Characteristics and Performance of Inorganic UV Filter-Based Sunscreens

The effective attenuation of UV radiation is the most important characteristic of inorganic UV filters used for photoprotection applications. However, the performance and suitability of inorganic UV filters for use in sunscreen formulations also depend on other factors related to particle and formulation properties. This chapter presents the desired characteristics of inorganic UV filters and discusses the performance of the two most widely used inorganic UV filters, ZnO and TiO2, concerning these characteristics. The background and methods used to measure the different factors determining the efficacy of sunscreen, such as sun protection and UVA protection factors, are also covered in this chapter.