## 3 Results and Discussion
### Characterization of Drug Loaded PEO  
Representative SEM images of the drug-loaded PEO are shown in Figure 6. It can be suggested that appointment is highly dispersed, almost \"fused\" in the polymer matrix, as only some very small particles in the form of spheres (indicated by white arrows) lower than 0.25 \(\upmu\)m in size could be identified in the SEM images. FTIR spectroscopy is a very useful and widely used method to examine any possible interactions between polymers and \"dissolved\" drugs or possible structural changes in either of the blend  
Figure 5: DSC curves of pure PEO and PEO/5 wt % clay (PEO_5 Cloisite-Na\({}^{+}\)) nanocomposite. Figure 6: SEM images of drug-loaded PEO with 10 wt % APR (PEO_10 Aprep) (left) and 20 wt % APR (PEO_20 Aprep) (right). components. The most probable type of bonding that is expected to happen between PEO and APR is hydrogen bonding between the amine group of APR and the oxygen or hydroxyl end groups (-OH groups) of PEO. However, as can be seen from the FTIR spectrum of the pure APR compound (Figure 7a), the respective peak at 1605 cm\({}^{-1}\) (N-H bending) is of very low intensity due to the relative low abundance of these groups in the APR molecule. Thus, it is difficult to identify and discuss the presence of absence of this peak in the PEO/APR formulations (spectra also included in Figure 7a). Other characteristic peaks of APR can be identified at 3167 cm\({}^{-1}\) (secondary N-H stretching), 1704 cm\({}^{-1}\) (amide C=O stretch) [62], and 1509 cm\({}^{-1}\) (C=C stretch). Peaks at 1289 cm\({}^{-1}\), 1169 cm\({}^{-1}\), and 1069 cm\({}^{-1}\) are due to C-O stretching [63], while peaks at 1129 cm\({}^{-1}\), 1140 cm\({}^{-1}\), and 1117 cm\({}^{-1}\) correspond to C-F stretching. The presence of the band at 1140 cm\({}^{-1}\) indicates that the APR was a form II polymorph, as reported in literature [64]. The FTIR spectra of the APR-loaded PEO exhibited all the characteristic peaks of pristine PEO (Figure 7a), thus indicating the retention of its structure. Furthermore, the peak at 1704 cm\({}^{-1}\) verifies the presence and structural integrity of APR in the PEO/APR solid dispersions. Since this peak remains at the same position as in neat drug, any interactions with PEO should be excluded. The XRD patterns of pure APR and PEO and the APR-loaded PEO are also shown in Figure 7b. Pure APR exists in two crystal polymorphs: form I and II. Each form exhibits different characteristic reflections. In accordance with the data reported in the literature, it can be seen that both forms can be identified in the drug used in this study, that is, peaks at about 12.7\({}^{\circ}\), 16.7\({}^{\circ}\), 20.0\({}^{\circ}\), and 23.0\({}^{\circ}\) corresponding to form I and peaks at about 18.2\({}^{\circ}\) and 21.0\({}^{\circ}\) attributed to form II [64; 65]. Some of these peaks can also be seen in the pattern of the 10 and 20 wt % APR-loaded PEO sample, indicating that the drug is dispersed in crystalline, or better still, in semicrystalline form inside the polymer matrix. This was expected since melt mixing was taking place at a lower temperature than the melting point of the drug, in order to avoid drug decomposition. Also, this is very common when semicrystalline polymers are used for the preparation of drug solid dispersions [66; 67; 68]. This is ought to improve  
Figure 7: FTIR spectra (**a**) and XRD patterns (**b**) of pure appointment (APR), pure PEO, and PEO loaded with 5, 10, and 20 wt % APR (PEO_5 Aprep, PEO_10 Aprep, and PEO_20 Aprep, respectively). polymer microstructure and especially that of existing polymer crystal which acts as a nucleating agent for drug crystallization. However, as can be seen, the intensity of drug peaks is very small, which is a clear indication that their crystallinity was reduced in solid dispersions. The absence of the APR peaks in the patterns of the composites with the lower drug loading can be justified based on the relatively lower absolute crystallinity of the drug compared to that of the PEO and the lower loading degree (5 wt %).