Identification of some urinary metabolites of propantheline bromide in man.

The peak plasma concn. of total radioactivity occurred 6 h after a single oral dose of [carboxyl-14C; methyl-2H3] propantheline bromide was administered to a healthy man. At this time 10% of the dose was present in the total plasma volume. 2. A total of 71% dose of radioactivity was excreted in urine in 96 h after dosage, 59% dose being excreted in the first 24 h. About 5.3% of the orally administered propantheline bromide was excreted unchanged. 3. T.l.c. analysis and g.l.c.-mass spectrometry showed xanthanoic acid, hydroxyxanthanoic acid(s), and propantheline as urinary metabolites of the drug. 4. A glucuronide of xanthanoic acid, a hydroxylated propantheline and the (2-hydroxyethyl)diisopropylammonium ion were tentatively identified as urinary metabolites. Hydrolysis of propantheline and conjugation of the resulting xanthanoic acid appear to be the major routes of metabolism of this compound. 5. A mean elimination half-life of 9.2 h was obtained for the total radioactivity by pharmacokinetic analysis of plasma and urine levels of 14C.