Estradiol valerate (brand name: Delestrogen) is used as a hormone replacement therapy for menopause symptoms and for treating advanced prostate cancer. Commercial estradiol 17β valerate crystallizes in the monoclinic space group P2₁ with a = 7.36787(3), b = 19.84900(6), c = 13.99395(10) Å, β = 90.6845(5)°, V = 2046.398(18) ų, and Z = 4. A reduced cell search in the Cambridge Structural Database (Groom et al., Reference Groom, Bruno, Lightfoot and Ward2016) yielded a previously reported crystal structure above 251 K (Ellena et al., Reference Ellena, de Paula, de Melo, da Silva, Bezerra, Venâncio and Ayala2014). In this work, the sample was ordered from U.S. Pharmacopeial Convention (USP), Lot #M0M476 and analyzed as received. The room-temperature crystal structure was refined using synchrotron (λ = 0.414163 Å) powder diffraction data, density functional theory, and Rietveld refinement techniques. The diffraction data were collected on beamline 11-BM at the Advanced Photon Source, Argonne National Laboratory. Figure 1 shows the powder X-ray diffraction pattern of the compound. The crystal structure contains two independent chains of O–H···O hydrogen bonds along the c-axis. Weak C–H···O hydrogen bonds also contribute to the crystal energy. The conformation of the valerate side chain in one molecule (C46–C51) differs from that reported by Ellena et al. (Reference Ellena, de Paula, de Melo, da Silva, Bezerra, Venâncio and Ayala2014). The pattern is included in the Powder Diffraction File as entry 00-066-1612.

Figure 1. (Colour online) Powder X-ray diffraction pattern of estradiol 17β valerate.