The objectives of the present study were to assess pharmacokinetics, pharmacodynamics, tolerability and safety of intravenous administration of bivalirudin, a direct thrombin inhibitor, in healthy Chinese subjects. 48 subjects were equally divided into 4 groups (0.5 mg/kg, 0.75 mg/kg, 1.05 mg/kg intravenous bolus, and 0.75 mg/kg intravenous bolus followed by an infusion of 1.75 mg/kg per hour for 4 h) by a randomized, single-blind and placebo-controlled (bivalirudin groups: n=9/group; placebo groups: n=3/group) design. The safety observations showed that bivalirudin was well tolerated in the studied dose range, all adverse events were mild in severity. The half-life of bivalirudin was approximately 0.57 h (34 min), exposure increased in a dose-dependent manner. In group receiving a 0.75 mg/kg intravenous bolus followed by 1.75 mg/kg per hour infusion for 4 h, bivalirudin concentrations remained at 5000—5500 μg/l within the 4 h infusion period, which was similar to the reported data of Caucasian patients and can provide the desired anticoagulant effects. There was a strong correlation between bivalirudin concentration and anticoagulant effect. A Sigmoid model was used to fit the pharmacodynamic parameters activated clotting time (ACT), activated partial thromboplastin time (APTT) and prothrombin time (PT) and bivalirudin concentrations. The findings of this study suggest that the same dosing regimens of bivalirudin may be administered to Chinese and Caucasian patients. Ongoing and future studies in large populations may add further information.
2011 The Pharmaceutical Society of Japan