But since she did neglect her looking glass
And threw her sun-expelling mask away,
The air hath starved the roses in her cheeks,
And pinched the lily-tincture of her face,
That now she is become as black as I.
— William Shakespeare, The Two Gentlemen of Verona, IV, 4, 151–153
Even in Elizabethan times, women knew that sun exposure was bad for the skin. Commoners couldn’t afford or be bothered with sun protection, but noble ladies usually wore a mask—Shakespeare’s “sun-expelling mask”—typically made of black silk. And however much science has advanced, blocking the sun is still the first rule for maintaining youthful-looking skin. While this Elizabethan lady was clearly aware of the visible aging effects of excess sun exposure, people also are now equally concerned with the prevention of cancer. In fact, sun protection may be the single most important benefit the beauty industry can offer consumers.
Every other year, the Florida chapter of the Society of Cosmetic Chemists holds a well-regarded sunscreen seminar, but as 2012 was an off year for the event, in October 2012 the New York Society of Cosmetic Chemists (NYSCC) hosted a program titled “Sun Exposure: Implications and Protection of Skin.”1 Sun protection has gone far beyond SPF numbers, and this meeting demonstrated how complex and extensive the subject has become. The brave new world of sun protection features environmental stressors, inflammatory pathways and immune responses, among a myriad of arcane topics.
The Science—and Regulation—of Sun Care
We have been looking beyond SPF for years. UV causes DNA damage, and while the body’s cells have natural repair mechanisms, when the damage is too extensive (as in sunburned skin), the mechanism is overwhelmed and the cellular order is given to shed the skin. Antioxidants are used to stop damaging cascade reactions that continue even after the sun exposure stops, and solutions ranging from aloe to DNA repair enzymes have been used in after-sun protection products to minimize and remedy the effects of excess sun exposure.
Sunscreens were already difficult to formulate in the U.S., with a limited palette of UV absorbers and a long process to get new actives on the list. And a final sunscreen monograph from the FDA has taken an unusually long time to be unveiled, even by government regulatory standards. Changing rules on allowed SPF claims, water resistance, broad spectrum protection and testing protocols have created fundamental challenges for beauty product developers, and all these issues were merely the jumping off point for speakers at the NYSCC program.
Everything regarding sunscreens in the U.S. starts with the FDA monograph. Curtis Cole, PhD, VP of R&D skin care innovation platforms at J&J Consumer Products Skin Care, described the timeline of the monograph process, explaining that the story starts with the request for data in 1972, goes on to the notice of a proposed rule in 1978, sees the “final” monograph in 1999, observes the stay of the enactment in 2001, has a proposed amendment to the monograph in 2007, continues on to a final rule on labeling and efficacy testing in 2011, and, currently, is in the waiting period for the final Final Monograph. A process that started in 1972 and is yet to be resolved speaks loudly for itself.
Even when the monograph is final, there will still not be harmonization with other regions on important issues of claims, allowed actives, testing and labeling. And even with the proven health benefits of sun protection, there remain critics of the products—with criticism especially focused nanomaterials, suspected endocrine disruptors and the irrational fear of chemicals in general.
Sun Care Innovations
One possible global solution, explained by Helene Hine of Croda, utilizes customized titanium dioxide (TiO2). Titanium dioxide is a physical blocker, like the Elizabethan mask, often used as a premixed dispersion. The particle size and distribution, as well as the carrier system, can be fine-tuned to create different properties—different from titanium dioxide in the old days, which created the classic white paste on a lifeguard’s nose. The large particles reflected light very effectively, but to eliminate the whitening effect the particle size had to be reduced to a quarter of the wavelength of light.
But now another factor enters. The new criteria require blocking at 370 nm, and this requirement is just beginning to nudge the whitening size of the titanium dioxide. To create the ideal size and ensure tightly controlled size distribution, dispersions from companies specializing in this area are the best solution.
An interesting approach to advanced formulating concerns with titanium dioxide was presented by Terrence Piva, PhD, of RMIT University in Australia. (A version of his presentation, given at another conference, can be found online.2) During the past decade, attempts have been made to go beyond SPF to measure the immune protection factor. It is assumed that sunscreens should protect against UV-induced immunosuppression, with a measure of protection that can be compared to SPF. (A summary of this work through 2005 was published by Foutanier.3)
An immune balance rating (IBR) was developed in Australia through a combined effort of Monash University, RMIT University in Melbourne and Baxter Laboratories. Their research resulted in a method for determining the potential for an immune system response to topical sun care ingredients, components and formulations, including the potential for hypoallergenicity.
The tests were conducted on human skin cells and immune cells for their likelihood of eliciting an immune system response. Alterations in biomarkers were assessed and measured using a specific quantitative assay, and the dose response profile of each test compound can be compared to known reference material. The rating comprises five “product indicators”—immunostimulation, immunosuppression, phototoxicity, protection against UV damage, and protection against UV immunosupression—to indicate performance.
Immune balance rating involves many steps and differs for each indicator. As an example of the materials used, testing immunostimulation and immunosuppresion uses treated or derivatives of THP-1 human monocyte cells. Established 30 years ago, THP-1 cells are widely used in cell culture across the world. They have the ability to secrete mediators such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1 alpha (IL-1 alpha) and interleukin-1 beta (IL-1 beta) into the media. These are materials that should be familiar to anyone studying immune response, and, in this case, can predict hyperallergenicity among other properties.
A Place in Sun Care
Why get involved with all this? Because one thing sunscreens can do is prevent melanomas, including most critically malignant melanomas. To do it optimally, sun care product developers and formulators must think past SPF to all the other damaging cascades triggered by UV radiation. The sunscreens of the future will offer much greater lifetime protection by taking advantage of the deeper insight we are now gaining in the underlying causes of the damage.
The tool box of cosmetic science now contains an ever-increasing load of biological pathways, and thus, the formulation of the sunscreen of the future goes far beyond SPF and water resistance, extending to the fundamental causes and prevention of malignant melanoma. The total formulation, not just the actives, must be considered far more carefully. It is challenging, more so than just extending protection from UVB to UVA. But these challenges are what moves the beauty industry forward and make it so exciting.
- NYSCC International Symposium, Sun Exposure: Implications and Protection of Skin, Oct 12, 2012
- www.baxterlaboratories.com/wp-content/uploads/2012/06/Immune-Balance-Rating_-Sun-Protection-Conference-London-2011.pdf (Accessed Dec 11, 2012)
- A Fourtanier, et al., Measurement of sunscreen immune protection factors in humans: a consensus paper, J Invest Dermatol, Sep 125(3), 403–409 (2005)
Steve Herman is president of Diffusion LLC, a consulting company specializing in regulatory issues, intellectual property, and technology development and transfer. He is a principal in PJS Partners, offering formulation, marketing and technology solutions for the personal care and fragrance industry. He is the New York Society of Cosmetic Chemist’s 2013 Chapter Chairman and an adjunct professor in the Fairleigh Dickinson University Masters in Cosmetic Science program. He is also a Fellow in the Society of Cosmetic Chemists.