Original Article

A phase I study on pharmacokinetics and pharmacodynamics of higenamine in healthy Chinese subjects

Authors: Sheng Feng, Ji Jiang, Pei Hu, Jian-yan Zhang, Tao Liu, Qian Zhao, Bi-lu Li
DOI: 10.1038/aps.2012.114

Abstract

Aim: To investigate the pharmacokinetics, pharmacodynamics, and safety of higenamine, an active ingredient of Aconite root, in healthy Chinese volunteers.
Methods: Ten subjects received continuous, intravenous infusion of higenamine at gradually escalating doses from 0.5 to 4.0 μg·kg−1·min−1, each dose was given for 3 min. Blood and urine samples were collected at designated time points to measure the concentrations of higenamine. Pharmacodynamics was assessed by measuring the subject's heart rate. A nonlinear mixed-effect modeling approach, using the software Phoenix NLME, was used to model the plasma concentration-time profiles and heart rate.
Results: Peak concentrations (Cmax) of higenamine ranged from 15.1 to 44.0 ng/mL. The half-life of higenamine was 0.133 h (range, 0.107–0.166 h), while the area under concentration-time curve (AUC), extrapolated to infinity, was 5.39 ng·h·mL−1 (range, 3.2-6.8 ng·h·mL−1). The volume of distribution (V) was 48 L (range, 30.8–80.6 L). The total clearance (CL) was 249 L/h (range, 199-336 L/h). Within 8 h, 9.3% (range, 4.6%–12.4%) of higenamine was recovered in the urine. The pharmacokinetics of higenamine was successfully described using a two-compartment model with nonlinear clearance. In the pharmacodynamic model, heart rates were related to the plasma drug concentrations using a simple direct effect model with baseline. The E0, Emax, and EC50 were 68 bpm, 73 bpm and 8.1 μg/L, respectively.
Conclusion: Higenamine has desirable pharmacokinetic and pharmacodynamic characteristics. The results provide important information for future clinical studies on higenamine.
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