Formulation and Evaluation of Enteric Coated Delayed Release Tablets of Omeprazole for Duodenal Ulcer

The objective of present study was to develop pharmaceutically elegant and stable enteric coated tabletformulation for highly unstable drug in acidic environment using pH dependent polymers. Omeprazoleis a specific and non-competitive inhibitor of the enzyme H+/K+-ATPase. It is unstable in conditions oflow pH and required protection from the effects of gastric acid when given orally so it is formulated inthe form of enteric coated dosage forms. The core tablets were prepared by direct compression methodusing different concentration of crospovidone as a super disintegrant. Formulations showing lessdisintegration time were first subcoated with HPMC 15 cps upto 3% weight gain, followed by entericcoating with Eudragit L 100, Eudragit L 100-55 and Cellulose acetate phthalate. Pre and postcompression evaluation of core and coated tablets were carried out. In vitro drug release studies wereconducted in acidic and basic media to determine the appropriate coating ratio. All batches entericcoated with 8% weight gain of three polymers showed stable coating in 0.1 N HCl for 2 hours.Formulated batch F11 with 7% weight gain of Eudragit L 100-55 showed stable coating in 0.1 N HCland had shown complete drug release in phosphate buffer pH 6.8. The prepared enteric coated tabletsexhibited good physical and chemical stability, when subjected to accelerated stability studies. Further,when compared to marketed formulation (OPT tablet 20 mg Omeprazole), the prepared enteric coatedtablets showed excellent similarities with marketed product (with respect to drug content, disintegrationtime and drug release) thereby establishing bioequivalence with marketed product.