Preparation and properties of phytosterols with hydroxypropyl β-cyclodextrin inclusion complexes

In order to enhance the solubility and bioavailability of phytosterols (PS), cyclodextrin-PS (CD-PS) inclusion complexes were prepared and the properties of PS-beta-cyclodextrin (PS-beta-CD) and the inclusion mechanism of its derivative hydroxypropyl beta-cyclodextrin (PS-HP-beta-CD) in solution were also evaluated. The effects of crucial parameters on cyclodextrin-sterol inclusion efficiency were optimized, including solvent type, beta-CD/PS molar ratio, temperature, PS content and reaction time; 92-98 % inclusion efficiency was achieved under the conditions of HP-beta-CD/PS ratio 3:1-4:1, PS concentration 15-20 mM, temperature 50-55 A degrees C, reaction time 12 h. For beta-CD host, butanol was a good solvent for PS inclusion reaction. The properties of CD-PS inclusion complexes were characterized by differential scanning calorimetric, scanning electron microscopy, UV-Vis scanning spectrophotometer (UV-Vis) and fourier transform infrared spectroscopy (FT-IR), which demonstrated that there are intermolecular hydrogen bonds between PS and HP-beta-CD in inclusion complex, resulting in the formation of amorphous form. To clarify the mechanism of the increase in the solubility and bioactivity of HP-beta-CD-PS inclusion complexes, the structure of CD as well as the interaction of the HP-beta-CD-PS inclusion formation was elucidated. The conclusions indicated that PS-HP-beta-CD showed higher water solubility with greater solubilizing and complexing capabilities than PS-beta-CD and PS itself.