Raman Spectroscopy to Monitor Post-Translational Modifications and Degradation in Monoclonal Antibody Therapeutics.

Area of Science:

• Biopharmaceutical analysis
• Protein characterization
• Spectroscopic techniques

Background:

• Monoclonal antibodies (mAbs) are vital biotherapeutics, but structural changes can compromise efficacy and safety.
• Current characterization methods lack the speed and in-situ capabilities needed for real-time manufacturing monitoring.
• Raman spectroscopy offers a water-insensitive, minimally invasive, and rapid analytical approach for protein analysis.

Purpose of the Study:

• To evaluate Raman spectroscopy for detecting post-translational modifications (PTMs) and degradation in monoclonal antibodies (mAbs).
• To assess the applicability of Raman spectroscopy for in-line monitoring during biopharmaceutical manufacturing.
• To correlate specific Raman spectral features with identified PTMs and degradation states.

Main Methods:

• Incubation of IgG4 antibodies under various stress conditions (pH, temperature, agitation, photo, chemical).
• Characterization of aggregation using size-exclusion chromatography and PTMs via peptide mapping.
• Combined analysis of Raman spectroscopy, circular dichroism (CD) spectroscopy, and principal component analysis (PCA).

Main Results:

• Principal component analysis successfully separated proteins based on PTMs and degradation states.
• Specific Raman spectral bands were correlated with particular PTMs, including tryptophan oxidation.
• A linear correlation was established between Raman peak wavenumbers and the extent of IgG4 aggregation.

Conclusions:

• Raman spectroscopy is a viable tool for identifying and quantifying PTMs and degradation in mAbs.
• The technique demonstrates potential for real-time, in-line monitoring in biopharmaceutical production.
• Raman spectroscopy can enhance quality control and process understanding for therapeutic protein manufacturing.