Effect of Ions on Agitation- and Temperature-Induced Aggregation Reactions of Antibodies

• Published in: Pharmaceutical research Vol. 26; no. 4; pp. 903 - 913
• Main Authors: Fesinmeyer, R. Matthew, Hogan, Sabine, Saluja, Atul, Brych, Stephen R, Kras, Eva, Narhi, Linda O, Brems, David N, Gokarn, Yatin R
• Format: Journal Article
• Language: English
• Published: Boston Boston : Springer US 01-04-2009; Springer US; Springer; Springer Nature B.V
• Subjects: aggregation; Antibodies, Monoclonal - chemistry; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedicine; Chemical bonds; Drug Storage; Excipients - chemistry; General pharmacology; Hofmeister effect; Hot Temperature; Immunoglobulin G - chemistry; Ions; Medical Law; Medical sciences; Models, Chemical; monoclonal antibody; Osmolar Concentration; Pharmaceutical technology. Pharmaceutical industry; Pharmacology; Pharmacology. Drug treatments; Pharmacology/Toxicology; Pharmacy; Protein Conformation; Protein Denaturation; Protein Folding; Protein Stability; Proteins; reduced valence; Research Paper; Solubility; Technology, Pharmaceutical - methods; Temperature; Time Factors; Transition Temperature; Water - chemistry; aggregation; ions; monoclonal antibody; reduced valence; Hofmeister effect; Aggregation; Agitation; Temperature; Pharmaceutical technology; Ions; Monoclonal antibody
• ISSN: 0724-8741; 1573-904X
• DOI: 10.1007/s11095-008-9792-z

Purpose The impact of ions on protein aggregation remains poorly understood. We explored the role of ionic strength and ion identity on the temperature- and agitation-induced aggregation of antibodies. Methods Stability studies were used to determine the influence of monovalent Hofmeister anions and cations on aggregation propensity of three IgG₂ mAbs. The CH2 domain melting temperature (T m₁) and reduced valence (z*) of the mAbs were measured. Results Agitation led to increased solution turbidity, consistent with the formation of insoluble aggregates, while soluble aggregates were formed during high temperature storage. The degree of aggregation increased with anion size (F⁻ < Cl⁻ < Br⁻ < I⁻ < SCN⁻ ~ ClO₄ ⁻) and correlated with a decrease in T m₁ and z*. The aggregation propensity induced by the anions increased with the chaotropic nature of anion. The cation identity (Li⁺, Na⁺, K⁺, Rb⁺, or Cs⁺) had no effect on T m₁, z* or aggregation upon agitation. Conclusions The results indicate that anion binding mediates aggregation by lowering mAb conformational stability and reduced valence. Our observations support an agitation-induced particulation model in which anions enhance the partitioning and unfolding of mAbs at the air/water interface. Aggregation predominantly occurs at this interface; refreshing of the surface during agitation releases the insoluble aggregates into bulk solution.