Extensive Characterization of Polysorbate 80 Oxidative Degradation Under Stainless Steel Conditions

Polysorbate-80 (PS-80) is a common surfactant used in biologics formulations. However, the tendency of oxidation to PS-80 when exposed to stainless steel surfaces brings various challenges during manufacturing processes, such as inconsistent shelf-life of PS-80 solutions, which can further impact the biologics and vaccines production. In this work, the root causes of PS-80 oxidation when in contact with stainless steel conditions were thoroughly investigated through the use of various complementary analytical techniques including U/HPLC-CAD, LC-MS, ICP-MS, peroxide assay, and EPR spectroscopy. The analytical tool kit used in this work successfully revealed a PS-80 degradation mechanism from the perspective of PS-80 content, PS-80 profile, iron content, peroxide production, and radical species. The combined datasets reveal that PS-80 oxidative degradation occurs in the presence of histidine and iron in addition to being combined with the hydroperoxides in PS-80 material. The oxidative pathway and potential degradants were identified by LC-MS. The PS-80 profile based on the U/HPLC-CAD assay provided an effective way to identify early-signs of PS-80 degradation. The results from a peroxide assay observed increased hydroperoxide along with PS-80 degradation. EPR spectra confirmed the presence of histidine-related radicals during PS-80 oxidation identifying how histidine is involved in the oxidation. All assays and findings introduced in this work will provide insight into how PS-80 oxidative degradation can be avoided, controlled, or detected. It will also provide valuable evaluations on techniques that can be used to identify PS-80 degradation related events that occur during the manufacturing process.