Author(s): Pramod Kumar Biswal*, Anant Kumar and Anupam Singh Bhadouriya
Due to greater flexibility in design of dosage form and high patient compatibility, oral administration of different dosage forms is the most commonly used method.But the gastrointestinal tract presents several formidable barriers to drug delivery. In oral colon-specific drug delivery system, colon has a large amount of lymphoma tissue which facilitates direct absorption in to the blood, negligible brush boarder membrane activity, and much less pancreatic enzymatic activity as compared with the small intestine. Colon-specific drug delivery has gained increased importance not just for the delivery of the drugs for treatment of local diseases associated with the colon but also for its potential for the delivery of proteins and therapeutic peptides. Different approaches are designed based on pro-drug formulation, pH-sensitivity, time-dependency (lag time), microbial degradation and osmotic pressure etc. to formulate the different dosage forms like tablets, capsules, multi-particulates, microspheres, liposomes for colon targeting. The efficiency of drug delivery system is evaluated using different in vitro and in vivo release studies. This review updated the research on different approaches for formulation and evaluation of colon-specific drug delivery systems (CDDS).