Liquid chromatography tandem mass spectrometry method for the quantification of amisulpride with LLOQ of 100 pg/mL using 100 μL of plasma

A sensitive and selective high-performance liquid chromatography-positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of amisulpride in 100 mu L of human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective (M + H)(+) ions, m/z 370-242 for amisulpride and m/z 341-112 for the internal standard. The assay exhibited a linear dynamic range with a lower range of 0.1-100 ng/mL and a higher range of 1-500 ng/mL of amisulpride in human plasma. The lower limit of quantification was 0.1 ng/mL with a relative standard deviation of less than 10%. Acceptable precision and accuracy were obtained for both linearity ranges. A run time of 2.0 min for each sample made it possible to analyze more than 275 human plasma samples per day. The validated method has been successfully used to analyze plasma samples for application in pharmacokinetic studies. Copyright (C) 2008 John Wiley & Sons, Ltd.