Pharmacokinetic Study of Ipriflavone in Healthy Volunteers by HPLC and Determination of the Relative Bioavailability of Its Tablet Preparation

Two kinds of Ipriflavone tablets (IP) were orally cross administered to 8 healthy volunteers. The serum level of IP at different time was determined by HPLC, 3P87 pharmacokinetic package was used in the analysis of the time course of serum concentration and it had shown that the data well fitted a 2 compartment model. Pharmacokinetic parameters and area under curve (AUC) were calculated. The relative bioavailability of Tabellae IP made in China vs that made in Japan (as a reference) was 1.003( P >0.05). The values of AUC T max and C max of the two preparations were also comparable by the statistical analysis, so they were bioequivalent.

The chemical characteristics of different sodium iron ethylenediaminetetraacetate sources and their relative bioavailabilities for broilers fed with a conventional corn‑soybean meal diet

Background Our previous studies demonstrated that divalent organic iron(Fe)proteinate sources with higher complexation or chelation strengths as expressed by the greater quotient of formation(Qf)values displayed higher Fe bioavailabilities for broilers.Sodium iron ethylenediaminetetraacetate(NaFeEDTA)is a trivalent organic Fe source with the strongest chelating ligand EDTA.However,the bioavailability of Fe when administered as NaFeEDTA in broilers and other agricultural animals remains untested.Herein,the chemical characteristics of 12 NaFeEDTA products were determined.Of these,one feed grade NaFeEDTA(Qf=2.07×10^(8)),one food grade NaFeEDTA(Qf=3.31×10^(8)),and one Fe proteinate with an extremely strong chelation strength(Fe-Prot ES,Qf value=8,590)were selected.Their bioavailabilities relative to Fe sulfate(FeSO_(4)·7H_(2)O)for broilers fed with a conventional corn-soybean meal diet were evaluated during d 1 to 21 by investigating the effects of the above Fe sources and added Fe levels on the growth performance,hematological indices,Fe contents,activities and gene expressions of Fe-containing enzymes in various tissues of broilers.Results NaFeEDTA sources varied greatly in their chemical characteristics.Plasma Fe concentration(PI),transferrin saturation(TS),liver Fe content,succinate dehydrogenase(SDH)activities in liver,heart,and kidney,catalase(CAT)activity in liver,and SDH mRNA expressions in liver and kidney increased linearly(P<0.05)with increasing levels of Fe supplementation.However,differences among Fe sources were detected(P<0.05)only for PI,liver Fe content,CAT activity in liver,SDH activities in heart and kidney,and SDH mRNA expressions in liver and kidney.Based on slope ratios from multiple linear regressions of the above indices on daily dietary analyzed Fe intake,the average bioavailabilities of Fe-Prot ES,feed grade NaFeEDTA,and food grade NaFeEDTA relative to the inorganic FeSO_(4)·7H_(2)O(100%)for broilers were 139%,155%,and 166%,respectively.Conclusions The bioavailabilities of organic Fe sources relative to FeSO_(4)·7H_(2)O were closely related to their Qf values,and NaFeEDTA sources with higher Qf values showed higher Fe bioavailabilities for broilers fed with a conventional corn-soybean meal diet.

Effect of Enzymes in Buccal Mucous Membrane on Buccal Absorption of Insulin

To evaluate the effect of proteolytic enzymes on the absorption of insulin in the buccal mucosa, the trichloroacetic acid (TCA) method was used to estimate the degradation of insulin under different conditions in the buccal mucosal homogenates. In vivo experiments estimating the enhancement of hypoglycaemic effect by enzyme inhibitors were also conducted. The results showed that proteolytic enzymes in the buccal mucosa were less active than in the intestine. Bacitracin, aprotinin and sodium deoxycholate could inhibit the degradation of insulin in the buccal mucosal homogenates. The degradation of insulin in buccal mucosal homogenates of normal hamsters was smaller than that of diabetic hamsters. In vivo experiments of hypoglycaemia supported the in vitro results. When given buccally, bacitracin, aprotinin and sodium deoxycholate could increase the relative pharmacological bioavailability of insulin. When co-administered with aprotinin(0.1%), bacitracin(0.5%) and sodium deoxycholate(5%), the relative pharmacological bioavailabilities of insulin were 4.84%, 6.60% and 14.95% respectively. The in vitro and in vivo results suggest that proteolytic enzymes are present in the buccal mucosa, which limit absorption of insulin. Co-administration with some enzyme inhibitors can improve the bioavailability of insulin via buccal delivery and sodium deoxycholte is more efficient than some enzyme inhibitors used for improving buccal absorption.

Preparation of sorafenib self-microemulsifying drug delivery system and its relative bioavailability in rats

Sorafenib is a novel antitumor drug,which is poorly absorbed in the gastrointestinal tract due to its low solubility in water.To improve the bioavailability of sorafenib,a self-microemulsifying drug delivery system(SMEDDS) formulation of sorafenib was prepared and its relative bioavailability in rats was evaluated.The blank SMEDDS was prepared from a mixture of ethyl oleate(oil phase,20%,w/w),Cremophol EL(surfactant,48%,w/w),PEG-400(co-surfactant,16%,w/w) and ethanol (co-surfactant,16%,w/w).Sorafenib was subsequently dissolved in the blank SMEDDS to obtain a sorafenib SMEDDS formulation with a final sorafenib concentration at 20 mg/mL.The particle size of the emulsified sorafenib SMEDDS was about 20-25 nm. Compared with sorafenib suspension,the prepared SMEDDS formulation exhibited no effect on the T_(max),but significantly increased the AUC,C_(max) and MRT and decreased the drug clearance.Most importantly,the oral bioavailability based on AUC_(0-72h) increased about 25 times after formulating sorafenib in SMEDDS.We concluded that SMEDDS could be a promising vesicle for the oral delivery of the poorly soluble antitumor drug sorafenib.

Preparation of sorafenib self-microemulsifying drug delivery system and its relative bioavailability in rats

Sorafenib is a novel antitumor drug, which is poorly absorbed in the gastrointestinal tract due to its low solubility in water. To improve the bioavailability of sorafenib, a self-microemulsifying drug delivery system （SMEDDS） formulation of sorafenib was prepared and its relative bioavailability in rats was evaluated. The blank SMEDDS was prepared from a mixture of ethyl oleate （oil phase, 20%, w/w）, Cremophol EL （surfactant, 48%, w/w）, PEG-400 （co-surfactant, 16%, w/w） and ethanol （co-surfactant, 16%, w/w）. Sorafenib was subsequently dissolved in the blank SMEDDS to obtain a somfenib SMEDDS formulation with a final sorafenib concentration at 20 mg/mL. The particle size of the emulsified sorafenib SMEDDS was about 20-25 nm. Compared with sorafenib suspension, the prepared SMEDDS formulation exhibited no effect on the Tmax, but significantly increased the AUC, Cmax and MRT and decreased the drug clearance. Most importantly, the oral bioavailability based on AUC0-72h increased about 25 times after formulating sorafenib in SMEDDS. We concluded that SMEDDS could be a promising vesicle for the oral delivery of the poorly soluble antitumor drug sorafenib.

Bioavailability of Arsenic and Antimony in Terrestrial Ecosystems:A Review

Arsenic (As) and antimony (Sb) are metalloids that belong to group 15 of the periodic table and exhibit toxic properties in the environment. They mostly occur naturally at low concentrations in soil, although these can be significantly elevated in both aquatic and terrestrial food chains as a result of dispersion from anthropogenic sources, e.g ., mining activities. The bioavailability, i.e., the proportion of the contaminant in soil and dust that is available for uptake by plants and other living organisms, presents the greatest risk to terrestrial ecosystems. Various in vivo and in vitro methods have been used to measure As and Sb bioaccessibility in soil and dust. In vivo measurement of bioavailability can be time consuming, expensive, and unethical;thus, in vitro methods are commonly preferred. However, there is considerable uncertainty around the efficacy of in vitro tools used to measure the bioavailable fractions of As and Sb. The results of these methods are dependent on many variables, e.g., soil characteristics, contaminant sources, and chemical composition of in vitro methods. Therefore, substantial variations are observed between in vitro and in vivo results obtained from different test animals and endpoints. In this paper, we review the literature on As and Sb bioavailability in terrestrial ecosystems and current in vivo and in vitro techniques used for assessing bioavailability and bioaccessibility of metalloids. This would reveal research gaps and allow scientists and environmental policy makers to gain a deeper understanding of the potential risks associated with these metalloids in the environment.