COMPARATIVE BIOAVAILABILITY OF 2 TABLET FORMULATIONS OF RANITIDINE HYDROCHLORIDE IN HEALTHY-VOLUNTEERS

This investigation was carried out to evaluate the bioavailability of a new tablet formulation of ranitidine HCl (300 mg), Ranid, relative t o the reference product, Zantac, (300 mg) tablets. The bioavailability was carried out on 24 healthy male volunteers who received a single d ose (300 mg) of the test (T) and the reference (R) products in the fas ting state, in a randomized balanced 2-way crossover design. After dos ing, serial blood samples were collected for a period of 16 hours. Pla sma harvested from blood was analyzed for ranitidine by a sensitive an d validated high-performance liquid chromatographic assay. The maximum plasma concentration (C-max), area under the plasma concentration tim e curve up to the last measurable concentration (AUC(0-t)), and to inf inity (AUC(0-infinity)) and the absorption rate (C-max/AUC(0-infinity) ) were analyzed statistically under the assumption of a multiplicative model. The time to maximum concentration (T-max) was analyzed assumin g an additive model. The parametric confidence intervals (90%) of the mean values of the pharmacokinetic characteristics (AUC(0-t), AUC(0-in finity), C-max and C-max/AUC(0-infinity)) for T/R ratio were in each c ase well within the bioequivalence acceptable range of 80 - 125%. The test formulation was found bioequivalent to the reference formulation by the Schuirmann's two one-sided t-tests and by Wilcoxon Mann Whitney two one-sided tests procedure. Therefore, the 2 formulations were con sidered to be bioequivalent.