Is o-Phenylphenol Safe for Cosmetics? SCCS Releases Detailed Report

Findings on Dermal Absorption

A significant area covered in the report is the dermal absorption of OPP. Multiple studies indicate that OPP is rapidly absorbed through human skin, with an absorption rate of approximately 43%. This finding is critical as it highlights the efficiency of skin absorption and the subsequent excretion process. The majority of the absorbed substance is excreted through urine within the first 24 hours, effectively minimising the risk of systemic accumulation. The rapid excretion is further supported by studies involving human volunteers where radiolabelled OPP was applied topically. The results showed that most of the absorbed dose was recovered in the urine, underscoring the body's ability to eliminate OPP efficiently.

Detailed Toxicological Evaluation

The report includes a comprehensive toxicological evaluation of OPP and its salts, focusing on several key aspects:

Irritation and Corrosivity

The studies reviewed in the report demonstrate that OPP and its salts can cause significant skin and eye irritation. The undiluted forms of these compounds are particularly concerning, as they can be highly irritating or even corrosive to the skin and eyes. This highlights the importance of using these substances in controlled concentrations to avoid adverse effects.

Skin Sensitisation

The potential for skin sensitisation is another crucial aspect of the toxicological evaluation. The SCCS report concludes that OPP and its salts have a low potential for skin sensitisation. This conclusion is based on animal studies that, despite some deviations from OECD guidelines, showed no significant sensitisation potential. Furthermore, human studies indicate a low frequency of sensitisation, primarily observed in occupational settings rather than general cosmetic use. This suggests that, under normal usage conditions, the risk of skin sensitisation from OPP is minimal.

Carcinogenicity

Chronic toxicity and carcinogenicity studies have identified the urinary bladder and kidneys as primary target tissues for OPP and SOPP in mice and rats. The mode of action for bladder carcinogenesis is thought to involve chronic irritation of the epithelium due to factors such as high urinary pH and the presence of free metabolites. These findings are critical for understanding the long-term risks associated with exposure to these compounds.

Safety and Regulatory Recommendations

Based on the findings of the report, the SCCS concludes that OPP is safe for use as a preservative in cosmetic products up to a maximum concentration of 0.2% in rinse-off products and 0.15% in leave-on products. This safety assessment also applies to the combined use of OPP and SOPP, which should not exceed these concentrations in cosmetic formulations. The detailed recommendations provided by the SCCS are intended to guide manufacturers in formulating safe cosmetic products and help regulatory bodies enforce appropriate safety standards.

Conclusion

The detailed evaluation by the SCCS provides a nuanced and comprehensive understanding of the safety profile of o-Phenylphenol and its salts in cosmetic products. While certain risks such as skin irritation and potential carcinogenicity in specific contexts are noted, the controlled use of these compounds within specified concentration limits is deemed safe for consumers. The findings underscore the importance of adhering to recommended concentration limits to mitigate potential health risks.

This report serves as an essential reference for cosmetic manufacturers and regulatory bodies, ensuring the safe formulation and use of preservatives in cosmetic products. By following the SCCS's guidance, the industry can continue to provide safe and effective products to consumers, maintaining public trust and compliance with regulatory standards.