Miniaturized Forced Degradation of Therapeutic Proteins and ADCs by Agitation-Induced Aggregation Using Orbital Shaking of Microplates

Microplate-based formulation screening is a powerful approach to identify stabilizing excipients for therapeutic proteins while reducing material requirements. However, this approach is sometimes not representative of studies conducted in relevant container closures. The present study aimed to identify critical parameters for a microplate-based orbital shaking method to screen biotherapeutic formulations by agitation-induced aggregation. For this purpose, an in-depth methodological study was conducted using different shakers, microplates, and plate seals. Aggregation was monitored by size exclusion chromatography, turbidity, and backgrounded membrane imaging. Both shaker quality and liquid-seal contact had substantial impacts on aggregation during shaking and resulted in non-uniform sample treatment when parameters were not suitably selected. The well volume to fill volume ratio (Vwell/Vfill) was identified as an useful parameter for achieving comparable aggregation levels between different microplate formats. An optimized method (2400 rpm [ac 95 m/s2], Vfill 60-100 µL [Vwell/Vfill 6-3.6], 24 h, RT, heat-sealed) allowed for uniform sample treatment independent of surface tension and good agreement with vial shaking results. This study provides valuable guidance for miniaturization of shaking stress studies in biopharmaceutical drug development, facilitating method transfer and comparability between laboratories.