WO2021023415A1

WO2021023415A1 - Comestic nanoemulsion

Info

Publication number: WO2021023415A1
Application number: PCT/EP2020/065956
Authority: WO
Inventors: Sebastian Rosenbaum; Anke Hülshoff; Hans Breisig; Thomas Raschke; Michael WÖHRMANN
Original assignee: Beiersdorf Ag
Priority date: 2019-08-07
Filing date: 2020-06-09
Publication date: 2021-02-11
Also published as: CN114007575A; DE102019211844A1

Abstract

The present invention relates to a cosmetic nanoemulsion.

Description

Beiersdorf Aktiengesellschaft Hamburg

Cosmetic nanoemulsion

Cosmetic products generally not only serve to look beautiful and attractive, but their effect makes a decisive contribution to increased self-esteem and people's wellbeing. Accordingly, a wide variety of cosmetic products are used for the daily cleaning and care of human skin.

Skin care products are usually made up of emulsions. Emulsions are generally understood to mean heterogeneous systems which consist of two liquids which are immiscible or only partially miscible with one another, which are usually referred to as phases and in which one of the two liquids is dispersed in the other liquid in the form of very fine droplets. Externally and with the naked eye, emulsions appear homogeneous.

If the two liquids are water and oil and if oil droplets are finely distributed in water, then it is an oil-in-water emulsion (O / W emulsion, e.g. milk). The basic character of an O / W emulsion is shaped by the water. In the case of a water-in-oil emulsion (W / O emulsion, e.g. butter), the principle is reversed, the basic character being determined here by the oil.

In general, a distinction cannot only be made between water-in-oil and oil-in-water emulsions. Furthermore, a nanoemulsion represents a specific form of emulsions. A nanoemulsion has a particle size D50 of the suspended phase of up to 100 nm and forms the interfacial tension between the two phases exclusively through the introduction of energy, for example through shear forces overcome. The D50 indicates the mean particle size. Furthermore, a nanoemulsion is thermodynamically unstable. The confluence of the drops is prevented kinetically. The surface energy released when these droplets coalesce is usually not sufficient to overcome the electrostatic and steric repulsion of two droplets.

Microemulsions also have a particle size D50 of the suspended phase of up to 100 nm, but differ from nanoemulsions in that they are completely thermodynamically stable and the emulsion forms by itself. A large proportion of surfactants and / or emulsifiers (for example 20% by weight based on the total weight) is generally responsible for this. In contrast, nanoemulsions contain emulsifiers and / or surfactants in a maximum proportion of less than 10% by weight.

In addition to these two types of emulsions having a suspended phase with a particle size D50 in the range of up to 100 nm, those skilled in the art are also familiar with conventional macroemulsions which have larger particles. These can usually be found in the range from 1 pm to 500 pm (D50). Due to the size of the suspended particles, these emulsions appear visually cloudy, so that they have a white appearance like conventional cow's milk.

The cosmetic use of nanoemulsions is known to the person skilled in the art from a large number of documents. Among other things, US 2003/0087967 A1 addresses the provision of translucent nanoemulsions. However, even this document could not provide an indication of the present invention to the person skilled in the art.

A disadvantage of the prior art is the fact that it is problematic to provide viscous cosmetic nanoemulsions. If a known nanoemulsion is to be thickened, it is usually necessary to add thickening polymers. However, this is not desirable because the formula costs increase or instabilities occur which can cause coalescence.

Accordingly, a first object of the present invention was to provide a possibility of thickening a nanoemulsion.

Surprisingly, the present invention was able to eliminate the disadvantages of the prior art and to provide a nanoemulsion which does not have the disadvantages of the prior art and in which the use of thickening polymers can advantageously be dispensed with.

The invention is a cosmetic nanoemulsion comprising a) at least one fatty acid having 12 to 18 carbon atoms and b) triethanolamine.

The invention also relates to the use of a) at least one fatty acid having 12 to 18 carbon atoms and b) triethanolamine for thickening a cosmetic nanoemulsion.

If percentages by weight (% by weight) are given without reference to a certain composition or specific mixture, then this information always relates to the total weight of the cosmetic emulsion.

If ratios of components / substances / groups of substances are disclosed, these ratios relate to weight ratios of the components / substances / groups of substances mentioned.

If weight percentage ranges are given below for the constituents of the cosmetic emulsion, the disclosure of the present application also includes all individual values in steps of 0.1% by weight within these weight percentage ranges.

The formulations “according to the invention”, “advantageous according to the invention”, “advantageous within the meaning of the present invention” etc. always relate in the context of the present disclosure to the emulsion according to the invention and to the use according to the invention.

Unless otherwise stated, all tests were carried out under normal conditions. The term “normal conditions” means 20 ° C, 1013 hPa and a relative humidity of 50%.

If the term skin is used, it preferably refers to human skin.

It was surprisingly found that a nanoemulsion can be synergistically thickened by at least one fatty acid having 12 to 18 carbon atoms and triethanolamine, so that the use of further polymers as thickeners can be dispensed with.

Polymer thickeners are polymers which, when added to a nanoemulsion, increase the viscosity of the nanoemulsion.

In addition, it was surprisingly found that when the combination according to the invention is present, the transmission of light with a wavelength of 650 nm increases significantly compared to the use of the individual substances. The nanoemulsion according to the invention contains at least one fatty acid having 12 to 18 carbon atoms, the total proportion of these fatty acids advantageously from 0.5 to 5% by weight, preferably from 1 to 4% by weight and particularly preferably from 1.5 to 3.5 % By weight based on the total weight of the emulsion.

At least palmitic acid is advantageously included. If palmitic acid is contained, the proportion of palmitic acid is preferably at least 0.3% by weight, particularly preferably at least 0.8% by weight, based on the total weight of the emulsion.

It is also advantageous if at least stearic acid is included. If stearic acid is contained, the proportion of stearic acid is preferably at least 0.3% by weight, particularly preferably at least 0.8% by weight, based on the total weight of the emulsion.

Further fatty acids advantageously contained are myristic acid and arachidic acid and oleic acid.

Furthermore, it is advantageous if the proportion of triethanolamine is from 0.01 to 8% by weight, preferably from 0.05 to 5% by weight and particularly preferably from 0.1 to 2% by weight, based in each case on the total weight of the emulsion.

It is also advantageous if the weight ratio of the fatty acid having 12 to 18 carbon atoms to the weight fraction of the triethanolamine is from 1: 0.1 to 1: 0.4 and preferably from 1: 0.15 to 1: 0.3.

Furthermore, it was surprising to the person skilled in the art that the viscosity of the composition could be increased further through the specific choice of certain emulsifiers. For example, emulsifiers selected from the group of polyglyceryl esters, in contrast to anionic emulsifiers / surfactants, surprisingly showed the effect that the viscosity of the nanoemulsion could be increased further. Furthermore, it was also surprising for the person skilled in the art that, in addition to the viscosity, the transmission of light with a wavelength of 650 nm also increases significantly.

Accordingly, it is advantageous within the meaning of the present invention if at least one polyglyceryl ester is additionally included, the total proportion of polyglyceryl esters preferably from 0.2% by weight to 4% by weight and particularly preferably from 0.5% by weight to 2% by weight, based on the total weight of the emulsion. It is advantageous if the polyglyceryl esters contained are polyglyceryl-3 methylglucose distearates, polyglyceryl-10 caprylates / caprates, polyglyceryl-10 stearates and / or polyglyceryl-3 distearates. It is particularly preferred if the polyglyceryl esters present are polyglyceryl-3 methylglucose distearates and / or polyglyceryl-3 distearates.

Consequently, it is also advantageous if polyglyceryl-3 methylglucose distearate and / or polyglyceryl-3 distearate in a total proportion of 0.2% by weight to 3% by weight and in particular from 0.5% by weight to 1.5% by weight % By weight, based on the total weight of the emulsion.

Surprisingly, it has been shown that when using polyglyceryl-3 methylglucose distearate, a particularly high transmission of light with a wavelength of 650 nm is measured. Consequently, preferred embodiments of the invention are characterized in that it contains polyglyceryl-3 methylglucose distearate, the proportion of polyglyceryl-3 methylglucose distearate preferably from 0.2% by weight to 3% by weight and in particular from 0.5% by weight. -% to 1.5% by weight, based on the total weight of the emulsion.

It was also surprising that when using polyglyceryl-3 distearate a particularly large increase in the viscosity of the nanoemulsion is obtained. Consequently, further preferred embodiments of the invention are characterized in that it contains polyglyceryl-3 distearate, the proportion of polyglyceryl-3 distearate preferably from 0.2% by weight to 3% by weight and in particular from 0.5% by weight. % to 1.5% by weight, based on the total weight of the emulsion.

It is also advantageous in the context of the present invention if no anionic surfactants are contained in the emulsion, it being understood that fatty acids in the context of the present invention are not understood as anionic surfactants.

Furthermore, the nanoemulsion according to the invention advantageously comprises an oil or fat phase, the total proportion of which is advantageously from 10 to 35% by weight, preferably from 15 to 30% by weight and particularly preferably from 20 to 25% by weight, surfactants and By definition, emulsifiers do not belong to the oil phase, unless they are explicitly assigned to the oil phase in the present disclosure. The above percentages by weight for the oil or fat phase relate to the total weight of the emulsion. Emulsifiers are understood to mean all substances which are listed in the International Cosmetic Ingredient Dictionary and Handbook, Thirteenth Edition 2010, (ISBN 1-882621-47-6) under the designation “emulsifying agent”. Surfactants are understood to mean all substances which are listed in the International Cosmetic Ingredient Dictionary and Handbook, Thirteenth Edition 2010, (ISBN 1-882621-47-6) under the designation “Surfactant”.

The oil phase of the nanoemulsion according to the invention advantageously comprises cocoglycerides, the proportion of cocoglycerides preferably from 0.1 to 10% by weight, further preferably from 1 to 9.5% by weight, particularly preferably from 4 to 8.5% by weight , based on the total weight of the emulsion.

The oil phase of the nanoemulsion according to the invention also advantageously comprises Caprylic Capric T riglyceride, the proportion of Caprylic Capric T riglyceride being preferably from 1 to 8% by weight, particularly preferably from 2 to 9% by weight, based on the total weight of the emulsion amounts.

Furthermore, it is advantageous for the purposes of the present invention if the oil phase of the emulsion, at least one ester of saturated and / or unsaturated, branched and / or unbranched alkanecarboxylic acids with a chain length of 3 to 36 carbon atoms and unsaturated and / or unsaturated, branched and / or contains unbranched alcohols with a chain length of 3 to 60 carbon atoms.

These esters are preferably selected from the group consisting of isopropyl myristate, isopropyl palmitate, ethyl stearate, methyl stearate, propyl stearate, butyl stearate, ethyl palmitate, butyl palmitate, propyl stearate, isopropyl stearate, propyl palmitate, stearyl benzoate, benzyl palmitate, octanoyl benzoate, cyanonate, benzoate, octanoyl benzoate, cyanobenzoate, octanoyl benzoate, octanoyl benzoate, octanoyl benzoate, octanoyl benzoate, octanoyl benzoate, octanoyl benzoate, octanoyl benzoate, methyl stearate, methyl stearate, propyl stearate, methyl stearate, octanoyl palmitate, ethyl stearate Cetearyl isononanoate. Isopropyl palmitate, cetearyl isononanoate and / or isopropyl stearate are particularly preferred.

If isopropyl palmitate is contained, the proportion of isopropyl palmitate is preferably from 1 to 8% by weight based on the total weight of the emulsion.

If cetearyl isononanoate is present, the proportion of cetearyl isononanoate is preferably from 1 to 8% by weight based on the total weight of the emulsion. If isopropyl stearate is present, the proportion of isopropyl stearate is preferably from 1 to 8% by weight based on the total weight of the emulsion.

It is also advantageous if the oil phase contains at least one fatty alcohol having 12 to 18 carbon atoms, the proportion of fatty alcohols advantageously being from 0.5 to 3% by weight based on the total weight of the emulsion. Myristyl alcohol, cetyl alcohol, stearyl alcohol and / or cetearyl alcohol are particularly preferred as fatty alcohol.

It is also advantageous if the emulsion of the invention comprises one or more natural or synthetic oils.

Beneficial natural oils are selected from the group of sunflower oil (Helianthus Annuus Seed Oil), rapeseed oil (Canola Oil), soybean oil (Glycine Soja Oil), olive oil (Olea Europaea Fruit Oil), almond oil (Prunus amygdalus dulcis Oil), avocado oil (Persea Gratissima Oil) ), Walnut oil (Junglans Regia Seed Oil), peach kernel oil (Prunus Persica Kernel Oil), apricot kernel oil (Prunus Armeniaca Kernel Oil), sesame oil (Sesamum Indicum Seed Oil), camelia oil (Camelia Oleifera / Camelia Sasanqua), evening primrose oil (Oenothera biennis) (Macadamia Intergrifolia Seed Oil), Diestel Oil (Silybum Marianum Seed Oil), Wheat Germ Oil (Triticum Vulgare Germ Oil), Palm Kernel Oil (Elaeis guineensis Kernel Oil), Palm Oil (Elaeis guineensis Oil), Grape Seed Oil (Vitis Vinifera Seed Oil), Arganosa Oil (Arganosa Seed Oil), Peanut Oil (Arachis hypogaea Oil), Pumpkin Seed Oil (Cucurbita Pepo Seed Oil), Castor Oil (Ricinus Communis Seed Oil), Jojoba Oil, Rice Germ Oil (Oryza Sativa Bran Oil), Vegetable Oil (Olus Oil) and / or coconut oil. Jojoba oil is particularly preferred.

Furthermore, it was surprisingly found that the viscosity of the emulsion could again be increased significantly by a specific selection of the oil phase. It is correspondingly advantageous within the meaning of the present invention if the oil phase has a surface tension of more than 22 mN / m, preferably more than 25 mN / m and in particular more than 28 mN / m. In general, it is also advantageous if the surface tension of the oil phase does not exceed 35 mN / m and in particular 32 mN / m.

The values given relate to a measurement of the surface tension at 20 ° C. using a K100 tensiometer from Krüss. The measurement was carried out with a Krüss standard ring as the measuring body. The radius was 9.545 mm and the wire diameter was 0.37 mm. The parameters for the measurement were chosen as follows:

Surface detection speed: 4 mm / min Surface detection sensitivity: 0.001 g

Immersion depth: 3.00 mm

Values: 20

Data acquisition: linear

All details for the surface tension relate to the measurement method described above with the tensiometer K100.

It is also advantageous if the emulsion of the present invention is characterized in that it contains glycerol and the proportion of glycerol is advantageously from 5 to 20% by weight, preferably from 7.5 to 17.5% by weight and particularly preferred from 8 to 16% by weight, based on the total weight of the emulsion.

It is also advantageous if it contains ethanol, the proportion of ethanol preferably being from 0.5 to 2.5% by weight, based on the total weight of the emulsion.

In contrast, other embodiments of the invention are advantageously characterized in that the emulsion does not contain any ethanol.

It is also advantageous if it contains butylene glycol, the proportion of butylene glycol preferably being from 0.5 to 4% by weight, based on the total weight of the emulsion.

It is also preferred if 1,2-hexanediol, ethylhexylglycerol, benzyl alcohol, caprylyl glycol and / or phenoxyethanol are contained.

If it contains ethylhexylglycerol, the proportion of ethylhexylglycerol is advantageously from 0.1 to 0.7% by weight based on the total weight of the emulsion.

If it contains 1,2-hexanediol, the proportion of 1,2-hexanediol is advantageously from 0.3 to 4% by weight, based on the total weight of the emulsion.

If benzyl alcohol is present, the proportion of benzyl alcohol is advantageously from 0.05 to 0.5% by weight based on the total weight of the emulsion.

If caprylyl glycol is present, the proportion of caprylyl glycol is advantageously from 0.1 to 0.5% by weight based on the total weight of the emulsion. If phenoxyethanol is present, the proportion of phenoxyethanol is advantageously from 0.3 to 2% by weight based on the total weight of the emulsion.

It is also advantageous for the purposes of the present invention if the emulsion according to the invention does not contain any polymers.

Further embodiments are advantageously characterized in that the emulsion according to the invention does not contain any polymers having 50 or more repetitive identical structural units.

Furthermore, the emulsions according to the invention are advantageously characterized in that they do not contain any silicone oils.

It is also advantageous if the proportion of water is preferably from 45 to 75% by weight, in particular from 50 to 60% by weight, based on the total weight of the emulsion.

It is also advantageous if the emulsion has other active ingredients selected from the group consisting of glycyrrhetinic acid, arctic acid, folic acid, coenzyme Q10 (ubiquinone), alpha-glucosyl rutin,

Carnitine, carnosine, caffeine, natural and / or synthetic isoflavonoids, glyceryl glucose, creatine, creatinine, taurine, tocopherol, tocopherol acetate ₇ vitamin C, vitamin C phosphate, vitamin C palmitate, niacinamide, vitamin A palmitate, retinol, panthenol, glycyrrhiza inflata root extra kt, licochalcone A, 4-butylresorcinol, N - [(2,4-dihydroxyphenyl) thiazol-2-yl] isobutyramide, honociol and magnolol (also as a component of magnolia extracts), hyaluronic acid and / or silymarin (milk thistle extract).

According to the invention, the nanoemulsions are advantageously produced as follows: A pre-emulsion is formed in a rotor / stator by adding the aqueous phase at 80 ° C. to the hot oil phase. It should be noted that TEA is added to the water phase and the emulsifiers to the oil phase before the phases combine. The premix is then treated three times at 30-50 ° C. in a high-pressure homogenizer (GEA Lab Homogenizer PandaPLUS 2000) in a first stage with a pressure of 1000 bar and in a second stage with a pressure of 100 bar with cooling. The nanoemulsion according to the invention is obtained. Comparative experiments and examples

The following examples are intended to illustrate the present invention without restricting it. Unless otherwise stated, all quantities, proportions and percentages are based on the weight and the total amount or on the total weight of the preparations.

The following nanoemulsions were provided, only Examples 1, 6, 7, 8, 10 and 11 showing nanoemulsions according to the invention. The other examples 2, 3, 4, 5 and 9 are comparative examples not according to the invention.

¹ The viscosity was determined as follows:

The measured values obtained for the viscosity relate to a measurement at 25 ° C. in a 150 ml wide-neck bottle (VWR no .: 807-001) using the Rheomat R 123 from proRheo. The Rheomat R 123 from proRheo GmbH is a rotational viscometer, ie a measuring body rotates in the substance to be measured. The force is measured that is required to make the measuring body rotate in the sample at a specified speed. The viscosity is calculated from this torque, the speed of the measuring body and the geometric dimensions of the measuring system used. As a measuring body the measuring body no.1 (article no. 2000191), suitable for a viscosity range up to 10,000 [mPa-s], speed range 62.5 min- ¹ , is used.

² surface tensions were determined as described above with the tensiometer K100. The oil phase was measured on its own, i.e. separate from the other components.

The measurement of the viscosity of the nanoemulsions has shown that a surprising increase in viscosity could be achieved through the presence of the combination according to the invention of fatty acids and triethanolamine. Such an increase cannot be achieved with sodium hydroxide solution instead of triethanolamine. In addition, the examples impressively show that only very low viscosities of less than 300 mPa s are obtained when using the individual substances. Such preparations would have to be further thickened with thickening polymers.

In addition, the transmission at 650 nm was determined for Examples 1, 6 and 7 according to the invention and for Comparative Example 9 not according to the invention. The measured values obtained are listed below:

The measured transmission values were measured under normal conditions with a conventional UV / VIS spectrometer at a wavelength of 650 nm against a reference sample with distilled water. The gap width was 2 nm.

Furthermore, the comparison of Examples 10 and 11 has shown that the choice of an oil phase with a surface tension of more than 22 mN / m has made the viscosity of the nanoemulsion significantly more viscous. A thickening could thus also be achieved without the use of thickening polymers. In addition, an increase in the transmission at 650 nm was found.

Claims

1. Cosmetic nanoemulsion comprising a) at least one fatty acid having 12 to 18 carbon atoms and b) triethanolamine.

2. Nanoemulsion according to claim 1, characterized in that the total proportion of fatty acids a) from 0.5 to 5 wt .-%, preferably from 1 to 4 wt .-% and particularly preferably from 1.5 to 3.5 wt .-% %, based on the total weight of the emulsion.

3. Nanoemulsion according to one of the preceding claims, characterized in that palmitic acid is contained in a proportion of at least 0.3% by weight, particularly preferably at least 0.8% by weight, based on the total weight of the emulsion.

4. Nanoemulsion according to one of the preceding claims, characterized in that stearic acid is contained in a proportion of at least 0.3% by weight, particularly preferably at least 0.8% by weight, based on the total weight of the emulsion.

5. Nanoemulsion according to one of the preceding claims, characterized in that the proportion of triethanolamine is from 0.01 to 8% by weight, preferably from 0.05 to 5% by weight and particularly preferably from 0.1 to 2% by weight , in each case based on the total weight of the emulsion.

6. Nanoemulsion according to one of the preceding claims, characterized in that the weight ratio of the fatty acid having 12 to 18 carbon atoms to the weight proportion of the triethanolamine from 1: 0.1 to 1: 0.4 and preferably 1: 0.15 to 1: 0, 3.

7. Nanoemulsion according to one of the preceding claims, characterized in that it contains at least one emulsifier selected from the group of polyglyceryl esters and the total proportion of polyglyceryl esters is preferably from 0.2% by weight to 4% by weight and particularly preferably from 0.5 % By weight to 2% by weight, based on the total weight of the emulsion.

8. Nanoemulsion according to claim 7, characterized in that polyglyceryl-3 methylglucose distearate, polyglyceryl-10 caprylate / caprate, polyglyceryl-10 stearate, and / or polyglyceryl-3 distearate are contained as the polyglyceryl ester.

9. Nanoemulsion according to claim 7, characterized in that it contains polyglyceryl-3 methylglucose distearate, the proportion of polyglyceryl-3 methylglucose distearate preferably from 0.2% by weight to 3% by weight and in particular from 0.5% by weight. -% to 1.5% by weight, based on the total weight of the emulsion.

10. Nanoemulsion according to claim 7, characterized in that it contains polyglyceryl-3 distearate, the proportion of polyglyceryl-3 distearate preferably being from 0.2% by weight to 3% by weight and in particular from 0.5% by weight to 1.5% by weight, based on the total weight of the emulsion.

11. Nanoemulsion according to one of the preceding claims, characterized in that the nanoemulsion comprises an oil phase in a total proportion of 10 to 35 wt .-%, preferably from 12 to 30 wt .-% and particularly preferably from 15 to 25 wt .-%, whereby, by definition, surfactants and emulsifiers are not part of the oil phase.

12. Nanoemulsion according to one of the preceding claims, characterized in that the oil phase of the nanoemulsion has a surface tension of more than 22 mN / m, preferably more than 25 mN / m and in particular more than 28 mN / m.

13. Nanoemulsion according to one of the preceding claims, characterized in that the oil phase of the nanoemulsion comprises cocoglycerides, the proportion of cocoglycerides preferably from 0.1 to 10% by weight, further preferably from 1 to 9.5% by weight, particularly preferred from 4 to 8.5% by weight, based on the total weight of the emulsion.

14. Nanoemulsion according to one of the preceding claims, characterized in that the oil phase of the emulsion, at least one ester of saturated and / or unsaturated, branched and / or unbranched alkanecarboxylic acids with a chain length of 3 to 36 carbon atoms and unsaturated and / or unsaturated, branched and / or unbranched alcohols with a chain length of 3 to 60 carbon atoms.

15. Nanoemulsion according to one of the preceding claims, characterized in that the emulsion contains isopropyl palmitate, cetearyl isononanoate, ethylhexyl stearate, octyl cocoate, dicaprylyl carbonate, caprylic capric triglycerides, C12-15 alkyl benzoate and / or isopropyl stearate.

16. Nanoemulsion according to one of the preceding claims, characterized in that it contains glycerin and the proportion of glycerin is from 5 to 20% by weight, preferably from 7.5 to 17.5% by weight and particularly preferably from 8 to 16% by weight .-%, based on the total weight of the emulsion.

17. Use of a) at least one fatty acid having 12 to 18 carbon atoms and b) triethanolamine for thickening a cosmetic nanoemulsion.