NMR study of the sorption behavior of benzyl alcohol derivatives into sonicated and extruded dioctadecyldimethylammonium chloride (DODAC) dispersions: the relevance of membrane fluidity

The sorption behavior of three benzyl alcohol derivatives with different hydrophobicities into sonicated and extruded DODAC dispersions has been studied using NMR spectroscopy and NMR diffusometry. We show that there is an increased sorption into a sonicated dispersion below the phase-transition temperature (T(m)) as compared to an extruded dispersion. This may be explained by the incomplete lipid chain freezing of charged lipids as a result of the sonication process. Around T(m), a sorption maximum is found that is attributed to the high bilayer disorder under this condition. In addition, a sorption increase and a fluidizing effect at increasing benzyl alcohol derivative concentrations are observed that provide additional evidence for the relevance of the bilayer fluidity on the sorption of hydrophobic components.