CH649915A5 - COSMETIC COMPOSITION BASED ON AN AQUEOUS DISPERSION OF LIPID SPHERULES. - Google Patents

Description

The present invention relates to a cosmetic composition consisting of a dispersion of lipid spherules. Aqueous dispersions of this kind have already been described in French patent No. 2315991 filed on June 30, 1975.

The lipid spherules of these dispersions are characterized by their structure in sheets made up of two or more lipid layers separated from each other by layers of aqueous phase. They can thus be used to encapsulate, in the aqueous compartments comprised between the lipid layers, water-soluble active substances, for example pharmaceutical or cosmetic, and to protect them from external conditions.

The aforementioned French patent also describes a new process for preparing an aqueous dispersion of lipid spherules consisting, first of all, in bringing the lipids intended to constitute the concentric sheets of the spherules into contact with the aqueous solution to be encapsulated, the lipophilic / hydrophilic of the lipids chosen being such that the latter swell in water or in the aqueous phase to be encapsulated to form a planar lamellar phase, secondly, to add to the lamellar phase an aqueous solution intended to constitute the continuous external phase of the dispersion and, thirdly, to subject the whole to vigorous stirring to obtain a dispersion of spherules between the concentric sheets of which is trapped the aqueous phase to be encapsulated.

To form the concentric sheets of the spherules, it is possible, according to the teaching of the French patent considered, to use amphiphilic lipids or either ionic or nonionic lipids. Among the nonionic amphiphilic lipids, preference is given to:

- linear or branched polyglycerol ethers of respective formulas:

R-f OCH2CHOH - CH2) j- OH

and

R-f OCH2 — CH) j-OH CH2OH

n being an integer between 1 and 6, R being a linear or branched, saturated or unsaturated aliphatic chain of 12 to 30 carbon atoms, the hydrocarbon radicals of lanolin alcohols or the hydroxy-2-alkyl radicals of the α-diols to long chain;

- polyoxyethylenated fatty alcohols;

- esters of polyols, oxyethylenated or not and, in particular, polyoxyethylenated sorbitol esters;

- glycolipids of natural or synthetic origin, for example cerebrosides.

Among the cosmetic active substances which can be encapsulated in lipid spherules, the aforementioned French patent gives by way of example substances intended for the care of the coating.

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skin products such as humectants, artificial browning agents, skin coloring agents, water-soluble sunscreens, antiperspirants, deodorants, astringents, refreshing, tonic, healing, keratolytic, depilatory, water perfumed and extracts of animal or vegetable tissues.

It has been observed that the cosmetic compositions referred to above in the form of an aqueous dispersion of lipid spherules have the advantage, compared with conventional preparations in the form of an oil and water emulsion, of exhibiting a less aggressive effect and, as a result, cause less irritation when applied to the skin.

The present invention aims to describe a cosmetic composition based on an aqueous dispersion of lipid spherules making it possible to combine both the advantages of spherule dispersions and those resulting from the presence of cosmetic oils.

The subject of the present invention is therefore a cosmetic composition consisting of an aqueous dispersion of spherules composed of organized molecular layers between which an internal aqueous phase is encapsulated, these layers consisting of at least one nonionic amphiphilic lipid, characterized in that at least one oil is dispersed in the external aqueous phase which surrounds the spherules, said oil being taken from the group formed by esters of fatty acids and of polyols, in particular liquid triglycerides, and by esters of fatty acids and branched alcohols of formula R — COOR ', formula in which R represents the residue of a higher fatty acid containing from 8 to 20 carbon atoms and R' represents a branched hydrocarbon chain containing from 3 to 20 carbon atoms.

It is unexpectedly observed that the spherules of nonionic amphiphiles make it possible to stabilize the dispersion of oil in water without requiring the addition of a traditional emulsifying agent or causing the destruction of the spherules. However, it is known that the stability of an emulsion depends essentially on the presence of an emulsifier, the molecules of which will adsorb on the surface of the oil droplets, forming a sort of continuous membrane which prevents contact direct from two neighboring droplets, during a shock for example. Thus, in the present case, a person skilled in the art would have been led to think that the nonionic amphiphilic lipids of the spherules could certainly play the role of an emulsifier by being adsorbed on the surface of the oil droplets, but that this stabilization also had the effect of destroying the concentric sheets of the spherules. However, this is not the case and it is found, surprisingly, that the spherules of nonionic amphiphiles of the invention are capable of stabilizing a dispersion of at least one vegetable oil defined above in a phase external aqueous by dispersing around the oil droplets while maintaining their integrity.

In the patent of the United States of America No. 3957971, dispersions of spherules of ionic amphiphiles or liposomes used in the composition of cosmetic creams or lotions, that is to say water-in emulsions, are described. oil or oil-in-water. In the present invention, the spherules are composed not of ionic amphiphiles, but of nonionic amphiphiles. In addition, it has been found that the liposomes do not make it possible to stabilize a dispersion in water of a vegetable oil taken in the class referred to above, whereas, quite unexpectedly, the spherules of amphiphiles not ionic of the invention allow to stabilize such a dispersion.

The preparation of the cosmetic composition according to the invention is done in two stages: firstly, an aqueous dispersion of spherules is prepared from nonionic amphiphilic lipids by implementing either the process claimed in French patent N ° 2315991, or else the procedures described in French patent No. 2221122. In a second step, once the aqueous dispersion of spherules is produced, oil is especially added thereto. Then, by stirring, the oil is dispersed in the external aqueous phase.

Preferably, the cosmetic composition according to the invention contains from 2 to 10% of non-ionic amphiphilic lipid (s), constituting the walls of the spherules, and from 2 to 40% of dispersed oil (s) (s), these percentages being expressed by weight relative to the total weight of the composition. Advantageously, the relative weight proportion of non-ionic amphiphilic lipid (s) relative to the dispersed oil (or oils) is between 0.2: 1 and 1: 1.

The oils which can be incorporated into the composition according to the invention are taken from the group formed by esters of fatty acids and of polyols, in particular liquid triglycerides and esters of fatty acids and branched alcohols of formula R— COO — R ', formula in which R represents the remainder of a higher fatty acid containing from 8 to 20 carbon atoms and R' represents a branched hydrocarbon chain containing from 3 to 20 carbon atoms. Among the esters of fatty acids and polyols, mention may be made of sunflower, corn, soybean, squash, grapeseed, jojoba and glycerol tricaprocaprylate oils. Among the esters of higher fatty acids and branched alcohols, mention may be made of purcellin oil.

The cosmetic active substances of the composition according to the invention can be encapsulated inside or outside the spherules. Thus, in a preferred embodiment, the oily phase of the composition contains one or more liposoluble cosmetic substances. The latter are, during the preparation of the composition according to the invention, previously dissolved in the oil which is intended to be added to the dispersion of lipid spherules. Among these liposoluble active cosmetic substances, mention may in particular be made of sunscreen filters such as 2-ethylhexyl paradimyl-thylaminobenzoates or substances intended to improve the condition of dry or senile skin, in particular unsaponifiables such as unsaponifiables of soy, avocado, toco-pherols, vitamins E, F, antioxidants.

The dispersion of oil in water which constitutes the external medium of the dispersion of spherules may contain at least one additive, in particular a gelling agent or a perfume. The additive is added to the dispersion at the same time as the oil. The gelling agent can be introduced at a concentration varying between 0.1 and 2%, these percentages being expressed by weight relative to the total weight of the composition. Among the gelling agents which can be used, mention may be made of cellulose derivatives such as hydroxyethylcellulose; synthetic polymers; algae derivatives such as satiagum or natural gums such as tragacanth. It is preferred to use, as gelling agents, hydroxyethylcellulose, a mixture of carboxyvinyl acids commercially available under the name of Carbopol 940, satiagum or else the tragacanth.

The nonionic amphiphilic lipids which are intended to constitute the concentric sheets of the spherules in the cosmetic composition according to the invention are:

- linear or branched polyglycerol ethers or esters, of respective formulas:

R-f OCH2CHOH — CH2) j OH

and

R-f OCH2 — CH) gOH CH2OH

formulas in which n is a number between 2 and 6 and R represents a saturated, linear or branched aliphatic chain, comprising from 16 to 20 carbon atoms or the hydrocarbon radical of a lanolin alcohol;

- polyoxyethylenated sterols.

At the time of formation of the planar lamellar phase obtained by bringing the nonionic amphiphilic lipids into contact with the aqueous phase to be encapsulated, various auxiliary agents can be combined with said lipids in order to modify, for example, the permeability or the surface charge of the spherules. In this regard, mention may be made of the possible addition of long-chain alcohols and diols, sterols, in particular cholesterol and P-sitosterol, long-chain amines.

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chain and their quaternary ammonium derivatives, in particular didodeccyldimethylammonium bromide, hydroxyalkylamines, polyoxyethylenated fatty amines, esters of long chain amino alcohols and their salts and quaternary ammonium derivatives, phosphoric esters of fatty alcohols, in particular of diketylphos- phate, alkyl sulphates, for example sodium cetyl sulphate, certain polymers such as polypeptides and proteins.

In addition to the auxiliary agents listed above, a preservative can be added such as methyl parahydroxybenzoate for example.

The aqueous phase, whether internal or external, may contain a water-soluble cosmetic substance usually used for the care of the face, hands or body. Among these substances, mention may be made of humectants such as glycerin, sorbitol, pentaé-rythritol, inositol, pyrrolidonecarboxylic acid and its salts; artificial browning agents such as dihydroxyacetone, erythrulose, glyceraldehyde, γ-dialdehydes such as tarric aldehyde; skin coloring agents; sunscreens, antiperspirants, deodorants, astringents, refreshing, tonic, healing, keratolytic, depilatory, scented waters, extracts of animal or plant tissues, such as proteins, amniotic fluid, Polysaccharides, and antiseborrhoeic agents .

To better understand the object of the invention, several embodiments will now be described by way of purely illustrative and nonlimiting examples.

The preparation of the cosmetic formulations given in the examples below is carried out in two phases. In a first phase, an aqueous dispersion is produced according to the process described in French patent No. 2315991. The aqueous dispersion of lipid spherules is prepared from:

- a nonionic amphiphilic lipid;

- sterols such as cholesterol or p-sitosterol;

- possibly diketylphosphate;

- optionally active cosmetic substances of water-soluble nature, and

- demineralized water which may contain a preservative.

In a second phase, the oil is added, which is dispersed by intense mechanical stirring at room temperature, preferably at a temperature of about 40 ° C. It is during this second phase that may optionally incorporate liposoluble cosmetic substances, perfumes and / or gelling agents.

Example 1

Comparative tests between a cosmetic composition according to the invention and a cosmetic composition of known type.

Two strictly identical compositions A and B are prepared, with the difference that the preparation of composition B does not include a second phase of oil addition.

Composition A contains the following ingredients:

1 "Phase

- Nonionic amphiphilic lipid of formula:

R-f 00 ^ -0% OH

CH2OH

in which R is a hexadecyl radical and n has a mean statistical value equal to 3 3.8 g

- P-Sitosterol 3.8 g

- Diketylphosphate 0.4 g

- Methyl parahydroxybenzoate 0.3 g

- Demineralized water 66.7 g

2 Phase

25 g of sunflower oil are added to the above dispersion; the whole is subjected to mechanical stirring to obtain the final dispersion.

Cosmetic composition B is prepared in the same way but without the second phase of adding sunflower oil, the 25 g of oil then being replaced by an identical amount of demineralized water.

5 Cosmetic composition A is therefore distinguished from cosmetic composition B in that it contains 25% sunflower oil.

1. Measurements of the coefficient of friction of the skin during the plating of the cosmetic compositions A and B.

The coefficient of friction of the skin is measured during the spreading of cosmetic compositions A or B on the forearm of a subject using a feeler animated with a rotary movement; the evolution of the resisting torque is recorded at the level of the probe during its rotation on itself; the probe is applied at constant force (20 or 50 g).

The following results are obtained:

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Change in the coefficient of friction of the skin measured 15 min after application

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Under a force of 20 g

Under a force of 50 g

Composition B

+209

+245

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Composition A according to the invention (containing 25% sunflower oil)

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- 60

It is observed that composition B, that is to say the aqueous dispersion of lipid spherules which does not contain oil, appreciably increases the coefficient of friction of the skin, while composition A according to the invention, c that is to say a dispersion of spherules which contains oil, makes it possible to obtain an opposite effect. This significant reduction in the coefficient of friction of the skin reflects 40 on the cosmetic level the effect of softness provided by formulation A according to the invention.

2. Measurement of the modulus of elasticity of the human Stratum corneum carried out in vitro before and after application of the cosmetic compositions

.. A and B above.

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These measurements were carried out on a laboratory device intended to measure the elastic modulus of the skin. Such a laboratory device is described in French patent No. 78. 25149 applied for on August 31, 1978.

50 The experimental conditions are as follows:

relative humidity: 72% + 2

temperature: 30 ° C ± 0.2

amount of product applied: 5 mg / cm2 The following results are obtained:

Products tested

Average reduction in elastic modulus 1! 4 h after application (%)

Composition B Composition A according to the invention

0

+ 15

The above results show significantly the difference in plasticity of the cornea, depending on whether one applies a disper

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sion of spherules without oily phase or a dispersion of spherules with an oily phase.

Example 2

Body care fluid.

I "Phase

As indicated above, an aqueous dispersion of lipid spherules is produced from the following substances:

- Nonionic amphiphilic lipid of general formula:

R -f OCH2 - CH OH

CH2OH

in which R is a hexadecyl radical and n has a mean statistical value equal to 3 4.5 g

P-Sitosterol 4.5 g

Diketylphosphate 1.0 g

Methyl parahydroxybenzoate 0.3 g

Sodium salt of pyrrolidonecarboxylic acid 2.0 g

Demineralized water 56.5 g

2 Phase

The following substances are added to the dispersion of spherules obtained in the 1st phase:

Perfume 0.4 g

Sunflower oil 10.0 g Mixture of carboxyvinyl acids sold

under the name Carbopol 940 0.4 g

Triethanolamine 0.4 g

Demineralized water 20.0 g

Example 3

Facial care fluid.

1 "Phase

As indicated above, an aqueous dispersion of lipid spherules is produced from the following substances:

- Nonionic amphiphilic lipid of general formula:

R-f 0CH2 —CH) jOH

CH2OH

in which R is a hexadecyl radical and n has a value equal to 2 6.0 g

Cholesterol 1.6 g

Diketylphosphate 0.4 g

Methyl parahydroxybenzoate 0.3 g

Demineralized water 61.1g

2 Phase

The following substances are added to the dispersion of spherules obtained in the 1 "phase:

Perfume 0.2 g

Grapeseed oil 20.0 g Mixture of carboxyvinyl acids sold

as Carbopol 940 0.2 g

0.2 g triethanolamine

Demineralized water 10.0 g

Example 4

Hand care fluid.

1 "Phase

As indicated above, an aqueous dispersion of lipid spherules is produced from the following substances:

Polyoxyethylenated phytosterols (statistical distribution with an average value of 5) 6.0 g

Cholesterol 2.0 g

Methyl parahydroxybenzoate 0.3 g

Demineralized water 45.7 g

2 Phase

The following substances are added to the dispersion of spherules obtained in the 1st phase:

Perfume 0.2 g

Jojoba oil 25.0 g Mixture of carboxyvinyl acids sold

under the name of Carbopol 940 _ 0.4 g

Triethanolamine 0.4 g

Demineralized water 20.0 g

Example 5

Body care fluid.

F'Phase

As indicated above, an aqueous dispersion of lipid spherules is produced from the following substances:

- Nonionic amphiphilic lipid of general formula:

R -f OCH2 - CH) = - OH I "

CH2OH

in which R is a hexadecyl radical and n has a mean statistical value equal to 3 4.0 g

Cholesterol 4.0 g

Methyl parahydroxybenzoate 0.3 g

Demineralized water 45.5 g

2 'Phase

The following substances are added to the dispersion of spherules obtained in the 1st phase:

Perfume 0.4 g

Corn oil 25.0 g Mixture of carboxyvinyl acids sold

under the name Carbopol 940 0.4 g

Triethanolamine 0.4 g

Demineralized water 20.0 g

Example 6

Facial care fluid.

1 "Phase

As indicated above, an aqueous dispersion of lipid spherules is produced from the following substances:

- Nonionic amphiphilic lipid of general formula:

R -f OCH2 - CH) = OH

I "

ch2oh in which R is a hexadecyl radical and n has a mean statistical value equal to 30.95 g

P-Sitosterol 0.95 g

Dicetylphosphate 0.10 g

Methyl parahydroxybenzoate 0.30 g

Demineralized water 64.80 g

2 Phase

The following substances are added to the dispersion of spherules obtained in the 1st phase:

Perfume 0.4 g

Soybean oil 10.0 g

Soy unsaponifiables 2.0 g Hydroxyethylcellulose marketed under the name of Natrosol 250 HHR 0.5 g

Demineralized water 20.0 g

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Example 7

Sun care fluid.

1 "Phase

As indicated above, an aqueous dispersion of lipid spherules is produced from the following substances:

- Nonionic amphiphilic lipid of general formula: R -f OCH2 - CHW OH

I

ch2oh in which R is a hexadecyl radical and n has a mean statistical value equal to 3 3.6 g

P-Sitosterol 3.6 g

Didodecyldimethylammonium bromide 0.8 g

Methyl parahydroxybenzoate 0.3 g

Demineralized water 45.9 g

2 Phase

The following substances are added to the dispersion of spherules obtained in the 1st phase:

Perfume 0.4 g

Pumpkin oil 22.0 g

2-ethylhexyl paradimethylaminobenzoate 3.0 g

Tragacanth 0.4 g

Demineralized water 20.0 g

Example 8

Hand care fluid.

1 "Phase

As indicated above, an aqueous dispersion of lipid spherules is produced from the following substances:

- Nonionic amphiphilic lipid of general formula:

R -f OCH2 — CH) = - OH CH2OH

in which R is a hexadecyl radical and n has a mean statistical value equal to 3 3.8 g

P-Sitosterol 3.8 g

Diketylphosphate 0.4 g

Methyl parahydroxybenzoate 0.3 g

Glycerin 3.0 g

Demineralized water 42.5 g

2 Phase

The following substances are added to the dispersion of spherules obtained in the 1st phase:

Perfume 0.2 g

Purcellin oil 25.0 g

Satiagum - 1.0 g

Demineralized water 20.0 g

Example 9

Body care fluid.

1 "Phase

As indicated above, an aqueous dispersion of lipid spherules is produced from the following substances:

- Nonionic amphiphilic lipid of general formula:

R -f OCH2 — CH) = - OH

CH2OH

in which R is a hexadecyl radical and n has a mean statistical value equal to 3 3.8 g

P-Sitosterol 3.8 g

Diketylphosphate 0.4 g

Methyl parahydroxybenzoate 0.3 g

Demineralized water 60.5 g

2 Phase

The following substances are added to the dispersion of spherules obtained in the 1st phase:

Perfume 0.4 g

Glycerol tricaprocaprylate 10.0 g Mixture of carboxyvinyl acids marketed

under the name Carbopol 940 0.4 g

Triethanolamine 0.4 g

Demineralized water 20.0 g

Example 10

Face care cream.

1 "Phase

As indicated above, an aqueous dispersion of lipid spherules is produced from the following substances:

- Nonionic amphiphilic lipid of general formula:

R-f OCH2 - CH) = - OH CH2OH

in which R is a hexadecyl radical and n has a mean statistical value equal to 3 3.8 g

P-Sitosterol 3.8 g

Diketylphosphate 0.4 g

Preservative 0.3 g

Demineralized water 47.6 g

2 Phase

The following substances are added to the dispersion of spherules obtained in the 1st phase:

Sunflower oil 35.0 g

Perfume 0.6 g Mixture of carboxyvinyl acids sold

as Carbopol 940 0.2 g

0.2 g triethanolamine

Demineralized water 8.1 g

It is understood that the embodiments described above are in no way limiting and may give rise to any desirable modifications without departing from the scope of the invention.

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Claims (13)

649,915 1. Cosmetic composition consisting of an aqueous dispersion of spherules composed of organized molecular layers between which an internal aqueous phase is encapsulated, these layers consisting of at least one nonionic amphiphilic lipid, characterized in that at least one oil is dispersed in the external aqueous phase which surrounds the spherules, said oil being taken from the group formed by esters of fatty acids and polyols and by esters of fatty acids and branched alcohols of formula R — COOR ', formula in which R represents the remainder of a higher fatty acid comprising from 8 to 20 carbon atoms and R 'represents a branched hydrocarbon chain containing from 3 to 20 carbon atoms. 2. Composition according to claim 1, characterized in that the esters of fatty acids and of polyols are liquid triglycerides. 2 3. Composition according to claim 1, characterized in that the esters of fatty acids and of polyols are taken from the group formed by oils of sunflower, corn, soy, squash, grapeseed, jojoba and glycerol trieaprocaprylate. 4. Composition according to claim 1, characterized in that the ester of higher fatty acids and branched alcohols is purcellin oil. 5. Composition according to one of claims 1 to 4, characterized in that it contains from 2 to 10% of non-ionic amphiphilic lipid (s), constituting the walls of the spherules, and of 2 at 40% dispersed oil (s), these percentages being expressed by weight relative to the total weight of the composition, the relative weight proportion of non-ionic amphiphilic lipid (s) relative to the dispersed oil (or oils) being between 0.2: 1 and 1: 1. 6. Composition according to one of claims 1 to 5, characterized in that the external phase contains 0.1 to 2% by weight of gelling agents), these percentages being expressed by weight relative to the total weight of the composition. 7. Composition according to claim 6, characterized in that the gelling agent is taken from the group formed by cellulose derivatives, synthetic polymers, algae derivatives or natural gums. 8. Composition according to one of claims 1 to 7, characterized in that the external phase contains at least one perfume and / or one or more liposoluble cosmetic substances. 9. Composition according to claim 8, characterized in that the liposoluble cosmetic substance constitutes a sunscreen filter, a substance intended to improve the condition of dry or senile skin or an antioxidant. 10. Composition according to one of claims 1 to 9, characterized in that the nonionic amphiphilic lipids, which constitute the walls of the spherules, are: - linear or branched polyglycerol ethers or esters of respective formulas: R ir OCH2CHOH -CH ^ OH and R-fOCH2 — CHfeOH CH2OH formulas in which n is a number between 2 and 6 and R represents a saturated, linear or branched aliphatic chain, comprising from 16 to 20 carbon atoms or the hydrocarbon radical of a lanolin alcohol; - polyoxyethylenated sterols. 11. Composition according to claim 10, characterized in that the nonionic amphiphilic lipids are associated with auxiliary agents taken from the group formed by long chain alcohols and diols, steriles, in particular cholesterol and P-sitosterol, long chain amines and their quaternary ammonium derivatives, hydroxyalkylamines, polyoxyethylenated fatty amines, esters of long chain amino alcohols and their quaternary ammonium salts and derivatives, polymers, phosphoric esters of fatty alcohols, in particular diketylphosphate. 12. Composition according to one of claims 1 to 11, characterized in that the internal aqueous phase or the external phase contains at least one water-soluble cosmetic substance. 13. Composition according to claim 12, characterized in that the water-soluble cosmetic substance is taken from the group formed by humectants such as glycerin, sorbitol, pentaerythritol, inositol, pyrrolidonecarboxylic acid and its salts; artificial browning agents such as dihydroxyacetone, erythrulose, glyceraldehyde, γ-dialdehydes such as tartaric aldehyde; skin coloring agents; sun filters; antiperspirants, deodorants, astringents, refreshing, tonic, healing, keratolytic, depilatory products; scented waters, extracts from animal or plant tissues, such as proteins, Polysaccharides, amniotic fluid, and antiseborrheic agents.