THE METABOLIC FATE OF 5-ALLYL-5-(1-METHYLBUTYL)BARBITURIC ACID (SECOBARBITAL)

¹ Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina

The three major metabolic products of secobarbital in man and the dog, viz., 5-(2,3-dihydroxypropyl)-5- ( 1 - methylbutyl) barbituric acid (secodiol) and two diastereoisomers of 5-allyl-5-(3-hydroxy-1-methylbutyl) barbituric acid (hydroxysecobarbital), were isolated from human urine and characterized.

A fourth metabolite, 5-(1-methylbutyl) barbituric acid, was found in the urine of some human patients and was identified on paper chromatograms.

5-Hydroxy-5-(1-methylbutyl) barbituric acid was identified on the same paper chromatograms that showed 5-(1-methylbutyl) barbituric acid. It is not known whether this compound was formed in vivo or in vitro.

Only the hydroxysecobarbitals were found in rat urine.

Rat liver microsome preparations incubated in vitro with secobarbital produced the hydroxysecobarbitals in the same relative proportions found in urine.

The hydroxysecobarbitals and secodiol were without anesthetic activity in mice in doses much larger than the anesthetic dose of secobarbital.

Some of the physical constants that were used in the isolation and identification of these compounds are presented.