ATR-FTIR spectroscopy with multivariate analysis effectively monitors semaglutide and liraglutide degradation and secondary structure transitions

Therapeutic peptides are vital biomolecules, yet their structural complexity makes them highly susceptible to degradation, posing significant analytical challenges for quality control and formulation development. Traditional methods for monitoring peptide stability can be time-consuming and destructive. There is a critical need for rapid, non-destructive analytical tools to assess structural integrity and degradation pathways, particularly for compounds like semaglutide and liraglutide, which are widely used for metabolic disorders. Understanding these changes is crucial for ensuring product efficacy and safety throughout their lifecycle.

Researchers evaluated attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy coupled with multivariate data analysis to monitor degradation in peptide formulations. They used semaglutide and liraglutide as model compounds, preparing dry film samples. These samples were subjected to various stress conditions to induce degradation. Spectral data were collected using ATR-FTIR, focusing on the amide region I for secondary structure analysis. Principal Component Analysis (PCA) was applied to identify clustering patterns and classify samples. Results were complemented and validated by liquid chromatography-high-resolution mass spectrometry (LC-HRMS).

The integrated ATR-FTIR and multivariate analysis approach successfully detected subtle conformational changes in both semaglutide and liraglutide formulations. These changes were particularly evident in the amide region I, which is directly indicative of secondary structure alterations. PCA enabled clear identification of clustering patterns, effectively classifying samples based on different stress conditions and degradation stages. Analysis of loading and contribution line plots pinpointed the specific spectral features most contributing to variance, indicating early and advanced phases of degradation. Despite using a dry film approach and relatively short incubation times, the method demonstrated robust detection capabilities. > The ATR-FTIR results showed strong consistency with complementary LC-HRMS data, confirming the method's reliability in identifying structural alterations and degradation products.