pharmaceutics Review Self-Nano-Emulsifying Drug-Delivery Systems: From the Development to the Current Applications and Challenges in Oral Drug Delivery Aristote B. Buya 1,2 , Ana Beloqui 1, Patrick B. Memvanga 2 and Véronique Préat 1,* 1 Advanced Drug Delivery and Biomaterials, Louvain Drug Research Institute, Université Catholique de Louvain, Avenue Mounier 73, B1.73.12, 1200 Brussels, Belgium;
[email protected] (A.B.B.);
[email protected] (A.B.) 2 Pharmaceutics and Phytopharmaceutical Drug Development Research Group, Faculty of Pharmaceutical Sciences, University of Kinshasa, Kinshasa XI BP 212, Democratic Republic of the Congo;
[email protected] * Correspondence:
[email protected]; Tel.: +32-27647309 Received: 3 November 2020; Accepted: 5 December 2020; Published: 9 December 2020 Abstract: Approximately one third of newly discovered drug molecules show insufficient water solubility and therefore low oral bio-availability. Self-nano-emulsifying drug-delivery systems (SNEDDSs) are one of the emerging strategies developed to tackle the issues associated with their oral delivery. SNEDDSs are composed of an oil phase, surfactant, and cosurfactant or cosolvent. SNEDDSs characteristics, their ability to dissolve a drug, and in vivo considerations are determinant factors in the choice of SNEDDSs excipients. A SNEDDS formulation can be optimized through phase diagram approach or statistical design of experiments. The characterization of SNEDDSs includes multiple orthogonal methods required to fully control SNEDDS manufacture, stability, and biological fate. Encapsulating a drug in SNEDDSs can lead to increased solubilization, stability in the gastro-intestinal tract, and absorption, resulting in enhanced bio-availability. The transformation of liquid SNEDDSs into solid dosage forms has been shown to increase the stability and patient compliance.