Liposomes for Protein Delivery: Selecting Manufacture and Development Processes

The use of liposomes as protein carriers has been investigated for a number of possible potential applications in pharmaceutical formulations. These are for sustained release to improve adjuvancy for vaccine development, protein absorption enhancement, and drug targeting carriers and as vehicles for administration of hydrophobic compounds. The majority of current liposomal protein formulations are still in various preclinical research stages, with relatively little known or reported human clinical findings to date. There are still pending challenges to creating commercially stable and bioactive protein formulations with lipids. In addition to lipid developmental issues, because the stability of proteins may be affected by many physical or chemical manipulations, the choice of manufacturing designs for liposomal incorporation becomes somewhat more complex. For this reason, solvent-free vesicle procedures should be the primary approach to the preparation of protein-based formulations. In this regard a variety of recently reported methods are discussed. The advantages or disadvantages of these procedures are compared to those of procedures involving solvents. Consideration to large-scale manufacturing and protein recovery issues is also given.