XRD-CT of all the samples measured indicates a significant change to the structure of the components of the tablets (Figure ). Firstly, both forms of crystalline glycolide deteriorated over the course of a month as there was no indication of either Form in the tablet. Secondly, the peak height and sharpness of the diffraction pattern of an unknown phase were both enhanced in the aged samples indicating increased formation of this crystalline solid during storage, as seen in Figure for two different compaction pressures. Interestingly, additional diffraction patterns isolated from parts of the tablet cannot be identified as any of the known forms of any of the components (Figure ).