Fig. 2. Pseudoternary diagram of an oil-in-water propofol microemulsion of propofol (oil), purified poloxamer 188 (nonionic surfactant), and sodium caprylate (ionic cosurfactant; C8fatty acid salt) (the diagram is defined as pseudoternary, vis-à-vis ternary, because the fourth component of the microemulsion system is the bulk media, 0.9% wt/vol NaCl in water, and is not plotted, but did not change throughout the studies). The regions of the phase diagram below and above the dashed line represent microemulsion and macroemulsion regions, respectively. As is typical of these diagrams, the axes are normalized with values representing a fraction of the maximal concentration of components used (propofol: 100 mg/ml; purified poloxamer 188: 70 mg/ml; sodium caprylate: 12.5 mg/ml) and are, therefore, without units of measure.