Table I The SPF Values of the Homosalate Reference, COLIPA Reference, OMC Lotion, and OMC Liposomes Determined by In Vivo Method in Ten Subjects with Different Skin Types Sunscreen Sl S2 S3 S4 S5 S6 S7 S8 S9 Sl0 SPF (mean ± SD) Homosalate reference 4 4.46 4.56 4.90 4 4.92 3.62 4.44 5.63 4.05 4.35 ± 0.64 COUP A reference 12.4 15.5 19.4 14.5 17.1 12.4 15.5 15.5 12.4 19.4 15.2 ± 3.4 OMC lotion 14.2 15.5 12.4 12.3 15.5 17.1 12.3 12.4 15.5 12.3 13.95 ± 1.83 OMC liposomes 17.1 19.3 19.4 12.4 15.5 14.5 19.4 17.1 14.5 15.5 16.57 ± 1.40 'ij rn � n C '"""1 z rn 0 C C/) b:l C/) 0 � 'ij '"""1 0 0 1-rj 0 � n \..)J \0 .......

392 JOURNAL OF COSMETIC SCIENCE DETERMINATION OF HUMAN PERCUTANEOUS ABSORPTION OF OMC BY STRIPPING TEST Figure 2 shows the percentage of OMC recovered in the total number of rape strips removed after different rimes of application. The results indicated that after 30 minutes, the percentage of OMC in total strips in the MLVs, o/w emulsion, and SUVs are 98.8% ± 10.4, 97.5% ± 10.9, and 57.7% ± 2.7 (mean ± SD) after 3 hours, 89.2% ± 7.3, 60.5% ± 2.8, and 40.8% ± 1.8 after 5 hours, 70.3% ± 2.3, 53.3% ± 4.3, and 21.7% ± 1.2 and after 7 hours, 38.4% ± 2.1, 29.1% ± 2.9, and 20.6%±1.6, respec­ tively. After 30 minutes of application, there were no significant differences in the total skin accumulation of OMC in the ML Vs and the o/w emulsion. After 3-, 5-, and 7-hour applications, the total skin accumulation of OMC in the MLVs was significantly (p 0.001) more than that of the SUVs and the conventional o/w emulsion. The results presented in Figures 3-6 show the amount of OMC in the stratum corneum as a function of stripping numbers (groups of strips), from different formulations. These figures show the amount of OMC in different layers of the stratum corneum. In general, higher amounts of sunscreen were recovered from the upper layers of the stratum corneum at 30 minutes post-application. Ar 3, 5, and 7 hours post-application, almost similar depth of penetration profiles were obtained. Figure 3 shows the amount of OMC after 30 minutes in different strip groups as different layers of the stratum corneum. There were no significant differences in the amount of OMC in the ML Vs and the o/w emulsion formulation. After 3, 5 and 7 hours, the amount of OMC in the first strip group was significantly (p 0.001) less than that in the conventional lotion however, the amount of OMC in the total layers was significantly more than that in the o/w emulsion and the SUVs (Figures 4-6). In the SUV formulation the amount of OMC in all strip groups was significantly (p 0.05) less than that in the ML Vs and the o/w emulsion. DISCUSSION Sunscreen have been widely recommended and used as protective films against sunburn, photo-aging, and skin cancer (14). Since sunscreens are applied to large areas of the body, 120 � 100 l ao § 60 I. W 40 20 0 ns 0.5 h 3h -lfLV O/W emulsion c:::::J SUV 5h 7h Figure 2. Percent of OMC recovered in the total number of tape strips removed after 0.5 , 3, 5, and 7 hours post-application. Values are the mean ± SD, n = 6 ns p 0.05, **p 0.01, ***P 0.001 vs MLV.