title: Identification of Subvisible Particles in Biopharmaceutical Formulations Using Raman Spectroscopy Provides Insight into Polysorbate 20 Degradation Pathway.
abstract: OBJECTIVE
  To study composition and heterogeneity of insoluble subvisible particles in Mab formulations resulting from degradation of polysorbate 20 and to develop a better understanding of the mechanisms of polysorbate degradation leading to particle formation.
  
  
  METHODS
  In this study, we exploit the potential of Raman microscopy for chemical identification of particles in monoclonal antibody formulations. Through a combination of experiments and density functional theory (DFT) calculations, we identified unique spectral marker bands for insoluble degradation products of polysorbate 20. We first applied our methodology to identify particles in model systems containing complex mixtures of fatty acids and then to subvisible particles in antibody formulations stored at 5°C for several years.
  
  
  RESULTS
  Most of the subvisible particles identified were comprised of mixtures of fatty acids with no observable signal from fatty acid esters consistent with hydrolysis being the predominant degradation mechanism leading to particulate formation under these storage conditions.
  
  
  CONCLUSIONS
  Our methodology is generally applicable for identification of particles in antibody formulations and, in particular, has the potential to give detailed information about particle heterogeneity and insight into mechanistic aspects of particle formation.
authors.affiliation: Late Stage Pharmaceutical Development, Genentech Inc., South San Francisco, California, 94080, USA, saggu.miguel@gene.com.
authors.forename: Miguel
authors.initials: M
authors.lastname: Saggu
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Ankit
authors.initials: A
authors.lastname: Patel
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry; D001702:Biopharmaceutics / Q000379:methods; D002626:Chemistry, Pharmaceutical / Q000379:methods; D005227:Fatty Acids / Q000737:chemistry; D006868:Hydrolysis; D010316:Particle Size; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011136:Polysorbates / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods
chemical_list: D000911:Antibodies, Monoclonal; D005227:Fatty Acids; D004364:Pharmaceutical Preparations; D011136:Polysorbates