Analysis of Levocarnitine Oral Liquid (Shim-pack Scepter Diol-HILIC-120)

Significance of the topic

The reliable quantification of levocarnitine and detection of anthraquinone impurities in oral liquid formulations is essential for regulatory compliance and patient safety. Hydrophilic interaction liquid chromatography (HILIC) provides strong retention and separation of highly polar compounds, addressing the challenges of conventional reversed-phase methods.

Objectives and study overview

This application note evaluates an isocratic HILIC method using a diol-based stationary phase to separate levocarnitine from its impurity A and an anthraquinone standard (aloe-emodin). Key goals include method robustness, sensitivity, and suitability for routine quality control.

Methodology and instrumentation

Pretreatment procedure involves protein precipitation with acetonitrile:

• Standard: mix 200 μL of 2 mg/mL levocarnitine solution and 3 μL of 0.5 mg/mL impurity A, add 800 μL acetonitrile
• Sample: mix 300 μL of levocarnitine oral liquid (2 mg/mL), add 700 μL acetonitrile

Chromatographic conditions:

• Column: Shim-pack Scepter Diol-HILIC-120 (250 x 4.6 mm, 5 μm)
• Mobile phase: 20 mmol/L KH2PO4 buffer with phosphoric acid (pH 4.35) and acetonitrile (25:75, v/v)
• Flow rate 1.0 mL/min; Column temperature 30 °C; Injection volume 20 μL; Detection UV at 205 nm
• Vials: LabTotal Vials for LC/LCMS

Main results and discussion

The diol-HILIC column achieved baseline separation of aloe-emodin and impurity A, with sharp and symmetric peaks observed in both standard and sample chromatograms. Recoveries of levocarnitine and impurity A exceeded 98%, and the method demonstrated excellent repeatability (RSD <1.5%). No significant matrix interferences were observed in the oral liquid formulation.

Benefits and practical application of the method

This HILIC-based approach offers rapid analysis with minimal sample preparation, high sensitivity for trace impurities, and robust performance for routine QC of levocarnitine oral products. The isocratic elution simplifies system equilibration and enhances throughput.

Future trends and potential applications

Advances in HILIC stationary phases and coupling with mass spectrometry promise further improvements in sensitivity and selectivity. This method format can be extended to other polar drug substances and related impurity profiling.

Conclusion

The presented HILIC-120 diol method provides a reliable, sensitive, and efficient solution for the simultaneous quantification of levocarnitine and detection of anthraquinone impurities in oral liquid formulations. It meets regulatory requirements and supports high-throughput QC workflows.

References

• Shimadzu Corporation – Analysis of Levocarnitine Oral Liquid using Shim-pack Scepter Diol-HILIC-120; ERAS-1000-0046; First Edition Mar. 2023