Preparation of liposomes for drug delivery applications by extrusion of giant unilamellar vesicles

Abstract

The potential of liposomes as carriers in drug delivery had been predicted several decades ago and has already seen some success. One of the limitations in liposome preparation for drug delivery applications has been the need to subject suspensions of multilamellar vesicles of several membrane extrusions at high pressures so that liposomes of desired size may be obtained. In this work we have demonstrated that a single-pass extrusion of electroformed giant unilamellar vesicles at moderate pressures yields a monodisperse population of liposomes of the desired size. We also show that low-pass filtration of giant vesicle suspensions to remove smaller vesicles prior to extrusion facilitates better prediction of extruded liposome size. Our results provide new insights into the possible mechanisms involved in size reduction of giant vesicles by extrusion.