Advanced Characterization of Semaglutideand Its Impurities Using a Heart-Cutting 2D-LC/MS Workflow for Biopharmaceutical Analysis

Significance of the Topic

Peptide therapeutics such as semaglutide play a critical role in treating type II diabetes and obesity. Their high potency and structural complexity require rigorous impurity profiling to guarantee product safety and efficacy under GMP conditions. Advanced analytical methods are essential to detect low-level variants, degradation products, and post-translational modifications that may coelute under conventional one-dimensional LC workflows.

Objectives and Overview of the Study

This study demonstrates a heart-cutting two-dimensional LC/MS workflow combining an orthogonal peptide separation and MS-compatible desalting step to characterize semaglutide and its related impurities. Key aims include resolving coeluting isoforms, identifying truncated and isomeric variants, and automating sequence confirmation using high-resolution mass spectrometry and dedicated bioinformatics.

Methodology and Instrumentation

The workflow integrates:

• Agilent 1290 Infinity III Bio 2D-LC system with multiple heart-cutting capability
• First dimension: AdvanceBio Peptide Plus column, phosphate buffer-based gradient at pH 4.5
• Second dimension: AdvanceBio RP-mAb C4 column with formic acid in water and acetonitrile for desalting and MS compatibility
• Agilent 6545XT AdvanceBio LC/Q-TOF with BioConfirm software for accurate mass and MS/MS acquisition
• High-resolution sampling strategy via multiple 40 µL loops and multi-inject to capture pre-main, main, and post-main peak regions

Main Results and Discussion

The two-dimensional approach effectively separated semaglutide from its truncated forms and isomeric impurities. HiRes heart-cuts enabled the detection of intact peptide, truncated fragments (such as 7–31 and 19–21), and low-abundance variants with mass tolerances of ±10 ppm (MS) and ±20 ppm (MS/MS). Automated BioConfirm processing facilitated confident sequence matching and PTM assignment.

Benefits and Practical Applications

• Enhanced resolution of coeluting peptide variants
• Improved throughput through multi-inject and automated sampling
• Accurate mass data for low-level impurity detection
• Seamless integration of chromatography and bioinformatics for method robustness

Future Trends and Potential Applications

Emerging trends include expanding heart-cutting workflows to complex biologics, integration with ion mobility separation for additional orthogonality, and advanced data analytics for deeper impurity profiling. The platform may be adapted to other therapeutic peptides and protein conjugates, supporting accelerated development and quality control.

Conclusion

This integrated heart-cutting 2D-LC/MS workflow provides a powerful tool for the comprehensive characterization of semaglutide and its impurities. By combining orthogonal separations, high-resolution MS, and automated sequence confirmation, the method enhances detection sensitivity, specificity, and throughput, addressing critical needs in biopharmaceutical analysis.

References

Khandpur P; Bharatiya P; Pargaonkar A. Advanced 2D-LC/Q-TOF Workflow for Impurity Characterization of GLP-1 Therapeutic Peptide Semaglutide. Agilent Technologies Application Note 5994-8288EN, 2025.