Fulvestrant is a white powder with a molecular weight of 606.77. The solution for injectionis a clear, colorless to yellow, viscous liquid.Each injection contains as inactive ingredients: Alcohol, USP, Benzyl Alcohol, NF, and Benzyl Benzoate, USP, as co-solvents, and Castor Oil, USP as a co-solvent and release rate modifier.FASLODEX is supplied in sterile single patient pre-filled syringes containing 50-mg/mL fulvestrant either as a single 5 mL or two concurrent 2.5 mL injections to deliver the required monthly dose. FASLODEX is administered as an intramuscular injection of 250 mg once monthly.