Transfer of a lipophilic drug (temoporfin) between small unilamellar liposomes and human plasma proteins: influence of membrane composition on vesicle integrity and release characteristics

AbstractThe introduction of PEG lipid conjugates into lipid bilayers leads to long circulating liposomes with improved pharmacokinetics and pharmacodynamics characteristics. The concentration range of PEG-lipids is limited by their micelle forming properties. We investigated two phosphatidyl oligoglycerols as potential alternatives to PEG-lipid conjugates and compared their micelle forming properties after incorporation of increasing amounts of oligoglycerols into gel-phase liposomes via cryo-transmission electron microscopy. The incorporation of highly hydrophobic drugs into liposomes makes water soluble formulations possible and improves the therapeutic properties of the drug. We incorporated the hydrophobic photosensitizer temoporfin into liposomes varying in membrane fluidity and nature of surface modifying agents. The main purpose of this study was the investigation of liposome integrity and temoporfin incorporation stability in the presence of plasma. After incubation of temoporfin-loaded liposomes ...