Abstract
Small and wide angle high energy x-ray scattering experiments were performed upon cooling itraconazole from the melt to investigate the structural origin of the two transitions at 74oC and 90oC observed in DSC measurements. Slight changes to the main WAXS peak at Q=1.33 Å-1 were observed at 90oC and are found to be inter-molecular in nature, suggesting an isotropic liquid to isotropic glass transition. This finding was supported by complementary wide angle neutron scattering measurements. For temperatures at and below 74oC two strong rings appear in the 2D-SAXS pattern at Q=0.24 Å-1 and 0.43 Å-1. The SAXS spectra were further deconvoluted into sharp and broad components. A narrowing of the broad component is associated with only minor changes in the packing arrangements of the itraconazole molecules below 90oC, while the appearance of the sharp component below 74oC is attributed to the formation of a polydomain lamellar phase.
