Touti Rita, Renoux Pascale, Nocairi Hicham, Douezan Stephane, Passeron Thierry, Josso Martin
L'oréal Research and Innovation, Chevilly-Larue, France.
Department of Dermatology, Côte D'azur University, Nice University Hospital Center, Nice, France.
Photodermatol Photoimmunol Photomed. 2025 Sep;41(5):e70044. doi: 10.1111/phpp.70044.
Accurate and reliable evaluation of sunscreen performance is necessary to ensure adequate balanced sun protection against ultraviolet light (UV) and high-energy visible light (HEV), depending on an individual's skin phototype and dermatoses. The objective of this study was to investigate the importance of methodological considerations for standardized evaluation of sunscreen performance to protect against UVA, especially long UVA1, and HEV.
In an open in vivo study, 6 commercial sunscreens were applied on the backs of subjects (n = 15) to evaluate the performance against UVA and HEV using a robust protocol of hybrid diffuse reflectance spectroscopy (HDRS), based on validated ISO methodology. High-resolution absorbance spectra were obtained between 310 and 450 nm using a 1 nm stepsize. The region 365-450 nm was compared with a method using linear interpolation from four discrete wavelengths (365, 405, 435 and 450 nm).
The sunscreen ranking observed using the in vivo high-resolution spectral representation (1 nm steps) method was not consistently reproduced by the method using four discrete wavelengths with linear interpolation. Differences between the two methods were observed in the range of 380-400 nm, leading to misclassification in the rank of protection depending on the methodology used.
The absorption profile in the UVA and HEV light ranges of each sunscreen was determined accurately and reliably by diffuse reflectance spectroscopy with measurements every nanometer. Sunscreen performance characterization will depend on the methodology, and applying linear interpolation from broader wavelength bands may give inaccurate results.
根据个人皮肤光型和皮肤病情况，准确可靠地评估防晒产品性能对于确保充分平衡地抵御紫外线（UV）和高能可见光（HEV）至关重要。本研究的目的是探讨方法学考量对于标准化评估防晒产品抵御UVA（尤其是长波UVA1）和HEV性能的重要性。
在一项开放性体内研究中，将6种商用防晒霜涂抹在受试者（n = 15）的背部，采用基于经过验证的ISO方法的稳健混合漫反射光谱法（HDRS）方案评估其对UVA和HEV的防护性能。使用1 nm步长在310至450 nm之间获取高分辨率吸光度光谱。将365 - 450 nm区域与一种使用四个离散波长（365、405、435和450 nm）线性插值的方法进行比较。
使用体内高分辨率光谱表示法（1 nm步长）观察到的防晒霜排名，并未被使用四个离散波长线性插值的方法一致重现。两种方法在380 - 400 nm范围内存在差异，这导致根据所使用的方法在防护等级上出现错误分类。
通过每纳米进行测量的漫反射光谱法能够准确可靠地测定每种防晒霜在UVA和HEV光范围内的吸收谱。防晒产品性能的表征将取决于方法，并且从更宽波长带进行线性插值可能会给出不准确的结果。
