Estramustine phosphate sodium, an antineoplastic agent, is an off-white powder readily soluble in water. EMCYT Capsules are white and opaque, each containing estramustine phosphate sodium as the disodium salt monohydrate equivalent to 140 mg estramustine phosphate, for oral administration. Each capsule also contains magnesium stearate, silicon dioxide, sodium lauryl sulfate, and talc. Gelatin capsule shells contain the following pigment: titanium dioxide.
Chemically, estramustine phosphate sodium is estra-1,3,5(10)-triene-3,17-diol(17β)-,3-[bis(2-chloroethyl)carbamate] 17-(dihydrogen phosphate), disodium salt, monohydrate. It is also referred to as estradiol 3-[bis(2-chloroethyl)carbamate] 17-(dihydrogen phosphate), disodium salt, monohydrate.
Estramustine phosphate sodium has an empiric formula of C23H30Cl2NNa2O6P•H2O, a calculated molecular weight of 582.4, and the following structural formula: