Description

The oral administration is the most convenient and commonly used method for drug delivery. Traditionally, solid oral dosage forms have been designed to release their drug load in the upper region of the gastrointestinal tract, where conditions are more suited to drug dissolutions and absorptions. Recently, greater emphasis has been placed on controlling site of drug release from oral formulations for the purposes of improving patient compliance and treatment efficiency . Many protein and peptide drugs like insulin cannot be administered through the oral route because of their degradation by the digestive enzymes of the stomach and the small intestine. Colon-specific drug delivery systems offer several potential therapeutic advantages.The opportunity to reduce adverse effects in the treatment of colonic diseases like, ulcerative colitis, colorectal cancer, Chorn's diseases and amoebiasis by topical application of drugs, active at the mucosal level The elucidation of the mode of action of some nonsteroidal anti-inflammatory drugs (NSAIDs) such as sulindac (metabolized in the colon to the active moiety, sulindac sulfide) that were found to interfere with the proliferation of co