Consumer and Personal Products Worldwide, Unit of Johnson & Johnson Consumer Companies Inc., Skillman, NJ, USA.
Photodermatol Photoimmunol Photomed. 2009 Dec;25(6):298-304. doi: 10.1111/j.1600-0781.2009.00469.x.
BACKGROUND/PURPOSE: Assessing the ultraviolet (UVA) protection factor of sunscreen formulations has been discussed for the past 20 years. The purpose of this study is to correlate the measurements of the UVA protection factor value (PFA value) via in vivo diffuse reflectance spectroscopy (DRS) and to compare this method with the in vitro method of measuring the PFA value, as well as with the in vivo persistent pigment darkening (PPD) and PFA methodologies.
The UVA protection factor via DRS technique was assessed in two clinical studies. The first study was performed in 12 subjects and the second one consisting of 10 subjects. All subjects in these studies had Fitzpatrick skin phototypes II-IV. DRS measurements were performed using a SkinScan spectrofluorimeter (Spex SkinScan, Yvon Horiba). The in vitro PFA measurements were performed using Labsphere UV-1000s UV Transmission Analyzer.
The results obtained from the non-invasive DRS studies were used to correlate with the in vitro testing and with the in vivo PFA/PPD multicenter study. A positive relationship (regression coefficient r(2)=0.90) of PFA values was found between in vitro PFA testing and the in vivo DRS testing. There was also a very good correlation (regression coefficient r(2)=0.99) between the in vivo PFA/PPD values and UVA protection factor obtained from the DRS method.
This paper presents studies using the DRS technique to assess the UVA protection factor in different sunscreen formulae correlating with in vitro and in vivo PFA/PPD values. It is a fast method, non-invasive and does not involve any subject irradiation. The technique is a good estimator for the in vivo UVA protection factor as well as a way to assess, in vivo, the photostability of sunscreen formulation in the UVA.
背景/目的：过去 20 年来，人们一直在讨论评估防晒配方的紫外线 A 防护因子（UVA-PF）。本研究的目的是通过体内漫反射光谱（DRS）来关联 UVA-PF 值的测量，并将该方法与体外测量 UVA-PF 值的方法以及体内持久色素沉着（PPD）和 UVA-PF 方法进行比较。
在两项临床研究中评估了 DRS 技术的 UVA-PF。第一项研究在 12 名受试者中进行，第二项研究由 10 名受试者组成。所有这些研究中的受试者均为 Fitzpatrick 皮肤光型 II-IV。DRS 测量使用 Spex SkinScan 分光光度计（Spex SkinScan，Yvon Horiba）进行。体外 PFA 测量使用 Labsphere UV-1000s UV 透射分析仪进行。
从非侵入性 DRS 研究中获得的结果用于与体外测试和体内 PFA/PPD 多中心研究相关联。在体外 PFA 测试和体内 DRS 测试之间发现了 PFA 值的正相关关系（回归系数 r(2)=0.90）。体内 PFA/PPD 值与 DRS 方法获得的 UVA 保护因子之间也存在很好的相关性（回归系数 r(2)=0.99）。
本文介绍了使用 DRS 技术评估不同防晒配方的 UVA 保护因子的研究，该技术与体外和体内 PFA/PPD 值相关联。它是一种快速、非侵入性的方法，不涉及任何受试者照射。该技术是评估体内 UVA 保护因子的良好指标，也是评估 UVA 中防晒配方光稳定性的体内方法。
