The tablets were mounted onto a standard Huber goniometer in two orientations to provide lateral and longitudinal cross sections (Figure ) using the XRD-CT method; full experimental details are included in the SI. Phase identification of the reconstructed XRD-CT datasets was performed on summed global patterns using X'Pert HighScore Plus, with the phases identified as being glycolide Form I (CSD refcode NAHNIT01), glycolide Form II (CSD refcode NAHNIT02), microcrystalline cellulose and an unknown phase, later identified to be 2-(2-hydroxyacetoxy)acetic acid. Magnesium stearate was added at a low level of 1% wt. in the powder blend so its presence in the tablets was not significant. Unique reflections were identified and used to generate the spatial distribution maps of each phase.