Novel Strategy to Rapidly Profile and Identify Oxidized Species of Polysorbate 80 Using Ultra-High-Performance Liquid Chromatography Coupled with High-Resolution Mass Spectrometry

Polysorbate 80 (PS80) is widely used as an excipient in vaccines and biopharmaceuticals. The oxidized species of PS80 have raised concern because of their potential to compromise product stability and pose a clinical risk. Analytical methods to profile and identify the oxidized species are hard to develop owing to their complexity and low abundance. Herein, a novel strategy was demonstrated to comprehensively profile and identify the oxidized species of PS80 using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. The characteristic fragmentation patterns of the oxidized species were obtained under the "all ions" scan mode. Then, 10 types of distinct fragments from oxidized oleates were identified and confirmed using two purified oxidized species (polyoxyethylene (POE) sorbitan mono-hydroxy oleate and POE mono-keto oleate) whose structures were elucidated via nuclear magnetic resonance. A total of 348 (32 types) oxidized species were profiled and identified in the oxidized PS80 samples, including 119 (10 types) species found for the first time to our knowledge. Mathematical models were established and validated based on the good logarithmic relation between the POE degree of polymerization and the relative retention time and used to rapidly discover and identify the oxidized species. A novel strategy was established to profile and identify the PS80 oxidized species based on their retention time, HRMS, and HRMS² data of the detected peaks using an in-house dataset. Using this strategy, 104 (14 types) and 97 (13 types) oxidized species were identified for the first time in PS80 and its preparations, respectively.