The effect of chrysene and some polycyclic aromatic hydrocarbons on the elimination of theophylline in rats.

The investigations of the effect of some compounds belonging to the group of polycyclic aromatic hydrocarbons (PAH), e. g. benzo[a]pyrene, chrysene, fluorene and pyrene, on the elimination of theophylline injected i. v. into rats have shown that benzo[a]pyrene and chrysene accelerate the elimination of this drug (elimination rate constant in control group: 0.2504 h-1; after benzo[a]pyrene: 0.3626 h-1; after chrysene: 0.3582 h-1). The increase of theophylline elimination rate constant by chrysene depends on its dose, and this relationship is of sigmoid type in the dose range of 1-20 mg X kg-1. Besides, dependence of theophylline elimination rate constant on the time of chrysene dosing was also shown. After oral administration of theophylline the decrease of its amount reaching the circulation by 11% was also observed, which was caused by the influence of chrysene on the first-pass effect, beside its influence on the elimination rate.