Analysis of the constituents in rat plasma after oral administration of Shexiang Baoxin pill by HPLC-ESI-MS/MS.

A valid method using liquid chromatography coupled with electrospray ionization (ESI) and ion trap mass spectrometry was established for the study of the absorbed components in rat plasma after oral administration of a traditional Chinese medicine (TCM) Shexiang Baoxin pill. The plasma was deproteinated by adding methanol prior to liquid chromatography, in which separation was carried out on a Symmetry C(18) column (5 microm, 250 x 4.6 mm). A linear gradient with 0.5% formic acid-water-acetonitrile was used as mobile phase. Mass spectra were acquired in both negative and positive modes. Twenty-one components including 17 components from Shexiang Baoxin pill and four metabolites were observed from a comprehensive analysis of the chromatography of Shexiang Baoxin pill, controlled plasma and dosed plasma. All of the 17 prototype compounds and three of the metabolites were identified by comparing their retention behaviors and MS and MS/MS spectra with reference compounds and literature data. This study developed an integrated method for screening the bioactive constituents in plasma after oral adminstration of Chinese herbal medicine and provided helpful chemical information for further pharmacology and active mechanism research on TCM.