ABSTRACT
The lack of authentic standards has limited the quantitative analysis of herbal drugs in biological samples. The present work demonstrated a practicable strategy for the assay of herbs and their metabolites independent of authentic standards. A liquid chromatography- electrospray ionization-mass spectrometry [LC-ESI-MS] method for the qualitative and quantitative determination of the metabolites after oral administration of Rhizome coptidis and Zuojinwan preparation in rat urine has been developed. Urine samples, extracted with a protein precipitation procedure were separated on a C[18] column using a mixture of water [containing 0.1% formic acid] and acetonitrile [30:70, v/v] as mobile phase. The detection was performed via MS with electrospray ionization interface in positive selected reaction monitoring [SRM] mode. One urine sample after administration was selected as standard. The method validation was carried out according to a conventional method which was calibrated by authentic standards. The fully validated method was applied to the pharmacokinetic study of 2,9-demethyljateorhizine-3-sulfate, 13-methoxyjateorhizine-3- glucoronide and 6-methyljateorhizine-5-glucoronide in rat urine. The results could provide evidence to explain the combination of Rhizome coptidis and Evodiae fructus in terms of elimination