title: Pharmacokinetics and Pharmacodynamics of a New Calcium Channel Blocker MPC-1304 in Hypertensive Subjects.
abstract: The pharmacokinetic and pharmacodynamic properties of a new calcium channel blocker MPC-1304 (MPC) were examined following a single 10 mg oral dose of MPC in six hypertensive subjects. Blood samples for measurement of MPC and its active metabolite (MPC-Keto-H(2)) were obtained, and blood pressure was measured just before and at 1, 2, 4, 6, 8, 12 and 24 h after administration. Plasma concentrations of MPC-Keto-H(2) were significantly higher than those of MPC at every observation point. The value of maximum plasma concentration of MPC-Keto-H(2) was 10 times greater than that of MPC. The antihypertensive effect of MPC was observed at 4 h after administration and persisted up to 8 h. A plot of plasma concentrations of MPC versus reductions in blood pressure showed an anticlockwise hysteresis loop. These results suggest that the active metabolite MPC-Keto-H(2) contributes in part to the antihypertensive action of MPC, the delayed distribution of MPC into the effector site, or both.
authors.affiliation: Department of Clinical Pharmacology, Jichi Medical School, Tochigi, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kumagai
authors.forename: Akio
authors.initials: A
authors.lastname: Fujimura
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Shiga
authors.forename: Ken-ichiro
authors.lastname: Sunaga Ki
authors.forename: Kyo-ichi
authors.lastname: Ohashi Ki
authors.forename: Akio
authors.initials: A
authors.lastname: Ebihara