Chiral separation of Naproxen (6-Methoxy-α-Methyl-2- Naphthylessigsäure)

Importance of the Topic

The enantiomeric purity of Naproxen, a widely used nonsteroidal anti-inflammatory drug, is critical due to distinct pharmacological effects of its stereoisomers. Chiral separation techniques ensure accurate dosage, efficacy and safety in pharmaceutical analysis.

Objectives and Study Overview

This study aimed to develop and optimize an isocratic chiral HPLC method for baseline resolution of Naproxen enantiomers using a cellulose-based stationary phase. Key goals included assessing selectivity, retention behavior and robustness of the method.

Used Instrumentation

• HPLC system equipped with UV detector at 230 nm
• Chiral column: Eurocel 01, 5 µm particle size, 250 × 4.6 mm ID (Order No. 25EM370ECJ)

Methodology and Instrumentation

The mobile phase consisted of hexane/2-propanol (90:10) with 0.1% trifluoroacetic acid under isocratic conditions. Flow rate was set to 1.0 mL/min, column temperature maintained at 25 °C and injection volume at 10 µL. Enantiomers were detected via UV absorption at 230 nm.

Main Results and Discussion

Baseline separation of the two Naproxen enantiomers was achieved with retention factors of k'1 = 0.97 and k'2 = 1.17, yielding a selectivity factor (α) of 1.21. The cellulose-based selector provided distinct interaction differences driving enantioselectivity. Chromatogram evaluation demonstrated sharp peaks and adequate resolution for quantitative analysis.

Benefits and Practical Applications of the Method

• Suitable for quality control of Naproxen formulations
• Enantiomeric purity assessment in pharmaceutical development and regulatory compliance
• Robust and reproducible protocol for routine laboratory use

Future Trends and Applications

Advances in chiral stationary phases and greener mobile phases may further improve resolution and reduce solvent consumption. Integration with mass spectrometry and high-throughput automation can enhance sensitivity and speed for complex sample matrices.

Conclusion

The developed chiral HPLC method offers reliable baseline separation of Naproxen enantiomers, demonstrating robustness and practical applicability in pharmaceutical analysis.