Lansoprazole is a Benzimidazole sulfoxide derivative that produces long lasting inhibition of gastric acid secretion by blocking H+-K+ATPase enzyme (the proton pump) of gastric parietal cell. Lansoprazole is rapidly and extensively absorbed from gastrointestinal tract when administered as enteric coated pellets. There is little or no presystemic metabolism. Absolute bioavailability of Lansoprazole from this form is 85% in healthy volunteers. Lansoprazole is rapidly distributed throughout the body, with a small volume of distribution becasuse it is almost completely bound to plasma protein. Lansoprazole is eliminated primarily by hepatic metabolism, the metabolite being excreted both via bile and in urine.
