Development of a stable dermal delivery system for an anti-aging peptide

Abstract

Background: The use of topical anti-aging peptides such as glycyl-histidyl-lysine-Cu have recently been highlighted for their potential in cosmeceutical products for their beneficial properties involving skin renewal and repair. A carrier system is required for the delivery of these otherwise impermeable hydrophilic compounds as they must first pass through the skin's natural protective barrier. In response to this, vesicular carrier systems have been developed to facilitate the delivery of these bioactives to the site of action. However, these carrier systems are often complex mixtures of lipids and surfactants, and the physicochemical stability of the system is compromised when incorporated into a topical formulation such as a cosmetic cream. Therefore, strategies to stabilize these delivery systems need to be developed before such bioactive peptides may be incorporated into a topical cosmetic formulation. Aim: The aim of this thesis is to develop a vesicular delivery system, transethosomes (liposomes with edge activators and ethanol added), that can ferry an anti-aging peptide, glycyl-histidyl-lysine-Cu (GHK-Cu), to the dermis through the skin following topical application. Stability of the delivery system was optimized by the addition of a polymer, PEG and pectin, via a sterical stabilization approach. The particle size and surface charge of vesicles were investigated in relation to the ethanol content, type and amount of surfactant incorporated into the vesicles. Furthermore, the toxicity and cellular uptake of the formulations in human dermal fibroblasts was examined, and the ability of the formulation to penetrate a 3D skin tissue model was visually observed.