Colon Targeted Drug Delivery System
The colon is a site where both local and systemic delivery of drugs can take place. Colonic drug delivery has gained increased importance not just for the delivery of the drugs for the treatment of local diseases associated with the colon like Crohn’s disease, ulcerative colitis, etc. but also for the systemic delivery of proteins, therapeutic peptides, anti-asthmatic drugs, antihypertensive drugs and anti-diabetic agents. To achieve successful colon targeted drug delivery, a drug need to be protected from degradation, release and absorption in the upper portion of the GI tract and then to be ensured abrupt or controlled release in the proximal colon. This review mainly compares the primary approaches for CDDS (Colon Specific Drug Delivery) namely prodrugs, pH and time dependent systems, and microbial triggered systems, which achieved limited success and had limitations as compared with newer CDDS namely pressure controlled colonic delivery capsules, CODESTM, and osmotic controlled drug delivery (ORDS-CT) which are unique in terms of achieving in vivo site specificity, and feasibility of manufacturing process. Treatment could be more effective if it is possible for drug to be directly delivered to colon. This article also discusses advantages & limitations of the different approaches & evaluation for site specific drug delivery to colon.