High-speed analysis of Active Ingredients in Mouthwash

Significance of the Topic

Mouthwash formulations often include multiple active antimicrobial and anti-inflammatory agents to maintain oral hygiene and health. Reliable quantification of these components is essential for quality control, regulatory compliance, and consumer safety. High-speed chromatographic methods reduce analysis time and resource consumption while maintaining accuracy and precision.

Objectives and Study Overview

This study describes a rapid reversed-phase liquid chromatography method for simultaneous determination of dipotassium glycyrrhizate (GK2), cetylpyridinium chloride (CPC), and isopropyl methylphenol (IPMP) in mouthwash products. The goal is to achieve baseline separation within a short run time (<7 minutes) with robust performance suitable for routine quality control.

Methodology

• Column: Shim-pack Arata C18, 75 mm × 3.0 mm i.d., 2.2 μm
• Mobile Phase: A) 20 mmol/L sodium phosphate buffer (pH 2.6), B) methanol; gradient from 60% B to 80% B (0–4.50 min) returning to 60% B (4.51–7.00 min)
• Flow Rate: 0.8 mL/min; Column Temperature: 45 °C
• Detection: UV at 250 nm (GK2), 258 nm (CPC), 280 nm (IPMP)
• Injection Volume: 5 μL; Mixer Volume: 180 μL

Used Instrumentation

• Shimadzu Nexera XR UHPLC system
• SPD-M40 UV detector with standard cell
• Shimadzu LabTotal™ glass vials (1.5 mL)

Main Results and Discussion

The developed method achieved clear separation of GK2, CPC, and IPMP within 7 minutes with resolution factors >1.5. Retention times were reproducible (RSD <1.0%) across multiple injections. Calibration curves for each analyte were linear over the tested concentration range (5–100 mg/L) with correlation coefficients (r2) exceeding 0.999. Method precision and accuracy met industry standards for quantitative analysis.

Benefits and Practical Applications

• High sample throughput for routine quality control laboratories
• Reduced solvent consumption and analysis time
• Reliable performance for regulatory compliance in oral care product manufacturing

Future Trends and Possibilities

Advancements in UHPLC and sub-2 µm particle columns can further shorten run times and enhance resolution. Emerging detection technologies such as mass spectrometry enable multi-residue screening and structural confirmation. Adoption of green chemistry principles may lead to alternative solvents and buffer systems to minimize environmental impact.

Conclusion

The presented high-speed LC method provides an efficient, accurate, and robust approach for simultaneous quantification of key active ingredients in mouthwash, supporting quality assurance and regulatory requirements in oral care product analysis.

References

• Shimadzu Corporation. Application News an_01-00505 (JP, ENG), 2023.