Effect of Freeze-Thawing Study on Curcumin Liposome for Obtaining Better Freeze-Dried Product

Liposomes are widely used in the pharmaceutical, biopharmaceutical, cosmetic, and nutraceutical sectors as an efficacious drug-delivery system for improving the bioavailability and protection of the entrapped drug molecule. The present study evaluates freeze-thaw as a simple approach for screening the most appropriate lyoprotectant. The freeze-thaw study is based on the principle that an excipient, which protects liposomes during the first step of freezing, is likely to be an effective lyoprotectant. Curcumin liposomes with high entrapment efficiency were prepared using a lipid film hydration technique. The freeze-thawing study was carried out using various lyoprotectants such as sucrose, mannitol, lactose, dextrose, and maltose. Sucrose showed minimal particle size change with better cryoprotection after the freeze-thaw study. The internal and external addition of sucrose during formulation has shown significant effects on the retention of particle size and curcumin content during the freeze-thawing and drying studies, respectively. Scanning electron microscopy revealed round vesicles with a size ∼131 nm, which correlated well with zeta sizer particle size measurements. Infrared spectra and X-ray diffraction suggested interaction between the sugar and the liposomes and amorphization of the final freeze-dried product. The good correlation between freeze thawing and freeze drying suggests the freeze-thaw study as a simple and quick approach for screening optimal cryoprotectant for freeze drying.