Copper tripeptide (GHK-Cu) is a well-known cosmetically active compound, naturally occurring in human plasma, that exhibits multiple beneficial properties, including antiaging effects [1]. However, due to its physicochemical properties, GHK-Cu has difficulty passing through epidermal cells, which reduces its efficacy. The limited delivery of cosmetically active compounds into deeper skin layers remains one of the main challenges for the cosmetics industry, which constantly strives to enhance product effectiveness. A promising solution could be the use of liposomes as carriers. These biocompatible, non-toxic structures with morphology similar to living cell membranes can encapsulate active compounds and release them in a controlled manner [2]. Liposome‒GHK-Cu systems obtained by ethanol injection method are being investigated for their potential as GHK-Cu carriers. Studies under conditions simulating transport through the skin layers have been conducted to evaluate the transport efficiency of the described systems from simple cosmetic formulations into the skin. The research examines the influence of time, the lipid composition of the carriers, and the effect of the purification process of the liposomal suspension on the skin permeation of GHK-Cu encapsulated in liposomes. Diffusion cells and a synthetic model imitating human skin were used for this purpose. The skin permeation of both antiaging GHK-Cu encapsulated in liposomes and free GHK-Cu was measured using ICP-MS/MS-based techniques.

Capillary electrophoresis combined with inductively coupled plasma tandem mass spectrometry (CE-ICP-MS/MS) was used to verify the encapsulation process and stability of the liposome-based systems in cosmetics by monitoring the ⁶³Cu⁺ (GHK-Cu marker) and ³¹P¹⁶O⁺ (liposome marker) signals. This modern technique enables the analysis of cosmetic products containing liposomal systems without using organic solvents, which could interfere with liposome morphology.