Qualification of FTIR spectroscopic method for protein secondary structural analysis

Area of Science:

• Biophysical Chemistry
• Spectroscopy
• Protein Science

Background:

• Fourier transform infrared (FTIR) spectroscopy is utilized for protein secondary structure analysis.
• The biopharmaceutical industry employs FTIR for characterizing protein therapeutics' higher-order structure.
• FTIR is used to detect conformational changes due to process, formulation, or storage variations.

Purpose of the Study:

• To quantitatively assess the precision and sensitivity of FTIR spectroscopy for protein characterization.
• To validate FTIR as a suitable method for regulatory filings in the biopharmaceutical industry.
• To demonstrate the method's capability beyond qualitative comparability assessments.

Main Methods:

• Evaluation of the precision of FTIR spectroscopic analysis through replicate measurements.
• Assessment of method sensitivity in detecting structural changes induced by pH and denaturants.
• Analysis of spectral similarity and characteristic FTIR bands to quantify structural alterations.

Main Results:

• FTIR spectroscopic analysis demonstrated high reproducibility, with spectral similarity of replicate measurements exceeding 90%.
• The method successfully detected secondary structural changes induced by variations in pH and denaturant concentration.
• Method sensitivity was found to be dependent on the extent of structural changes and their spectral impact.

Conclusions:

• FTIR spectroscopy is a reproducible and sensitive method for characterizing protein higher-order structure.
• The findings support the quantitative application of FTIR in biopharmaceutical characterization and regulatory submissions.
• FTIR provides a valuable tool for assessing protein conformational stability and comparability.