Ilaprazole (IY-81149) sodium is an orally active proton pump inhibitor. Ilaprazole sodium irreversibly inhibits H +/K +-ATPase in a dose-dependent manner with an IC50 of 6 μM in rabbit parietal cell preparation. Ilaprazole sodium is used for the research of gastric ulcers. Ilaprazole sodium is also a potent TOPK (T-lymphokine-activated killer cell-originated protein kinase) inhibitor.