Nanoemulsions are composed of nanoscale droplets of one immiscible liquid dispersed within another, which have been the
focus of extensive research worldwide due to their solubilization and transportation capacity of both hydrophobic and hydrophilic active
compounds with unique physical properties. In a broad sense, submicron-emulsion, microemulsion, self-microemulsifing drug delivery
system, lipid emulsion and cholesterol-rich microemulsion (LDE) all belong to nanoemulsions. The review starts with a brief introduction
to the definition, formulation rationale, and types of nanoemulaions, and focused on, by different administration routes such as the
oral, intravenous, transdermal, ocular nasal and rectal routes, the absorption, disposition, pharmacokinetics properties of nanoemulsions.