抄録
After oral administration of noscapine (80-150 mg/kg) to male rabbits, detection of its urinary metabolites was carried out. The first 24-hr urine was extracted with CHCl3 at pH 8-9 (F-I) and the remaining urine was re-extracted with CHCl8 after acid hydrolysis (F-II). By means of thin-layer chromatography (TLC) coupled with methane chemical ionization mass spectrometry, the Dragendorffpositive spots in CHCl3 extracts were easily recognized as the metabolites. These spots were separated by two successive preparative TLC using the solvent systems of CHCl3-acetone (4 : 1) and cyclohexaneethyl acetate (2 : 3). The quasi-molecular ions of the separated metabolites suggested that these metabolites should be demethylation products. Thus, unchanged noscapine (M-1) and two O-monodemethylated metabolites (M-2 and M-3) were detected as free metabolites, and M-2, M-3, and M-4 (O-didemethylated metabolite) as conjugated metabolites. The main urinary metabolite was M-2, but it was excreted only in a small amount, same as unchanged noscapine.
