Targeting drugs to the colon is one of the modern research 
areas in pharmaceutical sciences at the deciding time, place 
and exact amount, and improving patient flexibility, 
compliance and bioavailability. To reach doing well colon 
targeted drug delivery, a drug necessitate to be protected 
from degradation, release and absorption in the upper part 
of the GI tract and then to be ensure abrupt or controlled 
release in the proximal colon. The colon is a site wherever 
both local and systemic delivery of drugs can take place. 
Local delivery allows topical treatment of inflammatory 
disease
 like 
constipation,
 chronic
 pancreatitis, 
pacreatactomy and colonic cancer etc. However, treatment 
can be made useful if the drugs be able to target directly 
into the colon; thereby reducing the systemic side effect 
and improve drug therapy or bioavailability in the upper GI 
tract. This article also discuss different country patent and 
approach like prodrugs, pH dependent, time dependent, 
azo-hydrogels,
 pressure controlled,
 pulsatile and 
microbially triggered drug delivery system, and evaluation 
for site specific drug delivery to colon. This overview 
focused on more than 100 patents available in different 
colonic drug delivery on current days. It is demanding 
areas for future investigate and hold plenty of promise for 
novel and efficient approach for targeted drug delivery 
system.