Vienna, Austria — While it is increasingly clear that ultraviolet A radiation (UVA) defense is essential for immune protection, in the United States, unlike many other parts of the world, there is a lack of uniform standards for the assessment of UVA protectiveness of sunscreen.
Vienna, Austria - While it is increasingly clear that ultraviolet A radiation (UVA) defense is essential for immune protection, in the United States, unlike many other parts of the world, there is a lack of uniform standards for the assessment of UVA protectiveness of sunscreen.
"Sunscreens with clearly defined broad spectrum protection is needed (in the United States)," said Henry W. Lim, M.D., at the 10th World Congress on Cancers of the Skin, here. "We know that sun protection factor (SPF) is a reflection of the protection against the erythemogenic effect of UVB (rays). While there are several methods to assess the protectiveness against UVA, these have not yet been applied in the United States."
UVA filters approved by the U.S. Food and Drug Administration (FDA), including avobenzone (Parsol 1789) and benzophenones, and inorganic (physical) filters, namely, zinc oxide and titanium dioxide, are the primary sunscreen actives used to protect against skin damaging UVA. However, there are several filters with UVA protection superior to the above available in other parts of the world, including Canada, European Union, Mexico and Japan. Some of these are currently undergoing the FDA approval process; as such, they are not yet available in the United States.
Additional superb UVA filters include Tinosorb M and Tinosorb S, both manufactured by Ciba Specialty chemicals. Both are approved in Europe, and Tinosorb M is also approved in Australia. Both are photostable and have strong absorption in the UVB and UVA range.
"Mexoryl and Tinosorb are significantly better than what we have now in the States for two reasons: one, both have significantly better absorption in the UVA range; and two, from the data we have now, both are photostable - they do not degrade following exposure to light like many of the filters used currently," says Dr. Lim, chairman and C.S. Livingood chair, department of dermatology, Henry Ford Hospital, Detroit. "Recent studies show that both types of Mexoryl are better than all (UVA) filters in the U.S. in prevention of photo-induced conditions."
In several studies, the presence of Mexoryl SX and Mexoryl XL rendered sunscreen products to be more efficient in preventing the induction of lesions in patients with photosensitive lupus erythematosus and in those with polymorphous light eruption, as compared to sunscreens containing avobenzone and Ti02, as the UVA filters (Stege, H, et al, Photodermatology Photoimmunology & Photomedicine, Volume 16 Issue 6 , December 2000, and Moyal, D, et al, J European Acad of Dermatology and Venereology, Sept 1999, s 317).
"What's important is that we recognize UVA plays a significant role in immune suppression, and that there are excellent UVA filters available that would benefit our patients in the United States," Dr. Lim says. "Mexoryl SX, Tinosorb M and Tinosorb S are at various stages of the FDA-approval process. It is our hope that this process will move forward in a timely manner."