Acidic and alkaline hydrolysis of polysorbates under aqueous conditions: Towards understanding polysorbate degradation in biopharmaceutical formulations.

Polysorbate is one of the most commonly employed non-ionic surfactant in protein containing biological formulations, whereby, it can stabilize these biomolecules under different stress conditions. Despite the fact that polysorbates are present in almost 70 % of currently marketed parenteral biological drugs, polysorbate degradation in biopharmaceutical formulations has emerged as a specific quality concern. Different degradation pathways have been explored in the recent years with the aim of understanding the root cause for polysorbate degradation in biopharmaceutical formulations. In an attempt to explore hydrolytic degradation of polysorbates in accelerated degradation conditions, we studied extreme pH conditions. We investigated specific polysorbate degradation profiles depending on acidic or alkaline solution conditions. The acidic and alkaline hydrolysis of polysorbate is monitored for the total content using a fluorescence micelle assay (FMA). Additionally, the compositional changes in polysorbates were detected using reversed phase high performance liquid chromatography coupled to a charged aerosol detector (RP-HPLC-CAD). We show that the stability of polysorbate against chemical hydrolysis is dependent upon selected pH condition and differ for polysorbate 20 and polysorbate 80. Additionally, we were able to show that a degradation pathway dependent fingerprint may support the identification of the degradation root cause.