Ultra-performance liquid chromatography/multiple reaction monitoring mass spectrometry quantification of trastuzumab in human serum by selective monitoring of a specific peptide marker from the antibody complementarity-determining regions

RATIONALE: Because of the large molecular weight, the structural complexity and the similarity with endogenous immunoglobulins present in high concentrations, in vivo quantitative studies with therapeutic monoclonal antibodies are particularly challenging. In this work, an UPLC/MRM MS-based methodology is described for the quantification of trastuzumab in human serum by monitoring a novel specific peptide marker located within its heavy chain Complementarity-Determining Region (CDR).