Development and validation of a liquid chromatography/ mass spectrometry method for the simultaneous quantitation of rosuvastatin and ezetimibe in human plasma.

A simple, rapid, and sensitive LC/electrospray ionization (ESI)-MS method was developed and validated for the simultaneous determination of rosuvastatin (ROS) and ezetimibe (EZE) in human plasma. Following liquid-liquid extraction, the analytes and an internal standard, atorvastatin (ATO), were separated using an isocratic mobile phase comprising 0.1% (v/v) formic acid-methanol (20 + 80, v/v) on an RP-C18 column. Detection was performed on a mass spectrometer by selected ion monitoring using their respective [M-H]- ions, m/z 480 for ROS, m/z 408 for EZE, and m/z 557 for ATO. For both analytes, the method was linear in the range of 0.1 to 10 nglmL. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 4 min made it possible to determine many plasma samples/day. The validated LC/ESI-MS method can be used to study pharmacokinetics, bioavailability, and bioequivalence of combined dosage forms of ROS and EZE.