Comparative Bioavailability Study of a Generic Naltrexone Tablet Preparation

Abstract

The bioavailability of a generic preparation of naltrexone (Narpan) was compared with the innovator product, Trexan. Twelve healthy volunteers participated in the study, conducted according to a completely 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 logarithmic transformed AUC_0–∞ and the logarithmically transformed C_max values of the two preparations. Also, no statistically significant difference was observed between the untransformed T_max values. In addition, the 90% confidence interval for the ratio of the logarithmic transformed AUC_0–∞ values of Narpan over those of Trexan was found to lie between 0.87 and 1.01, while that of the logarithmic transformed C_max values was between 0.94 and 1.23, both being within the bioequivalence limit of 0.80–1.25. The numerical values of the elimination half-life (t_1/2) obtained with the two preparations were also not significantly different and were comparable to those reported in the literature.