Improving sensoriality of W/O mineral sunscreen

ABSTRACT

Sensoriality is a key factor in sunscreen products, as they must be applied several successive times to ensure effectiveness. To formulate a nice sensorial sunscreen product is not an easy task. In addition, sunscreens must be designed not only focusing on skin protection and water resistance, but also considering the human health impact of cosmetics and environmental aspects such as the prevention of ocean pollution by using safe ingredients. Sunscreens are mostly formulated as emulsions (creams and lotions) that incorporate UV filters both organic and inorganic ones. Inorganic UV filters are considered more ocean friendly, and they are easier to formulate in a water-in-oil (W/O) than in an oil-in-water (O/W) system. Nevertheless, inorganic UV filters can produce a whitening effect, and a high amount of oil phase is needed to disperse them. This can lead to a greasy and heavy feeling after application. Moreover, W/O emulsions show fewer lighting textures and heavier residues on the skin than O/W systems. In order to overcome these formulation challenges, Kao proposes the use of two specific ingredients: Exceparl LM-LC (Lauryl Lactate) as a solubilizer for UV filters with high solubility capacity and a low whitening effect, and Penetol GE-IS (Isostearyl Glyceryl Ether) as an emulsifier that forms liquid crystals in W/O emulsions with a higher internal phase content, affording a lighter and non-oily feel of the skin. 

Formulating sunscreens is really challenging. Achieving a stable formulation with high enough sun protection can be difficult. Moreover, one of the claim categories of sun care products that have experienced the largest growth over the last three years is the Ethical and Environmental claim, based on Mintel database sources.