ORAL DELAYED-RELEASE SYSTEM FOR COLONIC SPECIFIC DELIVERY

The paper describes a novel oral time-based drug release system for co lonic specific delivery. The system, designed to exploit the relativel y constant small intestine transit time of dosage forms, consists of d rug-containing cores coated with three polymeric layers. The outer lay er dissolves at pH > 5, then the intermediate swellable layer, made of high-viscosity HPMC, interacts slowly with aqueous fluids, thus provi ding the delay phase. The inner film is made of an enteric material. T he system provides the expected delayed release pattern, as also indic ated by the preliminary in vivo experiments on rats.