In this paper, the preparation and characterization of some novel nanostructured lipid
carriers for drug delivery are reported. They are obtained by mixing two solid lipids, cetyl
palmitate and glyceryl stearate, with three types of vegetable oils: grape seed oil, St. John’s
wort oil (Hypericum perforatum oil) and sea buckthorn oil. In order to increase their
antioxidant and antimicrobial properties, they are co-loaded with green tea extract by
using a modified high shear homogenization technique. Size distribution and poly-
dispersity index of the developed nanostructured lipid carriers determined by the dynamic
light scattering, and corroborated with the results obtained by the transmission electron
microscopy analysis, confirmed that the structures obtained are at nanoscales. The
crystallinity behavior of the prepared nanostructured lipid carriers has been studied by
differential scanning calorimetry; zeta potential measurements show that all loaded
nanostructures present excellent physical stability. Their antioxidant and antimicrobial
properties evaluated by an appropriate in vitro analysis using the chemiluminescence
method, and the diffusion disc method, respectively, show that green tea extract could be
utilized as a valuable natural source of antioxidant and antimicrobial agent. These new
nano-formulations proved to have significant potential for nutritional and pharmaceutical
applications.