A Q&A with RIFM’s Dr. Kaushal Joshi

As regulatory scrutiny round ingredient security intensifies, particularly relating to salicylate publicity and its conversion to salicylic acid, sturdy information on dermal absorption has grow to be 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 examine analyzing the pores and skin absorption of ethyl salicylate, pentyl salicylate, and (Z)-3-hexenyl salicylate—three extensively used perfume components.

CosmeticsDesign spoke with Dr. Kaushal Joshi, Principal Scientist at RIFM, concerning the examine’s findings and what they imply for formulators, security assessors, and regulators navigating evolving requirements in beauty product improvement.

CDU: What prompted this examine, and why give attention to 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 resulting from an SCCS inquiry and discussions from a working group led by Cosmetics Europe.

Moreover, with elevated regulatory give attention to salicylate publicity from beauty and private care merchandise, particularly its conversion to salicylic acid, we noticed a have to generate high-quality, human-relevant information. Ethyl salicylate, pentyl salicylate, and (Z)-3-hexenyl salicylate had been chosen as a result of they’re generally used and characterize completely different structural variations, permitting us to discover how construction impacts pores and skin permeation.

CDU: One of many key takeaways was the influence of occlusion. Are you able to elaborate on that?

Dr. Joshi: Completely. Usually, occlusion is taken into account a extra conservative strategy.

We examined every salicylate below unoccluded and occluded situations, simulating situations 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 situations 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 examine didn’t straight goal to evaluate metabolism, we knew from earlier work that salicylate esters may break down into salicylic acid within the pores and skin. We may calculate the entire absorbed dose by measuring each the dad or mum compounds and salicylic acid.

CDU: Did the automobile used (cream vs ethanol/water answer) considerably affect the outcomes?

Dr. Joshi: Sure, notably for pentyl salicylate. We examined it each in a cream and a 70/30 ethanol/water answer, a standard automobile in perfume pores and skin absorption research.

The ethanol/water answer notably elevated absorption, underscoring how formulation selection can dramatically have an effect on dermal supply. It’s a reminder that security assessments ought to take into account lifelike, consumer-relevant product codecs.

CDU: What are the broader implications of this examine for formulators and regulators?

Dr. Joshi: For formulators, our findings emphasize the significance of contemplating not simply ingredient choice but additionally formulation sort and utilization situations 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 components 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 Companies to look at extra perfume components below comparable situations. The purpose is to develop a sturdy, clear dataset to tell regulatory threat 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, Okay. et al.