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Indoxyl sulfate (IS), a highly protein-bound nephro-cardiovascular toxin, was poorly removed by hemodialysis. IS exists as anions in the body and the renal excretion is mediated by organic anion transporter 1 (OAT1) and OAT3. Acidic antibiotics such as cephalosporins and fluoroquinolones were putative substrates/inhibitors of OATs. We hypothesized that cephalosporins and fluoroquinolones might compete with IS for OAT1- and/or OAT3-mediated renal excretions. This study investigated the effects of ciprofloxacin, cefuroxime, cefotaxime, cefazolin and ofloxacin on the intravenous pharmacokinetics of IS in rats. IS was intravenously injected with and without each individual antibiotics, and the concentrations of IS in serum and lysate were determined by HPLC. The results showed that ciprofloxacin significantly increased AUC0-t and T1/2 of IS by 272% and 491%, respectively, and decreased the clearance by 71%. However, ofloxacin, cefuroxime, cefotaxime and cefazolin did not alter the pharmacokinetics of IS. Furthermore, cell line study showed that ciprofloxacin inhibited the OAT3-mediated transport of IS. This study indicates 30 mg/kg of ciprofloxacin decreased the clearance of IS through inhibition on the OAT3-mediated transport, whereas 50 mg/kg of ofloxacin, cefuroxime, cefotaxime and cefazolin did not show significant influence. [ABSTRACT FROM AUTHOR]

1. Rhubarb, rhizome ofRheum palmatum L.(RP), is an important herb in clinical Chinese medicine. 2. Cyclosporine (CSP) is an immunosuppressant with narrow therapeutic window. The oral bioavailability of CSP was associated with P-glycoprotein (P-gp) and CYP 3A4. CSP was used as a probe substrate to investigate thein vivomodulation effects of RP on P-gp and CYP 3A. 3. Rats were orally administered 2.5 mg/kg of CSP with and without 0.25 and 1.0 g/kg of RP. The blood CSP concentration was determined by a specific monoclonal fluorescence polarization immunoassay. 4. Both dosages of RP significantly decreased theCmaxand AUC0–tof CSP in rats. Mechanism studies indicated that RP activated the functions of P-gp and CYP 3A. 5. RP ingestion reduced the systemic exposure of CSP through activating P-gp and CYP 3A. [ABSTRACT FROM PUBLISHER]

An efficient and useful method for the incorporation of colloidal quantum dots (QDs) into ionic matrices is demonstrated. We prepared three different synthesis methods, which are traditional saturated-salt water, methanol-assisted, and ethanol-assisted methods. The continuous thermal and photonic stress tests indicate that the high temperature, instead of photonic excitation stress, is more detrimental to the illumination capability of the quantum dots. While the traditional saturated-salt water synthesis and methanol-assisted method are quite effective in low temperature and low photon excitation intensity, the quantum dots sealed by the ethanol-assisted method cannot hold under all conditions. An over-1000-h aging test can provide crucial information for the longevity of these quantum dots, and more than 10,000 h of lifetime can be expected. [ABSTRACT FROM AUTHOR]

Folium Sennae (leaves of Cassia angustifolia or senna) is a laxative and a component in diets for weight control. It contains a variety of anthranoids such as sennosides, aloe-emodin, and rhein. In order to measure the serum concentrations of senna anthranoids, Sprague-Dawley rats were orally administered with single dose and multiple doses of Folium Sennae. The concentrations of anthranoids in serum were determined by HPLC method before and after hydrolysis with sulfatase and β-glucuronidase. The results showed that in the serum, aloe-emodin glucuronides and rhein glucuronides were the major metabolites. Traces of rhein free form were present transiently during the early phase, whereas the free form of aloe-emodin was not detected. We also evaluated the modulation effect of Folium Sennae on P-glycoprotein by using the LS 180 cell model which showed that it significantly inhibited P-glycoprotein by 16-46 %. In conclusion, senna anthranoids were rapidly and extensively metabolized to rhein glucuronides and aloe-emodin glucuronides in rats. Folium Sennae ingestion inhibited the efflux function of P-glycoprotein in the intestine., (Georg Thieme Verlag KG Stuttgart · New York.)