Аннотация:Small angle neutron scattering (SANS), neutron diffraction and X-ray powder diffraction were used to investigate influence of N-stearoylphytosphingosine (CER[NP]) and α-hydroxy-N-stearoylphytosphingosine (CER[AP]) on the internal structure and hydration of DMPC membrane in fully and partly hydrated states at T=30°C. Application of Fourier analysis for diffraction data and model calculations for the SANS data evidence that addition of both CER[NP] and CER[AP] in small concentrations promotes significant changes in the organization of DMPC bilayers, such as the increase of the hydrophobic core region. SANS data evidences a decrease in the average radius and polydispersity of the vesicles that can be ascribed to hydrogen bonds interactions that favor tight lipid packing with a compact, more rigid character.