Comparative pharmacokinetics of dehydroevodiamine and coptisine in rat plasma after oral administration of single herbs and Zuojinwan prescription.

Zuojinwan, which consists of Rhizoma coptidis-Evodia rutaecarpa powder (6:1,g/g), is a traditional Chinese medicine (TCM) prescription, clinically used for the treatment of gastro-intestinal disorders. This study compared the pharmacokinetics of dehydroevodiamine and coptisine, the main active ingredients in Zuojinwan, in rats administrated with whole prescription or single herbs. Multiple blood concentration peaks were observed in the mean plasma-concentration curves. The pharmacokinetic parameters were quite different between single herbs and Zuojinwan prescription. Moreover, the mean plasma concentration of dehydroevodiamine increased and the one of coptisine decreased after combining, which was in accord with the clinical principle of TCM.