Development and characterization of Liquid Crystal Emulsions and Pickering emulsions for ascorbic acid

Abstract

Ascorbic acid (AA) is a potent antioxidant, capable of acting in prevention and treatment of the skin aging. However, in order to present therapeutic efficacy, AA should be kept stable and reach the active site. Although the scientific literature contains several studies using different mechanisms for the delivery of AA, the results obtained are limited and there is a shortage of publications comparing the effectiveness of systems in their delivery capacity. So, the development of stable formulations that allow viable permeation of AA in the skin remains challenging. Here, we propose the development of Liquid Crystal Emulsions and emulsions stabilized by solid particles, free of surfactants, also called Pickering emulsions for the delivery of AA. All the systems will be characterized by numerous methodologies, aiming to clarify the relationship between the physicochemical characteristics of the formulations and the release of the molecule of interest. Skin permeation tests will also be performed in order to compare the delivery effectiveness of different systems. Finally, one of the delivery systems studied will be selected to verify the effect of topical application of ascorbic acid compared to placebo using High-Frequency Ultrasound (22 and 75 MHz) in order to investigate the action of this active of epidermal thickness and dermal density and echogenicity. (AU)