I n Vivo Evaluation of 5-ASA Colon-Specific Tablets Using Experimental-Induced Colitis Rat Animal Model

Colonic drug delivery is intended not only for local treatment in inflammatory bowel disease (IBD) but also for systemic delivery of therapeutics. Intestinal myeloperoxidase (MPO) determination could be used to estimate the average level of inflammation in colon as well as to determine the efficacy of drugs to be used in the treatment of inflammatory bowel diseases or study the specificity of dosage forms to be used for colonic targeting of anti-inflammatory drugs. Colonic prodrug sulfasalazine (SASP) gets metabolized to give 5-aminosalicylic acid (5-ASA), which is the active portion of SASP. However, when given orally, 5-ASA is absorbed in upper part of gastrointestinal tract (GIT) and not made available in colon. In the present study, colon-targeted delivery of 5-ASA was achieved by formulating tablets with two natural polymers namely guar gum and pectin using compression coating method. Colonic specificity of 5-ASA tablets (prepared using guar gum and pectin as polymers) was evaluated in vitro using simulated fluids mimicking in vivo environment as well as in vivo method using chemically (2,4,6-trinitrobenzenesulfonic acid and acetic acid)-induced colitis rat model. Both colon-specific formulations of 5-ASA (guar gum and pectin) were observed to be more effective in reducing inflammation in chemically induced colitis rat models when compared to colon-specific prodrug sulfasalazine as well as conventional 5-ASA administered orally.KEY WORDS: colitis, colon-specific drug delivery, myeloperoxidase