A LC-MS/MS method has been developed for the estimation of rosuvastatin in human plasma using atorvastatin as internal standard. Rosuvastatin is a lipid-lowering drug prescribed for the treatment of hyper-cholestrolemia and dyslipidimia. Solid phase extraction (SPE) was used for the purification and pre-concentration of analyte from human plasma matrix. The chromatographic separation was achieved within 6.0 min by an isocratic mobile phase containing 0.2% formic acid in water and acetonitrile (40: 60, v/v), flowing through YMC J' Sphere ODS H-80, 150 x 4.6 mm, 4.0 µm analytical column, at a flow rate of 1.0 mL min-1 with split of 200 µL to mass spectrometer and 800 µL to waste. Multiple reaction monitoring (MRM) transitions were measured in the positive mode at m/z 482 and 258 for rosuvastatin and m/z 559 and 440 for internal standard respectively. A detailed validation of the method was performed as per USFDA guidelines and the standard curves were found to be linear in the range 1.0 ng mL-1 to 50.0 ng mL-1 with the mean correlation coefficient more than 0.99. The absolute recovery was more than 50.14% for rosuvastatin and 54.65% for internal standard. In human plasma, rosuvastatin was stable for 138 days at -70 ± 5 °C and for 24 hours at ambient temperature. After extraction from plasma, the reconstituted samples of rosuvastatin were stable in auto sampler at 10 °C for 8 hours. Upon subjecting to three freeze thaw cycles, there was no change in the recovery of the analyte. The method was simple, specific, sensitive, precise, accurate and suitable for bioequivalence and pharmacokinetic studies. It was successfully applied to the pilot bioequivalence study of rosuvastatin 20 mg tablets of M/s Zydus Cadila health care Ltd. India versus 20 mg Crestor tablet of M/s Astra Zeneca, USA; in male human subjects.
rosuvastatin; human plasma; validation; bioequivalence
