Nanoemulsions (NEs) are stable nanocarrier systems consisting mainly of
oil and water, which are stabilized by surfactant with cosurfactant. Due to their typical
size, nano-emulsions are transparent or translucent, and minute droplet size makes
them stable against sedimentation or creaming. The nanoemulsion system may be in
the form of oil-in-water (O/W) or water-in-oil (W/O). The recent literature revealed
that NEs as a colloidal carrier system has been confirmed to be a valuable strategy to
improve the bioavailability of topically applied drugs. NE has been proposed as a
viable alternative to conventional topical dosage forms due to the ability to overcome
the skin/ocular barriers faced after administration. Better permeation rate, improved
therapeutic efficacy and reduction of dose, non–specific toxicity, and targeted drug
delivery system can improve drug effectiveness when drugs are incorporated into NEs.
In recent years, research studies have focused more on ion nanoemulsion systems using
a mixture of surfactants to solve critical factors, such as solubility, stability, and drug
delivery applications. This chapter outlines the recent development in nanoemulsion as
a delivery system to study topical drug delivery.