Making safety decisions for a sunscreen active ingredient using next-generation risk assessment: Benzophenone-4 case study

The uptake of non-animal technologies has been slow for the evaluation of systemic toxicity in the cosmetic industry, even though regulatory bodies have approved them for endpoint assessment.

This study, conducted by a team at Unilever, demonstrates the feasibility of using New Approach Methodologies (NAMs) for the comprehensive safety assessment of 5% benzophenone-4 (BP-4) in sunscreen body lotion by combining in vitro models and advanced in silico methods. The researchers used the aProximate™ Proximal Tubule Cell (PTC) model to assess potential nephrotoxicity and renal transport kinetics, showing that the compound—UV filter benzophenone-4 (BP-4)—was safely excreted by the kidneys. The data, combined with advanced computational approaches, demonstrate that significantly higher exposures to the compound are required to trigger biological responses.

This work supports the drive toward standardization and paves the way for the implementation and acceptance of NAMs in regulatory chemical risk assessment.

Abstract

This study on the UV filter benzophenone-4 (BP-4) highlights the potential of modern, non-animal testing methods to provide comprehensive safety evaluations. It shows that BP-4, when applied in a sunscreen lotion, is poorly absorbed through the skin and efficiently excreted by the kidneys, resulting in low exposure to internal organs. The use of advanced computational and in vitro techniques revealed that most biological responses would only occur at levels significantly higher than predicted consumer exposure. This approach aligns with the 3Rs principle by reducing reliance on animal testing and offers a more ethical and potentially faster pathway for regulatory safety assessments. The findings suggest that next-generation risk assessments can effectively address safety concerns and pave the way for broader regulatory acceptance and implementation of these innovative methods.