Transferring the USP Assay of Zidovudine Using CORTECS 2.7 μm Columns

Significance of the Topic

With the pharmaceutical industry facing increasing pressure to optimize laboratory productivity and reduce costs, streamlining compendial assays has become essential. By transferring established USP methods to more efficient stationary phases, analytical chemists can achieve faster turnaround times, lower solvent consumption, and maintain regulatory compliance.

Objectives and Study Overview

The study aimed to demonstrate the transfer of the USP assay for Zidovudine, an antiretroviral drug, from a traditional 5 µm, 4.6×250 mm column to two CORTECS C18 solid core columns (2.7 µm, 4.6×150 mm and 2.7 µm, 4.6×100 mm) under the guidelines of USP General Chapter 621. Two transfer approaches were evaluated: maintaining column length to particle diameter ratio L/dp and preserving theoretical plate count N.

Methodology and Instrumentation

Sample Preparation

• Zidovudine and related compounds prepared at specified concentrations in methanol

Analytical Conditions

• Mobile phase isocratic 80 20 water to methanol
• Detection UV 265 nm
• Temperature 30 °C
• Flow rates 1.0 mL/min 4.6×250 mm, 0.9 mL/min 4.6×150 mm, 1.5 mL/min 4.6×100 mm

Used Instrumentation

• Alliance HPLC
• Empower 3 CDS
• LCMS Certified Max Recovery Vials
• Neutrals Quality Control Reference Material

Results and Discussion

System performance was monitored using Neutrals QCRM before and after sample analysis, confirming consistent retention and peak shape across all columns. Using the L/dp transfer with the 150 mm column reduced cycle time by 50 and solvent use by 50 while meeting USP system suitability criteria for resolution, tailing, and retention time precision. For the N based transfer with the 100 mm column, the theoretical plate count fell within the allowed range, enabling a 75 reduction in analysis time and 63 solvent savings, again satisfying monograph requirements.

Benefits and Practical Applications

• Up to 75 reduction in analysis time
• Up to 63 reduction in solvent usage
• No method revalidation required under USP General Chapter 621
• Enhanced laboratory throughput and cost efficiency

Future Trends and Opportunities

Adoption of solid core particle columns is poised to expand across pharmaceutical QAQC laboratories. Future work may explore method transfers for additional compendial assays, automation of system performance checks with QCRM, and continued refinement of chromatographic guidelines to support high throughput and green analytical chemistry.

Conclusion

The successful transfer of the Zidovudine USP assay to CORTECS C18 2.7 µm columns demonstrates the potential for significant productivity gains and solvent savings without revalidation. Implementation of these strategies can accelerate pharmaceutical testing and reduce environmental impact.

Reference

1. USP Monograph Zidovudine USP NF
2. General Chapter 621 Chromatography USP NF
3. Berthelette K Summers M Fountain K Troubleshooting Common System Problems Using Waters Neutrals Quality Control Reference Material Waters Application Note 720004635EN 2013