Fulvestrant injection (brand name Faslodex) is a sterile, clear, yellow to viscous liquid solution used as an estrogen receptor antagonist for the treatment of breast cancer. It is supplied as a pre-filled syringe for intramuscular (IM) administration. 

Active IngredientStrengthVolumeFulvestrant USP/BP250 mg5 ml Prefilled Syringe (50 mg/ml)Fulvestrant USP/BP250 mg5 ml Vial (50 mg/ml)VehicleCastor Oil / Benzyl AlcoholViscous Oily Base