Liquid chromatographic - electrospray tandem mass spectrometric method for the quantification of nimodipine in human plasma

A simple, sensitive and rapid liquid chromatography/electrospray ionization tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of nimodipine, a calcium channel blocker, in human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse phase C-18 column and analyzed by MS in the multiple reaction monitoring mode using the respective [M + H](+) ions, m/z 419/343 for nimodipine and m/z 409/228 for the IS. The assay exhibited a linear dynamic range of 0.2-50 ng/mL for nimodipine in human plasma. The lower limit of quantification was 200 pg/mL with a relative standard deviation of less than 8%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 3 min for each sample made it possible to analyze more than 250 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies.