Comparative Bioavailability of Two Oral Formulations of Omeprazole

摘要

Omeprazole is a very widely used proton-pump inhibitor. Currently, there are several branches available in Mexico, however, limited information about their bioavailabilities is available. The purpose of this study was to compare the bioavailability of two of them, Losec~R and Omelcid~R. Twenty-eight healthy volunteers were enrolled in this study that was carried out following the recommendations of the Declaration of Helsinki. Subjects read the protocol that was approved by the institutional research and ethics committees and gave written consent for participation. After an overnight fast, volunteers received an oral dose of 20 mg omeprazole (formulation A or B) and blood samples were obtained at selected times during 8 hours. Plasma was obtained by centrifugation and stored frozen until analyzed by a validated HPLC method. Pharmacokinetic parameters were obtained by non-compartmental analysis and values ((+-) s.e.m.) obtained were as follows: C_max 354.28(+-)51.57 and 308.95(+-)44.42 ng/ml, t_max 2.26(+-)0.22 and 2.63(+-)0.24 h and AUC_8h 701.01(+-)109.34 and 774.13(+-)132.84 ngh/ml for formulations A and B respectively. Log transformed C_max and AUC_8h were compared by analysis of variance and 90% confidence limits of the parameters ratios (B/A) were 72.73-106.34% and 90.32-124.96%, for C_max and AUC_8h respectively. As confidence intervals did not exceed the 70-142.9% limits for C_max and 80-125% for AUC_8h, it is concluded that the formulations tested are bioequivalent.