Achieving UVA Protection and Awaiting Regulation Updates at the Sunscreen Symposium

By: Katie Schaefer, Cosmetics & Toiletries magazine

Posted: September 25, 2009

Although summer was drawing to a close, sun protection was still the hot issue for the 350+ attendees of the Florida chapter of the Society of Cosmetic Chemists’ (FLSCC) 12th Sunscreen Symposium. The event theme, “Perpetuating Beauty Through Protection,” was at the forefront of all three days of lectures.

Craig Bonda (HallStar Personal Care) first provided some context for the symposium by illuminating—and in some cases, puzzling—attendees with a half-day course on the intricacies of sunscreen photostability. He covered various UVA evaluation methods, including substrates such as PMMA, Vitro-skin, transpore tape and roughened quarts, and noted that, “in vivo SPF and PFA tests are UVA challenges.” Bonda also discussed regional SPF labeling requirements and presented “Dexter,” a visual tool developed to explain how materials achieve and dissipate excited states.

Bonda continued with a description of the available sunscreen materials, adding that some, such as 4-methylbenzamine camphor, are pending and may become available in the United States soon. Describing challenges with existing UVA absorbers, Bonda commented, “the behavior of sunscreen products is not predictable from its individual ingredients,” and gave the example of octinoxate reacting with avobenzone to cause photo-decay. He closed his course by reminding attendees to: consider patent infringement, make good emulsions, take the photostability of UV filters into account, and to avoid metal ions. “Photochemistry can have a profound effect on your formulation,” said Bonda. “It can either work for you or against you.”

After a quick lunch break, the afternoon featured a UVA mini conference, moderated by Christine Mendrock-Edinger (DSM). The first presenter, John Staton (Dermatest Pty., Ltd.), discussed validating UVA testing in vitro. Staton noted that the ISO ring study—which addresses technician control over pre-irradiation devices, higher sample doses (1.3 mg/cm²), rougher plates at ~6 μm, and a xenon-only exposure arc—is expected to be completed soon.

The UVA discussion continued with Julian Hewitt (Croda), who delved into formulation strategies to meet differing global UVA requirements. He commented that while SPF tests are similar worldwide, UVA testing differs greatly. Hewitt, among others, noted his anticipation of the new monograph from the US Food and Drug Administration (FDA). “I feel sorry for sun care formulators in the United States,” said Hewitt, who added there are few usable UV filters in the United States.