A Comparative Dissolution Kinetics Test for Omeprazole-Containing Medicines, Reproducing Secretory and Motor-Evacuatory Impairments the Stomach of Patients with Acid-Dependent Diseases

A comparative dissolution kinetics test was used to study the release (dissolution kinetics) of an original and 10 generic formulations of omeprazole from different manufacturers in a medium simulating the moderately acidic conditions in the stomach typical of the state of medication-induced suppression of acidity; tests were also performed in a model of pathological duodenogastric reflux. HPLC was used to measure omeprazole concentrations in aliquots collected at 4, 10, 15, 20, 30, 45, and 60 min in solution with pH 7.0 ± 0.05 after 2 h of exposure at pH 1.2 ± 0.05 or 4.0 ± 0.05. The duration of action of pathological duodenogastric reflux on the therapeutic formulations of omeprazole was 4 min. Not all the study formulations could be completely recognized as equivalents to the original formulation in the in vitro test conditions.