Stable emulsion containing unesterified tocopherol and / or unesterified tocotrienol, and process for its preparation

Abstract

------ Stable emulsion containing unesterified tocopherol and / or unesterified tocotrienol, and process for its preparation This emulsion comprises per 100 parts by mass of (A)+(B): (A) 15 to 35 parts by mass of an oily phase based on tocopherol and / or tocotrienol, containing at least one lipophilic emulsifier having an HLB of 5 to 9, chosen from fatty acid esters and carbohydrates; fatty acid esters and glycerol; and phospholipids, said lipophilic emulsifier not being a polyethoxylated compound or a polyether compound; and (B) 65 to 85 parts by mass of an aqueous phase containing at least one hydrophilic emulsifier having an HLB of at least 10, chosen from partially esterified dialiphatic polyacids, optionally associated with non-esterified aliphatic polyacids; vegetable gums; and phospholipids, said hydrophilic emulsifier not being a polyethoxylated compound or a polyether compound.

Description

Title of the invention: Stable emulsion containing non-esterified tocopherol and / or non-esterified tocotrienol, and process for its preparation

[0001] The present invention relates to a stable cosmetic emulsion containing non-esterified tocopherol and / or non-esterified tocotrienol.

[0002] Under the name tocopherol, specialists designate several vitamins of type E. We know tocopherol and its unsaturated analogue, tocotrienol, and their four isomers: α, β, γ and δ. The most widespread antioxidant in nature is α-tocopherol. The most powerful antioxidant is tocotrienol.

[0003] The moisturizing, anti-oxidant and anti-UV properties of tocopherols and tocotrienols have been well known to specialists for several years and there have naturally already been attempts to take advantage of them by incorporating tocopherol into cosmetic preparations.

[0004] It has thus been established that tocopherol can penetrate rapidly through the skin and concentrate near the sebaceous glands, and that topical application of tocopherol can protect the skin against damage caused by UV light and against peroxidation of skin lipids, and also reduce fine lines and wrinkles and slow down the skin aging process.

[0005] However, the application of pure tocopherol to the skin cannot be considered since it is a very viscous product, and which also leaves the skin greasy and sticky.

[0006] It is therefore desirable to formulate tocopherol and / or tocotrienol in the form of an emulsion.

[0007] Specialists have already proposed numerous cosmetic emulsions containing tocopherol. Such emulsions are conventionally formed by the combination of an oily phase containing tocopherol and an aqueous phase. These two phases are made compatible thanks to a pair of emulsifying agents, namely, on the one hand, a lipophilic emulsifier having a low HLB (Hydrophilic / Lipophilic Balance) contained in the oily phase and, on the other hand, a hydrophilic emulsifier having a high HLB contained in the aqueous phase.

[0008] However, the emulsions currently on the market generally contain only a very small proportion of tocopherol, often between 0.1 and 1% by mass, since this is a product that is difficult to emulsify: in fact, when tocopherol oils are added to emulsions, they decompose rapidly.

[0009] For this reason, tocopherol emulsions currently on the market contain as a rule a very high proportion of emulsifiers up to 100% by weight relative to tocopherol.

[0010] In addition to this physical instability of tocopherol-based emulsions, there is a chemical instability resulting from the fact that tocopherols contain a phenolic group which can be oxidized relatively easily by air to give oxidation products.

[0011] It should be noted that the oxidation of a finely dispersed emulsion of tocopherol is significantly easier than the oxidation of pure, undispersed tocopherol because the contact surface with the oxygen in the air is much greater.

[0012] For this reason, tocopherol emulsions currently on the market generally contain tocopherol acetate.

[0013] For example, acetate, succinate (the sodium salt of which is soluble in water), linolenate, nicotinate, polyethylene glycol ether of tocopherol and its succinic ester (the sodium salt of which is soluble in water), or tocopherol phosphate (the sodium salt of which is also soluble in water) are widely used as pharmaceutical products or additives or as cosmetic additives given their activity as vitamin E.

[0014] Esters such as tocopherol acetate, succinate, linoleate, linolenate or retinoate are particularly widely used in cosmetic preparations given their stability and ease of incorporation into formulations, in particular as "active" fatty substances, emollients, antioxidants, moisturizers or lubricants. They are thus found in many anti-aging products where they protect the skin from damage by free radicals, or as an agent preventing the rancidity of fatty substances (in oils, serums or other balms, etc.).

[0015] However, it has been established that tocopherol esters such as acetate, succinate, linoleate, linolenate or retinoate have low or negligible activity, and that the moisturizing and antioxidant activity of the compositions containing them is due essentially to the fraction of free tocopherol formed by hydrolysis. However, the hydrolysis of the esters, in particular of tocopherol acetate, is almost zero on the superficial layers of the skin (stratum corneum) and very slow in the deep layers of the epidermis: in fact, in twelve hours, it is only around 50%. This difference in activity between free tocopherol on the one hand and tocopherol esters on the other hand has, for example, been studied in the literature.

[0016] In view of this situation, it is desirable to be able to have stable emulsions containing a significant proportion not of tocopherol esters, but of its active form, namely unesterified tocopherol. The same applies to tocotrienol.

[0017] It is in fact in this form that tocopherol exhibits antioxidant activity. and remarkable protection on the skin, particularly against the carcinogenic action of the sun's ultraviolet rays.

[0018] Such emulsions would be all the more advantageous since recent studies have demonstrated the inhibitory and protective action of non-esterified tocopherol with respect to the carcinogenesis of skin irritation by UVB and have even suggested that tocopherol acetate not only has no preventive action, but on the contrary seems likely to promote photocarcinogenesis.

[0019] The present invention therefore aims to meet this expectation by proposing a stable emulsion containing a significant proportion of non-esterified tocopherol / tocotrienol.

[0020] The present invention therefore relates to a stable emulsion for application to the skin of tocopherol and / or tocotrienol, characterized in that it comprises, per 100 parts by mass of (A)+(B): A. 15 to 35 parts by mass of an oily phase based on tocopherol and / or tocotrienol, containing at least one lipophilic emulsifier having an HLB of 5 to 9, chosen from fatty acid esters and carbohydrates; fatty acid esters and glycerol; and phospholipids, said lipophilic emulsifier not being a polyethoxylated compound or a polyether compound; and B. 65 to 85 parts by mass of an aqueous phase containing at least one hydrophilic emulsifier having an HLB of at least 10, chosen from partially esterified dialiphatic polyacids, optionally combined with non-esterified aliphatic polyacids; vegetable gums; and phospholipids, said hydrophilic emulsifier not being a polyethoxylated compound or a polyether compound.

[0021] Part (A) may be present from 18 to 31 parts by mass and part (B) from 69 to 82 parts by mass per 100 parts by mass of (A)+(B).

[0022] The lipophilic emulsifier(s) may have an HLB of 6 to 7.

[0023] Tocopherol / tocotrienol may be introduced in at least one of the forms α, β, γ and δ, being in particular α-tocopherol, in particular α-tocopherol.

[0024] The tocopherol / tocotrienol may be present in the oil phase at a rate of 40 to 96 parts by mass and the lipophilic emulsifier(s) may be present at a rate of 1 to 8 parts by mass.

[0025] The oily phase may contain another oily substance chosen from vegetable oils that are not very sensitive to oxidation such as jojoba oil, sweet almond oil, argan oil, hazelnut oil, castor oil and apricot oil.

[0026] In particular: - the fatty acid and carbohydrate esters included in the definition of lipophilic emulsifier are chosen from sucrose monostearate and sucrose distearate; - the fatty acid and glycerol esters included in the definition of lipophilic emulsifier are chosen from glycerol monostearate and glycerol distearate; - the phospholipids included in the definition of lipophilic emulsifier are chosen from egg lecithin, soy lecithin and sunflower lecithin.

[0027] The emulsion may also comprise, in the oily phase, at least one additional liposoluble compound chosen in particular from: - antioxidants such as lycopene and coenzyme Q10; - skin conditioning agents such as fat-soluble amino acids and their derivatives such as phenylalanine and tyrosine; fat-soluble vitamins and their derivatives such as beta-carotene and retinol; and - perfuming agents such as vanilla oleoresin and essential oils,

[0028] in particular up to 40 parts by mass.

[0029] The hydrophilic emulsifier(s) may be present in the aqueous phase at a concentration of 0.4 to 3% by mass of the aqueous phase.

[0030] In particular: - the partially esterified polyacids, where appropriate associated with non-esterified aliphatic polyacids, falling within the definition of the hydrophilic emulsifier are chosen from emulsifiers of the carbomer series, such as the poly(acrylic acid / decyl acrylate / tri-acontane acrylate) copolymer; - the vegetable gums included in the definition of hydrophilic emulsifier are chosen from xanthan gum, guar gum; - the phospholipids included in the definition of hydrophilic emulsifier are chosen from phosphatidylserine, lysophosphatidylcholine and / or phosphatidylinositol; and - mono-, di- or polysaccharides partially esterified by fatty acids falling within the definition of hydrophilic emulsifier are chosen from sucrose monopalmitate and sucrose laurate.

[0031] The emulsion may also comprise, in the aqueous phase, at least one additional water-soluble compound chosen in particular from: - humectants such as urea; saccharides; polyols such as butylene glycol, glycerol, propylene glycol, sorbitol, xylitol and maltitol; - antioxidants such as black tea extract; cinnamon extract; astaxanthin; resveratrol and flavonoids such as hesperidin; - skin conditioning agents such as water-soluble amino acids and their derivatives such as glutamine and carnosine; water-soluble vitamins and their derivatives such as ascorbic acid, ascorbyl phosphate, nicotinamide and panthenol; α-hydroxy acids; sodium pyroglutamate; - pH regulators such as salts like sodium citrate; and - water-soluble polymers,

[0032] in particular up to 40 parts by mass.

[0033] The emulsion may also comprise a strong base chosen from sodium or potassium hydroxide or a ternary or quaternary amine, in particular present in an amount of 0.02 to 0.1 part by mass per 100 parts by mass of (A)+(B).

[0034] The emulsion may have an acidic pH, in particular from 4.5 to 5.5.

[0035] The emulsion can be in the form of a milk, a cream, a mousse or a spray.

[0036] The emulsions according to the present invention can be used for the treatment of the skin topically on the face, on the hands or on the body, and have a remarkable power of protection of the skin against attacks resulting from free radicals formed under the action of solar radiation, UV radiation, ozone, peroxides and effluents.

[0037] It has also been observed that the emulsions according to the present invention are not irritating to the most sensitive parts of the body, and also enhance the appearance of the skin by promoting its hydration, have a calming effect by soothing irritated or sensitive skin, and combat the oxidative phenomena responsible for skin aging by protecting it, leaving a pleasant and comfortable sensation. In addition to its cosmetic application, this type of emulsion can have medical applications such as the reduction of minor skin irritations such as diaper rash, superficial skin burns such as those due to radiotherapy, relief of skin itching in atopic skin, and healing.

[0038] The present invention also relates to a process for manufacturing an emulsion as defined above, characterized in that it comprises the following steps: - the lipophilic emulsifier(s) are dissolved in tocopherol and / or tocotrienol, where appropriate under heating and / or under an inert atmosphere and where appropriate with the other oily substance and / or the additional liposoluble compound(s); - the hydrophilic emulsifier(s) are dispersed in water, in particular distilled or demineralized water or a hydrosol, which has been brought to the boil to release the dissolved air, where appropriate with the compound(s)

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045] additional water-soluble(s); and - the products obtained in each of the previous steps are mixed with vigorous stirring until the desired emulsion is obtained, where appropriate with the addition of a basic aqueous solution such as an aqueous sodium hydroxide solution at 5 - 10% by mass to the oily phase obtained and / or to the aqueous phase obtained and / or to the mixture of these two phases to neutralize the polyacids which may be present therein, where appropriate with dissolution, in the boiling water, of an electrolyte, such as a salt of a strong acid and a strong base, for example sodium or potassium chloride or sulfate, where appropriate with the addition of a non-ionic gelling agent to the mixture of the oily and aqueous phases, in particular for 0.3 to 1.5% in the aqueous phase. The present invention also relates to the use of the emulsion as defined above or as prepared as indicated above to constitute or enter into the composition of cosmetic products. The following examples illustrate the present invention without, however, limiting its scope. In these examples: - the lipophilic emulsifier mono- / di-stearate of sucrose of HLB 6 is that marketed by the Sisterna Company under the name “SP30-C”; - EH1 is the hydrophilic copolymer emulsifier poly(acrylic acid / decyl acrylate / triacontane acrylate) marketed by BP Goodrich under the name “Premulin® TR-1”; - EH2 is the hydrophilic emulsifier copolymer of acrylic acid and an alkyl acrylate with 10 to 30 carbons marketed by Lubrizol Company under the name “Pemulen® TR-1”; - the hydrophilic emulsifier sucrose palmitate having an HLB of 16 is that marketed by the Sisterna Company under the name “PS750-C”; - the sodium ascorbyl phosphate antioxidant is the one marketed by DSM-firmenich Personal Care under the name “Stay-C® 50”; - all percentages indicated are by mass unless otherwise stated. The stability of the emulsion was checked under different storage conditions at room temperature (protected from light or exposed to light), +4°C in a refrigerator, +40°C and +50°C in an oven. - The evaluation of organoleptic characteristics (appearance, color and odor) is carried out by eye. - The pH is measured using a Mettler Toledo Seven multi pH meter. - Viscosity is measured with a Brookfield DV. - Weight is measured with an Ohaus scale. - Photos are taken in a light box to ensure uniform and comparable brightness from one test to another.

[0046] The measurements are carried out at room temperature at T0, 1 week, 2 weeks, 1 month, 2 months and 3 months.

[0047] The results obtained made it possible to validate the stability of the emulsion for 24 months at room temperature.

[0048] The physical stability of the emulsions was controlled by the so-called dissolution method, by diluting a given quantity of the emulsion, for example, with 10 or 100 volumes of distilled water at pH 7 and observing the emulsion for the time necessary for a higher oily phase to appear.

[0049] Example 1: Cream formed from an emulsion

[0050] Formulation: Ingredients Quantity (g) Percent Total Percent A + B Oil Phase A Da-Tocopherol 800 76.19% 28.97% Jojoba Oil 200 19.05% SP30-C 50 4.76% Water Phase B Distilled Water 2500 97.12% 71.03% EH2 20 0.78% Dehydroacetic Acid 4 0.16% Stay-C® 50 50 1.94% 10% NaOH 10 -

[0051] 1 - Preparation of an oily phase

[0052] 800g of Da-tocopherol with a purity greater than 90% by mass was mixed with 200g of jojoba oil and 50g of sucrose mono- / di-stearate and this mixture was heated to 60°C until it was homogeneous.

[0053] 2 - Preparation of an aqueous phase

[0054] 2500 mL of distilled water was heated to reflux and then cooled to 35°C. 20 g of EH2 was dispersed therein with stirring for 30 min, then 4 g of dehydroacetic acid and 50 g of sodium ascorbyl phosphate were added.

[0055] 3 - Preparation of the desired emulsion

[0056] With vigorous stirring, the oily phase thus obtained was added to the aqueous phase. thus obtained and stirring was continued for 30 min.

[0057] 10g of a 10% aqueous NaOH solution was then added and stirring of the resulting mixture continued for 2h.

[0058] The emulsion obtained showed stability at room temperature for 2 years.

[0059] Example 2: Cream formed from an emulsion

[0060] Formulation: Ingredients Quantity (g) Percent Total Percent A + B Oil Phase A Da-Tocopherol 500 47.62% 28.81% Jojoba Oil 500 47.62% SP30-C 50 4.76% Water Phase B Distilled Water 2500 96.38% 71.19% Dehydroacetic Acid 4 0.15% Stay-C® 50 50 1.93% Guar Gum 20 0.77% PS750-C 20 0.77% 10% NaOH 10 -

[0061] 1 - Preparation of an oily phase

[0062] 500g of Da-tocopherol of purity greater than 90% was mixed with 500g of jojoba oil and 50g of sucrose mono- / di-stearate and this mixture was heated to 60°C until homogeneous, then cooled to 35°-40°C.

[0063] 2 - Preparation of an aqueous phase

[0064] 2500 mL of distilled water was heated to reflux and then cooled to 35°C. 20 g of sucrose palmitate was dispersed therein with stirring for 30 min, then 4 g of dehydroacetic acid, 50 g of sodium ascorbyl phosphate and 20 g of guar gum were added.

[0065] 3 - Preparation of the desired emulsion

[0066] With vigorous stirring, the oily phase thus obtained was added to the aqueous phase thus obtained and stirring was continued for 30 min.

[0067] 10g of a 10% by mass aqueous NaOH solution was then added and stirring of the resulting mixture continued for 2h.

[0068] The emulsion obtained showed stability at room temperature for 2 years.

[0069] Example 3: High viscosity cream formed from an emulsion

[0070] Formulation: Ingredients Quantity (g) Percent Total Percent A + B Oil Phase A Da-Tocopherol 1000 90.74% 25.35% SP30-C 40 3.63% Beta-Carotene 30 2.72% Phenylalanine 20 1.81% Vanilla Oleoresin 8 0.73% Dehydroacetic Acid 4 0.36% Water Phase B Distilled Water 3000 92.45% 74.65% EH1 20 0.62% Stay-C® 50 50 1.54% Urea 100 3.08% Nicotinamide 30 0.92% Sodium Citrate 25 0.77% Camosine 20 0.62% 10% NaOH 32 -

[0071] 1 - Preparation of an oily phase

[0072] 1000g of Da-tocopherol of purity greater than 90% was mixed with 40g of sucrose mono- / di-stearate and 4g of dehydroacetic acid, and this mixture was heated at 60°C until homogeneous, i.e. for about 1 hour, then cooled to 35°-40°C.

[0073] 2 - Preparation of an aqueous phase

[0074] 3000 mL of distilled water was heated to reflux and then cooled to 35°C. 20 g of EH1 was dispersed therein with stirring.

[0075] 3 - Preparation of the desired emulsion

[0076] With vigorous stirring, the oily phase thus obtained was added to the aqueous phase thus obtained and stirring was continued for 30 min.

[0077] 32g of a 10% by mass aqueous NaOH solution was then added and stirring of the resulting mixture continued for 1h.

[0078] 50g of sodium ascorbyl phosphate, 100g of urea, 30g of nicotinamide, 30g of [3-carotene, 25g of sodium citrate, 20g of phenylalanine, 20g of camosine and 8g of vanilla essential oil were then added and stirred for 1h.

[0079] The emulsion obtained showed stability at room temperature for more than 2 years old.

[0080] Example 4: Low viscosity fluid emulsion

[0081] Formulation: Ingredients Quantity (g) Percentage Total percentage A + B Oil phase A Da-tocopherol 1000 95.69% 20.63% SP30-C 40 3.83% Dehydroacetic acid 5 0.48% Aqueous phase B Distilled water 4000 99.50% 79.37% EH1 20 0.50% 10% NaOH 40 -

[0082] 1 - Preparation of an oily phase

[0083] 1000g of Da-tocopherol with a purity greater than 98.5% was mixed with 40g of sucrose mono- / di-stearate and 5g of dehydroacetic acid and this mixture was heated to 60°C until homogeneous, then cooled to 25°-30°C.

[0084] 20g of a 10% by mass NaOH solution was added and the mixture was stirred vigorously for 2h.

[0085] 2 - Preparation of an aqueous phase

[0086] 4000 mL of distilled water was heated to reflux and then cooled to 35°C. 20 g of EH1 was dispersed therein with stirring, then 20 g of a 10% aqueous NaOH solution was added to neutralize the polyacids.

[0087] 3 - Preparation of the desired emulsion

[0088] With vigorous stirring, the aqueous phase thus obtained was added to the oily phase thus obtained and stirring was continued for 30 min.

[0089] The emulsion obtained showed stability at room temperature for more than 2 years.

[0090] Example 5: Cream absorbing UV radiation (fUVA and UVB)

[0091] Formulation: Ingredients Quantity (g) Percentage Total percentage A + B Oil Phase A Da-Tocopherol 1000 87.70% 29.65% SP30-C 80 7.02% Phenylalanine 30 2.63% Lycopene 0.20 0.02% Tyrosine 30 2.63% Aqueous Phase B Distilled Water 1800 66.54% 70.35% EH2 15 0.55% Dehydroacetic Acid 10 0.37% Stay-C® 50 50 1.85% Xanthan Gum 30 1.11% Black Tea Extract (ex 5) 800 29.57% Astaxanthin 0.20 0.01% 10% NaOH 5% NaOH 15 21.08 -

[0092] 1 - Preparation of a black tea extract

[0093] 2 kg of black tea (Camellia sinensis) was dispersed in 2.5 L of distilled water and brought to gentle reflux for 10 min. It was filtered hot through a filter press, and the leaves were rinsed with 500 mL of boiling water. The filtrate was concentrated to 600 g. 200 g of glycerol and 8 g of xanthan gum were added to the filtrate. The mixture was stirred at 60 °C for 30 min.

[0094] 2 - Preparation of an aqueous phase

[0095] In a 5L reactor equipped with a stirrer and a thermometer and under nitrogen, 1800 mL of distilled water heated to reflux for 10 min., then cooled to 40°C, 30g of xanthan gum, 15g of EH2, 50g of sodium ascorbyl phosphate and 10g of dehydroacetic acid were added, and the mixture was stirred to obtain a dispersion.

[0096] 3 - Preparation of an oily phase

[0097] In a 2L reactor, equipped with a stirrer and a thermometer and under nitrogen, 1000g of tocopherol with a purity greater than 90% and 80g of sucrose mono- / di-stearate and 20 mL of a 5% aqueous NaOH solution were added. The mixture was heated to 60°C until a homogeneous solution was obtained.

[0098] 4 - Preparation of the desired cream

[0099] The oily phase was poured into the aqueous phase with vigorous stirring and heated to 60°C for 30 min. Cooled to room temperature and added 15g of 10% aqueous NaOH solution, and stirred vigorously for 30 min. Added 200mg of astaxanthin and 200mg of lycopene, 30g of phenylalanine and 30g of tyrosine and stirred for 10 min, then added 800g of previously prepared black tea extract. The mixture was stirred for 50 min.

[0100] This emulsion was stable at room temperature for more than 2 years.

[0101] Example 6: Cream absorbing UV radiation (UVA and UVB)

[0102] Formulation: Ingredients Quantity (g) Percent Total Percent A + B Oil Phase A Da-Tocopherol 1000 91.22% 28.57% SP30-C 60 5.47% Phenylalanine 30 2.74% Vanilla Oleoresin 6 0.55% Lycopene 0.20 0.02% Water Phase B Distilled Water 1800 65.69% 71.43% PS750-C 15 0.55% Dehydroacetic Acid 10 0.36% Stay-C® 50 50 1.82% Xanthan Gum 15 0.55% Urea 50 1.82% Black Tea Extract (ex 6) 800 29.19% Astaxanthin 0.20 0.01% 10% NaOH 5% NaOH 10 31.61 -

[0103] 1 - Preparation of a black tea extract

[0104] The procedure was as in point 1 of Example 5 except that propylene glycol was used instead of glycerol and 50g of urea and 50g of ascorbic acid were added at the end of the preparation.

[0105] 2 - Preparation of an aqueous phase

[0106] In a 5L reactor equipped with a stirrer and a thermometer and under nitrogen, 1800 mL of distilled water was added, heated to reflux for 10 min. then cooled to 40°C, 15g of xanthan gum, 15g of sucrose palmitate, 50g of sodium ascorbyl phosphate, 50g of urea and 10g of dehydroacetic acid, and stirred to obtain a homogeneous dispersion.

[0107] 3 - Preparation of an oily phase

[0108] In a 2L reactor, equipped with a stirrer and a thermometer and under nitrogen, 1000g of tocopherol with a purity greater than 90% and 60g of sucrose mono- / di-stearate and 30 mL of a 5% aqueous NaOH solution were added. The mixture was heated to 60°C until a homogeneous solution was obtained.

[0109] 4 - Preparation of the desired cream

[0110] The oil phase was poured into the aqueous phase with vigorous stirring and heated at 60°C for 30 min. It was cooled to room temperature and 10g of a 10% aqueous NaOH solution was added, and stirred vigorously for 30 min. 200 mg of astaxanthin and 200 mg of lycopene were added and stirred for 10 min, then 800g of the previously prepared tea extract was added. The mixture was stirred for 50 min, then 6g of vanilla extract was added.

[0111] Samples of this emulsion placed in glass containers and closed with polyethylene stoppers were analyzed regularly by the HPLC method. After 12 months, the amount of tocopherolquinone formed is less than 2%.

[0112] This emulsion was stable at room temperature for more than 2 years.

[0113] Example 7: Preparation of a cream with high protection against UV radiation

[0114] Formulation: Ingredients Quantity (g) Percentage Total percentage A + B Oil phase A Da-tocopherol 1000 93.46% 25.06% SP30-C 60 5.61% Vanilla oleoresin 6 0.56% Dehydroacetic acid 4 0.37% Aqueous Phase B Distilled Water 2000 62.50% 74.94% EH1 20 0.63% Dehydroacetic Acid 10 0.31% Stay-C® 50 50 1.56% PS750-C 20 0.63% Urea 50 1.56% Black Tea Extract (ex 5) 800 25.00% Cinnamon Extract 250 7.81% 10% NaOH 20 -

[0115] 1 - Preparation of a cinnamon extract

[0116] 50g of cinnamon was dispersed in 300g of propylene glycol and heated at 100°C for 30 min. It was filtered under pressure to obtain 250g of a brick-red colored solution.

[0117] 2 - Preparation of an oily phase

[0118] 1000g of Da-tocopherol of purity greater than 90% was mixed with 60g of sucrose mono- / di-stearate, 4g of dehydroacetic acid and this mixture was heated to 60°C until it was homogeneous.

[0119] 3 - Preparation of an aqueous phase

[0120] 2000mL of distilled water was heated to reflux and cooled to 35°C. 20g of EH1 and 20g of sucrose palmitate were dispersed therein with stirring, then the dispersion was heated to 60°C with vigorous stirring, and cooled to 40°C.

[0121] 4 - Preparation of the desired cream

[0122] The oily phase was added to the aqueous phase with vigorous stirring for 10 min. An aqueous solution of 20 g of 10% NaOH was added and the mixture was vigorously stirred for 10 min. 250 g of the previously prepared cinnamon extract and 800 g of the black tea extract prepared in Example 5 were added with stirring. Stirring was continued and 50 g of sodium ascorbyl phosphate, 50 g of urea, 10 g of dehydroacetic acid and 6 g of natural Bourbon vanilla essence were added.

[0123] For an accelerated verification of the stability of the emulsion, a 10g fraction of the emulsion was taken, diluted under stirring with 90mL of distilled water and neutralized to pH 7. The emulsion was examined regularly. After 60 days, it remained homogeneous.

[0124] This emulsion was stable at room temperature for 2 years. Example 8

[0125] A stability test was carried out with the emulsion of Example 1 and a comparative emulsion with an emulsion identical to that of the Example except that the lipophilic emulsifier used is a glyceryl polyolivate-4 / polyricinoleate mixture marketed by the Hallstar Company under the name Olivem® 2090 and having an HLB of between 1 and 4.

[0126] The stability test was conducted under the following conditions: Room temperature in the dark; Room temperature under natural light; Refrigerator at 4°C; Oven at 40°C; Oven at 50°C.

[0127] After one month, the samples of Example 1 are stable under all conditions. After one week, the samples of the comparative emulsion show a phase shift under all conditions.

Claims

Claims

1. - Stable emulsion for application to the skin of tocopherol and / or tocotrienol, characterized in that it comprises, per 100 parts by mass of (A)+(B): A. 15 to 35 parts by mass of an oily phase based on tocopherol and / or tocotrienol, containing at least one lipophilic emulsifier having an HLB of 5 to 9, chosen from fatty acid esters and carbohydrates; fatty acid esters and glycerol; and phospholipids, said lipophilic emulsifier not being a polyethoxylated compound or a polyether compound; and B. 65 to 85 parts by mass of an aqueous phase containing at least one hydrophilic emulsifier having an HLB of at least 10, chosen from partially esterified dialiphatic polyacids, if appropriate, combined with non-esterified aliphatic polyacids; vegetable gums; and phospholipids, said hydrophilic emulsifier not being a polyethoxylated compound or a polyether compound.

2. - Emulsion according to claim 1, characterized in that part (A) is present from 18 to 31 parts by mass and part (B) from 69 to 82 parts by mass per 100 parts by mass of (A)+(B).

3. - Emulsion according to one of claims 1 and 2, characterized in that the lipophilic emulsifier(s) has / have an HLB of 6 to 7.

4. - Emulsion according to one of claims 1 to 3, characterized in that the tocopherol / tocotrienol is / are introduced in at least one of the forms α, β, γ and δ, being in particular α-tocopherol, in particular α-tocopherol.

5. - Emulsion according to one of claims 1 to 4, characterized in that the tocopherol / tocotrienol is / are present in the oily phase in an amount of 40 to 96 parts by mass and the lipophilic emulsifier(s) is / are present in an amount of 1 to 8 parts by mass.

6. - Emulsion according to one of claims 1 to 5, characterized in that the oily phase contains another oily substance chosen from vegetable oils which are not very sensitive to oxidation such as jojoba oil, sweet almond oil, argan oil, hazelnut oil, castor oil and apricot oil.

7. - Emulsion according to one of claims 1 to 6, characterized in that: - the fatty acid and carbohydrate esters included in the definition of the lipophilic emulsifier are chosen from sucrose monostearate and sucrose distearate; - the fatty acid and glycerol esters included in the definition of the lipophilic emulsifier are chosen from glycerol monostearate and glycerol distearate; - the phospholipids included in the definition of the lipophilic emulsifier are chosen from egg lecithin, soy lecithin and sunflower lecithin.

8. - Emulsion according to one of claims 1 to 7, characterized in that it also comprises, in the oily phase, at least one additional liposoluble compound chosen in particular from: - antioxidants such as lycopene and coenzyme Q10; - skin care agents such as liposoluble amino acids and their derivatives such as phenylalanine and tyrosine; liposoluble vitamins and their derivatives such as beta-carotene and retinol; and - perfuming agents such as vanilla oleoresin and essential oils, in particular in an amount of up to 40 parts by mass.

9. - Emulsion according to one of claims 1 to 8, characterized in that the hydrophilic emulsifier(s) is / are present in the aqueous phase at a concentration of 0.4 to 3% by mass of the aqueous phase.

10. - Emulsion according to one of claims 1 to 9, characterized in that: - the partially esterified polyacids, where appropriate associated with non-esterified aliphatic polyacids, falling within the definition of the hydrophilic emulsifier are chosen from emulsifiers of the carbomer series, such as the copolymer poly(acrylic acid / decyl acrylate / tri-acrylate) acontane); - the vegetable gums included in the definition of hydrophilic emulsifier are chosen from xanthan gum, guar gum; - the phospholipids included in the definition of hydrophilic emulsifier are chosen from phosphatidylserine, lyso-phosphatidylcholine and / or phosphatidylinositol; and - mono-, di- or polysaccharides partially esterified by fatty acids falling within the definition of hydrophilic emulsifier are chosen from sucrose monopalmitate and sucrose laurate.

11. - Emulsion according to one of claims 1 to 10, characterized in that that it also comprises, in the aqueous phase, at least one additional water-soluble compound chosen in particular from: - humectants such as urea; saccharides; polyols such as butylene glycol, glycerol, propylene glycol, sorbitol, xylitol and maltitol; - antioxidants such as black tea extract; cinnamon extract; astaxanthin; resveratrol and flavonoids such as hesperidin; - skin conditioning agents such as water-soluble amino acids and their derivatives such as glutamine and carnosine; water-soluble vitamins and their derivatives such as ascorbic acid, ascorbyl phosphate, nicotinamide and panthenol; α-hydroxy acids; sodium pyroglutamate; - pH regulators such as salts like sodium citrate; and - water-soluble polymers, in particular up to 40 parts by mass.

12. - Emulsion according to one of claims 1 to 11, characterized in that that it comprises a strong base chosen from sodium or potassium hydroxide or a ternary or quaternary amine, in particular present at a rate of 0.02 to 0.1 part by mass per 100 parts by mass of

13.

14.

15.

16. (A)+(B). - Emulsion according to one of claims 1 to 12, characterized in that it has an acid pH, in particular from 4.5 to 5.

5. - Emulsion according to one of claims 1 to 13, characterized in that it is in the form of a milk, a cream, a mousse or a spray. - Process for manufacturing an emulsion as defined in one of claims 1 to 14, characterized in that it comprises the following steps: - the lipophilic emulsifier(s) are dissolved in the tocopherol and / or tocotrienol, where appropriate under heating and / or under an inert atmosphere and where appropriate with the other oily substance and / or the additional liposoluble compound(s); - the hydrophilic emulsifier(s) are dispersed in water, in particular distilled or demineralized water or a hydrosol, which has been brought to the boil to release the dissolved air, where appropriate with the additional water-soluble compound(s); and - the products obtained in each of the previous steps are mixed with vigorous stirring until the desired emulsion is obtained, where appropriate with the addition of a basic aqueous solution such as a 5-10% by mass aqueous sodium hydroxide solution to the oily phase obtained and / or to the aqueous phase obtained and / or to the mixture of these two phases to neutralize the polyacids which may be present therein, where appropriate with dissolution, in the boiling water, of an electrolyte, such as a salt of a strong acid and a strong base, for example sodium or potassium chloride or sulfate, where appropriate with the addition of a non-ionic gelling agent to the mixture of the oily and aqueous phases, in particular for 0.3 to 1.5% in the aqueous phase. - Use of the emulsion as defined in one of claims 1 to 14 or as prepared in claim 15 to constitute or enter into the composition of cosmetic products.