*2.1.3 Microfluidization*

Microfluidization is the most widely employed and novel technique in the pharmaceutical and cosmetic industry in order to acquire fine emulsions [18]. High pressure is provided by device called Microfluidizers (MF). Initially a coarse emulsion is made using a high speed mixer which is then fed into the hood and accelerated at high velocities within the channels using a pumping device and the macroemulsion to go through the interaction chamber by the high pressure forces and thus nanoemulsions with submicron ranged particles are produced [17]. The channels are made to collide into each other within the interaction chamber [21]. Uniform nanoemulsion can be produced by repeating the process many times and vary the operating pressure to get desired particle size [18].

The main parts of a MF include a fluid inlet (where the coarse emulsion is fed), a pumping device (to help move the emulsion through), and the interaction chamber or nozzle (where the particle collision occurs) [22]. A collision between crude emulsion jets from two opposite channels in the nozzle of microfluidizers is observed. The mobility of crude emulsion is supplied by a pneumatically powered pump that has capability of compressing air up to pressures between 150 and 650 MPa [18]. This high pressure forces the crude emulsion stream to go through microchannels and after the collision of two opposite channels enormous level of shearing force is produced. Hence, by the help of this force fine emulsions are produced [23] (**Figure 3**).

**71**

*2.2.2 Phase inversion*

*An Update on Nanoemulsions Using Nanosized Liquid in Liquid Colloidal Systems*

Requiring no expensive equipment, easier implementation and better efficiency in

[16, 17, 24, 25]. Moreover, encapsulation of drugs and macromolecules can be carried out due to mild operating temperatures. The necessity for higher amounts of surfactants may be a downside [17]. The whole concept of low energy synthesis has its roots in modification of factors responsible for the hydrophilic–lipophilic balance of the surfactantoil–water mixture [26]. These include environmental factors like temperature, composition and the chemical potential of the components. Spontaneous Emulsification (SE)

An emulsion can be fabricated by diluting a biphasic system leading to diffusion of one phase to another. This is usually done by adding the organic phase into the aqueous phase and then a surfactant which is water miscible. The migration of the surfactant causes disorder at the interface of the two phases leading to an increase in the surface area along with the formation of oil droplets in the aqueous phase [16]. To obtain nanoemulsions, the same dilution process is performed on microemulsions. The properties of the nanoemulsion depend on the oil viscosity, surfactant hydrophilic–lipophilic balance and solvent miscibility with water. With the help of an appropriate dilution procedure and composition, both W/O and O/W microemulsions can be used to obtain nanoemulsion. While obtaining it from O/W microemulsion the composition of microemulsion and the procedure of dilution does not matter, whereas while starting with W/O microemulsion the dilution procedure and /or the composition of microemulsion matters. O/W and W/O nanoemulsions can be formed even without a surfactant, this is called the Ouzo effect also known as Solvent displacement method [24, 27, 28]. This phenomenon has mainly been used for fabricating polymeric nanoparticles or nanocapsules using

As addressed earlier, there are different types of Nanoemulsions, either oil in water (O/W) or water in oil (W/O). Phase inversion, as the name suggests, is a fabrication method that involves conversion of O/W to W/O emulsion or vice versa. It utilizes the energy released during this conversion for the formation of droplets. This physical process can be brought about by varying the temperature or phase

terms of energy are the reasons for the growing interest in low energy methods

and Phase Inversion are two commonly implemented synthesis [17, 24].

*DOI: http://dx.doi.org/10.5772/intechopen.84442*

**2.2 Low energy methods**

*Schematic representation of microfluidizer [23].*

**Figure 3.**

*2.2.1 Spontaneous emulsification*

nanoemulsion as a template in drug delivery [25].

*An Update on Nanoemulsions Using Nanosized Liquid in Liquid Colloidal Systems DOI: http://dx.doi.org/10.5772/intechopen.84442*

#### **Figure 3.**

*Nanoemulsions - Properties, Fabrications and Applications*

*Schematic representation of ultrasonic jet homogenizer [23].*

of a single sound wave [23]. By this enormous levels of highly localized turbulence is generated and it causes micro implosions which disrupt large droplets into sub-micron size. Since most of the ultrasonic systems emits sound field which are inhomogeneous, so in order to have droplets to experience highest shear rate, recirculation of the emulsion through the region of high power must be provided and on repeating recirculation we obtain uniform droplet size at dilute concentration [18]. Presently sonication has been well established for the laboratory scale but it may be difficult to implement on a production scale because of issues like low throughput. Optimization of parameters (like emulsifier type, amount emulsifier and viscosity of phases) is necessary to prepare nanoemulsions having fine droplets [18]. Even, the high local intensity provided by sonication could lead to detrimental quality effects by way of protein denaturation, polysaccharide polymerization or

Microfluidization is the most widely employed and novel technique in the pharmaceutical and cosmetic industry in order to acquire fine emulsions [18]. High pressure is provided by device called Microfluidizers (MF). Initially a coarse emulsion is made using a high speed mixer which is then fed into the hood and accelerated at high velocities within the channels using a pumping device and the macroemulsion to go through the interaction chamber by the high pressure forces and thus nanoemulsions with submicron ranged particles are produced [17]. The channels are made to collide into each other within the interaction chamber [21]. Uniform nanoemulsion can be produced by repeating the process many times and vary the operating pressure to get desired particle

The main parts of a MF include a fluid inlet (where the coarse emulsion is fed), a pumping device (to help move the emulsion through), and the interaction chamber or nozzle (where the particle collision occurs) [22]. A collision between crude emulsion jets from two opposite channels in the nozzle of microfluidizers is observed. The mobility of crude emulsion is supplied by a pneumatically powered pump that has capability of compressing air up to pressures between 150 and 650 MPa [18]. This high pressure forces the crude emulsion stream to go through microchannels and after the collision of two opposite channels enormous level of shearing force is produced.

Hence, by the help of this force fine emulsions are produced [23] (**Figure 3**).

lipid oxidation of the emulsion components [23] (**Figure 2**).

*2.1.3 Microfluidization*

**Figure 2.**

**70**

size [18].

*Schematic representation of microfluidizer [23].*

#### **2.2 Low energy methods**

Requiring no expensive equipment, easier implementation and better efficiency in terms of energy are the reasons for the growing interest in low energy methods [16, 17, 24, 25]. Moreover, encapsulation of drugs and macromolecules can be carried out due to mild operating temperatures. The necessity for higher amounts of surfactants may be a downside [17]. The whole concept of low energy synthesis has its roots in modification of factors responsible for the hydrophilic–lipophilic balance of the surfactantoil–water mixture [26]. These include environmental factors like temperature, composition and the chemical potential of the components. Spontaneous Emulsification (SE) and Phase Inversion are two commonly implemented synthesis [17, 24].
