Cloquintocet-mexyl is a colourless crystalline herbicide safener. It is categorized as Class III toxin.
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beige solid
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Cloquintocet-mexyl is a herbicide. It is used to control coarse annual grass of the family poaceae (gramineae). lt was developed by the swiss ciba geigy in the 1980s and the patent has expired.
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Cloquintocet-mexyl is a safener that can be used in conjunction with various herbicides to reduce phytotoxicity to crops. Though effective as a safener, the manufacture, storage, and use of cloquintocet-mexyl containing products can present challenges owing to its sensitivity to water and its low melting temperature (i.e., 61-69° C. for technical material). When products containing cloquintocet-mexyl are prepared, stored, or used in the presence of water, cloquin tocet-mexyl can undergo hydrolysis to form cloquintocet acid, and/or form a needle-shaped, crystalline hydrate that can, lead to clogged spray nozzles during spray applications and/or possibly increased levels of crop phytotoxicity.
Carcinogenicity
In accordance with the EPA Proposed EPA Weight-of-the-Evidence Categories, August 1999, the HIARC classified cloquintocet-mexyl as "not likely to be a human carcinogen." Carcinogenicity studies in rats and mice did not show increased incidence of spontaneous tumor formation. With negative mutagenic test battery, it is suggested that cloquintocet-mexyl (CGA 185072) is not likely to be a human carcinogen.
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Metabolism studies in rats indicated that approximately 40% of the administered dose of cloquintocet-mexyl was absorbed through the gastrointestinal tract and subsequently excreted via the urine. Fecal excretion accounted for approximately 60% of the administered dose. The chemical was rapidly eliminated (more than 80% of the administered dose) via feces and urine within 48 hours post-dosing. Sex, dosing regime, and dose levels had little effect on the excretion pattern. Excretion patterns were similar between the biliary cannulated and non-cannulated animals indicating that there was no enterohepatic circulation of the chemical. Three days after administration, tissue radioactivity accounted for less than 0.3% of the administered dose (or was non-detectable) and was not detectable in the expired air. At day three post-dosing, most tissue residues of radioactivity were below the limit of detection. The major metabolic pathway of cloquintocet-mexyl was ester hydrolysis to yield 5-chloro-8-quinolinoxy acetic acid, the major metabolite in the fecal and urinary pools.
