The interest in Pickering emulsions is based on the possibility of replacing classical emulsifiers with solid particles. These emulsions are very attractive in the pharmaceutical field for their stability virtues and as a vehicle to deliver active ingredients. The study aimed to analyze the properties of the residual film of the Pickering emulsions on the human skin compared to conventional systems. For this project, three types of solid particles were used: titanium dioxide, zinc oxide and silicon dioxide. All of them are capable of stabilizing the oil/water interface and thus forming totally emulsified systems. To create an emulsion of reference, a classical surfactant was used as an excipient. Complementary systems containing both particles and the emulsifier were also analyzed. Then, a combined approach between physicochemical and biometrological in vivo analysis was employed. The study proved that Pickering emulsions stabilized by the metal oxides were distinct from the reference emulsion in terms of droplet sizes and organization, rheological and textural responses. Consequently, it impacted the properties of the residual film once the product was applied to the skin. The particle-stabilized emulsions formed a hydrophobic film counter to conventional excipients. Also, the Friction parameter (or the roughness of the film) was directly linked to the quantity of the particles used in the formulation and their perception on the skin surface. The use of the particles blurs the glossy effect of the oil phase. Finally, it was observed that the appearance of the residual film was impacted by the type of the particle, namely TiO 2 and ZnO particles.

An evaporation study was conducted on the skin of several volunteers to examine whether skin properties influence fragrance molecules’ evaporation rates. The aim was to identify the observed variations and explore the responsible fragrance molecular and skin factors. To study the evaporation phenomenon, fragrance molecules evaporation was semi‐quantified from each volunteer's skin. This approach allowed a comparison of evaporation across individuals and provided insights into how the fragrance molecules interacted differently depending on skin types. Skin properties were subsequently measured to explain the observed differences in evaporation between individuals. Statistical analysis was performed to understand how both skin type and the intrinsic properties of fragrance molecules contribute to the observed variations in evaporation rates. This study offers promising results, advancing our understanding of the evaporation behaviour of fragrance molecules and its relationship with the physicochemical properties of the skin and the intrinsic characteristics of the fragrances.