Analysis of Levofloxacin

Importance of the topic

Levofloxacin and ciprofloxacin are widely used fluoroquinolone antibiotics. Precise and reliable quantification of these compounds and their impurities is essential for pharmaceutical quality control and regulatory compliance. High‐performance liquid chromatography (HPLC) remains a cornerstone technique to ensure drug safety, efficacy, and purity assessments.

Study objectives and overview

This application note demonstrates a robust reversed‐phase HPLC method using a Shim-pack GIST C18 column for simultaneous analysis of levofloxacin, ciprofloxacin, and a specified impurity (Impurity E). The goal is to achieve clear baseline separation under isocratic conditions for routine QC laboratories.

Methodology

The method employs an isocratic mobile phase consisting of:

• Solvent A: 4.0 g ammonium acetate + 7.0 g sodium perchlorate + phosphoric acid in 1300 mL water (pH 2.2)
• Solvent B: Acetonitrile
• Ratio A : B = 85 : 15

Key chromatographic parameters:

• Flow rate: 0.8 mL/min
• Column temperature: 40 °C
• Injection volume: 10 µL
• Detection wavelength: 294 nm (UV)

Instrumentation

The analysis was carried out using:

• Shim-pack GIST C18 column (150 mm × 4.6 mm I.D., 3 µm; P/N: 227-30011-07)
• LabTotal™ Vial for LC/LCMS (P/N: 227-34001-01)

Main results and discussion

Chromatograms of a standard mixture containing levofloxacin (0.1 g/mL), ciprofloxacin (5 µg/mL), and Impurity E (5 µg/mL) in 0.1 mol/L HCl demonstrate well-resolved peaks. Retention times follow the order: Impurity E < Levofloxacin < Ciprofloxacin. Peak symmetry and reproducibility meet typical QC requirements, indicating stable separation under the chosen conditions.

Benefits and practical applications

• The isocratic method simplifies method development and reduces equilibration times.
• High resolution ensures reliable detection of low-level impurities.
• Straightforward mobile phase composition facilitates routine implementation in pharmaceutical QC environments.

Future trends and opportunities

• Expanding the method to multi-residue analysis of additional fluoroquinolones.
• Integration with mass spectrometry for enhanced sensitivity and impurity profiling.
• Exploration of greener solvents and shorter columns for faster analysis and reduced environmental impact.

Conclusion

The Shim-pack GIST C18 column combined with the described isocratic mobile phase provides an efficient, reproducible, and user-friendly approach to quantify levofloxacin, ciprofloxacin, and related impurities. This method meets quality control standards and can be readily adopted in pharmaceutical laboratories.

Reference

• Shimadzu Corporation. Analysis of Levofloxacin using Shim-pack GIST C18. ERAS-1000-0068, First Edition Mar. 2023.