An overview of nanoemulsion: concepts of development and cosmeceutical applications

Figures & data

Figure 1. Graphic diagram of water-in-oil microemulsions (a) and nanoemulsions (b), consisting of oil, water and surfactant. The structure of the particles in both types of colloidal dispersion is similar, with a hydrophobic shell of oil and surfactant tails and a hydrophilic core of water and surfactant head groups.

Table 1. Patent list on nanotechnology-based cosmeceuticals.

Title	Publication number	Publication date	Applicant
Aqueous photoprotective composition comprising hydrophilic metal oxide nanopigments and a vinylpyrrolidone homopolymer	EP1768749B1	2008-10-15	L'Oreal SA
Cosmetic pigment composition containing gold or silver nano-particles	US 20090022765A1	2009-01-22	Korea Research Institute of Bioscience and Biotechnology
Zeolite based UV absorbing and sunscreen compositions	US20050276761A1	2005-12-15	Gupta Shyam K
Skin whitening methods and compositions based on zeolite–active oxygen donor complexes	US20070166339A1	2007-07-19	BIODERM Research
Cosmetic composition containing retinol stabilized by porous polymer beads and nanoemulsion	US 20130095157A1	2013-04-18	Act Co Ltd
Nano-emulsion and cosmetic product compounded therewith	JP 2008127327A	2008-06-05	Ands Corporation
Healthy collagen cosmetic	JP 2005206567A	2005-08-04	Iwamoto Shigemi
Nanoemulsion comprising metabolites of ginseng saponin and a skin-care composition for anti-aging containing the same	EP 1327434A1	2003-07-16	Pacific Corp

Table 2. Examples of cosmeceutical products that used nanotechnology.

Brand/product type	Application	Active compounds	Delivery system	Product name
Cosmetic Dermatology, Inc.	Anti-aging	Peptide and minerals	Nanoencapsulated ingredients	Dr. Brandt Laser Relief
Cosmetic Dermatology, Inc.	Anti-aging	Peptide	Nanoparticles	Dr. Brandt Laser Tight
L’Oréal	Sunscreen	Metal oxide (titanium dioxide and zinc oxide)	Nanopigments	UV Perfect Series SPF 50
L’Oréal	Anti-aging	Vitamin A	Nanosomes	Revitalift
Lancôme Paris	Sunscreen	Vitamin	Nanocapsules	Lancome Soleil Instant Cooling Sun Spritz
Lancôme Paris	Anti-Aging	Vitamin	Nanocapsules	Lancome Soleil Soft-Touch Anti-Wrinkle Sun Cream SPF 15
DS Laboratories	Anti-acne	Wheat-Germ, Barley-Germ, Arnica	Nanosomes	DS Laboratories Trioxil Anti-Acne Gel
Wilma Schumann	Anti-acne	Vitamin E	Nanoparticle	Wilma Schumann Acne Kit

Table 3. HLB value for various applications.

HLB value	Applications
0 to 3	Mixing unlike oils together
From 4 to 6	Making water-in-oil emulsions
From 7 to 9	Wetting powders into oils
From 8 to 16	Making oil-in-water emulsions
From 13 to 15	Making detergent solutions
From 13 to 18	Solubilising oils (micro-emulsifying) into water

Figure 2. Schematic diagram of water-in-oil (W/O) and oil-in-water (O/W) nanoemulsion consisting of surfactant micelles.

Figure 3. Schematic drawing of catastrophic and transitional phase inversion for the preparation of oil in water emulsions [113].

Table 4. Comparison between high and low energy methods to formulate nanoemulsions.

Emulsification process	Mechanism of emulsification	Advantages	Disadvantages	References
Low energy
Phase inversion composition	Progressive dilution of the dispersed phase to change the interfacial film curvature.	Allows scale-up production, low cost and no heating required in production process.	Requires the presence of liquid crystal (LC) or mid-range microemulsion (ME) phases. Requires gradual addition of one phase into another.	[103, 107]
Phase inversion temperature	Temperature variation to change the interfacial film curvature.	Allows scale-up production and low cost.	Requires the presence of LC or ME phases; Heat energy is required. Limited to the non-ionic surfactant.	[112, 114, 115]
High energy
High-shear stirring using a rotor/ stator system	Generate very high shear stresses due to focused delivery of energy. Highly localized energy dissipation rates near the mixing head.	Allows scale-up production. Allowing continuous production of emulsions with a stirring speed of up to 36,000 rpm.	Higher power consumptions than conventional mechanically stirred vessels.	[124, 125, 127]
High-pressure homogenization	Shear, collision and cavitation	More flexibility for selecting surfactant and internal structure of emulsion than low energy processes, and shorter process time.	Not suitable for thermo- or shear-sensitive compounds and more expensive than other equipment.	[118, 130, 131]
Ultrasonication generator/sonication	Cavitation	More flexibility for selecting surfactant and internal structure of emulsion than low energy processes, as well as less costly equipment.	Can only process small batches of emulsions at a time.	[120, 136, 140]
Microfluidization	High-pressure injection		Not suitable for large-scale manufacturing and more expensive than other equipment	[147, 149]

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