Biotransformation of methyl 5-cyclopropylcarbonyl-2-benzimidazolecarbamate (ciclobendazole) in rats and dogs.
A major metabolite of ciclobendazole (methyl 5-cyclopropylcarbonyl-2-benzimidazolecarbamate) excreted in the urine, bile, and feces of rats was methyl 5-cyclopropylcarbonyl-6-hydroxy-benzimidazolecarbamate, established by comparison of the proton magnetic resonance and mass spectra with that of the authentic compound. This compound represented 8.2% and 7.1% of the dose, respectively, in extracts of 24-hr urine and 48-hr feces samples of rats, but was only a minor metabolite in dog urine (1% of the dose). The unchanged drug was only detected in dog feces, the major route of excretion of radioactivity in the dog. 5-Cyclopropylcarbonyl-2-amino-benzimidazole was present in rat urine (2.5% of the dose). A major metabolite in dog bile was probably 5-cyclopropylcarbinol-2-aminobenzimidazole, formed by loss of the methoxycarbonyl group and reduction of the carbonyl function in the 5-position.
D000818:Animals; D000871:Anthelmintics / Q000378:metabolism* / Q000652:urine; D001562:Benzimidazoles / Q000378:metabolism* / Q000652:urine; D001646:Bile / Q000378:metabolism; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D003521:Cyclopropanes / Q000378:metabolism* / Q000652:urine; D004285:Dogs; D005243:Feces / Q000032:analysis; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D051381:Rats
D000871:Anthelmintics; D001562:Benzimidazoles; D003521:Cyclopropanes