WO1994014408A1

WO1994014408A1 - Deodorant composition

Info

Publication number: WO1994014408A1
Application number: PCT/EP1993/003615
Authority: WO
Inventors: Andrew Martin Creeth; Gordon Robert Wight
Original assignee: Unilever Plc; Unilever N.V.
Priority date: 1992-12-22
Filing date: 1993-12-17
Publication date: 1994-07-07
Also published as: ZA939619B; AU5813894A; GB9226684D0

Abstract

Deodorant compositions for topical applications to human skin, e.g. underarm, contain as active agent a layered hydroxide which contains copper and at least one other metal, and has the crystal structure of spangolite. Such a material may comply with a general formula: CuxZnyTi(OH)12R2.nH2O, where R is one or a mixture of divalent anions, the sum of x and y is 6 and n ranges from 1 to 6.

Description

DEODORANT COMPOSITION FIELD OF THE INVENTION

This invention relates to deodorant actives, and to new compositions containing these deodorant actives which are suitable for topical application to the human skin. BACKGROUND OF THE INVENTION

The deodorant market is dominated with products which rely for their deodorancy effect either on ethanol, or various other metal salts. For example, in EP 024 176 (Unilever), there is described a deodorant composition containing as an active ingredient zinc carbonate. The composition is an aerosol composition which is designed to reduce

axillary odour without suppressing perspiration, and also comprises a water-absorbent anionic polyelectrolyte. There still exists, however, demand for deodorant

compositions, which may be used on their own or as part of a combined antiperepirant/deodorant composition, which provide a superior degree of efficiency in terms of their ability to control odour generation, in relation to conventional deodorant or antiperspirant/deodorant compositions. Conventional compositions may also have associated consumer and/or sensory negatives, which ideally can be improved upon. Spangolite is a mineral which occurs naturally, although it is rare. It was first reported by C.Frondel in Amer. Miner, 34, 181 (1939). The mineral was named after Norman Spang, its discoverer. The mineral has the general formula;

Cu₆Al (OH)₁₂ClSO₄.3H₂O. (I)

From X-ray diffraction data, the mineral is believed to have a layered structure related to hydrotalcite minerals

Hydrotalcite materials as such are described in "Anionic clay materials" by W T Reichle, Chemtech, January 1986 pages 58-63. Such minerals are anionic clays, and have a structure broadly similar to brucite (magnesium

hydroxide). In this structure, magnesium atoms are octahedrally surrounded by six oxygen atoms in the form of hydroxide, the octahedra sharing edges to form an infinite sheet. The sheets are generally stacked on top of each other, and linked by hydrogen bonds. However, although they are based on this brucite structure, hydrotalcites are materials in which aluminium cations have replaced some of the magnesium cations. Because there is an additional unit of positive charge for every aluminium cation that substitutes for a magnesium cation, such materials therefore have located between the metal hydroxide sheets further anions, which maintain the electrical neutrality of the structure. As a result, a hydrotalcite may have a large range of anions associated with it.

Spangolite has a layered structure, as does hydrotalcite, but differs in that the associated anions are bound in the layers rather than being located in between the layers.

In contrast to the rarity of spangolites in nature, it has been found that a range of materials which are

isostructural with spangolite can be prepared

artificially.

SUMMARY OF THE INVENTION

We have now discovered that materials which are

isostructural with spangolite may be included in deodorant or antiperspirant compositions, and may provide a

surprisingly good degree of efficacy in terms of their ability to control and/or reduce odour, when compared to such notable deodorancy standards as compositions

containing zinc carbonate.

Broadly, according to this invention, there is provided a deodorant composition suitable for topical application to the human skin, comprising a layered hydroxide

incorporating copper and other metal and which has the crystal structure of spangolite, in a physiologically acceptable carrier.

It is particularly envisaged that other metal in this layered hydroxide will include both zinc and a metal with valency three or four. In another aspect the invention provides the use of a copper-containing layered hydroxide as defined above to inhibit human body odour, notably by application to skin of a composition as defined above. DETAILED DESCRIPTION

The active ingredients of compositions of this invention are layered hydroxides in which copper is present along with other metal, and which have the structure of

spangolite.

Preferred materials are of general formula

Cu_xZn_yTi(OH)₁₂R₂.nH₂O (II)

wherein R is one or a mixture of divalent anions,

especially sulphate or carbonate, the sum of x and y is 6, x and y being any number or fraction greater than 0 and smaller than 6, and n is any number varying from 1 to 6. Preferably, x ranges from 1.5 to 4 and y ranges from 4.5 to 2. Preferably, the ratio of y:x varies from 1-3.

Materials of the general formula (II) above have a layered crystal structure, and are isostructural with the mineral spangolite.

Preferred spangolite-type materials of the type generally described above, when incorporated in physiologically acceptable carriers, surprisingly provide a remarkably good degree of odour control and deodorancy. Such minerals may be prepared by mixing an aqueous solution of copper salts, zinc salts and titanium salts with an alkaline aqueous solution of alkali metal hydroxide, optionally with an alkali metal carbonate, heating the result and filtering, and washing and drying the result.

Such a preferred material is a copper zinc titanium synthetic analogue of spangolite, that is one in which some or all of the aluminium in the mineral is replaced with titanium, and some of the copper is substituted with zinc. Particularly preferred copper zinc titanium

synthetic spangolite has the general formula: (Zn+Cu)₆Ti(OH)₁₂(SO₄)₂.nH₂O. (Ill)

Preferably, the ratio of Zn:Cu lies in the region 1:1 to 3:1. Copper zinc titanium synthetic spangolites of this general formula demonstrate a similar powder X-ray

diffraction pattern to natural spangolite, and are further described in our co-pending European application published as EP-A-547666 on 23 June 1993, the content of which is incorporated herein by reference.

Typical examples of these materials which may be used in compositions according to the invention are

Cu₃Zn₃Ti(OH)₁₂(SO)₄)₂.3H₂O, and Cu_1.6Zn_4.4Ti(OH)₁₂(SO₄)₂.3H₂O.

In a preferred form, the synthetic spangolite demonstrates two types of crystallites, some being platelets as large as 0.4 microns diameter, but also other material which is microcrystalline and is as small as 50 angstroms.

Without wishing to be bound by theory, it is thought that the mineral functions as an underarm deodorant by

dissolving slowly in the low pH environment of the axilla, thereby releasing metal ions which provide an

antimicrobial effect.

When used in such compositions, preferably the synthetic spangolite has a platelet diameter of less than about 0.4 microns.

Compositions according to the invention will generally contain 0.01 to 30% by weight, preferably 0.05% to 20% by weight, more preferably 0.1% to 10% or 15% by weight of the synthetic spangolite analogue.

The physiologically acceptable carrier which is a

component of compositions of this invention should be acceptable for topical application to human skin.

Various materials may be used as the carrier, depending on the form of the product. Notably, compositions according to the invention can take the form of liquid or solid products, suitable for topical application to the human skin, especially the underarm.

A convenient product form is a solid stick, usually contained in a suitable holder or dispenser to enable it to be rubbed onto an area of the skin, in particular the underarm, where control of perspiration or de'odorancy is required. An alternative and preferred form of compositions

according to the invention is a lotion, containing the synthetic spangolite in suspension, which is suitable for example for application from a roll-on dispenser. Such a dispenser enables the product to be rolled onto the skin in an area where odour control is required, which is a conventional manner of application known in the art. A further example of a suitable composition according to the invention is a liquid composition for dispensing from an aerosol can pressurized with a volatile propellant. Another, somewhat similar example is a liquid composition for dispensing via a finger operated pump spray to provide for delivery to the skin of a finely divided spray or aerosol, without the use of propellant gas to deliver it.

A composition in the form of a stick may be based on a waxy organic solid or a very viscous gel as carrier material. Commonly such a gel comprises ethanol or aqueous ethanol thickened to form a gel with sodium εtearate or other hard soap. Sticks may be based on propylene glycol and on mixtures of alcohol and glycols. These may be gelled by incorporation of dibenzyl sorbitol. Volatile silicone may be gelled to a stick with stearyl alcohol. A material to improve skin feel, such as

glycerol, may be included in a stick. Waxes and talc are also frequently included.

A lotion for application from. a roll-on dispenser may use a variety of liquids as carrier material. Water may possibly be used, so also may hydrophilic organic liquids such as ethanol, and hydrophobic organic oils. Ethanol and aqueous ethanol containing at least 40% ethanol are commonly used. Usually the liquid phase contains an emollient material which provides desirable skin feel properties, e.g. isopropyl myristate, cetyl alcohol or di- butyl phthalate. A thickener may be included to increase the viscosity of the composition and maintain the solids in suspension. A composition for delivery as an aerosol will generally include alcohol, aqueous alcohol or volatile silicone oil as carrier material in addition to any propellant.

For compositions which are aerosols or sprays, the layered double hydroxide is preferably in the form of single or aggregated plates with a minimum diameter of 1 micron, better at least 5 microns.

For other compositions which are not delivered by

Bpraying, smaller plate sizes may well be used, e.g. down to 0.03 microns. For any composition it will be desirable that the plates have diameters of not more than 100 microns, better not over 75 and even better not over 20 microns.

It should be noted that compositions according to the invention are suitable not just for application to the axilla, but may be applied to any surface of the body at which the control of odour may be required, such as the foot or crotch.

Ingredients which can be present in compositions according to the invention inulude: - cosmetically acceptable vehicles, such as straight and branched chain alcohols, for example, ethanol, isobutanol or isopropanol; - volatile and non-volatile silicones, such as dimethyl cyclosiloxanes or polydimethyl siloxane,

eg, DOW CORNING fluids DC244, DC245, DC344, DC345, Q2 1465 and the 200 fluids; - antiperspirant active salts, such as those of

aluminium or zirconium; - deoperfumes and deodorant compounds which can act as antimicrobial agents; - hydrophobic oils, such as liquid paraffin oils; - inorganic electrolytes, such as sodium chloride or sodium sulphate; cationic polymers, such as Abil Quat 3272 and Abil Quat 3270, both ex TH Goldsmidt AG; - thickeners such as clays, for example, Bentone 38, silicas, for example, Aerosil 200 and hydroxypropyl celluloses such as Klucel; - skin feel improvers, such as talc and finely divided polyethylene, an example of which is Acumist B18; - gelling agents, such as stearyl alcohol, sodium

stearate or waxes, for example castor wax; - humectants, such as polyols, for example glycerol; - water; - emollients such as isopropyl myristate; - perfumes; - preservatives and antioxidants; - skin benefit agents, such as allantoin; - colours; - other cosmetic adjuncts conventionally employed in stick, roll-on lotion, liquid spray, cream and propellant driven aerosol products. It should be appreciated that a number of the above ingredients do not contribute to the deodorant function but are present to give other benefits and acceptability to the consumer. The ingredients above may conveniently form up to 99.95% by weight of the composition, more preferably up to 99.9% by weight of the composition. Compositions of the invention will generally contain a majority of water, organic liquid or a mixture of the two. Frequently the amount will lie in a range from 75 to

99.99% by weight. The amount of organic liquid present may be quite small, but at least 5% by weight will

generally be present. Organic liquid may be present in much larger amounts, up to 99.99%, since water may be entirely absent. EXAMPLES

The invention will now be described by way of example only.

Method

A copper zinc titanium synthetic spangolite of the type described above was made by the following method.

Solutions of 8.99g of CuSO₄.5H₂O in 100 ml water, 31.05g ZnSO₄.7H₂O in 100ml water and 37g of a 15% solution of Ti(SO₄)₂ in 100ml water were mixed together. The mixture was stirred at 2000 rpm with an overhead stirrer and 155ml of a 2M NaOH solution added via a dropping funnel. The result was placed in an oven at 95°C for 40 hours, and the product filtered, washed with water, and dried overnight at 95°C. The composition was determined by analysis to be Cu_1.6Zn_4.4Ti(OH)₁₂(SO₄)₂.3H₂O The powder X-ray diffraction pattern was the same as that given in Example 2 of EP-A-547666 and confirmed a structure analogous to that of natural spangolite.

Analogous compositions with different ratios of copper to zinc can be prepared by varying the ratio of copper and zinc salts in the above preparative method.

The preparation of Zn₃Cu₃Ti(OH)₁₂(SO₄)₂.3H₂O by a similar method is described in EP-A-547666 incorporated herein by reference.

Example 1

A composition containing the above synthetic spangolite analogue was prepared with the formulation tabulated below. A comparative composition contained zinc

carbonate.

(1) As prepared above.

(2) zinc carbonate hydroxide monohvdrate powder, ex BDH

(3) ex Dow Corning

(4) a hydrophobed clay, dimethyl distearyl ammonium hectorite ex Rheox.

Composition 2 was provided for comparison only.

Compositions 1 and 2 were made up by simply blending together the components of the composition at high shear. The compositions were lotions, and were packaged in roll- on applicators.

The effectiveness of the compositions was assessed by following procedure. Results are given in Table 1 below.

Test Protocol

The test protocol uses a team of 3 experienced trained expert assessors. The teβt panel used between 15 and 17 female volunteers, and malodour was assessed on an increasing scale of 0-10. Procedure

On the first day of the test, the panellists' axillae are washed with unperfumed soap. Panellists are allocated a different product for each axilla, which is applied as a fixed weight (approx. 300mg) on any given occasion. After 8 and 24 hours of wear of the test product on each application, the odour intensity of each axilla is evaluated by each assessor in turn, assigning an odour intensity score. A preliminary test with a placebo composition free of any deodorant active was carried out for 8 hours to give a base line value of odour intensity.

After each assessment, the panellists are washed and the products reapplied. The protocol is repeated over four successive days.

The dosage applied on any occasion was determined by weighing the product container before and after

application.

The differences between composition 1 and composition 2 were not large enough to be statistically significant at a 95% confidence level. It can be seen from the results that composition 1 containing the copper zinc titanium mineral provided a substantial level of deodorancy which was approximately equal to that of composition 2, a standard which contained zinc carbonate in an amount which was eight times greater. Example 2

Further compositions tabulated below were prepared and tested using the same protocol as that described above, except that a panel of 14 subjects was used, assessment was on a scale of 0-5, and assessments were made after 24 hours on two consecutive days.

This result indicated that, in this test, the copper zinc titanium synthetic spangolite compositions exhibited an equivalent deodorancy effect to the zinc carbonate- containing control. This test was significant at a 95% level of confidence.

Example 3

This used the same test protocol as example 2, except that assessments were made 7 hours after application on each of three successive days, on a mixed sex panel of 17

panellists.

Component Composition (wt %)

5 6

Copper zinc titanium spangolite (1) 1.0 - Silicone DC344 (3) 94.5 92.0 Anhydrous ethanol 1.0 2.5 Demineralised water 0.5 0.5 Bentone 38 (4) 3.0 5.0

Results

Composition Mean malodour Mean

score Deposit (mg)

5 1.43 339

6 1.91 347

This example clearly shows that the deodorant effect provided by the compositions is due to the mineral in the composition, and not another component of the vehicle. This result is significant at a level of greater than 99.9%

Example 4

Volatile silicone aerosol deodorant sprays have the following composition: wt %

Copper zinc titanium spangolite 0.1 to 1.0 Volatile silicone oil (Dow Corning DC 244) 9

Bentone 38 0.5

Ethanol 0.5

Butane balance to 100%

The butane functions as propellant, giving a pressure of 3.2 bar.

Example 5

Two alcoholic aerosol sprays have the following

compositions: wt %

Copper zinc titanium spangolite 0.1 1.0

Ethanol 48.9 48

Butane 50 50

Perfume 1.0

Isopropyl myristate 1.0

The butane functions as propellant, giving a pressure of 3.2 bar. Example 6

Two further aerosol sprays have the compositions: wt %

Copper zinc titanium spangolitee 1.0 1.0 Water 20 20

Perfume 0.5 1.5

Dimethyl ether propellant 50 50

Ethanol balance to balance to

100% 100%

Aerosol composition are prepared by first making a suspension concentrate by blending and homogenising all the ingredients except the propellant. The concentrate is placed in a container which is then sealed with a suitable aerosol valve and pressurised with the propellant.

Example 7

A composition based on volatile silicone oil, suitable for filling into roll-ball applicators, has the composition:

wt %

Copper zinc titanium spangolite 1

Bentone 38 1 to 5

Perfume 0 to 2

Alcohol 0.5

Volatile silicone oil balance to 100%

(Dow Corning DC 345) Example 8

Two alcoholic compositions for roll-ball applicators are: wt %

Copper zinc titanium spangolite 1 1

Perfume 0 to 2 0 to 2

Hydroxypropyl cellulose thickener 0 to 1 0 to 1 (Klucel M from Avalon/Hercules)

Ethanol 80 20

Water balance to balance to

100% 100%

Example 9

Three compositions for delivery from pump sprays are:

Wt%

Copper zinc titanium spangolite 1 1 1

Perfume 1 . 5 2 1 . 5

Isopropyl myristate 0 . 5 1 1

Ethanol 75 25 86 . 5

Water to 100 to 100 -- Volatile silicone oil -- -- -- (Dow Corning Q2 1465) Example 10

This is a deodorant product in the form of a stick, containing:

wt %

Copper zinc titanium spangolite 1

Stearyl alcohol 30

Castor wax MP80 1

Perfume 2

Volatile silicone oil DC 345 66

Example 11

Further examples of stick are:

wt %

Copper zinc titanium spangolite 1 1

Sodium stearate 6 6

Perfume 2 2

Ethanol 81

-- Water 10 31

Propylene Glycol -- 60

Example 12

A product in the form of a deodorant cream is:

wt %

Isopropyl myristate 10.00

Mineral oil 15.00

Cetyl alcohoi 2.00

Ethoxylated cetyl alcohol (20EO) 0.50

Copper zinc titanium spangolite 1.00

Glycerine 2.00

Propyl paraben 0.10

Methyl paraben 0.20

DMDM hydantoin 0.20

Water to 100 Example 13

A composition in the form of an emulsion suitable for filling into roll-ball applicators is:

wt %

Glyceryl tricaprylin 5.00

Steareth-21* 1.00

Steareth-2* 2.50

Copper zinc titanium spangolite 1.00

Propyl paraben 0.10

Methyl paraben 0.20

Phenoxyethanol 0.40

Water to 100

* ethoxylated stearyl alcohol with average 21EO and average 2 EO respectively.

Claims

1) A deodorant composition suitable for topical

application to the human skin, comprising an

effective amount of a synthetic spangolite analogue.

2) A deodorant composition suitable for application to human skin, comprising an effective amount of a layered hydroxide incorporating copper and other metal and having the structure of spangolite, in a physiologically acceptable carrier.

3) A deodorant composition according to claim 1 wherein the layered hydroxide has the general formula:

Cu_xZn_yTi (OH) ₁₂R₂ . nH₂O (II) wherein R is one or a mixture of divalent anions, especially sulphate or carbonate, the sum of x and y is 6, x and y being any number or fraction greater than 0 and smaller than 6, and n is any number varying from 1 to 6.

4) A deodorant composition according to claim 2, wherein the layered hydroxide material has the general formula:

(Zn+Cu)₆Ti(OH)₁₂(SO₄)₂.nH₂O (III) where n lies in the range from 1 to 6.

5) A deodorant composition according to claim 3 or claim 4 wherein the ratio Zn:Cu is in the region 1:1 - 3:1 6) A deodorant composition according to any one of

claims 1 to 5 wherein the composition contains from 0.05 to 20% by weight of the layered hydroxide. 7) A method of reducing human body odour comprising applying topically to human skin a composition as defined in any one of claims 1 to 6.