AU719304B2 - Antiperspirant compositions - Google Patents

Description

Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

(ORIGINAL)

9 a a a a a Name of Applicant: UNILEVER PLC Unilever House, Blackfriars, London, EC4P 4BQ UNITED KINDGOM DAVIES COLLISON CAVE, Patent Attorneys Level 10, 10 Barrack Street, Sydney, 2000 Address for Service: Invention Title: "Antiperspirant compositions" The following statement is a full description of this invention, including the best method of performing it known to me: (I J3332 1 ANTIPERSPIRANT COMPOSITIONS The invention relates to cosmetic products, such as antiperspirant and deodorant formulations, in particular to such products which are clear or transparent.

It has long been a goal in the formulation of antiperspirant and deodorant products to formulate transparent products.

This has been a problem particularly with gel and stick products, for which various approaches have been taken to try to formulate clear products.

Solid antiperspirant formulations generally fall within two broad categories suspensoid sticks and gelled alcoholic '15 sticks. Suspensoid sticks usually consist of acidic antiperspirant actives suspended in a matrix formed by a wax, in an emollient. Representative of this is US 4,431,837 (Geria), and US 4,126,679 (Davy et al). However, these sticks have the problem that the crystalline nature of the :20 wax matrix, and insolubility of the antiperspirant active render the stick opaque.

Gelled alcoholic sticks may be formulated in either of two ways. One method is to use an alkaline aluminium chlorhydrate-lactate complex as the active, and gel this with sodium stearate. Illustrative of this are US patents 3,472,940 (Osipow et al), and US 3,259,545 (Teller).

Alternatively, dibenzaldehyde monosorbitol acetal (DBMSA) can be used to structure an alcohol soluble antiperspirant active as illustrated in US 4,518,582 (Schamper et al) and EP 512,770 (Benfatto et al). These approaches have found limited success, in that clarity can be achieved, but the formulations suffer certain disadvantages.

J3332 2 Antiperspirant gel sticks made using soaps experience problems associated with interaction between the basic soap solidifying agents and the acidic antiperspirant actives.

This interaction can result in poor gel formation, reduced efficacy of the actives, and lower stability over time of any gel formed. Furthermore, the alkaline aluminium activelactate complex active gelled with sodium stearate is not particularly effective, because such actives intrinsically have low efficacy.

The gel sticks made using DBMSA are preferred, as these readily produce transparent sticks. However DBMSA is unstable in the presence of acids and hydrolyses to form benzaldehyde, which results in loss of structuring ability.

Indeed, improving the stability of DBMSA gels has been the goal of many patent applications over the past decade. In addition to the stability issue, DBMSA gels tend to suffer from poor sensory properties, such as excessive stickiness.

Other methods of formulations clear antiperspirant gel sticks without the use of soap or DBMSA are described in the literature. In EP 448,278 (Colgate-Palmolive), there are disclosed formulations of a clear antiperspirant gel stick comprising an aqueous antiperspirant solution, a complexing "'25 agent and a hardeningagent. In EP 373,499 (Colgate- Palmolive) there is described a clear antiperspirant gel stick comprising an aqueous antiperspirant active solution, insoluble volatile emollients, coupling agents, a solubilizer and a water thickening agent. In EP 396,137 (Gillette) there is disclosed a clear anhydrous antiperspirant composition comprising an antiperspirant active of very specific refractive index, matching that of the cosmetic vehicle.

In US 4,948,578 (Burger et al) there is disclosed an antiperspirant stick comprising an antiperspirant active, a r\ J3332 3 nonionic surfactant, liquid oil and water. Transparency is achieved by matching the refractive indices of the aqueous and oil phases.

Although transparent forms can be achieved using these methods, these formulations suffer certain disadvantages.

For example, the gels formed suffer from low efficacy, and additionally some other poor characteristics such as poor sensory properties, and insufficient rigidity for a commercial product. Also, to form acceptable commercial products, certain technical solutions as presented in the literature require the use of further specific process steps.

An example of this is refractive index matching, which is oooe required to obtain transparent gel sticks as disclosed in EP .39.6137 arind US 4,948,578.

A further problem in particular with the compositions described in US 4,948,578 (Burger et al) is that it has not been possible to incorporate zirconium containing salts, a ~0 known and highly efficacious form of antiperspirant active, into such compositions. Attempts to incorporate zirconium aluminium salts into a transparent antiperspirant gel product containing oil, water, and 10-40% of a polyoxyethylene nonionic surfactant were unsuccessful, (see column 3 lines 7- 10 of US 4,948,578) the zirconium antiperspirant salts being *incompatible with the remainder of the vehicle.

It is an object of the invention to provide stable transparent antiperspirant products in gel/stick form, which overcome some or all of the problems of the prior art. In particular, it is an object of the invention to provide stable transparent antiperspirant gel compositions which are stable and have good sensory properties.

4 It is a further objective of the invention to provide a stable transparent, antiperspirant gel compositions containing zirconium-containing salts as the antiperspirant active, and a compatible nonionic surfactant.

Thus, according to a first aspect of the invention, there is provided a transparent structured microemulsion antiperspirant composition in the form of a gel, which comprises water, a zirconium-containing salh having antiperspirant activity, and 5-70% of a nonionic polyhydroxy surfactant.

Preferably, the composition additionally comprises a liquid oil, such as a mineral oil.

bee The product form according to the invention is a gel, which typically has a viscosity of 50,000 cps or more at 21 0 C. In addition, the structured microemulsion product is thermodynamically stable, as small droplets are formed spontaneously. Transparency can therefore be achieved readily without matching the refractive indices of the phases of the emulsion.

As taught by the literature, in particular the Burger patent referred to above (US 4,948,578) it was not conventionally thought possible to formulate a transparent emulsion antiperspirant gel stick using nonionic alkoxylated surfactants and antiperspirant actives which contain zirconium.

However, we have discovered that a certain class of nonionic surfactants, namely the polyhydroxy class, may be compatible with zirconium aluminium antiperspirant salts. As such, these surfactants can be used to incorporate satisfactorily zirconium containing antiperspirant active salts into an inherently transparent water and/or oil containing single phase liquid crystal matrix. The resulting composition is stable and clear.

The polyhydroxyl nonionic surfactants used in compositions according to the invention may be present at a level of more preferably 10 to 60%, more preferably 10 to 40% by weight of the composition.

Preferred polyhydroxylnonionic surfactants when used in the present invention should be capable of forming clear or translucent ordered liquid crystalline phases in the presence of water.

e* 1 Particularly. desirable are surfactants which form viscous S isotropic (cubic) phases upon the addition of water and/or oil. Furthermore, there must be no interaction between the surfactant and the zirconium containing antiperspirant active salts in manner which is likely to lead to precipitation, as is typically the case with the nonionic ethyoxylated surfactants class.

The polyhydroxylnonionic surfactants suitable for the present invention include, for example, surfactants derived from carbohydrates known under the generic names alkyl glucosides, alkyl polyglucosides, fatty acid sugar esters, glucosyl alkyls, methyl glucoside esters, sucrose esters, sugar esters, sorbitan esters, ethyl glucoside ester, alkyl maltosides, polyglycerol esters, aldonamides (N-alkyl lactobionamide), aldosamides, succinimides, N-alkanoyl-Nmethyl glucamides, alkanoyl ethyl glucosides, alkyl polyglycerol ethers and alkylidene polyglycerols.

Preferred polyhydroxyl surfactants used in the composition to RA vructure the aqueous phase are sucrose esters, polyglycerol r 0 J3332 6esters or alkyl polyglycerol ethers.

Preferred sucrose esters for use according to the invention have the following structure;

CH

3

(CH

2 )n COOCH, H H HOH 2 C 0 OH H OH H OH CH 2

OH

H OH OH H wherein n 7-25, preferably 10-20.

.51 Preferred sucrose esters include sucrose myristate (n=13), which is commercially available from Mitsubishi Kasei, and sucrose isostearate (n=17, branched). It is highly preferred that the alkyl chain on the sucrose ester is branched as an 20 isostearyl, or unsaturated as in oleyl, as it lowers the melting point of the surfactant and the concomitant formation of liquid crystalline phases. Such esters can be made by standard synthesis techniques, for example by interesterifying methyl esters of appropriate fatty acids with sucrose in methanol under alkaline conditions, the methanol being subsequently removed.

A further preferred category of suitable polyhydroxyl nonionic surfactants for use according to the invention are polyglycerol esters. Preferred polyglycerol esters have the following structure;

CH

2

OH-CH

2

OH-CH

2

[CH

2 -CHOH-CH,] n-O-CH 2

-CH

2

OH-CH

2 -OCO- (CH 2 y-CH 3 wherein; *J3332 7 n is between 0 and 20, preferably between 4 and 10, most preferably 8.

y is between 10 and 25, preferably between 15 and with this part of the chain most preferably being branched or unsaturated.

The glycerol moiety can conveniently be (poly)glycerol isomers resulting in either a linear or branched glycerol moiety.

The alkyl (CH 2 )y moiety can conveniently be branched or unbranched, and may be unsaturated. Particularly preferred polyglycerol esters include hexaglycerol monooleate, (n=4, y=17, unsaturated), and decaglycerol monoisostearate (n=8, y=17, branched).

Such surfactants can be made by well known synthesis techniques, such as esterification of the desired 20 polyglycerols and the appropriate fatty acids. The polyglycerols themselves may be synthesised by the polymerisation of glycerol and sodium hydroxide.

The term "transparent" as used herein is intended to connote its usual dictionary definition. Hence a composition under ""the invention which is transparent will readily allow viewing of objects through it. This is in contrast to a translucent product, which will allow light to pass through it, but in doing so causes sufficient scattering of that light, such that it is not possible to view objects clearly through a sample of the product. Alternatively, the product may conveniently have an optical clarity better than 50 NTU (Nephelometric Turbidity Units) when measured at 5893A at 21 0 C. Turbidity measurements can conveniently be made with a Orbeco-Hellige #965 Direct Reading Turbidimeter.

J3332 8 The liquid oil used in compositions according to the invention is conveniently present at a level of 5 to 50% by weight of the composition, more preferably 10 to 40% by weight.

The liquid oil component may itself be composed of emollient oils, volatile silicones, and preferably mixtures thereof.

Emollient oils are defined as liquids at room temperature being immiscible with water (and preferably miscible with volatile silicones). Among the emollients oils may be included linear and branched chain fatty acid esters, diesters of dicarboxylic acids, and liquid hydrocarbons.

Examples of fatty acid esters include the isopropyl esters of 6: myristic, palmitic and stearic acids. Branched chain fatty *:15 acid esters -are illustrated by 2-butylhexylpalmitate and 2ethylhexyloxystearate. Di-n-butyl phthalate and diisopropyladipate are exemplative of dicarboxylic acid diesters. Mineral oils and paraffins, such as are available from Exxon under the Trade Mark Isopar, are illustrative of 20 suitable liquid hydrocarbons. Most preferred among the emollient oils is 2-ethylhexyloxystearate (the 2-ethylhexyl ester of a hydroxystearic acid) which is available as •Wickenol 171 from the CasChem Corporation. The amount of emollient oil present will usually be from about 2 to preferably from about 5 to 15% by weight of the composition.

Volatile silicones may be used as a liquid oil in compositions according to the invention, and may be present to assist in detackifying the composition. These materials also provide a dry, non-oily lubricant effect when the gel or lotion is applied to the skin. Volatile silicones are relatively low molecular weight cyclic siloxane oligomers.

The most readily available species of these siloxanes are hexamethyl- cyclotrisiloxane (boiling point 134 0

C),

octamethyl- cyclotrisiloxane (boiling point 175.8 0 C) and J3332 9 15 25 decamethylcyclopentasiloxane (boiling point 2100C), more commonly know as trimer (D 3 tetramer (D 4 and pentamer respectively. The D 4 and D, materials are also known, under the terminology of the Cosmetics, Toiletry and Fragrance Association, Inc (CTFA) as "Cyclomethicone". Commercially the D 5 cyclomethicone is available from Union Carbide Corporation as VS7158 and as DC344 from Dow Corning Corporation. The amounts of volatile silicone in the present compositions, if used at all, will usually range from about 0 to 30%, preferably from about 10 to 20% by weight.

Compositions according to the invention may additionally comprise a co-surfactant, which may be present at a level of upto 20% by weight of the amount of nonionic surfactant included in the composition. .Such. a cosurfactant will in this case be a nonionic surfactant, and will have a similar composition and structure to the essential nonionic surfactant of the composition, but will differ to a small degree almost certainly in either the size of headgroup, or chainlength. The co-surfactant needs to be compatible with the essential nonionic surfactant of the composition, but will act to modify the curvature at the water/oil interface, and thereby aid the formation of the liquid crystal phase.

The antiperspirant active in the composition can be any zirconium containing antiperspirant active salt. The zirconium compounds which may be used in the present invention include both zirconium oxy salts and zirconium hydroxy salts, also referred to as the zirconyl salts and zirconyl hydroxy salts. These are preferred compounds for use herein and may be represented by the following general empirical formula: ZrO(OH) 2 nzB, J3332 10 wherein z may vary from about 0.9 to about 2 and need not be an integer; n is the valence of B; 2-nz is greater than or equal to 0; and B may be selected from the group consisting of halides (preferably chloride), nitrate, sulfamate, sulfate, and mixtures thereof.

Several types of antiperspirant complexes utilizing the above antiperspirant salts are known in the art. For example, US Patent 4,120,948, Shelton, issued October 17, 1978 and US Patent 3,792,068, Luedders et al., issued February 12,1974, both of which are incorporated by reference, disclose complexes of aluminum, zirconium, and amino acids such as glycines. These complexes and other similar complexes with glycine amino acids are commonly known as ZAG complexes.

5 .Suitable ZAG complexes may-be identified by the specification of both the molar ratio of aluminum to zirconium (hereinafter S* "Al:Zr" ratio) and the molar ratio of total metal to chlorine (hereinafter "Metal:Cl" ratio). Suitable ZAG complexes have an Al:Zr ratio of from about 1.67 to about 12.5, and a 0 metal:Cl ratio of from about 0.73 to about 1.93.

Also useful are the ZAG complexes disclosed in G.P. Patent Application 2,144,992, Callaghan et al., published March 1985. These ZAG actives, when analyzed by high pressure gel 25 permeation chromatography, exhibit a distribution pattern having four or more successive peaks or "bands" where the height ratio of Banks IV to III is greater than 2:1.

More preferred are ZAG actives which have a total area under the curve of bands I and II of less than about preferably less than about more preferably less than about 2% and most preferably less than about 1%.

Preferred ZAG complexes can be formed by J3332 11 co-dissolving in water one part Al 2

(OH)

6 wherein Q is an anion selected from the group consisting of chloride, bromide, and iodide; and m is from about 0.8 to about x parts ZrO(OH)2-aQanH 2 O, where Q is chloride, bromide, or iodide; a is from about 1 to about 2; n is from about 1 to about 8; and x is from about 0.16 to about 1.2; p parts neutral amino acid selected from the group consisting of glycine, dl-tryptophane, dl-P-phenylalanine, dl-valine, dl-methionine, and P-alanine, 15 and where p is from.about 0.06 to about 0.53; co-drying the resultant mixture to a friable solid; and reducing the resultant dried inorganic-organic '"20 antiperspirant complex to a particulate form.

A preferred aluminum compound for preparation of such ZAG type complexes is aluminum chlorhydroxide of the empirical formula Al 2 (OH) 5 C12H 2 0. Preferred zirconium compounds for preparation of such ZAG-type complexes are zirconyl hydroxychloride having the empirical formula ZrO(OH)Cl-3H 2 0 and the zirconyl hydroxyhalides of the empirical formula ZrO(OH)2-aCl 2 nH20 wherein a is from about 1.5 to about 1.87, and n is from about 1 to about 7. The preferred amino acid for preparing such ZAG-type complexes is glycine of the formula CH 2

(HN

2 )COOH. Salts of such amino acids can also be employed in the antiperspirant complexes. See US Patent 4,017,599, Rubino, issued April 12, 1977, incorporated herein by reference.

12 Included are co-salts of zirconium and aluminium. Preferred zirconium containing salts include Rezal 36GP, Rezal 36, and Rezal 67P, ex Reheis.

Preferably the antiperspirant active is present in the composition at a level of 5 to 25%, preferably 10 to 20% by weight.

Water is also an essential element of the composition. It must be present at a level of 5 to 50%, preferably 25 to by weight.

Other optional ingredients may be present in the composition.

These may include perfumes, preservatives, colourants, antimicrobial agents, short chain monohydric alcohols, and other ingredients routinely used in such cosmetic products.

S

Experimental Comparative Example 1 A cosmetic base was prepared by high speed shearing of water, oil, and a surfactant to prepare a transparent single liquid crystal phase gel, according to the following compositions.

COMPOSITION

W/W)

1 2 Oil phase 10 20 Water 50 45 Surfactant 40 35 made up of equal weights of octyldodecyl alcohol, ,411- Rcyclomethicone, and octyldodecyl myristate.

13 Polyoxyethylene (20) octyl dodecyl ether The addition of as little as 1% of a zirconium aluminium antiperspirant active Rezal 36GP, ex Reheis) caused the opacity of the second phase of the emulsion; as a result the composition became cloudy.

Comparative Example 2 Liquid crystals based on glycerol monooleate, oil and water were made as described in EP 550,960 (Unilever N.V. et al).

The nonionic surfactant in this, glycerol monooleate, is a monohydroxy species. It was found that no zirconium aluminium antiperspirant active materials could be 5 incorporated into these liquid crystal phases- as the Szirconium aluminium active Was incompatible with the monohydroxy nonionic glycerol monooleate.

Example 3 The compositions as described in the following tables were prepared by mixing together and heating (if necessary) at high shear the components. All the compositions resulted in a transparent liquid crystal phase.

S

S

C

C-

5

C

*5S *C* 5 5-

S

~5

C

S. ~i S 0 V sip of.

COMPOSITION (6w/w) Componentfl 1 2 3 4 5 6 7 8 9 zirconium/aluminium salt 5.0 10.0 10.0 15.0 10.0 5.0 10.0 25.0 (Rezal 36 GP,ex Reheis) Water 25.0 20.0 30.0 20.0 31.5 19.0 40.0 30.0 33.25 Mineral Oil (dodecane) 5.85 15.2 14.25 Isostearyl alcohol Surf actant Diglycerol monooleate 70.0 Hexaglycerol monooleate 70.0 60.0 65.0 52.65 60.8 DecaglyCerol 50.0 45.0 47.5 ronoisostearate S.

S

S

S

i S ~0

S

5S* 555 i.

S *I S. S je S.

Si. *iO* 5 0 5* *t 55 S S S *S S S S 55 S S S Si S S S COMPOSITION Wlw) Zirconium/aluminium 5.0 30.0 20.0 10.0. 5.0 15.0 30.0 5.0 10.0 salt (Rezal 36 GP,ex Reheis) Water 38.0 30.0 20.0 20.0. 14.25 25.0 30.0 33.25 27.0 mineral oil (dodecale) 5.7 30.875 31.5 Isostearyl alcohol 28.5 Surf actant Decaglycerol 51.3 monoisostearate Sucrose Myristate 40.0 60.0 70.0 52.25 Sucrose MonoiSostearate 60.0 40.0 30.875 31.5 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

e

Claims (3)

1. A transparent antiperspirant compositionl in the form of a gel having 'a liquid crystal structure, comprising water, a zirconlium~ containling salt having antiperspirant activity, and 5-70.% by weight of a nonionic polyhydroxYl surfactant.

2. A composition according to claim 1, wherein the nonionic surfactant is a sucrose ester, a polyglycerol ester, or an alkyl polyglycerol ether. A opsto coding to claim 2 wherein the sucrose ester has the structure; 'H3 (CHI)1 COOCH 2 0-HOHC 0 ko 2H 0:H~ OR CH 2 0OH H OH p.OH H wherein n =7-25, preferably

10-20. 4. A composition according to claim 2 wherein they polyglycerol ester has the structure; CH 2 OH-CH2 HCH 2 O0 [CH 2 -CHOH-CH 2 1 n-O-CH2 -CHQHCH2 -OCQ (CHO) 3 wherein; 17 n is between 0 and 20, and y is between 10 and 25, with this part of the chain most preferably be branched or unsaturated. 5. A composition according to any of the preceding claims, additionally comprising a liquid oil. 6. A composition according to any of the preceding claims, additionally comprising a cosurfactant. 7. A composition according to any one of the preceding claims in which the zirconium-containing salt further comprises aluminium. 8. A transparent antiperspirant composition substantially as described herein with respect to any one of compositions 1 to 18 in example 3. Dated this 3rd day of March 2000 1Unilever Australia Ltd "By its Patent Attorneys of Davies Collison Cave