Column-switching high-performance liquid chromatographic assay for determination of asiaticoside in rat plasma and bile with ultraviolet absorbance detection

A column-switching high-performance liquid chromatography (HPLC) method is described for the determination of asiaticoside in rat plasma and bile using column-switching and ultraviolet (UV) absorbance detection. Plasma was simply deproteinated with acetonitrile prior to injection and bile was directly injected onto the HPLC system consisting of a clean-up column, a concentrating column, and an analytical column, which were connected with two six-port switching valves. Detection of asiaticoside was accurate and repeatable, with a limit of quantification of 0.125 mu g/ml in plasma and 1 mu g/ml in bile. The calibration curves were linear in a concentration range of 0.125-2.5 mu g/ml and 1-20 mu g/ml for asiaticoside in rat plasma and bile, respectively. This method has been successfully applied to determine the level of asiaticoside in rat plasma and bile samples from pharmacokinetics and biliary excretion studies. (C) 1999 Elsevier Science B.V. All rights reserved.