DETERMINATION OF DIHYDRO-5,6-DEHYDROKAWAIN IN RAT PLASMA BY HPLC AND ITS PHARMACOKINETICS APPLICATION

A simple high performance liquid chromatographic method was developed to study the pharmacokinetics of dihydro-5,6-dehydrokawain (DDK) in th e rat plasma. After addition of an internal standard (osthole), plasma was deproteinized by acetonitrile for sample clean-up. The drugs were separated on a reverse phase column and detected by UV detection at a wavelength 281 nn. Acetonitrile-water-diethylamine (50:50:0.1, v/v/v, pH 3.0 adjusted by orthophosphoric acid) was used as a mobile phase. It was applied to the pharmacokinetic study of DDK in rats after a dos e of 5 mg/kg intravenous administration. A biphasic phenomenon with a rapid distribution followed by a slower elimination phase was observed from the plasma concentration-time curve.