DE29520749U1 - Cosmetic and pharmaceutical emulsions - Google Patents

Description

Henkel KGaA

TTP Patent Division/Dr.Fabry454/64-APG/COS
January 8, 1996

Utility model application

H2153U
"Cosmetic and pharmaceutical emulsions"

Area of invention

The invention relates to cosmetic and pharmaceutical emulsions with improved stability, containing alkyl oligoglucosides, fatty alcohols and monoglyceride (ether) sulfates in selected mixing ratios.

State of the art

The use of mixtures of alkyl oligoglucosides, fatty alcohols and optionally polyglucose for the production of emulsions is known from European patent specification EP-Bl 0 553 241 (SEPPIC). According to the teaching of international patent application WO 92/07543 (Henkel), alkyl oligoglucosides can also be used together with fatty alcohols and partial glycerides as cosmetic emulsifiers.

In addition to oils, surfactants are also often used to produce cosmetic and pharmaceutical products such as creams, lotions or ointments. It turns out that the resulting emulsions are stable at room temperature and have a sufficiently high viscosity, but that they gradually break down during longer storage periods, especially when exposed to high temperatures. Thin, liquid products are produced and in a number of cases separation can also occur.

The object of the invention was therefore to provide emulsions for cosmetic or pharmaceutical applications based on alkyl oligoglucoside/fatty alcohol mixtures for

To provide products that are free from the disadvantages of the state of the art described above, i.e. that are stable in storage over long periods even when exposed to high temperatures.

Description of the invention

The invention relates to cosmetic and/or pharmaceutical preparations, containing - based on the emulsifier content -

(a) 10 to 50 wt.% C ₁₆ -C ₂₂ alkyl oligoglucosides,

(b) 50 to 90 wt.% Ci ₆ -C ₂₂ fatty alcohols and

(c) 0.1 to 10 wt.% monoglyceride (ether) sulfates

provided that the quantities add up to 100% by weight.

Surprisingly, it was found that a mixture of alkyl oligoglucosides and fatty alcohols within defined application ratios together with selected surfactants of the monoglyceride or monoglyceride ether sulfate type produce emulsions that are storage-stable, i.e. whose viscosity does not change even after prolonged storage at elevated temperatures. The invention includes the knowledge that the selection of the surfactant component is crucial for the stability of the emulsions, since with other surfactants only emulsions of significantly lower stability are obtained.

Alkyl oligoglucosides

Alkyl oligoglucosides are known nonionic surfactants that follow the formula (I),

rO-[G] _p (I)

in which R is an alkyl radical having 16 to 22 carbon atoms, G is a glucose radical and ρ is a number from 1 to 10. They can be obtained by the relevant methods of preparative organic chemistry. As representatives of the extensive literature, reference is made here to the documents EP-Al-O 301 298 and WO 90/03977 . The index number ρ in the general formula (I) indicates the degree of oligomerization (DP), ie the distribution of mono-

H2153 Ø , . 3× . ....

and oligoglycosides and represents a number between 1 and 10. While ρ in a given compound must always be an integer and can assume the values ρ = 1 to 6, the value ρ for a specific alkyl oligoglucoside is an analytically determined calculated value that is usually a fractional number. Alkyl oligoglucosides with an average degree of oligomerization ρ of 1.1 to 3.0 are preferably used. From an application point of view, alkyl oligoglucosides are preferred whose degree of oligomerization is less than 1.7 and in particular between 1.2 and 1.4. The alkyl radical R ¹ can be derived from primary alcohols with 16 to 22 carbon atoms. Typical examples are alkyl oligoglucosides based on cetyl alcohol, stearyl alcohol, isostearyl alcohol and/or behenyl alcohol and technical mixtures thereof. Alkyl oligoglucosides derived from fatty alcohols with 16 to 18 carbon atoms, such as cetearyl alcohol in particular, are preferably used.

Felt alcohols

Fatty alcohols are primary aliphatic alcohols of formula (II),

R ² OH (II)

in which R is an aliphatic, linear or branched alkyl radical with 16 to 22 carbon atoms. Typical examples are cetyl alcohol, stearyl alcohol, isostearyl alcohol and behenyl alcohol as well as technical mixtures thereof, which are obtained, for example, in the high-pressure hydrogenation of technical methyl esters based on fats and oils. Technical mixtures with 16 to 18 carbon atoms, such as cetearyl alcohol in particular, are preferred.

For the purposes of the invention, it is particularly advantageous to use mixtures of alkyl oligoglucosides and fatty alcohols which have identical alkyl radicals, for example mixtures of cetearyl oligoglucosides and cetearyl alcohol.

H2153U

Monoglyceride(ether)sulfate

·♦· ♦··

♦ m ··

Monoglyceride sulfates and monoglyceride ether sulfates are known anionic surfactants that can be obtained using the relevant methods of preparative organic chemistry. They are usually produced from triglycerides, which are optionally transesterified to monoglycerides after ethoxylation and then sulfated and neutralized. It is also possible to react the partial glycerides with suitable sulfating agents, preferably gaseous sulfur trioxide or chlorosulfonic acid [cf. WO 92/09 569, WO 92/09 570 (Henkel)]. If desired, the neutralized substances can be subjected to ultrafiltration in order to reduce the electrolyte content to a desired level [DE-Al 42 04 700 (Henkel)]. Overviews of the chemistry of monoglyceride sulfates are provided, for example, by AKBiswas et al. in J. Am. Oil. Chem.Soc. 27.» 171 (1960) and FUAhmed J. Am. Oil. Chem. Soc. 61, 8 (1990) .

The monoglyceride (ether) sulfates to be used in the invention follow the formula (III)

CH ₂ O(CH ₂ CH ₂ O) _x -COR ³ CH-O(CH ₂ CH ₂ O) _y H CH ₂ O(CH ₂ CH ₂ O) ₂ -SO ₃ X

in which R ³ CO represents a linear or branched acyl radical having 6 to 22 carbon atoms, x, y and ζ in total represent 0 or numbers from 1 to 30, preferably 2 to 10, and X represents an alkali or alkaline earth metal.

Typical examples of monoglyceride (ether) sulfates suitable for the purposes of the invention are the reaction products of lauric acid monoglyceride, coconut fatty acid monoglyceride, palmitic acid monoglyceride, stearic acid monoglyceride, oleic acid monoglyceride and tallow fatty acid monoglyceride and their ethylene oxide adducts with sulfur trioxide or chlorosulfonic acid in the form of their sodium salts. Monoglyceride sulfates of the formula (III) are preferably used, in which R ³ CO represents a linear acyl radical having 8 to 18 carbon atoms.

Commercial applicability

The emulsions according to the invention are characterized by a high storage stability even under temperature stress. In a preferred embodiment of the invention, the emulsions contain - based on the emulsifier content - 20 to 40% by weight of alkyl oligoglucosides, 60 to 80% by weight of fatty alcohols and 5 to 8% by weight of monoglyceride sulfates. The non-aqueous portion of the emulsions, which is largely made up of the emulsifier and oil content and generally corresponds to the solids content, is usually 5 to 95 and preferably 15 to 75% by weight. Conversely, this means that the emulsions can contain 5 to 95 and preferably 25 to 85% by weight of water, depending on whether lotions with a comparatively low viscosity or creams and ointments with a high viscosity are to be produced.

Oil body

Examples of suitable oil components are Guerbet alcohols based on fatty alcohols having 6 to 18, preferably 8 to 10 carbon atoms, esters of linear C ₆ -C ₂₀ fatty acids with linear C ₆ -C ₂ o fatty alcohols, esters of branched C 8 -C 12 carboxylic acids with linear C ₆ -C ₂ o fatty alcohols, esters of linear C ₆ -C ₁₂ fatty acids with branched alcohols, in particular 2-ethylhexanol, esters of linear and/or branched fatty acids with polyhydric alcohols (such as dimerdiol or trimerdiol) and/or Guerbet alcohols, triglycerides based on C ₆ -C ₁₀ fatty acids, vegetable oils, branched primary alcohols, substituted cyclohexanes, Guerbet carbonates, dialkyl ethers and/or aliphatic or naphthenic hydrocarbons. The proportion of oil bodies in the non-aqueous portion of the emulsions can be 5 to 99 and preferably 10 to 75% by weight

Aids and additives

The emulsions can be used as skin care products, such as day creams, night creams, care creams, nourishing creams, body lotions, ointments and the like and can contain oil components, emulsifiers, superfatting agents, fats, waxes, stabilizers, biogenic active ingredients, glycerin, preservatives, colorants and fragrances as additional auxiliary and additive substances.

Suitable non-ionic OAV co-emulsifiers are (a1) addition products of 2 to 30 moles of ethylene oxide and/or 0 to 5 moles of propylene oxide with linear fatty alcohols having 8 to 22 carbon atoms, with fatty acids having 12 to 22 carbon atoms and with alkylphenols having 8 to 15 carbon atoms in the alkyl group; (a2) C ₁₂ /g fatty acid mono- and diesters of addition products of 1 to 30 moles of ethylene oxide with glycerol; (a3) glycerol mono- and diesters and sorbitan mono- and diesters of saturated and unsaturated fatty acids having 6 to 22 carbon atoms and their ethylene oxide addition products; (a4) addition products of 15 to 60 moles of ethylene oxide with castor oil and/or hardened castor oil; (a5) polyol and in particular polyglycerol esters such as polyglycerol polyricinoleate or polyglycerol poly-12-hydroxystearate. Mixtures of compounds from several of these substance classes are also suitable. The addition products of ethylene oxide and/or propylene oxide with fatty alcohols, fatty acids, alkylphenols, glycerol mono- and diesters and sorbitan mono- and diesters of fatty acids or with castor oil are known, commercially available products. These are homolog mixtures whose average degree of alkoxylation corresponds to the ratio of the amounts of ethylene oxide and/or propylene oxide and substrate with which the addition reaction is carried out. C ₁₂ /ig fatty acid mono- and diesters of addition products of ethylene oxide with glycerin are known from DE-PS 20 24 051 as refatting agents for cosmetic preparations.

The following can be considered as W/O co-emulsifiers : (b1) addition products of 2 to 15 moles of ethylene oxide with castor oil and/or hardened castor oil; (b2) partial esters based on linear, branched, unsaturated or saturated C^1 fatty acids, ricinoleic acid and 12-hydroxystearic acid and glycerin, polyglycerin, pentaerythritol, dipentaerythritol, sugar alcohols (e.g. sorbitol) and polyglucosides (e.g. cellulose); (b3) trialkyl phosphates; (b4) wool wax alcohols; (b5) polysiloxane-polyalkyl-polyether copolymers or corresponding derivatives; (b6) mixed esters of pentaerythritol, fatty acids, citric acid and fatty alcohol according to DE-PS 11 65 574 and (b7) polyalkylene glycols.

The proportion of emulsifiers and co-emulsifiers in the non-aqueous portion of the emulsions can be 0.1 to 10 and preferably 1 to 7 wt.%.

Substances such as polyethoxylated lanolin derivatives, lecithin derivatives, polyol fatty acid esters, monoglycerides and fatty acid alkanolamides can be used as superfatting agents, the latter also serving as foam stabilizers. Typical

Examples of fats are glycerides, and waxes include beeswax, paraffin wax or micro waxes, possibly in combination with hydrophilic waxes, e.g. cetylstearyl alcohol. Metal salts of fatty acids such as magnesium, aluminum and/or zinc stearate can be used as stabilizers . Biogenic active ingredients include plant extracts and vitamin complexes. Suitable preservatives include phenoxyethanol, formaldehyde solution, parabens, pentanediol or sorbic acid. Pearlescent agents include glycol distearic acid esters such as ethylene glycol distearate and fatty acid monoglycol esters. Substances suitable and approved for cosmetic purposes can be used as colorants , such as those listed in the publication "Cosmetic Colorants" by the Dye Commission of the German Research Foundation, Verlag Chemie, Weinheim, 1984, pp. 81-106 . These dyes are usually used in concentrations of 0.001 to 0.1 wt.%, based on the total mixture.

Typical emulsions have compositions as shown in Table 1 (provided that the figures add up to 100% by weight).

Table 1

Typical composition of lotions and creams

component Lotion [% by weight] 1-2 Cream [% by weight] 1-3 Alkylpolyglucoside 2-3 2-6 Fatty alcohols 0.1-0.5 0.1-0.5 Monoglyceride sulfates 25-50 25-50 Oil body 1-5 1-5 Auxiliaries and additives 50-70 25 to 50 Water

The total proportion of auxiliary and additive substances can be 1 to 10, preferably 2 to 5 wt.% based on the agent. The agent can be produced in a manner known per se, i.e. for example by hot, hot-hot/cold or PIT emulsification. This is a purely mechanical process; a chemical reaction does not take place.

Examples

Emulsions were prepared containing 35% by weight of oil body (Cl to C3), 5% by weight of emulsifier/surfactant mixture and up to 100% by weight of water. The emulsions were prepared using the PIT method, i.e. above the phase inversion temperature. Formulations R1 and R2 contain the combination of components Al to A3 and are in accordance with the invention. Formulations R3 to R8 contain the emulsifier combination Al and A2, but a surfactant not in accordance with the invention (B1 to B6) and are used for comparison. The viscosity of the samples was determined using the Brookfield method in an RVF viscometer (20 rpm, spindle 1) immediately and after storage for 7 days at 20 or ^{40 °} C. The results are summarized in Table 2.

Substances used (CTFA nomenclature where possible)

A1) Hexadecyl Polyglucose

A2) Hexadecyl Alcohol

A3) Coconut monoglyceride sulfate sodium salt

B1) Dodecylbenzenesulfonate sodium salt

B2) a-Hexadecenesulfonate sodium salt

B3) a-Sulfotalfatty acid methyl ester sodium salt

B4) secondary hexadecanesulfonate sulfonate sodium salt

B5) Mono/Dilauryl Phosphate Mono/Di-Sodium Salt

B6) Ceteareth-10

C1) Dicapryl Ether

C2) Decyl Oleate

C3) Almond oil

Table 2

Viscosity and storage stability (quantities as % by weight)

·

Components Rl 1.9 R2 2.25 R3 1.9 m:^ ; R5 12 1.9 R6 1.9 R7 1.9 R8 1.9 Al 2.85 2.25 2.85 1.9 8th 2.85 2.85 2.85 2.85 A2 0.25 0.5 - 2.85 2 - - - - A3 - - 0.5 - - - - - Bl - - - - - - - - B2 - - - 0.5 0.5 - - - B3 - - - - - 0.5 - - B4 - - - - - - 0.5 - B5 - - - - - - - 0.5 B6 15 15 15 - 15 15 15 15 Cl 10 10 10 15 10 10 10 10 C2 5 5 5 10 5 5 5 5 C3 5 Water to 100 viscosity
[fmPas] .500 ,000 10,000 ,000 ,000 ,000 ,000 - immediately 10 .500 11 ,000 7,800 10,000 ,000 11 .500 10 ,000 10 ,000 -after 7d,20°C 10 .500 11 ,000 4,500 6,800 .500 8th ,000 9 .500 9 ,000 -after 7d,40°C 10 11 3,000 2 1 1

It can be seen that storage-stable emulsions can only be obtained using the three-combination according to the invention, i.e. using the selected anionic surfactants.

Claims (7)

Protection claims 1. Cosmetic and/or pharmaceutical emulsions containing - based on the emulsifier content - (a) 10 to 50 wt.% C ₁₆ -C ₂₂ alkyl oligoglucosides, (b) 50 to 90 wt.% C ₁₆ -C22 fatty alcohols and (c) 0.1 to 10 wt.% monoglyceride (ether) sulfates, provided that the quantities add up to 100% by weight. 2. Emulsions according to claim 1, characterized in that they contain alkyl oligoglucosides of the formula (I), in which R ¹ is a linear, saturated alkyl radical having 16 to 22 carbon atoms, G is a glucose radical and ρ is a number in the range from 1 to 10. 3. Emulsions according to claims 1 and 2, characterized in that they contain fatty alcohols of formula (II), R ² OH (II) in which R ² stands for an aliphatic, linear or branched alkyl radical having 16 to 22 carbon atoms. 4. Emulsions according to claims 1 to 3, characterized in that they contain monoglyceride (ether) sulfates of the formula (III), CH ₂ O(CH ₂ CH ₂ O) _x -COR ³ CH-O(CH ₂ CH ₂ O) _y H (III) CH ₂ O(CH ₂ CH ₂ O) ₁ -SO ₃ X H2153U , , 11 in which R ³ CO stands for a linear or branched acyl radical having 6 to 22 carbon atoms, x, y and ζ in total stand for O or for numbers from 1 to 30 and X stands for an alkali or alkaline earth metal. 5. Emulsions according to claims 1 to 4, characterized in that they contain oil bodies which are selected from the group formed by Guerbet alcohols based on fatty alcohols having 6 to 18 carbon atoms, esters of linear C ₆ -C ₂₀ fatty acids with linear C 12 -C 20 fatty alcohols, esters of branched C ₆ -C ₁₃ carboxylic acids with linear C ₆ -C ₂₀ fatty alcohols, esters of linear C ₆ -C ₁₆ fatty acids with branched alcohols, esters of linear and/or branched fatty acids with polyhydric alcohols and/or Guerbet alcohols, triglycerides based on C ₆ -C ₁₈ fatty acids, vegetable oils, branched primary alcohols, substituted cyclohexanes, Guerbet carbonates, dialkyl ethers and/or aliphatic or naphthenic hydrocarbons. 6. Emulsions according to claims 1 to 5, characterized in that they have a non-aqueous content of 5 to 95 wt.%. 7. Emulsions according to claims 1 to 6, characterized in that they have an emulsifier content of 0.1 to 10 wt.% - based on the non-aqueous portion.