Estradiol (medication)
Estradiol is available in a variety of different formulations, including oral, intranasal, transdermal/topical, vaginal, injectable, and implantable preparations. An ester may be attached to one or both of the hydroxyl groups of estradiol to improve its oral bioavailability and/or duration of action with injection. Such modifications give rise to forms such as estradiol acetate (oral and vaginal), estradiol valerate (oral and injectable), estradiol cypionate (injectable), estradiol benzoate (injectable), estradiol undecylate (injectable), and polyestradiol phosphate (injectable; a polymerized ester of estradiol), which are all prodrugs of estradiol.
Estetrol/drospirenone
Estetrol/drospirenone (E4/DRSP; tentative brand name Estelle; developmental code name FSN-013) is a combination of estetrol, an estrogen, and drospirenone, a progestin, which is under development by Estetra S.A. as a combined oral contraceptive for the prevention of pregnancy in women. It contains 15 mg estetrol and 3 mg drospirenone. As of 2018, it is in phase III clinical trials for this indication.