Liquid chromatography–mass spectrometry method for the determination of nicardipine in human plasma

A simple and sensitive liquid chromatography–mass spectrometry method is described for the determination of nicardipine in human plasma. Chromatographic separation of the analyte was achieved on a C18 column using a mobile phase of methanol, water and formic acid (320:180:0.4, v/v/v). Selected ion monitoring (SIM) in positive mode was used for analyte quantification at m/z 480.2 for nicardipine and m/z 256.4 for diphenhydramine. The run time was less than 5 min. The linearity over the concentration range of 0.05–20.0 ng/ml for nicardipine was obtained and the lower limit of quantification was 0.05 ng/ml. For each level of QC samples, inter-day and intra-day precisions (R.S.D.) were ≤9.3 and 11.1%, respectively, and accuracy (RE) was ±4.9%. The present LC–MS method was successfully applied in the pharmacokinetic studies of nicardipine hydrochloride delayed-release tablets in two formulations after oral administration to healthy volunteers.