Colon Drug Targeting: Overview on Physico-Chemical Aspects

Numerous local diseases including ulcerative colitis, Crohn's disease, irritable bowel syndrome, chronic pancreatitis and colon cancer are able to manage using targeting of drugs to colon specific region using colon targeted drug delivery systems as per reports. Drugs derived from newer technology proteins and peptide types and conventional types are also explored to be used as potential candidates for targeting to colonic region via oral route. These drug targeting is aimed for obtaining local, topical and/or systemic absorptions for possible management of colon diseases. Few other drug(s) that are degraded into upper gastrointestinal tract due to reasons for acidic and enzymatic assaults are also used to target into colonic region through oral routes of administration. The intended formulation strategies and mechanisms are developed during past few decades for specifically targeting to colon in order to obtain possible beneficial therapeutic effects. This article argued in detail for those reported developed colonic formulations gets that were affected with numerous gastrointestinal physico-chemical factors viz., the pH gradients (acidic and alkaline) throughout the gastrointestinal tract, transit time variations, presence of microbial floras and enzymes, peristalsis movements, absorption criteria etc. Those arguments also includes other numerous aspects viz., merits and limitations, factors affecting delivery systems, criteria for drug selection, drug candidates, targeting approaches and local colonic diseases for successful drug targeting to colon region.