Interoperability of 300 watt and 150 watt xenon arc solar simulators in sun protection factor and in UVA protection factor clinical testing

Summary Background The purpose of these clinical trials was to determine if 300  W and 150  W xenon arc solar simulators ( SS s) deliver the same sun protection factor ( SPF ) and UVA protection factor ( PFA ). Methods First, the SPF of the P 7 control standard and of the P 2 control standard was determined, testing 20 subjects using the method described in the Food and Drug Administration ( FDA ) F inal M onograph and using 150  W and 300  W SS s. In the second clinical trial, the PFA of the Japanese Cosmetic Industry Association ( JCIA ) control standard and of the P 2 control standard was determined, testing 10 subjects using the method described in the JCIA T echnical B ulleti n and using 150  W and 300  W SS s. Results The SPF values for P 7 control standard determined using the 150  W and 300  W SS s were 4.54 ± 0.35 and 4.61 ± 0.32, respectively. The SPF values for P 2 control standard determined using the 150  W and 300  W SS s were 17.0 ± 0.9 and 16.7 ± 0.9, respectively. The resultant PFA values for JCIA control standard determined using the 150  W and 300  W SS s were 4.06 ± 0.70 and 4.06 ± 0.70, respectively. The resultant PFA values for P 2 control standard determined using the 150  W and 300  W SS s were 3.28 ± 0.25 and 3.44 ± 0.39, respectively. Conclusion As the values are essentially identical for SPF and for PFA , the 150  W and 300  W SS s can be used interchangeably for SPF and PFA determinations.