TOXICITY STUDIES ON TANNIC ACID ADMINISTERED BY ENEMA

1. EFFECTS OF ENEMA-ADMINISTERED TANNIC ACID ON THE COLON AND LIVER OF RATS

¹ From the Departments of Pathology, Radiology, and Pharmacy, University of California, San Francisco Medical Center, San Francisco, California

1. Based on the 1 minute forced retention studies, the lowest concentration of a tannic acid or clysodrast containing enema producing liver necrosis was 8 per cent. Based on the extreme condition of a forced 1 hour retention enema, liver damage was detected at the 2.5 per cent level.

2. Colonic "damage" exceeding the resorbable edema and minor inflammation observed in some controls again was a function of dose and contact time. Coagulative necrosis and hemorrhage of colonic tissue, persisting for 72 hours, were seen after 16 per cent tannic acid or clysodrast containing 1 minute enemas and 4 per cent clysodrast containing enemas forcefully retained for 1 hour. Under this condition, liver damage was almost invariably associated with these alterations in colonic mucosa. At the highest levels death occurred in 8 of 22 animals prior to the 24 and 72 hour times of scheduled sacrifice.

3. At the concentrations (0.25 per cent to 2.0 per cent) employed, 3 consecutive 1 minute retention enemas given at half-hour intervals did not produce liver damage in animals sacrificed at 72 hours.

4. There was no detectable difference between the colonic or hepatotoxic effects of clysodrast and tannic acid.

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