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Uniformly ring-labeled 14C o-chlorotoluene was administered by gavage to rats at a dose of 320 mg/kg bw. Expired air, urine and faeces were examined for metabolites.

The recovery of radioactivity at 48 h averaged 11 % in the expired air, 81 % in urine, and 4 % in feces; radioactivity in expired air was identified as unchanged o-chlorotoluene; urinary metabolites (as % of dose) were: o-chlorohippuric acid (16- 20 %), a mercapturic acid conjugate of o-chlorotoluene (20- 24 %) and polar metabolites (36-43 %); enzymatic hydrolysis of rat urine indicated that the polar metabolites included the glucuronide conjugate of the phenolic hydroxylation product of o-chlorotoluene; unchanged o-chlorotoluene was not present in urine or feces of treated rats

When male and female Sprague-Dawley rats were given a single oral dose of o-chlorotoluene at 1 mg/kg bw by ga-vage, 85-92 % of the applied dose was eliminated in urine, 5-8 % was excreted in feces and 1-4 % of the ap-
plied dose was exhaled as volatile 14C; at least 84 % of the volatile 14C was identified as unmetabolized o-chlo-
rotoluene whereas 14C-carbon dioxide was an insignificant metabolite (< 1% applied dose);
A similar distribution of radioactivity was also seen in female rats given single oral doses of 91 or 102 mg/kg bw;
The major urinary and fecal metabolites were o-chlorohippurate, a beta-glucuronide
of o-chlorobenzyl alcohol and mercapturic acid; no significant sex-related metabolic differences were noticed between
males and females and the same qualitative and quantitative distribution of metabolites was found for doses of 1-102 mg/kg bw;
o-Chlorotoluene is quickly absorbed from the gastrointestinal tract into blood as evidenced by exhalation of o-chlorotoluene and the rapid peak in 14C residues at ca. 2 h in blood plasma;
analysis of the 14C residues in plasma showed that the two major radioactive components were mercapturic acid and the beta-glucuronide of o-chlorobenzyl alcohol (38 and 25 % of plasma 14C, respectively), while trace levels of o-chlorotoluene, o-chlorobenzoic acid, o-chlorobenzyl alcohol and o-chlorohippurate were detectable also; virtually all of the administered o-chlorotoluene was
eliminated within 4 d with < 1% remaining in the carcass.