Detection and mass spectrometric characterization of the major urinary and fecal metabolites of 9-methyl-1,2,3,4,6,7,12,12b-octahydroindolo[2,3-a]-quinolizine in the rat

The metabolic fate of 9-methyl 1,2,3,4,6,7,12,12b-octahydroindolo[2,3-a]quinolizine (MIQ), a compound with promising pharmacological action on the CNS system, was investigated in the rat after an oral dose of 200 mg/kg, the maximal tolerated dose. Urine and feces were collected, exhaustively extracted with organic solvents and the metabolites detected by TLC analysis. The structures of the isolated metabolites were characterized by several mass spectrometry techniques (FD, EI, CI) and, in some cases, confirmed by synthesis. The major metabolic pathways of MIQ in the rat involve: C-oxidation of the methyl group in position 9 to a primary alcohol and to a carboxylic acid, N-oxidation of basic nitrogen and C-oxidation of the quinolizidine nucleus, probably at position 7.