2. Nanoemulsions
• Dispersion of two immiscible liquids stabilized
by a surfactant
• Thermodynamically and kinetically stable
• Droplets from 5 to 200 nm
3. Nanoemulsions
Emulsion
Microemulsion
Nanoemulsion
Thermodynamically unstable
Opaque
High energy required to form
Thermodynamically stable
Clear
It forms spontaneously
Thermodynamically or kinetically stable
Clear
High shear application to form
Int. J. Nanomed. 2014,9,pp 1-8
4. Nanoemulsions - Classification
Depending on the composition :
O/W : oil droplets dispersed in continuous aqueous phase
W/O : water droplets are dispersed in continuous oil phase
Bi-continuous : microdomains of oil and water are dispersed within the system
J. Mat. Chem. 2012, 22, pp 9767-9773
5. Nanoemulsions - Preparation
Materials
Methods
Low energy methods High energy methods
Phase Inversion Temperature
Phase Inversion Composition
Solvent Displacement
Use of devices with high
mechanical energy to create
nanoemulsions
Oils Surfactants Aqueous phase
Capryol90
Lauroglycol90
Labrafil CS
Poloxamer124
PEG4000
Captex 355
Captex 8000
Witepsol
Myritol 318
8. Nanoemulsions - Drug Delivery
Advantages
Increase drug loading
Enhance drug solubility
Bioavailability
Controlled drug delivery
Protection of drug
Disadvantages
Expensive process
Stability
Solubility
Lack of understanding of interfacial chemistry
More proofs about more benefits compared to classical macroemulsions
J. Phys. Chem. C 2008, 112 (33), 12669-12676.
10. Conclusions
Nanoemulsions are receiving increasing attention as drug carrier
Applicable for almost all routes of delivery
Wide range of molecules can be loaded
New technology could be developed to overcome the
poor absorption and miscibility of some phytopharmaceutical