Nanoemulsion: Synthesis, Characterization and Its Applications

Nanoemulsions (NEs), an isotropic mixture of oil and water stabilised by FDA approved surfactant and co-surfactant molecules have mean droplet size less than 25% of wavelength of visible light. They are homogenous, optically clear solution with high free energy, drug penetration, bio-availability, absorption rate, resistant to enzymatic degradation and hydrolysis can store both hydrophilic and lipophilic drugs depending on the type of NE formed which results in enhanced physicochemical properties and behavioural kinetics than micro/macro emulsions. They utilise only less amount of surfactant and reduce the dosage and frequency of drug. NEs can be prepared by both high energy and low energy emulsification method where former make use of devices to create dispersive forces while the latter makes use of change in parameters that affect the hydrophilic-lipophilic balance (HLB) of the system. Their thermodynamic and physical stability, Critical Micelle Concentration (CMC), Interfacial tension, viscosity, Particle size, electrical conductivity, pH, Scanning Electron Microscopy and Transmission Electron Microscopy are analyzed to make desired NEs that suit a particular application. Nanoemulsion region is determined by construction of Ternary phase diagram. Use of co-surfactant follows Pseudo-Ternary Phase diagram. NEs are used in wide range of applications like antimicrobial, cosmetics, cancer therapy, anti-inflammation, oil recovery, skin permeation etc. Basic researches have to be done to lead to the next level in making many NE formulations to meet human needs of today's world in all possible ways.