Estradiol sulfate
As the sodium salt, sodium estradiol sulfate, E2S is present as a minor constituent (0.9%) of conjugated equine estrogens (CEEs), or Premarin. It effectively functions as a prodrug to estradiol in this preparation, similarly to E1S. E2S is also formed as a metabolite of estradiol, as well as of estrone and E1S. Aside from its presence in CEEs, E2S is not available as a commercial pharmaceutical drug.
Estradiol monopropionate
Estradiol monopropionate (brand names Acrofollin, Agofollin, Akrofollin, Di-Ovahormon Depot, Follhormon, Ovocylin), also known as estradiol 17β-propionate or estradiol 17β-propanoate, as well as estra-1,3,5(10)-trien-3,17β-diol 17β-propionate, is a synthetic, steroidal estrogen and an estrogen ester – specifically, the C17β propionate ester of estradiol – which was first marketed in the late 1930s or early 1940s.