FLSCC Incites Regulation Debate on Sunscreens

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

Posted: September 28, 2011

The Florida chapter of the Society of Cosmetic Chemists (FLSCC) held its 2011 Sunscreen Symposium on Sept. 15-17, 2011. The event’s theme, “The UVB/UVA Balancing Act: Choices and Change,” was supported not only in the presentations but was also reinforced through attendee questions and reactions to recent sunscreen regulation.

The first morning began with Reynold Tan, PhD, an interdisciplinary scientist in the US Food and Drug Administration’s (FDA) Office of Nonprescription Products, who reviewed the proposed dosage forms rule and the proposed SPF50 cap. Tan started with the SPF cap, noting that the FDA is trying to determine if higher SPF products provide additional benefit to the consumer. Tan added that while SPFs as high as 80 can be accurately tested, there is incomplete data showing their additional protection for the consumer, as SPF50 already protects against 98% of UV radiation that causes sunburn. Also, the additional actives and ingredients in high SPFs may cause irritation, according to Tan. Regarding dosage forms, the FDA is specifically interested in more information on spray sunscreens. Tan noted that the FDA is looking for more data on how consumers apply spray sunscreens and if they apply enough to prevent sunburn. Tan encouraged people to submit safety and efficacy data regarding spray sunscreens.

Chuck Jones, PhD, a scientist with Dow Chemical Company, followed with a presentation on formulating acceptable inorganic sunscreens. He noted that consumers, although interested in inorganic sunscreens, often notice their whiteness. He referenced studies that projected inorganic UV filters to grow faster than organic UV filters and titanium dioxide to grow faster than zinc oxide. Contrary to some previous studies, he found that smaller particle sizes do not necessarily reduce whiteness. He concluded that titanium dioxide offers higher SPF values with minimum whiteness, unless one has a low whiteness zinc oxide. He added that there are strategies to reduce whiteness and increase SPF. These include the addition of an SPF booster such as styrene\acrylates copolymer, the addition of a dispersing agent such as methylcellulose or galactorabinan to provide a better distribution of inorganic and higher SPF or the addition of an organic ‘stabilizer/emollient’ such as butyloctyl salicylate.

Anna Langerveld, PhD, president and CEO of Genemarkers, and Nava Dayan, PhD, R&D and safety assessment director at Lipo Chemicals Inc., then jointly presented on their use of high throughput gene expression profiling to understand how high energy visible light (HEV) may affect skin. They noted that HEV penetrates deeper into the dermis then UVA and UVB wavelengths, adding that HEV can interact with DNA to produce ROS and thymine dimers. Through microarray and qPCR testing, the two found that the somatostatin (SST) gene was upregulated in all three time exposures (6 hr, 12 hr and 24 hr). While SST can be used to treat psoriasis, rosacea and possibly cancer due to its inhibition of the cell cycle and cell proliferation, it increases oxidative stress and cell senescence or aging.

Free radicals were also discussed by Bernd Herzog, who spoke to attendees about free radical protection in sunscreens. His team measured radicals using two metrics, integrated sun protection factor (i-SPF) and radical status factor (RSF). He found that both show good correlations to calculated RSFsim and UVA-PFsim data. He also found that while the i-SPF slopes of the correlations are close in unity, the RSF values appear to be higher than expected. He noted that RSF may be a better measure of free radical protection, but that more studies are needed to prove this.