Multilamellar vesicles (MLVs) are relatively unstable, and they are not effective drug carriers due to their small core volume. This can be addressed by performing extrusion, whereby the MLVs are forced through polycarbonate filters with defined pore sizes. This disrupts the lipid bilayers of the vesicles, and if the force is strong enough, the MLV is completely torn apart, creating smaller fragments. These fragments immediately form as small unilamellar vesicles (SUVs) or large unilamellar vesicles (LUVs) at the other side of the membrane, with a diameter reflecting the pore size. The resulting unilamellar vesicles are more stable and retain high encapsulation capacity.

Additional passes through the membrane may further reduce the particle size and narrow the particle size distribution, as shown in Figure 2 (below).
 

	Liposome Membrane with 100nm Pore Size
	Schematic representation of the extrusion process.
	Graph reflecting uniformity of size via repeated passages of the liposomes through the membrane.

LUVs may be the desired product of extrusion, as they have high encapsulation efficiency due to their large core volume. Producing these, rather than SUVs, can be achieved simply by increasing the filter pore sizes in the extruder membranes.

Hand Liposome Extruder  Lab 0.5mL-2mL	Jacketed Liposome Extruder Lab, Pilot 2mL-3000mL	Online Liposome Extruder Lab, Pilot, Production 2mL-100L
Hand Drive	Compressed Gas	High Pressure Homogenizer or Pump