A Scaled USP Method for Fluconazole Using an ACQUITY UPLC I-Class System and CORTECS T3 Column Chemistry

Significance of the Topic

The ability to efficiently separate fluconazole and its related impurities is vital for ensuring pharmaceutical safety and compliance with regulatory standards. Scaling traditional HPLC methods to modern UPLC techniques can substantially reduce analysis time and solvent consumption while maintaining or improving resolution and sensitivity.

Study Objectives and Overview

This work describes the adaptation of a United States Pharmacopeia (USP) monograph method for fluconazole to an ultra performance liquid chromatography (UPLC) format using sub-2 µm superficially porous particles. The primary goals were to shorten run times, lower solvent usage, and achieve or exceed the system suitability requirements defined by the USP.

Methodology and Instrumentation

The study involved:

• Sample preparation in accordance with the USP monograph: fluconazole and related compounds dissolved in acetonitrile and diluted in 80:20 water:acetonitrile to 10 µg/mL.
• Instrumental setup: Waters ACQUITY UPLC I-Class System with PDA detection, Empower 3 FR2 software, and Waters Columns Calculator for method scaling.
• Columns evaluated: CORTECS UPLC C18+ (1.6 µm, 2.1 × 75 mm), CORTECS UPLC T3 (1.6 µm, 2.1 × 75 mm), and ACQUITY UPLC HSS T3 (1.8 µm, 2.1 × 75 mm).
• Chromatographic conditions: isocratic 80:20 water:acetonitrile, 40 °C, flow rates of 0.228 mL/min (solid-core) or 0.203 mL/min (fully porous), injection volumes of 1.5–2.1 µL, detection at 260 nm.

Main Results and Discussion

Scaling from a 3.5 µm, 4.6 × 150 mm column to a 1.6 µm, 2.1 × 75 mm column increased the L/dp ratio by 9.4%—well within the USP’s ± tolerances—and reduced run time from 10 minutes to ~2 minutes. Among the columns tested, the superficially porous CORTECS UPLC T3 provided baseline separation of all critical peak pairs, meeting resolution ≥1.5 and RSD ≤5% for retention time and area. Compared to a fully porous HSS T3 column, the solid-core T3 chemistry yielded narrower peak widths, earlier elution, and up to 30% higher efficiency for later eluting impurities.

Benefits and Practical Applications

By applying UPLC scaling principles and solid-core column technology, laboratories can achieve:

• Substantial reductions in analysis time and solvent usage.
• Improved chromatographic efficiency and peak capacity.
• Robust compliance with USP system suitability criteria.
• Enhanced selectivity for polar and nonpolar impurities.

Future Trends and Potential Applications

Advances in column chemistries, automation tools, and data-driven method transfer are expected to further streamline USP method scaling. Integration of eco-friendly solvents and high-throughput platforms will support sustainable, cost-effective quality control across the pharmaceutical industry.

Conclusion

This study demonstrates that scaling USP monograph methods to UPLC using CORTECS superficially porous particles delivers significant improvements in throughput, solvent economy, and chromatographic performance without sacrificing regulatory compliance.

References

1. United States Pharmacopeia and National Formulary. Chapter <621> Chromatography, USP 37-NF 32 S2; 2014:6376–6385.
2. Snyder LR, Kirkland JJ, Dolan JW. Introduction to Liquid Chromatography. 3rd ed. Wiley; 2010.
3. United States Pharmacopeia and National Formulary. Official Monographs: Fluconazole, USP 37-NF 32 S2; 2014:4968.