Comparison of Protein Particle Formation in IgG1 mAbs Formulated with PS20 Vs. PS80 When Subjected to Interfacial Dilatational Stress

Abstract

Polysorbates (PS) are nonionic surfactants that are commonly included in protein formulations to mitigate the formation of interfacial stress-induced protein particles and thus increase their long-term storage stability. Nonetheless, factors that dictate the efficiency of different polysorbates in mitigating protein particle formation, especially during the application of interfacial stresses, are often ill defined. Here, we used a Langmuir trough to determine the surface activity of two IgG1 monoclonal antibodies formulated with two different polysorbates (PS20 and PS80) when subjected to interfacial dilatational stress. Interfacial properties of these formulations were then correlated with characterization of subvisible protein particles measured by micro-flow imaging (MFI). Both mAbs, when formulated in PS20, demonstrate faster adsorption kinetics and higher surface activity compared to PS80 or surfactant-free formulations. Compression/expansion results suggest that when exposed to interfacial dilatational stresses, both mAb/PS20 formulations display interfacial properties of PS20 alone. In contrast, interfacial properties of both mAb/PS80 formulations suggest mAbs and PS80 are co-adsorbed to the air-water interface. Further, MFI analysis of the interface and the bulk solution confirms that PS20 is more effective than PS80 at mitigating the formation of larger particles in the bulk solution in both mAbs. Concomitantly, the efficiency of PS to prevent interface-induced protein particle formation also depended on the protein's inherent tendency to aggregate at a surfactant-free interface. Together, the studies presented here highlight the importance of determining the interfacial properties of mAbs, surfactants, and their combinations to make informed formulation decisions about the choice of surfactant.

Keywords: air–water interface; interface-induced protein particle formation; interfacial dilatational stress; protein aggregation.

Fig. 1

Comparison of SP versus time adsorption curves for of two mAb formulations formulated with either 100 ppm PS20 or 100 ppm PS80. PS20 and PS80 control solutions (left) formulated with mAb1 (middle) or with mAb2 (right) in PBS buffer at pH 7.6. Adsorption curves are presented as average (n = 3)

Fig. 2

Comparison of SP versus time adsorption curves for of two mAb formulations formulated with either 10 ppm PS20 or 10 ppm PS80. PS20 and PS80 control solutions (left) formulated with mAb1 (middle) or with mAb2 (right) in PBS buffer at pH 7.6. Adsorption curves are presented as average (n = 3)

Fig. 3

Comparison of the effect that dilatational interfacial stress has on mAb1 and mAb2 solutions formulated with 100 ppm PS20 and PS80 that were exposed to 750 cycles of interfacial compression and expansion in a Langmuir trough at a rate of 150 mm/min. Cycle 1 (blue), cycle 2 (orange), and cycle 750 (red). The isotherms are presented as representative. Three repeats were done

Fig. 4

Comparison of the effect that dilatational interfacial stress has on mAb1 and mAb2 solutions formulated with 10 ppm PS20 and PS80 that were exposed to 750 cycles of interfacial compression and expansion in a Langmuir trough at a rate of 150 mm/min. Cycle 1 (blue), cycle 2 (orange), and cycle 750 (red). The isotherms are presented as representative. Three repeats were done

Fig. 5

Aspect ratio (AR) versus circularity (C) heat maps depicting particle size (ECD) distribution for the protein mAb1 or mAb2 without any surfactant (control, top row), mAb1, or mAb2 formulated in 100 ppm PS80 (middle row), and mAb1/mAb2 formulated in 100 ppm PS20 (bottom row). mAb1 and mAb2 are at 0.5 mg/mL in PBS buffer at pH 7.6 with 100 ppm of both surfactants. MFI was obtained after a 2-h adsorption and 750 compression cycles at 150 mm/min. Heat maps are representative figures with N = 3. Control**: represents protein samples without surfactants that were previously published in Vaclaw et al. J. Pharm Sci, 110(2) 746–759, 2021

Fig. 6

Aspect ratio (AR) versus circularity (C) heat maps depicting particle size (ECD) distribution for the protein mAb1 or mAb2 without any surfactant (control, top row), mAb1, or mAb2 formulated in 10 ppm PS80 (middle row), mAb1/mAb2 formulated in 10 ppm PS20 (bottom row). mAb1 and mAb2 are at 0.5 mg/mL in PBS buffer at pH 7.6 with 100 ppm of both surfactants. MFI was obtained after a 2-h adsorption and 750 compression cycles at 150 mm/min. Heat maps are representative figures with N = 3. Control**: protein controls without surfactant were previously published in Vaclaw et al. J. Pharm Sci, 110(2) 746–759, 2021

Fig. 7

Concentration of protein particles with size > 10 and > 25 um formed at the interface and in bulk solution per mL of solution for mAbs1 and 2 formulated in 100 and 10 ppm of PS80 and PS20 after being subjected to interfacial dilatational stress for 6 h (N = 3)