Abstract

Background: The aim of the present study was to design and characterize the enteric coated mucoadhesive microcapsules of esomeprazole magnesium by solvent evaporation technique using drug, ethylcellulose and mucoadhesive polymer of 1:1:1 ratio for improving the mean gastric residence time and oral bioavailability of the drug. Methods: Characterization of the mucoadhesive microcapsules through FT-IR, and DSC studies showed lack of any significant interactions among drug and polymers, followed by complete encapsulation of the drug in the prepared formulation. Scanning electron microscopy indicated spherical morphology of the prepared formulation with intact nature of the outer coat. Results: This system remains in close contact with the absorption tissue and the mucous membrane, releasing the drug at the action site leading to enhancement in the oral bioavailability due to avoidance of hepatic first-pass metabolism. Physiological variables (i.e., mucin turnover from the mucus layer) plays major role in the estimation of mucoadhesive strength of formulation, by mucin turnover ensures significant amount of soluble mucin available for interaction with mucoadhesive polymer. Conclusion: The selected optimum formulation (F3c) identified from the current studies protected rat stomach ulcer induced by ethanol vis-à-vis the aqueous solution of the drug owing to optimum mucoadhesion, swelling and sustain drug release characteristics by prolonging the duration of action of the drug. Stability studies as per the ICH guidelines showed no significant alteration in drug content and release characteristics indicating stable nature of the optimized microcapsule formulation.

Keywords: Gastric resistance, in vitro release profile, in vitro wash-off test, in vivo anti-ulcer activity, swelling index.