GB2226256A - Hyrocarbon/polyhydric alcohol emulsions - Google Patents

Description

h I- 1 AN EMULSION THIS INVENTION RELATES to an emulsion for a base which

may be utilized on its own or as a base to which additional ingredients may be added.

According to a f irst aspect of the invention there is provided a stable emulsion which is substantially anhydrous and comprises first constituent which is a hydrocarbon wax, gel or oil; second constituent which is a polyhydric alcohol; and third constituent which is an emulsifying agent.

According to a second aspect of the invention there is provided a stable emulsion which comprises first constituent which is a hydrocarbon wax, gel or oil; second constituent which is a polyhydric alcohol; third constituent which is an emulsifying agent; and 2 water in an amount which constitutes not more than 60%, and preferably not more than 40% by mass of the emulsion.

Any suitable hydrocarbon wax, gel or oil may be used. A particularly suitable material is petroleum jelly. A preferred petroleum jelly is white petroleum jelly B.P. It is a mixture of purified, bleached, largely saturated hydrocarbons. In its normal semi-solid state it is a two-phase colloidal system or gel comprising high molecular weight hydrocarbons dispersed in microcrystalline or amorphous waxes. Alternatively, petrolatums (eg. yellow petrolatum) can be used. Details of these materials are set out in the examples which follow.

The polyhydric alcohol conveniently may be an aliphatic polyhydric alcohol, eg. glycerine or sorbitol or propylene glycol.

The emulsifier can be any suitable emulsifier. It may, for example, comprise at least one sulphated higher alcohol having a carbon chain length of from Clo to C20 Conveniently it is an anionic self-emulsifying wax which may be a partially sulphated mixture of cetyl and stearyl alcohols. A particularly suitable emulsifier is emulsifying wax BP which is obtainable, for example, as LANETTE SX, CRODEX A, CYCLOCHEM or CYCLONETTE WAX. "LANETTE". "CRODEX", 11CYCLOCHEM" and 11CYCLONETTE" are believed to be registered trade marks of Ronsheim & Moore (UK), Croda (UK), Witco (UK) and Witco (UK) respectively.

3 A suitable anhydrous emulsion can be prepared using about 10 to 40% by mass of the gel, wax or oil, about 60 to 90% by mass of the polyhydric alcohol and an amount not exceeding 12% of the emulsifier.

A typical anhydrous emulsion according to the invention may comprise 20 to 30% (preferably about 25%) by mass of petroleum jelly, 70 to 80% (preferably about 72%) by mass of glycerine and 3.5 to 10.0% (preferably about 4%) by mass of emulsifying wax BP.

The emulsion provided by the invention can be either an alcohol-in-oil emulsion wherein the polyhydric alcohol is the disperse phase and the hydrocarbon wax, gel or oil is the continuous phase, or an oil-in-alcohol emulsion wherein 'L-he hydrocarbon wax, gel or oil is the disperse phase and the polyhydric alcohol is the continuous phase. Whether an alcoholinoil or an oil-in-alcohol emulsion is formed appears to depend solely upon the relative proportions of the two constituents. Without being bound by theory, it appears that the droplets of the disperse phase are coated with the emulsifying agent and these coated droplets are dispersed in the continuous phase to provide a stable product.

By varying the proportion of the wax, gel or oil, the vi.cosity of the emulsion can be adjusted. If the proportion is increased, the viscosity is increased. If the proportion is decreased, the viscosity is decreased.

1 4 The emulsion conveniently can be prepared by having a mixing tank which is supplied with the constituents from their own separate tanks. The polyhydric constituent (such as glycerine) conveniently may be heated to a temperature of about 55 to 900C and the other main constituent, such as petroleum jelly, can conveniently be heated to about 55 to 900C. The emulsifier conveniently can then be mixed with the -petroleum jelly and thereafter this mixture incorporated into a final base mix with the glycerine. Mixing may be effected down a spiral mixer.

The invention extends to a method of preparing a stable emulsion. which includes heating a hydrocarbon wax, gel or oil to a temperature of from 550C to 90'C; adding a suitable emulsifying agent to the hot hydrocarbon wax, gel or oil; heating a polyhydric alcohol to a temperature of fron, 55C to 90OC; and mixing the hot polyhydric alcohol with the hot mixture of hydrocarbon wax, gel or oil and emulsifying agent to form a homogeneous mixture.

The preferred mixing temperature for each of the hydrocarbon wax, gel or oil and polyhdric alcohol is 75 to 800C. Preferably, these constituents are at substantially the same temperature when they are mixed together.

The heating together of the constituents and mixing of them enables a homogeneous mixture of the hydrocarbon wax and the polyhydric alcohol to be obtained without having water present. After the mixing of the constituents within the temperature range indicated, the mixture is cooled to give the homogeneous product. The product at room temperature usually is a soft gel.

If desired, other materials can be added, for example perfumes, medicaments or other active pharmaceutical ingredients, active cosmetic ingredients or the like. Particular examples are antimycotic agents such as Amphotericin (eg in an amount constituting about 3% by mass of the emulsion), Clotrimazole (eg in an amount constituting about 1% by mass of the emulsion), Econazole (eg about 1%), and Miconazole (eg about 2%); anti-inflammatory agents such as betamethasone-17-valerate (eg about 0,1%), hydrocortisone (eg about 1%), Prednisolone (eg about 0,5%), Clobetasone butyrate (eg about 0.05%), and Indomethacin (eg about 0.1%); antiseptic agents such as Cetrimide (eg about 0.5%), and Cetylpyridium chloride (eg about 0.5%); and 6 sunscreen agents/ultra-violet absorbers such as Sulisobenzone (eg about 8%), ethylmexyl p-methoxyannamate (eg about 6%), and benzyl salicylate (eg about 2 to 7%).

Either water soluble, or oil soluble additives can be added to the emulsion according to the invention and mixed in at room temperature to provide a homogeneous stable product.

The emulsion provided by the invention may be utilized as a cosmetic base to be applied to the skin. It may also be utilized for the administration of other cosmetic materials or for the administration of pharmaceutically active materials topically to a patient. Furthermore, it can be used as a base for hair straighteners. Where the emulsion is intended for use with medicaments, the preferred polyhydric alcohol constituent may be propylene glycol propan-1,2-diol, ie C3H802).

Thus the invention extends further to the use of an emulsion according to the invention for preparing a substance or composition for application to the human skin or hair, and yet further to a substance or composition for cosmetic or therapeutic application to the human skin or hair when prepared from an emulsion according to the invention.

1 7 Furthermore and as mentioned above, if it is to be used as a sunburn cream, it may contain other materials to screen the effectiveness of the sun.

The following tables a) and b) give details of the content of white petroleum jelly and yellow petrolatum respectively.

8 WHITE PETROLATUMS WAXREX 521 (STANDARD WHITE) WHITE PETROLATUM BP/USP 76613 PROPERTIES METHOD SPECIFICATION! TYPICAL

Colour, Lovibond IP 17 1.5 Y/0.3 R max 0.5 Y/0,1 R (21' cell) hot Drop Melting Pt. C IP 31 38 - 56 50 Penetration at 25cC, ASTM 150 - 180 160 dnm D937 Viscosity, MM2/sec at ASTM no set specifi- 11.9 1006C D445 cation Light Absorption BP 0.50 max 0.06 (0.05t soln at 290 nm) Foreign organic Matter BP No acrid odour Pass evolved Sulphated Ash BP 0.1% max Pass Acidity/Alkalinity BP/UP- neutral to Pass litmus under test conditions Specific Gravity at USP 0.815-0.880 0.877 60/60-F organic Acids USP Not more than Pass 400 pLl of 0.100 N NaOH Penetration, CIMM ASTM 100 - 300 160 Fixed oils, Fats and USP No oily or solid Pass Resins matter separates after test Residue on Ignition USP 0.1% max Pass 9 (b) PETROLATUMS (YELLOW PETROLATUMS) WAXREX 562 PETROLATUM USP YELLOW (YELLOW PETROLATUM), (YELLOW SC) WAXREX 541 YELLOW (STANDARD YELLOW) PROPERTIES METHOD 76796 76814 lColour, Lovibond IIP 17::35y / 3R 15Y / 1.5R 1(2" cell) Max. (1.5" Cell) Melting Point, 0C iASTM 53 - 58 158 - 65 :D127 I Penetration at 25'C ASTM 210 - 245;i160 - 180 D937 2 Viscosity, mm /sec at ASTM 10.5 - 16.5 6.5 8.25 1 1 98.90C D445 i Light Absorption BP absorbence at absorbence at 29 nm less than.9 nm less thanj -0.75 D. 75 1 Foreign Organic Matter'BP/USP po acrid odour no acrid odour ' evolved evolved Sulphated Ash BP:0.1 % max. b.1 % max, -0.880 Specific Gravity at USP 0 815 15.6/15,60C Orgailic Acids USP ot more than not more than 1400pl of 0.10ON 4001A1 of 0.10ON j PaOH a0H Penetration ASTM 50-180 dmm L50-180 dmm Fixed Oils, Fats PSP no oily or solid no oily or solid and Resins matter separates 1matter separate ifter test c;after test 11WAXREX11 is a trade mark of TEXACO which is a German Company.

1176796"#, 117681411 and 117661311 are TEXACO's identification numbers for the petrolatum's specified in Tables (a) and (b).

11LOVIBOND11 is a trade name for an instrument supplied by British Drug Houses and used for the purpose of comparing and matching colours.

11ASTM D93711 is an abbreviation for American Society of Testing Materials, test D937.

IIIP1711 is an abbreviation for "International Pharmacopoeia, test no. 17 IIIP3111 is an abbreviation for "International Pharmacopoeia, test no. 3111 "BP" is an abbreviation for "British Pharmacopoeia".

11USP11 is an abbreviation for "United States Pharmacopoeia".

11Y11 is an abbreviation for "yellow", and "R" is an abbreviation for "red". Thus 111.5Y/0.3 R naxII should be read as 111.5 yellow/0.3 red maximum".

11 The invention is now described by way of the following non-limiting example in which the hydrocarbon wax, gel or oil (ie the first constituent) is white petroleum jelly, the polyhydric alcohol (ie the second constituent) is glycerine, and the emulsifying agent (ie the third constituent)is LANETTE SX.

Glycerine is a syrupy liquid which absorbs moisture from the air and is known chemically as propan-1,2,3-triol and has the formula C 3 H 8 0 3 LANETTE SX comprises a colloid disperse mixture composed of 90 parts "LANETTE" 0 to 10 parts of sodium alkyl sulphate. Its CTFA designation is cetearyl alcohol and sodium lauryl sulphate. it is a yellow to white granulated mass containing approximately 99% of fats, 0.235 to 0.279 mvalg, a maximum of 1.4% of inorganic salts, a maximum of 1.0% water, a pH value (as a 1% suspension) of 6.5 to 8 and a solidification temperature of 50 to 540C.

ICTFA" is an abbreviation for Cosmetic Toiletry and Fragrances Association.

The mixing of the constituents can be carried out using the apparatus illustrated in the accompanying drawings in which FIGURE 1 is a schematic representation of an apparatus for preparing an emulsion according to the invention; and FIGURE 2 is a three dimensional view of a component of the apparatus.

12 In Figure 1, reference numeral 10 generally indicates an -apparatus for preparing an emulsion according to the invention.

For brevity and ease of description, the apparatus is described in its in use orientation as shown as Figure 1, and words such as "horizontal". "top", "above", etc. which generally indicate relative position or direction, should not be construed as limiting.

The apparatus 10 includes two supply tanks 12 and 14, each having capacity for 285 kg glycerine and a supply tank 16 which can hold 196 kg petroleum jelly. These tanks may be any heating vessel. Preferably they are electric pots (eg Vulcan pots) which facilitate fine control of temperatures.

The tanks 12, 14, 16 communicate with a mixing tank 18 which open at the top, via connecting pipes 20 and a manifold 22. Tank 18 has a maximum capacity of 1000 kg. The connecting pipes 20 are fitted with valves 24 to permit manual adjustment of the rate of discharge of the contents of the tanks 12, 14, 16.

The manifold 22 includes a spiral mixer (not shown) with five 3600 turns for mixing the contents of the supply tanks 12, 14, 16 before feeding into the mixing tank 18. The spiral mixer has been specially designed to give an appropriate primary 13 mix of the hot liquid before it enters the mixing tank 18. The diameter of the spiral mixer should be large enough to accommodate the flow of liquid from the tanks 12, 14 and 16 when the valves 24 are fully opened. The lower end portion of the spiral mixer is disposed at an angle of 300 to the horizontal above the open mixing tank 18.

An electric motor driven pump 26 is provided for recirculating the contents of the mixing tank 18 by pumping the contents out of an opening 28 in the bottom wall of the tank 18 and to feed back into the tank 18 adjacent its top opening, via a pipe 30 which has a diameter in the range of from 12 to 40 mm.

The preferred size of the motor (not shown) is a 1.1 kw, 50 Hz, 1390 rpm motor to which is fitted a gearing unit for reducing the revolutions to 226 rpm. The motor drives a circular-section cylinder 32 of hard nitrile rubber which is rotatable about its longitudinal axis and in a direction indicated by arrow 34. The cylinder 32 is a snug fit within a tubular casing or stator (not shown). The outer surface 36 of the cylinder 32 defines a spiral groove 38 which extends between the opposed ends of the cylinder 32. In use, the cylinder 32 is driven at approximately 226 rpm. The contents of the mixing tank 18 enter the pump 26 and are urged along the groove 36 in the direction indicated by arrow 40, before entering the pipe 30 and returning to the mixing tank 18.

The following non-limiting example illustrates the invention.

Each of the tanks 12and 16 were charged with 280 kg of glycerine and the tank 14 was charged with 196 kg petroleum jelly. The glycerine and petroleum jelly in these tanks were heated slowly up to a temperature of between 73 and 75C. 38 kg of IANETTE SX were then added to the petroleum jelly in the tank 14 and the resulting mixture was agitated until the IANETTE SX dissolved in the petroleum jelly.

When the contents of the tanks 12, 14, 16 had reached the desired temperature and the LANETTE SX had been disolved in the petroleum jelly, the glycerine and petroleum jelly/LANETTE SX mixture were discharged from the tanks at such rates (adjustable via valves 24) so as to maintain, as far as possible, the same ratio by mass of glycerine and petroleum jelly in the tanks 12, 14, 16 as was provided initially.

The glycerine and petroleum jelly were gravity fed into the mixing tank 18 via the spiral mixer within the manifold 22.

When discharge from the tanks 12, 14, 16 was initiated, the pump 30 was started and thereby circulation of the glycerine/petroleum jelly/LANETTE SX mixture was initiated.

1 is Once the contents of the tanks 12, 14, 16 had been totally discharged into the mixing tank 18, the resulting mixture was circulated for approximately one hour. The mixture became lighter in colour and assumed a sheen as it was forced through the cylinder 32. It is believed that the relative narrowness of the pipe 30 through which the mixture was pumped as it returned to the tank 18, contributed to the lightening in colour.

After circulating for about one hour, the resulting product was left to stand for several hours, or at least until the temperature of the mixture in the mixing tank 18 had reduced to approximately 30 to 35'C.

Perfume was then added.

The mixture was allowed to cool to room temperature. It was left to stand during this cooling period except for a short time every couple of hours when mixing was effected by operating the pump 30 to circulate the mixture.

The emulsion product was in the form of a slightly tacky, soft grey to white gel which proved to be extremely stable. It was found, for example, that the product could be boiled and even heated to temperatures above 12CC without any perceptible separation of the constituents. On recooling to room temperature, the product in original form was identified.

16 Furthermore, freezing of the product for a number of days did not cause separation in either the frozen state or when it was returned to room temperature. Thus fluctuations in temperature did not adversely affect the stability of the product.

In other example in which inixing of the petroleum jelly and glycerine did not include subjecting the mixture thereof to friction and pressure similar to that which the mixture from tank 18 was subjected to when it was forced through the cylinder 32 and pipes 30, the colour of the emulsion product was darker, the texture was not as fine, and the sheen, if any, was greatly reduced.

The anhydrous product does not support bacterial growth and, furthermore, requires and contains no preservatives. Water may be added in quantities of up to 65% without requiring any preservative. This appears to be due to the preservative action of glycerine.

In its anhydrous or hydrous state, the product of the invention has extremely good skin moisturizing properties and can beneficially be applied to the skin or hair. It softens the skin and leaves it with a slight sheen which is particularly noticeable and attractive on darker skins. The glycerine constituents may have a skin lightening effect. It is believed that the product will prove to be particularly suitable for black 1 17 "Afro" hair styles in that it gels the hair and gives it a shiny black appearance.

The product is a boon to those suffering from dry skin conditions and restores dry, scaly or cracked skin, for example on heels, to a healthy, supple state.

The emulsion of the invention may further be used as a bath or shower gel. A user thereof spreads a small quantity over his body or face, adds water and rubs the resulting fine, milky lotion into the skin. The skin becomes soft, supple, but not greasy.

Creams comprising the emsulsion may include water in quantities of up to 60%, preferably up to 40% and more preferably 20% of the total mass of the first, second and third constituents of the emulsion. These creams may be used as nourishing or sun screen creams, or as vehicles for therapeutic active ingredients, for use as antiseptics, corticosterioids, etc.

Lotions are formed by adding water to the emulsion in quantities of 30 to 92%, preferably 30 to 50% and more preferably 40% of the total mass of the first, second and third constituents of the emulsion. A very smooth lotion is thereby provided and is can be used for similar applications as mentioned above f or the creams.

In short the emulsion according to the invention at least as exemplified, is a stable product which can easily be diluted with oil and/or with water to produce many dif f erent cosmetic or pharmaceutical preparations including f ace creams, hand and body lotions, hair care preparations, medicinal preparations in the forms of gels, creams and lotions and, when diluted with light oils, other products f or which it is desired to use a cream base which is free from preservatives. Even in its anhydrous state it has excellent moisturising properties. Furthermore it is nonallergenic and is relatiVely cheap and easy to prepare.

j K 4 19

Claims (17)

CLAIMS:

1. A stable emulsion which is substantially anhydrous and comprises first constituent which is a hydrocarbon wax, gel or oil; second constituent which is a polyhydric alcohol; and third constituent which is an emulsifying agent.

A stable emulsion which comprises first constituent which is a hydrocarbon wax, gel or oil; second constituent which is a polyhydric alcohol; third constituent which is an emulsifying agent; and water in an amount which constitutes not more than 60% by mass of the emulsion.

3. An emulsion as claimed in Claim 2, in the forn of a cream and comprising water in an amount which constitutes io-rom 0 to 40% by mass of the emulsion.

4. An emulsion as claimed in any one of lt-he preceding claims, wherein the emulsifying agent comprises at least one sulphated, higher alcohol having a carbon chain length of from C10 to C20.

5. An emulsion as claimed in any one of the preceding claims, wherein the emulsifying agent comprises ananionic emulsifying wax constituting approximately 1 to 14% of the total mass of the first and second constituents.

c

6. An emulsion as claimed in any one of the preceding claims, wherein the hydrocarbon wax, gel or oil comprises a petroleum jelly and the polyhydric alcohol comprises glycerine or sorbitol or propylene glycol.

7. An emulsion as claimed in any one of the preceding claims, which comprises the hydrocarbon wax, gel or oil and the polyhydric alcohol in the following proportions of the total mass of the first and second constituents: 10 to 40%: 60 to 90%.

8. An emulsion as claimed in any one of the preceding claims, which comprises petroleum jelly, glycerine and emulsifying wax BP in the following proportions of the total mass of the first and second constituents: 20 to 30%: 70 to 80%: 3.5 to 10%.

9. A pharmaceutical composition which includes a medicament and, serving as a carrier or vehicle therefor, an emulsion as claimed in any one of the preceding claims.

10. A method of' emulsifying a hydrocarbon wax, gel or oil.

and a polyhydric alcohol, which includes heating a hydrocarbon wax, gel or oil to a temperature of from 550C to 90OC; adding a suitable emulsifying agent to the hot hydrocarbon wax, gel or oil; heating a polyhydric alcohol to a temperature of from 55C to 90OC; and 9 0 21 mixing the hot polyhydric alcohol with the hot mixture of hydrocarbon wax, gel or oil and emulsifying agent to form a homogeneous mixture.

11. A method as claimed in claim 10, wherein the hydrocarbon wax, gel or oil is a petroleum jelly at a temperature of 75 to WC, the polyhydric alcohol is glycerine or sorbitol or propylene glycol at a temperature of 75 to WC, and the emulsifying agent comprises an anionic self-emulsifying wax..

12. A method as claimed in Claim 10 or Claim 11, which includes mixing together the hydrocarbon wax, gel or oil, the emulsifier and the polyhydric alcohol in the following proportions by mass based on the mass of the hydrocarbon wax, gel or oil and the polyhydric alcohol: 20 to 30%: 3.5 to 10%: 70 to 80%.

13. Use of an emulsion as claimed in any one of Claims 1 to 8, for preparing a substance or composition for application to the human skin or hair.

14. A substance or composition for cosmetic or therapeutic application to the human skin or hair, when prepared with an emulsion as claimed in any one of Claims 1 to 8.

15. A stable emulsion when prepared according to the method as claimed in any one of Claims 10 to 12.

16. A new stable emulsion, described and illustrated.

substantially as herein 22

17. - A method as claimed in Claim 10, substantially as herein described and illustrated.

Pablished 1990 atThe Patent Office. State House. 66'71 High Holoorn. London=lR 4'IT. Further copies nikybe obtainedfrom The Patent Office Sales Branch. St Mary Cray. Orpington. Kent BR5 3RD. Printed by techniques ltd. St Ma-y Cray. Kent. Con 187,