Pharmaceutic development: mesalazine.
Sulfasalazine is composed of mesalazine and sulfapyridine linked by an azo bond. It has been shown that the clinical activity of sulfasalazine in the treatment of inflammatory bowel disease is derived from the mesalazine moiety, whereas most of the side effects are associated with the sulfapyridine component. To avoid the side effects associated with sulfapyridine, researchers have developed dosage forms that deliver mesalazine to the site of inflammation. The preparations were developed by combining two mesalazine molecules, by joining mesalazine with a carrier molecule that has a low side-effect profile, and by formulating controlled and slow-release mesalazine products. Claversal is a controlled-release product that contains 250 mg or 500 mg of mesalazine plus buffered adjuvants in a tablet core surrounded by a special acrylic polymer. The polymer coating starts to dissolve at pH 6.0, and, as a result, mesalazine is reliably released in the distal small bowel and colon. Thus this product can be useful in the treatment of patients with ulcerative colitis and Crohn's disease.