Abstract

ESOMEPRAZOLE: S-ISOMER OF OMEPRAZOLE WITH PROFOUND GASTRIC ACID SECRETION INHIBITORY ACTON

Eby George* and Sumayya Navas

ABSTRACT

Esomeprazole was the first discovered single isomeric proton pump inhibitor having bioavailability greater than Omeprazole providing profound inhibition of gastric acid secretion. Esomeprazole is a proton pump inhibitor used in the treatment gastroesophageal reflux disease and zollinger Ellison syndrome. The Plasma concentrations after oral administration of esomeprazole have confirmed that the metabolism of esomeprazole results in increased delivery to the systemic circulation as compared to an equavalent dose of omeprazole. The total body Clarence of Esomeprazole was three times lower than Omeprazole (R form). The first pass effect of S isomer was reduced and total clearance was increased resulting in high plasma levels. The crossover study using 15mg dose Esomeprazole and Omeprazole in human volunteers shown that area under the curve for Esomeprazole was almost 4 times to that of Omeprazole. Crossover study using 20mg Esomeprazole, resulted in almost 70 % higher value than Omeprazole when given for 5 days once daily. Esomeprazole gets rapidly converted into sulfonamide at pH 1 which specifically binds to proton pump and inhibits it through inactive covalent bond formation between the reactive sulphur atom of the sulphonamide. The effectiveness of PPI’S in healing erosive eosophagitis confirmed the superiority of 40mg Esomeprazole oral administration daily. Many approaches are taken into account to accomplish this which involves floating tablets, matrix tablets and mucoadhesive tablets.

Keywords: Esomeprazole, gastroesophageal reflux disease, zollinger Ellison syndrome, omeprazole.