Method for determining an integral sun protection factor encompassing UVA and UVB radiation

摘要

The invention relates to a method for determining an integral sun protection factor (∫ SPF or iSPF) which encompasses both UVA and UVB radiation and can be used for classifying cosmetic and dermatological sunscreens. The method comprises the steps of applying a defined amount of the sunscreen onto a defined area of a skin substrate impregnated with a spin trap, exposing the skin substrate to a defined amount of UVA- and UVB rays by a sun simulator, subjecting the skin substrate exposed to radiation to an electron spin resonance (ESR) measurement, recording the number of free radicals trapped as a real numberx1012 free radicals/mg of skin sample, and determining the integral sun protection factor ∫ SPF according to the equations (1) and (2) and (8) $\begin{array}{cc}\int SPF=\frac{E_0}{E}& \left(1\right)\\ {\log }_{10}\left(E\right)=a.{\log }_{10}\left(X.1000\right)+b& \left(2\right)\\ E={10}^{\log 10\left(E\right)}.& \left(8\right)\end{array}$