Transfer of an Isocratic USP Assay from an Agilent 1100 Series LC System to a ACQUITY UPLC H-Class System: Analysis of Tioconazole and Related Impurities

Significance of the Topic

Modern laboratories seek to upgrade legacy HPLC methods to UPLC platforms to improve efficiency, reduce solvent consumption and maintain compliance with pharmacopeial standards. Transferring established USP assays ensures continuity of quality control in pharmaceutical analysis while leveraging the advantages of advanced instrumentation.

Study Objectives and Overview

The primary goal was to migrate an isocratic USP monograph assay for tioconazole and its related organic impurities from an Agilent 1100 Series LC System to a Waters ACQUITY UPLC H-Class System. Key performance criteria included matching retention times, peak resolution, system suitability parameters and quantitation accuracy in line with USP requirements.

Methodology and Instrumentation

Both systems employed isocratic separation on reversed-phase C18 columns. The Agilent configuration used a 5 µm, 4.6 × 250 mm column at 0.75 mL/min with a 20 µL injection volume, passive pre-heater and diode array detection. The UPLC platform was fitted with a functionally equivalent column, a 50 µL sample loop, active pre-heater and a quaternary solvent manager. Mobile phase temperature control was applied on both systems. Detailed module lists for each system were recorded to ensure reproducibility.

Main Results and Discussion

• Retention times for tioconazole and three related impurities deviated by less than 2 % between systems, meeting the typical 3–5 % transfer criterion.
• Resolution of the critical impurity pair exceeded USP minimum of 1.4 on both instruments.
• Repeatability of retention time exhibited RSD values below 0.2 %, with marginally improved precision on the UPLC system.
• System suitability tests showed plate counts above 10 000 and tailing factors below 2.0 for the assay, satisfying USP limits.
• Quantitative impurity levels agreed within 0.01 %, and low-level peaks below 0.05 % were disregarded per USP guidelines.
• Baseline noise was higher on the Agilent HPLC but did not impact quantitation or compliance.

Benefits and Practical Applications

• Successful transfer enables laboratories to modernize equipment without redeveloping validated methods.
• UPLC implementation offers faster analysis and lower solvent use while preserving USP compliance.
• Maintaining comparable performance ensures reliability in quality assurance and regulatory submissions.

Future Trends and Applications

• Broader adoption of UPLC and UHPLC for pharmacopeial assays will accelerate throughput and reduce costs.
• Integration of automated method scouting and predictive software may streamline transfers.
• Miniaturized columns and green solvent systems will support sustainable analytical practices.
• Artificial intelligence could optimize separation conditions and system suitability in real time.

Conclusion

The study demonstrates that USP monograph methods for tioconazole can be seamlessly migrated from legacy HPLC to modern UPLC systems without compromising analytical integrity. Key performance metrics including retention consistency, resolution, precision and quantitation were maintained, facilitating laboratory modernization while upholding regulatory standards.

Reference

1. USP 37 NF32 S2, Official Monographs, Tioconazole and Organic Impurities.
2. Agilent Technologies, Easy Transfer of Standard HPLC Methods to Rapid Resolution Systems, 2006.
3. USP Chapter <621> Chromatography, USP 37 NF32 S1.
4. Agilent 1100 Series DAD and MWD Reference Manual, 2004.
5. Waters ACQUITY UPLC PDA Detector Specifications, 2014.