The aim of the study was to determine 'outdoor' the sun protection factor (SPF) of a high SPF suncreen and to compare it with the claimed 'indoor' SPF. Methods. An 'outdoor' study on the efficacy of a high SPF sunscreen has been carried out at 3200 m a.s.l.. Eleven healthy volunteers, with fair skin, have been enrolled: all of them were skilled mountaineers. The aim of the study was to calculate the sun protection factor of the sunscreen in extreme environmental conditions. The exposures were monitored with a Robertson-Berger radiometer (UV 501 Biometer). The test has been performed in accordance with the FDA suggestions for 'outdoor' testing of sunscreens, with a few methodological improvements that have been recently introduced by the COLIPA European method for SPF testing. The amount of product applied on the skin was less than the standard quantity of 2 mg/cm2 in order to avoid lengthy exposure times. Results. The resulting 'outdoor' SPF for the tested sunscreen, containing only physical blockers, and with a claimed SPF 'indoor' of 15, was 9,72. The gap between outdoor SPF and 'indoor' SPF, in our study, was slightly minor compared to that reported in other outdoor studies that took place at the sea level. The resulting SPF was considered as acceptable for a test in which the environmental factors were particularly severe (high altitude, climatic variations). Some limitations typical of sunscreens containing only mineral particles, and that may reduce their photoprotective efficacy in severe environmental conditions, are pointed out (lack of uniform distribution of the product on the skin, low water resistance). Conclusions. The conclusion is drawn that the described method represents an improvement in 'outdoor' tests and that it may be useful to verify the level of photoprotection offered by a given sunscreen in real use conditions.
|Translated title of the contribution||'Outdoor' determination at high altitude of the sun protection factor of a high SPF sunscreen|
|Number of pages||7|
|Journal||Giornale Italiano di Dermatologia e Venereologia|
|Publication status||Published - 1998|
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