(M1430-02-10) Defining a Scale-Down Agitation Model for Early-Stage High Concentration Biologics Formulation Development

Purpose: A scale-down agitation model is commonly used to simulate mechanical stresses encountered during various stages of drug product lifecycle including formulation development, manufacturing, transportation, storage and administration that may lead to foaming, protein aggregation, or particles formation, thereby impacting product quality. The purpose of this study is to define the agitation stress testing conditions and endpoints by comparing physical stress models in different container closure systems (CCS).

Methods: Three physical agitation models - an orbital shaker, a multichannel vortexer, and a bench-top shipping simulator (VR5500) were systematically evaluated to simulate mechanical stresses relevant to drug product handling and distribution. A preliminary screening study was performed with an agitation-sensitive molecule using Type I 2R, and 6R vials assessed with varying fill volumes to identify representative CCS and optimize agitation parameters for subsequent analysis. Subsequently, the three agitation stress models were compared to determine their suitability for formulation development and their potential applicability as validated testing conditions. The study utilized high-concentration biologics formulations representative of clinical and commercial products. Samples were analyzed for quality attributes (QA) such as high molecular weight species (HMWS) by size-exclusion ultra- performance liquid chromatography (SE-UPLC), subvisible particles (SVP) by micro flow imaging (MFI), and turbidity by optical density (OD). Additionally, the impact of varying fill volumes in 2R vials was systematically investigated using the selected agitation model to inform early-stage formulation development.

Results: The CCS screen study indicated that horizontal placement on the orbital shaker subjected samples to greater stress than vertical placement, while the opposite trend was observed with the vortexer. A fill volume of 4 mL in 6R vials was selected for subsequent agitation model comparisons. When comparing agitation models, both the orbital shaker (200 RPM) and vortexer (1200 RPM) subjected samples to severe mechanical stress than VR5500, enabling robust stress conditions suitable for formulation development studies. The results also indicate that the orbital shaker predominantly promotes the formation of HMWS, while the vortexer is more likely to induce the generation of SVP, demonstrating different agitation models impact distinct QA. Based on these findings, agitation for 24 hours at ambient temperature using the orbital shaker was identified as an appropriate stress condition for formulation development studies. For early-stage formulation development, the 2R vial were selected as the standard configuration for agitation testing due to material constraints. In the final phase, fill volumes ranging from 0.5 mL to 2mL in 2R vials were systematically assessed. The extent of change in QA, such as HMWs or SVP formation, was found to be depended on the fill volume. A minimum fill volume of 1 mL was determined to be optimal for agitation stress testing during early-stage formulation development.

Conclusion: This study defines a scientifically justified agitation model for early stage formulation development of high-concentration biologics. The data supports the use of 2R vials with a minimum fill volume of 1 mL, positioned in horizontal placement, and subjected to orbital shaker agitation at ambient temperatures up to 24 hours. This setup and testing approach offer a reliable and consistent way to assess how mechanical stress affects product quality, helping to identify stable formulations in early development.