Pharmacokinetics of osthole in rat plasma using high-performance liquid chromatography.

A simple high-performance liquid chromatographic method was developed to study the pharmacokinetics of osthole in rat plasma. After addition of an internal standard (paeonol), plasma was deproteinized by acetonitrile for sample clean-up. The drugs were separated on a reversed-phase column and detected by UV absorption at 323 nm. Acetonitrile-water-diethylamine (50:50:0.1, v/v/v) (pH 3.0, adjusted with orthophosphoric acid) was used as the mobile phase. It was applied to the pharmacokinetic study of osthole in rats after a dose of 10 mg kg-1 by intravenous administration. A biphasic phenomenon with a rapid distribution followed by a slower elimination phase was observed from the plasma concentration-time curve.