ABSTRACT
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 intramus-cular administration of praziquantel injection at a dose of 10 mg/kg was performed in six healthy adult buffalos according to a two-period 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 pharma-cokinetic parameters of praziquantel tablet were as follows:Tmax=(0.60±0.29)h,Cmax=(0.57±0.37)μg/ml,T1/2β=(0.70±0.42) h,AUC=(0.80±0.70)(μg/ml)·h. The main pharmacokinetic parameters of praziquantel injection were as follows:Tmax=(0.65± 0.49)h,Cmax=(3.82 ± 1.17)μg/ml,T1/2β=(1.00 ± 0.73)h,AUC=(1.61 ± 0.89)(μg/ml)·h. The relative bioavailability of pra-ziquantel 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 pra-ziquantel injection is 10 mg/kg.