Separation of fulvestrant isomers

摘要

The invention encompasses methods of separating the isomers of fulvestrant comprising placing a fulvestrant sample on a HPLC using a reverse phase column or chiral column; eluting the sample with an eluant having a first mobile phase and a second mobile phase; and collecting purified fractions of fulvestrant sulfoxide A or fulvestrant sulfoxide B from the column. The method provides fulvestrant sulfoxide A or fulvestrant sulfoxide B in 99.5% purity as determined by HPLC.