A species difference in the presystemic metabolism of carbazeran in dog and man

Xenobiotica. 1984 Dec;14(12):935-45. doi: 10.3109/00498258409151492.


The bioavailability of carbazeran and the metabolism of carbon-14 labelled drug have been studied in the dog and man following oral administration. The drug was moderately well absorbed in both species, but there was a marked difference in bioavailability and in routes of metabolism. In the dog, systemic bioavailability was approx. 68% and biotransformation involved mainly O-demethylation. In man, bioavailability was not measurable and carbazeran was almost completely cleared via 4-hydroxylation of the phthalazine moiety. Thus the lack of detectable pharmacological effect in man following oral administration of the drug appears to be due to presystemic metabolism by a particularly active pathway not found in the dog.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Animals
  • Biological Availability
  • Biotransformation
  • Carbamates / metabolism*
  • Chemical Phenomena
  • Chemistry
  • Dogs
  • Humans
  • Male
  • Species Specificity


  • Carbamates
  • carbazeran