The active ingredient in Omeprazole Enteric-Coated Capsules is asubstituted benzimidazole, 5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl]-1Hbenzimidazole, acompound that inhibits gastric acid secretion. Its empiricalformula is C17H19N3O3S, with a molecular weight of 345.42.Omeprazole is a white to off-white crystalline powder which meltswith decomposition at about 155°C. It is a weak base, freelysoluble in ethanol and methanol, and slightly soluble in acetoneand isopropanol and very lightly soluble in water. The stability ofomeprazole is a function of pH; it is rapidly degraded in acidmedia, but has acceptable stability under alkaline conditions.Omeprazole Enteric-Coated Capsules is supplied as delayed-releasecapsules for oral administration. Each delayed-release capsulecontains 20 mg of omeprazole in the form of enteric-coatedgranules.