Advances of new excipients and technique in colon-specific preparations

The oral colon-specific drug delivery system(OCDDS)has gained more attention from investigators in recent years since it can increase local drug concentration and reduce dosage and side effects. The type of colon-specific drug delivery system consists of enzyme dependent, pH dependent, time dependent, pressure dependent system and CODEDS^TM. The development of many new materials and technology is very important for the preparation of new type of precise positioning colon-specific preparation. This article summarizes the advances in excipients and technique for oral colon-specific drug delivery system in recent years. It may provide a reference and a basis for the researchers concerned.