As regulatory scrutiny round ingredient security intensifies, particularly relating to salicylate publicity and its conversion to salicylic acid, strong information on dermal absorption has develop into more and more essential. In response to a Scientific Committee on Client Security (SCCS) inquiry and industry-wide discussions, the Analysis Institute for Perfume Supplies (RIFM) performed an in vitro research inspecting the pores and skin absorption of ethyl salicylate, pentyl salicylate, and (Z)-3-hexenyl salicylate—three extensively used perfume elements.
CosmeticsDesign spoke with Dr. Kaushal Joshi, Principal Scientist at RIFM, concerning the research’s findings and what they imply for formulators, security assessors, and regulators navigating evolving requirements in beauty product improvement.
CDU: What prompted this research, and why deal with these explicit salicylates?
Dr. Kaushal Joshi: Salicylates are extensively utilized in perfume formulations throughout many shopper merchandise, however till now, there was restricted pores and skin absorption information for a number of of those compounds. It was initiated attributable to an SCCS inquiry and discussions from a working group led by Cosmetics Europe.
Moreover, with elevated regulatory deal with salicylate publicity from beauty and private care merchandise, particularly its conversion to salicylic acid, we noticed a must generate high-quality, human-relevant information. Ethyl salicylate, pentyl salicylate, and (Z)-3-hexenyl salicylate have been chosen as a result of they’re generally used and symbolize totally different structural variations, permitting us to discover how construction impacts pores and skin permeation.
CDU: One of many key takeaways was the impression of occlusion. Are you able to elaborate on that?
Dr. Joshi: Completely. Usually, occlusion is taken into account a extra conservative method.
We examined every salicylate below unoccluded and occluded circumstances, simulating eventualities like a cream being left open to air versus being coated over with a bandage. Throughout the board, occlusion elevated permeation.
For instance, ethyl salicylate absorption almost doubled below occlusion. This reinforces how real-world use circumstances can considerably have an effect on publicity ranges, essential for correct security assessments.
CDU: You additionally tracked salicylic acid as a degradation product. Why was that essential?
Dr. Joshi: Whereas the research didn’t straight purpose to evaluate metabolism, we knew from earlier work that salicylate esters might break down into salicylic acid within the pores and skin. We might calculate the entire absorbed dose by measuring each the father or mother compounds and salicylic acid.
CDU: Did the car used (cream vs ethanol/water answer) considerably affect the outcomes?
Dr. Joshi: Sure, significantly for pentyl salicylate. We examined it each in a cream and a 70/30 ethanol/water answer, a standard car in perfume pores and skin absorption research.
The ethanol/water answer notably elevated absorption, underscoring how formulation alternative can dramatically have an effect on dermal supply. It’s a reminder that security assessments ought to take into account real looking, consumer-relevant product codecs.
CDU: What are the broader implications of this research for formulators and regulators?
Dr. Joshi: For formulators, our findings emphasize the significance of contemplating not simply ingredient choice but additionally formulation kind and utilization circumstances when evaluating security. For regulators, this information helps fill crucial gaps in dermal absorption, supporting extra correct systemic publicity estimates.
Finally, this work contributes to accountable innovation by making certain that generally used perfume elements are efficient and protected.
CDU: What’s subsequent on this line of analysis?
Dr. Joshi: We’re persevering with our collaboration with An-eX Analytical Providers to look at extra perfume elements below comparable circumstances. The aim is to develop a sturdy, clear dataset to tell regulatory danger assessments globally.
We additionally hope to discover in vivo–in vitro correlations and refine predictive fashions for pores and skin absorption.
Supply: Toxicology in Vitro, 2025, 106019, doi: 10.1016/j.tiv.2025.106019, “In vitro human pores and skin absorption of ethyl salicylate, pentyl salicylate, and (Z)-3-hexenyl salicylate from topical formulations: Results on permeation and distribution.” Authors: Joshi, Ok. et al.
