A NEW BROAD-SPECTRUM SUNSCREEN 73 7 q 6 -- PF 4- 3 0 2% 4% 6% 8% 10% MDC/Boehmite (1/1) Figure 4. Dose dependency of the preventive effect of MDC-boehmite (1/1) complex on Osram lamp-in- duced erythema of human back skin. The skins were treated (2 mg/cm 2) with samples of W/O-type emulsion containing MDC-boehmite (1/1) on five separate areas and ten minutes later were irradiated once with an Osram lamp (0.41 mW/cm2). n = 5. PF = protection factor. 5 0 0-8 2-6 4-4 6-2 8-0 MDC-Boehmite/P-MCX% Figure 5. Preventive effect of MDC-boehmite (1/1) combined with P-MCX on SE lamp-induced erythema of human back skin. The skins were treated (2 mg/cm 2) with samples of W/O-type emulsion containing MDC-boehmite (1/1) and P-MCX on five separate areas and ten minutes later were irradiated once with an SE lamp (0.41 mW/cm2). n = 5. PF = protection factor.

74 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 11 PF 6 5 4 3 2 1 0 0-8 2-6 4-4 6-2 8-0 MDC-Boehmite/P-MCX% Figure 6. Preventive effect of MDC-boehmite (1/1) combined with P-MCX on Osram lamp-induced erythema of human back skin. The skins were treated (2 mg/cm 2) with samples of W/O-type emulsion containing MDC-boehmite (1/1) and P-MCX on five separate areas and ten later were irradiated once with an Osram lamp (0.41 mW/cm2). n = 5. PF = protection factor. 9---- •_- •L 7 •--- 6 - UV 0 2 6 10 12 Boehmite % UV 0 2 6 10 12 UV 0 2 6 10 12 Boehmite % Boehmite % 13 day 22 day 7 day Figure 7. Preventive effect of MDC-boehmite complex (MDC 6%, boehmite 0-12%) on UVA-induced hyperpigmentation of tortoiseshell guinea pig skin as revealed by color difference. The experimental an- imals were treated (2 mg/cm 2) with samples consisting of MDC-boehmite aqueous solution on five separate areas and ten minutes later were irradiated for two hours with UVA light (3.1 mW/cm2). This process was repeated daily for eight days. n = 9. AL = color difference.