5-Aminosalicylic acid derivatives. Clinical and pharmaceutical evaluation.

: Several new 5-aminosalicylic acid (5-ASA) derivatives have been introduced for the treatment of chronic inflammatory bowel disease (CIBD). In azo-bond preparations, 5-ASA is linked to an inert carrier (Balsalazide) or to another 5-ASA molecule (Dipentum). The pharmacokinetic profile is similar to salazosulphapyridine (SASP) and the preparations are as effective as SASP in treatment of ulcerative colitis (UC) and with fewer side effects. In controlled release preparations (Asacol, Pentasa, Salofalk), 5-ASA is coated with compounds resistant to low pH, but which deliver 5-ASA to the intestines at various rates at higher pH values. The drugs are as effective as SASP in maintenance of remission and in the treatment of mild to moderate flare ups in UC. A larger systemic absorption is found for the three preparations compared to SASP. The controlled release preparations seem promising in the treatment of Crohn's disease, but further studies are needed. The controlled release preparations should be the drugs of choice in patients with UC allergic to or intolerant of SASP and to males who wish to have children.