The Lipid Extruder is intended for use with MaxSuppressor™ RNA-LANCEr II (Bioo Scientific cat. # 3410-01) for the purpose of homogenizing lipid particles to 100 nm prior to the in vivo administration of the RNAi agent. Upon testing with MaxSuppressor™ In vivo RNA LANCEr II, we have found that extrusion to 100 nm particle size generates a homogeneous size range of particles and increases the delivery efficiency of the agent. Lipid extrusion is a technique in which a lipid suspension is forced through a polycarbonate filter with a defined pore size to yield particles having a diameter near the pore size of the filter used. Extrusion through filters with 100 nm pores typically yields large, unilamellar vesicles with a mean diameter of 120-140 nm. Mean particle size also depends on the lipid composition and is quite reproducible from batch to batch. The extrusion should be done at a temperature above the Tc of the lipid. Attempts to extrude below the Tc will be unsuccessful as the membrane has a tendency to clog with rigid lipid particles that cannot pass through the pores. The Lipid Extruder allows researchers to prepare unilamellar vesicles by extrusion in an efficient, rapid manner. The transition temperature (Tm) of MaxSuppressor™ RNA LANCEr II is below room temperature and thus, no heating or temperature regulation of the device is required. The filter housing is constructed of stainless steel and Teflon allowing for rapid cleaning and autoclaving of all parts.