BIOAVAILABILITY OF 5-AMINOSALICYLIC ACID FROM SLOW-RELEASE 5-AMINOSALICYLIC ACID DRUG AND SULFASALAZINE IN NORMAL-CHILDREN

The bioavailability of a controlled release 5-aminosalicylic acid prep aration (Pentasa) was investigated in nine healthy children after a me dication period of six days (1000 mg/day) and compared with sulfasalaz ine (Salazopyrin) (2000 mg/day). The local bioavailability in the dist al gut lumen, reflected by the 5-aminosalicylic acid concentration in the fecal water, showed comparable values after Pentasa (4.44 mmol/lit er) and Salazopyrin (6.25 mmol/liter). The concentration of N-acetyl-5 -ASA was significantly higher after Pentasa, reflecting the more proxi mal release of 5-aminosalicylic acid compared with Salazopyrin. No rel ation was found between the 5-aminosalicylic acid fecal water concentr ation and the 5-aminosalicylic acid dose per kilogram of body weight. The urinary excretion of 5-aminosalicylic acid and N-acetyl-5-aminosal icylic acid was higher after Pentasa than after Salazopyrin (32% vs 25 %). Dose interval plasma concentration curves showed low values after both preparations. Based on the concept that the fecal water concentra tion is decisive for the efficacy of 5-aminosalicylic acid in distal i nflammatory bowel disease, Pentasa treatment offers a relevant alterna tive in cases of Salazopyrin intolerance or allergy in children. The h igher systemic bioavailability from Pentasa warrants monitoring of the renal function.