High Internal Phase Emulsions

This invention relates to a composition suitable for forming a high internal phase emulsion, high internal phase emulsions formed therefrom and methods of forming high internal emulsions. The invention particularly relates to compositions formed from natural ingredients and in particular to compositions formed from vegetable oil components.

There are many different products which are designed to be applied to the skin, including creams, liquids and gels. For many cream or gel products, an important factor is the rheological profile of the product. It is common to use products which have a non-Newtonian rheological profile (products which are thixotropic or pseudoplastic). Such products do not run when in packaging and so are easy to handle, but spread easily on the skin's surface when spreading force is applied.

These desirable rheological characteristics can be achieved in a number of different ways. It is important that the rheology remains stable throughout the lifetime of the product. One standard method in the field is to use an oil-in-water emulsion. Such emulsions are commonly stabilised using an emulsifier and a water structuring agent such as carbomer or a natural gum.

Another common type of emulsion that can be used is a water-in-oil emulsion, which is again stabilised using an emulsifier. One such emulsifier for use in water-in-oil emulsions is commercially available as Neocare P3R from Gova Research. This emulsifier is formed from a mixture of polyglyceryl-3 polyricinoleate and polyglyceryl-3 ricinoleate and has a hypophile-lipophile balance (HLB) of 3.5.

An alternative emulsion which has excellent rheological properties is a high internal phase emulsion. A traditional emulsion is formed of a large external phase and a smaller internal phase in which droplets of the internal phase are surrounded by a surfactant and suspended in the external phase. In a high internal phase emulsion (HIPE), the external phase forms a small part of the emulsion. This emulsion is formed by allowing distortion of the droplets in the internal phase from a spherical shape to a polyhedral shape. This distortion is only obtainable by careful selection of specific emulsifier systems. The polyhedral shape of the droplets allows the internal phase to be present in an amount of up to 99% of the total volume of the emulsion. By comparison, for standard packing of spherical particles, the internal phase can be a maximum of approximately 74% of total volume of the emulsion. Therefore, a HIPE according to the present application is an emulsion in which the volume of l the internal phase is at least 75% of the total volume of the emulsion. It is preferred that the internal phase forms at least 80% of the total volume of the emulsion, and more preferably at least 85% of the total volume of the emulsion. Preferably the internal phase forms less than or equal to 95% of the total volume of the emulsion. Where the internal phase is greater than 95%, in some cases the emulsion can become too thick to handle easily and lies outside the preferred viscosity of a cosmetic preparation, which is generally between 500 and 100,000 cps. HIPEs are particularly suitable for use for products to be applied to the skin as they have a suitable rheometry but do not require the use of additional water thickeners as is the case in oil-in-water emulsions. Water-in-oil emulsions also usually have a low viscosity. In order to thicken water-in-oil emulsions, an oil thickener is typically required in large quantities. Suitable thickeners include wax, Bentone Gel® and fumed silica. Disadvantages of using these thickeners in sufficient quantities to include making the resultant product too heavy and also too greasy.

In addition, as water-in-oil HIPEs contain low levels of oil, they are significantly less expensive to produce than conventional water-in-oil emulsions as the oils are more expensive than water.

However, HIPEs commonly do not have high levels of stability. In addition, commercially available HIPEs are commonly formed using silicone oils. Such emulsions are disclosed for example in KR20140070719 and US2003/0064046. Silicone-based oils are not suitable for manufacturers who are attempting to make "natural product" or "organic product"

formulations i.e. formulations whose oils are based on natural products or organic products. Therefore, whilst silicone oils produce HIPEs with excellent properties, the resulting HIPEs are not suitable for many applications. For the purposes of this application, products which are defined as being an "organic product" or a "natural product" are those which comply with the COSMOS-standard as set out at www.cosmos-standard.org.

In addition, when producing HIPEs, there is a requirement to mix the oil and water in order to produce the emulsion. Typically, the mixing needs to be undertaken under high shear in order to obtain the phase shift.

Accordingly, it would be desirable to provide an emulsfiying composition for producing a water-in-oil high internal phase emulsion with high levels of stability. It would be particularly desirable if this composition was formed only using oils formed from natural products. It would be further desirable if it was possible to produce the emulsion without the need for high shear mixing. It would be additionally advantageous to produce the emulsion without the need for heating the reactants so that active ingredients can be included in either the oily phase or the aqueous phase before mixing.

In addition, it would be desirable to provide an oil-based organic composition which was suitable for forming high internal phase emulsions having the above desired properties. It would be further desirable if those high internal phase emulsions could be defined as being natural or organic according to the COSMOS definitions.

Accordingly, in a first aspect of the present invention, there is provided an emulsifying composition for forming a water-in-oil high internal phase emulsion comprising:

at least one polyglycerol ester, wherein the polyglycerol ester has an HLB of from 2 to 7; at least one sorbitan ester; and

at least one emollient ester.

In one embodiment, the emulsifying composition consists of said at least one polyglycerol ester, said at least one sorbitan ester and said at least one emollient ester.

Preferably, the polyglycerol ester has an HLB of from 2 to 5.5. It is preferred that the esters of the emulsifying composition are formed only from natural products or organic products as defined above. Preferably the esters can be considered as natural products as defined above. It is further preferred that all of the components of the composition are formed only from natural products or organic products.

It is preferred that the emulsifying composition contains less than 2 weight percent of silicone oils, preferably less than 1 weight percent, and most preferably does not contain any silicone oils.

Further, it is preferred that the composition is formed only of a mixture of natural esters.

In a second aspect of the present invention, there is provided a composition for producing a water-in-oil high internal phase emulsion comprising the emulsifying composition of the first embodiment and a wax having a melting point of at least 50°C. Preferably, the organic composition additionally comprises an emollient which is not an emollient ester.

In a third aspect of the present invention, there is provided a water-in-oil high internal phase emulsion comprising the emulsifying composition of the first aspect or the composition of the second aspect; a soluble metal salt and water. In a fourth aspect of the present invention, there is provided a method of making a water-in- oil high internal phase emulsion comprising mixing the emulsifying composition of the first aspect with water and a soluble metal salt, wherein the mixing is undertaken at a temperature of from 15 to 25°C. Preferably, the method comprises stirring the oily phase at low shear at room temperature and adding the aqueous phase in small increments. The skilled person understands what is meant by low shear mixing. It is preferred that the shear rate of the stirrer is approximately 500 to 2000 rpm and more preferably approximately 1000 rpm when using a mixer such as an IKA Eurostar 20 with a standard blade. Other similar mixers can be used to achieve the required low shear mixing. Once an initial emulsion has formed between the oil and the water, it is possible to add the aqueous phase more quickly.

The emulsifying composition of the present invention is one which can be mixed with water to produce a stable water-in-oil high internal phase emulsion. Therefore, the emulsifying composition is one which does not contain water. The composition can be mixed with other organic components prior to mixing with water in order to improve the stability of the resulting emulsion, to improve the feel of the resulting emulsion or for other reasons set out below.

The emulsifying composition forms a minor part of the resulting water-in-oil emulsion as the aqueous phase is the major part. It is preferred that the emulsifying composition comprises from 2 to 20 weight percent of the total HIPE, preferably from 3 to 12 weight percent and more preferably from 5 to 9 weight percent.

The emulsifying composition comprises at least one polyglycerol ester, at least one sorbitan ester and at least one emollient ester. A polyglycerol ester is the product of a polyglycerol and one or more carboxylic acids. In the present invention, the polyglycerol preferably has an average of from 2 to 20 glycerine units, more preferably from 3 to 10 glycerine units and even more preferably from 3 to 6 glycerine units. It is particularly preferred that the ester has three glycerine units. The carboxylic acids are preferably naturally occurring carboxylic acids and it is preferred that the carboxylic acids are naturally occurring fatty acids. Preferably the carboxylic acids have from 8 to 22 carbon atoms, which is the length of carbon chains found in naturally occurring fatty acids in triglycerides. The fatty acids can be either linear or branched.

Both saturated and unsaturated fatty acids are suitable. However, unsaturated fatty acids are preferred. One important feature of the polyglycerol esters is the HLB. It is a requirement that the HLB of the polyglycerol ester is from 2 to 7. It is a preferred that the HLB in the present invention is from 2 to 5.5. Preferably, the HLB is from 2 to 4. It is further preferred that the HLB is from 2.5 to 3.5, and particularly preferred from 3 to 3.5. HLB values can either be calculated or determined experimentally. However, the standard methods of calculation, such as those of Griffin (Journal of the Society of Cosmetic Chemists 5 (1654): 259) or Davies (Gas/Liquid and Liquid/Liquid interface: Proceedings of the International Congress of the Surface Activity (1657): 426-438), are not sufficiently accurate for many types of materials. Therefore, the HLB values referred to in the present application are obtained experimentally. It is usual for suppliers of materials to provide HLB values for their products which are obtained

experimentally. The skilled person is aware of suitable methods to determine the HLB value, such as using comparative testing by forming a series of emulsions with an emulsifier and an oil of known HLB value. Suitable polyglycerol esters include polyglyceryl-3-dioleate, which has an average of 3 glycerine units and an average of 2 oleic acid residues per glycerine unit. Other suitable polyglycerol esters include polyglyceryl-6-isostearate and polyglyceryl-6-dioleate.

The polyglycerol ester is present in an amount of 5 to 75 weight percent of the emulsifying composition, preferably from 10 to 45 weight percent and more preferably from 12 to 25 weight percent.

The polyglycerol ester preferably forms from 0.5 to 3 weight percent of the total HIPE, more preferably from 1 to 1 .5 weight percent.

The composition additionally comprises at least one sorbitan ester. A sorbitan ester is the reaction product of sorbitan and one or more carboxylic acids. Preferably the carboxylic acids have from 8 to 22 carbon atoms, which is the length of carbon chains found in naturally occurring fatty acids in triglycerides. Particularly preferred are carboxylic acids having from 16 to 22 carbon atoms and even more preferably having 18 carbon atoms. The fatty acids can be both linear and branched.

Both saturated and unsaturated fatty acids are suitable. However, unsaturated fatty acids are preferred.

Some commercially available sorbitan esters which are suitable for use in the present invention include: Trade Name INCI HLB

Glycomul™ TS KFG/Lonza Sorbitan tristearate 2.1

Lonzest™ SMO /Lonza Sorbitan oleate 4.3

Span 120/Croda Sorbitan isostearate 4.7

Lonzest™ STO /Lonza Sorbitan trioleate 1 .8

Span 83 /Croda Sorbitan sesquioleate 3.7

Suitable sorbitan esters have an HLB of less than 6.0. Preferred sorbitan esters are those having an HLB of less than 4.5. Particularly preferred is sorbitan sesquioleate. HLB values for the sorbitan esters are determined experimentally in the same manner as described above for polyglycerol esters.

The sorbitan esters cannot produce a HIPE as the sole component of the oily phase as they are incapable of distorting the internal phase droplets sufficiently. However, they are effective at stabilizing the water-in-oil HIPE. They are particularly effective at stabilizing the HIPE at lower temperatures (up to and including 40°C). The at least one sorbitan ester is to be used in a total amount of from 1 to 50 weight percent of the emulsifying composition. It is preferred that the total amount of sorbitan ester is from 1 to 10 weight percent of the emulsifying composition, as at higher levels it can give the HIPE a heavy feeling and can make the HIPE less easy to rub in to skin. The sorbitan ester is more preferably present in an amount of from 2 to 6 weight percent and most preferably approximately 3 to 6 weight percent.

It is preferred that the sorbitan ester is present in the final HIPE in an amount greater than 0.1 weight percent, preferably greater than 0.15 weight percent. It is preferably present in an amount of less than or equal to 1 weight percent and preferably less than or equal to 0.5 weight percent. The composition additionally comprises at least one emollient ester. The emollient esters advantageously act as a solvent for the other emulsifying components in the composition. In addition, they form a major part of the external oily phase. They additionally prevent the resulting HIPE from having too high a viscosity and help the texture of the final product. The emollient ester can be liquid or solid. An emollient ester therefore is one which forms part of the oily phase of the resulting HIPE and does not have any surface activity. The emollient ester is preferably the reaction product of an alcohol and a carboxylic acid in which there are no other polar groups such as ether groups in either the alcohol or the carboxylic acid. It is preferred that the emollient ester is an ester based on a carboxylic acid of natural origins. Preferably, the ester is a reaction product of a carboxylic acid having from 8 to 22 carbon atoms or carbonic acid with an alcohol having from 3 to 22 carbon atoms.

Preferably, the carboxylic acid has from 12 to 18 carbon atoms. Preferably the alcohol has a chain length of from 3 to 12 carbon atoms and more preferably from 3 to 6 carbon atoms.

It is preferred that the total number of carbon atoms in the emollient ester is from 12 to 24.

Preferred carboxylic acids include carbonic acid, myristic acid, palmitic acid, stearic acid, caprylic acid and capric acid. Preferred alcohols include isopropanol, ethylhexanol, octyldodecanol and coconut alcohol (a mixture of alcohols including caprylyl alcohol, capryl alcohol, lauryl alcohol and stearyl alcohol produced from coconut oil which is commercially available).

Particularly preferred esters include isopropyl myristate; isopropyl palmitate; dicaprylyl carbonate; octyldodecyl myristate; and coco-caprylate/caprate.

The emollient esters form a major part of the present composition. They are preferably present in the composition in a total amount of from 9 to 95 weight percent of the

composition. It is preferred that the total amount of emollient esters is from 46 to 95 weight percent and more preferably from 65 to 90 weight percent.

It is preferred that the composition comprises at least two emollient esters. It is particularly preferred that the composition comprises two emollient esters. One particularly preferred emulsifying composition comprises:

Material weight %

Isopropyl Palmitate 50-60

Isopropyl Myristate 20-30

Polyglyceryl-3 Dioleate 10-20

Coco-Caprylate/Caprate 2-8

Sorbitan Sesquioleate 2-6

A second particularly preferred emulsifying composition comprises:

Material weight %

Isopropyl Palmitate 65-75

Polyglyceryl-3 Dioleate 15-25

Coco-Caprylate/Caprate 2-8 Sorbitan Sesquioleate 2-6

The emulsifying composition can be mixed with other components to form a high internal phase emulsion. The emulsion is typically produced by mixing an organic/oily phase with an aqueous phase.

The organic phase or oily phase comprises the emulsifying composition. In addition, it optionally comprises at least one other organic component. Preferred additional compounds are emollients other than the emollient esters which form part of the emulsifying composition.

The emollients are typically oils which help lower the viscosity of the HIPE, primarily by increasing the amount of oil in the external phase. The type and amount of oil used also have an impact on the texture of the HIPE.

Optional emollients include vegetable oils, squalane and silicone oils.

Where used, the emollients are selected to maintain the stability of the HIPE.

The emollients are preferably present in an amount of up to 30 weight percent of the oily phase. The additional emollients are present in an amount of from 0 to 5 weight percent of the total HIPE and more preferably from 0 to 2.5 weight percent, such as about 2 weight percent. It is further preferred that the emulsifying composition does not contain any additional emollients, with the only emollients being the emollient esters of the emulsifying composition. Where silicone oils are used, it is preferable that they comprise less than 1 weight percent of the oily phase. It is preferred that silicone oils are not used.

In one preferred embodiment of the present invention, the oily phase additionally comprises at least one wax or butter.

Waxes and butters can improve the skin feel of the final HIPE, even at low levels (less than 0.5 weight % of the final HIPE). The waxes and butters can also improve high temperature stability of the HIPE. The total amount of wax or butter can be up to 2.5 weight percent of the final HIPE. However, it is preferred that the wax is used in a lower amount. It is preferred that a wax or butter is present in the final HIPE in an amount of from 0.25 to 1 weight percent and preferably from 0.5 to 0.75 weight percent of the final HIPE. It is preferred that the butters or waxes have a melting point of at least 50°C and preferably a melting point of at least 60°C. Suitable butters and waxes include sunflower wax, white beeswax, Kesterwax K82D, Dermofeel Viscolid, Cutina CP, BW Ester BW67, Acticire, rice bran wax, Cera Bellina, and Thixcin R.

Despite only being used in small quantities, it appears that the wax or butter is particularly advantageous at improving the stability of the HIPE at temperatures of 50°C. Whilst the HIPEs are rarely exposed to such temperatures in practice, it is considered that the testing of stability at 50°C shows some correlation with stability at lower temperatures. Therefore, it is advantageous, but not essential, for a HIPE to demonstrate stability at 50°C.

Other components which can be included in the oily phase include oil soluble components such as pharmaceutical actives, pigments, fragrances and dyes.

The aqueous phase can additionally contain a preservative. Suitable preservatives are known to the skilled person. Depending on the nature of the preservative, it may more soluble in the oily phase or the aqueous phase. For cosmetic formulations, Euxyl PE 9010 (a liquid preservative based on phenoxyethanol and ethylhexyglycerin) by Schuike and Mayr GmbH is particularly suitable. This preservative is more soluble in the oily phase and so is added to the oily phase.

The aqueous phase primarily comprises water. The aqueous phase is present in an amount of at least 75% of the total volume of the resulting HIPE.

In combination with the emulsifying composition, water is the only essential component to produce a water-in-oil high internal phase emulsion. However, the stability of the emulsion is improved by the addition of other components.

In particular, in order to provide a HIPE with suitable stability, it is necessary to include one or more soluble metal salt. Preferred compounds are group 1 and group 2 metal salts, with group 2 metal salts being further preferred. Preferred counter ions include sulphates, carbonates and nitrates.

Magnesium sulphate is a particularly preferred metal salt.

Where present, the metal salt is used in an amount of from 0.2 to 2 weight percent of the total HIPE. Preferably, the metal salt is used in an amount of from 0.5 to 1.5 weight percent.

The metal salts act to help to partition the emulsifier into the interface, reducing the interfacial tension. This helps to improve the stability of the HIPE. In addition to water, the aqueous phase can additionally include glycerine. The glycerine is present in an amount of from 0 to 10 weight percent of the total HIPE, preferably from 3 to 7 weight percent and more preferably approximately 5 weight percent. The glycerine provides a number of advantages in the final HIPE including improving the texture of the HIPE and also improving freeze thaw stability.

The emulsion is preferably for use on the skin. It is preferred that the emulsion has a pH of from 4 to 9, more preferably from 4 to 8 and more preferably from 5 to 7. The skin typically has a pH of approximately 5.5, and it is particularly preferred that the pH of the emulsion is approximately 5.5. The aqueous phase can additionally contain a preservative. Suitable preservatives are known to the skilled person as discussed above. Where the preservative is more strongly hydrophilic, it is added to the aqueous phase rather than the oily phase.

In a preferred embodiment, particles can be used to stabilise the emulsions. In particular, the particles can help increase the stability of the emulsions during low and high temperature cycling. Suitable particles include clay, insoluble inorganic powders and starches. Suitable inorganic powders are those which have been approved for use in the cosmetics industry. Such powders are often used as pigments. Suitable powders include zinc oxide, aluminium oxide, iron oxide, ammonium manganese pyrophosphate, ferric ferrocyanide, and chromium dioxides. Suitable clays include Kaolin, Bentonite, Talc, Magnesium Aluminium Silicate and Hectorite.

Starches are known for use as stabilizers. The skilled person would be aware of suitable starches which can be used. These include tapioca starch.

Other particles which can be used include organic powders such as charcoal or plant powders. Particularly preferred particles include one or more of zinc oxide powder and tapioca starch. It is preferred that more than one type of particle is present in the emulsion. The particles preferably have a particle size of 0.1 to 200 μηη, more preferably 1 to 100 μηη. It is preferred not to use particles in the nanoscale, that is having a size less than 0.1 μηη (100 nm).

The particles can be added to either the oily phase or the aqueous phase prior to forming the emulsion or can be added to the emulsion after it has been formed. However, it is preferred that the particles are added at the end of the process after the emulsion has been formed. This is particularly true where the particles are heat sensitive. The particles are preferably added in an amount of 1 to 8 weight percent, based on the total weight of the HIPE, and more preferably in an amount of from 1 to 5 weight percent.

The emulsion can be formed from the mixture of the oily phase and the aqueous phase. A third mixture can also be used. This mixture is used to introduce pigments, preservatives and fragrances into the HIPE, where these are not introduced in either the oily phase or aqueous phase. This mixture is typically added after the HIPE has been formed from the first two phases. In particular, where the oily phase contains a wax or butter, it is typically required to heat the mixture in order to form the HIPE. Where heating is required when forming the HIPE, it is preferred to use the third mixture to introduce the pigments, preservatives and fragrances to avoid them breaking down due to the heat.

The HIPE can also be used in pharmaceutical formulations. The active pharmaceutical ingredient can be introduced in any one of the three phases. However, it is preferably introduced in the third mixture.

It is preferred that the components of the third mixture are not heated, because this can cause the active ingredients, such as pharmaceutical, fragrance or pigment, to break down.

Where the method of formation does not involve heating, which is possible in the present application, it is possible to add the third mixture to either the aqueous phase or the oily phase prior to forming the HIPE.

Producing high internal phase emulsions typically has required high shear mixing in order to cause the phase inversion. However, the emulsifying composition of the present invention allows the formation of a HIPE without the need for high speed mixing or for heating of the components.

There are many advantages to being able to form a HIPE without using extreme mixing conditions. First, the method is more energy efficient and therefore less expensive to undertake. In addition, the preparation can be undertaken without the need for specialist high shear mixers and other safety equipment which results from the increased amount of aerosols which result from high shear mixing.

In addition, by using lower shear mixing, there is a reduced amount of risk of damaging the active ingredients either by excessive mixing or heating as part of the process. Low and medium shear mixers are typically cheaper and more easily obtained. For example, it is possible to use general food mixers. This makes it easier for the HIPEs to be produced on a smaller commercial scale from the emulsifying composition of the present invention.

Figures

The invention will be further described with reference to the drawings in which: Figure 1 shows an image of a high internal phase emulsion according to the present invention measured using cryogenic transmission electron microscopy (cryo-TEM).

Examples

The following materials set out in Table 1 were used in producing the HI PEs of the Examples. Table 1

Ethylhexyl Stearate BASF / Cetiol 868

Octyldodecyl Myristate Gattefosse / MOD

Coco-Caprylate/Caprate IQL / Waglinol 20080

Cetearyl Isononanonate BASF/ Cetiol SN

Coco Caprylate BASF / Cetiol C5

Ethylhexyl Palmitate BASF / Cegesoft C24

Emollient

Lecithin IFF Lucas Meyer / Emulmetik

300 IP

Squalane Amyris / Neossance Squalane

Mineral Oil Sonneborn / Benol

Dimethicone 350cs Dow Corning / Dow Corning

200 Fluid 350cs

Wax/butter INCI name

Sunflower wax Helianthus Annus Koster Keunen

(Sunflower) Seed Wax

White Beeswax Cera Alba Koster Keunen

Kesterwax K82D Di-C20-40 Alkyl Dimer Koster Keunen

Dilinoleate

Dermofeel Viscolid Hydrogenated Vegetable Dr Straetmans

Oil

Cutina CP Cetyl Palmitate BASF

BW Ester BW67 Stearyl Beeswax (and) Koster Keunen

Behenyl Beeswax

Acticire Jojoba Esters (and) Gattefosse

Helianthus Annuus

(Sunflower) Seed Wax

(and) Acacia Decurrens

Flower Wax (and)

Polyglycerin-3

Rice Bran Wax Oryza Sativa (Rice) Bran Koster Keunen

Wax

Cera Bellina Polyglyceryl-3 Beeswax Koster Keunen

Thixcin R Trihydroxystearin Elementis

Aqueous Phase

Magnesium Sulphate Reagent grade Glycerine Reagent grade

Water Purified water

Other ingredients

Phenoxyethanol/Ethylhexylglycerin Schulke and Mayr / Euxyl PE based preservative 9010

Examples 1 to 4 and Comparative Examples 1 to 5

An emulsifying composition was made by mixing 1 .5 parts by weight of an ester in accordance with Table 2 below and 5 parts by weight of isopropyl palmitate. An aqueous composition was formed of 5 parts by weight of glycerine, 1 part by weight of magnesium sulphate and 87.5 parts by weight of water to make a total of 100 parts by weight.

An IKA Eurostar 20 overhead stirrer with an impeller head mixed the emulsifying

composition at 1000 rpm. The aqueous composition was added slowly using a Pasteur pipette until one quarter of the mixture had been added. Subsequently, the aqueous composition was added in small portions of approximately 5% of the aqueous composition allowing the mixture to fully emulsify between additions.

Table 2 additionally shows the results of each mixture. It can be seen that only certain polyglycerol esters are capable of forming a HIPE. In addition, although some of the polyglycerol esters were capable of forming a HIPE, the quality and stability of the HIPE was variable.

Table 2

Example 5

Emulsifying compositions were produced using different amounts of sorbitan sesquioleate. The emulsifying composition was produced by mixing amounts of sorbitan sesquioleate as set out in Table 3, 1.25 parts by weight of polyglyceryl-3-dioleate and 4.5 parts by weight of isopropyl palmitate.

The aqueous composition was formed from 5 parts by weight glycerine, 1 part MgSC>4 and a balance of water to form 100 parts by weight of resultant HIPE. The emulsions were formed in the same manner as for Example 1 above.

The stability of the resultant HIPEs was measured by a visual inspection process and is shown in Table 3. The stability is recorded according to the following scale:

1 = perfect stability, no sign of leakage of water or separation at all

2 = some very tiny signs of instability which may include an irregular surface, a few drops of water seen

3= product starting to break down, viscosity drop, water layer seen

4 = 2 separate layers seen, visible separation

5 = no cream visible, product lost viscosity, like water A score of 1 is recorded as good, 2-3 as medium and 4-5 as poor. Table 3

As can be seen, whilst it is possible to form a stable emulsion without the sorbitan ester or a low amount of this ester, the resulting HIPE is not stable at room temperature up to three weeks or at 50°C after only a week.

Therefore, it is preferred that the sorbitan ester is present in the HIPE composition in an amount greater than 0.1 weight percent and preferably greater than 0.15 weight percent. From 0.25 to 0.75 weight percent is particularly preferred. Example 6

Emulsifying compositions were produced using different emollient esters as set out in Table 4. Esters were selected on the basis of their availability, good spreading characteristics, and cost effectiveness.

The following composition formula was used: Emollient ester as listed in Table 4

Polyglyceryl-3 Dioleate 1 .25 parts

Sorbitan Sesquioleate 0.25 parts

Glycerine 5 parts

MgS0 ₄ 1 parts

Water to 100 parts The emulsions were formed in the same manner as for Example 1 above.

Table 4

The results show that the choice of emollient ester affects the thickness of the resulting HIPE and in some cases means that it is not possible to add as much water as is desirable.

Example 7

Different emulsifying compositions were produced using different blends of components to test the stability of the resulting HIPEs at room temperature and 40°C for up to two weeks.

The compositions were mixed according to Table 5, with the components being given in parts by weight:

Table 5

The oily phase was formed by mixing each of the above emulsifying compositions with Euxyl PE9010 preservative.

The aqueous phase was formed of 5 parts glycerine, 1 part MgSC>4 and a balance of water to form a HI PE of 100 parts by weight. The emulsions were formed in the same manner as for Example 1 above. The HIPEs were formed at room temperature.

The HIPEs were tested for initial cosmetic acceptability based on a measure of the ease in which the formulation can be rubbed into the skin on a scale of 1 to 5, with 1 being poor and 5 being excellent. The HIPEs were also tested for stability both fresh and after ageing at either room temperature or 40°C. The stability of the HIPEs was defined as being either good, medium or poor as described above.

The results are set out below in Table 6.

Table 6

Example 8

HIPE compositions were produced using different additional waxes or butters in the oily phase.

The oily phase was produced by mixing the wax or butter in the amount set out in Table 8 with 2 parts by weight of isopropyl myristate, 0.5 parts by weight of preservative and 6 parts by weight of an emulsifying composition having the following components:

Isopropyl Palmitate 4.2

Polyglyceryl-3 Dioleate 1 .14

Coco-Caprylate/Caprate 0.36

Sorbitan Sesquioleate 0.3 The wax or butter is added to the emulsifying composition and heated to slightly above its melting point to form the oily phase.

The aqueous phase was formed by mixing 5 parts by weight of glycerine, 1 part by weight of magnesium sulphate and a balance of water to form 100 parts by weight of resultant HIPE. The aqueous phase was heated to the same temperature as the oily phase and added drop- wise as described above.

The various waxes used are shown in Table 7. Table 7

The viscosity of the resultant HIPE using 0.5 weight percent wax was measured using a Brookfield Viscometer DV-E, spindle 94 at 10 rpm when measured at 25°C and shown in Table 7.

The stability of the resultant HIPEs was measured at times up to 3 weeks. The results are shown in Table 8. These results demonstrated that whilst it is possible to form a stable HIPE using the emulsion composition of the present invention, the presence of a wax in the final HIPE composition provides improved high temperature stability.

It can be seen that where the wax has a melting point of less than 50°C, the stability drops even at higher amounts of wax. Table 8

Example 9

Emulsifying compositions were produced to test stability using combinations of glycerine, 5 MgSC>4, and wax as set out in Table 7.

The following composition formula was used:

Isopropyl palmitate 4.5 parts

Polyglyceryl-3 Dioleate 1 .25 parts

Sorbitan Sesquioleate 0.25 parts

Isopropyl Myristate 2 parts

Polyglyceryl-3 beeswax as in Table 9

Glycerine as in Table 9

MgS0 ₄ as in Table 9

Water to 100 parts

15

The emulsions were formed in the same manner as for Example 8 above.

Table 9

Emulsions can be formed in the absence of MgSCU, glycerine and wax. However, the stability after a week is poor. It appears that the inclusion of the metal salt is particularly important to increasing the stability of the HIPE. Glycerine is less important for stability, but is useful for increasing heat stability and gives a better texture to the cream (better pick up, more shear thinning rheology).

Example 10

A high internal phase emulsion is formed using the following formulation:

Emulsifier composition 6%

Squalane 2%

Glycerine 5%

MgS04 1 %

Water 86%

The emulsifier composition used is formed from

Polyglyceryl-3 Dioleate 1 .25%

Sorbitan Sesquioleate 0.25%

Isopropyl palmitate 4.5% The HIPE is formed using the same method as in Example 1.

The HIPE was then tested using cryogenic transmission electron microscopy (cryo-TEM). The results are shown in Figure 1.

The electron microscopy grid is first glow discharged and the sample of the HIPE applied. As can be seen from Figure 1 , the oily phase can be seen as a thin darker line between the aqueous areas. The droplets are not round but are distorted, which is typical of a HIPE.

Example 1 1

Emulsifying compositions were produced to test stability using different particulate substances as set out in Table 10. The following composition formula was used:

Isopropyl palmitate 4.2 parts

Polyglyceryl-3 Dioleate 1 .15 parts

Coco-caprylate/caprate 0.35 parts

Sorbitan Sesquioleate 0.3 parts Isopropyl Myristate 2.0 parts

Hydrogenated vegetable wax 1 .0 parts

Glycerine 5.0 parts

MgS0 ₄ 1 .0 parts

Phenoxyethanol/Ethylhexylglycerin 0.5 parts

Zinc oxide see Table 10

Tapioca starch (Farmal 21 T) see Table 10

Water to 100 parts

The emulsions were formed in the same manner as for Example 8 above. The zinc oxide, tapioca starch and pheoxyethanol/ethylhexylglycerin were added after the emulsion was formed.

The emulsions were tested under different conditions. The stability was measured for 12 weeks at both 40°C and 50°C. The stability was also tested using a cycling test. Samples were held at -5°C for 24 hours and then 20°C for 24 hours. This constitutes one cycle. The samples were tested for three complete cycles and the stability checked. The stability test is used to check the robustness of a composition when subjected to temperature change.

Table 9

It can be seen that all emulsions showed good stability after 12 weeks at 40°C. However, the inclusion of particles improved the stability when cycling the temperatures between -5 and 20°C. The inclusion of both types of particle also improved stability after 12 weeks at 50°C.

The particles therefore appear to improve the stability of these high internal phase emulsions yet further.