Localization of salazopyrin in colonic mucosa patients with ulcerative colitis

In this study SASP metabolite levels were measured in colonic mucosal specimens and plasma samples from 31 patients with ulcerative colitis (UC) under treatment with the drug. Colonic tissue specimens were obtained by endoscopically guided biopsy and plasma was isolated from peripheral blood. Measurements were performed by HPLC according to the procedure of Fischer et al. The levels of 5-ASA and SP in either of colonic tissue or plasma were significantly lower than those of Ac-5-ASA and Ac-SP, respectively. The tissue level of 5-ASA had a significant correlation to the dosage of 5-ASA. The tissue levels of 5-ASA and Ac-5-ASA were low in an active stage of UC than during a remission period and the difference observed with respect to the latter metabolite was significant. These findings suggest that acetylation of 5-ASA is inhibited in the colonic mucosa in an active stage of the disease.