A miniemulsion (also known as nanoemulsion) is a particular type of emulsion. A miniemulsion is obtained by ultrasonicating a mixture comprising two immiscible liquid phases (for example, oil and water), one or more surfactants and, possibly, one or more co-surfactants (typical examples are hexadecane or cetyl alcohol). They usually have nanodroplets with uniform size distribution (20–500 nm) and are also known as sub-micron, mini-, and ultra-fine grain emulsions. [1]
Mini-emulsion: emulsion in which the particles of the dispersed phase have diameters in the range from approximately 50 nm to 1 μm.
Note 1: Mini-emulsions are usually stabilized against diffusion degradation (Ostwald ripening (ref. [6] )) by a compound insoluble in the continuous phase.
Note 2: The dispersed phase contains mixed stabilizers, e.g., an ionic surfactant, such as sodium dodecyl sulfate (n-dodecyl sulfate sodium) and a short aliphatic chain alcohol ("co-surfactant") for colloidal stability, or a water-insoluble compound, such as a hydrocarbon ("co-stabilizer" frequently and improperly called a "co-surfactant") limiting diffusion degradation. Mini-emulsions are usually stable for at least several days. [7]
Mini-emulsion polymerization: Polymerization of a mini-emulsion of monomer in which all of the polymerization occurs within preexisting monomer particles without the formation of new particles. [8]
There are two general types of methods for preparing miniemulsions:
Miniemulsions are kinetically stable but thermodynamically unstable. [13] Oil and water are incompatible in nature, and the interface between them is not favored. Therefore, given a sufficient amount of time, the oil and water in miniemulsions separate again. Various mechanisms such as gravitational separation, flocculation, coalescence, and Ostwald ripening result in instability. [14] In an ideal miniemulsion system, coalescence and Ostwald ripening are suppressed thanks to the presence of the surfactant and co-surfactant. [9] With the addition of surfactants, stable droplets are then obtained, which have typically a size between 50 and 500 nm. [15] [16]
A sterile filter is a device used to remove microorganisms and other contaminants from a liquid or gas, making it sterile. [17] [18] Sterile filters are commonly used in the medical, pharmaceutical, and biotech industries to ensure that the products produced are free of bacteria and other harmful organisms.
There are different types of filters which include:
A nanogenizer, also known as a high-pressure homogenizer or a microfluidizer, is a device used to create small droplets or particles by applying high pressure to a liquid mixture. [24] These devices can be used to produce nanoemulsions, as well as other types of emulsions and suspensions. [25] They work by passing the mixture through a small orifice under high pressure, which causes the liquid to be sheared and broken into small droplets or particles. The size of the droplets or particles can be controlled by adjusting the pressure and the design of the orifice. [26]
A nanoparticle sizer, also known as a nanoparticle analyzer, is a device used to measure the size, size distribution, and concentration of nanoparticles in a sample. [27] [28] The size of nanoparticles is typically in the range of 1 to 100 nanometers (nm), and they are much smaller than the particles that can be measured with conventional particle size analyzers. [29]
Miniemulsions have wide application in the synthesis of nanomaterials and in the pharmaceutical and food industries. [30] [31] For example, miniemulsion-based processes are, therefore, particularly adapted for the generation of nanomaterials. There is a fundamental difference between traditional emulsion polymerisation and a miniemulsion polymerisation. Particle formation in the former is a mixture of micellar and homogeneous nucleation, particles formed via miniemulsion however are mainly formed by droplet nucleation. In the pharmaceutical industry, oil droplets act as tiny containers that carry water-insoluble drugs, and the water provides a mild environment that is compatible with the human body. [32] [33] Moreover, nanoemulsions that carry drugs allow the drugs to crystallize in a controlled size with a good dissolution rate. [34] [35] Finally, in the food industry, miniemulsions can not only be loaded with water-insoluble nutrients, such as beta-carotene and curcumin, but also improve the nutrients' digestibility. [12] Miniemulsions are also used in the creation of cannabinoid infused beverages and foods. Emulsifying cannabiniods has shown to increase bioavailability and digestion time. [36]
A miniemulsion (also known as nanoemulsion) is a particular type of emulsion. A miniemulsion is obtained by ultrasonicating a mixture comprising two immiscible liquid phases (for example, oil and water), one or more surfactants and, possibly, one or more co-surfactants (typical examples are hexadecane or cetyl alcohol). They usually have nanodroplets with uniform size distribution (20–500 nm) and are also known as sub-micron, mini-, and ultra-fine grain emulsions. [1]
Mini-emulsion: emulsion in which the particles of the dispersed phase have diameters in the range from approximately 50 nm to 1 μm.
Note 1: Mini-emulsions are usually stabilized against diffusion degradation (Ostwald ripening (ref. [6] )) by a compound insoluble in the continuous phase.
Note 2: The dispersed phase contains mixed stabilizers, e.g., an ionic surfactant, such as sodium dodecyl sulfate (n-dodecyl sulfate sodium) and a short aliphatic chain alcohol ("co-surfactant") for colloidal stability, or a water-insoluble compound, such as a hydrocarbon ("co-stabilizer" frequently and improperly called a "co-surfactant") limiting diffusion degradation. Mini-emulsions are usually stable for at least several days. [7]
Mini-emulsion polymerization: Polymerization of a mini-emulsion of monomer in which all of the polymerization occurs within preexisting monomer particles without the formation of new particles. [8]
There are two general types of methods for preparing miniemulsions:
Miniemulsions are kinetically stable but thermodynamically unstable. [13] Oil and water are incompatible in nature, and the interface between them is not favored. Therefore, given a sufficient amount of time, the oil and water in miniemulsions separate again. Various mechanisms such as gravitational separation, flocculation, coalescence, and Ostwald ripening result in instability. [14] In an ideal miniemulsion system, coalescence and Ostwald ripening are suppressed thanks to the presence of the surfactant and co-surfactant. [9] With the addition of surfactants, stable droplets are then obtained, which have typically a size between 50 and 500 nm. [15] [16]
A sterile filter is a device used to remove microorganisms and other contaminants from a liquid or gas, making it sterile. [17] [18] Sterile filters are commonly used in the medical, pharmaceutical, and biotech industries to ensure that the products produced are free of bacteria and other harmful organisms.
There are different types of filters which include:
A nanogenizer, also known as a high-pressure homogenizer or a microfluidizer, is a device used to create small droplets or particles by applying high pressure to a liquid mixture. [24] These devices can be used to produce nanoemulsions, as well as other types of emulsions and suspensions. [25] They work by passing the mixture through a small orifice under high pressure, which causes the liquid to be sheared and broken into small droplets or particles. The size of the droplets or particles can be controlled by adjusting the pressure and the design of the orifice. [26]
A nanoparticle sizer, also known as a nanoparticle analyzer, is a device used to measure the size, size distribution, and concentration of nanoparticles in a sample. [27] [28] The size of nanoparticles is typically in the range of 1 to 100 nanometers (nm), and they are much smaller than the particles that can be measured with conventional particle size analyzers. [29]
Miniemulsions have wide application in the synthesis of nanomaterials and in the pharmaceutical and food industries. [30] [31] For example, miniemulsion-based processes are, therefore, particularly adapted for the generation of nanomaterials. There is a fundamental difference between traditional emulsion polymerisation and a miniemulsion polymerisation. Particle formation in the former is a mixture of micellar and homogeneous nucleation, particles formed via miniemulsion however are mainly formed by droplet nucleation. In the pharmaceutical industry, oil droplets act as tiny containers that carry water-insoluble drugs, and the water provides a mild environment that is compatible with the human body. [32] [33] Moreover, nanoemulsions that carry drugs allow the drugs to crystallize in a controlled size with a good dissolution rate. [34] [35] Finally, in the food industry, miniemulsions can not only be loaded with water-insoluble nutrients, such as beta-carotene and curcumin, but also improve the nutrients' digestibility. [12] Miniemulsions are also used in the creation of cannabinoid infused beverages and foods. Emulsifying cannabiniods has shown to increase bioavailability and digestion time. [36]