FLSCC Incites Regulation Debate on Sunscreens

By: Katie Anderson (Schaefer), Cosmetics & Toiletries magazine

Posted: September 28, 2011

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Thomas Rudolph, PhD, senior scientist at Merck KGaA, provided new insights into the photochemistry of avobenzone. He noted that UV filters, whether photostable or not, can be photoreactive. He added that photostability can be achieved with triplet quenchers, antioxidants and regenerators.

Rounding out the morning presentations was John Staton, who discussed zinc oxide with new test protocols. Staton conducted the ISO 24443 on zinc oxide and found inconsistencies. The team noticed a change when zinc oxide was exposed to sunlight. They found this to be agglomerate formation. This can be prevented with surface treatment. He added that the thinner film mandated by the FDA makes it difficult to achieve the critical wavelength.

The afternoon began with Robert Coots, PhD, who discussed non- ethoxylated emulsifiers for sunscreens. He noted that 1,4 dioxane is a byproduct of ethoxylated emulsifiers. He introduced alkyl polyglucosides as non- ethoxylated emulsifiers.

Erica Babson then went on to talk about enzymes to modulate DNA repair. She discussed T4 endonuclease, an enzyme that induces single-stranded breaks in UV-irradiated DNA. She also mentioned histone deacetylases, which remove acetyl groups from certain histone amino acids. However, her focus was on sirtuins, which regulate important cell pathways and increase the expression of SIR genes. Her company, Active Concepts, developed a fermented may apple that can reduce DNA damage and increase UV protection.

The last presentation of the day was by Jürgen Volhardt on critical factors that affect high performance sunscreens. He noted that high performance in sunscreens can be achieved with sufficient UVA performance. This UVA performance is due to a significant level of UVA filters with good coverage of the spectral region and good stabilization of avobenzone. High performance can also be achieved with beneficial formulation effects, such as cetyl phosphate, and additional SPF-boosting with titanium dioxide to reach the target SPF.