Retinol‐Loaded Mannosylerythritol Lipid Nanoliposome for Enhanced Human Skin Penetration

BACKGROUND: Functional cosmetic materials with anti-aging properties, such as wrinkle reduction, often struggle to penetrate the skin's stratum corneum (skin barrier). Therefore, to exert anti-aging effects, these materials must pass through the skin barrier and reach fibroblasts in the dermal layer. In this study, deformable liposomes were developed for efficient transdermal delivery of retinol, a well-known anti-wrinkle agent. MATERIALS AND METHODS: Five formulations (ML-1 to ML-5) were prepared using hydrogenated lecithin (HL) and mannosylerythritol lipid (MEL) as an edge activator with HL:MEL mass ratios of 10:0, 7:3, 5:5, 3:7, and 0:10. Their physicochemical properties, including particle size, zeta potential, polydispersity, encapsulation efficiency and deformability index were analyzed. For the optimal formulation, the liposome morphology was observed using cryo-TEM, and the retinol skin penetration ability of each liposome formulation was evaluated using a Franz diffusion cell. RESULTS: Their physicochemical properties were investigated, and ML-4 with an HL:MEL mass ratio of 3:7 was identified as the optimal formulation for transdermal delivery (particle size 89.3±6.8 nm, zeta potential -25.2±1.1 mV, polydispersity index 0.263±0.012, encapsulation efficiency 86.3±2.3%, and deformability index 5.76±1.9). Cryo-TEM analysis confirmed the liposomal morphology of ML-4. The retinol skin penetration ability of each formulation was evaluated using the Franz diffusion cell, with the conventional liposome (ML-1) without MEL as the control. The ML-4 formulation achieved a total retinol penetration of 29.0%, a 10.6% increase compared to ML-1 (18.4%). CONCLUSIONS: In this study, the ML-4 deformable liposome formulation, using MEL as an edge activator, efficiently encapsulates retinol, a wrinkle improvement agent, and improves skin penetration without causing physical damage. These findings suggest that ML-4 can serve as an efficient transdermal delivery system for functional cosmetic materials.