In vitro biotransformation of thiazopyr by rat liver microsomes: oxidative cleavage of a carboxylic methylester by monooxygenases.
1. Thiazopyr was metabolized by liver microsomes from male Sprague-Dawley rats to a previously unidentified metabolite. 2. The new metabolite was identified by coelution with an authentic standard in hplc and by electrospray lc/ms as the corresponding carboxylic acid. 3. Formation of the carboxylic acid metabolite was inhibited in the presence of mono-oxygenase inhibitors including piperonyl butoxide, 1-aminobenzotriazole, metyrapone and tetcyclacis. 4. Transformation of thiazopyr to its carboxylic acid by rat liver microsomes is mediated by mono-oxygenases and not hydrolases.
Agricultural Group, Monsanto Co., St Louis, MO 63198.
P C
PC
Feng
R T
RT
Solsten
D000818:Animals; D001711:Biotransformation; D002264:Carboxylic Acids / Q000378:metabolism; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D006540:Herbicides / Q000493:pharmacokinetics*; D066298:In Vitro Techniques; D008297:Male; D013058:Mass Spectrometry; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009525:Niacin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D010084:Oxidation-Reduction; D051381:Rats; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D013844:Thiazoles / Q000493:pharmacokinetics*
D002264:Carboxylic Acids; D006540:Herbicides; D013844:Thiazoles; D009525:Niacin; C091707:thiazopyr; D006899:Mixed Function Oxygenases