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Calculation of the sun protection factor of sunscreens with different vehicles using measured film thickness distribution — Comparison with the SPF in vitro

Paper ID Volume ID Publish Year Pages File Format Full-Text
29473 44411 2016 8 PDF Available
Title
Calculation of the sun protection factor of sunscreens with different vehicles using measured film thickness distribution — Comparison with the SPF in vitro
Abstract

•A method for calculating sun protection factor (SPF) of sunscreens is presented.•This method utilizes measured film thickness frequency distribution of sunscreen.•Sunscreen is applied to a substrate consisting of porcine epidermal membrane.•Calculated SPF of five formulations agreed well with experimental SPF in vitro.•Method provides a tool for predicting SPF of sunscreens made with different vehicles.

The sun protection factor (SPF) depends on UV filter composition, and amount and type of vehicle of the applied sunscreen. In an earlier work, we showed that the vehicle affected the average thickness of sunscreen film that is formed upon application to a skin substrate and that film thickness correlated significantly with SPF in vitro. In the present study, we quantitatively assess the role for sunscreen efficacy of the complete film thickness frequency distribution of sunscreen measured with an oil-in-water cream, an oil-in-water spray, a gel, a water-in-oil, and an alcoholic spray formulation. A computational method is employed to determine SPF in silico from calculated UV transmittance based on experimental film thickness and thickness distribution, and concentration and spectral properties of the UV filters. The investigated formulations exhibited different SPFs in vitro and different film thickness distributions especially in the small thickness range. We found a very good agreement between SPF in silico and SPF in vitro for all sunscreens. This result establishes the relationship between sun protection and the film thickness distribution actually formed by the applied sunscreen and demonstrates that variation in SPF between formulations is primarily due to their film forming properties. It also opens the possibility to integrate the influence of vehicle into tools for in silico prediction of the performance of sunscreen formulations. For this, the use of the Gamma distribution was found to be appropriate for describing film thickness distribution.

Keywords
SPF, sun protection factor; OW-C, oil-in-water cream; OW-S, oil-in-water spray; WO, water-in-oil; CAS, clear lipo-alcoholic spray; INCI, international nomenclature of cosmetic ingredientsSun protection factor; SPF in vitro; Sunscreen; Film thickness frequ
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Calculation of the sun protection factor of sunscreens with different vehicles using measured film thickness distribution — Comparison with the SPF in vitro
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 159, June 2016, Pages 74–81
Authors
, , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us