Development and evaluation of broad spectrum photoprotective formulations: physicochemical, physicomechanical properties, safety and clinical efficacy

• Grant number: 19/26836-4
• Support type: Scholarships in Brazil - Doctorate (Direct)
• Effective date (Start): May 01, 2020
• Effective date (End): July 31, 2022
• Field of knowledge: Health Sciences - Pharmacy
• Principal researcher: Patrícia Maria Berardo Gonçalves Maia Campos
• Grantee: Vitória Tonini Porto Ferreira
• Home Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The safety and efficacy photoprotective products depends not only on the quality and quantity of the UV filters, but also on their interaction with the formula and the interaction of the finished product with the surface and biological response of the skin. Thus, it is essential to properly choose all formulation components, taking into account the intrinsic properties of emulsions and the biological complexity of the skin. In this context, the aim of the study is to develop broad spectrum sunscreen formulations and to evaluate the long-term effects of the addition of antioxidant active ingredients on stability, in terms of the microscopic and macroscopic properties of the formulation, and on safety and clinical photoprotective efficacy. The impact of the addition of antioxidant agents on formulations and photoprotective efficacy will be assessed by in vitro and in vivo measurements. Initially, stability will be assessed by microstructural and thermal analysis, rheology and texturometry, while the residual film surface wettability will be assessed by contact angle measurements according to the Van Oss model. Subsequently, formulations will be submitted to evaluation of the photoprotective clinical efficacy by skin imaging and biophysical techniques, to assess how cosmetic products interact with the skin in real use conditions: effects over structural and morphological characteristics of epidermis and dermis, quality and homogeneity of the photoprotective film, UV filters penetration and distribution in relation to the skin microstructures, sensory properties, SPF and other biological effects in relation to skin barrier function, hydration, skin microrelief, erythema, coloration, viscoelasticity and dermis echogenicity. Raman Confocal Spectroscopy will also be applied in vivo to determine the semi-quantitative UV filters penetration, penetration profile and extension and the hydration index. Finally, in vitro and in vivo measurements will be correlated to develop prediction models to support the development process and further the knowledge on the different physicochemical phenomena involved in these systems. (AU)