Kinase experiment:

About 60 μg enzyme is pre-incubated in a medium consisting of 5 mM imidazole buffer and ilaprazole and omeprazole at concentrations of 0.01, 0.1, 0.5, 1, 5 μM in a final volume of 0.5 mL. Ilaprazole is dissolved in DMSO. All incubations contain less than 1 % DMSO. The enzyme reaction is started by the addition of 0.5 mL of a mixture containing 4 mM MgCl2, 4 mM ATP, and 80 mM imidazole buffer (pH 7.4), with or without 20 mM KCl. After incubation for 15 min at 37 ℃ the reaction is terminated by adding 1 mL of 24 % trichloroacetic acid, and the inorganic phosphorus from the ATP is measured[1].

Animal experiment:

Rats: Rats are treated with 3 mg/kg ilaprazole for 0, 1, 2, 3, 4, 5 and 7 h. 1 h after pylorus ligation, the animals are sacrificed, and the gastric juice is collected and analyzed for acid output. Pentagastrin 60 μg/kg is given intravenously to rats 30 min before the pylorus is ligated[1].

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.