Successful and Stress-Free LC Method Transfers

Significance of the topic

Reliable transfer of pharmacopeial HPLC methods between instruments is essential for regulated laboratories, enabling consistent quality control across R&D, QC, and contract environments without extensive requalification. As laboratories modernize or adopt new hardware, maintaining equivalence in retention, resolution, and precision minimizes downtime and supports global method harmonization.

Objectives and study overview

This work demonstrates the seamless transfer of the European Pharmacopoeia method for impurity profiling of chlorhexidine digluconate, originally developed on a Waters Alliance HPLC system, to a Thermo Scientific Vanquish Core HPLC system. Key performance metrics—relative retention, peak symmetry, resolution, and repeatability—are compared to ensure compliance with monograph criteria.

Methodology and instrumentation

Both systems employed identical chromatographic conditions following EP monograph 0845:

• Column: Hypersil GOLD C18, 250 × 4.6 mm, 5 µm, end-capped silica
• Mobile phase A: 0.1% TFA in 80/20 water/acetonitrile; B: 0.1% TFA in 10/90 water/acetonitrile
• Gradient: 0–2 min at 0% B; 2–32 min to 20% B; 32–37 min at 20% B; 37–47 min to 30% B; 47–54 min at 30% B; 54–55 min down to 0% B; 55–62 min re-equilibration
• Flow rate: 1.0 mL/min; column temperature: 30 °C (forced-air oven); sampler: 8 °C;
• Detection: 254 nm, 6 nm bandwidth, 1 s response, 5 Hz collection, 10 µL injection

Main results and discussion

Chromatograms from both instruments overlaid closely, with all twelve specified impurities and seven additional peaks resolved. Relative retention times matched the EP monograph within 2%, confirming equivalent elution order. Relative peak areas were within 5% of the reference ratios. The Vanquish Core system delivered narrower peaks and higher resolution in 80 % of impurity pairs, attributed to its reduced extra-column volume. System repeatability (RSD of peak areas) improved by 20 %–40 % on Vanquish Core compared to Alliance, demonstrating greater precision.

Benefits and practical applications

• Rapid adoption of compendial methods on modern HPLC platforms without altering pharmacopoeial protocols
• Improved peak capacity and resolution support detection of minor impurities near regulatory thresholds
• Enhanced precision reduces retesting and streamlines batch release
• Centralized software control and audit-trail compliance facilitate 21 CFR Part 11 requirements

Future trends and potential uses

Ongoing developments in automated method transfer tools, unified chromatography software, and smart instrumentation will further simplify cross-platform method migration. Integration of machine-learning-based parameter optimization could enable predictive adjustment of system volumes and gradients to ensure consistent results. Compact UHPLC columns coupled with low-dispersion flow paths will drive faster, higher-resolution methods across multi-site laboratories.

Conclusion

The EP monograph method for chlorhexidine impurity analysis was successfully transferred from a Waters Alliance HPLC to a Vanquish Core HPLC system. Equivalent retention behavior was achieved with superior resolution and improved quantitative precision on the Vanquish platform, demonstrating its suitability for regulated compendial workflows.

References

• European Directorate for the Quality of Medicines & HealthCare. European Pharmacopoeia Online, 9th ed. Monograph 0845: Chlorhexidine.
• Thermo Fisher Scientific. Application Note 73310: Transfer of a compendial LC method for impurity analysis of chlorhexidine from a Waters Alliance HPLC system to a Vanquish Core HPLC system.