Sustained Delivery of Intact Drug to the Colon: Mesalamine Formulation and Temporal Gastrointestinal Transit Analysis

The goal was to use temporal gastrointestinal transit simulations and formulation to predict and provide sustained input of target-site directed oral drug delivery exclusively into the colon. Using mesalamine as the model drug for formulation coupled with stomach emptying rates (fed and unfed) plus intestinal transit times demonstrates concepts and provides a specific example for treatment in ulcerative colitis. Formulation involved extrusion and spheronization into beads which were then coated with aqueous Eudragit® S. Drug is released only at colonic pH and gastrointestinal transit predicts sustained drug input into the colon, especially when food effects are included.