Techniques for Formulation of Nanoemulsion Drug Delivery System: A Review

Abstract

Nanoemulsion drug delivery systems are advanced modes for delivering and improving the bioavailability of hydrophobic drugs and the drug which have high first pass metabolism. The nanoemulsion can be prepared by both high energy and low energy methods. High energy method includes high-pressure homogenization, microfluidization, and ultrasonication whereas low energy methods include the phase inversion emulsification method and the self-nanoemulsification method. Low energy methods should be preferred over high energy methods as these methods require less energy, so are more efficient and do not require any sophisticated instruments. However high energy methods are more favorable for food grade emulsion as they require lower quantities of surfactant than low energy methods. Techniques for formulation of nanoemulsion drug delivery system are overlapping in nature, especially in the case of low energy methods. In this review, we have classified different methods for formulation of nanoemulsion systems based on energy requirements, nature of phase inversion, and self-emulsification.

Keywords: drug delivery; high energy method; low energy method; nanoemulsion; phase inversion methods.

Fig. 1

High-pressure homogenization techniques (Wang, 2014).

Fig. 2

Microfluidization techniques (Singh et al., 2017).

Fig. 3

Ultrasonication techniques (Singh et al., 2017).

Fig. 4

Phase inversion emulsification techniques (Solans and Solé, 2012). PIC, phase inversion composition; PIT, phase inversion temperature; EIP, emulsion inversion point; O/W, oil-in-water emulsion; W/O, water-in-oil emulsion.

Fig. 5

Self-nanoemulsification techniques (Alshamsan et al., 2018). SNEDDS, self-nanoemulsifying drug delivery system; GIT, gastrointestinal tract.