Interaction of hydrated α-galactosylceramide with nonionic surfactants and formation of dispersions including gel phases

Hydrated α-Galactosylceramide (α-GalCer) has a high gel to liquid crystalline phase transition temperature and forms a gel phase at room temperature, which separates from an excess aqueous medium. In this study, α-GalCer was dispersed into the aqueous medium by high-pressure emulsification with nonionic surfactants. Using Pluronic, stable dispersions with a hydrodynamic diameter of ca. 200 nm were obtained. Small-angle and wide-angle X-ray diffraction from the dispersion showed patterns similar to those of the hydrated α-GalCer indicating the formation of the gel-containing nanoparticles. Differential scanning calorimetry (DSC) also revealed the existence of gel phases in the dispersion. However, the particles aggregated when Tween was used as a stabilizer. On the other hand, the solubility of α-GalCer was higher in Tween micelles than Pluronic micelles. DSC results suggested that Pluronic was less compatible with the α-GalCer gel phase than Tween, which was related to the stability of the dispersions and solubility of α-GalCer in micelles.