Estradiol benzoate

Estradiol benzoate (INN; brand names Agofollin, Diffolisterol, Progynon-B, many others), or oestradiol benzoate (BAN), is a synthetic ester, specifically the 3-benzoyl ester, of the natural estrogen, estradiol. It was the first form of estrogen to be marketed, patented by Schering-Kahlbaum in 1936 in an oil preparation for injectable use and introduced later that year as Progynon-B. Though it is still in widespread use today, it has been mostly superseded by newer forms of estradiol with improved pharmacokinetics that require less frequent administration such as estradiol cypionate and estradiol valerate.