Estradiol stearate
Estradiol stearate (brand name Depofollan), or estradiol octadecanoate, is a naturally occurring steroidal estrogen and an estrogen ester – specifically, the C17β stearate ester of estradiol. It occurs in the body as a very long-lasting metabolite and prohormone of estradiol. In addition, estradiol stearate is or has been available as a pharmaceutical drug for use via depot intramuscular injection. The drug was introduced in 1941 as Depofollan and was the first long-acting estrogen, although it has never been widely used. It has been reported in at least one source to have a duration of at least one month.
Segesterone acetate
A combination of SGA and the estrogen estradiol is under development in a transdermal gel formulation for use as a contraceptive in women by the Population Council in conjunction with Antares Pharma in the United States and Europe. As of December 2017, it is in phase III clinical trials for this indication. The medication has the tentative brand name NestraGel. A combination of SGA and the estrogen ethinylestradiol is under development in a vaginal ring formulation for use as a one-year contraceptive by the Population Council in multiple regions including Latin America, Europe, and Australia. It has completed phase III clinical trials and efforts are underway to pursue regulatory approval. It was approved in the United States in August 2018.