Melatonin loaded ethanolic liposomes: Physicochemical characterization and enhanced transdermal delivery

The current investigation aims to evaluate the transdermal potential of novel ethanolic liposomes (ethosomes) bearing Melatonin (MT), an anti-jet tag agent associated with poor skin permeation and long lag time. NIT loaded ethosomes were prepared and characterized for vesicular shape and surface morphology, vesicular size, entrapment efficiency, stability, in vitro skin permeation and in vivo skin tolerability. Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and Dynamic Light Scattering (DLS) defined ethosomes as spherical, unilamellar structures having low polydispersity (0.032 +/- 0.011) and nanometric size range (122 +/- 3.5 nm). % Entrapment efficiency of MT in ethosomal carrier was found to be 70.71 +/- 1.4. Stability profile of prepared system assessed for 120 days revealed very low aggregation and growth in vesicular size (7.6 +/- 1.2%). MT loaded ethosomal carriers also provided an enhanced transdermal flux of 59.2 +/- 1.22 mu g/cm(2)/h and decreased lag time of 0.9 h across human cadaver skin. Fourier Transform-Infrared (FT-IR) data generated to assess the fluidity of skin lipids after application of formulation revealed a greater mobility of skin lipids on application of ethosomes as compared to that of ethanol or plain liposomes. Skin permeation profile of the developed formulation further assessed by confocal laser scanning microscopy (CLSM) revealed an enhanced permeation of Rhodamine Red (RR) loaded formulations to the deeper layers of the skin (240 pm). Further, a better skin tolerability of ethosomal suspension on rabbit skin suggested that ethosomes may offer a suitable approach for transdermal delivery of melatonin. (c) 2007 Elsevier B.V. All rights reserved.