Characterization of an inclusion complex of, 7-dehydrocholesterol and cyclodextrin

7-Dehydrocholesterol (7-DHC) plays an important role in the biosynthesis of vitamin D. It is virtually insoluble in water, in which its manipulation is difficult, but the problems may be alleviated by cyclodextrin inclusion. Cyclodextrins are known to form inclusion complex with many kinds of hydrophobic compounds because their molecular structure generates a hydrophilic exterior surface and a hydrophobic cavity interior. The purpose of this study was to characterize inclusion complex of 7-dehydrocholesterol with cyclodextrin (hydroxypropyl-β-cyclodextrin, HPβCD). The inclusion complex showed good solubility in contrast to physical mixture. The inclusion efficiency determined by HPLC analysis was 83.72%. Additionally, the inclusion complex was characterized by UV–vis spectrophotometry, Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). These results demonstrated that 7-dehydrocholesterol with hydroxypropyl-β-cyclodextrin formed an inclusion complex.