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.
Estradiol acetylsalicylate
Estradiol acetylsalicylate, or estradiol 3-acetylsalicylate, is a synthetic estrogen and estrogen ester – specifically, the C3 acetylsalicylic acid (aspirin) ester of estradiol – which was described in the late 1980s and was never marketed. In dogs, the oral bioavailability of estradiol acetylsalicylate was found to be 17-fold higher than that of unmodified estradiol. However, a subsequent study found that the oral bioavailability of estradiol and estradiol acetylsalicylate did not differ in rats (4.3% and 4.2%, respectively), suggestive of a major species difference.