Assessment of the applicability of the chicken embryo chorioallantoic membrane (CAM) model in toxicity and permeation studies of topical anesthetics

• Grant number: 24/11199-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: March 01, 2025
• End date: July 31, 2027
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Michelle Franz Montan Braga Leite
• Grantee: Arthur Antunes Costa Bezerra
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

The currently marketed topical anesthetic formulations for dental use have shown questionable clinical efficacy, which has led to studies focusing on the development of new formulations in different pharmaceutical forms, including microneedle (MN) systems. These systems consist of micrometric needles designed to penetrate the epithelial barrier and improve the bioavailability of the drug, in this case, anesthetics, through a simple and painless application. Before being marketed, new drugs and medical devices must have their efficacy and safety evaluated, for which toxicity and permeation tests are recommended by regulatory authorities. Alternative methodologies to animal use have been developed for these purposes, including the chorioallantoic membrane (CAM) model of the chicken embryo. In this context, the objectives of the present study are: to test the validity of the CAM model as a method for evaluating the toxicity of topical anesthetics, comparing its findings with the results obtained in the Oral Mucosa Irritation Test; to standardize the use of the CAM as a biological barrier in in vitro permeation tests of topical anesthetics; and to develop and characterize a fast-dissolving polymeric MN system for topical dental anesthesia. Toxicity assays of topical anesthetics will be carried out using the CAM model and the Oral Mucosa Irritation Test, conducted in hamsters. Permeation studies of the topical anesthetics will also be performed, using porcine buccal mucosa and the CAM as barriers. Additionally, fast-dissolving MNs incorporated with lidocaine and epinephrine will be developed and their mechanical properties evaluated.