Glycan analysis of glycoprotein pharmaceuticals: Evaluation of analytical approaches to Z number determination in pharmaceutical erythropoietin products.

N-Glycosylation of many glycoprotein drugs is important for biological activity and should therefore be the target of specific and quantitative analytical methods. In this study, we focus on the two N-glycan mapping approaches that are used in pharmacopoeial monograph to analyse N-glycans released from fifteen preparations of recombinant human erythropoietin supplied by ten Chinese manufacturers. Underivatised N-glycans were analysed by high performance anion-exchange chromatography with pulsed amperometric detection and fluorophore-labelled N-glycans were analysed by weak anion-exchange and normal-phase high performance liquid chromatography.