*3.2. Thermal Analysis*

The DSC profiles of the pristine PZQ showed a strong endothermic peak at 144 ◦C, according to previous work [18] (Figure 2). The DSC profile of SEP and VHS indicated broad endothermic peaks in the range 50–90 ◦C due to the evaporation of water (Figure 2).

**Figure 2.** Differential Scanning Calorimetric (DSC) profiles of sepiolite and interaction products of sepiolite (**a**) and montmorillonite and interactions products of montmorillonite (**b**).

In Figure 2a, the PZQ–SEPet and PZQ–SEPac interaction product profiles presented a very low-intensity peak corresponding to the melting of the drug. This indicates that a small amount of PZQ crystallized outside of the channels in the interstitial spaces of solid. Specifically, the enthalpy of the endothermic peak (ΔH) at 144 ◦C was 3.9 and 1.3 J g−<sup>1</sup> respectively, which can be compared with the enthalpy of 90.4 J g−<sup>1</sup> of the melting peak of the pristine drug. Therefore, the ΔH melting (PZQ–SEP)/ΔH melting (pure PZQ), was 4.3% in PZQ–SEPet and 1.4% in PZQ–SEPac. On the contrary, in the PZQ–SEPdic profile, the complete disappearance of the melting peak of the drug was observed.

The DSC curves of PZQ–VHS interaction products showed the water evaporation of the raw materials until 100 ◦C, and no melting peak of PZQ was observed in all interaction products (PZQ–VHSet, PZQ–VHSdic and PZQ–VHSac) (Figure 2b).

Therefore, the lack of the peak of PZQ in the interaction products was observed probably due to the amorphization and no recrystallization of the drug after the complete interaction with the clay. This justified the lack of drug reflections in the PZQ–clay powder XRD patterns. Previous studies found similar results [21,31,33].

In summary, the appearance of a small peak of the drug in some of the samples is practically insignificant and its appearance or non-appearance depends on the variability of production, compared with previous results [33]. Therefore, in drug–clay interaction products, a practically complete amorphization of the drug occurs.

According to the first weight loss of the TGA profile, absorbed water of VHS and SEP accounted for 8% and 10% *w*/*w*, respectively (Figure 3). Zeolitic water loss of SEP occurred at 250–350 ◦C [45].

**Figure 3.** Thermogravimetric Analysis (TGA) profiles of the studied samples with sepiolite (**a**) and with montmorillonite (**b**).

In the interaction products both with sepiolite and montmorillonite, thermal decomposition of the drug resulted in weight losses in the range between 200 and 400 ◦C, corroborating the adsorption of the PZQ in these mineral solids (Figure 3).
