Establishment of a Human Organotypic Skin Explant Culture as an alternative method to assess efficacy and safety of sunscreens: Employment of Zinc Oxide nanoparticles as a validation tool and comparison with the results obtained in the culture medium

• Grant number: 18/16075-3
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2019
• End date: April 30, 2021
• Field of knowledge: Health Sciences - Pharmacy - Pharmaceutical Technology
• Principal Investigator: Maria José Vieira Fonseca
• Grantee: Maria José Vieira Fonseca
• Host Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated researchers: Geórgia de Assis Dias Alves ; Patrícia Maria Berardo Gonçalves Maia Campos

Abstract

Exposure to the ultraviolet radiation is the main risk factor for the development of skin cancer. Special attention should be given to long-term exposure because it is primarily responsible for premature aging and skin cancer. Safety and efficacy studies evaluate sunscreens under acute conditions of exposure to the ultraviolet radiation, which is not consistent with the actual conditions of use of the product. Thus, the first objective of this work is to validate the establishment of an organotypic skin culture that remains viable for 30 days and can be exposed to several cycles of radiation. In April of 2016, the Annex VI of the EU Cosmetics Regulations was amended to establish that zinc oxide (ZOn) nanoparticles are safe for use as filters in sunscreens. Since then, there has been a continuing debate on the safety of topical application of ZOn since the Zinc oxide opinion document published by SCCS mentions several papers about ZOn that are hardly relatable to each other. This is because many studies have developed the nanoparticles themselves or evaluated only certain parameters, such as physical characteristics of the nanoparticles, or only their penetration into the skin. Therefore, the second objective is to evaluate the safety and efficacy of the topical use of ZOn, which will validate the organotypic skin culture. The third objective is to compare the results obtained for the organotypic skin culture with the culture medium, aiming to speed the methodological execution time. This stage has great relevance because it reduces the time to carry out the experiments, which is of the utmost importance for the industry. Therefore, we will determine the parameters that can be evaluated in the culture medium without compromising the correct interpretation of the results. (AU)