DE4122033A1 - PRESERVATIVE-FREE WATER-IN-OIL EMULSIONS - Google Patents

Abstract

The invention concerns water-in-oil emulsions containing 10-40 % by wt. of one or more water-insoluble oils and 2-10 % by wt. of one or more water/oil-emulsifying agents. Even in the absence of preservatives, such emulsions can be conserved against microbial decay if they contain 15-30 % by wt. of one or more polyols with 2 to 12 C-atoms, 2 to 8 OH-groups and up to two aldehyde or ketone groups.

Description

The invention relates to preservative-free water-in-oil emulsions, henceforth referred to as W / O emulsions, containing one or more water insoluble oil bodies, one or more W / O emulsifiers and one or several polyols with 2 to 12 carbon atoms, 2 to 8 OH groups and up to 2 Aldehyde or ketone groups.

Cosmetic and pharmaceutical W / O emulsions must be approved by adding them protected preservatives against microbial spoilage in order to the consumer from health damage, e.g. B. by microbial To to preserve xine. Preservatives are however dermatological Findings cause many skin conditions, so need for conser free of agent-free W / O emulsions. These should go beyond that be easy to distribute, absorb well into the skin and do not stick.

The preservative-free W / O emulsions on the market are only partial solutions. For example, according to K.H. Wallhäusser (antimicrobial Conservation in theory and practice; Concept Symposium, Frankfurt 1988). with today's homogenizers, such water in oil emulsify that the incorporated water droplets are about the size of bacteria. Only then does a bacterium have a certain excess chance of life if it is in the immediate vicinity of a water droplet and from there water as well as nutrients and air dissolved in it can take. If the supply is exhausted, there is usually a drop die of the bacterium, taking it out by releasing water to the environment dries. Such systems are germ-free, but not microbiological resilient, d. H. the risk of contamination when the emulsion is removed is given.

B.J. Marshall, D.F. Ohye and D.H.B. Christian have examined how Bacteria behave when the growth medium is high in saline or glyce  contains rink concentrations. You have found that, for example Staphylococcus aureus is only killed when the water value drops below is half of 0.89 (Appl. Microbiol. 1971 (21) 363). This investigation was not based on a W / O emulsion, however, but a water-based nutrient medium for bacteria. Bacteria were also used in this example inhibitory effects only observed at very high glycerol concentrations.

G.Bäuerele et al. (Z. Hautkr. 1985 (60) 1202-1213) have subjected a cream containing 8.5% by weight glycerol to a germ load test and found that after 14 days the number of bacteria dropped from about 10 ⁴ to 0 , while the number of Penicillium species mushrooms increased by almost a power of ten from 6.0 × 10 ³ to 3.8 × 10 ⁴ . From the type of emulsifier used, however, it is clear to the person skilled in the art that this cream is a typical O / W emulsion.

The object of the present invention was to provide stable W / O emuls to make accessible, preservative-free and can also be distributed well on the skin and quickly pull.

This object was achieved according to the invention by preservative-free Water-in-oil emulsions containing - based on the entire mixture -

• A) 10-40% by weight of one or more water-insoluble oil bodies,
• B) 2-10% by weight of one or more W / O emulsifiers,
• C) 15-30% by weight of one or more polyols with 2-12 C atoms, 2-8 OH groups and up to 2 aldehyde or ketone groups,
• D) 10-55% by weight of water,
• E) 0-30% by weight of water- and / or oil-soluble auxiliary substances wherein the sum of components (A) and (B) is at least 20% by weight.

The W / O emulsions according to the invention preferably contain a polyol (C), which is selected from the group of glycerol, monosaccharides and disacchari de. As monosaccharides such. B. glucose, fructose, mannose, allo se, old rose, gulose, idose, galactose, talose, fucose, erythrose, rhamno se. As disaccharides z. B. sucrose, lactose, maltose, cello biose.  

Because of its skin-protecting properties, glycerin is particularly suitable good as polyol (C).

In a preferred embodiment, the emulsions according to the invention contain ion 20 to 30 wt .-% of the water-insoluble oil body (A). The amount of Polyols (C) preferably contained in the emulsion is 15 to 20 % By weight.

As water-insoluble oil bodies (A) can in themselves all at room temperature (20 ° C) liquid, water-insoluble, branched or linear, physio logically compatible aliphatic hydrocarbons, ethers or esters be used. It can also be solid or higher melting paraf fine, esters, waxes or fats, e.g. B. beeswax, and metal salts of Fatty acids can also be used.

From the group of aliphatic coals are well suited as oil bodies hydrogen z. B. squalane, squalene, dioctylcyclohexane, paraffinum per liquidum and Paraffinum subliquidum and isohexadecane (hydrogenated polybuty len).

Also suitable as an oil body are esters of trihydric and polyvalent Alcohols, especially vegetable triglycerides, e.g. B. olive oil, almond oil, Peanut oil, sunflower oil or the esters of pentaerythritol with z. B. Pelargonic acid or oleic acid.

Mono- and diesters of the general type are also well suited as oil bodies Formulas I, II and III

R¹-COOR² (I)

R²-OOC-R³-COOR² (II)

R¹-COO-R³-OOC-R¹ (III)

wherein R ^{1 is} an alkyl group with 8 to 22 C atoms and R ^{2 is} an alkyl group with 3 to 22 C atoms and R ^{3 is} alkylene groups with 2 to 16 C atoms and which contain at least 11 and at most 40 C atoms.

Oil bodies of the type of the mono- and diesters of the formulas (I), (II) and (III) are used as cosmetic and pharmaceutical oil components as well as and lubricant components are known. Among the mono and diesters of this Art comes the largest at liquid products at room temperature (20 ° C) Meaning too. Suitable as oil body monoesters (I) z. B. the Isopro pylester of fatty acids with 12-22 carbon atoms, such as. B. isopropyl myristate, Isopropyl palmitate, isopropyl stearate, isopropyl oleate. Other suitable mo noesters are e.g. B. n-butyl stearate, n-hexyl laurate, n-decyl oleate, isooctyl stearate, isononyl palmitate, isononyl isononanoate, 2-ethylhexyl palmitate, 2-ethylhexyl laurate, 2-hexyldecyl stearate, 2-octyldodecyl palmitate, oleyl oleate, olerucate, erucyl oleate and esters derived from technical alipha table alcohol mixtures and technical aliphatic carboxylic acids are available, e.g. B. esters of saturated and unsaturated fatty alcohols with 12-22 carbon atoms and saturated and unsaturated fatty acids with 12-22 C atoms as they are available from animal and vegetable fats are. Naturally occurring monoester or wax ester are also suitable Mixtures such as z. B. in jojoba oil or sperm oil.

Suitable dicarboxylic acid esters (II) are e.g. B. di-n-butyl adipate, di-n-butyl sebacate, di- (2-ethylhexyl) adipate, di- (2-hexyldecyl) siccinate and di-iso tridecyl acelaate. Suitable diol esters (III) are e.g. B. ethylene glycol dio leat, ethylene glycol di-isotridecanoate, propylene glycol di (2-ethylhexa noat), propylene glycol di-isostearate, propylene glycol di-pelargonate, butane diol di isostearate and neopentyl glycol di caprylate.

Branched primary alcohols such as these are also suitable as oil bodies under the name Guerbet alcohols (cf. e.g. A.J. O'Lenick Jr., R.E. Bilbo, Soap (osm. (Hem. Spec. 1987, 52) are known, e.g. 2-hexyl decanol or 2-octyldodecanol, as well as esters of Guerbet alcohols with long chain aliphatic carboxylic acids, e.g. B. with stearic acid.

The oil bodies are present in an amount in the W / O emulsions according to the invention from 10 to 40% by weight, in particular from 20 to 30% by weight, are used.

W / O emulsifiers (B) can in themselves be all nonionic surfaces tive substances are used, the one to three lipophilic, preferred  linear alkyl or acyl groups and a hydrophilic, from low molecular weight Glycol, glucose and polyol ethers included group. Here the W / O emulsifiers according to the invention should have an HLB value of 1 to 8, preferably from 1 to 6. Below the HLB value (hydrophilic lipo phil-Balance) should be understood as a value that can be calculated according to

where L is the weight fraction of the lipophilic groups, i.e. H. the fatty alkyl or fatty acyl groups in percent by weight in the nonionic surface active substance. Examples of suitable W / O emulsifiers are, for example the publication by John F.L. Chester, Drug Cosmet. 1973, p. 207 men.

From the group of W / O emulsifiers (B), fatty acid partial glycerides of saturated or unsaturated fatty acids are particularly suitable. For the purposes of the invention, this includes fatty acid partial glycerides of saturated and / or unsaturated fatty acids with 10 to 20 carbon atoms, which are in the form of technical mixtures of fatty acid mono-, di- and triglycerides and by esterification of 1 mole of glycerol with 1 to 2 moles a (C _10-20 ) fatty acid or by transesterification of 1 mole of a (C _10-20 ) fatty acid triglyceride, e.g. B. beef tallow, lard, palm oil, sunflower oil or soybean oil can be obtained with 0.5 to 2 moles of glycerin.

Two types of partial glycerides are commercially available. Partial glycerides of Type I contain 35 to 60% monoglycerides, 35 to 50% diglycerides and 1 up to 20% triglycerides. Partial glycerides of type II are by molecule Lard distillation made from those of type I and contain 90 to 95% Monoglycerides, 1 to 5% diglycerides and less than 1% triglycerides (see: a) G.Schuster and H. Adams: Zeitschrift für Lebensmittel Technologie, 1979, Volume 30 (6), pp. 256-264; b) G. Schuster (ed.) "Emulga gates for food ", Springer-Verlag, 1985).  

The fatty acid partial glycerides used according to the invention are said to be 35 to 95% monoglycerides, 1 to 35% diglycerides and 0.1 to 5% triglycerides contain. In a preferred embodiment of the present invention fatty acid partial glycerides with a mono content of 90 to 95% by weight used. Fatty acid partial glycerides based on are particularly favorable of fatty acids with chain lengths in the range from 16 to 18 carbon atoms, e.g. B. Palmitin, stearin, isostearin, isopalmitin, palmitolein, petroselin, Elaidic and oleic acid.

Polyglyces from the group of W / O emulsifiers (B) are also very suitable rinester. Polyglycerol esters within the meaning of the invention are esters of Polyglycerol with saturated or unsaturated fatty acids with 10-20 Understand C atoms. They are obtained using methods known from the literature by esterification of polyglycerol with fatty acids or by a change esterification reaction with fats. By varying the molar ratios of the Polyglycerols to the corresponding fatty acids can be used in the esterification partially or totally esterified polyglycerol esters are formed. Both at the Esterification and transesterification do not result in a uniform pro products, but mixtures consisting of mono-, di-, tri- and higher Assemble the esters of polyglycerol. The proportions of each poly glycerol esters depend on the starting compounds used, their molar ratio and their experimentation (see H. Behrens, G. Mieth; Food 1984 (28) 815). In a preferred embodiment of the In the present invention, polyglycerol esters based on di- or Triglycerin used. Based on polyglycerol esters are particularly favorable of fatty acids with chain lengths in the range of 16-18 carbon atoms, e.g. B. Pal mitin, stearin, isostearin, isopalmitin, palmitolein, petroselin, Elaidic and oleic acid. Triglycerol diisostearate is particularly suitable.

Particularly suitable W / O emulsifiers (B) are also systems Products of 5-15 mol ethylene oxide with hydrogenated castor oil.

When using high molecular oils, e.g. B. almond oil or Oleylerucat, it has proved to be advantageous, another emulsifier with also ho Hem molecular weight to use. A mixed one is particularly suitable Ester based on citric acid with pentaerytrite and fatty alcohol, e.g. B.  Dikokos-distearyl-pentaerythrityl-citrate, optionally in combination with sorbitan esters.

A fat phase consisting of oil is used to produce the W / O emulsions body (A) and emulsifier (B), melted homogeneously at 60-80 ° C. The aq phase and glycerol are combined and the heated to 60-80 ° C. Mix with the hot fat phase while stirring. The so obtained Emulsions are then cooled to 30 ° C. If desired, can by devices that work on the rotor-stator principle, e.g. B. Ultra Turrax T50 (Ika-Werke), the structure of the emulsion during the cooling process still be improved.

If desired, liquid W / O emulsions can also be produced cold by adding the amount of water and glycerin cold to the cold Fat phase, consisting of oil body (A) and emulsifier (B), and given is finally homogenized.

The W / O emulsions according to the invention can also additional contain water- and / or oil-soluble auxiliary substances (E) from the state are known in the art. The most important are:

• a) humectant, e.g. B. polyglycerols, sorbitol, 1,2-propanediol, 1,2,3- Butanetriol, polyethylene glycols, glucose, mannitol, xylitol, collagen.
• b) Oil-soluble thickeners, such as. B. calcium, magnesium and zinc soaps from C ₁₂ -C ₂₂ fatty acids.
• c) perfume oils, e.g. B. natural fragrances by distillation, Ex traction or pressing can be obtained from plants and synthetically manufactured fragrances (see e.g. H.Aebi, f.Baumgartner, H.P.Fied ler, G.Ohloff, "Cosmetics, Fragrances and Food Additives", Stuttgart 1978)
• d) antioxidants, e.g. B. tocopherols, lecithin, guaiacol, butyl cresol, 4-methyl-2,6-di-tert-butyl-phenol (BHT), 4-methoxy-2 (3) tert-butyl phenol (BHA)
• e) salts, e.g. B. Magnesium sulfate and sodium chloride
• f) oxides / pigments, e.g. B. zinc oxide
• g) pH regulators, e.g. B. citric acid. Especially when the fiction Appropriate agents are formulated so that they have a pH value close have the neutral point of the skin, the skin-protecting egg  properties of the funds are particularly emphasized. To the pH is usually in the range of 5.0 to 7.5, in particular from 5.5-7.0.
• h) dyes such as z. B. from the German Dye Commission Research Association for Cosmetics are compiled ("Coloring agent for cosmetics "Communication 3, Wiesbaden 1968).

The total amount of auxiliaries is 0-30% by weight, preferably 0-15 % By weight.

The following examples are intended to explain the subject matter of the invention in more detail tern.

Examples 1. Substances used

• 1.1 Oil body (A):
  Cetiol V: decyl oleate (Henkel / Düsseldorf)
  Emery HP2050: Anhydrous Lanolin (Henkel / Düsseldorf)
  Cetiol SB45: Shea Butter (Fa. Henkel / Düsseldorf)
  Cetiol SN: cetostearyl isononanoate (Henkel / Düsseldorf)
  Cetiol S: dioctylcyclohexane (Henkel / Düsseldorf)
  Cetiol 868: isooctyl stearate (Henkel / Düsseldorf)
  Dow Corning 344: Volatile Polydimethylcyclosiloxane (Dow Corning / Brussels)
  Lanette O: Cetostearyl alcohol [50:50] (Henkel / Düsseldorf)
  IPP: isopropyl palmitate (Henkel / Düsseldorf)
  Almond Oil: almond oil, sweet, fat (Henry-Lamotte / Bremen)
  Microcystalline Wax: micro wax (Kahl & Co./Trittau)
  Beeswax: beeswax 8100 (Kahl & Co./Trittau)
  Paraffin oil perliquidum: (Parafluid, Hamburg)
• 1.2. Emulsifiers (B):
  Dehymuls HRE 7: adduct of 7 moles of ethylene oxide with hydrogenated castor oil (Henkel / Düsseldorf)
  Monomuls 90-0 18: glyceryl monooleate, molecular distilled, monoglyceride content <90% (Grüna / Illertissen)
  Lameform TGI: triglycerol diisostearate (Grünau / Illertissen)
• 1.3. Polyols (C):
  Glycerin 99% or 86% (Henkel / Düsseldorf)
  Sucrose (Baker)
• 1.4. Excipients:
  Zinc stearate: (Bärlocher / Munich)
  Magnesium sulfate-7-hydrate: MgSO₄.7 H₂O (from Riedel de Haen)
  Zinc oxide: (from Grillo / Duisburg)
  Citric acid: (Boehringer / Ingelheim)

2. Preparation and characterization of the dispersions

To prepare the emulsions according to the invention, the fat phase was consisting of oil body (A) and emulsifier (B) - melted homogeneously at 80 ° C Zen. The aqueous phase and glycerol were combined and the to 80 ° C. warmed mixture added to the hot fat phase with stirring. Then ßend was cooled to 30 ° C.

The viscosities of the W / O emulsions thus obtained were determined at 23 ° C. measured using a RVF Brookfield viscometer; it was in the Examples 1 and 2 the plate spindle 5 at 10 revolutions per minute and in Examples 3 to 6 the cross spindle E at 4 revolutions per minute used.

3. Examples 1 to 6 (B1-B6)

According to the regulation given under point 2, those in Table 1 became compiled W / O emulsions. The emulsion of Example 2 was produced cold by the water phase and Gly cerin at 25 ° C to the fat phase, the temperature of which was also 25 ° C, was given and then homogenized. Examples 1 and 2 represent lotions, the examples 3 to 7 creams.

A germ load test was carried out on the emulsions of Examples 3 to 6. For this purpose, 100 g of an aqueous test microbial suspension containing about 108 bacteria and about 10 ⁷ fungi were added to 10 g of the cream at 20 ° C. The test germ suspension contained approximately equal proportions of the following bacteria and fungi:

Bacteria: Staphylococcus aureus, Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa, Streptococcus faecium.

Mushrooms: Candida albicans, Aspergillus niger, Penicillium rubrum, Trichoderma viride.

The evaluation was carried out according to the criteria of the United States Pharmacopeia (USP) XXI, which describes a product as adequately preserved if

• a) the number of bacteria in the reproductive bacteria not up to the 14th day is more than 0.1% of the initial bacterial count,
• b) the bacterial count of the reproductive yeasts and fungi during which he most 14 days of the examination remains the same or below the starting bacterial count decreases,
• c) the bacterial count of the test organisms during the remaining investigation lasts until the 28th day remains the same or below that in (a) and (b) determined values decreases.

It turned out that in all cases the conditions of the USP test were met. The course of the bacterial count is shown below by way of example using the emulsion of Example 7; the test germ suspension used contained 9.0 × 10 ⁸ bacteria and 7.5 × 10 ⁷ fungi:

Table 1

W / O emulsion a)

Claims (8)

1. Preservative-free water-in-oil emulsions containing - based on the entire mixture -

• A) 10-40% by weight of one or more water-insoluble oil bodies,
• B) 2-10% by weight of one or more W / O emulsifiers,
• C) 15-30% by weight of one or more polyols having 2 to 12 carbon atoms, 2 to 8 OH groups and up to 2 aldehyde or ketone groups,
• D) 10-55% by weight of water,
• E) 0-30% by weight of water- and / or oil-soluble auxiliary substances
  wherein the sum of components (A) and (B) is at least 20% by weight.

2. Preservative-free water-in-oil emulsions according to claim 1, wherein the polyol (C) is selected from the group glycerol, mono saccharide and disaccharide. 3. Preservative-free water-in-oil emulsions according to claim 1 or 2, wherein the polyol (C) is glycerin. 4. Emulsions according to one of claims 1 to 3, wherein the proportion of water-insoluble oil body (A) is 20-30% by weight. 5. Emulsions according to one of claims 1 to 4, wherein the proportion of the Polyol (C) is 15-20% by weight. 6. Emulsions according to one of claims 1 to 5, wherein the emulsifier from is selected from the group of polyglycerol esters and / or par tialglycerides. 7. Emulsions according to claim 6, wherein the polyglycerol ester is a trigly cerindiisostearate and the partial glyceride an oleic acid glyceride with egg nem is from 90 to 95 wt .-% mono.   8. Emulsions according to one of claims 1 to 5, wherein the emulsifier Addition product of 5 to 15 moles of ethylene oxide onto hydrogenated Rizi is nut oil.