The objective of following review is to elaborate chitosan microsphere, chitosan is natural polymer used as potential carrier for many drugs and also for many drug delivery such as topical, parenteral, buccal, targeted drug delivery. The colonic drug delivery is highly desirable for local treatment of a variety of bowel diseases such as ulcerative colitis, Crohn's disease, ameabiosis, colonic cancer, and systemic delivery of many drugs which degrades in stomach and small intestine, such as

more »

... ins and peptides. Colon is the distal organ of the GIT, hence difficulty arises in colonic drug delivery. However there are many techniques for colon specific drug delivery namely prodrugs, pH dependent, time dependent, microbially triggered system, pressure controlled, osmotic controlled, multiparticulates system such as microparticle, nanoparticle, pellets etc. Microparticles is preferred over unit dosage form as the system enables the drug to reach colon quickly & retained in it for long period of time. Using different techniques of microparticles targeted drug delivery achieved. Due to this dose of drug and side effects minimizes.