Several cyclodextrins have been claimed by dozens of papers including huge works of Serno  and Hartl  to be suitable excipients in the formulation of not only small molecules but also certain peptides, proteins and monoclonal antibodies. But why use CDs in protein and biological formulations?
- They are safer than most current excipients (e.g. Tween) – no peroxide formation, corresponding immunogenicity, degradation
- Prevention of aggregation, delay folding
- Less protein adsorption onto container surface
- Reduce/maintain viscosity
- Improve injectability
- Physical and chemical stabilization of proteins
- Life-cycle management
These interesting findings of course generated (and keep generating) a lot of interest and even patents from companies like Genentech or Roche, yet still, there are no products on the market – not even in clinics as far as I know – to date.
What got me thinking about this again is a not so recent patent from Genentech on using cyclodextrins to reduce the degradation rate of polysorbates. If CDs are so nice and effective for this purpose, how come they are not flooding the market?
 T. Serno, E. Hartl, A. Besheer, R. Miller, G. Winter The role of polysorbate 80 and HPbetaCD at the air–water interface of IgG solutions. Pharm. Res., 30 (2013), pp. 117-130
 Y.E. Kim, M.S. Hipp, A. Bracher, M. Hayer-Hartl, F.U. Hartl Molecular chaperons in protein folding and proteostasis. Ann. Rev. Biochem., 82 (2013) 323-355