Peptide Mapping of Antibody Drugs by Nexera-i

Importance of the Topic

Peptide mapping by HPLC is critical in ensuring the primary structure integrity of antibody therapeutics. It allows confirmation of amino acid sequences, detection of mutations, and assessment of product consistency during development and quality control.

Objectives and Study Overview

This study demonstrates the application of the Nexera-i integrated UHPLC system combined with a core-shell C18 column for high-resolution peptide mapping of human IgG tryptic digest. The goals include achieving clear separation of digestion peptides and evaluating system repeatability for reliable structural confirmation.

Methodology

• Sample Preparation: Reduction of disulfide bonds with dithiothreitol, alkylation with iodoacetamide, and digestion with trypsin at 37°C for 20 h.
• Chromatographic Conditions: Reversed-phase separation using an Aeris 1.7 µm PEPTIDE XB-C18 column (150 mm × 2.0 mm, 100 Å).
• Gradient Program: Mobile phase A (0.1% TFA in water) to B (0.08% TFA in acetonitrile) from 0% to 45% over 90 min, then to 100% B and re-equilibration.
• Flow Rate and Temperature: 0.2 mL/min at 60 °C.

Instrumentation Used

• Nexera-i integrated UHPLC system with optimized low-pressure gradient valve and 300 µL mixer for TFA gradients.
• Detector: LC-2040C 3D UV detector at 215 nm with high-speed high-sensitivity flow cell.

Key Results and Discussion

The method yielded a chromatogram with an extensive number of well-resolved peptide peaks, facilitating detailed mapping. Intra-day repeatability tests (n=6) showed %RSD values below 0.3% for six representative peaks (retention times 9.93–74.54 min). Inter-day repeatability over six days (n=6) maintained %RSD below 0.16%. These results demonstrate exceptional precision in retention time stability, critical for consistent peptide identification.

Benefits and Practical Applications

• High resolution enables robust confirmation of antibody primary structure and detection of sequence variants.
• Excellent repeatability supports routine QC and method transfer across laboratories.
• Core-shell column and integrated UHPLC system reduce analysis time while maintaining peak capacity.

Future Trends and Applications

Advancements may include coupling with high-resolution mass spectrometry for enhanced peptide identification, automation of sample preparation, and application to more complex biotherapeutics such as antibody-drug conjugates. Ongoing improvements in column technology and UHPLC system design will further increase throughput and sensitivity.

Conclusion

The Nexera-i UHPLC system combined with a core-shell peptide column provides a reproducible, high-resolution platform for antibody peptide mapping. Its stable gradient delivery and precise retention times make it a valuable tool for both research and quality control laboratories in biopharmaceutical development.

References

• Shimadzu Corporation. Application News No. L488, “Peptide Mapping of Antibody Drugs by Nexera-i,” 2015.