AGRO 3 |
| Imidacloprid (IMI), nitenpyram (NIT), thiacloprid (THI), and acetamiprid (ACE) have in common the 6-chloro-3-pyridinylmethyl group but differ in the nitroguanidine, nitromethylene or cyanoamidine substituent on an acyclic or cyclic moiety. They were administered ip to mice at 10-20 mg/kg for analysis of brain, liver, plasma, and urine by HPLC/DAD, LC/MSD, and LC/MS/MS. Each compound was partially cleaved leading to the same eight urinary chloropyridinylmethyl-derived metabolites and various fragments from the rest of the molecule. IMI gave nitrosoguanidine, aminoguanidine, guanidine, olefin, methyltriazinone, and hydroxy- and dihydroxyimidazole derivatives. NIT metabolism involved N-demethylation and conversion of the nitromethylene substituent to carboxylic acid and cyano derivatives. THI yielded olefin, descyano, descyano olefin, urea, and hydroxythiazolidine metabolites and a ring-opened and methylated THI sulfoxide. ACE formed N-desmethyl and acetamide derivatives plus chloropyridinylmethylamine and N-methylchloropyridinylmethylamine. Despite their common metabolites, these neonicotinoids differ greatly in their sites of metabolism and persistence in mice. |
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Agrochemical Residue & Metabolism Chemistry
8:30 AM-11:30 AM, Sunday, 10 September 2006 San Francisco Marriott -- Salon 1, Oral
Division of Agrochemicals |