RELATIVE BIOAVAILABILITY OF OMEPRAZOLE CAPSULES AFTER ORAL DOSING

Abstract

Omeprazole, a proton pump inhibitor, effectively suppresses the gastric acid secretion in the parietal cells of stomach. Pharmacokinetics and relative bioavailability of generic products of omeprazole were compared with innovator product, Losec. Twelve healthy adult volunteers participated in the study which was conducted according to a randomized, open-label single dose Latin square cross over design. The preparations were compared using area under the plasma concentration – time curve (AUC), peak plasma concentration (Cmax), and time to reach peak plasma concentration (tmax). The two generic capsules proved to be bioequivalent with brand-name omeprazole with regard to the pharmacokinetic parameters Cmax, AUC0-t, AUC0-inf and tmax. Moreover the parametric confidence intervals (90%) for the ratio of the Cmax, AUC0-8 and AUC0-∞ values lie between 0.8-1.2. The test formulations were found bioequivalent to the reference formulation by the one-way ANOVA test procedure. On the basis of these results, the 3 formulations were considered to be bioequivalent. Two subjects demonstrated increase in AUCs and high Cmax after administration of either product which may attribute to the ethnic disposition of omeprazole in these subjects.