Description

Targeted drug delivery into the colon is highly desirable for local treatment of a variety of
bowel diseases such as ulcerative colitis, Crohn’s disease, amebiosis, colonic cancer, local
treatment of colonic pathologies, and systemic delivery of protein and peptide drugs
(Amidon et al., 2015).

 The colon specific drug delivery system (CDDS) should be capable of protecting the drug en
route to the colon i.e. drug release and absorption should not occur in the stomach as well as
the small intestine, and neither the bioactive agent should be degraded in either of the
dissolution sites but only released and absorbed once the system reaches the colon (Patel et
al., 2014).
The colon is believed to be a suitable absorption site for peptides and protein drugs for the
following reasons; (i) less diversity, and intensity of digestive enzymes, (ii) comparative
proteolytic activity of colon mucosa is much less than that observed in the small intestine,
thus CDDS protects peptide drugs from hydrolysis, and enzymatic degradation in duodenum
and jejunum, and eventually releases the drug into ileum or colon which leads to greater
systemic bioavailability. finally, because the colon has a long residence time which is up to 5
days and is highly responsive to absorption enhancers (Prathap et al., 2014).