Long- and Short-Range Electrostatic Interactions Affect the Rheology of Highly Concentrated Antibody Solutions

• Published in: Pharmaceutical research Vol. 26; no. 12; pp. 2607 - 2618
• Main Authors: Chari, Ravi, Jerath, Kavita, Badkar, Advait V, Kalonia, Devendra S
• Format: Journal Article
• Language: English
• Published: Boston Boston : Springer US 01.12.2009; Springer US; Springer; Springer Nature B.V
• Subjects: Antibodies - chemistry; Antibodies - metabolism; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedicine; Circular Dichroism; Computer based modeling; Computer Simulation; General pharmacology; Hydrogen-Ion Concentration; Medical Law; Medical sciences; Models, Biological; Monoclonal antibodies; Pharmaceutical sciences; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Pharmacology/Toxicology; Pharmacy; Proteins; Proteins - metabolism; Research Paper; Rheology; Solutions - chemistry; Static Electricity; Viscosity; computer modeling; viscosity; dipole; highly concentrated protein solutions; protein-protein interactions; Viscosity; Pharmaceutical technology; Antibody; Rheology; Electrostatic interaction; Modeling; Protein; Solution
• ISSN: 0724-8741; 1573-904X
• DOI: 10.1007/s11095-009-9975-2

Purpose To explain the differences in protein-protein interactions (PPI) of concentrated versus dilute formulations of a model antibody. Methods High frequency rheological measurements from pH 3.0 to 12.0 quantitated viscoelasticity and PPI at high concentrations. Dynamic light scattering (DLS) characterized PPI in dilute solutions. Results For concentrated solutions at low ionic strength, the storage modulus, a viscosity component and a measure of PPI, is highest at the isoelectric point (pH 9.0) and lowest at pH 5.4. This profile flattens at higher ionic strength but not completely, indicating PPI consist of long-range electrostatics and other short-range attractions. At low concentrations, PPI are near zero at pI but become repulsive as the pH is shifted. Higher salt concentrations completely flatten this profile to zero, indicating that these PPI are mainly electrostatic. Conclusions This discrepancy occurs because long-range interactions are significant at low concentrations, whereas both long- and short-range interactions are significant at higher concentrations. Computer modeling was used to calculate antibody properties responsible for long- and short-range interactions, i.e. net charge and dipole moment. Charge-charge interactions are repulsive while dipole-dipole interactions are attractive. Their net effect correlated with the storage modulus profile. However, only charge-charge repulsions correlated with PPI determined by DLS.