Abstract:
:Reducing viscosities of concentrated solutions of therapeutic proteins is important for their subcutaneous and intravenous delivery. Although inorganic salts and optimizing the pH were previously reported to dramatically lower the viscosity of a monoclonal antibody solution, herein we have determined these effects not to be general. Separately, we have found that hydrophobic ionic excipients, both anionic and cationic, substantially decrease the viscosity of concentrated (300-400 mg/mL) aqueous solutions of bovine serum albumin and γ-globulin. The more hydrophobic the excipient, the greater its viscosity-lowering effect is. With cationic ones, the concomitant contribution of the counter-ion broadly follows the chaotropic order. The most potent excipients lower the viscosity over fourfold to levels far below the 50 cP threshold for subcutaneous injections. The observed viscosity reductions are rationalized in terms of three-dimensional transient protein networks formed in concentrated solutions due to hydrophobic and, to a lesser extent, ionic interactions. These reversible protein aggregates are responsible for strong resistance to flow in concentrated protein solutions and hence their high viscosity; hydrophobic ions apparently effectively compete for these interprotein interactions, thereby giving rise to less viscous solutions.
journal_name
Biotechnol Bioengjournal_title
Biotechnology and bioengineeringauthors
Du W,Klibanov AMdoi
10.1002/bit.22983subject
Has Abstractpub_date
2011-03-01 00:00:00pages
632-6issue
3eissn
0006-3592issn
1097-0290journal_volume
108pub_type
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