Thermodynamic, viscoelastic and electrical properties of lipid membranes in the presence of astaxanthin

Among numerous compounds found in marine organisms, astaxathin has received considerable research interest due to beneficial impact on health such as anti-inflammatory, antioxidant and neuroprotective activity. Recently new functionalities of this xanthophyll have been revealed indicating important applications in nutrition and pharmacy. However, astaxanthin, as the bioactive, has limited value without a protecting carrier that provides controlled release in a human body. Fabrication of liposomes as efficient drug delivery systems is promising strategy that may overcome these problems. However, the development of new delivery systems requires comprehensive understanding of physicochemical properties of carotenoids and their carriers as well as the interactions between them. The aim of this study was to investigate the mixed lipid-sterol monolayer in the presence of astaxanthin in terms of thermodynamic, morphological and viscoelastic behaviour. The results have been discussed in relation to pure lipid-sterol films. In addition we determined the surface charge density of the liposomes built of these components. The results are helpful in better understanding the role of interfacial viscoelasticity in the quality of liposomal drug delivery forms.