地高辛EP杂质A（洋地黄毒苷）

4-((3S,5R,8R,9S,10S,13R,14S,17R)-3-(((2R,4S,5S,6R)-5-(((2S,4S,5S,6R)-5-(((2S,4S,5S,6R)-4,5-dihydroxy-6-methyltetrahydro-2H-pyran-2-yl)oxy)-4-hydroxy-6-methyltetrahydro-2H-pyran-2-yl)oxy)-4-hydroxy-6-methyltetrahydro-2H-pyran-2-yl)oxy)-14-hydroxy-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-17-yl)furan-2(5H)-one