Absorption, Metabolism, and Excretion of Tritium-Labeled Famphur in the Sheep and Calf

Abstract

The metabolism of famphur, 0,0-dimethyl , -(lV,Ar-dimethylsulfamoyl)phenyl phosphorothioate, in the sheep and calf involves rupture of P-Omethyl, P--phenyl, and TV-methyl bonds to yield water-soluble metabolites which are eliminated in the urine. Phenolic metabolites are excreted primarily as glucuronide derivatives. Marked differences in metabolism and excretion patterns occur depending on the method of administration, intramuscular injection providing more sustained famphur levels, and lower famoxon levels in blood than intravenous administration.

Elimineringshastigheten av famphur — en fosforparasiticid — hos ren

“…Famoxon was included in the residue studies because it is the loxicologically most important metabolite ( Gatterdam et al 1967). In plasma, famoxon usually constituted only about 0.1 of the famphur content, this being in agreement wi,th results obtained with cattle and sheep by Gatterdam et al These workers…”

“…From a food hygienic point of view it is essential to know the fate of any chemical applied to animals involved in food production. According to studies reported by Zach!frl et al (1965), Gatterdam et al (1967) and Pasarela et al (1967) famphur is rather rapidly metabolized and excreted in cattle. Of the metabolites of famphur only the oxygen analogue, famoxon, seems to be distinctly toxic to mammals.…”