Preparation and Evaluation of a Suppository Dosage Form Containing Omeprazole

A suppository containing omeprazole was prepared for use as a non-oral dosage form. The stability of omeprazole in different bases, Witepsol H15, Witepsol S55, Witepsol E75 and polyethylene glycol was investigated. Omeprazole was found to be stable only in Witepsol H15. The in-vitro release of omeprazole from Witepsol H15 was good and apparently obeyed a zero-order release pattern. The serum levels of omeprazole after administration of a single dose of the suppository were compared with the enteric formulation in four beagle dogs. The absorption rate from the suppository was significantly more rapid, compared with the commercially available enteric tablet, Omepral. The area under the serum omeprazole level-time curve, after administration of the suppository, was approximately equal to that of the enteric tablet. Similar results were obtained in four healthy volunteers. We conclude that omeprazole, in suppository form suppresses gastric juice secretion as effectively as the commercial enteric tablet. These results suggest that the suppository is an effective dosage form of omeprazole for patients who cannot tolerate oral administration in countries where injectable forms are not available.