Species differences in the disposition and metabolism of camazepam.
After i.v. injection of camazepam, plasma camazepan concn. declined biexponentially. The half-life of the elimination phase (t1/2, beta) increased in the order: mice (0.73 h), rats (1.3 h), dogs (5.3 h). After oral dosing of camazepam, absorption was almost complete whereas systemic availability varied eight-fold, i.e., rats and mice (10-15%) less than dogs and monkeys (about 60%) less than humans (greater than 90%), indicating species difference in the first-pass effect. Camazepam was metabolized extensively in all species investigated to more than 10 metabolites, which were desmethyl, descarbamoyl and/or hydroxy products. In comparison with camazepam, plasma concn. of pharmacologically active metabolites, temazepam, oxazepan and hydroxy camazepam, were much higher in rats and mice than in dogs and monkeys.
Morino
A
A
Nakamura
A
A
Nakanishi
K
K
Tatewaki
N
N
Sugiyama
M
M
D000818:Animals; D014151:Anti-Anxiety Agents / Q000378:metabolism*; D001798:Blood Proteins / Q000378:metabolism; D055598:Chemical Phenomena; D002621:Chemistry; D002855:Chromatography, Thin Layer; D004285:Dogs; D005243:Feces / Q000032:analysis; D006207:Half-Life; D000882:Haplorhini; D007700:Kinetics; D008297:Male; D008433:Mathematics; D051379:Mice; D010076:Oxazepam / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity; D013693:Temazepam / Q000378:metabolism*
D014151:Anti-Anxiety Agents; D001798:Blood Proteins; D010076:Oxazepam; D013693:Temazepam