Physicochemical characterizations of safranal-β-cyclodextrin inclusion complexes prepared by supercritical carbon dioxide and conventional methods

In this work, inclusion complexes of safranal with β-cyclodextrin (β-CD) were prepared using supercritical carbon dioxide (SC-CO₂) as well as kneading (KN), co-evaporation, and sealed heating conventional methods. Prepared complexes were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction, scanning electron microscopy and proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Effect of preparation method on the yield of inclusion complexes was also investigated. The SC-CO₂ method was found to be the most effective preparation technique with the advantage of not using organic solvents. Effects of temperature and pressure on the properties of complexes prepared by SC-CO₂ were also investigated. FT-IR and ¹H-NMR results confirmed the formation of safranal-β-CD inclusion complexes prepared using all the above mentioned preparation techniques. Phase solubility and dissolution measurements revealed a ''B_s'' type solubility with an apparent stability constant (K_s) of 39.69 M^-1. Initial aqueous solubility of safranal was enhanced by about 35 % upon complex formation with β-CD. Studies on dissolution rate showed a faster dissolution rate of inclusion complexes compared to pure safranal.