Abstract: 
Colon specific drug delivery has gained increased importance not just for delivery of drug for the treatment of local diseases, associated with the colon but also potential site for systemic delivery of therapeutic drug. Treatment could be more effective if it is possible for drug to be directly delivered to colon. This article gives an overview on anatomy and physiology of the colon and approaches utilized for colon specific drug delivery. This article also discusses advantages and limitations of the different approaches and also deals with the microsphere, various methods used for preparations of microspheres and advantages and disadvantages of microspheres.

Keywords: Microspheres, Controlled Release, Novel Drug Delivery, Approaches of Colon Targeting.