Along with estradiol valerate (1954) and estradiol benzoate (1933), estradiol cypionate has become one of the most commonly used esters of estradiol.When estradiol cypionate was to be combined with medroxyprogesterone acetate as a once-a-month injectable contraceptive, there was a problem in that estradiol cypionate was prepared as an oil solution while medroxyprogesterone acetate was used as a microcrystalline aqueous suspension. This issue was resolved by switching to a microcrystalline aqueous suspension in the case of estradiol cypionate, allowing it to be combined with medroxyprogesterone acetate in a single suspension. As a result, single-drug preparations of estradiol cypionate are oil solutions, while the combination of estradiol cypionate and medroxyprogesterone acetate are microcrystalline aqueous suspensions. Society and culture
Generic names
Estradiol cypionate is the generic name of the drug and its INN and USAN. It is also known as estradiol cyclopentylpropionate (ECP). Brand names
Estradiol cypionate has been marketed under the brand names Cicloestradiolo, D-Est, depGynogen, Depo-Estradiol, Depoestra, Depofemin, Depogen, Dura-Estrin, E-Cypionate, E-Ionate, Estradep, Estro-Cyp, Estrofem, Estroject, Estromed-PA, Estronol, Femovirin, Neoginon Depositum, Oestradiol-Retard, Pertradiol, Spendepiol, and T-E Cypionate, among others. Availability
Estradiol cypionate is available in the United States. It was previously marketed in Spain and Italy, but was discontinued in these countries and is no longer available in Europe. Estradiol cypionate has mostly been used in the United States, similarly to testosterone cypionate, with both of these medications having been developed by Upjohn, an American pharmaceutical company. Besides the United States, estradiol cypionate has been marketed in France, Germany, Italy, Spain, and Japan, among other countries.
The affinity of estradiol valerate for the estrogen receptor has been reported to be 50 times less than that of estradiol, and estradiol valerate and estradiol cypionate have been found to possess similar affinity for the estrogen receptor. Both estradiol cypionate and estradiol valerate are rapidly cleaved into estradiol in the body, and estradiol valerate has been found to be unable to reach target tissues in any concentration of significance. As such, estradiol valerate is regarded as essentially inactive in terms of estrogenic effect itself, acting solely as a prodrug to estradiol, and estradiol cypionate is described as a prodrug of estradiol similarly. Estradiol cypionate is of about 46% higher molecular weight than estradiol due to the presence of its C17β cypionate ester, and contains about 69% of the amount of estradiol by weight. Because estradiol cypionate is a prodrug of estradiol, it is considered to be a natural and bioidentical form of estrogen. Effects on liver protein synthesis
A study compared the combination of 5 mg estradiol cypionate and 25 mg medroxyprogesterone acetate as a combined injectable contraceptive (which has been associated with peak estradiol levels of around 300 pg/mL) with an ethinylestradiol-containing combined birth control pill and found that whereas the birth control pill produced significant changes in coagulation parameters, there were no significant prothrombotic effects of the combined injectable contraceptive on levels of fibrinogen, factors VII and X, plasminogen, or the activated prothrombin time.