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Title: Metabolism of cibenzoline in dogs

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:6762746

The disposition of /sup 14/C-cibenzoline in male dogs after oral administration of 13.8 mg/kg of cibenzoline base, 4,5-dihydro-2-(2,2-diphenylcyclopropyl)-1H-imidazole, was investigated. Unchanged drug was the major excreted component in 0-24 h urine from 3 dogs, ranging from 32.2-56.6% of the dose. A phenolic metabolite was purified by TLC after Glusulase hydrolysis and identified by NMR and MS as p-hydroxycibenzoline in rearranged form, rac-4-(5-phenyl(2,3,6,7-tetrahydro-5H-pyrrolo-(1,2-a)imidazol-5-yl)) phenol. The 0-24 h urine contained 4-5% of the dose as this compound. The conditions leading to rearrangement of synthetic p-hydroxycibenzoline, trans-rac-4-(2-(4,5-dihydro-1H-imidazol-2-yl)-phenylcyclopropyl) phenol, were investigated. These studies suggested that unrearranged p-hydroxycibenzoline was excreted and that rearrangement occurred predominantly during the purification procedure. Unchanged cibenzoline, purified from urine, was analyzed by ORD/CD and found to display slight optical activity, corresponding to an optical purity of 15%. Shape of the spectra and sign (minus) were those of reference S(-) cibenzoline. p-Hydroxycibenzoline and its rearranged analog were only slightly active in inhibiting ventricular arrhythmia in rats induced by i.v. infusion of aconitine.

Research Organization:
Hoffmann-La Roche Inc., Nutley, NJ
OSTI ID:
6762746
Report Number(s):
CONF-8604222-; TRN: 87-010462
Journal Information:
Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:4; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
Country of Publication:
United States
Language:
English