Photostability spectral

Measuring the photo-stability of sunscreen products is essential to ensure constant UV protection against the harmful effects of the sun’s rays. This property determines the product’s ability to maintain its efficacy by effectively filtering UVA and UVB rays over time, despite exposure to the sun. Adequate photo-stability is therefore crucial to preventing sunburn, premature skin ageing, and reducing the risk of long-term skin damage.

From a formulation point of view, assessing photo-stability helps developers to optimize the selection of UV filters and stabilizers, thus fostering innovation and improvement in sunscreens. Indeed, bhile each UV filter has its own distinct photochemical properties, these can be influenced by the stereochemical composition of its environment, thus modifying its reaction to exposure. As a result, it is possible to observe significant variations in the photodegradation of different formulations, even when they incorporate the same UV filters. Fortunately, a balanced formulation can minimize or even prevent photoinstability..

Optimizing the stability of sunscreens therefore requires in-depth, specific analysis for each new formula developed.

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days for an in vitro study with a final report

solar studies carried out

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compliance with solar standards

Development

As part of your product development or to identify a candidate ingredient, we offer screening tests that enable you to assess UVB and UVA protection with ease.

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In Vitro Photostability - Standard approach

The present protocol consists in evaluating the evolution of the protection level of sunscreen after exposure to UV at a specified UV dose. This method, based on spectrophotometric measurement, determines the overall physical and chemical photostability of a sunscreen product.

(ref. HePHOTOSTAB-1)

CLAIM

We can assess the sun protection of your products in full compliance with official methods, or claim the properties of your products through exclusive tests developed by WENEOS.

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In Vitro Photostability - Dynamic approach

A paradox of sunscreen products is that to protect against UV rays, they need to be exposed to them, which leads to their photodegradation and, consequently, a gradual loss of efficacy. This dynamic method measures photo-stability on the basis of the residual efficiencies of the UVA + B parts in a formula. Using a reproducible substrate, automated spreading and different doses of UV exposure, samples could also be sorted in order of stability, potentially providing new labeling claims.

Published method: Photostability Test for Additional Sunscreen Claims, Part I: Protocol Setup, Part II: Calculations and Results, Part III: New Claim - S. Miksa, D. Lutz and C. Guy, C&T, November 2015

(ref. HePHOTOSTAB-2)

Quality control

To optimize your suncare products or check their quality, we offer you exclusive tests developed by WENEOS.

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Comparison of in vitro signal absorbance measurements with resistance (batch, aging, etc.)

The statistical comparison method makes it possible to compare two sun protection products in terms of ageing, batch, benchmark, etc. When checking the absorbance spectrum between a reference and a test product using an in vitro method, two important rules must be observed. First of all, compare the two products at the same time and under the same conditions, to limit measurement variability. Secondly, a three-step verification based on absorbance values, including comparison of curve shape, variability and intensity.

In this method, a specific step for comparing the resistance of the two products can be added, such as photo-stability, water resistance, rub resistance, etc.

(ref. HeCOMP-2)

Published method : *In vitro comparison - A new accessible and reliable statistical method to compare the global UV protection properties of cosmetics - Lutz and S. Miksa, H&PC Sun Care, July/August 2013 | *Sunscreen products: Some practical applications for a new comparison test method to help Development and ensure Quality Controls - D. Lutz, S. Miksa and C. Guy, H&PC Today, November/December 2014

Discover the analyses additionalfor all-round sun protection

UV protection

  • SPF – UVB
  • UVAPF – UVA
  • UVA:UVB ratio
  • Photostability
  • Absorbance spectrum
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Beyond UV

  • Ultra-Long UVA
  • Blue Light
  • Visible
  • Infrared
  • Full Spectrum
  • UVC
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Resistance

  • Water resistance
  • Sweat resistance
  • Sand resistance
  • Rub resistance
  • Wet Skin Application
  • Extreme conditions
  • Persistence | Long-lasting
  • Immediate protection
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