction between the drug and SNEDDS components. In vivo pharmacokinetic studies on eight healthy human volunteers showed a significant improvement in the oral bioavailability of piroxicam from S-sSNEDDS (F12) compared with both the pure drug (PP) and its commercial product (Feldene ® ) (commercial dosage form (CD)). The relative bioavailability of S-sSNEDDS (F12) relative to PP or CD was about 151.01 and 98.96%, respectively. The obtained results ratify that S-sSNEDDS is a promising drug delivery system to enhance the oral bioavailability of piroxicam.

  8. 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.

  9. 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.

  10. Topical bioavailability of diclofenac from locally-acting, dermatological formulations.

    Science.gov (United States)

    Cordery, S F; Pensado, A; Chiu, W S; Shehab, M Z; Bunge, A L; Delgado-Charro, M B; Guy, R H

    2017-08-30

    Assessment of the bioavailability of topically applied drugs designed to act within or beneath the skin is a challenging objective. A number of different, but potentially complementary, techniques are under evaluation. The objective of this work was to evaluate in vitro skin penetration and stratum corneum tape-stripping in vivo as tools with which to measure topical diclofenac bioavailability from three approved and commercialized products (two gels and one solution). Drug uptake into, and its subsequent clearance from, the stratum corneum of human volunteers was used to estimate the input rate of diclofenac into the viable skin layers. This flux was compared to that measured across excised porcine skin in conventional diffusion cells. Both techniques clearly demonstrated (a) the superiority in terms of drug delivery from the solution, and (b) that the two gels performed similarly. There was qualitative and, importantly, quantitative agreement between the in vitro and in vivo measurements of drug flux into and beyond the viable skin. Evidence is therefore presented to support an in vivo - in vitro correlation between methods to assess topical drug bioavailability. The potential value of the stratum corneum tape-stripping technique to quantify drug delivery into (epi)dermal and subcutaneous tissue beneath the barrier is demonstrated. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Bioavailability of mercury in East Fork Poplar Creek soils

    International Nuclear Information System (INIS)

    Barnett, M.O.; Turner, R.R.

    1995-05-01

    The initial risk assessment for the East Fork Poplar Creek (EFPC) floodplain in Oak Ridge, Tennessee, a superfund site heavily contaminated with mercury, was based upon a reference dose for mercuric chloride, a soluble mercury compound not expected to be present in the floodplain, which is frequently saturated with water. Previous investigations had suggested mercury in the EFPC floodplain was less soluble and therefore less bioavailable than mercuric chloride, possibly making the results of the risk assessment unduly conservative. A bioavailability study, designed to measure the amount of mercury available for absorption in a child's digestive tract, the most critical risk endpoint and pathway, was performed on twenty soils from the EFPC floodplain. The average percentage of mercury released during the study for the twenty soils was 5.3%, compared to 100% of the compound mercuric chloride subjected to the same conditions. Alteration of the procedure to test additional conditions possible during soil digestion did not appreciably alter the results. Therefore, use of a reference dose for mercuric chloride in the EFPC risk assessment without inclusion of a corresponding bioavailability factor may be unduly conservative

  12. 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.

  13. Recycled water sources influence the bioavailability of copper to earthworms.

    Science.gov (United States)

    Kunhikrishnan, Anitha; Bolan, Nanthi S; Naidu, Ravi; Kim, Won-Il

    2013-10-15

    Re-use of wastewaters can overcome shortfalls in irrigation demand and mitigate environmental pollution. However, in an untreated or partially treated state, these water sources can introduce inorganic contaminants, including heavy metals, to soils that are irrigated. In this study, earthworms (Eisenia fetida) have been used to determine copper (Cu) bioavailability in two contrasting soils irrigated with farm dairy, piggery and winery effluents. Soils spiked with varying levels of Cu (0-1,000 mg/kg) were subsequently irrigated with recycled waters and Milli-Q (MQ) water and Cu bioavailability to earthworms determined by mortality and avoidance tests. Earthworms clearly avoided high Cu soils and the effect was more pronounced in the absence than presence of recycled water irrigation. At the highest Cu concentration (1,000 mg/kg), worm mortality was 100% when irrigated with MQ-water; however, when irrigated with recycled waters, mortality decreased by 30%. Accumulation of Cu in earthworms was significantly less in the presence of recycled water and was dependent on CaCl2-extractable free Cu(2+) concentration in the soil. Here, it is evident that organic carbon in recycled waters was effective in decreasing the toxic effects of Cu on earthworms, indicating that the metal-organic complexes decreased Cu bioavailability to earthworms. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. 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,

  15. pH-dependent solubility and permeability profiles: A useful tool for prediction of oral bioavailability.

    Science.gov (United States)

    Sieger, P; Cui, Y; Scheuerer, S

    2017-07-15

    pH-dependent solubility - permeability profiles offer a simple way to predict bioavailability after oral application, if bioavailability is only solubility and permeability driven. Combining both pH-dependent solubility and pH-dependent permeability in one diagram provides a pH-window (=ΔpH sol-perm ) from which the conditions for optimal oral bioavailability can be taken. The size of this window is directly proportional to the observed oral bioavailability. A set of 21 compounds, with known absolute human oral bioavailability, was used to establish this correlation. Compounds with ΔpH sol-perm bioavailability (bioavailability typically by approximately 25%. For compounds where ΔpH sol-perm ≥3 but still showing poor bioavailability, most probably other pharmacokinetic aspects (e.g. high clearance), are limiting exposure. Interestingly, the location of this pH-window seems to have a negligible influence on the observed oral bioavailability. In scenarios, where the bioavailability is impaired by certain factors, like for example proton pump inhibitor co-medication or food intake, the exact position of this pH-window might be beneficial for understanding the root cause. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Organoclays reduce arsenic bioavailability and bioaccessibility in contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Binoy; Naidu, Ravi; Rahman, Mohammad Mahmudur; Megharaj, Mallavarapu; Xi, Yunfei [South Australia Univ., Mawson Lakes, SA (AU). Centre for Environmental Risk Assessment and Remediation (CERAR); South Australia Univ., Mawson Lakes, SA (AU). Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE)

    2012-05-15

    Purpose: Naturally occurring layer silicate clay minerals can be value added by modifying their surface properties to enhance their efficacy in the remediation of environmental contaminants. Silicate clay minerals modified by the introduction of organic molecules into the mineral structure are known as organoclays and show much promise for environmental remediation applications. The present study assesses the extent of decrease in bioavailable and bioaccessible arsenic (As) via enhanced adsorption by soil treated with organoclays. Materials and methods: Organoclays were prepared from hexadecyl trimethylammonium bromide (HDTMA) and Arquad {sup registered} 2HT-75 (Arquad) at surfactant loadings equivalent to twice the cation exchange capacity (CEC) of an Australian bentonite and characterised by X-ray diffraction (XRD). Batch experiments were conducted to evaluate the adsorption of arsenate onto the organoclays from aqueous solutions. Encouraged by these results, the organoclays were applied to As-spiked soils, at 10% and 20% (w/w) rates, to assess their capacity to stabilise soil As. After 1 month of incubation in the laboratory, bioavailable (1 mM Ca(NO{sub 3}){sub 2} extractable) and bioaccessible (1 M glycine extractable) As from the spiked soils were assessed. Results and discussion: Both the organobentonites effectively removed As from aqueous solutions. The adsorbent prepared with Arquad adsorbed 23% more As from aqueous phase than adsorbent prepared with HDTMA. Adsorption of As was controlled by anion exchange and electrostatic attraction. When applied to As-contaminated soils, the organoclays reduced the bioavailable As by as much as 81%. The extent of reduction of bioaccessible As was only up to 58%. The adsorbents were not as efficient in reducing bioaccessible As in contaminated soils as compared with bioavailable As. It could be attributed to the extreme pH condition (pH = 3) of the extractant used in the physiologically based extraction test method for

  17. Bioavailability of zinc and copper in biosolids compared to their soluble salts

    International Nuclear Information System (INIS)

    Heemsbergen, Diane A.; McLaughlin, Mike J.; Whatmuff, Mark; Warne, Michael St.J.; Broos, Kris; Bell, Mike; Nash, David; Barry, Glenn; Pritchard, Deb; Penney, Nancy

    2010-01-01

    For essential elements, such as copper (Cu) and zinc (Zn), the bioavailability in biosolids is important from a nutrient release and a potential contamination perspective. Most ecotoxicity studies are done using metal salts and it has been argued that the bioavailability of metals in biosolids can be different to that of metal salts. We compared the bioavailability of Cu and Zn in biosolids with those of metal salts in the same soils using twelve Australian field trials. Three different measures of bioavailability were assessed: soil solution extraction, CaCl 2 extractable fractions and plant uptake. The results showed that bioavailability for Zn was similar in biosolid and salt treatments. For Cu, the results were inconclusive due to strong Cu homeostasis in plants and dissolved organic matter interference in extractable measures. We therefore recommend using isotope dilution methods to assess differences in Cu availability between biosolid and salt treatments. - Metals in biosolids are not necessarily less bioavailable than their soluble salt.

  18. Research progress on berberine with a special focus on its oral bioavailability.

    Science.gov (United States)

    Liu, Chang-Shun; Zheng, Yu-Rong; Zhang, Ying-Feng; Long, Xiao-Ying

    2016-03-01

    The natural product berberine (BBR) has become a potential drug in the treatment of diabetes, hyperlipidemia, and cancer. However, the oral delivery of BBR is challenged by its poor bioavailability. It is necessary to improve the oral bioavailability of BBR before it can be used in many clinical applications. Understanding the pharmacokinetic characteristics of BBR will enable the development of suitable formulas that have improved oral bioavailability. The key considerations for BBR are how to enhance the drug absorption and to avoid the intestinal first-pass effect. This review summarizes the pharmacological activities of BBR and analyzes the factors that lead to its poor oral bioavailability. In particular, the therapeutic potential of BBR in new indications from the aspect of oral bioavailability is discussed. In conclusion, BBR is a promising drug candidate for metabolic disorders and cancer but faces considerable challenges due to its poor oral bioavailability. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Bioavailability of zinc and copper in biosolids compared to their soluble salts

    Energy Technology Data Exchange (ETDEWEB)

    Heemsbergen, Diane A., E-mail: diane.heemsbergen@csiro.a [Centre for Environmental Contaminants Research, CSIRO Land and Water, PMB 2, Glen Osmond, Adelaide, SA 5064 (Australia); McLaughlin, Mike J., E-mail: mike.mclaughlin@csiro.a [Centre for Environmental Contaminants Research, CSIRO Land and Water, PMB 2, Glen Osmond, Adelaide, SA 5064 (Australia); School of Earth and Environmental Sciences, University of Adelaide, Adelaide, SA 5064 (Australia); Whatmuff, Mark, E-mail: mark.whatmuff@csiro.a [Centre for Environmental Contaminants Research, CSIRO Land and Water, PMB 2, Glen Osmond, Adelaide, SA 5064 (Australia); NSW Department of Primary Industries, Locked Bag 4 Richmond, NSW 2753 (Australia); Warne, Michael St.J., E-mail: michael.warne@csiro.a [Centre for Environmental Contaminants Research, CSIRO Land and Water, PMB 2, Glen Osmond, Adelaide, SA 5064 (Australia); Broos, Kris, E-mail: kris.broos@vito.b [Centre for Environmental Contaminants Research, CSIRO Land and Water, PMB 2, Glen Osmond, Adelaide, SA 5064 (Australia); Bell, Mike, E-mail: Mike.Bell@dpi.qld.gov.a [Department of Primary Industries, Kingaroy, Queensland 4610 (Australia); Nash, David, E-mail: David.Nash@dpi.vic.gov.a [Department of Primary Industries, Ellinbank, Victoria 3821 (Australia); Barry, Glenn, E-mail: Glenn.Barry@nrw.qld.gov.a [Department of Natural Resources and Mines, Indooroopilly, Queensland 4068 (Australia); Pritchard, Deb, E-mail: D.Pritchard@curtin.edu.a [Curtin University of Technology, Muresk Institute, Northam, Western Australia 6401 (Australia); Penney, Nancy, E-mail: Nancy.Penney@WaterCorporation.com.a [Water Corporation of Western Australia, Leederville, Western Australia 6001 (Australia)

    2010-05-15

    For essential elements, such as copper (Cu) and zinc (Zn), the bioavailability in biosolids is important from a nutrient release and a potential contamination perspective. Most ecotoxicity studies are done using metal salts and it has been argued that the bioavailability of metals in biosolids can be different to that of metal salts. We compared the bioavailability of Cu and Zn in biosolids with those of metal salts in the same soils using twelve Australian field trials. Three different measures of bioavailability were assessed: soil solution extraction, CaCl{sub 2} extractable fractions and plant uptake. The results showed that bioavailability for Zn was similar in biosolid and salt treatments. For Cu, the results were inconclusive due to strong Cu homeostasis in plants and dissolved organic matter interference in extractable measures. We therefore recommend using isotope dilution methods to assess differences in Cu availability between biosolid and salt treatments. - Metals in biosolids are not necessarily less bioavailable than their soluble salt.

  20. 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.

  1. Bioavailability of isoflavones from soy products in equol producers and non-producers in Japanese women

    OpenAIRE

    Ayako Miura; Chitose Sugiyama; Hiroyuki Sakakibara; Kayoko Simoi; Toshinao Goda

    2016-01-01

    Background: The estimated intake of soy isoflavones from a meal has been based on the content in a food, but the health effects of soy isoflavones are possibly affected by their bioavailability. In this study we have evaluated the isoflavone bioavailability after the intake of three kinds of soy foods and a commercial soy isoflavone supplement, and examined whether the isoflavone bioavailability is different between equol producers and non-producers. Methods: Healthy female subjects (n = 2...

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

    International Nuclear Information System (INIS)

    Gomez-Eyles, Jose L.; Collins, Chris D.; Hodson, Mark E.

    2011-01-01

    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.

  3. Role of organic acids on the bioavailability of selenium in soil: A review.

    Science.gov (United States)

    Dinh, Quang Toan; Li, Zhe; Tran, Thi Anh Thu; Wang, Dan; Liang, Dongli

    2017-10-01

    Organic Acids (OAs) are important components in the rhizosphere soil and influence Se bioavailability in soil. OAs have a bidirectional contrasting effect on Se bioavailability. Understanding the interaction of OAs with Se is essential to assessing Se bioavailability in soil and clarifying the role of OAs in controlling the behavior and fate of Se in soil. This review examines the mechanisms for the (im)mobilization of Se by OAs and discusses the practical implications of these mechanisms in relation to sequestration and bioavailability of Se in soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. 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

  5. Sorption, transport and biodegradation - An insight into bioavailability of persistent organic pollutants in soil.

    Science.gov (United States)

    Ren, Xiaoya; Zeng, Guangming; Tang, Lin; Wang, Jingjing; Wan, Jia; Liu, Yani; Yu, Jiangfang; Yi, Huan; Ye, Shujing; Deng, Rui

    2018-01-01

    Contamination of soils with persistent organic pollutants (POPs), such as organochlorine pesticide, polybrominated diphenyl ethers, halohydrocarbon, polycyclic aromatic hydrocarbons (PAHs) is of increasing concern. Microbial degradation is potential mechanism for the removal of POPs, but it is often restricted by low bioavailability of POPs. Thus, it is important to enhance bioavailability of POPs in soil bioremediation. A series of reviews on bioavailability of POPs has been published in the past few years. However, bioavailability of POPs in relation to soil organic matter, minerals and soil microbes has been little studied. To fully understand POPs bioavailability in soil, research on interactions of POPs with soil components and microbial responses in bioavailability limitation conditions are needed. This review focuses on bioavailability mechanisms of POPs in terms of sorption, transport and microbial adaptation, which is particularly novel. In consideration of the significance of bioavailability, further studies should investigate the influence of various bioremediation strategies on POPs bioavailability. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. 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.

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

    Science.gov (United States)

    Chapelle, Francis H.; Bradley, Paul M.; Journey, Celeste A.; 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.

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

    Science.gov (United States)

    Chapelle, Francis H; Bradley, Paul M; Journey, Celeste A; 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. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

  9. Pharmacokinetics, bioavailability, tissue distribution and excretion of tangeretin in rat

    Directory of Open Access Journals (Sweden)

    Wei-Lun Hung

    2018-04-01

    Full Text Available Tangeretin, 4′,5,6,7,8-pentamethoxyflavone, is one of the major polymethoxyflavones (PMFs existing in citrus fruits, particularly in the peels of sweet oranges and mandarins. Tangeretin has been reported to possess several beneficial bioactivities including anti-inflammatory, anti-proliferative and neuroprotective effects. To achieve a thorough understanding of the biological actions of tangeretin in vivo, our current study is designed to investigate the pharmacokinetics, bioavailability, distribution and excretion of tangeretin in rats. After oral administration of 50 mg/kg bw tangeretin to rats, the Cmax, Tmax and t1/2 were 0.87 ± 0.33 μg/mL, 340.00 ± 48.99 min and 342.43 ± 71.27 min, respectively. Based on the area under the curves (AUC of oral and intravenous administration of tangeretin, calculated absolute oral bioavailability was 27.11%. During tissue distribution, maximum concentrations of tangeretin in the vital organs occurred at 4 or 8 h after oral administration. The highest accumulation of tangeretin was found in the kidney, lung and liver, followed by spleen and heart. In the gastrointestinal tract, maximum concentrations of tangeretin in the stomach and small intestine were found at 4 h, while in the cecum, colon and rectum, tangeretin reached the maximum concentrations at 12 h. Tangeretin excreted in the urine and feces was recovered within 48 h after oral administration, concentrations were only 0.0026% and 7.54%, respectively. These results suggest that tangeretin was mainly eliminated as metabolites. In conclusion, our study provides useful information regarding absorption, distribution, as well as excretion of tangeretin, which will provide a good base for studying the mechanism of its biological effects. Keywords: Tangeretin, Oral bioavailability, Pharmacokinetics, Tissue distribution, Excretion

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

    International Nuclear Information System (INIS)

    Tamponnet, C.; Martin-Garin, A.; Gonze, M.-A.; Parekh, N.; Vallejo, R.; Sauras-Yera, T.; Casadesus, J.; Plassard, C.; Staunton, S.; Norden, M.; Avila, R.; Shaw, G.

    2008-01-01

    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 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 its

  11. 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

  12. 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....

  13. Chemical and biological factors affecting bioavailability of contaminants in seawater

    International Nuclear Information System (INIS)

    Knezovich, J.P.

    1992-09-01

    This paper discusses the influence that salinity has on the bioavailability of the two largest classes of contaminants, trace metals and organic compounds will be discussed. Although data on contaminant toxicity will be used to draw inferences about chemical availability, this discussion will focus on the properties that contaminants are likely to exhibit in waters of varying salinities. In addition, information on physiological changes that are affected by salinity will be used to illustrate how biological effects can alter the apparent availability of contaminants

  14. The influence of dissolved phosphorus molecular form on recalcitrance and bioavailability

    International Nuclear Information System (INIS)

    Li, Bo; Brett, Michael T.

    2013-01-01

    Several studies have shown Soluble Reactive Phosphorus (SRP) analyses provide a poor index of dissolved phosphorus (P) bioavailability in natural systems. We tested 21 inorganic and organic P containing compounds with series of nutrient uptake and bioavailability bioassay experiments and chemical characterizations. Our results show that in 81% of cases, these compounds did not fit the classic assumption that SRP approximately equals Bioavailable P (BAP). Many organic compounds were classified as non-reactive, but had very rapid uptake kinetics and were nearly entirely bioavailable (e.g., several nucleic acids, ATP, RNA, DNA and phosphatidylcholine). Several inorganic compounds also classified as non-reactive but had high bioavailability (i.e., sodium tripolyphosphate and phosphorus pentoxide). Conversely, apatite was operationally classified as reactive, but had low bioavailability. Due to their tendency to alias as SRP, but recalcitrance and very low bioavailability, humic-(Al/Fe)-phosphorus complexes may play an especially important role in the dissolved phosphorus dynamics of natural systems. Highlights: •We tested 21 P containing compounds with bioassay and chemical speciation. •The acid molybdate method does not consistently predict the bioavailability of P compounds. •The P in humic substances was bounded with Al/Fe and could not be taken up by algal. •A new classification scheme divided P species based on bioavailability and chemical speciation. -- SRP is a poor indicator of the bioavailability of many of P containing compounds and much of what is classified as SRP in nature could be associated with humic-metal complexes with low bioavailability

  15. Polymeric Nanoparticles for Increasing Oral Bioavailability of Curcumin

    Directory of Open Access Journals (Sweden)

    Anita Umerska

    2018-03-01

    Full Text Available Despite the promising biological and antioxidant properties of curcumin, its medical applications are limited due to poor solubility in water and low bioavailability. Polymeric nanoparticles (NPs adapted to oral delivery may overcome these drawbacks. Properties such as particle size, zeta potential, morphology and encapsulation efficiency were assessed. Then, the possibility of storing these NPs in a solid-state form obtained by freeze-drying, in vitro curcumin dissolution and cytocompatibility towards intestinal cells were evaluated. Curcumin-loaded Eudragit® RLPO (ERL NPs showed smaller particle diameters (245 ± 2 nm and better redispersibility after freeze-drying than either poly(lactic-co-glycolic acid (PLGA or polycaprolactone (PCL NPs. The former NPs showed lower curcumin encapsulation efficiency (62% than either PLGA or PCL NPs (90% and 99%, respectively. Nevertheless, ERL NPs showed rapid curcumin release with 91 ± 5% released over 1 h. The three curcumin-loaded NPs proposed in this work were also compatible with intestinal cells. Overall, ERL NPs are the most promising vehicles for increasing the oral bioavailability of curcumin.

  16. 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.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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. - Highlights: • Polyethylene and polystyrene microplastics efficiently adsorbed pyrene. • Pyrene adsorbed on microplastics was readily bioavailable for mussels. • Microplastics affected several molecular and cellular pathways. • Potential toxicological risk can arise from virgin and contaminated microplastics. - Pyrene adsorbed on microplastics is accumulated in tissues of marine mussels. Transcriptional and cellular responses highlight the potential risk of virgin and contaminated polymers

  18. 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.

  19. Bioavailability of zinc from sweet potato roots and leaves

    International Nuclear Information System (INIS)

    Baiden, H.N.; Ercanli-Huffman, F.G.

    1986-01-01

    Bioavailability of zinc from sweet potato (SP) roots and leaves were determined, by extrinsic labeling technique, in rats fed control and zinc deficient diets. Weanling male Sprague Dawley (SD) rats (60-75g) were divided into 4 groups, and fed laboratory chow, a control diet (ad libitum and pair fed) and a zinc deficient diet, for 4 weeks. Each group then was divided into at least 2 sub groups, containing 6 rats, which were intubated with one of 3 tubing solutions extrinsically labeled with 65 Zn; baked sweet potato roots (BSPR), raw sweet potato leaves (RSPL) and cooked sweet potato leaves (CSPL). Five hours after intubation the rats were sacrificed, blood, liver, testes, spleen, heart, brain, thymus and lungs were removed. Feces, urine, and GI tract contents were collected and their 65 Zn activity was determined in a gamma counter. In all treatment groups zinc bioavailability from BSPR, RSPL or CSPL were not significantly different. Zinc deficient rats absorbed significantly more (P 65 Zn (86-90% of the dose), regardless of type of tubing solution than the pairfed or control animals (35-58% of the dose). The highest retention of 65 Zn was found in the liver (12-20% of absorbed dose), GI tract (6-17% of absorbed dose), kidney (2-8% of absorbed dose), and blood (1-5% of absorbed dose). The lowest retention was found in the brain, heart, thymus and testes. (< 1% of absorbed dose)

  20. 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.

  1. Measurement, analysis and prediction of topical UV filter bioavailability.

    Science.gov (United States)

    Roussel, L; Gilbert, E; Salmon, D; Serre, C; Gabard, B; Haftek, M; Maibach, H I; Pirot, F

    2015-01-30

    The aim of the present study was to objectively quantify and predict bioavailability of three sunscreen agents (i.e., benzophenone-3, 2-ethylhexylsalicylate, and 2 ethylhexyl-4-methoxycinnamate) in epidermis treated by petrolatum and emulsion-based formulations for 7 and 30min on four human volunteers. Profiles of sunscreen agents through stratum corneum (SC), derived from the assessment of chemical amounts in SC layers collected by successive adhesive tape-stripping, were successfully fitted to Fick's second law of diffusion. Therefore, permeability coefficients of sunscreen agents were found lower with petrolatum than with emulsion based formulations confirming the crucial role of vehicle in topical delivery. Furthermore, the robustness of that methodology was confirmed by the linear relationship between the chemical absorption measured after 30min and that predicted from the 7-min exposure experiment. Interestingly, in this dermatopharmacokinetic method, the deconvolution of permeability coefficients in their respective partition coefficients and absorption constants allowed a better understanding of vehicle effects upon topical bioavailability mechanisms and bioequivalence of skin products. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. 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.

  3. Amyloid fibril systems reduce, stabilize and deliver bioavailable nanosized iron

    Science.gov (United States)

    Shen, Yi; Posavec, Lidija; Bolisetty, Sreenath; Hilty, Florentine M.; Nyström, Gustav; Kohlbrecher, Joachim; Hilbe, Monika; Rossi, Antonella; Baumgartner, Jeannine; Zimmermann, Michael B.; Mezzenga, Raffaele

    2017-07-01

    Iron-deficiency anaemia (IDA) is a major global public health problem. A sustainable and cost-effective strategy to reduce IDA is iron fortification of foods, but the most bioavailable fortificants cause adverse organoleptic changes in foods. Iron nanoparticles are a promising solution in food matrices, although their tendency to oxidize and rapidly aggregate in solution severely limits their use in fortification. Amyloid fibrils are protein aggregates initially known for their association with neurodegenerative disorders, but recently described in the context of biological functions in living organisms and emerging as unique biomaterial building blocks. Here, we show an original application for these protein fibrils as efficient carriers for iron fortification. We use biodegradable amyloid fibrils from β-lactoglobulin, an inexpensive milk protein with natural reducing effects, as anti-oxidizing nanocarriers and colloidal stabilizers for iron nanoparticles. The resulting hybrid material forms a stable protein-iron colloidal dispersion that undergoes rapid dissolution and releases iron ions during acidic and enzymatic in vitro digestion. Importantly, this hybrid shows high in vivo iron bioavailability, equivalent to ferrous sulfate in haemoglobin-repletion and stable-isotope studies in rats, but with reduced organoleptic changes in foods. Feeding the rats with these hybrid materials did not result in abnormal iron accumulation in any organs, or changes in whole blood glutathione concentrations, inferring their primary safety. Therefore, these iron-amyloid fibril hybrids emerge as novel, highly effective delivery systems for iron in both solid and liquid matrices.

  4. Dissolution and oral bioavailability enhancement of praziquantel by solid dispersions.

    Science.gov (United States)

    Liu, Yanyan; Wang, Tianzi; Ding, Wenya; Dong, Chunliu; Wang, Xiaoting; Chen, Jianqing; Li, Yanhua

    2018-06-01

    The aim of the present investigation was to enhance the solubility, dissolution, and oral bioavailability of praziquantel (PZQ), a poorly water-soluble BCS II drug (Biopharmaceutical Classification System), using a solid dispersion (SD) technique involving hydrophilic copolymers. The SD formulations were prepared by a solvent evaporation method with PZQ and PEG 4000 (polyethylene glycol 4000), PEG 6000, or P 188 polymers at various weight ratios or a combination of PEG 4000/P 188. The optimized SD formulation, which had the highest solubility in distilled water, was further characterized by its surface morphology, crystallinity, and dissolution in 0.1 M HCl with 0.2% w/v of sodium dodecyl sulfate (SDS). X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed the amorphous form of PZQ in the SDs. Moreover, at an oral dosage of 5 mg/kg PZQ, the SDs had higher C max values and areas under the curve (AUCs) compared to those of commercial PZQ tablets. Preparation of PZQ-loaded SDs using PEG 4000/P 188 is a promising strategy to improve the oral bioavailability of PZQ.

  5. Role of Marine Snows in Microplastic Fate and Bioavailability.

    Science.gov (United States)

    Porter, Adam; Lyons, Brett P; Galloway, Tamara S; Lewis, Ceri

    2018-06-01

    Microplastics contaminate global oceans and are accumulating in sediments at levels thought sufficient to leave a permanent layer in the fossil record. Despite this, the processes that vertically transport buoyant polymers from surface waters to the benthos are poorly understood. Here we demonstrate that laboratory generated marine snows can transport microplastics of different shapes, sizes, and polymers away from the water surface and enhance their bioavailability to benthic organisms. Sinking rates of all tested microplastics increased when incorporated into snows, with large changes observed for the buoyant polymer polyethylene with an increase in sinking rate of 818 m day -1 and for denser polyamide fragments of 916 m day -1 . Incorporation into snows increased microplastic bioavailability for mussels, where uptake increased from zero to 340 microplastics individual -1 for free microplastics to up to 1.6 × 10 5 microplastics individual -1 when incorporated into snows. We therefore propose that marine snow formation and fate has the potential to play a key role in the biogeochemical processing of microplastic pollution.

  6. 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.

  7. In Vitro Bioavailability Study of an Antiviral Compound Enisamium Iodide

    Directory of Open Access Journals (Sweden)

    Eleonore Haltner-Ukomadu

    2018-01-01

    Full Text Available An investigation into the biopharmaceutics classification and a study of the in vitro bioavailability (permeability and solubility of the antiviral compound enisamium iodide (4-(benzylcarbamoyl-1-methylpyridinium iodide were carried out. The solubility of enisamium iodide was determined in four different buffers. Apparent intestinal permeability (Papp of enisamium iodide was assessed using human colon carcinoma (Caco-2 cells at three concentrations. The solubility of enisamium iodide in four buffer solutions from pH 1.2 to 7.5 is about 60 mg/mL at 25 °C, and ranges from 130 to 150 mg/mL at 37 °C, depending on the pH. Based on these results, enisamium iodide can be classified as highly soluble. Enisamium iodide demonstrated low permeability in Caco-2 experiments in all tested concentrations of 10–100 μM with permeability coefficients between 0.2 × 10−6 cm s−1 and 0.3 × 10−6 cm s−1. These results indicate that enisamium iodide belongs to class III of the Biopharmaceutics Classification System (BCS due to its high solubility and low permeability. The bioavailability of enisamium iodide needs to be confirmed in animal and human studies.

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

    International Nuclear Information System (INIS)

    Chakraborty, Parthasarathi; Ramteke, Darwin; Chakraborty, Sucharita

    2015-01-01

    Highlights: • Metal speciation controls bioavailability in mangrove ecosystem. • Bioavailability of Ni was controlled by Fe/Mn-oxyhydroxide and organic phases • Bioavailability of Cu in mangrove roots was controlled by organic phase in the sediments. • Cu interacts more strongly with organic phases than Ni in mangrove sediment. - Abstract: Sequential extraction study was performed to determine the concentrations of non-residual metal-complexes in the mangrove sediments from the Divar Island, (west coast of India). Accumulation of metal in the mangrove roots (from the same location) 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 mainly associated with Fe/Mn oxyhydroxide and organic phases in the sediments. A part of these metal fractions were bioavailable in the system. These two phases were the major controlling factors for Ni speciation and their bioavailability in the studied sediments. However, Cu was found to interact more strongly with the organic phases than Ni in the mangrove sediments. Organic phases in the mangrove sediments acted as buffer to control the speciation and bioavailability of Cu in the system

  9. Bioavailability of Isothiocyanates From Broccoli Sprouts in Protein, Lipid, and Fiber Gels

    NARCIS (Netherlands)

    Oliviero, Teresa; Lamers, Simone; Capuano, Edoardo; Dekker, Matthijs; Verkerk, Ruud

    2018-01-01

    Scope: Optimization of bioavailability of dietary bioactive health-beneficial compounds is as important as increasing their concentration in foods. The aim of this study is to explore the change in bioavailability of isothiocyanates (ITCs) in broccoli sprouts incorporated in protein, fiber, and

  10. 21 CFR 320.25 - Guidelines for the conduct of an in vivo bioavailability study.

    Science.gov (United States)

    2010-04-01

    ... conduct of an in vivo bioavailability study. (a) Guiding principles. (1) The basic principle in an in vivo... not been approved for marketing can be used to measure the following pharmacokinetic data: (i) The bioavailability of the formulation proposed for marketing; and (ii) The essential pharmacokinetic characteristics...

  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

  12. 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 pharmacological effect or clinical evidence. 320.28 Section 320.28 Food and Drugs FOOD AND DRUG ADMINISTRATION... Correlation of bioavailability with an acute pharmacological effect or clinical evidence. Correlation of in...

  13. 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,

  14. Measurement of soil lead bioavailability and influence of soil types and properties: A review.

    Science.gov (United States)

    Yan, Kaihong; Dong, Zhaomin; Wijayawardena, M A Ayanka; Liu, Yanju; Naidu, Ravi; Semple, Kirk

    2017-10-01

    Lead (Pb) is a widespread heavy metal which is harmful to human health, especially to young children. To provide a human health risk assessment that is more relevant to real conditions, Pb bioavailability in soils is increasingly employed in the assessment procedure. Both in vivo and in vitro measurements for lead bioavailability are available. In vivo models are time- consuming and expensive, while in vitro models are rapid, economic, reproducible, and reliable while involving more uncertainties. Uncertainties in various measurements create difficulties in accurately predicting Pb bioavailability, resulting in the unnecessary remediation of sites. In this critical review, we utilised available data from in vivo and in vitro studies to identify the key parameters influencing the in vitro measurements, and presented uncertainties existing in Pb bioavailability measurements. Soil type, properties and metal content are reported to influence lead bioavailability; however, the differences in methods for assessing bioavailability and the differences in Pb source limit one's ability to conduct statistical analyses on influences of soil factors on Pb bioavailability. The information provided in the review is fundamentally useful for the measurement of bioavailability and risk assessment practices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Optimizing Oral Bioavailability in Drug Discovery: An Overview of Design and Testing Strategies and Formulation Options.

    Science.gov (United States)

    Aungst, Bruce J

    2017-04-01

    For discovery teams working toward new, orally administered therapeutic agents, one requirement is to attain adequate systemic exposure after oral dosing, which is best accomplished when oral bioavailability is optimized. This report summarizes the bioavailability challenges currently faced in drug discovery, and the design and testing methods and strategies currently utilized to address the challenges. Profiling of discovery compounds usually includes separate assessments of solubility, permeability, and susceptibility to first-pass metabolism, which are the 3 most likely contributors to incomplete oral bioavailability. An initial assessment of absorption potential may be made computationally, and high throughput in vitro assays are typically performed to prioritize compounds for in vivo studies. The initial pharmacokinetic study is a critical decision point in compound evaluation, and the importance of the effect the dosing vehicle or formulation can have on oral bioavailability, especially for poorly water soluble compounds, is emphasized. Dosing vehicles and bioavailability-enabling formulations that can be used for discovery and preclinical studies are described. Optimizing oral bioavailability within a chemical series or for a lead compound requires identification of the barrier limiting bioavailability, and methods used for this purpose are outlined. Finally, a few key guidelines are offered for consideration when facing the challenges of optimizing oral bioavailability in drug discovery. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  16. EFFECT OF SOIL PROPERTIES ON LEAD BIOAVAILABILITY AND TOXCITY TO EARTHWORMS

    Science.gov (United States)

    Soil properties are important factors modifying metal bioavailability to ecological receptors. Twenty-one soils with a wide range of soil properties were amended with a single concentration of Pb (2000 mg/kg) to determine the effects of soil properties on Pb bioavailability and ...

  17. Red wine is a poor source of bioavailable flavonols in men

    NARCIS (Netherlands)

    De Vries, Jeanne H M; Hollman, Peter C H; Van Amersfoort, Ingrid; Olthof, Margreet R.; Katan, Martijn B.

    2001-01-01

    Red wine is a source of polyphenolic antioxidants, of which flavonols such as quercetin are representatives. Red wine might therefore prevent LDL oxidation and atherosclerosis. However, data on the bioavailability of flavonols from wine are lacking. Therefore, we compared the bioavailability of

  18. Bioavailability of prednisolone in rabbits: Comparison of a highviscosity gel and an aqueous suspension - single- and repeated applications

    DEFF Research Database (Denmark)

    Johansen, Sven; Rask-Pedersen, Eva; Prause, J.U.

    1994-01-01

    Øjenpatologi, carbomer, vehicle, fusidic acid, ophthalmic bioavailability, rabbit, aqueous suspension, prednisolone acetate, sulfacetamide sodium......Øjenpatologi, carbomer, vehicle, fusidic acid, ophthalmic bioavailability, rabbit, aqueous suspension, prednisolone acetate, sulfacetamide sodium...

  19. 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 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...

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

    DEFF Research Database (Denmark)

    Rasmussen, Lasse Dam; Sørensen, S. J.; Turner, R. R.

    2000-01-01

    A previously described bioassay using a mer-lux gene fusion for detection of bioavailable mercury was applied for the estimation of the bioavailable fraction of mercury in soil. The bioavailable fraction is defined here as being part of the water leachable fraction. Due to masking of light emission...... 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....

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

    International Nuclear Information System (INIS)

    Strong-Gunderson, J.M.; Palumbo, A.V.; Applegate, B.; Saylor, G.S.

    1993-01-01

    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

  2. Chemodynamics of chromium reduction in soils: Implications to bioavailability

    Energy Technology Data Exchange (ETDEWEB)

    Choppala, Girish [Centre for Environmental Risk Assessment and Remediation, Building-X, University of South Australia, Mawson Lakes, South Australia 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, PO Box 486, Salisbury, South Australia 5106 (Australia); Bolan, Nanthi, E-mail: Nanthi.Bolan@unisa.edu.au [Centre for Environmental Risk Assessment and Remediation, Building-X, University of South Australia, Mawson Lakes, South Australia 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, PO Box 486, Salisbury, South Australia 5106 (Australia); Seshadri, Balaji [Centre for Environmental Risk Assessment and Remediation, Building-X, University of South Australia, Mawson Lakes, South Australia 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, PO Box 486, Salisbury, South Australia 5106 (Australia)

    2013-10-15

    Highlights: • Examined the effects of sorption, pH and C sources on Cr(VI) reduction and toxicity. • The rate of Cr(VI) reduction decreased with an increase in Cr(VI) adsorption and pH. • The proton dynamics in Cr(VI) reduction was assessed in relation to remediation. • A novel black carbon showed the highest reduction rate of Cr(VI) in soils. • Black carbon decreased the bioavailability and phytotoxicity of Cr(VI) in soils. -- Abstract: Chromium toxicity in soils can be mitigated by reduction of Cr(VI) to Cr(III) which is influenced by the presence of free Cr(VI) species in soil solution, and the supply of protons and electrons. In this study, the effects of Cr(VI) adsorption (i.e. availability of free Cr(VI) species in soil solution), soil pH (i.e. supply of protons) and three electron donor carbon sources [black carbon (BC), chicken manure biochar (CMB) and cow manure (CM)] on the reduction of Cr(VI) to Cr(III) in soils were investigated. The results indicated that the rate of Cr(VI) reduction decreased with an increase in Cr(VI) adsorption and soil pH, which is attributed to decreased supply of free Cr(VI) ions and protons, respectively. Among the three different amendments tested, BC showed the highest rate of Cr(VI) reduction followed by CM and CMB. Furthermore, addition of BC, CM and CMB decreased the bioavailability of Cr(VI) in contaminated soils. The high efficiency of BC on Cr(VI) reduction was due to the electron donor's functional groups such as phenolic, hydroxyl, carbonyl and amides. The study demonstrated that free form of Cr(VI) ions in soil solution and carbon amendments enriched with acidic functional groups favored the reduction of Cr(VI), thereby mitigating its bioavailability and toxicity in contaminated soils.

  3. Bioavailability of cadmium from infant diets in newborn rats

    International Nuclear Information System (INIS)

    Eklund, G.; Oskarsson, A.; Petersson Grawe, K.

    2001-01-01

    Infants are exposed to higher levels of cadmium (Cd) from infant and follow-on formulas than from breast milk. We studied the bioavailability of 109 CdCl 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 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 109 Cd in the whole body, in segments of rinsed small intestine and in tissue was measured in a gamma counter. Pups receiving 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 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 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, 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 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 109 Cd in the small intestine, leading to a prolonged absorption period, emphasizes the importance of extending studies on neonatal Cd absorption over a long time period in

  4. 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

  5. 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.

  6. Bioavailability of organically bound Fe to model phytoplankton of the Southern Ocean

    Directory of Open Access Journals (Sweden)

    C. S. Hassler

    2009-10-01

    Full Text Available Iron (Fe is known to be mostly bound to organic ligands and to limit primary productivity in the Southern Ocean. It is thus important to investigate the bioavailability of organically bound Fe. In this study, we used four phytoplankton species of the Southern Ocean (Phaeocystis sp., Chaetoceros sp., Fragilariopsis kerguelensis and Thalassiosira antarctica Comber to measure the influence of various organic ligands on Fe solubility and bioavailability. Short-term uptake Fe:C ratios were inversely related to the surface area to volume ratios of the phytoplankton. The ratio of extracellular to intracellular Fe is used to discuss the relative importance of diffusive supply and uptake to control Fe bioavailability. The effect of excess organic ligands on Fe bioavailability cannot be solely explained by their effect on Fe solubility. For most strains studied, the bioavailability of Fe can be enhanced relative to inorganic Fe in the presence of porphyrin, catecholate siderophore and saccharides whereas it was decreased in presence of hydroxamate siderophore and organic amine. For Thalassiosira, iron bioavailability was not affected by the presence of porphyrin, catecholate siderophore and saccharides. The enhancement of Fe bioavailability in presence of saccharides is presented as the result from both the formation of bioavailable (or chemically labile organic form of Fe and the stabilisation of Fe within the dissolved phase. Given the ubiquitous presence of saccharides in the ocean, these compounds might represent an important factor to control the basal level of soluble and bioavailable Fe. Results show that the use of model phytoplankton is promising to improve mechanistic understanding of Fe bioavailability and primary productivity in HNLC regions of the ocean.

  7. Determination of cadmium relative bioavailability in contaminated soils and its prediction using in vitro methodologies.

    Science.gov (United States)

    Juhasz, Albert L; Weber, John; Naidu, Ravi; Gancarz, Dorota; Rofe, Allan; Todor, Damian; Smith, Euan

    2010-07-01

    In this study, cadmium (Cd) relative bioavailability in contaminated (n = 5) and spiked (n = 2) soils was assessed using an in vivo mouse model following administration of feed containing soil or Cd acetate (reference material) over a 15 day exposure period. Cadmium relative bioavailability varied depending on whether the accumulation of Cd in the kidneys, liver, or kidney plus liver was used for relative bioavailability calculations. When kidney plus liver Cd concentrations were used, Cd relative bioavailability ranged from 10.1 to 92.1%. Cadmium relative bioavailability was higher (14.4-115.2%) when kidney Cd concentrations were used, whereas lower values (7.2-76.5%) were derived when liver Cd concentrations were employed in calculations. Following in vivo studies, four in vitro methodologies (SBRC, IVG, PBET, and DIN), encompassing both gastric and intestinal phases, were assessed for their ability to predict Cd relative bioavailability. Pearson correlations demonstrated a strong linear relationship between Cd relative bioavailability and Cd bioaccessibility (0.62-0.91), however, stronger in vivo-in vitro relationships were observed when Cd relative bioavailability was calculated using kidney plus liver Cd concentrations. Whereas all in vitro assays could predict Cd relative bioavailability with varying degrees of confidence (r(2) = 0.348-0.835), large y intercepts were calculated for a number of in vitro assays which is undesirable for in vivo-in vitro predictive models. However, determination of Cd bioaccessibility using the intestinal phase of the PBET assay resulted in a small y intercept (5.14; slope =1.091) and the best estimate of in vivo Cd relative bioavailability (r(2) = 0.835).

  8. 21 CFR 320.27 - Guidelines on the design of a multiple-dose in vivo bioavailability study.

    Science.gov (United States)

    2010-04-01

    ... vivo bioavailability study. 320.27 Section 320.27 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 § 320.27...

  9. Development of a Passive Multisampling Method to Measure Dioxins/Furans and Other Contaminant Bioavailability in Aquatic Sediments

    Science.gov (United States)

    2016-11-01

    FINAL REPORT Development of a Passive Multisampling Method to Measure Dioxins/Furans and Other Contaminant Bioavailability in Aquatic...passive multisampling method to measure Dioxins/Furans 5a. CONTRACT NUMBER and other contaminant bioavailability in aquatic sediments...This also indicates the bioavailability or pressure (fugacity) of contaminants on organisms2 and consequently represents the exposure level for

  10. Bioavailability of energy-effluent materials in coastal ecosystems

    International Nuclear Information System (INIS)

    Hardy, J.T.

    1987-01-01

    An attempt is made to study the long-term effects of effluents from coastal and offshore nuclear power plants. The original intent of the program was to integrate approaches in chemistry, ocean transport, and biological uptake to quantify the variables that regulate biological availability of energy-effluent materials. Initial work was focused on the fate and effects of copper. In later research, the authors examined the basic environmental variables controlling the bioavailability of energy-related contaminants. They investigated how factors such as dissolved organic compounds, suspended particles, and sediment binding affected chemical speciation and how chemical speciation, in turn, influenced the availability of metals and radionuclides to marine invertebrates. They developed a hydrodynamic model to predict sediment and contaminant transport, and they quantified the bioconcentration of synthetic-fuel residuals in plankton

  11. Assessing biochar's ability to reduce bioavailability of aminocyclopyrachlor in soils

    International Nuclear Information System (INIS)

    Rittenhouse, Jennifer L.; Rice, Pamela J.; Spokas, Kurt A.; Koskinen, William C.

    2014-01-01

    Aminocyclopyrachlor is a pyrimidine carboxylic acid herbicide used to control broadleaf weeds and brush. Amending soil with activated charcoal is recommended to prevent off-site transport of aminocyclopyrachlor and non-target plant damage. We used the batch-equilibrium method to determine the concentration of aminocyclopyrachlor in a pseudo-steady state with biochar, soil, and biochar-soil systems ( 5  kg ha −1 –7.27 × 10 5  kg ha −1 ). - Highlights: • Aminocyclopyrachlor is mobile in three Minnesota soils. • Biochar amendments had limited use for aminocyclopyrachlor remediation in soil. • Two biochar amendments consistently reduced the aqueous-phase herbicide. • Biochar inputs would be very high and not feasible for field-scale remediation. - This was the first study to assess the use of biochar as a remediation tool for reducing bioavailable aminocyclopyrachlor in the liquid phase soil systems

  12. Bioavailability and impact of effluents on coastal ecosystems

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    The Bioavailability and Impact of Effluents on Coastal Ecosystems program was initiated in July 1974. The program's major objective was to bring together a multidisciplinary team of researchers to investigate the biogeochemical processes that control the transport, transfer, distribution, biological availability and toxicity of materials found in energy-related effluents. This year has been spent in planning the needed research tasks, assembling the necessary personnel and equipment, and initiating first stage research as defined by the program. The program is centered at the Marine Research Laboratory, Sequim, Washington, and involves scientists located at Sequim and Richland. The operating philosophy is to conduct the program at the Marine Research Laboratory and use equipment and expertise from Richland as a resource for studies that cannot be practically done at Sequim. The research described represents the first year's efforts by the investigators involved in the program

  13. Vitamin D bioavailability in cystic fibrosis: a cause for concern?

    Science.gov (United States)

    Mailhot, Geneviève

    2012-05-01

    Despite the inclusion of extra vitamin D in their regimen of fat-soluble vitamin supplementation, cystic fibrosis patients remain chronically depleted of vitamin D. The persistence of suboptimal vitamin D status is often blamed on the maldigestion and malabsorption of fat. However, the mitigated success of recent clinical trials with high-dose vitamin D supplementation suggests that vitamin D bioavailability might be impaired in these patients. Given the growing understanding of the importance of this vitamin in the regulation of multiple biological functions beyond skeletal health, the present review analyzes the current literature by addressing each step of vitamin D metabolism and action in the context of this life-limiting pathology. In addition, it highlights the importance of vitamin D in relation to organs and or conditions affected by cystic fibrosis. © 2012 International Life Sciences Institute.

  14. Improving oral bioavailability of cyclic peptides by N-methylation.

    Science.gov (United States)

    Räder, Andreas F B; Reichart, Florian; Weinmüller, Michael; Kessler, Horst

    2018-06-01

    The renaissance of peptides in pharmaceutical industry results from their importance in many biological functions. However, low metabolic stability and the lack of oral availability of most peptides is a certain limitation. Whereas metabolic instability may be often overcome by development of small cyclic peptides containing d-amino acids, the very low oral availability of most peptides is a serious limitation for some medicinal applications. The situation is complicated because a twofold optimization - biological activity and oral availability - is required to overcome this problem. Moreover, most simple "rules" for achieving oral availability are not general and are applicable only to limited cases. Many structural modifications for increasing biological activities and metabolic stabilities of cyclic peptides have been described, of which N-alkylation is probably the most common. This mini-review focuses on the effects of N-methylation of cyclic peptides in strategies to optimize bioavailabilities. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Metabolism, oral bioavailability and pharmacokinetics of chemopreventive kaempferol in rats

    Science.gov (United States)

    Barve, Avantika; Chen, Chi; Hebbar, Vidya; Desiderio, Joseph; Saw, Constance Lay-Lay; Kong, Ah-Ng

    2012-01-01

    The purpose of this study was to compare the hepatic and small intestinal metabolism, and examine bioavailability and gastro-intestinal first-pass effects of Kaempferol in the rats. Liver and small intestinal microsomes fortified with either NADPH or UDPGA were incubated with varying concentrations of Kaempferol for upto 120 minutes. Based on the values of the kinetic constants (Km and Vmax), the propensity for UDPGA-dependent conjugation as compared to NADPH-dependent oxidative metabolism was higher for both hepatic and small intestinal microsomes. Male Sprague-Dawley rats were administered Kaempferol intravenously (IV) (10, 25 mg/kg) or orally (100, 250 mg/kg). Gastro-intestinal first pass effects were observed by collecting portal blood after oral administration of 100 mg/kg Kaempferol. Pharmacokinetic parameters were obtained by Noncompartmental analysis using WinNonlin. After IV administration, the plasma concentration-time profiles for 10 and 25 mg/kg were consistent with high clearance (~ 3 L/hr/kg) and large volumes of distribution (8-12 L/kg). The disposition was characterized by a terminal half-life value of 3-4 hours. After oral administration the plasma concentration-time profiles demonstrated fairly rapid absorption (tmax ~ 1-2 hours). The area under the curve (AUC) values after IV and oral doses increased proportional to the dose. The bioavailability (F) was poor at ~ 2%. Analysis of portal plasma after oral administration revealed low to moderate absorption. Taken together, the low F of Kaempferol is attributed in part to extensive first-pass metabolism by glucuronidation and other metabolic pathways in the gut and in the liver. PMID:19722166

  16. Improving maraviroc oral bioavailability by formation of solid drug nanoparticles.

    Science.gov (United States)

    Savage, Alison C; Tatham, Lee M; Siccardi, Marco; Scott, Trevor; Vourvahis, Manoli; Clark, Andrew; Rannard, Steve P; Owen, Andrew

    2018-05-17

    Oral drug administration remains the preferred approach for treatment of HIV in most patients. Maraviroc (MVC) is the first in class co-receptor antagonist, which blocks HIV entry into host cells. MVC has an oral bioavailability of approximately 33%, which is limited by poor permeability as well as affinity for CYP3A and several drug transporters. While once-daily doses are now the favoured option for HIV therapy, dose-limiting postural hypotension has been of theoretical concern when administering doses high enough to achieve this for MVC (particularly during coadministration of enzyme inhibitors). To overcome low bioavailability and modify the pharmacokinetic profile, a series of 70 wt% MVC solid drug nanoparticle (SDN) formulations (containing 30 wt% of various polymer/surfactant excipients) were generated using emulsion templated freeze-drying. The lead formulation contained PVA and AOT excipients ( MVC SDN PVA/AOT ), and was demonstrated to be fully water-dispersible to release drug nanoparticles with z-average diameter of 728 nm and polydispersity index of 0.3. In vitro and in vivo studies of MVC SDN PVA/AOT showed increased apparent permeability of MVC, compared to a conventional MVC preparation, with in vivo studies in rats showing a 2.5-fold increase in AUC (145.33 vs. 58.71 ng h ml -1 ). MVC tissue distribution was similar or slightly increased in tissues examined compared to the conventional MVC preparation, with the exception of the liver, spleen and kidneys, which showed statistically significant increases in MVC for MVC SDN PVA/AOT . These data support a novel oral format with the potential for dose reduction while maintaining therapeutic MVC exposure and potentially enabling a once-daily fixed dose combination product. Copyright © 2018. Published by Elsevier B.V.

  17. How bioavailable is highly weathered Deepwater Horizon oil?

    Science.gov (United States)

    Bostic, J.; Ziolkowski, L. A.; Reddy, C. M.; Aeppli, C.; Swarthout, B.

    2016-02-01

    Oiled sand patties continue to be deposited on northern Gulf of Mexico beaches five years after the Deepwater Horizon (DwH) oil spill. It is known that during the first 18 months post-spill, sand patties from DwH were chemically transformed, both biotically and abiotically, from wellhead release to beach deposition. However, the chemically transformed oil, which appears to become more polar over time, is not well understood in regards to its biodegradation potential. Biodegradation exerts a large control on the fate of spilled oil, representing a major conduit for its removal from the environment. To assess the bioavailability of this weathered oil, sand patties were collected from intertidal and supratidal zones of beaches in Florida, Alabama, and Mississippi in July 2015. Microbial biomarkers of the viable community, phospholipid fatty acids (PLFA), were detected on all samples collected. The PLFA distributions (mostly saturated and branched structures) and abundances (2 - 9 x 1013 cells/g sand patty) were similar across sampling locations. The positive correlation between PLFA abundance and surface area to volume ratios of sand patties indicates that microbes are preferentially inhabiting outside surfaces of the patties. We will present data on the radiocarbon (14C) content of PLFA to assess carbon (C) sources assimilated by microbes. 14C of PLFA is a powerful tool for assessing C sources assimilated in this setting. Oil has no 14C (Δ14C= -1000‰) while modern organic matter has relatively abundant 14C (Δ14C= 0‰). Fingerprinting analysis of biomarker ratios using comprehensive two-dimensional gas chromatography will be presented to ascertain if oil originated from DwH. The extent of the chemical transformation of the oil into more polar compounds will also be measured using thin layer chromatography. Results of this investigation aim to determine the bioavailability and ultimate fate of oiled sand patties that continue to wash ashore on Gulf of Mexico

  18. Using SPME fibers and Tenax to predict the bioavailability of pyrethroids and chlorpyrifos in field sediments

    International Nuclear Information System (INIS)

    Harwood, Amanda D.; Landrum, Peter F.; Weston, Donald P.; Lydy, Michael J.

    2013-01-01

    The presence of pyrethroids in both urban and agricultural sediments at levels lethal to invertebrates has been well documented. However, variations in bioavailability among sediments make accurate predictions of toxicity based on whole sediment concentrations difficult. A proposed solution to this problem is the use of bioavailability-based estimates, such as solid phase microextraction (SPME) fibers and Tenax beads. This study compared three methods to assess the bioavailability and ultimately toxicity of pyrethroid pesticides including field-deployed SPME fibers, laboratory-exposed SPME fibers, and a 24-h Tenax extraction. The objective of the current study was to compare the ability of these methods to quantify the bioavailable fraction of pyrethroids in contaminated field sediments that were toxic to benthic invertebrates. In general, Tenax proved a more sensitive method than SPME fibers and a correlation between Tenax extractable concentrations and mortality was observed. - Highlights: ► Can use bioavailability-based methods for pyrethroids in sediments. ► Tenax was a more sensitive technique. ► Tenax extractable concentrations relate to invertebrate mortality. - This research provides an important first step in using bioavailability-based techniques for estimating the bioavailability and toxicity of hydrophobic pesticides in field sediments.

  19. Improving the accuracy of effect-directed analysis: the role of bioavailability.

    Science.gov (United States)

    You, Jing; Li, Huizhen

    2017-12-13

    Aquatic ecosystems have been suffering from contamination by multiple stressors. Traditional chemical-based risk assessment usually fails to explain the toxicity contributions from contaminants that are not regularly monitored or that have an unknown identity. Diagnosing the causes of noted adverse outcomes in the environment is of great importance in ecological risk assessment and in this regard effect-directed analysis (EDA) has been designed to fulfill this purpose. The EDA approach is now increasingly used in aquatic risk assessment owing to its specialty in achieving effect-directed nontarget analysis; however, a lack of environmental relevance makes conventional EDA less favorable. In particular, ignoring the bioavailability in EDA may cause a biased and even erroneous identification of causative toxicants in a mixture. Taking bioavailability into consideration is therefore of great importance to improve the accuracy of EDA diagnosis. The present article reviews the current status and applications of EDA practices that incorporate bioavailability. The use of biological samples is the most obvious way to include bioavailability into EDA applications, but its development is limited due to the small sample size and lack of evidence for metabolizable compounds. Bioavailability/bioaccessibility-based extraction (bioaccessibility-directed and partitioning-based extraction) and passive-dosing techniques are recommended to be used to integrate bioavailability into EDA diagnosis in abiotic samples. Lastly, the future perspectives of expanding and standardizing the use of biological samples and bioavailability-based techniques in EDA are discussed.

  20. 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.

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

    Science.gov (United States)

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

    2016-01-01

    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.

  2. Aluminum bioavailability from basic sodium aluminum phosphate, an approved food additive emulsifying agent, incorporated in cheese.

    Science.gov (United States)

    Yokel, Robert A; Hicks, Clair L; Florence, Rebecca L

    2008-06-01

    Oral aluminum (Al) bioavailability from drinking water has been previously estimated, but there is little information on Al bioavailability from foods. It was suggested that oral Al bioavailability from drinking water is much greater than from foods. The objective was to further test this hypothesis. Oral Al bioavailability was determined in the rat from basic [26Al]-sodium aluminum phosphate (basic SALP) in a process cheese. Consumption of approximately 1g cheese containing 1.5% or 3% basic SALP resulted in oral Al bioavailability (F) of approximately 0.1% and 0.3%, respectively, and time to maximum serum 26Al concentration (Tmax) of 8-9h. These Al bioavailability results were intermediate to previously reported results from drinking water (F approximately 0.3%) and acidic-SALP incorporated into a biscuit (F approximately 0.1%), using the same methods. Considering the similar oral bioavailability of Al from food vs. water, and their contribution to the typical human's daily Al intake ( approximately 95% and 1.5%, respectively), these results suggest food contributes much more Al to systemic circulation, and potential Al body burden, than does drinking water. These results do not support the hypothesis that drinking water provides a disproportionate contribution to total Al absorbed from the gastrointestinal tract.

  3. In Vitro Iron Bioavailability of Brazilian Food-Based by-Products.

    Science.gov (United States)

    Chiocchetti, Gabriela M; De Nadai Fernandes, Elisabete A; Wawer, Anna A; Fairweather-Tait, Susan; Christides, Tatiana

    2018-05-16

    Background : Iron deficiency is a public health problem in many low- and middle-income countries. Introduction of agro-industrial food by-products, as additional source of nutrients, could help alleviate this micronutrient deficiency, provide alternative sources of nutrients and calories in developed countries, and be a partial solution for disposal of agro-industry by-products. Methods : The aim of this study was to determine iron bioavailability of 5 by-products from Brazilian agro-industry (peels from cucumber, pumpkin, and jackfruit, cupuaçu seed peel, and rice bran), using the in vitro digestion/ Caco-2 cell model; with Caco-2 cell ferritin formation as a surrogate marker of iron bioavailability. Total and dialyzable Fe, macronutrients, the concentrations of iron-uptake inhibitors (phytic acid, tannins, fiber) and their correlation with iron bioavailability were also evaluated. Results : The iron content of all by-products was high, but the concentration of iron and predicted bioavailability were not related. Rice bran and cupuaçu seed peel had the highest amount of phytic acid and tannins, and lowest iron bioavailability. Cucumber peels alone, and with added extrinsic Fe, and pumpkin peels with extrinsic added iron, had the highest iron bioavailability. Conclusion : The results suggest that cucumber and pumpkin peel could be valuable alternative sources of bioavailable Fe to reduce iron deficiency in at-risk populations.

  4. Causal inference between bioavailability of heavy metals and environmental factors in a large-scale region

    International Nuclear Information System (INIS)

    Liu, Yuqiong; Du, Qingyun; Wang, Qi; Yu, Huanyun; Liu, Jianfeng; Tian, Yu; Chang, Chunying; Lei, Jing

    2017-01-01

    The causation between bioavailability of heavy metals and environmental factors are generally obtained from field experiments at local scales at present, and lack sufficient evidence from large scales. However, inferring causation between bioavailability of heavy metals and environmental factors across large-scale regions is challenging. Because the conventional correlation-based approaches used for causation assessments across large-scale regions, at the expense of actual causation, can result in spurious insights. In this study, a general approach framework, Intervention calculus when the directed acyclic graph (DAG) is absent (IDA) combined with the backdoor criterion (BC), was introduced to identify causation between the bioavailability of heavy metals and the potential environmental factors across large-scale regions. We take the Pearl River Delta (PRD) in China as a case study. The causal structures and effects were identified based on the concentrations of heavy metals (Zn, As, Cu, Hg, Pb, Cr, Ni and Cd) in soil (0–20 cm depth) and vegetable (lettuce) and 40 environmental factors (soil properties, extractable heavy metals and weathering indices) in 94 samples across the PRD. Results show that the bioavailability of heavy metals (Cd, Zn, Cr, Ni and As) was causally influenced by soil properties and soil weathering factors, whereas no causal factor impacted the bioavailability of Cu, Hg and Pb. No latent factor was found between the bioavailability of heavy metals and environmental factors. The causation between the bioavailability of heavy metals and environmental factors at field experiments is consistent with that on a large scale. The IDA combined with the BC provides a powerful tool to identify causation between the bioavailability of heavy metals and environmental factors across large-scale regions. Causal inference in a large system with the dynamic changes has great implications for system-based risk management. - Causation between the

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

    International Nuclear Information System (INIS)

    Pauget, B.; Gimbert, F.; Scheifler, R.; Coeurdassier, M.; Vaufleury, A. de

    2012-01-01

    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 4 , EDTA, CaCl 2 , NH 4 NO 3 , NaNO 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 (r² 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 (r² 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: ► New approach to identify chemical methods able to predict metal bioavailability to snails. ► Bioavailability of cadmium, lead and zinc to snails was determined by

  6. 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

  7. Bioavailability and Uptake of Lead by Coffeeweed (Sesbania exaltata Raf.

    Directory of Open Access Journals (Sweden)

    Gloria Miller

    2008-12-01

    Full Text Available Lead (Pb is recognized as one of the most pervasive environmental health concerns in the industrialized world. While there has been a substantial reduction in the use of Pb in gasoline, water pipes, and Pb-based residential paint, residual Pb from their use is still in the environment and constitutes an important source of Pb in the atmosphere, water, and soil. Soil acts as a sink for these anthropogenic sources of Pb, accumulating the deposits over time in the upper 2 - 5 cm of undisturbed soil. Generally, Pb binds strongly to soil particles and renders a significant soil-metal fraction insoluble and largely unavailable for phytoremediation or plant uptake. A major objective of current phytoremediation research, therefore, is to induce desorption of Pb from the soil matrix into solution and increase the propensity for plant uptake. We hypothesized that the bioavailability of Pb for plant uptake can be increased through chelate amendments. To test this hypothesis, we mixed delta top soil and peat (2:1 and added lead nitrate [Pb (NO32] to generate a Pb-contaminated soil concentration of 2000 mg Pb/kg dry soil. After incubating the Pb-spiked soil in a greenhouse for 6 weeks, Sesbania plants were grown in the soil and harvested at 6, 8, and 10 weeks after emergence. Six days before each harvest, a chelating agent, ethylenediaminetetraacetic acid (EDTA was applied to the root zone as an aqueous solution in a 1:1 ratio with the Pb concentration in the soil. Sequential extraction procedures were used to assess selective chemical fractions of Pb in the soil. Our results showed that a higher exchangeable fraction of Pb was available for plant uptake after chelate amendment compared to pre-chelate amendment. We also saw higher root and shoot Pb uptake after chelate amendment compared to pre-chelate amendment, especially at 10 weeks after emergence. Together, these results suggest that chelate amendments can promote the bioavailability of Pb in the soil

  8. Speciation, Sources and Bioavailability of Copper and Zinc in DoD-Impacted Harbors and Estuaries

    National Research Council Canada - National Science Library

    Shafer, Martin; Tang, Degui; Hemming, Jocelyn; Beard, Brian; Armstrong, David

    2007-01-01

    .... The overarching goal of this SERDP project was to advance our understanding of metal-ligand binding in order to further the development of practical and predictive models of trace metal bioavailability...

  9. A review of methods for assessment of trace element bioavailability in humans

    International Nuclear Information System (INIS)

    Ahmad, T.; Bilal, R.

    2001-01-01

    Deficiency of micronutrients is widespread among the low socio-economic strata of population. Different intervention strategies are used to eradicate these deficiencies. The most important step in the confirmation of the efficacy/success of an intervention is bioavailability. There are a number of methods for determining the bioavailability, involving both nuclear and non-nuclear techniques. Traditionally, bioavailability of different micronutrients was determined using the chemical balance method, that is, amount excreted subtracted from the amount ingested. Nowadays, methodologies have been developed for measuring the bioavailability of different trace elements incorporating the use of isotopes. The isotopic techniques are very accurate and highly specific. This paper summarizes the various methodologies available with special emphasis on nuclear methods. (author)

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. DIGESTIVE BIOAVAILABILITY TO A DEPOSIT FEDDER (ARENICOLA MARINA) OF POLYCYCLIC AROMATIC HYDROCARBONS ASSOCIATED WITH ANTHRPOGENIC PARTICLES

    Science.gov (United States)

    Marine sediments around urban areas serve as catch basins for anthropogenic particles containing polycyclic aromatic hydrocarbons (PAHs). Using incubations with gut fluids extracted from a deposit-feeding polychaete (Arenicola marina), we determined the digestive bioavailability ...

  15. Ionic Strength Differentially Affects the Bioavailability of Neutral and Negatively Charged Inorganic Hg Complexes.

    Science.gov (United States)

    Stenzler, Benjamin; Hinz, Aaron; Ruuskanen, Matti; Poulain, Alexandre J

    2017-09-05

    Mercury (Hg) bioavailability to bacteria in marine systems is the first step toward its bioamplification in food webs. These systems exhibit high salinity and ionic strength that will both alter Hg speciation and properties of the bacteria cell walls. The role of Hg speciation on Hg bioavailability in marine systems has not been teased apart from that of ionic strength on cell wall properties, however. We developed and optimized a whole-cell Hg bioreporter capable of functioning under aerobic and anaerobic conditions and exhibiting no physiological limitations of signal production to changes in ionic strength. We show that ionic strength controls the bioavailability of Hg species, regardless of their charge, possibly by altering properties of the bacterial cell wall. The unexpected anaerobic bioavailability of negatively charged halocomplexes may help explain Hg methylation in marine systems such as the oxygen-deficient zone in the oceanic water column, sea ice or polar snow.

  16. An efficient method for estimating bioavailability of arsenic in soils: a comparison with acid leachates

    Energy Technology Data Exchange (ETDEWEB)

    Ng, J.C.; Hertle, A.; Seawright, A.A. [Queensland Univ., Brisbane (Australia). National Research Centre for Environmental Toxicology; Mcdougall, K.W. [Wollongbar Agricultural Institute (Australia)

    1997-12-31

    With the view of estimating bioavailability of metals from contaminated sites and risk assessment, a rat model is used for a comparative bioavailability test in which groups of rats were given via the oral route a slurry of arsenic contaminated soils, a solution of sodium arsenate or sodium arsenite, or calcium arsenite spiked wheat flour. Blood samples are collected 96 hours after dosing for the arsenic determination. The comparative bioavailability (CBA) is calculated from the ratio of arsenic results obtained from the soil group and arsenic control group dosed with sodium arsenate or arsenite. CBA results show a good correlation with 0.5 M HCl and 1.0 M HCl acid leachates. The rat model process to be a sensitive indicator using the blood for the study of bioavailability of arsenic in soils

  17. Environmental fate of TCDD and Agent Orange and bioavailability to troops in Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Karch, N.J.; Watkins, D.K.; Ginevan, M.E. [Exponent, Inc., Washington, DC (United States); Young, A.L. [Oklahoma Univ., Norman, OK (United States)

    2004-09-15

    This paper reviews the environmental fate of Agent Orange and the contaminant, 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD), and discusses how this affects the bioavailability of TCDD for ground troops in Vietnam.

  18. 4-(Phenylsulfonyl)piperidines: novel, selective, and bioavailable 5-HT(2A) receptor antagonists.

    Science.gov (United States)

    Fletcher, Stephen R; Burkamp, Frank; Blurton, Peter; Cheng, Susan K F; Clarkson, Robert; O'Connor, Desmond; Spinks, Daniel; Tudge, Matthew; van Niel, Monique B; Patel, Smita; Chapman, Kerry; Marwood, Rose; Shepheard, Sara; Bentley, Graham; Cook, Gina P; Bristow, Linda J; Castro, Jose L; Hutson, Peter H; MacLeod, Angus M

    2002-01-17

    On the basis of a spirocyclic ether screening lead, a series of acyclic sulfones have been identified as high-affinity, selective 5-HT(2A) receptor antagonists. Bioavailability lacking in the parent, 1-(2-(2,4-difluorophenyl)ethyl)-4-(phenylsulfonyl)piperidine (12), was introduced by using stability toward rat liver microsomes as a predictor of bioavailability. By this means, the 4-cyano- and 4-carboxamidophenylsulfonyl derivatives 26 and 31 were identified as orally bioavailable, brain-penetrant analogues suitable for evaluation in animal models. Bioavailability was also attainable by N substitution leading to the N-phenacyl derivative 35. IKr activity detected through counterscreening was reduced to insignificant levels in vivo with the latter compound.

  19. Recent Developments in Delivery, Bioavailability, Absorption and Metabolism of Curcumin: the Golden Pigment from Golden Spice

    OpenAIRE

    Prasad, Sahdeo; Tyagi, Amit K.; Aggarwal, Bharat B.

    2014-01-01

    Curcumin (diferuloylmethane) is a yellow pigment present in the spice turmeric (Curcuma longa) that has been associated with antioxidant, anti-inflammatory, anticancer, antiviral, and antibacterial activities as indicated by over 6,000 citations. In addition, over one hundred clinical studies have been carried out with curcumin. One of the major problems with curcumin is perceived to be the bioavailability. How curcumin should be delivered in vivo, how bioavailable is it, how well curcumin is...

  20. Chemistry, Toxicity, and Bioavailability of Copper and its Relationship to Regulation in the Marine Environment

    Science.gov (United States)

    1998-11-01

    The majority (70%) of commercial ship hulls still use tributyltin ( TBT ) coatings, which also contain approximately 30% to 40% copper. The Navy spends...TECHNICAL DOCUMENT 3044 November 1998 Chemistry, Toxicity , and Bioavailability of Copper and Its Relationship to Regulation in the Marine Environment...participated in a Workshop on Chemistry, Toxicity , and Bioavailability of Copper and Its Relationship to Regulation in the Marine Environment. The goal

  1. Causal inference between bioavailability of heavy metals and environmental factors in a large-scale region.

    Science.gov (United States)

    Liu, Yuqiong; Du, Qingyun; Wang, Qi; Yu, Huanyun; Liu, Jianfeng; Tian, Yu; Chang, Chunying; Lei, Jing

    2017-07-01

    The causation between bioavailability of heavy metals and environmental factors are generally obtained from field experiments at local scales at present, and lack sufficient evidence from large scales. However, inferring causation between bioavailability of heavy metals and environmental factors across large-scale regions is challenging. Because the conventional correlation-based approaches used for causation assessments across large-scale regions, at the expense of actual causation, can result in spurious insights. In this study, a general approach framework, Intervention calculus when the directed acyclic graph (DAG) is absent (IDA) combined with the backdoor criterion (BC), was introduced to identify causation between the bioavailability of heavy metals and the potential environmental factors across large-scale regions. We take the Pearl River Delta (PRD) in China as a case study. The causal structures and effects were identified based on the concentrations of heavy metals (Zn, As, Cu, Hg, Pb, Cr, Ni and Cd) in soil (0-20 cm depth) and vegetable (lettuce) and 40 environmental factors (soil properties, extractable heavy metals and weathering indices) in 94 samples across the PRD. Results show that the bioavailability of heavy metals (Cd, Zn, Cr, Ni and As) was causally influenced by soil properties and soil weathering factors, whereas no causal factor impacted the bioavailability of Cu, Hg and Pb. No latent factor was found between the bioavailability of heavy metals and environmental factors. The causation between the bioavailability of heavy metals and environmental factors at field experiments is consistent with that on a large scale. The IDA combined with the BC provides a powerful tool to identify causation between the bioavailability of heavy metals and environmental factors across large-scale regions. Causal inference in a large system with the dynamic changes has great implications for system-based risk management. Copyright © 2017 Elsevier Ltd. All

  2. The oral bioavailability of nitrate from vegetables investigated in healthy volunteers

    OpenAIRE

    Lambers AC; Kortboyer JM; Schothorst RC; Sips AJAM; Cleven RFMJ; Meulenbelt J; VIC; LBM; ARO; LAC

    2000-01-01

    The major source of human nitrate exposure comes from vegetables. Several studies were performed to estimate the total daily dietary nitrate intake based on the nitrate contents of food and drinking water. However, only nitrate that is absorbed from the gastro-intestinal tract may contribute to the toxicity of nitrate in the body. At present no data are available on the bioavailability of nitrate from vegetables. Therefore the present study was performed to evaluate the oral bioavailability o...

  3. Physicochemical Properties, Permeability and Bioavailability of Geraniin and Geraniin-Phospholipid Complex

    OpenAIRE

    SUMITA ELENDRAN

    2017-01-01

    Geraniin has been credited with a range of bioactive properties and therefore merits greater research into its potential pharmaceutical, nutraceutical and cosmetic applications. To clarify its functionalities and to explore future applications, a more comprehensive understanding of geraniin; its physiochemical, permeability, bioavailability and pharmacokinetic properties has become necessity. In light of geraniin’s anticipated poor bioavailability and to be considered as an oral drug candidat...

  4. A Pooled Data Analysis to Determine the Relationship between Selected Metals and Arsenic Bioavailability in Soil

    OpenAIRE

    Kaihong Yan; Ravi Naidu; Yanju Liu; Ayanka Wijayawardena; Luchun Duan; Zhaomin Dong

    2018-01-01

    Chronic exposure to arsenic (As) is a global concern due to worldwide exposure and adverse effects, and the importance of incorporating bioavailability in the exposure assessment and risk assessment of As is increasing acknowledged. The bioavailability of As is impacted by a number of soil properties, such as pH, clay and metal concentrations. By retrieving 485 data from 32 publications, the aim of this study was to determine the relationship between selected metals (Fe and Al) and As bioavai...

  5. Bioavailability of Isothiocyanates From Broccoli Sprouts in Protein, Lipid, and Fiber Gels

    OpenAIRE

    Oliviero, Teresa; Lamers, Simone; Capuano, Edoardo; Dekker, Matthijs; Verkerk, Ruud

    2018-01-01

    Scope: Optimization of bioavailability of dietary bioactive health-beneficial compounds is as important as increasing their concentration in foods. The aim of this study is to explore the change in bioavailability of isothiocyanates (ITCs) in broccoli sprouts incorporated in protein, fiber, and lipid gels. Methods and results: Five participants took part in a cross-over study and collected timed urine samples up to 24 h after consumption of proteins, dietary fibers, and lipid gels containing ...

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

    OpenAIRE

    Veldkamp, T.; Diepen, van, J.T.M.; 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...

  7. 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.

  8. Antioxidant flavonols from fruits, vegetables and beverages: measurements and bioavailability

    Directory of Open Access Journals (Sweden)

    ALAN CROZIER

    2000-01-01

    Full Text Available Flavonols are polyphenolic secondary plant metabolites that are present in varying levels in commonly consumed fruits, vegetables and beverages. Flavonols have long held an interest for nutritionists, which has increased following a Dutch study in the early 1990’s showing that dietary intake of flavonols was inversely correlated with the incidence of coronary heart disease. The main factors that have hindered workers in the field of flavonol research are (i the accurate measurement of these compounds in foods and biological samples, and (ii a dearth of information on their absorption and metabolism. This review aims to highlight the work of the authors in attempting to clarify the situation. The sensitive and selective HPLC procedure to identify and quantify common flavonols and their sugar conjugates is described. In addition, the results of an on-going screening program into the flavonol content of common produce and beverages are presented. The bioavailability of dietary flavonols is discussed with reference to an intervention study with onions, as well as pilot studies with tea, red wine and cherry tomatoes. It is concluded that flavonols are absorbable and accumulate in plasma and that consuming high flavonol-containing varieties of fruits and vegetables and particular types of beverages could increase their circulatory levels

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

    International Nuclear Information System (INIS)

    Stephenson, G.; Angell, R.; Strive, E.; Ma, W.

    2010-01-01

    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.

  10. Experimental studies on californium bioavailability to marine benthic invertebrates

    International Nuclear Information System (INIS)

    Fowler, S.W.; Carvalho, F.P.; Aston, S.R.

    1986-01-01

    252 Cf is readily taken up by benthic invertebrates from sea water, reaching whole-body concentration factors of 763 in the polychaete Hermione hystrix, 220 in the shrimp Lysmata seticaudata, 665 in the crab Pilumnus hirtellus and 78 in the bivalve mollusc Venerupis decussata after 3 weeks exposure. Surface sorption plays a predominant role in the uptake process. Depuration in clean sea water was a relatively slow process. The shrimp Lysmata eliminated 252 Cf very rapidly due to moulting. Absorption coefficients for ingested 252 Cf were high, approx. 23% in crabs and approx. 97% in brittlestars. The absorbed fraction was excreted twice as fast from crabs as brittlestars. Exposure of organisms to labelled sediment resulted in low transfer factors that were species dependent. There is some evidence to suggest that uptake from sediments is primarily due to 252 Cf transfer from the pore water. Comparison of these results with published experimental data on other transuranic nuclides in the same or similar species suggests that californium bioavailability is roughly equivalent to that of plutonium and americium. (author)

  11. Bioavailability study for the Paducah Gaseous Diffusion Plant

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, T.L.; Kszos, L.A.

    1996-08-01

    The overall purpose of this plan is to assess the bioavailability of metals in the continuous and intermittent outfalls. The results may be used to determine alternative metal limits that more appropriately measure the portion of metal present necessary for toxicity to aquatic life. These limits must remain protective of in-stream aquatic life; thus, the highest concentration of metal in the water will be determined concurrently with an assessment of acute or chronic toxicity on laboratory tests. Using the method developed by the Kentucky Division of Water (KDOW), biomonitoring results and chemical data will be used to recommend alternative metal limits for the outfalls of concern. The data will be used to meet the objectives of the study: (1) evaluate the toxicity of continuous outfalls and intermittent outfalls at Paducah Gaseous Diffusion Plant; (2) determine the mean ratio of dissolved to Total Recoverable metal for Cd, Cr, Cu, Pb, Ni, and Zn in the continuous and intermittent outfalls; (3) determine whether the concentration of total recoverable metal discharged causes toxicity to fathead minnows and /or Ceriodaphnia; and (4) determine alternative metal limits for each metal of concern (Cd, Cr, Cu, Pb, Ni, and Zn).

  12. Effects of irradiation of sewage sludge on heavy metal bioavailability

    International Nuclear Information System (INIS)

    Sheppard, S.C.; Mayoh, K.R.

    1986-10-01

    Sewage sludges are a valuable resource to agriculture, but their use is limited by the hazards of pathogens, toxic chemicals and heavy metals. Irradiation can control the pathogens and deactivate some of the toxic chemicals. The relative cost of industrial-scale irradiation using accelerators has decreased progressively. This, coupled with the increasing necessity to recycle wastes, has led to renewed interest in irradiation of sludges. In response to this renewed interest, this report examines what is known about the effects of irradiation on the bioavailability of heavy metals. Very few studies have addressed this topic, although workers in the U.S. have claimed decreased solubility of metals in irradiated sludges. We have also briefly reviewed the general literature on sludge to gain indirect evidence on the likely effects. The scant data, often based on less than ideal experimental methodologies, show no major consistent effects of irradiation on the availability of heavy metals from sludge. The data are not sufficient to rule out such effects entirely, but the effects appear to be fairly subtle and not likely to persist beyond one growth season. 85 refs

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

    International Nuclear Information System (INIS)

    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 μg 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

  14. Methods of Selenium Supplementation: Bioavailability and Determination of Selenium Compounds.

    Science.gov (United States)

    Bodnar, Malgorzata; Szczyglowska, Marzena; Konieczka, Piotr; Namiesnik, Jacek

    2016-01-01

    Selenium, a "dual-surface" element, maintains a very thin line between a level of necessity and harmfulness. Because of this, a deficiency or excess of this element in an organism is dangerous and causes health-related problems, both physically and mentally. The main source of selenium is a balanced diet, with a proper selection of meat and plant products. Meanwhile, the proper assimilation of selenium into these products depends on their bioavailability, bioaccessibility, and/or bioactivity of a given selenium compound. From the time when it was discovered that selenium and its compounds have a significant influence on metabolic processes and in many countries throughout the world, a low quantity of selenium was found in different parts of the environment, pressure was put upon an effective and fast method of supplementing the environment with the help of selenium. This work describes supplementation methods applied with the use of selenium, as well as new ideas for increasing the level of this element in various organisms. Based on the fact that selenium appears in the environment at trace levels, the determination of total amount of selenium or selenium speciation in a given sample demands the selection of appropriate measurement methods. These methods are most often comprised of a sample preparation technique and/or a separation technique as well as a detection system. The work presents information on the subject of analytical methods used for determining selenium and its compounds as well as examples in literature of their application.

  15. Acute inhibition of iron bioavailability by zinc: studies in humans.

    Science.gov (United States)

    Olivares, Manuel; Pizarro, Fernando; Ruz, Manuel; de Romaña, Daniel López

    2012-08-01

    Iron (Fe) and zinc (Zn) deficiencies constitute two of the most important nutritional and public health problems affecting developing countries. Combined supplementation or fortification with Zn and Fe are strategies that can be used to improve the Zn and Fe status of a population. However, there is concern about potential negative interactions between these two micronutrients due to a competitive binding to DMT1 and Zip14 transporter. Studies performed in humans have shown an inhibitory effect of Zn on Fe absorption when both minerals are given together as a solution in fasting conditions. We found that at low doses of iron (0.5 mg) the threshold for the inhibition of iron bioavailability was at a Zn:Fe wt/wt ratio ≥5.9:1, whereas at higher doses of Fe (10 mg) this inhibition occurred at 1:1 Zn:Fe wt/wt ratio. This differential response could be explained by the variation in the abundance of both cations as they compete for a limited number of shared transporters at the enterocyte. Conflicting results have been obtained when this interaction was studied in different food matrices. A negative interaction was not observed when Fe and Zn were provided in a composite hamburger meal, premature formula, human milk, or cow milk. A decrease on Fe absorption was observed in only 1 of 3 studies when Fe and Zn were supplied in wheat flour. The possibility of a negative interaction should be considered for supplementation or fortification programs with both microminerals.

  16. 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.

  17. Phospholipid Complex Technique for Superior Bioavailability of Phytoconstituents

    Directory of Open Access Journals (Sweden)

    Kattamanchi Gnananath

    2017-04-01

    Full Text Available Phytoconstituents have been utilized as medicines for thousands of years, yet their application is limited owing to major hurdles like deficit lipid solubility, large molecular size and degradation in the gastric environment of gut. Recently, phospholipid-complex technique has unveiled in addressing these stumbling blocks either by enhancing the solubilizing capacity or its potentiating ability to pass through the biological membranes and it also protects the active herbal components from degradation. Hence, this phospholipid-complex-technique can enable researchers to deliver the phytoconstituents into systemic circulation by using certain conventional dosage forms like tablets and capsules. This review highlights the unique property of phospholipids in drug delivery, their role as adjuvant in health benefits, and their application in the herbal medicine systems to improve the bioavailability of active herbal components. Also we summarize the prerequisites for phytosomes preparation like the selection of type of phytoconstituents, solvents used, various methods employed in phytosomal preparation and its characterization. Further we discuss the key findings of recent research work conducted on phospholipid-based delivery systems which can enable new directions and advancements to the development of herbal dosage forms.

  18. E-Peptides Control Bioavailability of IGF-1

    Science.gov (United States)

    Piszczek, Agnieszka; Perlas, Emarald; Winn, Nadine; Nastasi, Tommaso; Rosenthal, Nadia

    2012-01-01

    Insulin-like growth factor 1 (IGF-1) is a potent cytoprotective growth factor that has attracted considerable attention as a promising therapeutic agent. Transgenic over-expression of IGF-1 propeptides facilitates protection and repair in a broad range of tissues, although transgenic mice over-expressing IGF-1 propeptides display little or no increase in IGF-1 serum levels, even with high levels of transgene expression. IGF-1 propeptides are encoded by multiple alternatively spliced transcripts including C-terminal extension (E) peptides, which are highly positively charged. In the present study, we use decellularized mouse tissue to show that the E-peptides facilitate in vitro binding of murine IGF-1 to the extracellular matrix (ECM) with varying affinities. This property is independent of IGF-1, since proteins consisting of the E-peptides fused to relaxin, a related member of the insulin superfamily, bound equally avidly to decellularized ECM. Thus, the E-peptides control IGF-1 bioavailability by preventing systemic circulation, offering a potentially powerful way to tether IGF-1 and other therapeutic proteins to the site of synthesis and/or administration. PMID:23251442

  19. Bioavailability and biodegradation kinetics of organics in soil

    International Nuclear Information System (INIS)

    Tabak, H.H.; Govind, R.; Gao, Chao; Kim, In-soo; Lai, Lei

    1992-01-01

    As EPA begins to remediate Superfund sites using permanent treatment technologies, such as bioremediation, a fundamental understanding of the kinetics and the factors that control the rate of bioremediation will be required. Biological treatment technologies hold considerable promise for safe, economical, on-site treatment of toxic wastes. A variety of biological treatment systems designed to degrade or detoxify environmental contaminants are currently being developed and marketed. Knowledge of the kinetics of biodegradation is essential to the evaluation of the persistence of most organic pollutants in soil. Furthermore, measurement of biodegradation kinetics can provide useful insights into the favorable range of the important environmental parameters for improvement of the microbiological activity and consequently the enhancement of contaminant biodegradation. A major effort is currently underway to clean up aquifers and soils that are contaminated by organic chemicals, which has generated increased interest in the development of in situ bioremediation technologies. Although considerable data exists for rates of biodegradation in aquatic environments, there is little information on biodegradation kinetics in soil matrices, where irreversible binding to the soil phase may limit the chemicals bioavailability and ultimate degradation. Knowledge on biodegradation kinetics in soil environments can facilitate decisions on the efficacy of in situ bioremediation. 6 refs., 3 figs., 2 tabs

  20. 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.

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

    International Nuclear Information System (INIS)

    Sysoeva, A.A.; Konopleva, I.V.; Sanzharova, N.I.

    2005-01-01

    Parameters related to 90 Sr mobility in the soil-plant system are reported: exchangeable content, selectivity coefficient, and transfer factor. Large mobility of 90 Sr in different soil types was shown. The fraction of exchangeable 90 Sr varied between 70 and 90%. The selectivity coefficient K C ( 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 90 Sr biological availability. A static model was devised that describes 90 Sr sorption from soil solution by soil and on the root surface. The parameter of 90 Sr bioavailability (A) has been suggested. Parameter A was calculated from data on soil exchangeable Ca content and 90 Sr mobility indicators - exchangeable fraction of the radionuclide and the selectivity coefficient K C ( 90 Sr/Ca). A correlation was found between TF and parameter A

  2. Bioavailability and Pharmacodynamics of Promethazine in Human Subjects

    Science.gov (United States)

    Boyd, J. L.; Boster, B.; Wang, Z.; Shah, V.; Berens, K. L.; Sipes, W. E.; Anderson, K. E.; Putcha, L.

    2004-01-01

    The acute effects of exposure to microgravity include the development of space motion sickness, which usually requires therapeutic intervention. The current drug of choice, promethazine (PMZ), is available to astronauts in three different dosage forms during space flight; its side effects include nausea, dizziness, sedation and impaired psychomotor performance. This ground-based study is designed to validate flight-suitable methods for pharmacodynamic evaluation of PMZ and to estimate bioavailability and pharmacodynamics of PMZ. Experimental design consists of intramuscular administration of three doses of PMZ (12.5,25 and 50 mg) and placebo in a randomized double blind fashion to human subjects and collecting blood, urine and saliva samples for 72 h. Subjects also complete cognitive performance test batteries, WinSCAT (Windows based Space Cognitive Assessment Test) and ARES (ANAM Readiness Evaluation System). Preliminary results indicate a significant relationship (p=9.88e-05) between circulating PMZ levels and cognitive performance parameters. Time to accurately complete memory tasks increases significantly with concentrations; higher concentrations also increase response time and decrease accuracy of substitution and matching tasks. AUC and half-life estimates for PMZ ranged between 0.12 and 1.7 mg.h/L and 15 and 50 h, respectively. These preliminary results indicate that PMZ may exhibit dose-dependent pharmacokinetics in humans; also, WinSCAT and ARES are sensitive for pharmacodynamic assessment of PMZ, and may be applicable for assessing the pharmacodynamics of other neurocognitive drugs.

  3. Synthesis, stability and bioavailability of astaxanthin succinate diester.

    Science.gov (United States)

    Qiao, Xing; Yang, Lu; Zhang, Ting; Zhou, Qingxin; Wang, Yuming; Xu, Jie; Xue, Changhu

    2018-06-01

    We synthesized astaxanthin succinate diester (ASD), a novel astaxanthin (AST) derivate, with succinic anhydride and free AST. ASD was purified and characterized using silica gel column chromatography and spectrometry, respectively. The ASD final synthesis rate was 82.63%. A stability test revealed a high AST and ASD retention rate at pH 5.0-7.0. ASD showed better stability than did AST under acidic conditions. Both sample ions showed lower retention rates under Fe 2+ and Fe 3+ states. The ASD metabolic curve showed serum and liver area under the curve from 0 h to time t (AUC 0-t ) values of 45.05 ± 4.58 and 120.38 ± 23.66 µg h -1  mL -1 , respectively. The long-term accumulation was significantly higher in the ASD group than in the AST group, which showed higher accumulation in the heart, muscle and spleen than in other tissues in vivo. The thermal stability and bioavailability of ASD were higher than that of the non-esterified free AST and common free AST, respectively. Additionally, AST accumulation in different tissues of the ASD group was multifold higher than that of free AST. These results prove that ASD may serve as a better source of AST for human nutrition than does free AST. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  4. 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.

  5. Do constructed wetlands remove metals or increase metal bioavailability?

    Science.gov (United States)

    Xu, Xiaoyu; Mills, Gary L

    2018-07-15

    The H-02 wetland was constructed to treat building process water and storm runoff water from the Tritium Processing Facility on the Department of Energy's Savannah River Site (Aiken, SC). Monthly monitoring of copper (Cu) and zinc (Zn) concentrations and water quality parameters in surface waters continued from 2014 to 2016. Metal speciation was modeled at each sampling occasion. Total Cu and Zn concentrations released to the effluent stream were below the NPDES limit, and the average removal efficiency was 65.9% for Cu and 71.1% for Zn. The metal-removal processes were found out to be seasonally regulated by sulfur cycling indicated by laboratory and model results. High temperature, adequate labile organic matter, and anaerobic conditions during the warm months (February to August) favored sulfate reduction that produced sulfide minerals to significantly remove metals. However, the dominant reaction in sulfur cycling shifted to sulfide oxidation during the cool months (September to next March). High concentrations of metal-organic complexes were observed, especially colloidal complexes of metal and fulvic acid (FA), demonstrating adsorption to organic matter became the primary process for metal removal. Meanwhile, the accumulation of metal-FA complexes in the wetland system will cause negative effects to the surrounding environment as they are biologically reactive, highly bioavailable, and can be easily taken up and transferred to ecosystems by trophic exchange. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Intracellular Drug Bioavailability: Effect of Neutral Lipids and Phospholipids.

    Science.gov (United States)

    Treyer, Andrea; Mateus, André; Wiśniewski, Jacek R; Boriss, Hinnerk; Matsson, Pär; Artursson, Per

    2018-06-04

    Intracellular unbound drug concentrations are the pharmacologically relevant concentrations for targets inside cells. Intracellular drug concentrations are determined by multiple processes, including the extent of drug binding to intracellular structures. The aim of this study was to evaluate the effect of neutral lipid (NL) and phospholipid (PL) levels on intracellular drug disposition. The NL and/or PL content of 3T3-L1 cells were enhanced, resulting in phenotypes (in terms of morphology and proteome) reminiscent of adipocytes (high NL and PL) or mild phospholipidosis (only high PL). Intracellular bioavailability ( F ic ) was then determined for 23 drugs in these cellular models and in untreated wild-type cells. A higher PL content led to higher intracellular drug binding and a lower F ic . The induction of NL did not further increase drug binding but led to altered F ic due to increased lysosomal pH. Further, there was a good correlation between binding to beads coated with pure PL and intracellular drug binding. In conclusion, our results suggest that PL content is a major determinant of drug binding in cells and that PL beads may constitute a simple alternative to estimating this parameter. Further, the presence of massive amounts of intracellular NLs did not influence drug binding significantly.

  7. Influence of contact time and sediment composition on the bioavailability of Cd in sediments

    International Nuclear Information System (INIS)

    Zhong Huan; Kraemer, Lisa; Evans, Douglas

    2013-01-01

    Stable isotope 111 Cd was spiked into sediments of different organic content levels for 3 days to 2 months. Bioavailability of spiked Cd to deposit-feeders, assessed by in vitro Cd solubilization, generally decreased with contact time but became comparable with that of background Cd after 2 months. This could be explained by the gradual transfer of Cd from the more mobile geochemical phase (carbonate associated phase) to more refractory phases (Fe–Mn oxide associated phase, and organic associated phase) within 2 months. The sedimentary organic content had a weak effect on Cd solubilization, while the distribution of Cd in carbonate or Fe–Mn oxide associated phase could have a larger influence on the solubilization of sedimentary Cd and its change with contact time. The observations in this study emphasize the need to consider Cd sequestration over time in sediments of various compositions, which would be useful in risk assessment of contaminated sediments. Highlights: ► Cd may reach equilibrium in sediments after 2 months of aging. ► Sediment composition could affect change of Cd bioavailability with contact time. ► Sedimentary organic content has a weak effect on Cd bioavailability. ► Cd associated with carbonates is more bioavailable than Cd with Fe/Mn oxides. ► Change in Cd solid speciation explains decrease of Cd bioavailability over time. - Transfer of Cd from carbonate phase to Fe–Mn oxide phase in sediments was important in affecting the decrease of Cd bioavailability over time.

  8. Lead and zinc bioavailability to Eisenia fetida after phosphorus amendment to repository soils

    International Nuclear Information System (INIS)

    Ownby, David R.; Galvan, Kari A.; Lydy, Michael J.

    2005-01-01

    Four phosphorus forms were investigated as potential soil amendments to decrease the bioavailability of Pb and Zn in two repository soils to the earthworm, Eisenia fetida. Treatments were evaluated by examining differences in bioaccumulation factors between amended and non-amended soils. Triple super phosphate at 5000 mg P/kg decreased both Pb and Zn bioavailability in both soils. Rock phosphate at 5000 mg P/kg decreased Zn bioavailability, but not Pb bioavailability in both repository soils. Monocalcium phosphate and tricalcium phosphate at 5000 mg P/kg did not significantly decrease Pb or Zn bioavailability to earthworms in either repository soil. In order to optimize phosphorus amendments, additional phosphorus (up to 15,000 mg P/kg) and lowered pH were used in a series of tests. The combination of lowering the pH below 6.0 and increasing phosphorus concentrations caused complete mortality in all triple super phosphate amended soils and partial mortality in the highest rock phosphate amended soils. Results indicate that triple super phosphate and rock phosphate are viable soil amendments, but care should be taken when optimizing amendment quantity and pH so that adverse environmental effects are not a by-product. - Phosphorus form and pH were controlling factors in the effectiveness of phosphorus amendment in decreasing Pb and Zn bioavailability

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    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. - Highlights: ► Metal concentrations in caddisfly larvae can be calibrated against mayfly ecological responses. ► Cu, As, Zn and Pb concentrations in Hydropsyche siltalai were related to stream mayfly assemblages. ► Mayflies were sparse in high metal bioavailabilities, and abundant in low bioavailabilities. ► Joint heptageniid and ephemerellid mayfly abundance was the most sensitive response variable. ► Copper, arsenic and, in one catchment, lead were the primary stressors limiting mayfly abundance. - Accumulated metal concentrations in tolerant biomonitors can be used to detect and diagnose ecological impacts on freshwater stream benthos from metal stressors.

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

    International Nuclear Information System (INIS)

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

    2010-01-01

    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 0.02 M EDTA + 0.5 M 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.

  11. Lead and zinc bioavailability to Eisenia fetida after phosphorus amendment to repository soils

    Energy Technology Data Exchange (ETDEWEB)

    Ownby, David R. [Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University, Carbondale, IL 62901 (United States); Galvan, Kari A. [Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University, Carbondale, IL 62901 (United States); Lydy, Michael J. [Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University, Carbondale, IL 62901 (United States)]. E-mail: mlydy@siu.edu

    2005-07-15

    Four phosphorus forms were investigated as potential soil amendments to decrease the bioavailability of Pb and Zn in two repository soils to the earthworm, Eisenia fetida. Treatments were evaluated by examining differences in bioaccumulation factors between amended and non-amended soils. Triple super phosphate at 5000 mg P/kg decreased both Pb and Zn bioavailability in both soils. Rock phosphate at 5000 mg P/kg decreased Zn bioavailability, but not Pb bioavailability in both repository soils. Monocalcium phosphate and tricalcium phosphate at 5000 mg P/kg did not significantly decrease Pb or Zn bioavailability to earthworms in either repository soil. In order to optimize phosphorus amendments, additional phosphorus (up to 15,000 mg P/kg) and lowered pH were used in a series of tests. The combination of lowering the pH below 6.0 and increasing phosphorus concentrations caused complete mortality in all triple super phosphate amended soils and partial mortality in the highest rock phosphate amended soils. Results indicate that triple super phosphate and rock phosphate are viable soil amendments, but care should be taken when optimizing amendment quantity and pH so that adverse environmental effects are not a by-product. - Phosphorus form and pH were controlling factors in the effectiveness of phosphorus amendment in decreasing Pb and Zn bioavailability.

  12. Assessment of heavy metals bioavailability and toxicity toward Vibrio fischeri in sediment of the Huelva estuary.

    Science.gov (United States)

    Rosado, Daniel; Usero, José; Morillo, José

    2016-06-01

    Relationship between toxicity and bioavailable metals in sediments from the Huelva estuary and its littoral of influence was analyzed. Toxicity was assessed with Microtox® bioassay using a marine luminescent bacterium: Vibrio fischeri. Bioavailable metals were considered as both, acid extractable fraction of BCR procedure and the sum of exchangeable and bound to carbonates fractions of Tessier sequential extraction. A bioavailable metals index was calculated to integrate results in a single figure. Toxicity and bioavailable metals showed a similar pattern. Higher levels were found in the estuary than in the littoral (140 TU/g). In Huelva estuary, highest levels were found in the Tinto estuary (5725 TU/g), followed by the Odiel estuary (5100 TU/g) and the Padre Santo Canal (2500 TU/g). Results in this area were well over than those in nearby estuaries. Furthermore, they are similar to or even higher than those in other polluted sediments around the world. Bioavailable metal index showed a stronger correlation with acid extractable fraction of BCR (R(2) = 0.704) than that for the sum of exchangeable and bound to carbonates fractions of Tessier (R(2) = 0.661). These results suggest that bioavailable metals are an important source of sediment toxicity in the Huelva estuary and its littoral of influence, an area with one of the highest mortality risks of Spain. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Food processing strategies to enhance phenolic compounds bioaccessibility and bioavailability in plant-based foods.

    Science.gov (United States)

    Ribas-Agustí, Albert; Martín-Belloso, Olga; Soliva-Fortuny, Robert; Elez-Martínez, Pedro

    2017-06-13

    Phenolic compounds are important constituents of plant-based foods, as their presence is related to protective effects on health. To exert their biological activity, phenolic compounds must be released from the matrix during digestion in an absorbable form (bioaccessible) and finally absorbed and transferred to the bloodstream (bioavailable). Chemical structure and matrix interactions are some food-related factors that hamper phenolic compounds bioaccessibility and bioavailability, and that can be counteracted by food processing. It has been shown that food processing can induce chemical or physical modifications in food that enhance phenolic compounds bioaccessibility and bioavailability. These changes include: (i) chemical modifications into more bioaccessible and bioavailable forms; (ii) cleavage of covalent or hydrogen bonds or hydrophobic forces that attach phenolic compounds to matrix macromolecules; (iii) damaging microstructural barriers such as cell walls that impede the release from the matrix; and (iv) create microstructures that protect phenolic compounds until they are absorbed. Indeed, food processing can produce degradation of phenolic compounds, however, it is possible to counteract it by modulating the operating conditions in favor of increased bioaccessibility and bioavailability. This review compiles the current knowledge on the effects of processing on phenolic compounds bioaccessibility or bioavailability, while suggesting new guidelines in the search of optimal processing conditions as a step forward towards the design of healthier foods.

  14. Improved Dissolution and Oral Bioavailability of Celecoxib by a Dry Elixir System.

    Science.gov (United States)

    Cho, Kwan Hyung; Jee, Jun-Pil; Yang, Da A; Kim, Sung Tae; Kang, Dongjin; Kim, Dae-Young; Sim, Taeyong; Park, Sang Yeob; Kim, Kyeongsoon; Jang, Dong-Jin

    2018-02-01

    The purpose of this study was to develop and evaluate a dry elixir (DE) system for enhancing the dissolution rate and oral bioavailability of celecoxib. DE system has been used for improving solubility, oral bioavailability of poorly water-soluble drugs. The encapsulated drugs or solubilized drugs in the matrix are rapidly dissolved due to the co-solvent effect, resting in both an enhanced dissolution and bioavailability. DEs containing celecoxib were prepared by spray-drying method and characterized by morphology, drug/ethanol content, drug crystallinity, dissolution rate and oral bioavailability. The ethanol content and drug content in DE system could be easily altered by controlling the spraydrying conditions. The dissolution profile of celecoxib from DE proved to be much higher than that of celecoxib powder due to the nano-structured matrix, amorphous state and encapsulated ethanol. The bioavailability of celecoxib from DEs was compared with celecoxib powder alone and commercial product (Celebrex®) in rats. In particular, blood concentrations of celecoxib form DE formulation were much greater than those of native celecoxib and market product. The data demonstrate that the DE system could provide an useful solid dosage form to enhance the solubility, dissolution rate and oral bioavailability of celecoxib.

  15. 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. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. 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. © 2016 SETAC.

  17. Rapid and sensitive Nitrosomonas europaea biosensor assay for quantification of bioavailable ammonium sensu strictu in soil.

    Science.gov (United States)

    Nguyen, Minh Dong; Risgaard-Petersen, Nils; Sørensen, Jan; Brandt, Kristian K

    2011-02-01

    Knowledge on bioavailable ammonium sensu strictu (i.e., immediately available for cellular uptake) in soil is required to understand nutrient uptake processes in microorganisms and thus of vital importance for plant production. We here present a novel ammonium biosensor approach based on the lithoautotrophic ammonia-oxidizing bacterium Nitrosomonas europaea transformed with a luxAB sensor plasmid. Bioluminescence-based ammonium detection was achieved within 10 min with a quantification limit in liquid samples of ∼20 μM and a linear response range up to 400 μM. Biosensor and conventional chemical quantification of ammonium in soil solutions agreed well across a range of sample and assay conditions. The biosensor was subsequently applied for a solid phase-contact assay allowing for direct interaction of biosensor cells with soil particle-associated (i.e., exchangeable plus fixed) ammonium. The assay successfully quantified bioavailable ammonium even in unfertilized soil and demonstrated markedly higher ratios of bioavailable ammonium to water- or 2 M KCl-exchangeable ammonium in anoxic soil than in corresponding oxic soil. Particle-associated ammonium contributed by at least 74% and 93% of the total bioavailable pool in oxic and anoxic soil, respectively. The N. europaea biosensor should have broad relevance for environmental monitoring of bioavailable ammonium and processes depending on ammonium bioavailability.

  18. Transformation and bioavailability of metal oxide nanoparticles in aquatic and terrestrial environments. A review

    International Nuclear Information System (INIS)

    Amde, Meseret; Liu, Jing-fu; Tan, Zhi-Qiang; Bekana, Deribachew

    2017-01-01

    Metal oxide nanoparticles (MeO-NPs) are among the most consumed NPs and also have wide applications in various areas which increased their release into the environmental system. Aquatic (water and sediments) and terrestrial compartments are predicted to be the destination of the released MeO-NPs. In these compartments, the particles are subjected to various dynamic processes such as physical, chemical and biological processes, and undergo transformations which drive them away from their pristine state. These transformation pathways can have strong implications for the fate, transport, persistence, bioavailability and toxic-effects of the NPs. In this critical review, we provide the state-of-the-knowledge on the transformation processes and bioavailability of MeO-NPs in the environment, which is the topic of interest to researchers. We also recommend future research directions in the area which will support future risk assessments by enhancing our knowledge of the transformation and bioavailability of MeO-NPs. - Highlights: • Current state-of-the-knowledge on the transformation and bioavailability of MeO-NPs in the environment has been provided. • Effects of MeO-NPs behavior on their transformations have been reviewed. • Role of the transformation processes on bioavailability of the NPs have been discussed. • Future research directions required to fill the existing research gaps have been provided. - Transformations of MeO-NPs depend on nature of the NPs themselves and chemistry of the medium, and can significantly affect their fate, bioavailability and toxic-effects.

  19. 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.

  20. Relating metal bioavailability to risk assessment for aquatic species: Daliao River watershed, China

    International Nuclear Information System (INIS)

    Han, Shuping; Zhang, Ying; Masunaga, Shigeki; Zhou, Siyun; Naito, Wataru

    2014-01-01

    The spatial distribution of metal bioavailability (Ni, Cu, Zn, and Pb) was first evaluated within the waters of Daliao River watershed, using the diffusive gradient in thin films (DGT) and chemical equilibrium models. To assess potential risks associated with metal bioavailability, site-specific 95% protection levels (HC5), risk characterizations ratios (RCR) and ratios of DGT-labile/HC5 were derived, using species sensitivity distribution (SSD). The highest bioavailability values for metals were recorded in the main channel of the Daliao River, followed by the Taizi River. Dynamic concentrations predicted by WHAM 7.0 and NICA-Donnan for Cu and Zn agreed well with DGT results. The estuary of the Daliao River was found to have the highest risks related to Ni, Cu, and Zn. The number of sites at risk increased when considering the total toxicity of Ni, Cu, and Zn. - Highlights: • Spatial variation in metal bioavailability within Daliao River watershed was studied. • WHAM 7.0 and NICA-Donnan examined the differences in predicting metal speciation. • Bioavailability values of metals were highest in main channel of the Daliao River. • Site-specific 95% protection levels (HC5)/risk variations were assessed using SSD. • Maximum risks from Ni, Cu, and Zn occurred in the estuary of the Daliao River. - The highest bioavailability values and the highest risks of metals were found in the estuary of the Daliao River

  1. Incorporation of metal bioavailability into regulatory frameworks-metal exposure in water and sediment

    Energy Technology Data Exchange (ETDEWEB)

    Ahlf, Wolfgang [Inst. of Environmental Tech. and Energy Economics, TUHH, Hamburg (Germany); Drost, Wiebke [Umweltpruefung Chemikalien IV, Umweltbundesamt, Dessau (Germany); Heise, Susanne [Dept. of Life Sciences, HAW, Hamburg (Germany)

    2009-10-15

    Background, aim, and scope The cause for this position paper is the impression that risk assessors consider primarily the concentration of free metal ions dissolved in solution controlling metal bioavailability in aquatic systems. Aiming at a more realistic risk assessment of metals, bioavailability has to be discussed under the scope of main uptake routes of metals to organisms. Materials and methods On the basis of a review on the literature relating to bioavailability approaches, this work discusses the incorporation of metal bioavailability into the risk assessment of metals in the context of metal exposure. Results The biotic ligand model (BLM) and the concept of sulfide bound metals described by the ratio of simultaneously extracted metals and acid volatile sulfide concept (AVS) have been developed to consider the bioavailability of metals. Both approaches assume that the free ion concentration is the most relevant exposure pathway. However, apart from geochemical conditions, which control free metal concentration, bioavailability is additionally a result of contaminant/particle interaction and of organisms' activity. Asking for the relevant exposure pathways for inorganic metals to organisms, the compartments' water and sediment have been evaluated and also the importance of contaminated food. (orig.)

  2. 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.

  3. Enhanced ferrihydrite dissolution by a unicellular, planktonic cyanobacterium: a biological contribution to particulate iron bioavailability.

    Science.gov (United States)

    Kranzler, Chana; Kessler, Nivi; Keren, Nir; Shaked, Yeala

    2016-12-01

    Iron (Fe) bioavailability, as determined by its sources, sinks, solubility and speciation, places severe environmental constraints on microorganisms in aquatic environments. Cyanobacteria are a widespread group of aquatic, photosynthetic microorganisms with especially high iron requirements. While iron exists predominantly in particulate form, little is known about its bioavailability to cyanobacteria. Some cyanobacteria secrete iron solubilizing ligands called siderophores, yet many environmentally relevant strains do not have this ability. This work explores the bioavailability of amorphous synthetic Fe-oxides (ferrihydrite) to the non-siderophore producing, unicellular cyanobacterium, Synechocystis sp PCC 6803. Iron uptake assays with 55 ferrihydrite established dissolution as a critical prerequisite for iron transport. Dissolution assays with the iron binding ligand, desferrioxamine B, demonstrated that Synechocystis 6803 enhances ferrihydrite dissolution, exerting siderophore-independent biological influence on ferrihydrite bioavailability. Dissolution mechanisms were studied using a range of experimental conditions; both cell-particle physical proximity and cellular electron flow were shown to be important determinants of bio-dissolution by Synechocystis 6803. Finally, the effects of ferrihydrite stability on bio-dissolution rates and cell physiology were measured, integrating biological and chemical aspects of ferrihydrite bioavailability. Collectively, these findings demonstrate that Synechocystis 6803 actively dissolves ferrihydrite, highlighting a significant biological component to mineral phase iron bioavailability in aquatic environments. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Study on Characteristics of Soil Elements Bio-availability and Their Interrelationship in Black Soil Area of Jilin Province

    Science.gov (United States)

    Wang, D. Y.

    2015-12-01

    Abstract: Based on systematic field investigation and surface soil(0-20cm) sampling in the middle part of Jilin province where the soil type mainly consists of black soil and chernozem, soil total content and bio-available content of Fe, Fe, Ca, Mg, K, P, Cu, Zn, Ni, Cr, B, Cd, As were tested. This paper summarizes the geochemical characteristics of the soil elements and takes the ratio of bio-available content to total content as the bio-availability characteristic of each element in soil and studies the interrelationship between their geochemical characteristics of bio-availability by PCA and correlation analysis. Cd、Cr、Ni、Zn、P、Ca are selected out by PCA due to the similar impact under 4 principal components. And their correlation analysis results indicate: the correlation coefficients between heavy metal elements(Cr, Cd, Zn, Ni) bio-availability are significant positive, i.e., the same spatial variation trends are found between them in study area; the same relationships are also found between the bioavailability of P and 4 heavy metal elements (Cr, Cd, Zn, Ni), the promotion of the bioavailability of heavy metal elements goes with P; However, the correlation coefficients between heavy metal(Cr, Cd, Zn, Ni) bio-availability and Ca are mostly significant negative and the adverse spatial variation trends are found between them. The promotion of the bioavailability of heavy metal elements goes against Ca. Key words: soil geochemistry; soil heavy metals; elements interaction; bio-availability

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    Highlights: ► Demonstrates the nexus between sorption and bioavailability of As and Cd in variable-charge soils. ► Liming variable-charge soils increase negative charge, thereby decreasing Cd bioavailability. ► Ageing of As and Cd increases their immobilization, thereby decreasing bioavailability. ► Phosphate enhances desorption and phytoavailability of As from sheep dip soil. ► Metal(loid)s transfer to food chain can be managed by controlling sorption reactions. -- Abstract: 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Bolan, Nanthi, E-mail: Nanthi.Bolan@unisa.edu.au [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA (Australia); CRC for Contamination Assessment and Remediation in the Environment, University of South Australia, Mawson Lakes, SA (Australia); Mahimairaja, Santiago [Department of Environmental Science, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu (India); Kunhikrishnan, Anitha [Chemical Safety Division, Department of Agro-Food Safety, National Academy of Agricultural Science, Suwon-si, Gyeonggi-do 441-707 (Korea, Republic of); Naidu, Ravi [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA (Australia); CRC for Contamination Assessment and Remediation in the Environment, University of South Australia, Mawson Lakes, SA (Australia)

    2013-10-15

    Highlights: ► Demonstrates the nexus between sorption and bioavailability of As and Cd in variable-charge soils. ► Liming variable-charge soils increase negative charge, thereby decreasing Cd bioavailability. ► Ageing of As and Cd increases their immobilization, thereby decreasing bioavailability. ► Phosphate enhances desorption and phytoavailability of As from sheep dip soil. ► Metal(loid)s transfer to food chain can be managed by controlling sorption reactions. -- Abstract: 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

  7. Effect of Photochemical Transformation on Dissolved Organic Carbon Concentration and Bioavailability from Watersheds with Varying Landcover

    Science.gov (United States)

    Vermilyea, A.; Sanders, A.; Vazquez, E.

    2017-12-01

    The transformation of freshwater dissolved organic carbon (DOC) can have important implications for water quality, aquatic ecosystem health, and our climate. DOC is an important nutrient for heterotrophic microorganisms near the base of the aquatic food chain and the extent of conversion of DOC to CO2 is a critical piece of the global carbon cycle. Photochemical pathways have the potential to transform recalcitrant DOC into more labile forms that can then be converted to smaller DOC molecules and eventually be completely mineralized to CO2. This may lead to a DOC pool with different bioavailability depending on the structural composition of the original DOC pool and the mechanistic pathways undergone during transformation. This study aimed to measure the changes in DOC concentration and bioavailability due solely to photochemical processes in three watersheds of northern Vermont, USA that have varied land cover, land use (LCLU) attributes. Our hypothesis was that photochemical transformations will lead to (1) an overall loss of DOC due to mineralization to CO2 and (2) a relative increase in the bioavailable fraction of DOC. Additionally, the influence of LCLU and base flow versus storm flow on both mineralization rates and changes in DOC bioavailability was investigated. Irradiation of filtered samples in quartz vessels under sunlight led to small changes in DOC concentration over time, but significant changes in DOC bioavailability. In general, fluorescence excitation-emission matrices (EEMs) showed a shift from an initially more humic-like DOC pool, to a more protein-like (bioavailable) DOC pool. Specific UV index (SUVA) along with bioavailable DOC (BDOC) incubations were also used to characterize DOC and its bioavailability. There were only small differences in the DOC transformation that took place among sites, possibly due to only small differences in the initial bioavailability and fluorescent properties between water samples. Photochemical transformation

  8. Bioavailability enhanced rhizosphere remediation of petroleum hydrocarbon contaminated soil

    International Nuclear Information System (INIS)

    Marchenko, A.; Vorobyov, A.; Zharikov, G.; Ermolenko, Z.; Dyadishchev, N.; Borovick, R.; Sokolov, M.; Ortega-Calvo, J.J.

    2005-01-01

    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

  9. 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

  10. 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.

  11. 226Ra bioavailability of plants at urgeirica uranium mill tailings

    International Nuclear Information System (INIS)

    Madruga, M.J.; Brogueira, A.

    2002-01-01

    Large amounts of solid wastes (tailings) resulting from the exploitation and treatment of uranium ore at the Urgeirica mine (north of Portugal) have been accumulated in dams (tailing ponds). To reduce the dispersion of natural radionuclides into the environment some dams were revegetated with eucalyptus (Eucalyptus globolus) and pines (Pinus pinea). Besides, some shrubs (Cytisus s.p.) are growing at some of the dams. The objective of this study is to determine the 226 Ra bioavailability from uranium mill tailings through the quantification of the total and available fraction of radium in the solid wastes and to estimate its transfer to the plants growing on the tailing piles. Plants and solid waste samples were randomly collected at dams. Activity concentration of 226 Ra in plants (aerial part and roots) and solid wastes were measured by gamma spectrometry. The exchangeable fraction of radium in solid wastes was quantified using one single step extraction with 1 mol dm -3 ammonium acetate (pH=7) or 1 mol dm -3 calcium chloride solutions. The results obtained for the 226 Ra uptake by plants show that 226 Ra concentration ratios for eucalyptus and pines decrease at low 226 Ra concentration in the solid wastes and appear relatively constant at higher radium concentrations. For shrubs, the concentration ratios increase at higher 226 Ra solid waste concentrations approaching a saturation value. Percentage values of 16.0±8.3 and 12.9±8.9, for the fraction of radium extracted from the solid wastes, using 1 mol dm -3 ammonium acetate or calcium chloride solutions respectively, were obtained. The 226 Ra concentration ratios determined on the basis of exchangeable radium are one order of magnitude higher than those based on total radium. It can be concluded that, within the standard error values, more consistent 226 Ra concentration ratios were obtained when calculated on the basis of available radium than when total radium was considered, for all the dams. (author)

  12. 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.

  13. 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)

  14. Metal bioavailability in ecological risk assessment of freshwater ecosystems: From science to environmental management.

    Science.gov (United States)

    Väänänen, Kristiina; Leppänen, Matti T; Chen, XuePing; Akkanen, Jarkko

    2018-01-01

    Metal contamination in freshwater ecosystems is a global issue and metal discharges to aquatic environments are monitored in order to protect aquatic life and human health. Bioavailability is an important factor determining metal toxicity. In aquatic systems, metal bioavailability depends on local water and sediment characteristics, and therefore, the risks are site-specific. Environmental quality standards (EQS) are used to manage the risks of metals in aquatic environments. In the simplest form of EQSs, total concentrations of metals in water or sediment are compared against pre-set acceptable threshold levels. Now, however, the environmental administration bodies have stated the need to incorporate metal bioavailability assessment tools into environmental regulation. Scientific advances have been made in metal bioavailability assessment, including passive samplers and computational models, such as biotic ligand models (BLM). However, the cutting-edge methods tend to be too elaborate or laborious for standard environmental monitoring. We review the commonly used metal bioavailability assessment methods and introduce the latest scientific advances that might be applied to environmental management in the future. We present the current practices in environmental management in North America, Europe and China, highlighting the good practices and the needs for improvement. Environmental management has met these new challenges with varying degrees of success: the USA has implemented site-specific environmental risk assessment for water and sediment phases, and they have already implemented metal mixture toxicity evaluation. The European Union is promoting the use of bioavailability and BLMs in ecological risk assessment (ERA), but metal mixture toxicity and sediment phase are still mostly neglected. China has regulation only for total concentrations of metals in surface water. We conclude that there is a need for (1) Advanced and up-to-date guidelines and legislation

  15. Artificial neural network model for predicting the bioavailability of tacrolimus in patients with renal transplantation

    Science.gov (United States)

    Thishya, Kalluri; Vattam, Kiran Kumar; Naushad, Shaik Mohammad; Raju, Shree Bhushan

    2018-01-01

    The objective of the current study was to explore the role of ABCB1 and CYP3A5 genetic polymorphisms in predicting the bioavailability of tacrolimus and the risk for post-transplant diabetes. Artificial neural network (ANN) and logistic regression (LR) models were used to predict the bioavailability of tacrolimus and risk for post-transplant diabetes, respectively. The five-fold cross-validation of ANN model showed good correlation with the experimental data of bioavailability (r2 = 0.93–0.96). Younger age, male gender, optimal body mass index were shown to exhibit lower bioavailability of tacrolimus. ABCB1 1236 C>T and 2677G>T/A showed inverse association while CYP3A5*3 showed a positive association with the bioavailability of tacrolimus. Gender bias was observed in the association with ABCB1 3435 C>T polymorphism. CYP3A5*3 was shown to interact synergistically in increasing the bioavailability in combination with ABCB1 1236 TT or 2677GG genotypes. LR model showed an independent association of ABCB1 2677 G>T/A with post transplant diabetes (OR: 4.83, 95% CI: 1.22–19.03). Multifactor dimensionality reduction analysis (MDR) revealed that synergistic interactions between CYP3A5*3 and ABCB1 2677 G>T/A as the determinants of risk for post-transplant diabetes. To conclude, the ANN and MDR models explore both individual and synergistic effects of variables in modulating the bioavailability of tacrolimus and risk for post-transplant diabetes. PMID:29621269

  16. Total sulfane sulfur bioavailability reflects ethnic and gender disparities in cardiovascular disease

    Directory of Open Access Journals (Sweden)

    Saurabh Rajpal

    2018-05-01

    Full Text Available Hydrogen sulfide (H2S has emerged as an important physiological and pathophysiological signaling molecule in the cardiovascular system influencing vascular tone, cytoprotective responses, redox reactions, vascular adaptation, and mitochondrial respiration. However, bioavailable levels of H2S in its various biochemical metabolite forms during clinical cardiovascular disease remain poorly understood. We performed a case-controlled study to quantify and compare the bioavailability of various biochemical forms of H2S in patients with and without cardiovascular disease (CVD. In our study, we used the reverse-phase high performance liquid chromatography monobromobimane assay to analytically measure bioavailable pools of H2S. Single nucleotide polymorphisms (SNPs were also identified using DNA Pyrosequencing. We found that plasma acid labile sulfide levels were significantly reduced in Caucasian females with CVD compared with those without the disease. Conversely, plasma bound sulfane sulfur levels were significantly reduced in Caucasian males with CVD compared with those without the disease. Surprisingly, gender differences of H2S bioavailability were not observed in African Americans, although H2S bioavailability was significantly lower overall in this ethnic group compared to Caucasians. We also performed SNP analysis of H2S synthesizing enzymes and found a significant increase in cystathionine gamma-lyase (CTH 1364 G-T allele frequency in patients with CVD compared to controls. Lastly, plasma H2S bioavailability was found to be predictive for cardiovascular disease in Caucasian subjects as determined by receiver operator characteristic analysis. These findings reveal that plasma H2S bioavailability could be considered a biomarker for CVD in an ethnic and gender manner. Cystathionine gamma-lyase 1346 G-T SNP might also contribute to the risk of cardiovascular disease development.

  17. Total sulfane sulfur bioavailability reflects ethnic and gender disparities in cardiovascular disease.

    Science.gov (United States)

    Rajpal, Saurabh; Katikaneni, Pavan; Deshotels, Matthew; Pardue, Sibile; Glawe, John; Shen, Xinggui; Akkus, Nuri; Modi, Kalgi; Bhandari, Ruchi; Dominic, Paari; Reddy, Pratap; Kolluru, Gopi K; Kevil, Christopher G

    2018-05-01

    Hydrogen sulfide (H 2 S) has emerged as an important physiological and pathophysiological signaling molecule in the cardiovascular system influencing vascular tone, cytoprotective responses, redox reactions, vascular adaptation, and mitochondrial respiration. However, bioavailable levels of H 2 S in its various biochemical metabolite forms during clinical cardiovascular disease remain poorly understood. We performed a case-controlled study to quantify and compare the bioavailability of various biochemical forms of H 2 S in patients with and without cardiovascular disease (CVD). In our study, we used the reverse-phase high performance liquid chromatography monobromobimane assay to analytically measure bioavailable pools of H 2 S. Single nucleotide polymorphisms (SNPs) were also identified using DNA Pyrosequencing. We found that plasma acid labile sulfide levels were significantly reduced in Caucasian females with CVD compared with those without the disease. Conversely, plasma bound sulfane sulfur levels were significantly reduced in Caucasian males with CVD compared with those without the disease. Surprisingly, gender differences of H 2 S bioavailability were not observed in African Americans, although H 2 S bioavailability was significantly lower overall in this ethnic group compared to Caucasians. We also performed SNP analysis of H 2 S synthesizing enzymes and found a significant increase in cystathionine gamma-lyase (CTH) 1364 G-T allele frequency in patients with CVD compared to controls. Lastly, plasma H 2 S bioavailability was found to be predictive for cardiovascular disease in Caucasian subjects as determined by receiver operator characteristic analysis. These findings reveal that plasma H 2 S bioavailability could be considered a biomarker for CVD in an ethnic and gender manner. Cystathionine gamma-lyase 1346 G-T SNP might also contribute to the risk of cardiovascular disease development. Copyright © 2018 The Authors. Published by Elsevier B.V. All

  18. 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.

  19. 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.

  20. Enhancement of Solubility, Dissolution rate and Bioavailability of Efavirenz by Cyclodextrins and Solutol HS15 - A Factorial Study

    OpenAIRE

    R. Yogananda; K. P. R. Chowdary

    2013-01-01

    Efavirenz widely prescribed anti-retroviral drug belongs to class II BCS and exhibit low and variable oral bioavailability due to its poor aqueous solubility and it requires enhancement in solubility and dissolution rate for increasing its oral bioavailability. The objective of the present investigation is to enhance the solubility, dissolution rate and bioavailability of efavirenz by the use of cyclodextrins (%CD and HP%CD) and surfactant, Solutol HS15. The individual main effects and combin...

  1. Bioavailability of Carbon Nanomaterial-Adsorbed Polycyclic Aromatic Hydrocarbons to Pimphales promelas: Influence of Adsorbate Molecular Size and Configuration.

    Science.gov (United States)

    Linard, Erica N; Apul, Onur G; Karanfil, Tanju; van den Hurk, Peter; Klaine, Stephen J

    2017-08-15

    Despite carbon nanomaterials' (CNMs) potential to alter the bioavailability of adsorbed contaminants, information characterizing the relationship between adsorption behavior and bioavailability of CNM-adsorbed contaminants is still limited. To investigate the influence of CNM morphology and organic contaminant (OC) physicochemical properties on this relationship, adsorption isotherms were generated for a suite of polycyclic aromatic hydrocarbons (PAHs) on multiwalled carbon nanotubes (MWCNTs) and exfoliated graphene (GN) in conjunction with determining the bioavailability of the adsorbed PAHs to Pimphales promelas using bile analysis via fluorescence spectroscopy. Although it appeared that GN adsorbed PAHs indiscriminately compared to MWCNTs, the subsequent bioavailability of GN-adsorbed PAHs was more sensitive to PAH morphology than MWCNTs. GN was effective at reducing bioavailability of linear PAHs by ∼70%, but had little impact on angular PAHs. MWCNTs were sensitive to molecular size, where bioavailability of two-ringed naphthalene was reduced by ∼80%, while bioavailability of the larger PAHs was reduced by less than 50%. Furthermore, the reduction in bioavailability of CNM-adsorbed PAHs was negatively correlated with the amount of CNM surface area covered by the adsorbed-PAHs. This study shows that the variability in bioavailability of CNM-adsorbed PAHs is largely driven by PAH size, configuration and surface area coverage.

  2. In vivo efficacy and bioavailability of lumefantrine: Evaluating the application of Pheroid technology.

    Science.gov (United States)

    du Plessis, Lissinda H; Govender, Katya; Denti, Paolo; Wiesner, Lubbe

    2015-11-01

    The oral absorption of compounds with low aqueous solubility, such as lumefantrine, is typically limited by the dissolution rate in the gastro-intestinal tract, resulting in erratic absorption and highly variable bioavailability. In previous studies we reported on the ability of Pheroid vesicles to improve the bioavailability of poorly soluble drugs. In the present study a Pro-Pheroid formulation, a modification of the previous formulation, was applied to improve the solubility of lumefantrine after oral administration and compared to lumefantrine in DMSO:water (1:9 v/v) solution (reference solution). A bioavailability study of lumefantrine was conducted in a mouse model in fed and fasted states. When using the reference solution, the bioavailability of the lumefantrine heavily depended on food intake, resulting in a 2.7 times higher bioavailability in the fed state when compared to the fasted state. It also showed large between-subject variability. When formulated using Pro-Pheroid, the bioavailability of lumefantrine was 3.5 times higher as compared to lumefantrine in the reference solution and fasting state. Pro-Pheroid also dramatically reduced the effects of food intake and the between-subject variability for bioavailability observed with the reference. In vivo antimalarial efficacy was also evaluated with lumefantrine formulated using Pro-Pheroid technology compared to the reference solution. The results indicated that lumefantrine in Pro-Pheroid formulation exhibited improved antimalarial activity in vitro by 46.8%, when compared to the reference. The results of the Peters' 4-day suppressive test indicated no significant difference in the efficacy or mean survival time of the mice in the Pro-Pheroid formulation and reference test groups when compared to the positive control, chloroquine. These findings suggest that using the Pro-Pheroid formulation improves the bioavailability of lumefantrine, eliminates the food effect associated with lumefantrine as well

  3. 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

  4. Development and evaluation of a novel microemulsion formulation of elacridar to improve its bioavailability

    Science.gov (United States)

    Sane, Ramola; Mittapalli, Rajendar K.; Elmquist, William F.

    2014-01-01

    The study objective was to develop a formulation of elacridar to overcome its dissolution-rate limited bioavailability. Elacridar is a P-gp and BCRP inhibitor that has been used to improve the brain distribution of drugs that are substrates of P-gp and BCRP. The chronic use of elacridar is restricted due to poor solubility leading to poor oral bioavailability. A microemulsion formulation using Cremophor EL, Carbitol and Captex 355 (6:3:1) was developed. The elacridar microemulsion was effective in the inhibition of P-gp and Bcrp in MDCKII-transfected cells. FVBn mice were used to determine the bioavailability of elacridar after a 10 mg/kg dose of elacridar in the microemulsion, intraperitoneally and orally; and the absolute bioavailability was determined to be 1.3 and 0.47, respectively. Co-administration of elacridar microemulsion intraperitoneally with oral erlotinib in FVBn mice improved the erlotinib brain penetration three-fold. The current study shows that a microemulsion formulation of elacridar is effective in improving the bioavailability of elacridar and is an effective inhibitor of P-gp and Bcrp; in-vitro and in-vivo. It offers an alternative to the suspension and allows a decrease in the dose required to achieve a significant inhibitory effect at the blood-brain barrier. PMID:23334925

  5. Boosting the bioavailability of hydrophobic nutrients, vitamins, and nutraceuticals in natural products using excipient emulsions.

    Science.gov (United States)

    McClements, David Julian; Saliva-Trujillo, Laura; Zhang, Ruojie; Zhang, Zipei; Zou, Liqiang; Yao, Mingfei; Xiao, Hang

    2016-10-01

    Many highly hydrophobic bioactives, such as non-polar nutrients, nutraceuticals, and vitamins, have a relatively low or variable oral bioavailability. The poor bioavailability profile of these bioactives may be due to limited bioaccessibility, poor absorption, and/or chemical transformation within the gastrointestinal tract (GIT). The bioavailability of hydrophobic bioactives can be improved using specially designed oil-in-water emulsions consisting of lipid droplets dispersed within an aqueous phase. The bioactives may be isolated from their natural environment and then incorporated into the lipid phase of emulsion-based delivery systems. Alternatively, the bioactives may be left in their natural environment (e.g., fruits or vegetables), and then ingested with emulsion-based excipient systems. An excipient emulsion may have no inherent health benefits itself, but it boosts the biological activity of bioactive ingredients co-ingested with it by altering their bioaccessibility, absorption, and/or chemical transformation. This review discusses the design and fabrication of excipient emulsions, and gives some examples of recent research that demonstrates their potential efficacy for improving the bioavailability of hydrophobic bioactives. The concept of excipient emulsions could be used to formulate emulsion-based food products (such as excipient sauces, dressings, dips, creams, or yogurts) specifically designed to increase the bioavailability of bioactive agents in natural foods, such as fruits and vegetables. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Octacosanol educes physico-chemical attributes, release and bioavailability as modified nanocrystals.

    Science.gov (United States)

    Sen Gupta, Surashree; Ghosh, Mahua

    2017-10-01

    Octacosanol is a lesser known nutraceutical with the potential for treatment of several inflammatory diseases, high cholesterol, Parkinson's symptoms and tumour growth along with the capacity to improve athletic performance. But its lipophilicity and large structure inhibits extended solubility in water resulting in poor absorption and a low bioavailability. In the present work, sodium salt of octacosyl sulfate was synthesized. It displayed improved water solubility. Its nanocrystals, synthesized by means of nanoprecipitation technique, enhanced diffusion velocity, antioxidant capacity, shelf-life, penetrability and bioavailability. Particle size of the nanocrystals ranged between 197 and 220nm. Both modified octacosanol and its nanocrystals displayed maximum lipid peroxidation activities at a concentration 1000ppm, but nanocrystals demonstrated higher prevention. From freeze-thaw cycles it was evident that normal octacosanol crystals were far more prone to temperature variations than the nanocrystals. A pronounced increase in release/diffusion rate and bioavailability was observed for the nanocrystals of the modified octacosanol. In vitro release kinetics, bioavailability and bioequivalence were studied. Relative bioavailability for gastric passage and pancreatic passage of nanocrystals was 2.58 times and 1.81 times that of normal crystals respectively. Furthermore the nanocrystals displayed a superior in vitro release rate, while following a non-Fickian mode. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Extractability and bioavailability of Pb and As in historically contaminated orchard soil: Effects of compost amendments

    International Nuclear Information System (INIS)

    Fleming, Margaret; Tai, Yiping; Zhuang, Ping; McBride, Murray B.

    2013-01-01

    The availability of Pb and As in an historically contaminated orchard soil, after amendment with compost and aging in the field, was determined by single-step chemical extraction with 1.0 M ammonium acetate at pH 4.8, sequential extraction using the modified BCR test, and a redworm bioassay in the laboratory. The efficiency of soil Pb extraction by ammonium acetate was greater at higher total soil Pb but was reduced by compost amendment. Conversely, the extraction efficiency of total soil As increased with compost amendment, but was not sensitive to total soil As. The redworm bioassay indicated Pb (but not As) bioavailability to be reduced by soil amendment with compost, a result consistent with the ammonium acetate extraction test but not reflected in modified BCR test. Electron microprobe studies of the orchard soil revealed Pb and As to be spatially associated in discrete particles along with phosphorus and iron. -- Highlights: ► Soil Pb and As in an old orchard were concentrated in discrete particles. ► Compost amendment of contaminated soil reduced Pb bioavailability. ► Compost amendment of contaminated soil did not reduce As bioavailability. ► Ammonium acetate extraction test reflected bioavailability of soil Pb and As. -- Remediating metal-contaminated orchard soils with compost reduced lead bioavailability but had little effect on arsenic

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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. (paper)

  9. Higher iron bioavailability of a human-like collagen iron complex.

    Science.gov (United States)

    Zhu, Chenhui; Yang, Fan; Fan, Daidi; Wang, Ya; Yu, Yuanyuan

    2017-07-01

    Iron deficiency remains a public health problem around the world due to low iron intake and/or bioavailability. FeSO 4 , ferrous succinate, and ferrous glycinate chelate are rich in iron but have poor bioavailability. To solve the problem of iron deficiency, following previous research studies, a thiolated human-like collagen-ironcomplex supplement with a high iron content was prepared in an anaerobic workstation. In addition, cell viability tests were evaluated after conducting an MTT assay, and a quantitative analysis of the thiolated human-like collagen-iron digesta samples was performed using the SDS-PAGE method coupled with gel filtration chromatography. The iron bioavailability was assessed using Caco-2 cell monolayers and iron-deficiency anemia mice models. The results showed that (1) one mole of thiolated human-like collagen-iron possessed approximately 35.34 moles of iron; (2) thiolated human-like collagen-iron did not exhibit cytotoxity and (3) thiolated human-like collagen- iron digesta samples had higher bioavailability than other iron supplements, including FeSO 4 , ferrous succinate, ferrous glycine chelate and thiolated human-like collagen-Fe iron. Finally, the iron bioavailability was significantly enhanced by vitamin C. These results indicated that thiolated human-like collagen-iron is a promising iron supplement for use in the future.

  10. Oral bioavailability enhancement and hepatoprotective effects of thymoquinone by self-nanoemulsifying drug delivery system.

    Science.gov (United States)

    Kalam, Mohd Abul; Raish, Mohammad; Ahmed, Ajaz; Alkharfy, Khalid M; Mohsin, Kazi; Alshamsan, Aws; Al-Jenoobi, Fahad I; Al-Mohizea, Abdullah M; Shakeel, Faiyaz

    2017-07-01

    Thymoquinone (TQ) is a poorly water soluble bioactive compound which shows poor oral bioavailability upon oral administration. Due to poor aqueous solubility and bioavailability of TQ, various self-nanoemulsifying drug delivery systems (SNEDDS) of TQ were developed and evaluated for enhancement of its hepatoprotective effects and oral bioavailability. Hepatoprotective and pharmacokinetic studies of TQ suspension and TQ-SNEDDS were carried out in rat models. Different SNEDDS formulations of TQ were developed and thermodynamically stable TQ-SNEDDS were characterized for physicochemical parameters and evaluated for drug release studies via dialysis membrane. Optimized SNEDDS formulation of TQ was selected for further evaluation of in vivo evaluation. In vivo hepatoprotective investigations showed significant hepatoprotective effects for optimized TQ-SNEDDS in comparison with TQ suspension. The oral administration of optimized SNEDDS showed significant improvement in in vivo absorption of TQ in comparison with TQ suspension. The relatively bioavailability of TQ was enhanced 3.87-fold by optimized SNEDDS in comparison with TQ suspension. The results of this research work indicated the potential of SNEDDS in enhancing relative bioavailability and therapeutic effects of natural bioactive compounds such as TQ. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Emerging role of nanocarriers to increase the solubility and bioavailability of curcumin.

    Science.gov (United States)

    Mohanty, Chandana; Das, Manasi; Sahoo, Sanjeeb K

    2012-11-01

    Curcumin is a safe, affordable and natural bioactive molecule of turmeric (Curcuma longa). It has gained considerable attention in recent years for its multiple pharmacological activities. However, its optimum pharmaceutical potential has been limited by its lack of aqueous solubility and poor bioavailability. To mitigate the above limitations, recently various nanostructured water-soluble delivery systems were developed to increase the solubility and bioavailability of curcumin. Major reasons contributing to the low bioavailability of curcumin appear to be owing to its poor solubility, low absorption, rapid metabolism and rapid systemic elimination. The present review summarizes the strategies using curcumin in various nanocarrier delivery systems to overcome poor solubility and inconsistent bioavailability of curcumin and describes the current status and challenges for the future. The development of various drug delivery systems to deliver curcumin will certainly provide a step up towards augmenting the therapeutic activity of curcumin thereby increasing the solubility and bioavailability of curcumin. However, the future of such delivery technology will be highly dependent on the development of safe, non-toxic and non-immunogenic nanocarriers.

  12. Timeline (Bioavailability) of Magnesium Compounds in Hours: Which Magnesium Compound Works Best?

    Science.gov (United States)

    Uysal, Nazan; Kizildag, Servet; Yuce, Zeynep; Guvendi, Guven; Kandis, Sevim; Koc, Basar; Karakilic, Aslı; Camsari, Ulas M; Ates, Mehmet

    2018-04-21

    Magnesium is an element of great importance functioning because of its association with many cellular physiological functions. The magnesium content of foods is gradually decreasing due to food processing, and magnesium supplementation for healthy living has become increasingly popular. However, data is very limited on the bioavailability of various magnesium preparations. The aim of this study is to investigate the bioavailability of five different magnesium compounds (magnesium sulfate, magnesium oxide, magnesium acetyl taurate, magnesium citrate, and magnesium malate) in different tissues. Following a single dose 400 mg/70 kg magnesium administration to Sprague Dawley rats, bioavailability was evaluated by examining time-dependent absorption, tissue penetration, and the effects on the behavior of the animals. Pharmacokinetically, the area under the curve calculation is highest in the magnesium malate. The magnesium acetyl taurate was found to have the second highest area under the curve calculation. Magnesium acetyl taurate was rapidly absorbed, able to pass through to the brain easily, had the highest tissue concentration level in the brain, and was found to be associated with decreased anxiety indicators. Magnesium malate levels remained high for an extended period of time in the serum. The commonly prescribed dietary supplements magnesium oxide and magnesium citrate had the lowest bioavailability when compared to our control group. More research is needed to investigate the bioavailability of magnesium malate and acetyl taurate compounds and their effects in specific tissues and on behavior.

  13. Association between serum levels of bioavailable vitamin D and negative symptoms in first-episode psychosis.

    Science.gov (United States)

    Yee, Jie Yin; See, Yuen Mei; Abdul Rashid, Nur Amirah; Neelamekam, Sasi; Lee, Jimmy

    2016-09-30

    Total vitamin D levels had been commonly reported to be lowered in patients with chronic psychotic illnesses in countries from the higher latitudes. However, studies on patients with first episode psychosis (FEP) are limited. In this study we investigated serum concentrations of total and bioavailable vitamin D levels in FEP patients compared to healthy controls and the association between symptom severity and vitamin D components. A total of 31 FEP patients and 31 healthy controls were recruited from Institute of Mental Health, Singapore. FEP patients were identified using Structured Clinical Interview for DSM-IV Axis I disorders (SCID-1) and severity symptoms were assessed using the positive and negative syndrome scale (PANSS). Sera from participants were analyzed for total vitamin D, vitamin D-binding protein (DBP) and bioavailable vitamin D. Linear regressions were performed to examine the associations between serum total and bioavailable vitamin D and the PANSS subscales. Current study noted a significantly lower bioavailable vitamin D was in the FEP group and an association between bioavailable vitamin D and negative symptoms in FEP patients in a population with a consistent supply of sun exposure throughout the year. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  14. 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.

  15. Enrichment and Bioavailability of Trace Elements in Soil in Vicinity of Railways in Japan.

    Science.gov (United States)

    Wang, Zhen; Watanabe, Izumi; Ozaki, Hirozaku; Zhang, Jianqiang

    2018-01-01

    This study focuses on the concentrations, distribution, pollution levels, and bioavailability of 12 trace elements in soils along 6 different railways in Japan. Three diesel powered railways and three electricity powered railways were chosen as target. Surface soils (railways for analysis. Digestion and extraction were performed before concentration and bioavailability analysis. Enrichment factor was applied to investigate contamination levels of selected elements. The mean concentrations of Cr, Co, Ni, Cu, Zn, Sn, and Pb in soil samples were higher than soil background value in Japan. Concentrations of trace elements in soils along different railway had different characteristics. Horizontal distribution of Cu, Zn, Cd, Sn, and Pb in soil samples showed obviously downtrend with distance along railways with high frequency. Concentrations of V, Mn, Fe, and Co were higher in soils along railways which pass through city center. According to principal component analysis and cluster analysis, concentrations of Cu, Zn, Sn, and Pb could be considered as the indicators of soil contamination level along electricity powered trains, whereas indicators along diesel powered trains were not clear. Enrichment factor analysis proved that operation of freight trains had impact on pollution level of Cr, Ni, and Cd. Bioavailability of Mn, Co, Zn, and Cd in soil along electricity-powered railways were higher, and bioavailability of Pb in railways located in countryside was lower. Thus, enrichment and bioavailability of trace elements can be indicators of railway-originated trace elements pollution in soil.

  16. 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.

  17. A Helix-Stabilizing Linker Improves Subcutaneous Bioavailability of a Helical Peptide Independent of Linker Lipophilicity

    Science.gov (United States)

    Zhang, Liang; Navaratna, Tejas; Thurber, Greg M.

    2016-01-01

    Stabilized peptides address several limitations to peptide-based imaging agents and therapeutics such as poor stability and low affinity due to conformational flexibility. There is also active research in developing these compounds for intracellular drug targeting, and significant efforts have been invested to determine the effects of helix stabilization on intracellular delivery. However, much less is known about the impact on other pharmacokinetic parameters such as plasma clearance and bioavailability. We investigated the effect of different fluorescent helix-stabilizing linkers with varying lipophilicity on subcutaneous (SC) bioavailability using the glucagon-like peptide-1 (GLP-1) receptor ligand exendin as a model system. The stabilized peptides showed significantly higher protease resistance and increased bioavailability independent of linker hydrophilicity, and all subcutaneously delivered conjugates were able to successfully target the islets of Langerhans with high specificity. The lipophilic peptide variants had slower absorption and plasma clearance than their respective hydrophilic conjugates, and the absolute bioavailability was also lower likely due to the longer residence times in the skin. The ease and efficiency of double-click helix stabilization chemistries is a useful tool for increasing the bioavailability of peptide therapeutics, many of which suffer from rapid in vivo protease degradation. Helix stabilization using linkers of varying lipophilicity can further control SC absorption and clearance rates to customize plasma pharmacokinetics. PMID:27327034

  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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Creatinine-based non-phospholipid vesicular carrier for improved oral bioavailability of Azithromycin.

    Science.gov (United States)

    Ullah, Shafi; Shah, Muhammad Raza; Shoaib, Mohammad; Imran, Muhammad; Shah, Syed Wadood Ali; Ali, Imdad; Ahmed, Farid

    2017-06-01

    Novel, safe, efficient and cost effective nano-carriers from renewable resources have got greater interest for enhancing solubility and bioavailability of hydrophobic dugs. This study reports the synthesis of a novel biocompatible non-phospholipid human metabolite "Creatinine" based niosomal delivery system for Azithromycin improved oral bioavailability. Synthesized surfactant was characterized through spectroscopic and spectrometric techniques and then the potential for niosomal vesicle formation was evaluated using Azithromycin as model drug. Drug loaded vesicles were characterized for size, polydispersity index (PDI), shape, drug encapsulation efficiency (EE), in vitro release and drug-excipient interaction using zetasizer, atomic force microscope (AFM), LC-MS/MS and FTIR. The biocompatibility of surfactant was investigated through cells cytotoxicity, blood hemolysis and acute toxicity. Azithromycin encapsulated in niosomes was investigated for in vivo bioavailability in rabbits. The vesicles were spherical with 247 ± 4.67 nm diameter hosting 73.29 ± 3.51% of the drug. Surfactant was nontoxic against cell cultures and caused 5.80 ± 0.51% hemolysis at 1000 µg/mL. It was also found safe in mice up to 2.5 g/kg body weight. Synthesized surfactant based niosomal vesicles revealed enhanced oral bioavailability of Azithromycin in rabbits. The results of the present study confirm that the novel surfactant is highly biocompatible and the niosomal vesicles can be efficiently used for improving the oral bioavailability of poor water soluble drugs.

  20. Biogeochemical controls of uranium bioavailability from the dissolved phase in natural freshwaters

    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.

  1. Simulation of Food Folate Digestion and Bioavailability of an Oxidation Product of 5-Methyltetrahydrofolate.

    Science.gov (United States)

    Ringling, Christiane; Rychlik, Michael

    2017-09-01

    Generating bioavailability data from in vivo studies is time-consuming and expensive. In vitro simulation can help to investigate factors influencing bioavailability or facilitate quantifying the impact of such factors. For folates, an efficient deconjugation of polyglutamates to the corresponding monoglutamates is crucial for bioavailability and highly dependent on the food matrix. Therefore, the bioaccessibility of folates of different foodstuffs was examined using a simulated digestion model with respect to folate stability and the efficiency of deconjugation. For realistic simulated deconjugation, porcine brush border membrane was used during the phase of the simulated digestion in the small intestine. For a better understanding of folate behaviour during digestion, single folate monoglutamates were also investigated with this in vitro digestion model. The results for bioaccessibility were compared with data from a human bioavailability study. They support the idea that both stability and deconjugation have an influence on bioaccessibility and thus on bioavailability. Tetrahydrofolate is probably lost completely or at least to a high extent and the stability of 5-methyltetrahydrofolate depends on the food matrix. Additionally, 5-methyltetrahydrofolate can be oxidised to a pyrazino-s-triazine (MeFox), whose absorption in the human intestinal tract was shown tentatively.

  2. Plants may alter competition by modifying nutrient bioavailability in rhizosphere: a modeling approach.

    Science.gov (United States)

    Raynaud, Xavier; Jaillard, Benoît; Leadley, Paul W

    2008-01-01

    Plants modify nutrient availability by releasing chemicals in the rhizosphere. This change in availability induced by roots (bioavailability) is known to improve nutrient uptake by individual plants releasing such compounds. Can this bioavailability alter plant competition for nutrients and under what conditions? To address these questions, we have developed a model of nutrient competition between plant species based on mechanistic descriptions of nutrient diffusion, plant exudation, and plant uptake. The model was parameterized using data of the effects of root citrate exudation on phosphorus availability. We performed a sensitivity analysis for key parameters to test the generality of these effects. Our simulations suggest the following. (1) Nutrient uptake depends on the number of roots when nutrients and exudates diffuse little, because individual roots are nearly independent in terms of nutrient supply. In this case, bioavailability profits only species with exudates. (2) Competition for nutrients depends on the spatial arrangement of roots when nutrients diffuse little but exudates diffuse widely. (3) Competition for nutrients depends on the nutrient uptake capacity of roots when nutrients and exudates diffuse widely. In this case, bioavailability profits all species. Mechanisms controlling competition for bioavailable nutrients appear to be diverse and strongly depend on soil, nutrient, and plant properties.

  3. Bioavailable 25(OHD but Not Total 25(OHD Is an Independent Determinant for Bone Mineral Density in Chinese Postmenopausal Women

    Directory of Open Access Journals (Sweden)

    Chenguang Li

    2017-02-01

    Full Text Available Total 25(OHD levels were determined to assess bone health in elderly populations; however, the bioavailability of 25(OHD is regulated by the albumin and vitamin D binding protein (DBP levels and DBP variations. Whether bioavailable 25(OHD level is a superior biomarker for vitamin D than total 25(OHD level regarding the BMD and the bone metabolism were not yet fully understood. With a community based cross-sectional study of 967 postmenopausal women, we found that the variant rs7041, but not rs4588, of DBP was significantly associated with the blood DBP level, which was positively correlated with the total 25(OHD level but negatively associated with bioavailable 25(OHD levels. Both total and bioavailable 25(OHD levels were significantly correlated with the BMD value in postmenopausal women; however, only the bioavailable 25(OHD level was an independent determinant of the BMD values when adjusted for age, body mass index and bone turnover biomarkers (OST and β-CTX. The bioavailable and total 25(OHD were negatively correlated with bone formation biomarkers (OST, PINP and ALP and PTH levels, while they were positively correlated with osteoprotegerin (OPG level; however, the bone resorption biomarker (β-CTX was not correlated with the 25(OHD levels. An increment of PTH level, along with reduced bioavailable 25(OHD levels, was evident when the bioavailable 25(OHD level was <5 ng/mL, which may be the optimal cutpoint for sufficient vitamin D in Chinese elderly women. The blood calcium, magnesium, ALP, TSH, FGF23, and phosphorus levels were not correlated with the total or the bioavailable 25(OHD levels. These results suggested that high bioavailable 25(OHD levels were correlated with reduced bone turnover processes and were a biomarker superior to total 25(OHD for vitamin D in assessing the risks of bone-related diseases. The results indicate that the bioavailable 25(OHD level should be determined in assessing the bone health.

  4. Enhancing the bioavailability of magnolol in rabbits using melting solid dispersion with polyvinylpyrrolidone.

    Science.gov (United States)

    Lin, Shiuan-Pey; Hou, Yu-Chi; Liao, Tzu-Yun; Tsai, Shang-Yuan

    2014-03-01

    Preparation of magnolol-loaded amorphous solid dispersion was investigated for improving the bioavailability. A solid dispersion of magnolol was prepared with polyvinylpyrrolidone K-30 (PVP) by melting method, and the physical properties were characterized by using differential scanning calorimetry, powder X-ray diffractometry, Fourier transformation-infrared spectroscopy and scanning electron microscope. In addition, dissolution test was also performed. Subsequently, the bioavailability of magnolol pure compound, its physical mixture and solid dispersion were compared in rabbits. The blood samples withdrawn via marginal ear vein at specific time points were assayed by HPLC method. Oral administration of the solid dispersion of magnolol with PVP significantly increased the systemic exposures of magnolol and magnolol sulfates/glucuronides by 80.1% and 142.8%, respectively, compared to those given with magnolol pure compound. Magnolol-loaded amorphous solid dispersion with PVP has demonstrated enhanced bioavailability of magnolol in rabbits.

  5. 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...

  6. Bioavailability and bioactivity of intravenous vs subcutaneous infusion of growth hormone in GH-deficient patients

    DEFF Research Database (Denmark)

    Laursen, Torben; Møller, Jens; Ørskov, Hans

    1996-01-01

    Abstract OBJECTIVE: The bioavailability of GH immunoreactive serum concentrations is reduced following subcutaneous (s.c.) as compared with intravenous (i.v.) administration. Whether this difference also translates into a different biological activity remains to be investigated. The aim of the pr......Abstract OBJECTIVE: The bioavailability of GH immunoreactive serum concentrations is reduced following subcutaneous (s.c.) as compared with intravenous (i.v.) administration. Whether this difference also translates into a different biological activity remains to be investigated. The aim...... = 0.09) were observed on the two occasions. CONCLUSIONS: A reduced bioavailability of s.c. as compared with i.v. administered GH has been recorded with two independent GH assays, and this was also accompanied by a significant, albeit modest, reduction in biological activity....

  7. Bioavailability in rats of bound residues from radishes treated with either radiolabeled dieldrin or carbofuran

    International Nuclear Information System (INIS)

    Khan, S.U.; Kacew, S.; Dupont, S.; Stratton, G.D. Jr.; Wheeler, W.B.

    1987-01-01

    The bioavailability of bound residues from radishes treated with [ 14 C]dieldrin and [ 14 C]carbofuran was investigated by feeding the rats 14 C material obtained after exhaustive solvent extraction. For comparison, nonextracted radishes were also fed to rats. The 14 C residues were predominantly excreted in feces. Urinary excretion of 14 C from rats fed nonextracted material was relatively greater than from those fed extracted radishes. The excreted material from rats fed dieldrin-treated radishes contained mainly parent compounds as residue. However, carbofuran and two of its metabolites, 3-hydroxycarbofuran and 3-ketocarbofuran, were present in feces and urine samples of rats fed carbofuran-treated radishes. These data demonstrated that bound residues in radishes treated with dieldrin and carbofuran have a low degree of bioavailability in rats. The results also show that bound residues in dieldrin-treated radishes would be more bioavailable than in the carbofuran-treated samples

  8. 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.

  9. 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. Published by Elsevier Ltd.

  10. 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...... that the bioavailability of hesperidin was modulated by enzymatic conversion to hesperetin-7-glucoside, thus changing the absorption site from the colon to the small intestine. This may affect future interventions concerning the health benefits of citrus flavonoids....

  11. Novel piroxicam-loaded nanospheres generated by the electrospraying technique: physicochemical characterisation and oral bioavailability evaluation.

    Science.gov (United States)

    Mustapha, Omer; Din, Fakhar Ud; Kim, Dong Wuk; Park, Jong Hyuck; Woo, Kyu Bong; Lim, Soo-Jeong; Youn, Yu Seok; Cho, Kwan Hyung; Rashid, Rehmana; Yousaf, Abid Mehmood; Kim, Jong Oh; Yong, Chul Soon; Choi, Han-Gon

    2016-06-01

    To determine if a novel electrospraying technique could be applied to an oral drug delivery system for improving the solubility and oral bioavailability of poorly water-soluble piroxicam; the nanospheres were generated with drug and polyvinylpyrrolidone (PVP) using electrospraying technique; and their physicochemical properties, solubility, release and pharmacokinetics were evaluated in comparison with piroxicam powder. All nanospheres had significantly increased drug solubility and dissolution rates in comparison with the drug powder. In particular, the nanosphere composed of piroxicam and PVP at a weight ratio of 2:8 gave about 600-fold higher solubility, 15-fold higher release rate and 3-fold higher AUC in comparison to piroxicam powder, leading to significantly enhanced oral bioavailability in rats, due to the mingled effect of nanonisation along with transformation to the amorphous state. Thus, this electrospraying technique can be utilised to produce a novel oral nanosphere delivery system with enhanced solubility and oral bioavailability for poorly water-soluble piroxicam.

  12. Bioavailability of Dietary Omega-3 Fatty Acids Added to a Variety of Sausages in Healthy Individuals.

    Science.gov (United States)

    Köhler, Anton; Heinrich, Johanna; von Schacky, Clemens

    2017-06-19

    A low Omega-3 Index (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocytes) is associated with cardiac, cerebral, and other health issues. Intake of EPA and DHA, but not of alpha-linolenic acid (ALA), increases the Omega-3 Index. We investigated bioavailability, safety, palatability and tolerability of EPA and DHA in a novel source: a variety of sausages. We screened 96 healthy volunteers, and recruited 44 with an Omega-3 Index Omega-3 Index increased from 4.18 ± 0.54 to 5.72 ± 0.66% ( p Omega-3 Index per intake of EPA and DHA we observed was higher than for other sources previously studied, indicating superior bioavailability. As increasing production of EPA and DHA is difficult, improvements of bioavailability can facilitate reaching the target range for the Omega-3 Index (8-11%).

  13. Capmul MCM/Solutol HS15-Based Microemulsion for Enhanced Oral Bioavailability of Rebamipide.

    Science.gov (United States)

    Kim, Ki Taek; Lee, Jae-Young; Park, Ju-Hwan; Cho, Hyun-Jong; Yoon, In-Soo; Kim, Dae-Duk

    2017-04-01

    Rebamipide (RBP) is a potent anti-ulcer and anti-oxidative agent, which is a BCS class IV drug with a low oral bioavailability of less than 10%. Thus, the systemic absorption of RBP into the blood circulation is an essential prerequisite for exerting its pharmacological activities after oral dosing. Herein, we report on microemulsion (ME) systems for the enhancement of oral RBP bioavailability. In this study, MEs consisting of Capmul MCM (oil), Solutol HS15 (surfactant), and ethanol (co-surfactant) were prepared by the construction of pseudo-ternary phase diagram. The RBP-loaded MEs had spherical nano-sized droplets with narrow size distribution and neutral zeta potential. Moreover, the prepared MEs significantly enhanced the dissolution and oral bioavailability of RBP with no discernible intestinal toxicity. These results suggest that the present ME system could be further developed as an alternative oral formulation for RBP.

  14. Pan-Arctic Distribution of Bioavailable Dissolved Organic Matter and Linkages With Productivity in Ocean Margins

    Science.gov (United States)

    Shen, Yuan; Benner, Ronald; Kaiser, Karl; Fichot, Cédric G.; Whitledge, Terry E.

    2018-02-01

    Rapid environmental changes in the Arctic Ocean affect plankton productivity and the bioavailability of dissolved organic matter (DOM) that supports microbial food webs. We report concentrations of dissolved organic carbon (DOC) and yields of amino acids (indicators of labile DOM) in surface waters across major Arctic margins. Concentrations of DOC and bioavailability of DOM showed large pan-Arctic variability that corresponded to varying hydrological conditions and ecosystem productivity, respectively. Widespread hot spots of labile DOM were observed over productive inflow shelves (Chukchi and Barents Seas), in contrast to oligotrophic interior margins (Kara, Laptev, East Siberian, and Beaufort Seas). Amino acid yields in outflow gateways (Canadian Archipelago and Baffin Bay) indicated the prevalence of semilabile DOM in sea ice covered regions and sporadic production of labile DOM in ice-free waters. Comparing these observations with surface circulation patterns indicated varying shelf subsidies of bioavailable DOM to Arctic deep basins.

  15. Human intervention study to investigate the intestinal accessibility and bioavailability of anthocyanins from bilberries.

    Science.gov (United States)

    Mueller, Dolores; Jung, Kathrin; Winter, Manuel; Rogoll, Dorothee; Melcher, Ralph; Richling, Elke

    2017-09-15

    We investigated the importance of the large intestine on the bioavailability of anthocyanins from bilberries in humans with/without a colon. Low bioavailability of anthocyanins in plasma and urine was observed in the frame of this study. Anthocyanins reached the circulation mainly as glucuronides. Analysis of ileal effluents (at end of small intestine) demonstrated that 30% of ingested anthocyanins were stable during 8h passage through the upper intestine. Only 20% degradants were formed and mostly intact anthocyanins were absorbed from the small intestine. Higher amounts of degradants than anthocyanins reached the circulation after bilberry extract consumption in both groups of subjects. Comparison of the bioavailability of anthocyanins in healthy subjects versus ileostomists revealed substantially higher amounts of anthocyanins and degradants in the plasma/urine of subjects with an intact gut. The results suggested that the colon is a significant site for absorption of bioactive components such as anthocyanins and their degradation products. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    Yu Yunlong; Wu Xiaomao; Li Shaonan; Fang Hua; Zhan Haiyan; Yu Jingquan

    2006-01-01

    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 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 af and K df . However, only a slightly positive correlation between bioconcentration and K af and K df was observed for chlorpyrifos due to its high affinity onto soil. - Bioavailability of pesticides in soil to earthworm is governed by adsorption characteristics

  17. The oral bioavailability and toxicokinetics of methylmercury in common loon (Gavia immer) chicks

    Science.gov (United States)

    Fournier, F.; Karasov, W.H.; Kenow, K.P.; Meyer, M.W.; Hines, R.K.

    2002-01-01

    We compared the toxicokinetics of methylmercury in captive common loon chicks during two time intervals to assess the impact of feather growth on the kinetics of mercury. We also determined the oral bioavailability of methylmercury during these trials to test for age-related changes. The blood concentration-time curves for individuals dosed during feather development (initiated 35 days post hatch) were best described by a one-compartment toxicokinetic model with an elimination half-life of 3 days. The data for birds dosed following completion of feather growth (84 days post hatch) were best fitted by a two-compartment elimination model that includes an initial rapid distribution phase with a half-life of 0.9 days, followed by a slow elimination phase with a half-life of 116 days. We determined the oral bioavailability of methylmercury during the first dosing interval by comparing the ratios of the area under the blood concentration-time curves (AUC0→∞) for orally and intravenously dosed chicks. The oral bioavailability of methylmercury during the first dosing period was 0.83. We also determined bioavailability during both dosing periods using a second measure because of irregularities with intravenous results in the second period. This second bioavailability measure estimated the percentage of the dose that was deposited in the blood volume (f), and the results show that there was no difference in bioavailability among dosing periods. The results of this study highlight the importance of feather growth on the toxicokinetics of methylmercury.

  18. 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

  19. Bioavailable dissolved and particulate organic carbon flux from coastal temperate rainforest watersheds

    Science.gov (United States)

    Fellman, J.; Hood, E. W.; D'Amore, D. V.; Moll, A.

    2017-12-01

    Coastal temperate rainforest (CTR) watersheds of southeast Alaska have dense soil carbon stocks ( 300 Mg C ha-1) and high specific discharge (1.5-7 m yr-1) driven by frontal storms from the Gulf of Alaska. As a result, dissolved organic carbon (DOC) fluxes from Alaskan CTR watersheds are estimated to exceed 2 Tg yr-1; however, little is known about the export of particulate organic carbon (POC). The magnitude and bioavailability of this land-to-ocean flux of terrigenous organic matter ultimately determines how much metabolic energy is translocated to downstream and coastal marine ecosystems in this region. We sampled streamwater weekly from May through October from four watersheds of varying landcover (gradient of wetland to glacial coverage) to investigate changes in the concentration and flux of DOC and POC exported to the coastal ocean. We also used headspace analysis of CO2 following 14 day laboratory incubations to determine the flux of bioavailable DOC and POC exported from CTR watersheds. Across all sites, bioavailable DOC concentrations ranged from 0.2 to 1.9 mg L-1 but were on average 0.6 mg L-1. For POC, bioavailable concentrations ranged from below detection to 0.3 mg L-1 but were on average 0.1 mg L-1. The concentration, flux and bioavailability of DOC was higher than for POC highlighting the potential importance of DOC as a metabolic subsidy to downstream and coastal environments. Ratios of DOC to POC decreased during high flow events because the increase in POC concentrations with discharge exceeds that for DOC. Overall, our findings suggest that projected increases in precipitation and storm intensity will drive changes in the speciation, magnitude and bioavailability of the organic carbon flux from CTR watersheds.

  20. Phosphorus bioavailability in straw and sewage sludge ashes from low-temperature biomass gasification

    DEFF Research Database (Denmark)

    Müller-Stöver, Dorette Sophie; Jakobsen, Iver; Grønlund, Mette

    2017-01-01

    to their P bioavailability. A set of pot experiments with spring barley was carried out to compare the ash P fertiliser value with mineral P fertiliser and the sewage sludge feedstock. An indirect radioactive labelling approach with 33P was used to determine the amount of P taken up from the fertiliser....... In contrast, low- temperature gasification of Fe-rich sewage sludge reduced its P fertiliser value to practically zero. The results suggest that ashes from low-temperature gasification could be developed into alternative P fertilisers, however since their P bioavailability varies strongly depending...

  1. Reducing bioavailability and phytotoxicity of 2,4-dinitrotoluene by sorption on K-smectite clay.

    Science.gov (United States)

    Roberts, Michael G; Rugh, Clayton L; Li, Hui; Teppen, Brian J; Boyd, Stephen A

    2007-02-01

    Smectite clays demonstrate high affinities for nitroaromatics that strongly depend on the exchangeable cation. The K-smectites have high affinities for nitroaromatics, but Ca-smectites do not. Here we evaluate the ability of K-smectite to attenuate the bioavailability and hence toxicity of 2,4-dinitrotoluene (2,4-DNT) to the aquatic plant duckweed. In the absence of K-smectite, 2,4-DNT was highly toxic to duckweed. Small amounts of K-smectite reduced toxicity substantially, presumably by reducing 2,4-DNT bioavailability via sorption.

  2. 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.

  3. Influence of kinnow juice on the bioavailability of carbamazepine in healthy male volunteers.

    Science.gov (United States)

    Garg, S K; Bhargava, V K; James, H; KuJan-Mar, N; Prabhakar, S; Naresh, Ku

    1998-01-01

    Kinnow juice produces a marked and variable increase in carbamazepine bioavailability. The pharmacokinetics of carbamazepine was studied after drug administration with 300 ml water or kinnow juice in a randomized cross over trial on nine healthy male volunteers. With kinnow juice peak serum concentration (Cmax) and area under the serum concentration time curve (AUC) was significantly (P kinnow juice enhances carbamazepine bioavailability could be due to inhibition of cytochrome P-450 enzyme, since kinnow juice contains naringin which is considered to be inhibitor of liver microsomal dihydropyridine oxidation.

  4. Bioavailability of Cadmium and Zin to Two Earthworm Species in High-metal Soils

    OpenAIRE

    Liu, Ying

    2012-01-01

    It was generally recognized that the bioavailability, other than total content of heavy metals in soil, is crucial to predict metals' toxic effect on environment. Stable Isotope Dilution technique (SID) equipped with inductively coupled plasma-mass spectrometry (ICP-MS) is a good way for measuring the potential bioavailable portion of metals in soils. In Chapter 2, we build method to accurately determined Cd (111Cd/114Cd) and the ratio of Zn (66Zn/68Zn) in soil suspension and then applied thi...

  5. Lifelong physical activity prevents an age-related reduction in arterial and skeletal muscle nitric oxide bioavailability in humans

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Blackwell, James R; Damsgaard, Ramsus

    2012-01-01

    studied the effect of ROS on systemic and skeletal muscle NO bioavailability and leg blood flow by infusion of the antioxidant N-acetylcysteine (NAC). Infusion of NAC increased the bioavailability of NO in OS, as evidenced by an increased concentration of stable metabolites of NO (NOx) in the arterial...

  6. The impact of metal transport processes on bioavailability of free and complex metal ions in methanogenic granular sludge

    NARCIS (Netherlands)

    Bartacek, J.; Fermoso, F.G.; Vergeldt, F.; Gerkema, E.; Maca, J.; As, van H.; Lens, P.N.L.

    2012-01-01

    Bioavailability of metals in anaerobic granular sludge has been extensively studied, because it can have a major effect on metal limitation and metal toxicity to microorganisms present in the sludge. Bioavailability of metals can be manipulated by bonding to complexing molecules such as

  7. 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

  8. 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…

  9. 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...

  10. Enhancement of dissolution and oral bioavailability of lacidipine via pluronic P123/F127 mixed polymeric micelles: formulation, optimization using central composite design and in vivo bioavailability study.

    Science.gov (United States)

    Fares, Ahmed R; ElMeshad, Aliaa N; Kassem, Mohamed A A

    2018-11-01

    This study aims at preparing and optimizing lacidipine (LCDP) polymeric micelles using thin film hydration technique in order to overcome LCDP solubility-limited oral bioavailability. A two-factor three-level central composite face-centered design (CCFD) was employed to optimize the formulation variables to obtain LCDP polymeric micelles of high entrapment efficiency and small and uniform particle size (PS). Formulation variables were: Pluronic to drug ratio (A) and Pluronic P123 percentage (B). LCDP polymeric micelles were assessed for entrapment efficiency (EE%), PS and polydispersity index (PDI). The formula with the highest desirability (0.959) was chosen as the optimized formula. The values of the formulation variables (A and B) in the optimized polymeric micelles formula were 45% and 80%, respectively. Optimum LCDP polymeric micelles had entrapment efficiency of 99.23%, PS of 21.08 nm and PDI of 0.11. Optimum LCDP polymeric micelles formula was physically characterized using transmission electron microscopy. LCDP polymeric micelles showed saturation solubility approximately 450 times that of raw LCDP in addition to significantly enhanced dissolution rate. Bioavailability study of optimum LCDP polymeric micelles formula in rabbits revealed a 6.85-fold increase in LCDP bioavailability compared to LCDP oral suspension.

  11. Biomonitoring of trace metal bioavailabilities to the barnacle Amphibalanus amphitrite along the Iranian coast of the Persian Gulf.

    Science.gov (United States)

    Nasrolahi, A; Smith, B D; Ehsanpour, M; Afkhami, M; Rainbow, P S

    2014-10-01

    The fouling barnacle Amphibalanus amphitrite is a cosmopolitan biomonitor of trace metal bioavailabilities, with an international comparative data set of body metal concentrations. Bioavailabilities of As, Cd, Cr, Cu, Fe, Mn, Pb, V and Zn to A. amphitrite were investigated at 19 sites along the Iranian coast of the understudied Persian Gulf. Commercial and fishing ports showed extremely high Cu bioavailabilities, associated with high Zn bioavailabilities, possibly from antifouling paints and procedures. V availability was raised at one port, perhaps associated with fuel leakage. Cd bioavailabilities were raised at sites near the Strait of Hormuz, perhaps affected by adjacent upwelling off Oman. The As data allow a reinterpretation of the typical range of accumulated As concentrations in A. amphitrite. The Persian Gulf data add a new region to the A. amphitrite database, confirming its importance in assessing the ecotoxicologically significant trace metal contamination of coastal waters across the world. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. In vitro and in vivo approaches for the measurement of oral bioavailability of lead (Pb) in contaminated soils: A review

    International Nuclear Information System (INIS)

    Zia, Munir Hussain; Codling, Eton E.; Scheckel, Kirk G.; Chaney, Rufus L.

    2011-01-01

    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 Pb. Feeding tests have shown that urban soils may have much lower Pb bioavailability than previously assumed. Hence bioavailability of soil Pb is the important measure for protection of public health, not total soil Pb. Chemical extraction tests (Pb bioaccessibility) have been developed which are well correlated with the results of bioavailability tests; application of these tests can save money and time compared with feeding tests. Recent findings have revealed that fractional bioaccessibility (bioaccessible compared to total) of Pb in urban soils is only 5-10% of total soil Pb, far lower than the 60% as bioavailable as food-Pb presumed by U.S.-EPA (30% absolute bioavailability used in IEUBK model). - Highlights: → Among direct exposure pathways for Pb in urban environments, inadvertent ingestion of soil is considered the major concern. → The concentration of lead in house dusts is significantly related to that in garden soil, and is highest at older homes. → In modeling risks from diet/water/soil Pb, US-EPA presumes that soil-Pb is 60% as bioavailable as other dietary Pb. → Joplin study proved that RBALP method seriously underestimated the ability of phosphate treatments to reduce soil Pb bioavailability. → Zia et al. method has revealed that urban soils have only 5-10% bioaccessible Pb of total Pb level. - Improved risk evaluation and recommendations for Pb contaminated soils should be based on bioavailability-correlated bioaccessible soil Pb rather than total soil Pb.

  13. In vitro and in vivo approaches for the measurement of oral bioavailability of lead (Pb) in contaminated soils: A review

    Energy Technology Data Exchange (ETDEWEB)

    Zia, Munir Hussain, E-mail: MunirZia@gmail.com [Technical Services Department, Fauji Fertilizer Company Limited, Lahore (Pakistan); USDA-ARS, Environmental Management and By-products Utilization Laboratory, Bldg. 007, BARC-West, Beltsville, MD 20705-2350 (United States); Codling, Eton E. [USDA-ARS, Environmental Management and By-products Utilization Laboratory, Bldg. 007, BARC-West, Beltsville, MD 20705-2350 (United States); Scheckel, Kirk G. [US-Environmental Protection Agency, National Risk Management Research Laboratory Land Remediation and Pollution Control Division, 5995 Center Hill Avenue, Cincinnati, OH 45224-1702 (United States); Chaney, Rufus L. [USDA-ARS, Environmental Management and By-products Utilization Laboratory, Bldg. 007, BARC-West, Beltsville, MD 20705-2350 (United States)

    2011-10-15

    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 Pb. Feeding tests have shown that urban soils may have much lower Pb bioavailability than previously assumed. Hence bioavailability of soil Pb is the important measure for protection of public health, not total soil Pb. Chemical extraction tests (Pb bioaccessibility) have been developed which are well correlated with the results of bioavailability tests; application of these tests can save money and time compared with feeding tests. Recent findings have revealed that fractional bioaccessibility (bioaccessible compared to total) of Pb in urban soils is only 5-10% of total soil Pb, far lower than the 60% as bioavailable as food-Pb presumed by U.S.-EPA (30% absolute bioavailability used in IEUBK model). - Highlights: > Among direct exposure pathways for Pb in urban environments, inadvertent ingestion of soil is considered the major concern. > The concentration of lead in house dusts is significantly related to that in garden soil, and is highest at older homes. > In modeling risks from diet/water/soil Pb, US-EPA presumes that soil-Pb is 60% as bioavailable as other dietary Pb. > Joplin study proved that RBALP method seriously underestimated the ability of phosphate treatments to reduce soil Pb bioavailability. > Zia et al. method has revealed that urban soils have only 5-10% bioaccessible Pb of total Pb level. - Improved risk evaluation and recommendations for Pb contaminated soils should be based on bioavailability-correlated bioaccessible soil Pb rather than total soil Pb.

  14. Bioavailable iron in the Southern Ocean: the significance of the iceberg conveyor belt.

    Science.gov (United States)

    Raiswell, Rob; Benning, Liane G; Tranter, Martyn; Tulaczyk, Slawek

    2008-05-30

    Productivity in the Southern Oceans is iron-limited, and the supply of iron dissolved from aeolian dust is believed to be the main source from outside the marine reservoir. Glacial sediment sources of iron have rarely been considered, as the iron has been assumed to be inert and non-bioavailable. This study demonstrates the presence of potentially bioavailable Fe as ferrihydrite and goethite in nanoparticulate clusters, in sediments collected from icebergs in the Southern Ocean and glaciers on the Antarctic landmass. Nanoparticles in ice can be transported by icebergs away from coastal regions in the Southern Ocean, enabling melting to release bioavailable Fe to the open ocean. The abundance of nanoparticulate iron has been measured by an ascorbate extraction. This data indicates that the fluxes of bioavailable iron supplied to the Southern Ocean from aeolian dust (0.01-0.13 Tg yr(-1)) and icebergs (0.06-0.12 Tg yr(-1)) are comparable. Increases in iceberg production thus have the capacity to increase productivity and this newly identified negative feedback may help to mitigate fossil fuel emissions.

  15. Radioisotope 45Ca labeling four calcium chemical compounds and tracing calcium bioavailability

    International Nuclear Information System (INIS)

    Zheng Hui; Zhen Rong; Niu Huisheng; Li Huaifen

    2004-01-01

    Objective: To build up a new method of the radioisotope 45 Ca labeling four calcium chemical compounds, observe and tracing bioavailability change of calcium labeled with radioisotope 45 Ca. Methods: The calcium gluconate (Ca-Glu), calcium citrate (Ca-Cit), calcium carbonate (Ca-Car) and calcium L-threonate (Ca-Thr)were labeled by radioisotope 45 Ca. Four calcium chemical compounds of 45 Ca labeling were used of calcium content 200 mg/kg in the rats and measure the absorption content and bioavailability of calcium in tissue of heart, lever spleen, stomach, kidney, brain, intestine, whole blood, urine, faeces. Results: 1) Radioisotope 45 Ca labeling calcium chemical compound has high radio intensity, more steady standard curve and recover rate. 2) The absorption of organic calcium chemical compounds is higher than the inorganic calcium chemical compound in the study of calcium bioavailability. Conclusion: The method of tracing with radioisotope 45 Ca labeling calcium chemical compounds has the characteristic of the sensitive, objective, accurate and steady in the study of calcium bioavailability

  16. 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...

  17. 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.

  18. Iron bioavailability studies of the first generation of iron-biofortified beans released in Rwanda

    Science.gov (United States)

    This paper represents a series of in vitro Fe bioavailability experiments, Fe content analysis and polyphenolic profile of the first generation of Fe biofortified beans (Phaseolus vulgaris) selected for human trials in Rwanda and released to farmers of that region. The objective of the present stud...

  19. Ingested soil: Bioavailability of sorbed lead, cadmium, cesium, iodine, and mercury

    International Nuclear Information System (INIS)

    Sheppard, S.C.; Evenden, W.G.; Schwartz, W.J.

    1994-01-01

    Ingestion of soil, inadvertent or otherwise, is an important route of exposure for contaminants that are not geochemically or biologically mobile. There is little known about the bioavailability of these contaminants, especially when the contaminants are sorbed onto native soil particles. We investigated this with in vitro acid-extraction and enzymolysis experiments and with in vivo single and chronic exposure studies with mice (Mus musculus). The only anion studied was 125 I, and soil in the diet had no effect on the carcass 125 I content. The bioavailability of the cations tested decreased in the order of 134 Cs > 203 Hg > 115 Cd = 210 Pb, and the effect of soil in the diet on concentrations in the carcass decreased in the same order. Soil in the diet significantly decreased the bioavailability of 134 Cs, by more than fourfold, whereas the effect on 210 Pb was only ∼ 1.1-fold and was not significant. The results of the in vitro digestions ordered the elements in the same way as observed in the in vivo analyses. These results indicate that for contaminants that are not very mobile and are sorbed onto native soil particles, the presence of soil in the diet does not markedly affect bioavailability in the gut. (author)

  20. 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...

  1. Biological and chemical tests of contaminated soils to determine bioavailability and environmentally acceptable endpoints (EAE)

    International Nuclear Information System (INIS)

    Montgomery, C.R.; Menzie, C.A.; Pauwells, S.J.

    1995-01-01

    The understanding of the concept of bioavailability of soil contaminants to receptors and its use in supporting the development of EAE is growing but still incomplete. Nonetheless, there is increased awareness of the importance of such data to determine acceptable cleanup levels and achieve timely site closures. This presentation discusses a framework for biological and chemical testing of contaminated soils developed as part of a Gas Research Institute (GRI) project entitled ''Environmentally Acceptable Endpoints in Soil Using a Risk Based Approach to Contaminated Site Management Based on Bioavailability of Chemicals in Soil.'' The presentation reviews the GRI program, and summarizes the findings of the biological and chemical testing section published in the GRI report. The three primary components of the presentation are: (1) defining the concept of bioavailability within the existing risk assessment paradigm, (2) assessing the usefulness of the existing tests to measure bioavailability and test frameworks used to interpret these measurements, and (3) suggesting how a small selection of relevant tests could be incorporated into a flexible testing scheme for soils to address this issue

  2. Bioavailability and export of dissolved organic matter from a tropical river during base- and stormflow conditions

    Science.gov (United States)

    Tracy N. Wiegner; Randee L. Tubal; Richard A. MacKenzie

    2009-01-01

    Concentrations, bioavailability, and export of dissolved organic matter (DOM), particulate organic matter (POM), and nutrients from the Wailuku River, Hawai'i, U.S.A., were examined under base- and stormflow conditions. During storms, DOM and POM concentrations increased approximately by factors of 2 and 11, respectively, whereas NO3...

  3. Using bioavailability to assess contaminated sediment risk: Passive sampling and Pore Water Remedial Guidelines (PWRGs)

    Science.gov (United States)

    Hosted by the Contaminated Sediment Forum, this half-day course will introduce the RPM to the use of passive samplers to assess bioavailability and in ecological risk assessment. Passive sampling devices (PSD) are a technology with growing acceptance for measuring porewater conce...

  4. Comparison of mouse and swine bioassays for determination of soil arsenic relative bioavailability

    Science.gov (United States)

    Evaluation of soil arsenic (As) relative bioavailability (RBA) is essential to accurately assess human exposure to As contaminated soils via the incidental ingestion pathway. A variety of animal bioassays have been developed to estimate As RBA in contaminated soils and dusts, wit...

  5. Evidence for the bioavailability of PAH from oiled beach sediments in situ

    International Nuclear Information System (INIS)

    Hodson, P.V.; Cross, T.; Ewert, A.; Zambon, S.; Lee, K.

    2002-01-01

    Biological responses that reflect the flux of hydrocarbons through fish can be used to determine the impact that oil spills have on fish. In this study, the exposure and toxicity to fish of oiled sediments was assessed in a freshwater semidiurnal tidal area of the St. Lawrence River in Quebec and at a tidal salt marsh at Petpeswick Inlet in Nova Scotia. The effectiveness of wetland bioremediation strategies was assessed by monitoring the bioavailability and toxicity of oil-derived polycyclic aromatic hydrocarbons (PAH) to early life stages of fish. Bioavailability was assessed through laboratory bioassays of cytochrome P450 (CYP1A) enzymes in trout exposed to 500 g of sediments in 10 L of water. PAH was found to be still bioavailable to fish up to 14 months after oiling, but the extent of exposure decreased steadily over time. The study presented a worst-case scenario in which sediments are disturbed and mixed. When beach sediments were not disturbed, however, PAH was also bioavailable in situ 12 months after oiling, but to a much lesser degree. It was concluded that these tests are a good way to show the benefits of oil spill remediation in reducing the exposure of fish to PAH. 8 refs., 5 figs

  6. The role of sorption and bacteria in mercury partitioning and bioavailability in artificial sediments

    International Nuclear Information System (INIS)

    Zhong Huan; Wang Wenxiong

    2009-01-01

    This study compared the relative importance of three types of sorption (organic matter-particle, mercury-organic matter and mercury-particle) in controlling the overall mercury partitioning and bioavailability in sediments. We found that all three types of sorption were important for both inorganic mercury (Hg) and methylated mercury (MeHg). Mercury-particle sorption was more important than mercury-fulvic acid (FA) sorption in increasing the mercury concentrations with increasing aging. Bioavailability (quantified by gut juice extraction from sipunculans) was mainly controlled by mercury-particle sorption, while FA-particle and mercury-FA sorption were not as important, especially for MeHg. Bacterial activity also increased the partitioning of Hg or MeHg in the sediments and was further facilitated by the presence of organic matter. The bioavailability of Hg or MeHg from sediments was only slightly influenced by bacterial activity. This study highlights the importance of sorption from various sources (especially mercury-particle sorption) as well as bacteria in controlling the partitioning and bioavailability of Hg or MeHg in sediments. - Mercury-particle sorption was more important than mercury-organic matter and organic matter-particle sorption in controlling the partitioning of Hg or MeHg in sediments

  7. Influence of PEG coating on the oral bioavailability of gold nanoparticles in rats.

    Science.gov (United States)

    Alalaiwe, Ahmed; Roberts, Georgia; Carpinone, Paul; Munson, John; Roberts, Stephen

    2017-11-01

    Metallic nanoparticles can be produced in a variety of shapes, sizes, and surface chemistries, making them promising potential tools for drug delivery. Most studies to date have evaluated uptake of metallic nanoparticles from the GI tract with methods that are at best semi-quantitative. This study used the classical method of comparing blood concentration area under the curve (AUC) following intravenous and oral doses to determine the oral bioavailability of 1, 2 and 5 kDa PEG-coated 5 nm gold nanoparticles (AuNPs). Male rats were given a single intravenous dose (0.8 mg/kg) or oral (gavage) dose (8 mg/kg) of a PEG-coated AuNP, and the concentration of gold was measured in blood over time and in tissues (liver, spleen and kidney) at sacrifice. Blood concentrations following oral administration were inversely related to PEG size, and the AUC in blood was significantly greater for the 1 kDa PEG-coated AuNPs than particles coated with 2 or 5 kDa PEG. However, bioavailabilities of all of the particles were very low (bioavailability of AuNPs coated with PEG in the 1-5 kDa range, this study demonstrates the utility of applying the blood AUC approach to assess the quantitative oral bioavailability of metallic nanoparticles.

  8. Bioavailability of dissolved organic nitrogen (DON) in wastewaters from animal feedlots and storage lagoons

    Science.gov (United States)

    Dissolved organic nitrogen (DON) transport from animal agriculture to surface waters can lead to eutrophication and dissolved oxygen depletion. Biodegradable DON (BDON) is a portion of DON that is mineralized by bacteria while bioavailable DON (ABDON) is utilized by bacteria and/or algae. This stu...

  9. Soya phospholipid complex of mangiferin enhances its hepatoprotectivity by improving its bioavailability and pharmacokinetics.

    Science.gov (United States)

    Bhattacharyya, Sauvik; Ahmmed, Sk Milan; Saha, Bishnu Pada; Mukherjee, Pulok K

    2014-05-01

    Mangiferin is a xanthonoid present in Mangifera indica. It has been reported for a variety of pharmacological activities, including hepatoprotection. However, the major disadvantage of mangiferin is its reduced biological activity due to poor absorption, low bioavailability and rapid elimination from the body after administration. The aim of this study was to prepare a phospholipid complex of mangiferin to overcome these limitations and to investigate the impact of the complex on hepatoprotective activity and bioavailability. The results showed that the complex has an enhanced hepatoprotective and in vivo antioxidant activity as compared to pure mangiferin at the same dose level (30 and 60 mg kg⁻¹). The complex restored the levels of serum hepatic marker enzymes and liver antioxidant enzymes with respect to carbon tetrachloride-treated animals. The complex also increased the bioavailability of mangiferin in rat serum by 9.75-fold compared to pure mangiferin at the same dose level and enhanced the elimination half-life (t(1/2 el)) from 1.71 ± 0.12 h⁻¹ to 3.52 ± 0.27 h⁻¹. The results suggested that the complexation of mangiferin with soya phospholipid enhanced the hepatoprotection and in vivo antioxidant activity, which may be due to the improved bioavailability and pharmacokinetics of mangiferin in rat serum. © 2013 Society of Chemical Industry.

  10. 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.

  11. Carotenoid deposition in plant and animal foods and its impact on bioavailability.

    Science.gov (United States)

    Schweiggert, R M; Carle, R

    2017-06-13

    Over the past decades, an enormous body of literature dealing with the natural deposition of carotenoids in plant- and animal-based foods has accumulated. Prominent examples are the large solid-crystalline aggregates in carrots and tomatoes or the lipid-dissolved forms in dairy products and egg yolk. Latest research has identified lipid-dissolved forms in a rare number of plant foods, such as tangerine tomatoes and peach palm fruit (Bactris gasipaes Kunth). In addition, liquid-crystalline forms were assumed in so-called tubular chromoplasts of numerous fruits, e.g., in papaya, mango, and bell pepper. The bioavailability of carotenoids from fresh and processed foods strongly depends on their genuine deposition form, since their effective absorption to the human organism requires their liberation from the food matrix and subsequent solubilization into mixed micelles in the small intestine. Consequently, a broad overview about the natural array of carotenoid deposition forms should be helpful to better understand and modulate their bioavailability from foods. Furthermore, naturally highly bioavailable forms may provide biomimetic models for the improved formulation of carotenoids in food supplements. Therefore, this review paper presents scientific evidence from human intervention studies associating carotenoid deposition forms with their bioavailability, thus suggesting novel technological and dietary strategies for their enhanced absorption.

  12. Bioavailability of flavonoids and cinnamic acids and their effect on plasma homosysteine 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.

  13. The role of organic matter and clay content in sediments for bioavailability of pyrene.

    Science.gov (United States)

    Spasojević, Jelena; Maletić, Snežana; Rončević, Srđan; Grgić, Marko; Krčmar, Dejan; Varga, Nataša; Dalmacija, Božo

    2018-01-01

    Evaluation of the bioavailable fractions of organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) is extremely important for assessing their risk to the environment. This available fraction, which can be solubilised and/or easily extracted, is believed to be the most accessible for bioaccumulation, biosorption and/or transformation. Sediment organic matter (OM) and clay play an important role in the biodegradation and bioavailability of PAHs. The strong association of PAHs with OM and clay in sediments has a great influence not only on their distribution but also on their long-term environmental impact. This paper investigates correlations between bioavailability and the clay and OM contents in sediments. The results show that OM is a better sorbent for pyrene (chosen as a model PAH) and that increasing the OM content reduces the bioavailable fraction. A mathematical model was used to predict the kinetic desorption, and these results showed that the sediment with the lowest content of OM had an F fast value of 24%, whereas sediment with 20% OM gave a value of 9%. In the experiments with sediments with different clay contents, no clear dependence between clay and rate constants of the fast desorbing fractions was observed, which can be explained by the numerous possible interactions at the molecular level.

  14. 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.

  15. Tailored release drug delivery system for rifampicin and isoniazid for enhanced bioavailability of rifampicin.

    Science.gov (United States)

    Avachat, Amelia M; Bhise, Satish B

    2011-04-01

    The front line antitubercular drugs rifampicin (RMP) and isoniazid (INH), when co-administered, face the problem of reduced bioavailability of RMP. Stabilization of RMP in the presence of INH under acidic environment may improve the bioavailability of RMP. In vitro degradation studies showed around 15-25% degradation of RMP under the aforesaid conditions if the ratio of RMP: INH is above 1:0.5.This degradation is reduced to less than 10% when the ratio of RMP: INH is below 1:0.25. Based on these findings, an innovative drug delivery system was designed with the immediate release of RMP and tailored prolonged release of INH. The bilayer tablets prepared with this concept were subjected to relative bioavailability studies in healthy human volunteers in an open label, balanced, randomized, single-dose, cross-over study under fasted state. A validated LC-MS/MS bioanalytical method was employed for estimation of RMP and INH in plasma. Bioavailability studies revealed that C(max) and AUC for RMP increased by 18 and 20%, respectively, confirming the above innovative concept. Even in the case of INH, AUC increased significantly by around 30% and thus time above minimum inhibitory concentration (MIC) would also increase, which may result in further improved clinical outcome.

  16. Absolute Oral Bioavailability of Creatine Monohydrate in Rats: Debunking a Myth.

    Science.gov (United States)

    Alraddadi, Eman A; Lillico, Ryan; Vennerstrom, Jonathan L; Lakowski, Ted M; Miller, Donald W

    2018-03-08

    Creatine is an ergogenic compound used by athletes to enhance performance. Supplementation with creatine monohydrate (CM) has been suggested for musculoskeletal and neurological disorders. Until now, little is known about its pharmacokinetic profile. Our objective was to determine the oral bioavailability of CM and the influence of dose on oral absorption. Rats were dosed orally with low dose (10 mg/kg) or high dose (70 mg/kg) 13 C-labeled CM. Blood samples were removed at various time points. Muscle and brain tissue were collected at the conclusion of the study. Plasma and tissue levels of 13 C-labeled creatine were determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Physiologically based pharmacokinetic (PBPK) models of CM were built using GastroPlus™. These models were used to predict the plasma concentration-time profiles of creatine hydrochloride (CHCL), which has improved aqueous solubility compared to CM. Absolute oral bioavailability for low dose CM was 53% while high dose CM was only 16%. The simulated C max of 70 mg/kg CHCL was around 35 μg/mL compared to 14 μg/mL for CM with a predicted oral bioavailability of 66% with CHCL compared to 17% with CM. Our results suggest that the oral bioavailability of CM is less than complete and subject to dose and that further examination of improved dosage formulations of creatine is warranted.

  17. 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

    .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...

  18. Relative Bioavailability of Iron in Bangladeshi Traditional Meals Prepared with Iron-Fortified Lentil Dal

    Directory of Open Access Journals (Sweden)

    Rajib Podder

    2018-03-01

    Full Text Available Due to low Fe bioavailability and low consumption per meal, lentil must be fortified to contribute significant bioavailable Fe in the Bangladeshi diet. Moreover, since red lentil is dehulled prior to consumption, an opportunity exists at this point to fortify lentil with Fe. Thus, in the present study, lentil was Fe-fortified (using a fortificant Fe concentration of 2800 µg g−1 and used in 30 traditional Bangladeshi meals with broad differences in concentrations of iron, phytic acid (PA, and relative Fe bioavailability (RFeB%. Fortification with NaFeEDTA increased the iron concentration in lentil from 60 to 439 µg g−1 and resulted in a 79% increase in the amount of available Fe as estimated by Caco-2 cell ferritin formation. Phytic acid levels were reduced from 6.2 to 4.6 mg g−1 when fortified lentil was added, thereby reducing the PA:Fe molar ratio from 8.8 to 0.9. This effect was presumably due to dephytinization of fortified lentil during the fortification process. A significant (p ≤ 0.01 Pearson correlation was observed between Fe concentration and RFeB% and between RFeB% and PA:Fe molar ratio in meals with fortified lentil, but not for the meal with unfortified lentil. In conclusion, fortified lentil can contribute significant bioavailable Fe to populations at risk of Fe deficiency.

  19. Relative Bioavailability of Iron in Bangladeshi Traditional Meals Prepared with Iron-Fortified Lentil Dal.

    Science.gov (United States)

    Podder, Rajib; M DellaValle, Diane; T Tyler, Robert; P Glahn, Raymond; Tako, Elad; Vandenberg, Albert

    2018-03-15

    Due to low Fe bioavailability and low consumption per meal, lentil must be fortified to contribute significant bioavailable Fe in the Bangladeshi diet. Moreover, since red lentil is dehulled prior to consumption, an opportunity exists at this point to fortify lentil with Fe. Thus, in the present study, lentil was Fe-fortified (using a fortificant Fe concentration of 2800 µg g -1 ) and used in 30 traditional Bangladeshi meals with broad differences in concentrations of iron, phytic acid (PA), and relative Fe bioavailability (RFeB%). Fortification with NaFeEDTA increased the iron concentration in lentil from 60 to 439 µg g -1 and resulted in a 79% increase in the amount of available Fe as estimated by Caco-2 cell ferritin formation. Phytic acid levels were reduced from 6.2 to 4.6 mg g -1 when fortified lentil was added, thereby reducing the PA:Fe molar ratio from 8.8 to 0.9. This effect was presumably due to dephytinization of fortified lentil during the fortification process. A significant ( p ≤ 0.01) Pearson correlation was observed between Fe concentration and RFeB% and between RFeB% and PA:Fe molar ratio in meals with fortified lentil, but not for the meal with unfortified lentil. In conclusion, fortified lentil can contribute significant bioavailable Fe to populations at risk of Fe deficiency.

  20. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Comparison of the gastrointestinal absorption and bioavailability of fenofibrate and fenofibric acid in humans.

    Science.gov (United States)

    Zhu, Tong; Ansquer, Jean-Claude; Kelly, Maureen T; Sleep, Darryl J; Pradhan, Rajendra S

    2010-08-01

    This study compared the gastrointestinal (GI) absorption characteristics and absolute bioavailability of fenofibric acid and fenofibrate (which is converted to fenofibric acid in vivo) in healthy volunteers. Treatments were delivered to the proximal small bowel, distal small bowel, and colon using a site-specific delivery system (Enterion capsule) and to the stomach by oral administration of equimolar doses. Serial blood samples were collected for 120 hours postdose and assayed for plasma fenofibric acid concentrations. The absolute bioavailability of each treatment was determined relative to 50 mg of fenofibric acid administered intravenously. Plasma exposure to fenofibric acid following fenofibric acid administration was approximately 1.5 times higher than that following fenofibrate administration for delivery to the proximal and distal small bowel and following oral administration, and it was approximately 5 times higher following colon delivery. The absolute bioavailability in the stomach, proximal small bowel, distal small bowel, and colon was approximately 81%, 88%, 84%, and 78%, respectively, for fenofibric acid and 69%, 73%, 66%, and 22%, respectively, for fenofibrate (P < .0001 and P = .033 for fenofibric acid vs fenofibrate in the colon and distal small bowel, respectively). In conclusion, fenofibric acid is well absorbed throughout the GI tract and has greater bioavailability than fenofibrate in all GI regions.

  2. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Influence of natural dissolved organic carbon on the bioavailability of mercury to a freshwater alga

    International Nuclear Information System (INIS)

    Gorski, P.R.; Armstrong, D.E.; Hurley, J.P.; Krabbenhoft, D.P.

    2008-01-01

    Bioavailability of mercury (Hg) to Selenastrum capricornutum was assessed in bioassays containing field-collected freshwater of varying dissolved organic carbon (DOC) concentrations. Bioconcentration factor (BCF) was measured using stable isotopes of methylmercury (MeHg) and inorganic Hg(II). BCFs for MeHg in low-DOC lake water were significantly larger than those in mixtures of lake water and high-DOC river water. The BCF for MeHg in rainwater (lowest DOC) was the largest of any treatment. Rainwater and lake water also had larger BCFs for Hg(II) than river water. Moreover, in freshwater collected from several US and Canadian field sites, BCFs for Hg(II) and MeHg were low when DOC concentrations were >5 mg L -1 . These results suggest high concentrations of DOC inhibit bioavailability, while low concentrations may provide optimal conditions for algal uptake of Hg. However, variability of BCFs at low DOC indicates that DOC composition or other ligands may determine site-specific bioavailability of Hg. - Bioavailability of mercury to an alga was greatest at low concentrations of natural dissolved organic carbon and inhibited at high concentrations of natural dissolved organic carbon

  4. Using soil properties to predict in vivo bioavailability of lead in soils.

    Science.gov (United States)

    Wijayawardena, M A Ayanka; Naidu, Ravi; Megharaj, Mallavarapu; Lamb, Dane; Thavamani, Palanisami; Kuchel, Tim

    2015-11-01

    Soil plays a significant role in controlling the potential bioavailability of contaminants in the environment. In this study, eleven soils were used to investigate the relationship between soil properties and relative bioavailability (RB) of lead (Pb). To minimise the effect of source of Pb on in vivo bioavailability, uncontaminated study soils were spiked with 1500 mg Pb/kg soil and aged for 10-12 months prior to investigating the relationships between soil properties and in vivo RB of Pb using swine model. The biological responses to oral administration of Pb in aqueous phase or as spiked soils were compared by applying a two-compartment pharmacokinetic model to blood Pb concentration. The study revealed that RB of Pb from aged soils ranged from 30±9% to 83±7%. The very different RB of Pb in these soils was attributed to variations in the soils' physico-chemical properties. This was established using sorption studies showing: firstly, Freundlich partition coefficients that ranged from 21 to 234; and secondly, a strongly significant (R(2)=0.94, Psoils. To the best of our knowledge, this is the first such model derived using sorption partition coefficient to predict the relative bioavailability of Pb. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Modification of an Existing In vitro Method to Predict Relative Bioavailable Arsenic in Soils

    Science.gov (United States)

    The soil matrix can sequester arsenic (As) and reduces its exposure by soil ingestion. In vivo dosing studies and in vitro gastrointestinal (IVG) methods have been used to predict relative bioavailable (RBA) As. Originally, the Ohio State University (OSU-IVG) method predicted R...

  6. Dry elixir formulations of dexibuprofen for controlled release and enhanced oral bioavailability.

    Science.gov (United States)

    Kim, Seo-Ryung; Kim, Jin-Ki; Park, Jeong-Sook; Kim, Chong-Kook

    2011-02-14

    The objective of this study was to achieve an optimal formulation of dexibuprofen dry elixir (DDE) for the improvement of dissolution rate and bioavailability. To control the release rate of dexibuprofen, Eudragit(®) RS was employed on the surface of DDE resulting in coated dexibuprofen dry elixir (CDDE). Physicochemical properties of DDE and CDDE such as particle size, SEM, DSC, and contents of dexibuprofen and ethanol were characterized. Pharmacokinetic parameters of dexibuprofen were evaluated in the rats after oral administration. The DDE and CDDE were spherical particles of 12 and 19 μm, respectively. The dexibuprofen and ethanol contents in the DDE were dependent on the amount of dextrin and maintained for 90 days. The dissolution rate and bioavailability of dexibuprofen loaded in dry elixir were increased compared with those of dexibuprofen powder. Moreover, coating DDE with Eudragit(®) RS retarded the dissolution rate of dexibuprofen from DDE without reducing the bioavailability. Our results suggest that CDDE may be potential oral dosage forms to control the release and to improve the bioavailability of poorly water-soluble dexibuprofen. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. 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...

  8. 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.

  9. Effect of taste masking technology on fast dissolving oral film: dissolution rate and bioavailability

    Science.gov (United States)

    Zhu, Ying; You, Xinru; Huang, Keqing; Raza, Faisal; Lu, Xin; Chen, Yuejian; Dhinakar, Arvind; Zhang, Yuan; Kang, Yang; Wu, Jun; Ge, Liang

    2018-07-01

    Fast dissolving oral film is a stamp-style, drug-loaded polymer film with rapid disintegration and dissolution. This new kind of drug delivery system requires effective taste masking technology. Suspension intermediate and liposome intermediate were prepared, respectively, for the formulation of two kinds of fast dissolving oral films with the aim of studying the effect of taste masking technology on the bioavailability of oral films. Loratadine was selected as the model drug. The surface pH of the films was close to neutral, avoiding oral mucosal irritation or side effects. The thickness of a 2 cm × 2 cm suspension oral film containing 10 mg of loratadine was 100 μm. Electron microscope analysis showed that liposomes were spherical before and after re-dissolution, and drugs with obvious bitterness could be masked by the encapsulation of liposomes. Dissolution of the two films was superior to that of the commercial tablets. Rat pharmacokinetic experiments showed that the oral bioavailability of the suspension film was significantly higher than that of the commercial tablets, and the relative bioavailability of the suspension film was 175%. Liposomal film produced a certain amount of improvement in bioavailability, but lower than that of the suspension film.

  10. 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

  11. Pharmacokinetics and enhanced bioavailability of candidate cancer preventative agent, SR13668 in dogs and monkeys.

    Science.gov (United States)

    Kapetanovic, Izet M; Muzzio, Miguel; Hu, Shu-Chieh; Crowell, James A; Rajewski, Roger A; Haslam, John L; Jong, Ling; McCormick, David L

    2010-05-01

    SR13668 (2,10-dicarbethoxy-6-methoxy-5,7-dihydro-indolo-(2,3-b)carbazole), is a new candidate cancer chemopreventive agent under development. It was designed using computational modeling based on a naturally occurring indole-3-carbinol and its in vivo condensation products. It showed promising anti-cancer activity and its preclinical toxicology profile (genotoxicity battery and subchronic rat and dog studies) was unremarkable. However, it exhibited a very poor oral bioavailability (Solutol, were tested in dogs and monkeys. Levels of SR13668 were measured in plasma and blood using a high-performance liquid chromatograph-tandem mass spectrometer system. Non-compartmental analysis was used to derive pharmacokinetic parameters including the bioavailability. The Solutol formulation yielded better bioavailability reaching a maximum of about 14.6 and 7.3% in dogs and monkeys, respectively, following nominal oral dose of ca. 90 mg SR13668/m(2). Blood levels of SR13668 were consistently about threefold higher than those in plasma in both species. SR13668 did not cause untoward hematology, clinical chemistry, or coagulation effects in dogs or monkeys with the exception of a modest, reversible increase in liver function enzymes in monkeys. The lipid-based surfactant/emulsifiers, especially Solutol, markedly enhanced the oral bioavailability of SR13668 over that previously seen in preclinical studies. These formulations are being evaluated in a Phase 0 clinical study prior to further clinical development of this drug.

  12. 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...

  13. Human intrinsic factor expression for bioavailable vitamin B12 enrichment in microalgae

    DEFF Research Database (Denmark)

    Lima, Serena; Webb, Conner L.; Deery, Evelyne

    2018-01-01

    Dietary supplements and functional foods are becoming increasingly popular complements to regular diets. A recurring ingredient is the essential cofactor vitamin B12(B12). Microalgae are making their way into the dietary supplement and functional food market but do not produce B12, and their B12 ...... that is suitable for vegetarians and, potentially, more bioavailable for humans....

  14. Decreased Bioavailability of Rifampicin and other anti-TB drugs in ...

    Indian Academy of Sciences (India)

    ... and rifampin in blood and of pyrazinamide and ethambutol in urine. Peak concentration and exposure of rifampicin was reduced. Rapid acetylators of isoniazid had lower drug levels. HIV and HIV-tuberculosis patients who have diarrhea and cryptosporidial infection exhibit decreased bioavailability of antituberculosis drugs.

  15. Comparison of oral artesunate and dihydroartemisinin antimalarial bioavailabilities in acute falciparum malaria

    NARCIS (Netherlands)

    Newton, Paul N.; van Vugt, Michele; Teja-Isavadharm, Paktiya; Siriyanonda, Duangsuda; Rasameesoroj, Maneerat; Teerapong, Pramote; Ruangveerayuth, Ronatrai; Slight, Thra; Nosten, Francois; Suputtamongkol, Yupin; Looareesuwan, Sornchai; White, Nicholas J.

    2002-01-01

    Plasma antimalarial activity following oral artesunate or dihydroartemisinin (DHA) treatment was measured by a bioassay in 18 patients with uncomplicated falciparum malaria. The mean antimalarial activity in terms of the bioavailability of DHA relative to that of artesunate did not differ

  16. Application of an in vivo swine model for the determination of arsenic bioavailability in contaminated vegetables.

    Science.gov (United States)

    Juhasz, Albert L; Smith, Euan; Weber, John; Rees, Matthew; Rofe, Allan; Kuchel, Tim; Sansom, Lloyd; Naidu, Ravi

    2008-05-01

    Considerable information is available in the literature regarding the uptake of arsenic (As) from contaminated soil and irrigation water by vegetables. However, few studies have investigated As speciation in these crops while a dearth of information is available on As bioavailability following their consumption. In this study, the concentration and speciation of As in chard, radish, lettuce and mung beans was determined following hydroponic growth of the vegetables using As-contaminated water. In addition, As bioavailability was assessed using an in vivo swine feeding assay. While As concentrations ranged from 3.0 to 84.2mg As kg(-1) (dry weight), only inorganic As (arsenite and arsenate) was detected in the edible portions of the vegetables. When As bioavailability was assessed through monitoring blood plasma As concentrations following swine consumption of As-contaminated vegetables, between 50% and 100% of the administered As dose was absorbed and entered systemic circulation. Arsenic bioavailability decreased in the order mung beans>radish>lettuce=chard.

  17. Effect of taste masking technology on fast dissolving oral film: dissolution rate and bioavailability.

    Science.gov (United States)

    Zhu, Ying; You, Xinru; Huang, Keqing; Raza, Faisal; Lu, Xin; Chen, Yuejian; Dhinakar, Arvind; Zhang, Yuan; Kang, Yang; Wu, Jun; Ge, Liang

    2018-07-27

    Fast dissolving oral film is a stamp-style, drug-loaded polymer film with rapid disintegration and dissolution. This new kind of drug delivery system requires effective taste masking technology. Suspension intermediate and liposome intermediate were prepared, respectively, for the formulation of two kinds of fast dissolving oral films with the aim of studying the effect of taste masking technology on the bioavailability of oral films. Loratadine was selected as the model drug. The surface pH of the films was close to neutral, avoiding oral mucosal irritation or side effects. The thickness of a 2 cm × 2 cm suspension oral film containing 10 mg of loratadine was 100 μm. Electron microscope analysis showed that liposomes were spherical before and after re-dissolution, and drugs with obvious bitterness could be masked by the encapsulation of liposomes. Dissolution of the two films was superior to that of the commercial tablets. Rat pharmacokinetic experiments showed that the oral bioavailability of the suspension film was significantly higher than that of the commercial tablets, and the relative bioavailability of the suspension film was 175%. Liposomal film produced a certain amount of improvement in bioavailability, but lower than that of the suspension film.

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

    International Nuclear Information System (INIS)

    Amaral, Andre; Soto, Manu; Cunha, Regina; Marigomez, Ionan; Rodrigues, Armindo

    2006-01-01

    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

  19. 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.

  20. 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. Copyright © 2014 John Wiley & Sons, Ltd.

  1. 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,

  2. Effects of sediment composition on inorganic mercury partitioning, speciation and bioavailability in oxic surficial sediments

    International Nuclear Information System (INIS)

    Zhong Huan; Wang Wenxiong

    2008-01-01

    Artificially prepared sediments were used to assess the effects of sediment composition on inorganic Hg partitioning, speciation and bioavailability. Organic coating in sediment greatly increased the Hg partitioning and the amount of bioavailable Hg bound with the clay and the Fe and Mn oxides, but had little effect on that bound with the quartz and calcium carbonate as a result of weaker binding of humic acids and fulvic acids. The clay content increased the concentration of Hg in the sediments but inhibited the gut juice extraction due to the strong binding of Hg-organic matter (OM) complexes. Most Hg in the sediments was complexed by OM (mainly distributed in the organo-complexed phase and the strongly complexed phase), and the Hg-OM complexes (especially Hg in the strongly complexed phase) in sediments contributed much to gut juice extraction. Redistribution of Hg-OM complexes between sediments and gut juices may occur during gut juice extraction and modify Hg bioavailability and speciation in sediments. - Organic and clay contents in sediments are the two most important components controlling Hg partitioning in sediments and bioavailability

  3. Bioavailability of higher dose methotrexate comparing oral and subcutaneous administration in patients with rheumatoid arthritis

    NARCIS (Netherlands)

    Hoekstra, Monique; Haagsma, C.; Neef, C; Proost, Johannes H; Knuif, A.; van der Laar, M.

    Objective. To determine the bioavailability of higher oral doses of methotrexate (MTX) in adult patients with rheumatoid arthritis (RA). Methods. A pharmacokinetic analysis was performed in 15 patients with RA taking a stable dose of MTX (greater than or equal to25 mg weekly). Separated by 2 weeks,

  4. Bioavailability and kinetics of sulforaphane in humans after consumption of cooked versus raw broccoli

    NARCIS (Netherlands)

    Vermeulen, M.; Klöpping-Ketelaars, I.W.A.A.; Berg, R. van den; Vaes, W.H.J.

    2008-01-01

    The aim of this study was to determine the bioavailability and kinetics of the supposed anticarcinogen sulforaphane, the hydrolysis product of glucoraphanin, from raw and cooked broccoli. Eight men consumed 200 g of crushed broccoli, raw or cooked, with a warm meal in a randomized, free-living, open

  5. Bioavailability of isoflavones from soy products in equol producers and non-producers in Japanese women

    Directory of Open Access Journals (Sweden)

    Ayako Miura

    2016-12-01

    Conclusions: The results in this study suggest that bioavailability of isoflavones are different between equol producers and non-producers, because the 24 h urinary excretion of equol in the equol producers were significantly lower than those in the equol non-producers.

  6. The role of sorption and bacteria in mercury partitioning and bioavailability in artificial sediments

    Energy Technology Data Exchange (ETDEWEB)

    Zhong Huan [Atmospheric, Marine and Coastal Environment Program and Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong); Wang Wenxiong [Atmospheric, Marine and Coastal Environment Program and Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong)], E-mail: wwang@ust.hk

    2009-03-15

    This study compared the relative importance of three types of sorption (organic matter-particle, mercury-organic matter and mercury-particle) in controlling the overall mercury partitioning and bioavailability in sediments. We found that all three types of sorption were important for both inorganic mercury (Hg) and methylated mercury (MeHg). Mercury-particle sorption was more important than mercury-fulvic acid (FA) sorption in increasing the mercury concentrations with increasing aging. Bioavailability (quantified by gut juice extraction from sipunculans) was mainly controlled by mercury-particle sorption, while FA-particle and mercury-FA sorption were not as important, especially for MeHg. Bacterial activity also increased the partitioning of Hg or MeHg in the sediments and was further facilitated by the presence of organic matter. The bioavailability of Hg or MeHg from sediments was only slightly influenced by bacterial activity. This study highlights the importance of sorption from various sources (especially mercury-particle sorption) as well as bacteria in controlling the partitioning and bioavailability of Hg or MeHg in sediments. - Mercury-particle sorption was more important than mercury-organic matter and organic matter-particle sorption in controlling the partitioning of Hg or MeHg in sediments.

  7. Food Stabilizing Antioxidants Increase Nutrient Bioavailability in the in Vitro Model.

    Science.gov (United States)

    Mika, Magdalena; Wikiera, Agnieszka; Antończyk, Anna; Grabacka, Maja

    2017-01-01

    We investigated whether antioxidants may enhance bioavailability of lipids and carbohydrates and therefore increase the risk of obesity development. We tested how supplementation with antioxidants (0.01% butylated hydroxytoluene [BHT], α-tocopherol, and green tea catechins) of a diet containing butter and wheat bread affects bioavailability of fats and carbohydrates. The absorption of the in vitro digested diet was estimated in the intestinal epithelia model of the Caco-2 cells cultured in Transwell chambers. In the case of the antioxidant-supplemented diets, we observed increased bioavailability of glucose, cholesterol, and lipids, as well as elevated secretion of the main chylomicron protein apoB-48 to the basal compartment. Importantly, we did not detect any rise in the concentrations of lipid peroxidation products (malondialdehyde, MDA) in the control samples prepared without antioxidants. Addition of antioxidants (in particular BHT) to the diet increases bioavailability of lipids and carbohydrates, which consequently may increase the risk of obesity development. The dose of antioxidants is a factor of fundamental importance, particularly for catechins: low doses increase absorption of lipids, whereas high doses exert the opposite effect.

  8. Controlled release of glaucocalyxin - a self-nanoemulsifying system from osmotic pump tablets with enhanced bioavailability.

    Science.gov (United States)

    Yanfei, Miao; Guoguang, Chen; Lili, Ren; Pingkai, Ouyang

    2017-03-01

    The purpose of this study was to develop a new formulation to enhance the bioavailability simultaneously with controlled release of glaucocalyxin A (GLA). In this study, controlled release of GLA was achieved by the osmotic release strategy taking advantage of the bioavailability enhancing capacity of self-nanoemulsifying drug delivery systems (SNEDDS). The formulation of GLA-SNEDDS was selected by the solubility and pseudoternary-phase diagrams studies. The prepared GLA-SNEDDS formulations were characterized for self-emulsification time, effect of pH and robustness to dilution, droplet size analysis and zeta potential. The optimized GLA-SNEDDS were used to prepare GLA-SNEDDS osmotic pump tablet via direct powder compression method. The effect of formulation variables on the release characteristic was investigated. GLA-SNEDDS osmotic pump tablets were administered to beagle dogs and their pharmacokinetics were compared to GLA and GLA-SNEDDS as a control. In vitro drug release studies indicated that the GLA-SNEDDS osmotic pump tablet showed sustained release profiles with 90% released within 12 h. Pharmacokinetic study showed steady blood GLA with prolonged T max and mean residence time (MRT), and enhanced bioavailability for GLA-SNEDDS osmotic pump tablet. It was concluded that simultaneous controlling on GLA release and enhanced bioavailability had been achieved by a combination of osmotic pump tablet and SNEDDS.

  9. 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

    2006-03-09

    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.

  10. IN VITRO CARDIOTOXICITY OF AIR POLLUTION PARTICLES: ROLE OF BIOAVAILABLE CONSTITUENTS, OXIDATIVE STRESS AND TYROSINE PHOSPHORYLATION

    Science.gov (United States)

    IN VITRO CARDIOTOXICITY OF AIR POLLUTION PARTICLES: ROLE OF BIOAVAILABLE CONSTITUENTS, OXIDATIVE STRESS AND TYROSINE PHOSPHORYLATION.T. L. Knuckles1 R. Jaskot2, J. Richards2, and K.Dreher2.1Department of Molecular and Biomedical Sciences, College of Veterinary Medicin...

  11. Effect of type of TAG fatty acids on lutein and zeaxanthin bioavailability.

    Science.gov (United States)

    Gleize, Béatrice; Tourniaire, Franck; Depezay, Laurence; Bott, Romain; Nowicki, Marion; Albino, Lionel; Lairon, Denis; Kesse-Guyot, Emmanuelle; Galan, Pilar; Hercberg, Serge; Borel, Patrick

    2013-07-14

    The xanthophylls lutein and zeaxanthin probably play a role in visual function and may participate in the prevention of age-related eye diseases. Although a minimum amount of TAG is required for an optimal bioavailability of these carotenoids, the effect of the type of TAG fatty acids (FA) is less clear. The aim was to assess the effect of the type of TAG FA on bioavailability of these xanthophylls. A total of three complementary models were used: an in vitro digestion model to study bioaccessibility, Caco-2 cells to study uptake efficiency and orally administered rats to study in vivo bioavailability. Results showed that lutein and zeaxanthin bioaccessibility was greater (about 20-30 %, Pxanthophyll uptake by Caco-2 cells, but some compounds present in natural oils significantly affected xanthophyll uptake. Oral administration of rats with spinach and butter over 3 d led to a higher fasting plasma lutein concentration than oral administration with olive or fish oils. In conclusion, dietary fats rich in SFA lead to a higher bioavailability of lutein and zeaxanthin, as compared with fats rich in MUFA and PUFA. This is due partly to the higher bioaccessibility of these xanthophylls in the smaller mixed micelles produced when SFA are incorporated into mixed micelles.

  12. 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.

  13. Copper bioavailability from breakfasts containing tea : influence of the addition of milk

    NARCIS (Netherlands)

    Vaquero, M.P.; Veldhuizen, M.; Dokkum, W. van; Hamer, C.J.A. van den; Schaafsma, G.

    1994-01-01

    The influence of drinking tea on copper bioavailability is unclear, particularly when tea is consumed with food. A breakfast meal containing white bread, margarine, strawberry jam, cheese and tea, with or without milk, was digested in; vitro and the dialysis of copper investigated. Reference

  14. 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

  15. 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

  16. The toxicity of different lead salts to Enchytraeus crypticus in relation to bioavailability in soil

    NARCIS (Netherlands)

    Zhang, Lulu; Van Gestel, Cornelis A.M.

    2017-01-01

    The present study aimed to assess the bioavailability and toxicity of lead nitrate and lead chloride to Enchytraeus crypticus in a natural standard soil. Worms were exposed to Pb-spiked soil for 21 d, and survival and reproduction were related to total, 0.01 M CaCl2-extractable, and porewater Pb

  17. Effects of plant growth stage on the bioavailability of cesium and strontium in rhizosphere soil

    International Nuclear Information System (INIS)

    Nakamaru, Yasuo

    2006-01-01

    The effects of plant growth stage on the bioavailability of Cs and Sr in rhizosphere soil were studied by soybean pot experiments. Soybean seeds were sown into 12 pots and the plants were grown in a greenhouse for 84 d. Three pots were kept unplanted. The concentrations of Mg, K, Ca, Sr and Cs in plants and in soil solutions at different growth periods were measured. The mass flow of the elements from soil solution to the root surface was calculated from the concentrations in the soil solution and daily transpiration of the soybean plant. The concentrations of elements in the soil solution decreased as the soybean plants grew. The decrease of Mg, K, Ca, and Sr was high in planted pots. The differences in Mg, K, Ca, and Sr concentrations between the planted and the unplanted pots indicated that the active uptake of these elements by the soybean plants caused the drop in their concentrations. However, no obvious difference in Cs concentrations was seen between the planted and the unplanted ports. Although the ratio of mass flow to actual uptake of Cs was 1.4 for the vegetative growth stage, it increased to 4.2 for the podding stage. This meant that the Cs mass flow was in excess of what was absorbed by the plants, so the Cs uptake was inhibited near the roots for the podding stage. It was assumed that the increase of Cs sorption due to the K concentration decrease in soil solution decreased the Cs bioavailability in the rhizosphere soil. The bioavailability of Cs and Sr in the rhizosphere was examined in a small-scale pot experiment. The soil-soil solution distribution coefficients (K d ) of Cs and Sr were observed as an index of their sorption level. K d of Cs increased in the rhizosphere soil after cultivation. The decrease of bioavailable fraction of soil Cs was also observed. The exchangeable Cs in the rhizosphere soil clearly decreased. On the other hand, no specific rhizosphere effect was observed for Sr bioavailability. These results showed that the Cs

  18. 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

  19. Bioavailability of cadmium adsorbed on various oxides minerals to wetland plant species Phragmites australis

    International Nuclear Information System (INIS)

    Wang He; Jia Yongfeng; Wang Shaofeng; Zhu Huijie; Wu Xing

    2009-01-01

    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) 3 > Al 2 O 3 > Fe 3 O 4 > MnO 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) 3 > Fe 3 O 4 > Al 2 O 3 > FeOOH > MnO 2 , while by citric acid: Al(OH) 3 ≥ Al 2 O 3 > Fe 3 O 4 > FeOOH > MnO 2 . This was consistent with the Cd accumulation degree in the plant. Cd adsorbed on Al(OH) 3 was the most easily desorbable species and most bioavailable to P. australis among the oxide minerals, whereas MnO 2 adsorbed Cd was least desorbable by LMWOAs hence constituted the least bioavailable Cd species adsorbed on the oxide minerals.

  20. Enhancement of oral bioavailability of anti-HIV drug rilpivirine HCl through nanosponge formulation.

    Science.gov (United States)

    Zainuddin, Rana; Zaheer, Zahid; Sangshetti, Jaiprakash N; Momin, Mufassir

    2017-12-01

    To synthesize β cyclodextrin nanosponges using a novel and efficient microwave mediated method for enhancing bioavailability of Rilpivirine HCl (RLP). Belonging to BCS class II RLP has pH dependent solubility and poor oral bioavailability. However, a fatty meal enhances its absorption hence the therapy indicates that the dosage form be consumed with a meal. But then it becomes tedious and inconvenient to continue the therapy for years with having to face the associated gastric side effects such as nausea. Microwave synthesizer was used to mediate the poly-condensation reaction between β-cyclodextrin and cross-linker diphenylcarbonate. Critical parameters selected were polymer to cross-linker ratio, Watt power, reaction time and solvent volume. Characterization studies were performed using FTIR, DSC, SEM, 1 H-NMR and PXRD. Molecular modeling was applied to confirm the possibility of drug entrapment. In vitro drug dissolution followed by oral bioavailability studies was performed in Sprawley rats. Samples were analyzed using HPLC. Microwave synthesis yields para-crystalline, porous nanosponges (∼205 nm). Drug entrapment led to enhancement of solubility and a two-fold increase in drug dissolution (P bioavailability was observed in fasted Sprawley rats where C max and AUC 0-∞ increases significantly (C max of NS∼ 586 ± 5.91 ng/mL; plain RLP ∼310 ± 5. 74 ng/mL). The approach offers a comfortable dosing zone for AIDs patients, negating the requirement of consuming the formulation in a fed state due to enhancement in drugs' oral bioavailability.

  1. Silica-coated flexible liposomes as a nanohybrid delivery system for enhanced oral bioavailability of curcumin

    Directory of Open Access Journals (Sweden)

    Li C

    2012-12-01

    Full Text Available Chong Li, Yan Zhang, Tingting Su, Lianlian Feng, Yingying Long, Zhangbao ChenKey Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, ChinaAbstract: We investigated flexible liposomes as a potential oral drug delivery system. However, enhanced membrane fluidity and structural deformability may necessitate liposomal surface modification when facing the harsh environment of the gastrointestinal tract. In the present study, silica-coated flexible liposomes loaded with curcumin (CUR-SLs having poor water solubility as a model drug were prepared by a thin-film method with homogenization, followed by the formation of a silica shell by the sol-gel process. We systematically investigated the physical properties, drug release behavior, pharmacodynamics, and bioavailability of CUR-SLs. CUR-SLs had a mean diameter of 157 nm and a polydispersity index of 0.14, while the apparent entrapment efficiency was 90.62%. Compared with curcumin-loaded flexible liposomes (CUR-FLs without silica-coatings, CUR-SLs had significantly higher stability against artificial gastric fluid and showed more sustained drug release in artificial intestinal fluid as determined by in vitro release assays. The bioavailability of CUR-SLs and CUR-FLs was 7.76- and 2.35-fold higher, respectively, than that of curcumin suspensions. Silica coating markedly improved the stability of flexible liposomes, and CUR-SLs exhibited a 3.31-fold increase in bioavailability compared with CUR-FLs, indicating that silica-coated flexible liposomes may be employed as a potential carrier to deliver drugs with poor water solubility via the oral route with improved bioavailability.Keywords: silica, flexible liposome, oral bioavailability, curcumin

  2. Factors modulating bioavailability of quercetin-related flavonoids and the consequences of their vascular function.

    Science.gov (United States)

    Terao, Junji

    2017-09-01

    Nowadays dietary flavonoids attract much attention in the prevention of chronic diseases. Epidemiological and intervention studies strongly suggest that flavonoid intake has beneficial effects on vascular health. It is unlikely that flavonoids act as direct antioxidants, although oxidative stress profoundly contributes to vascular impairment leading to cardiovascular diseases. Instead, flavonoids may exert their function by tuning the cellular redox state to an adaptive response or tolerable stress. However, the optimum intake of flavonoids from supplements or diet has not been clarified yet, because a number of exogenous and endogenous factors modulating their bioavailability affect their vascular function. This review will focus on the current knowledge of the bioavailability and vascular function of quercetin as a representative of antioxidative flavonoids. Current intervention studies imply that intake of quercetin-rich onion improves vascular health. Onion may be superior to quercetin supplement from the viewpoint of quercetin bioavailability, probably because the food matrix enhances the intestinal absorption of quercetin. α-Glucosylation increases its bioavailability by elevating the accessibility to the absorptive cells. Prenylation may enhance bioaccumulation at the target site by increasing the cellular uptake. However, these chemical modifications do not guarantee health benefits to the vascular system. Dietary quercetin is exclusively present as their conjugated form in the blood stream. Quercetin may exert its vascular function as an aglycone within macrophage cells after inflammation-induced deconjugation and as conjugated metabolites by targeting endothelial cells. The relationship between the bioavailability and bio-efficacy should be clarified, to evaluate the vascular function of a wide variety of dietary flavonoids. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Effect of Sucralfate on the Relative Bioavailability of Enrofloxacin and Ciprofloxacin in Healthy Fed Dogs.

    Science.gov (United States)

    KuKanich, K; KuKanich, B; Guess, S; Heinrich, E

    2016-01-01

    Sucralfate impairs absorption of ciprofloxacin and other fluoroquinolones in humans, but no sucralfate-fluoroquinolone interaction has been reported in dogs. Veterinary formularies recommend avoiding concurrent administration of these medications, which might impact compliance, therapeutic success, and resistance selection from fluoroquinolones. To determine whether a drug interaction exists when sucralfate is administered to fed dogs concurrently with ciprofloxacin or enrofloxacin, and whether a 2 hour delay between fluoroquinolone and sucralfate affects fluoroquinolone absorption. Five healthy Greyhounds housed in a research colony. This was a randomized crossover study. Treatments included oral ciprofloxacin (C) or oral enrofloxacin (E) alone, each fluoroquinolone concurrently with an oral suspension of sucralfate (CS, ES), and sucralfate suspension 2 hours after each fluoroquinolone (C2S, E2S). Fluoroquinolone concentrations were evaluated using liquid chromatography with mass spectrometry. Drug exposure of ciprofloxacin was highly variable (AUC 5.52-22.47 h μg/mL) compared to enrofloxacin (AUC 3.86-7.50 h μg/mL). The mean relative bioavailability for ciprofloxacin and concurrent sucralfate was 48% (range 8-143%) compared to ciprofloxacin alone. Relative bioavailability of ciprofloxacin improved to 87% (range 37-333%) when sucralfate was delayed by 2 hours. By contrast, relative bioavailability for enrofloxacin and concurrent sucralfate was 104% (94-115%). A possible clinically relevant drug interaction for the relative bioavailability of ciprofloxacin with sucralfate was found. No significant difference in bioavailability was documented for enrofloxacin with sucralfate. Further research is warranted in fasted dogs and clinical cases requiring enrofloxacin or other approved fluoroquinolones in combination with sucralfate. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc on behalf of the American

  4. 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.

  5. 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.

  6. Increased asymmetric dimethylarginine in severe falciparum malaria: association with impaired nitric oxide bioavailability and fatal outcome.

    Directory of Open Access Journals (Sweden)

    Tsin W Yeo

    2010-04-01

    Full Text Available Asymmetrical dimethylarginine (ADMA, an endogenous inhibitor of nitric oxide synthase (NOS, is a predictor of mortality in critical illness. Severe malaria (SM is associated with decreased NO bioavailability, but the contribution of ADMA to the pathogenesis of impaired NO bioavailability and adverse outcomes in malaria is unknown. In adults with and without falciparum malaria, we tested the hypotheses that plasma ADMA would be: 1 increased in proportion to disease severity, 2 associated with impaired vascular and pulmonary NO bioavailability and 3 independently associated with increased mortality. We assessed plasma dimethylarginines, exhaled NO concentrations and endothelial function in 49 patients with SM, 78 with moderately severe malaria (MSM and 19 healthy controls (HC. Repeat ADMA and endothelial function measurements were performed in patients with SM. Multivariable regression was used to assess the effect of ADMA on mortality and NO bioavailability. Plasma ADMA was increased in SM patients (0.85 microM; 95% CI 0.74-0.96 compared to those with MSM (0.54 microM; 95%CI 0.5-0.56 and HCs (0.64 microM; 95%CI 0.58-0.70; p<0.001. ADMA was an independent predictor of mortality in SM patients with each micromolar elevation increasing the odds of death 18 fold (95% CI 2.0-181; p = 0.01. ADMA was independently associated with decreased exhaled NO (r(s = -0.31 and endothelial function (r(s = -0.32 in all malaria patients, and with reduced exhaled NO (r(s = -0.72 in those with SM. ADMA is increased in SM and associated with decreased vascular and pulmonary NO bioavailability. Inhibition of NOS by ADMA may contribute to increased mortality in severe malaria.

  7. 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.

  8. Selenium species-dependent toxicity, bioavailability and metabolic transformations in Caenorhabditis elegans.

    Science.gov (United States)

    Rohn, Isabelle; Marschall, Talke Anu; Kroepfl, Nina; Jensen, Kenneth Bendix; Aschner, Michael; Tuck, Simon; Kuehnelt, Doris; Schwerdtle, Tanja; Bornhorst, Julia

    2018-05-17

    The essential micronutrient selenium (Se) is required for various systemic functions, but its beneficial range is narrow and overexposure may result in adverse health effects. Additionally, the chemical form of the ingested selenium contributes crucially to its health effects. While small Se species play a major role in Se metabolism, their toxicological effects, bioavailability and metabolic transformations following elevated uptake are poorly understood. Utilizing the tractable invertebrate Caenorhabditis elegans allowed for an alternative approach to study species-specific characteristics of organic and inorganic Se forms in vivo, revealing remarkable species-dependent differences in the toxicity and bioavailability of selenite, selenomethionine (SeMet) and Se-methylselenocysteine (MeSeCys). An inverse relationship was found between toxicity and bioavailability of the Se species, with the organic species displaying a higher bioavailability than the inorganic form, yet being less toxic. Quantitative Se speciation analysis with HPLC/mass spectrometry revealed a partial metabolism of SeMet and MeSeCys. In SeMet exposed worms, identified metabolites were Se-adenosylselenomethionine (AdoSeMet) and Se-adenosylselenohomocysteine (AdoSeHcy), while worms exposed to MeSeCys produced Se-methylselenoglutathione (MeSeGSH) and γ-glutamyl-MeSeCys (γ-Glu-MeSeCys). Moreover, the possible role of the sole selenoprotein in the nematode, thioredoxin reductase-1 (TrxR-1), was studied comparing wildtype and trxr-1 deletion mutants. Although a lower basal Se level was detected in trxr-1 mutants, Se toxicity and bioavailability following acute exposure was indistinguishable from wildtype worms. Altogether, the current study demonstrates the suitability of C. elegans as a model for Se species dependent toxicity and metabolism, while further research is needed to elucidate TrxR-1 function in the nematode.

  9. Enhanced oral bioavailability of docetaxel in rats combined with myricetin: In situ and in vivo evidences.

    Science.gov (United States)

    Hao, Tianyun; Ling, Yunni; Wu, Meijuan; Shen, Yajing; Gao, Yu; Liang, Shujun; Gao, Yuan; Qian, Shuai

    2017-04-01

    The purpose of this study was to investigate the effect of myricetin on the pharmacokinetics of docetaxel in rats. In comparison to oral docetaxel alone (40mg/kg), the bioavailability of docetaxel could be significantly enhanced by 1.6-2.4-fold via oral co-administration with various flavonoids (apigenin, naringenin, baicalein, quercetin and myricetin) at a dosage of 10mg/kg, and myricetin showed the highest bioavailability improvement. Further pharmacokinetic studies demonstrated that the presence of myricetin (5-20mg/kg) enhanced both C max and AUC of docetaxel with the highest C max (162ng/mL, 2.3-fold) and relative bioavailability (244%) achieved at 10mg/kg of myricetin, while t 1/2 was not influenced. In order to explore the reasons for such bioavailability enhancement of docetaxel, rat in situ single-pass intestinal perfusion model and intravenous docetaxel co-administrated with oral myricetin were carried out. After combining with myricetin, the permeability coefficient (P blood ) of docetaxel based on its appearance in mesenteric blood was significantly increased up to 3.5-fold in comparison to that of docetaxel alone. Different from oral docetaxel, the intravenous pharmacokinetics of docetaxel was not affected by co-administration of myricetin, indicating the limited effect of myricetin on the elimination of docetaxel. The above findings suggested that the oral bioavailability enhancement of docetaxel via co-administration with myricetin might be mainly attributed to the enhanced absorption in gastrointestinal tract rather than modulating the elimination of docetaxel. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Effect of aggregation form on bioavailability of zeaxanthin in humans: a randomised cross-over study.

    Science.gov (United States)

    Hempel, Judith; Fischer, Anja; Fischer, Monique; Högel, Josef; Bosy-Westphal, Anja; Carle, Reinhold; Schweiggert, Ralf M

    2017-11-01

    Carotenoid bioavailability from plant and animal food is highly variable depending on numerous factors such as the physical deposition form of carotenoids. As the carotenoid zeaxanthin is believed to play an important role in eye and brain health, we sought to compare the human bioavailability of an H-aggregated with that of a J-aggregated deposition form of zeaxanthin encapsulated into identical formulation matrices. A randomised two-way cross-over study with sixteen participants was designed to compare the post-prandial bioavailability of an H-aggregated zeaxanthin and a J-aggregated zeaxanthin dipalmitate formulation, both delivering 10 mg of free zeaxanthin. Carotenoid levels in TAG-rich lipoprotein fractions were analysed over 9·5 h after test meal consumption. Bioavailability from the J-aggregated formulation (AUC=55·9 nmol h/l) was 23 % higher than from the H-aggregated one (AUC=45·5 nmol h/l), although being only marginally significant (P=0·064). Furthermore, the same formulations were subjected to an internationally recognised in vitro digestion protocol to reveal potential strengths and weaknesses of simulated digestions. In agreement with our human study, liberation of zeaxanthin from the J-aggregated formulation into the simulated duodenal fluids was superior to that from the H-aggregated form. However, micellization rate (bioaccessibility) of the J-aggregated zeaxanthin dipalmitate was lower than that of the H-aggregated zeaxanthin, being contradictory to our in vivo results. An insufficient ester cleavage during simulated digestion was suggested to be the root cause for these observations. In brief, combining our in vitro and in vivo observations, the effect of the different aggregation forms on human bioavailability was lower than expected.

  11. Mapping and defining sources of variability in bioavailable strontium isotope ratios in the Eastern Mediterranean

    Science.gov (United States)

    Hartman, Gideon; Richards, Mike

    2014-02-01

    The relative contributions of bedrock and atmospheric sources to bioavailable strontium (Sr) pools in local soils was studied in Northern Israel and the Golan regions through intensive systematic sampling of modern plants and invertebrates, to produce a map of modern bioavailable strontium isotope ratios (87Sr/86Sr) for regional reconstructions of human and animal mobility patterns. The study investigates sources of variability in bioavailable 87Sr/86Sr ratios, in particular the intra-and inter-site range of variation in plant 87Sr/86Sr ratios, the range of 87Sr/86Sr ratios of plants growing on marine sedimentary versus volcanic geologies, the differences between ligneous and non-ligneous plants with varying growth and water utilization strategies, and the relative contribution of atmospheric Sr sources from different soil and vegetation types and climatic zones. Results indicate predictable variation in 87Sr/86Sr ratios. Inter- and intra-site differences in bioavailable 87Sr/86Sr ratios average of 0.00025, while the range of 87Sr/86Sr ratios measured regionally in plants and invertebrates is 0.7090 in Pleistocene calcareous sandstone and 0.7074 in mid-Pleistocene volcanic pyroclast. The 87Sr/86Sr ratios measured in plants growing on volcanic bedrock show time dependent increases in atmospheric deposition relative to bedrock weathering. The 87Sr/86Sr ratios measured in plants growing on renzina soils depends on precipitation. The spacing between bedrock 87Sr/86Sr ratios and plants is highest in wet conditions and decreases in dry conditions. The 87Sr/86Sr ratios measured in plants growing on terra rossa soils is relatively constant (0.7085) regardless of precipitation. Ligneous plants are typically closer to bedrock 87Sr/86Sr ratios than non-ligneous plants. Since the bioavailable 87Sr/86Sr ratios currently measured in the region reflect a mix of both exogenous and endogenous sources, changes in the relative contribution of exogenous sources can cause variation

  12. 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

    Simulated intestinal media (SIM) containing bile salt (BS) and phospholipids (PL) with and without medium chain lipolytic products (MC-LP) or long chain lipolytic products (LC-LP) were developed to study the solubility of seocalcitol. Both MC-LP and LC-LP were studied in order to investigate...... 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...

  13. Effect of soil organic matter on antimony bioavailability after the remediation process

    International Nuclear Information System (INIS)

    Nakamaru, Yasuo Mitsui; Martín Peinado, Francisco José

    2017-01-01

    We evaluated the long-term (18 year) and short-term (4 weeks) changes of Sb in contaminated soil with SOM increase under remediation process. In the Aznalcóllar mine accident (1998) contaminated area, the remediation measurement implemented the Guadiamar Green Corridor, where residual pollution is still detected. Soils of the re-vegetated area (O2) with high pH and high SOM content, moderately re-vegetated area (O1) and unvegetated area (C) were sampled. Soil pH, CEC, SOM amount and soil Sb forms were evaluated. Soil Sb was measured as total, soluble, exchangeable, EDTA extractable, acid oxalate extractable, and pyro-phosphate extractable fractions. Further, the short-term effect of artificial organic matter addition was also evaluated with incubation study by adding compost to the sampled soil from C, O1 and O2 areas. After 4 weeks of incubation, soil chemical properties and Sb forms were evaluated. In re-vegetated area (O2), soil total Sb was two times lower than in unvegetated area (C); however, soluble, exchangeable, and EDTA extractable Sb were 2–8 times higher. The mobile/bioavailable Sb increase was also observed after 4 weeks of incubation with the addition of compost. Soluble, exchangeable, and EDTA extractable Sb was increased 2–4 times by compost addition. By the linear regression analysis, the significantly related factors for soluble, exchangeable, and EDTA extractable Sb values were pH, CEC, and SOM, respectively. Soluble Sb increase was mainly related to pH rise. Exchangeable Sb should be bound by SOM-metal complex and increased with CEC. EDTA extractable fraction should be increased with increase of SOM as SOM-Fe associated Sb complex. From these results, it was shown that increase of SOM under natural conditions or application of organic amendment under remediation process should increase availability of Sb to plants. - Highlights: • The effect of SOM on Sb availability was evaluated after the remediation process. • Increase in SOM raised

  14. 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

  15. The influence of particles on bioavailability and toxicity of pesticides in surface water.

    Science.gov (United States)

    Knauer, Katja; Homazava, Nadzeya; Junghans, Marion; Werner, Inge

    2017-07-01

    Environmental risk assessment is an essential part of the approval process for pesticides. Exposure concentrations are compared with ecotoxicological data obtained from standardized laboratory studies and, if available, from field studies to determine the risk of a substance or formulation for aquatic communities. Predicted concentrations in surface waters are derived using, for example, the European FOrum for the Co-ordination of pesticide fate models and their USe (FOCUS) or the German Exposit models, which distinguish between exposure to dissolved and particle-associated pesticide concentrations, because the dissolved concentration is thought to be the best predictor of bioavailability and toxicity. Water and particle-associated concentrations are estimated based on the organic carbon-water partitioning coefficient (K OC ). This review summarizes published information on the influence of natural suspended solids on bioavailability and toxicity of pesticides to aquatic organisms (algae, invertebrates and fish), and the value of log K OC and log K OW (octanol-water coefficient) as sole predictors of the bioavailable fraction is discussed. The information showed that: 1) the quality and origin of suspended solids played an important role in influencing pesticide bioavailability and toxicity; 2) a decrease in toxicity due to the presence of suspended solids was shown only for pyrethroid insecticides with log K OW greater than 5, but the extent of this reduction depended on particle concentration and size, and potentially also on the ecotoxicological endpoint; 3) for pesticides with a log K OW less than 3 (e.g., triazines, carbamates, and organophosphates), the impact of particles on bioavailability and toxicity is small and species dependent; and 4) pesticide bioavailability is greatly influenced by the test species and their physiology (e.g., feeding behavior or digestion). We conclude that exposure of aquatic organisms to pesticides and environmental risk of many

  16. 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.

  17. Quantifying the effect of sorption and bioavailability of hydrophobic organic contaminants

    International Nuclear Information System (INIS)

    Zhang, W.; Bouwer, E.; Cunningham, A.

    1994-01-01

    In-situ bioremediation has been applied successfully at a few sites. Several restrictions presently exist which could greatly limit the effectiveness of this promising technology. Hydrophobic organic contaminants tend to sorb onto soil. However, microorganisms are most effective in utilizing substrates from the aqueous phase. Sorption tends to separate the direct contact between microorganisms and contaminants necessary for biodegradation to occur. A series of experiments, which represented scenarios with fast sorption/desorption, slow sorption/desorption, mass transfer across boundary layer and mass transfer within attached microorganisms (biofilm), was conducted to demonstrate the concentration effect and the mass transfer effect. A method has been developed to quantify bioavailability of organic contaminants in aquatic environments. Bioavailability Factor (B f ), a dimensionless parameter derived from mathematical models and verified by experimental results, has been formulated to describe the impact of equilibrium sorption, nonequilibrium sorption, and mass transfer processes on the rate and extent of biodegradation of petroleum hydrocarbons

  18. 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.

  19. The tomato sauce making process affects the bioaccessibility and bioavailability of tomato phenolics: a pharmacokinetic study.

    Science.gov (United States)

    Martínez-Huélamo, Miriam; Tulipani, Sara; Estruch, Ramón; Escribano, Elvira; Illán, Montserrat; Corella, Dolores; Lamuela-Raventós, Rosa M

    2015-04-15

    Tomato sauce is the most commonly consumed processed tomato product worldwide, but very little is known about how the manufacturing process may affect the phenolic composition and bioavailability after consumption. In a prospective randomised, cross-over intervention study, we analysed the plasma and urinary levels of tomato phenolic compounds and their metabolites after acute consumption of raw tomatoes and tomato sauce, enriched or not with refined olive oil during production. Respectively, eleven and four phenolic metabolites were found in urine and plasma samples. The plasma concentration and urinary excretion of naringenin glucuronide were both significantly higher after the consumption of tomato sauce than raw tomatoes. The results suggest that the mechanical and thermal treatments during tomato sauce manufacture may help to deliver these potentially bioactive phenolics from the food matrix more effectively than the addition of an oil component, thus increasing their bioavailability. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Nutritional and Acquired Deficiencies in Inositol Bioavailability. Correlations with Metabolic Disorders

    Directory of Open Access Journals (Sweden)

    Simona Dinicola

    2017-10-01

    Full Text Available Communities eating a western-like diet, rich in fat, sugar and significantly deprived of fibers, share a relevant increased risk of both metabolic and cancerous diseases. Even more remarkable is that a low-fiber diet lacks some key components—as phytates and inositols—for which a mechanistic link has been clearly established in the pathogenesis of both cancer and metabolic illness. Reduced bioavailability of inositol in living organisms could arise from reduced food supply or from metabolism deregulation. Inositol deregulation has been found in a number of conditions mechanistically and epidemiologically associated to high-glucose diets or altered glucose metabolism. Indeed, high glucose levels hinder inositol availability by increasing its degradation and by inhibiting both myo-Ins biosynthesis and absorption. These underappreciated mechanisms may likely account for acquired, metabolic deficiency in inositol bioavailability.

  1. Regulation of the Bioavailability of TGF-β and TGF-β-Related Proteins

    Science.gov (United States)

    Robertson, Ian B.; Rifkin, Daniel B.

    2016-01-01

    The bioavailability of members of the transforming growth factor β (TGF-β) family is controlled by a number of mechanisms. Bona fide TGF-β is sequestered into the matrix in a latent state and must be activated before it can bind to its receptors. Here, we review the molecules and mechanisms that regulate the bioavailability of TGF-β and compare these mechanisms with those used to regulate other TGF-β family members. We also assess the physiological significance of various latent TGF-β activators, as well as other extracellular modulators of TGF-β family signaling, by examining the available in vivo data from knockout mouse models and other biological systems. PMID:27252363

  2. Strategies to enhance the bioavailability of curcumin: a potential antitumor drug

    Science.gov (United States)

    Kumar, Abhishek; Chittigori, Joshna; Li, Lian; Samuelson, Lynne; Sandman, Daniel; Kumar, Jayant

    2012-02-01

    Curcumin is a polyphenol which has elicited considerable interest for its antioxidant and anti tumor properties. Although curcumin may be used as potential therapeutic drug, it is very sparingly soluble in water which makes it less bioavailable under physiological conditions. We report two approaches to make curcumin more bioavailable. The first approach involves fabricating colloidal dispersions of curcumin in the range of tens of nanometers. The second approach involves functionalization of curcumin with polyethylene glycol (PEG) to render it water dispersible or soluble. Since curcumin is a fluorescent molecule as well as a potential drug, its interactions with cells have been investigated using one and two photon confocal fluorescence imaging. We have also observed strong interaction between curcumin and metal ions, which may have physiological implications.

  3. 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...... of these fatty acids, whereas diverse results have been reported from long-term studies. Therefore more studies are encouraged to clarify the long-term effects....

  4. Influence of eutrophication on metal bioaccumulation and oral bioavailability in oysters, Crassostrea angulata.

    Science.gov (United States)

    Li, Shun-Xing; Chen, Li-Hui; Zheng, Feng-Ying; Huang, Xu-Guang

    2014-07-23

    Oysters (Crassostrea angulata) are often exposed to eutrophication. However, how these exposures influence metal bioaccumulation and oral bioavailability (OBA) in oysters is unknown. After a four month field experimental cultivation, bioaccumulation factors (BAF) of metals (Fe, Cu, As, Cd, and Pb) from seawater to oysters and metal oral bioavailability in oysters by bionic gastrointestinal tract were determined. A positive effect of macronutrient (nitrate N and total P) concentration in seawater on BAF of Cd in oysters was observed, but such an effect was not significant for Fe, Cu, Pb, and As. Only OBA of As was significantly positively correlated to N and P contents. For Fe, OBA was negatively correlated with N. The regular variation of the OBA of Fe and As may be due to the effect of eutrophication on the synthesis of metal granules and heat-stable protein in oysters, respectively.

  5. 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.

  6. Methods to assess bioavailability of hydrophobic organic contaminants: Principles, operations, and limitations.

    Science.gov (United States)

    Cui, Xinyi; Mayer, Philipp; Gan, Jay

    2013-01-01

    Many important environmental contaminants are hydrophobic organic contaminants (HOCs), which include PCBs, PAHs, PBDEs, DDT and other chlorinated insecticides, among others. Owing to their strong hydrophobicity, HOCs have their final destination in soil or sediment, where their ecotoxicological effects are closely regulated by sorption and thus bioavailability. The last two decades have seen a dramatic increase in research efforts in developing and applying partitioning based methods and biomimetic extractions for measuring HOC bioavailability. However, the many variations of both analytical methods and associated measurement endpoints are often a source of confusion for users. In this review, we distinguish the most commonly used analytical approaches based on their measurement objectives, and illustrate their practical operational steps, strengths and limitations using simple flowcharts. This review may serve as guidance for new users on the selection and use of established methods, and a reference for experienced investigators to identify potential topics for further research. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Eudragit L/HPMCAS blend enteric-coated lansoprazole pellets: enhanced drug stability and oral bioavailability.

    Science.gov (United States)

    Fang, Yu; Wang, Guozheng; Zhang, Rong; Liu, Zhihua; Liu, Zhenghua; Wu, Xiaohui; Cao, Deying

    2014-06-01

    The objectives of the present work were to use blends of Eudragit L and hydroxypropyl methylcellulose acetate succinate (HPMCAS) as enteric film coatings for lansoprazole (LSP) pellets. The enteric-coated pellets were prepared with a fluid-bed coater. The influence of the blend ratio, type of plasticizer, plasticizer level, coating level, and curing conditions on gastric stability in vitro drug release and drug stability was evaluated. Furthermore, the bioavailability of the blend-coated pellets in beagle dogs was also performed. The blend-coated pellets exhibited significant improvement of gastric stability and drug stability compared to the pure polymer-coated pellets. Moreover, the AUC values of blend-coated pellets were greater than that of the pure polymer-coated pellets. It was concluded that the using blends of Eudragit L and HPMCAS as enteric film coatings for LSP pellets improved the drug stability and oral bioavailability.

  8. 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....

  9. Bioavailability of iron to rats from processed soybean fractions determined by intrinsic and extrinsic labeling techniques

    International Nuclear Information System (INIS)

    Weaver, C.M.; Nelson, N.; Elliott, J.G.

    1984-01-01

    Intrinsic and extrinsic labeling techniques were used to measure iron bioavailability from soybean fractions (isolated soy protein, defatted flour, soy hulls, insoluble material and whey) by iron-depleted and non-iron-depleted rats. As expected, absorption of iron was higher in the iron-depleted than in the non-iron-depleted rats. In the iron-depleted group, significantly more iron was absorbed from soy whey than from other fractions. No other significant difference in iron absorption associated with iron source was observed. The higher absorption rate of iron from whey by the iron-depleted rats probably was related to a lower quantity of food consumed during the test meal by this group. Intrinsic and extrinsic labeling techniques produced similar assessments of bioavailability of iron

  10. [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.

  11. The influence of extracellular superoxide on iron redox chemistry and bioavailability to aquatic microorganisms

    Directory of Open Access Journals (Sweden)

    Andrew eRose

    2012-04-01

    Full Text Available Superoxide, the one-electron reduced form of dioxygen, is produced in the extracellular milieu of aquatic microbes through a range of abiotic chemical processes and also by microbes themselves. Due to its ability to promote both oxidative and reductive reactions, superoxide may have a profound impact on the redox state of iron, potentially influencing iron solubility, complex speciation and bioavailability. The interplay between iron, superoxide and oxygen may also produce a cascade of other highly reactive transients in oxygenated natural waters. For microbes, the overall effect of reactions between superoxide and iron may be deleterious or beneficial, depending on the organism and its chemical environment. Here I critically discuss recent advances in understanding: (i sources of extracellular superoxide in natural waters, with a particular emphasis on microbial generation; (ii the chemistry of reactions between superoxide and iron; and (iii the influence of these processes on iron bioavailability and microbial iron nutrition.

  12. N,N'-dihydroxyamidines: a new prodrug principle to improve the oral bioavailability of amidines.

    Science.gov (United States)

    Reeh, Christiane; Wundt, Judith; Clement, Bernd

    2007-12-27

    N, N'-dihydroxybenzamdine represents a model compound for a new prodrug principle to improve the oral bioavailability of drugs containing amidine functions. The activation of the prodrug could be demonstrated in vitro by porcine and human subcellular enzyme fractions, the mitochondrial benzamidoxime reducing system, and porcine hepatocytes. In vivo, the bioavailability of benzamidine after oral application of N, N'-dihydroxybenzamidine was about 91% and exceeded that of benzamidine after oral application of benzamidoxime, being about 74% (Liu, L.; Ling, Y.; Havel, C.; Bashnick, L.; Young, W.; Rai, R.; Vijaykumar, D.; Riggs, J. R.; Ton, T.; Shaghafi, M.; Graupe, D.; Mordenti, J.; Sukbuntherng, J. Species comparison of in vitro and in vivo conversion of five N-hydroxyamidine prodrugs of fVIIA inhibitors to their corresponding active amidines. Presented at the 13th North America ISSX Meeting, Maui, HI, 2005).

  13. Radionuclides in produced water from Norwegian oil and gas installations - concentrations and bioavailability

    International Nuclear Information System (INIS)

    Eriksen, D.Oe.; Sidhu, R.; Stralberg, E.; Iden, K.I.; Hylland, K.; Ruus, A.; Roeyset, O.; Berntssen, M.H.G.; Rye, H.

    2006-01-01

    Substantial amounts of produced water, containing elevated levels of radionuclides (mainly 226 Ra and 228 Ra) are discharged to the sea as a result of oil and gas production on the Norwegian Continental Shelf. So far no study has assessed the potential radiological effects on marine biota in connection with radionuclide discharges to the North Sea. The main objective of the project is to establish radiological safe discharge limits for radium, lead and polonium associated with other components in produced water from oil and gas installations on the Norwegian continental shelf. This study reports results indicating that the presence of added chemicals such as scale inhibitors in produced water has a marked influence on the formation of radium and barium sulphates when produced water is mixed with sea water. Thus, the mobility and bioavailability of radium (and barium) will be larger than anticipated. Also, the bioavailability of food-borne radium is shown to increase due to presence of such chemicals. (author)

  14. Radionuclides in produced water from Norwegian oil and gas installations — Concentrations and bioavailability

    Science.gov (United States)

    Eriksen, D. Ø.; Sidhu, R.; Strålberg, E.; Iden, K. I.; Hylland, K.; Ruus, A.; Røyset, O.; Berntssen, M. H. G.; Rye, H.

    2006-01-01

    Substantial amounts of produced water, containing elevated levels of radionuclides (mainly 226Ra and 228Ra) are discharged to the sea as a result of oil and gas production on the Norwegian Continental Shelf. So far no study has assessed the potential radiological effects on marine biota in connection with radionuclide discharges to the North Sea. The main objective of the project is to establish radiological safe discharge limits for radium, lead and polonium associated with other components in produced water from oil and gas installations on the Norwegian continental shelf. This study reports results indicating that the presence of added chemicals such as scale inhibitors in produced water has a marked influence on the formation of radium and barium sulphates when produced water is mixed with sea water. Thus, the mobility and bioavailability of radium (and barium) will be larger than anticipated. Also, the bioavailability of food-borne radium is shown to increase due to presence of such chemicals.

  15. Influence of organic matter transformations on the bioavailability of heavy metals in a sludge base compost

    International Nuclear Information System (INIS)

    Molina, M. J.; Ingelmo, F.; Soriano, M. D.; Gallardo, A.; Lapena, L.

    2009-01-01

    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)

  16. 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)

  17. Hydrological regime and salinity alter the bioavailability of Cu and Zn in wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Speelmans, M. [Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, B-9000 Ghent (Belgium); Lock, K., E-mail: koen.lock@UGent.b [Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, B-9000 Ghent (Belgium); Vanthuyne, D.R.J. [Laboratory of Analytical Chemistry and Applied Ecochemistry, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Hendrickx, F. [Terrestrial Ecology Unit (TEREC), Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent (Belgium); Du Laing, G.; Tack, F.M.G. [Laboratory of Analytical Chemistry and Applied Ecochemistry, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Janssen, C.R. [Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, B-9000 Ghent (Belgium)

    2010-05-15

    In the context of the European Water Framework Directive, controlled flooding of lowlands is considered as a potential water management strategy to minimise the risk of flooding of inhabited areas. However, due to historical pollution and overbank sedimentation, metal levels are elevated in most wetlands, which can cause adverse effects on the ecosystem's dynamics. Additionally, salinity affects the bioavailability of metals present or imported into these systems. The effect of different flooding regimes and salinity exposure scenarios (fresh- and brackish water conditions) on Cu and Zn accumulation in the oligochaete Tubifex tubifex (Mueller, 1774) was examined. Metal mobility was closely linked to redox potential, which is directly related to the prevalent hydrological regime. Flooded, and thus more reduced, conditions minimized the availability of metals, while oxidation of the substrates during a drier period was associated with a rapid increase of metal availability and accumulation in the oligochaetes. - Metal bioavailability in wetlands.

  18. 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

    The present paper summarizes the current state of knowledge on cereal phytase that are particular relevant for improving mineral and phosphate bio-availability. Phytases can initiate the hydrolysis of phytate, the main storage form of phosphate in cereals and the major anti-nutritional factor...... 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...... wheat, barley and rye whereas non-Triticeae cereals such as maize and rice have very little MGPA. Recent studies have determined the evolutionary relationships of phytases in Triticeae and non-Triticeae and highlighted the importance of the purple acid phosphatase phytases (PAPhys). In the Triticeae...

  19. Cubic phase nanoparticles for sustained release of ibuprofen: formulation, characterization, and enhanced bioavailability study

    Science.gov (United States)

    Dian, Linghui; Yang, Zhiwen; Li, Feng; Wang, Zhouhua; Pan, Xin; Peng, Xinsheng; Huang, Xintian; Guo, Zhefei; Quan, Guilan; Shi, Xuan; Chen, Bao; Li, Ge; Wu, Chuanbin

    2013-01-01

    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 ibuprofen-loaded cubic nanoparticles provide a promising carrier candidate with an efficient drug delivery for therapeutic treatment. PMID:23468008

  20. Influence of particle characteristics and organic matter content on the bioavailability and bioaccumulation of pyrene by clams

    International Nuclear Information System (INIS)

    Verrengia Guerrero, N.R.; Taylor, M.G.; Wider, E.A.; Simkiss, K.

    2003-01-01

    An experimental model with artificial particles and humic acids describes bioavailability of sediment-bound pyrene to clams. - Hydrophobic chemicals are known to associate with sediment particles including those from both suspended particulate matter and bottom deposits. The complex and variable composition of natural particles makes it very difficult therefore, to predict the bioavailability of sediment-bound contaminants. To overcome these problems we have previously devised a test system using artificial particles, with or without humic acids, for use as an experimental model of natural sediments. In the present work we have applied this experimental technique to investigate the bioavailability and bioaccumulation of pyrene by the freshwater fingernail clam Sphaerium corneum. The uptake and accumulation of pyrene in clams exposed to the chemical in the presence of a sample of natural sediment was also investigated. According to the results obtained, particle surface properties and organic matter content are the key factors for assessing the bioavailability and bioaccumulation of pyrene by clams

  1. 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.

  2. 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.

  3. EFFECT OF CONTAMINANT AND ORGANIC MATTER BIOAVAILABILITY ON THE MICROBIAL DEHALOGENATION OF SEDIMENT-BOUND CHLOROBENZENES. (R825513C007)

    Science.gov (United States)

    The extent of reductive dechlorination occurring in contaminated, estuarine sediments was investigated. Contaminant and organic matter bioavailability and their effect on the reductive dechlorination of sediment-bound chlorobenzenes was the main focus of the work presented her...

  4. 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

    2006-06-01

    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.

  5. In Vitro Bioavailability of Calcium, Magnesium, Iron, Zinc, and Copper from Gluten-Free Breads Supplemented with Natural Additives.

    Science.gov (United States)

    Regula, J; Cerba, A; Suliburska, J; Tinkov, A A

    2018-03-01

    The aim of this study was to measure the content of calcium, magnesium, iron, zinc, and copper and determine the bioavailability of these ingredients in gluten-free breads fortified with milk and selected seeds. Due to the increasing prevalence of celiac disease and mineral deficiencies, it has become necessary to produce food with higher nutritional values which maintains the appropriate product characteristics. This study was designed for gluten-free breads fortified with milk and seeds such as flax, poppy, sunflower seeds, pumpkin seeds or nuts, and flour with amaranth. Subsequently, digestion was performed in vitro and the potential bioavailability of the minerals was measured. In the case of calcium, magnesium, iron, and copper, higher bioavailability was observed in rice bread, and, in the case of copper and zinc, in buckwheat bread. This demonstrated a clear increase in bioavailability of all the minerals when the bread were enriched. However, satisfactory results are obtained only for the individual micronutrients.

  6. 21 CFR 320.26 - Guidelines on the design of a single-dose in vivo bioavailability or bioequivalence study.

    Science.gov (United States)

    2010-04-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE BIOAVAILABILITY AND BIOEQUIVALENCE... test product and the reference material should be administered to subjects in the fasting state, unless...

  7. Incorporating bioavailability into management limits for copper in sediments contaminated by antifouling paint used in aquaculture.

    Science.gov (United States)

    Simpson, Stuart L; Spadaro, David A; O'Brien, Dom

    2013-11-01

    Although now well embedded within many risk-based sediment quality guideline (SQG) frameworks, contaminant bioavailability is still often overlooked in assessment and management of contaminated sediments. To optimise management limits for metal contaminated sediments, we assess the appropriateness of a range methods for modifying SQGs based on bioavailability considerations. The impairment of reproduction of the amphipod, Melita plumulosa, and harpacticoid copepod, Nitocra spinipes, was assessed for sediments contaminated with copper from antifouling paint, located below aquaculture cages. The measurement of dilute acid-extractable copper (AE-Cu) was found to provide the most useful means for monitoring the risks posed by sediment copper and setting management limits. Acid-volatile sulfide was found to be ineffective as a SQG-modifying factor as these organisms live mostly at the more oxidised sediment water interface. SQGs normalised to %-silt/organic carbon were effective, but the benefits gained were too small to justify this approach. The effectiveness of SQGs based on AE-Cu was attributed to a small portion of the total copper being present in potentially bioavailable forms (typicallycopper was likely present as paint flakes in the form of copper (I) oxide, the active ingredient of the antifoulant formulation. While the concentrations of paint-associated copper are very high in some sediments, as the transformation of this form of copper to AE-Cu appears slow, monitoring and management limits should assess the more bioavailable AE-Cu forms, and further efforts be made to limit the release of paint particles into the environment. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  8. Design and development of microemulsion drug delivery system of acyclovir for improvement of oral bioavailability

    OpenAIRE

    Ghosh, Pradip Kumar; Majithiya, Rita J.; Umrethia, Manish L.; Murthy, Rayasa S. R.

    2006-01-01

    The main purpose of this work was to develop an oral microemulsion formulation for enhancing the bioavailability of acyclovir. A Labrafac-based microemulsion formulation with Labrasol as surfactant and Plurol Oleique as cosurfactant was developed for oral delivery of acyclovir. Phase behavior and solubilization capacity of the microemulsion system were characterized, and in vivo oral absorption of acyclovir from the microemulsion was investigated in rats. A single isotropic region, which was ...

  9. 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.

  10. Oral administration of amphotericin B nanoparticles: antifungal activity, bioavailability and toxicity in rats.

    Science.gov (United States)

    Radwan, Mahasen A; AlQuadeib, Bushra T; Šiller, Lidija; Wright, Matthew C; Horrocks, Benjamin

    2017-11-01

    Amphotericin B (AMB) is used most commonly in severe systemic life-threatening fungal infections. There is currently an unmet need for an efficacious (AMB) formulation amenable to oral administration with better bioavailability and lower nephrotoxicity. Novel PEGylated polylactic-polyglycolic acid copolymer (PLGA-PEG) nanoparticles (NPs) formulations of AMB were therefore studied for their ability to kill Candida albicans (C. albicans). The antifungal activity of AMB formulations was assessed in C. albicans. Its bioavalability was investigated in nine groups of rats (n = 6). Toxicity was examined by an in vitro blood hemolysis assay, and in vivo nephrotoxicity after single and multiple dosing for a week by blood urea nitrogen (BUN) and plasma creatinine (PCr) measurements. The MIC of AMB loaded to PLGA-PEG NPs against C. albicans was reduced two to threefold compared with free AMB. Novel oral AMB delivery loaded to PLGA-PEG NPs was markedly systemically available compared to Fungizone® in rats. The addition of 2% of GA to the AMB formulation significantly (p bioavailability from 1.5 to 10.5% and the relative bioavailability was > 790% that of Fungizone®. The novel AMB formulations showed minimal toxicity and better efficacy compared to Fungizone®. No nephrotoxicity in rats was detected after a week of multiple dosing of AMB NPs based on BUN and PCr, which remained at normal levels. An oral delivery system of AMB-loaded to PLGA-PEG NPs with better efficacy and minimal toxicity was formulated. The addition of glycyrrhizic acid (GA) to AMB NPs formulation resulted in a significant oral absorption and improved bioavailability in rats.

  11. Preparation, characterization and bioavailability by oral administration of O/W curcumin nanoemulsions stabilized with lysophosphatidylcholine.

    Science.gov (United States)

    Chávez-Zamudio, Rubi; Ochoa-Flores, Angélica A; Soto-Rodríguez, Ida; Garcia-Varela, Rebeca; García, Hugo Sergio

    2017-09-20

    Curcumin is the main and most abundant bioactive component in Curcuma longa L. with documented properties in the prevention and treatment of chronic degenerative and infectious diseases. However, curcumin has low solubility in aqueous media, hence low bioavailability when administered orally. The use of nanoemulsions as carriers can provide a partial solution to bioavailability restrictions. In our study, O/W nanoemulsions of curcumin were prepared using lysophosphatidylcholine, a phospholipid with proven emulsification capacity; nevertheless, such qualities have not been previously reported in the preparation of nanoemulsions. Lysophosphatidylcholine was obtained by enzymatic removal of one fatty acid residue from phosphatidylcholine. The objective of our work was to formulate stable curcumin nanoemulsions and evaluate their bioavailability in BALB/c mice plasma after oral administration. Formulated nanoemulsions had a droplet size mean of 154.32 ± 3.10 nm, a polydispersity index of 0.34 ± 0.07 and zeta potential of -10.43 ± 1.10 mV; stability was monitored for 12 weeks. Lastly, in vivo pharmacokinetic parameters, using BALB/c mice, were obtained; namely, C max of 610 ± 65.0 μg mL -1 and T max of 2 h. Pharmacokinetic data revealed a higher bioavailability of emulsified as opposed to free curcumin. Research regarding other potential emulsifiers that may provide better health benefits and carry nano-encapsulated bioactive compounds more effectively, is necessary. This study provides important data on the preparation and design of nanoencapsulated Curcumin using lysophosphatidylcholine as an emulsifier.

  12. Relative bioavailability of micronized, dispersible ferric pyrophosphate added to an apple juice drink.

    Science.gov (United States)

    Roe, Mark A; Collings, Rachel; Hoogewerff, Jurian; Fairweather-Tait, Susan J

    2009-03-01

    Food iron fortification is a sustainable and relatively simple strategy to reduce/prevent iron deficiency but is a challenge for the food industry because of possible adverse organoleptic changes caused by the added iron. A micronized dispersible ferric pyrophosphate, trademarked as SunActive Fe, has recently been developed. SunActive Fe has a small particle size, is water soluble and may be suitable for fortifying liquid products. To determine the relative bioavailability of SunActive Fe and its suitability for addition to pure apple juice. Iron absorption from SunActive Fe added to pure apple juice (Minute Maid) was compared with absorption from ferrous sulphate, a highly bioavailable form of iron, in 15 women with relatively low iron stores. Both forms of iron were enriched with an iron stable isotope and iron absorption from the apple juice drinks was calculated from the isotopic enrichment of red blood cells 14 days after the last test meal. Although mean absorption of iron from SunActive Fe was significantly lower than from ferrous sulphate (5.5% compared with 9.1%), the mean bioavailability of SunActive Fe iron relative to ferrous sulphate was 0.6, indicating that it is a good source of bioavailable iron. Iron Absorption from SunActive Fe was positively correlated (r = 0.97, P = 0.01) with absorption from ferrous sulphate, and negatively correlated with serum ferritin concentration (ferrous sulphate r = -0.81, P apple juice and is a potentially useful fortificant for liquid food products.

  13. Milk does not affect the bioavailability of cocoa powder flavonoid in healthy human.

    Science.gov (United States)

    Roura, Elena; Andrés-Lacueva, Cristina; Estruch, Ramon; Mata-Bilbao, M Lourdes; Izquierdo-Pulido, Maria; Waterhouse, Andrew L; Lamuela-Raventós, Rosa M

    2007-01-01

    The beneficial effects of cocoa polyphenols depend on the amount consumed, their bioavailability and the biological activities of the formed conjugates. The food matrix is one the factors than can affect their bioavailability, but previous studies have concluded rather contradictory results about the effect of milk on the bioavailability of polyphenols. The objective was to evaluate the possible interaction of milk on the absorption of (-)-epicatechin ((-)-Ec) from cocoa powder in healthy humans. 21 volunteers received three interventions in a randomized crossover design with a 1-week interval (250 ml of whole milk (M-c) (control), 40 g of cocoa powder dissolved in 250 ml of whole milk (CC-M), and 40 g of cocoa powder dissolved with 250 ml of water (CC-W)). Quantification of (-)-Ec in plasma was determined by LC-MS/MS analysis prior to a solid-phase extraction procedure. 2 h after the intake of the two cocoa beverages, (-)-Ec-glucuronide was the only (-)-Ec metabolite detected, showing a mean (SD) plasma concentration of 330.44 nmol/l (156.1) and 273.7 nmol/l (138.42) for CC-W and CC-M, respectively (p = 0.076). Cocoa powder dissolved in milk as one of the most common ways of cocoa powder consumption seems to have a negative effect on the absorption of polyphenols; however, statistical analyses have shown that milk does not impair the bioavailability of polyphenols and thus their potential beneficial effect in chronic and degenerative disease prevention. (c) 2007 S. Karger AG, Basel

  14. 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 [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Lii, Chong-Kuei [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

  15. Bioavailability of andrographolide and protection against carbon tetrachloride-induced oxidative damage in rats

    International Nuclear Information System (INIS)

    Chen, Haw-Wen; Huang, Chin-Shiu; Li, Chien-Chun; Lin, Ai-Hsuan; Huang, Yu-Ju; Wang, Tsu-Shing; Yao, Hsien-Tsung; Lii, Chong-Kuei

    2014-01-01

    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 4 ) at day 6. Andrographolide pretreatment suppressed CCl 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 in

  16. 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

  17. Selenium bioavailability from naturally produced high-selenium peas and oats in selenium-deficient rats.

    Science.gov (United States)

    Yan, Lin; Johnson, LuAnn K

    2011-06-08

    This study determined the bioavailability of selenium (Se) from yellow peas and oats harvested from the high-Se soil of South Dakota, United States. The Se concentrations were 13.5 ± 0.2 and 2.5 ± 0.1 mg/kg (dry weight) for peas and oats, respectively. Male weanling Sprague-Dawley rats were depleted of Se by feeding them a 30% Torula yeast-based diet (4.1 μg Se/kg) for 56 days, and then they were replenished with Se for an additional 50 days by feeding them the same diet supplemented with 20, 30, or 40 μg Se/kg from peas or oats, respectively. Selenium bioavailability was determined on the basis of the restoration of Se-dependent enzyme activities and tissue Se concentrations in Se-depleted rats, comparing those responses for yellow peas and oats to those for l-selenomethionine (SeMet; used as a reference) by using a slope-ratio method. Dietary supplementation with peas or oats resulted in linear or log-linear, dose-dependent increases in glutathione peroxidase activities in blood and liver and in thioredoxin reductase activity in liver. Supplementation with peas or oats resulted in linear or log-linear, dose-dependent increases in Se concentrations of plasma, liver, gastrocnemius muscle, and kidneys. The overall bioavailability was approximately 88% for Se from yellow peas and 92% from oats, compared to SeMet. It was concluded that Se from naturally produced high-Se yellow peas or oats is highly bioavailable in this model and that these high-Se foods may be a good dietary source of Se.

  18. Dietary proanthocyanidins: Occurrence, dietary intake, bioavailability, and protection against cardiovascular disease

    DEFF Research Database (Denmark)

    Rasmussen, S. E.; Frederiksen, H.; Krogholm, Kirstine Suszkiewicz

    2005-01-01

    The French have one of the lowest incidences of coronary heart disease in the Western world despite a diet with a relatively high fat content. This phenomenon that has puzzled researchers worldwide for more than a decade is known as the 'French paradox' and has been linked to the high consumption......, the occurrence, the daily intake from foods, the bioavailability and metabolism, and the evidence for a protective effect against cardiovascular diseases....

  19. The Effect of Soil Properties on Metal Bioavailability: Field Scale Validation to Support Regulatory Acceptance

    Science.gov (United States)

    2014-06-01

    blood Pb. The default bioavailability assumptions in EPA’s blood-Pb model are 50% for food and water and 30% for soil, thus yielding a relative...in the recalcitrant residual fraction and was not available to maize grown in the soils. When Zn was added to the soil, the calcium (Ca...this study will significantly help bridge this data gap . Publications and abstracts related to this study are described below in Table 19. Table

  20. Diagenesis and bioavailability of mercury in the contaminated sediments of Ulhas Estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Ram, A.; Borole, D.V.; Rokade, M.A.; Zingde, M.D.

    ), and determining the retention of particle-bound elements in the sedimentary record (Shaw et al., 1990). Bioavailable metals are defined as metals in such a biologically available chemical state that they can be taken up by an organism and can react with its..., characterized by particular hydrodynamics and physical, 3 chemical and biological conditions. The estuary can be considered a natural chemical reactor in which material is constantly imported, transformed and exported. It is heavily affected by anthropogenic...

  1. Optimization of caseinate-coated simvastatin-zein nanoparticles: improved bioavailability and modified release characteristics.

    Science.gov (United States)

    Ahmed, Osama A A; Hosny, Khaled M; Al-Sawahli, Majid M; Fahmy, Usama A

    2015-01-01

    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 from the optimized SMV-zein formulation, by fourfold relative to SMV suspension. Formulation of caseinate-coated SMV-zein nanoparticles improves the pharmacokinetic profile and bioavailability of SMV. Accordingly, improved hypolipidemic activities for longer duration could be achieved. In addition, the reduced dosage rate of SMV-zein nanoparticles improves patient tolerability and compliance.

  2. Bioavailability of morphine, methadone, hydromorphone, and oxymorphone following buccal administration in cats.

    Science.gov (United States)

    Pypendop, B H; Ilkiw, J E; Shilo-Benjamini, Y

    2014-06-01

    Buccal administration of buprenorphine is commonly used to treat pain in cats. It has been argued that absorption of buprenorphine through the buccal mucosa is high, in part due to its pKa of 8.24. Morphine, methadone, hydromorphone, and oxymorphone have a pKa between 8 and 9. This study characterized the bioavailability of these drugs following buccal administration to cats. Six healthy adult female spayed cats were used. Buccal pH was measured prior to drug administration. Morphine sulfate, 0.2 mg/kg IV or 0.5 mg/kg buccal; methadone hydrochloride, 0.3 mg/kg IV or 0.75 mg/kg buccal; hydromorphone hydrochloride, 0.1 mg/kg IV or 0.25 mg/kg buccal; or oxymorphone hydrochloride, 0.1 mg/kg IV or 0.25 mg/kg buccal were administered. All cats received all treatments. Arterial blood was sampled immediately prior to drug administration and at various times up to 8 h thereafter. Bioavailability was calculated as the ratio of the area under the time-concentration curve following buccal administration to that following IV administration, each indexed to the administered dose. Mean ± SE (range) bioavailability was 36.6 ± 5.2 (12.7-49.5), 44.2 ± 7.9 (18.7-70.5), 22.4 ± 6.9 (6.4-43.4), and 18.8 ± 2.0 (12.9-23.5)% for buccal administration of morphine, methadone, hydromorphone, and oxymorphone, respectively. Bioavailability of methadone was significantly higher than that of oxymorphone. © 2013 John Wiley & Sons Ltd.

  3. Design and optimization of self-nanoemulsifying drug delivery systems for improved bioavailability of cyclovirobuxine D

    Directory of Open Access Journals (Sweden)

    Ke ZC

    2016-06-01

    Full Text Available Zhongcheng Ke,1–3 Xuefeng Hou,4 Xiao-bin Jia31Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 2Huangshan University, Huangshan, Anhui, 3Third Clinical Medical College, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 4Anhui University of Chinese Medicine, Hefei, Anhui, People’s Republic of ChinaBackground: The main purpose of this research was to design a self-nanoemulsifying drug delivery system (SNEDDS for improving the bioavailability of cyclovirobuxine D as a poorly water-soluble drug.Materials and methods: Solubility trials, emulsifying studies, and pseudo-ternary phase diagrams were used to screen the SNEDDS formulations. The optimized drug-loaded SNEDDS was prepared at a mass ratio of 3:24:38:38 for cyclovirobuxine D, oleic acid, Solutol SH15, and propylene glycol, respectively. The optimized formulation was characterized in terms of physicochemical and pharmacokinetic parameters compared with marketed cyclovirobuxine D tablets.Results: The optimized cyclovirobuxine-D-loaded SNEDDS was spontaneously dispersed to form a nanoemulsion with a globule size of 64.80±3.58 nm, which exhibited significant improvement of drug solubility, rapid absorption rate, and enhanced area under the curve, together with increased permeation and decreased efflux. Fortunately, there was a nonsignificant cytotoxic effect toward Caco-2 cells. The relative bioavailability of SNEDDS was 200.22% in comparison with market tablets, in rabbits.Conclusion: SNEDDS could be a potential candidate for an oral dosage form of cyclovirobuxine D with improved bioavailability.Keywords: self-nanoemulsifying drug delivery, bioavailability, cyclovirobuxine D

  4. Isotope-aided studies of the bioavailability of iron from Myanmar diets

    International Nuclear Information System (INIS)

    Khin Maung Naing; Myo Khin

    1992-01-01

    Iron deficiency is an important nutritional problem in Myanmar. The preliminary studies in this paper are to be used as a feasibility study for an iron fortification programme in Myanmar. This programme is now in the planning stages. This paper contains summaries of information gathered from a dietary survey, isotope-aided studies of the bioavailability of iron from the daily diet, and a work plan for fortifying table salt with iron. 6 refs, 6 tabs

  5. Sublingual fast dissolving niosomal films for enhanced bioavailability and prolonged effect of metoprolol tartrate

    OpenAIRE

    Allam, Ayat; Fetih, Gihan

    2016-01-01

    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...

  6. Improved Oral Bioavailability and Brain Transport of Saquinavir Upon Administration in Novel Nanoemulsion Formulations

    OpenAIRE

    Vyas, Tushar K.; Shahiwala, Aliasgar; Amiji, Mansoor M.

    2007-01-01

    The aim of this investigation was to develop novel oil-in-water (o/w) nanoemulsions containing saquinavir (SQV), an anti-HIV protease inhibitor, for enhanced oral bioavailability and brain disposition. SQV was dissolved in different types of edible oils rich in essential polyunsaturated fatty acids (PUFA) to constitute the internal oil phase of the nanoemulsions. The external phase consisted of surfactants Lipoid®-80 and deoxycholic acid dissolved in water. The nanoemulsions with an average o...

  7. Enhanced anticancer activity and oral bioavailability of ellagic acid through encapsulation in biodegradable polymeric nanoparticles.

    Science.gov (United States)

    Mady, Fatma M; Shaker, Mohamed A

    2017-01-01

    Despite the fact that various studies have investigated the clinical relevance of ellagic acid (EA) as a naturally existing bioactive substance in cancer therapy, little has been reported regarding the efficient strategy for improving its oral bioavailability. In this study, we report the formulation of EA-loaded nanoparticles (EA-NPs) to find a way to enhance its bioactivity as well as bioavailability after oral administration. Poly(ε-caprolactone) (PCL) was selected as the biodegradable polymer for the formulation of EA-NPs through the emulsion-diffusion-evaporation technique. The obtained NPs have been characterized by measuring particle size, zeta potential, Fourier transform infrared, differential scanning calorimetry, and X-ray diffraction. The entrapment efficiency and the release profile of EA was also determined. In vitro cellular uptake and cytotoxicity of the obtained NPs were evaluated using Caco-2 and HCT-116 cell lines, respectively. Moreover, in vivo study has been performed to measure the oral bioavailability of EA-NPs compared to free EA, using New Zealand white rabbits. NPs with distinct shape were obtained with high entrapment and loading efficiencies. Diffusion-driven release profile of EA from the prepared NPs was determined. EA-NP-treated HCT-116 cells showed relatively lower cell viability compared to free EA-treated cells. Fluorometric imaging revealed the cellular uptake and efficient localization of EA-NPs in the nuclear region of Caco-2 cells. In vivo testing revealed that the oral administration of EA-NPs produced a 3.6 times increase in the area under the curve compared to that of EA. From these results, it can be concluded that incorporation of EA into PCL as NPs enhances its oral bioavailability and activity.

  8. 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.

  9. Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics

    OpenAIRE

    Zenei Taira, Zenei; Ueda,Yukari

    2013-01-01

    Yukari Ueda, Zenei TairaFaculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, JapanAbstract: We studied the absolute bioavailability of calcium from calcium L-lactate in mice using pharmacokinetics, and reviewed the absolute bioavailability of calcium from three other calcium salts in mice previously studied: calcium chloride, calcium acetate, and calcium ascorbate. The results showed that calcium metabolism is linear between intravenous administration of 15 mg/kg and 30 ...

  10. Bioavailability of andrographolide and protection against carbon tetrachloride-induced oxidative damage in rats.

    Science.gov (United States)

    Chen, Haw-Wen; Huang, Chin-Shiu; Li, Chien-Chun; Lin, Ai-Hsuan; Huang, Yu-Ju; Wang, Tsu-Shing; Yao, Hsien-Tsung; Lii, Chong-Kuei

    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 1μM which peaked at 30min. The bioavailability of andrographolide was 1.19%. In a hepatoprotection study, rats were intragastrically dosed with 30 or 50mg/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 (pandrographolide 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 (CCl4) at day 6. Andrographolide pretreatment suppressed CCl4-induced plasma aminotransferase activity and hepatic lipid peroxidation (pandrographolide 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. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. A randomised cross-over pharmacokinetic bioavailability study of synthetic versus kiwifruit-derived vitamin C.

    Science.gov (United States)

    Carr, Anitra C; Bozonet, Stephanie M; Vissers, Margreet C M

    2013-11-11

    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 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.

  12. In vitro and in vivo evaluation of capsaicin-loaded microemulsion for enhanced oral bioavailability.

    Science.gov (United States)

    Zhu, Yuan; Zhang, Jiajia; Zheng, Qianfeng; Wang, Miaomiao; Deng, Wenwen; Li, Qiang; Firempong, Caleb Kesse; Wang, Shengli; Tong, Shanshan; Xu, Ximing; Yu, Jiangnan

    2015-10-01

    Capsaicin, as a food additive, has attracted worldwide concern owing to its pungency and multiple pharmacological effects. However, poor water solubility and low bioavailability have limited its application. This study aims to develop a capsaicin-loaded microemulsion to enhance the oral bioavailability of the anti-neuropathic-pain component, capsaicin, which is poorly water soluble. In this study, the microemulsion consisting of Cremophor EL, ethanol, medium-chain triglycerides (oil phase) and water (external phase) was prepared and characterized (particle size, morphology, stability and encapsulation efficiency). The gastric mucosa irritation test of formulated capsaicin was performed in rats to evaluate its oral feasibility, followed by the pharmacokinetic study in vivo. Under these conditions, the encapsulated capsaicin revealed a faster capsaicin release in vitro coupled with a greater absorption in vivo when compared to the free capsaicin. The oral bioavailability of the formulated capsaicin-loaded microemulsions was 2.64-fold faster than that of free capsaicin. No significant irritation was observed on the mucosa from the pathological section of capsaicin-loaded microemulsion treated stomach. These results indicate that the developed microemulsion represents a safe and orally effective carrier for poorly soluble substances. The formulation could be used for clinical trials and expand the application of capsaicin. © 2014 Society of Chemical Industry.

  13. Phenazopyridine-phthalimide nano-cocrystal: Release rate and oral bioavailability enhancement.

    Science.gov (United States)

    Huang, Yu; Li, Jin-Mei; Lai, Zhi-Hui; Wu, Jun; Lu, Tong-Bu; Chen, Jia-Mei

    2017-11-15

    Both cocrystal and nanocrystal technologies have been widely used in the pharmaceutical development for poorly soluble drugs. However, the synergistic effects due to the integration of these two technologies have not been well investigated. The aim of this study is to develop a nano-sized cocrystal of phenazopyridine (PAP) with phthalimide (PI) to enhance the release rate and oral bioavailability of PAP. A PAP-PI nano-cocrystal with particle diameter of 21.4±0.1nm was successfully prepared via a sonochemical approach and characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and dynamic light scattering (DLS) analysis. An in vitro release study revealed a significant release rate enhancement for PAP-PI nano-cocrystal as compared to PAP-PI cocrystal and PAP hydrochloride salt. Further, a comparative oral bioavailability study in rats indicated significant improvement in C max and oral bioavailability (AUC 0-∞ ) by 1.39- and 2.44-fold, respectively. This study demonstrated that this novel nano-cocrystal technology can be a new promising option to improve release rate and absorption of poorly soluble compounds in the pharmaceutical industry. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Migration and bioavailability of 137Cs in forest soil of southern Germany

    International Nuclear Information System (INIS)

    Konopleva, I.; Klemt, E.; Konoplev, A.; Zibold, G.

    2009-01-01

    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. Methods to assess bioavailability of hydrophobic organic contaminants: Principles, operations, and limitations

    International Nuclear Information System (INIS)

    Cui Xinyi; Mayer, Philipp; Gan, Jay

    2013-01-01

    Many important environmental contaminants are hydrophobic organic contaminants (HOCs), which include PCBs, PAHs, PBDEs, DDT and other chlorinated insecticides, among others. Owing to their strong hydrophobicity, HOCs have their final destination in soil or sediment, where their ecotoxicological effects are closely regulated by sorption and thus bioavailability. The last two decades have seen a dramatic increase in research efforts in developing and applying partitioning based methods and biomimetic extractions for measuring HOC bioavailability. However, the many variations of both analytical methods and associated measurement endpoints are often a source of confusion for users. In this review, we distinguish the most commonly used analytical approaches based on their measurement objectives, and illustrate their practical operational steps, strengths and limitations using simple flowcharts. This review may serve as guidance for new users on the selection and use of established methods, and a reference for experienced investigators to identify potential topics for further research. - This review summarizes the principles and operations of bioavailability prediction methods, discusses their strengths and limitations, and highlights issues for future research.

  16. Bioavailability of Trace Elements in Beans and Zinc-Biofortified Wheat in Pigs

    DEFF Research Database (Denmark)

    Carlson, Dorthe; Nørgaard, Jan Værum; Torun, B

    2012-01-01

    The objectives of this experiment were to study bioavailability of trace elements in beans and wheat containing different levels of zinc and to study how the water solubility of trace elements was related to the bioavailability in pigs. Three wheat and two bean types were used: wheat of Danish...... origin as a control (CtrlW), two Turkish wheat types low (LZnW) and high (HZnW) in zinc, a common bean (Com), and a faba bean (Faba). Two diets were composed by combining 81 % CtrlW and 19 % Com or Faba beans. Solubility was measured as the trace element concentration in the supernatant of feedstuffs......, and diets incubated in distilled water at pH 4 and 38°C for 3 h. The bioavailability of zinc and copper of the three wheat types and the two bean-containing diets were evaluated in the pigs by collection of urine and feces for 7 days. The solubility of zinc was 34–63 %, copper 18–42 %, and iron 3...

  17. Iron Bioavailability Studies of the First Generation of Iron-Biofortified Beans Released in Rwanda.

    Science.gov (United States)

    Glahn, Raymond; Tako, Elad; Hart, Jonathan; Haas, Jere; Lung'aho, Mercy; Beebe, Steve

    2017-07-21

    This paper represents a series of in vitro iron (Fe) bioavailability experiments, Fe content analysis and polyphenolic profile of the first generation of Fe biofortified beans ( Phaseolus vulgaris ) selected for human trials in Rwanda and released to farmers of that region. The objective of the present study was to demonstrate how the Caco-2 cell bioassay for Fe bioavailability can be utilized to assess the nutritional quality of Fe in such varieties and how they may interact with diets and meal plans of experimental studies. Furthermore, experiments were also conducted to directly compare this in vitro approach with specific human absorption studies of these Fe biofortified beans. The results show that other foods consumed with beans, such as rice, can negatively affect Fe bioavailability whereas potato may enhance the Fe absorption when consumed with beans. The results also suggest that the extrinsic labelling approach to measuring human Fe absorption can be flawed and thus provide misleading information. Overall, the results provide evidence that the Caco-2 cell bioassay represents an effective approach to evaluate the nutritional quality of Fe-biofortified beans, both separate from and within a targeted diet or meal plan.

  18. Optimization of Fe2+ supplement in anaerobic digestion accounting for the Fe-bioavailability.

    Science.gov (United States)

    Cai, Yafan; Zhao, Xiaoling; Zhao, Yubin; Wang, Hongliang; Yuan, Xufeng; Zhu, Wanbin; Cui, Zongjun; Wang, Xiaofen

    2018-02-01

    Fe is widely used as an additive in anaerobic digestion, but its bioavailability and the mechanism by which it enhances digestion are unclear. In this study, sequential extraction was used to measure Fe bioavailability, while biochemical parameters, kinetics model and Q-PCR (fluorescence quantitative PCR) were used to explore its mechanism of stimulation. The results showed that sequential extraction is a suitable method to assess the anaerobic system bioavailability of Fe, which is low and fluctuates to a limited extent (1.7 to -3.1wt%), indicating that it would be easy for Fe levels to be insufficient. Methane yield increased when the added Fe 2+ was 10-500mg/L. Appropriate amounts of Fe 2+ accelerated the decomposition of rice straw and facilitated methanogen metabolism, thereby improving reactor performance. The modified Gompertz model better fitted the results than the first-order kinetic model. Feasibility analysis showed that addition of Fe 2+ at ≤50mg/L was suitable. Copyright © 2017. Published by Elsevier Ltd.

  19. 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.

  20. Bioavailability of residual polycyclic aromatic hydrocarbons following enhanced natural attenuation of creosote-contaminated soil

    International Nuclear Information System (INIS)

    Juhasz, Albert L.; Smith, Euan; Waller, Natasha; Stewart, Richard; Weber, John

    2010-01-01

    The impact of residual PAHs (2250 ± 71 μg total PAHs g -1 ) following enhanced natural attenuation (ENA) of creosote-contaminated soil (7767 ± 1286 μg total PAHs g -1 ) was assessed using a variety of ecological assays. Microtox TM results for aqueous soil extracts indicated that there was no significant difference in EC 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.