Nanoemulsions (NEs) are emulsions with particle size of less than around 100 nm. Reviewing the literature, several reports are available on NEs, including preparation, characterization, and applications of them. This review aims to brief challenges that researchers or formulators may encounter when working with NEs. For instance, when selecting NE components and identifying their concentrations, stability and safety of the preparation should be evaluated. When preparing an NE, issues over scale-up of the preparation as well as possible effects of the preparation process on the active ingredient need to be considered. When characterizing the NEs, the two major concerns are accuracy of the method and accessibility of the characterizing instrument. Also a highly efficient NE for clinical use to deliver the active ingredient to the target tissue with maximum safety profile is commonly sought. Throughout the review we also have tried to suggest approaches to overcome the challenges.

中文翻译：

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当前纳米乳剂的制备、表征和制药应用面临的挑战

纳米乳液 (NE) 是粒径小于 100 nm 左右的乳液。回顾文献，有几篇关于NE的报告，包括它们的制备、表征和应用。本综述旨在简要介绍研究人员或配方设计师在使用 NE 时可能遇到的挑战。例如，在选择NE成分并确定其浓度时，应评估制剂的稳定性和安全性。在制备NE时，需要考虑制备放大的问题以及制备过程对活性成分可能产生的影响。在表征 NE 时，两个主要问题是方法的准确性和表征仪器的可访问性。人们还普遍寻求一种用于临床的高效 NE，以最大安全性将活性成分递送至靶组织。在整个审查过程中，我们还尝试提出克服挑战的方法。