Determination of solifenacin in human plasma by liquid chromatography-tandem mass spectrometry

A liquid chromatography-electrospray tandem mass spectrometry method was developed and validated to quantitate solifenacin in human plasma The assay was based on protein precipitation with methanol and liquid chromatography performed on a pentafluorophenylpropylsilica column (50 x 4 mm 3 mu m particles) the mobile phase consisted of methanol - 100 mM ammonium acetate containing 1% of formic acid (90 10 v/v) Quantification was through positive-ion mode and selected reaction monitoring at m/z 363 -> 193 and 368 -> 198 for solifenacin and the internal standard solifenacin-D-5 respectively The lower limit of quantitation was 0 47 ng/ml using 0 25 ml of plasma and linearity was demonstrated up to 42 ng/ml Intra-assay and inter-assay precision expressed by relative standard deviation was less than 11% and inaccuracy did not exceed 11% at all levels The assay was applied to the analysis of samples from a pharmacokinetic study (C) 2010 Elsevier B V All rights reserved