Evaluation of liposomes as drug carriers into the skin by one-dimensional EPR imaging

Abstract One-dimensional electron paramagnetic resonance imaging (1D-EPRI) was used to evaluate quantitatively the influence of the size and composition of liposomes on the translational mobility of liposome-entrapped charged hydrophilic molecules (ASL) into the skin. It was found that only ASL molecules entrapped in small unilamellar vesicles (SUV) or reverse-phase evaporation vesicles (REV) from ‘fluid’ phospholipids (egg or soya lecithin and phosphatidylserine) can diffuse, while free ASL or ASL entrapped in the multilamellar vesicles (MLV) or REV from ‘solid’ phospholipids (dipalmitoyl lecithin/dipalmitoylglycerol) do not penetrate. The 1D-EPRI method was found to be useful for the study of diffusion of drugs into the skin.