In vivo metabolic pathways and tissue distribution of pharmaceutical excipient polysorbate 80 using ultra-high performance liquid chromatography-high resolution mass spectrometry analysis

Polysorbate 80 (PS80) is a pharmaceutical excipient widely used in injectables, antibody drugs and vaccines. Due to complex composition, its in vivo analysis is challenging, and there are few studies on its metabolic characteristics and pathways in vivo. In this study, a novel analytical method using ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLCHRMS) was developed to comprehensively characterize the components and metabolites of PS80 in biological samples with “omics analysis” feature. Based on this method, 272 components and metabolites belonging to 11 types were identified in rats after intravenous injection of PS80, with POE sorbitan (44.5 %/43.6 %, female/male), POE isosorbitan (22.6 %/23.1 %, female/male), POE (7.3 %/7.4 %, female/male), POE sorbitan dioleate (13.9 %/14.1 %, female/male), and POE sorbitan trioleate (8.4 %/8.3 %, female/male) having higher plasma exposure according to their AUC_(0-t) proportion. The esterified components were rapidly hydrolyzed stepwise from tetra-esterified, tri-esterified, di-esterified, and mono-esterified to non-esterified metabolites in the circulatory system. The hydrolysis rate was related to their parent nucleus and degree of esterification: POE oleate>POE isosorbitan oleate>POE sorbitan oleate; mono-esterification>tri-esterification>di-esterification. PS80 metabolites were rapidly and widely distributed in various tissues and organs, with particularly high exposure in immune organs, such as spleen, thymus, and lymphaden. It was first found that the spleen had high exposure and slow clearance of the PS80 metabolites POE sorbitan and POE isosorbitan, and was significantly enriched in the esterified metabolites POE sorbitan dioleate and POE sorbitan monooleate. Ultimately, the non-esterified metabolites were excreted in urine primarily, with some via bile and feces. This study elucidated the exposure characteristics and metabolic pathways of PS80 in vivo for the first time, and it was helpful for the development, quality control and clinical safety studies of related formulations.