Determination of oxymatrine and matrine in human plasma by LC-MS/MS

Objective:To establish a liquid chromatography tandem mass spectrometry(LC-MS/MS) method for the determination of oxymatrine and matrine in human plasma.Methods: The analyses and an internal standard(cimetidine) were extracted from plasma with dichloromethane.The compounds were separated on a ZORBAX-NH2 column by applying LC-MS/MS;10 mmol·L-1 ammonium acetate(0.2% formic acid)-methanol(25∶75) was used as mobile phase at a flow rate of 1.0 mL·min-1.The detection was carried out by means of electrospray ionization tandem mass spectrometry in positive ion mode and multiple reaction monitoring(MRM)mode.Results: The assay had the calibration range from 4.99 to 998.0 ng·mL-1 and lower limit of quantification(LOQ) was 4.99 ng·mL-1 for oxymatrine.The calibration range from 9.71 to 4 855.0 ng·mL-1 and LOQ was 9.71 ng·mL-1 for matrine.The accuracy,precision(intra-day and inter-day),extraction recovery,matrix effects and stability(ambient temperature,freeze storage) of the method fulfilled the analytical validation criteria of the guidelines.Conclusion: The method is simple,accurate,sensitive and specific for the determination of oxymatrine and its metabolite matrine in human plasma.