Estimation of p-coumaric acid as metabolite of E-6-O-p-coumaroyl scandoside methyl ester in rat plasma by HPLC and its application to a pharmacokinetic study

A rapid and simple high-performance. liquid chromatographic (HPLC) method has been developed for the determination of p-coumaric acid in rat plasma and applied to a pharmacokinetic study in rats after administration of a prodrug, E-6-O-p-coumaroyl scandoside methyl ester, isolated from Hedyotis diffusa (Willd.). Sample preparation involved protein precipitation with acetonitrile. The supernatant was then injected onto a DiamonsilTM C-18 column (250 mm x 4.6 min i.d., 5 mu m). The mobile phase consisted of acetonitrile-water (21:79, v/v) with 1% glacial acetic acid. The UV detector was set at 310 run. The lower limit of quantification of p-coumaric acid in rat plasma was 0.02 mu g/mL. The calibration curves were linear over the concentration range 0.02-5 mu g/mL with correlations greater than 0.999. The assay procedure was applied to the study of the metabolite phari-nacokinetics of E-6-O-p-coumaroyl scandoside methyl ester in rat. (c) 2005 Elsevier B.V. All rights reserved.