Further Studies of Metabolic Removal of Alkyl Groups from Nitrogen in Barbituric Acid Derivatives. ∗

Summary

Analytical methods are described for the simultaneous determination in plasma of N-ethyl barbital and barbital or N-propyl barbital and barbital. These methods have been used to study the metabolic fate in the dog of the N-ethyl and N-propyl derivatives of barbital. Both of these compounds disappear slowly from the plasma. N-ethyl barbital is converted in considerable part to barbital, the concentration of that substance in plasma increasing for more than a day. N-propyl barbital is converted to barbital only to a very small extent. By means of methods previously developed for the simultaneous determination of N-methyl barbital and barbital in plasma, the fate of N;N′-dimethyl barbital has been studied. Both methyl groups are removed from this compound, the first much more rapidly than the second.