In this study, we conducted a clinical evaluation of brightening efficacy of cosmetic formulation containing cationic liposome as a skin delivery system. Our previous studies showed that liposomes have different skin penetration capabilities depending on surface charge. Among cationic, anionic, and neutral ion liposomes, cationic liposomes exhibited the best skin permeability. In addition, in the 3d-skin model with melanocytes, cationic liposome clearly attenuated melanin formation and transfer. This is because electrostatic attraction occurs between the cationic liposomes and the negatively charged skin surface, the skin penetration of cationic liposomes was enhanced. However, since there was a limitation in in vitro research. Therefore, the main objective of this study was to determine the clinical efficacy of cationic liposome application of human face.
The clinical evaluation was conducted for 4 weeks with 21 female subjects. Test sample A and B with niacinamide 2% respectively, were formulated in the essence. Sample A directly added niacinamide to the essence, and sample B applied cationic liposomes containing niacinamide to the essence. The clinical outcomes were evaluated by measuring skin brightness (L-value), melanin index, and skin melasma (affected areas, mm²). As a results, the sample B showed significant improvements like increased skin brightness, decreased melanin index and skin melasma compared to the sample A. Sample B showed about 1.5 times better brightening effects for the above three evaluation categories after 4 weeks compared to Sample A.
This clinical study demonstrated the efficacy of cationic liposome on skin brightening effect in cosmetic formulation. Because cationic liposomes enhanced skin absorption of active ingredients, active ingredients performed effectively in human skin. Thus, cationic liposome can be a effective delivery system of active ingredients that enhance skin efficacy.