Pharmacokinetics and Bioequivalence Study of Two Proton Pump Inhibitor Products

Omeprazole (OPZ) efficiently suppresses acid secretion in the parietal cells of the stomach. It is widely recommended as proton pump inhibitor (PPI) in Egypt. Presence of many products containing omeprazole available in the Egyptian market raises questions of generic substitution and/or therapeutic equivalence. The aim of the study was to compare the pharmacokinetic parameters and relative bioequivalence properties of two oral omeprazole formulations, Gastroloc® and Pepzol® enteric coated capsules, in healthy subjects. A randomized, two-way crossover study was conducted to study the pharmacokinetic parameters of the OPZ products in 24 healthy human volunteers in compliance with the Declaration of Helsinki and ICH guidelines. After oral administration and at specified time intervals, blood samples were collected and analyzed for plasma OPZ content using a validated HPLC method. The Pharmacokinetic parameters such as AUC0-12, Cmax, Tmax, t1/2 and elimination rate constant were determined from plasma concentration-time profile for both formulations by a non-compartmental method. The statistical analysis of the data obtained in this study showed no significant difference between the tested OPZ products. The results indicated that the tested products have similar bioavailability profiles and therefore can be considered bioequivalent based on the obtained data of AUC, Cmax, and Tmax.