An HPLC method for the determination of nifekalant hydrochloride in canine plasma and its application to a pharmacokinetic study.

In this study, a simple and selective high-performance liquid chromatography method was developed and validated for the determination of nifekalant hydrochloride in canine plasma. Liquid-liquid extraction was used to separate nifekalant hydrochloride from canine plasma and the mean extraction recoveries of nifekalant hydrochloride and the internal standard were 82.31 and 94.81%, respectively. The chromatographic separation was performed on a Dikma Diamonsil column with a mobile phase consisting of acetonitrile-20mM phosphate buffer (pH 6.2; 30:70, v/v) with flow rate of 1.0 mL/min. The standard curve was linear over the concentration range of 20-10,000 ng/mL (r(2) > 0.99). The intra-batch and inter-batch accuracy for nifekalant hydrochloride at four concentrations were 93.14-100.47% and 96.12-103.77%, respectively. The relative standard deviations were less than 15%. The method was successfully applied to a pharmacokinetic study after the intravenous administration of nifekalant hydrochloride to beagle dogs.