Easy transfer of an EP method for chlorhexidine impurity analysis from a Shimadzu Nexera-i system to a Vanquish Core HPLC system

Importance of the Topic

The reliable transfer of pharmacopeial liquid chromatography methods between different HPLC platforms is crucial for ensuring consistent quality control across laboratories. Chlorhexidine, a widely used antiseptic listed on the WHO Essential Medicines list, requires rigorous impurity profiling. Demonstrating a straightforward migration of an EP monograph method supports regulatory compliance and operational efficiency.

Objectives and Study Overview

This work aimed to move the European Pharmacopoeia method for chlorhexidine impurity analysis from a Shimadzu Nexera-i system to a Thermo Scientific Vanquish Core Quaternary system. Emphasis was placed on exploiting the Vanquish Core’s gradient delay volume (GDV) tuning features to minimize retention time differences and maintain chromatographic equivalence.

Methodology and Instrumentation

The EP monograph method employed a Hypersil GOLD C18 column (4.6×250 mm, 5 μm) with mobile phases A (0.1% TFA in water/acetonitrile 80/20) and B (0.1% TFA in water/acetonitrile 10/90). A linear gradient at 1 mL/min and column temperature of 30 °C was used. Detection was performed at 254 nm. Data acquisition and integration were managed in Chromeleon CDS 7.3.
Instrumentation:

• Shimadzu Nexera-i LC-2040C 3D: quaternary pump, autosampler, column oven, PDA detector
• Thermo Scientific Vanquish Core Quaternary: Quaternary Pump C, Split Sampler CT, Column Compartment C, Diode Array Detector
• Optional Method Transfer Kit (200 μL loop) and adjustable autosampler idle volume (0–230 μL)

Key Results and Discussion

• Chromatograms on both systems exhibited equivalent impurity profiles, matching EP retention parameters and exceeding system suitability: resolution > 8 (vs. minimum 3) and peak-to-valley ratio > 6 (vs. minimum 2).
• Precision improved on the Vanquish Core: retention time RSD ≤ 0.05% (vs. ≤ 0.09%) and peak area RSD < 0.5%.
• Small absolute retention time shifts (0.076–0.26 min) on the Vanquish Core were attributed to a lower default GDV.
• Adjusting the autosampler idle volume from 25 μL to 125 μL reduced average deviation from 0.132 min to 0.051 min, demonstrating compliant, traceable GDV tuning.

Benefits and Practical Applications

• Streamlines inter-instrument and inter-laboratory method transfers without extensive method revalidation.
• Enhances analytical precision, supporting tighter quality control criteria.
• Facilitates phased replacement of legacy systems with modern HPLC platforms.

Future Trends and Applications

Emerging HPLC designs will likely offer more automated and dynamic GDV adjustments, simplifying method migration even further. Integration of software-driven instrument calibration and AI-assisted method matching may enable real-time harmonization of chromatographic performance across sites.

Conclusion

The EP monograph HPLC method for chlorhexidine impurity analysis was successfully transferred from Shimadzu Nexera-i to Thermo Scientific Vanquish Core with equivalent chromatographic results and enhanced precision. The ability to fine-tune GDV via autosampler idle volume and optional transfer kit proves to be a powerful tool for compliant and efficient method migration.

References

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