title: Effect of age on levels of diazepam in plasma and brain of rats.
abstract: The pharmacokinetics and distribution in brain and cerebellum of diazepam after a single dose were studied in middle aged (6 months) and old (18 months) rats. Following the single intravenous bolus of 5 mg/kg diazepam was eliminated more slowly in old rats (T 1/2 (beta) = 3.1 H) than in middle aged rats (1.4H). This was due to an increase in the apparent volume of distribution Vd beta from 11.0 l/kg (control rats) to 29.5 l/kg. Concentrations of diazepam in brain and cerebellum were in the same range (0.5-1.1 ng/mg) in both groups after this dose. We conclude that the distribution of diazepam is age-dependent which might be due to an altered body composition.
mesh_terms: D000375:Aging; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D002531:Cerebellum / Q000378:metabolism; D003975:Diazepam / Q000097:blood / Q000378:metabolism*; D006207:Half-Life; D008297:Male; D051381:Rats; D013997:Time Factors
chemical_list: D003975:Diazepam