Vonoprazan Fumarate

Vonoprazan Fumurate, a novel potassium-competitive acid blocker, inhibits gastric acid secretion. Vonoprazan Fumurate inhibited H+, K+-ATPase activity in porcine gastric microsomes with IC50 value of 19 nM at pH 6.5. (In Vitro) :The inhibitory activity of Vonoprazan Fumurate was unaffected by ambient pH. The inhibition by Vonoprazan Fumurate was reversible and achieved in a K (+) -competitive manner, quite different from that by lansoprazole. Vonoprazan Fumurate exhibits porcine gastric H+ , K+-ATPase activity in a concentration-dependent manner. (In Vivo) :Vonoprazan Fumurate, at a dose of 4 mg/kg (as the free base) orally, completely inhibited basal and 2-deoxy-d-glucose-stimulated gastric acid secretion in rats, and its effect on both was stronger than that of lansoprazole. Vonoprazan Fumurate increased the pH of gastric perfusate to a higher value than did lansoprazole or SCH28080, and the effect of Vonoprazan Fumurate was sustained longer than that of lansoprazole or SCH28080.