It is the aim of the proposal is to perform small angle neutron scattering (SANS) studies combined with contrast variation to determine the size and structure of the phospholipid-stabilised microemulsions prepared using a dispese phase of a pharmaceutically acceptable oil in a polar, non-aqueous solvent. Of particular interest is the effect of the structure of the polar, non-aqueous solvent on the size and structure of the resulting microemulsion. Due to refractive index matching of the various microemulsion components, it is not possible to determine size or shape using light scattering. Consequently neutron studies are essential to study microemulsion formation in these water-free systems. The current studies will inform the future development of these interesting and potentially important delivery systems.