400-408 Zhang LAJP 1681:Zhang

A new HPLC-DAD method has been developed and validated for the simultaneous analysis of five flavonoids (rutin, quercitrin, quercetin, kaempferol, and isorahamnetin) in rat plasma. Sample pretreatment consisted of a liquid–liquid extraction. The five flavonoids was separated on a kromasil C18 column and recorded at 350 nm. The greatest resolution was achieved with methanol-0.1% formic acid gradient at a flow rate of 1.0 mL min–1. The correlation coefficients for all the calibration plots (r > 0.999) showed good linearity over the range tested. The relative standard deviation of the method was less than 7% and 10% for intra and inter-day assays respectively, and average recovery was between 77.2 and 99.2%. The detection limits of this method were between 0.006 and 0.02 μg mL–1. The method has been successfully applied to determine drug concentrations in normal and diabetic rat plasma samples and pharmacokinetic of Ginkgo biloba extract.