A novel method for evaluating sun visible light protection factor and pigmentation protection factor of sunscreens
Received 18 April 2019
Accepted for publication 13 August 2019
Published 28 August 2019 Volume 2019:12 Pages 605—616
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 2
Editor who approved publication: Dr Jeffrey Weinberg
Sérgio Schalka,1 Marcelo de Paula Corrêa,2 Leticia Yumi Sawada,1 Camila C Canale,3 Thayna N de Andrade4
1Department of Dermatology, Medcin Clinical Research Center, Osasco, Brazil; 2Institute of Natural Resources, Federal University of Itajubá, Itajubá, Brazil; 3Department of Pharmacy, Medcin Clinical Research Center, Osasco, Brazil; 4Department of Photoprotection, Medcin Clinical Research Center, Osasco, Brazil
Correspondence: Sérgio Schalka
Department of Dermatology, Medicine Clinical Research Center, Rua Atílio Delanina 178
, Osasco 06023-000, SP, Brazil
Tel +55 113 654 2054
Introduction: The role of visible light (VL) in the process of skin pigmentation by solar radiation has been demonstrated. Sunscreens with the presence of pigments, particularly iron oxide (IO), have a greater protective effect against VL and are, therefore, highly recommended for prevention and treatment of hyperpigmentation disorders. This study aimed to evaluate 33 sunscreen formulations, and through spectrophotometric measurements, proposes new methods to evaluate the VL protection factor and the pigmentation protection factor.
Methods: 33 sunscreen formulations marketed in Brazil were evaluated, including 17 products containing pigments and 16 products with no pigments. Spectrophotometric measurements were taken to determine solar VL protection factor and the pigmentation protection factor, based on the absorption curve of the product, the pigmentation action spectrum and sun spectrum.
Results: Sunscreen with pigments presented a higher solar VL protection factor and pigmentation protection factor compared to products without pigment. The statistical analysis showed a strong correlation between the solar VL protection factor and the integral of the absorption curve in the VL range and the transmittance reduction (%) in the same range. The correlation between the VL protection factor and the pigmentation protection factor was also demonstrated.
Conclusion: The VL protection factor and the pigmentation protection factor showed to be adequate metrics to estimate the effectiveness of sunscreens in the prevention of the pigmentary effect of solar VL and the pigmentary effect of the complete spectrum of immediate pigmentation.
Keywords: visible light, sunscreening agents, sun protection factor, skin pigmentation
This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution - Non Commercial (unported, v3.0) License. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms.Download Article [PDF] View Full Text [HTML][Machine readable]