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Photoprotection against visible light‐induced pigmentation
Author(s) -
Ruvolo Eduardo,
Fair Michael,
Hutson Ashley,
Liebel Frank
Publication year - 2018
Publication title -
international journal of cosmetic science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 62
eISSN - 1468-2494
pISSN - 0142-5463
DOI - 10.1111/ics.12502
Subject(s) - photoprotection , in vivo , sun protection factor , visible spectrum , action spectrum , in vitro , dermatology , absorbance , human skin , absorption (acoustics) , chemistry , pigment , medicine , biology , materials science , optics , photochemistry , biochemistry , optoelectronics , chromatography , physics , genetics , photosynthesis , organic chemistry
Objective This paper presents in vivo an in vitro studies demonstrating the induction of pigmentation in human skin by visible light which can be blocked by using formulation containing the correct amount of yellow iron oxide ( YIO ). Methods An in vitro absorption method was developed to determine the protection provided by a test formulation containing 4.5% YIO using an IPD UVA ‐ VIS action spectrum. Following the development of the in vitro method and in vivo study with 10 normal healthy volunteers with Fitzpatrick skin phototypes IV to VI was conducted to verify if the predictive model. Results The in vitro model for visible light protection provided a protection factor of 2.5 using the in vitro absorption spectrum of 4.5% of YIO with a very similar result from the in vivo study with a protection factor of 3.0. Multiple daily exposures of visible light have shown increase in skin pigmentation and the application of YIO provide less development of pigmentation when compared to unprotected skin. Conclusion In vitro testing of the absorbance of the pigmented formulation using a proposed action spectrum for immediate pigment darkening ( IPD ) response in the visible light range supports the in vivo protection observations for persistent pigment darkening ( PPD ) and can be used as predictor for skin pigmentation induced by visible light.