Pharmacokinetic properties of various preparations of 5-aminosalicylic acid (5-ASA) and budesonide

Different orally and rectally applicable forms of 5-ASA and budesonide have been developed to achieve sufficient high concentrations of the active moi eties at the site of inflammation (small and/or large bowel) and to limit t he systemic action of the drugs. This concept of drug targeting could be ac complished by both special galenic formulations and by utilizing the pharma cokinetic properties of the agents especially their high intestinal and hep atic presystemic elimination. Thus, 5-ASA and budesonide represent drugs of first choice in the treatment of Crohn's disease and ulcerative colitis. This review describes the various pharmacokinetic and (patho)physiologic fa ctors and their impact on drug delivery and biological availability of the different 5-ASA and budesonide preparations.