title: Degradation Mechanisms of Polysorbate 20 Differentiated by18O-labeling and Mass Spectrometry.
abstract: To investigate the mechanisms of polysorbate (PS) degradation with the added objective of differentiating the hydrolysis and oxidation pathways.
  
  
  
  Ultra-performance liquid chromatography mass spectrometry (UPLC-MS) was utilized to characterize all-laurate polysorbate 20 (PS20) and its degradants.18O stable isotope labeling was implemented to produce18O-labeled degradation products of all-laurate PS20 in H218O, with subsequent UPLC-MS analysis for location of the cleavage site on the fatty acid-containing side chain of PS20.
  
  
  
  The analysis reveals that hydrolysis of all-laurate PS20 leads to a breakdown of the ester linkage to liberate free lauric acid, showing a distinct dependence on pH. Using a hydrophilic free radical initiator, 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) to study the oxidative degradation of all-laurate PS20, we demonstrate that free lauric acid and polyoxyethylene (POE) laurate are two major decomposition products. Measurement of18O incorporation into free lauric acid indicated that hydrolysis primarily led to18O incorporation into free lauric acid via "acyl-cleavage" of the fatty acid ester bond. In contrast, AAPH-exposure of all-laurate PS20 produced free lauric acid without18O-incorporation.
  
  
  
  The18O-labeling technique and unique degradant patterns of all-laurate PS20 described here provide a direct approach to differentiate the types of PS degradation.
authors.affiliation: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas, 66047, USA.|Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, 46285, USA.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Late Stage Pharmaceutical Development, Genentech Inc., South San Francisco, California, 94080, USA.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Yadav
authors.affiliation: Late Stage Pharmaceutical Development, Genentech Inc., South San Francisco, California, 94080, USA.
authors.forename: Barthélemy
authors.initials: B
authors.lastname: Demeule
authors.affiliation: Late Stage Pharmaceutical Development, Genentech Inc., South San Francisco, California, 94080, USA.
authors.forename: Y John
authors.initials: YJ
authors.lastname: Wang
authors.affiliation: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas, 66047, USA.
authors.forename: Olivier
authors.initials: O
authors.lastname: Mozziconacci
authors.affiliation: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas, 66047, USA. schoneic@ku.edu.
authors.forename: Christian
authors.initials: C
authors.lastname: Schӧneich
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004952:Esters / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry; D006868:Hydrolysis; D007850:Lauric Acids / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010103:Oxygen Isotopes / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D011136:Polysorbates / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D004952:Esters; D005609:Free Radicals; D007850:Lauric Acids; D010103:Oxygen Isotopes; D011136:Polysorbates; C030358:lauric acid; D011092:Polyethylene Glycols; D010100:Oxygen
keywords: 18O-labeling; free lauric acid; hydrolysis; mass spectrometry; oxidation; polysorbate 20