Nanostructured lipid carriers as vehicles for transdermal iontophoretic drug delivery

The aim of the present work was to assess the merits of nanostructured lipid carriers (NLCs) as vehicles for transdermal iontophoretic drug delivery. For the measurements, either a model drug (triamcinolone acetonide acetate, TAA) or a lipophilc fluorescent probe (nile red, NR) was encapsulated into NLCs. The NLCs with sizes of 100 nm and 350 nm diameter were prepared by high-pressure homogenization technique. The particle size with polydispersity index (PDI), zeta potential and morphology were examined by photon correlation spectroscopy (PCS) and atomic force microscopy (AFM). In vitro penetration studies involved passive penetration and iontophoresis for control (TAA ethanol solution) and TAA-NLCs formulations. Confocal laser scanning microscopy (CLSM) was employed to visualize the distribution of NR-NLCs after skin permeation. The overall results reveal the benefits of the combined use of iontophoresis and NLCs in improving skin penetration parameters. The NLCs with a size of 100 nm seem to be promising for iontophoretic delivery as they have shown maximum enhancement ratio and skin deposition. This is the first report of the use of NLCs as vehicles for transdermal iontophoretic drug delivery.