Prosopis gum (PRG) is a hydrophilic polymer that is obtainable from Prosopis africana seed. This research work investigates the use of the gum for duodenum-targeted delivery of omeprazole. Various concentrations of PRG ranging from 5% to 30% were used to formulate omeprazole granules by wet granulation, and the flow properties of the granules were determined. This was followed by compaction of the granules into tablets. The release profiles of the tablets in a pH 1.2 dissolution medium as well as at pH 5.5 were obtained. The formulations were compared with tablets containing 15% hydroxypropyl methylcellulose. Hausner’s ratio of the granules was found to range from 1.05 to 1.17, and Carr’s index ranged from 5.0% to 14.0%. The crushing strength of the test tablets was found to range from 6.2 to 6.9 kgf. Formulations containing 5%, 10%, and 15% PRG showed extensive drug release at the gastric pH, thus allowing only a minimal amount of the drug to get to the targeted site (duodenum), while those containing 20% and 30% of the gum were able to deliver 76% and 82% of the drug, respectively, at the pH that is equivalent to the duodenal site. This work has shown that PRG (extracted from P. africana seeds) used at concentrations of 20–30% is suitable for the formulation of omeprazole tablets to provide a means of targeting the duodenum for the delivery of the drug.
Key words: Duodenum, omeprazole, prosopis gum, targeted-delivery.