A new revised monograph for sunscreen guidelines from the FDA is in the pipeline and awaiting approval. According to one expert, the proposals made were necessary to enable physicians and consumers to better assess the ability of sunscreen products to protect across the UVB and UVA ranges.
There are several components to this monograph. Among them are a list of the active sunscreen ingredients - that is, the ultraviolet filters that are permitted for use in the United States, in terms of what chemicals are used, at what maximum concentration they can be used, or what kinds of combinations of sun-protective chemicals can or cannot be used.
FDA guidelines must be followed by manufacturers of any type of sunscreen product marketed in the United States. The revised monograph would also specifically outline how manufacturers can test for the SPF (sun protection factor) as well as the ultraviolet A (UVA) protection factors offered by sunscreens.
According to Dr. Lim, the FDA proposes to increase and cap the SPF for UVB at 50+, because many dermatologists believed the proposal in the 1999 version of the FDA sunscreen monograph, which capped the SPF at 30+, was inadequate to provide the proper protection.
Sun protection factor products are tested in vitro at a concentration of 2 mg/cm2 . In actual use, individuals do not use that concentration when applying sunscreens.
Usually, an individual will use 0.5 to 0.8 mg/cm2 , and because of this, automatically, the in-use SPF is lower compared to the labeled SPF. For example, for a product with an SPF of 30, the in-use SPF could be less than 10.
"This is the reason why the American Academy of Dermatology proposed that the cap should be higher. That way, in reality, if a patient applies less of a product, there would still be enough sunscreen on the skin to produce an adequate SPF," Dr. Lim tells Dermatology Times.
The UVA-SPF using the persistent pigment darkening (PPD) method is one of the methods that has been used for many years, and is probably the in vivo method most widely used to assess the UVA protection of sunscreen.
Essentially, this method is very similar to the determination of the SPF, except that persistent pigment darkening is used as the endpoint of evaluation, following exposure to UVA.
Other new developments with sunscreens include the FDA approval of products containing Mexoryl SX (ecamsule), a photostable short UVA filter, and the availability of products with photostabilized long UVA filter, avobenzone (butyl methoxydibenzoylmethane).
Dr. Lim highly recommends a product that contains one or both ingredients in the sunscreen, providing a "broad-spectrum" protection. A listing of Mexoryl products currently available in the United States is shown in Table 1.
"I do recommend broad-spectrum UVB-UVA sunscreens for my patients.
"In the U.S., unfortunately, until the new FDA UVA protection guidelines are implemented, the only way for the average consumer to know which broad-spectrum sunscreen to use is to look at the 'broad spectrum' label on the package, and to read the active ingredients of the product," Dr. Lim says.
Disclosures: Dr. Lim is a consultant for, or has received honoraria from, La Roche-Posay/L'Oréal, Orfagen and Dow Pharmaceutical Sciences, and has been an investigator for Johnson & Johnson.