Simultaneous determination of four components in Baige capsule by HPLC: application to pharmacokinetics and tissue distribution of normal and middle cerebral artery occlusion rats.

A sensitive and specific high-performance liquid chromatography (HPLC) method was developed and applied to the pharmacokinetics for simultaneous identification and quantification of four components - puerarin, daidzein, imperatorin and isoimperatorin - in the plasma and tissues of normal and middle cerebral artery occlusion rats after oral administration of Baige capsule. Ferulic was used as the internal standard. The extraction procedure was composed of two independent steps. The plasma was prepared by liquid-liquid extraction with light petroleum-acetic ether (1:1, v/v) first and then protein was precipitated with methanol. The tissue samples were weighted and homogenated with normal saline, then the homogenate was prepared by liquid-liquid extraction and protein precipitation. The parameters of pharmacokinetics were calculated using DAS 2.1.1 software. The calibration curves of all four components in the plasma and tissue homogenates were in good linearity in the measured range with R(2)  ≥ 0.9921. The relative standard deviation of the intra- and inter-day accuracy at different levels was less than ±18.0%. In conclusion, the established method was a simple and effective one to simultaneously detect all four components in the plasma and tissues of rats, and was successfully applied in the pharmacokinetics of Baige capsule.