Characterization of copper tripeptide-loaded lipid carriers and their stability in complex cosmetic matrices.

GHK-Cu is a tripeptide-copper complex composed of glycine-L-histidine-L-lysine coordinated with Cu²⁺ ions. Owing to its regenerative and antiaging properties, it is widely incorporated as an active ingredient in cosmetic formulations. Nevertheless, its pronounced hydrophilicity limits its ability to penetrate deeper layers of the skin. One potential strategy to overcome this limitation is the application of liposomal carriers. Encapsulating the GHK-Cu complex in liposomes may enhance its transdermal delivery efficiency while reducing the effective concentration of the copper tripeptide in the final formulation, thereby lowering production costs. The objective of the present study was to evaluate the stability of liposome-encapsulated GHK-Cu in cosmetic products, specifically in oil-in-water emulsion and serum formulations containing various ingredients, using the electromigration separation technique coupled to ICP mass spectrometry. Liposomes containing the GHK-Cu complex were prepared and subsequently incorporated into model cosmetic products. The stability of the liposome-GHK-Cu system within these formulations was investigated using capillary electrophoresis coupled with inductively coupled plasma tandem mass spectrometry (CE-ICP-MS/MS). Capillary electrophoresis enabled the separation of individual species in the samples, whereas ICP-MS/MS provided selective detection of copper ions from the GHK-Cu complex and of phosphorus, used as a liposomal marker. The use of tandem mass spectrometry was essential to minimize spectral interferences during phosphorus determination.