DESIGN AND EVALUATION OF COLON SPECIFIC DRUG DELIVERY SYSTEM OF MESALAMINE

As Mesalamine (5ASA) is rapidly absorbed from small intestine, selective delivery of drug to the colon may be regarded as better delivery of drug with fewer side effects and higher efficacy. The aim of the present investigation was to formulate enteric coated sesbania matrix tablets of mesalamine using combined approaches of biodegradable microflora activated systems of sesbania matrix with pH sensitive polymeric coating. FTIR showed no drug polymer interactions. Matrix tablets of mesalamine were prepared by wet granulation with different ratios of sesbania gum. Compressed tablets were prepared and evaluated for uniformity of weight, content of active ingredient, friability, hardness, thickness, in vitro dissolution using paddle method. All formulations showed compliance with Pharmacopoeial standards. Among different batches formulations showed sustained release of drug for 12 hours with and without rat cecal contents in pH 7 were selected. Optimized formulation is coated with different percentages of Eudragit L 100 and Eudragit S 100 as pH sensitive polymers with 5, 10, 15 and 20% weight gain. The results of drug release studies performed using 0.1N HCl for 2 hrs, phosphate buffer pH 6.8 buffer for 3 hours then the medium was replaced with phosphate buffer pH 7.4 containing rat cecal contents. The drug release of tablets coated with Eudragit S 100 with 20% weight gain showed 99.50% due to the microbial enzymatic activity and therefore site specificity of the dosage form consequently sustained the release of the drug over the period of 24 hours. Formulations containing mesalamine, sesbania gum coated with 6% Eudragit S 100 with 20% total weight gain was a promising formulation for the targeted and extended drug delivery to the colon. Keywords: Mesalamine, Sesbania gum, Colon, Eudragit L 100 and Eudragit S 100.