A versatile supercritical assisted process for the one-shot production of liposomes

Liposomes are spherical vesicles made of a double layer of phospholipids and an inner water volume; these biocompatible drug carriers are used for the vehiculation of hydrophilic, amphiphilic or lipophilic compounds. Conventional methods for the production of liposomes are characterized by several drawbacks such as low encapsulation efficiencies, difficult control of particle size distribution, high solvent residue and necessity of expensive post-processing steps. To overcome these limitations, SuperLip (Supercritical assisted Liposome formation) has been developed, consisting in the inversion of the traditional liposome production steps: water droplets are obtained; then, lipidic layer is formed around them. Nanometric and sub-micrometric vesicles were obtained entrapping proteins, antibodies, antibiotics, essential oils, agricultural additives, antioxidants, dyes and hollow gold nanoparticles. The continuity of the process guaranteed reproducible production of liposome suspensions, whose bulk stability was confirmed for at least 6 months. After process parameters optimization, encapsulation efficiencies up to 99% were obtained.