The characteristics and biological activity enhancements of melatonin encapsulations for skin care product applications

Melatonin (MLT) exhibits antioxidant, ultraviolet protection, anti-inflammatory, and anti-aging properties. However, its effectiveness is limited by instability, a short half-life, and incompatible absorption. In this research, we encapsulated melatonin (MLT) in transfersomes (MT) and niosomes (MN) to enhance their properties and investigate their effects through in vitro cell assays using murine macrophages cells and human foreskin fibroblasts cells. The vesicle morphology, vesicle size, polydispersity index, zeta potential, entrapment efficiency (EE%), attenuated total reflectance-Fourier transform spectroscopy (ATR-FTIR) spectra, along with in vitro release, permeation profiles, and stability study were also evaluated. The results showed that both encapsulations displayed spherical morphology at the nanometric scale, their great physical stability and provided an EE% range of 58-78%. The MLT incorporation into the vesicle was confirmed by the ATR-FTIR spectra. Additionally, the encapsulation' release profiles fitted with the Higuchi model, indicating controlled release of melatonin. Furthermore, MT showed greater permeability than MN and MS including melatonin deposition. In cell assays, MT exhibited significantly higher nitric oxide inhibition and stimulation of collagen compared to MN and MS. Therefore, MT demonstrated the highest possibility for anti-inflammatory and collagen-stimulating activities that could be applied in pharmaceutical or anti-aging cosmetic products.