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On the Validity of Beer–Lambert Law and its Significance for Sunscreens
Author(s) -
Herzog Bernd,
Schultheiss Amélie,
Giesinger Jochen
Publication year - 2018
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12861
Subject(s) - sun protection factor , beer–lambert law , transmittance , human skin , sunscreening agents , irradiation , materials science , law , optics , chemistry , optoelectronics , dermatology , physics , medicine , biology , political science , genetics , skin cancer , cancer , nuclear physics
The sun protection factor (SPF) is the most important quantity to characterize the performance of sunscreens. As the standard method for its determination is based on clinical trials involving irradiation of human volunteers, calculations of sunscreen performance have become quite popular to reduce the number of in vivo studies. Such simulations imply the calculation of UV transmittance of the sunscreen film using the amounts and spectroscopic properties of the UV absorbers employed, and presuppose the validity of the Beer–Lambert law. As sunscreen films on human skin can contain considerable concentrations of UV absorbers, it is questioned whether the Beer–Lambert law is still valid for these systems. The results of this work show that the validity of the Beer–Lambert law is still given at the high concentrations at which UV absorbers occur in sunscreen films on human skin.