3-((7R,8S,10R,11R,13S,14S,17R)-11,17-dihydroxy-7-(methoxycarbonyl)-10,13-dimethyl-3-oxo-2,3,6,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)propanoic acid, sodium salt