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.
Estriol succinate
Estriol succinate, also known as estriol disuccinate or as estriol 16α,17β-di(hydrogen succinate), is a synthetic estrane steroid and a derivative of estriol. It is specifically the C16α and C17β disuccinate ester of estriol. The medication is provided both as estriol succinate and as estriol sodium succinate, the sodium salt. Other marketed estriol esters besides estriol succinate include estriol acetate benzoate and estriol tripropionate, whereas estriol dihexanoate, estriol dipropionate, and estriol triacetate are estriol esters that were never marketed. Quinestradol is an estriol ether and has also been marketed. Polyestriol phosphate is an ester of estriol in the form of a polymer, and was previously marketed.