Analysis of Subvisible Particles by Light Obscuration (LO) / Single Particle Optical Sensing (SPOS) (CAT#: STEM-MB-2256-CJ)

Introduction

The quantification and characterization of subvisible particles are important for ensuring the quality and safety of therapeutic protein injections. The subvisible particles may consist of rubber from stoppers, glass from containers, filter materials, silicone oil droplets from syringes, and aggregated protein particles. To date, the importance of measuring subvisible particles in therapeutic protein injections has increased as the protein aggregates could elicit not only a decrease of the therapeutic efficacy but also adverse immunogenic reactions. Protein molecules are likely to be adsorbed onto multiple interfaces, such as air-liquid, vial-liquid, and liquid-liquid in vials or syringes. The adsorption of protein molecules to these interfaces results in a conformational change, leading to denaturation, and finally to aggregation. Moreover, therapeutic proteins undergo numerous stresses, such as ultraviolet-light, agitation, and heat during the processes of production, storage, and shipment. These stresses could also generate subvisible particles in therapeutic protein injections.