Fluorometholone Impurity:(4aS,4bS,6S,10aS,10bR,11S,12aS)-10b-Fluoro-1,11-dihydroxy-1,6,10a,12a-tetramethyl-4,4a,4b,5,6,10a,10b,11,12,12a-decahydrochrysene-2,8(1H,3H)-dione;.