MULTICENTER EVALUATION OF SUNSCREEN UVA PROTECTIVENESS WITH THE PROTECTION FACTOR TEST METHOD

Background: Currently there is no consensus on a test method to determine the protectiveness of sunscreens in the UVA region alone. Objective: The protection factor in UVA (PFA) test method was evaluated to determine its ability to detect dose-response, specificity for UVA protection only, and repeatability between laboratories, and to detect whether the protection factors depended on the skin response observed (erythema or tanning). Methods: Sunscreens containing 0%, 2%, or 5% oxybenzone, or 7% octyl dimethyl para-aminobenzoic acid were tested by the PFA protocol in five laboratories. Results: The test method demonstrated ability to distinguish differences between the protection in the oxybenzone formulations but not between the placebo (0%) and the 7% octyl dimethyl para-aminobenzoic acid formula. The protection factors were independent of the type of skin response. Conclusion: These data support the utility and validity of the PFA method for determining the UVA protection provided by sunscreen products.