Development of biodegradable polymer coating for colon targeting

Disorders of the colon such as Crohn’s disease, irritable bowel syndrome, ulcerative colitis and colon cancer affect a significant part of the population. These pathologies can often not be treated properly with current pharmaceutical dosage forms. In case of diseases of the large intestine, it is necessary to reach sufficiently high concentrations of the drugs in the colon, which in the case of oral pharmaceutical dosage forms can be highly variable For this reason, in the last decades a large amount of work has been carried out to design colon specific drug delivery systems. pH dependent release systems have been developed successfully, which, however, have given relatively poor results as they depend on the highly variable inter- and intra-subject gastrointestinal tract conditions (pH, transit time, etc.). Undoubtedly, the preferred systems are those that rely on conditions that are only encountered in the colon, as these systems will give true site-specific delivery. In this respect, systems that can be degraded by colonic bacteria are very attractive and promising. Delivery systems based on natural polymers, such as polysaccharides are favourable with respect to safety, but their inherent water solubility is disadvantageous.  Therefore, in this project, biodegradable polymers and blends of biodegradable polymers (e.g. polysaccharides) with non-degradable polymers, capable of film formation, will be developed. Furthermore, for the first time, the relationship between the microstructure of the polymer film and its capacity to be attacked and degraded by colonic bacterial enzymes will be studied. In a second step, selected biodegradable polymer blends will be formulated as biodegradable coatings to deliver model drugs specifically to the colon. The site-specific drug release will be studied during in vitro and in vivo tests.