Transfer of a compendial LC method for impurity analysis of chlorhexidine from a Waters Alliance HPLC system to a Vanquish Core HPLC system

Significance of the Topic

In pharmaceutical quality control, transferring validated chromatographic methods between different HPLC platforms ensures consistent impurity profiling across labs and instrument generations. Chlorhexidine, a widely used antiseptic, requires precise impurity analysis to meet pharmacopeial standards.

Goals and Overview of the Study

This study demonstrates the direct transfer of the European Pharmacopoeia monograph method for chlorhexidine impurity profiling from a Waters Alliance HPLC system to a Thermo Scientific Vanquish Core HPLC system, aiming for equivalent chromatographic results without extensive method revalidation.

Methodology and Instrumentation

• Column: Thermo Scientific Hypersil GOLD C18, 4.6 × 250 mm, 5 µm, end-capped
• Mobile phases: A) 0.1% TFA in water/acetonitrile (80/20 v/v); B) 0.1% TFA in water/acetonitrile (10/90 v/v)
• Gradient profile: 0–2 min: 0% B; 32–37 min: 20% B; 47–54 min: 30% B; 55–62 min: 0% B
• Flow rate: 1 mL/min; column temperature: 30 °C; autosampler temperature: 8 °C
• Detection: PDA at 254 nm (6 nm bandwidth), data rate 5 Hz, injection volume 10 µL
• Software: Thermo Scientific Chromeleon 7.3

Main Results and Discussion

• Retention time agreement: <4% difference between systems
• Relative retention times matched EP monograph targets within experimental error
• Resolution: Vanquish Core produced narrower peaks and higher resolution (e.g., impurity L–G pair ~8) compared to Alliance
• Repeatability: Vanquish Core RSD ≤0.04% (retention times) and ≤0.5% (peak areas); Alliance RSD up to 0.15% (times) and 2.8% (areas)
• Both systems easily met EP system suitability (resolution ≥3, peak-to-valley ≥2)

Benefits and Practical Applications of the Method

• Seamless method transfer without parameter changes
• Improved analytical performance on modern HPLC hardware
• Time and resource savings by avoiding full revalidation
• Applicable in R&D, QC, and inter-laboratory exchanges

Future Trends and Potential Applications

As chromatographic platforms evolve with lower dispersion and advanced mixing, future transfers may benefit from:

• Automated transfer workflows and predictive adjustment algorithms
• Integration of UHPLC and core–shell technologies for greater resolution
• High-throughput multi-analyte impurity profiling
• Standardized digital transfer protocols across instrument vendors

Conclusion

The EP monograph method for chlorhexidine impurity analysis was successfully transferred from a Waters Alliance to a Vanquish Core HPLC system, delivering equivalent or improved chromatographic outcomes. The Vanquish Core system enhanced resolution and repeatability while minimizing revalidation needs.

Reference

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5. European Pharmacopoeia. Monograph 0658: Chlorhexidine digluconate solution. 10th ed.; 2018.
6. World Health Organization. Model List of Essential Medicines. 21st ed.; 2019.
7. United States Pharmacopeial Convention. USP42-NF37: Chlorhexidine gluconate solution monograph. 2019.
8. Ph. Eur. Reference Standard: Chlorhexidine for system suitability CRS batch 2. European Directorate for the Quality of Medicines; 2019.