Comparative Bioavailability Study of Two Oral Omeprazole Formulations after Single and Repeated Administrations in Healthy Volunteers

Objective: Two oral enteric-coated pellet formulations of omeprazole, Pepticum® (test formulation) and Mopral® (reference), were administered to 24 healthy volunteers for 5 days at a daily dose of 20mg omeprazole in order to investigate the comparative bioavailability of the two formulations. Results: The data obtained in this study demonstrated the bioequivalence of the two formulations. No statistical differences were observed for the area under the plasma concentration-time curve (AUC 0-t ), the parameter to which the inhibition of acid secretion induced by omeprazole is directly related. Differences observed in maximum plasma drug concentration (C max ) at day 1 for both formulations were not statistically significant. At steady-state, the differences found in C max were associated with a p-value <0.05 with the 90% confidence interval lying between the acceptance range (70 to 140%). Regarding time to reach C max (t max ), p < 0.01 was found both after single and repeated doses. In both cases, Pepticum® showed a delay in reaching C max compared with Mopral®: 2.15 ± 1.11 vs 1.48 ± 0.52h (day 1) and 1.94 ± 0.66 vs 1.31 ± 0.75h (day 5). Conclusion: This study confirmed the reported increases in AUC and C max after repeated administrations, the important intersubject variability and the excellent biological and clinical tolerability of both formulations.