Bioavailability and Pharmacokinetics of Acyclovir Tablet Preparation

Abstract

The bioavailability of a generic preparation of acyclovir (Avorax) was compared with the innovator product, Zovirax. Twelve healthy volunteers participated in the study, conducted according to a randomized, two-way crossover design. The preparations were compared using the parameters area under the plasma concentration-time curve (AUC_0∞), peak plasma concentration (C_max, and time to reach peak plasma concentration T_max. No statistically significant difference was observed between the T_max or the logarithmic transformed AUC_0∞ and C_max values of the two preparations. In addition, the 90% confidence interval for the ratio of the logarithmic transformed AUC_0∞ values of Avorax over those of Zovirax was found to lie between 0.85 and 1.06, while that of the logarithmic transformed C_max values was between 0.95 and 1.25, being within the bioequivalence limit of 0.80–1.25. Moreover, the elimination rate constant (k_e), elimination half-life (t_1/2), and apparent volume of distribution (V_d) values obtained with the two preparations were comparable and not significantly different statistically.