The purpose of this study was to investigate the pharmacokinetic properties of ephedrine, paeoniflorin, and cinnamic acid after single or multiple doses of Socheongryong-tang (SCRT) were administered to rats, and to present an example of the pharmacokinetic changes following multiple doses of an herbal medicine. SCRT is a traditional herbal medicine that has been used clinically for a long time, and its main ingredients include ephedrine, paeoniflorin, and cinnamic acid. However, studies on the pharmacokinetic properties of SCRT are insufficient, and particularly, no pharmacokinetic information has been reported for multiple doses. In this study, SCRT was administered orally to rats once or multiple times, and plasma sampled at different times was quantitatively analyzed for ephedrine, paeoniflorin, and cinnamic acid using ultra-high-performance liquid chromatography-tandem mass spectrometry. There was a difference between the pharmacokinetic parameter values of each component (especially in paeoniflorin and cinnamic acid) obtained after single or multiple doses of SCRT. The actual observed values of each component obtained after multiple doses of SCRT were clearly different from the predicted results of multiple-dose simulations based on the pharmacokinetic profiles obtained after a single dose. The results confirmed that the plasma concentrations and, thus, exposures to paeoniflorin and cinnamic acid were significantly increased when SCRT was administered multiple times, whereas that of ephedrine was not. The results of this study are expected to provide useful pharmacokinetic data for the safety and efficacy evaluation of SCRT in the future and demonstrate the necessity of pharmacokinetic comparison studies according to single or multiple oral administrations of herbal medicines.
Keywords: Socheongryong-tang; cinnamic acid; ephedrine; paeoniflorin; pharmacokinetic.