Formulation and bioequivalence of two valsartan tablets after a single oral administration

The aim of this study is to assess the quality of Valzan(®) tablet (160 mg, valsartan immediate release test formulation) by comparing its pharmacokinetic parameters with Diovan(®) tablet (160 mg, valsartan reference formulation). Valzan(®) tablets were prepared according to a dry granulation method (roll compaction). To assess the bioequivalence of Valzan(®) tablets a randomized, two-way, crossover, bioequivalence study was performed in 24 healthy male volunteers. The selected volunteers were divided into two groups of 12 subjects. One group was treated with the reference formulation (Diovan(®)) and the other one with the generic Valzan(®), with a cross-over after the drug washout period of 14 days. Blood samples were collected at fixed time intervals and valsartan concentrations were determined by a validated HPLC assay method. The pharmacokinetic parameters AUC(0-48), AUC(0-∞), C(max), T(max), K(e) and T(1/2) were determined for both the tablets and were compared statistically to evaluate the bioequivalence between the two brands of valsartan, using the statistical model recommended by the FDA. The analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals (CI) fell within the acceptable range for bioequivalence. Based on this statistical evaluation it was concluded that the test tablets (Valzan(®)) is well formulated, since it exhibits pharmacokinetic profile comparable to the reference brand Diovan(®).