Determination of Ten Active Ingredients in Sunscreen-Containing Products in a Single Injection

Importance of Determining Sunscreen Actives in Skincare

The widespread incorporation of UV-absorbing compounds in cosmetics and personal care products plays a critical role in protecting skin from harmful solar radiation. Reliable analytical methods are essential for product safety, regulatory compliance, and quality assurance across the cosmetics industry.

Objectives and Study Overview

This study aimed to develop a single-injection, high-resolution reversed-phase HPLC method for simultaneous separation and quantification of ten FDA-approved sunscreen actives. The target analytes included 2-phenylbenzimidazole-5-sulfonic acid (PHS), benzophenone-3 (B-3), diethylamino-hydroxybenzoylhexyl benzoate (DHHB), 4-methylbenzylidene-camphor (4-MBC), octocrylene (OCR), methyl-anthranilate (MA), octyl-methoxycinnamate (OMC), butyl-methoxydibenzoylmethane (BMDM), octyl-salicylate (OS), and homosalate (HMS).

Methodology and Used Instrumentation

• Instrument: Dionex UltiMate 3000RS chromatography system with SRD-3600 solvent rack, HPG-3400RS binary pump, WPS-3000RS sampler, TCC-3000RS column compartment, DAD-3000RS diode array detector, controlled by Chromeleon CDS.
• Column: Acclaim 120 C18, 3 µm, 4.6 × 100 mm.
• Mobile phase: A = 0.8% acetic acid in water; B = ethanol; gradient from 25% to 80% B over 1.5 min, hold to 11.5 min.
• Flow rate: 0.7 mL/min; column temperature: 25 °C; injection volume: 5 µL.
• Detection: UV at 310 nm for eight compounds and 354 nm for two compounds, plus spectral scanning (250–600 nm) for peak purity.
• Standards: 1000 mg/L individual stock solutions in methanol; mixed working standards at 10–75 mg/L.
• Sample prep: 0.1 g of product extracted in 70 mL methanol with ultrasound, diluted to 100 mL, and filtered through 0.2 µm nylon.

Results and Discussion

• Separation: All ten analytes baseline resolved (USP resolution >2.5) within 12 minutes using an ethanol/acetic acid gradient.
• Calibration: Linear dynamic range 10–75 mg/L with R² ≥ 0.998 for all compounds.
• Precision and Purity: Retention time RSD < 1% and peak purity index RSD < 1% confirmed robustness and absence of co-elution.
• Recovery: Mean recoveries ranged from 98% to 107% in cosmetic powder, lotion, and lipstick placebo matrices spiked at 35 mg/L.
• Sample Analysis: Cosmetic powder contained MA, OMC, and OS at approximately 1–3% w/w; lotion contained PHS, B-3, 4-MBC, OMC, OS, and HMS at 1–3% w/w; lipstick contained eight actives (including trace DHHB at ~0.03% w/w) in the 0.03–3.4% w/w range.

Benefits and Practical Applications

This rapid, high-throughput HPLC-DAD method enables comprehensive profiling of multiple sunscreen filters in a single injection, making it highly suitable for routine quality control, regulatory testing, and formulation development.

Future Trends and Opportunities

• Extension to additional UV filters approved in European and Asian markets.
• Integration with mass spectrometry for enhanced sensitivity and selectivity.
• Implementation of automated sample preparation or online SPE for workflow efficiency.
• Adoption of greener mobile phases or solvent-reducing technologies for sustainable analysis.

Conclusion

An Acclaim 120 C18 column on the UltiMate 3000 system achieves baseline separation and accurate quantification of ten sunscreen actives in under 12 minutes, demonstrating excellent precision, accuracy, and applicability across diverse cosmetic matrices.

References

• Application Note 223, Determination of Ten Active Ingredients in Sunscreen-Containing Products, Dionex Corporation, 2016.