Achieving UVA Protection and Awaiting Regulation Updates at the Sunscreen Symposium

Sep 25, 2009 | Contact Author | By: Katie Schaefer, Cosmetics & Toiletries magazine
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Title: Achieving UVA Protection and Awaiting Regulation Updates at the Sunscreen Symposium
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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.

Next up was Mike Brown (Boots), who observed that “all rating systems are the same, they just use different math at the end.” Brown described adaptations to the Boots star-rating system to take photodegradation into account, in line with EC guidelines. The main factors influencing photodegradation, according to Brown, include the source of the UV exposure, UV filter concentration and film thickness, temperature and the environment. Brown discussed these factors in detail, concluding that test methods should reproduce these parameters and adhere as closely as possible to the “in-use” situation. He found the PPD method to be removed from reality.

Hani Fares (ISP Corp.) then rounded out the mini conference with insights on the FDA’s proposed in vitro UVA methodology. Like previous speakers, Fares noted how the substrate can affect the accuracy of UVA testing. He obtained the highest level of absorbance using quartz plates, adding that greater photodegradation occurred when lower doses were applied to the plates.

A roundtable discussion, moderated by Dennis Lott (Tanning Research Labs Inc.), closed the first day’s session. The expert panel included: Matthew Holman, PhD (FDA); Robert Sayre, PhD (Rapid Precision Testing Labs); Staton; Brown; Nadim Shaath, PhD (Alpha R&D, Ltd.); David Steinberg (Steinberg & Associates); Curt Cole (Johnson & Johnson); Joseph Stanfield (Suncare Research Labs); and Uli Osterwalter (Ciba Corp.).

Steinberg opened with suggestions for changes he would make to the FDA monograph. In reference to the amount of sunscreen applied to a substrate for testing, he noted that 1 mg/cm2 would be a more accurate depiction of actual use by the consumer than 2 mg/cm2. He also suggested removing number and star rating systems, as well the words low, medium, high or very high that indicate levels of UV protection.

Cole commented that products having higher SPF levels protect consumers better against accumulated UV damage and extreme environments. In addition, he defended high level SPFs as also being better for sensitive skin.

Brown remarked that the industry does not need another measurement for amplitude of protection since it already has one—SPF.

Shaath discussed the UV filters used around the world, concluding that there are few efficacious and approved UV filters available in the United States.

The first day closed with a cocktail reception co-sponsored by the FLSCC and DSM Nutritional Products. Guests sipped cocktails and relaxed before the next day’s full sessions.

The second day opened with a breakfast held among the tabletop exhibits, where attendees mingled before proceeding to the symposium.

Steven Q. Wang, MD, director of dermatologic surgery and dermatology at Memorial Sloan-Kettering Cancer Center, served as the session keynote speaker and discussed the consumer’s general knowledge about sun care and related typical behaviors. He noted that consumers associate a base tan with good health and thus concluded that, to reach consumers about the negative effects of sun exposure, the industry must tailor its message to different demographics.

UV filters, specifically titanium dioxide and zinc oxide, were next presented by Patricia Aikens, PhD (BASF Corp.), who noted that although the safety of nano-sized zinc oxide and titanium dioxide has been questioned, both materials show no organ toxicity. She added that longer studies are necessary.

Mendrock-Edinger followed with a discussion on optimizing UV performance. She described factors that can influence the performance of sunscreens, including UV filter compatibilities and emulsifier choices, among others. Mendrock-Edinger recognized ensulizole for its contribution to high SPF levels as well as avobenzone for having the highest absorption power of UVA filters.

Moving the discussion to UVB, William Johncock, PhD, (Symrise) introduced findings in the causes and prevention of UVB-induced photodamage. He described new research suggesting the UVB rays cause a toxic response in the skin via activation of the aryl hydrocarbon receptor (AhR) and then introduced 2-benzylidene-5,6-dimethoxy-3,3-dimethylinden-1-one as an AhR inhibitor.

Hughes Beaulieu (Unipex) followed with a talk on ethnobotanical actives inspired by Native American culture with possible applications in sun care. He described the moisturizing, anti-inflammatory, anti-free radical and photoprotective effects of Sambucus nigra flower extract.

Photoprotective raw materials were also discussed by Lionel Resnick, MD, (Florida Atlantic University), who introduced the sun protective effects of sulindac (Clinoril), an FDA-approved NSAID. According to Resnick, sulindac, previously used for its anti-tumor activity, has also been found to act as a UVB inhibitor. He found combining the material with hydrogen peroxide also reduced erythema in skin.

Yun Shao, PhD, of Kobo Products continued the session with non-nano inorganic UV filters, noting recent concerns over the safety of nanomaterials. Ultrafine titanium dioxide, according to Shao, scatters more visible light and is transparent, whereas non-nano titanium dioxide is opaque. He concluded that an official test method for nanoparticles has yet to be defined.

An improved in vitro measurement for sunscreens was then reviewed by Stanfield, who noted that a molded PMMA plate is perhaps the most critical part of the test, although other important aspects include the application and UV irradiation source.

Karen E. Burke, MD, PhD, concluded the morning session with the presenation, “Sunscreens May Not Be Enough.” She stressed the importance of vitamins in maintaining and protecting skin. According to Burke, UV depletes vitamin C and E from the skin. However, daily oral administration can decrease the incidence of sunburn and provide antiaging benefits.

After a break for lunch, attendees milled about the poster session to view the latest sun care research before retiring to rest up for the third day.

Sunscreens also were not enough for Howard Epstein, PhD, (EMD), who opened the third day’s sessions with an introduction to antioxidants that can benefit sunscreen formulations, including tiliroside and isoquercetin.

Following Epstein, Chuck Jones (Dow Personal Care) presented on optimizing the efficiency of inorganic sunscreens. According to Jones, a conundrum exists between formulating to achieve a high SPF and maintaning good aesthetics. He introduced methylcellulose as a sunscreen booster, noting it can double the SPF of sun care products.

Osterwalder then correlated the radical sun protection factor of sunscreens with their UVA protection factor. According to Osterwalder, “Good radical protection means good UV protection.”

Finally Mike Davies (Essential Ingredients) rounded out the first lineup of morning presentations with a discussion of pine rosin from pine stumps. According to Davies, abietic acid derived from rosin can protect the skin from UV damage.

After the morning break, Alain Thibodeau, PhD (B&T Technologies) continued the talks with a discussion on sorbitan olivate in silicone systems to enhance UV protection. He described a naturally derived sorbitan olivate-based technology developed to provide UV protection and provide water-resistancy to formulations.

Oliver Springer, PhD, (Evonik Goldschmidt GmbH) then touched upon the role of emollients in sunscreen formulations. According to Springer, it is important for emollients in sun care formulations to be multifunctional.

The final podium presentation was given by Niven R. Narain, MD, who discussed a novel anti-cancer agent. Narain reviewed Cytotech API 31510 in skin cancer therapy for modulating apoptotic/angiogenic cross-talk mechanisms with an expected safety profile supportive to normal skin.

Robert Lochead from the University of Southern Mississippi closed the symposium portion of the event, which flowed into the exhibition hall for lunch.

After three days covering the broad spectrum of sun care, attendees gathered at the symposium’s gala dinner, co-sponsored by DSM Nutritional Products and the FLSCC. The dinner featured sun care-inspired drinks, international delicacies and a variety of mini desserts to put the perfect cap on the event.

The Florida Sunscreen Symposium, a biennial event, will welcome back attendees in 2011 to hopefully, by then, address updates to the FDA monograph, among other key sun issues.

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2009 FLSCC Sunscreen Symposium

The Florida Chapter of the Society of Cosmetic Chemists held its 12th Sunscreen Symposium on Sept. 10-12, 2009.

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