posted on 2024-02-22, 13:08authored byEstephanie
L. N. Escobar, Valerie P. Griffin, Prajnaparamita Dhar
Interface-induced aggregation resulting in protein particle
formation
is an issue during the manufacturing and storage of protein-based
therapeutics. High-concentration formulations of therapeutic proteins
are even more prone to protein particle formation due to increased
protein–protein interactions. However, the dependence of interface-induced
protein particle formation on bulk protein concentration is not understood.
Furthermore, the formation of protein particles is often mitigated
by the addition of polysorbate-based surfactants. However, the details
of surfactant-protein interactions that prevent protein particle formation
at high concentrations remain unclear. In this work, a tensiometer
technique was used to evaluate the surface pressure of an industrially
relevant mAb at different bulk concentrations, and in the absence
and presence of a polysorbate-based surfactant, polysorbate 20 (PS20).
The adsorption kinetics was correlated with subvisible protein particle
formation at the air–water interface and in the bulk protein
solution using a microflow imaging technique. Our results showed that,
in the absence of any surfactant, the number of subvisible particles
in the bulk protein solutions increased linearly with mAb concentration,
while the number of protein particles measured at the interface showed
a logarithmic dependence on bulk protein concentration. In the presence
of surfactants above the critical micelle concentration (CMC), our
results for low-concentration mAb solutions (10 mg/mL) showed an interface
that is surfactant-dominated, and particle characterization results
showed that the addition of the surfactant led to reduced particle
formation. In contrast, for the highest concentration (170 mg/mL),
coadsorption of proteins and surfactants was observed at the air–water
interface, even for surfactant formulations above CMC and the surfactant
did not mitigate subvisible particle formation. Our results taken
together provide evidence that the ratio between the surfactant and
mAb molecules is an important consideration when formulating high-concentration
mAb therapeutics to prevent unwanted aggregation