A novel UHPLC-HRMS was developed to quantify a PEGylated protein in serum.
Two tryptic peptides were sensitively detected by HRMS with single ion monitoring.
Quantitation of one disulfide-containing peptide allows in vivo stability evaluation.
The assay was successfully applied to a non-clinical study for stability evaluation.
The method is applicable to disulfide rich-protein drugs not suited for SRM detection.