Colon specific delivery using ethylcellulose and chitosan in a compression coated tablet

Ethylcellulose and chitosan are used for colon specific delivery in a compression coated tablet prepared by direct compression method. Three types of chitosan are used and three levels of chitosan are studied. Caffeine was used as a model drug in this study. The influence of chitosan type and level on the hardness, friability and drug release were studied. There was no influence of the type of chitosan and level of chitosan on hardness and friability. Drug release occurred primarily due to the opening of the coat, with subsequent drug dissolution and diffusion from the core tablet. Chitosan types have no effect on the release in simulated intestinal fluid, while the level of chitosan modified the release. The chitosan level also influenced the release in presence of rat cecal and colonic enzymes. An enteric coat is needed to protect the tablet from the gastric environment.