Abstract: 
In the past ten years, there have been major advancements in medicine formulations that target the colon specifically. If a medicine could be administered directly to the colon, the effectiveness of the treatment might increase. Poorly soluble medications been proven to be absorbed in the colon. Because of their improved therapeutic efficacy and regulated drug release with fewer adverse effects, microspheres have become more important for drug delivery in the colon. This review briefly discusses colon introduction, various colon targeting strategies, and microspheres as a colon medication delivery system carrier.

Keywords: Colon Targeted Drug Delivery System, pH-Sensitive, Time Controlled Release, Microbially Triggered, Prodrug Approach, Microsphere.