Hedayat Kamand, Ahmad Nasrollahi Saman, Firooz Alireza, Rastegar Hossein, Dadgarnejad Manouchehr
Center for Research and Training in Skin Diseases and Leprosy (CRTSDL), Tehran University of Medical Sciences (TUMS), Tehran, Iran.
Cosmetic Products Research Center, Iranian Food and Drug Administration, Ministry of Health and Medical Education, Tehran, Iran.
Clin Cosmet Investig Dermatol. 2020 May 8;13:351-358. doi: 10.2147/CCID.S244898. eCollection 2020.
In the past, it was taught that UVA wavelengths (320- 400nm) only plays a major role in skin aging but recently the scientific researches also show that UVA cause cancerous keratinocyte cells in deep layer of the epidermis. Therefore, the protective ability of the product against UVA is important in addition to protection against UVB rays. The UVA protective factor (UVA-PF) is used to evaluate the effectiveness of sunscreen products against UVA rays. This study aims to review and compare all outstanding protocols in the field of UVA-PF measurement and finally the introduction of the best method of measuring UVA-PF based on the further benefits.
Four standards including ISO 24443 (AS/NZS 2604: 2012 recommended approach), CEN 2006, FDA 2007 and FDA 2011 are selected.
In order to measure UVA-PF with in vivo method, two standards of CEN 2006 and FDA 2007 recommended persistent pigment darkening (PPD) method. Although the general principle of both is similar, there are some differences in detail. For in vitro measurement of UVA-PF, CEN and FDA 2011 standards use critical wavelengths. FDA 2007 introduces the modified Diffey fraction, and ISO 24443 standard meets the UVA-PF measurement in a manner that is consistent with PPD.
Finally, this review discussed the comparison of all in vitro and in vivo UVA-PF measurement standards and provided information in the form of texts and tables to move towards the creation of an integrated standard. Since in vitro methods of UVA-PF measurement are not reproducible due to differences in test conditions, it may be concluded that the in vivo PPD method is a more suitable option.
过去人们认为紫外线A波段（320 - 400纳米）仅在皮肤老化过程中起主要作用，但最近的科学研究表明，紫外线A还会引发表皮深层的角质形成癌细胞。因此，产品抵御紫外线A的能力除了防紫外线B之外也很重要。紫外线A防护系数（UVA - PF）用于评估防晒产品抵御紫外线A的效果。本研究旨在回顾和比较紫外线A防护系数测量领域的所有优秀方案，并最终基于更多优势介绍测量紫外线A防护系数的最佳方法。
选择了四项标准，包括ISO 24443（AS/NZS 2604: 2012推荐方法）、CEN 2006、FDA 2007和FDA 2011。
为采用体内方法测量紫外线A防护系数，CEN 2006和FDA 2007这两项标准推荐了持续色素沉着（PPD）方法。虽然两者的总体原理相似，但在细节上存在一些差异。对于紫外线A防护系数的体外测量，CEN和FDA 2011标准使用临界波长。FDA 2007引入了修正的迪菲分数，而ISO 24443标准以与PPD一致的方式进行紫外线A防护系数测量。
最后，本综述讨论了所有体外和体内紫外线A防护系数测量标准之间的比较，并以文本和表格的形式提供信息，以推动建立一个综合标准。由于紫外线A防护系数测量的体外方法因测试条件不同而不可重复，因此可以得出结论，体内PPD方法是更合适的选择。
