Comparative bioavailability study of a generic naltrexone tablet preparation

The bioavailability of a generic preparation of naltrexone (Narpan) was com pared with the innovator product, Trexan. Twelve healthy volunteers partici pated 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-infinity), peak plasma con centration C-max, and time to reach peak plasma concentration T-max. No sta tistically significant difference was observed between the logarithmic tran sformed AUC(0-infinity) and the logarithmically transformed C-max values of the two preparations. Also, no statistically significant difference was ob served between the untransformed T-max values. In addition, the 90% confide nce interval for the ratio of the logarithmic transformed AUC(0-infinity) v alues 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 a nd 1.23, both being within the bioequivalence limit of 0.80-1.25. The numer ical values of the elimination half-life (t(1/2)) obtained with the two pre parations were also nor significantly different and were comparable to thos e reported in the literature.