Field of invention
The present invention relates to an oil-in-water nanoemulsion based on surfactants (nonionic,
anionic and amphoteric), at least one oil and monohydric alcohol (C2-C4). The present invention
further relates to a process for the preparation of the nanoemulsion.
Background of the invention and prior art
Nano-emulsions have attracted considerable attention in recent years as potential vehicles for the
controlled delivery of cosmetics and personal care products. Nano-emulsions are oil-in-water
(O/W) or water-in-oil (W/O), transparent or translucent, colloidal dispersions, usually in the 20-
200 nm size range that causes their fluorescent blue shining appearance. An advantage in using
nano-emulsions compared to ordinary emulsion, is their ability, as delivery systems, to improve
the bioavailability and bioefficacy of both hydrophilic and lipophilic bioactives in their delivery.
Nano-emulsions render possible different visual aspects, richness and skin feel in a great variety
of products such as lotions, transparent milks and crystal-clear gels with different rheological
behavior, properties which themselves represent biophysical and sensorial benefits highly valued
by consumers.

The formulation of nanoemulsion based cosmetics involves breaking micron sized emulsion to
nanozised smaller particles. Conventionally methods for breaking the larger particles to smaller
particles involve uses of high pressure homogenization, ultra sonication, phase inversion
temperature etc. Therefore the conventional production of nanoemulsion requires either
significant amount energy (high pressure homogenization, ultra sonication, heating/cooling
steps) and/or the use of ethoxylated emulsifiers. The production of naoemulsion according to the
phase inversion temperature (PIT) method requires use of the temperature-dependent phase
behavior of ethoxylated emulsifiers. The use of ethoxylated emulsifiers and the large energy
consumption that is required for the heating/cooling steps is crucial when using the standard PIT
method for the production of nanoemulsions.
The major disadvantages of using conventional procedures are
• Consumption of high energy that impart cost to the production process
• Use of specialized instruments (High pressure homogenizer, ultra sonication etc) that
impart cost to the production process
High temperature that leads to limitation in incorporating temperature sensitive active
ingredients in nanoemulsion
US6461625 relates to a nanoemulsion based on a surfactant chosen from alkoxylated alkenyl
succinates, alkoxylated alkenyl succinates of glucose and alkoxylated alkenyl succinates of
methylglucose and at least one oil having a molecular weight greater than 400, where the ratio by
weight of the amount of oily phase to the amount of surfactant from 2 to 10. According to '625,
the emulsions comprises additives for improving the transparency of the formulation. These
additives are preferably chosen from the group formed by: lower alcohols comprising from 1 to 8
carbon atoms and more particularly from 2 to 6 carbon atoms, such as ethanol; glycols such as
glycerol, propylene glycol, 1,3-butylene glycol, dipropylene glycol, pentylene glycol, isoprene
glycol and polyethylene glycols comprising from 4 to 16 and preferably 8 to 12 ethylene oxide
units; sugars such as glucose, fructose, maltose, lactose and sucrose.

US6419946 relates to nanoemulsion based on a surfactant chosen from mixed esters of a fatty
acid or of a fatty alcohol, of a carboxylic acid and of glycerol and on at least one oil having a
molecular weight of greater than 400, the ratio by weight of the amount of oily phase to the
amount of surfactant ranging from 2 to lO.The process for preparation of nanoemulsion involves
formation of pre-emulsion and homogenization of the mixture at a pressure ranging from 6 X 10
7Pato l8 X 107Pa.
Uses of homogenization process for foaming surfactant system is difficult and also non desirable
because of formation of foam while passing the surfactant system in HPH from very high to zero
pressure.
However, there is a need to provide the nanoemulsion forms spontaneously without use of high
pressure homogenization and instrument alike and without using high temperature.
Objects of the invention
It is an object of the present invention to overcome the drawbacks of the prior arts.
It is another object of the present invention to provide an oil-in-water nanoemulsion based on
surfactants (nonionic, anionic and amphoteric), at least one oil and monohydric alcohol (C2-C4).
It is yet another object of the present invention to provide a process for the preparation of the
nanoemulsion.
Summary of the invention
It is an aspect of the present invention to provide an oil-in-water nanoemulsion comprising
(i) Oil phase in the concentration range of from about 0.01 % w/w to 1% w/w.
(ii) Non-ionic surfactant in the concentration range of from about 0.01 % w/w to 5%
w/w.

(iii) Anionic surfactant in the concentration range of from about 0.2 % w/w to 8%
w/w.
(iv) Amphoteric surfactant in the concentration range of from about 0.05 % w/w to
2% w/w.
(v) Water phase in the concentration range of from about 90 % w/w to 99% w/w.
(vi) Optionally adding co-surfactant in the concentration range of from about 0.02 %
w/w to 1% w/w.
It is another aspect of the present invention to provide a process for the preparation of the
nanoemulsion comprising the steps of:
1. Weighing nonionic surfactant in a container
2. Weighing oil and adding in the nonionic surfactant as mentioned in step 1 whjle stirring
gently
3. Weighing co-surfactant in the mixture as mentioned in step 2 while stirring gently
4. Weighing anionic surfactant in the mixture as mentioned in step 3 while stirring gently
5. Weighing amphoteric surfactant in the mixture obtained in step 4 while stirring gently
until a transparent system was obtained
6. Weighing water and adding the same into the mixture obtained in step 5 and continue
stirring
7. Preparation of nanoemulsion with and/or without diluting transparent solution obtained in
step 5 by appropriate amount of water.
Brief description of the accompanying figures
Figure 1 illustrates particle size distribution of the nanoemulsion
Figure 2 illustrates the antioxidant activity-delivery of antioxidant in skin

Figure 3 illustrates particle size distribution of the milky white solution obtained in Example 3.
From the figure it is evident that system is populated with particles having different sizes.
Figure 4 illustrates particle size distribution of the milky white solution obtained in Example 4.
From the figure it is evident that system is populated with particles having different sizes.
Figure 5 illustrates the particle size distribution of the nanoemulsion system disclosed in the
present invention.
Figure 6 illustrates that delivery of active (ascorbic acid) in the skin is much more efficient from
nanoemulsion (N5) when compared with surfactant mixture (surf) and blank (without active)
(blnk).
Detailed description of the invention
The present invention relates to an O/W nanoemulsion based on surfactants (noionic, anionic and
amphoteric), at least one oil and monohydric alcohol (C2 - C4). The invention also relates to a
process for the preparation of the naoemulsion and its uses in cosmetics and dejmatological
applications/products. The particle size of the nanoemulsion ranges from 20 to 180 nm.
Nanoemulsions are typically not easy to produce as they require either high-pressure
homogenizers or very specific manufacturing processes. Nanoemulsions do not form
spontaneously; an external shear must be applied to rupture larger droplets into smaller ones,
high-pressure microfluidic devices to rupture droplets in concentrated emulsions to smaller one.
The present invention discloses a process of making nanoemulsion without use of any of the
conventional techniques (high pressure homogenization, ultra sonication, high temperature
heating/cooling, PIT etc)
The process of preparation of the nanoemulsion comprise the steps of

1. Weighing nonionic surfactant in a container
2. Weighing oil and adding in the nonionic surfactant as mentioned in step 1 while stirring
gently
3. Weighing co-surfactant in the mixture as mentioned in step 2 while stirring gently
4. Weighing anionic surfactant in the mixture as mentioned in step 3 while stirring gently
5. Weighing amphoteric surfactant in the mixture obtained in step 4 while stirring gently
until a transparent system was obtained
6. Weighing water and adding the same into the mixture obtained in step 5 and continue
stirring
7. preparation of the nanoemulsion with and/or without diluting transparent solution
obtained in step 5 by appropriate amount of water.
Further according to the present invention, the nanoemulsion composition comprises the
following components:
a. Oil phase in the concentration range of from about 0.01 % w/w to 1% w/w.
b. Non-ionic surfactant in the concentration range of from about 0.01 % w/w to 5% w/w.
c. Anionic surfactant in the concentration range of from about 0.2 % w/w to 8% w/w.
d. Amphoteric surfactant in the concentration range of from about 0.05 % w/w to 2% w/w.
e. Water phase in the concentration range of from about 90 % w/w to 99% w/w.
f. Optionally adding co-surfactant in the concentration range of from about 0.02 % w/w to
1% w/w.
Suitable co-surfactant as per the present invention is selected from short chain C2 to C4
monohydric or dihydric alcohol. Most preferred co-surfactant used in the present invention is
ethanol.
According to the present invention the oil phase is selected from but not limited to synthetic,
natural oils, monoglyceride oil, diglyceride oil and essential oil like Isopropyl
myristate,Helianthus Annuus (Sunflower) Seed Oil, Oryza Sativa (Rice) Bran Oil, Sesamum

Indicum (Sesame) Seed Oil, Glycine Soja (Soybean) Oil, Olea Europaea (Olive) Oil, mineral oil,
coconut oil, apricot oil, cucumber seed oil, Macadamia nut oil, castor oil, grape seed oil, walnut
oil, hazelnut oil, pomegranate seed oil, kiwi seed oil, Bisabolol oil, Raspberry Seed Oil,
Cranberry Seed Oil, almond oil, jojoba oil, wheat germ oil and their mixtures thereof. Essential
oils like Basil oil, Cedarwood oil, Chamomile German oil, Chamomile Roman oil, Cinnamon
Leaf oil, Citronella oil, Clary Sage oil , Clove Leaf oil , Eucalyptus oil , Frankincense oil, ,
Geranium oil, Ginger oil, Grape Fruit oil, Jasmine oil, , Lavender oil, Lemon oil, Lemon Grass
oil, Mandarin oil, Orange oil (sweet), Patchouli oil, Peppermint oil, Rose oil, , Rosemary oil,
Sandal oil, Tea Tree oil, Thyme oil,, Vetiver oil, Wintergreen oil, Ylang Ylang oil.
The preferable oil is sunflower oil, almond oil, macadamia nut oil, jojoba oil and their mixture
thereof.
Preferably the anionic surfactant is selected from but are not limited to anionic surfactants
derived from plant-derived glycerides, more preferably from at least two different sources are
used (e.g. palm oil and coconut oil). Such glycerides usually contain about 8 to 24 aliphatic
carbon atoms. Some examples of vegetable oils from which anionic surfactants are derived
include, but are not limited to palm oil, palm kernel oil, olive oil, coconut oil, soybean oil,
almond oil, jojoba oil, and avocado oil. Other anionic surfactants may also be used in place of or
in conjunction with plant-derived or animal-derived anionic surfactants. Some examples of such
anionic surfactants include but are not limited to polymeric surfactants such as PEG 7 glyceryl
cocoate,sodium laureth-6 carboxylate, sodium lauryl sarcosinate, sodium lauramido diacetate,
sodium trideceth-7 carboxylate, sodium stearoyl lactalbumin, and mixtures thereof. Sulfur-
containing anionic surfactants, such as alkoyl isethionates including ammonium cocoyl
isethionate, sodium cocoyl isethionate, sodium lauroyl isethionate, sodium
tridecylbenzenesulfonate and mixtures thereof may also be used. Surfactants derived from amino
acid such as glycinate, sulfosuccinate may also be used. Alternatively, synthetically prepared
fatty acids (e.g. by oxidation of petroleum stocks or by the Fischer-Tropsch process) may be
used alone or in combination with the fatty acid salts of natural origin. Sodium laureth sulfate, or
sodium lauryl ether sulfate SLES nEO, where n may vary from 1 to 7, glutamate such as

disodiumcocoyl glutamate, sulfosuccinate and mixtures thereof are the preferred anionic
surfactants.
Preferably the amphoteric surfactant is selected from and is not limited to derivatives of aliphatic
secondary and tertiary amines in which the aliphatic radical can be straight chain or branched
and wherein one of the aliphatic substituents contains from about 8 to about 18 carbon atoms and
one contains an anionic water solubilizing group, e.g., carboxy, sulfonate, sulfate, phosphate, or
phosphonate. Examples of compounds falling within this definition are sodium 3-
dodecylaminopropionate, sodium 3-dodecylaminopropane sulfonate; N-alkyltaurines, N-higher
alkyl aspartic acids. Other amphoterics such as betaines are also useful in the present
composition. Examples of betaines useful herein include the high alkyl betaines such as coco
dimethyl carboxymethyl betaine, lauryl dimethyl carboxy-methyl betaine, lauryl dimethyl alpha-
carboxyethyl betaine, cetyl dimethyl carboxymethyl betaine, lauryl bis-(2-hydroxyethyl)carboxy
methyl betaine, stearyl bis-(2-hydroxypropyl)carboxymethyl betaine, oleyl dimethyl gamma-
carboxypropyl betaine, lauryl bis-(2-hydro-xypropyl)alpha-carboxyet-hyl betaine, coco dimethyl
carboxymethyl betaine, lauryl dimethyl carboxymethyl betaine, and stearyl bis-(2-
hydroxypropyl) carboxymethyl betaine, and sodium lauryl diethylene diamnioglycinate),
sultaines (e.g. cocamidopropyl hydroxysultaine) and sodium lauryl sarcosinate, and mixtures
thereof.
Lauryl betaine, cocoamidobetaines, oleyl betaine, caprylamidopropyJ betaine,
isostearylamidopropyl betaine, coco imidoazolinium betaine Cocamidopropyl betaine CAPB,
succinate, cocobetaine, lauroamidopropyl betaines and mixtures thereof are the preferred
amphoteric surfactant. Preferably the co-surfactant is selected from monohydric alcohol (C2-C4),
optionally ethoxylated sorbitan esters of (C12 to C18) free fatty acid.
Nonionic surfactant is selected from and is not limited to condensation products of long chain
alcohols with sugar or starch polymers (e.g. decyl polyglucoside and lauryl polyglucoside),
amides (e.g. cocoamide diethanolamine and cocoamide monoethanolamine), alkylene oxide
derived surfactants (e.g. ceteth-6, ceteareth6, steareth-6, PEG-12 stearate, and PEG-200 glyceryl
tallowate), ethoxylated and/or propoxylated (C 5-C 12 alkyl)phenols ethers containing 5 to 20
EO or PO units (such as polyethylene glycol nonylphenyl ethers, polyethylene glycol

octylphenyl ethers, also known under the generic tradename Polystep®), polyethylene glycol
sorbitol ether containing 3 to 30 EO units (such as sorbitol esters with oleic, myristic, stearic,
palmitic acid also known as those known under the tradenames Tweens® from ICI or
Glycosperse® from LONZA), sucrose esters with C8-C20 fatty acid (such as sucrose esters with
oleic, palmitic or stearic acid, such as Ryoto Sugar Ester M-1695 commercialized by Mitsubishi -
Kagaku Foods Corporation), ethoxylated aliphatic C6-C20 alcohols containing 2 to 30 EO units
(such as ethoxylated secondary C 6-C20 alcohols), C8-C20 polyglyceryl esters (such as glycerol-
polyethylene glycol oxystearate commercialized by BASF under the trade name Chromophor®
CO40), polyethylene glycol and polypropylene glycol block copolymers (such as those known
under the tradename Pluronics® from BASF), ethoxylated glycol ether containing 2 to 30 EO
units (such as PEG-10 stearyl ether also known under the trade name Volpo® S-10 from
CRODA), or polyethylene glycol mono-or-diester of aliphatic C5-C11 carboxylic acids
containing 2 to 10 EO units (EO stands for ethylene oxide and PO stands for propylene oxide),
and mixtures thereof. (C8 - C14) Alkyl glucoside such as Decyl Glucoside, polysorbates,
Caprylyl/Capryl Glucoside and mixtures thereof are the preferred non-ionic surfactant. The non-
ionic surfactant is present in a range of about 5.5-8.8 wt%.
Further according to the present invention the nanoemulsion forms simultaneously without use of
high pressure homogenization and instrumental alike and without using high temperature. It is
surprisingly found that mixing the component in appropriate combination leads to the formation
of nanoemulsion without the use of high pressure homogenization, sonication, PIT, high
temperature. Elimination of any one of the components or alteration of the composition leads to
formation of cloudy or phase separated systems with higher size.
According to the present invention the amount of the ingredients are essential for theformation of
nanoemulsion of the present invention. Any alteration from the specific amount will lead to
phase separation.The oil-in-water nanoemulsion has oil drops with small grain sizes and stable
storage and can be applied in cosmetics or cosmeceutical and to care of skin, hair, skin around
eyes and on the face etc. a delivery system for cosmetics active ingredients (including
temperature sensitive)
Figure 6 demonstrates the penetration/delivery of the active ingredient through nanoemulsion
disclosed in the present invention. The active ingredient selected is ascorbic acid; 1% of ascorbic

acid is incorporated in surfactant system and nanoemulsion of the preset invention and both of
them were applied on separate places of skin and strips were taken out for four skin layers from
each part and were analyzed for antioxidant activity. The data obtained clearly depicts that
nanoemulsion provide enhanced delivery of active to the skin.
The present invention is now described by way of non-limiting illustrative Example 1
Process for the preparation of the nanoemulsion.
Weighing 0.75 wt% of nonionic surfactant in a container. Adding to the nonionic surfactant 0.16
wt% oil while stirring gently. To this mixture, 0.24wt% of co-surfactant is added while stirring
gently. 2.43wt% of anionic surfactant is added in the mixture as mentioned above while stirring
gently. Weighing 0.53 wt% of amphoteric surfactant is added to the mixture obtained while
stirring gently until a transparent system was obtained. The nanoemulsion is prepared with
and/or without diluting transparent solution obtained in step 5 by adding 95.9 wt% of water.
Process:
Step 1: Weighing 0.74 gm of Decy glucoside in a container
Step 2: Weighing 0.16gm of Isopropyl myristate and adding in the solution as mentioned in step
1 while stirring gently
Step 3: Weighing 0.24 gm of ethanol in the mixture as mentioned in step 2 while stirring gently
Step 4: Weighing 2.43 gm of Sodium lauroyl sarcosinate in the mixture as mentioned in step 3
while stirring gently
Step 5: Weighing 0.53 gm of Cocaamido propyl betaine in the mixture obtained in step 4 while
stirring gently

Step 6: Weighing 95.5 gm of water in the mixture as obtained in step 5 and continues stirring for
20 - 40 mins to get the nanoemulsion
Observation: A transparent florescent white/blue homogeneous solution was obtained and its
particles size measurement is depicted in Figure 1.

Example 2:
Process:
Step 1: Weighing 1.48 gm of Decy glucoside in a container
Step 2: Weighing 0.32 gm of Isopropyl myristate and adding in the solutiont as mentioned in
step 1 while stirring gently
Step 3: Weighing 0.50 gm of ethanol in the mixture as mentioned in step 2 while stirring gently
Step 4: Weighing 4.86 gm of Sodium lauroyl sarcosinate in the mixture as mentioned in step 3
while stirring gently

Step 5: Weighing 1.05 gm of Cocaamido propyl betaine in the mixture obtained in step 4 while
stirring gently and adding 1.77 gm of water. Step 6: Continue stirring for 20 - 40 mins to get the
nanoemulsion
Step 7: Diluting the solution obtained in step 5 by 90 gm of water.
Observation: A transparent florescent white/blue homogeneous solution was obtained and its
particles size measurement is depicted in Figure 2.

Table 3. Compositions of nanoemulsions

Process:
Step 1: Weighing 1.48 g of decyl glucoside in a container
Step 2. Weighing 0.32 g of isopropyl myristate and adding the same in the container containing
decyl glucoside as mentioned in step 1 and mix well
Step 3. Weighing 0.505 gm ethanol and adding the same into the mixture obtained in step 2 and
mix well
Step 4. Weighing 4.863 gm of Sodium lauroyl sarcosinate and adding the same into the mixture
obtained in step 3 and mix well
Step 5. Weighing 1.057gm Cocaamido propyl betaine and adding the same into the mixture
obtained in step 4 and mix well
Step 6. Weighing 1.75 gm water and adding the same into the mixture obtained in step 5 and
mixing well under gentle stirring
Step 7. Adding 2 gm further water into the mixture obtained in step 6 and mix well
Observation: A milky white heterogeneous solution was obtained and its particle size
measurement is depicted in figure 3.



Process: Step 1: Weighing 5.92 gm of Decy glucoside in a container
Step 2: Weighing 1.28 gm of Isopropyl myristate and adding in the solution as mentioned in step
1 while stirring gently
Step 3: Weighing 1.92 gm of ethanol in the mixture as mentioned in step 2 while stirring gently
Step 4: Weighing 19.452 gm of Sodium lauroyl sarcosinate in the mixture as mentioned in step 3
while stirring gently
Step 5: Weighing 4.228 gm of Cocaamido propyl betaine in the mixture obtained in step 4 while
stirring gently
Step 6. Weighing 67.2 gm water and add the same into the mixture obtained in step 5 and mix
well under constant gentle stirring for 20 -40 mins
Observation : Phase Separated, top layer opaque and bottom layer transparent. A milky white
heterogeneous solution was obtained and its particles size measurement is depicted in figure 4.

WE CLAIM:
1. An oil-in-water nanoemulsion comprising
(i) Oil phase in the concentration range of from about 0.01 % w/w to 1%
w/w.
(ii) Non-ionic surfactant in the concentration range of from about 0.01 % w/w
to 5% w/w.
(iii) Anionic surfactant in the concentration range of from about 0.2 % w/w to
8% w/w.
(iv) Amphoteric surfactant in the concentration range of from about 0.05 %
w/w to 2% w/w.
(v) Water phase in the concentration range of from about 90 % w/w to 99%
w/w.
(vi) Optionally adding co-surfactant in the concentration range of from about
0.02 % w/w to 1% w/w.
2. The oil-in-water nanoemulsion as claimed in claim 1, wherein the oil phase is selected
from sunflower oil, almond oil, micademia nut oil, jojoba oil, Isopropyl palmitate and a
mixture thereof.
3. The oil-in-water nanoemulsion as claimed in claim 1, wherein the non-ionic surfactant is
selected from decyl glucosides, lauryl glucosides, Cetearyl glucoside, Polysorbate 20,
Polysorbate 60 , Polysorbate 80, PEG-40 Castor Oil and a mixture thereof.
4. The oil-in-water nanoemulsion as claimed in claim 1, wherein the anionic surfactant is
selected from Sodium lauryl sulphate, sodium lauryl ether sulfate , sodium laureth
sulfosuccinate, sodium lauryl sarcosinate, PEG 7 glyceryl cocoate.
5. The oil-in-water nanoemulsion as claimed in claim 1, wherein the amphoteric surfactant
is a betaine.

6. The oil-in-water nanoemulsion as claimed in claim 1, wherein the co-surfactant is
selected from alcohols (C2 to C4).
7. A process for the preparation of the oil-in-water nanoemulsions comprising the steps of:
i. Weighing nonionic surfactant in a container
ii. Weighing oil and adding in the nonionic surfactant as mentioned in step 1
while stirring gently
iii. Weighing co-surfactant in the mixture as mentioned in step 2 while
stirring gently
iv. Weighing anionic surfactant in the mixture as mentioned in step 3 while
stirring gently
v. Weighing amphoteric surfactant in the mixture obtained in step 4 while
stirring gently until a transparent system was obtained
vi. Weighing water and adding the same into the mixture obtained in step 5
and continue stirring
vii. Preparation of the nanoemulsion with and/or without diluting transparent
solution obtained in step 5 with appropriate amount of water.

ABSTRACT

The present invention provides an oil-in-water nanoemulsion comprising
(i) Oil phase in the concentration range of from about 0.01 % w/w to 1% w/w.
(ii) Non-ionic surfactant in the concentration range of from about 0.01% w/w to 5%
w/w.
(iii) Anionic surfactant in the concentration range of from about 0.2 % w/w to 8%
w/w.
(iv) Amphoteric surfactant in the concentration range of from about 0.05 % w/w to
2% w/w.
(v) Water phase in the concentration range of from about 90 % w/w to 99% w/w.
(vi) Optionally adding co-surfactant in the concentration range of from about 0.02 %
w/w to 1% w/w.
The present invention further provides a process for the preparation of the nanoemulsion
comprising the steps of:
1. Weighing nonionic surfactant in a container
2. Weighing oil and adding in the nonionic surfactant as mentioned in step 1 while stirring
gently
3. Weighing co-surfactant in the mixture as mentioned in step 2 while stirring gently
4. Weighing anionic surfactant in the mixture as mentioned in step 3 while stirring gently
5. Weighing amphoteric surfactant in the mixture obtained in step 4 while stirring gently
until a transparent system was obtained
6. Weighing water and adding the same into the mixture obtained in step 5 and continue
stirring
7. Preparation of nanoemulsion with and/or without diluting transparent solution obtained in
step 5 by appropriate amount of water.