Retention and transit of intestinal mucoadhesive films in rat small intestine

The retention and transit characteristics of intestinal mucoadhesive film s ystems have been studied after intraduodenal administration in rats. Small size four layered film preparations, 0.5 x 0.5 mm, were prepared, where the backing layer (45.1 +/- 2.9 mum thick) was made of a water-insoluble polym er, ethylcellulose (EC), the surface layer was made of enteric pH-sensitive polymers, Eudragit (R) L100, SIN or HP-55 (R) and the middle layer was mad e of cellulose membrane. The surface layer was attached to the middle layer with an adhesive layer composed of carboxyvinyl polymer (Hiviswako (R) 103 ). After administration of ten films to the duodenum, the rats were sacrifi ced hourly and the distribution of the films in the whole small intestine w as directly observed after abdominal incision. The HP-55, Eudragit L100 and S100 film systems were found to adhere to the upper, middle and lower part of the small intestine after 1, 2 and 4 h, respectively, for 2-3 h. Direct inspection study suggests that intestinal mucoadhesive film system has fun ctions of. (1) pH-dependent intestinal adhesion site specificity; (2) adhes ion to the intestinal wall; and (3) retention in the small intestinal adhes ion site for at least 2 h. Intestinal mucoadhesive film system has been sug gested to be a targeting system for drugs to the gastrointestinal tract. (C ) 2001 Elsevier Science B.V. All rights reserved.