Field of the invention

The present invention relates to an antimicrobial composition and a method for disinfection involving the antimicrobial composition. It particularly relates to an antimicrobial composition for personal cleaning, oral care or hard surface cleaning applications.

Background of the invention

Sanitising and disinfecting soap or cleaning compositions are of great benefit to individuals, since proper use generally may reduce the number of germs and pathogens the individual is exposed to. Thus, such compositions may for instance play an important role in reducing the occurrence and spread of infectious diseases. Sanitising and disinfecting soap compositions comprising chlorine-based antimicrobial agents such as triclosan are known. Such compositions require a rather long contact time to provide efficacious antimicrobial action. In practice, users, in particular children, do not spend a long time on cleaning and as a result cleaning with such compositions does not provide adequate prevention from surface or topical infection or adequate protection against diseases. The user, in spite of cleaning his hands, is generally likely to end up with relatively inadequate bacterial removal from his skin. Therefore, he may cause contamination of further animate and/or inanimate surfaces and contribute to the spreading of pathogens and consequent diseases. Users in general and children in particular who wash contaminated hands before meals with slow-acting antimicrobial compositions for a relatively short time are at risk of contracting diseases.

Similarly, in the area of hard surface cleaning, e.g. cleaning of floors, table tops or utensils, the antimicrobial actives in the compositions are in contact with the substrate for less than a few minutes, after which the surface is either wiped off or rinsed with water. These short time scales of cleaning action are ineffective in providing the desired benefit since most known antimicrobials commonly used in such products take many minutes to hours to provide the desired kill of microbes. Therefore, there is a need for providing a composition that -upon application- provides relatively more efficacious antimicrobial action during a relatively short cleaning period, preferably about 30 seconds or less, more preferably 15 seconds or less. A well-established class of antimicrobially active compounds are phenolic compounds [P. A. Goddard and K. A. McCue in "Disinfection, Sterilisation and Preservation", ed. S. S. Block, 5th edition, Lippincott, Williams and Wilkins, Philadelphia, 2001, pp. 255-282.]. However, not every phenolic compound is suitable as an antimicrobial agent.

Moreover, many surfactants, although anti-microbially active may exhibit undesirable side effects, such as corrosion, malodour and skin irritation or skin-sensitising effects when applied on human or animal skin.

A particular problem of thymol is that it has a potent odour which is odour typically held to be too intense by consumers at concentrations at which thymol is efficacious as a disinfectant.

Additionally, a lower concentration of odoriferous compounds including thymol or the availability of antimicrobial compounds that are less or not odoriferous allows greater flexibility to the manufacturer in providing alternative scents to his composition at lower doses. Hence, there is a need for antimicrobial compositions and methods that require lower concentrations of thymol and/or have a more acceptable sensory profile.

In addition, there is a continued need to reduce the total amount of active ingredients required in such an antimicrobial composition. This need may for instance be driven by the desire for cost-efficiency, because such compositions are particularly relevant to developing countries. Moreover, reducing the amounts may also be beneficial for environmental reasons. In view of the above-observed problems and drawbacks of the prior art, it is an object of the present invention to provide alternative antimicrobial compositions.

It is a particular object of the invention to provide such compositions, requiring a lower dose of antimicrobial compounds.

Similarly, it is an object of the present invention to provide an antimicrobial composition in which the olfactory contribution of the antimicrobially active compounds is reduced or in which the active compound contributes to providing a consumer-acceptable or even consumer-appreciated scent.

It is another particular object of the invention to provide an antimicrobial composition that contributes to reducing the required contact time in a method for disinfection of a surface. In particular, it is an object of the invention to provide an antimicrobial composition which gives improved disinfection during cleaning of surfaces of the human body, such as the skin and the oral cavity.

It is yet another object of the present invention to provide an alternative method for sanitising and/or disinfecting, in particular of surfaces.

It is a further object of the invention to provide a method for disinfection with a reduced disinfection time. More specifically, it is an object of the invention to provide a method, wherein the disinfection time of the method is less than 300 seconds, preferably less than 120 seconds, more preferably less than 60 seconds, and even more preferably less than 30 seconds.

In particular, it is an object of the invention to provide a method for disinfection that gives improved disinfection during cleaning of surfaces, in particular hard surfaces, or surfaces of the human body, such as the skin and the oral cavity.

SUMMARY OF THE INVENTION

We have now found that one or more of the above objects are met by the present invention. It has been surprisingly found that the above objects are met by the presently claimed composition. Compositions have been found that provide efficacious antimicrobial action at lower concentrations when compared to cationic surfactant alone. In addition, it has been found complete microbial inactivation could be effected with compositions as defined herein after a contact time of less than 5 minutes, preferably 2 minutes, more preferably less than 1 minute and most preferably less than 30 seconds.

By virtue of the enhanced antimicrobial efficacy of cationic surfactants with a combination of substituted phenol, aliphatic terpene alcohol and unsaturated terpenes, the composition contributes to a reduction in olfactory disadvantages associated with the presence of large amounts of thymol.

Accordingly, in a first aspect, there is provided an antimicrobial composition comprising: a) a cationic surfactant, b) one or more substituted phenols selected from the group comprising thymol, sec- butylphenol, carvacrol, eugenol, propylphenol and mixtures thereof, c) one or more aliphatic terpene alcohols selected from menthol, isomenthol, neomenthol, neoisomenthol and mixtures thereof; and d) one or more unsaturated terpenes selected from the group comprising limonene, alpha-terpinene, terpinolene, cymene, phellandrene or mixtures thereof, preferably limonene, wherein the substituted phenol, the aliphatic terpene alcohol and the unsaturated terpene are present in the ratio 1:0.5:0.5.

For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. The word "comprising" is intended to mean "including" but not necessarily "consisting of” or "composed of". Thus, the term "comprising" is meant not to be limiting to any subsequently stated elements, but rather to optionally also encompass non-specified elements of major or minor functional importance. In other words, the listed steps or options need not be exhaustive. Whenever the words "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined above. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. 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 are to be understood as modified by the word "about". Unless specified otherwise, numerical ranges expressed in the format "x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "x to y", it is understood that all ranges combining the different endpoints are also contemplated. Unless specified otherwise, amounts as used herein are expressed in percentage by weight based on total weight of the composition and is abbreviated as “wt%”.

Throughout this description, the term disinfection refers to reduction of the number of viable microorganisms in a given medium or on a given surface by physical or chemical means. Typically, disinfection involves the destruction or inactivation of said microorganisms. Both animate and inanimate media and surfaces are contemplated. The term "microbicide" refers to a compound capable of killing, inhibiting the growth of or controlling the growth of microorganisms at a locus; microbicides include bactericides, fungicides and algaecides. The term "microorganism" includes, for example, fungi (such as yeast and mould), bacteria and algae.

The compositions of the present invention are preferred for non-therapeutic use, and more particularly preferred for use in cleaning surfaces, preferably wherein the surface is a hard surface and more preferably for use in cleaning applications such as cleaning kitchen, bathroom and floor surfaces.

The composition comprises a cationic surfactant. Preferably, the cationic surfactant is a quaternary ammonium surfactant, preferably the quaternary ammonium surfactant is selected from cetyl trimethyl ammonium chloride (CTAC), didecyl dimethyl ammonium chloride (DDAC), alkyl dimethyl benzyl ammonium chloride (ADBAC) and mixtures thereof. More preferably the cationic surfactant is alkyl dimethyl benzylammonium chloride e.g. benzalkonium chloride (BKC).

Preferably, the composition comprises 0.01 to 20 wt%, more preferably 0.05 to 15 wt%, most preferably 0.1 to 10 wt% cationic surfactant.

The composition comprises one or more substituted phenols selected from thymol, sec- butylphenol, carvacrol, eugenol, propylphenol and mixtures thereof.

The amount of the one or more substituted phenols selected from thymol, sec-butylphenol, carvacrol, eugenol, propylphenol and mixtures thereof is preferably in the range of 0.01 to 5 wt%, more preferably 0.02 to 2.5 wt%, even more preferably 0.05 to 2 wt%, further more preferably 0.075 to 1.5 %, yet more preferably 0.1 to 1.0 % and most preferably 0.5 to 1.0%.

Preferably the substituted phenol is butyl phenol or thymol, more preferably thymol. The structural isomer of thymol (carvacrol) may also preferably be used.

The composition preferably comprises 0.01 to 5 wt%, more preferably 0.02 to 2.5 wt%, even more preferably 0.05 to 2 wt%, further more preferably 0.075 to 1.5 wt%, yet more preferably 0.1 to 1.0 wt% and most preferably 0.5 to 1.0 wt% of thymol.

The composition comprises one or more aliphatic terpene alcohols. The terpene alcohol is preferably present in the composition in the range 0.01 to 5 wt%, more preferably 0.02 to 2.5 wt%, even more preferably 0.025 to 1.0 wt%, yet more preferably 0.05 to 0.75 wt% and even more preferably 0.1 to 0.5 wt% of terpene alcohol.

The aliphatic terpene alcohol is preferably selected from menthol, isomenthol, neomenthol, neoisomenthol and mixtures thereof. The terpene alcohol may be the (+) or (-) stereoisomers, for example (+)-menthol, (+)-isomenthol, (+)-neomenthol, (+)-neoisomenthol, (-)-menthol, (-)-isomenthol, (-)-neomenthol, (-)-neoisomenthol.

The structure of (-)-menthol is given below: Within the meaning of the present application “aliphatic terpene” preferably means that the terpene does not contain unsaturated (carbon-carbon) bonds. Preferably, the aliphatic terpene is a saturated aliphatic terpene.

The composition of the present invention also comprises one or more unsaturated terpenes. The amount of one or more unsaturated terpenes preferably is in the range 0.01 to 5 wt%, more preferably 0.02 to 2.5 wt%, even more preferably 0.025 to 1.0 wt%, yet more preferably 0.05 to 0.75 wt% and even more preferably 0.1 to 0.5 wt%.

Preferably, the one or more unsaturated terpenes comprises limonene, alpha-terpinene, terpinolene, cymene, phellandrene or mixtures thereof, preferably limonene.

Wthin the meaning of the present application, “unsaturated terpene” preferably means that the terpene contains at least one unsaturated (carbon-carbon) bond and does not contain a hydroxyl moiety.

Preferably, the unsaturated terpene is limonene. The structure of limonene is given below:

The substituted phenol, the aliphatic terpene alcohol and the unsaturated terpene are present in the ratio 1:0.5:0.5.

It will be understood that the substituted phenol is present in 1 part, then the aliphatic terpene alcohol is present in 0.5 part; and the unsaturated terpene is present in 0.5 parts. For example, if a substituted phenol e. g. thymol or eugenol or butyl phenol, is present in 1 part, then an aliphatic terpene alcohol e. g. menthol, is present in 0.5 part; and an unsaturated terpene e. g. limonene or terpinolene or alpha-terpinene, is present in 0.5 part.

Preferably, the composition comprises thymol, menthol, and limonene. Preferably, the composition comprises 0.05 to 2 wt% thymol, 0.025 to 1 wt% menthol, 0.25 to 2 wt% limonene.

The composition preferably comprises 0.1 to 10 wt%, more preferably 1 to 9 wt%, even more preferably 2 to 8 wt% and most preferably 3 to 7 wt%, of the substituted phenols, aliphatic terpene alcohols, unsaturated terpenes and mixtures thereof.

In compositions intended to be diluted before application, the minimum preferred concentrations of the one or more substituted phenol, aliphatic terpene alcohol and unsaturated terpene can be higher. For example, when washing hands with water and a composition according to the invention, the lather produced, is typically a 50 wt% dilution of the original composition. Similarly, in body wash situations, soap bars or soap liquids are typically diluted until about 8 wt% soap in water, corresponding to an approximately tenfold dilution of the product. Therefore, compositions according to the invention intended for dilution upon use preferably comprise 0.05 to 4.5 wt%, more preferably 0.1 to 4 wt% even more preferably 0.2 to 3 wt% still more preferably 0.4 to 1 wt% and still more preferably 0.5 to 1 wt% of the components. Thus, the concentration of the one or more components in the antimicrobial composition is preferably such that, when the composition is diluted or dissolved with a suitable medium during use, the concentration in the diluted or dissolved mixture is still sufficient to be anti-microbially efficacious.

Any of the concentrations ranges for the substituted phenol is preferably combined with any of the concentration ranges for the one or more aliphatic terpene alcohols and unsaturated terpine specified above. For example, the antimicrobial composition according to the invention preferably comprise: b) 0.05 to 2 wt% thymol, c) 0.025 to 1 wt%, one or more aliphatic terpene alcohols; and d) 0.025 to 1 wt% one or more unsaturated terpenes. Preferably, the composition comprises 0.1 to 80 wt %, more preferably 0.5 to 50 wt%, even more preferably 1 to 20 wt % cationic surfactant.

The composition preferably comprises one or more anionic surfactants, preferably less than 5 wt%, more preferably less than 2.5 wt%, most preferably less than 1 wt%, based on the weight of the total composition, of one or more anionic surfactants.

Preferably, the anionic surfactant is selected from alkylbenzene sulfonates, alkyl sulfonates, alkyl sulfonates, alkyl sulfates, salts of fluorinated fatty acids, silicones, fatty alcohol sulfates, polyoxyethylene fatty alcohol ether sulfates, a-olefin sulfonate, polyoxyethylene fatty alcohol phosphates ether and alkyl alcohol.

Preferably, the composition comprises less than 2 wt%, preferably less than 1 wt% of the composition of non-ionic surfactants, most preferably the composition is free of non-ionic surfactants. Preferably, the non-ionic surfactant is selected from aminopolyglucoside (APG), fatty alcohol ethoxylate, alkyl phenol ethoxylate and fatty acid alkoxylate and tergitol (ethoxylated alcohol).

Carrier

The antimicrobial composition preferably comprises a carrier. Preferably, the carrier is selected from water, oil, solvent, inorganic particulate material, starch, air and mixtures thereof. The carrier of the composition according to the first aspect of the invention comprises water, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol, diethylene glycol, or a mixture thereof. The carrier is preferably from 0.1 to 99% based on the weight of the total composition. The antimicrobial composition may be in form of a solid, liquid, gel, paste or soft solid and the carrier may be selected by a person skilled in the art depending on the format of the antimicrobial composition. Examples of inorganic particulate materials include clay, talc, calcite, dolomite, silica, and aluminosilicate. Examples of oils include mineral oils, oils of biological origin (e.g. vegetable oils), and petroleum-derived oils and waxes. The oils of biological origin are preferably triglyceride-based. Preferably, the carrier oil is not a perfume oil. Thus, the carrier oil preferably does not substantially contribute to the odour of the composition, more preferably it does not contribute to that odour. Examples of solvents include alcohols, ethers and acetone. The starch may be natural starch obtained from food grains or may be a modified starch.

In certain preferred embodiments, suitable solvents include, for example, water; glycols, including ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, polyethylene glycol, and polypropylene glycol; glycol ethers; alcohols, such as methanol, ethanol, propanol, phenethyl alcohol and phenoxypropanol; ketones, including acetone and methyl ethyl ketone; esters, including ethyl acetate, butyl acetate, triacetyl citrate, and glycerol triacetate; carbonates, including propylene carbonate and dimethyl carbonate; and mixtures thereof. It is preferred that the solvent is selected from water, glycols, glycol ethers, esters and mixtures thereof. In certain preferred embodiments, suitable solid carriers include, for example, cyclodextrin, silicas, diatomaceous earth, waxes, cellulosic materials, alkali and alkaline earth (e.g., sodium, magnesium, potassium) metal salts (e.g., chloride, nitrate, bromide, sulfate) and charcoal.

Thus, in many of the envisaged applications such as personal care/washing, oral care and hard surface cleaning, the antimicrobial composition may be formulated with either an aqueous base or a oil/solvent base. Compositions with an aqueous base (water being the carrier), may also for instance be products in gel format. Compositions with a purely oil/solvent base may for instance be products in anhydrous stick form or propellant- containing products.

Thus, the antimicrobial composition may for instance, preferably be an antimicrobial anhydrous stick personal care composition on a purely oil/solvent base wherein the composition has a water content of less than 0.01 wt%, and wherein the composition is preferably free of water. Alternatively, the antimicrobial composition may for instance, preferably be an antimicrobial propellant-drivable personal care composition, also comprising a propellant. Air can also be used as propellant, for instance in the form of compressed or liquefied air. However, the most preferred product format has an emulsion base (water and/or oil being the carrier) or is capable of forming an emulsion upon dilution, e.g. soap products in liquid, solid, lotion or semi-solid form for hand washing, face washing, body washing, or shaving applications; toothpaste/ dentifrices for oral care applications or products for hard surface cleaning in bar or liquid form. If the product comprises an emulsion base, it preferably also comprises one or more surfactants as described herein. Liquid and solid compositions

The antimicrobial composition may be in form of a solid, a liquid, a gel or a paste. A person skilled in the art can prepare compositions in various formats by choosing one or more carrier materials and/or surfactant. The antimicrobial compositions of the present invention are useful for cleaning and care, in particular for skin cleaning and skin care. It is envisaged that the antimicrobial composition can be used as either a leave-on product or a wash-off product, preferably a wash-off product. The antimicrobial composition of the present invention can also be used for cleaning and care of hard surfaces such as glass, metal, plastic and the like.

A particularly preferred carrier is water. When water is present, it is preferably present in at least 1 wt%, more preferably at least 2 wt%, furthermore preferably at least 5 wt%. Preferably the composition comprises water from 0.1 to 99%, more preferably from 0.5 to 95%, even more preferably from 1 to 90%, further more preferably from 3 to 85%, still more preferably from 5 to 80%, yet more preferably from 10 to 75%, still further more preferably from 20 to 65% and yet further more preferably from 30 to 50% based on the weight of the total composition. When water is the carrier, both liquid and solid compositions are possible. Different amounts of water may be preferred depending on the product format. When water is the carrier, a preferred liquid antimicrobial composition according to the invention comprises: a) a cationic surfactant; b) one or more substituted phenols selected from the group comprising thymol, sec- butylphenol, carvacrol, eugenol, propylphenol and mixtures thereof, c) one or more aliphatic terpene alcohol selected from menthol, isomenthol, neomenthol, neoisomenthol and mixtures thereof, d) one or more unsaturated terpenes selected from the group comprising limonene, alpha-terpene, terpinolene, cymene, phellandrene or mixtures thereof; and e) water, wherein the substituted phenol, the aliphatic terpene alcohol and the unsaturated terpene are present in the ratio from 1:0.5:0.5. The solid antimicrobial composition is preferably in form of a shaped solid, more preferably a bar. The solid antimicrobial composition is particularly useful for skin cleaning, in particular for hand washing or a face washing. Such a bar-shaped solid antimicrobial composition may be a soap bar. Soap bar compositions are well-known and may be similar to the following non-limiting example composition, comprising 75.6 wt% of anhydrous sodium soap, 1.0 wt% of glycerine, 0.5 wt% of sodium carbonate, 0.2 wt% of EHDP (ethane- 1 -hydroxy- 1,1- disphosphonate) acid, 0.04 wt% of EDTA (ethylenediaminetetraacetic acid) tetrasodium salt, 8.5 wt % of hydrated magnesium silicate (Talc), 0.7 wt% of sodium chloride, 0.05 wt% of dyes, 0.75 wt% perfume and water up to 100 wt Alternatively, inorganic particulate material is also a suitable carrier. When inorganic particulate material is the carrier, the antimicrobial composition is in a solid form. Preferably the inorganic particulate material is talc. When the inorganic particulate material is talc, the solid antimicrobial composition is particularly useful as a talcum powder for application on face or body.

According to another alternative, a solvent different from water is a preferred carrier.

Although any solvent can be used, alcohol is a preferred solvent. Short chain alcohols, in particular ethanol, propanol, and isopropanol, are particularly preferred as carrier for an antimicrobial wipe or an antimicrobial hand sanitiser composition.

Solvents such as ethanol and isopropanol typically demonstrate antimicrobial efficacy themselves. However, they are also volatile and may readily evaporate during application of the composition. Thus, their levels on the surface that is treated might even reduce until below the minimum level required for antimicrobial action, before the minimum period needed for disinfection has passed. In contrast, the thymol is much less volatile and may therefore yield prolonged antimicrobial action after applying them to the skin.

The composition may further comprise various additional ingredients known to a person skilled in the art. Such additional ingredients include, but are not limited to: perfumes, pigments, preservative, emollients, sunscreens, emulsifiers, gelling agents, thickening agents, humectants (e.g. glycerine, sorbitol), sequestrants (e.g. EDTA) or polymers (e.g. cellulose derivatives for structuring such as methyl cellulose).

The substituted phenols according to the invention may contribute to the olfactory properties of the composition. Although some of these compounds might be applied for instance in perfume compositions, the present invention is directed towards antimicrobial compositions. Therefore, the composition is preferably not a perfume composition, although other perfume components can be present. Here, a perfume composition is defined as a composition comprising a plurality of olfactory components, wherein the composition is solely intended to provide a harmonious scent.

Synergistic effect of the invention

The antimicrobial action of two or more active compounds is considered additive if the combined action merely results from the addition of the effects the individual components would have in isolation. In contrast, the antimicrobial action of two or more active compounds is considered to be synergistic if the combined effect of the two or more compounds is stronger than expected based on the assumption of additivity. Without wishing to be bound by theory, it is believed that the antimicrobial action of the one compound may be enhanced by the action of the other compound and vice versa. Such enhancement may for instance originate from cooperative interplay between the mechanisms of antimicrobial action at the molecular level. Such enhanced antimicrobial action may manifest itself for instance by the fact that lower concentrations of active compounds are required to obtain complete microbial kill, or alternatively, that the same extent of microbial kill is arrived at in a shorter time.

Whether an antimicrobial composition comprising two or more active compounds is capable of synergistic antimicrobial action may for instance be determined following the procedures and using the criteria as outlined in the examples hereafter. Typically, evidence of synergistic antimicrobial action may be provided at concentrations below the minimum biocidal concentrations of each of the components when taken individually. However, it is generally believed that synergistic action can still occur when the concentration of one or more of the active compounds is raised above its minimum biocidal concentration (when taken individually).

In another aspect, there is provided an antimicrobial composition comprising: a) 0.01 to 20 wt% cationic surfactant, wherein the cationic surfactant is benzalkylammonium chloride, b) 0.05 to 2 wt% substituted phenols selected from thymol, sec-butylphenol, carvacrol, eugenol, propylphenol and mixtures thereof, c) 0.025 to 1 wt% aliphatic terpene alcohols selected from menthol, isomenthol, neomenthol, neoisomenthol and mixtures thereof; and d) 0.025 to 1 wt% unsaturated terpenes selected from limonene, alpha-terpinene, terpinolene, cymene, phellandrene and mixtures thereof.

In another aspect, there is provided a method of disinfecting a surface comprising the steps of: i. applying a composition comprising: a) a cationic surfactant, b) one or more substituted phenols selected from thymol, sec-butylphenol, carvacrol, eugenol, propylphenol and mixtures thereof, c) one or more aliphatic terpene alcohols selected from menthol, isomenthol, neomenthol, neoisomenthol and mixtures thereof; and d) one or more unsaturated terpenes selected from limonene, alpha-terpinene, terpinolene, cymene, phellandrene and mixtures thereof, to a surface, and ii. removing the composition from the surface, wherein the substituted phenol, the aliphatic terpene alcohol and the unsaturated terpene are present in the ratio 1:0.5:0.5.

Preferably, the surface is a hard surface, more preferably wherein the hard surface is a kitchen, bathroom or floor surface. Typically, such hard surfaces are surfaces that require frequent cleaning and preferably also sanitisation and/or disinfection. Such surfaces may be found in many household or industrial environments, and may include kitchen and bathroom surfaces, tabletops, floors, walls, windows, utensils, cutlery, and crockery. Such surfaces may be made from many different materials, including for instance plastics, wood, metal, ceramics, glass, concrete, marble, and painted surfaces. The composition may be applied to the surface by any suitable means known to the skilled person. For instance, a suitable means may be pouring, dropping, spraying or wiping in case of liquid compositions.

Preferably, the method includes diluting or dissolving the composition with a suitable solvent, preferably water, before or whilst applying the composition to the surface. Such dissolving is particularly preferred when the composition is a solid. Alternatively, solid compositions may also be directly spread, rubbed, or sprayed, e.g. in the form of a powder. A suitable medium for rinsing the surface is water. Another suitable medium for rinsing the surface is a mixture of water and alcohol. The surface is then rinsed, preferably with sufficient amounts of water after a pre-determined period of time to remove any visible or sensory residue of the composition. Alternatively, an alcohol wipe or a water/alcohol impregnated wipe may be used to wipe the surface to be visibly free of the anti-microbial composition. The step of removing the composition (e.g. by rinsing or wiping the surface) is preferably started less than 5 minutes, more preferably less than 2 minutes, even more preferably less than 1 minute, still more preferably less than 30 seconds and yet more preferably less than 20 seconds after commencement of the step of applying the composition on the surface, because of the surprisingly fast antimicrobial action of the compositions according to the present invention. Even though partial microbial kill may be almost instantaneous upon application of the composition as claimed, it is preferred that the step of removing the composition from the surface is started after at least 5 seconds, preferably at least 10 seconds, more preferably at least 20 seconds after commencement of the step of applying the composition on the surface, in order to effect optimal antimicrobial action. Therefore, it is particularly preferred that the step of removing the composition from the surface (i.e. step ii) is started between 5 minutes and 5 seconds, more preferably between 1 minute and 10 seconds, even more preferably between 30 and 20 seconds and still more preferably between 20 and 15 seconds after commencement of the step of applying the composition on the surface (i.e. step i).

The disinfecting action of the method (as may be expressed in terms of the disinfection time T _D ) is preferably determined according to the protocol of the examples as described hereinafter. This test relates to a standardised test environment in which the microbial culture is kept in suspension. A similarly suitable test is the standard suspension method described in European Standard EN 1276, with the proviso that the disinfection time is adapted to suit the above criteria as will be clear to a person skilled in the art. Alternatively, one of the test methods as described in WO 2010/046238 may for instance be applied to establish the disinfecting action.

Alternatively, since the method is directed towards surface disinfection, the surface disinfection time T2 may also be determined by test methods involving a surface. Therefore, the invention preferably relates to a method according to the present invention, wherein the surface disinfection time T2 of said method is less than 60 seconds, preferably less than 15 seconds, wherein T2 is defined as the time starting from the moment of applying the composition to the surface to be disinfected after which the number of microbes per unit area is reduced by a factor of 10000 (i.e. a 4 log reduction), wherein the initial number of microbes preferably exceeds 103, more preferably 105, and even more preferably 107 microbes per square centimeter. Such tests may for instance be performed as described in WO 2010/046238, or as described in European Standards EN 13697:2001 and EN 1500:1997.

In a further aspect, there is provided a use of a composition as defined herein for cleaning a hard surface, preferably wherein the hard surface is a kitchen, bathroom or floor surface.

The composition and surface on which the composition is used is as defined above.

In another aspect, there is provided a non-therapeutic use of a composition as defined herein cleaning skin and/or oral cavity. Thus, there is provided a non-therapeutic use of a composition according to the invention for improved hygiene of surfaces of the human body. Such surfaces include for example the skin, hands and the oral cavity. In the context of the present application, non-therapeutic use means that the subject, whose skin, hand or oral cavity is contact with the composition defined herein, is not in need of medical treatment, e.g. the skin, hands and oral cavity are not infected in a way that requires medical attention. The skin, hands and oral cavity of the subject are contacted with the composition as defined herein in order to maintain a normal hygiene level associated with day-to-day cleanliness.

The surfaces of the human body are treated for cosmetic reasons, e.g. to look appealing. According to a preferred embodiment, the invention relates to use of a composition according to the invention for improved hand hygiene. According to another preferred embodiment, the invention relates to use of a composition according to the invention for improved oral hygiene.

In preferred embodiments, the invention relates to compositions according to the invention for use as or incorporation in home care products and personal care products. More preferably, this embodiment of the invention relates to a composition according to the invention which is a home care product or a personal care product. A "home care product" is a product for the treatment, cleaning, caring or conditioning of the home or any of its contents. The foregoing includes, but is not limited to, compositions, products, or combinations thereof relating to or having use or application in the treatment, cleaning, cleansing, caring or conditioning of surfaces, furniture and atmosphere of the home and household contents, such as clothes, fabrics and/or cloth fibres and the manufacture of all of the foregoing products. A "personal care product" is a product for cleaning of the person. The foregoing includes, but is not limited to, chemicals, compositions, products, or combinations thereof relating to or having use or application in the treatment, cleaning, cleaning or conditioning of the person (including in particular the skin, hair and oral cavity), and the manufacture of all the foregoing. Home care products and personal care products are for example products marketed under mass market brands, non-limiting examples being soap bars, deodorants, shampoos, and home surface sanitisers/disinfectants.

Another preferred embodiment of the invention relates to compositions according to the invention for use as or incorporation in industrial and/or institutional products. More preferably, this embodiment of the invention relates to a composition according to the invention which is an industrial and/or an institutional product. Industrial and institutional products are for example products being marketed under professional brands, with non limiting examples being products for industrial, institutional, janitorial, and medical cleaning, cleaning-in-place, food services, veterinary, and agricultural products.

Industrial and/or institutional products also include products for cleaning of the person (such as hand sanitisers) for medical offices, hospitals and/or other institutions.

In another preferred embodiment, the invention also relates to a method or use according to the invention involving home care products or personal care products. For example, the method according to the invention, which comprises application of a composition according to the invention in step i, can be a method wherein that composition is a composition for use as or incorporation in home care products and personal care products as described hereinabove. Similarly, in another preferred embodiment, the invention also relates to a method or use according to the invention involving industrial and/or institutional products. For example, the method according to the invention, which comprises application of a composition according to the invention in step i, can be a method wherein that composition is a composition for use as or incorporation in industrial and/or institutional products as described hereinabove. Products and/or methods for use in the home care or personal care field are generally distinct from products and/or methods for use in the industrial and/or institutional field. Thus, for example, a product that is marketed as a home or personal care product will generally not be marketed as a product for industrial and/or institutional use and vice versa. Therefore, certain embodiments of the present invention, when carried forth into practice, will relate to the one field, but not the other.

The invention shall now be exemplified by the following non-limiting examples.

EXAMPLES

Materials:

The materials used in the experiments were commercially available and were purchased from its supplier indicated below:

Thymol (T; Ronak Fine Industries)

4-Secondary butyl phenol (B; catalogue number B7033; TCI Chemicals India private limited) Eugenol (E; Nishant Aromas)

Menthol (M; catalogue number M2772; Sigma Aldrich)

D-Limonene (L; Cutrale)

Terpinolene (TP; catalogue number 86485; Sigma Aldrich)

Alpha terpinene (AT; catalogue number 223182; Sigma Aldrich)

Benzalkonium chloride (BKC)

Didecyldimethylammonium chloride (DDAC)

Cetyltrimethylammonium chloride (CTAC)

General method for assessment of antimicrobial synergy

Minimum inhibitory concentration (MIC) of the individual actives were determined by observing the lowest concentration at which no visible growth is observed (blue colour of resazurin).

The differing behaviours of inhibitory antimicrobials in isolation and mixtures have been widely explored using the concept of the Fractional Concentration and Fractional Inhibitory Concentration (FIC). See for instance J.R.W. Lambert and R. Lambert, J. Appl. Microbiol 95, 734 (2003); T. Jadavji, C.G. Prober and R. Cheung, Antimicrobial Agents and Chemotherapy 26, 91 (1984), and WO 2004/006876. These parameters can be defined as follows: Concentration of component a tested in the mixture

FIC (component A) = [MIC (component A tested in the mixture)] / [MIC (component A tested as a single active)]

Similarly, FIC (component B) = [MIC (component B tested in the mixture)] / [MIC (component B tested as a single active)] åFIC = FIC (component A) + FIC (component B) åFIC = 0.5 strong synergy / 0.75 synergy / 1 additive effect

Experimental method

Antimicrobial efficacy is tested against a representative pathogenic bacterial organism, Gram negative Escherichia coli. Concentrations of actives are expressed in terms of the percentage weight/volume (w/v.%) throughout Example 1.

Bacterial stock

An overnight culture of Escherichia coli (10536 strain) was prepared in 50 ml total volume of tryptic soy broth, grown for ca. 18 hrs at 37°C and shaken at 150 rpm. 1 ml of this E. coli culture was transferred to 50 ml of fresh TSB broth and incubated at 37 °C at 150 rpm for ca. 4 hours. This culture was separated into equal volumes and centrifuged at 4000 rpm for 15 minutes, washed with sterile saline (0.85% NaCI), centrifuged once more and re-suspended in saline to give a final concentration of 0.8 OD620, equivalent to about 10 cells per millilitre for this particular organism. Here, OD620 indicates the absorbance of a sample in a cuvette of 1.0 cm path length at a wavelength of 620 nm. This bacterial stock was used for assaying against antimicrobial actives (in triplicate).

Preparation of master plate:

20% w/w solutions of the test compositions were prepared in dimethylsulphoxide (DMSO)/ distilled water as appropriate. Stock solutions of the actives at 1:1 ratio concentration prepared by serially diluting in DMSO or water in 96 micro titre plate.

Preparation of working plate:

Final dilution of the compositions was done in second 96 micro titre screening plate by diluting the stock solution 20 times with bacterial suspension in tryptic soy broth media. For this, 10 m I of each serially diluted compositions in different concentration combinations were added to the plate and challenged with 180 pi of bacterial suspension containing 7 log CFU/ ml. The final volume of test solution was 200 pi. Plates were incubated at 37 °C for 24 hours. After 24 hours, 3 mI of 1% Resazurin was added and after few hours, the plates were visually observed. Blue color indicates test bacteria growth inhibition and development of pink colour indicates bacterial growth.

Calculation of results

MIC inhibitory concentration of the individual actives were determined by observing the lowest concentration at which no visible growth is observed (blue colour of resazurin). Then, Fractional inhibitory concentration (FIC) is determined. Fractional inhibitory concentration (FIC) is the estimate the interaction (additive effect, synergy or antagonism) between two or more actives intended to be used in combination.

FIC is calculated using the formula given above.

Example 1

Synergistic combinations of cationic surfactant (benzalkylammonium chloride, BKC) and a combination of a substituted phenol with menthol and an unsaturated terpene (Examples 1 and 2)

1. BKC + BML

2. BKC + TML

TML: thymol:menthol:limonene = 1:0.5:0.5 3. CTAC + TML

TML: thymol:menthol:limonene = 1:0.5:0.5

4. DDAC + TML

TML: thymol:menthol:limonene = 1:0.5:0.5

5. BKC + BMAT

6. BKC + EMTP

EMTP: eugenol:menthol:terpinolene = 1:0.5:0.5

7. CTAC + BMAT 8. DDAC + BMAT

Comparative example D: No Limonene

TM: thymol:menthol = 1:0.5

Comparative example E: No menthol

TL: thymoUimonene = 1:0.5

Comparative example F: No Thymol

ML: menthollimonene = 1:1