Fig. 3. Binary diagram noting the concentrations of purified poloxamer 188 and the cosurfactant fatty acids necessary to form propofol microemulsions in a bulk media of normal saline. The concentration of propofol was constant at 10 mg/ml. For a given fatty acid cosurfactant, the  region below the line is a microemulsion, whereas the  area above the line represents a macroemulsion formulation.