After the initial screening, one liquid lipid with low solubilization capacity and one with good solubilization capacity with BTB were selected. A solid excipient, cetyl palmitate (CP), was chosen to simulate the preparation of an NLC preformulation. The two chosen liquid lipids were heated 10 ºC above the melting point of cetyl palmitate, separately. Butamben was then added to the liquid lipid, under stirring, until a visually homogeneous mixture was obtained, or by five minutes in case of low solubility.