Abstract
The human skin, considered as the main barrier from the outside, is more and more assaulted by environmental sources (UV, pollutants, tobacco…). These aggressions over generate free radicals within the skin then leading to skin aging and potentially skin cancer. Therefore, nanoformulations based on polyoxazolines for topical delivery of antioxidants were investigated in order to quench the excess of free radicals located in the epidermis. As a side objective, this research project intends to demonstrate the potential of amphiphilic polyoxazolines in formulation as an alternative to poly(ethylene glycol), which overuse has led to clinical awareness. Various macromolecular architectures of polyoxazolines were synthesized and two main nanoformulations were elaborated: mixed micelles and lipid nanocapsules. These last showed a high stability overtime, a good drug loading and maintained the antioxidant activity of the encapsulated quercetin. The skin penetration study of polyoxazolines and polyoxazolines based formulations was conducted on various skin models (GUV, nonbiological skin model, mice ears, human skin explants). Nanoformulations were able to modify physicochemical skin surface properties to enhance their spreading and polyoxazolines penetrated from simple to complex lipids membranes and in vivo in mice skin. As a conclusion, polyoxazolines were proved to be an excellent alternative to poly(ethylene glycol) overuse for designing formulations and show promise for delivering topically antioxidants into epidermis creating new possibilities for skin treatment such as psoriasis or melanomas.