Lansoprazole is a white to brownish-white odorless crystalline powder which melts with decomposition at approximately 166°C. Lansoprazole is freely soluble in dimethylformamide; soluble in methanol; sparingly soluble in ethanol; slightly soluble in ethyl acetate, dichloromethane and acetonitrile; very slightly soluble in ether; and practically insoluble in hexane and water.
Lansoprazole is an antiulcer drug similar to omeprazole. Like omeprazole, lansoprazole is an acid proton-pump inhibitor. It is used for the short-term treatment of duodenal ulcers or erosive esophagitis, and for long-term treatment of a pathological hypersecretory condition known as Zollinger-Ellison syndrome. Lansoprazole is at least as effective as omeprazole in treating peptic ulcers and reflux esophagitis, and it has been shown to relieve reflux symptoms more quickly than either omeprazole or ranitidine. Lansoprazole inhibits gastric acid secretion. It belongs to a new class of antisecretory agents, the substituted benzimidazoles, which suppress gastric acid secretion by inhibiting the H+/K+ ATPase enzyme system of gastric parietal cells. A significant increase in gastric pH and decrease in basal acid output follow oral administration of lansoprazole. In hypersecretory conditions, lansoprazole has a marked effect on gastric acid secretion, both basal-and pentagastrin-stimulated.
Lansoprazole decreases the amount of acid produced in the stomach. Due to its mechanism of action, lansoprazole reduces gastric acid secretion whatever the nature of the stimulation. Lansoprazole causes rapid, effective and lasting inhibition of gastric acid secretion. This inhibition is dose-dependent. Gastric secretory functions recover gradually after the end of treatment. Lansoprazole has no effect on histamine, acetylcholine and gastrin receptors. Lansoprazole is used to treat and prevent stomach and intestinal ulcers, erosive esophagitis (damage to the esophagus from stomach acid), and other conditions involving excessive stomach acid such as Zollinger-Ellison syndrome.