ABSTRACT
Introduction 808
Background on the Requirements for UV-A/UV-B Proportionality 809 Protection Minimums for Proportional UV-A/UV-B Protection 811 Beyond the Minimum Balance Requirements: Extra UV-A Protection 813
Identification and Communication of Two Distinct Levels of
UV-A Protection 813
The Need to Measure Both Breadth and Quantity of Protection 815
Testing Formulations to Evaluate the Reproducibility of the PFA and
Persistent Pigment Darkening UV-A Test Methods, with Additional
Assessment of Broadness 816
Results 817
Discussion 818
Conclusions and Recommendations 823
References 824
INTRODUCTION
In 1996, industry submitted to Food and Drug Administration (FDA) for
consideration an in vitro UV-A test method called Critical Wavelength (1).
That method measured the broadness of the protection provided by a sunscreen
product, but did not address either the magnitude of protection or the issue of
the appropriate proportionality of UV-A to UV-B protection. The importance
of assessing the quantity of UV-A protection provided by sunscreen products
was highlighted by the FDA in correspondence relating to the approval of the
combination of avobenzone with certain other active ingredients (2,3). In that
correspondence, the Agency asked for additional clinical UV-A protection data
beyond Critical Wavelength to support the UV-A efficacy of those ingredient
combinations. The data that the Agency requested was to be based on the in
vivo Protection Factor A (PFA) test method (4).
