The formation of liposomes

Shining light, neutrons and x-rays, on an industrially relevant process in pharmacology and cosmetics

Phospholipid (PL) liposomes are of central importance for industrial formulations. Typically they are obtained by injecting a concentrated ethanolic PL solution (or other alcohol) into water and subsequent application of shear to reduce the liposome size and make them colloidally stable. However, despite the importance of this process, still little is known about the mesoscopic structural changes taking place during liposome formation and the role played by the alcohol. This is even worse for industrial formulations, which normally in addition contain active agents.

The aim of this project is to change this situation. This will be done by studying first the phase behaviour and the mesoscopic structure (light and neutron scattering) of pure PLs together with different alcohols before and after the injection, and then after the subsequent shear treatment. In order to gain insight into the kinetics of the injection process, stopped-flow turbidity, SANS, and SAXS/WAXS experiments will be done.

The study will then be extended to mixed PL systems, as used in industry, active agents will be added and the bending rigidity of the PL bilayers will be determined by NSE. From this comprehensive investigation a thorough understanding of PL liposome formation will be derived, as it is needed to develop more stable and functional liposome formulations ____________________________________________________________________________