Development of omeprazole buccal adhesive tablets with stability enhancement in human saliva

To develop an omeprazole buccal adhesive tablet, the absorption of omeprazole solutions from human oral cavity was evaluated and the physicochemical properties such as the bioadhesive forces of various omeprazole tablet formulations composed of bioadhesive polymers and alkali materials, and the stability of omeprazole tablets in human saliva were investigated. About 23% of the administered dose was absorbed from the oral cavity at 15 min after the administration of omeprazole solutions (1 mg/15 ml). A mixture of sodium alginate and HPMC was selected as the bioadhesive additive for the omeprazole tablet. Omeprazole tablets prepared with bioadhesive polymers alone had the bioadhesive forces suitable for buccal adhesive tablets, but the stability of omeprazole in human saliva was not satisfied. Among alkali materials, only magnesium oxide could be an alkali stabilizer for omeprazole buccal adhesive tablets due to its strong waterproofing effect. Two tablets composed of [omeprazole/sodium alginate/HPMC/magnesium oxide (20/24/6/50, mg/tab)] and [(20/30/0/50, mg/tab)] were suitable for omeprazole buccal adhesive tablets which could be attached to human cheeks without collapse and could be stabilized in human saliva for at least 4 h. It was concluded that these two formulae were potential candidates for the subject of further study for the development of omeprazole buccal adhesive tablets.