Food Additives & Contaminants 1991-01-01

The identification and assay of 2-methyl-5-nitroimidazole in pigs treated with dimetridazole.

G Carignan, K Carrier, S Sved

Index: Food Addit. Contam. 8(4) , 467-75, (1991)

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Abstract

An unidentified metabolite of dimetridazole (DMZ), found in pig plasma, muscle and kidney, was shown by chromatography and spectroscopy to be 2-methyl-5-nitroimidazole (2-MNI), resulting from N-demethylation of DMZ. This route of degradation competes with the oxidation pathway previously described. The concentration of 2-MNI in the plasma of pig fed medicated diet (DMZ 0.0125%) ranged from 29 to 83 ppb, 2 hours after the morning meal, similar to DMZ, but lower than that of the major metabolite, 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI). Its elimination profile in plasma was biphasic, similar to those of HMMNI and DMZ. Early and terminal half lives were 2.6 and 9.1 h respectively. None of the metabolites could be detected in any of the tissues studied 49 hours after withdrawal.