Inulin, a Natural Plant Polysaccharide, as a Vehicle for Delivery of Colon Cancer Drugs

Controlled drug delivery occurs when a polymer, whether natural or synthetic, is judiciously combined with a drug or other active agent in such a way that the active agent is released from the material in a predesigned manner. The release of the active agent may be constant over a long period, it may be cyclic over a long period, or it may be triggered by the environment or other external events. In any case, the purpose behind controlling the drug delivery is to achieve more effective therapies while eliminating the potential for both underand overdosing. Other advantages of using controlled-delivery systems can include the maintenance of drug levels within a desired range, the need for fewer administrations, optimal use of the drug in question, and increased patient compliance. While these advantages can be significant, the potential disadvantages cannot be ignored: the possible toxicity or nonbiocompatibility of the materials used, undesirable by-products of degradation, any surgery required to implant or remove the system, the chance of patient discomfort from the delivery device, and the higher cost of controlled-release systems compared with traditional pharmaceutical formulations. Inulin is a naturally occurring polysaccharide found in many plants. It consists of β 2-1 linked Dfructose molecules having a glucosyl unit at the reducing end. Various inulin and dextran hydrogels have been developed that serve as potential carrier for introduction of drugs into the colon. Colon cancers are difficult to treat because oral administrated drugs are absorbed at the stomach and intestine levels and they do not reach colon; in addition, intravenous administrated drugs are eliminated from the body before reaching colon. Because inulin is not absorbed in the stomach or in the intestine, and inulin is degraded by colonic bacteria, drugs encapsulated in inulin-coated vesicles could be specifically liberated in the colon. Therefore, the use of inulin-coated vesicles could represent an advance for colon cancer treatment. Here, we study the use of inulin, from different sources (chicory, artichoke, and Jerusalem artichoke), as a vehicle for the controlled delivery of colonic drugs. The encapsulation of several antitumoral drugs in inulin vesicles and their release and activity was studied in several colon cancer cells in cultures. An optimization study for the synthesis of inulin vesicles and drug release by inulinase is presented.