Nanoemulsions are emulsified oil and water systems with droplet sizes between 10-200 nm that are thermodynamically stable and optically clear. They can be produced using high-energy methods like high pressure homogenization or microfluidization or low-energy methods like solvent diffusion or phase inversion. Nanoemulsions have advantages over regular emulsions like improved stability, higher drug loading, and enhanced permeation and absorption of drugs. They have a variety of applications including cosmetics, antimicrobial products, targeted drug delivery, and oral or transdermal delivery of poorly soluble drugs.

1. Nanoemulsions
From Roll No 7-12
MPhil Pharmaceutics
University of Central Punjab

2. Definition
Nanoemulsions are novel drug delivery systems
consisting of emulsified oil and water systems
with average droplet size of 10-200 nm.

3. Introduction
• It is thermodynamically stable, optically clear and
transparent.
• The Nanoemulsion is formed readily and sometimes
spontaneously, generally without high-energy input. In
many cases a co-surfactant or co-solvent is used in
addition to the surfactant
• Now-a-day’s nanoemulsions are frequently used for
various purpose like delivery of vaccine, DNA encoded
drug, antibiotics, cosmetic and topical preparations and
can be administrated via various routes like oral,
pulmonary, ocular and transdermal etc.

4. Difference between Nanoemulsions
and emulsions
Nanoemulsions
• thermodynamically and
kinetically stable.
• clear and translucent
• formed either with or without
high energy input
• 5-10 % surfactant is added in
Nanoemulsion
• Larger surface area to volume
• More Expensive
Emulsions
• Unstable.
• Cloudy
• Emulsion require the large
energy input
• 20-25% surfactant is added in
emulsion preparation.
• smaller surface area to volume
• Less expensive

5. Formulation Additives

6. Types of Nanoemulsions
• oil in water
• water in oil
• Bi-continuous Nanoemulsion
wherein micro domains of oil and water are inter dispersed within
the system.

7. Advantages of Nanoemulsions
• Thermodynamically and kinetically stable therefore flocculation, aggregation,
creaming and coalescence do not occur.
• non toxic and non-irritant.
• Taste masking
• Administered by various routes, such as oral, topical, parentral and transdermal etc.
• Can deliver both hydrophilic and lipophilic drugs.
• Droplet size are nano, so surface area is higher thus increases the rate of absorption
and enhances bioavailability of drug.
• It protects the drug from hydrolysis and oxidation due to encapsulation in oil-droplet.
• Enhances permeation of drug through skin.

8. Characterization Techniques of Nanoemulsion
• Nano-emulsions characteristics will depend on particle size,
viscosity, density, phase inversion, turbidity, refractive index, skin
permeation studies. Techniques used are:
• 1. Thermal Conductivity Technique
• 2. Dynamic Light Scattering Spectrophotometer
• 3. Zeta Potential
• 4. Transmission Electron Microscopy (TEM)
• 5. Drug Content
• 6. Viscosity Measurement
• 7. Phase Analysis Technique

9. Method of Preparation of
Nanoemulsion

10. Methods of Preparation
High-Energy (for lab & industrial preparation)
For o/w &w/o emulsions
1. High pressure homogenization
2. Microfludization
3. Ultrasound emulsification
Low-Energy (for lab preparation)
1. Solvent-diffusion
2. Phase inversion

11. 1. High Pressure Homogenization
• In a high-pressure homogenizer, the dispersion
of two liquids (oily phase and aqueous phase) is
achieved by forcing their mixture through a small
inlet orifice at very high pressure (500 to 5000
psi), which subjects the product to intense
turbulence and hydraulic shear resulting in
extremely fine particles of emulsion .

12. 1.High Pressure Homogenizer
Aqueous phase + oleaginous phase (Heated and pH adjustment)
(Heated and filtration)
Add emulsifying agent
Rapid cooling
High pressure homogenizer (500-20000psi)
Formation of droplet very small size (nano size)

13. 1. Continued

14. 2. Microfluidization
• This device uses a high-pressure positive
displacement pump (500 to 20000psi), which
forces the product through the interaction
chamber, which consists of small channels
called ‘microchannels’.
• The product flows through the microchannels on
to an impingement area resulting in very fine
particles of sub-micron range.

15. 2. Microfluidization

16. 3. Ultrasound emulsification
• In this method, a probe emits ultrasonic waves (20 kHz)
to disintegrate the macroemulsion by means of cavitation
forces. By varying the ultrasonic energy input and time,
the nanoemulsions with desired properties can be
obtained.
• Undesirable for thermolabile drugs and macromolecules
(retinoids, proteins, enzymes and nucleic acids)

17. Low Energy Methods of
Preparation

18. 1. Solvent diffusion method
• oily phase is dissolved in water-miscible organic
solvents, such as acetone, ethanol and ethyl
methyl ketone. The organic phase is poured into
an aqueous phase containing surfactant to yield
spontaneous nanoemulsion by rapid diffusion of
organic solvent. The organic solvent is removed
from the nanoemulsion by a suitable means,
such as vacuum evaporation.

19. 2. Phase Inversion
• In this method the fine dispersions are
produced as the phase inversion occurs
which is caused by varying the
composition and keeping the temperature
constant or vice versa

20. Applications of Nanoemulsion
1. In cosmetics. Due to their lipohilic interior, nanoemulsions are more suitable for the
transport of lipophilic compounds .High skin penetration due to small size
2. Antimicrobial Nanoemulsion.
3. As Non-toxic disinfectant cleaner.
4. In cell culture technology.
5. As a vehicle for Transdermal drug delivery.
6. In cancer therapy and targeted drug delivery.
7. As a mucosal vaccines, nasal route, Alzheimer’s disease, migraine, depression,
schizophrenia, Parkinson’s diseases, meningitis
8. As a vehicle for a occular delivery
9. Use of Nanoemulsions in Cosmetics
10. Improved oral delivery of poorly soluble drugs
11. Percutaneous Route
12. Pulmonary Delivery

21. Commercial Nanoemulsions