Abstract
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.