After the sample is hydrated to form liposomes, it is generally subjected to preliminary homogenization treatment by high-pressure homogenization or ultrasound. After treatment, the particle size and distribution of the sample will be improved, but often cannot meet the desired ideal requirements. At this point, the homogenized sample is fed into the extruder through the inlet shown in the figure below, and the sample is extruded from the filter membrane using high-pressure nitrogen gas. The particle size and distribution of the extruded sample will further increase.

The membrane material of the pneumatic liposome extruder is polycarbonate (PC), and its pore size uniformity, chemical stability, and surface properties directly affect the quality of liposomes

Aperture control:

The fixed pore size of PC filter membrane (such as 50nm, 100nm, etc.) determines the final particle size of liposomes. Large particle size liposomes are ruptured and recombined through shear force, achieving nanoscale homogenization.

Material properties:

Uniformity: The track etching process ensures a concentrated pore size distribution (± 10% fluctuation), avoiding particle size dispersion caused by uneven pore size in liposomes.

Chemical stability: Resistant to pH 1-14 and organic solvents, preventing contamination of liposomes by filter membrane leaching substances.

Mechanical strength: Tensile strength 15-25MPa, ensuring structural integrity during high-pressure extrusion.

Quality impact:

Particle size distribution: High quality PC filter membrane can reduce the polydispersity index (PDI) of liposomes to 0.01-0.03.

Drug encapsulation efficiency: Mild shear force reduces drug leakage, especially for sensitive drugs such as doxorubicin.