estradiol phosphate estradiol phosphate estradiol phosphate, or estradiol 17β-phosphate, also known as estra-1,3,5(10)-triene-3,17β-diol 17β-(dihydrogen phosphate), is an estrogen which was never marketed. it is an estrogen ester, specifically an ester of estradiol with phosphoric acid, and acts as a prodrug of estradiol in the body. it is rapidly cleaved by phosphatase enzymes into estradiol upon administration. estradiol phosphate is contained within the chemical structures of two other estradiol esters, polyestradiol phosphate (a polymer of estradiol phosphate) and estramustine phosphate (estradiol 3-normustine 17β-phosphate), both of which have been marketed for the treatment of prostate cancer. structural properties of selected estradiol esters estrogenstructureester(s)relativemol. weightrelativee2 contentblog pc position(s)moiet(ies)typelengtha estradiol––––1.001.004.0 estradiol acetatec3ethanoic acidstraight-chain fatty acid21.150.874.2 estradiol benzoatec3benzenecarboxylic acidaromatic fatty acid– (~4–5)1.380.724.7 estradiol dipropionatec3, c17βpropanoic acid (×2)straight-chain fatty acid3 (×2)1.410.714.9 estradiol valeratec17βpentanoic acidstraight-chain fatty acid51.310.765.6–6.3 estradiol benzoate butyratec3, c17βbenzoic acid, butyric acidmixed fatty acid– (~6, 2)1.640.616.3 estradiol cypionatec17βcyclopentylpropanoic acidaromatic fatty acid– (~6)1.460.696.9 estradiol enanthatec17βheptanoic acidstraight-chain fatty acid71.410.716.7–7.3 estradiol dienanthatec3, c17βheptanoic acid (×2)straight-chain fatty acid7 (×2)1.820.558.1–10.4 estradiol undecylatec17βundecanoic acidstraight-chain fatty acid111.620.629.2–9.8 estradiol stearatec17βoctadecanoic acidstraight-chain fatty acid181.980.5112.2–12.4 estradiol distearatec3, c17βoctadecanoic acid (×2)straight-chain fatty acid18 (×2)2.960.3420.2 estradiol sulfatec3sulfuric acidwater-soluble conjugate–1.290.770.3–3.8 estradiol glucuronidec17βglucuronic acidwater-soluble conjugate–1.650.612.1–2.7 estramustine phosphatedc3, c17βnormustine, phosphoric acidwater-soluble conjugate–1.910.522.9–5.0 polyestradiol phosphateec3–c17βphosphoric acidwater-soluble conjugate–1.23f0.81f2.9g footnotes: a = length of ester in carbon atoms for straight-chain fatty acids or approximate length of ester in carbon atoms for aromatic fatty acids. b = relative estradiol content by weight (i.e., relative estrogenic exposure). c = experimental or predicted octanol/water partition coefficient (i.e., lipophilicity/hydrophobicity). retrieved from pubchem, chemspider, and drugbank. d = also known as estradiol normustine phosphate. e = polymer of estradiol phosphate (~13 repeat units). f = relative molecular weight or estradiol content per repeat unit. g = log p of repeat unit (i.e., estradiol phosphate). sources: see individual articles. not to be confused with polyestradiol phosphate. estradiol phosphateclinical dataother namesestradiol 17β-phosphate; estra-1,3,5(10)-triene-3,17β-diol 17β-(dihydrogen phosphate); 3-hydroxyestra-1,3,5(10)-trien-17β-yl phosphatedrug classestrogen; estrogen esteridentifiers iupac name phenanthren-17-yl] dihydrogen phosphate cas number4995-43-1 ypubchem cid66435chemspider10043883uniiskl7pdp588chemblchembl1642763comptox dashboard (epa)dtxsid6045086 chemical and physical dataformulac18h25o5pmolar mass352.367 g·mol−13d model (jsmol)interactive image smiles c12cc3(1cc2op(=o)(o)o)ccc4=c3c=cc(=c4)o inchi inchi=1s/c18h25o5p/c1-18-9-8-14-13-5-3-12(19)10-11(13)2-4-15(14)16(18)6-7-17(18)23-24(20,21)22/h3,5,10,14-17,19h,2,4,6-9h2,1h3,(h2,20,21,22)/t14-,15-,16+,17+,18+/m1/s1key:bbwxlckryrqqpl-zbrfxrbcsa-n