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In NTP TR 275 a summary is given of avaialable literature on toxicokinetics (page 20 -21):

"No reports were found on the kinetics of the dermal absorption of 2-chloroethanol or on the tissue distribution of 2-chloroethanol following dermal absorption. After a single oral dose of an aqueous solution of [1,2 -14C-2 -chloroethanol (5 or 50 mg/kg) was administered to adult male Wistar rats, 77%-80% of the administered radioactivity was recovered in the urine within 24 hours (Grunow and Altmann, 1982). In the same time period, another 3%-5% was recovered in the feces and expired air. No unchanged 2 -chloroethanol was recovered in either feces or urine; expired 14C was all in the form of 14CO2. Peak levels of radioactivity were found in blood 1 hour after administration; these levels were reduced by 50% after approximately 4 hours. About 90% of the radioactivity in the urine was in the form of thiodiacetic acid and thiodiacetic acid, the latter probably formed by the oxidation of the former metabolite.

Johnson (1965) suggested that the toxicity of 2 -chloroethanol was due to the formation of chloroacetaldehyde by the test animal in amounts greater than could be detoxified by glutathione (GSH). 2-Chloroethanol is known to be a substrate for the purified cytoplasmic alcohol dehydrogenase of human liver (Blair and Vallee, 1966), rat liver, or yeast (Johnson, 1967). Johnson (1967) demonstrated the in vivo and in

vitro formation of S-carboxymethyl-GSH in livers of rats dosed with 2-chloroethanol. S-Carboxymethyl-GSH is presumably formed from GSH and chloroacetaldehyde, the dehydrogenation product of 2-chloroethanol; S-formylmethyl-GSH is the presumed intermediate. Grunow and Altmann (1982) reported finding thiodiacetic acid and thionyldiacetic acid in the urine of rats given an oral dose of 2 -chloroethanol; both and are derivable

from S-carboxymethylcysteine, the hydrolysis and deamination product of S-carboxymethyl-GSH. Thiodiacetic acid has been shown to be a metabolite of compounds that have the general property of being converted to chloroacetaldehyde; these compounds include vinyl chloride (Green and Hathway, 1975, 1977; Watanabe et al., 1976), 1,2-dichloroethanol (Yllner, 1971), and vinylidene chloride (Jones and Hathway, 1978).