Surface-modified liposomes with gangliosides prolong their half life in blood stream that associated to the poor immunogenic properties of gangliosides are potentially useful for applications as immunotherapic vehicles. The physical characteristics of these biocolloids play an important role on their stability and exposition of the ganglioside antigens to the immunological system. The present work describes the physical characterization of liposomes incorporating a monosialoganglioside or a mixture of mono-, di- and trisialogangliosides. The liposomal matrix was composed of either dipalmitoylphosphatidylcholine and cholesterol, or in some preparations dihexadecylphosphate, which was added in order to provide a higher negative charge density on the liposome surface. Both types of liposomes were prepared by the dry phospholipids film hydration method and characterized by their phospholipid and ganglioside content, mean diameter, size distribution, morphology, membrane packing, lamellar structure and phase transition behavior. (C) 2004 Elsevier B.V. All rights reserved.25141699175182