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The three different solid forms of dexktoprofen trometamol (DK-T_A, DK-T_B, and DK-T_2H2O) have been studied by using X-ray diffraction and calorimetric methods. In the molecular and crystal structure of DK-T_A, the thermodynamically stable form used in the tablets production process, all the potential H-bond donors and acceptors of each trometamol cation are involved in strong H-bonds which hold together the cations as well as the dexketoprofen/trometamol ionic pairs. The dihydrate species is quickly formed starting from DK-T_A apparently without the formation of an amorphous phase, and the process is fully reversible. In addition, the two solids have comparable crystal density (cell parameters and space group of the resulting hydrate were determined by X-ray powder diffraction). We speculate that the anhydrous and hydrate crystal architectures did not suffer upon the hydration/dehydration process and that the hydrate form belongs to the class of the channel hydrates and most probably is a planar hydrate. Finally, the unit cell parameters and space group were determined also for the metastable DK-T_B solid form.

The metoprolol fumarate (MF) salt has been characterized by a combined use of powder X-ray diffraction (PXRD), variable temperature PXRD (VT-PXRD), and differential scanning calorimetry. Its molecular and crystal structure, as determined from PXRD data, has been thoroughly compared to those of the analogous tartrate (MT-o) and succinate (MS-m) salts. Moreover, Hirshfeld surface analysis and graph sets analysis have been performed to achieve insights into the intermolecular interactions. Despite their evident similarities at the molecular level, the three salts behave differently upon temperature variation: MF expands/contracts anisotropically (as MS-m), but the melt takes 3 days to recover the starting crystalline phase (as MT-o). A rationale for this behavior is provided based on their crystal arrangements.

MEN11282 (1) is a precursor of nepadutant (MEN11420), a potent and selective antagonist at the human tachykinin NK-2 receptor (hNK-2), that has been evaluated in clinical trials for different therapeutic indications. Three crystalline forms of 1 were identified and characterized by both single crystal and powder X-ray diffraction (SCXRD and XRPD): a monohydrate (1·H2O, SCXRD) and two different anhydrous forms, namely, 1_α and 1_β (XRPD). Because of the relevance that the solid form of a substance of pharmaceutical interest plays during the manufacturing process, variable temperature powder X-ray diffraction (VT-XRPD) in conjunction with differential scanning calorimetry were used to investigate the behavior of the different solid forms of 1. The rationale for the dehydration and hydration process involving 1·H2O and 1_α and the stability of 1_β toward water uptake is provided based on their crystal packings.

A combined X-ray diffraction (XRD), solid state nuclear magnetic resonance (SSNMR), differential scanning calorimetry (DSC), and modeling approach has been applied to study the solid–solid transiti...