Table V Test Articles and Their Respective UVAI/UV Ratios Obtained with Labsphere UV 2000S and with Vitro Skin ® N-19 and Roughened Quartz (Q-glass) Substrates Commercial sunscreen products Experimental A C D E K L N P Boots Five Star 2156-16 2156-18 Actives SPF-15 SPF-15 SPF-15 SPF-30 SPF-30 SPF-25 SPF∼50 SPF∼30 Avobenzone 3 2 3 + + 3 3 Octocrylene 10 2.35 + + 2.3 2 Homosalate 10 8 + Octisalate 5 4 + + Oxybenzone 5 3 5 Octinoxate 7.5 + Bemotrizinol (USAN) + 2 2.3 Bisoctrizole (USAN) active 6 3.5 Diethylhexyl butamido triazone + Pre-irradiation dose, MED 10 10 10 20 20 17 33.3 20 Vitro Skin UVAI/UV ratio 0.905-0.926 0.469-0.519 0.750-0.787 0.853-0.862 0.880-0.893 0.734-0.736 0.960-0.964 0.950-0.954 Q-Glass UVAI/UV ratio 0.929 0.912 0.948-0.955 FDA UVA rating High Medium High High High High Highest Highest CHALLENGES TO SUNSCREEN EVALUATION 595

JOURNAL OF COSMETIC SCIENCE 596 FDA. Absorbance spectra of all test articles obtained on alternative substrate Vitro Skin® N-19 were within the dynamic range of the Labsphere UV 2000S (Figure 4). Figures 3 and 4 also show that the experimental products N and P, with the “highest” UVA rating, pro- duce a characteristic “fl at” absorbance spectra. Results presented in Table V demonstrate that the UVAI/UV ratios of test articles A (SPF 15), E, and P (SPF 30) obtained with the Labsphere UV 2000S on the alternative sub- strate, Vitro Skin® N-19, are similar to the ratios obtained on roughened quartz plates. However, CV values were much higher than the required 10% or less for products tested on quartz plates. After irradiation, the majority of the US commercial sunscreens tested belong to medium- or high-UVA protection categories. Two experimental sunscreens containing the broad-spectrum photostable actives bisoctrizole and bemotrizinol in con- junction with avobenzone and octocrylene were able to achieve the “highest” UVA rating category. Data in Table VI show that the UVAI/UV ratios of tested sunscreens obtained on both transmittance analyzers the Labsphere UV 2000S and the Optometrics SPF 290S with Vitro Skin® N-19, were comparable for the majority of test articles however, in some instances these ratios were slightly higher when the Labsphere UV 2000S was utilized. Table VI Test Articles and Their Respective UVAI/UV Ratios Obtained with Optometrics SPF-290 and Labsphere UV 2000S and with Vitro Skin® N-19 as Substrate Commercial sunscreen products A C D E K L Boots Five Star Actives SPF-15 SPF-15 SPF-15 SPF-30 SPF-30 SPF-25 Avobenzone 3 2 3 Octocrylene 10 2.35 Homosalate 10 8 Octisalate 5 4 Oxybenzone 5 3 5 Octinoxate 7.5 Bemotrizinol (USAN) Bisoctrizole (USAN) active Diethylhexyl butamido triazone Pre-irradiation dose, MED 10 10 10 20 20 17 Optometrics SPF-290S UVAI/ UV ratio 0.857- 0.882 0.441- 0.475 0.727- 0.753 0.823- 0.837 0.884- 0.891 0.743- 0.744 Labsphere UV-2000S UVAI/ UV ratio 0.905- 0.926 0.469- 0.519 0.750- 0.787 0.829- 0.862 0.880- 0.893 0.734- 0.736 FDA UVA rating High Medium High High High High