Ethinyl Estradiol EP Impurity B; 9,11-Dehydro Ethynyl Estradiol; (17ฮฑ)-19-Norpregna-1,3,5(10),9(11)-tetraen-20-yne-3,17-diol; Delta-9,11-Ethinyl Estradiol; ฮด9,11-Ethinyl Estradiol; ฮ9,11-Ethinyl estradiol,(8S,13S,14S,17R)-17-ethynyl-13-methyl-7,8,12,13,14,15,16,17-octahydro-6H-cyclopenta[a]phenanthrene-3,17-diol,Estradiol Impurity