Don't Be Rash: What UV Filter Bemotrizinol Means for Children

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Sheilagh Maguiness, MD, a double board-certified pediatric dermatologist at the University of Minnesota and past president of the Society for Pediatric Dermatology, recently joined Don't Be Rash host Andrew Krakowski, MD, to discuss the FDA's approval of bemotrizinol (BEMT). Maguiness also addressed how the new filter may shape sunscreen counseling for pediatric patients.

FDA Approval Ends a 26-Year Gap in New Sunscreen Filters

The FDA approved BEMT this summer, the first new sunscreen filter in the United States in 26 years. Europe and Asia have used the filter, marketed as Parsol Shield and Tinosorb S, for close to 20 years.

"I've been getting inundated with questions from parents: Why are European and Asian sunscreens so much better than what we can get in the United States?" Krakowski said.

Low Absorption Addresses Safety Questions About Chemical Filters

Before BEMT, zinc oxide and titanium dioxide were the only filters on the FDA's list of ingredients generally recognized as safe and effective. Maguiness said a couple of clinical studies found many chemical filters still in use were absorbed through the skin at plasma levels above the FDA's 0.5 ng/mL threshold for waiving additional safety studies.¹˒² Lingering questions about hormonal disruption left many pediatric dermatologists leaning toward mineral filters alone.

"This molecule is very big. It sits on the skin and it really isn't absorbed at all in any significant amount, and that's one of the reasons why the FDA went ahead and approved it all the way down to 6 months and up," Maguiness said.

BEMT also blocks both UVA and UVB. Several chemical filters on the US market cover UVA poorly, so formulators have combined multiple molecules. Krakowski noted a single broad spectrum filter keeps product selection simple.

Photostability and Cosmetic Feel May Improve Adherence

Krakowski added BEMT is more photostable than avobenzone, which requires stabilization with octocrylene. Maguiness explained why degradation matters clinically.

"Some sunscreens paradoxically cause phototoxic reactions; they change configuration when the UV hits them, and then they might become actual irritants and allergens," Maguiness said. "So for those with sensitive skin or those prone to atopic dermatitis, BEMT is going to be very helpful," she added.

The filter is also highly lipophilic, so formulators do not need added oils to incorporate it. Products leave no white cast.

BEMT Will Likely Pair With Mineral Filters in Finished Products

At the 6% concentration on the market, BEMT provides an SPF of about 10 to 15 alone, so it will need partner ingredients. Ultra Violette, an Australian brand, has a product at retail with BEMT, zinc oxide, and octocrylene. Maguiness expects larger US companies to follow once an exclusivity period, which she estimated at 18 months, ends.

"If the sunscreen is just sitting in the bag and it's not on the skin, it is not going to help prevent skin cancer down the road," Maguiness said.

For children 2 and younger, Maguiness noted a thin, developing skin barrier and a higher body surface area to weight ratio increase absorption. BEMT gives clinicians another option for these patients, with the potential for better formulations and greater adherence.

References

1. Matta MK, Zusterzeel R, Pilli NR, et al. Effect of sunscreen application under maximal use conditions on plasma concentration of sunscreen active ingredients: a randomized clinical trial. JAMA. 2019;321(21):2082-2091. doi:10.1001/jama.2019.5586
2. Matta MK, Florian J, Zusterzeel R, et al. Effect of sunscreen application on plasma concentration of sunscreen active ingredients: a randomized clinical trial. JAMA. 2020;323(3):256-267. doi:10.1001/jama.2019.20747