*2.6. Fourier Transform Infrared Analysis*

The FTIR absorption spectra of the individual samples of GCPPE, HP-*β*-CD, the inclusion complex (IC) (GCPPE+HP-*β*-CD+MD), and the physical mixture were analyzed separately. The physical mixture (PM) (GCPPE/HP-*β*-CD/MD) was prepared by accurately weighing HP-*β*-CD (100 mg), GCPPE (100 mg), and MD (20 mg), which were ground in a mortar until the mixture was homogeneous. The resulting physical mixture was immediately analyzed by FTIR-ATR.

The FTIR spectra were recorded using a Bruker Alpha T FTIR (Bruker, Germany) spectrophotometer equipped with a diamond attenuated total reflectance (ATR) unit. The 32 scans were acquired over a spectral range of 4000–500 cm−<sup>1</sup> with a resolution of 4 cm−<sup>1</sup> [22,23]. All spectra were acquired and processed using the OPUS 7.0 software.
