Equilin is a naturally occurring estrogen sex hormone found in horses as well as a medication. It is one of the estrogens present in the estrogen mixtures known as conjugated estrogens and esterified estrogens. CEEs is the most commonly used form of estrogen in hormone replacement therapy (HRT) for menopausal symptoms in the United States. Estrone sulfate is the major estrogen in CEEs while equilin sulfate is the second major estrogen in the formulation, present as about 25% of the total.
Exemestane, sold under the brand name Aromasin among others, is a medication used to treat breast cancer. It is a member of the class of antiestrogens known as aromatase inhibitors. Some breast cancers require estrogen to grow. Those cancers have estrogen receptors (ERs), and are called ER-positive. They may also be called estrogen-responsive, hormonally-responsive, or hormone-receptor-positive. Aromatase is an enzyme that synthesizes estrogen. Aromatase inhibitors block the synthesis of estrogen. This lowers the estrogen level, and slows the growth of cancers.
Androstenediol, or 5-androstenediol, also known as androst-5-ene-3β,17β-diol, is an endogenous weak androgen and estrogen steroid hormone and intermediate in the biosynthesis of testosterone from dehydroepiandrosterone (DHEA). It is closely related to androstenedione (androst-4-ene-3,17-dione).
An estrogen ester is an ester of an estrogen, most typically of estradiol but also of other estrogens such as estrone, estriol, and even nonsteroidal estrogens like diethylstilbestrol. Esterification renders estradiol into a prodrug of estradiol with increased resistance to first-pass metabolism, slightly improving its oral bioavailability. In addition, estrogen esters have increased lipophilicity, which results in a longer duration when given by intramuscular or subcutaneous injection due to the formation of a long-lasting local depot in muscle and fat. Conversely, this is not the case with intravenous injection or oral administration. Estrogen esters are rapidly hydrolyzed into their parent estrogen by esterases once they have been released from the depot. Because estradiol esters are prodrugs of estradiol, they are considered to be natural and bioidentical forms of estrogen.
Benorterone, also known by its developmental code name SKF-7690 and as 17α-methyl-B-nortestosterone, is a steroidal antiandrogen which was studied for potential medical use but was never marketed. It was the first known antiandrogen to be studied in humans. It is taken by mouth or by application to skin.
Cloxestradiol (INN), also known as 17-(2,2,2-trichloroethoxy)estradiol, is a synthetic, steroidal estrogen which was never marketed. It is an analogue of estradiol with a 2,2,2-trichloroethoxy substitution. The O,O-diacetate derivative, cloxestradiol acetate, has been marketed as an estrogen.
Cloxestradiol acetate, also known as 17-(2,2,2-trichloroethoxy)estradiol O,O-diacetate, is a synthetic, steroidal estrogen derived from estradiol. It is the O,O-diacetate ester of cloxestradiol, which, in contrast to cloxestradiol acetate, was never marketed.
Orestrate (INN), also known as estradiol 3-propionate 17β-(1-cyclohexenyl) ether, is an estrogen medication and estrogen ester which was never marketed. It is the C3 propionate ester and C17β-(1-cyclohexenyl) ether of estradiol.
Methylestradiol, sold under the brand names Ginecosid, Ginecoside, Mediol, and Renodiol, is an estrogen medication which is used in the treatment of menopausal symptoms. It is formulated in combination with normethandrone, a progestin and androgen/anabolic steroid medication. Methylestradiol is taken by mouth.
Doisynolic acid is a synthetic, nonsteroidal, orally active estrogen that was never marketed. The reaction of estradiol or estrone with potassium hydroxide, a strong base, results in doisynolic acid as a degradation product, which retains high estrogenic activity, and this reaction was how the drug was discovered, in the late 1930s. The drug is a highly active and potent estrogen by the oral or subcutaneous route. The reaction of equilenin or dihydroequilenin with potassium hydroxide was also found to produce bisdehydrodoisynolic acid, the levorotatory isomer of which is an estrogen with an "astonishingly" high degree of potency, while the dextrorotatory isomer is inactive. Doisynolic acid was named after Edward Adelbert Doisy, a pioneer in the field of estrogen research and one of the discoverers of estrone.
Almestrone (INN), also known as 7α-methylestrone, is a synthetic, steroidal estrogen which was synthesized in 1967 but was never marketed. It is used as a precursor in the synthesis of several highly active steroids.
A progestogen ester is an ester of a progestogen or progestin. The prototypical progestogen is progesterone, an endogenous sex hormone. Esterification is frequently employed to improve the pharmacokinetics of steroids, including oral bioavailability, lipophilicity, and elimination half-life. In addition, with intramuscular injection, steroid esters are often absorbed more slowly into the body, allowing for less frequent administration. Many steroid esters function as prodrugs.
A steroid ester is an ester of a steroid. They include androgen esters, estrogen esters, progestogen esters, and corticosteroid esters. Steroid esters may be naturally occurring/endogenous like DHEA sulfate or synthetic like estradiol valerate. Esterification is useful because it is often able to render the parent steroid into a prodrug of itself with altered chemical properties such as improved metabolic stability, water solubility, and/or lipophilicity. This, in turn, can enhance pharmacokinetics, for instance by improving the steroid's bioavailability and/or conferring depot activity and hence an extended duration with intramuscular or subcutaneous injection.
Estrofurate, also known as 17α-(3-furyl)-estra-1,3,5(10),7-tetraene-3,17-diol 3-acetate, is a synthetic, steroidal estrogen that was synthesized in 1967 and studied in the late 1960s and early 1970s but was never marketed. It is a relatively weak estrogen in bioassays.
Etamestrol (INN), or eptamestrol, also known as 7α-methyl-19-nor-17α-pregna-1,3,5(10)-trien-20-yne-1,3,17-triol 1,3-dibenzoate, is a synthetic, steroidal estrogen described as an ovulation inhibitor that was synthesized in 1979 but was never marketed.
Clomestrone, also known as 16α-chloroestrone 3-methyl ether, is a synthetic, steroidal, weak estrogen derived from estrone and used as an anticholesterolemic agent in the treatment of atherosclerosis. It is said to have beneficial effects on serum lipid profiles while producing minimal feminization, though some estrogenic side effects, including breast tenderness, loss of libido, and fatigue or avolition, were observed in most patients in clinical studies. The drug is a close analogue of mytatrienediol, and the two estrogens have similar drug profiles. Clomestrone was described in the literature in 1958 and introduced for medical use shortly thereafter.
Prolame, also known as 17β-( amino)estradiol, is a synthetic, steroidal estrogen and a 17β-aminoestrogen with anticoagulant effects that was first described in 1985 but was never marketed.
Ethinylestradiol benzoate, or 17α-ethynylestradiol 3-benzoate, is a synthetic estrogen and estrogen ester – specifically, the C3 benzoate ester of ethinylestradiol – which was first described in the late 1930s and was never marketed.
Estrone methyl ether, or estrone 3-methyl ether, is a synthetic estrogen and estrogen ether – specifically, the C3 methyl ether of estrone – which was never marketed. It has been used to synthesize mestranol.
Conjugated estriol, sold under the brand names Progynon and Emmenin, is an estrogen medication which was previously used for estrogen-type indications such as the treatment of menopausal symptoms in women. The term specifically refers to formulations of estriol conjugates which were manufactured from the estrogen-rich urine of pregnant women and were used as medications in the 1920s and 1930s. Conjugated estriol is analogous to and was superseded by conjugated estrogens, which is manufactured from the urine of pregnant mares. Conjugated estriol was among the first forms of pharmaceutical estrogen to be used in medicine. It was taken by mouth.
