Determination of a novel thrombin receptor antagonist (SCH 530348) in human plasma: evaluation of Ultra Performance Liquid Chromatography™-tandem mass spectrometry for routine bioanalytical analysis.

SCH 530348 is a safe and effective oral anti-platelet agent for patients with acute coronary syndrome. Clinical study results suggest that SCH 530348 dosage at 20 mg or 40 mg is feasible to achieve rapid maximum platelet inhibition following an acute coronary event or intervention procedure. To permit accurate determinations of circulating SCH 530348 in plasma following dosing, a method for measuring SCH 530348 concentrations in human plasma was validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method utilized semi-automated 96-well protein precipitation with gradient chromatography using an ACQUITY™ UPLC BEH C18 (2.1 mm×50 mm, 1.7 μm) column. The retention time of SCH 530348 was approximately 1.5 min. This method was validated for routine quantitation of SCH 530348 over the concentration range of 1.00-1000 ng/mL. Inter-run accuracy based on mean percent theoretical for replicate quality control samples was better than 95.2%. Inter-run precision based on percent relative deviation for replicate quality control samples was ≤3.3%. SCH 530348 quality control samples were stable in human plasma for up to three freeze/thaw cycles, for at least 467 days when frozen at -20 °C and for at least 7 h when stored at room temperature. The lower limit of quantitation was 1.00 ng/mL for a 100 μL plasma aliquot.