Absorption and excretion of azodisal sodium and its metabolites in man after rectal administration of a single 2-g dose.

The behaviour of azodisal sodium (ADS) and its metabolites after a single 2-g rectal dose was investigated in 10 healthy volunteers. Blood samples were drawn frequently, and urine was collected during intervals of 24 h. The ADS absorption gave a mean peak serum concentration of 2.1 (SD +/- 0.7) microgram/ml. The urinary excretion of ADS was 0.8% of the given dose. After rectal administration 5-aminosalicylic acid (5-ASA) could be detected in the serum only in two of the subjects, with a mean concentration of less than 0.5 microgram/ml. Ac-5-ASA was present in increasing serum concentrations, being 0.93 microgram/ml at 24 h. The mean 24-h urinary excretion of these two metabolites was only 2.7% of the given dose. In another study the azo bond of ADS has been shown to be split by anaerobic and aerobic bacteria. The low absorption of its metabolites indicates that ADS is a suitable molecule for delivering the presumed pharmacologically active moiety, 5-ASA.