Pharmacokinetics of a 5-aminosalicylic acid enteric-coated tablet in patients with Crohn's disease or ulcerative colitis and in healthy volunteers.

An Eudragit-L coated oral 5-aminosalicylic acid (5-ASA; mesalazine) product (Mesasal), has been formulated to deliver 5-ASA to the distal small bowel and colon for the treatment of inflammatory bowel disease. The purpose of this study was to compare the pharmacokinetic profile of this drug between two patient groups, with either inflamed small or large bowel and with volunteers. Two carefully selected patient groups (one with nine patients suffering from Crohn's disease restricted to the small intestine, and one with ten patients suffering from total ulcerative colitis) and a group of ten volunteers received two 250 mg Mesasal tablets in the morning, on a fasting stomach. Plasma 5-ASA and acetyl-5-ASA concentrations were followed for 48 h, and urine and faecal excretion for 72 h. There was a great variation in most pharmacokinetic parameters within each group. Numerically, however, the data suggests a somewhat higher systemic absorption in patients with Crohn's disease than in healthy volunteers or patients with ulcerative colitis. The location of the inflammatory process might have some influence on the pharmacokinetics of 5-ASA in inflammatory bowel disease.