Fabrication and characterization of nanoparticles with lecithin liposomes and poloxamer micelles: Impact of conformational structures of poloxamers

In this study, we fabricated and characterized nanoparticles with a core/shell structure using lecithin and poloxamer. We also evaluated their ability to load proteins. At a lecithin/poloxamer ratio of 0.2, the sizes of lecithin/P188 (low molecular weight poloxamer) and lecithin/P338 (high molecular weight poloxamer) nanoparticles were 316.1 and 280.7 nm, respectively. Lecithin/P188 nanoparticles easily lost core/shell structure at pH 3 and 7. Lecithin/P338 nanoparticles were stable at pH 7 but unstable at pH 3. Only lecithin/P338 nanoparticles exhibited stability in response to temperature changes, despite an increase in their size with decreasing temperature. Loading a model protein with a high isoelectric point (pI) in liposome/poloxamer nanoparticles seemed impossible. A model protein with low pI was efficiently loaded in lecithin/poloxamer nanoparticles, and the maximum loading capacity of lecithin/P188 and lecithin/P338 nanoparticles was 14.85 and 42.34 mg/g particle, respectively. However, lecithin/P188 nanoparticles loading this model protein lost their core/shell structure.