PT  - JOURNAL ARTICLE
AU  - L S Zhang
AU  - T Yoshida
AU  - K Aoki
AU  - Y Kuroiwa
TI  - Metabolism of cinobufagin in rat liver microsomes. Identification of epimerized and deacetylated metabolites by liquid chromatography/mass spectrometry.
DP  - 1991 Sep 01
TA  - Drug Metabolism and Disposition
PG  - 917--919
VI  - 19
IP  - 5
4099  - http://dmd.aspetjournals.org/content/19/5/917.short
4100  - http://dmd.aspetjournals.org/content/19/5/917.full
SO  - Drug Metab Dispos1991 Sep 01; 19
AB  - The metabolism of cinobufagin (CB) in rat liver microsomes was studied. By comparison of retention times and fragmentation patterns obtained by thermospray LC/MS with those of authentic standards, four metabolites of CB were also identified, in addition to deacetylCB (M1) and 3-epideacetylCB (M2), which have been reported previously. The additional four metabolites were identified to be 3-epiCB (M4), 3-ketoCB (M5), 3-keto-16 beta-OH-deacetylCB (M3), and 3-keto-16 alpha-OH-deacetylCB (M6). The primary metabolic products of CB were M1 and M2, with a small amount of M4 and trace amounts of M3, M5, and M6. These results indicate that major metabolic routes of CB were deacetylation at the 16-position and epimerization at the 3-position via the 3-keto intermediate.