WO1992001508A1

WO1992001508A1 - Oil-in-water emulsions

Info

Publication number: WO1992001508A1
Application number: PCT/EP1991/001272
Authority: WO
Inventors: Marianne Waldmann-Laue; Irina Slominski; Werner Schneider; Karlheinz Hill
Original assignee: Henkel Kommanditgesellschaft Auf Aktien; Zucker Aktiengesellschaft Uelzen-Braunschweig
Priority date: 1990-07-16
Filing date: 1991-07-08
Publication date: 1992-02-06
Also published as: DE4022540A1

Abstract

Described are oil-in-water emulsions containing, as emulsifying agent, a combination of a prior art ionic or non-ionic hydrophilic emulsifier with an HLB value of at least 10 and as co-emulsifier, a saccharic ether of general formula (I): [Z]-(R)n? in which Z is a mono- or disaccharide group or a C1?-C4? alkylglycoside of a mono- or disaccharide and R is an octadienyl, dimethyloctadienyl, octyl or dimethyloctyl group bound to an oxygen atom and the average degree of substitution n is 1 to x, where x is the number of hydroxyl groups in the mono- or disaccharide or alkylglycoside. Suitable co-emulsifiers of formula I are glucose octadienyl ether with a degree of substitution n of 1 to 3 and sucrose octadienyl ether with a degree of substitution of 2 to 6.

Description

"Oil-in-Water Emulsions"

The invention relates to oil-in-water emulsions, in particular topical cosmetic and pharmaceutical preparations in the form of O / emulsions with improved emulsion stability.

Numerous emulsifiers for converting water-insoluble oil components into the form of aqueous emulsions are known. It is known that such emulsions with water or an aqueous solution as an outer, continuous phase with relatively hydrophilic emulsifiers, e.g. can be prepared with ionic (anionic, cationic, zwitterionic or amphoteric) and with nonionic emulsifiers which have good water solubility. It is also known that, in order to improve the stability of the emulsion, additional, less hydrophilic, nonionic compounds which themselves are hardly water-soluble but carry a polar group can be used. Such so-called co-emulsifiers are e.g. Fatty alcohols with 16 to 22 carbon atoms, fatty acid partial esters of glycols or polyols with 3 to 10 carbon atoms or fatty acid alkanolamides.

The known co-emulsifiers are not always suitable for improving the emulsion stability, so that the development of a stable emulsion very often requires a great deal of work in order to find a suitable emulsifier-co-emulsifier pair.

Recently, improved processes have been developed to produce alkadienyl ethers by telomerization of conjugated dienes in the presence of an alcohol, diol or polyol in the presence of palladium catalysts.

DE-A-24 61 316 describes the preparation of di- and tri-l- (2,7-octadienyl) ethers of tri ethyl propane. If one telomerizes butadiene or isoprene in the presence of mono- or disaccharides or in the presence of alkyl (C 1 -C 4) -glucosides, mixtures of sugar ethers are obtained under suitable conditions in high yields, which consist predominantly of mono-, di- and higher substituted octadienyl or dimethyloctadienyl ethers of these polyols exist (cf. J. Prakt. Chemie, Volume 315, No. 6, 1973,

REPLACEMENT LEAF Pages 1067 to 1076). The products can be hydrogenated to the corresponding octyl and diethyl octyl ethers.

It has now been found that these sugar ethers are particularly suitable as co-emulsifiers for the preparation of oil-in-water emulsions and lead to emulsions which have superior stability even at elevated temperatures.

The invention therefore relates to emulsions of the oil-in-water type with a continuous aqueous phase and a discontinuous oil phase which, as an emulsifier, comprise a combination of a known, hydrophilic ionic emulsifier or a nonionic emulsifier with an HLB value of at least 10 a sugar ether of the general formula I

[Z] - (R) _n (I)

is contained in which Z is the residue of a mono- or disaccharide or an alkyl glycoside of a mono- or disaccharide with an alkyl group of 1 to 4 carbon atoms, R is an octadienyl, dimethyloctadienyl, octyl or dimethyloctyl group bonded to an oxygen atom and the middle group Degree of substitution n - 1 to x, where x is the number of hydroxyl groups of the mono- or disaccharide or the alkyl glycoside. The octadienyl group consists predominantly of the 1-octadiene (2,7) -yl and the 3-0ctadiene (1,7) -yl group. The diethyl octadienyl groups formed by isoprene dimerization consist of isomers not previously identified. The mean degree of substitution (n) can be increased to complete etherification of all x hydroxyl groups (n = x), but in general the sugar ethers are with a mean degree of substitution of n = 1 to 3 for monosaccharide ethers and of n = 2 to 6 best suited for disaccharide ethers.

The oil-in-water type emulsions according to the invention are understood to be both liquid O / W emulsions and O / W emulsion creams. The continuous, outer aqueous phase contains water and the components which are readily soluble in water. The dispersed oil phase consists of the oil components, the

REPLACEMENT LEAF any fat and wax components contained and all lipophilic components that are readily soluble in the oil phase.

All vegetable, animal, mineral and synthetic oils known for topical cosmetic or pharmaceutical preparations can be included as oil components. Examples include: olive oil, sunflower oil, soybean oil, corn oil, peanut oil, turnip oil, castor oil, jojoba oil, sperm oil, mink oil, paraffin oils, silicone oils, squalane, 2-0ctyl-dodecanol, decyl oleate, isopropyl stearate, isononyl stearate, 2-ethyl-hexyl palmitate, glycerol tricaprylate and other esters and hydrocarbons known as cosmetic oil components. All known products with melting points up to approx. 80 ° C are suitable as cosmetic fats and waxes. Examples include: Vaseline, hardened vegetable and animal fats (triglycerides), walrus, esters such as cetyl palmitate and natural waxes such as e.g. Beeswax, japan wax, carnauba wax, candeli ilaw wax, wool wax, mineral waxes, e.g. Montan waxes, paraffins, and polyethylene waxes.

In addition, the dispersed oil phase can also contain oil-soluble fat components with polar groups, such as have long been known as co-emulsifiers, such as e.g. Fatty alcohols with 16 to 22 carbon atoms, in particular cetyl and / or stearyl alcohol, fatty acid mono- and diglycerides, e.g. Glycerin onostearate, fatty acid monoethanol and ide and propylene glycol mono fatty acid ester, sorbitan fatty acid partial ester, methyl 1ucoside mono fatty acid ester.

The known anionic emulsifiers can be used as the hydrophilic emulsifier component, for example the soaps of fatty acids having 12 to 22 carbon atoms, the salts of phosphoric acid mono- and dialkyl (Ci2-Ci8-) esters, the salts of sulfuric acid monoesters of Ci2- C22-f ^r ettalkoholen or an¬ particular anionic surfactants, in particular those which are anhydrous and li¬-linear alkyl groups having 16 to 22 carbon atoms carry. In the same way, cationic, zwitterionic and ampholytic surfactants can also be used as hydrophilic emulsifiers for the purposes of the present invention if they have a hydrophilic, ionic group, for example a quaternary ammonium group, a betaine group or an aminocarboxylate group and in each case one

REPLACEMENT LEAF contain lipophilic, linear alkyl or alkenyl group with 12 to 22 carbon atoms.

However, nonionic emulsifiers which are obtained by adding ethylene oxide to fatty substances containing hydroxyl groups are preferably used as hydrophilic emulsifiers. Examples of such hydrophilic, nonionic emulsifiers are addition products of ethylene oxide onto, for example:

- fatty alcohols with 12 to 22 carbon atoms,

- fatty acids with 12 to 22 carbon atoms,

- Alkylphenols with 8 to 16 carbon atoms in the alkyl group

- Fatty acid (Ci2-C22) " ^moπo " ^uncl " ^c '^'' ^etnano ^ ^{a, [n'} ' ^de

- fatty acid (Ci2-C22) ^ar -P ^'t ialglyceride

- castor oil

- Fatty acid (Ci2-C22) ^_sor bitan ^partial ester

- sugar-fatty acid (Ci2-C22) -P ^a rtialester

- Alkyl (Cι-C4) glucoside fatty acid (Ci2-Ci8) partial esters.

The amount of ethylene oxide added should be so high that the hydrophilicity of these emulsifiers corresponds to an HLB value (hydrophilic-lipophilic balance) of at least 10. A nonionic emulsifier with an HLB value of 10 to 18 is preferred. For the purposes of the present invention, the HLB value should be defined as

HLB = 100

where L is the weight fraction of the lipophilic group, e.g. the fatty alkyl or fatty acyl group, in% by weight of the ethylene oxide adduct.

In a preferred embodiment, the emulsions according to the invention contain, as the emulsifier combination, a mixture of 0.5 to 9 parts by weight of a hydrophilic nonionic emulsifier with an HLB value of 10 to 18 and 1 part by weight of a sugar ether of the general formula I.

REPLACEMENT LEAF Adaptation of the emulsifier to the oil component can be advantageous if the oil phase also contains a portion of a conventional co-emulsifier, for example cetyl / stearyl alcohol or glycerol mono- / distearate. These components can be mixed with the other emulsifiers and combined into a very useful emulsifier combination, with the help of which a large number of oils can be converted into stable O / W emulsions.

A particularly preferred emulsifier combination for carrying out the present invention therefore consists of a mixture of 0.5 to 9 parts by weight of a hydrophilic nonionic emulsifier with an HLB value of 10 to 18, 1 part by weight of a sugar ether of the formula I and, if appropriate up to 2 parts by weight of a linear, saturated fatty alcohol having 14 to 22 carbon atoms (for example cetyl or stearyl alcohol) or a fatty acid partial ester of a fatty acid having 14 to 22 carbon atoms and a glycol or polyol having 3 to 10 carbon atoms. Examples of suitable fatty acid partial esters are glycerol mono / distearate, sorbitan mono- or sesquistearate, methyl glucoside sesquistearate or glucose monostearate.

The emulsifier combination according to the invention is preferably contained in an amount of 0.1 to 1 part by weight per 1 part by weight of the oil component. Particularly stable O / W emulsions and 0 / W creams are obtained when the oil phase (0) and the aqueous phase (W) are contained in a weight ratio of 0: W = 1: 9 to 4: 6 to one another.

In addition to the water-soluble surfactants, various water-soluble components can be dissolved in the aqueous phase of the emulsions according to the invention, e.g.

- Preservatives such as p-hydroxybenzoic acid ester, phenoxyethanol, chlorhexidine digluconate, formaldehyde, salts of benzoic acid, dehydroacetic acid and sorbic acid.

water-soluble thickeners, e.g. Hydroxyethyl cellulose, carboxy ethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, salts of acrylic acid and methacrylic acid poly erisät and copoly erisät, water-soluble plant matter

REPLACEMENT LEAF - water-soluble dyes

lower alcohols, glycols and polyols, e.g. 1,2-propylene glycol, 5orbitol, methyl glucoside

water-soluble cosmetic or pharmaceutical active ingredients, e.g. water-soluble plant extracts, proteins and protein derivatives, amino acids

- water-soluble buffer substances, e.g. Citrates, phosphates, borate.

The aqueous phase can also contain inorganic swelling agents and thickening agents such as swelling clays, finely divided silicas (Aerosil), talc (magnesium silicate) or magnesium aluminum silicates (eg Veegu ( ^R )).

In addition to the oil-soluble emulsifiers, antioxidants (e.g. tocopherols, butylated hydroxytoluene, etc.) and oil-soluble, pharmaceutical and cosmetic active ingredients are dissolved in the oil phase of the emulsions according to the invention.

The O / W emulsions according to the invention are expediently prepared as follows:

The oil components, fats and waxes are mixed with the emulsifier combination according to the invention and heated until a homogeneous melt is reached. The water-soluble components are dissolved in water and, preferably at a temperature of 60 to 100 ° C., combined with the organic phase with mixing. Water-soluble thickeners, water-dispersible swelling substances and water-sensitive water-soluble active substances are dissolved or dispersed separately in part of the water phase and mixed with the emulsion after cooling.

The mixing processes when emulsifying the oil and water phase or when subsequently mixing in aqueous solutions are preferably carried out using suitable mixing and emulsifying tools, e.g. of Spalth homogenizers, ultrasonic homogenizers or dynamic mixers

REPLACEMENT LEAF carried out. If the emulsion has a phase inversion in the temperature range below 100 ° C., it is advantageous to produce the emulsion above this phase inversion temperature - or to heat it briefly over this temperature range - and then to cool it down to room temperature. This measure enables particularly fine-particle, low-viscosity and still highly stable oil-in-water emulsions to be obtained.

The following examples are intended to explain the subject matter of the invention in more detail without restricting it thereto.

REPLACEMENT LEAF Examples

1. Production of O / W emulsions according to the invention

number 1

REPLACEMENT LEAF The following commercial products (trademarks) were used in the recipes:

(1) Cetiol ( ^R ) S: 1,3-dioctyl-cyclohexane (Henkel)

(2) Cetiol ( ^R ) V: decyl oleate (Henkel)

(3) Cetiol ( ^R ) SN: cetyl / stearyl isononanoate

(4) Cutina ( ^R ) KD 16: glycerol mono- / distearate / palmitate (Henkel)

(5) Glucamate ( ^R ) SSE 20: methylqlucoside sesquistearate polyglycol ether (A erchol) (20 EO)

(6) Hostacerin ( ^R ) PN 73: acrylic acid copolymer, Na salt (Hoechst)

(7) Veegum () HV: magnesium aluminum silicate (Vanderbilt)

The following sugar ethers were used:

a) Glucose octadienyl ether (n = 2.5) Preparation:

0.8685 g (2.85 mol) of 2,4-pentanedione-palladium (II) complex, 1.495 g (5.7 mmol) of triphenylphosphine, 820 g of isopropanol, 110 g of water and Given 513 g (2.85 mol) of glucose. With stirring at 600 rpm. the reactor was flushed three times with nitrogen. Then 1385 g (25.65 mol) of 1,3-butadiene were added. After heating to 65 ° C. and a reaction time of 10 hours, the mixture was cooled to room temperature (20 ° C.) and unreacted butadiene (less than 15% of the amount used) was discharged. After removal of undissolved, solid glucose (less than 5% of the amount used) by filtration, a light yellow-green solution was obtained. After removal of the solvents and the by-products which can be removed by distillation (about 11% by weight of isopropyloctadienyl ether, octatriene and octadienol), a mixture of glucose mono, di- and trioctadienyl ether with an average degree of substitution of 2.5 was obtained with the following characteristics:

REPLACEMENT LEAF Iodine number: 280 Hydroxyl number: 250 Glucose: below 1% by weight

b) glucose octadienyl ether (n = 1.5)

The preparation was carried out analogously to a) using 832 g (15.4 mol) of butadiene. The mean degree of substitution n was 1.5.

Key figures: Iodine number: 219 Hydroxyl number: 550 Glucose: approx. 10% by weight

c) sucrose octadienyl ether (n = 5.5)

The preparation was carried out analogously to a), starting from 510 g (1.488 mol) of sucrose and 1340 g (24.81 mol) of 1.3 butadiene. A mixture of sucrose octadienyl ethers with an average degree of substitution of 5.5 was obtained. The product had the following key figures:

Iodine number: 290 Hydroxyl number: 240 Sucrose: below 5% by weight

d) sucrose octyl ether (n = 4)

The preparation was carried out analogously to a), starting from 510 g (1.488 mol) of sucrose and 1000 g (18.5 mol) of 1,3-butadiene and catalytic hydrogenation of the sucrose octadienyl ether (n = 4) obtained to give sucrose octyl ether (n = 4) with the following key figures:

Iodine number: below +1

Hydroxyl number: 290

Sucrose: less than 1% by weight

REPLACEMENT LEAF 2. Testing the stability of the O / W emulsion No. 1 using the sugar ethers a, b, c, d (emulsion No. la, lb, lc, ld).

For comparison, an emulsion of the same composition was tested which contained a methyl glucoside sesquistearate (Gucate SS from AMERCHOL) instead of the sugar ether (emulsion V).

The stability of the emulsions was assessed according to the storage times given in Table I at the storage temperatures indicated on the following scale:

1 = completely homogeneous

2 = largely homogeneous

3 = slight inhomogeneity

4 = significant inhomogeneity

5 = water or oil separation

Emulsion No. la lb lc ld V

Temperature ° C 50 60 50 60 50 60 50 60 50 60

storage time

3 days 3 3 2-3 2-3 2-3 1 1 1 4-5 2-3

1 week 3 2-3 3-4 2 4 1 1 _2- - 4 1

2 weeks 3 2 2-3 1 2 1 1 2 3 1

Weeks 3 3 2 3 2 2 2 2 3 3

Weeks 4 4 2 3 2 4 2 4 3 4-5

REPLACEMENT LEAF

Claims

1. Emulsions of the oil-in-water type with a continuous aqueous phase and a discontinuous oil phase, characterized in that the emulsifier is a combination of a known hydrophilic ionic or a nonionic emulsifier with an HLB value of at least 10 with a sugar ether of the general Formula I.

[Z] - (R) _n (I)

is contained, wherein Z is the residue of a mono- or disaccharide or an alkyl glycoside of a mono- or disaccharide with an alkyl group of 1 to 4 carbon atoms, R is an octadienyl, dimethyloctadienyl, octyl or Dimethyloctyl group and the average degree of substitution n = 1 to x, where x is the number of hydroxyl groups of the mono- or disaccharide or the alkylglycoside.

2. Emulsions according to claim 1, characterized in that a mixture of 0.5 to 9 parts by weight of a hydrophilic nonionic emulsifier with an HLB value of 10 to 18 and 1 part by weight of one of the sugar ether of formula I is contained as the emulsifier combination.

3. Emulsions according to claim 1 or 2, characterized in that the emulsifier combination is contained in an amount of 0.1 to 1 part by weight per 1 part by weight of the oil component. -

4. Emulsions according to claims 1 to 3, characterized in that the oil phase (0) and the aqueous phase (W) are contained in a weight ratio of 0: W = 1: 9 to 4: 6.

REPLACEMENT LEAF

5. Emulsifier combination for the preparation of emulsions of the oil-in-water type, consisting of a mixture of 0.5 to 9 parts by weight of a hydrophilic nonionic emulsifier with an HLB value of 10 to 18, 1 part by weight of a sugar ether of the general formula I according to claim 1 and optionally up to 2 parts by weight of a linear, saturated fatty alcohol having 14 to 22 carbon atoms or a fatty acid partial ester of a fatty acid having 14 to 22 carbon atoms and a glycol or polyol having 3 to 6 carbon atoms.

REPLACEMENT LEAF