Capillary electrophoresis separation of the desamino degradation products of oxytocin

Oxytocin ( OT ) is an endogenous and therapeutic hormone necessary for maternal health. It is also the subject of fast growing research in the field of behavioral science. This article describes a rapid CE method using UV detection at 214 nm for the determination of the deamidation products of OT . Deamidation is the most common degradation pathway of peptides and proteins and can lead to reduced therapeutic efficiency of biopharmaceuticals. To achieve a separation of the seven structurally similar desamino peptides from OT , 11 mM sulfobutyl ether β‐CD and 10% v/v MeOH were added to a BGE of 50 mM phosphate buffer at pH 6.0. The assay is linear within ≤5–100 μM for all species with a total analysis time of 12 min. The method was then applied to monitor the heat‐stress degradation of OT at 70°C, where all seven desamino species were observed over a 96 h period.