Preparation and characterization of curcumin-loaded liposomes for delivery to the lungs

Curcumin-loaded liposomes comprising dipalmitoylphosphatidylcholine, cholesterol, and dioleoylphosphatidylethanolamine (72:8:20 mole ratio) were prepared by the thin-film hydration method, followed by probe sonication to achieve a mean diameter <200 nm. The properties of aerosols generated using from 4 mL optimized liposome preparation filled into an air-jet nebulizer were determined using a Fast Screening Impactor (FSI) pre-cooled at 2–8°C for at least 90 min at 15 L/min. Curcumin recovered from the impactor and nebulizer was quantified using a validated high-performance liquid chromatography method. Overall, 2.5% w/w curcumin-loaded liposomes was the optimal formulation based on the maximum encapsulation efficiency of approximately 87% and mean hydrodynamic diameter of 97 nm. This chosen curcumin concentration was effectively aerosolized with a fine particle fraction of 53.25%, and a fine particle dose of 53 µg being deposited on the lower stage of the FSI (cutoff diameter 5 µm)