Simultaneous Determination of Rosuvastatin, Rosuvastatin-5S-lactone, and N-desmethyl Rosuvastatin in Human Plasma by UPLC-MS/MS and Its Application to Clinical Study

Objective A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay was developed and validated for the simultaneous quantification of rosuvastatin (RST), rosuvastatin-5 S-lactone (RSTL), and N-desmethyl rosuvastatin (DM-RST) in human plasma. Methods Sample was prepared by liquid-liquid extraction with ethyl acetate from 100 mu L acidulated buffered plasma. Then analytes were chromatographically separated using an Acquity UPLC HSS T3 column (3.0 mm x 100 mm, 1.8 mu m) by 0.1 % formic acid and gradient acetonitrile at a flow rate of 0.30 mL/min. Three analytes and internal standards (carbamazepine) were eluted in 3.5 min. Mass spectrometry detection was performed through positive ion electrospray ionization (ESI). Results The calibration curves for three analytes were linear (R = 0.9987, n = 3) within the concentration range of 0.1-50 ng/ mL for RST and RSTL, and 0.2-100 ng/mL for DM-RST. Mean extraction recoveries were enhanced by means of acidulated plasma using ammonium acetate of pH 4.0, which ranged within 75.3-98.8 % for three analytes. Intra-and inter precision and accuracy were 88.2-96.4 %. Conclusions This present method was lower LLOQ, less time consuming (3.5 min), less plasma consuming (100 mu L) and simpler sample preparation. And it was successfully applied to determine steady state concentrations of RST, RSTL and DMRST in a clinical study of RST for patients with coronary artery disease (CAD).