Target-specific drug release to the colon

Abstract
The ability to deliver drugs to the human colon in a specific manner has become feasible over the years. Targeting pharmaceutical drugs to the colon makes it possible to achieve local or systemic drug delivery to this site. To deliver the compounds in a non-degraded form to the lower part of the gastrointestinal tract, they must first pass through the stomach and the upper part of the intestine before releasing the contents in the colon. This review provides an overview of the various approaches to targeted drug delivery to the colon using different drug delivery systems, their limitations and the future developments in this field. A microbially controlled system, which is a well-accepted approach, based on natural polymers, has the greatest potential for colonic delivery, particularly in terms of site specificity and safety. However, close attention should be paid to the performance of these products in the heterogeneous environment of the human gastrointestinal tract.