Taking Advantage of 12k psi Pressure Capabilities for Modernizing USP Methods on the Alliance™ iS HPLC System

Significance of the Topic

Modernization of United States Pharmacopeia (USP) high-performance liquid chromatography (HPLC) methods is critical for pharmaceutical quality control. By adopting smaller particle columns and higher system pressures, laboratories can accelerate analyses, reduce solvent use, and align with green chemistry principles without compromising data integrity.

Objectives and Overview of the Study

This study aimed to apply USP General Chapter <621> scaling guidelines to legacy quetiapine fumarate assay and impurity methods. The original monograph conditions were evaluated on the Waters Alliance™ iS HPLC System and then scaled to a 3.0×150 mm and 3.0×100 mm column packed with 2.5 μm particles. Performance metrics and sustainability gains were compared between original and scaled methods.

Methodology

Method scaling followed USP <621> recommendations to maintain the column length-to-particle diameter ratio (L/dp). The Waters Columns Calculator estimated flow rates, injection volumes, and gradient times for the new column dimensions. System pressure limits guided final flow adjustments. Chromatographic parameters (resolution, tailing, retention time and area percent RSD) and quantitative accuracy for active pharmaceutical ingredient (API) and impurities were evaluated. The Analytical Method Greenness Score (AMGS) metric quantified sustainability improvements.

Used Instrumentation

• Waters Alliance iS PDA HPLC System (12,000 psi max pressure)
• Photodiode array detector (230 nm for assay, 250 nm for impurities)
• Empower Chromatography Data System

Main Results and Discussion

Scaling the isocratic quetiapine assay method to a 2.5 μm, 3 mm I.D. column reduced run time by 57% and solvent consumption by 71% while maintaining resolution, tailing factor and RSD criteria. The optimized flow rate (0.75 mL/min) remained below system pressure limits (~10,500 psi).
For the gradient impurity method, run time decreased by 51% and solvent use by 57% at 0.90 mL/min. Both original and scaled methods produced equivalent quantitative results for known and unknown quetiapine impurities. AMGS analysis showed a reduction in greenness score from 172 to 111, reflecting improved sustainability.

Benefits and Practical Applications

• Higher sample throughput and laboratory efficiency
• Significant solvent and waste reduction
• Maintained or improved chromatographic and quantitative performance
• Enhanced compliance with green chemistry objectives

Future Trends and Applications

Advances in ultra-high-pressure LC systems (beyond 12,000 psi) and novel column chemistries will further accelerate method modernization. Integration of real-time monitoring, automation, and AI-driven method development is expected to streamline lifecycle management. Wider adoption of greenness metrics will support sustainable analytical practices.

Conclusion

Applying USP <621> scaling to quetiapine fumarate assays on a high-pressure HPLC platform demonstrates that legacy compendial methods can be modernized effectively. The approach delivers faster analyses, reduced solvent consumption, and robust analytical performance, supporting both quality assurance and environmental goals.

References

1. United States Pharmacopeia. General Chapter <621> Chromatography. USP 40-NF35 S1; 2025.
2. United States Pharmacopeia. Quetiapine Fumarate Monograph. USP 40 NF35 S1; 2017:5939.
3. ACS Green Chemistry Institute Pharmaceutical Roundtable. Analytical Method Greenness Score. Accessed June 30, 2025.
4. Berthelette K.D., Walter T., Collins C., DeLoffi M., Haynes K. Applying Analytical Method Greenness Scoring to the USP Monograph of Naproxen. Waters Application Note; May 2024.
5. Waters Columns Calculator Online Help, version 2.0.
6. Dlugasch A.B., Simeone J., McConville P.R. Scaling a USP Gradient Method on the ACQUITY Arc System. Waters Application Note; July 2019.