DETERMINATION OF WOGONIN IN RAT PLASMA BY LIQUID-CHROMATOGRAPHY AND ITS PHARMACOKINETIC APPLICATION

A high-performance liquid chromatographic method has been developed fo r the determination of wogonin in the rat plasma. After addition of an internal standard (clomipramine), plasma was deproteinized by acetoni trile and centrifuged for sample clean-up. The supernatant was separat ed by a reversed-phase column chromatography, identified by a photodio de-array detector, and quantified by ultraviolet detection at a wavele ngth of 275 nm. Acetonitrile-water-diethylamine (50:50:0.1, v/v/v, pH 3.0 adjusted by orthophosphoric acid) was used as the mobile phase. Th e method was applied to the pharmacokinetic study of wogonin in rats a fter a dose of 5 mg/kg by intravenous administration. A biphasic pheno menon with a rapid distribution followed by a slower elimination phase was observed from the plasma concentration time profile.