Bioavailability, metabolism, and renal excretion of benzoic acid in the channel catfish (Ictalurus punctatus)
Plakas, S.M.; James, M.O.
Drug Metabolism and Disposition the Biological Fate of Chemicals 18(5): 552-556
1990
ISSN/ISBN: 0090-9556 PMID: 1981701 Document Number: 362635
The pharmacokinetics and metabolism of the model compound benzoic acid were examined after intravascular (iv) and po administration at 10 mg/kg in the channel catfish (Icatalurus punctatus). A two-compartment pharmacokinetic model best described the plasma disposition of parent benzoic acid after iv dosing. The following pharmacokinetic values were estimated: elimination half-life, 5.9 hr; total body clearance, 61 ml/hr/kg; and volume of distribution (steady-state), 369 ml/kg. Plasma protein binding of [14C]benzoic acid was 18%. Benozic acid was rapidly and extensively absorbed after po administration; absorption half-life was 0.8 hr and bioavailability was 95%. Renal excretion was the primary route of elimination of benzoic acid and metabolites. More than 80% of the iv-administered 14C was recovered in the urine in 24 hr. Unchanged benzoic acid comprised more than 90% of the urinary radiolabel. The major urinary metabolite was benzoyltaurine, which comprised 6-7% of the excreted 14C. Channel catfish were qualitatively similar to other teleost fishes in the formation of the taurine conjugate of benzoic acid. In contrast, the primary mammalian metabolite is the glycine conjugate, hippuric acid.