[Pharmacokinetics of praziquantel injection in healthy buffaloes]

Objective To investigate the pharmacokinetics and relative bioavailability of praziquantel injection in buffaloes in contrast to praziquantel tablet. Methods A single oral administration of praziquantel tablet at a dose of 20 mg/kg or intramuscular administration of praziquantel injection at a dose of 10 mg/kg was performed in six healthy adult buffalos according to a twoperiod crossover design. The praziquantel concentration in plasma was determined by a high performance liquid chromatography (HPLC) method. The pharmacokinetic parameters were calculated by non-compartmental analysis. Results The main pharmacokinetic parameters of praziquantel tablet were as follows: T_max = (0.60±0.29)h, C_max = (0.57±0.37)μg/ml, T_1/2β = (0.70±0.42)h, AUC = (0.80±0.70) (μg/ml)·h. The main pharmacokinetic parameters of praziquantel injection were as follows: T_max = (0.65± 0.49)h, C_max = (3.82±1.17)μg/ml, T_1/2β = (1.00±0.73)h, AUC = (1.61±0.89) (μg/ml)·h. The relative bioavailability of praziquantel injection was 402.5% in contrast to praziquantel tablet. Conclusion The praziquantel injection has pharmacokinetic characteristics of rapid absorption, high bioavailability and extensive distribution, and the clinical recommended dosage of praziquantel injection is 10 mg/kg.