Disposition and metabolism of chloramphenicol in trout

The urinary and faecal excretion, tissue distribution and metabolism of 3H-chloramphenicol (CP) were measured in rainbow trout, Salmo gairdneri R., after a single 50 mg/kg intragastric dose. The major route of excretion of 3H was faecal (64.3% of the dose), with approx. 16% in the urine in five days. Radioactivity was widely distributed in trout tissues and organs, the highest concen. being in the bile and intestine. At 48 h after dosing, the radioactivity remaining in the liver, the muscle and the perigastric adipose tissue was as CP-derived compounds bound to tissues. In addition to unchanged CP (4.3% dose after 96 h), the other metabolites excreted in the urine were CP base (5.2%), CP alcohol (4.0%) and CP glucuronide (1.8%).