Delayed‐release mesalazine (5‐aminosalicylic acid): coat dissolution and excretion in ileostomy subjects.

Abstract

1. Delayed-release mesalazine has been formulated to deliver 5-aminosalicylic acid to the colon. We have therefore studied the ileostomy excretion and coat dissolution of this preparation. 2. Following ingestion of a single tablet 88% (range 69-114%) of the 400 mg dose appeared unchanged in the ileosomy effluent over the subsequent 12 h. 3. Ileostomy effluent pH appeared to be a major determinant of 5-aminosalicylic acid release. 4. In vitro studies revealed rapid coat dissolution above pH 7.0, slow dissolution between pH 6.0 and 7.0 and non-dissolution at pH 2.0 and 4.0.