High-Speed and Simultaneous Analysis of Active Ingredients CPC and GK2 in Mouthwash

Importance of the Topic

Quality control and routine monitoring of active ingredients in oral care products are essential for ensuring consumer safety, regulatory compliance and product efficacy. Cetylpyridinium chloride (CPC) and dipotassium glycyrrhizinate (GK2) serve distinct roles in mouthwash formulations, offering antimicrobial and anti-inflammatory effects respectively. A fast, reliable method for their simultaneous quantification addresses laboratory throughput challenges and avoids the complications associated with ion-pairing reagents.

Objectives and Study Overview

The primary goal of this study was to establish a high-speed chromatographic method for simultaneous determination of CPC and GK2 in mouthwash. Utilizing a Shimadzu Nexera XR UHPLC system equipped with a Shim-pack Arata C18 column, the method aimed to achieve baseline separation and quantitation within a four-minute runtime, eliminating the need for ion-pairing additives or perchlorate salts.

Methodology and Instrumentation

Analytical conditions were optimized as follows:

• Chromatograph: Nexera XR
• Column: Shim-pack Arata C18, 75 × 3.0 mm I.D., 2.2 µm
• Mobile phase: A) 0.1 % formic acid in water, B) 0.1 % formic acid in acetonitrile
• Gradient: 40 % B at start → 50 % B at 4.00 min → return to 40 % B at 4.51 min
• Flow rate: 1.0 mL/min; Column temperature: 40 °C; Injection volume: 1 µL
• Detection: Photodiode array at 254 nm

Main Results and Discussion

A sharp, symmetrical peak for CPC was obtained without peak tailing, despite its basic nature. Repeatability studies (n = 6) yielded relative standard deviations ≤ 0.6 % for both retention time and peak area. Calibration was linear from 5 to 200 mg/L, with correlation coefficients (r2) ≥ 0.9999. Application to two commercial mouthwash samples demonstrated accurate quantitation of CPC (23.1 and 44.7 mg/L) and GK2 (143.6 and 22.4 mg/L) following simple ten-fold dilution and filtration. UV spectra acquired by PDA confirmed peak identities through matching absorption maxima.

Benefits and Practical Applications

• Rapid throughput: complete separation within four minutes.
• Elimination of ion-pairing reagents reduces method complexity and maintenance issues.
• Excellent repeatability and linearity support robust quality control workflows.
• Simple sample preparation suitable for routine analysis in research, QA/QC and industrial laboratories.

Future Trends and Potential Applications

Advances may include extending the approach to other quaternary ammonium surfactants or related cationic compounds. Integration with mass spectrometry could enhance sensitivity and selectivity. Further miniaturization of column formats and exploration of greener mobile phase alternatives align with sustainability initiatives. Automated sample preparation and real-time monitoring in production environments represent promising extensions.

Conclusion

A high-speed, simultaneous HPLC method for CPC and GK2 has been developed on a Nexera XR system with Shim-pack Arata C18. The approach delivers reliable quantitation in under four minutes without ion-pairing agents, supporting efficient quality control of mouthwash formulations.

References

No external literature references were provided in the original text.