Abstract: AimTo study the pharmacokinetics of bromotetrandrine (W198) in rats and beagle dogs. MethodsThe concentrations of W198 in serum were determined using HPLC method with UV detection. ResultsThe pharmacokinetic parameters of W198 after single iv doses of W198 10, 20 and 40 mg·kg_-1 in rats were as follows: T_1/2β were 6.60, 7.36 and 6.77 h, AUC_0-24h were 3.797, 7.371 and 15.192 mg·h·L_-1, V_d were 7.14, 4.33 and 4.13 L·kg_-1, CL were 2.83, 2.60 and 2.71 L·(kg·h)_-1, respectively. The T_1/2β and AUC_0-24h of W198 after single im dose of W198 20 mg·kg_-1 in rats were 11.61 h and 12.646 mg·h·L_-1. The im bioavailability of W198 in rats was 56.9%. The T_1/2β, AUC_0-24h, V_d and CL of W198 after single iv dose of W198 5 mg·kg_-1 in beagle dogs were 11.72 h, 12.646 mg·h·L_-1, 0.70 L·kg_-1 and 0.46 L·(kg·h)_-1, respectively. The plasma protein binding ratio of W198 with human serum protein was 78.0%. ConclusionThe absorption of W198 in rats was of first order kinetics.