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.
Mestranol
Mestranol was employed as the estrogen component in many of the first oral contraceptives, such as mestranol/noretynodrel (brand name "Enovid") and mestranol/norethisterone (brand names "Ortho-Novum", "Norinyl"), and is still in use today. In addition to its use as an oral contraceptive, mestranol has been used as a component of menopausal hormone therapy for the treatment of menopausal symptoms.