Experimental Model System to Study pH Shift-Induced Aggregation of Monoclonal Antibodies Under Controlled Conditions

Abstract

Purpose: To present a convenient screening method for evaluating additive effects on the renaturation of an acid-exposed monoclonal antibody (mAb).

Methods: The assay involves brief incubation of a mAb at acidic pH and subsequent neutralization in the absence or presence of additive to induce mainly aggregation. An increase in absorbance depicted aggregation. The recorded aggregation data traces were fitted with a nucleation-autocatalytic growth model for the extraction of kinetic parameters.

Results: All kinetic data traces were fitted successfully with the selected model and the adjusted R square values were greater than 0.99. Trehalose had strongly stabilizing, proline mildly stabilizing and trimethylamine oxide had destabilizing effects on both the nucleation and growth phase of the reaction. Histidine was strongly stabilizing but was limited by its poor solubility.

Conclusion: The results demonstrate the suitability of the experimental mAb aggregation system and the nucleation-autocatalytic growth fit in the screening and quantification of additive effects on the renaturation of an acid-exposed mAb respectively. This will aid the investigation and derivation of quantitative structure-activity relationships of additive effects on mAb solubility.

Keywords: aggregation kinetics; autocatalytic growth; monoclonal antibody; nucleation; refolding.