Quantification of polysorbate 80 in biopharmaceutical formulations implementing an optimized colorimetric approach

Abstract

<jats:p><jats:bold>Objectives</jats:bold>. We hereby describe an improvement of a previously developed quantification technique for polysorbate 80 in biopharmaceutical formulations (darbepoetin alfa and eculizumab) and report the validation of the new approach.</jats:p><jats:p><jats:bold>Methods</jats:bold>. Polysorbate was isolated from analyte samples by protein precipitation using an organic solvent, followed by supernatant evaporation in vacuum. Polysorbate was derivatized using a ferric thiocyanate reagent and extracted into an organic phase; the relevant optical density measurements were performed.</jats:p><jats:p><jats:bold>Results</jats:bold>. We established the optimal conditions for each step of the analysis procedure. The accuracy was 97–102% in the tested analytical range, the relative standard deviation did not exceed 5%, and the limit of quantification was 0.01 mg/mL.</jats:p><jats:p><jats:bold>Conclusions.</jats:bold> The reported approach is highly sensitive; polysorbate isolation and quantification do not depend on the matrix or, most importantly, the protein.</jats:p>