Metabolism of 2,6-dichlorobenzamide in rats and mice

1. Oral doses of 2,6-dichlorobenzamide (DCB) were excreted by rats as DCB, two monohydroxy-DCBs, 2-chloro-5-hydroxy-6-(methylthio)benzamide and 2-chloro-5-hydroxy-6-[S-(N-acetyl)cysteinyl]benzamide (mercapturic acid). 2. Biliary excretion (33% of the dose), enterohepatic circulation and intestinal micro-floral metabolism were involved in formation of 2-chloro-5-hydroxy-6-(methylthio)benzamide, and the mercapturic acid served as a precursor. 3. Whole body autoradiography and microautoradiography showed the accumulation of non-extractable residues from DCB in the nasal mucosa and contents of the large intestines of rats and mice dosed with 14C-labelled DCB.