Abstract

A very simplistic, selective, sensitive, and reproducible procedure based on a reversed-phase high-performance liquid chromatography was used and developed for the determination of praziquantel in rat plasma. For the separation of praziquantel from the internal standard (diazepam) on a C18 column, enable (250×4.6 mm, 5 µm particle size), with the retention time of 6.4, 8.5 min, respectively. For praziquantel with UV detector at 225 nm. The mobile phase was a mixture of acetonitrile:water in a ratio of (60:40 v/v), running through the column at the flow rate of 1 ml/min. Sample preparation of 200 µl of plasma was done by a protein precipitation by using perchloric acid. Calibration curve was found to be linear with correlation coefficients (r²) is 0.9989 prepared in plasma at the concentrations of 5 to 1000 ng/ml. The precision of the above method was based on interday, and intraday repeatability, and reproducibility (day-to-day variation) were found to be within the limit of 15%. Limit of quantification was accepted and found to be 5 ng/ml using 200 µl samples. The method appears to be robust and has been applied to a pharmacokinetic study of praziquantel in three groups of rats with a single oral dose of 40 mg/kg body weight.