Ilaprazole (IY-81149) (Synonyms: (R,S)-Ilaprazole, IY-81149)

Ilaprazole (IY-81149) is a proton pump inhibitor; inhibits H+/K+-ATPase with an IC50 of 6.0 μM.

In rabbit parietal cells, ilaprazole irreversibly inhibits H+/K+-ATPase in dose-dependent manner with an IC50 of pump inhibitory activity of 6.0 μM. The IC50 of ilaprazole is 9.0 nM on cumulation of 14C-aminopyrine in histamine stimulated parietal cells[1].

In pylorus-ligated rats, ilaprazole shows strong inhibitory activity against gastric acid secretion. The ED50 of ilaprazole administered intraduodenally is 1.6 mg/kg. For oral administration, the ED50 of ilaprazole is 1.94 mg/kg. Ilaprazole also significantly inhibits pentagastrin-stimulated gastric secretion. Its ED50 is 2.1 mg/kg. In Heidenhain pouch dogs, the acid output is completely blocked at 0.3 mg/kg, 135 min after i.v. administration[1]. Intravenous ilaprazole exhibits high antiulcer activity in a dose-dependent manner. Ilaprazole at a dose of 3 mg/kg decreases ulcer number and index to the same extent as 20 mg/kg esomeprazole. Moreover, the potency of intravenous ilaprazole is superior to that of intragastric ilaprazole. In anesthetized rats, the inhibitory effect of intravenous ilaprazole on histamine-induced acid secretion is faster and longer-lasting than that of intraduodenal ilaprazole[2].

[1]. Kwon D, et al. Effects of IY-81149, a newly developed proton pump inhibitor, on gastric acid secretion in vitro and in vivo. Arzneimittelforschung. 2001;51(3):204-13. [2]. Yu G, et al. Intravenous ilaprazole is more potent than oral ilaprazole against gastric lesions in rats. Dig Dis Sci. 2014 Oct;59(10):2417-22.