1. Introduction................................................................................................	1929
2. Challenges and limitations for the delivery of protein drugs.................	1930
3. Nanocarriers...............................................................................................	1931
3.1. Liposomes...........................................................................................	1933
3.2. Virosomes...........................................................................................	1936
3.3. Solid Lipid Nanoparticles..................................................................	1937
3.4. Polymeric Nanoparticles...................................................................	1940
3.5. Protein Conjugates.............................................................................	1948
4. Targeting strategies and applications.......................................................	1950
4.1. Topical Application............................................................................	1950
4.2. Enhanced Permeability and Retention Effect..................................	1951
4.3. Physical Targeting..............................................................................	1953
4.4. Molecular Targeting...........................................................................	1956
5. Concluding remarks..................................................................................	1961
Acknowledgements.......................................................................................	1962
References.....................................................................................................	1962