Determination of picamilon concentration in human plasma by liquid chromatography-tandem mass spectrometry.

A rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of picamilon concentration in human plasma. Picamilon was extracted from human plasma by protein precipitation. High performance liquid chromatography separation was performed on a Venusil ASB C(18) column with a mobile phase consisting of methanol -10mM ammonium acetate-formic acid (55:45:01, v/v/v) at a flow rate of 0.65ml/min. Acquisition of mass spectrometric data was performed in selected reaction monitoring mode, using the transitions of m/z 209.0-->m/z (78.0+106.0) for picamilon and m/z 152.0-->m/z (93.0+110.0) for paracetamol (internal standard). The method was linear in the concentration range of 1.00-5000ng/ml for the analyte. The lower limit of quantification was 1.00ng/ml. The intra- and inter-assay precision were below 13.5%, and the accuracy was between 99.6% and 101.6%. The method was successfully applied to characterize the pharmacokinetic profiles of picamilon in healthy volunteers. This validated LC-MS/MS method was selective and rapid, and is suitable for the pharmacokinetic study of picamilon in humans.