2. Use of fulvestrant in the preparation of a pharmaceutical formulation for the treatment of breast cancer by intra-muscular administration, wherein the formulation comprises fulvestrant,
30% or less weight of a pharmaceutically acceptable alcohol
per volume of formulation, at least 1% weight of a pharmaceuti-
cally-acceptable non-aqueous ester solvent miscible in a ricinoleate vehicle per volume of formulation and a sufficient amount
of a ricinoleate vehicle so as to prepare a formulation which is
capable after injection of attaining a therapeutically significant
blood plasma fulvestrant concentration for at least 2 weeks.