Around 0.10 to 0.20 g of BTB was weighed and transferred to a becker, then the liquid excipient was added until BTB complete solubilization (indicated by the transparence of the solution). Solid excipients were first melted (10ºC above their melting points), and added to the BTB until complete solubilization, under stirring. In this case, the solubility of BTB was shifted to higher values, because it was measured at higher temperatures than with the lipid liquids .