Trichlorfon (Dipterex, Bayer L 13/59) [0,0-Dimethyl 2,2,2-Trichloro-1l- 
Hydroxyethyl Phosphonate ] 
Se banat trichlorfon was administered to a cow. Analysis of blood 
indicated a rapid hydrolysis. From urine samples, trichloroethanol 
glucuronic acid was isolated and identified. Dimethylphosphate and desmethyl 
trichlorfon were found in the milk (33, 1219, 1669). In piglets, DDVP 
appeared in the blood after subcutaneous injection of trichlorfon (1787). 
With in vitro studies with serum of cows, at 37°C, trichlorfon was degraded 
to DDVP, desmethyl trichlorfon and dimethylphosphate (1696). 
In rat brain homogenates, cl4_1abeled trichlorfon was rapidly metabolized 
to monodemethylated trichlorfon, monomethylphosphate, 2,2,2-trichloro-l- 
hydroxyethyl phosphonic acid, and a fourth unidentified compound (628). 
Following Been in rats of trichlorfon labeled in the two methyl groups, 
607.08, the oC 4 was recovered after 24 hours in the expired air and urine. 
cl49, and c!4-formate constituted about 50% of the recovered radioactivity 
(627), Additional studies were conducted with P32-labeled trichlorfon. After 
interperitoneal injection, 75-85% of the administered radioactivity appeared 
in the urine within 48 hours. Three P22-labeled compounds were found in the 
urine. Two were identified as mono- and dimethylphosphates. The third 
metabolite was not identified (632). 
After exposure of larvae of the cotton leaf worm (Prodenia lituria F.) 
to labeled trichlorfon, O-methyl-2,2,2-trichloro-l-hydroxyethyl phosphonic 
acid, Aa? ote hch Lego”) aoe iy’ phosphonic glucuronic acid (65-752), 
mono- and dimethylphosphate, and C 405 (629, 1536) were found. 
In other studies, after exposure of adult larvae of Prodenia litura F. 
to P32 labeled trichlorfon, the hemolymph contained 3 times more radioactivity 
than in the gut. While the concentration in the gut and hemolymph decreased 
with time, there was an accumulation of radioactivity in the fat. The meta- 
bolites excreted were identified as monomethyl- and dimethylphosphates, and 
the glucuronate of the demethylated trichlorfon (1537). 
When trichlorfon was mixed with digestive juices or blood of silkworm 
larvae (Bombyx mori L.), trichlorfon disappeared and DDVP appeared. At present 
however, it is not certain whether the rapid degradation of trichlorfon in the 
digestive juice (pH 10-11) was enzymatic or not. At room temperature in 
O0.1N NaOh solution, trichlorfon gave rise to several compounds, one of which 
was identified as DDVP (1595). 
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