Extensive Chemical Modifications in the Primary Protein Structure of IgG1 Subvisible Particles Are Necessary for Breaking Immune Tolerance.

A current concern with the use of therapeutic proteins is the likely presence of aggregates and submicrometer, subvisible, and visible particles. It has been proposed that aggregates and particles may lead to unwanted increases in the immune response with a possible impact on safety or efficacy. The aim of this study was thus to evaluate the ability of subvisible particles of a therapeutic antibody to break immune tolerance in an IgG1 transgenic mouse model and to understand the particle attributes that might play a role in this process.

Factors Governing the Accuracy of Subvisible Particle Counting Methods.

A number of new techniques for subvisible particle characterization in biotechnological products have emerged in the last decade. Although the pharmaceutical community is actively using them, the current knowledge about the analytical performance of some of these tools is still inadequate to support their routine use in the development of biopharmaceuticals (especially in the case of submicron methods). With the aim of increasing this knowledge and our understanding of the most prominent techniques for subvisible particle characterization, this study reports the results of a systematic evaluation of their accuracy.

Factors Governing the Precision of Subvisible Particle Measurement Methods - A Case Study with a Low-Concentration Therapeutic Protein Product in a Prefilled Syringe.

Purpose: The current study was performed to assess the precision of the principal subvisible particle measurement methods available today. Special attention was given to identifying the sources of error and the factors governing analytical performance.

Methods: The performance of individual techniques was evaluated using a commercial biologic drug product in a prefilled syringe container.

Measuring Subvisible Particles in Protein Formulations Using a Modified Light Obscuration Sensor with Improved Detection Capabilities.

Although light obscuration is the "gold standard" for subvisible particle measurements in biopharmaceutical products, the current technology has limitations with respect to the detection of translucent proteinaceous particles and particles of sizes smaller and around 2 μm. Here, we describe the evaluation of a modified light obscuration sensor utilizing a novel measuring mode. Whereas standard light obscuration methodology monitors the height (amplitude) of the signal, the new approach monitors its length (width).