Broad spectrum UV protection by crystalline organic microrod sunscreens

Ultraviolet (UV) light has the potential to cause many adverse effects on the body including causing the cancers melanoma and squamous cell carcinoma. The use of sunscreens to protect against these harmful effects has become common practice. However, many of the sunscreens currently being used have the ability to cross the skin barrier and enter the body. These components can produce reactive oxygen species inside the body which can cause damage to cells. We have developed a sunscreen product that contains organic particles that are too large to diffuse into the skin. These particles are formed from four FDA approved UV blocking molecules that are solids at room temperature. The components are first mixed together, melted, and then emulsified in water and allowed to cool. Once cooled, the particles slowly crystallize in the solution forming sphere to rod-like particles about one micron wide and one to tens of microns in length. SPF measurements of the samples showed comparable results to two commercially available sunscreens with SPFs of 50. The particles were shown to maintain their excellent UV blocking properties after exposure to UV light and show great promise as possible sunscreens. (C) 2015 Elsevier B.V. All rights reserved.