USP Method Transfer of Amoxicillin Oral Suspension from HPLC to UPLC

Importance of the Topic

Routine quality control of generically produced antibiotics such as amoxicillin is vital for ensuring safety and efficacy. Updating the official USP assay from conventional HPLC to modern UPLC techniques can dramatically improve laboratory efficiency, reduce solvent usage, and maintain high-quality analytical performance.

Objectives and Study Overview

This work demonstrates the transfer of the USP monograph method for amoxicillin oral suspension from HPLC to UPLC. The goals include preserving the monograph assay suitability criteria, increasing throughput, reducing solvent consumption, and evaluating long-term column robustness under routine use conditions.

Methodology and Instrumentation

This study first applied the USP HPLC method using an Alliance 2695 system with a µBondapak C18 equivalent XBridge Shield RP18 column (4.6×250 mm, 5 µm), isocratic mobile phase (98:2 phosphate buffer pH 5.0:acetonitrile), UV detection at 230 nm, 1.5 mL/min flow, 10 µL injection. The method was scaled to UPLC via the Waters Columns Calculator onto an ACQUITY UPLC BEH Shield RP18 column (2.1×100 mm, 1.7 µm) at 0.4 mL/min and 0.8 µL injection. Routine use was assessed by cycling standard and sample injections over 2400 runs.

Used Instrumentation

• Alliance 2695 HPLC system
• ACQUITY UPLC H-Class system
• XBridge Shield RP18 HPLC column (4.6×250 mm, 5 µm)
• ACQUITY UPLC BEH Shield RP18 column (2.1×100 mm, 1.7 µm)
• Empower 2 CDS software
• Waters Method Transfer Kit and Amoxicillin USP standard

Main Results and Discussion

Adoption of UPLC achieved a 70% reduction in run time (4.5 min vs. 15 min) and 92% lower solvent and sample consumption. Both HPLC and UPLC methods met USP criteria for retention time repeatability (%RSD < 0.5%), peak tailing (< 1.0), plate count (> 6000 for HPLC, > 15500 for UPLC), and retention factor. During a 2400-injection routine use study on the UPLC column, system pressure stabilized after a wash, and all assay suitability parameters remained within USP limits, confirming column robustness.

Benefits and Practical Applications

• Increased throughput for routine QC analyses
• Significant reduction in solvent and sample usage supports greener workflows
• Maintained compliance with USP monograph requirements
• Extended column lifetime with simple wash procedures

Future Trends and Applications

The integration of UPLC with compendial methods is expected to expand across pharmaceutical quality control, driving adoption of sub-2 µm stationary phases and automated method translation tools. Further developments may include coupling with mass spectrometry for impurity profiling and enhanced online monitoring in continuous manufacturing.

Conclusion

The successful transfer of the USP amoxicillin suspension assay from HPLC to UPLC offers a compelling case for modernizing compendial methods. The updated protocol delivers faster analysis, substantial resource savings, and enduring column performance, supporting high-throughput QC laboratories without compromising analytical requirements.

References

1. USP Monograph. Amoxicillin for Oral Suspension, USP34-NF29 [1886], United States Pharmacopeial Convention, 2011.
2. Jones M.D., Alden P., Fountain K.J., Aubin A. Implementation of Methods Translation between Liquid Chromatography Instrumentation, Waters Application Note 720003721EN, 2010.