Optimising sunscreen delivery via UV filter use

While it is well known (and intuitively understood) that SPF is dependent on the type and concentration of UV filters incorporated in a formulation, what is sometimes overlooked is the vital role played by the formulation itself. This article discusses the influence of various aspects of the formulation on product efficacy, and aims to provide the formulator with some guiding principles to optimise the effectiveness of UV filters in finished products.

At first glance, formulating sun protection products is straightforward for anyone who already has the practical skills to make a skin care formulation. Most sun care products are formulated as emulsions, so it would appear to be a simple matter of taking a stable skin care emulsion system and slotting in some UV filters. There is now even an online tool to help in selecting which filters to use, and at what concentrations, to achieve the desired SPF and UVA protection properties.1 However, while this approach will give a product that provides UV protection, making a commercially viable sun care product is more of a challenge. Today’s sun care formulators need to squeeze more and more efficacy from the active ingredients, as they try to achieve high SPF and UVAPF while minimising cost. Many factors influence the efficacy of UV filters in final formulations, and the formulator must be aware of these factors and how to optimise them in order to achieve high SPF in a cost-effective, elegant formulation.

Fundamental requirements