Device for monitoring 14CO2 in the expired air from beagle dogs: its use in the study of aminopyrine demethylation.

Abstract

1. A device for serial collection of samples for determination of 14CO2 in the expired air of the beagle dog is described. 2. The device has been evaluated using [14C]aminopyrine as a model compound. The rate of 14C excretion in the expired air initially correlated with the plasma concentrations of aminopyrine rather than the plasma concentrations of 14C. 3. The dog demethylated aminopyrine at the slower rate than the rat. Both species demethylate the unchanged drug more readily than subsequent metabolites.