WO2025132032A1

WO2025132032A1 - Personal care composition

Info

Publication number: WO2025132032A1
Application number: PCT/EP2024/086066
Authority: WO
Inventors: Sameer Keshav Barne; Karthika BEENA; Maya Treesa Saji
Original assignee: Unilever Global IP Ltd; Unilever IP Holdings BV; Conopco Inc
Current assignee: Unilever Global IP Ltd; Unilever IP Holdings BV; Conopco Inc
Priority date: 2023-12-18
Filing date: 2024-12-12
Publication date: 2025-06-26
Anticipated expiration: 2026-06-18

Abstract

The invention relates to a personal care composition, more particularly to a composition for application to a topical surface, underarm surface or an oral surface of a human or animal that prevents or reduces malodour. The composition could be delivered in the form of a skin, care product. The present inventors have found that when a zinc and an activator combination is present in a personal care composition it provides for preventing and reducing the malodour for extended periods of time.

Description

PERSONAL CARE COMPOSITION

Field of the Invention

The invention relates to a personal care composition, more particularly to a composition for application to a topical surface to prevent or reduces malodour. The composition is preferably delivered in the form of a deodorant composition or an antiperspirant composition.

Background of the Invention

Personal hygiene is important for people and one of the negative indicators is body malodour.

In humans, the skin of underarm provides a unique niche for bacteria. Through the secretions of various glands that open onto skin, the environment is nutrient rich and hosts a unique microbial community. Human body odour contains several chemicals, but the most pungent and recognizable are thioalcohols. These molecules are created through a series of chemical reactions that start with an odourless precursor, a compound produced in glands located in the armpits. A type of bacteria called Staphylococcus hominis (S. hominis) is known to take in these molecules and metabolize them into thioalcohols which give the body the malodour.

Body malodour has been tackled in many ways. One approach is to use perfumes to mask the malodour, but this approach has benefit only for a limited time. Anti-perspirant compositions are also available to minimize the formation of sweat on the skin.

It is desired to provide composition that ensures sufficient malodour inhibition such that the surface smells fresh for a long time and develops minimal malodour thereafter.

Personal care compositions such as antiperspirant composition comprising metal halohydrate which are known for antiperspirant benefit, however they work indirectly by minimizing sweat formation thereby reducing the amount of nutrient available for the resident bacteria to metabolize and produce malodour causing molecules.

The principal disadvantage of many deodorant or antiperspirant active ingredients is that some of the commonly employed ingredients, such as the aforementioned aluminium or zirconium salts or bactericides and bacteriostatic agents, are perceived as being unfriendly to human skin, or to populations of micro-flora contained on human skin. Consequently, there is a desire in the industry to reduce or even eliminate the use of these materials. This is particularly the case with regard to their use in cosmetic products intended to be applied topically on human skin. Zinc salts such as zinc carboxylates represent a genus of deodorant active ingredients, generally recognized as safe, that act to exert a malodour-counteracting or eliminating effect by interacting or reacting chemically with malodorous ingredients, such as the myriad sulphur- or nitrogen- containing ingredients, or short-chain fatty acids, found in sweat. Zinc ricinoleate, zinc neodecanoate are some examples of a zinc carboxylate with deodorant applications.

EP 3538058 B1 (Givaudan, 2022) discloses a deodorant composition for controlling the human body odour by incorporating a deodorizing agent comprising zinc neodecanoate which is dissolved or mixed with fragrance component, and it was found that the addition of the deodorizing agent delivers a deodorancy benefit that is sustained, undistorted, and having a pleasant scent impression.

US2009/092568 A1 (Zorbx Inc, 2009) discloses an odor absorbing composition comprising zinc salt of ricinoleic acid and sodium iminodisuccinate.

However, zinc salts such as the zinc carboxylates, that interact chemically to absorb malodorous compounds are generally regarded to lack efficacy unless their incorporation levels in deodorant compositions are sufficiently high. In order to exert an acceptable odour- preventing/suppressing effect, these active ingredients need to be easily incorporated into the personal care composition bases, and preferably be readily soluble or miscible therein at efficacious levels. Furthermore, poor solubility of these material when administered to a site in need of treatment, can leave unsightly residues. Still further, when deodorant compositions are in aerosol format, un-dissolved material can cause nozzle clogging.

It is therefore an object of the present invention to provide for a personal care composition that prevent or hinders the formation of malodour.

It is another object of the present invention to provide for a composition that delivers malodour benefit without adversely affecting the resident microbiome on the topical surface.

Summary of the Invention

The present inventors have found that when a combination of specific zinc carboxylate salt and an activator is present in a personal care composition it provides for preventing and reducing the malodour for extended periods of time. According to a first aspect of the present invention there is provided a personal care composition comprising: i. a zinc carboxylate wherein the carboxylic acid comprises from 7 to 14 carbon atoms; ii. an activator selected from the group consisting of amino carboxylate, polyphosphate, wherein the polyphosphate has at least 6 phosphate repeating units, polyhydroxy carboxylate, ester of a carboxylic acid having an alkyl group with 2 to 12 carbon atoms and a mono alcohol with 2 to 8 carbon atoms and mixtures thereof; and, iii. a cosmetically acceptable base.

According to a second aspect of the present invention there is provided a non-therapeutic method of reducing or preventing malodour on a topical surface of a human or animal body comprising the step of applying the composition according to the first aspect of the invention on to the desired surface.

According to a third aspect of the invention provided is a non-therapeutic use of a composition according to the first aspect for reducing or preventing malodour on a topical surface of a human or animal body.

Detailed Description of the Invention

Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use may optionally be understood as modified by the word "about".

All amounts are by weight of the final composition, unless otherwise specified.

It should be noted that in specifying any ranges of values, any particular upper value can be associated with any particular lower value.

For the avoidance of doubt, the word "comprising" is intended to mean "including" but not necessarily "consisting of" or "composed of". In other words, the listed steps or options need not be exhaustive. The disclosure of the invention as found herein is to be considered to cover all embodiments as found in the claims as being multiply dependent upon each other irrespective of the fact that claims may be found without multiple dependency or redundancy.

Where a feature is disclosed with respect to a particular aspect of the invention (for example a composition of the invention), such disclosure is also to be considered to apply to any other aspect of the invention (for example a method of the invention) mutatis mutandis.

By a ‘topical composition’ or a ‘skin care composition’ as used herein, is meant to include a composition for topical application to the skin of mammals, especially humans. Such a composition could be of the leave-on or of the wash-off/ rinse-off type. By a leave-on composition is meant a composition that is applied to the desired skin surface and left on for a period of time (say from one minute to 24 hours) after which it may be wiped or rinsed off with water, usually during the regular course of personal washing. By a wash-off/ rinse off composition is meant a composition that is applied to the desired skin surface for a shorter period of time say of the order of seconds or minutes and usually contains sufficient surfactants that aids in cleaning the surface which may be rinsed off with copious amounts of water. The composition may also be formulated into a product which is applied to a human body for improving the appearance, cleansing, odor control or general aesthetics. The composition of the present invention can be in the form of a liquid, lotion, cream, foam, scrub, gel or stick form and may be delivered through a roll-on device or using a propellant containing aerosol can. "Skin" as used herein is meant to include skin on any part of the body e.g., neck, chest, back, arms, underarms, hands, legs, buttocks, and scalp. When the product is used for the underarms, it is usually called a deodorant product. A class of deodorant product is the so called anti-perspirant (AP) product which contains an AP active which when applied to the axilla of an individual delivers anti-perspirancy and deodorancy benefits.

Personal care composition

According to a first aspect, provided is a personal care composition comprising a zinc carboxylate salt, an activator, and a cosmetically acceptable base.

Zinc carboxylate salt

According to the first aspect, provided is a personal care composition comprising a zinc carboxylate salt wherein the carboxylic acid comprises from 7 to 14 carbon atoms. Preferably the zinc carboxylate salt is based on a carboxylic acid comprising from 9 to 14 carbon atoms. More preferably the zinc carboxylate salt is zinc neodecanoate.

Preferably the zinc carboxylate salt is a salt of zinc carboxylic acid with carboxylic acid comprising 7 to 14 carbon atoms. Preferably the carboxylic acid is a saturated carboxylic acid, an unsaturated carboxylic acid and combinations thereof.

Preferably the zinc carboxylate salt may be a zinc monocarboxylate, a zinc dicarboxylate, a zinc tricarboxylate or mixtures thereof. Preferably the zinc carboxylate salt is a zinc dicarboxylate, preferably a zinc dicarboxylate salt wherein at least one carboxylic acid comprises from 7 to 14 carbon atoms.

More preferably the zinc carboxylate is a zinc dicarboxylate, preferably a zinc neodecanoate which is a salt of zinc cation and neodecanoic acid having the formula [C₉H2o-CO.O]₂Zn.

Preferably the zinc dicarboxylate are salts of saturated fatty acids having from 7 to 14 carbon atoms. Preferably the zinc dicarboxylate are salts of saturated fatty acids having from 7 to 14 carbon atoms. More preferably the zinc dicarboxylate salt has branched chain fatty acid, particularly the branched chain fatty acids are saturated. Preferably the zinc dicarboxylate salt are salts of an alpha-branched fatty acid, that is a fatty caid having a branch, typically an alkyl branch, on the carbon atom adjacent to the carboxylic acid group (the “alpha-carbon”, designated as 2-IUPAC nomenclature). Such fatty acids are preferably having from 8 to 12 carbon atoms and are independently or in combination preferred to have three alkyl substituents at the alpha-carbon. Preferably the zinc dicarboxylate salt has from 8 to 14 carbon atoms, still preferably from 8 to 12 carbon atoms.

Preferably the levels of the zinc carboxylate salt, still preferably the levels of the zinc neodecanoate ranges from 0.05 wt.% to 5 wt.%, more preferably 0.1 wt.% to 2 wt.% by weight of the personal care composition.

Activator

By the term activator it is meant to include those compound which activate the function of the zinc carboxylate salt and enhances the efficacy of the composition in reducing the malodour on the skin and/or formation of the odour molecules on the skin resulting from the metabolic activity of microorganisms. Preferably due to the metabolic activity of skin bacteria, still preferably malodour causing bacteria, furthermore preferably Staphylococcus hominis.

An activator is an active that enhances the ability of the Zn carboxylate salt to suppress the metabolic activity of bacteria, preferably malodour causing bacteria, resulting in lowered odor molecule formation.

The reduction in the malodour is measuring using the Callus-Resazurin dye method. An active which lowers the fluorescence intensity measured using the Callus-Resazurin dye method when combined with zinc carboxylate salt qualifies as an activator in accordance with the present invention. Preferably the personal care composition having a zinc carboxylate salt and an activator in according to the present invention provides a fluorescence intensity of the dye when measuring using Callus-Resazurin dye method a reading of less than 50, still preferably less than 45. Preferably fluorescence reading ranges from 5 to 45, still preferably from 20 to 45. Preferably the personal care composition is a deodorant composition. Preferably the personal care composition is an antiperspirant composition comprising an antiperspirant active.

Without being bound by any theory it is believed that the combination of the zinc carboxylate salt and the specific activator according to the present invention enhances the anti-microbial efficacy of the zinc carboxylate salt. Preferably the combination of the zinc carboxylate salt and the specific activator according to the present invention enhances the anti-microbial efficacy of the zinc carboxylate salt, preferably where the bacteria is a malodour causing bacteria, still preferably a Staphylococcus hominis.

The Callus-Resazurin dye method measures the fluorescence intensity of the dye. Due to the metabolic activity of bacteria, nonfluorescent resazurin converts to strongly fluorescent resorufin resulting in formation of higher odor generating molecules.

According to the first aspect of the present invention, provided is an activator selected from the group consisting of amino carboxylate, polyphosphate wherein the polyphosphate comprises at least 6 repeating units, polyhydroxy carboxylate, an ester of a carboxylic acid having an alkyl group consisting of 2 to 12 carbon atoms and a mono-alcohol with 2 to 8 carbon atoms, and mixtures thereof. Preferably the levels of the activator, ranges from 0.1 wt.% to 5 wt.% by weight of the personal care composition. Preferably the personal care composition is a deodorant composition.

Preferably the personal care composition is an antiperspirant composition.

Amino carboxylate:

Preferably the activator is an amino carboxylate which is preferably selected from the group consisting of methyl glycine diacetate trisodium salt (trisodium a-DL-alanine diacetate), glutamate diacetate trisodium (GLDA) and mixtures thereof. Preferably the amino carboxylate activator has an amino group with a secondary N or a tertiary nitrogen.

The activator may be chosen preferably from amino carboxylic acids (i.e. acids comprising at least one carboxylic acid group) such as the compounds having the following INCI name: phytic acid, diethylenetriaminepentaacetic acid (DTPA), ethylene diamine disuccinic acid (EDDS) and trisodium ethylenediamine di-succinate such as Octaquest E30 from Octel, ethylenediaminetetraacetic acid (EDTA), ethylenediamine-N, N' -diglutaric acid (EDDG), glycinamide-N,N' -disuccinic acid (GADS), 2-hydroxypropylenediamine-N, N' -disuccinic acid (HPDDS), ethylenediamine-N, N' -bis (ortho-hydroxyphenylacetic acid) (EDDHA),

N, N' -bis (2-hydroxybenzyl) ethylenediamine-N, N' - diacetic acid (HBED), nitrilotriacetic acid (NTA), methylglycine diacetic acid (MGDA), N-2-hydroxyethyl-N, N-diacetic acid and glyceryl imino diacetic acid (as described in documents EP- A-317 542 and EP-A-399 133), iminodiacetic acid-N-2-hydroxypropyl sulfonic acid and aspartic acid N-carboxymethyl N-2- hydroxypropyl -3 -sulfonic acid (as described in EP- A-516 102), beta-alanine-N, N' -diacetic acid, aspartic acid- N, N' -diacetic acid and aspartic acid-N-monoacetic acid (described in EP-A- 509 382), chelating agents based on iminodisuccinic acid (IDSA) (as described in EP-A-509 382), ethanoldiglycine acid, phosphonobutane tricarboxylic acid, such as the compound sold by Bayer under the reference Bayhibit AM, tetrasodium glutamate diacetate (GLDA) such as Dissolvine GL38 or 45S from Akzo Nobel.

Preferably the levels of the amino carboxylate activator, more preferably the levels of the GLDA ranges from 0.1 wt.% to 5 wt.% by weight of the personal care composition. Preferably the personal care composition is a deodorant composition. Preferably the personal care composition is an antiperspirant composition.

Polyphosphate: Preferably the activator is a polyphosphate activator wherein the polyphosphate has at least 6 phosphate repeating units. More preferably the polyphosphate activator is hexametaphosphate.

Preferably the levels of the polyphosphate activator, ranges from 0.1 wt.% to 5 wt.% by weight of the personal care composition.

Polyhydroxy carboxylate:

Preferably the activator is a polyhydroxy carboxylate. Preferably the polyhydroxy carboxylate activator is gluconic acid or salts thereof. More preferably the polyhydroxy carboxylate is an alkali metal salt of gluconate, preferably sodium gluconate.

Preferably the levels of the polyhydroxy carboxylate, ranges from 0.1 wt.% to 5 wt.% by weight of the personal care composition.

Ester based activator:

Preferably the activator is an ester of a carboxylic acid with an alkyl group having 2 to 12 carbon atoms and a mono alcohol with 2 to 8 carbon atoms. More preferably the ester based activator according to the present invention is triethyl citrate, tributyl citrate and mixtures thereof.

Preferably the levels of the ester-based activator, ranges from 0.1 wt.% to 5 wt.% by weight of the personal care composition.

Cosmetically acceptable base

According to the first aspect of the present invention the personal care composition includes a cosmetically acceptable base. Preferably the cosmetically acceptable base may be those used in personal care composition. Preferably the cosmetically acceptable base is a topically acceptable base, when the personal care composition is a deodorant composition or an antiperspirant composition. Preferably the cosmetically acceptable base comprises water, oil, surfactant, abrasive cleanser, emulsion, gel, or combinations thereof.

Deodorant composition

Preferably the personal care composition is a deodorant composition.

The composition of the invention could be delivered as a personal care deodorant composition delivered in a soft solid/ stick form, as a roll on or through a propellant containing composition for giving malodour benefits. The personal care product is preferably applied on the skin especially the underarm region. The personal care composition preferably comprises a topically acceptable carrier which in the present invention is anhydrous. To enable this, the anhydrous carrier preferably comprises a silicone compound, an alcohol, or a wax. The alcohol, when used, could be a low boiling (C₂-C₄) alcohol or a polyhydric alcohol, preferably a polyhydric alcohol. The composition of the invention preferably comprises a polyhydric alcohol. Polyhydric alcohol is also referred to in short as polyol. A polyhydric alcohol as per the present invention is a compound having two or more hydroxyl groups. Suitable class of polyhydric alcohols that may be included in the composition of the invention are monomeric polyols, polyalkylene glycols or sugars. Preferred monomeric polyols are glycol; alkylene glycol e.g., propylene glycol, glycerol; or xylitol, more preferably propylene glycol. Suitable polyalkylene glycols are polyethylene glycol or polypropylene glycol. Sugars for inclusion in the invention could be monomeric, dimeric, trimeric or of the polymeric form. Preferred sugars include glucose, fructose, mannose, sucrose, threitol, erythritol, sorbitol, mannitol, galactitol, adonitol, dextran, or cyclodextrin. Of these the more preferred sugars are glucose, fructose, sucrose, sorbitol, mannitol, adonitol, dextran, or cyclodextrin.

Preferably when the personal care composition according to the first aspect of the present invention is an antiperspirant composition, the zinc compound is preferably selected from zinc carboxylate, zinc citrate and mixtures thereof. Most preferably the zinc carboxylate is zinc neodecanoate.

Other components commonly included in conventional personal care compositions may also be incorporated in the composition of the present invention. Such components include skin care agents such as emollients, humectants, and skin barrier promoters; skin appearance modifiers such as skin lightening agents and skin smoothing agents; anti-microbial agents, in particular organic anti-microbial agents, and preservatives.

The personal care composition can be applied cosmetically and topically to the skin, broadly speaking, by one of two methods. Some consumers prefer one method and some others, the other method. In one method, sometimes called a contact method, a composition is wiped across the surface of the skin, depositing a fraction of the composition as it passes. In the second method, sometimes called the non-contact method, the composition is sprayed from a dispenser held proximate to the skin, often in an area of about 10 to 20 cm². The spray can be developed by mechanical means of generating pressure on the contents of the dispenser, such as a pump or a squeezable sidewall or by internally generated pressure arising from a fraction of a liquefied propellant volatilizing, the dispenser commonly being called an aerosol. There are broadly speaking two classes of contact compositions, one of which is liquid and usually applied using a roll-on dispenser or possibly absorbed into or onto a wipe, and in the second of which the active is distributed within a carrier liquid that forms a continuous phase that has been gelled. In one variation, the carrier fluid comprises a solvent for the composition and in a second variation, the actives remain in a particulate solid that is suspended in an oil, usually a blend of oils.

Stick or soft solid composition

Many different materials have been proposed as gellant for a continuous oil phase, including waxes, small molecule gelling agents and polymers. They each have their advantages and of them, one of the most popular class of gellant has comprised waxes, partly at least due to their ready availability and ease of processing, including in particular linear fatty alcohol wax gellants. A gelled composition is applied topically to skin by wiping it across and in contact with the skin, thereby depositing on the skin a thin film.

The nature of the film depends to a significant extent on the gellant that is employed. Although wax fatty alcohols have been employed as gellant for many years, and are effective for the purpose of gelling, the resultant product is rather ineffective at improving the visual appearance of skin, and in particular underarm skin, to which the composition has been applied. This problem has been solved by including ameliorating materials for example, di or polyhydric humectants and/or a triglyceride oil.

Roll-on

Liquid compositions that are applicable from a roll-on broadly speaking can be divided into two classes, namely those in which an active is suspended in a hydrophobic carrier, such as a volatile silicone and those in which the actives are dissolved in a carrier liquid. The latter has proven to be more popular. There are mainly two sorts of dissolving carrier liquid, namely carriers that are predominantly alcoholic, which is to say the greater part of the dissolving carrier fluid comprises ethanol and the second class in which the carrier liquid is mainly water. Since the present invention involves a hydrophobic composition, the former is used. The former is very popular because ethanol is a mild bactericide in its own right.

Aerosol compositions The personal care composition may be delivered through an aerosol composition which comprises a propellant in addition to the other ingredients described hereinabove. Commonly, the propellant is employed in a weight ratio to the base formulation of from 95:5 to 5:95. Depending on the propellant, in such aerosol compositions the ratio of propellant to base formulation is normally at least 20:80, generally at least 30:70, particularly at least 40:60, and in many formulations, the weight ratio is from 90:10 to 50:50. A ratio range of from 70:30 to 90:10 is sometimes preferred. Propellants herein generally are one of three classes; i) low boiling point gasses liquifided by compression, ii) volatile ethers and iii) compressed non-oxidising gases.

Class i) is conveniently a low boiling point material, typically boiling below -5°C, and often below — 15°C, and in particular, alkanes and/or halogenated hydrocarbons. This class of propellant is usually liquefied at the pressure in the aerosol canister and evaporates to generate the pressure to expel the composition out of the canister. Examples of suitable alkanes include particularly propane, butane, or isobutane. The second class of propellant comprises a very volatile ether of which the most widely employed ether hitherto is dimethyl ether. This propellant can advantageously be employed at relatively low weight ratio of propellant to base formulation, for example to as low as 5:95. It can also be employed in admixture with, for example, compressible/liquefiable alkane gasses. The third class of propellant comprises compressed non-oxidising gasses, and in particular carbon dioxide or nitrogen. Inert gases like neon are a theoretical alternative.

The composition of the present invention can comprise a wide range of other optional 5 components. The CTFA Personal care Ingredient Handbook, Second Edition, 1992, which is incorporated by reference herein in its entirety, describes a wide variety of non-limiting personal care and pharmaceutical ingredients commonly used in the skin care industry, which are suitable for use in the compositions of the present invention. Examples include: binders, biological additives, buffering agents, colorants, thickeners, polymers, astringents, fragrance, conditioners, exfoliating agents, pH adjusters, preservatives, natural extracts, essential oils, skin sensates, skin soothing agents, and skin healing agents.

Antiperspirant composition

Preferably the personal care composition is an antiperspirant composition. By “An Antiperspirant Composition” as used herein, is meant to include a composition for topical application to the skin of mammals, especially humans. Such a composition is preferably of the leave-on type. By a leave-on composition is meant a composition that is applied to the desired skin surface and left on for a period of time (say from one minute to 24 hours) after which it may be wiped or rinsed off with water, usually during the regular course of personal washing. The composition may also be formulated into a product which is applied to a human body for improving the appearance, cleansing, odor control or general aesthetics. “Skin” as used herein is meant to include skin on any part of the body (e.g., neck, chest, back, arms, underarms, hands, legs, buttocks, and scalp) especially the underarms. Alternatively, they may be delivered through a roll-on device or by using a propellant containing aerosol can. Preferably the anhydrous composition is a solid anhydrous composition in the form of a stick suitable for delivery through a roll-on device. It is especially useful for delivering low pH compositions to the axilla of an individual for anti-perspirancy benefits. “Skin” as used herein is meant to include skin on any part of the body (e.g., neck, chest, back, arms, underarms, hands, legs, buttocks, and scalp) especially the underarms.

Antiperspirant active

Preferably the antiperspirant active is a metal based antiperspirant active or a non-metal based antiperspirant active.

The anti-perspirant composition according to this invention preferably includes a metal based antiperspirant active. This may be selected from an aluminium, zirconium, or mixed aluminium/zirconium salts, preferably, aluminium ch loro hydrate, aluminum-zirconium tetrachlorohydrex glycine complex, aluminum-zirconium octachlorohydrex glycine complex, aluminum-zirconium pentachlorohydrate, aluminum sesquichlorohydrate (ASCH) or mixtures thereof.

Antiperspirant actives for use herein are selected from aluminium, zirconium, and mixed aluminium/zirconium salts, including both inorganic salts, salts with organic anions and complexes. Particularly preferred astringent salts are halohydrate salts, and especially chlorohydrate salts, optionally activated. For aerosol compositions, the antiperspirant active is preferably free from zirconium.

Aluminium halohydrates are usually defined by the general formula AI₂(OH)_xQ_y.wH₂O in which Q represents a halogen selected from the group consisting of chlorine, bromine iodine or mixtures thereof, x is variable from 2 to 5 and x + y = 6 while wH20 represents a variable amount of hydration. Especially effective aluminium halohydrate salts, known as activated aluminium chlorohydrates, are described in EP-A-6739 (Unilever NV et al), the contents of which specification is incorporated herein by reference.

The term aluminium chlorohydrate herein encompasses materials with specified figures for x and y, such as aluminium sesquichlorohydrate and materials in which the chlorohydrate is present as a complex. It will be recognized that alternative names are sometimes used to indicate the presence of hydroxyl substitution, including aluminium hydroxy chloride, aluminium oxychloride, or basic aluminium chloride.

Zirconium astringent salts for employment herein as the metal based antiperspirant active can usually be represented by the empirical general formula: ZrO(OH)_2n-nzB_z.wH2O in which z is a variable in the range of from 0.9 to 2.0 so that the value 2_n-nz is zero or positive, n is the valency of B, and B is selected from the group consisting of chloride, other halide, sulphamate, sulphate or mixtures thereof. Possible hydration to a variable extent is represented by wH₂0.

Preferably, B represents chloride. Preferably, the variable z lies in the range from 1 .5 to 1 .87. In practice, such zirconium salts are commonly not employed by themselves, but as a component of a combined aluminium and zirconium-based antiperspirant active.

The above aluminium and zirconium salts may have coordinated and/or bound water in various quantities and/or may be present as polymeric species, mixtures, or complexes. In particular, zirconium hydroxy salts often represent a range of salts having various amounts of the hydroxy group. Zirconium aluminium chlorohydrate may be particularly preferred.

Antiperspirant complexes based on the above-mentioned astringent aluminium and/or zirconium salts can be employed as metal based antiperspirant active. The complex often employs a compound with a carboxylate group, and advantageously this is an amino acid. Examples of suitable amino acids include dl-tryptophan, dl-p-phenylalanine, dl-valine, dl- methionine, and p-alanine, and preferably glycine which has the formula CH₂(NH₂)COOH. Certain of those Al/Zr complexes are commonly called ZAG in the literature. ZAG actives generally contain aluminium, zirconium, and chloride with an Al/Zr ratio in a range from 2 to 10, especially 2 to 6, an AI/CI ratio from 2.1 to 0.9 and a variable amount of glycine. Actives of this preferred type are available from Westwood, from Summit and from Reheis. Alternatively, the complex can be pre-formed with a polyhydric aliphatic alcohol, such as propylene glycol or glycerol. A complex with a chlorohydrate is commonly referred to as a chlorhydrex.

Mixtures of two or more astringent salts can be employed, but, however, it is particularly preferred to employ astringent salts that are free from zirconium, such as aluminium chlorohydrates and so-called activated aluminium chlorohydrates.

According to an especially preferred aspect of the present invention the metal based antiperspirant active is aluminium chlorohydrate, aluminum sesquichlorohydrate or mixtures thereof.

The metal based antiperspirant active preferably is included in an amount ranging from 1 wt.% to 50 wt.%, more preferably 2 wt.% to 25 wt.%, most preferably 2 wt.% to 15 wt.% by weight of the composition.

The metal based antiperspirant active is more preferably present in an amount ranging from 2 wt.% to 30 wt.% in the antiperspirant composition. Preferably the antiperspirant composition comprises at least 3 wt.%, still preferably at least 5 wt.%, still preferably at least 6 wt.%, most preferably at least 10 wt.% of the metal based antiperspirant active, but typically not more than 25 wt.%, still preferably not more than 20 wt.%, still further preferably not more than 18 wt.%, still more preferably not more than 16 wt.% and most preferably not more than 15 wt.%, of a metal based antiperspirant active based on the weight of the antiperspirant composition.

More particularly antiperspirant composition includes antiperspirant active in an amount ranging from 26 wt.% to 50 wt.%.

Preferably concentrated aerosol antiperspirant composition including high levels of antiperspirant active ranging from 8 wt.% to 25 wt, still more preferably from 10 wt.% to 20 wt.%. Preferably the concentrated aerosol antiperspirant composition includes from 50 to 75 wt.% propellant gas and from 8 wt.% 25 wt.%, still preferably from 10 wt.% to 22 wt.% carrier oil.

The anti-perspirant composition according to this invention preferably includes a non-metal based antiperspirant active. Preferably the non-metal based antiperspirant active is selected from sorbiton esters, long chain fatty acids, lecithin, amino acid derivatives, natural gums, and polysaccharides.

Preferably the antiperspirant composition may optionally include an unsaturated oil. The antiperspirant composition according to the first aspect of the present invention includes an unsaturated oil having an iodine value of at least 70, preferably at least 80, still preferably at least 90, and also more preferably at least 100.

Preferably the antiperspirant composition may optionally contain additives customary in cosmetics, for example, perfume, thickeners, deodorants, antimicrobial substances, regreasing agents, complexing and masking agents, pearlescent agents, plant extracts, vitamins, active ingredients, preservatives, bactericides, dyes, pigments that have a coloring effect, thickeners, moisturizing and/or humectant substances, fats, oils, waxes or other usual constituents of a cosmetic or dermatological formulation, such as alcohols, polyols, polymers, foam stabilizers, electrolytes, organic solvents or silicone derivatives, unless they are counter to the composition according to the invention and the use thereof.

Preferably the deodorant composition according to the present invention comprises: i. a zinc carboxylate salt wherein the carboxylic acid comprises from 7 to 14 carbon atoms; ii. an activator selected from the group consisting of amino carboxylate, polyphosphate wherein the polyphosphate activator has at least 6 phosphate repeating groups, polyhydroxy carboxylate, an ester of carboxylic acid having an alkyl group with 2 to 12 carbon atoms and a monoalcohol with alkyl group having 1 to 8 carbon atoms and mixtures thereof; and, iii. a cosmetically acceptable base.

Preferably the deodorant composition according to the present invention comprises:

(i) a zinc carboxylate salt wherein the carboxylic acid comprises from 7 to 14 carbon atoms;

(ii) an activator selected from the group consisting of amino carboxylate, polyphosphate wherein the polyphosphate activator has at least 6 phosphate repeating groups, polyhydroxy carboxylate, less than 5 wt.% an ester of carboxylic acid having an alkyl group with 2 to 12 carbon atoms and a monoalcohol with alkyl group having 1 to 8 carbon atoms and mixtures thereof; and,

(iii) a cosmetically acceptable base.

(ii) an activator selected from the group consisting of amino carboxylate, polyphosphate wherein the polyphosphate activator has at least 6 phosphate repeating groups, polyhydroxy carboxylate, and mixtures thereof; and,

(iii) a cosmetically acceptable base.

Preferably the deodorant composition includes an antiperspirant active.

According to a second aspect of the present invention provided is a non-therapeutic method of reducing or preventing malodour on a topical surface of a human or animal body comprising the step of applying the personal care composition according to the first aspect on to the desired surface. Preferably the personal care composition is a deodorant composition. Preferably the personal care composition is an antiperspirant composition. Preferably the antiperspirant composition comprises an antiperspirant active.

According to a third aspect of the present invention provided is a non-therapeutic use of a composition according to the first aspect for reducing or preventing malodour on a topical surface of a human or animal body. Preferably the personal care composition is a deodorant composition. Preferably the personal care composition is an antiperspirant composition. Preferably the antiperspirant composition comprises an antiperspirant active.

Callus plates were prepared with 1% agarose in a multi well plate layered with callus. The test organism S. hominis ATCC 27844 was grown on TSA (Tryptic Soya Agar) plates overnight (22 ± 2 hr). The organism was not more than 3 passages removed from the original source. The cell number was adjusted by re-suspending it in a suitable amount of physiological saline sufficient to achieve the required cell number based on optical density of the cells using a spectrophotometer. The optical density (at 620) of the cells were standardized to the cell number of 10⁷ in saline and added to the callus plate and dried it for 1 hr.

Various samples as shown in table 1 below were prepared at the required concentration and each sample was added to the callus wells according to the final dosage. The final dosage was calculated for 3 mg/cm² for the treatment. After the treatment the plates were kept under laminar air flow to dry. Resazurin dye was prepared at 0.1% in sterile water and was added into the treated well plate and allowed it to dry. The plates were incubated at 370°C and after 24 h a fluorescent reading was taken at excitation wavelength of 550 nm and emission wavelength 600 nm using a TECAN plate reader. A lower fluorescence reading indicates a lower growth and metabolic activity of the malodour causing bacteria which in turn indicates a higher efficacy of the actives.

Example 1 : Effect of various zinc carboxylate salt, activator and combinations thereof on the malodour.

Different samples having different activator, zinc carboxylate salt, or their combination were tested using the protocol as mentioned hereinabove and the fluorescent reading obtained has been provided in table 1 below.

Table 1

Control is normalized to 100.

The data on table 1 shows that that the samples having only zinc carboxylate salt (Ex A) or only the activator (Ex B, Ex C, Ex D and Ex E) have a higher fluorescence reading as compared to the samples according to the present invention having a combination of zinc carboxylate salt and the activator. A lower fluorescence reading indicates higher efficacy of the combination of zinc carboxylate salt and the activator against malodour causing bacteria which provides higher malodour reduction. The data indicates that specific carboxylate salt having a carboxylic acid with 7 to 14 carbon atoms in combination with specific activator according to the present invention provides improved efficacy towards malodour reduction.

Claims

1 . A personal care composition comprising: i. zinc carboxylate salt wherein the carboxylic acid comprises from 7 to 14 carbon atoms, , ; ii. an activator selected from the group consisting of amino carboxylate, polyphosphate wherein the polyphosphate activator has at least 6 phosphate repeating groups, polyhydroxy carboxylate, an ester of a carboxylic acid having an alkyl group with 2 to 12 carbon atoms and a monoalcohol with alkyl group having 1 to 8 carbon atoms, and mixtures thereof; and, iii. a cosmetically acceptable base.

2. A composition comprising according to claim 1 wherein the zinc carboxylate salt is a zinc dicarboxylate, preferably a zinc dicarboxylate salt wherein at least one carboxylic acid comprises from 7 to 14 carbon atoms.

3. A composition according to claim 1 or 2 wherein the amino carboxylate activator is selected from the group consisting of methyl glycine diacetate trisodium salt (trisodium a-DL-alanine diacetate), glutamate diacetate trisodium (GLDA) and mixtures thereof.

4. A composition according to any one of the preceding claims wherein the polyphosphate activator is hexametaphosphate.

5. A composition according to any one of the preceding claims wherein the polyhydroxy carboxylate activator is a gluonic acid or a salt thereof, preferably an alkali metal salt of gluconate, still preferably sodium gluconate.

6. A composition according to any one of the preceding claims wherein ester activator is triethyl citrate, tributyl citrate and mixtures thereof.

7. A composition as claimed in any one of the preceding claims 1 to 6 wherein the cosmetically acceptable base comprises water, oil, surfactant, abrasive cleanser, emulsion, gel, or combinations thereof.

8. A composition according to any one of the preceding claims wherein the personal care composition is a deodorant composition or an antiperspirant composition.

9. A composition according to any one of the preceding claims wherein the amount of the zinc carboxylate salt ranges from 0.05 wt.% to 5 wt.%.

10. A composition according to any one of the preceding claims wherein the amount of the activator ranges from 0.1 wt.% to 5 wt.%.

11. A non-therapeutic method of reducing or preventing malodour on a topical surface of a human or animal body comprising the step of applying the composition as claimed in any one of the preceding claims 1 to 11 on to the desired surface.

12. Non-therapeutic use of a composition as claimed in any one of the preceding claims 1 to 10 for reducing or preventing malodour on a topical surface of a human or animal body.