Liquid chromatography-tandem MS/MS method for simultaneous quantification of paracetamol, chlorzoxazone and aceclofenac in human plasma: An application to a clinical pharmacokinetic study

Abstract

A facile, fast and specific method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous quantitation of paracetamol, chlorzoxazone and aceclofenac in human plasma was developed and validated. Sample preparation was achieved by liquid-liquid extraction. The analysis was performed on a reversed-phase C-18 HPLC column (5m, 4.6x50mm) using acetonitrile-10mM ammonium formate pH3.0 (65:35, v/v) as the mobile phase where atrovastatin was used as an internal standard. A very small injection volume (3L) was applied and the run time was 2.0min. The detection was carried out by electrospray positive and negative ionization mass spectrometry in the multiple-reaction monitoring mode. The developed method was capable of determining the analytes over the concentration ranges of 0.03-30.0, 0.015-15.00 and 0.15-15.00g/mL for paracetamol, chlorzoxazone and aceclofenac, respectively. Intraday and interday precisions (as coefficient of variation) were found to be 12.3% with an accuracy (as relative error) of +/- 5.0%. The method was successfully applied to a pharmacokinetic study of the three analytes after being orally administered to six healthy volunteers