Pharmacokinetics of Active Components of Yokukansan, a Traditional Japanese Herbal Medicine after a Single Oral Administration to Healthy Japanese Volunteers: A Cross-Over, Randomized Study

. YKS is used to treat neurosis, insomnia, as well as behavioral and psychological symptoms of dementia.To confirm the exposure and pharmacokinetics of the active components of YKS in healthy volunteers.A randomized, open-label, 3-arm, 3-period, crossover trial was conducted on 21 healthy Japanese volunteers at the Kochi Medical University between May 2012 and November 2012.Single oral administration of YKS (2.5 g, 5.0 g, or 7.5 g/day) during each period.Plasma concentrations of three active compounds in YKS, namely 18β-glycyrrhetinic acid (GA), geissoschizine methyl ether (GM), and hirsuteine (HTE). of GA were 57.7–108 ng/mL, 8.00–8.01 h, and 9.39–12.3 h, respectively.We demonstrated that pharmacologically active components of YKS are detected in humans. Further, we determined the pharmacokinetics of GM, HTE, and GA. This information will be useful to elucidate the pharmacological effects of YKS