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Updated: May 21, 2026

Solubility of Hydrophobic Compounds in Aqueous Solution Using Combinations of Self-assembling Peptide and Amino Acid
Published on: September 20, 2017
Structure-activity relationship for hydrophobic salts as viscosity-lowering excipients for concentrated solutions of
Zheng Guo1, Alvin Chen, Roger A Nassar
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Purpose:
To discover, elucidate the structure-activity relationship (SAR), and explore the mechanism of action of excipients able to drastically lower the viscosities of concentrated aqueous solutions of humanized monoclonal antibodies (MAbs).
Methods:
Salts prepared from hydrophobic cations and anions were dissolved into humanized MAbs solutions. Viscosities of the resulting solutions were measured as a function of the nature and concentration of the salts and MAbs.
Results:
Even at moderate concentrations, some of the salts prepared herein were found to reduce over 10-fold the viscosities of concentrated aqueous solutions of several MAbs at room temperature.
Conclusions:
To be potent viscosity-lowering excipients, the ionic constituents of the salts must be hydrophobic, bulky, and aliphatic. A mechanistic hypothesis explaining the observed salt effects on MAb solutions' viscosities was proposed and verified.
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