Creatine: Polymorphs Predicted and Found

Hydrate and anhydrate crystal structure
prediction (CSP) of creatine
(CTN), a heavily used, poorly water-soluble, zwitterionic compound,
has enabled the finding and characterization of its anhydrate polymorphs,
including the thermodynamic room temperature form. Crystal structures
of the novel forms were determined by combining laboratory powder
X-ray diffraction data and ab initio generated structures. The computational
method not only revealed all experimental forms but also predicted
the correct stability order, which was experimentally confirmed by
measurements of the heat of hydration.