Capacity-limited gut wall metabolism of 5-aminosalicylic acid, a therapeutically active metabolite of sulfasalazine, in rats.
The metabolic fate of 5-aminosalicylic acid (reported to be the active therapeutic moiety of sulfasalazine) was assessed in fasting rats as a function of dose (25-200 mg/kg) and administration route (oral, intraperitoneal, and intravenous). 5-Aminosalicylic acid is subject to both capacity-limited presystemic (apparently during first passage through the intestinal epithelium) and systemic acetylation. The possibility exists that 5-aminosalicylic acid also is acetylated presystemically after oral sulfasalazine administration to patients with inflammatory bowel disease. Any alteration in the absorption activity if N-acetyl-5-aminosalicylic acid is inactive or less active than 5-amino-salicylic acid.
D000107:Acetylation; D000284:Administration, Oral; D000636:Aminosalicylic Acids / Q000378:metabolism*; D000818:Animals; D001711:Biotransformation; D004305:Dose-Response Relationship, Drug; D007274:Injections, Intraperitoneal; D007275:Injections, Intravenous; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D051381:Rats; D012460:Sulfasalazine / Q000008:administration & dosage / Q000378:metabolism*
D000636:Aminosalicylic Acids; D012460:Sulfasalazine