Evaluation of a new extrusion device for the production of stable oligolamellar liposomes in a liter scale

A procedure for large-scale production of extruded oligolamellar liposomes was developed. the extrusion technique described is rapid, simple, and reproducible. Vesicles with a diameter in the range of 200-500 nm are obtained. the liposomal preparations were characterized by their specific turbidity (determined spectrophotometrically) and contamination with large particles (> 1 μm). Liposome physical stability was determined using a parameter (P) that relates the ratio of the specific turbidity before and after standardized centrifugation. The extruded oligolamellar liposomes obtained were stable, and after 4 weeks storage at 4°C no irreversible aggregation or fusion of the vesicles occurs. The extrusion process ensures sterilization of the final liposomal product, making it acceptable as a pharmaceutical preparation for parenteral use.