Miglyol 812n

The LDE-paclitaxel oleate preparation was made according to the methods described in
previous studies (11 (link),27 (link),28 (link)). Briefly, a lipid
mixture composed by 135 mg cholesteryl oleate (Alfa Aesar, USA), 333 mg egg
phosphatidylcholine (Lipoid, Germany), 132 mg miglyol 812N (Sasol Germany GmbH,
Germany), 6 mg cholesterol (Fabrichem, USA) and 60 mg of paclitaxel oleate
(Pharmaceuticals Co., China), was added to an aqueous phase consisting of 100 mg of
polysorbate 80 (Merck, Germany) and 10 mL Tris-HCl buffer, pH 8.05. A pre-emulsion
was obtained by ultrasonic radiation until complete solubilization of the drug.
Emulsification of all lipids, drug and aqueous phase was obtained by high-pressure
homogenization using an Emulsiflex C5 homogenizer (Avestin, Canada). After
homogenization cycles, the formed emulsion was centrifuged and the nanoparticle
sterilized by passage through 0.22 μm pore polycarbonate filter (Millipore, USA) and
kept at 4°C until used.

The chitosan-coated nanocapsules were prepared as previously described with modifications [17 ,19 ]. Briefly, for the in vitro experiments, 400 μl of a 100 mg/ml ethanolic lecithin solution (Epikuron 145 V, Cargill texturing solutions Deutschland GmbH &Co. KG, Hamburg, Germany) was mixed with 530 μl of the capsaicin stock solution (24 mg/ml). This was supplemented with 125 μl Miglyol 812 N (Sasol GmbH, Witten, Germany) and 9.5 ml ethanol. The organic solution was immediately poured into 20 ml chitosan in the aqueous phase (0.5 mg/ml in 5% stoichiometric excess of HCl). The milky mixture was concentrated in a rotavapor (Büchi R-210, Büchi Labortechnik GmbH, Essen, Germany) at 50°C until 3.5–4.0 ml remained and the volume was topped up to 4.0 ml with milliQ water if necessary to yield a final capsaicin concentration of ~10 mM. The nanoemulsions were prepared using the same procedure but without including chitosan. Unloaded nanocapsules and nanoemulsions were prepared by replacing the capsaicin solution with ethanol. The physical characteristics of the nanocapsules have been documented in a previous study [17 ]. Briefly, the size of the formulations was around 200 nm, the zeta potential was highly positive (~ +60 mV) and the polydispersity index had a value of ~ 0.2. These values were obtained by dynamic light scattering.