Guiseppe Valacchi, University of Ferrara, reviewed the range of stressors that the epidermis is subjected to on a daily basis including ultraviolet radiation, solar radiation, ozone, tobacco smoke, nitrogen dioxide and particulates. He reviewed each in detail noting, for example, that ozone induces heat shock protein and matrix metalloproteinases.
Valacchi concluded that there is close relationship between environmental stressors, aging, oxidative stress and inflammation.
Calling Brisbane, “the skin cancer capital of the world,” Michael S. Roberts, University of South Australia, was uniquely qualified to review the role of sun photodamage in skin aging and compromised immune responses.
Roberts reviewed the immune responses in photodamaged skin, pointing out that UV radiation suppresses immunity by inhibiting effector and memory T cells. UVR also causes dendritic cells and macrophages to secrete immune-suppressive IL-12p40 homodimers. However, the immune-modulating cytokine and endogenous alarmin interleukin-33 is upregulated in skin exposed to inflammatory UVB radiation.
“The use of UV physical and organic filters to prevent UVR-induced damage in the skin is essential,” Roberts explained.
He noted that UVR-induced damage in human skin plays a major role in skin photoaging as it increases collagenase and other extracellular matrix-targeting proteinases. It also reduces collagen, free fatty acids and triglycerides within the dermis. Furthermore, UVR radiation in the skin leads to photo-immunosuppression.
In recent years, researchers and physicians have blamed inflammation for a host of maladies. Bryan B. Fuller, founder of DermaMedics, reviewed UVR-induced inflammation, its impact on aging and how it can be treated with natural topicals. He called inflammation the No. 1 problem in dermatology, and said it is responsible for skin cancer, rosacea, acne, psoriasis, eczema/dermatitis, radiation burns, laser burns and hyperpigmentation. Three inflammatory mediators, PGE-2, TNF-a and IL-1, all play an important role in these skin disorders. In fact, the combination of retinol and UV actually induces the production of PGE-2, according to the speaker.
“For any anti-aging product to be effective, it must target inflammation,” Fuller insisted, and he suggested that formulators should incorporate spin trap nitrones in their anti-aging formulas. In his research, the use of phenyl-n-tert butyl nitrone blocked free radicals and reversed oxidation damage; prevented peroxidation of membrane fatty acids, delayed senescence in fibroblasts, prevented glycation, reduced retinopathy, prevented scarring in burn victims, reduced cardiovascular toxicity of chemotherapy, prevented ROS-induced carcinogenesis, extended the lifespan in animal models and improved cognitive function.
But Fuller warned the audience that anti-aging compounds must block collagenase yet stimulate collagen expression in aging fibroblasts. He also called for the development of non-tyrosinase inhibitors to target UVR-induced hyperpigmentation.
Chemists may develop an effective formula, but how can they measure that efficacy? Terrence J. Piva of RMIT University explained the development and use of the Immune Balance Rating (IBR) in formulating sunscreen products. He described it as a complementary test to both SPF and UVA testing and said it is gaining industry acceptance.
Piva’s team has proposed an IBR rating comprising five criteria: Immunostimulation, immunosuppression, phototoxicity, protection against UV damage and protection against UV immunosuppression. In the IBR system, these five indicators are aggregated, with the worst rating determining the overall rating for the test material.
According to Piva, IBR provides a cost-effective screening protocol enabling identification of ingredients that interact with immunity, which can be exploited or avoided. IBR also enables chemists to avoid unnecessary screening of unsuitable ingredients, mixtures and formulations in trials. But while IBR can reduce the need to test for allergic reaction and skin sensitivity in human trials, it will not replace them. IBR also minimizes formulation costs for specific preparation by defining acceptable ingredient levels and provides evidence-based information for formulation decisions, Piva said.
Where’s the Monograph?
That’s all well and good, but how can formulators create products using a limited palette of active ingredients?
The US FDA first asked the sun care industry for sunscreen data in 1972. Forty years later, the world is still waiting for the Final Sunscreen Monograph. Curtis Cole, VP-R&D, Johnson & Johnson, reviewed the history of the Monograph, where it stands now and the impact the delay is having on regulation and, ultimately, innovation. For example, the FDA has yet to finalize ingredients and their combinations; nor has it finalized the SPF 50 cap or spray form dosage. That said, manufacturers are allowed to make anti-aging and anti-skin cancer claims if products have SPF 15 or higher and provide broad-spectrum protection.
The ruling also allows the use of multiport solar simulators for SPF testing, reduces test panel size from 20 to 10 for SPF testing, and relies on critical wavelength test methods for “broad spectrum” claims and not the UVA1/UV ratio test.
Unfortunately, the test method for critical wavelength is not harmonized with COLIPA or ISO UVA tests, Cole noted. The good news is further tempered by the fact that formulators need more ingredients.
“We have a limited tool chest,” observed Cole. “We only have 16 approved actives in the Monograph and industry only uses six of them!”
He predicted that innovation would be further comprised in the coming years if legislators approve more Prop. 65 regulations. While regulators mull new measures and FDA waits, consumers are unable to use several effective sunscreen actives that are already approved outside the US.
Cole called for regulatory innovation based on new regulatory pathways that facilitate access to consumer benefits; dialogue between industry and regulatory agencies to expedite rulemaking; recognition of differences in product usage; i.e., cosmetic v. recreational; common sense approaches to promote realistic product use labeling and a regulatory pathway for new product forms.
With so many hurdles to overcome, how can formulators still churn out innovative sun care products?
Helene Hine of Croda urged attendees to exploit the latest advances in titanium dioxide technology, noting that tailored dispersions meet differing regulatory requirements and aqueous based titanium dioxide dispersions offer formulation flexibility.
Seki Cosmeceuticals’ Wen Schroeder brought the symposium to a close with a look at the latest news from Australia where a new sunscreen standard (AS/NZS 2604:2012) is getting implemented. It raises the maximum SPF to 50+ without changing water-resistance requirements. But at the same time, the ruling eliminates terms such as “sunblock,” “waterproof” and “sweatproof.”
But even in a country such as Australia, where consumers have access to the most effective sunscreen formulas and use them liberally, the sun care industry faces scrutiny.
“The coral reefs are getting bleached out,” noted Schroder. “How do we fix that?”
Sounds like the topic for another NYSCC symposium. Stay tuned.