DDVP (Dichlorvos Vapona) [2,2-dichlorovinyl dimethyl phosphate} 
Using whole homogenates of rat and rabbit tissues, the course of | 
metabolism of DDVP-P?2 was followed. In liver, kidney, spleen, and 
adrenal glands, the principal metabolite was dimethyl phosphate (50-852). | 
The remainder appeared as O-methyl 2,2-dichlorovinyl phosphate, monomethyl 
phosphate, and inorganic phosphate. In plasma, 98-100% of the DDVP 
hydrolyzed was accounted foras dimethyl phosphate. When dimethyl phosphate- 
p32 was incubated with liver homogenates or plasma, all radioactivity was 
recovered as unchanged dimethyl phosphate. In the presence of a rat liver 
soluble preparation, DDVP was degraded to dichloroacetaldehyde and some 
dichloroacetic acid. The aldehyde was reduced to the corresponding alcohol 
which was excreted as the glucuronide. Similar results were obtained with‘ 
a rat, cow, and goat following oral or intraperitoneal administration (274, 
678). 
32p-labeled DDVP was used to study dermal absorption incows. The maximum 
of 0.3 ppm was reached in blood very quickly. Large amounts of 32 p_metab- 
olites were immediately excreted via the urine. A part of the DDVP seemed 
to be reversibly bound to protein in the blood and was slowly freed. In 
vitro studies with serum indicated small amounts of desmethyl DDVP but 
large amounts of dimethylphosphate. In milk, the maximum level attained 
was 0.1 ppm; and six to eight hours post-treatment this fell to less than 
0.005 ppm DDVP. Examination of the urine showed large amounts of dimethyl- 
phosphate and small amounts of desmethyl DDVP (1656). 
Studies with houseflies have shown that dipterex is converted to DDVP 
which in turn is degraded to dimethyl phosphate and dichloroacetaldehyde 
(973). 
Pesudomonas _melophthora and Trichoderma viride degraded DDVP but no 
metabolites were identified (145, 1622). 
The half-life of DDVP at 2 ppm in aqueous solution at 38°C is 60 hours 
at pH=1 and 4.5 hours at pH=9.1. In saturated aqueous solution containing 
1% DDVP, its hydrolysis rate is about 3% per day at room temperature. DDVP 
also decomposes rapidly when sorbed onto the majority of solid carriers even 
when the carriers have been dried (42). 
After exposure of bluegill, (Lepomis macrochirus Rafinesque) and 
channel catfish (Ictalurus punctalus Walbaum) to DDVP, chromatography 
revealed the presence of dimethylphosphate and dichloroacetaldehyde 
(1681). 
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