(R)-Lansoprazole (T 168390) is the R-isomer of lansoprazole and a substituted benzimidazole prodrug with selective and irreversible proton pump inhibitor activity.Lansoprazole (AG 1749) is a potent brain penetrant neutral sphingomyelinase (N-SMase) inhibitor (exosome inhibitor)

Dexlansoprazole, constitutes >80% of circulating drug after oral administration of lansoprazole, provides lower clearance and 5-fold greater systemic exposure than the S-enantiomer following oral administration of lansoprazole. Dexlansoprazole MR is a modified release formulation of dexlansoprazole, which employs a novel Dual Delayed Release (DDR) technology that delivers the drug in two discrete phases of release, thereby inhibiting newly activated proton pumps that turn over following initial PPI inactivation of H+,K+-ATPase. Dexlansoprazole MR maintains plasma drug concentrations above the threshold level longer than lansoprazole at all doses, resulting in an optimized drug exposure-intragastric pH relationship. [1] Dexlansoprazole selectively suppresses gastric acid secretion by direct inhibition of the H+K+-ATPase proton pump in the gastric parietal cell, inhibition of this cell membrane enzyme ultimately blocks the final step in acid production. [2]