Title: Selective toxicity of phoxim (phenylglyoxylonitrile oxime O,O-diethyl phosphorothioate)
Abstract: Phoxim (phenylglyoxylonitrile oxime O,O-diethyl phosphorothioate) and a series of analogs have been examined for toxicity to insects and the white mouse. These compounds were generally quite toxic to insects and, with the exception of the phosphonate derivative, were virtually nontoxic to mice. The PO esters were all potent inhibitors of both bovine erythrocyte and housefly-head cholinesterase but they were somewhat more effective in inhibiting the latter. Although differences in cholinesterase sensitivity to inhibition may contribute to the selective toxicity of phoxim, the evidence indicates that metabolism may play an even more important role. In mice, phoxim is rapidly degraded to nontoxic hydrolysis products. The most important pathway appears to involve desulfuration of phoxim to PO phoxim which in turn is hydrolyzed with extreme rapidity to diethyl phosphoric acid and critical levels of PO phoxim in the mouse are not reached. In addition, pathways involving cleavage of phoxim to O,O-diethyl phosphorothioic acid and hydrolysis of the cyano group to the carboxylic acid also were found to be important. The latter appeared to increase in importance as the administered dose was increased. Relatively large amounts of phoxim and PO phoxim were found internally in susceptible flies but phoxim was rapidly metabolized in organophosphate-resistant flies to nontoxic products. As in the mouse, hydrolysis of the PO phoxim to diethyl phsophoric acid evidently was the predominant pathway for degradation in resistant flies.
Publication Year: 1971
Publication Date: 1971-03-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 15
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