Bioequivalence study of two formulations of simvastatin tablets in healthy Thai volunteers

The bioequivalence of two formulations of 10 mg tablets of simvastatin (CAS 79902-63-9), Vascor as test and a commercially available preparation as reference, in 18 healthy Thai male volunteers was assessed. In a randomized, single dose, two-period, crossover study design with a 1-week wash-out period, each subject received 4 tablets of 10-mg simvastatin tablets. Plasma samples were collected over a 24-h period after administration. Subsequently, plasma concentrations of simvastatin and its hydroxy acid metabolite were analyzed by using LC/ MS/MS. Pharmacokinetic parameters were determined by using non-compartmental analysis. The results showed that 90% confidence intervals of the peak concentration (Cmax) and the area under the concentration-time curve (AUC) of simvastatin and its hydroxy acid metabolite of reference and test were within 80 %-125%. Consequently the bioequivalence of these two preparations can be concluded.