Polarity-induced intermolecular association of ceramide liposomes for enhanced skin delivery

Herein, we report on a polarity-induced ceramide liposome system (PICL) that can inhibit the ceramide recrystallization and enhance the skin delivery of active materials. This is likely due to the synergistic effects of oleic acid, ceramide, and lecithin, which disrupt the stratum corneum lipid structure, increase membrane fluidity, and promote permeability. To achieve this, we fabricated a system consisting of ceramide and oleic acid, where thermotropic phase transitions induced by temperature variations imparted partial charges to ceramides, thereby enhancing polarity-induced intermolecular association with oleic acid. We demonstrated excellent long-term stability, maintaining their structure without ceramide recrystallization even under harsh conditions like high temperatures. In vitro skin penetration studies confirmed that PICL effectively interacted with the stratum corneum, thereby enhancing skin permeability. Based on the superior skin permeability of PICL, both in vitro and clinical studies further demonstrated significantly improved delivery of active materials into the skin. Moreover, clinical efficacy tests of active material-encapsulated PICLs showed effectiveness in improving skin brightening and reducing the depth of periorbital wrinkles. Therefore, our PICL, with a robust molecular layer, offers various applications in a wide range of fields, including dermatology and functional cosmetics.