Determination of ultraviolet A protection factor of sunscreens

Sunscreen products are among the most important ways for skin protection against sunburn, early skin aging and skin cancer. Due to existing wide variation of sunscreens, it is necessary to assure their protection ability against the sun damage. Performance assessment of sunscreen products against UVA is expressed by sun UVA protection factor (UVA-PF). Because currently these factors are determined in foreign countries at high cost, developing a comprehensive protocol for UVA-PF determination in Iran would have distinct benefits.
The two standards, CEN 2006 and FDA 2007, introduce persistent pigment darkening (PPD) method for UVA-PF in vivo determination, while following the same principles are different in details. For in vitro UVA-PF determination, 4 standards CEN 2006, FDA 2007, FDA 2011 and ISO 24443 provided protocols, which two of them (CEN 2006 and FDA 2011) proposed critical wavelength method. On the other side, FDA 2007 offered modified Diffey method. ISO 24443 approved that and considering in vitro UVA-PF determination correlated with PPD method.
In this review, complete documents were collected, and the available facilities and setups, with cooperation of Iran Center for Food and Drug Control Labs, a comprehensive UVA-PF determination protocol for Iranian sunscreen products was developed.