Ilaprazole sodium

Ilaprazole is a substituted benzimidazole prodrug with selective and irreversible proton pump inhibitor activity. A weak base, ilaprazole accumulates in the acidic environment of the secretory canaliculus of the gastric parietal cell where it is converted to an active sulfenamide form that binds to cysteine sulfhydryl groups on the luminal aspect of the proton pump hydrogen-potassium adenosine triphosphatase (H+/K+ ATPase), thereby inhibiting the pump's activity and the parietal cell secretion of H+ ions into the gastric lumen, the final step in gastric acid production. (In Vitro) :On cumulation of 14C-aminopyrine in histamine stimulated parietal cells, the IC50 of Ilaprazole (IY-81149) sodium is 9 nM. (In Vivo) :Ilaprazole sodium (3-30 mg/kg; i.d.) dose-dependently inhibits gastric acid secretion.In anesthetized rats, Ilaprazole sodium dose-dependently increases gastric pH which is lowered by histamine infusion. In the case of i.v. injection, the ED50 of Ilaprazole sodium and Omeprazole is 1.2 and 1.4 mg/kg and in the case of i.d. administration, the ED50 of Ilaprazole sodium and omeprazole is 3.9 and 4.1 mg/kg, respectively. Ilaprazole sodium also significantly inhibits pentagastrin-stimulated gastric secretion. Its ED50 is 2.1 mg/kg and that of Omeprazole was 3.5 mg/kg with i.d. administration. In the case of i.v. injection, Ilaprazole sodium is equipotent to Omeprazole. Ilaprazole sodium also inhibits gastric acid secretion strongly in fistular rats. The ED50 of Ilaprazole sodium administered intraduodenally is 0.43 mg/kg and that of omeprazole Is 0.68 mg/kg.