Hydroxyestrone diacetate (brand names Colpoginon, Colpormon, Hormobion, Hormocervix) (former developmental code name RD-310), or 16α-hydroxyestrone diacetate, also known as 3,16α-dihydroxyestra-1,3,5(10)-trien-17-one 3,16α-diacetate, is a synthetic, steroidal estrogen which has been marketed in France, Spain, Brazil, and Argentina.[1] [2] It is a derivative of 16α-hydroxyestrone with an acetate esters attached at the C3 and C16α positions.