Techniques to Improve the Characterization of Protein Particles in Biologic Drug Products

Abstract

The characterization of particulate matter, especially protein aggregates, in the sub-visible and visible size range has become an area of focus in the biopharmaceutical industry. This heightened focus is due, in part, to increasing concern around particles causing immunogenicity, and increased queries from regulatory bodies. There has been extensive research in this area, with many recent publications on related methodologies, mechanisms and influencing factors. Two areas of interest are the characterization of these particles using material sparing approaches and the effect of the presence of silicone oil particles on protein solutions. With the focus on high concentration drug products (¡Ý50 mg/mL), and the drive toward conserving drug product by producing fewer batches, there is a real need for characterization techniques that require less sample. In addition, there is significant interest by the regulatory agencies in obtaining information on particulate matter in biologic drug products over a broad range of sizes. Queries are being generated by the FDA and other regulatory bodies, asking for particle count and any additional compositional information. They are requiring the pharmaceutical industry to have a deeper understanding of the formation of protein particles as well as methods for monitoring a broad range of sizes, over the shelf life of the product. The propensity exists for increased protein aggregation at higher concentrations, yet companies are generating less sample material for testing during development. The focus of this dissertation was to develop approaches for characterizing protein aggregation (particulates) using minimal sample amounts. To develop validatable methods for ongoing drug product monitoring as well as more novel approaches to better understand the nature of particulate matter present in biologic drug products. Silicone oil is present in many drug product contact surfaces and was chosen for further study on the effect of protein aggregation. The methods developed during this research were utilized to characterize protein and/or silicone oil particles, and to provide differentiation between protein and non-protein particles.