Simultaneous quantitation of atorvastatin and its two active metabolites in human plasma by liquid chromatography/(–) electrospray tandem mass spectrometry

摘要

A sensitive, accurate and selective liquid chromatography–tandem mass spectrometry method(LC–MS/MS) was developed and validated for the simultaneous quantitation of atorvastatin(AT) and its equipotent hydroxyl metabolites, 2-hydroxy atorvastatin(2-AT) and 4-hydroxy atorvastatin(4-AT), in human plasma. Electrospray ionization(ESI) interface in negative ion mode was selected to improve the selectivity and the sensitivity required for this application. Additionally, a solid phase extraction(SPE)step was performed to reduce any ion-suppression and/or enhancement effects. The separation of all compounds was achieved in less than 6 min using a C18reverse-phase fused-corescolumn and a mobile phase, composed of a mixture of 0.005% formic acid in water:acetonitrile:methanol(35:25:40, v/v/v), in isocratic mode at a flow rate of 0.6 mL/min. The method has lower limit of quantitation(LLOQ) of0.050 ng/mL for all analytes. The method has shown tremendous reproducibility, with intra- and inter-day precision less than 6.6%, and intra- and inter-day accuracy within 74.3% of nominal values, for all analytes, and has proved to be highly reliable for the analysis of clinical samples.