The Pharmacokinetics And Bioequivalence Of Rosuvastatin Calcium Tablets In Healthy Volunteers

Objective: Rosuvastatin, a novel and highly ef fective inhibitor of3-hydroxy-3-methylglutaryl-coen zyme A(HMG-Co A) reductase enzyme.In this paper, a LC-MS/MS method has been developed for the determination of rosuvastatin in plasma samples, and it was used in the pharmacokinetics and bioequivalence studies of rosuvastatin calcium tablets in Chinese healthy volunteers.Methods: The pharmacokinetics and bioequivalence of two rosuvastatin calcium tablets were studied among 19 healthy male volunteers taking a single oral dose of 10 mg test formulation or reference formulation according to a randomized two-crossover design. Blood samples were collected at the designed moment before and after administration. The concentration of rosuvastatin in plasma was determined by LC-MS/MS. Rosuvastatin was extracted from 500 μL of human plasma with methyl tertiary butyl ether.Deuterium-labeled(d6) rosuvastatin was selected as internal standards(IS).The analyte was separated on a Capcell PAK MG C18(50×4.6 mm I.D.,5 μm)analytical column connected with a C18(4×3.0 mm I.D.,5 μm)guard column using methanol-acetonitrile-water-formic acid(55: 5: 40:1,v/v/v/v)as the mobile phase at a flow rate of 0.6 ml/min. A quadrupole tandem mass spectrometer equipped with electrospray ionization source was used as the detector and operated in the positive ion mode. Selected-reaction monitoring(SRM) using the precursor to product ion combinations of m/z 482 to m/z 258.3and m/z 488 to m/z 264.4 were used to quantify rosuvastatin and the corresponding deuterium-labeled rosuvastatin(d6). Pharmacokinetic parameters were calculated by DAS 2.1.1 sofware. The bioequivalence of two formulations was evaluated by two one-sided t test and [1-2α]confidential interval calculation of logarithmic transformed Cmax and AUC.Tmax was analysized on the base of non-parametric Wilcoxon signed rank test.Results: The linear calibration curves were obtained among the concentration range of 0.10-50.00 ng/ml, and the limit of quantification was0.1 ng/ml. For plasma samples of rosuvastatin at 0.20, 2.00, and 40.0ng/ml, the intra-day RSDs(%) were 15.0, 4.1 and 6.0, the inter-day RSDs(%)were 19.0, 12.8 and 12.2, the accuracies(%) were 100.2, 99.7 and 104.2 and extraction recoveries were(86.2±11.5)%,(94.4%±13.1)% and(85.2±10.9)%, respectively. The recovery of the IS at 40.0 ng/ml was( 92.8±12.1)%.The matrix effect determined at two concentrations(0.20 and 40.0 ng/ml for rosuvastatin) were 112.5% and 106.9%, and their relative errors were both within 5.5%. Stability studies revealed that rosuvastatin was stable in plasma for 6 h at room temperature, at the end of three successive freeze and thaw cycles and for 35 d at-70°C. The main pharmacokinetic parameters of test and reference formulation taked by 19 healthy male volunteers at a dose of 10 mg were as followings: Cmax(17.57±10.02) ng/ml and(16.96±8.56) ng/ml, Tmax(3.9±1.7) h and(3.6±1.3) h, AUC0-72h(161.16±86.53) ng/ml·h and(153.94±74.70) ng/ml·h, AUC0-∞(164.15±88.44) ng/ml·h and(156.07±75.17)ng/ml·h, t1/2(9.1±4.3) h and(8.1±2.8) h. The relative bioavailability of test to reference preparation was(108.0±28.8)% according to AUC0-72 h. Cmax, AUC0-∞and AUC0-72 h were evaluated by ANOVA, two one-sided t test and [1-2α]confidential interval test, and Tmax by Wilcoxon’s non-parameter rank-sum test.The results indicated that there is no significant difference between the two formulations of rosuvastatin calcium tablets(P>0.05).Conclusion: The method for determination of rosuvastatin in human plasma was selective, sensitive, accurate, precise and reliable, It was fully validated on the selectivity, linearity, LLOQ, accuracy, and precision, matrix effect,stability, and was successfully applied in the study of pharmacokinetics and bioequivalence of rosuvastatin. Compared with the results reported in literatures, the pharmacokinetic profiles of Chinese were significantly different from those of Caucasian indicating that there were remarkableindividual and racial differences for rosuvastatin. Chinese had higher plasma concentration than Caucasian under the same dosage. The statistical analysis of Cmax, AUC0-∞and AUC0-72 h indicated that the two preparations of rosuvastatin were bioequivalent.