To analyse the residual crystallinity of the samples without applying additional thermal energy, PXRD measurements of the extrudates were carried out (Figure ). The potential reflexes from residual crystallinity peaks are highlighted, and residual crystallinity is minute, but not entirely absent, although it is difficult to determine these peaks due to the low signal to noise ratio within the PXRD patterns. The resulting thermal properties of the neat polymer and the polymer:IND extrudates (Table ), indicate an influence of drug loading on the Tg of the extrudates as it increases with higher drug concentration. The Tg for each sample was also calculated using the Gordon Taylor equation (Equation ) and the calculated values are lower than the experimentally obtained ones for all polymer:IND ratios. This positive deviation from the theoretical Tg could be attributed to a higher number and strength of interactions between the polymer and the drug in the mixture than in the individual components due to for example hydrogen bonding between the amide moieties in the polymer and the carboxylic acid of IND. Table . Thermal properties of the neat polymer and drug, as well as the extrudates with different polymer:IND ratios. Tg 1 was taken from the 2 nd and 3 rd heating cycles of DSC measurements (Figure ). The Tm and ΔHf was taken from the 1 st heating cycle for IND and from 2 nd and 3 rd heating cycle for the polymer. Tg 2 was calculated by Gordon Taylor equation.