Objective: Taking Chinese compound medicine Yuchangning as a research model,prepared the pH and time dependent Yuchangning tablets for colon-specific delivery(PT-YT-CSD),and evaluated the releasing property in vitro.

Objective To prepare the pH-dependent Yuchangning Tablet for colon-specific delivery(PYTCSD) used in treating the ulcerative colitis and evaluating the releasing property in vivo and in vitro.

Objective: Taking Chinese compound medicine Changkangning as a research model,prepared the pH and enzymes de-pendent Changkangning tablets for colon-specific delivery(PE-CT-CSD),through the research on trundale coating conditions.

Preparation of Kangfuxin colon targeting micro-pellets;

In vivo/in vitro evaluation of Kangfuxin colon targeting capsules;

Conclusions: This research provided a way for traditional Chinese drug preparation of colon targeting.

In this article , a review of research in the colon specific drug delivery based on azo polymers in which azo groups are located in the main chain, cross links, or in branches, is given.

Azo polymers may be expected as colon specific drug delivery systems because azo bonds in polymers can be reduced by azoreductase generated by colonic bacteria.