Supplemental file1
Effects of glycerol concentrations
The choice of the concentration of the studied binary mixture of glycerol (58.5% w:w) results from preliminary tests performed with the following concentrations: 24, 46.75, 58.5 and 80% (w:w). The main results of these tests are reported below.
Instantaneous surface tension
Surface tension was measured as described in the paper immediately after contact between the aqueoussolution containing the surfactants and ambient air. We observed (Figure 1S) that the results can be schematically divided in two groups: those of pure water, 24% and 46.75% of glycerol on the one side and those of glycerol at 58.5 and 80% on the other side.
Figure 1S. Surface tension of the aqueous media containing the surfactants, measured via the pendant drop method, immediately after drop formation. The Tween80/Span80 ratio is kept constant and the instantaneous surface tension is plotted as a function of the tween 80 concentration.
Observation of self-emulsification through the SEDDS phase
The self-emulsification of the SEDDS formulation upon contact with glycerol solutions was observed via the SEDDS phase for various glycerol concentrations. The experiments were conducted as described in the manuscript for pure water and 58.5% of glycerol. We additionally report in the Figure 2S the results obtained with 24, 46.75, and 80% w:w of glycerol in the aqueous phase. For pure water and 24% of glycerol the behaviour are very similar. The interfacial tension allows the drop to be maintained at the syringe tip and after some minutes a“hairy” phase develops around the droplet. In contrast, for 58.5 % and 80% of glycerol, no drop could be formed. For 46.75% of glycerol, a drop can be formed but the hairy phase does not appear. Instead a grey cloud forms which seems to indicate the presence of an emulsion.
Figure 2S.Observation of self-emulsification trough the SEDDS phase for various aqueous media. From top to bottom, the glycerol concentration is 0, 24, 46.75, 58.5 and 80%. All scale bars represent 500µm.
Observation of self-emulsification through the aqueous phase
The results are gathered in Figure 3S. The method is the same as the one followed in the manuscript.
Figure 3S. Temporal evolution of SEDDS injected into the aqueous media. The scale bars represent 500 µm.
Droplet size distribution
Droplet size distributions have been measured following the protocol described in the manuscript for emulsions obtained with various glycerol concentrations. The results are displayed in Figure 4S where we can observe that for pure water, 24 and 46 %, the maximum of the distribution is found for approximately 200µm while a further increase of the glycerol concentration shifts this value toward smaller sizes.
Figure 4S.Droplet Size Distributions of the oil in water emulsions obtained for various concentrations of the aqueous phase.