Nowadays, the freeze-drying of liposome dispersions is still necessary to provide a solid
dosage form intended for different routes of administration (i.e., parenteral, oral, nasal and/or
pulmonary). However, after decades of studies the optimization of process conditions remains
still challenging since the freezing and the dehydration destabilize the vesicle organization with
the concomitant drug leakage. Starting from the thermal properties of phospholipids, this work
reviews the main formulation and process parameters which can guarantee a product with suitable
characteristics and increase the efficiency of the manufacturing process. In particular, an overview of the cryo- and/or lyo-protective mechanisms of several excipients and the possible use of co-solvent mixtures is provided. Attention is also focused on the imaging methods recently proposed to
characterize the appearance of freeze-dried products and liposome dispersions upon reconstitution.
The combination of such data would allow a better knowledge of the factors causing inter-vials
variability in the attempt to improve the quality of the final medicinal product.
Pharmaceutics 2018, 10, 139; doi:10.3390/pharmaceutics10030139 - www.mdpi.com/journal/pharmaceutics