J. Cosmet. Sci., 64, 297–307 ( July/August 2013) 297 Disparate SPF testing methodologies generate similar SPFs KATHERINE GARZARELLA and MICHAEL CASWELL, Consumer Product Testing Company, Inc., Fairfi eld, NJ. Accepted for publication January 14, 2013. Synopsis Regulatory agencies throughout the world have developed exclusive methodologies for assessing and classify- ing sunscreen product effi cacy in their respective markets. Three prevalent methods, the Food and Drug Administration-Final Monograph (FDA-FM) method, the Australia/New Zealand (Aus/NZ) method, and the COLIPA International (International) method, contain procedural and statistical dissimilarities with undefi ned signifi cance. The objective of our clinical trials was to evaluate the infl uence of these disparities on sun protection factor (SPF) values. Our clinical trials evaluated the SPF of 59 test materials, using two or all three of the aforementioned methods in simultaneous trials, providing two or three SPF values for each for- mulation. A total of 135 trials were conducted. The consequent mean SPF values generated per trial were used to compare methods in a correlation and variance analysis. The correlation coeffi cients for each method pair, International vs. FDA-FM, Aus/NZ vs. FDA-FM, and International vs. Aus/NZ, were each ≥0.94. The difference in least square mean SPF for each method pair was 0.12, 0.62, and 0.81, respectively. Our juxta- position of the mean SPFs produced by these methods clearly illustrate that any disparities between average SPF values produced by these methods are not clinically or statistically signifi cant and that using one method should be suffi cient for SPF labeling in all three respective markets. INTRODUCTION The universal demand for reliable sunscreen products that protect users from the short- term and long-term consequences of ultraviolet (UV) radiation has led to the develop- ment of regional standards in sun protection factor (SPF) evaluation test methodologies. Sunscreen products sold in American markets must comply with the current Food and Drug Administration (FDA) Over-the-Counter (OTC) monograph (1–3), whereas identi- cal formulations sold in Australia and New Zealand are generally evaluated with the method developed by the Joint Australia and New Zealand Standards Committee (4). Japan, Korea, and other Asian countries frequently evaluate the effi cacy of sunscreen products with the COLIPA International method (5,6). Since these clinical trials were completed, the FDA has published the Labeling and Effectiveness Testing: Sunscreen Drug Products for OTC Human Use or Final Rule (3) on June 17, 2011. The Interna- tional Organization for Standardization (ISO) produced a new method (7). Australia/New Zealand(Aus/NZ) published a revised method (8) that mirrors the ISO method (7). None Address all correspondence to Michael Caswell at mcaswell@cptclabs.com.

JOURNAL OF COSMETIC SCIENCE 298 of the research published herein used the FDA’s Final Rule, the ISO standard, or the re- vised Aus/NZ methods to evaluate SPF. Differences in these methodologies, including panel size, time frame for erythemal evalu- ation, geometric progression of UV dose, reference sunscreen formulations, and statistical criteria have been noted (9) and are shown in Table I. The mere existence of these differ- ences has prevented international harmonization of SPF testing. However, the actual im- pact of these methodological variations on SPF values has not yet been reported. Herein, we report SPF values on the same formulations using the COLIPA International (Interna- tional) method, the Aus/NZ method, and the FDA Final Monograph (FDA-FM) method. The statistical analysis of the disparities between SPF values generated by these three methodologies shows that no statistically signifi cant differences exist. MATERIALS AND METHODS METHODS Protocols based on the COLIPA International SPF test method (5,6), the FDA-FM SPF test method (1) and the Aus/NZ standard SPF test method (4) were approved by Allendale Institutional Review Board and used to evaluate the SPF of sunscreen formulations. Se- lected details for each method are listed in Table I. Using the FDA and Aus/NZ, 28 formu- lations were evaluated 36 formulations were evaluated using the International and FDA method and 29 formulations were evaluated using the International and Aus/NZ Method. Formulations designated numbers 1 through 17 were evaluated by all three methods. A total of 59 formulations were evaluated in the course of 135 clinical trials (Table II). The trials were conducted between October 10, 2005, and May 20, 2011, in harmony with the World Medical Association Declaration of Helsinki (as amended), International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceu- ticals for Human Use, Good Clinical Practice and Standard Operating Procedures at Consumer Product Testing Company, Inc. Potential subjects were recruited from the database at Consumer Product Testing Company, Inc. Potential subjects were given a verbal description of the risks and benefi ts of the trial. They were allowed to ask questions to which they received answers in terminology that they understood. Upon completion of the informed consent process, each potential sub- ject executed an informed consent form by signing and dating the document. The poten- tial subject then became a subject in the trial. UV RADIATION SOURCE Xenon Arc Solar Simulators from Solar Light Company, Philadelphia, PA, (150 Watt or 300 Watt) were used as the source of UV radiation (10). The spectral output for the 150 W and the 300 W was essentially identical (11). The lamp output was measured with a UV intensity meter (Model PMA2100, Solar Light Company, Philadelphia, PA) before and after the test period. Solar simulators were equipped with 1-mm UG11 and WG320 fi lters, providing a spectral output in the UV range (290–400 nm) comparable to that of