Electrostatic Interactions Guide the Detrimental Effect of Oleic Acid on Monoclonal Antibody Stability

PURPOSE OR OBJECTIVE: To investigate how polysorbate 80 (PS-80) hydrolysis byproducts, especially oleic acid, affect monoclonal antibody (mAb) stability and contribute to protein particle formation.

The study evaluated oleic acid-associated protein particle formation using microflow imaging (MFI), Scanning Electron Microscopy-Energy Dispersive X-ray spectroscopy (SEM-EDX), field-flow fractionation (FFF), and Fourier Transform Infrared (FT-IR) particle characterization. The proposed electrostatic interaction mechanism was examined by varying ionic strength with saline and arginine, adjusting pH, and considering mAb isoelectric points.

Oleic acid was associated with the formation of proteinaceous particles. The data supported the idea that oleic acid induces mAb aggregation through electrostatic interactions. Oleic acid-induced protein aggregate formation was reversible in the presence of additional salt, suggesting that increased ionic strength disrupts the charged interactions driving aggregation.

PS-80 degradation byproducts, particularly oleic acid, can promote reversible mAb aggregation and particle formation through electrostatic interactions. These findings improve understanding of particle formation in protein formulations and may help guide buffer selection, ionic strength, pH optimization, and prediction of stability in intravenous solutions such as saline.