Preparation of Loaded Liposomes by Extrusion and Methods of Characterization

Adverse drug effects from chemotherapeutic agents are a well-known deterrent and a potential limiting factor for appropriate treatment regimens of tumors. To circumvent these limitations several approaches for precision chemotherapy have been proposed. Among those, liposomes are the most advanced carriers for drugs to tumor sites. Liposomes are spherical lipid structures that mimic the cell membrane, and their ability to protect and transport biologically active molecule is exploited for the purpose of targeted drug delivery. In this respect, our work describes production and characterization of liposomes via extrusion.

We produced liposomes from mixtures of lipids that included Polyethylene glycol (PEG) to evade the immune system of the host. They were actively loaded with a drug simulator (i.e., Acridine Orange, AO) using a pH gradient. The liposomes were characterized by microscopy and dynamic light scattering for size distribution. The liposomes with the drug simulator were verified by fluorescence spectroscopy and exploitation of self-quenching of AO at high concentration. Our results show that the liposomes produced by extrusion are uniform, PEG addition prevents aggregation, and the pH gradient approach attains large concentration of the loaded molecules.