WorldWideScience

Sample records for bioavailability

  1. Human Folate Bioavailability

    Directory of Open Access Journals (Sweden)

    Cornelia M. Witthoft

    2011-04-01

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

  2. Bioavailability of Tea Polyphenols

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

  3. Bioavailability and generic prescribing.

    Science.gov (United States)

    Mindel, J S

    1976-01-01

    Although oral drug bioinequivalence has been attributed to a number of causes (excipients, dosage form, variation in dissolution time, and aging) less is known about bioavailability problems of topical medications in ophthalmology. Factors that can alter drug absorption from solutions (pH, partition coefficient, container impurities, contact time, etc.) are noted, and cases in which bioavailability problems should be considered as causes of therapeutic failure are discussed. Various attitudes representing pharmaceutical companies, the federal government, pharmacists, consumers and physicians toward the related problems of bioinequivalence and generic prescribing are examined. Techniques for in vivo and in vitro drug testing and for establishing uniform conditions of drug manufacture and storage can contribute to identification and minimization of bioavailability problems. A rational program based on a combination of such techniques could, ultimately, lead to establishment of the terms "generic equivalency" and "therapeutic equivalency" as synonymous. PMID:13505

  4. SLUDGE ORGANICS BIOAVAILABILITY

    Science.gov (United States)

    Concern over the bioavailability of toxic organics that can occur in municipal sludges threatens routine land application of sludge. vailable data, however, show that concentrations of priority organics in normal sludges are low. ludges applied at agronomic rates yield chemical c...

  5. Micronutrient bioavailability research priorities.

    Science.gov (United States)

    Casgrain, Amélie; Collings, Rachel; Harvey, Linda J; Boza, Julio J; Fairweather-Tait, Susan J

    2010-05-01

    A micronutrient bioavailability workshop, which involved international experts and members of the scientific community and the food industry, with interactive breakout sessions based on synectics principles, was organized by the International Life Sciences Institute Europe Addition of Nutrients to Food Task Force and the European Commission Network of Excellence European Micronutrient Recommendations Aligned. After presentations by experts, a series of "challenge statements" was discussed. The aim was to address topical issues, in particular those that linked bioavailability with the derivation of micronutrient requirements and dietary recommendations, to identify gaps in knowledge and to consider research priorities. Several generic research priorities were identified, including improving the quality of dietary surveys/food composition tables, the need for more metabolic studies that use stable isotopes and high-quality longer-term interventions, and the development of multifactorial mathematical models. Among the common recurrent factors identified as important were polymorphisms/genotype, consideration of the whole diet, chemical form of the micronutrient, and the determination of physiologic requirements. The involvement of all participants in the structured discussions ensured a broad overview of current knowledge, state-of-the-art research, and consideration of priorities for future research. PMID:20200267

  6. Zinc bioavailability in the chick

    International Nuclear Information System (INIS)

    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 65Zn, 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%

  7. Bioavailability & Bioequivalence Studies ? Pharmaceutical Importance

    Directory of Open Access Journals (Sweden)

    Pratibha Muntha

    2015-04-01

    Full Text Available Pharmacokinetics has now emerged as an important part of drug development especially in the development of new drugs. The combined studies of Pharmacodynamics and pharmacokinetics present a thorough understanding on how the drug affects the body and how the body affects the drug.Bioavailability is the study of the rate and extent to which the active ingredient is absorbed from a dosage form and it is available at the required action site. Bioequivalence is that there should not be any significant difference in bioavailability between two products.Bioavailability (BA and bioequivalence (BE studies play a key role during the phase of drug development for both innovator drugs and generic drugs and thus have gained great attention over the past few decades. BE is used to introduce generic drugs of innovator drugs at a lower cost. So a thorough understanding of these BA/BE studies is required

  8. Dietary factors that affect carotenoid bioavailability

    NARCIS (Netherlands)

    Hof, van het K.

    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 bioavailability.In a

  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. Bioavailability of the polyphenols: status and controversies.

    Science.gov (United States)

    D'Archivio, Massimo; Filesi, Carmelina; Varì, Rosaria; Scazzocchio, Beatrice; Masella, Roberta

    2010-01-01

    The current interest in polyphenols has been driven primarily by epidemiological studies. However, to establish conclusive evidence for the effectiveness of dietary polyphenols in disease prevention, it is useful to better define the bioavailability of the polyphenols, so that their biological activity can be evaluated. The bioavailability appears to differ greatly among the various phenolic compounds, and the most abundant ones in our diet are not necessarily those that have the best bioavailability profile. In the present review, we focus on the factors influencing the bioavailability of the polyphenols. Moreover, a critical overview on the difficulties and the controversies of the studies on the bioavailability is discussed. PMID:20480022

  12. Bioavailability of the Polyphenols: Status and Controversies

    Directory of Open Access Journals (Sweden)

    Massimo D’Archivio

    2010-03-01

    Full Text Available The current interest in polyphenols has been driven primarily by epidemiological studies. However, to establish conclusive evidence for the effectiveness of dietary polyphenols in disease prevention, it is useful to better define the bioavailability of the polyphenols, so that their biological activity can be evaluated. The bioavailability appears to differ greatly among the various phenolic compounds, and the most abundant ones in our diet are not necessarily those that have the best bioavailability profile. In the present review, we focus on the factors influencing the bioavailability of the polyphenols. Moreover, a critical overview on the difficulties and the controversies of the studies on the bioavailability is discussed.

  13. Bioavailability & Bioequivalence Studies ? Pharmaceutical Importance

    OpenAIRE

    Pratibha Muntha

    2015-01-01

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

  14. Oral iron and the bioavailability of zinc.

    OpenAIRE

    Meadows, N J; Grainger, S L; Ruse, W; Keeling, P W; Thompson, R. P.

    1983-01-01

    The oral bioavailability of zinc was studied in nonpregnant adults before and 24 hours after two weeks of oral supplementation with iron and folic acid. Bioavailability was greatly reduced, and the shape of the plasma curves suggested that this was due to impairment of the intestinal absorption of zinc. The findings suggest that the reduced bioavailability of zinc occurs because of interelement competition in the bowel wall. This might induce zinc depletion.

  15. Effect of Bioenhancers on Amoxicillin bioavailability

    OpenAIRE

    Barve, Kalyani; Ruparel, Kushal

    2015-01-01

    Amoxicillin, which inspite of being effective is losing its importance due to less bioavailability. Bioavailability could be enhanced by combining the antibiotics with bioenhancers like Piperine and Ginger resin. The present abstract deals with the use of piperine and ginger resin in increasing the bioavailability of amoxicillin using the insitu SPIP method. Piperine, isolated was found to be 99 % pure and ginger resin contained 4.36 % w/w of gingerol. The absorption of amoxicillin increased ...

  16. Antimony bioavailability in mine soils

    International Nuclear Information System (INIS)

    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

  17. Bioavailability of xenobiotics in the soil environment.

    Science.gov (United States)

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

    2010-01-01

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

  18. Bioavailability: implications for science/cleanup policy; FINAL

    International Nuclear Information System (INIS)

    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

  19. Bioavailability of rectally administered carbamazepine mixture.

    OpenAIRE

    Neuvonen, P J; Tokola, O.

    1987-01-01

    The relative bioavailability of carbamazepine mixture was studied after oral and rectal administration to healthy subjects. The absorption was significantly slower after the rectal than after the oral route but the total bioavailability was similar provided the mixture was not defaecated within 2 h of administration. We conclude that carbamazepine can be administered rectally, e.g. to postoperative patients in doses corresponding with oral doses.

  20. Iron bioavailability from commercially available iron supplements

    OpenAIRE

    Christides, Tatiana; Wray, David; McBride, Richard; Fairweather, Rose; Sharp, Paul

    2015-01-01

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

  1. Bioavailability of the Polyphenols: Status and Controversies

    OpenAIRE

    Massimo D’Archivio; Carmelina Filesi; Rosaria Varì; Beatrice Scazzocchio; Roberta Masella

    2010-01-01

    The current interest in polyphenols has been driven primarily by epidemiological studies. However, to establish conclusive evidence for the effectiveness of dietary polyphenols in disease prevention, it is useful to better define the bioavailability of the polyphenols, so that their biological activity can be evaluated. The bioavailability appears to differ greatly among the various phenolic compounds, and the most abundant ones in our diet are not necessarily those that have the best bioavai...

  2. Bioavailability and Bioequivalence in Drug Development

    OpenAIRE

    Chow, Shein-Chung

    2014-01-01

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

  3. Heavy metal bioavailability and bioaccessibility in soil

    OpenAIRE

    Dean, John

    2009-01-01

    This chapter considers the use of a variety of approaches to assess either the bioavailability or the bioaccessibility of metals in soil. The bioavailability of metals from soils is considered with respect to a series of single-extraction methods, including the use of ethylenediaminetetraacetic acid (EDTA), acetic acid, diethylenetriaminepentaacetic acid (DTPA), ammonium nitrate, calcium chloride and sodium nitrate. Then, a procedure for the recovery of metals using a three-stage sequential e...

  4. Improved bioavailability through floating microspheres of lovastatin

    OpenAIRE

    Kumar, S.; K Nagpal; Singh SK; DN Mishra

    2011-01-01

    "n Background and the purpose of the study: Lovastatin is an antihyperlipidemic agent which has low bioavailability due to the extensive first pass metabolism. It was sought to increase gastric retention of lovastatin by development of a sustained release gastroretentive drug delivery system leading to reduced fluctuation in the plasma concentration and improved bioavailability. "nMethods: Floating microspheres were prepared by emulsion solvent diffusion technique, using va...

  5. Bioavailability enhancers of herbal origin: an overview.

    Science.gov (United States)

    Kesarwani, Kritika; Gupta, Rajiv; Mukerjee, Alok

    2013-04-01

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

  6. Bioavailability of nanoparticulate hematite to Arabidopsis thaliana

    International Nuclear Information System (INIS)

    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

  7. Chemical speciation and bioavailability in radioecological research

    International Nuclear Information System (INIS)

    The science of radioecology in the framework of the CEC Radiation Protection Research Action is considered to serve to unravel the specific interaction between the ecosphere and the radioactivity as a chemical event, in order to deliver the reliable data for the dose calculation, to reveal the most sensitive eco-compartments (trophic level) in a foodchain, and to develop the skills needed in the technique of remedial actions, based onsound scientific principles. In this context speciation and bio-availability plays a more predominant role than originally envisaged. These parameters are however often not very well quantified or considered in the genuine context (ecosystem) were the changes in speciation or bio-availability occur. This paper is an attempt to elucidate some of the basic principles behind speciation and bio-availability. (orig.)

  8. Bioavailability of Plant-Derived Antioxidants

    Directory of Open Access Journals (Sweden)

    Ehab A. Abourashed

    2013-11-01

    Full Text Available Natural products with antioxidant properties have been extensively utilized in the pharmaceutical and food industry and have also been very popular as health-promoting herbal products. This review provides a summary of the literature published around the first decade of the 21st century regarding the oral bioavailability of carotenoids, polyphenols and sulfur compounds as the three major classes of plant-derived antioxidants. The reviewed original research includes more than 40 compounds belonging to the above mentioned classes of natural antioxidants. In addition, related reviews published during the same period have been cited. A brief introduction to general bioavailability-related definitions, procedures and considerations is also included.

  9. Bioavailability of cadmium from linseed and cocoa

    OpenAIRE

    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 ...

  10. 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...

  11. Animal versus human oral drug bioavailability: Do they correlate?

    OpenAIRE

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

    2014-01-01

    Oral bioavailability is a key consideration in development of drug products, and the use of preclinical species in predicting bioavailability in human has long been debated. In order to clarify whether any correlation between human and animal bioavailability exist, an extensive analysis of the published literature data was conducted. Due to the complex nature of bioavailability calculations inclusion criteria were applied to ensure integrity of the data. A database of 184 compounds was assemb...

  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 ...... crushed linseed nor the intake of cocoa and chocolate....

  13. Contact Sensitivity and Bioavailability of Chlorocresol

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Larsen, Elfinn; Carlsen, Lars; Andersen, K. E.

    1985-01-01

    Chlorocresol sensitization from 5 topical preparations was determined in guinea pigs using the cumulative contact enhancement test. Chlorocresol 5% in olive oil/acetone (4/1), and 5% in aqueous suspension stabilized with carbomer 941 were more sensitizing (55% and 60% of the animals positive, res....... No simple relationship between the sensitization rates and the calculated bioavailability was observed with the preparations tested....

  14. INTERSPECIFIC HYBRIDIZATION FOR INCREASED BIOAVAILABILITY OF ANTIOXIDANTS

    Science.gov (United States)

    Many flavonoids, including anthocyanins and flavonols, exist in plants as conjugates of sugars. Evidence suggests that the bioavailability of flavonoids in mammalian diets is a function of the sugar moiety, and that glucosides may be the preferred conjugates. Fruit of the American cranberry (Vaccini...

  15. Mineralogy affects geoavailability, bioaccessibility and bioavailability of zinc

    International Nuclear Information System (INIS)

    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 (65Zn. 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

  16. Oral bioavailability of curcumin: problems and advancements.

    Science.gov (United States)

    Liu, Weidong; Zhai, Yingjie; Heng, Xueyuan; Che, Feng Yuan; Chen, Wenjun; Sun, Dezhong; Zhai, Guangxi

    2016-09-01

    Curcumin is a natural compound of Curcuma longa L. and has shown many pharmacological activities such as anti-inflammatory, anti-oxidant in both preclinical and clinical studies. Moreover, curcumin has hepatoprotective, neuroprotective activities and protects against myocardial infarction. Particularly, curcumin has also demonstrated favorite anticancer efficacy. But limiting factors such as its extremely low oral bioavailability hampers its application as therapeutic agent. Therefore, many technologies have been developed and applied to overcome this limitation. This review described the main physicochemical properties of curcumin and summarized the recent studies in the design and development of oral delivery systems for curcumin to enhance the solubility and oral bioavailability, including liposomes, nanoparticles and polymeric micelles, phospholipid complexes, and microemulsions. PMID:26942997

  17. Mobility and Bioavailability of Radionuclides in Soils

    International Nuclear Information System (INIS)

    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

  18. Bioavailability enhancement studies of amoxicillin with Nigella

    OpenAIRE

    Ali, Babar; Amin, Saima; Ahmad, Javed; Ali, Abuzer; Ali, Mohd; Showkat R Mir

    2012-01-01

    Background & objectives: Nigella sativa Linn. is extensively used in the Indian diasporas as spice, which may interact with co-administered drugs and affect their intestinal availability. The purpose of this study was to investigate the effect of Nigella on bioavailability of amoxicillin in animal model. Methods: Everted rat intestinal sacs were used for in vitro experiment to study the transfer of amoxicillin across the gut. Amoxicillin (6 mg/ml) was co-infused with 3 and 6 mg of methanol an...

  19. Bioavailability enhancers of herbal origin: An overview

    OpenAIRE

    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...

  20. Bioavailability of Plant-Derived Antioxidants

    OpenAIRE

    Abourashed, Ehab A.

    2013-01-01

    Natural products with antioxidant properties have been extensively utilized in the pharmaceutical and food industry and have also been very popular as health-promoting herbal products. This review provides a summary of the literature published around the first decade of the 21st century regarding the oral bioavailability of carotenoids, polyphenols and sulfur compounds as the three major classes of plant-derived antioxidants. The reviewed original research includes more than 40 compounds belo...

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

    Science.gov (United States)

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

    2016-01-01

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

  2. 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.

  3. Bioavailability and biodistribution of nanodelivered lutein.

    Science.gov (United States)

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

    2016-02-01

    The aim of the study was to evaluate the ability of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NP) to enhance lutein bioavailability. The bioavailability of free lutein and PLGA-NP lutein in rats was assessed by determining plasma pharmacokinetics and deposition in selected tissues. Lutein uptake and secretion was also assessed in Caco-2 cells. Compared to free lutein, PLGA-NP increased the maximal plasma concentration (Cmax) and area under the time-concentration curve in rats by 54.5- and 77.6-fold, respectively, while promoting tissue accumulation in the mesenteric fat and spleen. In comparison with micellized lutein, PLGA-NP lutein improved the Cmax in rat plasma by 15.6-fold and in selected tissues by ⩾ 3.8-fold. In contrast, PLGA-NP lutein had a lower uptake and secretion of lutein in Caco-2 cells by 10.0- and 50.5-fold, respectively, compared to micellized lutein. In conclusion, delivery of lutein with polymeric NP may be an approach to improve the bioavailability of lutein in vivo. PMID:26304429

  4. Bioavailability of nanoparticulate hematite to Arabidopsis thaliana.

    Science.gov (United States)

    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

    2013-03-01

    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. PMID:23262070

  5. Relative bioavailability of three cefixime formulations.

    Science.gov (United States)

    Kees, F; Naber, K G; Sigl, G; Ungethüm, W; Grobecker, H

    1990-03-01

    Three galenic formulations of cefixime (tablet, syrup and dry suspension) containing 200 mg each were compared with respect to their relative bioavailability in twelve healthy volunteers. All three formulations showed reliable absorption. Mean peak plasma concentrations were reached after 3.3-3.5 h, mean terminal half lives were 2.9-3.1 h. 18-24% of the dose administered were recovered unchanged in the urine. Best bioavailability was obtained with the dry suspension (AUC0-infinity = 25.8 +/- 7.0 micrograms/ml h; Cmax = 3.4 +/- 0.9 microgram/ml), followed by the tablet (AUC0-infinity = 20.9 +/- 8.1 micrograms/ml h; Cmax = 3.0 +/- 1.0 micrograms/ml) and the syrup which is based on triglycerides (AUC0-infinity = 17.8 +/- 5.9 micrograms/ml h; Cmax = 2.4 +/- 0.7 micrograms/ml). The statistical analysis resulted in bioinequivalence between dry suspension and syrup. It is concluded that best bioavailability of cefixime after oral administration is guaranteed when taken in an "aqueous medium" either as dry suspension or as tablet with "plenty of liquid". PMID:2346538

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

    Science.gov (United States)

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

    2016-01-01

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

  7. Rapid screening assay for calcium bioavailability studies

    International Nuclear Information System (INIS)

    Calcium bioavailability has been studied by numerous techniques. The authors report here the use of the gamma emitting isotope of calcium (47Ca) 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 CaCO3. 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 47Ca. 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

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

    OpenAIRE

    Hambidge, K. Michael

    2010-01-01

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

  9. Mineralogy affects geoavailability, bioaccessibility and bioavailability of zinc

    OpenAIRE

    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 ( hydrozincite > hemimorphite > zincite ≈ smithsonite ≫ sphalerite. We found significant correlations among geoavailability, bioaccessibility and bioavailability. In particular, Zn bioavailability post-gava...

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

    Science.gov (United States)

    Platel, Kalpana; Srinivasan, Krishnapura

    2016-07-26

    Deficiencies of iron, zinc, iodine and vitamin A are widespread in the developing countries, poor bioavailability of these micronutrients from plant-based foods being the major reason for their wide prevalence. Diets predominantly vegetarian are composed of components that enhance as well as inhibit mineral bioavailability, the latter being predominant. However, prudent cooking practices and use of ideal combinations of food components can significantly improve micronutrient bioavailability. Household processing such as heat treatment, sprouting, fermentation and malting have been evidenced to enhance the bioavailability of iron and β-carotene from plant foods. Food acidulants amchur and lime are also shown to enhance the bioavailability of not only iron and zinc, but also of β-carotene. Recently indentified newer enhancers of micronutrient bioaccessibility include sulphur compound-rich Allium spices-onion and garlic, which also possess antioxidant properties, β-carotene-rich vegetables-carrot and amaranth, and pungent spices-pepper (both red and black) as well as ginger. Information on the beneficial effect of these dietary compounds on micronutrient bioaccessibility is novel. These food components evidenced to improve the bioavailability of micronutrients are common ingredients of Indian culinary, and probably of other tropical countries. Fruits such as mango and papaya, when consumed in combination with milk, provide significantly higher amounts of bioavailable β-carotene. Awareness of the beneficial influence of these common dietary ingredients on the bioavailability of micronutrients would help in devising dietary strategies to improve the bioavailability of these vital nutrients. PMID:25748063

  11. A reexamination of krill oil bioavailability studies.

    Science.gov (United States)

    Salem, Norman; Kuratko, Connye N

    2014-01-01

    It has proven difficult to compare the bioavailability of krill oil (KO) vs. fish oil (FO) due to several of the characteristics of KO. These include the lower concentration of the active ingredients, eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n3), in KO as well as differences in their ratio relative to FO as well as the red color due to astaxanthin. In addition, the lipid classes in which EPA and DHA are found are quite different with KO containing phospholipid, di- and tri-glycerides as well as non-esterified fatty acid forms and with FO being primarily triglycerides. No human study has yet been performed that matches the dose of EPA and DHA in a randomized, controlled trial with measures of bloodstream EPA and DHA content. However, several claims have been made suggesting greater bioavailability of KO vs. FO. These have largely been based on a statistical argument where a somewhat lower dose of KO has been used to result in a similar bloodstream level of EPA and/or DHA or their total. However, the magnitude of the dosage differential is shown to be too small to be expected to result in differing blood levels of the long chain n-3 PUFAs. Some studies which have claimed to provide equal doses of KO and FO have actually used differing amounts of the two major n-3 fatty acid constituents. It is concluded that there is at present no evidence for greater bioavailability of KO vs. FO and that more carefully controlled human trials must be performed to establish their relative efficacies after chronic administration. PMID:25156381

  12. A reexamination of krill oil bioavailability studies

    OpenAIRE

    Salem, Norman; Kuratko, Connye N.

    2014-01-01

    It has proven difficult to compare the bioavailability of krill oil (KO) vs. fish oil (FO) due to several of the characteristics of KO. These include the lower concentration of the active ingredients, eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n3), in KO as well as differences in their ratio relative to FO as well as the red color due to astaxanthin. In addition, the lipid classes in which EPA and DHA are found are quite different with KO containing phospholipid, ...

  13. Animal bioavailability of defined xenobiotic lignin metabolites

    International Nuclear Information System (INIS)

    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-14C-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-14C]chloroaniline/lignin metabolites

  14. Bioavailability of cadmium from linseed and cocoa

    DEFF Research Database (Denmark)

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

    2014-01-01

    the food authorities in order to give correct advises to the population. The aim of this study was to investigate the bioavailability of cadmium from whole linseed, crushed linseed, cocoa and cadmium chloride in rats. An experiment where 40 rats were divided into 4 groups and a control group and dosed...... with whole linseed, crushed linseed, cocoa and CdCl2 for 3 weeks was performed. Linseed or cocoa made up 10% of the feed (by weight) and was added as a replacement for carbohydrate source. The rats were dosed for 3 weeks and the cadmium content in the rats' kidneys was measured by ICPMS as a biomarker...... which could 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...

  15. Bioavailability of platinum emitted from automobile exhaust.

    Science.gov (United States)

    Artelt, S; Kock, H; Nachtigall, D; Heinrich, U

    1998-08-01

    A model substance was used which is similar in respect to platinum content of exhaust particles emitted from a three-way-catalytic converter equipped engine. The bioavailability of platinum from such exhaust particles and the kind of platinum species formed in vivo were assessed. An in vitro solubility test showed a solubility of approximately 10 percent of platinum content of the model substance in physiological sodium chloride solution. Two short-term animal studies (8 days) were performed. In all examined rat tissues and body fluids platinum could be detected. In addition, the contribution of the overall bioavailability caused by swallowing a certain amount of the intratracheally applied platinum was evaluated by oral application. It was very low. An analytical method was developed to determine platinum species. Synthetic samples (matrix with a platinum standard solution) were analysed. In rat bronchoalveolar lavage spiked with a platinum standard solution only low molecular complexed platinum was found whereas in rat blood plasma all platinum was bound to proteins. In ongoing studies, the model substance is being tested in a three month rat inhalation study. PMID:9820662

  16. Polymeric microcontainers improve oral bioavailability of furosemide.

    Science.gov (United States)

    Nielsen, Line Hagner; Melero, Ana; Keller, Stephan Sylvest; Jacobsen, Jette; Garrigues, Teresa; Rades, Thomas; Müllertz, Anette; Boisen, Anja

    2016-05-17

    Microcontainers with an inner diameter of 223μm are fabricated using the polymer SU-8, and evaluated in vitro, in situ and in vivo for their application as an advanced oral drug delivery system for the poorly water soluble drug furosemide. An amorphous sodium salt of furosemide (ASSF) is filled into the microcontainers followed by applying a lid using Eudragit L100. It is possible to control the drug release in vitro, and in vitro absorption studies show that the microcontainers are not a hindrance for absorption of ASSF. In situ perfusion studies in rats are performed with ASSF-filled microcontainers coated with Eudragit and compared to a furosemide solution. The absorption rate constant of ASSF confined in microcontainers is found to be significantly different from the solution, and by light microscopy, it is observed that the microcontainers are engulfed by the intestinal mucus. An oral bioavailability study in rats is performed with ASSF confined in microcontainers coated with Eudragit and a control group with ASSF in Eudragit-coated capsules. A relative bioavailability of 220% for the ASSF in microcontainers compared to ASSF in capsules is found. These studies indicate that the microcontainers could serve as a promising oral drug delivery system. PMID:27033999

  17. Improved bioavailability through floating microspheres of lovastatin

    Directory of Open Access Journals (Sweden)

    S Kumar

    2011-03-01

    Full Text Available "n Background and the purpose of the study: Lovastatin is an antihyperlipidemic agent which has low bioavailability due to the extensive first pass metabolism. It was sought to increase gastric retention of lovastatin by development of a sustained release gastroretentive drug delivery system leading to reduced fluctuation in the plasma concentration and improved bioavailability. "nMethods: Floating microspheres were prepared by emulsion solvent diffusion technique, using various polymers and their blends. The in vitro performance was evaluated for drug-polymer compatibility, percent yield, particle size, drug entrapment efficiency, in vitro onset and duration of floatation, in vitro drug release as well as in vivo determination of serum cholesterol level. "nResults: The mean particle size of microspheres was observed to be between 6.9 to 9.5 μm and the maximum particle size was around 50 μm. In vivo studies of the selected batches indicated lower level of serum cholesterol compared to the marketed tablet at the same dose but was not significant. Major conclusion: The data obtained in this study suggested that a microparticulate floating dosage form of lovastatin can be successfully designed to yield controlled delivery with improved therapeutic efficacy.

  18. 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...

  19. Dietary factors that affect the bioavailability of carotenoids

    NARCIS (Netherlands)

    Hof, van het K.H.; West, C.E.; Weststrate, J.A.; Hautvast, J.G.A.J.

    2000-01-01

    Carotenoids are thought to contribute to the beneficial effects of increased vegetable consumption. Various dietary factors have an effect on the bioavailability of carotenoids. The type of food matrix in which carotenoids are located is a major factor. The bioavailability of ß-carotene from vegetab

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

    DEFF Research Database (Denmark)

    Mu, Huiling; Müllertz, Anette

    2015-01-01

    Marine lipids are enriched with omega-3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Omega-3 fatty acids are important membrane lipids and have many recognized health benefits, the bioavailability of these fatty acids can therefore be important for achieving...... bioavailability 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....... 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...

  1. Hemicellulose does not affect iron bioavailability in chicks.

    Science.gov (United States)

    Fly, A D; Czarnecki-Maulden, G L; Fahey, G C; Titgemeyer, E C

    1996-01-01

    Two iron repletion experiments using hemoglobin as a response criterion were conducted to assess effects of hemicelluloses on iron bioavailability to chicks. In Experiment 1, iron bioavailability from intact fiber sources was determined by adding tomato pomace (14.6% hemicelluloses), soybean hulls (20.6% hemicelluloses), beet pulp (21.5% hemicelluloses), orchard grass (24.1% hemicelluloses) and corn fiber (55.2% hemicelluloses) to a casein dextrose basal diet providing 0.4-4.1% hemicelluloses to the diet. Test foods were analyzed for iron, total dietary fiber, neutral detergent residue, neutral detergent fiber, acid detergent fiber, acid detergent lignin, pectins and uronic acids. Hemicelluloses were determined by the difference of neutral detergent residue minus acid detergent fiber. Iron bioavailability was determined by the standard curve method to be (percent relative to ferrous sulfate using hemoglobin as the response criterion) as follows: tomato pomace, 82.0; soybean hulls, 94.0; beet pulp, 26.5; orchard grass, 68.9; corn fiber, 69.4. Iron bioavailability was not related to hemicellulose content of test foods or diets. In Experiment 2, the effect of psyllium husk (a fiber source that contains predominantly hemicelluloses) on iron bioavailability from ferrous sulfate was assessed. Bioavailability was determined by the slope ratio method where treatments consisted of graded levels of ferrous sulfate in the presence and absence of 5% dietary psyllium. Although iron intrinsic to psyllium was unavailable, bioavailability of ferrous sulfate iron was not affected (P > 0.05) by the presence of psyllium. Thus, there was no clear effect of hemicelluloses on iron bioavailability. However, some feeds that contained high levels of hemicelluloses had low intrinsic iron bioavailabilities, suggesting that other dietary factors are primarily responsible for determining iron bioavailability from these feed components. PMID:8558316

  2. 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

  3. 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.

  4. Bioavailability of magnetic nanoparticles to the brain

    International Nuclear Information System (INIS)

    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.

  5. Gender differences on bioavailability of ofloxacin

    International Nuclear Information System (INIS)

    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)

  6. Bioavailability of vitamin A sources for cattle.

    Science.gov (United States)

    Alosilla, C E; McDowell, L R; Wilkinson, N S; Staples, C R; Thatcher, W W; Martin, F G; Blair, M

    2007-05-01

    An experiment was conducted to evaluate the bioavailability of 5 sources of vitamin A. It was hypothesized that some vitamin A products have protective coatings that are more resistant than others to rumen destruction and that such protection would result in greater tissue concentrations of vitamin A. Fifty-three yearling Angus x Brahman cattle, consisting of 39 steers and 14 heifers, were stratified by BW and sex and randomly assigned to 6 high-concentrate diet groups receiving no vitamin A supplementation (control) or vitamin A supplemented from the following sources: Microvit A (Adisseo, Acworth, GA), Rovamix A (DSM, Parsippany, NJ), Sunvit A, Lutavit A, and Microvit A DLC (Adisseo). The vitamin A treatment groups were fed daily 80,000 IU of retinol/animal in a low-retinol concentrate diet (78.5% oats, 10% cottonseed hulls, 8% molasses, and 2% cottonseed meal; DM basis) and a free-choice, poor quality (low carotene) hay for 84 d. Every 28 d, BW was determined and liver biopsies and plasma were collected and analyzed for retinol concentrations. All retinol treatments showed significant increases in liver retinol concentrations compared with control animals (P < 0.0001), which steadily decreased over time. At all collection times, Microvit A led to numerically, but not significantly, greater concentrations of retinol in liver than did all other treatments. However, at the end of the experiment, there was no significant difference in liver retinol concentration among Microvit A, Rovamix A, Lutavit A, and Microvit A DLC diets. When liver retinol concentrations at all collection times were considered, Microvit A and Rovamix A appeared to provide the most bioavailable vitamin A. PMID:17178810

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

    International Nuclear Information System (INIS)

    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 64Cu 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 64Cu dose) in d 20 rats, 9 h postintubation, was low compared to the bioavailability from cow milk or human milk alone. 65Zn 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 54Mn) was high from all milks and commercial formulas tested

  8. 21 CFR 320.30 - Inquiries regarding bioavailability and bioequivalence requirements and review of protocols by...

    Science.gov (United States)

    2010-04-01

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

  9. Bioavailability of Bacampicillin and Talampicillin, Two Oral Prodrugs of Ampicillin

    OpenAIRE

    Sjövall, Jan; Magni, Lennart; Vinnars, Erik

    1981-01-01

    A 200-mg amount of bacampicillin showed a significantly higher relative extent of bioavailability than did a 250-mg amount of talampicillin, possibly due to their different stability in the digestive juices.

  10. 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.

  11. ENHANCED BIOAVAILABILITY OF DRUGS VIA INTRANASAL DRUG DELIVEY SYSTEM

    OpenAIRE

    kumar Brajesh; Shafat Kausar; Akhtar Ali; Prajapati S.K; Singh Devendra

    2012-01-01

    The aim of present investigation is to explain the enhancement of bioavailability of drug through intranasal drug delivery system. Intranasal Therapy has been an accepted form of treatment in the Ayurvedic system of Indian Medicine. Recently, it has been shown that many drugs have better bioavailability by nasal route than the oral route. This has been attributed to rich vasculature and a highly permeable structure of the nasal mucosa coupled with avoidance of hepatic first-pass elimination, ...

  12. Bioavailability of coffee polyphenols: focus on dose- and structure response

    OpenAIRE

    Erk, Thomas

    2014-01-01

    A positive affection of human health by nutrition is of high interest, especially for bioactive compounds which are consumed daily in high amounts. This is the case for chlorogenic acids (CGA) ingested by coffee. This molecule class is associated with several possible beneficial health effects observed in vitro that strongly depend on their bioavailability. So far factors influencing bioavailability of CGA such as dose, molecule structure and site of absorption haven´t been investigated suffi...

  13. Speciation dynamics and bioavailability of metals

    International Nuclear Information System (INIS)

    In this paper the equilibrium approach the so-called 'free-ion activity model' (FIAM) has been applied over and again in the interpretation of the bio-uptake of metals from complex media. One of the prerequisites of the FIAM is that the supply of the bioactive metal species, i.e. the free-ion, towards the surface of the organism is much faster than the actual bioconversion step. Only then will equilibrium between the different metal species in the medium be maintained at any point in space and time and hence will the bulk activity of the free-ion be maintained at the surface. However, there are numerous examples of metal bio-uptake from complex systems where the conversion rates cannot be understood in terms of the bioactive free-metal alone. In such cases it is mandatory that bio-inactive metal complexes contribute to the supply of metal to the bio-interface. Apparently, some complexes are able to dissociate at such a rate that the produced free-metal can significantly contribute to the metal flux towards the bio-surface. The mathematical characterization of the speciation dynamics and bioavailability of metals is discussed

  14. Bioavailability of caseinophosphopeptide-bound iron.

    Science.gov (United States)

    Ait-Oukhatar, Nabil; Peres, Jean Michel; Bouhallab, Said; Neuville, Dominique; Bureau, Francois; Bouvard, Gerard; Arhan, Pierre; Bougle, Dominique

    2002-10-01

    Iron deficiency, one of the main worldwide nutritional deficiencies, results from the low bioavailability of most dietary iron, including cow milk. Hydrolysis of the cow milk protein casein produces low molecular weight caseinophosphopeptides (CPPs). Binding of iron to CPPs keeps it soluble in the digestive tract and prevents the formation of high molecular weight ferric hydroxides, which are poorly absorbed. Previous experimental studies have shown that iron bound to the phosphopeptide containing the first 25 amino acids of beta-casein, or beta-CN (1-25), is well absorbed and corrects efficiently iron deficiency. We sought to assess in vivo iron absorption and uptake by tissues involved in iron metabolism and storage (liver, spleen, bone marrow), using radiolabeled iron. beta-CN (1-25)-Fe displayed better absorption and tissue uptake by the vascularized rat loop model compared with a control substance, ferric ascorbate. The metabolism of beta-CN (1-25)-Fe labeled with iron 59, added to cow milk, was also studied in young women. Although the absorption of beta-CN (1-25)-Fe was not significantly higher than that of ferrous sulfate, it displayed significantly higher tissue uptake. This increase was transient and had disappeared by the 14th day of the study, suggesting that iron was used for metabolic purposes. PMID:12389027

  15. Maltodextrin based proniosomes of nateglinide: bioavailability assessment.

    Science.gov (United States)

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

    2014-08-01

    The present study delineates the fabrication of maltodextrin based proniosomes of nateglinide and their potential as controlled delivery system for diabetic therapy. New Zealand albino male rabbits have been used as animal model for in vivo study. To evaluate the bioavailability of nateglinide proniosome, a rapid, simple and sensitive HPLC method with photodiode array detection was developed and validated to determine nateglinide in rabbit plasma. Chromatographic separation was achieved by a reverse phase C18 column using a mixture of acetonitrile:methanol:10mM phosphate buffer (pH 3.5) in the ratio of 56:14:30 (%v/v) as the mobile phase at a flow rate of 1.0ml/min and quantified based on drug/IS peak area ratios. Gliclazide was used as the internal standard. The intra- and inter-day relative standard deviations of four tested concentrations were below 2%. The nateglinide proniosome formulation exhibited significantly higher plasma concentration than those of pure drug. The study revealed that the rate and extent of absorption of nateglinide from the proniosomal formulation was comparatively enhanced that of pure drug. Maltodextrin based proniosomes of nateglinide is not only simple and cost efficient delivery but also offers a useful and promising carrier for diabetic therapy through oral administration. PMID:24909314

  16. Bioavailability of genotoxic mixtures in soil

    Energy Technology Data Exchange (ETDEWEB)

    Bordelon, N.; Washburn, K.; He, L.Y.; Donnelly, K.C. [Texas A and M Univ., College Station, TX (United States). Dept. of Veterinary Anatomy and Public Health

    1996-12-31

    Contaminated media at Superfund sites typically consist of complex mixtures of organic and inorganic chemicals which are difficult to characterize, both analytically and toxicologically. The current EPA approach to risk assessment uses solvent extraction to remove chemicals from the soil as a basis for estimating risk to the human population. However, contaminants that can be recovered with a solvent extract may not represent the mixture of chemicals that are available for human exposure. A procedure using an aqueous extraction was investigated to provide a more realistic estimate of what chemicals are bioavailable. A study was conducted with two soil types: creosote-contaminated sandy soil and coal tar-contaminated clay soil spiked with benzo(a)pyrene [B(a)P], and trinitrotoluene (TNT). Samples were extracted with hexane:acetone and water titrated to pH2 and pH7. HPLC analysis demonstrated up to 35% and 29% recovery of contaminants using the aqueous extracts. The estimated cancer risk for the aqueous extract was one order of magnitude less than that for solvent extracts. Analysis using the Salmonella/microsome assay demonstrated that solvent extracts were genotoxic (133 revertants/mg) with metabolic activation while aqueous extracts of clay soil were not genotoxic. Sandy soil showed genotoxicity both with and without metabolic activation. These results suggest that solvent extraction techniques may overestimate the concentration of contaminants that are available for human exposure and, hence, the risk associated with the presence of the contaminants in soil.

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

    International Nuclear Information System (INIS)

    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 logKows. The biota soil accumulation factors of PBDEs also declined with logKow. 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 logKows.

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

    Science.gov (United States)

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

    2016-01-01

    Trace metals are essential for the growth of anaerobic microorganisms, however, in practice they are often added to anaerobic digesters in excessive amounts, which can lead to inhibition. The concept of bioavailability of metals in anaerobic digestion has been poorly understood in the past, and a lack of deep understanding of the relationship between trace metal speciation and bioavailability can result in ineffective metal dosing strategies for anaerobic digesters. Sequential extraction schemes are useful for fractionating trace metals into their different forms, and metal sulfides can serve as a store and source for trace metals during anaerobic digestion, while natural/synthetic chelating agents (soluble microbial products-SMPs, extracellular polysaccharides-EPS, and EDTA/NTA) are capable of controlling trace metal bioavailability. Nevertheless, more work is needed to: investigate the speciation and bioavailability of Ca, Mg, Mn, W, and Se; compare the bioavailability of different forms of trace metals e.g. carbonates, sulfides, phosphates to different anaerobic trophic groups; determine what factors influence metal sulfide dissolution; investigate whether chelating agents can increase trace metal bioavailability; develop and adapt specialized analytical techniques, and; determine how trace metal dynamics change in an anaerobic membrane bioreactor (AnMBR). PMID:26707985

  19. 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 0.2μg/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. PMID:26969110

  20. Buccal films of prednisolone with enhanced bioavailability.

    Science.gov (United States)

    Kumria, Rachna; Nair, Anroop B; Goomber, Garima; Gupta, Sumeet

    2016-01-01

    The conventional formulation of prednisolone is considered to be low in efficacy, primarily on account of their failure in providing and maintaining effective therapeutic drug levels. This study aims to focus on development of a mucoadhesive buccal delivery system with a twofold objective of offering a rapid as well as a prolonged delivery of prednisolone coupled with enhanced therapeutic efficacy. Buccoadhesive films of prednisolone were prepared by solvent-casting method using hydroxyl propyl methyl cellulose (K100), Carbopol 940 and/or Eudragit NE 40 D. Placebo films possessing the most desirable physicomechanical properties were selected for drug loading. The effect of polymer and its content on film properties, i.e. mucoadhesive strength, swelling and hydration, in vitro drug release was studied. Based on these studies, film F7D was selected for ex vivo permeation across porcine cheek mucosa. The steady state flux of prednisolone across the buccal mucosa was found to be 105.33 ± 32.07 µg/cm(2)/h. A comparative pharmacokinetic study of prepared film (F7D) and oral suspension of prednisolone was conducted. In vivo data of buccal film show greater bioavailability (AUC0-α: 24.26 ± 4.06 µg.h/ml versus 10.65 ± 2.15 µg.h/ml) and higher Cmax (2.70 ± 0.38 µg/ml versus 2.29 ± 0.32 µg/ml) value when compared to oral suspension. The data observed from this study highlight the feasibility of the buccal route as a viable option for delivery of prednisolone. PMID:24892626

  1. Influence of biochar amendments on marine sediment trace metal bioavailability

    Science.gov (United States)

    Gehrke, G. E.; Hsu-Kim, H.

    2014-12-01

    Biochar has become a desirable material for use in agricultural application to enhance soil quality and in-situ soil and sediment remediation to immobilize organic contaminants. We investigated the effects of biochar sediment amendments on the bioavailability of a suite of inorganic trace metals (Cr, Co, Ni, Cu, Zn, Pb) in contaminated sediments from multiple sites in Elizabeth River, VA. We incubated sediments in microcosms with a variety of water column redox and salinity conditions and compared sediments amended with two types of woody biochar to sediments amended with charcoal activated carbon and unamended sediments. We leached sediments in artificial gut fluid mimic of the benthic invertebrate Arenicola marina as a measure of bioavailability of the trace metals analyzed. In unamended anaerobic sediments, the gut fluid mimic leachable fraction of each trace metal is 1-4% of the total sediment concentration for each metal. Initial results indicate that in anaerobic microcosms, woody biochar sediment amendments (added to 5% dry wt) decrease the gut fluid mimic leachable fraction by 30-90% for all trace metals analyzed, and have comparable performance to charcoal activated carbon amendments. However, in microcosms without controlled redox conditions, woody biochar amendments increase the bioavailable fraction of Ni and Cu by up to 80%, while decreasing the bioavailable fraction of Co, Zn, and Pb by approximately 50%; charcoal activated carbon amendments decreased the bioavailability of all trace metals analyzed by approximately 20%. In microcosms without an overlying water column, biochar and activated carbon amendments had no significant effects on trace metal bioavailability. This research demonstrates that biochar can effectively decrease the bioavailability of trace metals in marine sediments, but its efficiency is metal-specific, and environmental conditions impact biochar performance.

  2. 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. PMID:22609283

  3. Bioavailability enhancers of herbal origin:An overview

    Institute of Scientific and Technical Information of China (English)

    Kritika; Kesarwani; Rajiv; Gupta

    2013-01-01

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

  4. Bioavailability enhancers of herbal origin:An overview

    Institute of Scientific and Technical Information of China (English)

    Kritika Kesarwani; Rajiv Gupta

    2013-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

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

    International Nuclear Information System (INIS)

    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

  7. 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

  8. ENHANCED BIOAVAILABILITY OF DRUGS VIA INTRANASAL DRUG DELIVEY SYSTEM

    Directory of Open Access Journals (Sweden)

    kumar Brajesh

    2012-07-01

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

  9. Bioavailability of lead in rats fed human diets

    International Nuclear Information System (INIS)

    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 203Pb 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

  10. 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...

  11. Bioavailability of zinc from different Pakistani cereals grains

    International Nuclear Information System (INIS)

    The zinc has been determined by neutron activation analysis while phytate by spectrophotometric method in some Pakistani cereals grains. The zinc:phytate ratio is more than 40:1 in all cereal grains which is for more than the suggested binding ratio of 4:1. Therefore, bio-availability of zinc from Pakistan cereal grains is more than sufficient and no deficiency can be encountered due to bioavailability of zinc. The only deficiency of zinc which could happen, will be due to the pathological conditions. (author)

  12. 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.

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

    DEFF Research Database (Denmark)

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

    Production and bioavailability of dissolved organic matter was quantified on a time scale of two days from size fractions ranging from bacteria to zooplankton in the York River, Virginia. The goal was to find the main contributor to DOM. Batch incubation experiments were labeled with N15-ammonium...... mainly in the phytoplankton size fraction, which on average contributed 62 % of total particulate nitrogen and 61 % of total particulate carbon. Up to 5 ± 0.4 μmol dissolved organic nitrogen L-1 and 33 ± 6.2 μmol dissolved organic carbon L-1 was produced during the incubation. Bioavailability of...

  14. The bioavailability of an orally administered medroxyprogesterone acetate suspension.

    Science.gov (United States)

    Antal, E J; Gillespie, W R; Albert, K S

    1983-05-01

    The relative bioavailability of an orally administered aqueous suspension of medroxyprogesterone acetate (MPA) intended for intramuscular injection (Depo-Provera) was determined in relation to orally administered tablets. Serum levels of MPA were determined by radioimmunoassay following the administration of 400-mg doses to 19 adult male volunteers in a crossover design after an overnight fast. The two treatments were judged bioequivalent based upon a comparison of the resultant MPA serum levels and the derived bioavailability parameters. Hence, the intramuscular suspension administered orally offers an alternative means of achieving optimal serum levels of MPA in patients requiring high dose therapy. PMID:6222996

  15. Systems Biological Approach of Molecular Descriptors Connectivity: Optimal Descriptors for Oral Bioavailability Prediction

    OpenAIRE

    Ahmed, Shiek S. S. J.; Ramakrishnan, V.

    2012-01-01

    Background 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 ...

  16. Relative Bioavailability and Bioaccessibility and Speciation of Arsenic in Contaminated Soils

    OpenAIRE

    Bradham, Karen D.; Scheckel, Kirk G.; Nelson, Clay M.; Seales, Paul E.; Lee, Grace E.; Hughes, Michael F.; Miller, Bradley W.; Yeow, Aaron; Gilmore, Thomas; Serda, Sophia M.; Harper, Sharon; Thomas, David J

    2011-01-01

    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 m...

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

    International Nuclear Information System (INIS)

    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 (r2=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

  18. 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...

  19. 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...

  20. 21 CFR 320.38 - Retention of bioavailability samples.

    Science.gov (United States)

    2010-04-01

    ... Federal Food, Drug, and Cosmetic Act, or, if bioavailability testing was performed under contract, the... articles and reference standards and for the studies described: (1) If the formulation of the test article is the same as the formulation(s) used in the clinical studies demonstrating substantial evidence...

  1. 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.

  2. Effect of Attapulgite on The Oral Bioavailability of Ciprofloxacin

    Directory of Open Access Journals (Sweden)

    Zamrotul Izzah

    2013-06-01

    Full Text Available This study was aimed to determine the effect of attapulgite on the bioavailability of a single orallyadministered ciprofloxacin. Six New Zealand white rabbits received each of the following treatments in a randomized, three-way crossover sequence, separated by a 7-day washout period: (i ciprofloxacin (23 mg/kgBW alone; (ii ciprofloxacin (23 mg/kgBW given simultaneously with attapulgite (28 mg/ kgBW; (iii ciprofloxacin (23 mg/kgBW given 2 hours after attapulgite (28 mg/kgBW. Blood samples (1 mL were collected from the marginal ear vein up to 240 minutes postdose. The plasma concentrations of ciprofloxacin were determined by a validated high-performance liquid chromatography method. The maximum concentration and oral bioavailability (AUC0-240 min of ciprofloxacin were significantly decreased by 49 % and 32 % when administered concomitantly with attapulgite (p < 0.001. Attapulgite appeared to have no significant effect on the bioavailability of ciprofloxacin when administered 2 hours before ciprofloxacin. In conclusion, the oral bioavailability of ciprofloxacin was markedly reduced when administered concomitantly with attapulgite. This drug-drug interaction may decrease clinical efficacy and promote microbial resistance to ciprofloxacin. However, the interaction could be minimized by separating the adminsitration of these drugs at least 2 hours.

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

    NARCIS (Netherlands)

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

    2014-01-01

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

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

    International Nuclear Information System (INIS)

    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, MgCl2 (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

  5. 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

  6. [Enhancing of drug bioavailability using liquisolid system formulation].

    Science.gov (United States)

    Gajdziok, Jan; Vraníková, Barbora

    2015-06-01

    One of the modern technologies of how to ensure sufficient bioavailability of drugs with limited water solubility is represented by the preparation of liquisolid systems. The functional principle of these formulations is the sorption of a drug in a liquid phase to a porous carrier (aluminometasilicates, microcrystalline cellulose, etc.). After addition of further excipients, in particular a coating material (colloidal silica), a powder is formed with the properties suitable for conversion to conventional solid unit dosage forms for oral administration (tablets, capsules). The drug is subsequently administered to the GIT already in a dissolved state, and moreover, the high surface area of the excipients and their surface hydrophilization by the solvent used, facilitates its contact with and release to the dissolution medium and GI fluids. This technology, due to its ease of preparation, represents an interesting alternative to the currently used methods of bioavailability improvement. The article follows up, by describing the specific aspects influencing the preparation of liquid systems, on the already published papers about the bioavailability of drugs and the possibilities of its technological improvement.Key words: liquisolid systems bioavailability porous carrier coating material preformulation studies. PMID:26400228

  7. 21 CFR 320.28 - Correlation of bioavailability with an acute pharmacological effect or clinical evidence.

    Science.gov (United States)

    2010-04-01

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

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

    Science.gov (United States)

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

  9. 21 CFR 320.22 - Criteria for waiver of evidence of in vivo bioavailability or bioequivalence.

    Science.gov (United States)

    2010-04-01

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

  10. 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

  11. A meta-analysis to correlate lead bioavailability and bioaccessibility and predict lead bioavailability.

    Science.gov (United States)

    Dong, Zhaomin; Yan, Kaihong; Liu, Yanju; Naidu, Ravi; Duan, Luchun; Wijayawardena, Ayanka; Semple, Kirk T; Rahman, Mohammad Mahmudur

    2016-01-01

    Defining the precise clean-up goals for lead (Pb) contaminated sites requires site-specific information on relative bioavailability data (RBA). While in vivo measurement is reliable but resource insensitive, in vitro approaches promise to provide high-throughput RBA predictions. One challenge on using in vitro bioaccessibility (BAc) to predict in vivo RBA is how to minimize the heterogeneities associated with in vivo-in vitro correlations (IVIVCs) stemming from various biomarkers (kidney, blood, liver, urinary and femur), in vitro approaches and studies. In this study, 252 paired RBA-BAc data were retrieved from 9 publications, and then a Bayesian hierarchical model was implemented to address these random effects. A generic linear model (RBA (%)=(0.87±0.16)×BAc+(4.70±2.47)) of the IVIVCs was identified. While the differences of the IVIVCs among the in vitro approaches were significant, the differences among biomarkers were relatively small. The established IVIVCs were then applied to predict Pb RBA of which an overall Pb RBA estimation was 0.49±0.25. In particular the RBA in the residential land was the highest (0.58±0.19), followed by house dust (0.46±0.20) and mining/smelting soils (0.45±0.31). This is a new attempt to: firstly, use a meta-analysis to correlate Pb RBA and BAc; and secondly, estimate Pb RBA in relation to soil types. PMID:27104671

  12. Stability and bioavailability of mercury sulfide in Oak Ridge Soils

    International Nuclear Information System (INIS)

    During the 1950's and 1960's, a large amount of elemental mercury escaped confinement and is still present in the buildings and grounds of the U.S. Department of Energy's Y-12 National Security Facility and in the Y-12 Watershed in Oak Ridge, Tennessee, USA. Because of the adverse effects of elemental mercury and mercury compounds upon human health, the Oak Ridge Site is engaged in an on-going effort to monitor and remediate the area. In order to more cost effectively implement those extensive remediation efforts, it is necessary now to obtain an improved understanding of the role that mercury and mercury compounds play in the Oak Ridge ecosystem. Specifically, the long-term bioavailability, stability, and mobility of mercury species in contaminated terrestrial and aquatic environments of the Oak Ridge ecosystem under a range of biogeochemical conditions are not well understood. Mercury can be expected to be present in various forms. These species can be transformed from one form into another thus bioavailability, toxicity, and mobility can change as a function of the biogeochemical conditions. The kinetics of these transformations is currently unknown. We have conducted pilot scale experiments to study the bioavailability of mercury sulfide (HgS) in Oak Ridge soils. The effects of plants and incubation time on chemical stability and bioavailability of HgS under simulated conditions of the Oak Ridge ecosystem have been examined, as has the dynamics of the dissolution of HgS by various extractants. The results show that HgS in contaminated Oak Ridge soils was still to some extent bioavailable to plants. (authors)

  13. 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

    OpenAIRE

    Sips AJAM; van Eijkeren JCH.; 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, when it should appear that in this model bioavailability is overestimated by a factor 2 or more, this would imply that the present intervention values are 50% or more too low. This report gives an ...

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

    Science.gov (United States)

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

    2016-08-20

    In recent decades, many efforts have been made in order to improve drug bioavailability after oral administration. Gastroretentive drug delivery systems are a good example; they emerged to enhance the bioavailability and effectiveness of drugs with a narrow absorption window in the upper gastrointestinal tract and/or to promote local activity in the stomach and duodenum. Several strategies are used to increase the gastric residence time, namely bioadhesive or mucoadhesive systems, expandable systems, high-density systems, floating systems, superporous hydrogels and magnetic systems. The present review highlights some of the drugs that can benefit from gastroretentive strategies, such as the factors that influence gastric retention time and the mechanism of action of gastroretentive systems, as well as their classification into single and multiple unit systems. PMID:27173823

  15. Triple antioxidant SNEDDS formulation with enhanced oral bioavailability

    DEFF Research Database (Denmark)

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

    2016-01-01

    for the optimized formulation and free antioxidant suspension were performed. SNEDDS have significantly increased the Cmax and area under curve (AUC) of all three antioxidants. The SNEDDS demonstrated ~4.27 fold enhancement in oral bioavailability of quercetin, ~1.5 fold in case of resveratrol and ~2.8 fold in case......The present study aimed to develop quercetin, resveratrol and genistein loaded self-nanoemulsifying drug delivery system (SNEDDS) by QbD approach in order to improve their oral bioavailability and antioxidant potential. The size and PDI of the optimized formulation were found to be ... of genistein as compared to free antioxidants suspension. Finally, the prophylactic antitumor efficacy of developed formulation was tested against DMBA induced breast cancer model in rats, which demonstrated enhanced abeyance towards the tumor growth as compared to free antioxidants....

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

    Science.gov (United States)

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

    2014-12-28

    The dietary compound capsaicin is responsible for the "hot and spicy" taste of chili peppers and pepper extracts. It is a valuable pharmacological agent with several therapeutic applications in controlling pain and inflammation. Emerging studies show that it displays potent anti-tumor activity in several human cancers. On a more basic research level, capsaicin has been used as a ligand to activate several types of ion-channel receptors. The pharmacological activity of capsaicin-like compounds is dependent on several factors like the dose, the route of administration and most importantly on its concentration at target tissues. The present review describes the current knowledge involving the metabolism and bioavailability of capsaicinoids in rodents and humans. Novel drug delivery strategies used to improve the bioavailability and therapeutic index of capsaicin are discussed in detail. The generation of novel capsaicin-mimetics and improved drug delivery methods will foster the hope of innovative applications of capsaicin in human disease. PMID:25307998

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

    OpenAIRE

    WAJEEHA, F. H. KHAN AND I. JAVED

    2006-01-01

    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

  18. Rumen Microorganisms Decrease Bioavailability of Inorganic Selenium Supplements.

    Science.gov (United States)

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

    2016-06-01

    Despite the availability of selenium (Se)-enriched trace mineral supplements, we have observed low Se status in cattle and sheep offered traditional inorganic Se supplements. Reasons for this may include inadequate intake or low bioavailability of inorganic Se sources. The objective of this study was to determine whether rumen microorganisms (RMO) alter the bioavailability of Se sources commonly used in Se supplements. Rumen microorganisms were isolated from ewes (n = 4) and incubated ex vivo with no Se (control), with inorganic Na selenite or Na selenate, or with organic selenomethionine (SeMet). Total Se incorporated into RMO and the amount of elemental Se formed were determined under equivalent conditions. Incorporation of Se from Na selenite, Na selenate, or SeMet into RMO was measured as fold change compared with control (no added Se). Incorporation of Se into microbial mass was greater for SeMet (13.2-fold greater than no-Se control) compared with inorganic Se supplements (P = 0.02); no differences were observed between inorganic Na selenate (3.3-fold greater than no-Se control) and Na selenite (3.5-fold greater than no-Se control; P = 0.97). Formation of non-bioavailable, elemental Se was less for RMO incubated with SeMet compared with inorganic Se sources (P = 0.01); no differences were observed between Na selenate and Na selenite (P = 0.09). The clinical importance of these results is that the oral bioavailability of organic SeMet should be greater compared with inorganic Se sources because of greater RMO incorporation of Se and decreased formation of elemental Se by RMO. PMID:26537117

  19. Bioavailability in rats of metal adsorbed to soils

    International Nuclear Information System (INIS)

    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 75selenate (NaS), 63nickel chloride (NiCl) and 109cadmium 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

  20. Excipient Nanoemulsions for Improving Oral Bioavailability of Bioactives

    OpenAIRE

    Laura Salvia-Trujillo; Olga Martín-Belloso; David Julian McClements

    2016-01-01

    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 com...

  1. Bioavailability of nanoemulsified conjugated linoleic acid for an antiobesity effect

    OpenAIRE

    Kim D; Park JH; Kweon DJ; Han GD

    2013-01-01

    Dongyeop Kim,1,3* Jin-Hong Park,2* Dae-Jun Kweon,2 Gi Dong Han11Department of Food Science and Technology, College of Natural Resources, Yeungnam University, Gyeongsan, Republic of Korea; 2BioHealth Convergence Center, Daegu Technopark, Daegu, Republic of Korea; 3Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan *These authors contributed equally to this workBackground: The aim of this study was to enhance the bioavailability of conjugated lin...

  2. Elemental bioavailability in nutrient solutions in relation to precipitation reactions

    OpenAIRE

    De Rijck, G; Schrevens, Eddie

    1998-01-01

    In hydroponic plant nutritional research, nutrient solutions can be considered as aqueous solutions of inorganic ions. In this aqueous solution, the ions are submitted to the laws of aquatic inorganic chemistry. This means that the ions are involved in the dynamic equilibria between complexation, dissociation, and precipitation reactions. These chemical reactions seriously impact elemental speciation and bioavailability. As a result, plant roots experience a different nutritional composition....

  3. In Vitro Bioavailability of Mineral Nutrients in Breakfast Cereals

    OpenAIRE

    Anna Lesniewicz; Mariola Kretowicz; Kamila Wierzbicka; Wieslaw Zyrnicki

    2012-01-01

    The bioavailability of both micro- and macroelements was investigated under conditions simulating the digestion processes in the human alimentary system. A one-step enzymatic extraction was applied using buffered solutions containing pepsin, trypsin, alpha-amylase or pancreatin, which are enzymes that hydrolyse different nutritional food components such as peptides, carbohydrates and lipids, as the extractant. Corn flakes and multigrain breakfast cereals containing taste additives from a loca...

  4. Bioavailability and Population Pharmacokinetics of Voriconazole in Lung Transplant Recipients▿

    OpenAIRE

    Han, K.; Capitano, B.; Bies, R.; Potoski, B. A.; Husain, S.; Gilbert, S; Paterson, D. L.; McCurry, K.; Venkataramanan, R.

    2010-01-01

    This study was undertaken to characterize the pharmacokinetics and bioavailability of voriconazole in adult lung transplant patients during the early postoperative period, identify factors significantly associated with various pharmacokinetic parameters, and make recommendations for adequate dosing regimens. Thirteen lung transplant patients received two intravenous infusions (6 mg/kg, twice daily [b.i.d.]) immediately posttransplant followed by oral doses (200 mg, b.i.d.) for prophylaxis. Bl...

  5. Bioavailability of heavy metals in soils amended with sewage sludge

    OpenAIRE

    Morera Luzán, María Teresa; Echeverría Morrás, Jesús; Garrido Segovia, Julián José

    2002-01-01

    The recycling of sewage sludge to agricultural land results in the slow accumulation of potentially toxic heavy metals in soils. A greenhouse experiment was conducted to determine the bioavailability of Cu, Ni, Pb and Zn applied to soils in urban anaerobically stabilized sewage sludge. The soils were Lithic Haplumbrept (Lh), Calcixerollic Xerochrept (Cx1 and Cx2) and Paralithic Xerorthent (Px). Sunflower plants (Helianthus annuus L) were grown in. the soils following amendment with the slu...

  6. Bioavailability of metals from diesel exhaust using lung simulated fluids

    Czech Academy of Sciences Publication Activity Database

    Mikuška, Pavel; Coufalík, Pavel; Křůmal, Kamil; Vojtíšek, M.; Večeřa, Zbyněk

    Istambul: European Association for Chemical and Molecular Sciences, 2014. s. 702-702. [EuCheMS Chemistry Congress /5./. 31.08.2014-04.09.2014, Istanbul] R&D Projects: GA ČR GA13-01438S; GA ČR(CZ) GA14-25558S Institutional support: RVO:68081715 Keywords : bioavailability * diesel exhaust * emissions Subject RIV: CB - Analytical Chemistry, Separation

  7. 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

  8. Stable isotope studies of nicotine kinetics and bioavailability

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

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

    2016-08-01

    Acyclovir a BCS class III drug exhibits poor bioavailability due to limited permeability. The intention of this research work was to formulate and characterize thiolated xyloglucan polysaccharide nanoparticles (TH-NPs) of acyclovir with the purpose of increasing its oral bioavailability. Acyclovir-loaded TH-NPs were prepared using a cross-linking agent. Interactions of formulation excipients were reconnoitered using Fourier transform infrared spectroscopy (FT-IR). The formulated nanoparticles were lyophilised by the addition of a cryoprotectant and characterized for its particle size, morphology and stability and optimized using Box Behnken Design.The optimized TH-NP formulation exhibited particle size of 474.4±2.01 and an entrapment efficiency of 81.57%. A marked enhancement in the mucoadhesion was also observed. In-vivo study in a rat model proved that relative bioavailability of acyclovir TH-NPs is ∼2.575 fold greater than that of the marketed acyclovir drug suspension. PMID:27026342

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

    Science.gov (United States)

    Neff, Jerry M

    2008-04-01

    Drilling mud and associated drill cuttings are the largest volume wastes associated with drilling of oil and gas wells and often are discharged to the ocean from offshore drilling platforms. Barite (BaSO4) often is added as a weighting agent to drilling muds to counteract pressure in the geologic formations being drilled, preventing a blowout. Some commercial drilling mud barites contain elevated (compared to marine sediments) concentrations of several metals. The metals, if bioavailable, may harm the local marine ecosystem. The bioavailable fraction of metals is the fraction that dissolves from the nearly insoluble, solid barite into seawater or sediment porewater. Barite-seawater and barite-porewater distribution coefficients (Kd) were calculated for determining the predicted environmental concentration (PEC; the bioavailable fraction) of metals from drilling mud barite in the water column and sediments, respectively. Values for Kdbarite-seawater and Kdbarite-porewater were calculated for barium, cadmium, chromium, copper, mercury, lead, and zinc in different grades of barite. Log Kdbarite-seawater values were higher (solubility was lower) for metals in the produced water plume than log Kdbarite-porewater values for metals in sediments. The most soluble metals were cadmium and zinc and the least soluble were mercury and copper. Log Kd values can be used with data on concentrations of metals in barite and of barite in the drilling mud-cuttings plume and in bottom sediments to calculate PECseawater and PECsediment. PMID:17994916

  11. Bioavailability of zinc in runoff water from roofing materials.

    Science.gov (United States)

    Heijerick, D G; Janssen, C R; Karlèn, C; Wallinder, I Odnevall; Leygraf, C

    2002-06-01

    Corrosion and runoff from zinc-coated materials and outdoor structures is an important source for the dispersion of zinc in the environment. Being part of a large inter-disciplinary research project, this study presents the bioavailability of zinc in runoff water immediately after release from the surface of 15 different commercially available zinc-based materials exposed to the urban environment of Stockholm, Sweden. Runoff water was analysed chemically and evaluated for its possible environmental impact, using both a biosensor test with the bacteria Alcaligenes eutrophus (Biomet) and the conventional 72 h growth inhibition test with the green alga Raphidocelis subcapitata. Chemical speciation modelling revealed that most zinc (94.3-99.9%) was present as the free Zn ion, the most bioavailable speciation form. These findings were confirmed by the results of the biosensor test (Biomet) which indicated that all zinc was indeed bioavailable. Analysis of the ecotoxicity data also suggested that the observed toxic effects were due to the presence of Zn2+ ions. Finally, regression analysis showed that, for this type of runoff samples, the rapid screening biosensor was capable of predicting (a) the total amount of zinc present in the runoff samples (R2 of 0.93-0.98; p < 0.05) and (b) the observed 72 h-EbC50s (R2 of 0.69-0.97; p < 0.05). PMID:12137040

  12. Accounting for differences in the bioactivity and bioavailability of vitamers

    Directory of Open Access Journals (Sweden)

    Jesse F. Gregory

    2012-04-01

    Full Text Available Essentially all vitamins exist with multiple nutritionally active chemical species often called vitamers. Our quantitative understanding of the bioactivity and bioavailability of the various members of each vitamin family has increased markedly, but many issues remain to be resolved concerning the reporting and use of analytical data. Modern methods of vitamin analysis rely heavily on chromatographic techniques that generally allow the measurement of the individual chemical forms of vitamins. Typical applications of food analysis include the evaluation of shelf life and storage stability, monitoring of nutrient retention during food processing, developing food composition databases and data needed for food labeling, assessing dietary adequacy and evaluating epidemiological relationships between diet and disease. Although the usage of analytical data varies depending on the situation, important issues regarding how best to present and interpret the data in light of the presence of multiple vitamers are common to all aspects of food analysis. In this review, we will evaluate the existence of vitamers that exhibit differences in bioactivity or bioavailability, consider when there is a need to address differences in bioactivity or bioavailability of vitamers, and then consider alternative approaches and possible ways to improve the reporting of data. Major examples are taken from literature and experience with vitamin B6 and folate.

  13. Bioavailability of mercury in East Fork Poplar Creek soils

    International Nuclear Information System (INIS)

    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

  14. 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.

  15. Proceedings: ISEA Bioavailability Symposium, Durham, North Carolina Use of InVitro Bioaccessibility/Relative Bioavailability Estimates for Metals in Regulatory Settings: What is Needed?

    Science.gov (United States)

    Oral ingestion of soil and dust is a key pathway for human exposures to metal and metalloid contaminants. It is widely recognized that the site-specific bioavailability of metals in soil and dust may be reduced relative to the metal bioavailability in media such as water and food...

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

    International Nuclear Information System (INIS)

    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, CaCl2 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.

  17. ENHANCEMENT OF ORAL BIOAVAILABILITY OF LIPOPHILLIC DRUGS FROMSELF-MICROEMULSIFYING DRUG DELIVERY SYSTEM (SMEDDS)

    OpenAIRE

    GUPTA ROOP N1, GUPTA RAKESH AND RATHORE GARVENDRA SINGH*

    2009-01-01

    Approximately 40 per cent of new drug candidates have poor water solubility and the oral delivery of such drugs isfrequently associated with implications of low bioavailability, high intra and inter-subject variability, and lack of doseproportionality. Bioavailability problem of lipophillic drugs can be solved by formation of Self-Micro Emulsifying DrugDelivery System (SMEDDS). SMEDDS appears to be a unique and industrially feasible approach to overcome theproblem of low oral bioavailability ...

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

    OpenAIRE

    Tatiana Christides; Francis Kweku Amagloh; Jane Coad

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

  20. Enhanced dissolution and bioavailability of gliclazide using solid dispersion techniques

    Directory of Open Access Journals (Sweden)

    Gopal Venkatesh Shavi

    2011-04-01

    Full Text Available

    Gliclazide is practically insoluble in water and its bioavailability is limited by dissolution rate. To enhance the dissolution rate and bioavailability the present study was aimed to formulate solid dispersions using different water soluble polymers such as polyethylene glycol 4000 (PEG 4000, polyethylene glycol 6000 (PEG 6000 using fusion method and polyvinyl pyrrolidone K- 30 (PVP K 30 by solvent evaporation method. The interaction of gliclazide with the hydrophilic polymers was studied by Differential Scanning Calorimetry (DSC, Fourier Transformation-Infrared Spectroscopy (FTIR and X-Ray diffraction analysis. Solid dispersions were characterized for physicochemical properties like drug content, surface morphology and dissolution studies. Various factors like type of polymer and ratio of the drug to polymer on the solubility and dissolution rate of the drug were also evaluated. Pharmacokinetic studies of optimized formulation were compared with pure drug and marketed formulation in wistar rats. The dissolution of the pure drug and solid dispersion prepared with PVP K 30 (1:1 showed 38.3 + 4.5 % and 95 + 5.2 % release respectively within 30 min. Peak plasma concentration of pure drug, solid dispersion (PVP K 30 and marketed formulation was found to be 8.76 + 2.5, 16.04 + 5.5 and 9.24 + 3.6 μg/ml respectively, from these results it was observed that there is two fold increase in peak plasma concentration compared to pure drug. Solid dispersion is an effective technique in increasing solubility, dissolution rate and bioavailability of the poorly soluble drugs.

    Keywords: Gliclazide; solubility; solid dispersion; pharmacokinetics; peak plasma concentration; half life

  1. 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.

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

    International Nuclear Information System (INIS)

    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. Study of paracetamol 1-g oral solution bioavailability.

    Science.gov (United States)

    Farre, M; Roset, P N; Abanades, S; Menoyo, E; Alvarez, Y; Rovira, M; Baena, A

    2008-01-01

    The aim of this work was to assess paracetamol bioavailability after administering 1 g in oral solution. Eighteen healthy volunteers were selected for this open-label study. A total of 15.4 ml of Gelocatil Oral Solution (Laboratorios Gelos, S.L.), corresponding to 1 g of paracetamol, were administered to fasting subjects. Blood samples were collected at 0 min, 10 min, 20 min, 30 min, 45 min, 1 h, 1.5 h, 2 h, 3 h, 4 h, 6 h, 8 h, 10 h and 12 h. Paracetamol plasma concentrations were determined by reverse-phase high-performance liquid chromatography. The study was conducted without deviations from protocol. Pharmacokinetic data from 18 subjects were allowed for estimating fast and high-paracetamol bioavailability: t(max) 20 min (10-45) [median (range)], C(max) 24. 3 mg/l (6.5) [mean (standard deviation)], AUC(0-t) 64.0 mg h/l (16.1) and AUC(0-00) 68.1 mg h/l (17.9). These results are comparable to those described for Gelocatil Oral Solution given at a 650 mg dose and for immediate release Gelocatil 650 mg tablets. Absorption speed was very fast, similar to that described for other oral-solution formulations, which provides an immediate onset of pain and fever relief. The results of this study show suitable bioavailability for 1 g Gelocatil Oral Solution, with fast-absorption speed that provides an immediate onset of pain and fever relief. PMID:18389096

  4. Iodine speciation and bioavailability in edible seaweeds harvested in Galicia

    OpenAIRE

    Romarís Hortas, Vanessa

    2013-01-01

    This work has been developed in the context of a region with a recent industry of seaweeds for human consumption. It is well known that algae are one of the organisms containing the highest concentrations of iodine (I), an essential trace element for humans. Nevertheless there is still a lack of information about the nature of the iodinated compounds present in algae and on their bioavailability. The main objectives of this PhD thesis were to study in depth the I content from edible seaweeds ...

  5. Effect of renal function on the bioavailability of ciprofloxacin.

    OpenAIRE

    Plaisance, K I; Drusano, G. L.; Forrest, A.; Weir, M R; Standiford, H C

    1990-01-01

    The effect of renal function on the bioavailability of ciprofloxacin was studied in 21 subjects with measured creatinine clearances ranging from 0 to 8.99 liters/h per 1.73 m2. Each subject received ciprofloxacin, 200 mg intravenously and 750 mg orally, separated by at least 1 week. Serial (12 to 15) blood samples were obtained over 24 to 48 h. Concentrations in serum were assayed by high-pressure liquid chromatography. Area under the curve was calculated by the trapezoidal rule with extrapol...

  6. Bioavailability of the antiemetic metopimazine given as a microenema

    DEFF Research Database (Denmark)

    Herrstedt, J.; Jørgensen, M.; Angelo, H.R.; Rassing, M.R.; Sonnergaard, Jørn; Dombernowsky, P.

    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....

  7. Evaluation of bioavailability of food fortificants using stable isotopic methods

    International Nuclear Information System (INIS)

    Because of the complex biochemical processes affecting the bioavailability of micronutrients, it is critical to understand regional factors that affect the design of a nutritional supplementation strategy. These factors include the prevalence of multiple micronutrient deficiencies, the presence of inhibitors in indigenous foods, interactions among co-fortificants, and coexisting medical diseases affecting absorptive capacity. Each of these can lessen the bioavailability, and thus the effectiveness, of supplements. Stable isotopic studies can help determine the fate of ingested micronutrients; therefore, they can evaluate the efficacy of fortification programs, provide evidence of poor bioavailability, and point to potential remedies. This has been the focus of several recent investigations by the Baylor Stable Isotope Laboratory and a proposed project in Sri Lanka. In Indonesia an efficacy study evaluated the current program of iron fortification of flour and the proposed addition of zinc. Three groups of 30 children ages 4 to 8 were given supplemented flour (iron only, iron plus zinc sulfate, iron plus zinc oxide). Each group exhibited iron absorption of greater than 10%, but concomitant zinc administration decreased iron bioavailability. This decrease was only statistically significant for zinc sulfate, however. Zinc absorption exceeded 20% in both the zinc oxide and zinc sulfate groups. In Peru four groups of one-year old children were given supplemented rolls containing iron, iron plus vitamin A, iron plus zinc, and iron plus zinc plus vitamin A. Isotopic analysis demonstrated that iron absorption was significantly better with the addition of vitamin A, marginally worse when zinc was included, and nearly equivalent when the three supplements were given in combination. Another recent study in Peru demonstrated the efficacy of a beverage fortified with multiple micronutrients in school age children. This investigation showed that balanced micronutrient

  8. Ageing of vanadium in soils and consequences for bioavailability

    OpenAIRE

    Baken, Stijn; Larsson, M. A.; Gustafsson, J. P; Cubadda, F.; Smolders, Erik

    2012-01-01

    Total vanadium (V) concentrations in soils commonly range from 20 to 120 mg kg-1. Vanadium added directly to soils is more soluble than geogenic V and can be phytotoxic at doses within this range of background concentrations. However, it is unknown how slow sorption reactions change the fate and effect of added V in soils. This study addresses the changes in V solubility, toxicity and bioavailability in soils over time. Four soils were amended with pentavalent V in the form of a soluble vanad...

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

    International Nuclear Information System (INIS)

    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

  10. Effect of Attapulgite on The Oral Bioavailability of Ciprofloxacin

    OpenAIRE

    Zamrotul Izzah; Veronica Gratia; Toetik Aryani; Suharjono

    2013-01-01

    This study was aimed to determine the effect of attapulgite on the bioavailability of a single orallyadministered ciprofloxacin. Six New Zealand white rabbits received each of the following treatments in a randomized, three-way crossover sequence, separated by a 7-day washout period: (i) ciprofloxacin (23 mg/kgBW) alone; (ii) ciprofloxacin (23 mg/kgBW) given simultaneously with attapulgite (28 mg/ kgBW); (iii) ciprofloxacin (23 mg/kgBW) given 2 hours after attapulgite (28 mg/kgBW). Blood s...

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

    International Nuclear Information System (INIS)

    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

  12. Vanadium bioavailability in soils amended with blast furnace slag

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2015-10-15

    Blast furnace (BF) slags are commonly applied as soil amendments and in road fill material. In Sweden they are also naturally high in vanadium. The aim of this study was to assess the vanadium bioavailability in BF slags when applied to soil. Two soils were amended with up to 29% BF slag (containing 800 mg V kg(-1)) and equilibrated outdoors for 10 months before conducting a barley shoot growth assay. Additional soil samples were spiked with dissolved vanadate(V) for which assays were conducted two weeks (freshly spiked) and 10 months (aged) after spiking. The BF slag vanadium was dominated by vanadium(III) as shown by V K-edge XANES spectroscopy. In contrast, results obtained by HPLC-ICP-MS showed that vanadium(V), the most toxic vanadium species, was predominant in the soil solution. Barley shoot growth was not affected by the BF slag additions. This was likely due to limited dissolution of vanadium from the BF slag, preventing an increase of dissolved vanadium above toxic thresholds. The difference in vanadium bioavailability among treatments was explained by the vanadium concentration in the soil solution. It was concluded that the vanadium in BF slag is sparingly available. These findings should be of importance in environmental risk assessment. PMID:25917693

  14. 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.

  15. Pharmaceutical and pharmacological approaches for bioavailability enhancement of etoposide

    Indian Academy of Sciences (India)

    Ishtiyaq Ahmad Najar; Rakesh Kamal Johri

    2014-03-01

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

  16. 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. PMID:25526673

  17. Functionalized Polymers for Enhance Oral Bioavailability of Sensitive Molecules

    Directory of Open Access Journals (Sweden)

    Yolanda Alvarado Pérez

    2016-06-01

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

  18. Speciation and bioavailability of zinc in amended sediments

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-12-09

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

  19. 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.

  20. Pharmacokinetics, oral bioavailability and tissue distribution of azithromycin in cats.

    Science.gov (United States)

    Hunter, R P; Lynch, M J; Ericson, J F; Millas, W J; Fletcher, A M; Ryan, N I; Olson, J A

    1995-02-01

    Azithromycin is the first of a class of antibiotics classified as azalides. In an initial experiment four cats were given a single dose of azithromycin 5 mg/kg orally (p.o.), followed 2 weeks later by a single intravenous bolus (i.v.) dose of 5 mg/kg. Subsequently, six cats were given [14C]azithromycin p.o. in a single dose of 5.4 mg/kg for the study of tissue distribution and metabolism. In both experiments, serial blood samples were collected and the plasma assayed for unchanged azithromycin to determine various pharmacokinetic parameters. After p.o. administration, bioavailability was 58% and absorption rapid with a tmax of 0.85 +/- 0.72 h and a Cmax of 0.97 +/- 0.65 microgram/mL. The harmonic mean terminal t1/2 after i.v. administration was 35 h. Tissue half-lives varied from 13 h in fat to 72 h in cardiac muscle. Three metabolites were identified in bile. Unchanged azithromycin accounted for 100% of the total radioactivity in lung and skin tissues when assayed. In comparison with other species, the bioavailability in cats is higher than in humans but lower than in dogs. As in the dog, > 50% of the azithromycin-related material in feline bile was unchanged azithromycin. PMID:7752305

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

    Science.gov (United States)

    Brglez Mojzer, Eva; Knez Hrnčič, Maša; Škerget, Mojca; Knez, Željko; Bren, Urban

    2016-01-01

    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. PMID:27409600

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

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

    2014-04-01

    Several strategies appear suitable to improve iron and zinc bioavailability from fortified maize, and fortification per se will increase the intake of bioavailable iron and zinc. Corn masa flour or whole maize should be fortified with sodium iron ethylenediaminetetraacetate (NaFeEDTA), ferrous fumarate, or ferrous sulfate, and degermed corn flour should be fortified with ferrous sulfate or ferrous fumarate. The choice of zinc fortificant appears to have a limited impact on zinc bioavailability. Phytic acid is a major inhibitor of both iron and zinc absorption. Degermination at the mill will reduce phytic acid content, and degermed maize appears to be a suitable vehicle for iron and zinc fortification. Enzymatic phytate degradation may be a suitable home-based technique to enhance the bioavailability of iron and zinc from fortified maize. Bioavailability experiments with low phytic acid-containing maize varieties have suggested an improved zinc bioavailability compared to wild-type counterparts. The bioavailability of folic acid from maize porridge was reported to be slightly higher than from baked wheat bread. The bioavailability of vitamin A provided as encapsulated retinyl esters is generally high and is typically not strongly influenced by the food matrix, but has not been fully investigated in maize. PMID:24329552

  4. Low Thermal Pretreatment as Method for Increasing the Bioavailability of Organic Matters in Domestic Mixed Sludge

    OpenAIRE

    Seswoya Roslinda; Abdul Karim Ahmad Tarmizi

    2016-01-01

    In practice, primary and secondary sludge are fed into anaerobic digestion. However, the microbial cell exists in secondary sludge are an unfavorable substrate for biodegradation. Thermal pretreatment is proved to increase the bioavailability of organic and improve the biodegradation subsequently. During low thermal pretreatment, both intracellular (within the microbial cell) and extracellular (within the polymeric network) materials were extracted. This process increases the bioavailability ...

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

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  7. Nanoparticle Formulation Increases Oral Bioavailability of Poorly Soluble Drugs: Approaches Experimental Evidences and Theory

    OpenAIRE

    Jia, Lee

    2005-01-01

    The increasing frequency at which poorly soluble new chemical entities are being discovered raises concerns in the pharmaceutical industry about drugability associated with erratic dissolution and low bioavailability of these hydrophobic compounds. Nanonization provides a plausible pharmaceutical basis for enhancing oral bioavailability and therapeutic effectiveness of these compounds by increasing their surface area. This paper surveys methods available to pharmaceutical manufacturing nanopa...

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

    International Nuclear Information System (INIS)

    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. Comparative bioavailability study of two brands of prazosin-containing tablets in healthy volunteers.

    Science.gov (United States)

    Guelen, P J; Janssen, T J; Lam, M H; Vree, T B; Exler, P S

    1990-10-19

    The bioavailability of two prazosin formulations was studied in 12 healthy volunteers. 1 Subject left the study. Based on the statistical tests of the pharmacokinetic parameters of prazosin in 11 volunteers, such as t 1/2, Cmax, tmax and AUC, it could be concluded that both preparations had comparable bioavailabilities. PMID:2255586

  10. 21 CFR 320.29 - Analytical methods for an in vivo bioavailability or bioequivalence study.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Analytical methods for an in vivo bioavailability... Analytical methods for an in vivo bioavailability or bioequivalence study. (a) The analytical method used in... ingredient or therapeutic moiety, or its active metabolite(s), achieved in the body. (b) When the...

  11. 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...

  12. Bioavailability of Anthocyanins from Purple Carrot Juice: Effects of Acylation and Plant Matrix

    Science.gov (United States)

    Bioavailability of anthocyanins from juiced purple carrots was investigated through a human feeding study. Ten healthy adults consumed three doses of purple carrot juice, and bioavailability was assessed by appearance of anthocyanins in plasma for 8 hours after the dose. Doses were 50 mL, 150 mL, ...

  13. High absolute bioavailability of methylene blue given as an aqueous oral formulation

    OpenAIRE

    Walter-Sack, Ingeborg; Rengelshausen, Jens; Oberwittler, Heike; Burhenne, Juergen; Mueller, Olaf; Meissner, Peter; Mikus, Gerd

    2008-01-01

    Abstract Purpose Methylene blue (MB) has recently been reevaluated for malaria treatment. With the aim of excluding treatment failures due to low bioavailability, we have investigated the absolute bioavailability of MB given as an aqueous oral formulation and its interaction with chloroquine (CQ). Methods A phase...

  14. 21 CFR 320.21 - Requirements for submission of bioavailability and bioequivalence data.

    Science.gov (United States)

    2010-04-01

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

  15. 21 CFR 320.24 - Types of evidence to measure bioavailability or establish bioequivalence.

    Science.gov (United States)

    2010-04-01

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

  16. 21 CFR 320.23 - Basis for measuring in vivo bioavailability or demonstrating bioequivalence.

    Science.gov (United States)

    2010-04-01

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

  17. 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...

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

    International Nuclear Information System (INIS)

    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

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

    DEFF Research Database (Denmark)

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

    2000-01-01

    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...... did not change during the first 3 d and coincided with increased degrees of resistance and a decrease in diversity. The concentration of bioavailable mercury decreased subsequently rapidly and remained just above the detection level (0.2 ng g-1) for the remainder of the experiment. As a possible...

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

    Directory of Open Access Journals (Sweden)

    Tatiana Christides

    2015-09-01

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

  1. Relative Bioavailability of Scopolamine Dosage Forms and Interaction with Dextroamphetamine

    Science.gov (United States)

    Boyd, Jason L.; Du, Brian; Vaksman, Zalman; Locke, James P.; Putcha, Lakshmi

    2007-01-01

    The NASA Reduced Gravity Office (RGO) uses scopolamine (SCOP) and in combination with dextoamphetamine (DEX) to manage motion sickness symptoms during parabolic flights. The medications are dispensed as custom dosage forms as gelatin capsules. Anecdotal evidence of efficacy suggests that these formulations are unreliable and less efficacious for the treatment of motion sickness. We estimated bioavailability of four different oral formulations used by NASA for the treatment of motion sickness. Twelve healthy, non-smoking subjects between 21and 48 years of age received four treatments on separate days in a randomized fashion; the treatments were 0.8 mg SCOP alone as tablet, 0.8 mg SCOP alone in gel cap, 0.8 mg SCOP and 10 mg DEX as tablets, and 0.8 mg SCOP and 10 mg DEX in gel cap. After each treatment, blood, saliva, and urine samples were collected at scheduled time intervals for 24 h after dosing. Bioavailability and pharmacokinetic parameters were calculated and compared using ANOVA. After administration of SCOP tablets alone, maximum concentration (C(sub max)) and time for maximum concentration (t(sub max)) were 0.26 plus or minus 0.04 ng/mL and 0.71 plus or minus 0.02 h, respectively; volume of distribution, and clearance were 47.6 plus or minus 4.72 L/kg and 23.0 plus or minus 4.58 L/h/kg, respectively. SCOP t(sub max) after administration as gelcaps was significantly longer than that with tablets (1.04 h, p less than 0.05), but no significant differences in other pharmacokinetic parameters of SCOP were observed between the two dosage forms. When coadministered with DEX, the area underneath the concentration versus time curve (AUC) of SCOP was significantly reduced to 0.61 plus or minus 0.09 and 0.64 plus or minus 0.11 ng (raised dot) h/mL after administration as a tablet or gelcap formulation, respectively; SCOP C(sub max) was lower after coadministration with DEX, this difference, however, was not statistically significant. Delayed absorption with gelcaps

  2. Bioavailability of cadmium from infant diets in newborn rats

    International Nuclear Information System (INIS)

    Infants are exposed to higher levels of cadmium (Cd) from infant and follow-on formulas than from breast milk. We studied the bioavailability of 109CdCl2 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 109Cd, 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 109Cd in the whole body, in segments of rinsed small intestine and in tissue was measured in a gamma counter. Pups receiving 109Cd 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 109Cd 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 109Cd 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, 109Cd 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 109Cd 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 109Cd 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 order to

  3. 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.

  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. 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 §...

  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

    ... bioavailability or bioequivalence study. 320.26 Section 320.26 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 §...

  7. Long-term changes in cadmium bioavailability in soil

    Energy Technology Data Exchange (ETDEWEB)

    Hamon, R.E. [Univ. of Adelaide, Urrbrae, South Australia (Australia). Dept. of Soil Science]|[Cooperative Research Centre for Soil and Land Management, Glen Osmond, South Australia (Australia); McLaughlin, M.J.; Naidu, R. [Cooperative Research Centre for Soil and Land Management, Glen Osmond, South Australia (Australia)]|[CSIRO Div. of Land and Water, Glen Osmond, South Australia (Australia); Correll, R. [CSIRO Div. of Land and Water, Glen Osmond, South Australia (Australia)

    1998-12-01

    A study was conducted to examine changes in total and phytoavailable Cd in a soil that had received inputs of Cd due to fertilization with single superphosphate (SSP) at various rates since 1948. Accumulation of Cd in the soil was highly correlated to the application rate of SSP. No evidence was found to indicate offsite movement of Cd, either through horizontal transfer or via leaching through the profile. Increases in soil Cd led to an increase in the Cd content of wheat that was grown in the soil. However, using a radioisotope dilution technique, a significant proportion of the added Cd was found to exist in a non-bioavailable pool in the soil. A model was developed which estimated that Cd was being fixed in this soil at a rate of 1--1.5% of the total added Cd per year.

  8. Long term changes in Cadmium bioavailability in soil

    International Nuclear Information System (INIS)

    A study was conducted to examine changes in total and phytoavailable Cd in a soil, which had received inputs of Cd due to fertilization with single superphosphate (SSP) at various rates since 1948. Accumulation of Cd in the soil was highly correlated to application rate of SSP. No evidence was found to indicate offsite movement of Cd, either through horizontal transfer or via leaching through the profile. Increases in soil Cd led to an increase in the Cd content of wheat, which was grown in the soil. However, using a radioisotope dilution technique, a significant proportion of the added Cd was found to exist in a non-bioavailable pool in the soil. A model was developed which estimated that Cd was being fixed in this soil at a rate of 1 to 1.5 % of total Cd added per year. (author)

  9. Bioavailability of energy-effluent materials in coastal ecosystems

    International Nuclear Information System (INIS)

    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

  10. Bloat free genetic programming: application to human oral bioavailability prediction.

    Science.gov (United States)

    Silva, Sara; Vanneschi, Leonardo

    2012-01-01

    Being able to predict the human oral bioavailability for a potential new drug is extremely important for the drug discovery process. This problem has been addressed by several prediction tools, with Genetic Programming providing some of the best results ever achieved. In this paper we use the newest developments of Genetic Programming, in particular the latest bloat control method, Operator Equalisation, to find out how much improvement we can achieve on this problem. We show examples of some actual solutions and discuss their quality, comparing them with previously published results. We identify some unexpected behaviours related to overfitting, and discuss the way for further improving the practical usage of the Genetic Programming approach. PMID:23356009

  11. Pharmacokinetics and Relative Bioavailability of Levothyroxine sodium Tablets By RIA

    International Nuclear Information System (INIS)

    The pharmacokinetics and relative bioavailability of two kinds of domestic levothyroxine sodium tablets containing 50μg or 100μg per unit were studied in comparison with imported Euthyrox 100 containing 100μg levothyroxine sodium by Radioimmunoassay. According to open and randomized principle, 21 healthy male volunteers received in three times cross-over clinical trial using a single oral doses of 600 μg of levothyroxine sodium and their serum drug concentration were determined. An analysis of variance and two one-sided t-test were performed to evaluate the bioequivalence of domestic and imported tablets. The study results indicated that the Radioimmunoassay methods applied in this study are appropriate and showed two domestic levothyroxine sodium preparations and Euthyrox 100 are bioequivalent

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

    DEFF Research Database (Denmark)

    Weis, M.; Mortensen, S.A.; Rassing, M.R.; Sonnergaard, Jørn; Poulsen, G.; Rasmussen, S.N.

    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......: 100 mg of CoQ with 400 mg of soy bean oil (Bioquinon); 100 mg of CoQ with 20 mg of polysorbate 80, 100 mg of lecithin and 280 mg of soy bean oil; and 100 mg of CoQ with 20 mg of polysorbate 80 and 380 mg of soy bean oil, respectively. The result suggests that the soya bean oil suspension of Co...

  13. Determination of bioavailable rhenium fraction in agricultural soils

    International Nuclear Information System (INIS)

    Rhenium (Re) mobility in agricultural soils was studied in order to obtain information relevant to 99Tc mobility in soil-to-plant systems. Since water soluble Tc and Re are highly bioavailable, extraction of Re with water was carried out in addition to a total Re determination in the soils. The geometric means of total Re for paddy field, upland field and other soils were 0.34, 0.23, and 0.28 ng g-1, respectively, while those of water soluble Re (-1, respectively. There were no differences for total Re among soil uses; however, the water soluble Re/total Re ratio was significantly higher in paddy field soils (16%) than in other soil uses (6% for upland fields and 3% for other uses). Rhenium mobility and plant availability were higher in paddy fields than in other agricultural fields, and similar phenomena would be expected for 99Tc

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

    International Nuclear Information System (INIS)

    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 × 105 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

  15. Quantitative assessment of radiocaesium bioavailability in forest soils

    International Nuclear Information System (INIS)

    A method for quantitative characterisation of the radiocaesium availability to plants in forest ecosystems has been developed. For this purpose an expression has been proposed to calculate the radiocaesium availability factor in soils, which is a combination of key soil characteristics: radiocaesium exchangeability, exchangeable calcium in soil and effective selectivity coefficient. The experimental dependencies of the radiocaesium soil to plant concentration factors for fern and bilberry, on the availability factor calculated by the above equation were satisfactory described by linear function. The advantage of this method to characterise bioavailability of radiocaesium and to estimate site-specific values of concentration factor is that the necessary soil characteristics may be taken from the reference literature, evaluated by experts or determined with a simple experimental procedure. The method can be used in development of a radioecological geographic information systems. (orig.)

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

    Science.gov (United States)

    Kamil, Alison

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

  17. Oral absorption and bioavailability of flumequine in veal calves.

    Science.gov (United States)

    Mevius, D J; Breukink, H J; Jansen, T; Guelen, P J; de Grève, B

    1989-10-01

    The oral absorption and bioavailability of flumequine was studied in 1-, 5- and 18-week-old calves following intravenous and oral administration of different formulations of flumequine (Flumix, Flumix C and pure flumequine). Increasing age had a negative influence on the Cmax after the administration of Flumix, based on a larger VD in the older calves. The Cmax decreased from 5.02 +/- 1.46 micrograms/ml in the first week to 3.28 +/- 0.42 micrograms/ml in the 18th week. Adding colistin sulfate to the flumequine formulation and administring pure flumequine mixed with milk replacer had a negative effect on the Cmax of flumequine after oral administration of 5 and 10 mg/kg body weight. The bioavailability of the orally administered flumequine formulations was 100% in all cases except after the administration of Flumix C, for which it was 75.9 +/- 18.2%. The urinary recovery of flumequine after intravenous injection of a 10% solution varied from 35.2 +/- 2.3% for Group B, to 41.2 +/- 6.3% for Group C. The dosage of 5 mg/kg body weight Flumix twice daily in 1-week-old veal calves is sufficient to reach therapeutic plasma concentrations, based on a MIC value of 0.8 micrograms/ml of the target bacteria. In older calves it is advisable to increase the dosage 7.5 or 10 mg/kg body weight every 12 hours. In combination with colistin sulfate it is also advisable to increase the dosage slightly because of the negative effect of the colistin sulfate on the Cmax of flumequine. PMID:2603356

  18. Pharmacokinetics and relative bioavailability of levothyroxine sodium tablets by RIA

    International Nuclear Information System (INIS)

    Objective: The pharmacokinetics and relative bioavailability of two kinds of domestic levothyroxine sodium tablets containing 50 μg or 100 μg per unit were studied in comparison with imported Euthyrox 100 containing 100 μg levothyroxine sodium by Radioimmunoassay. Methods; According to open and randomized principle, 21 healthy male volunteers received in three times cross-over clinical trial using a single oral doses of 600 μg of levothyroxine sodium and their serum drug concentration were determined. An analysis of variance and two one-sided t-test were performed to evaluate the bioequivalence of domestic and imported tablets. Results: The results showed that the AUC values of studied medicine were 10.13±1.84 nmol·h·ml-1 and 10.30±1.42 nmol·h·ml-1, the Cmax values were 197.57±27.40 nmol·L-1 and 191.10±27.35 nmol·L-1, respectively; the AUC and Cmax values of reference medicine were 9.37±1.27 nmol·h·ml-1 and 169.48±22.83 nmol·L-1, respectively. The relative bioavailability of 50 μg levothyroxine sodium tables was 107.3%, while 100 μg was 109.9%, with a 95% confidence interval of 101.6%-113.3% and 104.1%-116.1% respectively. Conclusion: The study results indicated that the Radioimmunoassay methods applied in this study are appropriate and showed two domestic levothyroxine sodium preparations and Euthyrox 100 are bioequivalent

  19. BIOAVAILABILITY AND PHARMACOKINETICS OF ANASTROZOLE IN HEALTHY MALE VOLUNTEERS

    Institute of Scientific and Technical Information of China (English)

    安富荣; 崔岚; 刘晓琰; 王平全; 祝德秋; 曹惠明

    2002-01-01

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

  20. ENHANCEMENT OF BIOAVAILABILITY THROUGH INCREASE IN DRUG PERMEATION, STABILITY AND RETENTION TIME

    Directory of Open Access Journals (Sweden)

    Vishal Sachdeva

    2013-06-01

    Full Text Available The rate and extent to which an unchanged drug reaches the systemic circulation is called as bioavailability (BA. Bioavailability, a subcategory of absorption is one of the principal pharmacokinetic parameter determined for an active substance form a pharmaceutical product. It also indicates the fractional extent to which a dose of drug reaches its site of action or biological fluid from which the drug has access to its site of action. Physical properties of drug, drug formulation, route of administration, gastric emptying rate etc. are several factors affect the bioavailability of drug from its drug product. Poor solubility, enzymatic and transporters barrier, drug stability and short retention of the drug in stomach due to peristaltic movement are several factors decrease the bioavailability of the drug. This review deals with the bioavailability improvements techniques from poor permeation, lesser stability and short retention of the drug in stomach. Lipid based formulations; ion pairing and use of permeation enhancer are different methods to enhance the bioavailability through increase in permeation. Enteric coating, complexation and metabolism inhibitors lead to increase in drug stability. Bioadhesive polymers in formulation improve the gastro retention time serve as improved bioavailable product.

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

    International Nuclear Information System (INIS)

    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.

  2. 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.

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

    International Nuclear Information System (INIS)

    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-HClO4, EDTA, CaCl2, NH4NO3, NaNO3, 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 (r²adj = 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 (r²adj = 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 assessing

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

    International Nuclear Information System (INIS)

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

  5. Comparative pharmacokinetics and bioavailability of tapentadol following oral administration of immediate- and prolonged-release formulations

    NARCIS (Netherlands)

    Gohler, K.; Brett, M.; Smit, J.W.A.; Rengelshausen, J.; Terlinden, R.

    2013-01-01

    OBJECTIVE: To evaluate the bioavailability and pharmacokinetics of orally administered tapentadol immediate release (IR) compared with tapentadol prolonged release (PR). METHODS: Three randomized, open-label, crossover studies were conducted in subjects under fasted conditions. Studies 1 and 2 deter

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

    International Nuclear Information System (INIS)

    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)

  7. Bioavailability of water-soluble CoQ10 in beagle dogs.

    Science.gov (United States)

    Prosek, Mirko; Butinar, Janos; Lukanc, Barbara; Fir, Maja Milivojevic; Milivojevic, Luka; Krizman, Mitja; Smidovnik, Andrej

    2008-08-01

    The bioavailability of a novel water-soluble inclusion complex of CoQ10, prepared in our laboratory was determined and compared with the bioavailability of commercially available oil-based form of CoQ10. Experimental work consisted of single dose comparative bioavailability study on seven beagle dogs, with a 14-day washout period between treatments. Identification and quantification of CoQ10 was done with HPLC-MS method using positive APCI ionization and SIM mode, M+ m/z 863.4. The bioavailability results confirm that the water-soluble formulation has nearly three times higher AUC(0-48 h), two times higher Cmax, and Tmax is shortened from 6 to 4 h. PMID:18495407

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

    Science.gov (United States)

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

  9. 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.

  10. 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; Müllertz, Anette

    2005-01-01

    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...... intestine and protection against precipitation of seocalcitol in the gastro intestinal tract. There was no difference in the in vivo bioavailability of seocalcitol between the MCT and the LCT solutions, which correlates with the identical in vitro solubility of seocalcitol in SIM containing MC-LP or LC-LP....

  11. In Vivo Assessment of Arsenic Bioavailability in Rice and Its Significance for Human Health Risk Assessment

    OpenAIRE

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

    2006-01-01

    Background Millions of people worldwide consume arsenic-contaminated rice; however, little is known about the uptake and bioavailability of arsenic species after arsenic-contaminated rice ingestion. Objectives In this study, we assessed arsenic speciation in greenhouse-grown and supermarket-bought rice, and determined arsenic bioavailability in cooked rice using an in vivo swine model. Results In supermarket-bought rice, arsenic was present entirely in the inorganic form compared to greenhous...

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

    OpenAIRE

    Narala, Arjun; VEERABRAHMA, KISHAN

    2013-01-01

    Quetiapine fumarate is an antipsychotic drug with poor oral bioavailability (9%) due to first-pass metabolism. Present work is an attempt to improve oral bioavailability of quetiapine fumarate by incorporating in solid lipid nanoparticles (SLN). Six quetiapine fumarate SLN formulations were developed using three different lipids by hot homogenisation followed by ultrasonication. The drug excipient compatibility was studied by differential scanning calorimetry (DSC). Stable quetiapine fumarate...

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

    OpenAIRE

    Raynaud, Xavier; Jaillard, Benoit; Leadley, Paul

    2008-01-01

    Plants modify nutrient availability by releasing chemicals in 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 upt...

  14. 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...

  15. Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women

    OpenAIRE

    Sato Toshiro; Schurgers Leon J; Uenishi Kazuhiro

    2012-01-01

    Abstract Background Vitamin K2 contributes to bone and cardiovascular health. Therefore, two vitamin K2 homologues, menaquinone-4 (MK-4) and menaquinone-7 (MK-7), have been used as nutrients by the food industry and as nutritional supplements to support bone and cardiovascular health. However, little is known about the bioavailability of nutritional MK-4. To investigate MK-4 and MK-7 bioavailability, nutritional doses were administered to healthy Japanese women. Findings Single dose administr...

  16. 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...

  17. Bioavailability of Heme Iron in Biscuit Filling Using Piglets as an Animal Model for Humans

    OpenAIRE

    Adrián Guillermo Quintero-Gutiérrez, Guillermina González-Rosendo, Jonathan Sánchez-Muñoz, Javier Polo-Pozo, José Juan Rodríguez-Jerez

    2008-01-01

    The objective of this work was to evaluate the bioavailability of heme iron added to biscuit filling. It comprised two stages: first, the development of the heme iron enriched biscuit filling; second, the evaluation of the bioavailability of the mineral in fattening piglets. Two groups were selected randomly and fed: a) Low iron feed and biscuits with heme iron supplemented filling; b) Normal feed (with ferrous sulphate). Weight and blood parameters were measured every fifteen days. Averages ...

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

    OpenAIRE

    Olthof, M.R.

    2001-01-01

    Dietary antioxidants might prevent oxidative damage to tissues and therefore protect against cardiovascular disease and cancer. Dietary phenols are strong antioxidants in vitro but their role in vivo is uncertain. Furthermore, there are only limited data on their bioavailability in humans. The aim of this thesis was to investigate whether bioavailability data on flavonoids and cinnamic acids support the hypothesis that they can affect health in humans . Because the group of phenols in foods i...

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

    OpenAIRE

    Veldkamp, T; Diepen, van, F.N.J.; 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...

  20. Polymorph Impact on the Bioavailability and Stability of Poorly Soluble Drugs

    OpenAIRE

    Roberta Censi; Piera Di Martino

    2015-01-01

    Drugs with low water solubility are predisposed to poor and variable oral bioavailability and, therefore, to variability in clinical response, that might be overcome through an appropriate formulation of the drug. Polymorphs (anhydrous and solvate/hydrate forms) may resolve these bioavailability problems, but they can be a challenge to ensure physicochemical stability for the entire shelf life of the drug product. Since clinical failures of polymorph drugs have not been uncommon, and some of ...

  1. Potential bioavailability of particulate phosphorus in runoff from arable clayey soils

    OpenAIRE

    Uusitalo, Risto

    2004-01-01

    Runoff phosphorus (P) associated with eroded soil contributes to eutrophication to some extent. The present work examines two methods for estimating the potential bioavailability of particulate P (PP) in runoff, and studies the concentrations and losses of different P forms in surface and subsurface runoff from arable soils. The potential bioavailability of PP was approximated by extraction with (i) anion exchange resin (AER-PP), giving a measure of desorbable PP under aerobic conditions, and...

  2. Experimental determination of the oral bioavailability and bioaccessibility of lead particles

    OpenAIRE

    Deshommes Elise; Tardif Robert; Edwards Marc; Sauvé Sébastien; Prévost Michèle

    2012-01-01

    Abstract In vivo estimations of Pb particle bioavailability are costly and variable, because of the nature of animal assays. The most feasible alternative for increasing the number of investigations carried out on Pb particle bioavailability is in vitro testing. This testing method requires calibration using in vivo data on an adapted animal model, so that the results will be valid for childhood exposure assessment. Also, the test results must be reproducible within and between laboratories. ...

  3. Lower Zinc Bioavailability May Be Related to Higher Risk of Subclinical Atherosclerosis in Korean Adults

    OpenAIRE

    Su Kyoung Jung; Mi-Kyung Kim; Young-Hoon Lee; Dong Hoon Shin; Min-Ho Shin; Byung-Yeol Chun; Bo Youl Choi

    2013-01-01

    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 (MRCohor...

  4. In-vivo Self Emulsification: Tools for Bioavailability Enhancement

    Directory of Open Access Journals (Sweden)

    Shweta Mishra

    2015-03-01

    Full Text Available With the advancements in science and technology, a lot of new drug molecules have been added and are being added to our repertoire of drugs for fighting against diseases and ailments that trouble mankind. Each and every drug molecule is different in respect of their physico-chemical properties, thereby differing in their biotherapeutic effects. Problems like poor solubility and low permeability may render a perfectly effective drug molecule inactive in vivo because of low bioavailabilty. Thus the drug molecules which fall under the BCS category of Class II and Class IV represent certain specific problems regarding attainment of therapeutic drug concentrations at the required site and their bioavailability. Various techniques and drug delivery systems are being developed for such drugs. SEDDS or SELF’s represent one of such efforts. SEDDS are an isotropic mixture of one or more hydrophilic solvent and co- solvent /surfactants. On mild agitation they form fine oil – in- water (o/w microemulsion. This present study aims at studying the various formulation, classification, optimization and utilization aspects of these systems.

  5. 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.

  6. 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.

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

    International Nuclear Information System (INIS)

    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.

  8. Asymmetric dimethylarginine, endothelial nitric oxide bioavailability and mortality in sepsis.

    Directory of Open Access Journals (Sweden)

    Joshua S Davis

    Full Text Available BACKGROUND: Plasma concentrations of asymmetric dimethylarginine (ADMA, an endogenous inhibitor of nitric oxide synthase, are raised in patients with chronic vascular disease, causing increased cardiovascular risk and endothelial dysfunction, but the role of ADMA in acute inflammatory states is less well defined. METHODS AND RESULTS: In a prospective longitudinal study in 67 patients with acute sepsis and 31 controls, digital microvascular reactivity was measured by peripheral arterial tonometry and blood was collected at baseline and 2-4 days later. Plasma ADMA and L-arginine concentrations were determined by high performance liquid chromatography. Baseline plasma L-arginine: ADMA ratio was significantly lower in sepsis patients (median [IQR] 63 [45-103] than in hospital controls (143 [123-166], p<0.0001 and correlated with microvascular reactivity (r = 0.34, R(2 = 0.12, p = 0.02. Baseline plasma ADMA was independently associated with 28-day mortality (Odds ratio [95% CI] for death in those in the highest quartile (≥ 0.66 µmol/L = 20.8 [2.2-195.0], p = 0.008, and was independently correlated with severity of organ failure. Increase in ADMA over time correlated with increase in organ failure and decrease in microvascular reactivity. CONCLUSIONS: Impaired endothelial and microvascular function due to decreased endothelial NO bioavailability is a potential mechanism linking increased plasma ADMA with organ failure and death in sepsis.

  9. Selenium Biochemistry and Bioavailability: Implications for Animal Agriculture

    Directory of Open Access Journals (Sweden)

    Shaniko Shini

    2015-12-01

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

  10. Cadmium bioavailability and speciation using the permeation liquid membrane

    Energy Technology Data Exchange (ETDEWEB)

    Bayen, Stephane [CABE, University of Geneva, Sciences II, 30 Quai Ernest Ansermet, CH 1211, Geneva 4 (Switzerland)]. E-mail: stephane.bayen@cabe.unige.ch; Worms, Isabelle [CABE, University of Geneva, Sciences II, 30 Quai Ernest Ansermet, CH 1211, Geneva 4 (Switzerland); Parthasarathy, Nalini [CABE, University of Geneva, Sciences II, 30 Quai Ernest Ansermet, CH 1211, Geneva 4 (Switzerland); Wilkinson, Kevin [Department of Chemistry, University of Montreal, CP 6128, succ. Centre-Ville, Montreal, QC H3C 3J7 (Canada); Buffle, Jacques [CABE, University of Geneva, Sciences II, 30 Quai Ernest Ansermet, CH 1211, Geneva 4 (Switzerland)

    2006-08-11

    The permeation liquid membrane (PLM) technique was used to evaluate cadmium speciation in media resembling natural freshwaters. A planar sheet PLM system was characterized by measuring Cd fluxes in the absence and presence of complexing agents such as citrate, malonate, nitrilotriacetate and the Suwannee River standard humic acid. Comparison with theoretical speciation calculations and the results of a Cd{sup 2+} selective electrode, showed that free Cd was correctly measured using the planar sheet PLM within the studied concentration range, i.e. 10{sup -8} to 10{sup -4} M. The effect of pH and potentially co-transported ions on Cd transport through the PLM was also studied. An example of the ability of the hollow-fiber PLM (HFPLM) to measure free Cd in the nM range is also presented. In order to evaluate the usefulness of the technique as a predictor of bioavailability, Cd PLM measurements (fluxes) were compared to Cd biouptake (internalization flux) for a freshwater alga, Chlorella kesslerii, in the absence and presence of SRHA. The use of PLM measurements is shown to be an attractive tool to better understand Cd biouptake.

  11. 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.

  12. Gastro retentive microencapsulated Cefpodoxime Proxetil to improve oral bioavailability

    Institute of Scientific and Technical Information of China (English)

    Deepa Karthikeyan; Karthikeyan M

    2009-01-01

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

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

    International Nuclear Information System (INIS)

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

  14. 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.

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

    DEFF Research Database (Denmark)

    Bredsdorff, Lea

    Dietary flavonoids constitute an important group of potential health protective compounds from fruits, vegetables, and plant-based products such as tea and wine. The beneficial effects of a diet high in flavonoids on the risk of coronary heart disease (CHD) have been shown in several epidemiologi......Dietary flavonoids constitute an important group of potential health protective compounds from fruits, vegetables, and plant-based products such as tea and wine. The beneficial effects of a diet high in flavonoids on the risk of coronary heart disease (CHD) have been shown in several...... activity. The present thesis was initiated with two objectives. One objective was to investigate the bioavailability and metabolism of the dietary important flavonoids hesperetin and naringenin from commercial, hesperidin-fortified, and enzymatically treated orange juice. The other objective was to explore...... orange juice: commercial orange juice with a natural concentration of hesperetin and naringenin rhamnoglucosides, 3-times hesperidin (hesperetin-7-O-rhamnoglucoside) fortified orange juice and orange juice enzymatically treated to yield hesperetin and naringenin-7-O-glucosides. The effect of enzymatic...

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

    International Nuclear Information System (INIS)

    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

  17. Biosolids inhibit bioavailability and plant uptake of triclosan and triclocarban.

    Science.gov (United States)

    Fu, Qiuguo; Wu, Xiaoqin; Ye, Qingfu; Ernst, Fredrick; Gan, Jay

    2016-10-01

    Biosolids from wastewater treatment are primarily disposed of via land applications, where numerous pharmaceuticals and personal care products (PPCPs) may contaminate food crops and pose a human exposure risk. Biosolids are rich in organic carbon and addition of biosolids can increase the sorption of certain PPCPs in soil, decreasing their bioavailability. This study tested the hypothesis that the relative plant uptake of PPCPs decreases with increasing biosolids amendment. Accumulation of triclosan and triclocarban was measured in roots of radish and carrot grown in soils with or without biosolids. Addition of biosolids significantly prolonged the persistence of triclosan in soil. When expressed in bioaccumulation factor (BCF), accumulation of triclosan drastically decreased in biosolids-amended soils, while the effect was limited for triclocarban. Compared to the unamended soil, amending biosolids at 2% (w/w) decreased BCF of triclosan in the edible tissues of radish and carrot by 85.4 and 89.3%, respectively. Measurement using a thin-film passive sampler provided direct evidence showing that the availability of triclosan greatly decreased in biosolids-amended soils. Partial correlation analysis using data from this and published studies validated that biosolids decreased plant uptake primarily by increasing soil organic carbon content and subsequently sorption. Therefore, contamination of food crops by biosolids-borne contaminants does not linearly depend on biosolids use rates. This finding bears significant implications in the overall risk evaluation of biosolids-borne contaminants. PMID:27337347

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

    Science.gov (United States)

    Amézqueta, Susana; Torres, Josep Lluís

    2016-05-01

    Iminocyclitols are chemically and metabolically stable, naturally occurring sugar mimetics. Their biological activities make them interesting and extremely promising as both drug leads and functional food ingredients. The first iminocyclitols were discovered using preparative isolation and purification methods followed by chemical characterization using nuclear magnetic resonance spectroscopy. In addition to this classical approach, gas and liquid chromatography coupled to mass spectrometry are increasingly used; they are highly sensitive techniques capable of detecting minute amounts of analytes in a broad spectrum of sources after only minimal sample preparation. These techniques have been applied to identify new iminocyclitols in plants, microorganisms and synthetic mixtures. The separation of iminocyclitol mixtures by chromatography is particularly difficult however, as the most commonly used matrices have very low selectivity for these highly hydrophilic structurally similar molecules. This review critically summarizes recent advances in the analysis of iminocyclitols from plant sources and findings regarding their quantification in dietary supplements and foodstuffs, as well as in biological fluids and organs, from bioavailability studies. PMID:26946023

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

    International Nuclear Information System (INIS)

    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

  20. 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.

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

    International Nuclear Information System (INIS)

    Stable isotope 111Cd 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.

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

    International Nuclear Information System (INIS)

    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 (CaCl2, NH4NO3, EDTA, HOAc) and correlation analysis of thorium uptake by wheat plant and extractable thorium, a mixture of 0.02 M EDTA + 0.5 M NH4OAc (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. Relating metal bioavailability to risk assessment for aquatic species: Daliao River watershed, China

    International Nuclear Information System (INIS)

    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

  4. 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. PMID:26808908

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

    Science.gov (United States)

    Wu, Xiang; Zhu, Lizhong

    2016-08-01

    Under current retrospective risk assessment framework, the total concentrations of organic pollutants in soils have been employed as the standard for over 30 years. The total concentrations reflect the overall accumulation in soils but tend to be overly conservative for assessing the ecological risks, where the bioavailability plays an important role. In this study, the bioavailability of organic pollutants in soils was evaluated using a stepwise and tiered classification method, namely the sequential ultrasonic extraction procedure (SEUP). The water-soluble and acid-soluble fractions extracted by the SEUP were the bioavailable fractions. The reliability and environmental relevance of the speciation method were examined with representative organic pollutants using the root uptake methods and the semipermeable membrane devices (SPMDs). The plant uptake amounts corrected with weight were highly correlated with the bioavailable fractions (R(2) > 0.75). The amounts of the bioavailable fractions were negatively correlated with the logKow values (R(2) ranging from 0.71 to 0.77) of the organic pollutants and the contents of soil organic matter (R(2) ranging from 0.68 to 0.96). As a refinement of the current risk assessment framework, the SUEP that has proved to be a reliable and convenient is thus highly recommended for evaluating the bioavailability of organic pollutants in soils. PMID:27156212

  6. 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. PMID:27002282

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

    International Nuclear Information System (INIS)

    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.

  8. Predicting arsenic relative bioavailability in contaminated soils using meta analysis and relative bioavailability-bioaccessibility regression models.

    Science.gov (United States)

    Juhasz, Albert L; Weber, John; Smith, Euan

    2011-12-15

    A number of in vitro assays are available for the determination of arsenic (As) bioaccessibility and prediction of As relative bioavailability (RBA) to quantify exposure for site-specific risk assessment. These data are usually considered in isolation; however, meta analysis may provide predictive capabilities for source-specific As bioaccessibility and RBA. The objectives of this study were to predict As RBA using previously published in vivo/in vitro correlations and to assess the influence of As sources on As RBA independent of geographical location. Data representing 351 soils (classified based on As source) and 514 independent bioaccessibility values were retrieved from the literature for comparison. Arsenic RBA was predicted using published in vivo/in vitro regression models, and 90th and 95th percentiles were determined for each As source classification and in vitro methodology. Differences in predicted mean As RBA were observed among soils contaminated from different As sources and within source materials when various in vitro methodologies were utilized. However, when in vitro data were standardized by transforming SBRC intestinal, IVG, and PBET data to SBRC gastric phase values (through linear regression models), predicted As RBA values for As sources followed the order CCA posts ≥ herbicide/pesticide > mining/smelting > gossan soils with 95th percentiles for predicted As RBA of 78.0, 78.4, 67.0, and 23.7%, respectively. PMID:22059522

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

    International Nuclear Information System (INIS)

    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

  10. 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

  11. Bioavailability enhanced rhizosphere remediation of petroleum hydrocarbon contaminated soil

    International Nuclear Information System (INIS)

    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

  12. 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

  13. 226Ra bioavailability of plants at urgeirica uranium mill tailings

    International Nuclear Information System (INIS)

    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 226Ra 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 226Ra 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 226Ra uptake by plants show that 226Ra concentration ratios for eucalyptus and pines decrease at low 226Ra concentration in the solid wastes and appear relatively constant at higher radium concentrations. For shrubs, the concentration ratios increase at higher 226Ra 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 226Ra 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 226Ra concentration ratios were obtained when calculated on the basis of available radium than when total radium was considered, for all the dams. (author)

  14. 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)

  15. Novel micelle formulations to increase cutaneous bioavailability of azole antifungals.

    Science.gov (United States)

    Bachhav, Y G; Mondon, K; Kalia, Y N; Gurny, R; Möller, M

    2011-07-30

    Efficient topical drug administration for the treatment of superficial fungal infections would deliver the therapeutic agent to the target compartment and reduce the risk of systemic side effects. However, the physicochemical properties of the commonly used azole antifungals make their formulation a considerable challenge. The objective of the present investigation was to develop aqueous micelle solutions of clotrimazole (CLZ), econazole nitrate (ECZ) and fluconazole (FLZ) using novel amphiphilic methoxy-poly(ethylene glycol)-hexyl substituted polylactide (MPEG-hexPLA) block copolymers. The CLZ, ECZ and FLZ formulations were characterized with respect to drug loading and micelle size. The optimal drug formulation was selected for skin transport studies that were performed using full thickness porcine and human skin. Penetration pathways and micellar distribution in the skin were visualized using fluorescein loaded micelles and confocal laser scanning microscopy. The hydrodynamic diameters of the azole loaded micelles were between 70 and 165nm and the corresponding number weighted diameters (d(n)) were 30 to 40nm. Somewhat surprisingly, the lowest loading efficiency (13-fold higher than that from Pevaryl® cream (22.8±3.8 and 1.7±0.6μg/cm(2), respectively). A significant enhancement was also observed with human skin; the amounts of ECZ deposited were 11.3±1.6 and 1.5±0.4μg/cm(2), respectively (i.e., a 7.5-fold improvement in delivery). Confocal laser scanning microscopy images supported the hypothesis that the higher delivery observed in porcine skin was due to a larger contribution of the follicular penetration pathway. In conclusion, the significant increase in ECZ skin deposition achieved using the MPEG-dihexPLA micelles demonstrates their ability to improve cutaneous drug bioavailability; this may translate into improved clinical efficacy in vivo. Moreover, these micelle systems may also enable targeting of the hair follicle and this will be investigated

  16. 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.

  17. 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. PMID:25841357

  18. Formulation optimization of Docetaxel loaded self-emulsifying drug delivery system to enhance bioavailability and anti-tumor activity

    OpenAIRE

    Valicherla, Guru R.; Dave, Kandarp M.; Anees A. Syed; Mohammed Riyazuddin; Gupta, Anand P.; Akhilesh Singh; Wahajuddin,; Kalyan Mitra; Dipak Datta; Gayen, Jiaur R.

    2016-01-01

    Poor bioavailability of Docetaxel (DCT) arising due to its low aqueous solubility and permeability limits its clinical utility. The aim of the present study was to develop DCT loaded self-emulsified drug delivery systems (D-SEDDS) and evaluate its potential ability to improve the oral bioavailability and therapeutic efficacy of DCT. D-SEDDS were characterized for their in vitro antitumor activity, in situ single pass intestinal perfusion (SPIP), bioavailability, chylomicron flow blocking stud...

  19. 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...

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

    Science.gov (United States)

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

    2015-05-01

    The aim of this study was to load amorphous hydrophobic drug into ordered mesoporous silica (SBA-15) by supercritical carbon dioxide technology in order to improve the dissolution and bioavailability of the drug. Asarone was selected as a model drug due to its lipophilic character and poor bioavailability. In vitro dissolution and in vivo bioavailability of the obtained Asarone-SBA-15 were significantly improved as compared to the micronized crystalline drug. This study offers an effective, safe, and environmentally benign means of solving the problems relating to the solubility and bioavailability of hydrophobic molecules. PMID:25720818

  1. Comparison of in vivo and in vitro methodologies for the assessment of arsenic bioavailability in contaminated soils.

    Science.gov (United States)

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

    2007-10-01

    An in vivo swine assay was utilised for the determination of arsenic (As) bioavailability in contaminated soils. Arsenic bioavailability was assessed using pharmacokinetic analysis encompassing area under the blood plasma-As concentration time curve following zero correction and dose normalisation. In contaminated soil studies, As uptake into systemic circulation was compared to an arsenate oral dose and expressed as relative As bioavailability. Arsenic bioavailability ranged from 6.9+/-5.0% to 74.7+/-11.2% in 12 contaminated soils collected from former railway corridors, dip sites, mine sites and naturally elevated gossan soils. Arsenic bioavailability was generally low in the gossan soils and highest in the railway soils, ranging from 12.1+/-8.5% to 16.4+/-9.1% and 11.2+/-4.7% to 74.7+/-11.2%, respectively. Comparison of in vivo and in vitro (Simplified Bioaccessibility Extraction Test [SBET]) data from the 12 contaminated soils and bioavailability data collected from an As spiked soil study demonstrated that As bioavailability and As bioaccessibility were linearly correlated (in vivo As bioavailability (mgkg(-1))=14.19+0.93.SBET As bioaccessibility (mgkg(-1)); r(2)=0.92). The correlation between the two methods indicates that As bioavailability (in vivo) may be estimated using the less expensive, rapid in vitro chemical extraction method (SBET) to predict As exposure in human health risk assessment. PMID:17585998

  2. Phospholipid-based solid drug formulations for oral bioavailability enhancement: A meta-analysis.

    Science.gov (United States)

    Fong, Sophia Yui Kau; Brandl, Martin; Bauer-Brandl, Annette

    2015-12-01

    Low bioavailability nowadays often represents a challenge in oral dosage form development. Solid formulations composed of drug and phospholipid (PL), which, upon contact with water, eventually form multilamellar liposomes (i.e. 'proliposomes'), are an emerging approach to solve such issue. Regarded as an 'improved' version of liposomes concerning storage stability, the potential and versatility of a range of such formulations for oral drug delivery have been extensively discussed. However, a systematic and quantitative analysis of the studies that applied solid PL for oral bioavailability enhancement is currently lacking. Such analysis is necessary for providing an overview of the research progress and addressing the question on how promising this approach can be on bioavailability enhancement. The current review performed a systematic search of references in three evidence-based English databases, Medline, Embase, and SciFinder, from the year of 1985 up till March 2015. A total of 112 research articles and 82 patents that involved solid PL-based formulations were identified. The majority of such formulations was intended for oral drug delivery (55%) and was developed to address low bioavailability issues (49%). A final of 54 studies that applied such formulations for bioavailability enhancement of 43 different drugs with poor water solubility and/or permeability were identified. These proof-of-concept studies with in vitro (n=31) and/or animal (n=23) evidences have been systematically summarized. Meta-analyses were conducted to measure the overall enhancement power (percent increase compared to control group) of solid PL formulations on drugs' solubility, permeability and oral bioavailability, which were found to be 127.4% (95% CI [86.1, 168.7]), 59.6% (95% CI [30.1, 89.0]), and 18.5% (95% CI [10.1, 26.9]) respectively. Correlations between the enhancement factors and in silico physiochemical properties of drugs were also performed to check if such approach can be

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

    Directory of Open Access Journals (Sweden)

    Lin LC

    2012-06-01

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

  4. 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.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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)

  7. 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.

  8. 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. PMID:27080888

  9. Rationale of using Vinca minor Linne dry extract phytocomplex as a vincamine's oral bioavailability enhancer.

    Science.gov (United States)

    Hasa, Dritan; Perissutti, Beatrice; Dall'Acqua, Stefano; Chierotti, Michele R; Gobetto, Roberto; Grabnar, Iztok; Cepek, Cinzia; Voinovich, Dario

    2013-05-01

    Vincamine is a poorly soluble potent neuroprotector and cerebral vasodilator, used for the treatment for CNS disorders. In some cases, the bioavailability of pure compounds is strongly influenced by the co-administration of other constituents, and in some cases, the so called 'phytocomplex' may act as enhancer of absorption of selected phytochemicals. In this paper, the oral bioavailability of vincamine when administered as a standardised Vinca minor L. leaf dry extract rather than pure indole alkaloid is demonstrated to be higher. The chosen alkaloid-enriched and standardised dry extract was widely characterised by means of HPLC-MS, PXRD, DSC, XPS, (13)C and (15)N solid-state NMR (SSNMR) using pure vincamine as a matter of comparison. Then, the in vitro dissolution performances of the two products and their in vivo bioavailability in rats were evaluated. The sevenfold improvement in oral bioavailability of the dry extract with respect to the pure vincamine was ascribed to interactions between the indole alkaloid and the corollary of ingredients of the dry extract, giving rise to the protonation of the alkaloid vincamine, thus enhancing its dissolution in physiological fluids. Present data demonstrate that alkaloid vincamine administered as a whole plant extract has a higher bioavailability compared to the pure chemical compound. PMID:23238273

  10. Lacidipine self-nanoemulsifying drug delivery system for the enhancement of oral bioavailability.

    Science.gov (United States)

    Subramanian, Natesan; Sharavanan, Shanmugam Palaniappan; Chandrasekar, Ponnusamy; Balakumar, Alagar; Moulik, Satya Priya

    2016-04-01

    Low bioavailability of Lacidipine (LD), an calcium channel blocker pose many challenges in the treatment of hypertension. The objective of this study was to formulate and characterize LD self-nanoemulsifying drug delivery systems (SNEDDS) to improve oral bioavailability of the drug. Formulations were evaluated for globule size, surface morphology, emulsification time, cloud point, drug content, in vitro dissolution, ex vivo permeation, stability and oral bioavailability studies. Captex 810D, TPGS, Tween-60, Transcutol P and PEG 400 was selected based on the solubility study results. The optimized SNEDDS readily gets nanoemulsified at 37 °C with droplet size of 41 nm when mixed with 200 times of its water. Transmission electron microscope photographs confirmed the spherical shape of the globules. In vitro dissolution of SNEDDS showed more than 80 % of drug release within 15 min. The ex vivo permeation of LD from SNEDDS is 4.8- and 9-fold higher compared to pure drug in the absence and presence of verapamil respectively. The stability study of the SNEDDS confirmed no environmental effect on the physical nature and drug content. Oral bioavailability of SNEDDS is 2.5 times higher than marketed tablet. The results suggest that, the SNEDDS formulation can be used as a possible alternative for the traditional oral formulations of LD to improve its oral bioavailability. PMID:26362165

  11. Mercury mobility and bioavailability in soil from contaminated area

    Science.gov (United States)

    Boszke, Leonard; Kowalski, Artur; Astel, Aleksander; Barański, Andrzej; Gworek, Barbara; Siepak, Jerzy

    2008-09-01

    The mobility and bioavailability of mercury in the soil from the area near a plant using elemental mercury for manufacturing thermometers, areometers, glass energy switches and other articles made of technical glass has been evaluated. Mercury has been determined by sequential extraction method and with additional thermo desorption stage to determine elemental mercury. The procedure of sequential extraction involves five subsequent stages performed with the solutions of chloroform, deionized water, 0.5 M HCl, 0.2 M NaOH and aqua regia. The mean concentration of total mercury in soil was 147 ± 107 μg g-1 dry mass (range 62-393), and the fractionation revealed that mercury was mainly bound to sulfides 56 ± 8% (range 45-66), one of the most biounavailable and immobile species of mercury in the environment. The fractions that brought lower contribution to the total mercury content were semi-mobile humic matter 22 ± 9% (range 11-34) and elemental mercury 17 ± 5% (range 8-23). The contributions brought by the highly mobile and toxic organomercury compounds were still lower 2.3 ± 2.7% (range 0.01-6.5). The lowest contributions brought the acid-soluble mercury 1.5 ± 1.3% (range 0.1-3.5) and water-soluble mercury 1.0 ± 0.3% (range 0.6-1.7). The surface layer of soil (0-20 cm) was characterized by higher mercury concentrations than that of the subsurface soil (60-80 cm), but the fractional contributions were comparable. The comparison of mercury fractionation results obtained in this study for highly polluted soils with results of fractionation of uncontaminated or moderately contaminated samples of soil and sediments had not shown significant statistical differences; however, in the last samples elemental mercury is usually present at very low concentrations. On the basis of obtained correlation coefficients it seems that elemental mercury soils from “Areometer” plant are contaminated; the main transformation is its vaporization to atmosphere and oxidation to

  12. 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 grou...... 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.......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...

  13. ENHANCEMENT OF ORAL BIOAVAILABILITY OF LIPOPHILLIC DRUGS FROMSELF-MICROEMULSIFYING DRUG DELIVERY SYSTEM (SMEDDS

    Directory of Open Access Journals (Sweden)

    GUPTA ROOP N1, GUPTA RAKESH AND RATHORE GARVENDRA SINGH*

    2009-12-01

    Full Text Available Approximately 40 per cent of new drug candidates have poor water solubility and the oral delivery of such drugs isfrequently associated with implications of low bioavailability, high intra and inter-subject variability, and lack of doseproportionality. Bioavailability problem of lipophillic drugs can be solved by formation of Self-Micro Emulsifying DrugDelivery System (SMEDDS. SMEDDS appears to be a unique and industrially feasible approach to overcome theproblem of low oral bioavailability associated with the lipophillic drugs. Self-micro emulsifying formulations are mixturesof oils and surfactants, ideally isotropic, and sometimes containing co-solvents, which emulsify spontaneously to producefine oil-in-water emulsion when introduced into aqueous phase under conditions of gentle agitation. The digestive motilityof the stomach and intestine provide the agitation necessary for self-emulsification in vivo. This review describesSMEDDS as one of the important approaches to overcome the formulation difficulties of potent lipophillic drugs.

  14. Measurement of iron bioavailability by means of stable 54Fe and mass spectrometry

    International Nuclear Information System (INIS)

    A procedure is described to evaluate the bioavailability of iron in pharmaceutical preparations by means of 54Fe as a tracer and mass spectrometry for the determination of time dependent changes in the isotope ratio of 54Fe/56Fe in red blood cells. Iron tablets with an increased portion of 54Fe were administered to iron deficient subjects and red cell iron utilization was used as a measure of iron bioavailability. Iron utilization was derived from changes in the 54Fe/56Fe ratio as evaluated by means of fast atom bombardment-mass spectrometry (FAB-MS) on processed blood samples. A good intraindividual reproducibility was observed for blood samples drawn at various times after application of the trial drug. Figures for bioavailability and its interindividual variations were in the range expected from comparable studies on similar iron preparations using radioiron as tracers. (author)

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

    DEFF Research Database (Denmark)

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

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

  16. Development and characterization of solid lipid nanoparticles for enhancement of oral bioavailability of Raloxifene

    Directory of Open Access Journals (Sweden)

    B Divyakant Patel

    2012-01-01

    Full Text Available The objective of this study was to increase the oral bioavailability of Raloxifene having an absolute bioavailability only 2% due to extensive first pass hepatic metabolism by incorporating it in Solid Lipid Nanoparticles (SLNs. The optimized RSLNs prepared by Ultrasonic Emulsification and Low Temperature Solidification method showed the mean particle size, zeta potential and percentage drug entrapment of 101.4±3.5 nm, 19.4±0.279 mv, 97.67±1.02% respectively. The in-vitro intestinal permeability study indicated significantly higher permeation of the RSLNs than the marketed preparation. The in-vivo studies showed that pharmacokinetic parameters for the RSLNs were 3.5 times higher than the marketed preparation indicating significant increase in the oral bioavailability of the Raloxifene.

  17. 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...... 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 and......). 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...

  18. Ageing of atrazine in manure amended soils assessed by bioavailability to Pseudomonas sp. strain ADP

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Bælum, Jacob; Strobel, Bjarne W.;

    2014-01-01

    Animal manure is applied to agricultural land in areas of high livestock production. In the present study, we evaluated ageing of atrazine in two topsoils with and without addition of manure and in one subsoil. Ageing was assessed as the bioavailability of atrazine to the atrazine mineralizing...... bacteria Pseudomonas sp. strain ADP. Throughout an ageing period of 90 days bioavailability was investigated at days 1, 10, 32, 60 and 90, where ~108 cells g−1 of the ADP strain was inoculated to the 14C-atrazine exposed soil and 14CO2 was collected over 7 days as a measure of mineralized atrazine. Even...... though the bioavailable residue decreased in all of the three soils as time proceeded, we found that ageing occurred faster in the topsoils rich in organic carbon than in subsoil. For one topsoil rich in organic carbon content, Simmelkær, we observed a higher degree of ageing when treated with manure...

  19. Effects of Water Stress on Rice Production: Bioavailability of Potassium in Soil

    Directory of Open Access Journals (Sweden)

    Jahan, Sarwar

    2013-04-01

    Full Text Available Water demand in agriculture, municipal, and industrial purposes is increasing rapidly which will pressure on future demand in agriculture. To justify less water use in rice production, we produced rice under different water levels (DWLs and justified potassium bioavailability. There were five DWLs were employed in this experiment. Besides measuring yield and yield parameters, relative water content (WRC and chlorophyll content in leaves, soil pH and bioavailability of potassium (K in soil solution were measured. Yield and yield parameters showed insignificant difference under DWLs. Different water levels did not affect weekly data of chlorophyll content and RWC in leaves. But chlorophyll content and RWC in leaves were significantly higher in week 6 or 9 than week 3. Different water levels did not affect soil pH. Our results suggested that rice can be produced under low water input without affecting yield and yield parameters and K bioavailability in soil.

  20. Bioavailability and Pharmacodynamics of Promethazine on Long Duration Missions to the International Space Station

    Science.gov (United States)

    Putcha, Lakshmi; Boyd, Jason L.; Cintron, Nitza; Berens, Kurt L.

    2004-01-01

    Space motion sickness (SMS) is often treated in space with promethazine (PMZ). Common side effects of PMZ administration (50 mg intramuscular) on the ground are drowsiness and impaired cognitive performance. Anecdotal reports indicate that these effects are absent or less pronounced in space. This suggests that the availability of PMZ to the body (bioavailability) and/or the response of the body to PMZ (pharmacodynamics) may change during space flight. Opportunities for clinical research in space are limited. The study described here is our response to a NASA Research Announcement for proposals for flight-based research needed to improve, or answer specific questions about, diagnosis and therapy during space flight, and post-flight rehabilitation. We propose here to evaluate noninvasive methods for determining the bioavailability and pharmacodynamics of PMZ. The specific objectives of the proposed research are to 1) compare pharmacokinetic and pharmacodynamic parameters of PMZ, estimated from saliva and plasma levels after administration of PMZ, 2) estimate the relative bioavailability of the three dosage forms of PMZ that are often administered to control motion sickness symptoms in space, and 3) establish the dose-response relationship of PMZ. We will estimate the bioavailability of an intramuscular injection (IM), oral tablet, and rectal suppository of PMZ in noma1 subjects during ambulatory and antiorthostatic bed rest (ABR) conditions using novel stable isotope techniques. We will compare and contrast the bioavailability of PMZ during normal and microgravity conditions to examine changes in drug absorption and bioavailability during microgravit. Results of this study will validate methods for an approved in-flight investigation with this medication awaiting an opportunity for manifestation..

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

    Science.gov (United States)

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

    2016-04-01

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

  2. Influence of organic matter transformations on the bioavailability of heavy metals in a sludge based compost.

    Science.gov (United States)

    Ingelmo, Florencio; Molina, Maria José; Soriano, Maria Desamparados; Gallardo, Antonio; Lapeña, Leonor

    2012-03-01

    The agricultural use of anaerobically digested sewage sludge (ADSS) as stable, mature compost implies knowing its total content in heavy metals and their bioavailability. This depends not only on the initial characteristics of the composted substrates but also on the organic matter transformations during composting which may influence the chemical form of the metals and their bioavailability. 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. A detailed sampling at 0, 14, 84, and 140 days of the composting process was performed to measure C contents in humic acids (HAs), fulvic acids, (FAs) and humin, the total content of Zn, Pb, Cu, Ni, and Cd, and also their distribution into mobile and mobilisable (MB), and low bioavailability (LB) forms. Significant changes of C contents in HA, FA, and Humin, and in the FA/HA, HA/Humin and C(humus)/TOC ratios were observed during composting. The MB and LB fractions of each metal also varied significantly during composting. The MB fraction increased for Zn, Cu, Ni, and Cd, and the LB fraction increased for Pb. Stepwise linear regressions and quadratic curve estimation conducted on the MB and LB fractions of each metal as dependent on the measured organic variables suggested that Zn bioavailability was mainly associated to percentage of C in FAs. Bioavailability of Cu, Ni and Cd during composting was associated to humin and HAs. Pb concentration increased in the LB form, and its variations followed a quadratic function with the C(humus)/TOC ratio. Our results suggest that the composting process renders the metals in more available forms. The main forms of metal binding in the sludge and their availability in the final compost may be better described when metal fractionation obtained in sequential extraction and humus fractionation during composting are considered together. PMID:21570172

  3. 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

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

    Science.gov (United States)

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

    2016-03-01

    The aim was to determine the relative bioavailability of phosphorus (P) in peas for 21-day old broiler chickens using slope-ratio assay. One hundred and sixty eight male Ross 308 broiler chicks were divided into 42 groups 4 balanced for body weight and fed 7 diets in a completely randomized design (6 groups/diet) from day 1 to 21 of age. The diets were a corn-soybean meal basal diet, and the corn-soybean meal basal diet to which monosodium phosphate, brown- or yellow-seeded pea was added at the expense of cornstarch to supply 0.5% or 1% total phosphorus. Monosodium phosphate was included as a reference, and hence the estimated bioavailability of P in pea cultivars was relative to that in the monosodium phosphate. Birds and feed were weighed weekly and on d 21 they were killed to obtain tibia. The brown-seeded pea contained 23.4% crude protein, 0.47% P, whereas the yellow-seeded pea contained 24.3% crude protein and 0.38% P. Increasing dietary P supply improved (pyellow-seeded peas obtained using final body weight, average daily gain, tibia ash, and bone mineral density were 31.5% and 36.2%, 35.6% and 37.3%, 23.0% and 5.60%, and 40.3% and 30.3%, respectively. The estimated relative bioavailability of p values for brown- and yellow-seeded peas did not differ within each of the response criteria measured in this study. In conclusion, the relative bioavailability of P in pea did not differ depending on the cultivar (brown- vs yellow-seed). However, the relative bioavailability of P in pea may vary depending on the response criterion used to measure the bioavailability. PMID:26950872

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

    Directory of Open Access Journals (Sweden)

    Yanyan Wei

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

  6. 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.

  7. Effect of pomegranate pretreatment on the oral bioavailability of buspirone in male albino rabbits

    OpenAIRE

    M. Sarangapani; Y Madhusudan Rao; R Shiva Kumar; Ramesh, G.; Y Vamshi Vishnu; Bhargavi Latha, A.; Adukondalu, D.; Y Shravan Kumar

    2011-01-01

    Background and the Purpose of the study: Many drug substances and variety of naturally occurring dietary or herbal components are capable of interaction with the CYP enzyme system. The aim of the study was to investigate the effect of pomegranate juice pretreatment on the bioavailability of buspirone in rabbits. Methods: White New Zealand rabbits weighing 2.1±0.13 Kg were selected for study. The bioavailability of buspirone after pre-treatment with pomegranate juice (10 ml Kg-1 for sev...

  8. Time and moisture effects on total and bioavailable copper in soil water extracts

    DEFF Research Database (Denmark)

    Tom-Petersen, Andreas; Hansen, H.C.B.; Nybroe, O.

    2004-01-01

    between total metal content and metal toxicity calls for integrated chemical and biological analysis. The aim of this work was to determine time- and moisture-dependent changes in total water-extractable Cu as well as bioavailable Cu in soil water extracts. Measurements of total water-extractable copper...... ([Cu](tot)) were performed using furnace atomic absorption spectrometry. An in vitro assay employing a Cu-specific Pseudomonas fluorescens reporter strain was used to estimate Cu that was biologically available to the reporter strain. We refer to this copper fraction as "bioavailable," [Cu](bio). We...

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

    Directory of Open Access Journals (Sweden)

    Prakash Khadka

    2014-12-01

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

  10. Effect of adhesive matrix composition and terpinolene on indomethacin bioavailability in rats from transdermal therapeutic system.

    Science.gov (United States)

    Cal, Krzysztof; Sznitowska, Malgorzata; Janicki, Stanislaw

    2008-10-01

    Drug-in-adhesive matrix-type transdermal therapeutic systems for indomethacin (IND) were formulated and evaluated. Silicone and two types of polyacrylates were used as the bases of matrices. Terpinolene was used as a penetration enhancer. The physicochemical properties of matrices were determined. The bioavailability study of IND was performed in rats. The presence of IND in blood was demonstrated for each system. The calculated pharmacokinetics parameters for IND mainly depend on the solubility of IND in the adhesive layer. The positive influence of a penetration enhancer on IND bioavailability was observed only for one type of polyacrylate matrices. PMID:18777239

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

    Directory of Open Access Journals (Sweden)

    Olesja Bondarenko

    2008-11-01

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

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

    Science.gov (United States)

    García-Rodriguez, J J; Torrado, J; Bolás, F

    2001-06-01

    The bioavailability and anthelmintic activity of albendazole-cyclodextrin complexes (ABZ-CDC) compared to albendazole suspensions in carboxymethylcellulose (ABZ-CMC) was assessed in a mouse model for Trichinella infections. Swiss CD-1 mice experimentally infected with T. spiralis were treated with both formulations against enteral (adult worms) and parenteral (migrating and encysted larvae). Oral bioavailability was assessed in age matched mice treated with 50 mg/kg of both formulations. The anthelmintic effects and plasma concentration of the active metabolite albendazole-sulphoxide (ABZSO) enantiomer (-) were significantly increased following administration of ABZ-CDC in relation to ABZ-CMC. PMID:11484352

  13. Radiolabeled iron in soybeans: intrinsic labeling and bioavailability of iron to rats from defatted flour

    International Nuclear Information System (INIS)

    Soybeans can be efficiently labeled with radiolabeled iron by supplying the iron via a nutrient culture medium as an iron salt or as a chelate. By using dual labeled iron and EDTA, it was determined that none of the chelator was transported to the shoots with the iron. Therefore, the use of chelated iron as the iron source in the nutrient medium should not affect assessments of bioavailability of iron from plants. Bioavailability (determined from whole-body retention curves of 59Fe in rats) of iron from defatted soy flour was relatively high and addition of vitamin C did not significantly enhance absorption of iron from defatted soy flour

  14. 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...

  15. Assessment of Iron Bioavailability in Humans Using Stable Iron Isotope Techniques

    International Nuclear Information System (INIS)

    This publication on the assessment of iron bioavailability was developed as part of the IAEA's continuing efforts to transfer knowledge and technology in the use of stable isotope techniques in nutrition. It provides information on the theoretical background and practical application of state of the art methodology to measure human iron absorption and dietary iron bioavailability using stable (non-radioactive) isotopes. These techniques can be used to guide fortification and food based strategies to combat iron deficiency, which remains unacceptably high among infants, children and women of childbearing age in developing countries.

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

    Directory of Open Access Journals (Sweden)

    García-Rodriguez J.J.

    2001-06-01

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

  17. Heavy metals in soils from Baia Mare mining impacted area (Romania) and their bioavailability

    Science.gov (United States)

    Roba, Carmen; Baciu, Calin; Rosu, Cristina; Pistea, Ioana; Ozunu, Alexandru

    2015-04-01

    Keywords: heavy metals, soil contamination, bioavailability, Romania The fate of various metals, including chromium, nickel, copper, manganese, mercury, cadmium, and lead, and metalloids, like arsenic, antimony, and selenium, in the natural environment is of great concern, particularly in the vicinity of former mining sites, dumps, tailings piles, and impoundments, but also in urban areas and industrial centres. Most of the studies focused on the heavy metal pollution in mining areas present only the total amounts of metals in soils. The bioavailable concentration of metals in soil may be a better predictor for environmental impact of historical and current dispersion of metals. Assessment of the metal bioavailability and bioaccessibility is critical in understanding the possible effects on soil biota. The bioavailability of metals in soil and their retention in the solid phase of soil is affected by different parameters like pH, metal amount, cation-exchange capacity, content of organic matter, or soil mineralogy. The main objectives of the present study were to determine the total fraction and the bioavailable fraction of Cu, Cd, Pb and Zn from soil in a well-known mining region in Romania, and to evaluate the influence of soil pH on the metal bioavailability in soil. The heavy metal contents and their bioavailability were monitored in a total of 50 soil samples, collected during June and July 2014 from private gardens of the inhabitants from Baia-Mare area. The main mining activities developed in the area consisted of non-ferrous sulphidic ores extraction and processing, aiming to obtain concentrates of lead, copper, zinc and precious metals. After 2006, the metallurgical industry has considerably reduced its activity by closing or diminishing its production capacity. The analysed soil samples proved to have high levels of Pb (50 - 830 mg/kg), Cu (40 - 600 mg/kg), Zn (100 - 700 mg/kg) and Cd (up to 10 mg/kg). The metal abundance in the total fraction is

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  19. Bioavailability of Organic Solvents in Soils: Input into Biologically Based Dose-Response Models for Human Risk Assessments - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Webster, R. C.

    2000-10-01

    Compared to dermal exposures with neat or aqueous compound, little is understood about the dermal bioavailability of solvents in soil, dust, sludge, or sediment matrices. Therefore, research in this project was designed to provide an understanding of the influence of various environmental factors on the kinetics and bioavailability of solvent-laden soils.

  20. 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…

  1. 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...

  2. Estimation of digestive stability and bioavailability of chlorophylls by an in vitro digestion/Caco-2 cell culture model

    OpenAIRE

    Gallardo Guerrero, Lourdes; Gandul-Rojas, Beatriz; Mínguez Mosquera, María Isabel

    2006-01-01

    The aim of this work was to study the effect of food matrix both on the chlorophyll pigment transformations and on their micellarization as a measure of bioavailability, using an two-stage in vitro digestion model. We also validate the above mentioned bioavailability measurement by evaluating the absorption of the micellarized chlorophyll pigments by Caco-2 human intestinal cell cultures.

  3. 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)

    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.

  4. Self nanoemulsifying drug delivery system (SNEDDS) of rosuvastatin calcium: design, formulation, bioavailability and pharmacokinetic evaluation.

    Science.gov (United States)

    Balakumar, Krishnamoorthy; Raghavan, Chellan Vijaya; selvan, Natarajan Tamil; prasad, Ranganathan Hari; Abdu, Siyad

    2013-12-01

    The aim of the present study is to improve solubility and bioavailability of Rosuvastatin calcium using self nanoemulsifying drug delivery system (SNEDDS). Self emulsifying property of various oils including essential oils was evaluated with suitable surfactants and co-surfactants. Ternary phase diagrams were constructed based on Rosuvastatin calcium solubility analysis for optimizing the system. The prepared formulations were evaluated for self emulsifying time, robustness to dilution, droplet size determination and zeta potential analysis. The system was found to be robust in different pH media and dilution volume. The globule size of the optimized system was less than 200nm which could be an acceptable nanoemulsion size range. The zeta potential of the selected CN 7 SNEDDS formulation (cinnamon oil 30%; labrasol 60%; Capmul MCM C8 10%) was -29.5±0.63 with an average particle size distribution of 122nm. In vitro drug release studies showed remarkable increase in dissolution of CN7 SNEDDS compared to marketed formulation. In house developed HPLC method for determination of Rosuvastatin calcium in rat plasma was used in the bioavailability and pharmacokinetic evaluation. The relative bioavailability of self nanoemulsified formulation showed an enhanced bioavailability of 2.45 times greater than that of drug in suspension. The obtained plasma drug concentration data was processed with PKSolver 2.0 and it was best fit into the one compartment model. PMID:24012665

  5. SELF EMULSIFYING DRUG DELIVERY SYSTEM: A METHOD FOR ENHANCEMENT OF BIOAVAILABILITY

    Directory of Open Access Journals (Sweden)

    Urvashi Goyal et al.

    Full Text Available Oral route is the easiest and most convenient route of drug administration, being non invasive and cost effective, thereby leading worldwide drug delivery market. But major problem encountered in oral formulations (as estimated more than 50 % of oral formulations are found to be poorly aqueous soluble, is low bioavailability, giving rise to further problems like, high inter and intra subject variability, lack of dose uniformity and finally leading to therapeutic failure. The challenging task is to increase the bioavailability of drugs. Number of technological strategies are investigated and reported in literature for improving bioavailability like solid dispersions, cyclodextrins, micronization etc. But Self-microemulsifying Drug Delivery System (SMEDDS have gained exposure for their ability to increase solubility and bioavailability of poorly aqueous soluble drugs with reduction in dose and also drugs are protected from hostile environment in gut. SMEDDS are isotropic mixture of oil, surfactant, drug and sometimes containing co-surfactant and administered orally which on mild agitation with GI fluids forms o/w microemulsion. This review gives complete overview of SMEDDS but special attention has been paid to formulation design, evaluation and little emphasis on application of SMEDDS.

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

    DEFF Research Database (Denmark)

    Krogholm, Kirstine Suszkiewicz; Bredsdorff, Lea; Knuthsen, Pia; Haraldsdottir, J.; Rasmussen, S. E

    2010-01-01

    The bioavailability and urinary excretion of three dietary flavonoids, quercetin, hesperetin and naringenin, were investigated. Ten healthy men were asked to consume a 'juice mix' containing equal amounts of the three flavonoids, and their urine and plasma samples were collected. The resulting mean...

  7. Bioavailability as an issue in risk assessment and management of food cadmium: A review

    Science.gov (United States)

    The bioavailability of cadmium (Cd) from food could be an important determinant of the risk potential of dietary Cd to the consumer. This review summarizes recent work that describes the effects of marginal deficiencies of the essential nutrients zinc (Zn), iron (Fe), and calcium (Ca) on the enhance...

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

  10. Application of a Tenax Model to Assess Bioavailability of Polychlorinated Biphenyls in Field Sediments

    Science.gov (United States)

    Recent literature has shown that bioavailability-based techniques, such as Tenax extraction, can estimate sediment exposure to benthos. In a previous study by the authors,Tenax extraction was used to create and validate a literature-based Tenax model to predict oligochaete bioac...

  11. 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

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  13. BARIUM BIOAVAILABILITY AS THE CHLORIDE, SULFATE, OR CARBONATE SALT IN THE RAT

    Science.gov (United States)

    This study was conducted to determine how the bioavailability of a low concentration of barium (Ba) in drinking water is affected by anion speciation. Male Sprague Dawley rats weighing 250-300 grams were maintained on a diet of less than 1 mg Ba/kg of food for at least 1 month pr...

  14. A Randomized Steady-State Bioavailability Study of Synthetic versus Natural (Kiwifruit-Derived Vitamin C

    Directory of Open Access Journals (Sweden)

    Margreet C. M. Vissers

    2013-09-01

    Full Text Available Whether vitamin C from wholefoods has equivalent bioavailability to a purified supplement remains unclear. We have previously showed that kiwifruit provided significantly higher serum and tissue ascorbate levels than synthetic vitamin C in a genetically vitamin C-deficient mouse model, suggesting a synergistic activity of the whole fruit. To determine if these results are translatable to humans, we carried out a randomized human study comparing the bioavailability of vitamin C from kiwifruit with that of a vitamin C tablet of equivalent dosage. Thirty-six young non-smoking adult males were randomized to receive either half a gold kiwifruit (Actinidia Chinensis var. Hort 16A per day or a comparable vitamin C dose (50 mg in a chewable tablet for six weeks. Ascorbate was monitored weekly in fasting venous blood and in urine, semen, leukocytes, and skeletal muscle (vastus lateralis pre- and post-intervention. Dietary intake of vitamin C was monitored using seven day food and beverage records. Participant ascorbate levels increased in plasma (P < 0.001, urine (P < 0.05, mononuclear cells (P < 0.01, neutrophils (P < 0.01 and muscle tissue (P < 0.001 post intervention. There were no significant differences in vitamin C bioavailability between the two intervention groups in any of the fluid, cell or tissue samples tested. Overall, our study showed comparable bioavailability of synthetic and kiwifruit-derived vitamin C.

  15. A randomized steady-state bioavailability study of synthetic versus natural (kiwifruit-derived) vitamin C.

    Science.gov (United States)

    Carr, Anitra C; Bozonet, Stephanie M; Pullar, Juliet M; Simcock, Jeremy W; Vissers, Margreet C M

    2013-09-01

    Whether vitamin C from wholefoods has equivalent bioavailability to a purified supplement remains unclear. We have previously showed that kiwifruit provided significantly higher serum and tissue ascorbate levels than synthetic vitamin C in a genetically vitamin C-deficient mouse model, suggesting a synergistic activity of the whole fruit. To determine if these results are translatable to humans, we carried out a randomized human study comparing the bioavailability of vitamin C from kiwifruit with that of a vitamin C tablet of equivalent dosage. Thirty-six young non-smoking adult males were randomized to receive either half a gold kiwifruit (Actinidia Chinensis var. Hort 16A) per day or a comparable vitamin C dose (50 mg) in a chewable tablet for six weeks. Ascorbate was monitored weekly in fasting venous blood and in urine, semen, leukocytes, and skeletal muscle (vastus lateralis) pre- and post-intervention. Dietary intake of vitamin C was monitored using seven day food and beverage records. Participant ascorbate levels increased in plasma (P < 0.001), urine (P < 0.05), mononuclear cells (P < 0.01), neutrophils (P < 0.01) and muscle tissue (P < 0.001) post intervention. There were no significant differences in vitamin C bioavailability between the two intervention groups in any of the fluid, cell or tissue samples tested. Overall, our study showed comparable bioavailability of synthetic and kiwifruit-derived vitamin C. PMID:24067392

  16. Proximate, mineral, and antinutrient compositions of indigenous Okra (Abelmoschus esculentus) pod accessions: implications for mineral bioavailability.

    Science.gov (United States)

    Gemede, Habtamu Fekadu; Haki, Gulelat Desse; Beyene, Fekadu; Woldegiorgis, Ashagrie Z; Rakshit, Sudip Kumar

    2016-03-01

    The promotion and consumption of indigenous vegetables could help to mitigate food insecurity and alleviate malnutrition in developing countries. Nutrient and antinutrient compositions of eight accessions of Okra Pods were investigated. Molar ratios and mineral bioavailability of Okra pod accessions were also calculated and compared to the critical values to predict the implications for mineral bioavailability. Proximate and mineral composition of Okra pod accessions were determined using standard methods of Association of Official Analytical Chemists. The result of the study revealed that the proximate composition (g/100 g) in dry weight basis was significantly (P potassium (122.59-318.20), zinc (3.83-6.31), phosphorus (25.62-59.72), and sodium (3.33-8.31) on dry weight bases. The Okra Pods of "OPA#6" accession contained significantly higher amounts of crude protein, total ash, crude fat, calcium, iron, and zinc than all other accessions evaluated in this study. The results of antinutrients analysis showed that, except phytate, tannin, and oxalate contents of all the accessions were significantly (P bioavailability of calcium, iron, and zinc in these accessions could be high. The results of the study revealed that Okra pod contain appreciable amount of vital nutrients like protein, fiber, calcium, iron, and zinc and low in antinutrient contents with high mineral bioavailability. Therefore, increase in the production and consumption of these nutrient-rich indigenous Okra pods will help to supplement/formulate the diets and alleviate the problems associated with malnutrition in the country. PMID:27004112

  17. 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 ( 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. PMID:26495827

  18. BIOAVAILABILITY OF SELENIUM FROM MEAT AND BROCCOLI AS DETERMINED BY RETENTION AND DISTRIBUTION OF SE75

    Science.gov (United States)

    Meat is the single greatest source of selenium (Se) in the North American diet. Although not naturally enriched in Se, broccoli will accumulate Se when grown on high Se soils. Previous reports have demonstrated that Se from meat is highly bioavailable whereas Se from broccoli has poor bioavailabil...

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

    International Nuclear Information System (INIS)

    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

  20. 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,

  1. Dissolved oxygen as an indicator of bioavailable dissolved organic carbon in groundwater

    Science.gov (United States)

    Chapelle, Francis H.; Bradley, Paul M.; McMahon, Peter B.; Kaiser, Karl; Benner, Ron

    2012-01-01

    Concentrations of dissolved oxygen (DO) plotted vs. dissolved organic carbon (DOC) in groundwater samples taken from a coastal plain aquifer of South Carolina (SC) showed a statistically significant hyperbolic relationship. In contrast, DO-DOC plots of groundwater samples taken from the eastern San Joaquin Valley of California (CA) showed a random scatter. It was hypothesized that differences in the bioavailability of naturally occurring DOC might contribute to these observations. This hypothesis was examined by comparing nine different biochemical indicators of DOC bioavailability in groundwater sampled from these two systems. Concentrations of DOC, total hydrolysable neutral sugars (THNS), total hydrolysable amino acids (THAA), mole% glycine of THAA, initial bacterial cell counts, bacterial growth rates, and carbon dioxide production/consumption were greater in SC samples relative to CA samples. In contrast, the mole% glucose of THNS and the aromaticity (SUVA254) of DOC was greater in CA samples. Each of these indicator parameters were observed to change with depth in the SC system in a manner consistent with active biodegradation. These results are uniformly consistent with the hypothesis that the bioavailability of DOC is greater in SC relative to CA groundwater samples. This, in turn, suggests that the presence/absence of a hyperbolic DO-DOC relationship may be a qualitative indicator of relative DOC bioavailability in groundwater systems.

  2. Bioavailability assessment of ketoprofen incorporated in gelled self-emulsifying formulation: A technical note

    OpenAIRE

    Patil, Pradeep R.; Praveen, S.; Shobha Rani, R. H.; Paradkar, Anant R.

    2005-01-01

    Based on the results of the present study, it is apparent that the gelled SEF containing KPF did not significantly alter its bioavailability as compared with that of an immediate release solid dosage form when administered to human volunteers by the oral route.

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

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    Science.gov (United States)

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

  5. Organically complexed iron enhances bioavailability of antimony to maize (Zea mays) seedlings in organic soils.

    Science.gov (United States)

    Ptak, Corey; McBride, Murray

    2015-12-01

    Antimony (Sb) is a metalloid belonging to group 15 of the periodic table. Chemical similarities between arsenic (As) and Sb produce concerns about potential health effects of Sb and enrichment in the environment. Antimony is found in oxic environments predominately as an oxyanionic species, antimonite (Sb[OH](6-)). As a result of its net negative charge, Sb[OH](6-) was not initially predicted to have strong interactions with natural organic matter. Oxyanionic species could bind the negatively charged organic matter via a ternary complexation mechanism, in which cationic metals mediate the strong association between organic matter functional groups and oxyanions. However, these interactions are poorly understood in how they influence the bioavailability of oxyanionic contaminants to plants. Iron (Fe) additions to organic soils have been found to increase the number of organically complexed Fe sites suitable for Sb exchange, resulting in a reduced bioavailable fraction of Sb. The bioavailability of Sb to maize seedlings as a function of organically complexed Fe was examined using a greenhouse study. A significant increase in plant tissue Sb was observed as organically complexed Fe increased, which was not predicted by methods commonly used to assess bioavailable Sb. Extraction of soils with organic acids common to the maize rhizosphere suggested that organic acid exudation can readily mobilize Sb bound by organic Fe complexes. PMID:26076768

  6. 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.

  7. Reduction of bioavailability and leachability of heavy metals during vermicomposting of water hyacinth.

    Science.gov (United States)

    Singh, Jiwan; Kalamdhad, Ajay S

    2013-12-01

    Vermicomposting of water hyacinth is a good alternative for the treatment of water hyacinth (Eichhornia crassipes) and subsequentially, beneficial for agriculture purposes. The bioavailability and leachability of heavy metals (Zn, Cu, Mn, Fe, Ni, Pb, Cd, and Cr) were evaluated during vermicomposting of E. crassipes employing Eisenia fetida earthworm. Five different proportions (trials 1, 2, 3, 4, and 5) of cattle manure, water hyacinth, and sawdust were prepared for the vermicomposting process. Results show that very poor biomass growth of earthworms was observed in the highest proportion of water hyacinth (trial 1). The water soluble, diethylenetriaminepentaacetic acid (DTPA) extractable, and leachable heavy metals concentration (percentage of total heavy metals) were reduced significantly in all trials except trial 1. The total concentration of some metals was low but its water soluble and DTPA extractable fractions were similar or more than other metals which were present in higher concentration. This study revealed that the toxicity of metals depends on bioavailable fraction rather than total metal concentration. Bioavailable fraction of metals may be toxic for plants and soil microorganisms. The vermicomposting of water hyacinth by E. fetida was very effective for reduction of bioavailability and leachability of selected heavy metals. Leachability test confirmed that prepared vermicompost is not hazardous for soil, plants, and human health. The feasibility of earthworms to mitigate the metal toxicity and to enhance the nutrient profile in water hyacinth vermicompost might be useful in sustainable land renovation practices at low-input basis. PMID:23757026

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

    International Nuclear Information System (INIS)

    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-1) and Zn (2602 mg kg-1), whilst the second, from Valencia, had elevated concentrations of Cu (72 mg kg-1) and Pb (190 mg kg-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 CaCl2 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-1 soil) had only a limited effect on metal uptake by plants. The metal-solubilising effect of EDTA was shorter-lived in the less contaminated, more highly calcareous Valencia soil. When correlation coefficients were calculated for plant tissue and bioavailable metals, the clearest relationships were for Beta maritima and radish

  9. Production of bioavailable and refractory dissolved organic matter by coastal heterotrophic microbial populations

    Science.gov (United States)

    Lønborg, Christian; Álvarez-Salgado, Xosé A.; Davidson, Keith; Miller, Axel E. J.

    2009-05-01

    Production of dissolved organic matter (DOM) by heterotrophic microbial communities isolated from Loch Creran (Scotland) was studied in time course incubations in which cells were re-suspended in artificial seawater amended with variable proportions of glucose, ammonium and phosphate. The incubation experiments demonstrated that microheterotrophs released part of the substrate as new DOM, with a production efficiency of 11 ± 1% for DOC, 18 ± 2% for DON and 17 ± 2% for DOP. Estimating the impact of this production in Loch Creran, showed that from 3 ± 1% (DOC) to 72 ± 16% (DOP) of DOM could originate from the heterotrophic microbial community. The produced DOM (PDOM) was both bioavailable (BDOM) and refractory (RDOM). Bioavailability as assessed by the difference between the maximum and the end DOM concentration, was generally higher than found in natural systems, with DOP (73 ± 15%, average ± SD) more bioavailable than DON (70 ± 15%), and DON than DOC (34 ± 13%). The stoichiometry of PDOM was linked to both nutrient uptake and BDOM ratios. Absorption and fluorescence of DOM increased significantly during the incubation time, indicating that microheterotrophs were also a source of coloured DOM (CDOM) and that they produce both bioavailable protein-like and refractory humic-like fluorophores.

  10. 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...

  11. Predicting zinc bioavailability to wheat improved by integrating pH dependent nonlinear root suface adsorption

    NARCIS (Netherlands)

    Duffner, A.; Hoffland, E.; Weng, L.P.; Zee, van der S.E.A.T.M.

    2013-01-01

    Aim Our aim was to improve the prediction of Zn bioavailability to wheat grown on low-Zn soils. The classical approach that directly relates Zn in a certain soil extract to Zn uptake has been shown to be inadequate in many cases. We tested a stepwise approach where the steps of the uptake process ar

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

    NARCIS (Netherlands)

    Olthof, M.R.

    2001-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-15

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

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

    Science.gov (United States)

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

  15. Skin permeation mechanism and bioavailability enhancement of celecoxib from transdermally applied nanoemulsion

    Directory of Open Access Journals (Sweden)

    Ali Javed

    2008-07-01

    Full Text Available Abstract Background Celecoxib, a selective cyclo-oxygenase-2 inhibitor has been recommended orally for the treatment of arthritis and osteoarthritis. Long term oral administration of celecoxib produces serious gastrointestinal side effects. It is a highly lipophilic, poorly soluble drug with oral bioavailability of around 40% (Capsule. Therefore the aim of the present investigation was to assess the skin permeation mechanism and bioavailability of celecoxib by transdermally applied nanoemulsion formulation. Optimized oil-in-water nanoemulsion of celecoxib was prepared by the aqueous phase titration method. Skin permeation mechanism of celecoxib from nanoemulsion was evaluated by FTIR spectral analysis, DSC thermogram, activation energy measurement and histopathological examination. The optimized nanoemulsion was subjected to pharmacokinetic (bioavailability studies on Wistar male rats. Results FTIR spectra and DSC thermogram of skin treated with nanoemulsion indicated that permeation occurred due to the disruption of lipid bilayers by nanoemulsion. The significant decrease in activation energy (2.373 kcal/mol for celecoxib permeation across rat skin indicated that the stratum corneum lipid bilayers were significantly disrupted (p Conclusion Results of skin permeation mechanism and pharmacokinetic studies indicated that the nanoemulsions can be successfully used as potential vehicles for enhancement of skin permeation and bioavailability of poorly soluble drugs.

  16. Pharmacokinetics and oral bioavailability of amoxicillin in chicken infected with caecal coccidiosis.

    Science.gov (United States)

    Kandeel, M

    2015-10-01

    Chicken infected with caecal coccidiosis (Eimeria tenella) was used to evaluate the effect of coccidiosis on the pharmacokinetic and bioavailability of amoxicillin. The level of amoxicillin was estimated by high-performance chromatography (HPLC) to calculate the pharmacokinetic parameters and oral bioavailability. For i.v. injection of amoxicillin, Vd and CL were 0.29 and 0.27 (mg/kg)/(μg/mL)/h, respectively. Compared with healthy chicken, intravenous injection of amoxicillin in the infected chicken showed higher distribution and elimination constants, delayed clearance and statistically significant higher AUC and MRT. Oral administration in healthy chicken was accompanied by rapid absorption and high bioavailability with Tmax , Cmax and F about 1.03 h, 3.26 μg/mL and 40.2, respectively. Furthermore, oral administration in the infected chicken produced higher mean absorption time, delayed Tmax, lower Cmax, smaller AUC value and lower bioavailability (16.76). Based on these results, monitoring and adjustment of amoxicillin dosing could be practiced during the presence of coccidiosis. The measured Cmax values suggest the administration of 1.3-folds of the normal dose to maintain the normal maximal serum concentrations of amoxicillin in chicken infected with caecal coccidiosis. PMID:25623275

  17. Bioavailability of metals from diesel engine emissions in simulated lung fluids

    Czech Academy of Sciences Publication Activity Database

    Coufalík, Pavel; Mikuška, Pavel; Křůmal, Kamil; Večeřa, Zbyněk; Vojtíšek, M.; Matoušek, Tomáš

    2014. s. 120-120. [International Symposium on Environmental Analytical Chemistry /38./. 17.06.2014-20.06.2014, Lausanne] R&D Projects: GA ČR GA13-01438S; GA ČR(CZ) GA14-25558S Institutional support: RVO:68081715 Keywords : metal * bioavailability * particulate matter Subject RIV: CB - Analytical Chemistry, Separation

  18. 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.

  19. 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. PMID:27131817

  20. Relative Bioavailability of Three Newly Developed Albendazole Formulations: a Randomized Crossover Study with Healthy Volunteers

    OpenAIRE

    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-β-cyclodextrin as an excipient was enhanced 4.3- and 9.7-fold compared to the results seen with commercial tablets. Administration of macrogol suppositories did not result in measurable plasma concentrations of albendazole sulfoxide.

  1. Selenium from Pinto Beans is Bioavailable to Support Bone Structure in Mice

    Science.gov (United States)

    Deficiency of selenium (Se), an essential trace mineral for animals and humans, has been shown to induce growth retardation and to impair bone metabolism. The objective of the study was to determine whether Se from pinto beans (SeBean) is as bioavailable as Se from selenomethionine (SeMet) to suppor...

  2. Time and moisture effects on total and bioavailable copper in soil water extracts

    DEFF Research Database (Denmark)

    Tom-Petersen, Andreas; Hansen, H.C.B.; Nybroe, O.

    2004-01-01

    ([Cu](tot)) were performed using furnace atomic absorption spectrometry. An in vitro assay employing a Cu-specific Pseudomonas fluorescens reporter strain was used to estimate Cu that was biologically available to the reporter strain. We refer to this copper fraction as "bioavailable," [Cu](bio). We...

  3. Bioavailability of classical and novel flame retardants: Effect of fullerene presence.

    Science.gov (United States)

    Santín, Giselle; Eljarrat, Ethel; Barceló, Damià

    2016-09-15

    To understand the behavior of some emerging flame retardants (FRs) in the environment, a nonexhaustive extraction using Tenax was applied to study their behavior in aquatic ecosystems. Desorption of 8 polybrominated diphenyl ethers (PBDEs), 8 methoxylated PBDEs, 3 emerging brominated FRs and 6 halogenated norbornenes from sediments spiked in the laboratory was studied. Results showed that emerging FRs have a similar bioavailability than that of legacy FRs, already banned. In addition, some parameters such as sediment total organic carbon (TOC), aging or nanomaterial (NMs) presence in the sediment were modified in order to study their effects on the bioavailability of FRs. Bioavailability increases with a diminution of sediment TOC, while diminishes with an increase of aging. The study of effect of NM presence was performed at three different pH (acidic, neutral and basic), and for the three scenarios, FR bioavailability decreased with NM presence. The retention of pollutants in the sediment seems to be favoured by NM presence, minimizing their impact on living organisms. PMID:27177136

  4. SUPPLEMENTAL DIETARY INULIN AFFECTS BIOAVAILABILITY OF IRON PRESENT IN CORN AND SOYBEAN MEAL TO YOUNG PIGS

    Science.gov (United States)

    Iron deficiency represents one of the most common global nutritional disorders in humans. Our objective was to determine whether and how supplemental inulin improved bioavailability of iron intrinsically present in a corn-soybean meal based diet to young pigs for hemoglobin synthesis. In Experimen...

  5. Effect of pomegranate pretreatment on the oral bioavailability of buspirone in male albino rabbits

    Directory of Open Access Journals (Sweden)

    M Sarangapani

    2011-10-01

    Full Text Available Background and the Purpose of the study: Many drug substances and variety of naturally occurring dietary or herbal components are capable of interaction with the CYP enzyme system. The aim of the study was to investigate the effect of pomegranate juice pretreatment on the bioavailability of buspirone in rabbits. Methods: White New Zealand rabbits weighing 2.1±0.13 Kg were selected for study. The bioavailability of buspirone after pre-treatment with pomegranate juice (10 ml Kg-1 for seven days was compared with an oral solution of 10 mg kg-1 of buspirone in distilled water. Animals were allowed free access to food and water, until night prior to dosing and were fasted for 10 hrs. In the first phase oral solution (10 mg kg-1 was administered through feeding tube followed by rinsing with 10 ml of water. In the second phase, the group was pretreated with pomegranate juice for 7 days and study was conducted after 15 days of washout period. Results and conclusion: The results showed that there was a significant (p<0.05 difference in the bioavailability of buspirone after pre-treatment with pomegranate juice.This increase in bioavailability might be due to inhibition of CYP3A4. Further studies are required to prove this mechanism in humans.

  6. 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.

  7. Oral bioavailability and pharmacodynamic activity of hesperetin nanocrystals generated using a novel bottom-up technology

    DEFF Research Database (Denmark)

    Shete, Ganesh; Pawar, Yogesh B; Thanki, Kaushik; Jain, Sanyog; Bansal, Arvind Kumar

    2015-01-01

    In the present study, nanocrystalline solid dispersion (NSD) was developed to enhance the release rate and oral bioavailability of hesperetin (HRN). NSD of HRN was prepared using a novel bottom-up technology platform. It is a spray drying based technology to generate solid particles, containing...

  8. Distribution, speciation and bioavailability of Lanthanides in the Rhine-Meuse estuary, The Netherlands

    NARCIS (Netherlands)

    Moermond, C.T.A.; Tijink, J.; Wezel, van A.P.; Koelmans, A.A.

    2001-01-01

    Changing environmental conditions may influence the fate and bioavailability of lanthanides (part of the rare earth elements [Ln]) in estuaries. The aim of this study was to quantify the variation in estuarine lanthanide solid/water distribution, speciation, and bioaccumulation. The latter was studi

  9. 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

  10. IRON BIOAVAILABILITY FROM COMMON RAISIN-CONTAINING FOODS ASSESSED WITH AN IN VITRO DIGESTION/CACO-2 CELL CULTURE MODEL: EFFECTS OF RAISINS

    Science.gov (United States)

    The effects of raisins on iron bioavailability from wheat bran cereal, bread, rice pudding, and granola bars were studied. Iron bioavailability was assessed with an in vitro digestion/Caco-2 cell culture model. Raisins reduced iron bioavailability from all foods, except granola bars. Raisins also...

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

    International Nuclear Information System (INIS)

    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 (Kd) of Cs and Sr were observed as an index of their sorption level. Kd 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

  12. 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

  13. Enhancement of Bioavailability and Pharmacodynamic Effects of Thymoquinone Via Nanostructured Lipid Carrier (NLC) Formulation.

    Science.gov (United States)

    Elmowafy, Mohammed; Samy, Ahmed; Raslan, Mohamed A; Salama, Ayman; Said, Ragab A; Abdelaziz, Abdelaziz E; El-Eraky, Wafaa; El Awdan, Sally; Viitala, Tapani

    2016-06-01

    Thymoquinone (TQ), obtained from black cumin (Nigella sativa), is a natural product with anti-oxidant, anti-inflammatory, and hepatoprotective effects but unfortunately with poor bioavailability. Aiming to improve its poor oral bioavailability, TQ-loaded nanostructured lipid carriers (NLCs) were prepared by high-speed homogenization followed by ultrasonication and evaluated in vitro. Bioavailability and pharmacodynamic studies were also performed. The resultant NLCs showed poor physical homogeneity in Compritol 888 ATO Pluronic F127 system which consequently produced larger particle size and polydispersity index, smaller zeta potential values, and lower short-term (30 days) physical stability than other systems. Encapsulation efficiency percentage (EE%) lied between 84.6 ± 5% and 96.2 ± 1.6%. TQ AUC0-t values were higher in animals treated with NLCs, with a relative bioavailability of 2.03- and 3.97-fold (for F9 and F12, respectively) higher than TQ suspension, indicating bioavailability enhancement by NLC formulation. Hepatoprotective effects of F12 showed significant (P < 0.05) decrease in both serum alanine amino transferase and aspartate amino transferase to reach 305.0 ± 24.88 and 304.7 ± 23.55 U/ml, respectively, when compared with untreated toxic group. Anti-oxidant efficacy of F12 showed significant (P < 0.05) decline of malondialdehyde and elevation of reduced glutatione. This improvement was also confirmed histopathologically. PMID:26304932

  14. Biochemical indicators for the bioavailability of organic carbon in ground water

    Science.gov (United States)

    Chapelle, F.H.; Bradley, P.M.; Goode, D.J.; Tiedeman, C.; Lacombe, P.J.; Kaiser, K.; Benner, R.

    2009-01-01

    The bioavailability of total organic carbon (TOC) was examined in ground water from two hydrologically distinct aquifers using biochemical indicators widely employed in chemical oceanography. Concentrations of total hydrolyzable neutral sugars (THNS), total hydrolyzable amino acids (THAA), and carbon-normalized percentages of TOC present as THNS and THAA (referred to as "yields") were assessed as indicators of bioavailability. A shallow coastal plain aquifer in Kings Bay, Georgia, was characterized by relatively high concentrations (425 to 1492 ??M; 5.1 to 17.9 mg/L) of TOC but relatively low THNS and THAA yields (???0.2%-1.0%). These low yields are consistent with the highly biodegraded nature of TOC mobilized from relatively ancient (Pleistocene) sediments overlying the aquifer. In contrast, a shallow fractured rock aquifer in West Trenton, New Jersey, exhibited lower TOC concentrations (47 to 325 ??M; 0.6 to 3.9 mg/L) but higher THNS and THAA yields (???1% to 4%). These higher yields were consistent with the younger, and thus more bioavailable, TOC being mobilized from modern soils overlying the aquifer. Consistent with these apparent differences in TOC bioavailability, no significant correlation between TOC and dissolved inorganic carbon (DIC), a product of organic carbon mineralization, was observed at Kings Bay, whereas a strong correlation was observed at West Trenton. In contrast to TOC, THNS and THAA concentrations were observed to correlate with DIC at the Kings Bay site. These observations suggest that biochemical indicators such as THNS and THAA may provide information concerning the bioavailability of organic carbon present in ground water that is not available from TOC measurements alone.

  15. 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 (typically<10% of the total). Much of the non-bioavailable form of copper 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. PMID:24080008

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

    International Nuclear Information System (INIS)

    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 > Al2O3 > Fe3O4 > MnO2 > 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 > Fe3O4 > Al2O3 > FeOOH > MnO2, while by citric acid: Al(OH)3 ≥ Al2O3 > Fe3O4 > FeOOH > MnO2. 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 MnO2 adsorbed Cd was least desorbable by LMWOAs hence constituted the least bioavailable Cd species adsorbed on the oxide minerals.

  17. The mobility, bioavailability, and human bioaccessibility of trace metals in urban soils of Hong Kong

    International Nuclear Information System (INIS)

    Trace metals in soils may pose risks to both ecosystem and human health, especially in an urban environment. However, only a fraction of the metal content in soil is mobile and/or available for biota uptake and human ingestion. Various environmental availabilities of trace metals (Cu, Pb and Zn) in topsoil from highly urbanized areas of Hong Kong to plants, organisms, and humans, as well as the leaching potential to groundwater were evaluated in the present study. Forty selected soil samples were extracted with 0.11 M acid acetic, 0.01 M calcium chloride, 0.005 M diethylenetriaminepentaacetic acid, and simplified physiologically based extraction tests (PBET) for the operationally defined mobilizable, effectively bioavailable, potentially bioavailable, and human bioaccessible metal fractions, respectively. The metals were generally in the order of Zn > Cu ∼ Pb for both mobility (24%, 7.6%, 6.7%) and effective bioavailability (2.8%, 0.9%, 0.6%), Pb (18%) > Cu (13%) > Zn (7.4%) for potential bioavailability, and Pb (59%) ∼ Cu (58%) > Zn (38%) for human bioaccessibility. Although the variations in the different available concentrations of metals could mostly be explained by total metal concentrations in soil, the regression model predictions were further improved by the incorporation of soil physicochemical properties (pH, OM, EC). The effectively bioavailable Zn and Pb were mostly related to soil pH. Anthropogenic Pb in urban soils tended to be environmentally available as indicated by Pb isotopic composition analysis. Combining various site-specific environmental availabilities might produce a more realistic estimation for the integrated ecological and human health risks of metal contamination in urban soils.

  18. Enhancing the Delivery of Resveratrol in Humans: If Low Bioavailability is the Problem, What is the Solution?

    Directory of Open Access Journals (Sweden)

    James M. Smoliga

    2014-10-01

    Full Text Available Resveratrol has emerged as a leading candidate for improving healthspan through potentially slowing the aging process and preventing chronic diseases. The poor bioavailability of resveratrol in humans has been a major concern for translating basic science findings into clinical utility. Although a number of positive findings have emerged from human clinical trials, there remain many conflicting results, which may partially be attributed to the dosing protocols used. A number of theoretical solutions have been developed to improve the bioavailability of resveratrol, including consumption with various foods, micronized powders, combining it with additional phytochemicals, controlled release devices, and nanotechnological formulations. While laboratory models indicate these approaches all have potential to improve bioavailability of resveratrol and optimize its clinical utility, there is surprisingly very little data regarding the bioavailability of resveratrol in humans. If bioavailability is indeed a limitation in the clinical utility of resveratrol, there is a need to further explore methods to optimize bioavailability in humans. This review summarizes the current bioavailability data, focusing on data from humans, and provides suggested directions for future research in this realm.

  19. Effect of Inorganic and Organic Ligands on the Bioavailability of Methylmercury as Determined by Using a mer-lux Bioreporter

    OpenAIRE

    Ndu, Udonna; Mason, Robert P.; Zhang, Huan; Lin, Senjie; Visscher, Pieter T.

    2012-01-01

    A mer-lux bioreporter was constructed to assess the bioavailability of methylmercury [CH3Hg(II)] in Escherichia coli. The bioreporter was shown to be sensitive, with a detection limit of 2.5 nM CH3Hg(II), and was used to investigate the effects of chlorides, humic acids, and thiols on the bioavailability of CH3Hg(II) in E. coli. It was found that increasing the concentration of chlorides resulted in an increase in CH3Hg(II) bioavailability, suggesting that there was passive diffusion of the n...

  20. Bioavailability of PCDDs and PCDFs adsorbed on fly ash in rat, guinea pig and Syrian golden hamster

    Energy Technology Data Exchange (ETDEWEB)

    van de Berg, M.; de Vroom, E.; van Greevenbroek, M.; Olie, K.

    1985-01-01

    In the environment PCDDs and PCDFs often occur in an adsorbed state in soil, sediment or combustion residues. Detailed information about physical, chemical and biological properties is available only for 2,3,7,8-TCDD and to a lesser extent for 2,3,7,8-TCDF. Information about the bioavailability of PCDDs and PCDFs in the adsorbed state is also very limited. The authors have reported earlier about the bioavailability of these compounds from fly ash in the rat. In this paper they report the bioavailability of these compounds from fly ash of a municipal incinerator in three animal species, during a one to three month feeding study.

  1. Total and bioavailable PAH concentrations in biochar - a future soil improver

    Science.gov (United States)

    Hilber, I.; Blum, F.; Hale, S.; Cornelissen, G.; Schmidt, H. P.; Bucheli, T. D.

    2012-04-01

    Biochar is pyrolyzed organic feedstock. It has become more and more important as soil conditioner and received broad attention as a possible measure against climate change. Polycyclic aromatic hydrocarbons (PAHs) are formed during biochar production due to incomplete combustion. These PAHs will enter the environment when the biochar is applied as soil conditioner to avoid leaching of nutrients, to increase microbial biomass and activity, to remediate the soil of organic pollutants, etc. Such positive effects are undermined if PAH exposure is concomitantly increased. We have determined the total PAH concentrations of about 40 commercially produced biochars with an analytical method based on Soxhlet extraction with toluene optimized in our laboratory (Hilber et al.). The bioavailability of the PAHs in these biochars was assessed with polyoxymethylene (POM), a passive sampler, which measures the truly dissolved concentration of organic pollutants in the pore water, according to Hale et al. Samples from total and POM extractions where measured by GC-MS to determine the total and bioavailable concentrations of the 16 EPA PAHs, respectively. Preliminary results showed that the total concentrations of the biochars ranged from 0.4 to 355 mgΣ16 EPA PAH/kgBC. The bioavailable concentrations were in the nanograms per liter for the Σ16 EPA PAH and goes in line with findings of recently published data of Hale et al. The fraction desorbed by POM in relation to the total concentrations is in the permill range. Although the bioavailable concentration appears very small, it has to be considered that biochars might be applied to an agricultural field several times. Thus, the source of amended PAHs to the soil is renewed not only for the bioavailable but also for the total concentration. Biochar applications might become a problem especially for legislation accounting for total concentrations. The only guideline for biochars is from the International Biochar Initiative which set

  2. 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.

  3. Influence of organic matter transformations on the bioavailability of heavy metals in a sludge base compost

    International Nuclear Information System (INIS)

    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)

  4. A method for determination of the absolute pulmonary bioavailability of inhaled drugs: Terbutaline

    International Nuclear Information System (INIS)

    Terbutaline sulfate (4 X 0.250 mg) was given to 11 healthy volunteers by inhalation from a metered dose inhaler (MDI), with and without oral administration of a charcoal slurry. Before the inhalations, the adsorbing capacity of the charcoal slurry was tested. Deuterated terbutaline, 0.125 mg, was given intravenously at the same time as the test doses. The charcoal slurry adsorbed 97% of an oral dose. The oral contribution to the overall systemic bioavailability after inhalation, when charcoal was coadministered, could thus be neglected. After inhalation of terbutaline, 9.1% of the dose was deposited in the lungs and an additional 6.7% was systemically available via the oral route. The method presented measures the absolute pulmonary bioavailability after inhalation from a MDI. Since a deuterated analogue is given intravenously together with the inhalations, fewer subjects are needed to obtain reliable data

  5. Radionuclides in produced water from Norwegian oil and gas installations - concentrations and bioavailability

    International Nuclear Information System (INIS)

    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. (author)

  6. Bioavailability of lithium from lithium citrate syrup versus conventional lithium carbonate tablets.

    Science.gov (United States)

    Guelen, P J; Janssen, T J; De Witte, T C; Vree, T B; Benson, K

    1992-10-01

    The bioavailability of lithium citrate syrup was compared with that of regular lithium carbonate tablets in 18 healthy male human volunteers. Blood samples were collected up to 48 h after dosing. Lithium serum concentrations were determined by means of AAS. The absorption rate following oral administration of the syrup was greater (tmax 0.8 h) than following administration of regular tablets (tmax 1.4 h). Maximum lithium serum concentrations, however, were only about 10 per cent higher after syrup dosing and serum concentrations resulting from syrup and tablets were almost superimposable from 2 h after dosing. The terminal half-life of lithium was found to be 22 h after syrup as well as after tablet dosing. No side-effects were observed during the study. The bioavailability of lithium from syrup relative to tablets was found to be bioequivalent with respect to the maximum lithium serum concentration and the extent of drug absorption (AUC). PMID:1489941

  7. Modulation of carcinogen bioavailability by immunisation with benzo[a]pyrene-conjugate vaccines.

    Science.gov (United States)

    Grova, Nathalie; Prodhomme, Emmanuel J F; Schellenberger, Mario T; Farinelle, Sophie; Muller, Claude P

    2009-06-24

    Benzo[a]pyrene (B[a]P) conjugate vaccines based on ovalbumin, tetanus toxoid and diphtheria toxoid (DT) as carrier proteins were developed to investigate the effect of specific antibodies on the bioavailability of this ubiquitous carcinogen and its metabolites. After metabolic activation of this prototype carcinogen, B[a]P forms DNA adducts which initiate chemical carcinogenesis. B[a]P-DT conjugate induced the most robust immune response. The antibodies reacted not only with B[a]P but also with the proximate carcinogen 7,8-diol-B[a]P. Antibodies modulated the bioavailability of B[a]P and its metabolic activation in a dose-dependent manner by sequestration in the blood. Our results showed that this immune prophylactic strategy influences the pharmacokinetic of B[a]P and further studies to investigate their effects on chemical carcinogenesis are warranted. PMID:19406187

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

    International Nuclear Information System (INIS)

    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 (Bf), 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

  9. Nanomemulsion of megestrol acetate for improved oral bioavailability and reduced food effect.

    Science.gov (United States)

    Li, Yixian; Song, Chung Kil; Kim, Min-Kyoung; Lim, Hyosang; Shen, Qingbo; Lee, Don Haeng; Yang, Su-Geun

    2015-10-01

    Megestrol acetate (MGA) belongs to the BCS class II drugs with low solubility and high permeability, and its oral absorption in conventional dosage form MGA microcrystal suspension (MGA MS) is very limited and greatly affected by food. In this study, MGA nanoemulsion (MGA NE) was formulated based on solubility, phase-diagram and release studies. Then oral bioavailability of MGA NE and MGA MS was evaluated. A randomized two-way crossover trial was conducted on six male dogs under fed and fasting conditions. Blood concentrations of MGA were analyzed using LC-MS/MS. MGA NE yielded 5.00-fold higher oral bioavailability in fasting conditions and displayed more stable absorption profiles after food intake compared with MGA MS. PMID:25893430

  10. Recent Trends of Phytosomes for Delivering Herbal Extract with Improved Bioavailability

    Directory of Open Access Journals (Sweden)

    Arijit Gandhi

    2012-11-01

    Full Text Available In the recent days, most of the prevailing diseases and nutritional disorders are treated with natural medicines. The effectiveness of any herbal medication is dependent on the delivery of effective level of the therapeutically active compound. But a severe limitation exists in their bioavailability when administered orally or by topical applications. Phytosomes are recently introduced herbal formulations that are better absorbed and as a result produced better bioavailability and actions than the conventional phyto molecules or botanical extracts. Phytosomes are produced by a process whereby the standardized plant extract or its constituents are bound to phospholipids, mainly phosphatidylcholine producing a lipid compatible molecular complex. Phytosome exhibit better pharmacokinetic and pharmacodynamic profile than conventional herbal extracts. The present review represents the recent advancesand applications of various standardized herbal extract phytosomes as a tool of drug delivery.

  11. Two novel ternary albendazole-cyclodextrin-polymer systems: dissolution, bioavailability and efficacy against Taenia crassiceps cysts.

    Science.gov (United States)

    Palomares-Alonso, Francisca; González, Cesar Rivas; Bernad-Bernad, Ma Josefa; Montiel, María Dolores Castillo; Hernández, Guadalupe Palencia; González-Hernández, Iliana; Castro-Torres, Nelly; Estrada, Enrique Pinzón; Jung-Cook, Helgi

    2010-01-01

    The effect of two water-soluble polymers: pectin and polyvinylpyrrolidone in combination with beta-cyclodextrin, on the dissolution, bioavailability and cysticidal efficacy of albendazole was evaluated using a commercial suspension as reference product. The dissolution of the albendazole-beta-cyclodextrin-pectin formulation was slow and incomplete (44.7%). No statistical differences in C(max) and AUC were found between this formulation and the reference. Also its cysticidal efficacy (33%) was similar to the reference (38%). The albendazole-beta-cyclodextrin-polyvinylpyrrolidone formulation exhibited the highest dissolution rate (78.5%) and its bioavailability was also significantly increased (2.3-fold). In addition, the cysticidal activity of this formulation (83%) was greater than a commercial suspension. Our results suggest that the ternary system of albendazole-beta-cyclodextrin-polyvinylpyrrolidone could be a potential alternative for the treatment of systemic helmintic diseases and it is worth to continue its preclinical evaluation. PMID:19769931

  12. Experimental determination of the oral bioavailability and bioaccessibility of lead particles

    Directory of Open Access Journals (Sweden)

    Deshommes Elise

    2012-11-01

    Full Text Available Abstract In vivo estimations of Pb particle bioavailability are costly and variable, because of the nature of animal assays. The most feasible alternative for increasing the number of investigations carried out on Pb particle bioavailability is in vitro testing. This testing method requires calibration using in vivo data on an adapted animal model, so that the results will be valid for childhood exposure assessment. Also, the test results must be reproducible within and between laboratories. The Relative Bioaccessibility Leaching Procedure, which is calibrated with in vivo data on soils, presents the highest degree of validation and simplicity. This method could be applied to Pb particles, including those in paint and dust, and those in drinking water systems, which although relevant, have been poorly investigated up to now for childhood exposure assessment.

  13. 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.

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

    International Nuclear Information System (INIS)

    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

  15. Changes in the composition and bioavailability of dissolved organic matter during sea ice formation

    DEFF Research Database (Denmark)

    Jørgensen, Linda; Stedmon, Colin A.; Kaartokallio, Hermanni;

    2015-01-01

    processes such as sea ice formation as the source of the significant DOM removal in the Arctic Ocean. We present the results of a mesocosm experiment designed to investigate how sea ice formation affects DOM composition and bioavailability. We measured the change in different fluorescent dissolved organic...... matter (FDOM) fractions in sea ice, brines (contained in small pores between the ice crystals), and the underlying seawater during a 14 d experiment. Two series of mesocosms were used: one with seawater alone and one with seawater enriched with humic-rich river water. Abiotic processes increased......The Arctic Ocean receives a large amount of terrestrial dissolved organic matter (DOM) from rivers and more than half of this is removed during its passage through the Arctic Ocean. Terrestrial DOM is generally believed to have a low bioavailability and recent studies point to physicochemical...

  16. Triple antioxidant SNEDDS formulation with enhanced oral bioavailability: Implication of chemoprevention of breast cancer.

    Science.gov (United States)

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

    2016-08-01

    The present study aimed to develop quercetin, resveratrol and genistein loaded self-nanoemulsifying drug delivery system (SNEDDS) by QbD approach in order to improve their oral bioavailability and antioxidant potential. The size and PDI of the optimized formulation were found to be curve (AUC) of all three antioxidants. The SNEDDS demonstrated ~4.27 fold enhancement in oral bioavailability of quercetin, ~1.5 fold in case of resveratrol and ~2.8 fold in case of genistein as compared to free antioxidants suspension. Finally, the prophylactic antitumor efficacy of developed formulation was tested against DMBA induced breast cancer model in rats, which demonstrated enhanced abeyance towards the tumor growth as compared to free antioxidants. PMID:27033463

  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. Hydrological regime and salinity alter the bioavailability of Cu and Zn in wetlands

    International Nuclear Information System (INIS)

    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.

  19. Assessment of metal bioavailability in the vineyard soil-grapevine system using different extraction methods.

    Science.gov (United States)

    Vázquez Vázquez, Francisco A; Pérez Cid, Benita; Río Segade, Susana

    2016-10-01

    This study was focused on the assessment of single and sequential extraction methods to predict the bioavailability of metals in the vineyard soil-grapevine system. The modified BCR sequential extraction method and two single-step extraction methods based on the use of EDTA and acetic acid were applied to differently amended vineyard soils. The variety effect was studied on the uptake of metals by leaves and grapes. Most of the elements studied (Ca, Mg, Cu, Fe, Mn, Zn and Pb) were weakly mobilized from vineyard soils, with the exception of Cu and Mn. The determination of total metal content in leaves and grapes showed a different accumulation pattern in the two parts of the vine. A significant relationship was observed, for all the elements studied except for Fe, between the content bioavailable in the soil and the accumulated in both leaves and grapes (R=0.602-0.775, p<0.01). PMID:27132841

  20. Improving the oral bioavailability of sulpiride by sodium oleate in rabbits.

    Science.gov (United States)

    Naasani, I; Kohri, N; Iseki, K; Miyazaki, K

    1995-06-01

    To improve the limited oral bioavailability of sulpiride, a dosage form containing sodium oleate as an absorption enhancer was developed and evaluated using gastric-emptying-controlled rabbits in a cross-over manner. In addition to the known properties of sodium oleate with respect to modifying the permeability of biomembranes, it was found to be capable of improving the physicochemical properties of sulpiride toward a higher lipophilicity (by ion-pair association) and a higher solubility (by micellar solubilization). Nonetheless, the incorporation of sodium oleate with sulpiride as a mixture filled in hard gelatin capsules failed to increase intestinal absorption, whereas the use of enteric capsules, instead of the hard gelatin capsules resulted in a significant increase (P < 0.05) in the oral bioavailability. PMID:7674129

  1. Preparation and enhancement of oral bioavailability of curcumin using microemulsions vehicle.

    Science.gov (United States)

    Hu, Liandong; Jia, Yanhong; Niu, Feng; Jia, Zheng; Yang, Xun; Jiao, Kuiliang

    2012-07-25

    A new microemulsions system of curcumin (CUR-MEs) was successfully developed to improve the solubility and bioavailability of curcumin. Several formulations of the microemulsions system were prepared and evaluated using different ratios of oils, surfactants, and co-surfactants (S&CoS). The optimal formulation, which consists of Capryol 90 (oil), Cremophor RH40 (surfactant), and Transcutol P aqueous solution (co-surfactant), could enhance the solubility of curcumin up to 32.5 mg/mL. The pharmacokinetic study of microemulsions was performed in rats compared to the corresponding suspension. The stability of microemulsions after dilution was excellence. Microemulsions have significantly increased the C(max) and area under the curve (AUC) in comparison to that in suspension (p microemulsions was 22.6-fold higher than that in suspension. The results indicated that the CUR-MEs could be used as an effective formulation for enhancing the oral bioavailability of curcumin. PMID:22587560

  2. Enhancement of solubility and oral bioavailability of poorly soluble drug Valsartan by novel solid self emulsifying drug delivery system

    Directory of Open Access Journals (Sweden)

    B Usha Sri

    2015-07-01

    Full Text Available The main objective of present work was to prepare a solid SEDDS for enhancement of oral bioavailability of Valsartan, poorly water soluble drug. The solubility of the drug was determined in various vehicles. A pseudo ternary phase diagram was constructed to identify the self-micro emulsification region. Further, the resultant formulations were investigated for clarity, phase separation, globule size, effect of pH and dilutions and freeze-thaw stability. The optimized SMEDDS (F4 formulation of Valsartan contained Capmul MCM (Oil, Kolliphor HS 15 (Surfactant and PEG 400 (Co-surfactant. This optimized formulation was converted in to solid SEDDS by adding required quantity of Neusilin US2 as adsorbing agent used for in vitro dissolution and bioavailability assessment. The oral bioavailability of Valsartan from solid SEDDS was 1.6-fold higher compared to that of Valsartan suspension in rats, suggesting a significant increase (p < 0.05 in oral bioavailability of Valsartan from solid SEDDS.

  3. 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.

  4. Potential for Development of an Escherichia coli—Based Biosensor for Assessing Bioavailable Methionine: A Review

    OpenAIRE

    Vesela I. Chalova; Froelich, Clifford A.; Ricke, Steven C.

    2010-01-01

    Methionine is an essential amino acid for animals and is typically considered one of the first limiting amino acids in animal feed formulations. Methionine deficiency or excess in animal diets can lead to sub-optimal animal performance and increased environmental pollution, which necessitates its accurate quantification and proper dosage in animal rations. Animal bioassays are the current industry standard to quantify methionine bioavailability. However, animal-based assays are not only time ...

  5. Design and optimization of self-nanoemulsifying drug delivery systems for improved bioavailability of cyclovirobuxine D

    OpenAIRE

    Ke, Zhongcheng

    2016-01-01

    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 cyclovirobux...

  6. Systematic Development of Self-Emulsifying Drug Delivery Systems of Atorvastatin with Improved Bioavailability Potential

    OpenAIRE

    Khan, Fariba; Islam, Md Saiful; Roni, Monzurul Amin; Jalil, Reza-Ul

    2012-01-01

    The aim of this study was to prepare and characterize a self-emulsifying drug delivery system (SEDDS) with a high drug load of poorly water-soluble atorvastatin for the enhancement of dissolution and oral bioavailability. Solubility of atorvastatin in oil, surfactant, and cosurfactant was determined. Pseudo-ternary phase diagrams were constructed by the aqueous titration method, and formulations were developed based on the optimum excipient combinations. A high drug load (10% w/w) was achieve...

  7. 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

  8. Design and optimization of self-nanoemulsifying drug delivery systems for improved bioavailability of cyclovirobuxine D

    OpenAIRE

    Ke ZC; Hou XF; Jia XB

    2016-01-01

    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...

  9. Functions of Lipids for Enhancement of Oral Bioavailability of Poorly Water-Soluble Drugs

    OpenAIRE

    Basavaraj K. Nanjwade; Patel, Didhija J.; Udhani, Ritesh A.; Manvi, Fakirappa V.

    2011-01-01

    Lipid-based formulations encompass a diverse group of formulations with very different physical appearance, ranging from simple triglyceride vehicles to more sophisticated formulations such as self-emulsifying drug delivery systems (SEDDS). Lipid-based drug delivery systems may contain a broad range of oils, surfactants, and co-solvents. They represent one of the most popular approaches to overcome the absorption barriers and to improve the bioavailability of poorly water-soluble drugs. Diver...

  10. Comparison of a solid SMEDDS and solid dispersion for enhanced stability and bioavailability of clopidogrel napadisilate.

    Science.gov (United States)

    Kim, Dong Wuk; Kwon, Min Seok; Yousaf, Abid Mehmood; Balakrishnan, Prabagar; Park, Jong Hyuck; Kim, Dong Shik; Lee, Beom-Jin; Park, Young Joon; Yong, Chul Soon; Kim, Jong Oh; Choi, Han-Gon

    2014-12-19

    The intention of this study was to compare the physicochemical properties, stability and bioavailability of a clopidogrel napadisilate (CN)-loaded solid dispersion (SD) and solid self-microemulsifying drug delivery system (solid SMEDDS). SD was prepared by a surface attached method using different ratios of Cremophor RH60 (surfactant) and HPMC (polymer), optimized based on their drug solubility. Liquid SMEDDS was composed of oil (peceol), a surfactant (Cremophor RH60) and a co-surfactant (Transcutol HP). A pseudo-ternary phase diagram was constructed to identify the emulsifying domain, and the optimized liquid SMEDDS was spray dried with an inert solid carrier (silicon dioxide), producing the solid SMEDDS. The physicochemical properties, solubility, dissolution, stability and pharmacokinetics were assessed and compared to clopidogrel napadisilate (CN) and bisulfate (CB) powders. In solid SMEDDS, liquid SMEDDS was absorbed or coated inside the pores of silicon dioxide. In SD, hydrophilic polymer and surfactants were adhered onto drug surface. The drug was in crystalline and molecularly dispersed form in SD and solid SMEDDS, respectively. Solid SMEDDS and SD greatly increased the solubility of CN but gave lower drug solubility compared to CB powder. These preparations significantly improved the dissolution of CN, but the latter more increased than the former. Stability under accelerated condition showed that they were more stable compared to CB powder, and SD was more stable than solid SMEDDS. They significantly increased the oral bioavailability of CN powder. Furthermore, SD showed significantly improved oral bioavailability compared to solid SMEDDS and CB powder. Thus, SD with excellent stability and bioavailability is recommended as an alternative for the clopidogrel-based oral formulation. PMID:25263903

  11. Improvement of Bioavailability of Poorly Soluble Drugs through Self Emulsifying Drug Delivery System

    OpenAIRE

    Sanjay Dey; Sajal Kumar Jha; Jadupati Malakar; Amites Gangopadhyay

    2012-01-01

    Self emulsifying drug delivery system (SEDDS) has received particular attention as a means of improvement of oral bioavailability poorly soluble and absorbed drugs. SEDDS are the mixture of oils,surfactants, and co-surfactants. This becomes emulsify when come in contact with aqueous solution of GIT under the condition of gentle stirring and digestive motility. SEDDS includes various dosage forms like capsule, tablets, beads, microspheres, nanospheres, etc. thus SEDDS could efficiently improve...

  12. Chronic administration of a microencapsulated probiotic enhances the bioavailability of orange juice flavanones in humans.

    Science.gov (United States)

    Pereira-Caro, Gema; Oliver, Christine M; Weerakkody, Rangika; Singh, Tanoj; Conlon, Michael; Borges, Gina; Sanguansri, Luz; Lockett, Trevor; Roberts, Susan A; Crozier, Alan; Augustin, Mary Ann

    2015-07-01

    Orange juice (OJ) flavanones are bioactive polyphenols that are absorbed principally in the large intestine. Ingestion of probiotics has been associated with favorable changes in the colonic microflora. The present study examined the acute and chronic effects of orally administered Bifidobacterium longum R0175 on the colonic microflora and bioavailability of OJ flavanones in healthy volunteers. In an acute study volunteers drank OJ with and without the microencapsulated probiotic, whereas the chronic effects were examined when OJ was consumed after daily supplementation with the probiotic over 4 weeks. Bioavailability, assessed by 0-24h urinary excretion, was similar when OJ was consumed with and without acute probiotic intake. Hesperetin-O-glucuronides, naringenin-O-glucuronides, and hesperetin-3'-O-sulfate were the main urinary flavanone metabolites. The overall urinary excretion of these metabolites after OJ ingestion and acute probiotic intake corresponded to 22% of intake, whereas excretion of key colon-derived phenolic and aromatic acids was equivalent to 21% of the ingested OJ (poly)phenols. Acute OJ consumption after chronic probiotic intake over 4 weeks resulted in the excretion of 27% of flavanone intake, and excretion of selected phenolic acids also increased significantly to 43% of (poly)phenol intake, corresponding to an overall bioavailability of 70%. Neither the probiotic bacterial profiles of stools nor the stool moisture, weight, pH, or levels of short-chain fatty acids and phenols differed significantly between treatments. These findings highlight the positive effect of chronic, but not acute, intake of microencapsulated B. longum R0175 on the bioavailability of OJ flavanones. PMID:25801290

  13. Bioavailability and bioaccumulation as crucial factors linking contamination and ecological status

    Czech Academy of Sciences Publication Activity Database

    van Hattum, B.; Leonards, P.; Kukkonen, J.; Sormunen, A.; Tuikka, A.; van Vliet, S.; Bakker, J.; Smedes, F.; van Noort, P.; Streck, G.; Brack, W.; Bandow, N.; Kocan, A.; Lopez de Alda, M.; Brix, R.; Munoz, I.; de Deckere, E.; Van Liefferinge, C.; Leloup, V.; Jurajda, Pavel; Adámek, Zdeněk; Machala, M.; van Gils, J.; Morales, Y.; de Zwart, D.

    Leipzig : UFZ, 2009. s. 29-30. [MODELKEY - How to assess the impact of key pollutants. 30.11.2009-02.12.2009, Leipzig] Grant ostatní: 6th Framework Programme EC(XE) MODELKEY (511237GOCE) Institutional research plan: CEZ:AV0Z60930519 Keywords : aquatic environment * risk assessment Subject RIV: EH - Ecology, Behaviour http://www.modelkey.ufz.de/data/BertvanHattum_Bioavailability_bioaccumulation11966.pdf

  14. Bioavailability of Mineral Nutrients in Plantain Based Product Enriched With Bambara Groundnut Protein Concentrate

    OpenAIRE

    David B. Kiin-Kabari; Sunday Y. Giami; Boisa Ndokiari

    2015-01-01

    Plantain based products (amala, cookies, bread and cakes) enriched with bambara groundnut protein concentrate were produced. Total minerals content of the products were investigated using the atomic absorption spectrophotometry. A total of six essential minerals: iron, calcium, potassium, phosphorus, magnesium and sodium were determined. The bioavailability of these minerals was studied using pepsin and pancreatin enzymes in-vitro digestion method. The products developed were high in potassiu...

  15. MOBILITY AND BIOAVAILABILITY OF HEAVY METALS AND METALLOIDS IN SOIL ENVIRONMENTS

    OpenAIRE

    A Violante; Cozzolino, V; L Perelomov; A.G Caporale; M Pigna

    2010-01-01

    In soil environments, sorption/desorption reactions as well as chemical complexation with inorganic and organic ligands and redox reactions, both biotic and abiotic, are of great importance in controlling their bioavailability, leaching and toxicity. These reactions are affected by many factors such as pH, nature of the sorbents, presence and concentration of organic and inorganic ligands, including humic and fulvic acid, root exudates, microbial metabolites and nutrients. In this review, we ...

  16. Bioavailability of AREDS1 micronutrients from softgel capsules and tablets: a pilot study

    OpenAIRE

    Johnson, Elizabeth J.; Vishwanathan, Rohini; Rasmussen, Helen M.; Lang, John C.

    2014-01-01

    Purpose The benefits of antioxidant micronutrients in slowing progression to advanced stages of age-related macular degeneration (AMD) was supported by the 4/day tablet form investigated in the Age-related Eye Disease Study 1 (AREDS1) and the 2/day softgel form in the Age-related Eye Disease Study 2 (AREDS2). However, the choices of excipient, dosage form, and ingredient chemistry as well as the patient physiologies and pathologies can influence bioavailability and efficacy. The objective of ...

  17. Are iron nanoparticles a potential source of bioavailable Fe to marine algae?

    Science.gov (United States)

    Shi, Zongbo; Pettitt, Michala

    2015-04-01

    Atmospheric Fe deposition has been suggested to affect biological productivity, not only in the Fe limited High Nutrient Low Chlorophyll (HNLC) regions, but also in the Tropical oligotrophic gyres. Therefore, it has direct and indirect impact on the climate. Atmospheric deposition provides soluble Fe as well as Fe nanoparticles. Our previous study confirmed the presence of Fe nanoparticles in rainwater, while another study by Aguilar-Islas et al. (2010) showed that Fe nanoparticles are the dominant fraction of aerosol derived dissolved Fe. It was generally accepted that soluble Fe is bioavailable. The question is: are Fe nanoparticles potential sources of bioavailable Fe to marine phytoplankton as well? In this study, we synthesized Fe nanoparticles in the laboratory. The Fe nanoparticles were coated with citrate to avoid particle aggregation. The freshly prepared Fe nanoparticles were cultured with Fe depleted Thalassiosira pseudonana diatom cells at a concentration of 10nM to 1000nM Fe. We also cultured the diatom cells with soluble Fe at the same Fe concentration. We found that chlorophyll a content in the Thalassiosira pseudonana diatom cells increase by over 50% and 150% after 4 days of culture with 100 nM and 1000 nM Fe nanoparticles. Surprisingly, soluble Fe at the same concentration had a similar impact on the chlorophyll a content in the Thalassiosira pseudonana diatom cells. This may be due to the fact that soluble Fe precipitated as nanoparticles at a high pH of the culture media (similar to real sea water pH). Similar process may take place during atmospheric deposition of soluble Fe. Our results suggest that both soluble and nanoparticles Fe in atmospheric depositions are potential source of bioavailable Fe to the marine phytoplankton. Further investigations on the bioavailability of soluble and nanoparticle Fe in the rainwater are underway.

  18. Speciation and bioavailability of soil nutrients: effect on crop production and environment

    OpenAIRE

    Maria Martin; Elisabetta Barberis; Luisella Celi

    2009-01-01

    The agricultural production, determining the quality of the foodstuffs, depends on the biological characteristics of the crops and on the environmental properties, where soil environment plays a central role. Crops absorb water and nutritive elements from soil, but they can intake toxic elements as well. The potential benefits, or dangers, due to the presence of a certain element in soil, depend on its chemical speciation regulating its bioavailability, toxicity, environmental mobility, and b...

  19. Interaction between micronutrients, their impact on bioavailability and significance in nutrition intervention. Highlights and achievements

    International Nuclear Information System (INIS)

    Micronutrient deficiencies are of greatest public health significance in Sri Lanka, and as such investigating an effective programme for the prevention is urgently required. Scientific objectives: To study possible interactions between micronutrients (iron and zinc) that may interfere with utilization by a double blind randomized control trial; To determine the bioavailability of iron and zinc using stable isotope methodology; To study iron and zinc status in patients diagnosed as having endemic goitre; To assess the selenium status among the preadolescents

  20. How does curcumin work with poor bioavailability? Clues from experimental and theoretical studies

    OpenAIRE

    Liang Shen; Cui-Cui Liu; Chun-Yan An; Hong-Fang Ji

    2016-01-01

    Curcumin is a natural product with multiple biological activities and numerous potential therapeutic applications. However, its poor systemic bioavailability fails to explain the potent pharmacological effects and hinders its clinical application. Using experimental and theoretical approaches, we compared curcumin and its degradation products for its biological activities against Alzheimer’s disease (AD), including the superoxide anion radical (O2 .–)-scavenging activity, Aβ fibrils (fAβ) for...

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

    OpenAIRE

    Bartolome, N.; Hilber, I.; Schulin, R.; Mayer, Philipp; Bucheli, T.

    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). 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 bioavailabilit...

  2. Oral Bioavailability Enhancement of Exemestane from Self-Microemulsifying Drug Delivery System (SMEDDS)

    OpenAIRE

    Singh, Ajeet K.; Chaurasiya, Akash; Awasthi, Anshumali; Mishra, Gautam; Asati, Dinesh; Khar, Roop K.; Mukherjee, Rama

    2009-01-01

    Limited aqueous solubility of exemestane leads to high variability in absorption after oral administration. To improve the solubility and bioavailability of exemestane, the self-microemulsifying drug delivery system (SMEDDS) was developed. SMEDDS comprises of isotropic mixture of natural or synthetic oil, surfactant, and cosurfactant, which, upon dilution with aqueous media, spontaneously form fine o/w microemulsion with less than 100 nm in droplet size. Solubility of exemestane were determin...

  3. The plasma bioavailability of nitrate and betanin from Beta vulgaris rubra in humans

    OpenAIRE

    Clifford, Tom; Constantinou, Costas; Keane, Karen; West, Dan; Howatson, Glyn; Stevenson, Emma

    2016-01-01

    Purpose To evaluate the plasma bioavailability of betanin and nitric oxide (NOx) after consuming beetroot juice (BTJ) and whole beetroot (BF). BTJ and BF were also analysed for antioxidant capacity, polyphenol content (TPC) and betalain content. Methods Ten healthy males consumed either 250 ml of BTJ, 300 g of BF or a placebo drink, in a randomised, crossover design. Venous plasma samples were collected pre (baseline), 1, 2, 3, 5 and 8 h post-ingestion. Betanin content in BTJ, BF an...

  4. Isotope-aided studies of the bioavailability of iron from Myanmar diets

    International Nuclear Information System (INIS)

    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. Prediction of the bioavailability of minerals and trace elements in foods.

    OpenAIRE

    Wolters, M.G.E.

    1992-01-01

    Minerals and trace elements play essential roles in numerous biochemical and physiological processes in animals and man. A deficiency, an overdose or imbalances between minerals or trace elements will exert a negative effect on health. Generally, it is not the ingested dose of minerals and trace elements that is important to maintain balance, but rather the amount that is bioavailable (available for biological and biochemical processes in the organism). Several food components are able to for...

  6. Comparative human bioavailability study of macrocrystalline nitrofurantoin and two prolonged-action hydroxymethylnitrofurantoin preparations.

    Science.gov (United States)

    Guelen, P J; Boerema, J B; Vree, T B

    1988-12-01

    This single-blind crossover study compared the human bioavailability of macrocrystalline nitrofurantoin (Furadantine MC) and two prolonged-action hydroxymethylnitrofurantoin formulations (Urfadyn PL, bid, and Uridurine, tid), based on plasma nitrofurantoin concentrations and urinary nitrofurantoin excretion. The drugs were administered to 16 healthy females for a single day according to the recommended daily dosages. For comparison, Furadantine MC was administered both at the qid dosage recommended by the manufacturer and at tid dosage. Pharmacokinetic parameters determined were maximum plasma concentration after first dose, minimum plasma concentration after first dose, area under the plasma concentration-time curve (AUC), cumulative renal excretion over 30 hours (ARE), overall renal clearance, total body clearance, and bioavailability relative to Furadantine MC qid, based on plasma AUC (F) and ARE (Fren). F for Furadantine MC 100 mg tid was 108 +/- 25 percent (mean +/- SD); for Uridurine 100 mg tid and Urfadyn PL 100 mg bid, F equalled 86 +/- 33 percent and 53 +/- 20 percent (p less than 0.05), respectively. A similar relationship was observed between Fren for Furadantine MC 100 mg qid and the respective Fren of Furadantine MC 100 mg tid, Uridurine 100 mg tid, and Urfadyn PL 100 mg bid. No significant difference was found between the respective F and Fren of each of the drugs studied. Although bioavailability was comparable for Furadantine MC tid and qid, the single-day design of these studies precludes inferring that these dosage schedules are therapeutically equivalent. However, the significantly lower relative bioavailabilities for the prolonged-action hydroxymethylnitrofurantoin formulations suggest that Urfadyn PL 100 mg bid and Uridurine 100 mg tid are not pharmacokinetically equivalent to Furadantine MC. PMID:3243175

  7. Bioavailability of andrographolide and protection against carbon tetrachloride-induced oxidative damage in rats

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Haw-Wen [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Huang, Chin-Shiu [Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan (China); Li, Chien-Chun [School of Nutrition, Chung Shan Medical University, Taichung, Taiwan (China); Department of Nutrition, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Lin, Ai-Hsuan; Huang, Yu-Ju [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Wang, Tsu-Shing [Department of Biomedical Science, Chung Shan Medical University, Taichung, Taiwan (China); Yao, Hsien-Tsung, E-mail: htyao@mail.cmu.edu.tw [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Lii, Chong-Kuei, E-mail: cklii@mail.cmu.edu.tw [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan (China)

    2014-10-01

    Andrographolide, a bioactive diterpenoid, is identified in Andrographis paniculata. In this study, we investigated the pharmacokinetics and bioavailability of andrographolide in rats and studied whether andrographolide enhances antioxidant defense in a variety of tissues and protects against carbon tetrachloride-induced oxidative damage. After a single 50-mg/kg administration, the maximum plasma concentration of andrographolide was 1 μM which peaked at 30 min. The bioavailability of andrographolide was 1.19%. In a hepatoprotection study, rats were intragastrically dosed with 30 or 50 mg/kg andrographolide for 5 consecutive days. The results showed that andrographolide up-regulated glutamate cysteine ligase (GCL) catalytic and modifier subunits, superoxide dismutase (SOD)-1, heme oxygenase (HO)-1, and glutathione (GSH) S-transferase (GST) Ya/Yb protein and mRNA expression in the liver, heart, and kidneys. The activity of SOD, GST, and GSH reductase was also increased in rats dosed with andrographolide (p < 0.05). Immunoblot analysis and EMSA revealed that andrographolide increased nuclear Nrf2 contents and Nrf2 binding to DNA, respectively. After the 5-day andrographolide treatment, one group of animals was intraperitoneally injected with carbon tetrachloride (CCl{sub 4}) at day 6. Andrographolide pretreatment suppressed CCl{sub 4}-induced plasma aminotransferase activity and hepatic lipid peroxidation (p < 0.05). These results suggest that andrographolide is quickly absorbed in the intestinal tract in rats with a bioavailability of 1.19%. Andrographolide protects against chemical-induced oxidative damage by up-regulating the gene transcription and activity of antioxidant enzymes in various tissues. - Highlights: • The bioavailability of andrographolide is 1.19% in rats. • Plasma concentration reaches 1 μM after giving 50 mg/kg andrographolide. • Andrographolide up-regulates Nrf2-dependent antioxidant genes. • Andrographolide increases antioxidant defense

  8. Bioavailable transition metals in particulate matter mediate cardiopulmonary injury in healthy and compromised animal models.

    OpenAIRE

    Costa, D L; Dreher, K. L.

    1997-01-01

    Many epidemiologic reports associate ambient levels of particulate matter (PM) with human mortality and morbidity, particularly in people with preexisting cardiopulmonary disease (e.g., chronic obstructive pulmonary disease, infection, asthma). Because much ambient PM is derived from combustion sources, we tested the hypothesis that the health effects of PM arise from anthropogenic PM that contains bioavailable transition metals. The PM samples studied derived from three emission sources (two...

  9. Development and characterization of an atorvastatin solid dispersion formulation using skimmed milk for improved oral bioavailability

    OpenAIRE

    Ankush Choudhary; Avtar C. Rana; Geeta Aggarwal; Virender Kumar; Foziyah Zakir

    2012-01-01

    Atorvastatin has low aqueous solubility resulting in low oral bioavailability (12%) and thus presents a challenge in formulating a suitable dosage form. To improve the aqueous solubility, a solid dispersion formulation of atorvastatin was prepared by lyophilization utilising skimmed milk as a carrier. Six different formulations were prepared with varying ratios of drug and carrier and the corresponding physical mixtures were also prepared. The formation of a solid dispersion formulation was c...

  10. PLANTEROSOMES: A POTENTIAL PHYTO-PHOSPHOLIPID CARRIERS FOR THE BIOAVAILABILITY ENHANCEMENT OF HERBAL EXTRACTS

    Directory of Open Access Journals (Sweden)

    Priyanka Rathore

    2012-03-01

    Full Text Available Planterosomes, term “PLANTERO” means plant while “SOME” means cell-like. A novel emerging technique applied to phytopharmaceutical for the enhancement of bioavailability of herbal extract for medicinal applications. Since the two major limiting factors for molecules to pass the biological membrane for their absorption in the blood stream mainly includes lipid solubility and molecular sizes. There are many plant extracts having excellent bioactivity in vitro but low or less in vivo because of their poor lipid solubility and improper size of the molecule or both which result in poor absorption and bioavailability of constituents from plant extract and are destroyed in the gastric fluids when taken orally. Planterosomes are recent advanced forms of herbal formulations that have enhanced absorption rate, producing better bioavailability than conventional herbal extracts. Since they have improved pharmacological and pharmacokinetic parameters, they can be used in the treatment of the acute and chronic liver disease. Planterosomes are prepared by non conventional methods. Planterosomes absorption in GIT is greater resulting in increased plasma level than individual component. They act as a bridge between novel delivery system and conventional delivery system. Phospholipids molecule acting as vital carrier made up of water soluble head and two fat soluble tails, due to this nature they possess dual solubility and thus acting as an effective emulsifier. These drug-phospholipids complex can be formulated in the form of solutions, suspensions, emulsions, syrup, lotion, gel, cream, aqueous microdispersions, pill, capsule, powder, granules and chewable tablets. Planterosomes just like Phytosomes technology effectively enhanced the bioavailability of many popular herbal extracts including milk thistle, Ginkgo biloba, grape seed and ginseng etc.

  11. Sources and fate of bioavailable dissolved organic nitrogen in the Neuse River Estuary, North Carolina

    Science.gov (United States)

    Paerl, H. W.; Peierls, B. L.; Hounshell, A.; Osburn, C. L.

    2015-12-01

    Eutrophication is a widespread problem affecting the structure and function of estuaries and is often linked to anthropogenic nitrogen (N) enrichment, since N is the primary nutrient limiting algal production. Watershed management actions typically have ignored dissolved organic nitrogen (DON) loading because of its perceived refractory nature and instead focused on inorganic N as targets for loading reductions. A fluorescence-based model indicated that anthropogenic sources of DON near the head of the microtidal Neuse River Estuary (NRE), NC were dominated by septic systems and poultry waste. A series of bioassays were used to determine the bioavailability of river DON and DON-rich sources to primary producers and whether those additions promoted the growth of certain phytoplankton taxa, particularly harmful species. Overall, at time scales up to two to three weeks, estuarine phytoplankton and bacteria only showed limited responses to additions of high molecular weight (HMW, >1 kDa) river DON. When increases in productivity and biomass did occur, they were quite small compared with the response to inorganic N. Low molecular weight (LMW) river DON, waste water treatment plant effluent, and poultry litter extract did have a positive effect on phytoplankton and bacterial production, indicating a bioavailable fraction. High variability of bulk DON concentration suggested that bioavailable compounds added in the experimental treatments were low in concentration and turned over quite rapidly. Some phytoplankton taxa, as measured by diagnostic photopigments, appeared to be selectively enhanced by the HMW and specific source DON additions, although the taxa could not be positively identified as harmful species. Preliminary tests show that labile autochthonous organic matter may act as a primer for the mineralization of the HMW DON. These and other, longer-term bioavailability studies will be needed to adequately address the fate of watershed DON in estuarine ecosystems.

  12. Bioavailability Studies of Metals in Surface Water of River Challawa, Nigeria

    OpenAIRE

    Uzairu, A.; O. J. Okunola; Wakawa, R. J.; Adewusi, S. G.

    2014-01-01

    Due to industrialization of Kano City, more industries located within Challawa industrial estate have discharged waste informed of effluents into River Challawa, which is the main source of irrigation water for agricultural land. Hence, this study is aim at assessing the bioavailable fractions of the metals zinc (Zn), lead (Pb), copper (Cu), chromium (Cr) and cadmium (Cd) in surface water of river Challawa, Kano, Nigeria, across seasons. It was found that the concentrations of most metals inc...

  13. Simvastatin-loaded PLGA nanoparticles for improved oral bioavailability and sustained release: Effect of formulation variables

    OpenAIRE

    Aman Soni; Anand Gadad; Panchaxari Dandagi; Vinayak Mastiholimath

    2011-01-01

    The objective of this study was to prepare a nanoparticulate formulation of simvastatin (SV) for improving oral bioavailability and sustaining the drug release while investigating the effect of various formulation parameters on characteristics of nanoparticles. Nanoparticles containing SV were prepared by a modified emulsification solvent evaporation technique using a biodegradable polymer, poly(d,l-lactide-coglycolide) (PLGA) as a sustained release carrier. The effect of various formulation ...

  14. Bioavailability and absorption kinetics of nicotine following application of a transdermal system.

    OpenAIRE

    Gupta, S.K.; Benowitz, N L; Jacob, P.; Rolf, C N; Gorsline, J

    1993-01-01

    1. The absolute bioavailability and absorption kinetics of nicotine were investigated in 13 healthy adult male smokers following single and multiple applications of a nicotine transdermal system (NTS), designed to release nicotine at an approximate rate of 1.5 mg h-1 over 24 h. The absorption of nicotine from the single NTS application was calculated with reference to a simultaneous intravenous infusion (i.v.) of deuterium-labelled nicotine. 2. The mean input time (MIT) and mean absorption ti...

  15. Development of an integrated in vitro model for the prediction of oral bioavailability of nanoparticles

    OpenAIRE

    Walczak, A.P.

    2014-01-01

    Title of the PhD thesis: Development of an integrated in vitro model for the prediction of oral bioavailability of nanoparticles The number of food-related products containing nanoparticles (NPs) increases. To understand the safety of such products, the potential uptake of these NPs following consumption needs to be assessed. In normal safety assessment studies this is investigated using animal models. For scientific, ethical and economical reasons, there is a demand to refine, reduce and rep...

  16. Factors regulating the bioavailability of methylmercury to breeding rusty blackbirds in northeastern wetlands

    International Nuclear Information System (INIS)

    Rusty blackbirds are undergoing rapid population decline and have elevated Hg concentrations while breeding in the Acadian ecoregion of North America. Factors regulating the bioavailability of methyl-Hg (MeHg) within this population's habitat were determined using water, invertebrates, and blood from adult rusty blackbirds collected for Hg-speciation, along with additional water column parameters: MeHg and THg, dissolved organic carbon, pH, dissolved oxygen, conductivity, redox potential, and temperature. Both DO2 and pH were negatively related to biota MeHg, while water MeHg concentrations were positively related. Both invertebrate MeHg concentration and %MeHg increased with trophic level. Invertebrate MeHg concentrations were among the greatest reported when compared with those reported elsewhere for wetlands and waterbodies—often several times greater for similar taxa—while percent MeHg of THg were similar. An environment with high bioavailability of MeHg in combination with a high trophic position best explains elevated Hg concentrations for this species regional population. - Highlights: ► DO2 and pH negatively correlate with wetland biota methylmercury. ► Water MeHg concentrations positively correlate with wetland biota methylmercury. ► Rusty blackbird blood-Hg correlates with MeHg in Araneae, Ephemeroptera, and Trichoptera, but not Odonata. ► Habitat with high MeHg bioavailability and a high trophic position explains regionally elevated Hg in the rusty blackbird. - Elevated mercury concentrations in the disappearing Acadian population of breeding rusty blackbirds are due to a diet of aquatic macroinvertebrates in an environment with high methylmercury bioavailability.

  17. Carbon Dioxide-Mediated Generation of Hybrid Nanoparticles for Improved Bioavailability of Protein Kinase Inhibitors

    OpenAIRE

    Jesson, Gérald; Brisander, Magnus; Andersson, Per; Demirbüker, Mustafa; Derand, Helene; Lennernäs, Hans; Malmsten, Martin

    2013-01-01

    ABSTRACT Purpose A versatile methodology is demonstrated for improving dissolution kinetics, gastrointestinal (GI) absorption, and bioavailability of protein kinase inhibitors (PKIs). Methods The approach is based on nanoparticle precipitation by sub- or supercritical CO2 together with a matrix-forming polymer, incorporating surfactants either during or after nanoparticle formation. Notably, striking synergistic effects between hybrid PKI/polymer nanoparticles and surfactant added after parti...

  18. Recent Advances in Omega-3: Health Benefits, Sources, Products and Bioavailability

    OpenAIRE

    Nichols, Peter D.; Alexandra McManus; Kevin Krail; Andrew J. Sinclair; Matt Miller

    2014-01-01

    The joint symposium of The Omega-3 Centre and the Australasian Section American Oil Chemists Society; Recent Advances in Omega-3: Health Benefits, Sources, Products and Bioavailability, was held November 7, 2013 in Newcastle, NSW, Australia. Over 115 attendees received new information on a range of health benefits, aquaculture as a sustainable source of supply, and current and potential new and novel sources of these essential omega-3 long-chain (LC, ≥C20) polyunsaturated fatty acid nutrients...

  19. Bioavailability assessment of metals chelated as proteinates using the Ussing Chamber Model

    OpenAIRE

    Piva, G.; G. Cavanna; G. Casadei; A. Piva

    2011-01-01

    Preparation of proteinates by hydrolysis of organic matter produces a blend of different proteins, and may likely result in the chelation of trace elements. Often this process results in an increased bioavailability of minerals, leading to a higher absorption rate than inorganic salts (Cao et al., 2000; Uchida et al., 2001; Bailey et al., 2001; Guo et al., 2001). Usually trace elements uptake takes place along the small intestine, mainly jejunum (Tapia et al., 1996; Arredondo et al., 2000), e...

  20. Enhanced bioavailability of apigenin via preparation of a carbon nanopowder solid dispersion

    Directory of Open Access Journals (Sweden)

    Ding SM

    2014-05-01

    Full Text Available Shu-min Ding,1–3 Zhen-hai Zhang,1,3 Jie Song,1,3 Xu-dong Cheng,1,3 Jun Jiang,1,3 Xiao-bin Jia1,31Affiliated Hospital on Integration of Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China; 2School of Pharmaceutical Engineering and Life Science, Changzhou University, Changzhou, People's Republic of China; 3Key Laboratory of New Drug Delivery System of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, Nanjing, People's Republic of ChinaAbstract: In this study, a novel carbon nanopowder (CNP drug carrier was developed to improve the oral bioavailability of apigenin (AP. Solid dispersions (SDs of AP with CNP were prepared, and their in vitro drug release and in vivo performance were evaluated. The physicochemical properties of the formulations were examined by differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy. Drug release profiles showed that AP dissolution from the CNP-AP system (weight ratio, 6:1 after 60 minutes improved by 275% compared with that of pure AP. Moreover, the pharmacokinetic analysis of SD formulations in rats showed that the AP area under the curve0–t value was 1.83 times higher for the CNP-AP system than for pure AP, indicating that its bioavailability was significantly improved. In addition, compared with pure AP, SDs had a significantly higher peak and shorter time to peak. Preliminary intestinal toxicity tests indicated that there was no significant difference in the tissues of the rats treated with the CNP-AP system, rats treated with the CNP alone, and controls. In conclusion, CNP-based SDs could be used for enhancing the bioavailability of poorly water-soluble drugs while also improving drug safety.Keywords: apigenin, carbon nanopowder, solid dispersions, dissolution, oral bioavailability

  1. Enhancement of oral bioavailability of cyclosporine A: comparison of various nanoscale drug-delivery systems.

    Science.gov (United States)

    Wang, Kai; Qi, Jianping; Weng, Tengfei; Tian, Zhiqiang; Lu, Yi; Hu, Kaili; Yin, Zongning; Wu, Wei

    2014-01-01

    A variety of nanoscale delivery systems have been shown to enhance the oral absorption of poorly water-soluble and poorly permeable drugs. However, the performance of these systems has seldom been evaluated simultaneously. The aim of this study was to compare the bioavailability enhancement effect of lipid-based nanocarriers with poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) to highlight the importance of the lipid composition, with cyclosporine A (CyA) as a model drug. CyA-loaded PLGA NPs, nanostructured lipid carriers (NLCs), and self-microemulsifying drug-delivery systems (SMEDDS) were prepared. The particle size of PLGA NPs (182.2 ± 12.8 nm) was larger than that of NLCs (89.7 ± 9.0 nm) and SMEDDS (26.9 ± 1.9 nm). All vehicles are charged negatively. The entrapment efficiency of PLGA NPs and NLCs was 87.6%± 1.6% and 80.3%± 0.6%, respectively. In vitro release tests indicated that the cumulative release of CyA was lower than 4% from all vehicles, including Sandimmun Neoral(®), according to the dialysis method. Both NLCs and SMEDDS showed high relative oral bioavailability, 111.8% and 73.6%, respectively, after oral gavage administration to beagle dogs, which was not statistically different from commercial Sandimmun Neoral(®). However, PLGA NPs failed to achieve efficient absorption, with relative bioavailability of about 22.7%. It is concluded that lipid-based nanoscale drug-delivery systems are superior to polymeric NPs in enhancing oral bioavailability of poorly water-soluble and poorly permeable drugs. PMID:25378925

  2. Assessment of polymorphic metabolite data in bioavailability/bioequivalence studies - considerations and challenges

    OpenAIRE

    Nuggehally R Srinivas

    2011-01-01

    Bioavailability (BA)/ bioequivalence (BE) studies are the cornerstone for the approval of generic drugs. While BA/BE assessment involving the pharmacokinetic data of the parent compound has been routinely performed, the introduction of the assessment of metabolite(s) data, alone or in addition to parent compound, has also emerged. In this context, the assessment of BA/BE of metabolite(s) may pose additional complexities and challenges, if the metabolic pathway is under the influence of a poly...

  3. Role of herbal bioactives as a potential bioavailability enhancer for Active Pharmaceutical Ingredients.

    Science.gov (United States)

    Ajazuddin; Alexander, Amit; Qureshi, Azra; Kumari, Leena; Vaishnav, Pramudita; Sharma, Mukesh; Saraf, Swarnlata; Saraf, Shailendra

    2014-09-01

    The current review emphasizes on the herbal bioenhancers which themselves do not possess inherent pharmacological activity of their own but when co-administered with Active Pharmaceutical Ingredients (API), enhances their bioavailability and efficacy. Herbal bioenhancers play a crucial role in enhancing the bioavailability and bioefficacy of different classes of drugs, such as antihypertensives, anticancer, antiviral, antitubercular and antifungal drugs at low doses. This paper highlights various natural compounds that can be utilized as an efficient bioenhancer. Several herbal compounds including piperine, quercetin, genistein, naringin, sinomenine, curcumin, and glycyrrhizin have demonstrated capability to improve the pharmacokinetic parameters of several potent API. This article also focuses on various United States patents on herbal bioenhancers, which has proved to be beneficial in improving oral absorption of nutraceuticals like vitamins, minerals, amino acids and certain herbal compounds. The present paper also describes proposed mechanism of action, which mainly includes absorption process, drug metabolism, and action on drug target. The herbal bioenhancers are easily available, safe, free from side effects, minimizes drug toxicity, shortens the duration of treatment, lowers the drug resistance problems and minimizes the cost of treatment. Inspite of the fact that herbal bioenhancers provide an innovative concept for enhancing the bioavailability of several potent drugs, there are numerous bioenhancers of herbal origin that are yet to be explored in several vital areas. These bioenhancers must also be implied to enhance the bioavailability and bioefficacy through routes other than the oral route of drug delivery. There is a vast array of unexploited plants which can be investigated for their drug bioenhancing potency. The toxicity profiles of these herbal bioenhancers must not be overlooked. Researches must be carried out to solve these issues and to

  4. The effect of food and concurrent chemotherapy on the bioavailability of oral etoposide.

    OpenAIRE

    Harvey, V. J.; Slevin, M L; Joel, S P; Johnston, A.; Wrigley, P F

    1985-01-01

    There is no information on the effect of food or concurrent drug administration on the bioavailability of oral etoposide, despite the fact that treatment is frequently administered over several days and most often in combination with other cytotoxic agents. The influence of these factors has been studied in 11 patients, receiving combination cytotoxic therapy for extensive small cell lung carcinoma. Neither food nor concurrent oral or intravenous chemotherapy had a significant effect on the m...

  5. 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

  6. [Distribution and bioavailability of nitrogen and phosphorus species in the urban dusts from Hefei City].

    Science.gov (United States)

    Li, Ru-Zhong; Zhou, Ai-Jia; Tong, Fang; Li, Feng; Qian, Jia-Zhong

    2012-04-01

    To find out the distribution and bioavailability of nitrogen (N) and phosphorus (P) species in the urban dusts of Hefei City, 52 samples were collected from impervious areas with six different urban land-use types. The contents of ammonia nitrogen (NH4(+) -N), nitrate nitrogen (NO3(-) -N), exchangeable P (Ex-P), Al-bound P (Al-P), Fe-bound P (Fe-P), occluded P (Oc-P), Ca-bound P (Ca-P), detrital apatite P (De-P), organic P (Or-P) as well as total nitrogen (TN) and total phosphorus (TP) were measured by sequential extraction methods. The studies on spatial distribution, correlation and bioavailability of nitrogen and phosphorus species were made according to the analyzed data. The results show that the TN is composed mainly of organic nitrogen (Or-N) while the TP consists chiefly of inorganic phosphorus (IP) in the urban dusts of Hefei City, and the spatial variability of nitrogen and phosphorus species contents are greatly affected by the mode of urban land-use type. In addition, there are significant correlations among partial nitrogen and phosphorus forms in dusts. Corresponding to different urban land-use types such as industrial area, commercial area, residential area, educational area, traffic area and public landscapes and city squares, the average ratios of bioavailable nitrogen content (the sum of NH4(+) -N and NO3(-) -N) to TN are 8.87%, 9.60%, 6.68%, 9.37%, 8.20% and 8.17%, respectively, while the mean ratios of bioavailable phosphorus content (the sum of Ex-P, Al-P and Fe-P) to TP, are equal to 6.70%, 18.19%, 10.10%, 9.69%, 10.64% and 14.03%, respectively. PMID:22720560

  7. Nanotechnology: an effective tool for enhancing bioavailability and bioactivity of phytomedicine

    OpenAIRE

    Gunasekaran, Thirumurugan; Haile, Tedesse; Nigusse, Tedele; Dhanaraju, Magharla Dasaratha

    2014-01-01

    To achieve the desired therapeutic objective, the drug product must deliver the active drug at an optimal rate and amount. By proper biopharmaceutic design, the rate and extent of drug absorption (also called as bioavailability) or the systemic delivery of drugs to the body can be varied from rapid and complete absorption to slow and sustained absorption depending upon the desired therapeutic objective. Phytomedicine have served as the foundation for a larger fraction of the current pharmacop...

  8. Bioavailability and potential carcinogenicity of polycyclic aromatic hydrocarbons from wood combustion particulate matter in vitro.

    Science.gov (United States)

    Gauggel-Lewandowski, Susanne; Heussner, Alexandra H; Steinberg, Pablo; Pieterse, Bart; van der Burg, Bart; Dietrich, Daniel R

    2013-11-25

    Due to increasing energy demand and limited fossil fuels, renewable energy sources have gained in importance. Particulate matter (PM) in general, but also PM from the combustion of wood is known to exert adverse health effects in human. These are often related to specific toxic compounds adsorbed to the PM surface, such as polycyclic aromatic hydrocarbons (PAH), of which some are known human carcinogens. This study focused on the bioavailability of PAHs and on the tumor initiation potential of wood combustion PM, using the PAH CALUX® reporter gene assay and the BALB/c 3T3 cell transformation assay, respectively. For this, both cell assays were exposed to PM and their respective organic extracts from varying degrees of combustion. The PAH CALUX® experiments demonstrated a concentration-response relationship matching the PAHs detected in the samples. Contrary to expectations, PM samples from complete (CC) and incomplete combustion (IC) provided for a stronger and weaker response, respectively, suggesting that PAH were more readily bioavailable in PM from CC. These findings were corroborated via PAH spiking experiments indicating that IC PM contains organic components that strongly adsorb PAH thereby reducing their bioavailability. The results obtained with organic extracts in the cell transformation assay presented the highest potential for carcinogenicity in samples with high PAH contents, albeit PM from CC also demonstrated a carcinogenic potential. In conclusion, the in vitro assays employed emphasize that CC produces PM with low PAH content however with a general higher bioavailability and thus with a nearly similar carcinogenic potential than IC PM. PMID:23796820

  9. DETERMINATION OF MOBILITY AND BIOAVAILABILITY OF HEAVY METALS IN THE URBAN AIR PARTICULATES MATTER OF ISFAHAN

    OpenAIRE

    Kalantari, A.; M. Talebi; B BINA

    2001-01-01

    Introduction: In addition to, Carbohyrates, Lipids, Amino acids and vitamins, some of the trace metals are known vital for biological activity. But some of them not only are not necessary, but also they are very toxic and carcinogen. In this research the rate of Mobility and Bioavailability of heavy metals associated with airborne particulates matter such as Zn, Pb, Cd, Cu, Fe, Ni and Cr have been measured. Methods: The sequential extraction has been used for releasing of heavy metales f...

  10. Arsenic in marine sediments from French Mediterranean ports: Geochemical partitioning, bioavailability and ecotoxicology

    OpenAIRE

    Mamindy-Pajany, Yannick; Hurel, Charlotte; Geret, Florence; Galgani, Francois; Battaglia-Brunet, Fabienne; Marmier, Nicolas; Romeo, Michele

    2013-01-01

    This work investigates arsenic mobility, bioavailability and toxicity in marine port sediments using chemical sequential extraction and laboratory toxicity tests. Sediment samples were collected from two different Mediterranean ports, one highly polluted with arsenic and other inorganic and organic pollutants (Estaque port (EST)), and the other one, less polluted, with a low arsenic content (Saint Mandrier port (SM)). Arsenic distribution in the solid phase was studied using a sequential extr...

  11. Lower zinc bioavailability may be related to higher risk of subclinical atherosclerosis in Korean adults.

    Directory of Open Access Journals (Sweden)

    Su Kyoung Jung

    Full Text Available BACKGROUND: There is a proposed link between dietary zinc intake and atherosclerosis, but this relationship remains unclear. Phytate may contribute to this relationship by influencing zinc bioavailability. OBJECTIVE: The aim of this study is to examine the relationship between zinc bioavailability and subclinical atherosclerosis in healthy Korean adults. MATERIALS AND METHODS: The present cross-sectional analysis used baseline data from the Korean multi-Rural Communities Cohort Study (MRCohort, which is a part of The Korean Genome Epidemiology Study (KoGES. A total of 5,532 subjects (2,116 men and 3,416 women aged 40 years and older were recruited from rural communities in South Korea between 2005 and 2010. Phytate:zinc molar ratio, estimated from a food-based food frequency questionnaire (FFQ of 106 food items, was used to determine zinc bioavailability, and carotid intima media thickness (cIMT and pulse wave velocity (PWV were measured to calculate the subclinical atherosclerotic index. RESULTS: We found that phytate:zinc molar ratio is positively related to cIMT in men. A higher phytate:zinc molar ratio was significantly related to an increased risk of atherosclerosis in men, defined as the 80(th percentile value of cIMT (5(th vs. 1(st quintile, OR = 2.11, 95% CI 1.42-3.15, P for trend = 0.0009, and especially in elderly men (5(th vs. 1(st quintile, OR = 2.58, 95% CI 1.52-4.37, P for trend = 0.0021. We found a positive relationship between phytate:zinc molar ratio and atherosclerosis risk among women aged 65 years or younger. Phytate:zinc molar ratio was not found to be related to PWV. CONCLUSIONS: Lower zinc bioavailability may be related to higher atherosclerosis risk.

  12. Bioavailability of andrographolide and protection against carbon tetrachloride-induced oxidative damage in rats

    International Nuclear Information System (INIS)

    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 (CCl4) at day 6. Andrographolide pretreatment suppressed CCl4-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 various

  13. Selenium bioavailability from naturally produced high-selenium peas and oats in selenium-deficient rats.

    Science.gov (United States)

    Yan, Lin; Johnson, LuAnn K

    2011-06-01

    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. PMID:21553810

  14. Oxygen bioavailability and haemoglobins in the brine shrimp Artemia franciscana

    OpenAIRE

    Wachter, B; Blust, R.; Decleir, W.

    1992-01-01

    Bioavailability of oxygen for the saline-water invertebrate Artemia franciscana was studied, since both oxygen concentration and oxygen diffusion rate change with salinity. Total haemoglobin concentration and the relative contribution of each of three haemoglobins was measured in specimens acclimated to different salinities and oxygen concentrations. Both haemoglobin concentration and contribution were influenced by salinity and the group observed (males, females with and females without eggs...

  15. 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 ...

  16. Speciation and Bioavailability Measurements of Environmental Plutonium Using Diffusion in Thin Films

    OpenAIRE

    Cusnir R.; Steinmann P.; Christl M.; Bochud F.; Froidevaux P.

    2015-01-01

    The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can potentially contribute to the exposure of biota and humans. The diffusive gradients in thin films technique is introduced here for in-situ measurements of Pu bioavailability and speciation. A diffusion cell constructed for laboratory experiments with Pu and the newly developed protocol make it possible to simulate the environmental behavior...

  17. The Role of Dietary Fiber in the Bioaccessibility and Bioavailability of Fruit and Vegetable Antioxidants

    OpenAIRE

    Palafox-Carlos, Hugo; Ayala-Zavala, Jesús Fernando; Gustavo A. González-Aguilar

    2011-01-01

    Antioxidants are abundant compounds primarily found in fresh fruits and vegetables, and evidence for their role in the prevention of degenerative diseases is continuously emerging. However, the bioaccessibility and bioavailability of each compound differs greatly, and the most abundant antioxidants in ingested fruit are not necessarily those leading to the highest concentrations of active metabolites in target tissues. Fruit antioxidants are commonly mixed with different macromolecules such a...

  18. A comprehensive model for chemical bioavailability and toxicity of organic chemicals based on first principles

    OpenAIRE

    Forrest, Jay; Bazylewski, Paul; Bauer, Robert; Hong, Seongjin; Kim, Chang Yong; Giesy, John P; Khim, Jong Seong; Chang, Gap Soo

    2014-01-01

    Here, we present a novel model to predict the toxicity and bioavailability of polychlorinated biphenyls (PCBs) as model compounds based on a first principles approach targeting basic electronic characteristics. The predictive model is based on an initio density functional theory. The model suggests HOMO-LUMO energy gap as the overarching indicator of PCBs toxicity, which was shown to be the primary factor predicting toxicity, but not the only factor. The model clearly explains why chlorinatio...

  19. Site-specific sediment characteristics impact on metal bioavailability and bioaccumulation in the Polychaete Nereis virens

    OpenAIRE

    Pini, Jennifer; Richir, Jonathan; Watson, Gordon

    2014-01-01

    The king ragworm (Nereis virens) is a cosmopolitan species of soft sediment inter-tidal communities and is known to be impacted by various pollutants. More precisely, in many coastal locations, N. virens is exposed to a range of metals including copper and zinc which are known to be highly toxic. However, the relationships between metal bioavailable concentrations in the sediment, the pore water and the tissues of N. virens have not yet been investigated in this is ecologically and commercial...

  20. Particle affinity and bioavailability of PAHs associated with coal tar pitch

    OpenAIRE

    Ruus, A.; Bøyum, O.; Grung, M.; Næs, K.

    2007-01-01

    This project has investigated the particle affinity and bioavailability of coal tar pitch related PAHs from sediments outside several Nordic aluminium smelters using the Søderberg technology. Passive samplers (POM) have been used for assessing water-sediment partitioning for PAHs and actual bioaccumulation has been addressed in an experimental setup.The results showed that the PAHs associated with the sediments in the vicinity of the smelters were stronger (a median factor of at least a magni...

  1. 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.

  2. A carnosine intervention study in overweight human volunteers: bioavailability and reactive carbonyl species sequestering effect

    OpenAIRE

    Luca Regazzoni; Barbora de Courten; Davide Garzon; Alessandra Altomare; Cristina Marinello; Michaela Jakubova; Silvia Vallova; Patrik Krumpolec; Marina Carini; Jozef Ukropec; Barbara Ukropcova; Giancarlo Aldini

    2016-01-01

    Carnosine is a natural dipeptide able to react with reactive carbonyl species, which have been recently associated with the onset and progression of several human diseases. Herein, we report an intervention study in overweight individuals. Carnosine (2 g/day) was orally administered for twelve weeks in order to evaluate its bioavailability and metabolic fate. Two carnosine adducts were detected in the urine samples of all subjects. Such adducts are generated from a reaction with acrolein, whi...

  3. The influence of chronic administration of calcium carbonate on the bioavailability of oral ciprofloxacin.

    OpenAIRE

    Sahai, J; Healy, D P; Stotka, J; Polk, R E

    1993-01-01

    Six healthy male volunteers participated in a two-period, two-treatment study to determine the effect of chronic calcium carbonate administration on ciprofloxacin bioavailability. There was a mean reduction of 40% in Cmax and 43% in AUC when calcium carbonate was administered with ciprofloxacin, compared with ciprofloxacin alone (P < 0.05). There were no changes in either half-life or tmax. It is therefore recommended that patients being treated with ciprofloxacin for serious infections refra...

  4. Application of dermal microdialysis for the determination of bioavailability of clobetasol propionate applied to the skin of human subjects

    DEFF Research Database (Denmark)

    Au, W L; Skinner, M F; Benfeldt, E;

    2012-01-01

    Dermal microdialysis was used to assess the bioavailability of a topical corticosteroid, clobetasol propionate, following application onto the skin of human subjects. The penetration of clobetasol propionate from a 4% m/v ethanolic solution applied onto 4 sites on one forearm of healthy human...... drug of interest. Furthermore, the study clearly demonstrated the application of dermal microdialysis as a valuable tool to assess the bioavailability/bioequivalence of clobetasol propionate penetration into the skin following topical application....

  5. Dynamics of Fluoride Bioavailability in the Biofilms of Different Oral Surfaces after Amine Fluoride and Sodium Fluoride Application

    OpenAIRE

    Naumova, Ella A; Christoph Dickten; Rico Jung; Florian Krauss; Henrik Rübesamen; Katharina Schmütsch; Tudor Sandulescu; Stefan Zimmer; Arnold, Wolfgang H.

    2016-01-01

    It was the aim of this study to investigate differences in fluoride bioavailability in different oral areas after the application of amine fluoride (AmF) and sodium fluoride (NaF). The null hypothesis suggested no differences in the fluoride bioavailability. The tongue coating was removed and biofilm samples from the palate, oral floor and cheeks were collected. All subjects brushed their teeth with toothpaste containing AmF or NaF. Specimens were collected before, as well as immediately afte...

  6. Bioequivalence and Bioavailability Clinical Trials: A Status Report from the National Institutes of Health ClinicalTrials.gov Registry

    OpenAIRE

    Stockmann, Chris; Spigarelli, Michael G.; Ampofo, Krow; Sherwin, Catherine MT

    2013-01-01

    Drug development is an expensive process that is marked by a high-failure rate. For this reason early stage bioequivalence and pharmacokinetic studies are essential in determining the fate of new drug products. In this study, we sought to systematically assess the current trends of ongoing and recently completed bioequivalence and bioavailability trials that have been registered within a national clinical trials registry. All bioequivalence and bioavailability studies registered in the United...

  7. Modulation of chelating factors, trace minerals and their estimated bioavailability in Italian and African sorghum (Sorghum bicolor (L.) Moench) porridges

    OpenAIRE

    Proietti, I.; Mantovani, A.; Mouquet Rivier, Claire; Guyot, Jean-Pierre

    2013-01-01

    Factors able to modulate chelating factors, trace minerals and their bioavailability were investigated in porridges of five sorghum (Sorghum bicolor (L.) Moench) varieties: from Nigeria, Senegal, Burkina Faso and two from Italy. Effects of variety and traditional fermentation and cooking were assessed on iron-binding phenolic groups, phytates and iron and zinc content and bioavailability. Chelating factors, trace elements as well as the effect of processing (mainly fermentation) were modulate...

  8. Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics

    OpenAIRE

    Ueda, Yukari; Taira, Zenei

    2013-01-01

    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 mg/kg, and is not affected by anions. Results after oral calcium administration of 150 mg/kg showed that the intes...

  9. Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics

    OpenAIRE

    Zenei Taira, Zenei

    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. Iron, zinc and phytic acid in rice from China: wet and dry processing towards improved mineral bioavailability

    OpenAIRE

    Liang, J.

    2007-01-01

    Rice and rice products supply two thirds of Chinese people with their staple food. Mineral deficiencies, especially of iron and zinc, are prevalent in China, and are caused by insufficient intake and poor bioavailability. Rice and rice products contribute more than 50% of the antinutrient  phytic acid consumed in the average diet, which has a significant negative impact on mineral bioavailability. This thesis reports studies of dry and wet rice processing methods on levels and in vitro solubi...

  11. Determination of activable isotopic tracers of zinc by neutron activation analysis for study of bioavailability of zinc

    International Nuclear Information System (INIS)

    A procedure of pre-irradiation concentration of zinc in fecal samples using anion exchanger was developed for the study of the bioavailability of zinc by neutron activation analysis. The mass ratios between 70Zn and 68Zn, or 64Zn and their contents between natural zinc and enriched zinc are used to calculate the bioavailability of zinc when the abundance of the isotope 70Zn is not high enough. (author) 9 refs.; 1 fig.; 2 tabs

  12. Evidence of reduced oral bioavailability of paracetamol in rats following multiple ingestion of grapefruit juice.

    Science.gov (United States)

    Qinna, Nidal A; Ismail, Obbei A; Alhussainy, Tawfiq M; Idkaidek, Nasir M; Arafat, Tawfiq A

    2016-04-01

    The aim of the current investigation was to assess the ability GFJ to modulate the pharmacokinetic profile of paracetamol following single or repeated administrations of GFJ in Sprague-Dawley rats. Diclofenac and carbamazepine were both used as positive controls. Rats received single GFJ or single distilled water doses or pretreated with three doses of GFJ prior to test drug administration. Blood samples were collected, processed and analyzed using validated HPLC methods, and pharmacokinetic data were constructed for each group. Increase in the bioavailability of both diclofenac and carbamazepine following multiple GFJ ingestion was revealed. Conversely, the bioavailability of paracetamol was significantly reduced following multiple GFJ administration. The percentage of reduction in the C max and AUC of paracetamol were calculated as 31 and 51 %, respectively, compared to none-GFJ-treated control (P < 0.05). The T max was not essentially changed. In conclusion, frequent administration of GFJ was confirmed to modulate the pharmacokinetics of paracetamol in rats by reducing its bioavailability. Meanwhile, it may be advisable not to ingest large amounts of GFJ along with paracetamol to avoid a possible potential loss of the efficacy. PMID:25547640

  13. Bioavailability and bioaccessibility of arsenic in a soil amended with drinking-water treatment residuals.

    Science.gov (United States)

    Nagar, Rachana; Sarkar, Dibyendu; Makris, Konstantinos C; Datta, Rupali; Sylvia, Victor L

    2009-11-01

    Earlier incubation and greenhouse studies in our laboratory confirmed the effectiveness of drinking-water treatment residual (WTR) in decreasing soil arsenic (As) bioaccessibility as determined with in vitro tests, which led us to hypothesize a similar outcome if animal studies were to be conducted. Our objective was to evaluate the potential of WTR in lowering soil As bioavailability by conducting in vivo experiments and compare the in vitro to the in vivo As data. This study was performed using 6-week-old male BALB/c mice that were fed with an As-contaminated soil slurry using the gavage method. Blood and stomach contents were collected at 1 and 24 h after feeding. Urine and excreta were collected at time 0 (before feeding) and 24 h after feeding. Relative As bioavailability (RBA) values calculated from the blood samples of mice fed with WTR and WTR-amended soil samples ranged from 13% to 24% and from 25% to 29%, respectively; both were significantly (p intramuscular administrations was 63-80%. Results illustrate the effectiveness of in situ WTR amendment in decreasing in vivo soil As bioavailability, thereby lowering the potential cancer risk via an oral ingestion pathway. PMID:19347240

  14. Improvement of Bioavailability of Poorly Soluble Drugs through Self Emulsifying Drug Delivery System

    Directory of Open Access Journals (Sweden)

    Sanjay Dey*

    2012-01-01

    Full Text Available Self emulsifying drug delivery system (SEDDS has received particular attention as a means of improvement of oral bioavailability poorly soluble and absorbed drugs. SEDDS are the mixture of oils,surfactants, and co-surfactants. This becomes emulsify when come in contact with aqueous solution of GIT under the condition of gentle stirring and digestive motility. SEDDS includes various dosage forms like capsule, tablets, beads, microspheres, nanospheres, etc. thus SEDDS could efficiently improve oral absorption of the sparingly soluble drugs by self-emulsification. For the improvement of bio-availability of drugs with such properties presents one of the greatest challenges in drug formulations. Various technological strategies are reported in the literature including cyclodextrines complex formation, solid dispersions, or micronization, and different technologies of drug delivery systems. Including these approaches self-emulsifying drug delivery system (SEDDS has gained more attention for enhancement of oral bio-availability with reduction in dose. SEDDS are isotropic mixtures of oil, surfactants, solvents and cosolvents/surfactants. For lipophilic drugs, which have dissolution rate-limited absorption, SEDDS may be a promising strategy to improve the rate and extent of oral absorption.

  15. Bioavailability of bound residues of [14C]febantel to rats

    International Nuclear Information System (INIS)

    The presence of pesticide and drug residues in crops and livestock is a major consideration in the regulation of pesticide and veterinary drug use in the agricultural industry. Furthermore, these is increasing interest in determining the toxicological significance of residues present in food, especially those which remain bound following traditional extraction techniques. Treatment of cattle with Febantel ([N'-N double-prime-bis-methoxycarbonyl-guanidino-3-methoxy-acetamido, 5-phenylthio, benzene]), an anthelmintic, results in residues, a portion of which remain bound following extraction of liver with water and ethyl acetate. We have examined the bioavailability of these bound residues in beef liver excised 7 days after oral administration of [14C]Febantel. No radiocarbon was detected in bile, urine of any of the tissues, however 99.9% of the administered dose was eliminated in the feces indicating 0% bioavailability. For comparison, beef liver was identically extracted then fortified with [14C]Febantel prior to administration to cannulated rats. In this case the bile and urine contained 31.4 and 51.9% of the dose respectively, whereas the feces contained 11.5% and the gastrointestinal tract and remaining tissues accounted for 2.4%. Therefore, Febantel administered in this manner is 85.7% bioavailable. These findings strongly suggest that though Febantel is readily absorbed, bound residues in beef treated with Febantel are not absorbed and are therefore not likely to present a toxicological risk

  16. Effects of IGF-I bioavailability on bovine preantral follicular development in vitro.

    Science.gov (United States)

    Thomas, Fiona H; Campbell, Bruce K; Armstrong, David G; Telfer, Evelyn E

    2007-06-01

    The aim of this study was to determine the effect of regulation of IGF-I bioavailability on preantral follicle development in vitro. Bovine preantral follicles were cultured for 6 days in serum-free medium with increasing doses of Long R3 (LR3) IGF-I (an analog with low affinity for IGF-binding proteins (IGFBPs)), or human recombinant IGF-I (hrIGF-I). Follicle diameter and estradiol production were measured every second day. On day 6, ratios of oocyte/follicle diameter and oocyte morphology were assessed by histological examination, and IGFBP-2 and -3 were detected by immunocytochemistry and in situ hybridization respectively. Both types of IGF-I increased follicle diameter in a dose-dependent manner (P LR3 IGF-I and the highest concentration of hrIGF-I (1000 ng/ml) had smaller oocyte/follicle ratios, and increased oocyte degeneration, compared with controls or follicles treated with physiological concentrations of hrIGF-I (P < 0.05). IGFBPs were detected in cultured preantral follicles, indicating a requirement for regulation of IGF bioavailability during the early stages of follicular development. Specifically, IGFBP-3 mRNA was found to be expressed in oocytes, and IGFBP-2 immunoreactivity was detected in oocytes and granulosa cells of cultured follicles. In summary, the regulation of IGF-I bioavailability by IGFBPs is necessary for the co-ordination of oocyte and follicle development in vitro. PMID:17636166

  17. [Silica-coated ethosome as a novel oral delivery system for enhanced oral bioavailability of curcumin].

    Science.gov (United States)

    Li, Chong; Deng, Li; Zhang, Yan; Su, Ting-Ting; Jiang, Yin; Chen, Zhang-Bao

    2012-11-01

    The aim of this study is to investigate the feasibility of silica-coated ethosome as a novel oral delivery system for the poorly water-soluble curcumin (as a model drug). The silica-coated ethosomes loading curcumin (CU-SE) were prepared by alcohol injection method with homogenization, followed by the precipitation of silica by sol-gel process. The physical and chemical features of CU-SEs, and curcumin release were determined in vitro. The pharmacodynamics and bioavailability measurements were sequentially performed. The mean diameter of CU-SE was (478.5 +/- 80.3) nm and the polydispersity index was 0.285 +/- 0.042, while the mean value of apparent drug entrapment efficiency was 80.77%. In vitro assays demonstrated that CU-SEs were significantly stable with improved release properties when compared with curcumin-loaded ethosomes (CU-ETs) without silica-coatings. The bioavailability of CU-SEs and CU-ETs was 11.86- and 5.25-fold higher, respectively, than that of curcumin suspensions (CU-SUs) in in vivo assays. The silica coatings significantly promoted the stability of ethosomes and CU-SEs exhibited 2.26-fold increase in bioavailablity relative to CU-ETs, indicating that the silica-coated ethosomes might be a potential approach for oral delivery of poorly water-soluble drugs especially the active ingredients of traditional Chinese medicine with improved bioavailability. PMID:23387090

  18. Bioavailability of Silica, Titanium Dioxide, and Zinc Oxide Nanoparticles in Rats.

    Science.gov (United States)

    Kim, Mi-Kyung; Lee, Jeong-A; Jo, Mi-Rae; Choi, Soo-Jin

    2016-06-01

    Inorganic nanoparticles have been widely applied to various industrial fields and biological applications. However, the question as to whether nanoparticles are more efficiently absorbed into the systemic circulation than bulk-sized materials remains to be unclear. In the present study, the physico-chemical and dissolution properties of the most extensively developed inorganic nanoparticles, such as silica (SiO2), titanium dioxide (TiO2), and zinc oxide (ZnO), were analyzed, as compared with bulk-sized particles. Furthermore, the bioavailability of nanoparticles versus their bulk counterparts was evaluated in rats after a single oral administration and intravenous injection, respectively. The results demonstrated that all bulk materials had slightly higher crystallinity than nanoparticles, however, their dissolution properties were not affected by particle size. No significant difference in oral absorption and bioavailability of both SiO2 and TiO2 was found between nano- and bulk-sized materials, while bulk ZnO particles were more bioavailable in the body than ZnO nanoparticles. These finding will provide critical information to apply nanoparticles with high efficiency as well as to predict their toxicity potential. PMID:27427756

  19. Abiotic and biotic factors that influence the bioavailability of gold nanoparticles to aquatic macrophytes.

    Science.gov (United States)

    Glenn, J Brad; Klaine, Stephen J

    2013-09-17

    This research identified and characterized factors that influenced nanomaterial bioavailability to three aquatic plants: Azolla caroliniana Willd, Egeria densa Planch., and Myriophyllum simulans Orch. Plants were exposed to 4-, 18-, and 30-nm gold nanoparticles. Uptake was influenced by nanoparticle size, the presence of roots on the plant, and dissolved organic carbon in the media. Statistical analysis of the data also revealed that particle uptake was influenced by a 4-way (plant species, plant roots, particle size, and dissolved organic carbon) interaction suggesting nanoparticle bioavailability was a complex result of multiple parameters. Size and species dependent absorption was observed that was dependent on the presence of roots and nanoparticle size. The presence of dissolved organic carbon was found to associate with 4- and 18-nm gold nanoparticles in suspension and form a nanoparticle/organic matter complex that resulted in (1) minimized particle aggregation and (2) a decrease of nanoparticle absorption by the aquatic plants. The same effect was not observed with the 30-nm nanoparticle treatment. These results indicate that multiple factors, both biotic and abiotic, must be taken into account when predicting bioavailability of nanomaterials to aquatic plants. PMID:23947987

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

    International Nuclear Information System (INIS)

    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.

  1. Radiocesium bioavailability: Transfer of Chernobyl and tracer radiocesium to goat milk

    International Nuclear Information System (INIS)

    The bioavailability of Chernobyl-derived radiocesium in hay, fungal fruit bodies, willow bark, and soil was compared to tracer radiocesium (134CsCl) by measuring transfer coefficients (Fm) to goat milk. The average Fm value from 134CsCl of 11.9 x 10-2 d L-1 was taken to represent the maximal transfer to milk on the provided diet. In 1986, the Fm value from hay was 35% of that from 134CsCl, thus demonstrating the low bioavailability of recently deposited radiocesium. Values in 1987 were also lower, with a mean of 76% of that from tracer Cs. During 1988 and 1989, maximal Fm values were observed, suggesting increased bioavailability from the year of fallout to the following years. Transfer of radiocesium from two fungal species harvested in 1988 and 1989 were 78% and 87%, respectively, of that from tracer Cs, while bark was lower (62%). Transfer from organic soil was only 7% of tracer radiocesium, and therefore contribution from soil ingestion could only have a small impact on the content of radiocesium in animals. Live monitoring measurements and the excretion of 134Cs in milk, urine, and feces during a 50-d period was adequately described by a two-exponential equation

  2. Use of the true absorption coefficient as a measure of bioavailability of radiocaesium in ruminants

    International Nuclear Information System (INIS)

    Limitations of existing methods to describe the bioavailability of dietary radionuclides to ruminants (the transfer coefficient and apparent absorption coefficient) have led to the alternative suggestion of using the true absorption coefficient (At). Various approaches to estimating At for radiocaesium, involving the intravenous administration of a second isotope, are presented and discussed with reference to results from studies in which a range of radiocaesium sources were examined in sheep. Although estimates of At differed between the sources, they were reasonably consistent between measurement techniques. Those methods which involved the estimation of endogenous faecal excretion of radiocaesium could be used with previously contaminated animals and did not require continuous administrations of radiocaesium isotopes, but gave unreliable results for sources of low bioavailability. Methods based on estimating the turnover rate of dietary radiocaesium through blood plasma were sufficiently sensitive to measure At for the range of sources studied. However, they require previously uncontaminated animals and continuous administration of both isotopes for approximately 7 days. Bioavailability is more effectively measured as At than as the transfer or apparent absorption coefficients since At does not incorporate factors relating to the metabolism of radiocaesium in the tissues of the animal. The results of these studies show that differences in transfer coefficients between sheep and cattle and between sheep of differing ages are not due to variation in absorption across the gut. The potential for applying these approaches to other radioactive elements is discussed. (orig.). With 2 figs., 2 tabs

  3. Bioavailability of Zinc in Wistar Rats Fed with Rice Fortified with Zinc Oxide

    Directory of Open Access Journals (Sweden)

    Ceres Mattos Della Lucia

    2014-06-01

    Full Text Available The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice® is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3, supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca and magnesium (Mg in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p < 0.05. However, no differences were observed (p > 0.05 for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification.

  4. Increased mineral oil bioavailability in slurries by monovalent cation-induced dispersion

    International Nuclear Information System (INIS)

    Bioavailability of apolar contaminants is an important limiting factor for microbial reclamation of polluted soils. This paper describes a laboratory study of the relation between microaggregate stability and bioavailability of mineral oil in soil-water slurries. The stability of microaggregates in slurries is regulated by the valence and surface affinity of the cations in the system, and by the complexing anion P2O74- (metaphosphate). A silt loam, contaminated with a weathered gas oil, was collected from an oil refinery site. Degradation rates were monitored in small-scale incubations at solid:liquid ratios of 1:5 (w/w). The solution contained Ca, Na, or K as the dominant cation. The levels of nutrients and metaphosphate were varied. Biodegradation rates increased with the sequence Ca 2 treatment. Measurements of the particle size distribution the slurry showed that an increase in the finer fractions qualitatively correlated with enhanced biodegradation. This is a strong indication that dispersion of the microaggregates increased bioavailability of the contaminant

  5. Low Thermal Pretreatment as Method for Increasing the Bioavailability of Organic Matters in Domestic Mixed Sludge

    Directory of Open Access Journals (Sweden)

    Seswoya Roslinda

    2016-01-01

    Full Text Available In practice, primary and secondary sludge are fed into anaerobic digestion. However, the microbial cell exists in secondary sludge are an unfavorable substrate for biodegradation. Thermal pretreatment is proved to increase the bioavailability of organic and improve the biodegradation subsequently. During low thermal pretreatment, both intracellular (within the microbial cell and extracellular (within the polymeric network materials were extracted. This process increases the bioavailability meaning that organic compounds are accessible to the microorganisms for their degradation. This research aims to investigate the effect of thermal pretreatment on domestic mixed sludge disintegration. Domestic mixed sludge was thermally treated at 70°C for various holding times. The pre-thermally treated domestic mixed sludge was measured for protein and carbohydrates following the Lowry Method, and Phenol-Sulphuric Acid Method respectively. DR 6000 UV-Vis spectrophotometer, DRB200 Reactor (digester and COD vial (TNT plus 822 were used for COD determination, based on Reactor Digestion Method approved by USEPA. The results showed that the organic matter in domestic mixed sludge is efficiently solubilised during thermal treatment organic matter. The higher soluble yield for each monitored parameter determined in this study indicated that low thermal pretreatment improve bioavailability.

  6. Utilization of Microemulsions from Rhinacanthus nasutus (L.) Kurz to Improve Carotenoid Bioavailability.

    Science.gov (United States)

    Ho, Nai-Hsing; Inbaraj, Baskaran Stephen; Chen, Bing-Huei

    2016-01-01

    Carotenoids have been known to reduce the risk of several diseases including cancer and cardiovascular. However, carotenoids are unstable and susceptible to degradation. Rhinacanthus nasutus (L.) Kurz (R. nasutus), a Chinese medicinal herb rich in carotenoids, was reported to possess vital biological activities such as anti-cancer. This study intends to isolate carotenoids from R. nasutus by column chromatography, identify and quantify by HPLC-MS, and prepare carotenoid microemulsions for determination of absolute bioavailability in rats. Initially, carotenoid fraction was isolated using 250 mL ethyl acetate poured into an open-column packed with magnesium oxide-diatomaceous earth (1:3, w/w). Fourteen carotenoids including internal standard β-apo-8'-carotenal were resolved within 62 min by a YMC C30 column and gradient mobile phase of methanol-acetonitrile-water (82:14:4, v/v/v) and methylene chloride. Highly stable carotenoid microemulsions were prepared using a mixture of Capryol(TM)90, Transcutol®HP, Tween 80 and deionized water, with the mean particle being 10.4 nm for oral administration and 10.7 nm for intravenous injection. Pharmacokinetic study revealed that the absolute bioavailability of carotenoids in microemulsions and dispersion was 0.45% and 0.11%, respectively, while a much higher value of 6.25% and 1.57% were shown for lutein, demonstrating 4-fold enhancement in bioavailability upon incorporation of R. nasutus carotenoids into a microemulsion system. PMID:27150134

  7. Enhanced oral bioavailability and in vivo antioxidant activity of chlorogenic acid via liposomal formulation.

    Science.gov (United States)

    Feng, Yingshu; Sun, Congyong; Yuan, Yangyang; Zhu, Yuan; Wan, Jinyi; Firempong, Caleb Kesse; Omari-Siaw, Emmanuel; Xu, Yang; Pu, Zunqin; Yu, Jiangnan; Xu, Ximing

    2016-03-30

    In the present study, a formulation system consisting of cholesterol and phosphatidyl choline was used to prepare an effective chlorogenic acid-loaded liposome (CAL) with an improved oral bioavailability and an increased antioxidant activity. The developed liposomal formulation produced regular, spherical and multilamellar-shaped distribution nanoparticles. The pharmacokinetic analysis of CAL compared with chlorogenic acid (CA), showed a higher value of Cmax(6.42 ± 1.49 min versus 3.97 ± 0.39 min) and a delayed Tmax(15 min versus 10 min), with 1.29-fold increase in relative oral bioavailability. The tissue distribution in mice also demonstrated that CAL predominantly accumulated in the liver which indicated hepatic targeting potential of the drug. The increased activities of antioxidant enzymes (Total Superoxide Dismutase (T-SOD) and Glutathione Peroxidase (GSH-Px)) and total antioxidant capacity (T-AOC), in addition to decreased level of malondialdehyde (MDA) in CCl4-induced hepatotoxicity study further revealed that CAL exhibited significant hepatoprotective and antioxidant effects. Collectively, these findings present a liposomal formulation with significantly improved oral bioavailability and an increased in vivo antioxidant activity of CA. PMID:26861689

  8. Nanoencapsulation of psoralidin via chitosan and Eudragit S100 for enhancement of oral bioavailability.

    Science.gov (United States)

    Yin, Juntao; Xiang, Cuiyu; Song, Xiaoyong

    2016-08-20

    Psoralidin (PL) has recently been attracting more attention as a new anticancer agent candidate. Nevertheless, peroral administration of PL is largely challenged by its insoluble nature and intestinal efflux. This article aimed to develop a nanoencapsulation formulation of PL using water-soluble chitosan and Eudragit S100 and to evaluate its potential for bioavailability enhancement. PL-loaded nanocapsules (PL-NCs) were prepared by a solvent diffusion and high-pressure homogenization technique with Poloxamer 188 as a stabilizer. The resultant PL-NCs were approximately 132.5nm in particle size and possessed a high entrapment efficiency (98.1%). In vitro release showed that PL was released less from the nanocapsules due to electrostatic complexation. A lipolytic experiment demonstrated that our prepared PL-NCs were not degraded by lipase, in contrast with the most commonly used lipid nanoparticles. Furthermore, PL-NCs appeared to have less affinity for intestinal mucins. Following oral administration, the bioavailability of PL was significantly enhanced via the PL-NCs, with a value of 339.02% relative to the reference (suspensions). Excellent intestinal adhesion and transepithelial permeability accounted for the enhancement of oral bioavailability. Taken together, these results indicate that nanoencapsulation of PL with chitosan and Eudragit S100 is a promising strategy for improved PL oral delivery. PMID:27154253

  9. Bioavailability of PCDD/F from contaminated soil in young Goettingen minipigs

    Energy Technology Data Exchange (ETDEWEB)

    Wittsiepe, J.; Erlenkaemper, B.; Welge, P.; Hack, A.; Wilhelm, M. [Ruhr-Univ. Bochum, Abt. fuer Hygiene, Sozial- und Umweltmedizin, Bochum (Germany)

    2004-09-15

    Humans are exposed to polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) mainly via intake of food of animal origin. In contrast to the oral pathway inhalation or dermal uptake of PCDD/F is of minor relevance. For young children however, the oral ingestion of contaminated soil can be a major route of PCDD/F exposure. The objective of the present study was to examine the oral uptake and accumulation of PCDD/F from a naturally contaminated soil particularly with regards to absolute and relative bioavailability with the finally aim to extrapolate bioavailability data to human risk assessment. Minipigs are supposed to be an adequate animal model because of wide physiological and biochemical similarities to humans regarding the gastrointestinal tract. We used young pigs at the age of about 1-3 months to simulate childrens physiological age and body weight. The animals were orally exposed to known amounts of PCDD/F either soil-bound or as an extract of the same soil to determine the influence of the soil matrix on bioavailability.

  10. Extractive biodegradation and bioavailability assessment of phenanthrene in the cloud point system by Sphingomonas polyaromaticivorans.

    Science.gov (United States)

    Pan, Tao; Deng, Tao; Zeng, Xinying; Dong, Wei; Yu, Shuijing

    2016-01-01

    The biological treatment of polycyclic aromatic hydrocarbons is an important issue. Most microbes have limited practical applications because of the poor bioavailability of polycyclic aromatic hydrocarbons. In this study, the extractive biodegradation of phenanthrene by Sphingomonas polyaromaticivorans was conducted by introducing the cloud point system. The cloud point system is composed of a mixture of (40 g/L) Brij 30 and Tergitol TMN-3, which are nonionic surfactants, in equal proportions. After phenanthrene degradation, a higher wet cell weight and lower phenanthrene residue were obtained in the cloud point system than that in the control system. According to the results of high-performance liquid chromatography, the residual phenanthrene preferred to partition from the dilute phase into the coacervate phase. The concentration of residual phenanthrene in the dilute phase (below 0.001 mg/L) is lower than its solubility in water (1.18 mg/L) after extractive biodegradation. Therefore, dilute phase detoxification was achieved, thus indicating that the dilute phase could be discharged without causing phenanthrene pollution. Bioavailability was assessed by introducing the apparent logP in the cloud point system. Apparent logP decreased significantly, thus indicating that the bioavailability of phenanthrene increased remarkably in the system. This study provides a potential application of biological treatment in water and soil contaminated by phenanthrene. PMID:26392138

  11. Part II: bioavailability in beagle dogs of nimodipine solid dispersions prepared by hot-melt extrusion.

    Science.gov (United States)

    Zheng, Xin; Yang, Rui; Zhang, Yu; Wang, Zhijun; Tang, Xing; Zheng, Liangyuan

    2007-07-01

    The aim of the present work was to investigate the in vitro dissolution properties and oral bioavailability of three solid dispersions of nimodipine. The solid dispersions were compared with pure nimodipine, their physical mixtures, and the marketed drug product Nimotop. Nimodipine solid dispersions were prepared by a hot-melt extrusion process with hydroxypropyl methylcellulose (HPMC, Methocel E5), polyvinylpyrrolidone/vinyl acetate copolymer (PVP/VA, Plasdone S630), and ethyl acrylate, methyl methacrylate polymer (Eudragit EPO). Previous studies of XRPD and DSC data showed that the crystallinity was not observed in hot-melt extrudates, two T(g)s were observed in the 30% and 50% NMD-HPMC samples, indicating phase separation. The weakening and shift of the N-H stretching vibration of the secondary amine groups of nimodipine as determined by FT-IR proved hydrogen bonding between the drug and polymers in the solid dispersion. The dissolution profiles of the three dispersion systems showed that the release was improved compared with the unmanipulated drug. Drug plasma concentrations were determined by HPLC, and pharmacokinetic parameters were calculated after orally administering each preparation containing 60 mg of nimodipine. The mean bioavailability of nimodipine was comparable after administration of the Eudragit EPO solid dispersion and Nimotop, but the HPMC and PVP/VA dispersions exhibited much lower bioavailability. However, the AUC(0-12 hr) values of all three solid dispersions were significantly higher than physical mixtures with the same carriers and nimodipine powder. PMID:17654027

  12. 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.

  13. Sorption Effects on the Bioavailability and Transport of Naphthalene and 2-Naphthol in Porous Media

    Science.gov (United States)

    Famisan, G. B.; Brusseau, M. L.

    2001-05-01

    Bioavailability is one of the critical factors influencing the biodegradation and bioremediation potential of organic compounds. The bioavailability of many organic contaminants is controlled in part by the nature, magnitude, and rate of sorption/desorption processes. This study investigates the impact of sorption and associated retardation on the bioavailability, biodegradation, and transport of polycyclic aromatic hydrocarbons. A series of miscible-displacement experiments were conducted using naphthalene and 2-naphthol as the model sorbing compounds and salicylate, a degradation product of naphthalene, as a nonsorbing reference compound. Two porous media were used, one (Eustis soil) exhibiting significant sorption effects and one (quartz sand) with no measurable sorption of the compounds. The porous media were sterilized and inoculated with Pseudomonas putida RB1353, an organism that degrades naphthalene and its derivatives. The transport and biodegradation of all three substrates in quartz sand were influenced significantly by microbial lag. This was also true for salicylate in the Eustis soil system. Conversely, lag effects were not observed for naphthalene and naphthol in the Eustis soil system. As noted above, sorption to Eustis soil was significant for both naphthalene and naphthol. These results indicate that the increased residence time associated with retardation of naphthalene and naphthol in the Eustis system mediated the effects of lag on observed effluent concentrations.

  14. Mobility and bioavailability reduction of soil TNT via sorption enhancement using monopotassium phosphate.

    Science.gov (United States)

    Jung, Jae-Woong; Nam, Kyoungphile

    2014-06-30

    In this study, the effect of monopotassium phosphate (MKP) on the reduction in mobility and bioavailability of 2,4,6-trinitrotoluene (TNT) was tested. In the test soil, collected from an active firing range, of which cation binding sites were mostly exchanged with H(+) or Al(3+), potassium ions in MKP exchanged the existing cations and hence significantly increased TNT sorption. In addition, a competitive sorption experiment with hexafluorobenzene and 2,4-dinitrotoluene suggests that TNT was specifically sorbed through cation-polar interaction in the test soil. The unit-equivalent Freundlich sorption coefficient of TNT in MKP-amended soil (1370.96 mg-TNT/kg-soil) was about 13 times higher than that in untreated soil (106.23 mg-TNT/kg-soil). Finally, modified synthetic precipitation leaching procedure and hydroxypropyl-β-cyclodextrin extraction result revealed that MKP application could reduce both the leachability and bioavailability of soil TNT. The leachable and extractable fraction of TNT in untreated soil were 87.63% and 94.47% of the initial TNT, respectively, whereas these fractions decreased to 49.15% and 54.85% of the initial TNT in the presence of MKP, respectively. MKP application can be a benign technology which can reduce both mobility and bioavailability of TNT in soil. PMID:24835687

  15. Migration and bioavailability of 137Cs in forest soil of southern Germany

    International Nuclear Information System (INIS)

    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

  16. Migration and bioavailability of {sup 137}Cs in forest soil of southern Germany

    Energy Technology Data Exchange (ETDEWEB)

    Konopleva, I.; Klemt, E. [Hochschule Ravensburg-Weingarten, University of Applied Sciences, 88250 Weingarten (Germany); Konoplev, A. [Scientific Production Association ' TYPHOON' , Obninsk (Russian Federation); Zibold, G. [Hochschule Ravensburg-Weingarten, University of Applied Sciences, 88250 Weingarten (Germany)], E-mail: zibold@hs-weingarten.de

    2009-04-15

    To give a quantitative description of the radiocaesium soil-plant transfer for fern (Dryopteris carthusiana) and blackberry (Rubus fruticosus), physical and chemical properties of soils in spruce and mixed forest stands were investigated. Of special interest was the selective sorption of radiocaesium, which was determined by measuring the Radiocaesium Interception Potential (RIP). Forest soil and plants were taken at 10 locations of the Altdorfer Wald (5 sites in spruce forest and 5 sites in mixed forest). It was found that the bioavailability of radiocaesium in spruce forest was on average seven times higher than in mixed forest. It was shown that important factors determining the bioavailability of radiocaesium in forest soil were its exchangeability and the radiocaesium interception potential (RIP) of the soil. Low potassium concentration in soil solution of forest soils favors radiocaesium soil-plant transfer. Ammonium in forest soils plays an even more important role than potassium as a mobilizer of radiocaesium. The availability factor - a function of RIP, exchangeability and cationic composition of soil solution - characterized reliably the soil-plant transfer in both spruce and mixed forest. For highly organic soils in coniferous forest, radiocaesium sorption at regular exchange sites should be taken into account when its bioavailability is considered.

  17. Effect of biochar amendment on the bioavailability of pesticide chlorantraniliprole in soil to earthworm.

    Science.gov (United States)

    Wang, Ting-Ting; Cheng, Jie; Liu, Xian-Jin; Jiang, Wayne; Zhang, Chao-Lan; Yu, Xiang-Yang

    2012-09-01

    To evaluate the effect of biochar amendment on the bioavailability of chlorantraniliprole (CAP) in soils with different physico-chemical properties, the uptake of CAP from various soils by earthworms was studied. It was observed that the biochar amendment of the soils affected the sorption of CAP, but the magnitude of the sorption enhancement by biochar amendment among the soils was varied, presumably due to the attenuation of the sorptivity of the biochar when amended in the soil. The amendment with biochars leads to a decrease in the bioavailability of CAP in the soils to earthworms, and more prominent for biochar BC850 amendment. In the soil with a CAP concentration of 10 mg kg(-1), the residue of CAP in the earthworm tissues was found to be 9.65 mg kg(-1), in comparison with that the CAP residue was 4.05 mg kg(-1) in BC450 amended soil and 0.59 mg kg(-1) in BC850, respectively. The degree of bioavailability reduction by same level of biochar amendment was different among soils with different properties. The results demonstrate that the properties of soils are important to performance of biochar in soil. PMID:22776710

  18. Montmorillonite intercalated with glutathione for antioxidant delivery: synthesis, characterization, and bioavailability evaluation.

    Science.gov (United States)

    Baek, Miri; Choy, Jin-Ho; Choi, Soo-Jin

    2012-04-01

    A most powerful antioxidant, glutathione (GSH), plays an important role in detoxification, immune response, and protection against reactive oxygen species. However, orally ingested GSH can be easily degradable to free amino acids by chemical and enzymatic hydrolysis, resulting in low bioavailability. The aim of this study was, therefore, to enhance GSH bioavailability by developing GSH-montmorillonite (MMT) hybrid system. It was also coated with polyvinylacetal diethylaminoacetate (AEA) for better stability. Both GSH-MMT and AEA-GSH-MMT hybrids were characterized by powder X-ray diffraction (PXRD), Fourier transformed infrared (FT-IR), and thermogravimetric analysis (TGA), indicating that GSH was successfully intercalated into the interlayer spaces of MMT. In vivo antioxidant activity assay revealed that AEA-GSH-MMT hybrid significantly increased antioxidant activity in the plasma after oral administration in mice. Pharmacokinetic study also indicated that AEA-GSH-MMT hybrid considerably increased the plasma concentration of GSH at 1h post-oral administration. Moreover, both the hybrid systems remarkably enhanced GSH delivery to the main target tissue, liver. All the results suggest that GSH-MMT hybrid systems have great potential to enhance bioavailability of oral GSH, providing new insight into their pharmaceutical application. PMID:22266539

  19. Bioavailability of Heme Iron in Biscuit Filling Using Piglets as an Animal Model for Humans

    Directory of Open Access Journals (Sweden)

    Adrián Guillermo Quintero-Gutiérrez, Guillermina González-Rosendo, Jonathan Sánchez-Muñoz, Javier Polo-Pozo, José Juan Rodríguez-Jerez

    2008-01-01

    Full Text Available The objective of this work was to evaluate the bioavailability of heme iron added to biscuit filling. It comprised two stages: first, the development of the heme iron enriched biscuit filling; second, the evaluation of the bioavailability of the mineral in fattening piglets. Two groups were selected randomly and fed: a Low iron feed and biscuits with heme iron supplemented filling; b Normal feed (with ferrous sulphate. Weight and blood parameters were measured every fifteen days. Averages were compared after duplicate analyses. The filling had a creamy appearance, chocolate taste and smell, appropriate spreadability, heme iron content of 2.6 mg per gram and a shelf-life of a month. The heme iron supplemented pigs registered a greater (P<0.05 weight gain (27.8% more than the control group. Mortality in the heme iron group was 10%, compared to 50% in the control group. The amount of iron measured in the different compartment was greater in the heme group (3315 mg than in the control group (2792 mg. However, the amount of iron consumed in the latter was greater. We show that an acceptable product with high heme iron content can be formulated, suitable for use as biscuit filling. The heme iron supplement produced better weight increase and lesser mortality in fattening pigs. The bioavailability of heme iron was 23% greater (P<0.05 compared to ferrous sulphate.

  20. Development and characterization of nanosuspensions of olmesartan medoxomil for bioavailability enhancement

    Directory of Open Access Journals (Sweden)

    Hetal Paresh Thakkar

    2011-01-01

    Full Text Available Background : Olmesartan medoxomil (OLM, an anti-hypertensive agent administered orally has absolute bioavailability of only 26% due to the poor aqueous solubility (<7.75 μg/ml. The present investigation aimed at enhancing the oral bioavailability of OLM by improving its solubility and dissolution rate by preparing nanosuspensions. Materials and methods : The nanosuspensions of OLM were prepared using media milling technique followed by its lyophilization using mannitol as a cryoprotectant. Various formulation as well as process parameters were optimized in order to achieve desirable size and saturation solubility. Characterization of the prepared nanosuspension was done with respect to particle size, zeta potential, saturation solubility, dissolution rate, morphology study (TEM, in-vitro and exvivo drug diffusion study. Evaluation of the crystalline state before and after particle size reduction was done by differential scanning calorimetry (DSC and powder X-ray diffraction (PXRD. Results : The results indicated that the initial crystalline state is preserved following particle size reduction and that the saturation solubility, dissolution velocity and diffusion rate of the drug from the nanosuspension is significantly higher than that of the plain drug suspension as well as from the marketed tablet formulation. Conclusion : Nanosuspension seems to be a promising approach for bioavailability enhancement because of the simple method of its preparation and its universal applicability.

  1. Variations in the bioavailability of polycyclic aromatic hydrocarbons in industrial and agricultural soils after bioremediation.

    Science.gov (United States)

    Guo, Meixia; Gong, Zongqiang; Allinson, Graeme; Tai, Peidong; Miao, Renhui; Li, Xiaojun; Jia, Chunyun; Zhuang, Jie

    2016-02-01

    The aim of this study was to demonstrate the variations in bioavailability remaining in industrial and agricultural soils contaminated by polycyclic aromatic hydrocarbons (PAHs) after bioremediation. After inoculation of Mycobacterium sp. and Mucor sp., PAH biodegradation was tested on a manufactured gas plant (MGP) soil and an agricultural soil. PAH bioavailability was assessed before and after biodegradation using solid-phase extraction (Tenax-TA extraction) and solid-phase micro-extraction (SPME) to represent bioaccessibility and chemical activity of PAHs, respectively. Only 3- and 4-ring PAHs were noticeably biodegradable in the MGP soil. PAH biodegradation in the agricultural soil was different from that in the MGP soil. The rapidly desorbing fractions (F(rap)) extracted by Tenax-TA and the freely dissolved concentrations of 3- and 4-ring PAHs determined by SPME from the MGP soil decreased after 30 days biodegradation; those values of the 5- and 6-ring PAHs changed to a lesser degree. For the agricultural soil, the F(rap) values of the 3- and 4-ring PAHs also decreased after the biodegradation experiment. The Tenax-TA extraction and the SPME have the potential to assess variations in the bioavailability of PAHs and the degree of biodegradation in contaminated MGP soils. In addition, Tenax-TA extraction is more sensitive than SPME when used in the agricultural soil. PMID:26498099

  2. Development and Evaluation of Solid Lipid Nanoparticles of Raloxifene Hydrochloride for Enhanced Bioavailability

    Directory of Open Access Journals (Sweden)

    Anand Kumar Kushwaha

    2013-01-01

    Full Text Available Raloxifene hydrochloride (RL-HCL is an orally selective estrogen receptor modulator (SERM with poor bioavailability of nearly 2% due to its poor aqueous solubility and extensive first pass metabolism. In order to improve the oral bioavailability of raloxifene, raloxifene loaded solid lipid nanoparticles (SLN have been developed using Compritol 888 ATO as lipid carrier and Pluronic F68 as surfactant. Raloxifene loaded SLN were prepared by solvent emulsification/evaporation method, and different concentrations of surfactant, and homogenization speed were taken as process variables for optimization. SLN were characterized for particle size, zeta potential, entrapment efficiency, surface morphology, and crystallinity of lipid and drug. In vitro drug release studies were performed in phosphate buffer of pH 6.8 using dialysis bag diffusion technique. Particle sizes of all the formulations were in the range of 250 to 1406 nm, and the entrapment efficiency ranges from 55 to 66%. FTIR and DSC studies indicated no interaction between drug and lipid, and the XRD spectrum showed that RL-HCL is in amorphous form in the formulation. In vitro release profiles were biphasic in nature and followed Higuchi model of release kinetics. Pharmacokinetics of raloxifene loaded solid lipid nanoparticles after oral administration to Wistar rats was studied. Bioavailability of RL-HCL loaded SLN was nearly five times than that of pure RL-HCL.

  3. Bioavailability of soy isoflavones through placental/lactational transfer and soy food

    International Nuclear Information System (INIS)

    Isoflavones are non-nutritive components of soy responsible for estrogenic responses observed in vitro and in experimental animals. Possible beneficial effects (e.g., reduction of serum lipids, increased bone mineral density, relief of hot flashes and other menopausal symptoms, mammary and prostate cancer chemoprevention) in humans have been attributed to consumption of isoflavones but evidence for potential adverse effects (e.g., stimulation of estrogen-dependent mammary tumors and aberrant perinatal development) has also been reported in experimental animal models. Bioavailability from appropriate food matrices and exposure during different life stages are both critical determinants of isoflavone effects. For these reasons, it is important to compare isoflavone bioavailability in adults to that in fetal and neonatal animals for a more complete understanding of potential susceptibility issues. Studies of the major soy isoflavone genistein were conducted in pregnant and lactating Sprague-Dawley rats to quantify placental and lactational transfer to plasma and brain to understand better biological effects observed in multigenerational studies. In addition, studies were conducted with genistein in adult Balb/c mice to define absolute bioavailability from both gavage and soy protein isolate (SPI)-containing food. The information derived from these studies makes it possible to predict internal exposures of children to genistein from soy infant formula, which is manufactured using SPI.

  4. Bioavailability as an issue in risk assessment and management of food cadmium: A review

    International Nuclear Information System (INIS)

    The bioavailability of cadmium (Cd) from food is an important determinant of the potential risk of this toxic element. This review summarizes the effects of marginal deficiencies of the essential nutrients zinc (Zn), iron (Fe), and calcium (Ca) on the enhancement of absorption and organ accumulation and retention of dietary Cd in laboratory animals. These marginal deficiencies enhanced Cd absorption as much as ten-fold from diets containing low Cd concentrations similar to that consumed by some human populations, indicating that people who are nutritionally marginal with respect to Zn, Fe, and Ca are at higher risk of Cd disease than those who are nutritionally adequate. Results from these studies also suggest that the bioavailability of Cd is different for different food sources. This has implications for the design of food safety rules for Cd in that if the dietary source plays such a significant role in the risk of Cd, then different foods would require different Cd limits. Lastly, the importance of food-level exposures of Cd and other potentially toxic elements in the study of risk assessment are emphasized. Most foods contain low concentrations of Cd that are poorly absorbed, and it is neither relevant nor practical to use toxic doses of Cd in experimental diets to study food Cd risks. A more comprehensive understanding of the biochemistry involved in the bioavailability of Cd from foods would help resolve food safety questions and provide the support for a badly needed advance in international policies regarding Cd in crops and foods

  5. Enhancement of bioavailability and anthelmintic efficacy of albendazole by solid dispersion and cyclodextrin complexation techniques.

    Science.gov (United States)

    Kalaiselvan, R; Mohanta, G P; Madhusudan, S; Manna, P K; Manavalan, R

    2007-08-01

    The objective of this study was to improve the oral bioavailability and therapeutic efficacy of albendazole (ABZ) employing solid dispersion and cyclodextrin complexation techniques. Solid dispersion (dispersion) was prepared using ABZ and polyvinylpyrrolidone (PVP) polymer (1:1 weight ratio). Ternary inclusion complex (ternary complex) was prepared using ABZ, hydroxypropyl beta-cyclodextrin (HPbetaCD) and L-tartaric acid (1:1:1 molar ratio). In rabbits with high gastric acidity (gastric pH approximately 1), ternary complex and solid dispersion showed a bioavailability enhancement of 3.2 and 2.4 fold respectively, compared to a commercial suspension (p 5) caused a 62% reduction in AUC (area under the plasma level curve) for the commercial suspension, whereas the reduction in case of PVP dispersion and ternary complex was only 43% and 37% respectively. The rapid absorption of the drug from solid dispersion and ternary complex was reflected in improved anthelmintic efficacy against the systemic phases of Trichinella spiralis. The ternary complex was significantly more efficient than solid dispersion and exhibited the highest larvicidal activity (90%) at a dose of 50 mg x kg(-1) (p < 0.05). These results suggest that the bioavailability and therapeutic efficacy of the ternary complex might be high even if there is a great variation in the gastric pH. PMID:17867556

  6. Bioavailability of residual polycyclic aromatic hydrocarbons following enhanced natural attenuation of creosote-contaminated soil

    International Nuclear Information System (INIS)

    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. MicrotoxTM results for aqueous soil extracts indicated that there was no significant difference in EC50 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.

  7. Iron deficiency and bioavailability in anaerobic batch and submerged membrane bioreactors (SAMBR) during organic shock loads.

    Science.gov (United States)

    Ketheesan, Balachandran; Thanh, Pham Minh; Stuckey, David C

    2016-07-01

    This study examined the effects of Fe(2+) and its bioavailability for controlling VFAs during organic shock loads in batch reactors and a submerged anaerobic membrane bioreactor (SAMBR). When seed grown under Fe-sufficient conditions (7.95±0.05mgFe/g-TSS), an organic shock resulted in leaching of Fe from the residual to organically bound and soluble forms. Under Fe-deficient seed conditions (0.1±0.002mgFe/gTSS), Fe(2+) supplementation (3.34mgFe(2+)/g-TSS) with acetate resulted in a 2.1-3.9 fold increase in the rate of methane production, while with propionate it increased by 1.2-1.5 fold compared to non-Fe(2+) supplemented reactors. Precipitation of Fe(2+) as sulphides and organically bound Fe were bioavailable to methanogens for acetate assimilation. The results confirmed that the transitory/long term limitations of Fe play a significant role in controlling the degradation of VFAs during organic shock loads due to their varying physical/chemical states, and bioavailability. PMID:27015020

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

    Science.gov (United States)

    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.

  9. Bioavailability of the Nano-Unit 14C-Agrochemicals Under Various Water Potential.

    Science.gov (United States)

    Jung, S C; Kim, H G; Kuk, Y I; Ahn, H G; Senseman, S A; Lee, D J

    2015-08-01

    The study was conducted to investigate the effects of water potential on bioavailability of the nano-unit 14C-cafenstrole, 14C-pretilachlor, 14C-benfuresate, 14C-simetryn and 14C-oxyfluorfen applied with or without dimepiperate or daimuron under various water potential conditions. The highest bioavailable concentration in soil solution (BCSS) was found at 60% soil moisture, while the lowest occurred at 50% soil moisture for soil-applied alone or in combination. All water potential conditions differed significantly from each other with variations in total bioavailable amount in soil solution (TBSS) when either dimepiperate or daimuron were added to the soil, and changes were directly proportional to variations in water potential. Across all treatments, TBSS at 80% soil moisture was three to four times greater than that at 50% soil moisture when applied alone or in combination with dimepiperate or daimuron. Cafenstrole and simetryn had distribution coefficient (Kd) values <64 ml g-1 and a TBSS ranging from 10 to 44 ng g-1 soil, regardless of water potential conditions applied alone or in combination. Pretilachlor and benfuresate had Kd values <15 ml g-1 and a TBSS range of 38 to 255 ng g-1 soil when applied with or without dimepiperate or daimuron. PMID:26369226

  10. Speciation and bioavailability of soil nutrients: effect on crop production and environment

    Directory of Open Access Journals (Sweden)

    Elisabetta Barberis

    Full Text Available The agricultural production, determining the quality of the foodstuffs, depends on the biological characteristics of the crops and on the environmental properties, where soil environment plays a central role. Crops absorb water and nutritive elements from soil, but they can intake toxic elements as well. The potential benefits, or dangers, due to the presence of a certain element in soil, depend on its chemical speciation regulating its bioavailability, toxicity, environmental mobility, and biogeochemistry. Elements may exist in soil in different redox species and organic or inorganic forms. They may thus undergo different chemical processes occurring in solution, in the solid phase, or at the solid-water interface. The chemical speciation and bioavailability of the elements are affected by soil and environmental properties, which may undergo natural or anthropogenic modifications. As an example, we reported here some aspects linked to the chemical speciation, bioavailability and environmental fate of two chemically similar elements. The former, phosphorus, is a macronutrient element, essential for plant growth, while the latter, arsenic, is strongly toxic for most living organisms.

  11. Factors limiting the extent of absolute bioavailability of pradefovir in rat.

    Science.gov (United States)

    Xiao, Qingqing; Yang, Wanqiu; Wang, Dan; Chen, Lin; Yuan, Linwen; Ding, Yitao; Yang, Jin

    2016-10-01

    1. Pradefovir was designed as an oral liver target prodrug of 9-(2-phosphonylmethoxyethyl) adenine (PMEA). Liver targeting arises through first pass hepatic metabolism by cytochrome P-450 3A4 (CYP3A4). For CYP3A4 primarily exists in intestines and liver, intestinal metabolism may impair its liver selectivity and oral bioavailability, and then impair its efficacy and safety. It was important to reveal details of the disposition of pradefovir in intestines and liver in a preclinical study. 2. The absolute bioavailability of pradefovir was 4.75% based on the intravenous and oral AUC0-24 h in rats. Pradefovir was stable in intestinal segments and microsomes. The fractions of the dose absorbed from the GI tract were 20.3% and 15.3% from intravenous and oral administration of pradefovir in rats and portal vein-cannulated rat models, respectively. The liver extraction ratio was predicted to be 49.2% from liver microsomes system, based on the monitoring substrate loss rate. Rat intestines' Ussing chamber experiment indicated that P-glycoprotein (P-gp) transporter and paracellular pathway may involve in intestinal transportation. 3. Activation of pradefovir mainly occurs in the liver. Low intestinal absorption was the main reason of low bioavailability of pradefovir in rats. The result was suggestive for the disposition of pradefovir in human intestine and liver. PMID:26846680

  12. Enhanced bioavailability of apigenin via preparation of a carbon nanopowder solid dispersion.

    Science.gov (United States)

    Ding, Shu-min; Zhang, Zhen-hai; Song, Jie; Cheng, Xu-dong; Jiang, Jun; Jia, Xiao-bin

    2014-01-01

    In this study, a novel carbon nanopowder (CNP) drug carrier was developed to improve the oral bioavailability of apigenin (AP). Solid dispersions (SDs) of AP with CNP were prepared, and their in vitro drug release and in vivo performance were evaluated. The physicochemical properties of the formulations were examined by differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy. Drug release profiles showed that AP dissolution from the CNP-AP system (weight ratio, 6:1) after 60 minutes improved by 275% compared with that of pure AP. Moreover, the pharmacokinetic analysis of SD formulations in rats showed that the AP area under the curve0-t value was 1.83 times higher for the CNP-AP system than for pure AP, indicating that its bioavailability was significantly improved. In addition, compared with pure AP, SDs had a significantly higher peak and shorter time to peak. Preliminary intestinal toxicity tests indicated that there was no significant difference in the tissues of the rats treated with the CNP-AP system, rats treated with the CNP alone, and controls. In conclusion, CNP-based SDs could be used for enhancing the bioavailability of poorly water-soluble drugs while also improving drug safety. PMID:24872695

  13. Bioavailability of anthocyanins and colonic polyphenol metabolites following consumption of aronia berry extract.

    Science.gov (United States)

    Xie, Liyang; Lee, Sang Gil; Vance, Terrence M; Wang, Ying; Kim, Bohkyung; Lee, Ji-Young; Chun, Ock K; Bolling, Bradley W

    2016-11-15

    A single-dose pharmacokinetic trial was conducted in 6 adults to evaluate the bioavailability of anthocyanins and colonic polyphenol metabolites after consumption of 500mg aronia berry extract. UHPLC-MS methods were developed to quantitate aronia berry polyphenols and their metabolites in plasma and urine. While anthocyanins were bioavailable, microbial phenolic catabolites increased ∼10-fold more than anthocyanins in plasma and urine. Among the anthocyanins, cyanidin-3-O-galactoside was rapidly metabolized to peonidin-3-O-galactoside. Aronia polyphenols were absorbed and extensively metabolized with tmax of anthocyanins and other polyphenol catabolites from 1.0h to 6.33h in plasma and urine. Despite significant inter-individual variation in pharmacokinetic parameters, concentrations of polyphenol metabolites in plasma and urine at 24h were positively correlated with total AUC in plasma and urine (r=0.93, and r=0.98, respectively). This suggests that fasting blood and urine collections could be used to estimate polyphenol bioavailability and metabolism after aronia polyphenol consumption. PMID:27283706

  14. Quantum Chemical and Docking Insights into Bioavailability Enhancement of Curcumin by Piperine in Pepper.

    Science.gov (United States)

    Patil, Vaishali M; Das, Sukanya; Balasubramanian, Krishnan

    2016-05-26

    We combine quantum chemical and molecular docking techniques to provide new insights into how piperine molecule in various forms of pepper enhances bioavailability of a number of drugs including curcumin in turmeric for which it increases its bioavailability by a 20-fold. We have carried out docking studies of quantum chemically optimized piperine structure binding to curcumin, CYP3A4 in cytochrome P450, p-Glycoprotein and UDP-glucuronosyltransferase (UGT), the enzyme responsible for glucuronosylation, which increases the solubility of curcumin. All of these studies establish that piperine binds to multiple sites on the enzymes and also intercalates with curcumin forming a hydrogen bonded complex with curcumin. The conjugated network of double bonds and the presence of multiple charge centers of piperine offer optimal binding sites for piperine to bind to enzymes such as UDP-GDH, UGT, and CYP3A4. Piperine competes for curcumin's intermolecular hydrogen bonding and its stacking propensity by hydrogen bonding with enolic proton of curcumin. This facilitates its metabolic transport, thereby increasing its bioavailability both through intercalation into curcumin layers through intermolecular hydrogen bonding, and by inhibiting enzymes that cause glucuronosylation of curcumin. PMID:27111639

  15. Lac Dufault sediment core trace metal distribution, bioavailability and toxicity to Hyalella azteca

    International Nuclear Information System (INIS)

    To determine changes in metal distribution, bioavailability and toxicity with sediment depth, two 20-cm-long replicate cores were collected from a lake historically subjected to the influence of metal mining and smelting activity. The vertical distribution of Pb, Cd and Cu in sediment was similar for all three metals, with the surface layers showing enrichment and the deeper (pre-industrial) layers showing lower concentrations. Toxicity of each sediment core section was determined in laboratory tests with the freshwater amphipod Hyalella azteca. Bioavailable metal in each sediment slice was estimated from metal concentrations in overlying water in these toxicity tests and, for Cd, also from metal bioaccumulation. The profile for Cd in tissue was comparable to Cd in sediment and overlying water, but relative Cd bioavailability from sediment increased with sediment depth. Survival increased with increasing sediment depth, suggesting that surface sediments were probably less or non-toxic before industrialization. - Toxicity and bioaccumulation tests with sediment cores provide more information on biological effects of metals than surface sediment tests

  16. Measures of bioavailable serum sex hormone levels in aging Chinese by protein chip

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yong; DU Guanhua; CHANG Shuying; MENG Xiaoluo; YU Huafeng; WANG Luning; HE Jinggui; ZHANG Baohe; ZHANG Juntian; GENG Meiyu

    2006-01-01

    The purpose of this study was to develop a protein chip technique based on receptor binding assays to measure bioavailable serum sex hormone levels (BSSHL). 224 aging healthy Chinese were investigated to get the referenced values of BSSHL for the first time. In the assays recombined sex hormone receptor proteins were jointed to polysaccharide coated slides to make protein chip, and the dose-dependence curves of sex hormone on chip were prepared. The data showed that this method had good precision (CV<16%) and accuracy (Bias<10%), and the sensitivity could reach 1 pmol/L. From the results, BSSHL of men and women declined with aging, but no significant differences were observed. The BSSHL of aging men were higher than those of women. The bioavailable serum androgen level of men was 52―112 pmol/L, women's was 3―70 pmol/L and the whole group was 41.9―81.4 pmol/L. The bioavailable serum estrogen level of men was 0.8―3.0 pmol/L, women's was 1.2―2.5 pmol/L and the whole group was 0.6―2.64 pmol/L. Based on the assays, BSSHL measurement by protein chip can meet the needs of epidemiological studies in terms of speed, accuracy and sample volume required, and was helpful in quantitative assessment of aging people's health.

  17. Online detection of waterborne bioavailable copper by valve daily rhythms in freshwater clam Corbicula fluminea.

    Science.gov (United States)

    Jou, L J; Chen, W Y; Liao, C M

    2009-08-01

    Freshwater clam Corbicula fluminea, a surrogate species in metal toxicity testing, is a promising bioindicator of impairment in aquatic ecosystems. Little is known, however, about the relationship between clam valve daily rhythmic response and metal bioavailability related to a metal biological early warning system (BEWS) design. The purpose of this study was to link biotic ligand model (BLM)-based bioavailability and valve daily rhythm in C. fluminea to design a biomonitoring system for online in situ detection of waterborne copper (Cu). We integrated the Hill-based dose-time-response function and the fitted daily rhythm function of valve closure into a constructed programmatic mechanism. The functional presentation of the present dynamic system was completely demonstrated by employing a LabVIEW graphic control program in a personal computer. We used site-specific effect concentration causing 10% of total valve closure response (EC10) as the detection threshold to implement the proposed C. fluminea-based Cu BEWS. Here our results show that the proposed C. fluminea-based BEWS could be deliberately synthesized to online in situ transmit rapidly the information on waterborne bioavailable Cu levels under various aquatic environmental conditions through monitoring the valve daily rhythmic changes. We suggested that the developed C. fluminea-based dynamic biomonitoring system could assist in developing technically defensible site-specific water quality criteria to promote more efficient uses in water resources for protection of species health in aquatic environments. PMID:18607762

  18. Improving dissolution and oral bioavailability of pranlukast hemihydrate by particle surface modification with surfactants and homogenization

    Directory of Open Access Journals (Sweden)

    Ha ES

    2015-06-01

    Full Text Available Eun-Sol Ha,1 In-hwan Baek,2 Jin-Wook Yoo,1 Yunjin Jung,1 Min-Soo Kim1 1College of Pharmacy, Pusan National University, 2College of Pharmacy, Kyungsung University, Busan, Republic of Korea Abstract: The present study was carried out to develop an oral formulation of pranlukast hemihydrate with improved dissolution and oral bioavailability using a surface-modified microparticle. Based on solubility measurements, surface-modified pranlukast hemihydrate microparticles were manufactured using the spray-drying method with hydroxypropylmethyl cellulose, sucrose laurate, and water and without the use of an organic solvent. The hydrophilicity of the surface-modified pranlukast hemihydrate microparticle increased, leading to enhanced dissolution and oral bioavailability of pranlukast hemihydrate without a change in crystallinity. The surface-modified microparticles with an hydroxypropylmethyl cellulose/sucrose laurate ratio of 1:2 showed rapid dissolution of up to 85% within 30 minutes in dissolution medium (pH 6.8 and oral bioavailability higher than that of the commercial product, with approximately 2.5-fold and 3.9-fold increases in area under the curve (AUC0→12 h and peak plasma concentration, respectively. Therefore, the surface-modified microparticle is an effective oral drug delivery system for the poorly water-soluble therapeutic pranlukast hemihydrate. Keywords: solubility, wettability, sucrose laurate, cellulose

  19. Lac Dufault sediment core trace metal distribution, bioavailability and toxicity to Hyalella azteca

    Energy Technology Data Exchange (ETDEWEB)

    Nowierski, Monica [Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Dixon, D. George [Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Borgmann, Uwe [National Water Research Institute, Canada Centre for Inland Waters, 867 Lakeshore Road, PO Box 5050, Burlington, Ontario L7R 4A6 (Canada)]. E-mail: uwe.borgmann@ec.gc.ca

    2006-02-15

    To determine changes in metal distribution, bioavailability and toxicity with sediment depth, two 20-cm-long replicate cores were collected from a lake historically subjected to the influence of metal mining and smelting activity. The vertical distribution of Pb, Cd and Cu in sediment was similar for all three metals, with the surface layers showing enrichment and the deeper (pre-industrial) layers showing lower concentrations. Toxicity of each sediment core section was determined in laboratory tests with the freshwater amphipod Hyalella azteca. Bioavailable metal in each sediment slice was estimated from metal concentrations in overlying water in these toxicity tests and, for Cd, also from metal bioaccumulation. The profile for Cd in tissue was comparable to Cd in sediment and overlying water, but relative Cd bioavailability from sediment increased with sediment depth. Survival increased with increasing sediment depth, suggesting that surface sediments were probably less or non-toxic before industrialization. - Toxicity and bioaccumulation tests with sediment cores provide more information on biological effects of metals than surface sediment tests.

  20. Gastrointestinal modifications and bioavailability of brown seaweed phlorotannins and effects on inflammatory markers.

    Science.gov (United States)

    Corona, Giulia; Ji, Yang; Anegboonlap, Prapaporn; Hotchkiss, Sarah; Gill, Chris; Yaqoob, Parveen; Spencer, Jeremy P E; Rowland, Ian

    2016-04-01

    Brown seaweeds such as Ascophyllum nodosum are a rich source of phlorotannins (oligomers and polymers of phloroglucinol units), a class of polyphenols that are unique to Phaeophyceae. At present, there is no information on the bioavailability of seaweed polyphenols and limited evidence on their bioactivity in vivo. Consequently, we investigated the gastrointestinal modifications in vitro of seaweed phlorotannins from A. nodosum and their bioavailability and effect on inflammatory markers in healthy participants. In vitro, some phlorotannin oligomers were identified after digestion and colonic fermentation. In addition, seven metabolites corresponding to in vitro-absorbed metabolites were identified. Urine and plasma samples contained a variety of metabolites attributed to both unconjugated and conjugated metabolites (glucuronides and/or sulphates). In both urine and plasma, the majority of the metabolites were found in samples collected at late time points (6-24 h), suggesting colonic metabolism of high-molecular-weight phlorotannins, with three phlorotannin oligomers (hydroxytrifuhalol A, 7-hydroxyeckol, C-O-C dimer of phloroglucinol) identified in urine samples. A significant increase of the cytokine IL-8 was also observed. Our study shows for the first time that seaweed phlorotannins are metabolised and absorbed, predominantly in the large intestine, and there is a large inter-individual variation in their metabolic profile. Three phlorotannin oligomers present in the capsule are excreted in urine. Our study is the first investigation of the metabolism and bioavailability of seaweed phlorotannins and the role of colonic biotransformation. In addition, IL-8 is a possible target for phlorotannin bioactivity. PMID:26879487