Determination of phillyrin in rat plasma by high-performance liquid chromatography and its application to pharmacokinetic studies.

A simple high-performance liquid chromatographic method was developed to study the pharmacokinetics of phillyrin in rat after intravenous administration. Plasma was extracted with ethyl acetate after addition of the internal standard, arctiin. Separation was achieved on a reversed-phase C18 column with UV detection at 228 nm. The calibration curves were linear ranging from 0.052 to 26.670 microg/ml. The intra- and inter-day precisions were no more than 9.83% and 12.31%, respectively. The average recovery of phillyrin was 95.44% from plasma. And the limit of quantification (LOQ) was estimated as 0.026 microg/ml with an intra-day relative standard deviation (R.S.D.)<or=20%. The analytical sensitivity and accuracy of this assay were adequate for characterization of phillyrin in rat plasma and the assay has been applied successfully to the in vivo kinetic study of phillyrin in rats.