New Polymorph of Dehydroepiandrosterone Obtained via Cryomodification

A new anhydrous polymorph of dehydroepiandrosterone
(DHEA) is detected
in cryomodified powder samples and designated as form VII. The crystal
structure of form VII is determined from multiphase X-ray powder diffraction
(XRPD) data. Additionally, the unknown crystal structures of anhydrous
form III and the new monohydrated DHEA form designated as form S5
are also determined from multiphase XRPD data. To validate the crystal
structures III, VII, and S5, energy minimization with dispersion-corrected
density functional theory is performed in VASP. An extended list of
the DHEA forms with the known crystal structures, which now covers
anhydrous forms I, II, III, VI, and VII and solvated forms S1, S2,
S4 and S5, allows quantification of DHEA solid-state transformations
to be carried out.