Emulsions are liquid-liquid dispersions with one liquid phase dispersed in the other liquid phase as small droplets. Nanoemulsions are nano-sized emulsions with sizes ranging from tens to hundreds of nanometers, and have great potential applications in pharmaceutics, foods and cosmetics due to their attractive properties, such as small sizes, high surface area per unit volume, improved dispersion of active hydrophobic components and enhanced absorption. The article provides an overview of nanoemulsions for drug delivery, starting with an introduction of emulsion types, nanoemulsion preparation and nanoemulsion stability. Surfactants play critical roles in producing and stabilizing nanoemulsions. Different types of surfactants are summarized including small molecule surfactants, particle surfactants, phospholipids, peptide and protein surfactants. Then the applications of nanoemulsions as nanomedicine in drug delivery are presented. Finally, clinical applications of nanoemulsions are discussed.

乳液是一种液-液分散体，一种液相以小液滴的形式分散在另一种液相中。纳米乳液是纳米级乳液，粒径从几十纳米到几百纳米不等，由于具有粒径小、单位体积比表面积大、活性疏水的分散性提高等吸引人的特性，在医药、食品和化妆品等领域具有巨大的应用潜力。 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?成分和增强吸收。文章概述了用于药物递送的纳米乳剂，首先介绍了乳剂类型、纳米乳剂制备和纳米乳剂稳定性。表面活性剂在生产和稳定纳米乳液方面起着关键作用。总结了不同类型的表面活性剂，包括小分子表面活性剂、颗粒表面活性剂、磷脂、肽和蛋白质表面活性剂。然后介绍了纳米乳作为纳米药物在药物递送中的应用。最后，讨论了纳米乳剂的临床应用。