Field of Invention

This invention relates to aerosol compositions for sanitising or disinfecting animate as well as inanimate surfaces.

Background

Sanitisers, sometimes called disinfectants, antiseptics or antimicrobials are compositions that are applied to living tissues, e.g. skin, to reduce the possibility of infection. Sanitisers are generally used to denote compositions that provide instantaneous kill of microbes on topical surfaces of animal or human body while disinfectants are generally used for the killing germs on non-living surfaces. Sanitisers often involve use of alcohol-based microbicides. These are used by applying a few drops of the solution on to the topical surface e.g. the hands and then rubbed together. During rubbing, the alcohol and other antimicrobial substances spread on the desired surface causing the antimicrobial action. Parallelly, the alcohol evaporates leaving the surface disinfected without the need for rinsing it with water and subsequent drying as is necessary in the case of soap or other handwash products. Sanitisers are useful in hospitals, clinics, nursing homes and other healthcare places where doctors, nurses and other healthcare workers need to disinfect their hands, often several times an hour, as they attend to one patient after another to minimize the spread of diseases through contact. These are distinguished from antibiotics by the latter's ability to be transported through the lymphatic system to destroy bacteria within the body.

Human skin, i.e. the epidermis generally harbours several different microorganisms in concentrations exceeding millions or even billions of colony forming units (cfu) per square centimetre (cm ² ). Some microorganisms are harmless, but there are also various pathogenic species present, such as E. coli or S. aureus and a variety of viruses. Also, other unwanted bacteria may also inhabit the skin, such as S. epidermidis, which is generally non-pathogenic, but is believed to cause an unpleasant body odour.

Similarly, hand hygiene has continued to be an important practice advocated for preventing the spread of many diseases. A variety of cleansing and sanitising products are available for such purpose including soap bars, liquid soaps, alcohol-based sanitising sprays, gels and tissues.

Surfaces can be broadly distinguished based on the fact whether they belong to a living organism or a non-living thing. Animate surfaces are surfaces of a living organism, especially human beings. On the other hand, inanimate surfaces are of non-living things such as table-tops, chairs, cupboards, tiles and the like.

High-touch surfaces are those that are handled frequently throughout the day by numerous people. These inanimate surfaces include doorknobs, light switches, phones, sink faucets, and toys. High-touch surfaces can become contaminated by direct contact with bodily fluids or through indirect contact with other contaminated objects, such as inadequately cleaned rags and sponges or improperly washed hands. Pathogens can continue to stay on such and other animate surfaces if they are not properly sanitised or disinfected. For example, certain viruses and bacteria are known to survive at least for many hours.

W02006/050776 A1 (Unilever) discloses antiperspirant aerosol product in which the antiperspirant active is dissolved in water, the resulting aqueous solution is emulsified in an oily continuous phase, and the oil-in-water emulsion composition is packaged in a dispensing device comprising a particular selection of lacquered components.

US6299862 B (Tom Barrow, 2001) discloses delivery of a sanitiser to a personal use surface, such as a toilet seat surface. The sanitiser has a dispensing unit for delivery of the sanitiser as an aerosol spray, leaving only the sanitiser in pure form on the seat surface. This results in quick drying of the surface in 12 to 15 seconds. It is disclosed that the ratio of alcohol:propellant at 70:30 combination is optimal for ensuring that only pure alcohol is delivered to the seat surface. Further it is disclosed that 85:15 proportion of isobutane:propane, as propellant, provides for optimum surface contact i.e. the composition does not disappear into the atmosphere but permits the wetting of the surface with pure alcohol. The composition is anhydrous. An aerosol can contains one fluid that boils well below room temperature (called the propellant) and one that boils at a much higher temperature (called the product, also referred to as forming part of the “base”). The product is the substance intended for topical application, such as a fragrance or room-freshener or an insect repellent. The propellant is the means of getting the product out of the can. Both fluids are stored in a sealed metal can.

Generally aerosol compositions are fragranced (i.e. perfumed) and contain a denatured alcohol, usually ethanol, a propellant, which may be a blend of short-chain hydrocarbons, and water. Usually the amount of water in the packaged composition (in can) is maintained around 7 to 8 wt% of the composition and it is balanced carefully with the amount of the alcohol and the propellant.

US2004259951 A1 (Unilever) discloses anti-microbial composition including aerosols, comprising at least 25% C1 to C4 monohydric alcohol carrier fluid, an iron (III) chelator having an iron (III) binding constant of 1023 or greater; a solubility promoter selected from the group consisting of: water; an organic amine; a polyhydric alcohol or derivative thereof; a volatile propellant having fluorine-carbon or oxygen-carbon bonds; any combination of (a) to (d). The transitional metal chelator serves as an active anti microbial, whilst the carrier fluid-solubility promoter mixture enables the formation of a stable composition. Preferred compositions are homogeneous solutions.

EP0180483 A2 (Rutland, 1985) discloses fine dispersion spray and emulsion as an oral spray or a mouthrinse with water and comprising a potable mono-, di- or polyhydric alcohol or mixture thereof as non-aqueous carrier base, and a substantially water- insoluble surfactant such as lecithin, the agent being in the form of a stable solution or suspension which, when released from pressure and mixed with air or water, forms an unstable aerosol or hydrosol respectively which then achieves a more stable state by coating out on a surface, such as teeth or gums to loosen plaque and reduce adhesive forces.

GB1595649 A (National Starch, 1981) discloses that shelf life and metal container corrosion of hair spray resin formulations can be addressed by addition of small amounts of water to the hair spray resin and it also improves the stability. Addition of water improves the color stability of the polymer solution of the aerosol container.

JP03176417 (San El Chem, 1991) discloses a mouth spray aerosol where the propellant forms 5 to 95 wt%.

US5565193 A (Procter & Gamble) discloses hair styling compositions including aerosol comprising silicone grafted adhesive polymer, 0.5 to 15% C10-C14 branched chain hydrocarbons a polar solvent phase such as water, alcohols, comprising 80 to 98.9% of the composition. The compositions also comprise 10% to 60% propellant.

Summary of the Invention

We have now unexpectedly determined that a significant reduction in wt% of water, along with a rebalance of alcohol and the propellant surprisingly provides a very wet spray. Therefore, we have surprisingly determined that the aerosol compositions of this invention have better sanitising properties as compared to compositions of prior art. Accordingly the compositions of this invention are useful for sanitising a variety of animate as well as inanimate surfaces by direct aerosol spray on the surface.

In accordance with a first aspect of the invention is disclosed an aerosol composition comprising: a) 60 wt% to 80 wt% ethanol, propanol, isopropanol or a mixture thereof; b) 15 wt% to 35 wt% propellant; and, c) 1 wt% to 5 wt% water wherein said composition comprises 0.1 wt% to 2 wt% humectant selected from propylene glycol, dipropylene glycol or glycerol and wherein ratio of base: propellant is 70: 30 to 80: 20 parts by weight, where said base comprises every ingredient other than said propellant.

In accordance with a second aspect of the invention is disclosed an aerosol product comprising: a) an aerosol composition of the first aspect and, b) a container-dispenser comprising a can, valve cup and dispensing means, wherein internal surfaces of the can and valve cup are coated with an epoxy resin.

In accordance with a third aspect of the invention is disclosed an aerosol composition of the first aspect for use as a hand sanitiser.

In accordance with a fourth aspect of the invention is disclosed a non-therapeutic method of sanitising an animate or inanimate surface, comprising a step of topical spray application of an aerosol composition comprising: a) 60 wt% to 80 wt% ethanol, propanol, isopropanol or a mixture thereof; b) 15 wt% to 35 wt% propellant; and, c) 1 wt% to 5 wt% water wherein said composition comprises 0.1 wt% to 2 wt% humectant selected from propylene glycol, dipropylene glycol or glycerol and wherein ratio of base: propellant is 70: 30 to 80: 20 parts by weight, where said base comprises every ingredient other than said propellant.

In accordance with a fifth aspect of the invention is disclosed non-therapeutic use of an aerosol composition comprising: a) 60 wt% to 80 wt% ethanol, propanol, isopropanol or a mixture thereof; b) 15 wt% to 35 wt% propellant; and, c) 1 wt% to 5 wt% water wherein said composition comprises 0.1 wt% to 2 wt% humectant selected from propylene glycol, dipropylene glycol or glycerol and wherein ratio of base: propellant is 70: 30 to 80: 20 parts by weight, where said base comprises every ingredient other than said propellant for sanitising an animate or an inanimate surface.

Herein, all amounts, percentages and ratios are by weight, unless otherwise indicated. In addition, all percentages are by weight of the total composition.

Herein, all amounts, percentages and ratios are to be understood as prefixed by the word “about”. Herein, “propellant” means a gas capable of being liquefied by compression and having a boiling point of less than 10°C and preferably less than 0°C.

Herein, any material, ratio or weight indicated as “preferred” is to be understood as preferably used in combination within any other material, ratio or weight indicated as “preferred”.

Herein, the word “comprising” and “comprised of”, etc., should be understood as meaning that other components/features could also be present; i.e. the listed steps or options need not be exhaustive.

Detailed Description

The aerosol composition of the invention comprises: a) 60 wt% to 80 wt% ethanol, propanol, isopropanol or a mixture thereof; b) 15 wt% to 35 wt% propellant; and, c) 1 wt% to 5 wt% water wherein said composition comprises 0.1 wt% to 2 wt% humectant selected from propylene glycol, dipropylene glycol or glycerol and wherein ratio of base: propellant is 70: 30 to 80: 20 parts by weight, where said base comprises every ingredient other than said propellant.

The composition requires the presence of a propellant which is a volatile ingredient. A volatile propellant serves to pressurise the composition within a dispensing device and to enhance spray formation when the composition is released from the dispensing device via a spray nozzle. When a volatile propellant is present the benefit of the invention is particularly relevant - corrosion resistance being particularly important in a pressurised system.

It is preferred that the propellant is at least one of difluoroethane, propane, butane or isobutane or combinations thereof. More preferred are those volatile propellants that are gases at standard temperature and pressure, but are present in the composition in a liquefied state prior to release from a suitable dispensing device. It is preferred that boiling point of the propellant is less 0°C.

The composition comprises 15 wt% to 30 wt% propellant. While the propellant may be entirely just one of the propellants named hereinbefore, it is preferred that at least 40 parts by weight of the propellant is n-butane. Preferably 40 to 50 parts by weight of the propellant is n-butane. It is more preferred that the propellant further comprises at least one of isobutane and propane. It is even more preferred that the propellant comprises n- butane, isobutane and propane where at least 40 parts by weight of the propellant is n- butane. Other suitable ingredients include pentane and isopentane and mixtures of two or more thereof. Other preferred propellants are isobutane, isobutane/isopropane, isobutane/propane and mixtures of isopropane, isobutane and butane.

The aerosol composition of the invention comprises 60 wt% to 80 wt% ethanol, propanol, isopropanol or a mixture thereof. More preferably the composition comprises 60 wt% to 75 wt% ethanol, propanol, isopropanol or a mixture thereof. Further preferably in the 60 wt% to 80 wt% ethanol, propanol, isopropanol or mixture thereof, at least 80 parts by weight is ethanol. The alcohol is preferably either pure alcohol or denatured alcohol. More preferably the alcohol is entirely ethanol, further preferably specially denatured (SD) ethanol which contains a denaturing agent like t-butyl alcohol.

Alternatively, the composition comprises 65 wt% to as high as 95 wt%, preferably 60 to 80 wt% ethanol, propanol, isopropanol or a mixture thereof.

The composition of the invention comprises 0.1 wt% to 2 wt% humectant selected from propylene glycol, dipropylene glycol or glycerol. More preferably the humectant is propylene glycol. The humectant may aid in countering the drying effects of the 60 wt% to 80 wt% ethanol, propanol, isopropanol or a mixture thereof when the composition is applied to the human skin, in particular the hands.

It is preferred that the composition comprises 2 to 4 wt % water. Alternatively, the water content may be 1 to 15 wt%, preferably 1 to 12 wt% and more preferably 1 to 10 wt%.

Further preferably the aerosol composition of the invention is devoid of fragrance ingredients. A fragrance (also referred to as perfume) is typically composed of multiple different accords or notes and may be selected as desired. The presence of a fragrance usually enhances the treating of body odour, whether by a masking effect or otherwise. The fragrance may be in the form of a free (non-encapsulated) fragrance or it may be encapsulated in one of the multiple encapsulating materials used for this purpose. Useful components of the fragrance include materials of both natural and synthetic origin. They include single compounds and mixtures. Specific examples of such components may be found in the current literature, e.g., in Fenaroli's Handbook of Flavour Ingredients, 1975, CRC Press; Synthetic Food Adjuncts, 1947 by M. B. Jacobs, edited by Van Nostrand; or Perfume and Flavour and Chemicals by S. Arctander 1969, Montclair, N.J. (USA). These substances are well known to the person skilled in the art of perfuming and/or aromatizing consumer products, i.e. , of imparting an odour to a consumer product that is traditionally perfumed, or of modifying the odour of the consumer product.

In the composition of the invention, the ratio of base: propellant is 70: 30 to 80: 20 parts by weight, where said base comprises every ingredient other than said propellant.

In accordance with a second aspect of the invention is disclosed an aerosol product comprising: a) an aerosol composition of the first aspect and, b) a container-dispenser comprising a can, valve cup and dispensing means, wherein internal surfaces of the can and valve cup are coated with an epoxy resin.

Preferably the container-dispenser is made of aluminium or tinplate or steel. Numerous lacquers are available for the protection of aluminium or tinplate can bodies and mounting cups. Examples of such lacquers include epoxyphenolic resin (also called epon-phenolic and often abbreviated to “epoxy” or “EPON”); poly(ethylene terephthalate) (PET); polypropylene; organosol (also called EP-Vinyl or Micoflex); and polyamide imide resin (also called PAM or PAI). An epoxy resin as a lacquer is used on the internal surfaces of the can and valve cup. This performs well in terms of corrosion resistance of the can when the composition is in accordance with the first aspect of the invention.

The aluminium or tinplate can may also be lacquered on its outside; however, it is its internal surface that is coated with an epoxy resin. The resin is applied to the internal surface of the can by methods known in the art. The layer is preferably of thickness from 1 to 50 microns at all points on the internal surface of the can.

It is preferred that the aerosol composition is packed in said container-dispenser at a vapor pressure of 30 to 50 psi, at 20°C.

The mounting cup used with the present invention serves to close off the can body at its top, typically at a narrowed or ‘necked’ section of the body. The bottom of the mounting cup may contact the composition contained within the body of the can. The mounting cup typically has a valve present in a hole in its centre. In use, opening of the valve allows the aerosol composition to leave the can body via a nozzle and thereby produce a spray.

The mounting cup may be lacquered on its top side; however, it is its bottom side that is more frequently in contact with the composition and it is this side that is also preferably protected by an epoxy resin in the second embodiment of the invention. The resin is a layer of material applied to the bottom surface of the mounting cup by methods known in the art. The layer is preferably of thickness from 1 to 500 microns at all points on the internal surface of the mounting cup, the high maximum being due to the difficulty of applying lacquer to the mounting cup because of its highly contoured surface. The average thickness of the layer is preferably from 1 to 50 microns and may be measured by making 10 or more measurements at random positions on the bottom side of the mounting cup.

In order to further enhance corrosion resistance, it is preferred that the mounting cup, like the can body, is made from aluminium or tinplate or steel. For the same reason, it also preferred that the mounting cup is coated on its top side with epoxy resin, as well as on its bottom side. It is further preferred that the dispensing means of the container-dispenser comprises a valve devoid of a vapour phase tap (VPT). It is believed that absence of the VPT allows the formulation to pool, especially in the hands when the aerosol composition is used to sanitise hands.

In accordance with a third aspect of the invention is disclosed an aerosol composition of the first aspect for use as a sanitiser. More preferably the use is a hand sanitiser.

Preferably the hands are sanitised by a reduction in the number of microbes present on the hands. It is further preferred that the reduction is due to microbial kill. Further preferably at least 99.9 % of the microbes are killed. Microbial kill may alternatively be expressed as log-reduction where "2 log" reduction means that the number of viable microbes is reduced by 99 percent. By "4 log" reduction it is meant that the number of viable microbes is reduced by 99.99 %. It is yet further preferred that the said microbes are bacteria. More preferably the bacteria include Gram-positive and Gram-negative bacteria, where said Gram-positive bacteria include S. aureus and said Gram-negative bacteria include E. coli. It is particularly preferred that efficacy of the compositions of the invention is measured in accordance with BS EN 1276:2009 (modified) as herein described.

In accordance with a fourth aspect of the invention is disclosed a non-therapeutic method of sanitising an animate or inanimate surface, comprising a step of topical spray application of an aerosol composition comprising: a) 60 wt% to 80 wt% ethanol, propanol, isopropanol or a mixture thereof; b) 15 wt% to 35 wt% propellant; and, c) 1 wt% to 5 wt% water wherein said composition comprises 0.1 wt% to 2 wt% humectant selected from propylene glycol, dipropylene glycol or glycerol and wherein ratio of base: propellant is 70: 30 to 80: 20 parts by weight, where said base comprises every ingredient other than said propellant.

The method is non-therapeutic in nature. The most preferred animate surface is human hands, although other surfaces may also be sanitised. Alternatively, the method is for an animate surface and is therapeutic in nature. In this case it is preferred that the animate surface is human hands.

When the method is for an inanimate surface, preferably the inanimate surface is toilet seat, although the present invention may serve to sanitise any other inanimate surface that is amenable to be so sanitised.

In accordance with a fifth aspect of the invention is disclosed non-therapeutic use of an aerosol composition comprising: a) 60 wt% to 80 wt% ethanol, propanol, isopropanol or a mixture thereof; b) 15 wt% to 35 wt% propellant; and, c) 1 wt% to 5 wt% water. for sanitising an animate or an inanimate surface, wherein said composition comprises 0.1 wt% to 2 wt% humectant selected from propylene glycol, dipropylene glycol or glycerol and wherein ratio of base: propellant is 70: 30 to 80: 20 parts by weight, where said base comprises every ingredient other than said propellant.

The use is for an animate surface and is non-therapeutic in nature. Preferably the animate surface is human hands. Alternatively the use is for an animate surface and is therapeutic in nature. In such cases it is preferred that the animate surface is human hands. When the use is for an inanimate surface, it is preferred that the inanimate surface is toilet seat, although the present invention may serve to sanitise any other inanimate surface that is amenable to be so sanitised

The invention will now be explained with the help of exemplary non-limiting examples.

Examples

Example 1

The aerosol composition of Table 1 , in accordance with the invention, was packaged in a standard 75 ml, container-dispenser made of aluminium. The aerosol composition detailed in Table 1 was prepared and filled by a method known in the art. The container- dispenser had a can, valve cup and dispensing means. Internal surfaces of the can and valve cup were coated with an epoxy resin but the valve was devoid of a vapour phase tap (VPT).

Table 1

Note: the base: propellant ratio was 75: 25 parts by weight and in one case the composition of the propellant was as in column A of Table 2 below. In the other example it was as in column B.

Table 2

Evaluation of efficacy:

Samples of the composition of Table 1 (with propellant [A] of Table 2) evaluated in accordance with the principles outlined in BS EN 1276:2009 (modified) under the following test conditions.

BS EN 1276 is a European Standard which specifies a test method and the minimum requirements for bactericidal activity of chemical disinfectant and antiseptic products that form a homogeneous, physically stable preparation when diluted with hard water or - in the case of ready-to-use products - with water. It is a Quantitative suspension test for the evaluation of bactericidal activity of chemical disinfectants and antiseptics used in food, industrial, domestic and institutional areas.

Product Concentration: Neat as supplied (80%)

Contact Time: 30 seconds Organic Challenge: 0.3% bovine albumin (Dirty Conditions)

Temperature: Ambient (22°C)

Test Organisms: Staphylococcus aureus #255 ATCC 6538

Escherichia coli #256 ATCC 8739

Results are summarised in Table 3.

Table 3 The term "log reduction" as used herein means a 10-fold or 90 percent reduction in the number of viable microorganisms. By "2 log" reduction it is meant that the number of viable bacteria is reduced by 9.9 percent. By "4 log" reduction it is meant that the number of viable bacteria is reduced by 99.99 percent. The data in Table 3 indicates that the composition of the invention brings about significant reduction in the number of microbes due to microbial kill. More than 99.9 % of said microbes are killed because the log-reduction is more than 5. Therefore, the composition is useful to sanitise a variety of surfaces, primarily human hands.