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.
Desogestrel
Desogestrel is available widely throughout the world, including in the United States, Canada, the United Kingdom, Ireland, many other European countries, Australia, New Zealand, South Africa, Latin America, South, East, and Southeast Asia, and elsewhere in the world. In the United States, it is available only in combination with ethinylestradiol as a combined oral contraceptive; it is not available alone and is not approved for any other indications in this country.