Omeprazole is a selective and irreversible inhibitor of the gastric H+/K+ ATPase pump (IC50 = 1.1 μM).1 It is a racemic mixture of two enantiomers, (S)-omeprazole and (R)-omeprazole , which are prodrugs of the active sulfonamide formed by acid-stimulated conversion.2,3 Both enantiomers are extensively metabolized by the cytochrome P450 (CYP) isomers CYP2C19 and CYP3A4.3
1.Smolka, A.J., Goldenring, J.R., Gupta, S., et al.Inhibition of gastric H,K-ATPase activity and gastric epithelial cell IL-8 secretion by the pyrrolizine derivative ML 3000BMC Gastroenterol.4(4)(2004) 2.Richardson, P., Hawkey, C.J., and Stack, W.A.Proton pump inhibitors. Pharmacology and rationale for use in gastrointestinal disordersDrugs56(3)307-335(1998) 3.Shi, S., and Klotz, U.Proton pump inhibitors: An update of their clinical use and pharmacokineticsEur. J. Clin. Pharmacol.64(10)935-951(2008)