Pharmacokinetics and Comparative Bioavailability of Two Metoprolol Tablet Preparations

The bioavailability of a generic preparation of metoprolol (Beatrolol®) was evaluated in comparison with a proprietary product (Betaloc®). Twelve healthy volunteers participated in the study conducted according to a two-way crossover desing. The bioavailability was compared using the parameters, total area under the plasma level-time curve (AUC0-00), peak plasma concentration (Cmax), and time to reach peak plasma concentration (Tmax). No statistically significant difference was observed between the values of the two products in all three parameters. Moreover, the 90% confidence interval for the ratio of the logarithmic tranformed AUC0-00 values of Beatrolol over those of Betaloc was found to lie between 0.93 and 1.07, which is within the acceptable equivalence limit of 0.80-1.25. From the data obtained, it also appeared that a relatively high proportion of our volunteers were poor metabolizers of metoprolol. The mean elimination half-life (t1/2), was found to be relatively larger than those report...