## 3 Results and Discussion
### Stability and Thermal Profile  
The thermal behaviour of the raw materials was analysed using DSC and TGA, carried out simultaneously (STA) and alone (DSC). The APIs were the raw materials with the lower thermal stability (other raw materials thermograms in the Supplementary Materials). STA thermograms of esomeprazole Mg 2H\({}_{2}\)O and 3H\({}_{2}\)O (Figure 3a,b) showed a small loss in sample mass of 5.19% and 7.73%, respectively, immediately after the heating started. These effects resulted from water loss by evaporation. In addition, at approximately 180 \({}^{\circ}\)C, a thermic phenomenon occurred in both samples, indicating a physical and/or a chemical transformation at that temperature. These recorded phenomena correspond to a fusion (endothermic peak), maximum at temperatures ranging from 149 \({}^{\circ}\)C to 165 \({}^{\circ}\)C, followed by a decomposition of the material (exothermic peak). In this sense, the two forms of hydration of esomeprazole Mg have shown thermal stability up to a temperature of around 180 \({}^{\circ}\)C. The STA thermogram of ondansetron (Figure 3c) presented an initial endothermic phenomenon, which was also observed in the analysis of the other raw materials, with a mass loss due to the evaporation of water. At a temperature of around 180 \({}^{\circ}\)C, an endothermic phenomenon compatible with fusion was noted, followed by endothermic and exothermic phenomena associated with a mass loss of 72.02%, compatible with material decomposition, indicating that ondansetron was stable up to 220 \({}^{\circ}\)C. The STA thermograms of other raw materials are presented in the Supplementary Materials (Supplementary Figures S2, S4, S6 and S8). The STA thermogram of the MCC showed an endothermic phenomenon (heat absorption) that occurred at approximately 300 \({}^{\circ}\)C together with a mass loss of 82.65%, suggesting that the material was stable up to this temperature. The different PVP materials demonstrated stability up to a temperature of 400 \({}^{\circ}\)C. Below this temperature, samples did not show any thermal phenomena compatible with physical or chemical changes of the material. Concerning PVA Mw30, there was a pronounced mass loss (89.26%) at temperatures above 300 \({}^{\circ}\)C. The onset of the endothermic phenomenon at this temperature corresponds to the loss of thermal stability of the raw material, suggesting the degradation of the sample. Table 3 displays the melting temperatures (measured at peak temperature) and thermal stability of raw materials. In summary, the melting temperature for crystalline or partially crystalline ingredients ranged from 149 \({}^{\circ}\)C (esomeprazole Mg 3H\({}_{2}\)O) and 338 \({}^{\circ}\)C (MCC), and the decomposition temperature ranged from 180 \({}^{\circ}\)C (esomeprazole Mg 3H\({}_{2}\)O) and 400 \({}^{\circ}\)C (all PVPs). The thermal behaviour of esomeprazole Mg by the DSC was depicted in the study by [PERSON] et al. [38], in which the established melting temperature of esomeprazole magnesium was 175 \({}^{\circ}\)C. The material used in this study (both di and tri hydrate) presented lower melting temperatures. As stated before, crystallinity (as determined by XRD) was around 75%, resulting in a lower melting temperature and a wider melting interval. In fact, when compared to ondansetron (99% crystalline), esomeprazole presented wider melting  
Figure 2: X-RPD diffractograms of PVP K17 (**a**) and Ondansetron (**b**). peaks. In the study carried out by [PERSON] and [PERSON] [39], it is reported the thermal analysis of ondancetron, evidencing a phenomenon corresponding to melting with a peak at 183 \({}^{\circ}\)C, is compatible with the one observed in this study. The thermal stability of MCC was evaluated by others [40] that reported a decomposition temperature of approximately 300 \({}^{\circ}\)C, compatible with the one obtained in this study.