Identification of peptides in the trypsin peptide map of a commercial drug product

Situation: A client company had indications that their existing manufacturing process was promoting oxidation in a protein commercial drug product.  Improvements in the analytical methodology were necessary to assess the level of oxidation in the current process and to quantify the effect of processing changes.

Task: Evaluate the current methodology and assess its ability to monitor the level of oxidation on samples subjected to oxidative conditions; make necessary method improvements.

Action: The client’s trypsin peptide map methodology of their commercial drug product was improved by switching from traditional HPLC separation of the peptides to UPLC separation.  The UPLC separation significantly improved the chromatographic resolution of oxidized methionine-containing peptides.  The peptides, including oxidized methionine containing peptides, were identified using time-of-flight mass spectrometry.  The combination of UPLC separation with high resolution mass spectrometry resulted in substantial methodology improvements and allowed for appropriate assessment of protein oxidation. The effect of processing changes was evaluated with the improved methodology.

Result: The improved method contributed to the client’s success in transitioning from their old manufacturing process to a new manufacturing process for their commercial drug product