Primary and Novel Approaches in Colon Targeted Drug Delivery System: A Review

Targeted drug delivery into the colon is highly desirable for local treatment of a variety of bowel diseases such as ulcerative colitis, Crohn’s disease, amoeabiasis , colonic cancer, local treatment of colonic pathologies, and systemic delivery of protein and peptide drugs. Colonic delivery refers to targeted delivery of drugs into the lower GI tract, which occurs primarily in the large intestine (i.e. colon). The colon specific drug delivery system (CDDS) should be capable of protecting the drug en route to the colon i.e. drug release and absorption should not occur in the stomach as well as the small intestine, and neither the bioactive agent should be degraded in either of the dissolution sites but only released and absorbed once the system reaches the colon. Different approaches are designed based on prodrug formulation, pHsensitivity, time-dependency (lag time), microbial degradation and osmotic pressure etc to formulate the different dosage forms like tablets, capsules, multiparticulates, microspheres, liposomes for colon targeting. The efficiency of drug delivery system is evaluated using different in vitro and in vivo release studies. This review article discusses, in brief, introduction to targeted drug delivery system, anatomy and physiology of the colon and approaches utilized in the colon targeted drug delivery system.