Properties of Topical Sunscreen Formulations: A Review

Sunscreens reduce the deleterious effects of ultraviolet radiation (UVR) by absorbing, reflecting, or scattering photons. Ultraviolet radiation includes UVB, which is primarily responsible for sunburn and skin cancers, as well as UVA, which has been implicated in photoaging. Topical photoprotective agents include physical and chemical sunscreens. Physical sunscreens are important in individuals who are unusually sensitive to UVA and visible light such as those with photosensitizing diseases. Chemical sunscreens are more cosmetically appealing and can selectively absorb UVB and/or UVA. The increased awareness of the importance of sun protection has encouraged the regular use of sunscreens. This article will review physical and chemical sunscreens. The properties and vehicle design of various sunscreen formulations are also discussed.