Anhydrous Cosmetic Formulations: An Approach to Sustainable Production and Photoprotective Effectiveness

Resumen

This research focuses on the development of a solid stick sunscreen designed to provide effective photoprotection through a practical application format. The methodology followed three main stages: (1) selection of UV filters and components using BASF’s Sunscreen Simulator to estimate the theoretical Sun Protection Factor (SPF), fostering innovation in the cosmetic industry (SDG 9); (2) establishment of the formulation and manufacturing of the solid prototype; and (3) a comparative analysis of physicochemical and sensory properties between the formulated product and a commercial liquid sunscreen. Physicochemical characterization (pH, dropping point) and microbiological testing were conducted to ensure safety using the preservative Euxyl PE 9010. Furthermore, a sensory evaluation assessed texture, scent, color, application, and skin feel. Key results demonstrate that the synergy between physical filters (titanium dioxide and zinc oxide) and chemical filters (Uvinul A Plus, Uvinul MC 80, and Uvinul T 150) ensures broad-spectrum protection, contributing to public health (SDG 3). The formulated sunscreen exhibited a pH of 6.71, a dropping point of 76 °C, and a mesophilic aerobic count of 50 CFU/g, validating its stability and safety. Sensory analysis revealed a high preference for the prototype, with participants only suggesting a more intense aroma. The solid format eliminates the need for water in the formulation and extends shelf life, aligning with sustainable production practices (SDG 12). This study validates the efficacy and stability of the stick format as a viable, sustainable alternative to traditional liquid formulations.