SCREENING SUNSCREEN FORMULATIONS 311 in IL-lo• release. For routine practical use of the method, ability to simultaneously use all six ports is important. From the results gathered it appears that this method may prove useful as a tool for screening the SPF of sunscreens. The model is simple to use, measures a biological endpoint, and results can be obtained within 24 hours. We regard this method as a significant development. A rapid in vitro screen for determining whether a prototype sunscreen formulation minimally possesses the desired SPF is a worthwhile objective. Reliable identification of formulations significantly lacking their intended SPF would permit removal of these formulas from either pilot or final human SPF testing. Secondly, this method represents a significant achievement in the area of non-animal test methods development. Prior to the elimination or suspension of animal testing by most manu- facturers of personal care products, prototype sunscreen products were screened for SPF values in guinea pigs. This procedure clearly allows screening for SPF without the use of animals. REFERENCES (1) Sunscreen drug products for over-the-counter human use: Proposed safety, effective and labeling conditions, Fed. Reg., 43, 1978:38259-28260. (2) B. M. Cumpelik, Analytical procedures and evaluation of sunscreens, J. Soc. Cosmet. ½hem., 23, 333-345 (1972). (3) D. F. Robertson and G. A. Groves. The selection and use of topical sunscreens, &led. J. Aust., 2, 1445-1451 (1972). (4) G. A. Groves, P. P. Agin, and R. M. Sayre, In vitro and in vivo methods to define sunscreen, Aust. J. Dermatol., 20, 112-119 (1979). (5) B. L. Diffey and J. Robson, A new substrate to measure sunscreen protection factors throughout the ultraviolet spectrum. J. Soc. Cosmet. Chem., 40, 127-133 (1989). (6) C. A. Cole and R. L. Van Fossen, In vitro models for UVB and UVA photoprotection, Sunscreen Development, Evaluation, and Regulatory Aspects, 10, 395-404 (1990). (7) R. M. Sayre, P. P. Agin, D. L. Desrochers, and E. Marlowe, Sunscreen testing methods: In vitro predictions of effectiveness, J. Soc. Cosine. Chem., 31, 133-143 (1980). (8) J. C. Ansel, T. A. Luger, and I. Green, The effect of in vitro and in vivo UV irradiation on the production of ETAF activity by human and murine keratinocytes, J. Invest. Dermatol., 81, 519-523 (1983). (9) K. Punnonen, T. Puustinen, and C. T. Jansen, UVB irradiation induces changes in the distribution and release of •4C-arachidonic acid in human keratinocytes in culture, Arch. Dermatol. Res., 278, 441-444 (1986). (10) R. D. Ley, M. J. Peak, and L. L. Lyon, Induction ofpyrimidine dimers in epidermal DNA of hairless mice by UVB: An action spectrum,.]. Invest. Dermatol., 80:188-191 (1983). (11) D. L. Bissett, D. P. Hannon, and T. V. An animal model of solar-aged skin: Histological, physical, and visible changes in UV-irradiated hairless mouse skin, Photochem. Photobiol., 46(3):367-378 (1987). (12) A. K. Black, M. W. Greaves, C. N. Hensby, and N. A. Plummer, Increased prostaglandins E2 and F2tx in human skin at 6 and 24 hours after ultraviolet B irradiation (290-320 nm), Br..]. Clin. Pharmacol., 5, 431-436 (1978). (13) K. D. Cooper, P. F. Fox, and S. I. Katy, Effects of ultraviolet radiation on human epidermal cell alloantigen presentation: Initial depression of Langerhans cell dependent function is followed by the appearance of T6-DR + cells which enhance epidermal alloantigen presentation. J. Immunol., 134, 129-137 (1984). (14) T. S. Kupper, A. O. Chua, P. Flood, J. McGuire, and U. Gubler, Interleukin 1 gene expression in cultured human keratinocytes is augmented by ultraviolet irradiation, J. Clin. Invest., 80, 430-436 (1987).

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