The anaerobic metabolism of metronidazole forms N-(2-hydroxyethyl)-oxamic acid.
N-(2-hydroxyethyl)-oxamic acid is formed when metronidazole is reduced either chemically or by the action of the intestinal bacteria. When metronidazole, labeled with carbon-14 in the hydroxyethyl side chain, is administered by gavage to rats in doses of 200 mg/kg, an average of 1.4% of the administered radioactivity is recovered in the urine in the form of N-(2-hydroxyethyl)-oxamic acid. The presence of conjugated N-(2-hydroxyethyl)-oxamic acid in some samples was suggested by the detection of small additional amounts of the free acid after treatment of the urine with beta-glucuronidase. The metabolite is not found in the feces. In contrast N-(2-hydroxyethyl)-oxamic acid is not found in the urine or feces of germfree rats which receive metronidazole. Thus, the finding of N-(2-hydroxyethyl)-oxamic acid in the urine of rats which receive metronidazole appears to depend on the activity of the bacterial flora.
D000693:Anaerobiosis; D000818:Animals; D001711:Biotransformation; D002432:Cecum / Q000378:metabolism; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D005243:Feces / Q000032:analysis; D005856:Germ-Free Life; D007783:Lactones / Q000378:metabolism; D008297:Male; D008795:Metronidazole / Q000378:metabolism* / Q000652:urine; D010072:Oxamic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D010084:Oxidation-Reduction; D051381:Rats
D007783:Lactones; D008795:Metronidazole; D010072:Oxamic Acid