Spectrum Chemical manufactures and distributes fine chemicals with quality you can count on including those with CAS number 57-63-6, Whether you call it Ethinyl Estradiol, Ethinyloestradiol , 17-Ethynylestradiol , 17&#945, -Ethynylestra-1 -3 -5(10)-triene-3 -17&#223 or -diol you can be assured the Ethinyl Estradiol products offered by Spectrum, meet or exceed the grade requirements or specifications for each individual product.