title: Non-aqueous suspensions of antibodies are much less viscous than equally concentrated aqueous solutions.
abstract: OBJECTIVE
  The aim of this study was to markedly lower the viscosities of highly concentrated protein, in particular antibody, formulations. An effective approach elaborated herein for γ-globulin and a monoclonal antibody is to replace aqueous solutions with equimolar suspensions in neat organic solvents.
  
  
  METHODS
  Viscosities of aqueous solutions and non-aqueous suspensions of the model protein bovine γ-globulin and a murine monoclonal antibody were examined under a variety of experimental conditions. In addition, protein particle sizes were measured using dynamic light scattering and light microscopy.
  
  
  RESULTS
  Concentrated suspensions of amorphous γ-globulin powders (up to 300 mg/mL, composed of multi-micron-sized particles) in absolute ethanol and a number of other organic solvents were found to have viscosities up to 38 times lower than the corresponding aqueous solutions. Monoclonal antibody follows the same general trend. Additionally, the higher the protein concentration and lower the temperature, the greater the viscosity benefit of a suspension over a solution.
  
  
  CONCLUSIONS
  The viscosities of concentrated γ-globulin and monoclonal antibody suspensions in organic solvents are drastically reduced compared to the corresponding aqueous solutions; the magnitude of this reduction depends on the solvent, particularly its hydrogen-bonding properties.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Building 56-579, Cambridge, Massachusetts 02139, USA.
authors.forename: Charudharshini
authors.initials: C
authors.lastname: Srinivasan
authors.forename: Alisha K
authors.initials: AK
authors.lastname: Weight
authors.forename: Till
authors.initials: T
authors.lastname: Bussemer
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Klibanov
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D002417:Cattle; D000431:Ethanol / Q000737:chemistry; D051379:Mice; D012492:Salts / Q000737:chemistry; D012996:Solutions; D013501:Surface-Active Agents / Q000737:chemistry; D013535:Suspensions; D014783:Viscosity; D014867:Water / Q000737:chemistry; D005719:gamma-Globulins / Q000737:chemistry*
chemical_list: D000911:Antibodies, Monoclonal; D012492:Salts; D012996:Solutions; D013501:Surface-Active Agents; D013535:Suspensions; D005719:gamma-Globulins; D014867:Water; D000431:Ethanol
references.citation: Methods Enzymol. 1990;182:285-300
references.pmid: 2314242
references.citation: J Protein Chem. 1989 Oct;8(5):661-8
references.pmid: 2610860
references.citation: J Pharm Sci. 2009 Sep;98(9):3043-57
references.pmid: 18823016
references.citation: Nat Rev Drug Discov. 2005 Apr;4(4):298-306
references.pmid: 15803194
references.citation: Nat Rev Immunol. 2010 May;10(5):317-27
references.pmid: 20414205
references.citation: Pharm Res. 2012 Nov;29(11):3102-9
references.pmid: 22692671
references.citation: J Pharm Sci. 2009 Sep;98(9):3108-16
references.pmid: 19025898
references.citation: J Pharm Sci. 2008 Oct;97(10):4219-27
references.pmid: 18240303
references.citation: ACS Nano. 2012 Feb 28;6(2):1357-69
references.pmid: 22260218
references.citation: Nature. 2001 Jan 11;409(6817):241-6
references.pmid: 11196652
references.citation: J Bacteriol. 2004 Aug;186(15):5129-37
references.pmid: 15262949
references.citation: Biotechnol Bioeng. 2011 Mar;108(3):632-6
references.pmid: 21246510
references.citation: Langmuir. 2010 Jan 19;26(2):1067-74
references.pmid: 19803503
references.citation: J Pharm Sci. 2012 Dec;101(12):4433-43
references.pmid: 23001898
references.citation: J Pharm Sci. 2010 Dec;99(12):4812-29
references.pmid: 20821382
references.citation: Nat Rev Immunol. 2010 May;10(5):345-52
references.pmid: 20414207
references.citation: Proc Natl Acad Sci U S A. 2003 Jun 10;100(12):6934-9
references.pmid: 12782786
references.citation: Expert Opin Biol Ther. 2004 Mar;4(3):301-17
references.pmid: 15006725
references.citation: Anal Biochem. 2010 Apr 1;399(1):141-3
references.pmid: 19995543
references.citation: Biophys J. 2007 Jul 15;93(2):610-9
references.pmid: 17449660
references.citation: J Pharm Sci. 2004 Jun;93(6):1390-402
references.pmid: 15124199