Clinical, Cosmetic and Investigational Dermatology (May 2020)
Comparison of UVA Protection Factor Measurement Protocols
Abstract
Kamand Hedayat,1 Saman Ahmad Nasrollahi,1,2 Alireza Firooz,1,2 Hossein Rastegar,2 Manouchehr Dadgarnejad3 1Center for Research and Training in Skin Diseases and Leprosy (CRTSDL), Tehran University of Medical Sciences (TUMS), Tehran, Iran; 2Cosmetic Products Research Center, Iranian Food and Drug Administration, Ministry of Health and Medical Education, Tehran, Iran; 3Iranian Food and Drug Administration, Ministry of Health and Medical Education, Tehran, IranCorrespondence: Saman Ahmad NasrollahiCenter for Research and Training in Skin Diseases and Leprosy (CRTSDL), Tehran, University of Medical Sciences (TUMS), No. 415 Taleqani Avenue, Tehran 1416613675, IranTel/Fax +982188963804Email [email protected]: 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.Materials and Methods: Four standards including ISO 24443 (AS/NZS 2604: 2012 recommended approach), CEN 2006, FDA 2007 and FDA 2011 are selected.Results: 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.Conclusion: 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.Keywords: sunscreen, ultraviolet, UVA protection factor, in vivo, in vitro
