**11. Conclusion**

For many drugs with poor aqueous solubility, the technique of developing SMEDDS/SNEDDS provides a powerful and effective solution to improve their solubility in the aqueous contents of the GI tract that is the main obstacle for such drugs. The most critical step in designing the nanoformulations of lipid‐based systems for PWSDs is the selection of the most suitable oil, surfactant and/or cosolvent for a particular drug with certain physicochemical properties. So, the formulators must keep a balance and make compatibility between the factors of different formulations such as self‐emulsification efficiency, drug loading capacity, droplet size distri‐ bution, *in vitro* dispersion/release profile in acidic and basic media and *in vitro* digestion by using fed and fasted state. In summary, SMEDDS/SNEDDS provide a robust formulation approach to enhance GI solubilization and to promote drug absorption after oral administra‐ tion. If there is a successful *IVIVC* made for lipid nanoformulations, confidence in the devel‐ opment of the pharmaceutical product and its quality are likely to improve, and the drug development time may be shortened.
