**7. Phase diagram of lipid formulations**

The phase diagram in SNEF is constructed to choose a right potential candidate of oil, surfactant, and co-surfactant which is selected by varying concentration of surfactant, oil, and solubilizers depending on physiochemical properties of API such as surface activity and polarity. Orange colored area of self good self emulsification are established by diluting the mixture of oil and surfactant sequentially phase studies are performed by an increase in the amount of water (**Figure 2**). Once equilibrium is achieved types of phases recognized by using an optical microscope or cross-polarized viewer [24, 25].

#### **Figure 2.**

*Schematic ternary phase diagram of SNDDS system.*
