Liposomes: From the Pioneers to EpigeneticTherapy

LUCIANO BENEDINI; NANCY ANDRÉS; MARIA LAURA FANANI

Liposomes:Historical, Clinical and Molecular Perspectives

Benjamin R. Pearson

Año: 2017; p. 1 - 35

The nanoscience is the discipline that explains the behavior of systems at nanoscopic scale. The liposomes were one of the first nanostructures developed which were rapidly applied in different areas. These systems are structures formed by self-closing phospholipid bilayers in aqueous solutions. The strategies used for their development have leaded them to reach a place of preponderance in drug delivery systems design.For analyzing the properties of liposomes, physicochemical concepts such as those used to describe liquid crystals, must be used. Owing to their amphiphilic nature, the phospholipids form aggregates giving an auspicious framework for the interaction with hydrophilic and lipophilic substances. These properties encouraged the emergence of innumerable modifications and thus, different types of liposomes have already been reported since seventies to present. The main strategies have been focused on increasing their time of permanence in blood circulation and on decreasing their removal by the cells of the mononuclear phagocyte system (MPS) in liver and spleen. For reaching this aim their size was reduced and their membrane fluidity was modified using cholesterol and sphingomyelins. However, one of the most successful strategies was the development of PEGylated liposomes which have been named ?stealth liposomes.?Therefore, this book chapter is addressed to a comprehensive revision of thebibliography regarding to the emergence of liposomes and the first steps in their design, the type of systems (components and structures), their classification and properties.Their experimental physicochemical stability and also theoretical, using DLVOtheory, was analyzed. Furthermore, this text reviews some of the desired properties of liposomes: the loading and the release of drugs, and their relationship with cells which can be mediated or not by receptors among other properties. The lipids, sterols, drugs or other different types of molecules which are able to interact with the liposome membranes can be studied by biophysics techniques because they modify the self-organization at the air-water interface and the states of these systems. Therefore, this point is discussed in a separate section of this chapter.Finally, some approaches about the use of liposomes in the biomedicine field andapproved commercial formulations are revised. Additionally, some proposed perspectives based on their capability to carry molecules, such as silencing RNA (siRNA), which is a strategy used in pharmacoepigenetics therapy, are shown.