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

Science.gov (United States)

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

Bioavailability and biodistribution of nanodelivered lutein

Science.gov (United States)

The aim of the study was to evaluate the ability of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NP) to enhance lutein bioavailability. The bioavailability of free lutein and PLGA-NP lutein in rats was assessed by determining plasma pharmacokinetics and deposition in selected tissues. Lutein ...

Pharmaceutical and pharmacological approaches for bioavailability

Indian Academy of Sciences (India)

Much research has been done to determine drug–drug and herb–drug interactions for improving the bioavailability of etoposide. The present article gives insight on pharmaceutical and pharmacological attempts made from time to time to overcome the erratic inter- and intra-patient variability for improving the bioavailability ...

Aluminum bioavailability from tea infusion.

Science.gov (United States)

Yokel, Robert A; Florence, Rebecca L

2008-12-01

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

Methotrexate bioavailability

NARCIS (Netherlands)

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

2010-01-01

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

Assessing arsenic bioavailability through the use of bioassays

Science.gov (United States)

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

2009-12-01

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

Bioavailability of zinc, copper, and manganese from infant diets

International Nuclear Information System (INIS)

Bell, J.G.

1987-01-01

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

Bioavailability as a tool in site management

NARCIS (Netherlands)

Harmsen, J.; Naidu, R.

2013-01-01

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

Bioavailability enhancers of herbal origin: An overview

Science.gov (United States)

Kesarwani, Kritika; Gupta, Rajiv

2013-01-01

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

Phosphorous bioavailability along a soil chronosequence

Science.gov (United States)

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

2011-12-01

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

Bioavailability of curcumin: problems and promises.

Science.gov (United States)

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

2007-01-01

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

Speciation and bioavailability of lead in complementary medicines

International Nuclear Information System (INIS)

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

2016-01-01

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

Factors influencing zinc bioavailability in rats

International Nuclear Information System (INIS)

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

1986-01-01

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

Bioavailability of bioactive food compounds: a challenging journey to bioefficacy

Science.gov (United States)

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

2013-01-01

Bioavailability is a key step in ensuring bioefficacy of bioactive food compounds or oral drugs. Bioavailability is a complex process involving several different stages: liberation, absorption, distribution, metabolism and elimination phases (LADME). Bioactive food compounds, whether derived from various plant or animal sources, need to be bioavailable in order to exert any beneficial effects. Through a better understanding of the digestive fate of bioactive food compounds we can impact the promotion of health and improvement of performance. Many varying factors affect bioavailability, such as bioaccessibility, food matrix effect, transporters, molecular structures and metabolizing enzymes. Bioefficacy may be improved through enhanced bioavailability. Therefore, several technologies have been developed to improve the bioavailability of xenobiotics, including structural modifications, nanotechnology and colloidal systems. Due to the complex nature of food bioactive compounds and also to the different mechanisms of absorption of hydrophilic and lipophilic bioactive compounds, unravelling the bioavailability of food constituents is challenging. Among the food sources discussed during this review, coffee, tea, citrus fruit and fish oil were included as sources of food bioactive compounds (e.g. (poly)phenols and polyunsaturated fatty acids (PUFAs)) since they are examples of important ingredients for the food industry. Although there are many studies reporting on bioavailability and bioefficacy of these bioactive food components, understanding their interactions, metabolism and mechanism of action still requires extensive work. This review focuses on some of the major factors affecting the bioavailability of the aforementioned bioactive food compounds. PMID:22897361

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

Science.gov (United States)

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

2018-06-01

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

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.

The influence of dissolved phosphorus molecular form on recalcitrance and bioavailability

International Nuclear Information System (INIS)

Li, Bo; Brett, Michael T.

2013-01-01

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

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

Science.gov (United States)

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

2013-03-01

Bioavailability is a key step in ensuring bioefficacy of bioactive food compounds or oral drugs. Bioavailability is a complex process involving several different stages: liberation, absorption, distribution, metabolism and elimination phases (LADME). Bioactive food compounds, whether derived from various plant or animal sources, need to be bioavailable in order to exert any beneficial effects. Through a better understanding of the digestive fate of bioactive food compounds we can impact the promotion of health and improvement of performance. Many varying factors affect bioavailability, such as bioaccessibility, food matrix effect, transporters, molecular structures and metabolizing enzymes. Bioefficacy may be improved through enhanced bioavailability. Therefore, several technologies have been developed to improve the bioavailability of xenobiotics, including structural modifications, nanotechnology and colloidal systems. Due to the complex nature of food bioactive compounds and also to the different mechanisms of absorption of hydrophilic and lipophilic bioactive compounds, unravelling the bioavailability of food constituents is challenging. Among the food sources discussed during this review, coffee, tea, citrus fruit and fish oil were included as sources of food bioactive compounds (e.g. (poly)phenols and polyunsaturated fatty acids (PUFAs)) since they are examples of important ingredients for the food industry. Although there are many studies reporting on bioavailability and bioefficacy of these bioactive food components, understanding their interactions, metabolism and mechanism of action still requires extensive work. This review focuses on some of the major factors affecting the bioavailability of the aforementioned bioactive food compounds. © 2012 Nestec S. A.. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

Bioavailability of nanoparticulate hematite to Arabidopsis thaliana

International Nuclear Information System (INIS)

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

2013-01-01

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

Improved Chromatographic Bioavailability Estimations

National Research Council Canada - National Science Library

Dorsey, John

1996-01-01

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

Evaluation of Iodine Bioavailability in Seaweed Using in Vitro Methods.

Science.gov (United States)

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

2017-09-27

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

Micronutrient bioavailability: Dietary Reference Intakes and a future perspective1234

Science.gov (United States)

2010-01-01

This article provides a review of how the challenge of bioavailability was approached in establishing the Dietary Reference Intakes, with a special focus on folic acid, vitamin B-12, β-carotene, iron, selenium, and zinc, the targeted micronutrients for this workshop. In a future perspective, the necessity of having a clear working definition of bioavailability is emphasized. The bioavailability of micronutrients should be considered, with advantage, under subheadings determined by the broad factors that affect bioavailability. Special emphasis is given to giving greater and specific attention to factors involved in the maintenance of homeostasis. These factors, it is argued, are best considered separately from even a broad definition of bioavailability and have the potential to provide new insights into some micronutrient requirements. PMID:20200261

On definition and use of the term bioavailability.

Science.gov (United States)

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

1994-10-01

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

The effect of dietary factors on strawberry anthocyanins oral bioavailability.

Science.gov (United States)

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

2017-11-15

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

Bioavailability of syrup and tablet formulations of cefetamet pivoxil.

Science.gov (United States)

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

1993-12-01

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

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.

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...

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

OpenAIRE

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

2013-01-01

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

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

Science.gov (United States)

Ahmed, Shiek S S J; Ramakrishnan, V

2012-01-01

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

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

International Nuclear Information System (INIS)

Liang Xianwei; Zhu Shuzhen; Chen Peng; Zhu Lingyan

2010-01-01

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

ASSESSING SOIL ARSENIC BIOAVAILABILITY IN THE LABORATORY MOUSE

Science.gov (United States)

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

Candesartan cilexetil loaded nanodelivery systems for improved oral bioavailability.

Science.gov (United States)

Dudhipala, Narendar; Veerabrahma, Kishan

2017-02-01

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

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

NARCIS (Netherlands)

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

2000-01-01

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

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

Directory of Open Access Journals (Sweden)

Petruzzelli G.

2013-04-01

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

Nitric oxide bioavailability dysfunction involves in atherosclerosis.

Science.gov (United States)

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

2018-01-01

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

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

Science.gov (United States)

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

2018-05-16

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

Bioavailability enhancement of atovaquone using hot melt extrusion technology.

Science.gov (United States)

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

2016-04-30

Emerging parasite resistance and poor oral bioavailability of anti-malarials are the two cardinal issues which hinder the clinical success of malaria chemotherapy. Atovaquone-Proguanil is a WHO approved fixed dose combination used to tackle the problem of emerging resistance. However, Atovaquone is a highly lipophilic drug having poor aqueous solubility (less than 0.2 μg/ml) thus reducing its oral bioavailability. The aim of the present investigation was to explore hot melt extrusion (HME) as a solvent-free technique to enhance solubility and oral bioavailability of Atovaquone and to develop an oral dosage form for Atovaquone-Proguanil combination. Solid dispersion of Atovaquone was successfully developed using HME. The solid dispersion was characterized for DSC, FTIR, XRD, SEM, and flow properties. It was filled in size 2 hard gelatin capsules. The formulation showed better release as compared to Malarone® tablets, and 3.2-fold and 4.6-fold higher bioavailability as compared to Malarone® tablets and Atovaquone respectively. The enhanced bioavailability also resulted in 100% anti-malarial activity in murine infection model at 1/8(th) therapeutic dose. Thus the developed methodology shows promising potential to solve the problems associated with Atovaquone therapy, namely its high cost and poor oral bioavailability, resulting in increased therapeutic efficacy of Atovaquone. Copyright © 2016 Elsevier B.V. All rights reserved.

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-07-15

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

Bioavailability of glucosinolates and their breakdown products

DEFF Research Database (Denmark)

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

2016-01-01

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

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

DEFF Research Database (Denmark)

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

2014-01-01

Bioavailability of Me-ENMs to aquatic organisms links their release into the environment to ecological implications. Close examination shows some important differences in the conceptual models that define bioavailability for metals and Me-ENMs. Metals are delivered to aquatic animals from Me......-ENMs via water, ingestion, and incidental surface exposure. Both metal released from the Me-ENM and uptake of the nanoparticle itself contribute to bioaccumulation. Some mechanisms of toxicity and some of the metrics describing exposure may differ from metals alone. Bioavailability is driven by complex...... interaction of particle attributes, environmental transformations, and biological traits. Characterization of Me-ENMs is an essential part of understanding bioavailability and requires novel methodologies. The relative importance of the array of processes that could affect Me-ENM bioavailability remains...

Enhanced bioavailability of opiates after intratracheal administration

International Nuclear Information System (INIS)

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

1986-01-01

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

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

Science.gov (United States)

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

2018-01-01

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

Phase behavior and oral bioavailability of amorphous Curcumin.

Science.gov (United States)

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

2012-08-30

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

Pharmacokinetics and Bioavailability of Inhaled Esketamine in Healthy Volunteers.

Science.gov (United States)

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

2017-10-01

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

Protein and amino acid bioavailability estimates for canine foods

NARCIS (Netherlands)

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

2015-01-01

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

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

Directory of Open Access Journals (Sweden)

C. S. Hassler

2009-10-01

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

Improved oral bioavailability of probucol by dry media-milling.

Science.gov (United States)

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

2017-09-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

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

Science.gov (United States)

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

2013-01-23

The aim of this study was to gain understanding about the effects of different solid-state forms of a poorly water-soluble piroxicam on drug dissolution and oral bioavailability in rats. Three different solid-state forms of piroxicam were studied: anhydrate I (AH), monohydrate (MH), and amorphous form in solid dispersion (SD). In addition, the effect of a new polymeric excipient Soluplus® (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer) on oral bioavailability of piroxicam was investigated. Significant differences in the dissolution and oral bioavailability were found between the solid-state forms of piroxicam. Amorphous piroxicam in SD showed the fastest dissolution in vitro and a solid-state transformation to MH in the dissolution medium. Despite the presence of solid-state transformation, SD exhibited the highest rate and extent of oral absorption in rats. Oral bioavailability of other two solid-state forms decreased in the order AH and MH. The use of Soluplus® was found to enhance the dissolution and oral bioavailability of piroxicam in rats. The present study shows the importance of solid-state form selection for oral bioavailability of a poorly water-soluble drug. Copyright © 2012 Elsevier B.V. All rights reserved.

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

International Nuclear Information System (INIS)

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

2010-01-01

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

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

Science.gov (United States)

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

2016-03-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-05-15

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

A Review of Mercury Bioavailability in Humans and Fish.

Science.gov (United States)

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

2017-02-10

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

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...

Bioavailability of cadmium from linseed and cocoa

DEFF Research Database (Denmark)

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

2014-01-01

The exposure of the European population to cadmium from food is high compared with the tolerable weekly intake of 2.5 μg/kg bodyweight set by EFSA in 2009. Only few studies on the bioavailability of cadmium from different food sources has been performed but this information in very important...... for the food authorities in order to give correct advises to the population. The aim of this study was to investigate the bioavailability of cadmium from whole linseed, crushed linseed, cocoa and cadmium chloride in rats. An experiment where 40 rats were divided into 4 groups and a control group and dosed...... be measured in the kidney compared to the calculated total intake was as follows: Control 2.0 %, Crushed linseed 0.9 %, whole linseed, 1.5 %, cocoa 0.7 % and CdCl2 4.6 %. Based on this study it could not be concluded that the bioavailability in rats form whole linseed is lower that for crushed linseed...

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

Science.gov (United States)

You, Jing; Li, Huizhen

2017-12-13

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

Improved bioavailability

Directory of Open Access Journals (Sweden)

Nadia M. Morsi

2016-09-01

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

Assessing the bioavailability and bioaccessibility of metals and metalloids.

Science.gov (United States)

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

2015-06-01

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

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...

Marine lipids and the bioavailability of omega-3 fatty acids

DEFF Research Database (Denmark)

Mu, Huiling; Müllertz, Anette

2015-01-01

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

Iron bioavailability: UK Food Standards Agency workshop report.

Science.gov (United States)

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

2006-11-01

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

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

International Nuclear Information System (INIS)

Chakraborty, Parthasarathi; Ramteke, Darwin; Chakraborty, Sucharita

2015-01-01

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

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

DEFF Research Database (Denmark)

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

2000-01-01

A previously described bioassay using a mer-lux gene fusion for detection of bioavailable mercury was applied for the estimation of the bioavailable fraction of mercury in soil. The bioavailable fraction is defined here as being part of the water leachable fraction. Due to masking of light emission...... responses. The utility of the mer-lux biosensor assay was tested by relating measurements of bioavailable and total mercury to the response of the soil microbial community to mercury exposure. Two different soil types (an agricultural and a beech forest soil) were spiked with 2.5 µg Hg(II) g-1 in microcosms...... in resistance or diversity. This study showed that the bioassay using the mer-lux biosensor is a useful and sensitive tool for estimation of bioavailable mercury in soil....

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

Science.gov (United States)

Sieger, P; Cui, Y; Scheuerer, S

2017-07-15

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

A Review of Mercury Bioavailability in Humans and Fish

Directory of Open Access Journals (Sweden)

Mark A. Bradley

2017-02-01

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

Synthetic and tomato-based lycopene have identical bioavailability in humans

NARCIS (Netherlands)

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

2003-01-01

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

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

Food synergies for improving bioavailability of micronutrients from plant foods.

Science.gov (United States)

Nair, K Madhavan; Augustine, Little Flower

2018-01-01

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

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

International Nuclear Information System (INIS)

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

1993-01-01

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

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

Science.gov (United States)

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

2017-07-01

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

Bacterial metal resistance genes and metal bioavailability in contaminated sediments

International Nuclear Information System (INIS)

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

2014-01-01

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

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

Science.gov (United States)

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

2017-07-19

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

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

NARCIS (Netherlands)

Sips AJAM; Eijkeren JCH van; LBO

1996-01-01

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

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

Science.gov (United States)

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

2018-02-01

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

Bioavailability of lead in rats fed human diets

International Nuclear Information System (INIS)

Kostial, K.; Kello, D.

1979-01-01

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

Bioavailability and Pharmacodynamics of Promethazine in Human Subjects

Science.gov (United States)

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

2000-01-01

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

In vitro evaluation of dietary compounds to reduce mercury bioavailability.

Science.gov (United States)

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

2018-05-15

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

Bioavailability of Metal Ions and Evolutionary Adaptation

Directory of Open Access Journals (Sweden)

Rolando P. Hong Enriquez

2012-10-01

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

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

Science.gov (United States)

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

2017-10-01

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

Origins and bioavailability of dissolved organic matter in groundwater

Science.gov (United States)

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

2015-01-01

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

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

Science.gov (United States)

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

2017-10-01

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

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.

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

Science.gov (United States)

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

2016-02-01

Bioavailability of metals to aquatic organisms can be considered to be a combination of the physicochemical factors governing metal behavior and the specific pathophysiological characteristics of the organism's biological receptor. Effectively this means that a measure of bioavailability will reflect the exposures that organisms in the water column actually "experience". This is important because it has long been established that measures of total metal in waters have limited relevance to potential environmental risk. The concept of accounting for bioavailability in regard to deriving and implementing environmental water quality standards is not new, but the regulatory reality has lagged behind the development of scientific evidence supporting the concept. Practical and technical reasons help to explain this situation. For example, concerns remain from regulators and the regulated that the efforts required to change existing systems of metal environmental protection that have been in place for over 35 yr are so great as not to be commensurate with likely benefits. However, more regulatory jurisdictions are now considering accounting for metal bioavailability in assessments of water quality as a means to support evidence-based decision-making. In the past decade, both the US Environmental Protection Agency and the European Commission have established bioavailability-based standards for metals, including Cu and Ni. These actions have shifted the debate toward identifying harmonized approaches for determining when knowledge is adequate to establish bioavailability-based approaches and how to implement them. © 2016 SETAC.

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

International Nuclear Information System (INIS)

Ahmad, T.; Bilal, R.

2001-01-01

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

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

International Nuclear Information System (INIS)

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

2011-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-04-15

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

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

Science.gov (United States)

Petruzzelli, Gianniantonio; Pedron, Francesca; Pezzarossa, Beatrice

2013-04-01

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

Bioavailability of contaminants estimated from uptake rates into soil invertebrates

International Nuclear Information System (INIS)

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

2005-01-01

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

EFFECT OF SOIL PROPERTIES ON LEAD BIOAVAILABILITY AND TOXCITY TO EARTHWORMS

Science.gov (United States)

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

Red wine is a poor source of bioavailable flavonols in men

NARCIS (Netherlands)

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

2001-01-01

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

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

Science.gov (United States)

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

2014-01-01

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

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.

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

Science.gov (United States)

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

2012-11-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-10-15

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

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

Science.gov (United States)

Sen Gupta, Surashree; Ghosh, Mahua

2017-10-01

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

Dietary factors that affect carotenoid bioavailability

NARCIS (Netherlands)

Hof, van het K.H.

1999-01-01

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

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

Science.gov (United States)

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

2015-11-01

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

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

Science.gov (United States)

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

2010-07-01

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

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

Science.gov (United States)

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

2016-02-17

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

Mobility and Bioavailability of Radionuclides in Soils

International Nuclear Information System (INIS)

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

2016-01-01

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

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

International Nuclear Information System (INIS)

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

2014-01-01

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

Rapid screening assay for calcium bioavailability studies

International Nuclear Information System (INIS)

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

1986-01-01

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

Bioavailability in rats of metal adsorbed to soils

International Nuclear Information System (INIS)

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

1990-01-01

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

Bioavailability of metals-trace in sediments: a review

International Nuclear Information System (INIS)

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

2014-01-01

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

Solubility and bioavailability of stabilized amorphous calcium carbonate.

Science.gov (United States)

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

2011-02-01

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

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

International Nuclear Information System (INIS)

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

2003-01-01

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

BIOAVAILABILITY AND PHARMACOKINETICS OF NORFLOXACIN AFTER INTRAMUSCULAR ADMINISTRATION IN GOATS

Directory of Open Access Journals (Sweden)

WAJEEHA, F. H. KHAN AND I. JAVED

2006-01-01

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

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

Science.gov (United States)

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

2002-01-17

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

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

Directory of Open Access Journals (Sweden)

Saurabh Rajpal

2018-05-01

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

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

Science.gov (United States)

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

2018-05-01

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

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

International Nuclear Information System (INIS)

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

2005-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2005-07-15

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

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

Science.gov (United States)

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

2015-06-01

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

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.

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

Science.gov (United States)

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

2016-02-01

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

Bioavailability and variability of biphasic insulin mixtures

DEFF Research Database (Denmark)

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

2012-01-01

Absorption of subcutaneously administered insulin is associated with considerable variability. Some of this variability was quantitatively explained for both soluble insulin and insulin suspensions in a recent contribution to this journal (Søeborg et al., 2009). In the present article......, the absorption kinetics for mixtures of insulins is described. This requires that the bioavailability of the different insulins is considered. A short review of insulin bioavailability and a description of the subcutaneous depot thus precede the presentation of possible mechanisms associated with subcutaneous...... insulin degradation. Soluble insulins are assumed to be degraded enzymatically in the subcutaneous tissue. Suspended insulin crystals form condensed heaps that are assumed to be degraded from their surface by invading macrophages. It is demonstrated how the shape of the heaps affects the absorption...

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

Science.gov (United States)

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

2017-03-04

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

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

NARCIS (Netherlands)

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

2018-01-01

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

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

Science.gov (United States)

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

2017-01-01

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

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

Science.gov (United States)

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

2013-10-09

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

Bioavailability and stability of erythromycin delayed release tablets.

Science.gov (United States)

Ogwal, S; Xide, T U

2001-12-01

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

Stable isotope studies of nicotine kinetics and bioavailability

International Nuclear Information System (INIS)

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

1991-01-01

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

Influence of ageing on zinc bioavailability in soils

Energy Technology Data Exchange (ETDEWEB)

Lock, K.; Janssen, C.R

2003-12-01

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

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.

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

NARCIS (Netherlands)

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

2004-01-01

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

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.

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

International Nuclear Information System (INIS)

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

2007-01-01

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

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

Science.gov (United States)

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

2016-01-01

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

Considering bioavailability in the remediation of heavy metal contaminated sites

Directory of Open Access Journals (Sweden)

Leita L.

2013-04-01

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

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.

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

Science.gov (United States)

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

2016-01-01

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

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

Science.gov (United States)

2010-04-01

... vivo bioavailability study. 320.27 Section 320.27 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE BIOAVAILABILITY AND BIOEQUIVALENCE REQUIREMENTS Procedures for Determining the Bioavailability or Bioequivalence of Drug Products § 320.27...

Enhancement of Solubility and Bioavailability of Candesartan ...

African Journals Online (AJOL)

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

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

Science.gov (United States)

Aungst, Bruce J

2017-04-01

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

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

Science.gov (United States)

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

2002-01-01

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

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

International Nuclear Information System (INIS)

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

2014-01-01

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

Bioavailability and Pharmacokinetics of Oral Cocaine in Humans.

Science.gov (United States)

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

2018-06-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

International Nuclear Information System (INIS)

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

2010-01-01

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

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.

Bioavailability of trans-resveratrol from red wine in humans.

Science.gov (United States)

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

2005-05-01

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

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

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

OpenAIRE

SUMITA ELENDRAN

2017-01-01

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

Relating Bioavailability Parameters to the Sorbent Characteristics of PAH Polluted Soils

DEFF Research Database (Denmark)

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

2015-01-01

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

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

International Nuclear Information System (INIS)

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

2012-01-01

Although soil characteristics modulate metal mobility and bioavailability to organisms, they are often ignored in the risk assessment of metal transfer. This paper aims to determine the ability of chemical methods to assess and predict cadmium (Cd), lead (Pb) and zinc (Zn) environmental bioavailability to the land snail Cantareus aspersus. Snails were exposed in the laboratory for 28 days to 17 soils from around a former smelter. The soils were selected for their range of pH, organic matter, clay content, and Cd, Pb and Zn concentrations. The influence of soil properties on environmental availability (estimated using HF-HClO 4 , EDTA, CaCl 2 , NH 4 NO 3 , NaNO 3 , free ion activity and total dissolved metal concentration in soil solution) and on environmental bioavailability (modelled using accumulation kinetics) was identified. Among the seven chemical methods, only the EDTA and the total soil concentration can be used to assess Cd and Pb environmental bioavailability to snails (r² adj = 0.67 and 0.77, respectively). For Zn, none of the chemical methods were suitable. Taking into account the influence of the soil characteristics (pH and CEC) allows a better prediction of Cd and Pb environmental bioavailability (r² adj = 0.82 and 0.83, respectively). Even though alone none of the chemical methods tested could assess Zn environmental bioavailability to snails, the addition of pH, iron and aluminium oxides allowed the variation of assimilation fluxes to be predicted. A conceptual and practical method to use soil characteristics for risk assessment is proposed based on these results. We conclude that as yet there is no universal chemical method to predict metal environmental bioavailability to snails, and that the soil factors having the greatest impact depend on the metal considered. - Highlights: ► New approach to identify chemical methods able to predict metal bioavailability to snails. ► Bioavailability of cadmium, lead and zinc to snails was determined by

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-08-01

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

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

Science.gov (United States)

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

2017-08-15

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

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

Science.gov (United States)

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

2017-12-01

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

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

Science.gov (United States)

Wang, D. Y.

2015-12-01

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

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

International Nuclear Information System (INIS)

Zheng Hui; Zhen Rong; Niu Huisheng; Li Huaifen

2004-01-01

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

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

International Nuclear Information System (INIS)

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

2006-01-01

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

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

Science.gov (United States)

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

2017-06-13

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

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

International Nuclear Information System (INIS)

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

2017-01-01

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

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

Science.gov (United States)

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

2008-06-01

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

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

Science.gov (United States)

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

2017-12-01

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

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

Science.gov (United States)

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

2008-01-01

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

Bioavailability of four oral Coenzyme Q formulations in healthy volunteers

DEFF Research Database (Denmark)

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

1994-01-01

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

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.

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

Science.gov (United States)

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

2018-04-21

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

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

Science.gov (United States)

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

2017-06-01

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

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

Science.gov (United States)

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

2017-07-01

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

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

International Nuclear Information System (INIS)

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

1994-01-01

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

Development of Bioavailability Adjustment Factors: A Feasibility Study

National Research Council Canada - National Science Library

Rembish, Steve

2000-01-01

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

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.

Bioavailability of mercury in East Fork Poplar Creek soils

International Nuclear Information System (INIS)

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

1995-05-01

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

Antimony bioavailability in mine soils

International Nuclear Information System (INIS)

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

2003-01-01

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

Bioavailability of diclofenac potassium at low doses

Science.gov (United States)

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

2005-01-01

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

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...

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

International Nuclear Information System (INIS)

Zhong Huan; Kraemer, Lisa; Evans, Douglas

2013-01-01

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

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

International Nuclear Information System (INIS)

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

2017-01-01

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

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

Science.gov (United States)

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

2017-07-01

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

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

Science.gov (United States)

Ringling, Christiane; Rychlik, Michael

2017-09-01

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

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

Science.gov (United States)

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

2018-01-01

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

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

Science.gov (United States)

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

2011-02-14

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

Influence of deposition and spray pattern of nasal powders on insulin bioavailability.

Science.gov (United States)

Pringels, E; Callens, C; Vervaet, C; Dumont, F; Slegers, G; Foreman, P; Remon, J P

2006-03-09

The influence of the deposition pattern and spray characteristics of nasal powder formulations on the insulin bioavailability was investigated in rabbits. The formulations were prepared by freeze drying a dispersion containing a physical mixture of drum dried waxy maize starch (DDWM)/Carbopol 974P (90/10, w/w) or a spray-dried mixture of Amioca starch/Carbopol 974P (25/75, w/w). The deposition in the nasal cavity of rabbits and in a silicone human nose model after actuation of three nasal delivery devices (Monopowder, Pfeiffer and experimental system) was compared and related to the insulin bioavailability. Posterior deposition of the powder formulation in the nasal cavity lowered the insulin bioavailability. To study the spray pattern, the shape and cross-section of the emitted powder cloud were analysed. It was concluded that the powder bulk density of the formulation influenced the spray pattern. Consequently, powders of different bulk density were prepared by changing the solid fraction of the freeze dried dispersion and by changing the freezing rate during freeze drying. After nasal delivery of these powder formulations no influence of the powder bulk density and of the spray pattern on the insulin bioavailability was observed.

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...

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

Science.gov (United States)

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

2018-05-17

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

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

OpenAIRE

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

2016-01-01

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

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

Science.gov (United States)

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

2018-03-08

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

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

Science.gov (United States)

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

2016-12-01

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

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

Science.gov (United States)

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

2017-09-05

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

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

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

International Nuclear Information System (INIS)

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

2012-01-01

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

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

Science.gov (United States)

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

2008-05-30

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

Bioavailability and bioaccumulation of metal-based engineered nanomaterials in aquatic environments: concepts and processes: chapter 5

Science.gov (United States)

Luoma, Samuel N.; Khan, Farhan R.; Croteau, Marie-Noële

2014-01-01

Bioavailability of Me-ENMs to aquatic organisms links their release into the environment to ecological implications. Close examination shows some important differences in the conceptual models that define bioavailability for metals and Me-ENMs. Metals are delivered to aquatic animals from Me-ENMs via water, ingestion, and incidental surface exposure. Both metal released from the Me-ENM and uptake of the nanoparticle itself contribute to bioaccumulation. Some mechanisms of toxicity and some of the metrics describing exposure may differ from metals alone. Bioavailability is driven by complex interaction of particle attributes, environmental transformations, and biological traits. Characterization of Me-ENMs is an essential part of understanding bioavailability and requires novel methodologies. The relative importance of the array of processes that could affect Me-ENM bioavailability remains poorly known, but new approaches and models are developing rapidly. Enough is known, however, to conclude that traditional approaches to exposure assessment for metals would not be adequate to assess risks from Me-ENMs.

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

Science.gov (United States)

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

2016-12-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1997-12-31

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

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

Science.gov (United States)

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

2017-08-30

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

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

Science.gov (United States)

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

2014-01-01

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

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

Science.gov (United States)

2016-11-01

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

Heat-treated hull flour does not affect iron bioavailability in rats.

Science.gov (United States)

Martino, Hércia Stampini Duarte; Carvalho, Ariela Werneck de; Silva, Cassiano Oliveira da; Dantas, Maria Inês de Souza; Natal, Dorina Isabel Gomes; Ribeiro, Sônia Machado Rocha; Costa, Neuza Maria Brunoro

2011-06-01

In this study the chemical composition and iron bioavailability of hull and hull-less soybean flour from the new cultivar UFVTN 105AP was evaluated. The hemoglobin depletion-repletion method was used in Wistar rats. Soybean hull flour presented 37% more total dietary fiber and higher content of iron than hull-less soybean flour. The phytate:iron molar ratio, however, was 2-fold lower in the soybean hull flour in compared to the hull-less soybean flour. Animals fed soybean hull flour presented hemoglobin gains similar to those of the control diet group (p > 0.05). The Relative Biological Values of hull and hull-less soybean flour were 68.5% and 67.1%, respectively, compared to the control group. Heat-treated soybean hull flour (150 degrees C/30 minutes) showed high content of iron and low phytate, which favors the iron bioavailability. Thus, the soybean hull flour is a better source of dietary fiber and iron than hull-less soybean flour at comparable bioavailabilities.

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

International Nuclear Information System (INIS)

Jonge, H. de; Verstraten, J.M.

1995-01-01

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 P 2 O 7 4- (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

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

Organoclays reduce arsenic bioavailability and bioaccessibility in contaminated soils

Energy Technology Data Exchange (ETDEWEB)

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

2012-05-15

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

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

Science.gov (United States)

2010-04-01

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

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

Science.gov (United States)

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

2011-02-01

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

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...

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

Science.gov (United States)

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

2018-01-01

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

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

Science.gov (United States)

Schweiggert, R M; Carle, R

2017-06-13

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

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

International Nuclear Information System (INIS)

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

2002-01-01

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

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

Science.gov (United States)

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

2015-11-01

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

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

Science.gov (United States)

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

2013-07-14

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

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

OpenAIRE

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

2018-01-01

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

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...

From bioavailability science to regulation of organic chemicals

NARCIS (Netherlands)

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

2015-01-01

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

Bioavailability is improved by enzymatic modification of the citrus flavonoid hesperidin in humans

DEFF Research Database (Denmark)

Nielsen, Inge Lise F; Chee, Winnie S S; Poulsen, Lea

2006-01-01

Hesperidin is the predominant polyphenol consumed from citrus fruits and juices. However, hesperidin is proposed to have limited bioavailability due to the rutinoside moiety attached to the flavonoid. The aim of this study was to demonstrate in human subjects that the removal of the rhamnose group...... to yield the corresponding flavonoid glucoside (i.e., hesperetin-7-glucoside) will improve the bioavailability of the aglycone hesperetin. Healthy volunteers (n=16) completed the double-blind, randomized, crossover study. Subjects randomly consumed hesperetin equivalents supplied as orange juice...... that the bioavailability of hesperidin was modulated by enzymatic conversion to hesperetin-7-glucoside, thus changing the absorption site from the colon to the small intestine. This may affect future interventions concerning the health benefits of citrus flavonoids....

Phenazopyridine-phthalimide nano-cocrystal: Release rate and oral bioavailability enhancement.

Science.gov (United States)

Huang, Yu; Li, Jin-Mei; Lai, Zhi-Hui; Wu, Jun; Lu, Tong-Bu; Chen, Jia-Mei

2017-11-15

Both cocrystal and nanocrystal technologies have been widely used in the pharmaceutical development for poorly soluble drugs. However, the synergistic effects due to the integration of these two technologies have not been well investigated. The aim of this study is to develop a nano-sized cocrystal of phenazopyridine (PAP) with phthalimide (PI) to enhance the release rate and oral bioavailability of PAP. A PAP-PI nano-cocrystal with particle diameter of 21.4±0.1nm was successfully prepared via a sonochemical approach and characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and dynamic light scattering (DLS) analysis. An in vitro release study revealed a significant release rate enhancement for PAP-PI nano-cocrystal as compared to PAP-PI cocrystal and PAP hydrochloride salt. Further, a comparative oral bioavailability study in rats indicated significant improvement in C max and oral bioavailability (AUC 0-∞ ) by 1.39- and 2.44-fold, respectively. This study demonstrated that this novel nano-cocrystal technology can be a new promising option to improve release rate and absorption of poorly soluble compounds in the pharmaceutical industry. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Improving oral bioavailability of resveratrol by a UDP-glucuronosyltransferase inhibitory excipient-based self-microemulsion.

Science.gov (United States)

Yang, Fei-Fei; Zhou, Jing; Hu, Xiao; Cong, Zhao-Qing; Liu, Chun-Yu; Pan, Rui-Le; Chang, Qi; Liu, Xin-Min; Liao, Yong-Hong

2018-03-01

Self-microemulsifying (SME) drug delivery system has been developed to increase oral bioavailabilities, and inhibitory excipients are capable of improving oral bioavailability by inhibiting enzyme mediated intestinal metabolism. However, the potential of enzyme inhibitory excipients containing SME in boosting resveratrol bioavailability remains largely uninvestigated. In this study, we set out to prepare SME-1 with UGT inhibitory excipients (excipients without inhibitory activities named SME-2 as control) to increase the bioavailability of RES by inhibiting intestinal metabolism. Results demonstrated that similar physicochemical properties such as size, polydistribution index and in vitro release, cellular uptake and permeability in Caco-2 cells as well as in vivo lymphatic distribution between inhibitory SME-1 and non-inhibitory SME-2 were observed. In vivo study demonstrated that the molar ratios of RES-G/RES were 7.25±0.48 and 5.06±2.42 for free drug and SME-2, respectively, and the molar ratio decreased to 0.36±0.10 in SME-1 group. Pharmacokinetic study confirmed that the inhibitory excipients containing SME demonstrated potential in increasing bioavailability of RES from 6.5% for the free RES and 12.9% for SME-2 to 76.1% in SME-1 through modulating the glucuronidation by UGT inhibitory excipients. Copyright © 2018 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

Singh, Poonam; Prasad, Surendra; Aalbersberg, William

2016-09-15

The present study reports contents and the bioavailability of Fe and Zn from 25 selected raw and cooked food samples. The results showed highest variation of Fe content in raw food samples ranging from 2.19 ± 0.04 to 0.93 ± 0.03 mg/100g in legumes. The raw black eye bean, cheese and fish showed high Zn content up to 8.85 ± 0.01, 12.93 ± 0.26 and 172.03 ± 5.09 mg/100g, respectively. Pulses and cereals showed high level of ionizable Fe. Zn bioavailability was quite low in cereals as compared to pulses; 4.02% in yellow split to 17.40% in Bengal gram. Zn bioavailability of 17.40% is in cheese. Fe bioavailability is high in cooked rice 160.60%, white bread 428.30% and milk powder 241.67% showing that Fe bioavailability increased after cooking whereas the lowest in fish 0.84%. The multivariate and cluster analysis categorized studied foods into two main groups. Copyright © 2016 Elsevier Ltd. All rights reserved.

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...

Atovaquone oral bioavailability enhancement using electrospraying technology.

Science.gov (United States)

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

2018-01-01

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

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

Science.gov (United States)

Rosado, Daniel; Usero, José; Morillo, José

2016-06-01

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

Extraction, bioavailability, and bioefficacy of capsaicinoids

OpenAIRE

Muwen Lu; Chi-Tang Ho; Qingrong Huang

2017-01-01

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

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

Science.gov (United States)

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

2017-12-01

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

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

Science.gov (United States)

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

2017-07-01

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

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.

Production, Characterization and Evaluation of Kaempferol Nanosuspension for Improving Oral Bioavailability.

Science.gov (United States)

Qian, Yew S; Ramamurthy, Srinivasan; Candasamy, Mayuren; Shadab, Md; Kumar, Ravindran H; Meka, Venkata S

2016-01-01

Kaempferol has a large particle size and poor water solubility, leading to poor oral bioavailability. The present work aimed to develop a kaempferol nanosuspension (KNS) to improve pharmacokinetics and absolute bioavailability. A nanosuspension was prepared using high pressure homogenization (HPH) techniques. The physico-chemical properties of the kaempferol nanosuspension (KNS) were characterized using photon correlation spectroscopy (PCS), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and x-ray diffractometry (XRD). A reversephase high performance liquid chromatography (RP-HPLC) method for the analysis of the drug in rat plasma was developed and validated as per ICH guidelines. In vivo pharmacokinetic parameters of oral pure kaempferol solution, oral kaempferol nanosuspension and intravenous pure kaempferol were assessed in rats. The kaempferol nanosuspension had a greatly reduced particle size (426.3 ± 5.8 nm), compared to that of pure kaempferol (1737 ± 129 nm). The nanosuspension was stable under refrigerated conditions. No changes in physico-chemical characteristics were observed. In comparison to pure kaempferol, kaempferol nanosuspension exhibited a significantly (Pkaempferol. These results demonstrate enhanced oral bioavailability of kaempferol when formulated as a nanosuspension.

Saccharides enhance iron bioavailability to Southern Ocean phytoplankton

NARCIS (Netherlands)

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

2011-01-01

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

Rumen microorganisms decrease bioavailability of inorganic selenium supplements

Science.gov (United States)

Despite the availaility of selenium (Se)-enriched trace mineral supplements, we have observed low Se status in cattle and sheep offered traditional inorganic Se supplements. Reasons for this may include inadequate intake or low bioavailability of inorganic Se sources. The objective of this study w...

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

Science.gov (United States)

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

2016-09-30

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-10-15

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

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

Science.gov (United States)

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

2007-01-01

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

Does ascorbic acid supplementation affect iron bioavailability in rats fed micronized dispersible ferric pyrophosphate fortified fruit juice?

Science.gov (United States)

Haro-Vicente, Juan Francisco; Pérez-Conesa, Darío; Rincón, Francisco; Ros, Gaspar; Martínez-Graciá, Carmen; Vidal, Maria Luisa

2008-12-01

Food iron (Fe) fortification is an adequate approach for preventing Fe-deficiency anemia. Poorly water-soluble Fe compounds have good sensory attributes but low bioavailability. The reduction of the particle size of Fe fortificants and the addition of ascorbic acid might increase the bioavailability of low-soluble compounds. The present work aims to compare the Fe absorption and bioavailability of micronized dispersible ferric pyrophosphate (MDFP) (poorly soluble) to ferrous sufate (FS) (highly soluble) added to a fruit juice in presence or absence of ascorbic acid (AA) by using the hemoglobin repletion assay in rats. After a hemoglobin depletion period, four fruit juices comprised of (1) FS, (2) MDFP, (3) FS + AA, (4) MDFP + AA were produced and administered to a different group of rats (n = 18) over 21 days. During the repletion period, Fe balance, hemoglobin regeneration efficiency (HRE), relative bioavailability (RBV) and Fe tissue content were determined in the short, medium and long term. Fe absorption and bioavailability showed no significant differences between fortifying the fruit juice with FS or MDFP. The addition of AA to the juice enhanced Fe absorption during the long-term balance study within the same Fe source. HRE and Fe utilization increased after AA addition in both FS and MDFP groups in every period. Fe absorption and bioavailability from MDFP were comparable to FS added to a fruit juice in rats. Further, the addition of AA enhanced Fe absorption in the long term, as well as Fe bioavailability throughout the repletion period regardless of the Fe source employed.

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

Science.gov (United States)

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

2018-01-01

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

Excipient-mediated alteration in drug bioavailability in the rat depends on the sex of the animal.

Science.gov (United States)

Mai, Yang; Afonso-Pereira, Francisco; Murdan, Sudaxshina; Basit, Abdul W

2017-09-30

The pharmaceutical excipient, polyethylene glycol 400 (PEG 400), unexpectedly alters the bioavailability of the BCS class III drug ranitidine in a sex-dependent manner. As ranitidine is a substrate for the efflux transporter P-glycoprotein (P-gp), we hypothesized that the sex-related influence could be due to interactions between PEG 400 and P-gp. In this study, we tested this hypothesis by: i) measuring the influence of PEG 400 on the oral bioavailability of another P-gp substrate (ampicillin) and of a non-P-gp substrate (metformin); and ii) measuring the effect of PEG 400 on drug bioavailability in the presence of a P-gp inhibitor (cyclosporine A) in male and female rats. We found that PEG 400 significantly increased (pbioavailability of ampicillin (the P-gp substrate) in male rats, but not in female ones. In contrast, PEG 400 had no influence on the bioavailability of the non-P-gp substrate, metformin in male or female rats. Inhibition of P-gp by oral pre-treatment with cyclosporine A increased the bioavailability of the P-gp substrates (ampicillin and ranitidine) in males and females (pbioavailability of metformin in either male or female rats. These results prove the hypothesis that the sex-specific effect of PEG 400 on the bioavailability of certain drugs is due to the interaction of PEG 400 with the efflux transporter P-gp. Copyright © 2017 Elsevier B.V. All rights reserved.

Acetylated Hyaluronic Acid: Enhanced Bioavailability and Biological Studies

Directory of Open Access Journals (Sweden)

Carmela Saturnino

2014-01-01

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

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

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Correlation of bioavailability with an acute pharmacological effect or clinical evidence. 320.28 Section 320.28 Food and Drugs FOOD AND DRUG ADMINISTRATION... Correlation of bioavailability with an acute pharmacological effect or clinical evidence. Correlation of in...

Hologram QSAR model for the prediction of human oral bioavailability.

Science.gov (United States)

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

2007-12-15

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

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

Directory of Open Access Journals (Sweden)

Chenguang Li

2017-02-01

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

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

Science.gov (United States)

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

2014-03-01

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

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Speciation and bioavailability of copper in Lake Tjeukemeer

NARCIS (Netherlands)

Verweij, W.

1991-01-01

Chapter 1: introduction

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

Distribution and bioavailability of cadmium in ornithogenic coral-sand sediments of the Xisha archipelago, South China Sea

International Nuclear Information System (INIS)

Liu Xiaodong; Lou Chuangneng; Xu Liqiang; Sun Liguang

2012-01-01

Total cadmium (Cd) concentrations in four ornithogenic coral-sand sedimentary profiles displayed a strong positive correlation with guano-derived phosphorus, but had no correlation with plant-originated organic matter in the top sediments. These results indicate that the total Cd distributions were predominantly controlled by guano input. Bioavailable Cd and zinc (Zn) had a greater input rate in the top sediments with respect to total Cd and total Zn, and a positive correlation with total organic carbon (TOC) derived from plant humus. Multi-regression analysis showed that the total Cd and TOC explained over 80% of the variation of bioavailable Cd, suggesting that both guano and plant inputs could significantly influence the distribution of bioavailable Cd, and that plant biocycling processes contribute more to the recent increase of bioavailable Cd. A pollution assessment indicates that the Yongle archipelago is moderately to strongly polluted with guano-derived Cd. - Guano and plant biocycling processes can exert different influences on the distributions of total Cd and bioavailable Cd in coral-sand ornithogenic sediments.

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

International Nuclear Information System (INIS)

Nakamaru, Yasuo Mitsui; Martín Peinado, Francisco José

2017-01-01

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

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

Science.gov (United States)

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

2016-10-01

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

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

Science.gov (United States)

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

2016-01-01

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

Application of isotope dilution method for measuring bioavailability of organic contaminants sorbed to dissolved organic matter (DOM)

Energy Technology Data Exchange (ETDEWEB)

Delgado-Moreno, Laura, E-mail: laura.delgado@eez.csic.es; Wu, Laosheng; Gan, Jay

2015-08-15

Natural waters such as surface water and sediment porewater invariably contain dissolved organic matter (DOM). Association of strongly hydrophobic contaminants (HOCs) with DOM leads to decreased toxicity and bioavailability, but bioavailability of DOM-sorbed HOCs is difficult to measure. Current methods to estimate bioavailability of HOCs in water are based on only the freely dissolved concentration (C{sub free}). The ignorance of the exchangeable fraction of HOCs sorbed on DOM may result in an underestimation of the toxicity potential of HOCs to aquatic organisms. Here we explore the applicability of an isotope dilution method (IDM) to measuring the desorption fraction of DOM-sorbed pyrene and bifenthrin and determining their exchangeable pool (E) as an approximation of bioavailability. E values, expressed as percentage of the total concentration, ranged between 0.80 and 0.92% for pyrene and 0.74 and 0.85% for bifenthrin, depending primarily on the amount of chemical in the freely dissolved form. However, between 34 and 78% of the DOM-sorbed pyrene was exchangeable. This fraction ranged between 23% and 82% for bifenthrin. The ability of IDM to predict bioavailability was further shown from a significant relationship (r{sup 2} > 0.72, P < 0.0001) between E and bioaccumulation into Daphnia magna. Therefore, IDM may be used to improve the bioavailability measurement and risk assessment of HOCs in aquatic systems.

Application of isotope dilution method for measuring bioavailability of organic contaminants sorbed to dissolved organic matter (DOM)

International Nuclear Information System (INIS)

Delgado-Moreno, Laura; Wu, Laosheng; Gan, Jay

2015-01-01

Natural waters such as surface water and sediment porewater invariably contain dissolved organic matter (DOM). Association of strongly hydrophobic contaminants (HOCs) with DOM leads to decreased toxicity and bioavailability, but bioavailability of DOM-sorbed HOCs is difficult to measure. Current methods to estimate bioavailability of HOCs in water are based on only the freely dissolved concentration (C free ). The ignorance of the exchangeable fraction of HOCs sorbed on DOM may result in an underestimation of the toxicity potential of HOCs to aquatic organisms. Here we explore the applicability of an isotope dilution method (IDM) to measuring the desorption fraction of DOM-sorbed pyrene and bifenthrin and determining their exchangeable pool (E) as an approximation of bioavailability. E values, expressed as percentage of the total concentration, ranged between 0.80 and 0.92% for pyrene and 0.74 and 0.85% for bifenthrin, depending primarily on the amount of chemical in the freely dissolved form. However, between 34 and 78% of the DOM-sorbed pyrene was exchangeable. This fraction ranged between 23% and 82% for bifenthrin. The ability of IDM to predict bioavailability was further shown from a significant relationship (r 2 > 0.72, P < 0.0001) between E and bioaccumulation into Daphnia magna. Therefore, IDM may be used to improve the bioavailability measurement and risk assessment of HOCs in aquatic systems

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

Science.gov (United States)

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

2016-02-01

The effects of 2.8% w/w granulated activated carbon (GAC) and two types of biochar (Burt's and BlueLeaf) on DDT bioavailability in soil (39 μg/g) were investigated using invertebrates (Eisenia fetida), plants (Cucurbita pepo spp. pepo) and a polyoxymethylene (POM) passive sampler method. Biochar significantly reduced DDT accumulation in E. fetida (49%) and showed no detrimental effects to invertebrate health. In contrast, addition of GAC caused significant toxic effects (invertebrate avoidance and decreased weight) and did not significantly reduce the accumulation of DDT into invertebrate tissue. None of the carbon amendments reduced plant uptake of DDT. Bioaccumulation of 4,4'DDT and 4,4'-DDE in plants (C. pepo spp. pepo) and invertebrates (E. fetida) was assessed using bioaccumulation factors (BAFs) and compared to predicted bioavailability using the freely-dissolved porewater obtained from a polyoxymethylene (POM) equilibrium biomimetic method. The bioavailable fraction predicted by the POM samplers correlated well with measured invertebrate uptake (DDT soil contamination levels and the inclusion of field data from a 2.5 μg/g DDT-contaminated site found that these plants exhibit a concentration threshold effect at [DDT](soil) > 10 μg/g. The results of these studies illustrate the importance of including plants in bioavailability studies as the use of carbon materials for in situ contaminant sorption moves from predominantly sediment to soil remediation technologies. Copyright © 2015 Elsevier Ltd. All rights reserved.

KIRLIANOGRAPHY ESTIMATION OF BIOAVAILABILITY OF SUBSTANCE

Directory of Open Access Journals (Sweden)

M. V. Kuryk

2013-11-01

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

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

Science.gov (United States)

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

2014-10-01

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

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.

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

International Nuclear Information System (INIS)

Zhong Huan; Wang Wenxiong

2009-01-01

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

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

Science.gov (United States)

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

2018-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-03-15

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

Pharmaceutical cocrystals: a novel approach for oral bioavailability enhancement of drugs.

Science.gov (United States)

Chadha, Renu; Saini, Anupam; Arora, Poonam; Bhandari, Swati

2012-01-01

Solid dosage forms are by far the preferred drug delivery systems. However, these often face the problem of poor and erratic bioavailability during the drug development process. Numerous formulation strategies for drug delivery are currently under development, among which the solid forms such as polymorphs, solvates, salts, and cocrystals have been considered to be the most important for improving dissolution rate and bioavailability. Cocrystallization is a fairly new approach in pharmaceutical industry that can improve the solubility and, consequently, the bioactivity of the active pharmaceutical ingredient (API) without compromising its structural integrity. Pharmaceutical cocrystals have found their place in drug delivery, primarily due to their ability to produce alternative, viable solid forms when a more standard approach of salt and polymorph formation fails to deliver the desired objectives. Over the past few years, a number of papers have been published focusing on a broad range of subjects, from traditional crystal engineering to structure-property relationships of cocrystals. The present review, however, illustrates how the cocrystalline forms of APIs have improved their in vitro dissolution rate and in vivo bioavailability, often correlating well with their improved solubility as well.

Food macromolecule based nanodelivery systems for enhancing the bioavailability of polyphenols

Directory of Open Access Journals (Sweden)

Bing Hu

2017-01-01

Full Text Available Diet polyphenols—primarily categorized into flavonoids (e.g., flavonols, flavones, flavan-3-ols, anthocyanidins, flavanones, and isoflavones and nonflavonoids (with major subclasses of stilbenes and phenolic acids—are reported to have health-promoting effects, such as antioxidant, antiinflammatory, anticarcinoma, antimicrobial, antiviral, and cardioprotective properties. However, their applications in functional foods or medicine are limited because of their inefficient systemic delivery and poor oral bioavailability. Epigallocatechin-3-gallate, curcumin, and resveratrol are the well-known representatives of the bioactive diet polyphenols but with poor bioavailability. Food macromolecule based nanoparticles have been fabricated using reassembled proteins, crosslinked polysaccharides, protein–polysaccharide conjugates (complexes, as well as emulsified lipid via safe procedures that could be applied in food. The human gastrointestinal digestion tract is the first place where the food grade macromolecule nanoparticles exert their effects on improving the bioavailability of diet polyphenols, via enhancing their solubility, preventing their degradation in the intestinal environment, elevating the permeation in small intestine, and even increasing their contents in the bloodstream. We contend that the stability and structure behaviors of nanocarriers in the gastrointestinal tract environment and the effects of nanoencapsulation on the metabolism of polyphenols warrant more focused attention in further studies.

Genetic Variations Associated with Vitamin A Status and Vitamin A Bioavailability

Directory of Open Access Journals (Sweden)

Patrick Borel

2017-03-01

Full Text Available Blood concentration of vitamin A (VA, which is present as different molecules, i.e., mainly retinol and provitamin A carotenoids, plus retinyl esters in the postprandial period after a VA-containing meal, is affected by numerous factors: dietary VA intake, VA absorption efficiency, efficiency of provitamin A carotenoid conversion to VA, VA tissue uptake, etc. Most of these factors are in turn modulated by genetic variations in genes encoding proteins involved in VA metabolism. Genome-wide association studies (GWAS and candidate gene association studies have identified single nucleotide polymorphisms (SNPs associated with blood concentrations of retinol and β-carotene, as well as with β-carotene bioavailability. These genetic variations likely explain, at least in part, interindividual variability in VA status and in VA bioavailability. However, much work remains to be done to identify all of the SNPs involved in VA status and bioavailability and to assess the possible involvement of other kinds of genetic variations, e.g., copy number variants and insertions/deletions, in these phenotypes. Yet, the potential usefulness of this area of research is exciting regarding the proposition of more personalized dietary recommendations in VA, particularly in populations at risk of VA deficiency.

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

Science.gov (United States)

Terao, Junji

2017-09-01

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

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.

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

OpenAIRE

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

2014-01-01

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

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

Science.gov (United States)

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

2017-04-01

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

Influence of lifestyle on vitamin bioavailability.

Science.gov (United States)

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

2002-01-01

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

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

International Nuclear Information System (INIS)

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

1995-01-01

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

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

International Nuclear Information System (INIS)

Zhong Huan; Wang Wenxiong

2008-01-01

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

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...

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

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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.

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

Science.gov (United States)

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

2017-11-01

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

Extraction, bioavailability, and bioefficacy of capsaicinoids

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Muwen Lu

2017-01-01

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

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

International Nuclear Information System (INIS)

Nakamaru, Yasuo

2006-01-01

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

Development of Liposome containing sodium deoxycholate to enhance oral bioavailability of itraconazole

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Zhenbao Li

2017-03-01

Full Text Available The aim of this study was to enhance oral bioavailability of itraconazole (ITZ by developing Liposome containing sodium deoxycholate (ITZ-Lip-NaDC. The liposome, consisting of egg yolk lecithin and sodium deoxycholate, was prepared by thin-film dispersion method. Differential Scanning Calorimetry (DSC results indicated an amorphous state in the liposome. The physicochemical characteristics including particle size, morphology, entrapment efficiency, dissolution properties were also investigated. The performance of single-pass intestinal infusion exhibited that the transport order of intestinal segment was jejunum, duodenum, colon and ileum, and that all the segments participated in the absorption of ITZ in intestinal tract. The bioavailability study in rats showed that the AUC0-72 of the liposome was nearly 1.67-fold higher than that of commercial capsules (SPORANOX in terms of oral administration, and the RSD of AUC0-72 of ITZ-Lip-NaDC was also decreased. Our results indicated that ITZ-Lip-NaDC liposome was facilitated to improve dissolution efficiency, augment transmembrane absorption, and then enhance the oral bioavailability of ITZ, successfully.

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

International Nuclear Information System (INIS)

Cui Xinyi; Mayer, Philipp; Gan, Jay

2013-01-01

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

Bioavailability of Trace Elements in Beans and Zinc-Biofortified Wheat in Pigs

DEFF Research Database (Denmark)

Carlson, Dorthe; Nørgaard, Jan Værum; Torun, B

2012-01-01

The objectives of this experiment were to study bioavailability of trace elements in beans and wheat containing different levels of zinc and to study how the water solubility of trace elements was related to the bioavailability in pigs. Three wheat and two bean types were used: wheat of Danish...... origin as a control (CtrlW), two Turkish wheat types low (LZnW) and high (HZnW) in zinc, a common bean (Com), and a faba bean (Faba). Two diets were composed by combining 81 % CtrlW and 19 % Com or Faba beans. Solubility was measured as the trace element concentration in the supernatant of feedstuffs......, and diets incubated in distilled water at pH 4 and 38°C for 3 h. The bioavailability of zinc and copper of the three wheat types and the two bean-containing diets were evaluated in the pigs by collection of urine and feces for 7 days. The solubility of zinc was 34–63 %, copper 18–42 %, and iron 3...

Phenolic Esters of O-Desmethylvenlafaxine with Improved Oral Bioavailability and Brain Uptake

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Yang Zhang

2013-12-01

Full Text Available O-Desmethylvenlafaxine (desvenlafaxine, ODV is a recently approved antidepressant which in some clinical studies failed to meet a satisfactory end-point. The aim of this study was to prepare a series of phenolic esters of ODV and evaluate their potential as ODV prodrugs with improved brain uptake. Fifteen phenolic esters (compounds 1a–o were synthesized and their pharmacokinetic profiles evaluated in rat. The four compounds producing the highest relative bioavailability of ODV in rat (compounds 1c, 1e, 1n, 1o were then studied to evaluate their brain uptake. Of these four compounds, compound 1n (the piperonylic acid ester of ODV demonstrated the highest Cmax of ODV both in the rat hypothalamus and total brain. Finally the pharmacokinetics of 1n were evaluated in beagle dog where the increase in relative bioavailability of ODV was found to be as great as in rat. This high relative bioavailability of ODV coupled with its good brain penetration make 1n the most promising candidate for development as an ODV prodrug.

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

Science.gov (United States)

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

2008-05-01

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

Nanoemulsifying drug delivery system to improve the bioavailability of piroxicam.

Science.gov (United States)

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

2017-05-01

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

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

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Luqing Zheng

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

Recycled water sources influence the bioavailability of copper to earthworms.

Science.gov (United States)

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

2013-10-15

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

Comparing soluble ferric pyrophosphate to common iron salts and chelates as sources of bioavailable iron in a Caco-2 cell culture model.

Science.gov (United States)

Zhu, Le; Glahn, Raymond P; Nelson, Deanna; Miller, Dennis D

2009-06-10

Iron bioavailability from supplements and fortificants varies depending upon the form of the iron and the presence or absence of iron absorption enhancers and inhibitors. Our objectives were to compare the effects of pH and selected enhancers and inhibitors and food matrices on the bioavailability of iron in soluble ferric pyrophosphate (SFP) to other iron fortificants using a Caco-2 cell culture model with or without the combination of in vitro digestion. Ferritin formation was the highest in cells treated with SFP compared to those treated with other iron compounds or chelates. Exposure to pH 2 followed by adjustment to pH 7 markedly decreased FeSO(4) bioavailability but had a smaller effect on bioavailabilities from SFP and sodium iron(III) ethylenediaminetetraacetate (NaFeEDTA), suggesting that chelating agents minimize the effects of pH on iron bioavailability. Adding ascorbic acid (AA) and cysteine to SFP in a 20:1 molar ratio increased ferritin formation by 3- and 2-fold, respectively, whereas adding citrate had no significant effect on the bioavailability of SFP. Adding phytic acid (10:1) and tannic acid (1:1) to iron decreased iron bioavailability from SFP by 91 and 99%, respectively. The addition of zinc had a marked inhibitory effect on iron bioavailability. Calcium and magnesium also inhibited iron bioavailability but to a lesser extent. Incorporating SFP in rice greatly reduced iron bioavailability from SFP, but this effect can be partially reversed with the addition of AA. SFP and FeSO(4) were taken up similarly when added to nonfat dry milk. Our results suggest that dietary factors known to enhance and inhibit iron bioavailability from various iron sources affect iron bioavailability from SFP in similar directions. However, the magnitude of the effects of iron absorption inhibitors on SFP iron appears to be smaller than on iron salts, such as FeSO(4) and FeCl(3). This supports the hypothesis that SFP is a promising iron source for food fortification

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...

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

OpenAIRE

Liu, Ying

2012-01-01

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

Enhanced bioavailability of orally administered flurbiprofen by combined use of hydroxypropyl-cyclodextrin and poly(alkyl-cyanoacrylate) nanoparticles.

Science.gov (United States)

Zhao, Xiaoyun; Li, Wei; Luo, Qiuhua; Zhang, Xiangrong

2014-03-01

Flurbiprofen was formulated into nanoparticle suspension to improve its oral bioavailability. Hydroxypropyl-β-cyclodextrin inclusion-flurbiprofen complex (HP-β-CD-FP) was prepared, then incorporating this complex into poly(alkyl-cyanoacrylate) (PACA) nanoparticles. HP-β-CD-FP-PACA nanoparticle was prepared by the emulsion solvent polymerization method. The zeta potential was -26.8 mV, the mean volume particle diameter was 134 nm, drug encapsulation efficiency was 53.3 ± 3.6 % and concentration was 1.5 mg/mL. The bioavailability of flurbiprofen from optimized nanoparticles was assessed in male Wistar rats at a dose of 15 mg/kg. As compared to the flurbiprofen suspension, 211.6 % relative bioavailability was observed for flurbiprofen nanoparticles. The reduced particle size and increased surface area may contribute to improve oral bioavailability of flurbiprofen.

Polymeric Nanoparticles for Increasing Oral Bioavailability of Curcumin

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Anita Umerska

2018-03-01

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

Is bioavailability altered in generic versus brand anticonvulsants?

Science.gov (United States)

Jankovic, Slobodan M; Ignjatovic Ristic, Dragana

2015-03-01

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

Optimization of Fe2+ supplement in anaerobic digestion accounting for the Fe-bioavailability.

Science.gov (United States)

Cai, Yafan; Zhao, Xiaoling; Zhao, Yubin; Wang, Hongliang; Yuan, Xufeng; Zhu, Wanbin; Cui, Zongjun; Wang, Xiaofen

2018-02-01

Fe is widely used as an additive in anaerobic digestion, but its bioavailability and the mechanism by which it enhances digestion are unclear. In this study, sequential extraction was used to measure Fe bioavailability, while biochemical parameters, kinetics model and Q-PCR (fluorescence quantitative PCR) were used to explore its mechanism of stimulation. The results showed that sequential extraction is a suitable method to assess the anaerobic system bioavailability of Fe, which is low and fluctuates to a limited extent (1.7 to -3.1wt%), indicating that it would be easy for Fe levels to be insufficient. Methane yield increased when the added Fe 2+ was 10-500mg/L. Appropriate amounts of Fe 2+ accelerated the decomposition of rice straw and facilitated methanogen metabolism, thereby improving reactor performance. The modified Gompertz model better fitted the results than the first-order kinetic model. Feasibility analysis showed that addition of Fe 2+ at ≤50mg/L was suitable. Copyright © 2017. Published by Elsevier Ltd.

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

International Nuclear Information System (INIS)

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

2009-01-01

The bioavailability of heavy metals strongly depends on their speciation in the environment. The effect of different chemical speciations of cadmium ions (i.e. adsorbed on different oxide minerals) on its bioavailability to wetland plant Phragmites australis was studied. Goethite, magnetite, gibbsite, alumina, and manganese oxide were chosen as representatives of metal (hydr)oxides commonly present in sediment. The cultivar system with Hoagland solution as nutrition supply, and single metal oxide with adsorbed Cd as contaminant was applied to study Cd accumulation by P. australis. The bioaccumulation degree in root after the 45-day treatment followed the order: Al(OH) 3 > Al 2 O 3 > Fe 3 O 4 > MnO 2 > FeOOH. The concentration of Cd in stem and leaf followed a similar order although it was considerably lower than that in root. Low-molecular-weight organic acids (LMWOAs), acetic acid, malic acid and citric acid were used to evaluate the desorbability of Cd from different oxides, which can be indicative of Cd-oxide bonding strength and Cd bioavailability. Desorption of Cd by acetic acid and malic acid followed the order: Al(OH) 3 > Fe 3 O 4 > Al 2 O 3 > FeOOH > MnO 2 , while by citric acid: Al(OH) 3 ≥ Al 2 O 3 > Fe 3 O 4 > FeOOH > MnO 2 . This was consistent with the Cd accumulation degree in the plant. Cd adsorbed on Al(OH) 3 was the most easily desorbable species and most bioavailable to P. australis among the oxide minerals, whereas MnO 2 adsorbed Cd was least desorbable by LMWOAs hence constituted the least bioavailable Cd species adsorbed on the oxide minerals.

Evaluation of iron bioavailability in a mixture of cereals, seeds, and grains ("Human Ration"

Directory of Open Access Journals (Sweden)

Bárbara Nery Enes

2014-03-01

Full Text Available Iron bioavailability was evaluated in three mixtures of cereals, seeds, and grains ("Human Ration": light, regular, and homemade provided to rats. The animals received an iron depletion diet for 21 days, followed by a repletion diet containing 12 mg·kg-1 of iron for 14 days. The hemoglobin regeneration efficiency and the relative biological value did not differ between the light mixture and control group. The iron bioavailability of the light mixture of cereals, seeds, and grains and the control group were 99.99±27.62 and 80.02±36.63, respectively, while the regular and homemade mixtures of cereals, seeds, and grains showed lower iron bioavailability, 50.12±35.53 and 66.66±15.44, respectively; the iron content of the diet with light cereal mixture light was statistically similar to that of the control (ferrous sulfate 99.99±27.62. The high content of tannin (202.81±19.53 mg·100-1 in the diet with the regular cereal mixture may have contributed to its low iron bioavailability. The higher intake of soluble fiber by the animals fed the light mixture (21.15±0.92 g was moderately correlated (r=0.5712, p=0.0018 with the concentration of propionate in the caecal bulk (65.49±11.08 µmol/g. The short chain fatty acids produced by soluble fiber fermentation, associated with the low-content of tannin may have improved iron solubility and absorption in the light cereal mixture diet. The iron bioavailability in the light mixture of cereals, seeds, and grains was similar to that of ferrous sulfate.

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

Science.gov (United States)

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

2010-08-01

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

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

Science.gov (United States)

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

2018-01-01

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

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

Science.gov (United States)

Avachat, Amelia M; Bhise, Satish B

2011-04-01

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

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

Science.gov (United States)

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

2018-07-27

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

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

DEFF Research Database (Denmark)

Laursen, Torben; Møller, Jens; Ørskov, Hans

1996-01-01

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

Extraction, bioavailability, and bioefficacy of capsaicinoids.

Science.gov (United States)

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

2017-01-01

Capsaicinoids are active constituents responsible for the pungent and spicy flavor in chili peppers. During the past few decades, various extraction methods of capsaicinoids from peppers have been developed with high yields. Through biological studies, pharmacological benefits have been reported such as pain relief, antiinflammation, anticancer, cardio-protection, as well as weight loss. In this paper, the extraction methods and bioavailability of capsaicinoids are reviewed and discussed. In addition, the pharmacological effects and their underlying mechanisms are also studied. Copyright © 2016. Published by Elsevier B.V.

Bioavailability of folate from processed spinach in humans

NARCIS (Netherlands)

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

2000-01-01

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

The influence of bioavailable heavy metals and microbial parameters of soil on the metal accumulation in rice grain.

Science.gov (United States)

Xiao, Ling; Guan, Dongsheng; Peart, M R; Chen, Yujuan; Li, Qiqi; Dai, Jun

2017-10-01

A field-based study was undertaken to analyze the effects of soil bioavailable heavy metals determined by a sequential extraction procedure, and soil microbial parameters on the heavy metal accumulation in rice grain. The results showed that Cd, Cr, Cu, Ni, Pb and Zn concentrations in rice grain decreases by 65.9%, 78.9%, 32.6%, 80.5%, 61.0% and 15.7%, respectively in the sites 3 (far-away), compared with those in sites 1 (close-to). Redundancy analysis (RDA) indicated that soil catalase activity, the MBC/MBN ratio, along with bioavailable Cd, Cr and Ni could explain 68.9% of the total eigenvalue, indicating that these parameters have a great impact on the heavy metal accumulation in rice grain. The soil bioavailable heavy metals have a dominant impact on their accumulation in rice grain, with a variance contribution of 60.1%, while the MBC/MBN has a regulatory effect, with a variance contribution of 4.1%. Stepwise regression analysis showed that the MBC/MBN, urease and catalase activities are the key microbial parameters that affect the heavy metal accumulation in rice by influencing the soil bioavailable heavy metals or the translocation of heavy metals in rice. RDA showed an interactive effect between Cu, Pb and Zn in rice grain and the soil bioavailable Cd, Cr and Ni. The heavy metals in rice grain, with the exception of Pb, could be predicted by their respective soil bioavailable heavy metals. The results suggested that Pb accumulation in rice grain was mainly influenced by the multi-metal interactive effects, and less affected by soil bioavailable Pb. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2018-11-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

NARCIS (Netherlands)

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

2003-01-01

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

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...

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.

Solubility and bioavailability improvement of pazopanib hydrochloride.

Science.gov (United States)

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

2018-06-10

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

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

International Nuclear Information System (INIS)

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

2008-01-01

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

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

Science.gov (United States)

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

2016-06-01

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

Preparation, characterization and relative bioavailability of oral elemene o/w microemulsion

Directory of Open Access Journals (Sweden)

Zhaowu Zeng

2010-08-01

Full Text Available Zhaowu Zeng1, Guanglin Zhou1, Xiaoli Wang2, Eric Zhijian Huang1, Xiaori Zhan1, Jun Liu1, Shuling Wang1, Anming Wang1, Haifeng Li1, Xiaolin Pei1, Tian Xie11Research Center for Biomedicine and Health, Hangzhou Normal University, Hangzhou, Zhejiang, China; 2Yichun University of Jiangxi Province, Yichun, Jiangxi, ChinaAbstract: The objective was to develop an elemene oil/water (o/w microemulsion and evaluate its characteristics and oral relative bioavailability in rats. Elemene was used as the oil phase and drug, polysorbate 80 as a surfactant along with ethanol, propylene glycol, and glycerol as the cosurfactants. The microemulsion was prepared by mixing method, or ultrasonication method in an ultrasonic bath. Its three-dimensional response surface diagram was drawn by Mathcad software. The microemulsion was characterized by visual observation, cross-polarized microscopy, size, zeta potential, acidity, viscosity, and surface tension measurement. The drug content and entrapment efficiency were determined by ultra fast liquid chromatography (UFLC and liquid surface method. Blood was drawn from rats at different time points after oral administration of an elemene microemulsion or a commercial elemene emulsion for measurement of the drug in plasma by UFLC to establish the pharmacokinetic parameters and relative bioavailability. The elemene microemulsion as a clarified and isotropic system containing 1% elemene (w/v, 5% ethanol (v/v, 15% propylene glycol (v/v, 15% glycerol (v/v, and 5% polysorbate 80 (w/v, was characterized as (57.7 ± 2.8 nm in size, 0.485 ± 0.032 in polydispersity index, (3.2 ± 0.4 mv in zeta potential, (5.19 ± 0.08 in pH, 6 mpa•s in viscosity, (31.8 ± 0.3 mN•m-1 in surface tension, (8.273 ± 0.018 mg•mL-1 in content of ß-elemene, and (99.81 ± 0.24% in average entrapment efficiency. The area under the concentration-time curves from 0 h to 24 h (AUC0→24h of the elemene microemulsion and commercial elemene emulsion were

Relative bioavailability of micronized, dispersible ferric pyrophosphate added to an apple juice drink.

Science.gov (United States)

Roe, Mark A; Collings, Rachel; Hoogewerff, Jurian; Fairweather-Tait, Susan J

2009-03-01

Food iron fortification is a sustainable and relatively simple strategy to reduce/prevent iron deficiency but is a challenge for the food industry because of possible adverse organoleptic changes caused by the added iron. A micronized dispersible ferric pyrophosphate, trademarked as SunActive Fe, has recently been developed. SunActive Fe has a small particle size, is water soluble and may be suitable for fortifying liquid products. To determine the relative bioavailability of SunActive Fe and its suitability for addition to pure apple juice. Iron absorption from SunActive Fe added to pure apple juice (Minute Maid) was compared with absorption from ferrous sulphate, a highly bioavailable form of iron, in 15 women with relatively low iron stores. Both forms of iron were enriched with an iron stable isotope and iron absorption from the apple juice drinks was calculated from the isotopic enrichment of red blood cells 14 days after the last test meal. Although mean absorption of iron from SunActive Fe was significantly lower than from ferrous sulphate (5.5% compared with 9.1%), the mean bioavailability of SunActive Fe iron relative to ferrous sulphate was 0.6, indicating that it is a good source of bioavailable iron. Iron Absorption from SunActive Fe was positively correlated (r = 0.97, P = 0.01) with absorption from ferrous sulphate, and negatively correlated with serum ferritin concentration (ferrous sulphate r = -0.81, P apple juice and is a potentially useful fortificant for liquid food products.

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…

Bioaccessibility and bioavailability of methylmercury from seafood commonly consumed in North America: In vitro and epidemiological studies.

Science.gov (United States)

Siedlikowski, Maia; Bradley, Mark; Kubow, Stan; Goodrich, Jaclyn M; Franzblau, Alfred; Basu, Niladri

2016-08-01

Methylmercury (MeHg) is a global contaminant of concern and human exposures are largely realized via seafood consumption. While it is assumed that 95-100% of the ingested MeHg from seafood reaches systemic circulation, recent in vitro studies have yielded results to suggest otherwise. Of the published studies to have characterized the bioaccessibility or bioavailability of MeHg from seafood, only a handful of seafood species have been characterized, there exists tremendous variability in data within and across species, few species of relevance to North America have been studied, and none of the in vitro studies have adapted results to an epidemiology study. The objective of the current study was two-fold: (a) to characterize in vitro MeHg bioaccessibility and bioavailability from ten commonly consumed types of seafood in North America; and (b) to apply the bioaccessibility and bioavailability data from the in vitro study to an existing human MeHg exposure assessment study. Raw seafood samples (cod, crab, halibut, salmon, scallop, shrimp, tilapia, and three tuna types: canned light, canned white, fresh) were purchased in Montreal and their MeHg concentrations generally overlapped with values reported elsewhere. The bioaccessibility of MeHg from these samples ranged from 50.1±19.2 (canned white tuna) to 100% (shrimp and scallop) of the amount measured in the raw undigested sample. The bioavailability of MeHg from these samples ranged from 29.3±10.4 (crab) to 67.4±9.7% (salmon) of the value measured in the raw undigested sample. There were significant correlations between the initial MeHg concentration in seafood with the percent of that Hg that was bioaccessible (r=-0.476) and bioavailable (r=-0.294). When the in vitro data were applied to an existing MeHg exposure assessment study, the estimated amount of MeHg absorbed into systemic circulation decreased by 25% and 42% when considering bioaccessibility and bioavailability, respectively. When the in vitro data

Improved oral bioavailability of poorly water-soluble indirubin by a supersaturatable self-microemulsifying drug delivery system

Directory of Open Access Journals (Sweden)

Chen ZQ

2012-02-01

Full Text Available Zhi-Qiang Chen, Ying Liu, Ji-Hui Zhao, Lan Wang, Nian-Ping FengSchool of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, People's Republic of ChinaBackground: Indirubin, isolated from the leaves of the Chinese herb Isatis tinctoria L, is a protein kinase inhibitor and promising antitumor agent. However, the poor water solubility of indirubin has limited its application. In this study, a supersaturatable self-microemulsifying drug delivery system (S-SMEDDS was developed to improve the oral bioavailability of indirubin.Methods: A prototype S-SMEDDS was designed using solubility studies and phase diagram construction. Precipitation inhibitors were selected from hydrophilic polymers according to their crystallization-inhibiting capacity through in vitro precipitation tests. In vitro release of indirubin from S-SMEDDS was examined to investigate its likely release behavior in vivo. The in vivo bioavailability of indirubin from S-SMEDDS and from SMEDDS was compared in rats.Results: The prototype formulation of S-SMEDDS comprised Maisine™ 35-1:Cremophor® EL:Transcutol® P (15:40:45, w/w/w. Polyvinylpyrrolidone K17, a hydrophilic polymer, was used as a precipitation inhibitor based on its better crystallization-inhibiting capacity compared with polyethylene glycol 4000 and hydroxypropyl methylcellulose. In vitro release analysis showed more rapid drug release from S-SMEDDS than from SMEDDS. In vivo bioavailability analysis in rats indicated that improved oral absorption was achieved and that the relative bioavailability of S-SMEDDS was 129.5% compared with SMEDDS.Conclusion: The novel S-SMEDDS developed in this study increased the dissolution rate and improved the oral bioavailability of indirubin in rats. The results suggest that S-SMEDDS is a superior means of oral delivery of indirubin.Keywords: supersaturatable self-microemulsifying drug delivery system, indirubin, bioavailability, oral drug delivery, hydrophilic polymer

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

Science.gov (United States)

1998-11-01

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

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

DEFF Research Database (Denmark)

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

2017-01-01

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

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

Science.gov (United States)

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

1998-01-01

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

Bioavailability of phosphorus from composts and struvite in acid soils

Directory of Open Access Journals (Sweden)

Carmo Horta

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

Flavanol plasma bioavailability is affected by metabolic syndrome in rats

NARCIS (Netherlands)

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

2017-01-01

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

Bioavailability of morphine, methadone, hydromorphone, and oxymorphone following buccal administration in cats.

Science.gov (United States)

Pypendop, B H; Ilkiw, J E; Shilo-Benjamini, Y

2014-06-01

Buccal administration of buprenorphine is commonly used to treat pain in cats. It has been argued that absorption of buprenorphine through the buccal mucosa is high, in part due to its pKa of 8.24. Morphine, methadone, hydromorphone, and oxymorphone have a pKa between 8 and 9. This study characterized the bioavailability of these drugs following buccal administration to cats. Six healthy adult female spayed cats were used. Buccal pH was measured prior to drug administration. Morphine sulfate, 0.2 mg/kg IV or 0.5 mg/kg buccal; methadone hydrochloride, 0.3 mg/kg IV or 0.75 mg/kg buccal; hydromorphone hydrochloride, 0.1 mg/kg IV or 0.25 mg/kg buccal; or oxymorphone hydrochloride, 0.1 mg/kg IV or 0.25 mg/kg buccal were administered. All cats received all treatments. Arterial blood was sampled immediately prior to drug administration and at various times up to 8 h thereafter. Bioavailability was calculated as the ratio of the area under the time-concentration curve following buccal administration to that following IV administration, each indexed to the administered dose. Mean ± SE (range) bioavailability was 36.6 ± 5.2 (12.7-49.5), 44.2 ± 7.9 (18.7-70.5), 22.4 ± 6.9 (6.4-43.4), and 18.8 ± 2.0 (12.9-23.5)% for buccal administration of morphine, methadone, hydromorphone, and oxymorphone, respectively. Bioavailability of methadone was significantly higher than that of oxymorphone. © 2013 John Wiley & Sons Ltd.

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

Energy Technology Data Exchange (ETDEWEB)

Wang He, E-mail: he.wangworld@yahoo.com.cn [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China); Jia Yongfeng, E-mail: yongfeng.jia@iae.ac.cn [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Wang Shaofeng [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Zhu Huijie; Wu Xing [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China)

2009-08-15

The bioavailability of heavy metals strongly depends on their speciation in the environment. The effect of different chemical speciations of cadmium ions (i.e. adsorbed on different oxide minerals) on its bioavailability to wetland plant Phragmites australis was studied. Goethite, magnetite, gibbsite, alumina, and manganese oxide were chosen as representatives of metal (hydr)oxides commonly present in sediment. The cultivar system with Hoagland solution as nutrition supply, and single metal oxide with adsorbed Cd as contaminant was applied to study Cd accumulation by P. australis. The bioaccumulation degree in root after the 45-day treatment followed the order: Al(OH){sub 3} > Al{sub 2}O{sub 3} > Fe{sub 3}O{sub 4} > MnO{sub 2} > FeOOH. The concentration of Cd in stem and leaf followed a similar order although it was considerably lower than that in root. Low-molecular-weight organic acids (LMWOAs), acetic acid, malic acid and citric acid were used to evaluate the desorbability of Cd from different oxides, which can be indicative of Cd-oxide bonding strength and Cd bioavailability. Desorption of Cd by acetic acid and malic acid followed the order: Al(OH){sub 3} > Fe{sub 3}O{sub 4} > Al{sub 2}O{sub 3} > FeOOH > MnO{sub 2}, while by citric acid: Al(OH){sub 3} {>=} Al{sub 2}O{sub 3} > Fe{sub 3}O{sub 4} > FeOOH > MnO{sub 2}. This was consistent with the Cd accumulation degree in the plant. Cd adsorbed on Al(OH){sub 3} was the most easily desorbable species and most bioavailable to P. australis among the oxide minerals, whereas MnO{sub 2} adsorbed Cd was least desorbable by LMWOAs hence constituted the least bioavailable Cd species adsorbed on the oxide minerals.

Diurnal rhythmicity in biological processes involved in bioavailability of functional food factors.

Science.gov (United States)

Tsurusaki, Takashi; Sakakibara, Hiroyuki; Aoshima, Yoshiki; Yamazaki, Shunsuke; Sakono, Masanobu; Shimoi, Kayoko

2013-05-01

In the past few decades, many types of functional factors have been identified in dietary foods; for example, flavonoids are major groups widely distributed in the plant kingdom. However, the absorption rates of the functional food factors are usually low, and many of these are difficult to be absorbed in the intact forms because of metabolization by biological processes during absorption. To gain adequate beneficial effects, it is therefore mandatory to know whether functional food factors are absorbed in sufficient quantity, and then reach target organs while maintaining beneficial effects. These are the reasons why the bioavailability of functional food factors has been well investigated using rodent models. Recently, many of the biological processes have been reported to follow diurnal rhythms recurring every 24 h. Therefore, absorption and metabolism of functional food factors influenced by the biological processes may vary with time of day. Consequently, the evaluation of the bioavailability of functional food factors using rodent models should take into consideration the timing of consumption. In this review, we provide a perspective overview of the diurnal rhythm of biological processes involved in the bioavailability of functional food factors, particularly flavonoids.

Digoxin: use pattern in Estonia and bioavailability of the local market leader.

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Pähkla, R; Irs, A; Oselin, K; Rootslane, L

1999-10-01

In comparison with neighbouring Scandinavian countries, the use of digoxin in Estonia is high. The present study was carried out to determine the use pattern of digoxin in Estonia and bioavailability of the local market leader preparation in comparison with Lanoxin. Drug use data were evaluated from the annual reports of wholesale companies. For the bioequivalence study, a single-blind cross-over randomised two-way single-dose comparative bioavailability study was performed using 14 healthy volunteers. Digoxin concentrations in serum samples and urine were measured by chemiluminescent competitive immunoassay. The use of digoxin in Estonia has increased by 35% during the period 1994-97. The steady market leader was the local generic drug. No statistically significant differences were found in any pharmacokinetic parameter between the generic preparation and Lanoxin. All parameters showed considerable variability. The total amount of drug excreted was the parameter with lowest inter- individual variation. The present study indicates that the generic digoxin preparation studied is bioequivalent to Lanoxin. The increasing use of digoxin in Estonia is not caused by low bioavailability of the local market leader but by therapeutic traditions.

Modelling chelate-Induced phytoextraction: functional models predicting bioavailability of metals in soil, metal uptake and shoot biomass

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Pasqualina Sacco

2006-06-01

Full Text Available Chelate-induced phytoextraction of heavy metals from contaminated soils requires special care to determine, a priori, the best method of chelate application, in terms of both dose and timing. In fact, the chelate dose must assure the bioavailability of the metal to the plant without increasing leaching risk and giving toxic effects. Three mathematical models are here proposed for usefully interpreting the processes taking place: a increased soil bioavailability of metals by chelants; b metal uptake by plants; c variation in plant biomass. The models are implemented and validated using data from pot and lysimeter trials. Both the chelate dose and the time elapsed since its application affected metal bioavailability and plant response. Contrariwise, the distribution strategy (single vs. split application seems to produce significant differences both in plant growth and metal uptake, but not in soil metal bioavailability. The proposed models may help to understand and predict the chelate dose – effect relationship with less experimental work.

Influence of particle characteristics and organic matter content on the bioavailability and bioaccumulation of pyrene by clams

International Nuclear Information System (INIS)

Verrengia Guerrero, N.R.; Taylor, M.G.; Wider, E.A.; Simkiss, K.

2003-01-01

An experimental model with artificial particles and humic acids describes bioavailability of sediment-bound pyrene to clams. - Hydrophobic chemicals are known to associate with sediment particles including those from both suspended particulate matter and bottom deposits. The complex and variable composition of natural particles makes it very difficult therefore, to predict the bioavailability of sediment-bound contaminants. To overcome these problems we have previously devised a test system using artificial particles, with or without humic acids, for use as an experimental model of natural sediments. In the present work we have applied this experimental technique to investigate the bioavailability and bioaccumulation of pyrene by the freshwater fingernail clam Sphaerium corneum. The uptake and accumulation of pyrene in clams exposed to the chemical in the presence of a sample of natural sediment was also investigated. According to the results obtained, particle surface properties and organic matter content are the key factors for assessing the bioavailability and bioaccumulation of pyrene by clams

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.

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

DEFF Research Database (Denmark)

Mu, Huiling

2008-01-01

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

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

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

2012-02-01

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

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

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Rajib Podder

2018-03-01

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

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

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

2018-03-15

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

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

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

2014-05-01

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

Higher bioavailability of iron from whole wheat bread compared with iron-fortified white breads in caco-2 cell model: an experimental study.

Science.gov (United States)

Nikooyeh, Bahareh; Neyestani, Tirang R

2017-06-01

Bread, as the staple food of Iranians, with average per capita consumption of 300 g d -1 , could potentially be a good vehicle for many fortificants, including iron. In this study, iron bioavailability from flat breads (three fortified and one whole wheat unfortified) was investigated using in vitro simulation of gastrointestinal digestion and absorption in a caco-2 cell model. Despite having a lower ferritin/protein ratio in comparison with fortified breads, whole wheat bread showed higher iron bioavailability than the other three types of bread. Assuming iron bioavailability from the ferrous sulfate supplement used as standard was about 10%, the estimated bioavailability of iron from the test breads was calculated as 5.0-8.0%. Whole wheat bread (∼8%), as compared with the fortified breads (∼5-6.5%), had higher iron bioavailability. Iron from unfortified whole wheat bread is more bioavailable than from three types of iron-fortified breads. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Improved oral bioavailability of poorly water-soluble indirubin by a supersaturatable self-microemulsifying drug delivery system.

Science.gov (United States)

Chen, Zhi-Qiang; Liu, Ying; Zhao, Ji-Hui; Wang, Lan; Feng, Nian-Ping

2012-01-01

Indirubin, isolated from the leaves of the Chinese herb Isatis tinctoria L, is a protein kinase inhibitor and promising antitumor agent. However, the poor water solubility of indirubin has limited its application. In this study, a supersaturatable self-microemulsifying drug delivery system (S-SMEDDS) was developed to improve the oral bioavailability of indirubin. A prototype S-SMEDDS was designed using solubility studies and phase diagram construction. Precipitation inhibitors were selected from hydrophilic polymers according to their crystallization-inhibiting capacity through in vitro precipitation tests. In vitro release of indirubin from S-SMEDDS was examined to investigate its likely release behavior in vivo. The in vivo bioavailability of indirubin from S-SMEDDS and from SMEDDS was compared in rats. The prototype formulation of S-SMEDDS comprised Maisine™ 35-1:Cremophor(®) EL:Transcutol(®) P (15:40:45, w/w/w). Polyvinylpyrrolidone K17, a hydrophilic polymer, was used as a precipitation inhibitor based on its better crystallization-inhibiting capacity compared with polyethylene glycol 4000 and hydroxypropyl methylcellulose. In vitro release analysis showed more rapid drug release from S-SMEDDS than from SMEDDS. In vivo bioavailability analysis in rats indicated that improved oral absorption was achieved and that the relative bioavailability of S-SMEDDS was 129.5% compared with SMEDDS. The novel S-SMEDDS developed in this study increased the dissolution rate and improved the oral bioavailability of indirubin in rats. The results suggest that S-SMEDDS is a superior means of oral delivery of indirubin.

Effects of biochar and Arbuscular mycorrhizae on bioavailability of potentially toxic elements in an aged contaminated soil

International Nuclear Information System (INIS)

Qiao, Yuhui; Crowley, David; Wang, Kun; Zhang, Huiqi; Li, Huafen

2015-01-01

Biochar pyrolyzed from corn stalks at 300 °C/500 °C and arbuscular mycorrhizae (AMF) were examined independently and in combination as possible treatments for soil remediation contaminated with Cd, Cr, Ni, Cu, Pb, Zn after 35 years following land application of sewage sludge in the 1970s. The results showed that biochar significantly decreased the heavy metal concentrations and their bioavailability for plants, and both biochars had similar such effects. AMF inoculation of corn plants had little effect on heavy metal bioavailability in either control or biochar amended soil, and no interaction between biochar and AMF was observed. Changes in DTPA extractable metals following biochar addition to soil were correlated with metal uptake by plants, whereas pore water metal concentrations were not predictive indicators. This research demonstrates positive benefits from biochar application for contaminated soil remediation, but remain ambiguous with regard to the benefits of simultaneous AMF inoculation on reduction of heavy metal bioavailability. - Highlights: • Biochar pyrolyzed from corn stalks at 300 °C/500 °C can increase the biomass of corn growing in a heavily contaminated soil. • Biochar could significantly decrease bioavailability of heavy metals (Cd, Cr, Ni, Cu, Zn) for plants. • Effects were not augmented by the addition of AMF although the production of glomalin is promoted by biochars. • AMF had not reduced bioavailability of PTEs, no significant interaction between biochar and AMF inoculation was observed. - Biochar could significantly decrease bioavailability of heavy metals (Cd, Cr, Ni, Cu, Zn) for plants, but AMF had little such effects, biochar and AMF interaction is not valid.

Influence of the Encapsulation Efficiency and Size of Liposome on the Oral Bioavailability of Griseofulvin-Loaded Liposomes

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Sandy Gim Ming Ong

2016-08-01

Full Text Available The objective of the present study was to investigate the influence of the encapsulation efficiency and size of liposome on the oral bioavailability of griseofulvin-loaded liposomes. Griseofulvin-loaded liposomes with desired characteristics were prepared from pro-liposome using various techniques. To study the effect of encapsulation efficiency, three preparations of griseofulvin, namely, griseofulvin aqueous suspension and two griseofulvin-loaded liposomes with different amounts of griseofulvin encapsulated [i.e., F1 (32% and F2(98%], were administered to rats. On the other hand, to study the effect of liposome size, the rats were given three different griseofulvin-loaded liposomes of various sizes, generated via different mechanical dispersion techniques [i.e., FTS (142 nm, MS (357 nm and NS (813 nm], but with essentially similar encapsulation efficiencies (about 93%. Results indicated that the extent of bioavailability of griseofulvin was improved 1.7–2.0 times when given in the form of liposomes (F1 compared to griseofulvin suspension. Besides that, there was an approximately two-fold enhancement of the extent of bioavailability following administration of griseofulvin-loaded liposomes with higher encapsulation efficiency (F2, compared to those of F1. Also, the results showed that the extent of bioavailability of liposomal formulations with smaller sizes were higher by approximately three times compared to liposomal formulation of a larger size. Nevertheless, a further size reduction of griseofulvin-loaded liposome (≤400 nm did not promote the uptake or bioavailability of griseofulvin. In conclusion, high drug encapsulation efficiency and small liposome size could enhance the oral bioavailability of griseofulvin-loaded liposomes and therefore these two parameters deserve careful consideration during formulation.

Dissolution and bioavailability enhancement of alpha-asarone by solid dispersions via oral administration.

Science.gov (United States)

Deng, Li; Wang, Yu; Gong, Tao; Sun, Xun; Zhang, Zhi-Rong

2017-11-01

Alpha (α)-asarone (1-propenyl-2,4,5-methoxybenzol) (ARE) has been extensively used to treat chronic obstructive pulmonary diseases (COPD), bronchial asthma, pneumonia, and epilepsy. Due to its poor solubility and bioavailability, ARE was clinically administered via intravenous injection. However, severe allergies were often reported due to the presence of solublizers in the injection formulation. In our study, we sought to explore the biopharmaceutical classification of ARE, elucidate the mechanisms behind ARE absorption, and to develop a viable formulation to improve the oral bioavailability of ARE. ARE was not a P-glycoprotein substrate, which was absorbed in the passive mode without site specificity in the gastrointestinal tract. Solid dispersions prepared using hydrophilic matrix materials such as Pluronic F68, and polyethylene glycol (PEG) of varying molecular weights (PEG4K, PEG10K, and PEG20K) were proven to significantly improve the dissolution of ARE in vitro and the oral bioavailability of ARE in rats, which represent a promising strategy for the oral administration of ARE and other BCS II compounds.

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

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Li C

2012-12-01

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

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

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

2017-11-01

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

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

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

2017-11-01

Metal oxide nanoparticles (MeO-NPs) are among the most consumed NPs and also have wide applications in various areas which increased their release into the environmental system. Aquatic (water and sediments) and terrestrial compartments are predicted to be the destination of the released MeO-NPs. In these compartments, the particles are subjected to various dynamic processes such as physical, chemical and biological processes, and undergo transformations which drive them away from their pristine state. These transformation pathways can have strong implications for the fate, transport, persistence, bioavailability and toxic-effects of the NPs. In this critical review, we provide the state-of-the-knowledge on the transformation processes and bioavailability of MeO-NPs in the environment, which is the topic of interest to researchers. We also recommend future research directions in the area which will support future risk assessments by enhancing our knowledge of the transformation and bioavailability of MeO-NPs. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

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

2017-09-15

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

Formulation of itraconazole nanococrystals and evaluation of their bioavailability in dogs.

Science.gov (United States)

De Smet, Lieselotte; Saerens, Lien; De Beer, Thomas; Carleer, Robert; Adriaensens, Peter; Van Bocxlaer, Jan; Vervaet, Chris; Remon, Jean Paul

2014-05-01

The aim of the study is to increase the bioavailability of itraconazole (ITRA) using nanosized cocrystals prepared via wet milling of ITRA in combination with dicarboxylic acids. Wet milling was used in order to create a nanosuspension of ITRA in combination with dicarboxylic acids. After spray-drying and bead layering, solid state was characterized by MDSC, XRD, Raman and FT-IR. The release profiles and bioavailability of the nanococrystalline suspension, the spray-dried and bead layered formulation were evaluated. A monodisperse nanosuspension (549±51nm) of ITRA was developed using adipic acid and Tween®80. Solid state characterization indicated the formation of nanococrystals by hydrogen bounds between the triazole group of ITRA and the carboxyl group of adipic acid. A bioavailability study was performed in dogs. The faster drug release from the nanocrystal-based formulation was reflected in the in vivo results since Tmax of the formulations was obtained 3h after administration, while Tmax of the reference formulation was observed only 6h after administration. This fast release of ITRA was obtained by a dual concept: manufacturing of nanosized cocrystals of ITRA and adipic acid via wet milling. Formation of stable nanosized cocrystals via this approach seems a good alternative for amorphous systems to increase the solubility and obtain a fast drug release of BCS class II drugs. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of activated carbon on microbial bioavailability of phenanthrene in soils

Energy Technology Data Exchange (ETDEWEB)

Yang, Y.; Hunter, W.; Tao, S.; Crowley, D.; Gan, J. [University of California Riverside, Riverside, CA (United States). Dept. of Environmental Science

2009-11-15

Bioavailability is a governing factor that controls the rate of biological degradation of hydrophobic organic contaminants in soil. Among the solid phases that can adsorb hydrophobic organic contaminants in soil, black carbon (BC) exerts a particularly significant effect on phase distribution. However, knowledge on the effect of BC on the microbial availability of polycyclic aromatic hydrocarbons in soil is still limited. In the present study, the effect of a coal-derived activated carbon on the bioavailability of phenanthrene (PHE) during its degradation by Mycobacterium vanbaalenii PYR-1 was measured in three soils. The freely dissolved concentration of PHE was concurrently determined in soil solutions using disposable polydimethylsiloxane fibers. The results showed that PHE mineralization was significantly inhibited after addition of activated carbon in all test soils. After 216 h, only 5.20, 5.83, and 6.85% of PHE was degraded in the 0.5% BC-amended soils initially containing organic carbon at 0.23, 2.1, and 7.1%, respectively. Significant correlation was found between PHE degradability and freely dissolved concentration, suggesting that BC affected PHE bioavailability by decreasing chemical activity. The effect of activated carbon in the amended soils was attributed to its enhancement of soil surface areas and pore volumes. Results from the present study clearly highlighted the importance of BC for influencing the microbial availability of polycyclic aromatic hydrocarbons in soils.

Coamorphous Loratadine-Citric Acid System with Enhanced Physical Stability and Bioavailability.

Science.gov (United States)

Wang, Jin; Chang, Ruimiao; Zhao, Yanan; Zhang, Jiye; Zhang, Ting; Fu, Qiang; Chang, Chun; Zeng, Aiguo

2017-10-01

Coamorphous systems using citric acid as a small molecular excipient were studied for improving physical stability and bioavailability of loratadine, a BCS class II drug with low water solubility and high permeability. Coamorphous loratadine-citric acid systems were prepared by solvent evaporation technique and characterized by differential scanning calorimetry, X-ray powder diffraction, and Fourier transform infrared spectroscopy. Solid-state analysis proofed that coamorphous loratadine-citric acid system (1:1) was amorphous and homogeneous, had a higher T g over amorphous loratadine, and the intermolecular hydrogen bond interactions between loratadine and citric acid exist. The solubility and dissolution of coamorphous loratadine-citric acid system (1:1) were found to be significantly greater than those of crystalline and amorphous form. The pharmacokinetic study in rats proved that coamorphous loratadine-citric acid system (1:1) could significantly improve absorption and bioavailability of loratadine. Coamorphous loratadine-citric acid system (1:1) showed excellently physical stability over a period of 3 months at 25°C under 0% RH and 25°C under 60% RH conditions. The improved stability of coamorphous loratadine-citric acid system (1:1) could be related to an elevated T g over amorphous form and the intermolecular hydrogen bond interactions between loratadine and citric acid. These studies demonstrate that the developed coamorphous loratadine-citric acid system might be a promising oral formulation for improving solubility and bioavailability of loratadine.

Cellular retinoic acid bioavailability in various pathologies and its therapeutic implication.

Science.gov (United States)

Osanai, Makoto

2017-06-01

Retinoic acid (RA), an active metabolite of vitamin A, is a critical signaling molecule in various cell types. We found that RA depletion caused by expression of the RA-metabolizing enzyme CYP26A1 promotes carcinogenesis, implicating CYP26A1 as a candidate oncogene. Several studies of CYP26s have suggested that the biological effect of RA on target cells is primarily determined by "cellular RA bioavailability", which is defined as the RA level in an individual cell, rather than by the serum concentration of RA. Consistently, stellate cells store approximately 80% of vitamin A in the body, and the state of cellular RA bioavailability regulates their function. Based on the similarities between stellate cells and astrocytes, we demonstrated that retinal astrocytes regulate tight junction-based endothelial integrity in a paracrine manner. Since diabetic retinopathy is characterized by increased vascular permeability in its early pathogenesis, RA normalized retinal astrocytes that are compromised in diabetes, resulting in suppression of vascular leakiness. RA also attenuated the loss of the epithelial barrier in murine experimental colitis. The concept of "cellular RA bioavailability" in various diseases will be directed at understanding various pathologies caused by RA insufficiency, implying the potential feasibility of a therapeutic strategy targeting the stellate cell system. © 2017 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.

Milk does not affect the bioavailability of cocoa powder flavonoid in healthy human.

Science.gov (United States)

Roura, Elena; Andrés-Lacueva, Cristina; Estruch, Ramon; Mata-Bilbao, M Lourdes; Izquierdo-Pulido, Maria; Waterhouse, Andrew L; Lamuela-Raventós, Rosa M

2007-01-01

The beneficial effects of cocoa polyphenols depend on the amount consumed, their bioavailability and the biological activities of the formed conjugates. The food matrix is one the factors than can affect their bioavailability, but previous studies have concluded rather contradictory results about the effect of milk on the bioavailability of polyphenols. The objective was to evaluate the possible interaction of milk on the absorption of (-)-epicatechin ((-)-Ec) from cocoa powder in healthy humans. 21 volunteers received three interventions in a randomized crossover design with a 1-week interval (250 ml of whole milk (M-c) (control), 40 g of cocoa powder dissolved in 250 ml of whole milk (CC-M), and 40 g of cocoa powder dissolved with 250 ml of water (CC-W)). Quantification of (-)-Ec in plasma was determined by LC-MS/MS analysis prior to a solid-phase extraction procedure. 2 h after the intake of the two cocoa beverages, (-)-Ec-glucuronide was the only (-)-Ec metabolite detected, showing a mean (SD) plasma concentration of 330.44 nmol/l (156.1) and 273.7 nmol/l (138.42) for CC-W and CC-M, respectively (p = 0.076). Cocoa powder dissolved in milk as one of the most common ways of cocoa powder consumption seems to have a negative effect on the absorption of polyphenols; however, statistical analyses have shown that milk does not impair the bioavailability of polyphenols and thus their potential beneficial effect in chronic and degenerative disease prevention. (c) 2007 S. Karger AG, Basel

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

Science.gov (United States)

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

2017-03-01

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

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

NARCIS (Netherlands)

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

2012-01-01

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

Copper bioavailability and extractability as related to chemical properties of contaminated soils from a vine-growing area

International Nuclear Information System (INIS)

Chaignon, V.; Sanchez-Neira, I.; Herrmann, P.; Jaillard, B.; Hinsinger, P.

2003-01-01

Root Cu concentration is a good indicator of soil Cu bioavailability. - Vineyard soils have been contaminated by Cu as a consequence of the long-term use of Cu salts as fungicides against mildew. This work aimed at identifying which soil parameters were the best related to Cu bioavailability, as assessed by measuring the concentrations of Cu in shoots and roots of tomato cropped (in lab conditions) over a range of 29 (24 calcareous and five acidic) Cu-contaminated topsoils from a vine-growing area (22-398 mg Cu kg -1 ). Copper concentrations in tomato shoots remained in the adequate range and were independent of soil properties and soil Cu content. Conversely, strong, positive correlations were found between root Cu concentration, total soil Cu, EDTA- or K-pyrophosphate-extractable Cu and organic C contents in the 24 calcareous soils, suggesting a prominent role of organic matter in the retention and bioavailability of Cu. Such relations were not observed when including the five acidic soils in the investigated population, suggesting a major pH effect. Root Cu concentration appeared as a much more sensitive indicator of soil Cu bioavailability than shoot Cu concentration. Simple extractions routinely used in soil testing procedures (total and EDTA-extractable Cu) were adequate indicators of Cu bioavailability for the investigated calcareous soils, but not when different soil types were considered (e.g. acidic versus calcareous soils)

Prediction of the bioavailability of potentially toxic elements in freshwaters. Comparison between speciation models and passive samplers.

Science.gov (United States)

Sierra, Jordi; Roig, Neus; Giménez Papiol, Gemma; Pérez-Gallego, Elena; Schuhmacher, Marta

2017-12-15

The aim of this work is to predict the bioavailability of the Potentially Toxic Elements (PTEs) Cd, Pb, Hg, Ni, Cu, Zn, As, Cr and Se in 6 sites within the Ebro River basin. In situ Diffusive gradient in thin-films (DGTs) and classical sampling have been used and compared. The potentially bioavailable fractions of each PTE was estimated by modelling their chemical speciation using three programs (WHAM 7.0, Visual MINTEQ 3.1 and Bio-met), following the suggestions published in recent European regulations. Results of the equilibrium-based models WHAM 7.0 and Visual MINTEQ 3.1 indicate that As, Cd, Ni, Se and Zn, predominate as free metals ions or forming inorganic soluble complexes. Copper, Pb and Hg bioavailability is conditioned by their affinity to dissolved humic substances. According to Visual MINTEQ 3.1, Cr is subjected to redox reactions, being Cr (VI) present (at low concentrations) in the studied rivers. According to Bio-met model, the bioavailability of Cu and Zn is highly influenced by soluble organic matter and water hardness, respectively. For most PTEs, the bioavailability estimated by deploying DGTs in river waters tends to be slightly lower than the estimation obtained with speciation models, since in real conditions more environmental factors take place comparing to the finite number of parameters considered in models. Copyright © 2017 Elsevier B.V. All rights reserved.

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

International Nuclear Information System (INIS)

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

2006-01-01

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

Rapid persulfate oxidation predicts PAH bioavailability in soils and sediments

NARCIS (Netherlands)

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

2000-01-01

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

Dynamic speciation analysis and bioavailability of metals in aquatic systems

NARCIS (Netherlands)

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

2005-01-01

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

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

Use of chemical methods to assess Cd and Pb bioavailability to the snail Cantareus aspersus: A first attempt taking into account soil characteristics

International Nuclear Information System (INIS)

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

2011-01-01

Highlights: → New methodology to identify chemical method able to assess metal bioavailability to snails. → Bioavailability of cadmium and lead to snails was determined by assessing accumulation kinetics. → Toxicokinetics were used to as a measure of bioavailability and related with chemical measures of metal availability. → Bioavailability of cadmium and lead was affected by different pH and organic matter content but not by clay content. → Concentrations of CaCl 2 extract and total dissolved metal estimate were not able to predict bioavailability to the snails. - Abstract: Bioavailability is a key parameter in conditioning contaminant transfer to biota. However, in risk assessment of terrestrial contamination, insufficient attention is being paid to the influence of soil type on trace metal bioavailability. This paper addresses the influence of soil properties on the chemical availability of cadmium (Cd) and lead (Pb) (CaCl 2 extraction and ionic activity) and bioavailability (accumulation kinetics) to the land snail Cantareus aspersus. Snails were exposed to nine contaminated soils differing by a single characteristic (pH or organic matter content or clay content) for 28 days. Toxicokinetic models were applied to determine metal uptake and excretion rates in snails and multivariate regression was used to relate uptake parameters to soil properties. The results showed that alkalinisation of soil and an increase of the organic matter content decreased Pb and Cd bioavailability to snails whereas kaolin clay had no significant influence. The CaCl 2 -extractable concentrations tended to overestimate the effects of pH when used to explain metal uptake rate. We conclude that factors other than those controlling the extractable fraction affect metal bioavailability to snails, confirming the requirement of biota measurements in risk assessment procedures.

Use of chemical methods to assess Cd and Pb bioavailability to the snail Cantareus aspersus: A first attempt taking into account soil characteristics

Energy Technology Data Exchange (ETDEWEB)

Pauget, B. [Department Chrono-Environment, UMR UFC/CNRS 6249 USC INRA, University of Franche-Comte, Place Leclerc, F-25030 Besancon Cedex (France); Gimbert, F., E-mail: frederic.gimbert@univ-fcomte.fr [Department Chrono-Environment, UMR UFC/CNRS 6249 USC INRA, University of Franche-Comte, Place Leclerc, F-25030 Besancon Cedex (France); Coeurdassier, M.; Scheifler, R.; Vaufleury, A. de [Department Chrono-Environment, UMR UFC/CNRS 6249 USC INRA, University of Franche-Comte, Place Leclerc, F-25030 Besancon Cedex (France)

2011-09-15

Highlights: {yields} New methodology to identify chemical method able to assess metal bioavailability to snails. {yields} Bioavailability of cadmium and lead to snails was determined by assessing accumulation kinetics. {yields} Toxicokinetics were used to as a measure of bioavailability and related with chemical measures of metal availability. {yields} Bioavailability of cadmium and lead was affected by different pH and organic matter content but not by clay content. {yields} Concentrations of CaCl{sub 2} extract and total dissolved metal estimate were not able to predict bioavailability to the snails. - Abstract: Bioavailability is a key parameter in conditioning contaminant transfer to biota. However, in risk assessment of terrestrial contamination, insufficient attention is being paid to the influence of soil type on trace metal bioavailability. This paper addresses the influence of soil properties on the chemical availability of cadmium (Cd) and lead (Pb) (CaCl{sub 2} extraction and ionic activity) and bioavailability (accumulation kinetics) to the land snail Cantareus aspersus. Snails were exposed to nine contaminated soils differing by a single characteristic (pH or organic matter content or clay content) for 28 days. Toxicokinetic models were applied to determine metal uptake and excretion rates in snails and multivariate regression was used to relate uptake parameters to soil properties. The results showed that alkalinisation of soil and an increase of the organic matter content decreased Pb and Cd bioavailability to snails whereas kaolin clay had no significant influence. The CaCl{sub 2}-extractable concentrations tended to overestimate the effects of pH when used to explain metal uptake rate. We conclude that factors other than those controlling the extractable fraction affect metal bioavailability to snails, confirming the requirement of biota measurements in risk assessment procedures.

Preparation, characterization and relative bioavailability of oral elemene o/w microemulsion

Science.gov (United States)

Zeng, Zhaowu; Zhou, Guanglin; Wang, Xiaoli; Huang, Eric Zhijian; Zhan, Xiaori; Liu, Jun; Wang, Shuling; Wang, Anming; Li, Haifeng; Pei, Xiaolin; Xie, Tian

2010-01-01

The objective was to develop an elemene oil/water (o/w) microemulsion and evaluate its characteristics and oral relative bioavailability in rats. Elemene was used as the oil phase and drug, polysorbate 80 as a surfactant along with ethanol, propylene glycol, and glycerol as the cosurfactants. The microemulsion was prepared by mixing method, or ultrasonication method in an ultrasonic bath. Its three-dimensional response surface diagram was drawn by Mathcad software. The microemulsion was characterized by visual observation, cross-polarized microscopy, size, zeta potential, acidity, viscosity, and surface tension measurement. The drug content and entrapment efficiency were determined by ultra fast liquid chromatography (UFLC) and liquid surface method. Blood was drawn from rats at different time points after oral administration of an elemene microemulsion or a commercial elemene emulsion for measurement of the drug in plasma by UFLC to establish the pharmacokinetic parameters and relative bioavailability. The elemene microemulsion as a clarified and isotropic system containing 1% elemene (w/v), 5% ethanol (v/v), 15% propylene glycol (v/v), 15% glycerol (v/v), and 5% polysorbate 80 (w/v), was characterized as (57.7 ± 2.8) nm in size, 0.485 ± 0.032 in polydispersity index, (3.2 ± 0.4) mv in zeta potential, (5.19 ± 0.08) in pH, 6 mpa·s in viscosity, (31.8 ± 0.3) mN·m−1 in surface tension, (8.273 ± 0.018) mg·mL−1 in content of β-elemene, and (99.81 ± 0.24)% in average entrapment efficiency. The area under the concentration-time curves from 0 h to 24 h (AUC0→24h) of the elemene microemulsion and commercial elemene emulsion were integrated to be 3.092 mg·h·L−1 and 1.896 mg·h·L−1 respectively, yielding a relative bioavailability of 163.1%. The present study demonstrates the elemene microemulsion as a new formulation with ease of preparation, high entrapment efficiency, excellent clarity, good stability, and improved bioavailability. PMID:20856831

Preparation, characterization and relative bioavailability of oral elemene o/w microemulsion.

Science.gov (United States)

Zeng, Zhaowu; Zhou, Guanglin; Wang, Xiaoli; Huang, Eric Zhijian; Zhan, Xiaori; Liu, Jun; Wang, Shuling; Wang, Anming; Li, Haifeng; Pei, Xiaolin; Xie, Tian

2010-09-07

The objective was to develop an elemene oil/water (o/w) microemulsion and evaluate its characteristics and oral relative bioavailability in rats. Elemene was used as the oil phase and drug, polysorbate 80 as a surfactant along with ethanol, propylene glycol, and glycerol as the cosurfactants. The microemulsion was prepared by mixing method, or ultrasonication method in an ultrasonic bath. Its three-dimensional response surface diagram was drawn by Mathcad software. The microemulsion was characterized by visual observation, cross-polarized microscopy, size, zeta potential, acidity, viscosity, and surface tension measurement. The drug content and entrapment efficiency were determined by ultra fast liquid chromatography (UFLC) and liquid surface method. Blood was drawn from rats at different time points after oral administration of an elemene microemulsion or a commercial elemene emulsion for measurement of the drug in plasma by UFLC to establish the pharmacokinetic parameters and relative bioavailability. The elemene microemulsion as a clarified and isotropic system containing 1% elemene (w/v), 5% ethanol (v/v), 15% propylene glycol (v/v), 15% glycerol (v/v), and 5% polysorbate 80 (w/v), was characterized as (57.7 ± 2.8) nm in size, 0.485 ± 0.032 in polydispersity index, (3.2 ± 0.4) mv in zeta potential, (5.19 ± 0.08) in pH, 6 mpa·s in viscosity, (31.8 ± 0.3) mN·m(-1) in surface tension, (8.273 ± 0.018) mg·mL(-1) in content of β-elemene, and (99.81 ± 0.24)% in average entrapment efficiency. The area under the concentration-time curves from 0 h to 24 h (AUC(0→24h)) of the elemene microemulsion and commercial elemene emulsion were integrated to be 3.092 mg·h·L(-1) and 1.896 mg·h·L(-1) respectively, yielding a relative bioavailability of 163.1%. The present study demonstrates the elemene microemulsion as a new formulation with ease of preparation, high entrapment efficiency, excellent clarity, good stability, and improved bioavailability.

Influences of humic acid on the bioavailability of phenanthrene and alkyl phenanthrenes to early life stages of marine medaka (Oryzias melastigma)

International Nuclear Information System (INIS)

Liu, Yangzhi; Yang, Chenghu; Cheng, Pakkin; He, Xiaojing; Zhu, Yaxian; Zhang, Yong

2016-01-01

The influences of humic acid (HA) on the environmental behavior and bioavailability of parent polycyclic aromatic hydrocarbons (PAHs) and alkyl PAHs were investigated and compared using the early life stages of marine medaka (Oryzias melastigma, O. melastigma). It was demonstrated that the binding affinity of parent phenanthrene (PHE) with HA was smaller than that of 3-methyl phenanthrene (3-MP) and 9-ethyl phenanthrene (9-EP). Furthermore, the bioaccumulation of the three PAHs and the levels of lipid peroxidation (LPO) were calculated to study the changes in bioavailability of PAHs in presence of HA. The results indicated that the addition of HA significantly decreased the bioaccumulation and toxicity of PAHs by decreasing free PAHs concentrations. The bioavailable fractions of HA-bound PAHs in bioaccumulation (α) and toxicity (β) were evaluated, indicating that the HA-bound 3-MP and 9-EP show higher bioavailability in bioaccumulation and lower bioavailability in toxicity relative to those of PHE. The β/α values were less than 1 for all PAH treatment groups containing HA, suggesting that the fraction of HA-bound PAHs contributing to bioaccumulation was higher than that of HA-bound PAHs inducing toxic effect. In addition, we proposed that the free PAHs generated by desorption from HA in the cell were toxic by showing that the β/α ratio values are correlated with the log K_O_W values (p = 0.007 and R"2 = 0.8355). Thus, oil spill risk assessments should consider both alkyl PAHs and the factors that influence the bioavailability and toxicity of PAHs in the natural aquatic environments. - Highlights: • Effects of HA on bioavailability of parent and alkyl PAHs were firstly compared. • Changes in the bioavailability due to HA depended on the alkylation of PAHs. • The bioavailable fractions of the HA-bound parent and alkyl PAHs were calculated. • The toxicity of HA-bound PAHs was related to the physicochemical properties of PAHs. - This study is the

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

Science.gov (United States)

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

2007-02-01

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

Assessment of the bioavailability and depuration of uranium, cesium and thorium in snails (Cantareus aspersus) using kinetics models

Energy Technology Data Exchange (ETDEWEB)

Pauget, B., E-mail: benjamin.pauget@tesora.fr [Tésora, Le Visium, 22 Av. Aristide Briand, 94110 Arcueil (France); Andra, R& D Division, Centre de Meuse/Haute-Marne, RD 960, 55290 Bure (France); University of Bourgogne Franche-Comté, Department Chrono-Environnement, UMR UFC/CNRS 6249, 16 Route de Gray, 25030 Besançon Cedex (France); Villeneuve, A.; Redon, P.O. [Tésora, Le Visium, 22 Av. Aristide Briand, 94110 Arcueil (France); Cuvier, A. [ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse (France); IRSN/PRP-ENV/SESURE/Laboratoire d’études radioécologiques en milieu continental et marin, BP 1, 13108 Saint-Paul-lès-Durance Cedex (France); Vaufleury, A. de [University of Bourgogne Franche-Comté, Department Chrono-Environnement, UMR UFC/CNRS 6249, 16 Route de Gray, 25030 Besançon Cedex (France)

2017-08-05

Highlights: • Kinetic studies allow to take into account the dynamic mechanisms of bioavailability. • An absence of Cs and Th accumulation is evidenced showing their low bioavailability. • The uranium accumulation is not only a function of the soil contamination. - Abstract: Uranium ore waste has led to soil contamination that may affect both environmental and soil health. To analyze the risk of metal transfer, metal bioavailability must be estimated by measuring biological parameters. Kinetic studies allow taking into account the dynamic mechanisms of bioavailability, as well as the steady state concentration in organisms necessary to take into account for relevant risk assessment. In this way, this work aims to model the snail accumulation and excretion kinetics of uranium (U), cesium (Cs) and thorium (Th). Results indicate an absence of Cs and Th accumulation showing the low bioavailability of these two elements and a strong uranium accumulation in snails related to the levels of soil contamination. During the depuration phase, most of the uranium ingested was excreted by the snails. After removing the source of uranium by soil remediation, continued snails excretion of accumulated uranium would lead to the return of their initial internal concentration, thus the potential trophic transfer of this hazardous element would stop.

Assessment of the bioavailability and depuration of uranium, cesium and thorium in snails (Cantareus aspersus) using kinetics models

International Nuclear Information System (INIS)

Pauget, B.; Villeneuve, A.; Redon, P.O.; Cuvier, A.; Vaufleury, A. de

2017-01-01

Highlights: • Kinetic studies allow to take into account the dynamic mechanisms of bioavailability. • An absence of Cs and Th accumulation is evidenced showing their low bioavailability. • The uranium accumulation is not only a function of the soil contamination. - Abstract: Uranium ore waste has led to soil contamination that may affect both environmental and soil health. To analyze the risk of metal transfer, metal bioavailability must be estimated by measuring biological parameters. Kinetic studies allow taking into account the dynamic mechanisms of bioavailability, as well as the steady state concentration in organisms necessary to take into account for relevant risk assessment. In this way, this work aims to model the snail accumulation and excretion kinetics of uranium (U), cesium (Cs) and thorium (Th). Results indicate an absence of Cs and Th accumulation showing the low bioavailability of these two elements and a strong uranium accumulation in snails related to the levels of soil contamination. During the depuration phase, most of the uranium ingested was excreted by the snails. After removing the source of uranium by soil remediation, continued snails excretion of accumulated uranium would lead to the return of their initial internal concentration, thus the potential trophic transfer of this hazardous element would stop.

Comparative bioavailability of a morphine suppository given rectally and in a colostomy

DEFF Research Database (Denmark)

Højsted, J; Rubeck-Petersen, K; Rask, H

1990-01-01

In eight patients with a colostomy, plasma morphine levels were followed for 8 h after administration of 20 mg morphine chloride as a suppository, first rectally and after at least 48 h via the colostomy. The bioavailability after administration in the colostomy showed very great variation......; the mean value compared to rectal bioavailability was only 43% (range 0.1-127%). In four patients the plasma concentrations of morphine after colostomy administration were lower at all times than after rectal administration, and in three only small amounts of morphine were detectable. One patient showed...... higher plasma concentrations after colostomy application than after rectal administration. It is concluded that administration of morphine suppositories in a colostomy cannot be recommended....

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

Science.gov (United States)

Robertson, Ian B.; Rifkin, Daniel B.

2016-01-01

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

An overview of BORIS: Bioavailability of Radionuclides in Soils

International Nuclear Information System (INIS)

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

2008-01-01

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

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.

An overview of BORIS: Bioavailability of Radionuclides in Soils

Energy Technology Data Exchange (ETDEWEB)

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

2008-05-15

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

Bioavailability of Cd in 110 polluted topsoils to recombinant bioluminescent sensor bacteria. Effect of soil particulate matter

Energy Technology Data Exchange (ETDEWEB)

Ivask, Angela; Pollumaa, Lee; Kahru, Anne [National Inst. of Chemical Physics and Biophysics, Lab. of Molecular Genetics, Tallin (Estonia); Dubourguier, Henri-Charles [National Inst. of Chemical Physics and Biophysics, Lab. of Molecular Genetics, Tallin (Estonia); Estonian Univ. of Life Sciences, Tartu (Estonia); Inst. Superieur d' Agriculture, Lille (France)

2011-02-15

In this study, bioavailability and water extractability of Cd in a panel of 110 natural aged heavy metal-polluted soils from northern France containing up to 20.1 mg of Cd per kilogramme was evaluated. Materials and methods Particulate matter was removed by differential centrifugation of soil-water suspensions (liquid to solid ratio 10) resulting in soil-water extracts containing different size of particles. Chemical analysis of Cd and analysis of bioavailable Cd with recombinant bioluminescent Cd-sensing bacteria were applied in parallel to these fractionated soil solutions. Results and Discussion Extractability of Cd from soil to the aqueous phase was low-only 0.13% of the soil total Cd as a mean; however, Cd-sensing recombinant luminescent bacteria Bacillus subtilis incubated in soil-water suspensions for 2 h showed that in the conditions of contact exposure, the bioavailable fraction of Cd increased about 30-fold being 3.74% of the soil total Cd as a mean value. The total Cd content of soils was not a good predictor of either bioavailable or water-extracted fraction of Cd, but these fractions were rather determined by the combination of soil total Cd and physico-chemical properties-texture and organic matter content. Analysis of two selected ''model'' soils with Cd sensor bacteria showed that about 90% of the bioavailable Cd was associated with larger soil particles that were removed from the soil suspensions by centrifugation at 4,500 x g, and even settling of the soil suspensions for 2 h removed already 65% of bioavailable Cd. Conclusions Thus, our results indicate a potential for remarkably higher environmental hazard for soil-associated heavy metals than just aqueous exposure. (orig.)

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

Science.gov (United States)

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

2017-04-01

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

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

Science.gov (United States)

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

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

Indian Academy of Sciences (India)

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

Measurement, analysis and prediction of topical UV filter bioavailability.

Science.gov (United States)

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

2015-01-30

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

Role of Marine Snows in Microplastic Fate and Bioavailability.

Science.gov (United States)

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

2018-06-01

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

The effect of earthworms on the fractionation and bioavailability of heavy metals before and after soil remediation

International Nuclear Information System (INIS)

Udovic, Metka; Lestan, Domen

2007-01-01

The effect of two earthworm species, Lumbricus rubellus and Eisenia fetida, on the fractionation/bioavailability of Pb and Zn before and after soil leaching with EDTA was studied. Four leaching steps with total 12.5 mmol kg -1 EDTA removed 39.8% and 6.1% of Pb and Zn, respectively. EDTA removed Pb from all soil fractions fairly uniformly (assessed using sequential extractions). Zn was mostly present in the chemically inert residual soil fraction, which explains its poor removal. Analysis of earthworm casts and the remainder of the soil indicated that L. rubellus and E. fetida actively regulated soil pH, but did not significantly change Pb and Zn fractionation in non-remediated and remediated soil. However, the bioavailability of Pb (assessed using Ruby's physiologically based extraction test) in E. fetida casts was significantly higher than in the bulk of the soil. In remediated soil the Pb bioavailability in the simulated stomach phase increased by 5.1 times. - Earthworm activity increases heavy metal bioavailability in soil before and after remediation

The effect of earthworms on the fractionation and bioavailability of heavy metals before and after soil remediation

Energy Technology Data Exchange (ETDEWEB)

Udovic, Metka [Agronomy Department, Centre for Soil and Environmental Science, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana (Slovenia); Lestan, Domen [Agronomy Department, Centre for Soil and Environmental Science, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana (Slovenia)]. E-mail: domen.lestan@bf.uni-lj.si

2007-07-15

The effect of two earthworm species, Lumbricus rubellus and Eisenia fetida, on the fractionation/bioavailability of Pb and Zn before and after soil leaching with EDTA was studied. Four leaching steps with total 12.5 mmol kg{sup -1} EDTA removed 39.8% and 6.1% of Pb and Zn, respectively. EDTA removed Pb from all soil fractions fairly uniformly (assessed using sequential extractions). Zn was mostly present in the chemically inert residual soil fraction, which explains its poor removal. Analysis of earthworm casts and the remainder of the soil indicated that L. rubellus and E. fetida actively regulated soil pH, but did not significantly change Pb and Zn fractionation in non-remediated and remediated soil. However, the bioavailability of Pb (assessed using Ruby's physiologically based extraction test) in E. fetida casts was significantly higher than in the bulk of the soil. In remediated soil the Pb bioavailability in the simulated stomach phase increased by 5.1 times. - Earthworm activity increases heavy metal bioavailability in soil before and after remediation.

Bioavailability of rifampicin following concomitant administration of ethambutol or isoniazid or pyrazinamide or a combination of the three drugs.

Science.gov (United States)

Immanuel, Chandra; Gurumurthy, Prema; Ramachandran, Geetha; Venkatesan, P; Chandrasekaran, V; Prabhakar, R

2003-09-01

Poor bioavailability of rifampicin (R) in combination with other anti-tuberculosis drugs such as isoniazid (H), pyrazinamide (Z), and ethambutol (E) is a subject of much concern for the last few decades. This could be due to an interaction between R and other drugs. An investigation was therefore undertaken to examine the bioavailability of R in the presence of H, Z and E or a combination of the three drugs. The study included eight healthy volunteers, each being investigated on four occasions at weekly intervals once with R alone and with three of the four combinations on the three remaining occasions. A partially balanced incomplete block design was employed and the allocation of R or the drug combinations was random. Plasma concentrations of R at intervals up to 12 h were determined by microbiological assay using Staphylococcus aureus as the test organism. The proportion (%) dose of R as R plus desacetyl R (DR) in urine excreted over the periods 0-8 and 8-12 h was also determined. Bioavailability was expressed as an index (BI) of area under time concentration curve (AUC) calculated from the plasma concentrations or proportion of dose of R excreted as R plus DR in urine with the combinations to that with R alone. The bioavailability indices based on AUC were 0.96 with RE, 0.76 with RH, 1.08 with RZ and 0.65 with REHZ. The indices based on urine estimations (0-8 h) were similar, the values being 0.94, 0.84, 0.94 and 0.75, respectively. A second investigation revealed that the decrease of bioavailability of R with H was not due to the excipients present in H tablets. Isoniazid alone or in combination with E and Z reduces the bioavailability of R. Urinary excretion data offer a simple and non invasive method for the assessment of bioavailability of R.

Migration and bioavailability of 137Cs in forest soil of southern Germany

International Nuclear Information System (INIS)

Konopleva, I.; Klemt, E.; Konoplev, A.; Zibold, G.

2009-01-01

To give a quantitative description of the radiocaesium soil-plant transfer for fern (Dryopteris carthusiana) and blackberry (Rubus fruticosus), physical and chemical properties of soils in spruce and mixed forest stands were investigated. Of special interest was the selective sorption of radiocaesium, which was determined by measuring the Radiocaesium Interception Potential (RIP). Forest soil and plants were taken at 10 locations of the Altdorfer Wald (5 sites in spruce forest and 5 sites in mixed forest). It was found that the bioavailability of radiocaesium in spruce forest was on average seven times higher than in mixed forest. It was shown that important factors determining the bioavailability of radiocaesium in forest soil were its exchangeability and the radiocaesium interception potential (RIP) of the soil. Low potassium concentration in soil solution of forest soils favors radiocaesium soil-plant transfer. Ammonium in forest soils plays an even more important role than potassium as a mobilizer of radiocaesium. The availability factor - a function of RIP, exchangeability and cationic composition of soil solution - characterized reliably the soil-plant transfer in both spruce and mixed forest. For highly organic soils in coniferous forest, radiocaesium sorption at regular exchange sites should be taken into account when its bioavailability is considered

Pharmacokinetic study of benfotiamine and the bioavailability assessment compared to thiamine hydrochloride.

Science.gov (United States)

Xie, Feifan; Cheng, Zeneng; Li, Sanwang; Liu, Xingling; Guo, Xin; Yu, Peng; Gu, Zhenkun

2014-06-01

Benfotiamine is a lipid-soluble thiamine precursor which can transform to thiamine in vivo and subsequently be metabolized to thiamine monophosphate (TMP) and thiamine diphosphate (TDP). This study investigated the pharmacokinetic profiles of thiamine and its phosphorylated metabolites after single- and multiple-dose administration of benfotiamine in healthy Chinese volunteers, and assessed the bioavailability of orally benfotiamine administration compared to thiamine hydrochloride. In addition, concentration of hippuric acid in urine which is produced in the transformation process of benfotiamine was determined. The results showed that thiamine and its phosphorylated metabolites exhibited different pharmacokinetic characteristics in plasma, blood and erythrocyte, and one-compartment model provided the best fit for pharmacokinetic profiles of thiamine. The transformation process of benfotiamine to thiamine produced large amount of hippuric acid. No accumulation of hippuric acid was observed after multiple-dose of benfotiamine. Compared to thiamine hydrochloride, the bioavailability of thiamine in plasma and TDP in erythrocyte after oral administration of benfotiamine were 1147.3 ± 490.3% and 195.8 ± 33.8%, respectively. The absorption rate and extent of benfotiamine systemic availability of thiamine were significantly increased indicating higher bioavailability of thiamine from oral dose of benfotiamine compared to oral dose of thiamine hydrochloride. © 2014, The American College of Clinical Pharmacology.

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.

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

Science.gov (United States)

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

2016-07-01

Mining and smelting activities have contaminated the environment with trace metals (TMs) at a worldwide scale for at least two millennia. A combination of chemical approaches and active biomonitoring was performed to analyse the environmental availability and bioavailability of TM palaeo-pollution in a former PbAg mining district in the Vosges Mountains, France. Along a soil TM contamination gradient that covered eight stations, including two archaeological mining sites, the toxicokinetics of six TMs (Pb, Cd, As, Ag, Co, Sb) in the snail Cantareus aspersus revealed that palaeo-pollution from the studied sites remains bioavailable. This study provides the first data on the accumulation kinetics of Ag and Co for C. aspersus. The environmental availability of the TMs was estimated with three chemical extraction methods (aqua regia, EDTA 50 mM, CaCl2 10 mM). Univariate regression analyses showed that EDTA extraction is the best method for estimating the bioavailability of Pb, As, Ag, Co and Sb to snails. None of the three extractants was efficient for Cd. A multivariate analysis of bioaccumulation data revealed that TM bioavailability and transfer were modulated by exposure sources (soil, humus and vegetation) rather than by soil physico-chemical characteristics. Hence, although the deposition of mining wastes dates back several centuries, these wastes still represent a source of contamination that must be considered to develop relevant site management and environmental risk assessment. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Fabrication and Optimization of Self-Microemulsions to Improve the Oral Bioavailability of Total Flavones of Hippophaë rhamnoides L.

Science.gov (United States)

Guo, Ruixue; Guo, Xinbo; Hu, Xiaodan; Abbasi, Arshad Mehmood; Zhou, Lin; Li, Tong; Fu, Xiong; Liu, Rui Hai

2017-12-01

The purpose of this work was to improve the oral bioavailability of a poorly soluble functional food ingredient, the total flavones of Hippophaë rhamnoides L. (TFH). A self-microemulsion drug delivery system (SMEDDS) was developed to overcome the problems of poor absorption of TFH in vivo. The optimal SMEDDS significantly enhanced the solubility of TFH up to 530 times compared to that in water. The mean droplet size was 61.76 nm with uniform distribution. And the loaded system was stable at 25 °C for 3 mo with transparent appearance. The in vitro release of TFH from SMEDDS was faster and more complete than that from suspension. After oral administration of TFH-SMEDDS in rats, the relative bioavailability of TFH was dramatically improved for 3.09 times compared with the unencapsulated form. The investigation indicated the potential application of SMEDDS as a vehicle to improve the oral bioavailability of TFH. The lipid-based nanotechnology, namely self-microemulsion drug delivery system (SMEDDS) was used to improve the bioavailability and oral delivery of total flavones of Hippophaë rhamnoides L. (TFH). The relevant bioavailability of TFH could be remarkably 3-fold improved by the optimized SMEDDS. The SMEDDS produced via a simple one-step process for poorly soluble TFH to achieve a significant improvement in the bioavailability, may endorse the promising utilization of TFH in functional foods as well as pharmaceutical fields with an enhanced absorption in vivo. © 2017 Institute of Food Technologists®.

In Vitro Bioavailability of Calcium, Magnesium, Iron, Zinc, and Copper from Gluten-Free Breads Supplemented with Natural Additives.

Science.gov (United States)

Regula, J; Cerba, A; Suliburska, J; Tinkov, A A

2018-03-01

The aim of this study was to measure the content of calcium, magnesium, iron, zinc, and copper and determine the bioavailability of these ingredients in gluten-free breads fortified with milk and selected seeds. Due to the increasing prevalence of celiac disease and mineral deficiencies, it has become necessary to produce food with higher nutritional values which maintains the appropriate product characteristics. This study was designed for gluten-free breads fortified with milk and seeds such as flax, poppy, sunflower seeds, pumpkin seeds or nuts, and flour with amaranth. Subsequently, digestion was performed in vitro and the potential bioavailability of the minerals was measured. In the case of calcium, magnesium, iron, and copper, higher bioavailability was observed in rice bread, and, in the case of copper and zinc, in buckwheat bread. This demonstrated a clear increase in bioavailability of all the minerals when the bread were enriched. However, satisfactory results are obtained only for the individual micronutrients.

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

Science.gov (United States)

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

2014-08-15

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2006-06-15

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

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

International Nuclear Information System (INIS)

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

1987-01-01

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

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

Science.gov (United States)

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

2018-02-01

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

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

Science.gov (United States)

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

2016-01-01

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

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

DEFF Research Database (Denmark)

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

2012-01-01

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

Optimization of caseinate-coated simvastatin-zein nanoparticles: improved bioavailability and modified release characteristics.

Science.gov (United States)

Ahmed, Osama A A; Hosny, Khaled M; Al-Sawahli, Majid M; Fahmy, Usama A

2015-01-01

The current study focuses on utilization of the natural biocompatible polymer zein to formulate simvastatin (SMV) nanoparticles coated with caseinate, to improve solubility and hence bioavailability, and in addition, to modify SMV-release characteristics. This formulation can be utilized for oral or possible depot parenteral applications. Fifteen formulations were prepared by liquid-liquid phase separation method, according to the Box-Behnken design, to optimize formulation variables. Sodium caseinate was used as an electrosteric stabilizer. The factors studied were: percentage of SMV in the SMV-zein mixture (X1), ethanol concentration (X2), and caseinate concentration (X3). The selected dependent variables were mean particle size (Y1), SMV encapsulation efficiency (Y2), and cumulative percentage of drug permeated after 1 hour (Y3). The diffusion of SMV from the prepared nanoparticles specified by the design was carried out using an automated Franz diffusion cell apparatus. The optimized SMV-zein formula was investigated for in vivo pharmacokinetic parameters compared with an oral SMV suspension. The optimized nanosized SMV-zein formula showed a 131 nm mean particle size and 89% encapsulation efficiency. In vitro permeation studies displayed delayed permeation characteristics, with about 42% and 85% of SMV cumulative amount released after 12 and 48 hours, respectively. Bioavailability estimation in rats revealed an augmentation in SMV bioavailability from the optimized SMV-zein formulation, by fourfold relative to SMV suspension. Formulation of caseinate-coated SMV-zein nanoparticles improves the pharmacokinetic profile and bioavailability of SMV. Accordingly, improved hypolipidemic activities for longer duration could be achieved. In addition, the reduced dosage rate of SMV-zein nanoparticles improves patient tolerability and compliance.

Oral administration of amphotericin B nanoparticles: antifungal activity, bioavailability and toxicity in rats.

Science.gov (United States)

Radwan, Mahasen A; AlQuadeib, Bushra T; Šiller, Lidija; Wright, Matthew C; Horrocks, Benjamin

2017-11-01

Amphotericin B (AMB) is used most commonly in severe systemic life-threatening fungal infections. There is currently an unmet need for an efficacious (AMB) formulation amenable to oral administration with better bioavailability and lower nephrotoxicity. Novel PEGylated polylactic-polyglycolic acid copolymer (PLGA-PEG) nanoparticles (NPs) formulations of AMB were therefore studied for their ability to kill Candida albicans (C. albicans). The antifungal activity of AMB formulations was assessed in C. albicans. Its bioavalability was investigated in nine groups of rats (n = 6). Toxicity was examined by an in vitro blood hemolysis assay, and in vivo nephrotoxicity after single and multiple dosing for a week by blood urea nitrogen (BUN) and plasma creatinine (PCr) measurements. The MIC of AMB loaded to PLGA-PEG NPs against C. albicans was reduced two to threefold compared with free AMB. Novel oral AMB delivery loaded to PLGA-PEG NPs was markedly systemically available compared to Fungizone® in rats. The addition of 2% of GA to the AMB formulation significantly (p bioavailability from 1.5 to 10.5% and the relative bioavailability was > 790% that of Fungizone®. The novel AMB formulations showed minimal toxicity and better efficacy compared to Fungizone®. No nephrotoxicity in rats was detected after a week of multiple dosing of AMB NPs based on BUN and PCr, which remained at normal levels. An oral delivery system of AMB-loaded to PLGA-PEG NPs with better efficacy and minimal toxicity was formulated. The addition of glycyrrhizic acid (GA) to AMB NPs formulation resulted in a significant oral absorption and improved bioavailability in rats.

Enhanced Oral Bioavailability of Pueraria Flavones by a Novel Solid Self-microemulsifying Drug Delivery System (SMEDDS) Dropping Pills.

Science.gov (United States)

Guan, Qingxiang; Zhang, Guangyuan; Sun, Shilin; Fan, Hongbo; Sun, Cheng; Zhang, Shaoyuan

2016-05-01

To improve bioavailability of pueraria flavones (PF), a self-microemulsifying drug delivery system (SMEDDS) dropping pills composed of PF, Crodamol GTCC, Maisine 35-1, Cremophor RH 40, 1,2-propylene glycol and polyethylene glycol 6000 (PEG6000) was developed. Particle size, zeta potential, morphology and in vitro drug release were investigated, respectively. Pharmacokinetics, bioavailability of PF-SMEDDS dropping pills and commercial Yufengningxin dropping pills were also evaluated and compared in rats. Puerarin treated as the representative component of PF was analyzed. Dynamic light scattering showed the ability of PF-SMEDDS dropping pills to form a nanoemulsion droplet size in aqueous media. The type of media showed no significant effects on the release rate of PF. PF-SMEDDS dropping pills were able to improve the in vitro release rate of PF, and the in vitro release of these dropping pills was significantly faster than that of Yufengningxin dropping pills. There was a dramatic difference between the mean value of t1/2, peak concentration (Cmax), the area of concentration-time curve from 0 to 6 h (AUC0-6 h) of PF-SMEDDS dropping pills and that of commercial Yufengningxin dropping pills. A pharmacokinetic study showed that the bioavailability of PF was greatly enhanced by PF-SMEDDS dropping pills. The value of Cmax and relative bioavailability of PF-SMEDDS dropping pills were dramatically improved by an average of 1.69- and 2.36-fold compared with that of Yufengningxin dropping pills after gavage administration, respectively. It was concluded that bioavailability of PF was greatly improved and that PF-SMEDDS dropping pills might be an encouraging strategy to enhance the oral bioavailability of PF.

Enhanced oral bioavailability and controlled release of dutasteride by a novel dry elixir.

Science.gov (United States)

Jang, Dong-Jin; Kim, Sung Tae; Oh, Euichaul; Ban, Eunmi

2014-01-01

To develop a solid dosage form of dutasteride for improving its oral bioavailability, a novel dry elixir (DE) system was fabricated. DEs incorporating dextrin and/or xanthan gum were prepared using spray-drying and evaluated by morphology, ethanol content, crystallinity, dissolution and oral bioavailability. DEs were spherical with a smooth surface and had an average particle size of 20-25 μm. The ethanol content could be easily varied by controlling the spray-drying temperature. The dissolution profiles of dutasteride from each DE proved to be much faster than that of dutasteride powder due to the amorphous state and a high amount of incorporated ethanol. In particular, the pharmacokinetic profiles of dutasteride were significantly altered depending on the proportions of dextrin and xanthan gum. Blood concentrations of dutasteride from DE formulations were similar to those of market products and much greater than those of native dutasteride. Interestingly, the dissolution and pharmacokinetic profiles were easily controlled by changing the ratio of dextrin to xanthan gum. The data suggests that a DE using dextrin and/or xanthan gum could provide an applicable solid dosage form to improve the dissolution and bio-availability of dutasteride as well as to modulate its pharmacokinetics.

Stabilizing Agents for Drug Nanocrystals: Effect on Bioavailability

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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.

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

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Simona Dinicola

2017-10-01

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

Supramolecular Complexation of Carbohydrates for the Bioavailability Enhancement of Poorly Soluble Drugs.

Science.gov (United States)

Cho, Eunae; Jung, Seunho

2015-10-27

In this review, a comprehensive overview of advances in the supramolecular complexes of carbohydrates and poorly soluble drugs is presented. Through the complexation process, poorly soluble drugs could be efficiently delivered to their desired destinations. Carbohydrates, the most abundant biomolecules, have diverse physicochemical properties owing to their inherent three-dimensional structures, hydrogen bonding, and molecular recognition abilities. In this regard, oligosaccharides and their derivatives have been utilized for the bioavailability enhancement of hydrophobic drugs via increasing the solubility or stability. By extension, polysaccharides and their derivatives can form self-assembled architectures with poorly soluble drugs and have shown increased bioavailability in terms of the sustained or controlled drug release. These supramolecular systems using carbohydrate will be developed consistently in the field of pharmaceutical and medical application.

Bioavailability and effects of non-ionic organic pesticides in soil

NARCIS (Netherlands)

Ronday, R.

1995-01-01

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

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

Indian Academy of Sciences (India)

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

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.

Bioavailability of residual polycyclic aromatic hydrocarbons following enhanced natural attenuation of creosote-contaminated soil

International Nuclear Information System (INIS)

Juhasz, Albert L.; Smith, Euan; Waller, Natasha; Stewart, Richard; Weber, John

2010-01-01

The impact of residual PAHs (2250 ± 71 μg total PAHs g -1 ) following enhanced natural attenuation (ENA) of creosote-contaminated soil (7767 ± 1286 μg total PAHs g -1 ) was assessed using a variety of ecological assays. Microtox TM results for aqueous soil extracts indicated that there was no significant difference in EC 50 values for uncontaminated, pre- and post-remediated soil. However, in studies conducted with Eisenia fetida, PAH bioaccumulation was reduced by up to 6.5-fold as a result of ENA. Similarly, Beta vulgaris L. biomass yields were increased 2.1-fold following ENA of creosote-contaminated soil. While earthworm and plant assays indicated that PAH bioavailability was reduced following ENA, the residual PAH fraction still exerted toxicological impacts on both receptors. Results from this study highlight that residual PAHs following ENA (presumably non-bioavailable to bioremediation) may still be bioavailable to important receptor organisms such as earthworms and plants. - Residual PAHs in creosote-contaminated soil following enhanced natural attenuation impacted negatively on ecological receptors.

Role of the decreased nitric oxide bioavailability in the vascular complications of diabetes mellitus.

Science.gov (United States)

Masha, Andi; Dinatale, Stefano; Allasia, Stefano; Martina, Valentino

2011-09-01

This mini-review takes into consideration the physiology, synthesis and mechanisms of action of the nitric oxide (NO) and, subsequently, the causes and effects of the NO bioavailability impairment. In diabetes mellitus the reduced NO bioavailability is caused by the increased free radicals production, secondary to hyperglycemia. The reactive oxygen species oxidize the cofactors of the nitric oxide synthase, diminishing their active forms and consequently leading to a decreased NO production. Furthermore the decreased concentration of reduced glutathione results in a diminished production of nitrosoglutathione. These molecules are important intermediates of the NO pathway and physiologically activate the soluble guanylate cyclase. Their decrease in oxidative states of the cell, therefore, leads to a reduced cGMP production which represents the principal molecule that carries out NO's major effects. Finally we considered the eventual therapeutic strategies to improve NO bioavailability by acting on the causes of its decrease. Therefore the treatments proposed are based on the possibility to counteract the oxidation and, in this context, the physiopathological mechanisms strongly support the treatment with thiols.

Elevating bioavailability of cyclosporine a via encapsulation in artificial oil bodies stabilized by caleosin.

Science.gov (United States)

Chen, Miles C M; Wang, Jui-Ling; Tzen, Jason T C

2005-01-01

To elevate its bioavailability via oral administration, cyclosporine A (CsA), a hydrophobic drug, was either incorporated into olive oil directly or encapsulated in artificial oil bodies (AOBs) constituted with olive oil and phospholipid in the presence or absence of recombinant caleosin purified from Escherichia coli. The bioavailabilities of CsA in these formulations were assessed in Wistar rats in comparison with the commercial formulation, Sandimmun Neoral. Among these tests, CsA-loaded AOBs stabilized by the recombinant caleosin exhibited better bioavailability than the commercial formulation and possessed the highest maximum whole blood concentration (C(max)), 1247.4 +/- 106.8 ng/mL, in the experimental animals 4.3 +/- 0.7 h (t(max)) after oral administration. C(max) and the area under the plasma concentration-time curve (AUC(0-24)) were individually increased by 50.8% and 71.3% in the rats fed with caleosin-stabilized AOBs when compared with those fed with the reference Sandimmun Neoral. The results suggest that constitution of AOBs stabilized by caleosin may be a suitable technique to encapsulate hydrophobic drugs for oral administration.

Improvement of bioavailability and anti-inflammatory potential of curcumin in combination with emu oil.

Science.gov (United States)

Jeengar, Manish Kumar; Shrivastava, Shweta; Nair, Kala; Singareddy, Sreenivasa Reddy; Putcha, Uday Kumar; Talluri, M V N Kumar; Naidu, V G M; Sistla, Ramakrishna

2014-12-01

The purpose of the present study is to evaluate the effect of emu oil on bioavailability of curcumin when co-administered and to evaluate the property that enhances the anti-inflammatory potential of curcumin. Oral bioavailability of curcumin in combination with emu oil was determined by measuring the plasma concentration of curcumin by HPLC. The anti-inflammatory potential was evaluated in carrageenan-induced paw edema model (acute model) and in Freund's complete adjuvant (FCA)-induced arthritis model (chronic model) in male SD rats. The anti-inflammatory potential of curcumin in combination with emu oil has been significantly increased in both acute and chronic inflammatory models as evident from inhibition of increase in paw volume, arthritic score, and expression of pro-inflammatory cytokines. The increased anti-inflammatory activity in combination therapy is due to enhanced bioavailability (5.2-fold compared to aqueous suspension) of curcumin by emu oil. Finally, it is concluded that the combination of emu oil with curcumin will be a promising approach for the treatment of arthritis.

Studies on the applicability of biomarkers in estimating the systematic bioavailability of polynuclear aromatic hydrocarbons from manufactured gas plant tar-contaminated soils

International Nuclear Information System (INIS)

Koganti, A.; Spina, D.A.; Rozett, K.; Ma, B.-L.; Weyand, E.; Taylor, B.B.; Mauro, D.M.

1998-01-01

The systematic bioavailability of polynuclear aromatic hydrocarbons (PAH) from ingested soils containing manufactured gas plant (MGP) tar was evaluated in mice. Soil and organic extract of each soil were incorporated into a diet and fed to mice for two weeks. 1-Hydroxypyrene levels in urine and chemical:DNA adduct levels in lungs were used as biomarkers of PAH systematic bioavailability. Estimates of PAH relative bioavailability were determined by comparing the bioavailability observed between each soil and corresponding organic extract. In all but one case, bioavailiablity estimates based on 1-hydroxypyrene levels in urine indicate that the presence of MGP tar on soil results in a considerable decrease in PAH systemic bioavailablity (9-75%). Similarly, PAH bioavailability estimates based on chemical:DNA adduct formation ranged from nondetectable to 76%. These results clearly indicate that the bioavailiablity of PAH is less than 100% when soil contaminated with MGP tar is ingested by nice. In addition, the experimental methods employed in this study appear suitable for evaluating the effects of soil on the gastrointestinal absorption and systemic bioavailability of PAH from soil containing complex organic mixtures. 44 refs., 1 fig., 5 tabs

ABSORPTION AND BIOAVAILABILITY OF THE MINERALS IN THE MULTI-MIXTURE FOOD SUPPLEMENT: BIOLOGICAL ASSAY IN RATS

Directory of Open Access Journals (Sweden)

E. HELBIG

2008-12-01

Full Text Available

The absorption and bioavailability of the minerals Ca, Fe and Zn in balanced and mineral restricted diets with the addition of the food supplement multi-mixture (MM, was evaluated. A biological assay was carried out for 28 days with recently weaned Wistar rats, using 3 treatments and 8 animals in each group. The diets offered to each group were distributed as follows: CD – Control Diet (AIN-93G; CcD/MM – Control Diet + Supplement 5% MM; DRMIXc/MM – Control Diet with Mineral Restricted + Supplement 5% MM. The animals were monitored for weight; amount of diet consumed and amount of faeces excreted. They were sacrifi ced at the end of the experimental period and the pair of femurs, pancreas and liver removed for the determination of Ca, Fe and Zn. The CcD/MM diet presented absorption of Ca and Fe and bioavailability of Ca, Fe and Zn equal to that of CD, showing no statistical difference between the treatments. However the DRMIXcD/MM diet presented an increase in Ca absorption, equal absorption of Fe and an increase in the bioavailability of Ca, Fe and Zn when compared to CD. It was concluded that when fed on a balanced diet supplemented with 5% MM, there was no increase in the bioavailability of Ca, Fe or Zn, whereas when fed on a mineral defi cient diet, the group of animals that received supplementation with 5% MM, presented greater absorption and bioavailability of these minerals.

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

Science.gov (United States)

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

2016-06-01

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

Are Lead Exposures a Risk in European Fresh Waters? A Regulatory Assessment Accounting for Bioavailability.

Science.gov (United States)

Peters, Adam; Wilson, Iain; Merrington, Graham; Chowdhury, M Jasim

2018-01-01

An indicative compliance assessment of the Europe-wide bioavailable lead Environmental Quality Standard of 1.2 µg L -1 (EQS) was undertaken against regulatory freshwater monitoring data from six European member states and FOREGS database. Bio-met, a user-friendly tool based upon Biotic Ligand Models (BLMs) was used to account for bioavailability, along with the current European Water Framework Directive lead dissolved organic carbon correction approach. The outputs from both approaches were compared to the BLM. Of the 9054 freshwater samples assessed only 0.6% exceeded the EQS of 1.2 µg L -1 after accounting for bioavailability. The data showed that ambient background concentrations of lead across Europe are unlikely to influence general compliance with the EQS, although there may be isolated local issues. The waters showing the greatest sensitivity to potential lead exposures are characterized by relatively low DOC (< 0.5 mg L -1 ), regardless of the pH and calcium concentrations.

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

Science.gov (United States)

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

2017-06-19

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

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

Science.gov (United States)

Yan, Lin; Johnson, LuAnn K

2011-06-08

This study determined the bioavailability of selenium (Se) from yellow peas and oats harvested from the high-Se soil of South Dakota, United States. The Se concentrations were 13.5 ± 0.2 and 2.5 ± 0.1 mg/kg (dry weight) for peas and oats, respectively. Male weanling Sprague-Dawley rats were depleted of Se by feeding them a 30% Torula yeast-based diet (4.1 μg Se/kg) for 56 days, and then they were replenished with Se for an additional 50 days by feeding them the same diet supplemented with 20, 30, or 40 μg Se/kg from peas or oats, respectively. Selenium bioavailability was determined on the basis of the restoration of Se-dependent enzyme activities and tissue Se concentrations in Se-depleted rats, comparing those responses for yellow peas and oats to those for l-selenomethionine (SeMet; used as a reference) by using a slope-ratio method. Dietary supplementation with peas or oats resulted in linear or log-linear, dose-dependent increases in glutathione peroxidase activities in blood and liver and in thioredoxin reductase activity in liver. Supplementation with peas or oats resulted in linear or log-linear, dose-dependent increases in Se concentrations of plasma, liver, gastrocnemius muscle, and kidneys. The overall bioavailability was approximately 88% for Se from yellow peas and 92% from oats, compared to SeMet. It was concluded that Se from naturally produced high-Se yellow peas or oats is highly bioavailable in this model and that these high-Se foods may be a good dietary source of Se.

Improving the relationship between soil characteristics and metal bioavailability by using reactive fractions of soil parameters in calcareous soils.

Science.gov (United States)

de Santiago-Martín, Ana; van Oort, Folkert; González, Concepción; Quintana, José R; Lafuente, Antonio L; Lamy, Isabelle

2015-01-01

The contribution of the nature instead of the total content of soil parameters relevant to metal bioavailability in lettuce was tested using a series of low-polluted Mediterranean agricultural calcareous soils offering natural gradients in the content and composition of carbonate, organic, and oxide fractions. Two datasets were compared by canonical ordination based on redundancy analysis: total concentrations (TC dataset) of main soil parameters (constituents, phases, or elements) involved in metal retention and bioavailability; and chemically defined reactive fractions of these parameters (RF dataset). The metal bioavailability patterns were satisfactorily explained only when the RF dataset was used, and the results showed that the proportion of crystalline Fe oxides, dissolved organic C, diethylene-triamine-pentaacetic acid (DTPA)-extractable Cu and Zn, and a labile organic pool accounted for 76% of the variance. In addition, 2 multipollution scenarios by metal spiking were tested that showed better relationships with the RF dataset than with the TC dataset (up to 17% more) and new reactive fractions involved. For Mediterranean calcareous soils, the use of reactive pools of soil parameters rather than their total contents improved the relationships between soil constituents and metal bioavailability. Such pool determinations should be systematically included in studies dealing with bioavailability or risk assessment. © 2014 SETAC.

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

NARCIS (Netherlands)

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

2003-01-01

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

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...

Seasonal change of non-point source pollution-induced bioavailable phosphorus loss: A case study of Southwestern China

Science.gov (United States)

Gao, Yang; Zhu, Bo; Wang, Tao; Wang, Yafeng

2012-02-01

SummaryBioavailable phosphorus (P) losses due to agriculture activity in a purple soil watershed in the Sichuan Basin of Southwestern China were monitored to define the hydrological controls of P transport. Our results indicate that the proportion of P that was transported in particulate form increased in the rainy season, and that the mass of total bioavailable P (BAP) loads exhibited seasonal fluctuations, wherein the majority (over 90%) was observed to have been exported between June and September. The proportion of bioavailable dissolved P (BDP) in the BAP discharge budget in the watershed varied between 11% and 15% during the monitoring period. The bioavailable particulate P (BPP) and BDP concentrations of stream water under rainstorm events increased by over 40% in comparison to their annual mean concentrations, and the annual BAP load was primarily dominated by the loads that occurred during rainstorm events in the study year. BAP concentration in groundwater significantly fluctuated with the seasons, and the ratio of total BAP in groundwater to that in surface water gradually increased during the rainy season. Thus, the impact of agriculture on the water quality of this watershed becomes clearly evident.

Biocompatible nanoemulsions based on hemp oil and less surfactants for oral delivery of baicalein with enhanced bioavailability.

Science.gov (United States)

Yin, Juntao; Xiang, Cuiyu; Wang, Peiqing; Yin, Yuyun; Hou, Yantao

2017-01-01

Baicalein (BCL) possesses high pharmacological activities but low solubility and stability in the intestinal tract. This study aimed to probe the potential of nanoemulsions (NEs) consisting of hemp oil and less surfactants in ameliorating the oral bioavailability of BCL. BCL-loaded NEs (BCL-NEs) were prepared by high-pressure homogenization technique to reduce the amount of surfactants. BCL-NEs were characterized by particle size, entrapment efficiency (EE), in vitro drug release, and morphology. Bioavailability was studied in Sprague-Dawley rats following oral administration of BCL suspensions, BCL conventional emulsions, and BCL-NEs. The obtained NEs were ~90 nm in particle size with an EE of 99.31%. BCL-NEs significantly enhanced the oral bioavailability of BCL, up to 524.7% and 242.1% relative to the suspensions and conventional emulsions, respectively. BCL-NEs exhibited excellent intestinal permeability and transcellular transport ability. The cytotoxicity of BCL-NEs was documented to be low and acceptable for oral purpose. Our findings suggest that such novel NEs and preparative process provide a promising alternative to current formulation technologies and suitable for oral delivery of drugs with bioavailability issues.

Final Report for Project ''Role of Metal Bioavailability in In Situ Bioremediation of Metal and Organic Co-Contaminated Sites''; FINAL

International Nuclear Information System (INIS)

Raina M. Maier

2002-01-01

A large proportion of hazardous waste sites are co-contaminated with organics and various metals. Such co-contaminated sites are difficult to bioremediate due to the nature of the mixed contaminants. Specifically, the presence of a co-contaminating metal imposes increased stress on indigenous populations already impacted by organic contaminant stress. The overall objective of this research is to investigate the effect of varying metal bioavailability on microbial populations and biodegradation of organics to allow a better understanding of how optimize remediation of co-contaminated sites. The hypothesis for this project is that metal bioavailability is not directly correlated with metal stress imposed on microbial populations that are degrading organics in soil and that further understanding of the relationship between metal bioavailability and metal stress is required for successful treatment of sites contaminated with mixtures of organics and metals. The specific objectives to be addressed to accomplish this goal are: (1) To determine the influence of metal bioavailability in soil microcosms co-contaminated with organics and metals on degradation of the organic contaminants and on mechanisms of metal resistance and (2) To determine the efficacy of different bioremediation strategies for co-contaminated soils based on metal bioavailability

Assessing the Dietary Bioavailability of Metals Associated with Natural Particles: Extending the Use of the Reverse Labeling Approach to Zinc.

Science.gov (United States)

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

2017-03-07

We extend the use of a novel tracing technique to quantify the bioavailability of zinc (Zn) associated with natural particles using snails enriched with a less common Zn stable isotope. Lymnaea stagnalis is a model species that has relatively fast Zn uptake rates from the dissolved phase, enabling their rapid enrichment in 67 Zn during the initial phase of labeling. Isotopically enriched snails were subsequently exposed to algae mixed with increasing amounts of metal-rich particles collected from two acid mine drainage impacted rivers. Zinc bioavailability from the natural particles was inferred from calculations of 66 Zn assimilation into the snail's soft tissues. Zinc assimilation efficiency (AE) varied from 28% for the Animas River particles to 45% for the Snake River particles, indicating that particle-bound, or sorbed Zn, was bioavailable from acid mine drainage wastes. The relative binding strength of Zn sorption to the natural particles was inversely related to Zn bioavailability; a finding that would not have been possible without using the reverse labeling approach. Differences in the chemical composition of the particles suggest that their geochemical properties may influence the extent of Zn bioavailability.

Enhanced Dissolution and Oral Bioavailability of Piroxicam Formulations: Modulating Effect of Phospholipids

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Muhammad D. Hussain

2010-10-01

Full Text Available Several biologically relevant phospholipids were assessed as potential carriers/additives for rapidly dissolving solid formulations of piroxicam (Biopharmaceutics Classification System Class II drug. On the basis of in vitro dissolution studies, dimyristoylphosphatidylglycerol (DMPG was ranked as the first potent dissolution rate enhancer for the model drug. Subsequently, the solid dispersions of varying piroxicam/DMPG ratios were prepared and further investigated. Within the concentration range studied (6.4-16.7 wt %, the dissolution rate of piroxicam from the solid dispersions appeared to increase as a function of the carrier weight fraction, whereas the cumulative drug concentration was not significantly affected by piroxicam/DMPG ratio, presumably due to a unique phase behavior of the aqueous dispersions of this carrier phospholipid. Solid state analysis of DMPG-based formulations reveled that they are two-component systems, with a less thermodynamically stable form of piroxicam (Form II being dispersed within the carrier. Finally, oral bioavailability of piroxicam from the DMPG-based formulations in rats was found to be superior to that of the control, as indicated by the bioavailability parameters, cmax and especially Tmax (53 µg/mL within 2 h vs. 39 µg/mL within 5.5 h, respectively. Hence, DMPG was regarded as the most promising carrier phospholipid for enhancing oral bioavailability of piroxicam and potentially other Class II drugs.

Double-tailed acyl glycoside niosomal nanocarrier for enhanced oral bioavailability of Cefixime.

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Imran, Muhammad; Shah, Muhammad Raza; Ullah, Farhat; Ullah, Shafi; Sadiq, Abdul; Ali, Imdad; Ahmed, Farid; Nawaz, Waqas

2017-11-01

Novel, safe, efficient, and cost effective surfactants from renewable resources has attracted attention for enhancing solubility and bioavailability of hydrophobic dugs. We report the synthesis, characterization, and biocompatibility of a novel non-ionic acyl glycoside double-tailed surfactant for niosomal drug delivery system. Structure of the surfactant was confirmed by 1 H NMR and mass spectroscopy. Applications of surfactant in niosomal drug delivery were explored using Cefixime as model. The shape, size, and polydispersity index (PDI) of drug loaded vesicles were investigated with atomic force microscope (AFM) and dynamic light scattering (DLS). Drug entrapping efficiency (EE%) was determined using HPLC. Biocompatibility of the surfactant was evaluated by in vitro cytotoxicity, blood hemolysis, and in vivo acute toxicity. Bioavailability of the surfactant based formulation was investigated in rabbits using HPLC. Vesicles were found to be 159.76 ± 6.54 nm with narrow size distribution and spherical shape. EE% was found to be 71.39 ± 3.52%. Novel surfactant was non-cytotoxicity and hemo-compatible even at 1000 μg/mL concentration and was safe up to 2000 mg/kg body weight. The in vivo bioavailability of niosomal formulation showed elevated plasma concentration and decreased clearance of Cefixime. Current findings reveal that this novel surfactant is biocompatible and could be employed for niosomal drug delivery.

Biocompatible nanoemulsions based on hemp oil and less surfactants for oral delivery of baicalein with enhanced bioavailability

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Yin J

2017-04-01

Full Text Available Juntao Yin,1,* Cuiyu Xiang,1,* Peiqing Wang,1 Yuyun Yin,2 Yantao Hou3 1Department of Pharmaceutics, Huaihe Hospital Affiliated to Henan University, Kaifeng, 2Department of Physiochemical Analysis, Henan Provincial Institute for Food and Drug Control, Zhengzhou, 3Department of Pharmaceutical Engineering, Henan Vocational College of Applied Technology, Kaifeng, People’s Republic of China *These authors contributed equally to this work Abstract: Baicalein (BCL possesses high pharmacological activities but low solubility and stability in the intestinal tract. This study aimed to probe the potential of nanoemulsions (NEs consisting of hemp oil and less surfactants in ameliorating the oral bioavailability of BCL. BCL-loaded NEs (BCL-NEs were prepared by high-pressure homogenization technique to reduce the amount of surfactants. BCL-NEs were characterized by particle size, entrapment efficiency (EE, in vitro drug release, and morphology. Bioavailability was studied in Sprague-Dawley rats following oral administration of BCL suspensions, BCL conventional emulsions, and BCL-NEs. The obtained NEs were ~90 nm in particle size with an EE of 99.31%. BCL-NEs significantly enhanced the oral bioavailability of BCL, up to 524.7% and 242.1% relative to the suspensions and conventional emulsions, respectively. BCL-NEs exhibited excellent intestinal permeability and transcellular transport ability. The cytotoxicity of BCL-NEs was documented to be low and acceptable for oral purpose. Our findings suggest that such novel NEs and preparative process provide a promising alternative to current formulation technologies and suitable for oral delivery of drugs with bioavailability issues. Keywords: baicalein, nanoemulsions, biocompatibility, high-pressure homogenization, hemp oil, bioavailability

Biodisponibilidade do licopeno Bioavailability of lycopene

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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

Copper availability and bioavailability are controlled by rhizosphere pH in rape grown in an acidic Cu-contaminated soil

International Nuclear Information System (INIS)

Chaignon, Valerie; Quesnoit, Marie; Hinsinger, Philippe

2009-01-01

We evaluated how root-induced changes in rhizosphere pH varied and interacted with Cu availability and bioavailability in an acidic soil. Rape was grown on a Cu-contaminated acidic soil, which had been limed at 10 rates. Soil Cu bioavailability was not influenced by liming. However, liming significantly decreased CaCl 2 -extracted Cu for pH between 3.7 and 5.1. Little effect was found for pH above 5.1. For soil pH 2 -Cu contents were smaller in rhizosphere than uncropped soil. Rhizosphere alkalisation occurred at pH 2 -Cu in the rhizosphere at low pH and the absence of pH dependency of Cu bioavailability to rape. In addition, apoplastic Cu in roots increased with increasing soil pH, most probably as a result of increased dissociation and affinity of cell wall compounds for Cu. - Root-induced increase in pH reduces Cu availability in the rhizosphere and Cu bioavailability to rape.

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

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

2014-10-01

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

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

International Nuclear Information System (INIS)

Chen, Haw-Wen; Huang, Chin-Shiu; Li, Chien-Chun; Lin, Ai-Hsuan; Huang, Yu-Ju; Wang, Tsu-Shing; Yao, Hsien-Tsung; Lii, Chong-Kuei

2014-01-01

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

The potential bioavailability of mineral-associated organic nitrogen in the rhizosphere.

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Jilling, A.; Grandy, S.; Keiluweit, M.

2017-12-01

Nitrogen (N) transformations and bioavailability limit both plant productivity and N losses in most ecosystems. Recent research has focused on the mineralization path that N takes—from polymeric to monomeric and finally inorganic forms—and how these pools and processes influence the bioavailability of soil N. By contrast, there has been inadequate exploration of the N-sources that dominate the production of bioavailable N. In a new conceptual framework, we propose that mineral-associated organic matter (MAOM) is an overlooked, but critical, source of organic N, especially in the rhizosphere. We hypothesize that root-deposited low molecular weight exudates enhance the direct and indirect (via microbial communities) destabilization, solubilization, and subsequent bioavailable of MAOM. To test this conceptual framework, we conducted a laboratory incubation to examine the capacity for MAOM to supply N and to determine whether the soil-microbial response to root exudates facilitates the release and subsequent degradation of mineral-bound N. We isolated silt and clay organic matter fractions from two agricultural soils and added sterile sand to create a soil in which MAOM was the sole source of organic N. We applied three solution treatments: 13C-labelled glucose, to stimulate microbial activity and potentially the production of extracellular enzymes capable of liberating N; 13C-labelled oxalic acid, which has been demonstrated to dissolve metal-organic bonds and possibly destabilize mineral-bound and N-rich organic matter; and water, to serve as a control. Over the 12-day incubation, we observed an increase in enzyme activities and C- and N-cycling rates following glucose additions. Oxalic acid additions initially suppressed microbial activity, but eventually favored a slower-growing community with greater oxidative enzyme potential. Results suggest that C additions stimulate a microbial SOM-mining response. We will further assess the abiotic effect of organic acids

Bioavailability and soil-to-crop transfer of heavy metals in farmland soils: A case study in the Pearl River Delta, South China.

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Zhang, Jingru; Li, Huizhen; Zhou, Yongzhang; Dou, Lei; Cai, Limei; Mo, Liping; You, Jing

2018-04-01

Soil-bound heavy metals are of great concern for human health due to the potential exposure via food chain transfer. In the present study, the occurrence, the bioavailability and the soil-to-crop transfer of heavy metals in farmland soils were investigated based on data from two agricultural areas, i.e. Sihui and Shunde in South China. Six heavy metals (As, Cu, Hg, Mn, Ni and Pb) were quantified in the farmland soils. The mean single pollution level indices (PI) were all lower than 1 except for Hg in soils from Shunde (PI = 1.51 ± 0.46), suggesting the farmland soils were within clean and slightly polluted by heavy metals. As, Cu, Ni and Pb were found to be mostly present in the non-bioavailable form. The majority of Hg was considered potentially bioavailable, and Mn was found to be largely bioavailable. Soil pH was an important factor influencing bioavailability of soil-bound heavy metals. The concentrations of heavy metals in vegetables from Sihui and Shunde were within the food hygiene standards, while the rice grain from Sihui was polluted by Pb (PI = 10.3 ± 23.4). Total soil concentrations of heavy metals were not correlated to their corresponding crop concentrations, instead, significant correlations were observed for bioavailable concentrations in soil. The results supported the notion that the bioavailability of the investigated heavy metals in the soil was largely responsible for their crop uptake. The soil-to-crop transfer factors based on bioavailable concentrations suggested that Cu, As and Hg in soils of the study area had greater tendency to be accumulated in the vegetables than other heavy metals, calling for further human health assessment by consuming the contaminated crops. Copyright © 2017 Elsevier Ltd. All rights reserved.

Novel electrosprayed nanospherules for enhanced aqueous solubility and oral bioavailability of poorly water-soluble fenofibrate

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Yousaf AM

2016-01-01

Full Text Available Abid Mehmood Yousaf,1,2 Omer Mustapha,1 Dong Wuk Kim,1 Dong Shik Kim,1 Kyeong Soo Kim,1 Sung Giu Jin,1 Chul Soon Yong,3 Yu Seok Youn,4 Yu-Kyoung Oh,5 Jong Oh Kim,3 Han-Gon Choi1 1College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi, South Korea; 2Faculty of Pharmacy, University of Central Punjab, Johar, Lahore, Pakistan; 3College of Pharmacy, Yeungnam University, Gyongsan, North Gyeongsang, 4School of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi, 5College of Pharmacy, Seoul National University, Seoul, South Korea Purpose: The purpose of the present research was to develop a novel electrosprayed nanospherule providing the most optimized aqueous solubility and oral bioavailability for poorly water-soluble fenofibrate.Methods: Numerous fenofibrate-loaded electrosprayed nanospherules were prepared with polyvinylpyrrolidone (PVP and Labrafil® M 2125 as carriers using the electrospray technique, and the effect of the carriers on drug solubility and solvation was assessed. The solid state characterization of an optimized formulation was conducted by scanning electron microscopy, powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopic analyses. Oral bioavailability in rats was also evaluated for the formulation of an optimized nanospherule in comparison with free drug and a conventional fenofibrate-loaded solid dispersion.Results: All of the electrosprayed nanospherule formulations had remarkably enhanced aqueous solubility and dissolution compared with free drug. Moreover, Labrafil M 2125, a surfactant, had a positive influence on the solubility and dissolution of the drug in the electrosprayed nanospherule. Increases were observed as the PVP/drug ratio increased to 4:1, but higher ratios gave no significant increases. In particular, an electrosprayed nanospherule composed of fenofibrate, PVP, and Labrafil M 2125 at the weight ratio of 1

Preparation, characterization and bioavailability by oral administration of O/W curcumin nanoemulsions stabilized with lysophosphatidylcholine.

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Chávez-Zamudio, Rubi; Ochoa-Flores, Angélica A; Soto-Rodríguez, Ida; Garcia-Varela, Rebeca; García, Hugo Sergio

2017-09-20

Curcumin is the main and most abundant bioactive component in Curcuma longa L. with documented properties in the prevention and treatment of chronic degenerative and infectious diseases. However, curcumin has low solubility in aqueous media, hence low bioavailability when administered orally. The use of nanoemulsions as carriers can provide a partial solution to bioavailability restrictions. In our study, O/W nanoemulsions of curcumin were prepared using lysophosphatidylcholine, a phospholipid with proven emulsification capacity; nevertheless, such qualities have not been previously reported in the preparation of nanoemulsions. Lysophosphatidylcholine was obtained by enzymatic removal of one fatty acid residue from phosphatidylcholine. The objective of our work was to formulate stable curcumin nanoemulsions and evaluate their bioavailability in BALB/c mice plasma after oral administration. Formulated nanoemulsions had a droplet size mean of 154.32 ± 3.10 nm, a polydispersity index of 0.34 ± 0.07 and zeta potential of -10.43 ± 1.10 mV; stability was monitored for 12 weeks. Lastly, in vivo pharmacokinetic parameters, using BALB/c mice, were obtained; namely, C max of 610 ± 65.0 μg mL -1 and T max of 2 h. Pharmacokinetic data revealed a higher bioavailability of emulsified as opposed to free curcumin. Research regarding other potential emulsifiers that may provide better health benefits and carry nano-encapsulated bioactive compounds more effectively, is necessary. This study provides important data on the preparation and design of nanoencapsulated Curcumin using lysophosphatidylcholine as an emulsifier.

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

Science.gov (United States)

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

2010-05-01

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

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

Science.gov (United States)

Hartman, Gideon; Richards, Mike

2014-02-01

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

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

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Tsin W Yeo

2010-04-01

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

Bioavailability of silver and silver sulfide nanoparticles to lettuce (Lactuca sativa): Effect of agricultural amendments on plant uptake.

Science.gov (United States)

Doolette, Casey L; McLaughlin, Michael J; Kirby, Jason K; Navarro, Divina A

2015-12-30

Silver nanoparticles (AgNPs) can enter terrestrial systems as sulfidised AgNPs (Ag2S-NPs) through the application of biosolids to soil. However, the bioavailability of Ag2S-NPs in soils is unknown. The two aims of this study were to investigate (1) the bioavailability of Ag to lettuce (Lactuca sativa) using a soil amended with biosolids containing Ag2S-NPs and (2) the effect of commonly used agricultural fertilisers/amendments on the bioavailability of Ag, AgNPs and Ag2S-NPs to lettuce. The study used realistic AgNP exposure pathways and exposure concentrations. The plant uptake of Ag from biosolids-amended soil containing Ag2S-NPs was very low for all Ag treatments (0.02%). Ammonium thiosulfate and potassium chloride fertilisation significantly increased the Ag concentrations of plant roots and shoots. The extent of the effect varied depending on the type of Ag. Ag2S-NPs, the realistic form of AgNPs in soil, had the lowest bioavailability. The potential risk of AgNPs in soils is low; even in the plants that had the highest Ag concentrations (Ag(+)+thiosulfate), only 0.06% of added Ag was found in edible plant parts (shoots). Results from the study suggest that agricultural practises must be considered when carrying out risk assessments of AgNPs in terrestrial systems; such practises can affect AgNP bioavailability. Copyright © 2015 Elsevier B.V. All rights reserved.

Chitosan-based nanoparticles for improved anticancer efficacy and bioavailability of mifepristone

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Huijuan Zhang

2016-11-01

Full Text Available In addition to its well-known abortifacient effect, mifepristone (MIF has been used as an anticancer drug for various cancers in many studies with an in-depth understanding of the mechanism of action. However, application of MIF is limited by its poor water solubility and low oral bioavailability. In this work, we developed a drug delivery system based on chitosan nanoparticles (CNs to improve its bioavailability and anticancer activity. The MIF-loaded chitosan nanoparticles (MCNs were prepared by convenient ionic gelation techniques between chitosan (Cs and tripolyphosphate (TPP. The preparation conditions, including Cs concentration, TPP concentration, Cs/MIF mass ratio, and pH value of the TPP solution, were optimized to gain better encapsulation efficiency (EE and drug loading capacity (DL. MCNs prepared with the optimum conditions resulted in spherical particles with an average size of 200 nm. FTIR and XRD spectra verified that MIF was successfully encapsulated in CNs. The EE and DL of MCNs determined by HPLC were 86.6% and 43.3%, respectively. The in vitro release kinetics demonstrated that MIF was released from CNs in a sustained-release manner. Compared with free MIF, MCNs demonstrated increased anticancer activity in several cancer cell lines. Pharmacokinetic studies in male rats that were orally administered MCNs showed a 3.2-fold increase in the area under the curve from 0 to 24 h compared with free MIF. These results demonstrated that MCNs could be developed as a potential delivery system for MIF to improve its anticancer activity and bioavailability.

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.

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

OpenAIRE

Zenei Taira, Zenei; Ueda,Yukari

2013-01-01

Yukari Ueda, Zenei TairaFaculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, JapanAbstract: We studied the absolute bioavailability of calcium from calcium L-lactate in mice using pharmacokinetics, and reviewed the absolute bioavailability of calcium from three other calcium salts in mice previously studied: calcium chloride, calcium acetate, and calcium ascorbate. The results showed that calcium metabolism is linear between intravenous administration of 15 mg/kg and 30 ...

Enhanced anticancer activity and oral bioavailability of ellagic acid through encapsulation in biodegradable polymeric nanoparticles

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Mady FM

2017-10-01

Full Text Available Fatma M Mady,1,2 Mohamed A Shaker1,3 1Pharmaceutics and Pharmaceutical Technology Department, College of Pharmacy, Taibah University, Al Madina Al Munawara, Saudi Arabia; 2Pharmaceutics Department, Faculty of Pharmacy, Minia University, Minia, 3Pharmaceutics Department, Faculty of Pharmacy, Helwan University, Cairo, Egypt Abstract: Despite the fact that various studies have investigated the clinical relevance of ellagic acid (EA as a naturally existing bioactive substance in cancer therapy, little has been reported regarding the efficient strategy for improving its oral bioavailability. In this study, we report the formulation of EA-loaded nanoparticles (EA-NPs to find a way to enhance its bioactivity as well as bioavailability after oral administration. Poly(ε-caprolactone (PCL was selected as the biodegradable polymer for the formulation of EA-NPs through the emulsion–diffusion–evaporation technique. The obtained NPs have been characterized by measuring particle size, zeta potential, Fourier transform infrared, differential scanning calorimetry, and X-ray diffraction. The entrapment efficiency and the release profile of EA was also determined. In vitro cellular uptake and cytotoxicity of the obtained NPs were evaluated using Caco-2 and HCT-116 cell lines, respectively. Moreover, in vivo study has been performed to measure the oral bioavailability of EA-NPs compared to free EA, using New Zealand white rabbits. NPs with distinct shape were obtained with high entrapment and loading efficiencies. Diffusion-driven release profile of EA from the prepared NPs was determined. EA-NP-treated HCT-116 cells showed relatively lower cell viability compared to free EA-treated cells. Fluorometric imaging revealed the cellular uptake and efficient localization of EA-NPs in the nuclear region of Caco-2 cells. In vivo testing revealed that the oral administration of EA-NPs produced a 3.6 times increase in the area under the curve compared to that of EA

Assessing the relative bioavailability of DOC in regional groundwater systems

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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.

Assessing the relative bioavailability of DOC in regional groundwater systems.

Science.gov (United States)

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

2013-01-01

It has been hypothesized that the degree to which a hyperbolic relationship exists between concentrations of dissolved organic carbon (DOC) and dissolved oxygen (DO) in groundwater may indicate the relative bioavailability of DOC. This hypothesis was examined for 73 different regional aquifers of the United States using 7745 analyses of groundwater compiled by the National Water Assessment (NAWQA) program of the U.S. Geological Survey. The relative reaction quotient (RRQ), a measure of the curvature of DOC concentrations plotted versus DO concentrations and regressed to a decaying hyperbolic equation, was used to assess the relative bioavailability of DOC. For the basalt aquifer of Oahu, Hawaii, RRQ values were low (0.0013 mM(-2)), reflecting a nearly random relationship between DOC and DO concentrations. In contrast, on the island of Maui, treated sewage effluent injected into a portion of the basalt aquifer resulted in pronounced hyperbolic DOC-DO behavior and a higher RRQ (142 mM(-2)). RRQ values for the 73 aquifers correlated positively with mean concentrations of ammonia, dissolved iron, and manganese, and correlated negatively with mean pH. This indicates that greater RRQ values are associated with greater concentrations of the final products of microbial reduction reactions. RRQ values and DOC concentrations were negatively correlated with the thickness of the unsaturated zone (UNST) and depth to the top of the screened interval. Finally, RRQ values were positively correlated with mean annual precipitation (MAP), and the highest observed RRQ values were associated with aquifers receiving MAP rates ranging between 900 and 1300 mm/year. These results are uniformly consistent with the hypothesis that the hyperbolic behavior of DOC-DO plots, as quantified by the RRQ metric, can be an indicator of relative DOC bioavailability in groundwater systems. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

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

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Wei-Lun Hung

2018-04-01

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

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

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

2015-03-01

The subcutaneous administration of biologics is highly desirable; however, incomplete bioavailability after s.c. administration remains a major challenge. In this work we investigated the effects of excipient dependent hyperosmolarity on lymphatic uptake and plasma exposure of rituximab as a model protein. Using Swiss Webster (SW) mice as the animal model, we compared the effects of NaCl, mannitol and O-phospho-L-serine (OPLS) on the plasma concentration of rituximab over 5 days after s.c. administration. An increase was observed in plasma concentrations in animals administered rituximab in hypertonic buffer solutions, compared with isotonic buffer. Bioavailability, as estimated by our pharmacokinetic model, increased from 29% in isotonic buffer to 54% in hypertonic buffer containing NaCl, to almost complete bioavailability in hypertonic buffers containing high dose OPLS or mannitol. This improvement in plasma exposure is due to the improved lymphatic trafficking as evident from the increase in the fraction of dose trafficked through the lymph nodes in the presence of hypertonic buffers. The fraction of the dose trafficked through the lymphatics, as estimated by the model, increased from 0.05% in isotonic buffer to 13% in hypertonic buffer containing NaCl to about 30% for hypertonic buffers containing high dose OPLS and mannitol. The data suggest that hypertonic solutions may be a viable option for improving s.c. bioavailability. Copyright © 2014 John Wiley & Sons, Ltd.

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

African Journals Online (AJOL)

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

SERDP and ESTCP Expert Panel Workshop on Research and Development Needs for Understanding and Assessing the Bioavailability of Contaminants in Soils and Sediments

Science.gov (United States)

2008-11-01

compartments contributing to fish tissue uptake. Develop tools to evaluate contaminant source apportionment into fish and higher trophic levels for use in... apportionment into risk assessments. 7.1.1.2 Improved Understanding of Metal Bioavailability in Sediments. The bioavailability of metals from...Bryan, G.W. and Langston, W.J., 1992. Bioavailability, Accumulation and Effects of Heavy Metals in Sediments with Special Reference to United

Bioavailability of cadmium from soy isolate

International Nuclear Information System (INIS)

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

1986-01-01

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

Gender differences on bioavailability of ofloxacin

International Nuclear Information System (INIS)

Hassan, Z.U.; Naseer, R.

2008-01-01

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

Dissolution and oral bioavailability enhancement of praziquantel by solid dispersions.

Science.gov (United States)

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

2018-06-01

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

Iron bioavailability of Lupinus rotundiflorus seeds and roots in low-iron-diet treated rats

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Elia Herminia VALDÉS MIRAMONTES

Full Text Available ABSTRACT Objective To evaluate iron bioavailability of roots and cooked seeds of Lupinus rotundiflorus for human consumption using a low-iron-diet rat model. Methods A hemoglobin depletion–repletion test was performed using rats. A standard diet containing 8mg kg-1 of iron was used. Three experimental diets were prepared based on the standard diet: 2.3g of root flour added to D1, 21.5g cooked seed flour added to D2, and 0.03g of ferrous sulfate added to D3 (control diet, adjusting iron concentration of the diets to 24mg kg-1. Hemoglobin regeneration efficiency was used to measure iron bioavailability. Results Hemoglobin regeneration efficiency showed values of 13.80+2.49%, 13.70+1.60% and 18.38+1.56 in D1, D2 and D3 respectively, and biological relative values of 72.8, 75.08, and 100.00% (.<0.05. Conclusion Roots and cooked seeds of Lupinus rotundiflorus showed potential iron bioavailability, despite being a vegetal source, which could also encourage the study of other species of lupin as a source of iron.

Iron Bioavailability Studies of the First Generation of Iron-Biofortified Beans Released in Rwanda.

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Glahn, Raymond; Tako, Elad; Hart, Jonathan; Haas, Jere; Lung'aho, Mercy; Beebe, Steve

2017-07-21

This paper represents a series of in vitro iron (Fe) bioavailability experiments, Fe content analysis and polyphenolic profile of the first generation of Fe biofortified beans ( Phaseolus vulgaris ) selected for human trials in Rwanda and released to farmers of that region. The objective of the present study was to demonstrate how the Caco-2 cell bioassay for Fe bioavailability can be utilized to assess the nutritional quality of Fe in such varieties and how they may interact with diets and meal plans of experimental studies. Furthermore, experiments were also conducted to directly compare this in vitro approach with specific human absorption studies of these Fe biofortified beans. The results show that other foods consumed with beans, such as rice, can negatively affect Fe bioavailability whereas potato may enhance the Fe absorption when consumed with beans. The results also suggest that the extrinsic labelling approach to measuring human Fe absorption can be flawed and thus provide misleading information. Overall, the results provide evidence that the Caco-2 cell bioassay represents an effective approach to evaluate the nutritional quality of Fe-biofortified beans, both separate from and within a targeted diet or meal plan.

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

OpenAIRE

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

2018-01-01

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

Development of a facile and sensitive HPLC-FLD method via fluorescence labeling for triterpenic acid bioavailability investigation.

Science.gov (United States)

You, Jinmao; Wu, Di; Zhao, Mei; Li, Guoliang; Gong, Peiwei; Wu, Yueyue; Guo, Yu; Chen, Guang; Zhao, Xianen; Sun, Zhiwei; Xia, Lian; Wu, Yongning

2017-06-01

Triterpenic acids are widely distributed in many fruits and are known for their medicinal benefits. The study of bioavailability has been an important task for a better understanding of the triterpenic acids. Although many methods based on fluorescence labeling for triterpenic acid determination have been established, these reported methods needed anhydrous conditions, which are not suitable for the convenient study of triterpenic acid bioavailability. Inspired by that, a versatile method, which overcomes the difficulty of the reported methods, has been first developed in this study. The novel method using 2-[12-benzo[b]acridin-5- (12H)-yl]-acetohydrazide (BAAH) as the fluorescence labeling reagent coupled with high-performance liquid chromatography with fluorescence detection was first developed for the study of triterpenic acid bioavailability. Furthermore, the labeling conditions have been optimized in order to achieve the best fluorescence labeling yield. Under the optimal conditions, the quantitative linear range of analytes was 2-1000 ng mL -1 , and the correlation coefficients were >0.9998. The detection limits for all triterpenic acid derivatives were achieved within the range of 0.28-0.29 ng mL -1 . The proposed method was successfully applied to the study of triterpenic acid bioavailability with excellent applicability and good reproducibility. Copyright © 2016 John Wiley & Sons, Ltd.

In-situ Mass Distribution Quotient (iMDQ) - A New Factor to Compare Bioavailability of Pesticides in Soils?

Science.gov (United States)

Schroll, R.; Folberth, C.; Scherb, H.; Suhadolc, M.; Munch, J. C.

2009-04-01

Aim of this work was the development of a new non-biological factor to determine microbial in-situ bioavailability of chemicals in soils. Pesticide residues were extracted from ten highly different agricultural soils that had been incubated with the 14C-herbicide isoproturon (IPU) under comparable soil conditions (water tension - 15 kPa; soil density 1.3 g cm 3). Two different pesticide extraction approaches were compared: (i) 14C-Pesticide residues were measured in the pore water (PW) which was extracted from soil by centrifugation; (ii) 14C-Pesticide residues were extracted from soil samples with an excess of water (EEW). We introduce the pesticide's in-situ mass distribution quotient (iMDQ) as a measure for pesticide bioavailability, which is calculated as a quotient of adsorbed and dissolved chemical amounts for both approaches (iMDQPW, iMDQEEW). Pesticide mineralization in soils served as a reference for real microbial availability. A highly significant correlation between iMDQPW and mineralization showed that pore water extraction is adequate to assess IPU bioavailability. In contrast, no correlation exists between IPU mineralization and its extractability from soil with an excess of water. Therefore, it can be concluded that soil equilibration at comparable conditions and subsequent pore water extraction is vital for a isoproturon bioavailability ranking of soils.

Polymeric Micelles, a Promising Drug Delivery System to Enhance Bioavailability of Poorly Water-Soluble Drugs

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Wei Xu

2013-01-01

Full Text Available Oral administration is the most commonly used and readily accepted form of drug delivery; however, it is find that many drugs are difficult to attain enough bioavailability when administered via this route. Polymeric micelles (PMs can overcome some limitations of the oral delivery acting as carriers able to enhance drug absorption, by providing (1 protection of the loaded drug from the harsh environment of the GI tract, (2 release of the drug in a controlled manner at target sites, (3 prolongation of the residence time in the gut by mucoadhesion, and (4 inhibition of efflux pumps to improve the drug accumulation. To explain the mechanisms for enhancement of oral bioavailability, we discussed the special stability of PMs, the controlled release properties of pH-sensitive PMs, the prolongation of residence time with mucoadhesive PMs, and the P-gp inhibitors commonly used in PMs, respectively. The primary purpose of this paper is to illustrate the potential of PMs for delivery of poorly water-soluble drugs with bioavailability being well maintained.

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

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Ke, Zhongcheng; Hou, Xuefeng; Jia, Xiao-Bin

2016-01-01

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. 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. 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. SNEDDS could be a potential candidate for an oral dosage form of cyclovirobuxine D with improved bioavailability.

Effect of antacids in didanosine tablet on bioavailability of isoniazid.

OpenAIRE

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

1994-01-01

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

Effect of antacids in didanosine tablet on bioavailability of isoniazid.

Science.gov (United States)

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

1994-04-01

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

Influence of bacteria on Pb and Zn speciation, mobility and bioavailability in soil: A laboratory study

International Nuclear Information System (INIS)

Wu, S.C.; Luo, Y.M.; Cheung, K.C.; Wong, M.H.

2006-01-01

A soil column experiment was carried out to investigate the effects of inoculation of bacteria on metal bioavailability, mobility and potential leachability through single chemical extraction, consequential extraction and in situ soil solution extraction technologies. Results showed that bacteria inoculated, including Azotobacter chroococcum, Bacillus megaterium and Bacillus mucilaginosus, may pose both positive and negative impacts on bioavailability and mobility of heavy metals in soil, depending on the chemical nature of the metals. The activities of bacteria led to an increase of water dissolved organic carbon (DOC) concentration and a decrease of pH value, which enhanced metal mobility and bioavailability (e.g. an increase of water-soluble and HOAc-soluble Zn). On the other hand, bacteria could immobilize metals (e.g. a great reduction of water-soluble Pb) due to the adsorption by bacterial cell walls and possible sedimentation reactions with phosphate or other anions produced through bacterial metabolism. - Influence of bacterial activities on heavy metal is two-edged

Soil sterilization affects aging-related sequestration and bioavailability of p,p'-DDE and anthracene to earthworms

International Nuclear Information System (INIS)

Slizovskiy, Ilya B.; Kelsey, Jason W.

2010-01-01

Laboratory experiments investigated the effects of soil sterilization and compound aging on the bioaccumulation of spiked p,p'-DDE and anthracene by Eisenia fetida and Lumbricus terrestris. Declines in bioavailability occurred as pollutant residence time in both sterile and non-sterile soils increased from 3 to 203 d. Accumulation was generally higher in sterile soils during initial periods of aging (from 3-103 d). By 203 d, however, bioavailability of the compounds was unaffected by sterilization. Gamma irradiation and autoclaving may have altered bioavailability by inducing changes in the chemistry of soil organic matter (SOM). The results support a dual-mode partitioning sorption model in which the SOM components associated with short-term sorption (the 'soft' or 'rubbery' phases) are more affected than are the components associated with long-term sorption (the 'glassy' or microcrystalline phases). Risk assessments based on data from experiments in which sterile soil was used could overestimate exposure and bioaccumulation of pollutants. - Soil sterilization affects aging-related sequestration of organic contaminants.

Quantifying the effect of sorption and bioavailability of hydrophobic organic contaminants

International Nuclear Information System (INIS)

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

1994-01-01

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

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 CapryolTM90, 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

Animal bioavailability of defined xenobiotic lignin metabolites

International Nuclear Information System (INIS)

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

1990-01-01

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

Enhanced oral bioavailability and anticancer efficacy of fisetin by encapsulating as inclusion complex with HPβCD in polymeric nanoparticles.

Science.gov (United States)

Kadari, Amrita; Gudem, Sagarika; Kulhari, Hitesh; Bhandi, Murali Mohan; Borkar, Roshan M; Kolapalli, Venkata Ramana Murthy; Sistla, Ramakrishna

2017-11-01

Fisetin (FST), a potent anticancer phytoconstituent, exhibits poor aqueous solubility and hence poor bioavailability. The aim of the present study is to improve the oral bioavailability of FST by encapsulating into PLGA NPs (poly-lactide-co-glycolic acid nanoparticles) as a complex of HPβCD (hydroxyl propyl beta cyclodextrin) and to assess its anti-cancer activity against breast cancer cells. FST-HPβCD inclusion complex (FHIC) was prepared and the supramolecular complex formation was characterized by FTIR, DSC, PXRD and 1 H NMR. FHIC encapsulated PLGA nanoparticles (FHIC-PNP) were prepared and were studied for in vitro anticancer activity, cellular uptake, apoptosis and reactive oxygen species generation in MCF-7 human breast cancer cells. Comparative bioavailability of FST was determined after oral administration in C57BL6 mice as pure FST and FHIC-PNP. The results revealed that FHIC-PNP not only enhanced the anti-cancer activity and apoptosis of FST against MCF-7 cells but also improved its oral bioavailability, as demonstrated by increased peak plasma concentration and total drug absorbed.

Copper availability and bioavailability are controlled by rhizosphere pH in rape grown in an acidic Cu-contaminated soil

Energy Technology Data Exchange (ETDEWEB)

Chaignon, Valerie; Quesnoit, Marie [INRA, UMR 1222 Eco and Sols Ecologie fonctionnelle and Biogeochimie des Sols (INRA-IRD-SupAgro), Place Viala, F-34060 Montpellier (France); Hinsinger, Philippe, E-mail: philippe.hinsinger@supagro.inra.f [INRA, UMR 1222 Eco and Sols Ecologie fonctionnelle and Biogeochimie des Sols (INRA-IRD-SupAgro), Place Viala, F-34060 Montpellier (France)

2009-12-15

We evaluated how root-induced changes in rhizosphere pH varied and interacted with Cu availability and bioavailability in an acidic soil. Rape was grown on a Cu-contaminated acidic soil, which had been limed at 10 rates. Soil Cu bioavailability was not influenced by liming. However, liming significantly decreased CaCl{sub 2}-extracted Cu for pH between 3.7 and 5.1. Little effect was found for pH above 5.1. For soil pH < 4.4, CaCl{sub 2}-Cu contents were smaller in rhizosphere than uncropped soil. Rhizosphere alkalisation occurred at pH < 4.8, while acidification occurred at greater pH. This explained the changes of CaCl{sub 2}-Cu in the rhizosphere at low pH and the absence of pH dependency of Cu bioavailability to rape. In addition, apoplastic Cu in roots increased with increasing soil pH, most probably as a result of increased dissociation and affinity of cell wall compounds for Cu. - Root-induced increase in pH reduces Cu availability in the rhizosphere and Cu bioavailability to rape.

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

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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

Curcumin-loaded self-nanomicellizing solid dispersion system: part I: development, optimization, characterization, and oral bioavailability.

Science.gov (United States)

Parikh, Ankit; Kathawala, Krishna; Song, Yunmei; Zhou, Xin-Fu; Garg, Sanjay

2018-05-29

Curcumin (CUR) is considered as one of the most bioactive molecules ever discovered from nature due to its proven anti-inflammatory and antioxidant in both preclinical and clinical studies. Despite its proven safety and efficacy, the clinical translation of CUR into a useful therapeutic agent is still limited due to its poor oral bioavailability. To overcome its limitation and enhance oral bioavailability by improving its aqueous solubility, stability, and intestinal permeability, a novel CUR formulation (NCF) was developed using the self-nanomicellizing solid dispersion strategy. From the initial screening of polymers for their potential to improve the solubility and stability, Soluplus (SOL) was selected. The optimized NCF demonstrated over 20,000-fold improvement in aqueous solubility as a result of amorphization, hydrogen bonding interaction, and micellization determined using differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance, dynamic light scattering, and transmission electron microscopy. Moreover, the greater stabilizing effect in alkaline pH and light was observed. Furthermore, significant enhancement of dissolution and permeability of CUR across everted sacs of rat small intestine were noticed. Pharmacokinetic studies demonstrated that the oral bioavailability of CUR was increased 117 and 17-fold in case of NCF and physical mixture of CUR and SOL compared to CUR suspension. These results suggest NCF identified as a promising new approach for repositioning of CUR for pharmaceutical application by enhancing the oral bioavailability of CUR. The findings herein stimulate further in vivo evaluations and clinical tests of NCF.

Bioavailability and pharmacokinetics of oral and injectable formulations of methadone after intravenous, oral, and intragastric administration in horses.

Science.gov (United States)

Linardi, Renata L; Stokes, Ashley M; Keowen, Michael L; Barker, Steven A; Hosgood, Giselle L; Short, Charles R

2012-02-01

To characterize the bioavailability and pharmacokinetics of oral and injectable formulations of methadone after IV, oral, and intragastric administration in horses. 6 healthy adult horses. Horses received single doses (each 0.15 mg/kg) of an oral formulation of methadone hydrochloride orally or intragastrically or an injectable formulation of the drug orally, intragastrically, or IV (5 experimental treatments/horse; 2-week washout period between each experimental treatment). A blood sample was collected from each horse before and at predetermined time points over a 360-minute period after each administration of the drug to determine serum drug concentration by use of gas chromatography-mass spectrometry analysis and to estimate pharmacokinetic parameters by use of a noncompartmental model. Horses were monitored for adverse effects. In treated horses, serum methadone concentrations were equivalent to or higher than the effective concentration range reported for humans, without induction of adverse effects. Oral pharmacokinetics in horses included a short half-life (approx 1 hour), high total body clearance corrected for bioavailability (5 to 8 mL/min/kg), and small apparent volume of distribution corrected for bioavailability (0.6 to 0.9 L/kg). The bioavailability of methadone administered orally was approximately 3 times that associated with intragastric administration. Absorption of methadone in the small intestine in horses appeared to be limited owing to the low bioavailability after intragastric administration. Better understanding of drug disposition, including absorption, could lead to a more appropriate choice of administration route that would enhance analgesia and minimize adverse effects in horses.

MR measures of renal perfusion, oxygen bioavailability and total renal blood flow in a porcine model: noninvasive regional assessment of renal function.

Science.gov (United States)

Wentland, Andrew L; Artz, Nathan S; Fain, Sean B; Grist, Thomas M; Djamali, Arjang; Sadowski, Elizabeth A

2012-01-01

Magnetic resonance imaging (MRI) may be a useful adjunct to current methods of evaluating renal function. MRI is a noninvasive imaging modality that has the ability to evaluate the kidneys regionally, which is lacking in current clinical methods. Other investigators have evaluated renal function with MRI-based measurements, such as with techniques to measure cortical and medullary perfusion, oxygen bioavailability and total renal blood flow (TRBF). However, use of all three techniques simultaneously, and therefore the relationships between these MRI-derived functional parameters, have not been reported previously. To evaluate the ability of these MRI techniques to track changes in renal function, we scanned 11 swine during a state of hyperperfusion with acetylcholine and a saline bolus and subsequently scanned during a state of hypoperfusion with the prolonged use of isoflurane anesthesia. For each time point, measurements of perfusion, oxygen bioavailability and TRBF were acquired. Measurements of perfusion and oxygen bioavailability were compared with measurements of TRBF for all swine across all time points. Cortical perfusion, cortical oxygen bioavailability, medullary oxygen bioavailability and TRBF significantly increased with the acetylcholine challenge. Cortical perfusion, medullary perfusion, cortical oxygen bioavailability and TRBF significantly decreased during isoflurane anesthesia. Cortical perfusion (Spearman's correlation coefficient = 0.68; P renal function. Maintenance of the medullary oxygen bioavailability in low blood flow states may reflect the autoregulation particular to this region of the kidney. The ability to non-invasively measure all three parameters of kidney function in a single MRI examination and to evaluate the relationships between these functional parameters is potentially useful for evaluating the state of the human kidneys in situ in future studies.

Utilizing thin-film solid-phase extraction to assess the effect of organic carbon amendments on the bioavailability of DDT and dieldrin to earthworms

International Nuclear Information System (INIS)

Andrade, Natasha A.; Centofanti, Tiziana; McConnell, Laura L.; Hapeman, Cathleen J.; Torrents, Alba; Nguyen, Anh; Beyer, W. Nelson; Chaney, Rufus L.; Novak, Jeffrey M.; Anderson, Marya O.; Cantrell, Keri B.

2014-01-01

Improved approaches are needed to assess bioavailability of hydrophobic organic compounds in contaminated soils. Performance of thin-film solid-phase extraction (TF-SPE) using vials coated with ethylene vinyl acetate was compared to earthworm bioassay (Lumbricus terrestris). A DDT and dieldrin contaminated soil was amended with four organic carbon materials to assess the change in bioavailability. Addition of organic carbon significantly lowered bioavailability for all compounds except for 4,4′-DDT. Equilibrium concentrations of compounds in the polymer were correlated with uptake by earthworms after 48d exposure (R 2 = 0.97; p 40yr of aging. Results show that TF-SPE can be useful in examining potential risks associated with contaminated soils and to test effectiveness of remediation efforts. -- Highlights: • Bioavailability of pesticides in soil were assessed using TF-SPE and earthworms. • Soil from a historical orchard was used to examine aged residues of dieldrin and DDT. • TF-SPE results were strongly correlated with earthworm bioaccumulation factors. • Ethylene vinyl acetate polymer has sorptive capacity similar to earthworm lipid. • TF-SPE useful to estimate bioavailability of hydrophobic organic pesticides in soil. -- Capsule A thin-film polymer sampler proved to be efficient in estimating the differences in bioavailability to earthworms in a soil treated with organic amendments

Seed coat removal improves Fe bioavailability in cooked lentils: studies using an in vitro digestion/Caco-2 cell culture model

Science.gov (United States)

This study examined the range of Fe concentration and relative Fe bioavailability of 24 varieties of cooked lentils, as well as the impact of seed coat removal on lentil Fe nutritional quality. Relative Fe bioavailability was assessed by the in vitro/Caco-2 cell culture method. While Fe concentrat...

Analyzing the capacity of the Daphnia magna and Pseudokirchneriella subcapitata bioavailability models to predict chronic zinc toxicity at high pH and low calcium concentrations and formulation of a generalized bioavailability model for D. magna.

Science.gov (United States)

Van Regenmortel, Tina; Berteloot, Olivier; Janssen, Colin R; De Schamphelaere, Karel A C

2017-10-01

Risk assessment in the European Union implements Zn bioavailability models to derive predicted-no-effect concentrations for Zn. These models are validated within certain boundaries (i.e., pH ≤ 8 and Ca concentrations ≥ 5mg/L), but a substantial fraction of the European surface waters falls outside these boundaries. Therefore, we evaluated whether the chronic Zn biotic ligand model (BLM) for Daphnia magna and the chronic bioavailability model for Pseudokirchneriella subcapitata could be extrapolated to pH > 8 and Ca concentrations model can accurately predict Zn toxicity for Ca concentrations down to 0.8 mg/L and pH values up to 8.5. Because the chronic Zn BLM for D. magna could not be extrapolated beyond its validity boundaries for pH, a generalized bioavailability model (gBAM) was developed. Of 4 gBAMs developed, we recommend the use of gBAM-D, which combines a log-linear relation between the 21-d median effective concentrations (expressed as free Zn 2+ ion activity) and pH, with more conventional BLM-type competition constants for Na, Ca, and Mg. This model is a first step in further improving the accuracy of chronic toxicity predictions of Zn as a function of water chemistry, which can decrease the uncertainty in implementing the bioavailability-based predicted-no-effect concentration in the risk assessment of high-pH and low-Ca concentration regions in Europe. Environ Toxicol Chem 2017;36:2781-2798. © 2017 SETAC. © 2017 SETAC.

Evaluation of soil metal bioavailability estimates using two plant species (L. perenne and T. aestivum) grown in a range of agricultural soils treated with biosolids and metal salts

International Nuclear Information System (INIS)

Black, Amanda; McLaren, Ronald G.; Reichman, Suzanne M.; Speir, Thomas W.; Condron, Leo M.

2011-01-01

Few studies have quantified the accuracy of soil metal bioavailability assays using large datasets. A meta-analysis from experiments spanning 6 months to 13 years on 12 soil types, compared bioavailability estimate efficiencies for wheat and ryegrass. Treatments included biosolids ± metals, comparing total metal, Ca(NO 3 ) 2 , EDTA, soil solution, DGT and free ion activity. The best correlations between soil metal bioavailability and shoot concentrations were for Ni using Ca(NO 3 ) 2 (r 2 = 0.72) which also provided the best estimate of Zn bioavailability (r 2 = 0.64). DGT provided the best estimate of Cd bioavailability, accounting for 49% of shoot Cd concentrations. There was no reliable descriptor of Cu bioavailability, with less than 35% of shoot Cu concentrations defined. Thus interpretation of data obtained from many soil metal bioavailability assays is unreliable and probably flawed, and there is little justification to look beyond Ca(NO 3 ) 2 for Ni and Zn, and DGT for Cd. - Highlights: → A meta-analysis evaluated the efficacy of soil metal bioavailability assays. → DGT could explain 49% of shoot Cd concentration. → There is little justification to look beyond Ca(NO 3 ) 2 for Ni and Zn. - A meta-analysis of soil metal bioavailability estimates for 12 soil types concluded that there is little justification to look beyond Ca(NO 3 ) 2 for Ni and Zn, and DGT for Cd.

Enhanced oral bioavailability of felodipine by novel solid self-microemulsifying tablets.

Science.gov (United States)

Jing, Boyu; Wang, Zhiyuan; Yang, Rui; Zheng, Xia; Zhao, Jia; Tang, Si; He, Zhonggui

2016-01-01

The novel self-microemulsifying (SME) tablets were developed to enhance the oral bioavailability of a poor water-soluble drug felodipine (FDP). Firstly, FDP was dissolved in the optimized liquid self-microemusifying drug delivery systems (SMEDDS) containing Miglyol® 812, Cremophor® RH 40, Tween 80 and Transcutol® P, and the mixture was solidified with porous silicon dioxide and crospovidone as adsorbents. Then after combining the solidified powders with other excipients, the solid SME tablets were prepared by wet granulation-compression method. The prepared tablets possessed satisfactory characterization; the droplet size of the SME tablets following self-emulsification in water was nearly equivalent to the liquid SMEDDS (68.4 ± 14.0 and 64.4 ± 12.0 nm); differential scanning calorimetry (DSC) and powder X-ray diffractometry (PXRD) analysis demonstrated that FDP in SME tablets had undergone a polymorphism transition from a crystal form to an amorphous state, which was further confirmed by transmission electron microscopy (TEM). A similar dissolution performance of SME tablets and liquid SMEDDS was also obtained under the sink condition (85% within 10 min), both significantly higher than commercial tablets. The oral bioavailability was evaluated for the SME tablets, liquid SMEDDS and commercial conventional tablets in the fasted beagle dogs. The AUC of FDP from the SME tablets was about 2-fold greater than that of conventional tablets, but no significant difference was found when compared with the liquid SMEDDS. Accordingly, these preliminary results suggest that this formulation approach offers a useful large-scale producing method to prepare the solid SME tablets from the liquid SMEDDS for oral bioavailability equivalent enhancement of poorly soluble FDP.

Assessing the bioavailability of organic contaminants using a novel bioluminescent biosensor

International Nuclear Information System (INIS)

Keane, A.; Phoenix, P.; Lau, P.C.K.; Ghoshal, S.

2002-01-01

The limited rate and extent of biodegradation in contaminated soils is often attributed to a lack of bioavailability of hydrophobic organic compounds. To date, the majority of studies aimed at assessing bioavailability and modes of bacterial uptake have relied upon quantification of microbial degradation rates in comparison to rates of dissolution or desorption in corresponding abiotic systems. Several studies have indicated the possibility of a direct uptake mechanism for sorbed or separate phase compounds. However, there is a lack of direct evidence to support these claims. To address the need for a direct measurement technique for microbial bioavailability, we have constructed a whole-cell bioluminescent biosensor, Pseudomonas putida F1G4 (PpF1G4), by fusing lux genes that encode for bioluminescence to the solvent efflux pump (sep) promoter element in PpF1G4, which is induced by the presence of target organic compounds. When the biosensor microorganism is exposed to an inducing compound, the bioluminescence system is activated and the cell produces an intensity of visible light (λ = 495 nm) that is directly related to the level of exposure to the contaminant. Batch experiments were carried out to assess whether the biosensor is able to sense the presence of toluene, a representative target compound, contained in a NAPL. Preliminary results show that while PpF1G4 responds to toluene in the aqueous phase, the biosensor does not appear to emit a significant bioluminescence signal in response to the toluene present in the NAPL. Ongoing research is focusing on optimizing the experimental procedure to fully explore this issue. (author)

Influence of dispersants on petroleum bioavailability in a marine food chain

International Nuclear Information System (INIS)

Wolfe, M.; Tjeerdema, R.

1995-01-01

When crude oil is accidentally released into the ocean it threatens many levels of marine life. Intervention, in the form of chemical dispersing agents, may alter the normal behavior of petroleum hydrocarbons (PH) by increasing their functional water solubility and the extent of their exposure to sub-surface marine organisms. Further, the dispersing agent may modify bioavailability as a result of altered interactions between dispersed PH droplets and organismal cell membranes, To date, little information exists on the sub-lethal effects of dispersants and factors modifying their role in the bioavailability and disposition of PH in marine food chains. The objective of the current research was to determine the impact of dispersing agents on PH bioavailability to primary levels of a marine food chain. Uptake, bioaccumulation, deputation, and metabolic transformation of a model PH, 14 C-naphthalene, were measured and compared for dispersed Prudhoe Bay Crude Oil (PBCO) vs. undispersed preparations of the water-accommodated fractions (WAF) of PBCO at two salinities (22 and 34 ppt) employing Isochrysis galbana, a primary producer, and Brachionus plicatilis, a primary consumer. Fractionation and identification of metabolites was done by HPLC co-chromatography with analytical standards, and quantitation was done by liquid scintillation counting. GC-FID characterization of WAF and dispersed oil preparations shows higher concentrations of petroleum hydrocarbons and a greater number of individual constituents in the dispersed oil preparations. However, short term (eight hour) and long term (two week) static exposure studies indicate the uptake of 14 C-naphthalene from WAF preparations is inhibited by up to 50% from dispersed oil preparations. Results of comparative static and flow-through chamber exposure studies will be presented

Influence of dispersants on petroleum bioavailability in a marine food chain

Energy Technology Data Exchange (ETDEWEB)

Wolfe, M.; Tjeerdema, R. [Univ. of California, Santa Cruz, CA (United States). Dept. of Chemistry and Biochemistry; Sowby, M. [California Dept. of Fish and Game, Sacramento, CA (United States)

1995-12-31

When crude oil is accidentally released into the ocean it threatens many levels of marine life. Intervention, in the form of chemical dispersing agents, may alter the normal behavior of petroleum hydrocarbons (PH) by increasing their functional water solubility and the extent of their exposure to sub-surface marine organisms. Further, the dispersing agent may modify bioavailability as a result of altered interactions between dispersed PH droplets and organismal cell membranes, To date, little information exists on the sub-lethal effects of dispersants and factors modifying their role in the bioavailability and disposition of PH in marine food chains. The objective of the current research was to determine the impact of dispersing agents on PH bioavailability to primary levels of a marine food chain. Uptake, bioaccumulation, deputation, and metabolic transformation of a model PH, {sup 14}C-naphthalene, were measured and compared for dispersed Prudhoe Bay Crude Oil (PBCO) vs. undispersed preparations of the water-accommodated fractions (WAF) of PBCO at two salinities (22 and 34 ppt) employing Isochrysis galbana, a primary producer, and Brachionus plicatilis, a primary consumer. Fractionation and identification of metabolites was done by HPLC co-chromatography with analytical standards, and quantitation was done by liquid scintillation counting. GC-FID characterization of WAF and dispersed oil preparations shows higher concentrations of petroleum hydrocarbons and a greater number of individual constituents in the dispersed oil preparations. However, short term (eight hour) and long term (two week) static exposure studies indicate the uptake of{sup 14}C-naphthalene from WAF preparations is inhibited by up to 50% from dispersed oil preparations. Results of comparative static and flow-through chamber exposure studies will be presented.

Requirement-specific use of trace element biogas additives under consideration of the bioavailability; Bedarfsgerechter Einsatz von Spurenelement-Biogasadditiven unter Beruecksichtigung der Bioverfuegbarkeit

Energy Technology Data Exchange (ETDEWEB)

Feher, Adam; Fritz, Thomas; Loewen, Achim; Nelles, Michael [HAWK Hochschule fuer Angewandte Wissenschaft und Kunst Hildesheim/Holzminden/Goettingen, Goettingen (Germany). Fachgebiet Nachhaltige Energie- und Umwelttechnik (NEUTec)

2013-10-01

A highly efficient utilisation of substrates and operational stability at the same time is essential for the efficiency of a biogas plant. The research project SequEx of HAWK and /SF GmbH investigates the increase of efficiency of biogas plants by targeted use of trace elements taking into account bio-availability. Based on sequential extraction diagrams a method for the determination of bio-availability of macro- and micro-nutrients is developed. Within this context, different trace element compounds are analysed during the fermentation process on their share of bioavailable micro-nutrients as well as their effect on the biological activity of microorganisms. The actual knowledge gap between common practice of nutrients' supply and real impact shall be closed by the knowledge base enhancement of the bio-availability of nutrients. (orig.)

Enhanced oral bioavailability of fenofibrate using polymeric nanoparticulated systems: physicochemical characterization and in vivo investigation

Directory of Open Access Journals (Sweden)

Yousaf AM

2015-03-01

Full Text Available Abid Mehmood Yousaf,1 Dong Wuk Kim,1 Yu-Kyoung Oh,2 Chul Soon Yong,3 Jong Oh Kim,3 Han-Gon Choi11College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, 2College of Pharmacy, Seoul National University, Seoul, 3College of Pharmacy, Yeungnam University, Gyongsan, South KoreaBackground: The intention of this research was to prepare and compare various solubility-enhancing nanoparticulated systems in order to select a nanoparticulated formulation with the most improved oral bioavailability of poorly water-soluble fenofibrate.Methods: The most appropriate excipients for different nanoparticulated preparations were selected by determining the drug solubility in 1% (w/v aqueous solutions of each carrier. The polyvinylpyrrolidone (PVP nanospheres, hydroxypropyl-β-cyclodextrin (HP-β-CD nanocorpuscles, and gelatin nanocapsules were formulated as fenofibrate/PVP/sodium lauryl sulfate (SLS, fenofibrate/HP-β-CD, and fenofibrate/gelatin at the optimized weight ratios of 2.5:4.5:1, 1:4, and 1:8, respectively. The three solid-state products were achieved using the solvent-evaporation method through the spray-drying technique. The physicochemical characterization of these nanoparticles was accomplished by powder X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Their physicochemical properties, aqueous solubility, dissolution rate, and pharmacokinetics in rats were investigated in comparison with the drug powder.Results: Among the tested carriers, PVP, HP-β-CD, gelatin, and SLS showed better solubility and were selected as the most appropriate constituents for various nanoparticulated systems. All of the formulations significantly improved the aqueous solubility, dissolution rate, and oral bioavailability of fenofibrate compared to the drug powder. The drug was present in the amorphous form in HP-β-CD nanocorpuscles; however, in

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

NARCIS (Netherlands)

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

2002-01-01

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

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

Directory of Open Access Journals (Sweden)

Eva Brglez Mojzer

2016-07-01

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

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.

Significance of excipients to enhance the bioavailability of poorly water-soluble drugs in oral solid dosage forms: A Review

Science.gov (United States)

Vadlamudi, Manoj Kumar; Dhanaraj, Sangeetha

2017-11-01

Nowadays most of the drug substances are coming into the innovation pipeline with poor water solubility. Here, the influence of excipients will play a significant role to improve the dissolution of poorly aqueous soluble compounds. The drug substance needs to be dissolved in gastric fluids to get the better absorption and bioavailability of an orally administered drug. Dissolution is the rate-controlling stage for drugs which controls the rate and degree of absorption. Usually, poorly soluble oral administrated drugs show a slower dissolution rate, inconsistent and incomplete absorption which can lead to lower bioavailability. The low aqueous solubility of BCS class II and IV drugs is a major challenge in the drug development and delivery process. Several technologies have been used in an attempt to progress the bioavailability of poorly water-soluble drug compounds which include solid dispersions, lipid-based formulations, micronization, solvent evaporation, co-precipitation, ordered mixing, liquid-solid compacts, solvent deposition inclusion complexation, and steam aided granulation. In fact, most of the technologies require excipient as a carrier which plays a significant role in improving the bioavailability using Hypromellose acetate succinate, Cyclodextrin, Povidone, Copovidone, Hydroxypropyl cellulose, Hydroxypropyl methylcellulose, Crospovidone, Starch, Dimethylacetamide, Polyethylene glycol, Sodium lauryl sulfate, Polysorbate, Poloxamer. Mesoporous silica and so on. This review deliberates about the excipients significance on bioavailability enhancement of drug products in a single platform along with pragmatically proved applications so that user can able to select the right excipients as per the molecule.

Addition of contaminant bioavailability and species susceptibility to a sediment toxicity assessment: Application in an urban stream in China

International Nuclear Information System (INIS)

Li, Huizhen; Sun, Baoquan; Chen, Xin; Lydy, Michael J.; You, Jing

2013-01-01

Sediments collected from an urban creek in China exhibited high acute toxicity to Hyalella azteca with 81.3% of sediments being toxic. A toxic unit (TU) estimation demonstrated that the pyrethroid, cypermethrin, was the major contributor to toxicity. The traditional TU approach, however, overestimated the toxicity. Reduced bioavailability of sediment-associated cypermethrin due to sequestration explained the overestimation. Additionally, antagonism among multiple contaminants and species susceptibility to various contaminants also contributed to the unexpectedly low toxicity to H. azteca. Bioavailable TUs derived from the bioavailability-based approaches, Tenax extraction and matrix-solid phase microextraction (matrix-SPME), showed better correlations with the noted toxicity compared to traditional TUs. As the first successful attempt to use matrix-SPME for estimating toxicity caused by emerging insecticides in field sediment, the present study found freely dissolved cypermethrin concentrations significantly improved the prediction of sediment toxicity to H. azteca compared to organic carbon normalized and Tenax extractable concentrations. Highlights: •Over 80% sediments from an urban stream in China were acutely toxic to H. azteca. •Toxic unit analysis showed cypermethrin was the major contributor to toxicity. •The traditional toxic unit approach overestimated sediment toxicity. •Reduced bioavailability was the reason for overestimating sediment toxicity. •Freely dissolved cypermethrin concentrations greatly improved toxicity prediction. -- Field sediment toxicity caused by current-use pesticides could be more accurately evaluated by incorporating bioavailability measurements into the toxic unit analysis

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

Science.gov (United States)

Della Lucia, Ceres Mattos; Santos, Laura Luiza Menezes; Rodrigues, Kellen Cristina da Cruz; Rodrigues, Vivian Cristina da Cruz; Martino, Hércia Stampini Duarte; Pinheiro Sant’Ana, Helena Maria

2014-01-01

The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice®) is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn) in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3)), supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca) and magnesium (Mg) in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p 0.05) for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification. PMID:24932657

Preparation and evaluation of self-microemulsions for improved bioavailability of ginsenoside-Rh1 and Rh2.

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Yang, Feifei; Zhou, Jing; Hu, Xiao; Yu, Stephanie Kyoungchun; Liu, Chunyu; Pan, Ruile; Chang, Qi; Liu, Xinmin; Liao, Yonghong

2017-10-01

Due to intestinal cytochrome P450 (CYP450)-mediated metabolism and P-glycoprotein (P-gp) efflux, poor oral bioavailability hinders ginsenoside-Rh1 (Rh1) and ginsenoside-Rh2 (Rh2) from clinical application. In this study, Rh1 and Rh2 were incorporated into two self-microemulsions (SME-1 and SME-2) to improve oral bioavailability. SME-1 contained both CYP450 and P-gp inhibitory excipients while SME-2 only consisted of P-gp inhibitory excipients. Results for release, cellular uptake, transport, and lymph node distribution demonstrated no significant difference between either self-microemulsions in vivo, but were elevated significantly in comparison to the free drug. The pharmaceutical profiles in vivo showed that the bioavailability of Rh1 in SME-1 (33.25%) was significantly higher than that in either SME-2 (21.28%) or free drug (12.92%). There was no significant difference in bioavailability for Rh2 between SME-1 (48.69%) or SME-2 (41.73%), although they both had remarkable increase in comparison to free drug (15.02%). We confirmed that SME containing CYP450 and P-gp inhibitory excipient could distinctively improve the oral availabilities of Rh1 compared to free drug or SME containing P-gp inhibitory excipient. No notable increase was observed between either SME for Rh2, suggesting that Rh2 undergoes P-gp-mediated efflux, but may not undergo distinct CYP450-mediated metabolism.

Improved oral bioavailability and therapeutic efficacy of dabigatran etexilate via Soluplus-TPGS binary mixed micelles system.

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Hu, Mei; Zhang, Jinjie; Ding, Rui; Fu, Yao; Gong, Tao; Zhang, Zhirong

2017-04-01

The clinical use of dabigatran etexilate (DABE) is limited by its poor absorption and relatively low bioavailability. Our study aimed to explore the potential of a mixed micelle system composed of Soluplus ® and D-alpha tocopheryl polyethylene glycol 1000 succinate (TPGS) to improve the oral absorption and bioavailability of DBAE. DBAE was first encapsulated into Soluplus/TPGS mixed micelles by a simple thin film hydration method. The DBAE loaded micelles displayed an average size distribution of around 83.13 nm. The cellular uptake of DBAE loaded micelles in Caco-2 cell monolayer was significantly enhanced by 2-2.6 fold over time as compared with DBAE suspension. Both lipid raft/caveolae and macropinocytosis-mediated the cell uptake of DBAE loaded micelles through P-glycoprotein (P-gp)-independent pathway. Compared with the DBAE suspension, the intestinal absorption of DBAE from DBAE mixed micelles in rats was significantly improved by 8 and 5-fold in ileum at 2 h and 4 h, respectively. Moreover, DBAE mixed micelles were absorbed into systemic circulation via both portal vein and lymphatic pathway. The oral bioavailability of DBAE mixed micelles in rats was 3.37 fold higher than that of DBAE suspension. DBAE mixed micelles exhibited a comparable anti-thrombolytic activity with a thrombosis inhibition rate of 63.18% compared with DBAE suspension in vivo. Thus, our study provides a promising drug delivery system to enhance the oral bioavailability and therapeutic efficacy of DBAE.

Enhanced oral bioavailability and anticancer activity of novel curcumin loaded mixed micelles in human lung cancer cells.

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Patil, Sharvil; Choudhary, Bhavana; Rathore, Atul; Roy, Krishtey; Mahadik, Kakasaheb

2015-11-15

Curcumin has a wide range of pharmacological activities including antioxidant, anti-inflammatory, antidiabetic, antibacterial, wound healing, antiatherosclerotic, hepatoprotective and anti-carcinogenic. However, its clinical applications are limited owing to its poor aqueous solubility, multidrug pump P-gp efflux, extensive in vivo metabolism and rapid elimination due to glucuronidation/sulfation. The objective of the current work was to prepare novel curcumin loaded mixed micelles (CUR-MM) of Pluronic F-127 (PF127) and Gelucire® 44/14 (GL44) in order to enhance its oral bioavailability and cytotoxicity in human lung cancer cell line A549. 3(2) Factorial design was used to assess the effect of formulation variables for optimization of mixed micelle batch. CUR-MM was prepared by a solvent evaporation method. The optimized CUR-MM was evaluated for size, entrapment efficiency (EE), in vitro curcumin release, cytotoxicity and oral bioavailability in rats. The average size of CUR-MM was found to be around 188 ± 3 nm with an EE of about 76.45 ± 1.18% w/w. In vitro dissolution profile of CUR-MM revealed controlled release of curcumin. Additionally, CUR-MM showed significant improvement in cytotoxic activity (3-folds) and oral bioavailability (around 55-folds) of curcumin as compared to curcumin alone. Such significant improvement in cytotoxic activity and oral bioavailability of curcumin when formulated into mixed micelles could be attributed to solubilization of hydrophobic curcumin into micelle core along with P-gp inhibition effect of both, PF127 and GL44. Thus the present work propose the formulation of mixed micelles of PF127 and GL44 which can act as promising carrier systems for hydrophobic drugs such as curcumin with significant improvement in their oral bioavailability. Copyright © 2015 Elsevier GmbH. All rights reserved.

The bioavailability of iron, zinc, protein and vitamin A is highly variable in French individual diets: Impact on nutrient inadequacy assessment and relation with the animal-to-plant ratio of diets.

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Perignon, Marlène; Barré, Tangui; Gazan, Rozenn; Amiot, Marie-Josèphe; Darmon, Nicole

2018-01-01

Nutritional adequacy depends on nutrient intakes and bioavailability which strongly varies with the plant- or animal-origin of foods. The aim was to estimate iron, zinc, protein and vitamin A bioavailability from individual diets, and investigate its relation with the animal-to-plant ratio (A/P) of diets. Bioavailability was estimated in 1899 French diets using diet-based algorithms or food-group specific conversion factors. Nutrient inadequacy was estimated based on i) bioavailability calculated in each individual diet and ii) average bioavailability assumed for Western-diets. Mean iron absorption, zinc absorption, protein quality and β-carotene conversion factor were 13%, 30%, 92%, and 17:1, respectively. Bioavailability displayed a high variability between individual diets, poorly explained by their A/P. Using individual bioavailability led to different inadequacy prevalence than with average factors assumed for Western-diets. In this population, the A/P does not seem sufficient to predict nutrient bioavailability and the corresponding recommended intakes. Nutritional adequacy should be assessed using bioavailability accounting for individual diets composition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioavailability of two oral formulations of triazolam using radioreceptor assay

Energy Technology Data Exchange (ETDEWEB)

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

1986-04-01

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

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

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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

ß-Carotene from Red Carrot Maintains Vitamin A Status, but Lycopene Bioavailability Is Lower Relative to Tomato Paste in Mongolian Gerbils

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Red carrots contain lycopene in addition to ß-Carotene. The utility of red carrot as a functional food depends in part on the bioavailability of its constituent carotenoids. Lycopene bioavailability was compared in Mongolian gerbils (Meriones unguiculatus) fed freeze-dried red carrot and tomato pa...

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

Energy Technology Data Exchange (ETDEWEB)

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

2004-09-15

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

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...

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

DEFF Research Database (Denmark)