Estradiol (medication)
, estradiol is available in the United States in the following forms:Oral estradiol valerate (Progynova) and other esters of estradiol that are used by injection like estradiol benzoate, estradiol enantate, and estradiol undecylate all are not marketed in the U.S. Polyestradiol phosphate (Estradurin) was marketed in the U.S. previously but is no longer available.
Estrone (medication)
Like estradiol, estrone has poor oral bioavailability. It has been said that, taken by mouth in non-micronized form, a dose of 25 mg estrone is approximately equivalent to 2.5 mg conjugated estrogens, 50 µg ethinylestradiol, or 1 mg diethylstilbestrol in terms of estrogenic potency. Due to its weak oral activity, estrone has been used parenterally instead, for instance by intramuscular injection or vaginal administration. The pharmacokinetics of vaginal estrone have been studied.