Comparative Bioavailability of Ranitidine Tablets in Healthy Volunteers

The pharmacokinetic parameters of domestic and imported ranitidine hydrochloride tablets (Ranitidine, formulated and manufactured by Kharazmi Pharmaceuticals, Iran, and Zantac  manufactured by Glaxo, UK) were measured in 14 healthy subjects following oral administration of a single 300-mg dose of each brand and compared for bioequival ence evaluation. The pharmaceutical equivalency of both formulations was shown by in vitro characterization and dissolution testing. The comparative bioavailability of the two products was then determined in a single-blind, single dose, randomized, cross-over study in 14 healthy volunteers. A sensitive, rapid and precise high performance liquid chromatography (HPLC) method was used to measure concentrations of ranitidine in plasma samples collected up to 12 hours following each dose. Pharmacokinetic parameters, including Cmax, Tmax, AUC0-t, AUC0-∞, elimination rate constant (k) and hal f life were determined for both formulations. Analysis of the data revealed that the vari ations in all pharmacokinetic parameters were not statistically significant (p> 0.05), and the 90% confidence intervals for the test/reference mean ratios of the plasma pharmacokinetic variabl es lie within the conventional bioequivalence range of 80-125%. Therefore, both formulations were comparable based on the in vitro characterization and were bioequivalent in terms of Cmax and AUC. The two formulations were considered to be bioequivalent