WO2009087047A1

WO2009087047A1 - Hand washing assessment method

Info

Publication number: WO2009087047A1
Application number: PCT/EP2008/068013
Authority: WO
Inventors: Kathryn Bellamy; Melanie Jane Sandel
Original assignee: Unilever Plc; Unilever N.V.; Hindustan Unilever Limited
Priority date: 2008-01-04
Filing date: 2008-12-19
Publication date: 2009-07-16
Also published as: MY178465A

Abstract

The invention provides a method for assessing the effectiveness of skin washing in a subject, comprising the steps of : (a) applying a patch to a target area of the skin of a subject before washing of the target area, followed by (b) assessing the appearance of the patch after washing of the target area; in which the patch comprises a substrate for attachment to the skin; and in which the patch is designed to undergo a visually perceptible change which is dependent on the effectiveness of the method used by the subject to wash the target area.

Description

HAND WASHING ASSESSMENT METHOD

Field of the Invention

The present invention relates to a method for assessing the effectiveness of hand washing in a subject.

Background and Prior Art

The World Health Organisation (WHO) estimates that diarrhoea and respiratory infections are responsible for two-thirds of child deaths. The vast majority of child mortality occurs among the world' s poorest populations in low- and middle- income countries.

Hands play a key role in the spread of diarrhoeal pathogens and some respiratory infections. Hand washing interrupts the transmission of disease agents and so can significantly reduce diarrhoea and respiratory infections, as well as skin infections and trachoma. Recent research has shown that washing hands with soap at critical moments (particularly after contact with human excreta and before handling food) can cut diarrhoea risk by almost half. Another recent study indicates that hand washing with soap has the potential to reduce respiratory infections by about a third.

While soap is found in most households, it is often reserved for washing clothes, dishes and bathing. Hand washing with soap is not common, though practice varies from country to country. The main reason given why rates of hand washing with soap are so low is that it is simply not a habit. The widely held belief is that if hands look clean, they are clean .

The food services and healthcare industries have developed various systems intended to address the problem of insufficient hand washing. Such systems typically involve complex hardware and elaborate electronics for sensing and monitoring the hand washing process.

US 6,029,600 describes a non-electrical device for reminding restroom users to wash and cleanse their hands. An aerosol spray can or a pump spray activated by the opening of the restroom door releases a visible dye stain onto the hand of the user. The stain is removed by the cleanser supplied in the restroom.

US2005/0231373 describes a similar marking mechanism in the form of a standalone device. A removable dye is applied to the hands of a user pressing down on an absorbent pad containing the dye. The device also incorporates an audible signal which is triggered when marking takes place and serves as an alert to a person monitoring hand washing that marking has occurred.

Both the above devices involve a significant amount of hardware and are not suitable for use in a domestic setting by low-income consumers.

GB-A-2420783 describes a method of reducing or eliminating cross-contamination, for example in the context of a surface which provides a potential infection risk such as a surgical incision or a wound dressing, by applying a gel containing a UV fluorescent dye on or near to the surface. The gel is transferred to a surface coming into contact with the infection risk, and acts as a marker for cross- contamination .

WO-A-95/05417 describes an adhesive hydrogel product which is said to be suitable for inter alia the production of sheet products such as wound dressings.

Another problem associated with the above devices is that the location of hand marking is user-dependent, since actuation of the devices by the user produces the mark. Accordingly it is not always possible to ensure that marking is applied to specific areas of the hand such as the fingertips, where cleansing is most important for disease prevention. This is especially the case where the users of the device are young children.

Also, direct application of marker dye to the skin may cause smearing or staining of the dye onto areas of the skin or other articles which it is not desired to mark. This is especially the case when the particular dye used does not dry quickly upon application.

The present invention provides a low-cost and effective method to promote the use of soap, and in particular hand washing with soap, without recourse to expensive hardware or electronics. The invention also provides a solution to the problem of ensuring targeted marking of specific areas such as fingertips without smearing or staining.

Summary of the Invention

The invention provides a method for assessing the effectiveness of skin washing in a subject, comprising the steps of:

(a) applying a patch to a target area of the skin of a subject before washing of the target area, followed by

(b) assessing the appearance of the patch after washing of the target area;

in which the patch comprises a substrate for attachment to the skin;

and in which the patch is designed to undergo a visually perceptible change which is dependent on the effectiveness of the method used by the subject to wash the target area.

Detailed Description of the Invention

The method of the invention is particularly suitable for use by a parent or caregiver to check that their children have washed their hands effectively. One of the key elements of effective hand washing is the use of a cleansing composition such as soap, or other anionic surfactant, rather than water alone.

Accordingly it is preferred that the patch for use in the method of the invention is designed to undergo a visually perceptible change after a suitable period of washing which is dependent on the use of soap, or other anionic surfactant. In this way, assessment of the appearance of the patch after washing provides an indication to the assessor whether soap, or other anionic surfactant, has or has not been used to wash the target area.

By "suitable period" in the context of this invention is generally meant a period of washing up to about 5 minutes, preferably up to about 45 seconds, more preferably from 5 to 45 seconds, most preferably from 10 to 40 seconds, ideally from 15 to 35 seconds.

By "visually perceptible" in the context of this invention is meant visible to the naked eye. Preferably the patch undergoes visually perceptible fading, more preferably complete disappearance, after a suitable period of washing (as defined above) with soap, or other anionic surfactant.

In a preferred embodiment, the patch is provided in the form of a transfer or sticker which will wash off the skin after a suitable period of washing with soap, or other anionic surfactant, but which will not wash off the skin (or will wash off to a significantly lesser extent) , after an equivalent period of washing with water alone. In a particularly preferred embodiment, the transfer or sticker is designed to be applied to the fingertips, where cleansing is most important for disease prevention.

Accordingly, a most preferred method according to the invention comprises the steps of:

(a) applying a transfer or sticker to a target area of the skin (preferably a fingertip) of a subject before hand washing; followed by

(b) assessing the appearance of the transfer or sticker after hand washing;

in which the transfer or sticker comprises a solid or semisolid film as the substrate for attachment to the skin, the film bearing a colorant,

and in which the transfer or sticker will wash off the skin after a suitable period of washing with soap, or other anionic surfactant, but which will not wash off the skin (or will wash off to a significantly lesser extent) , after an equivalent period of washing with water alone.

The transfer or sticker is ideally of a size and shape which is small enough to be applied to a fingertip of a subject (usually a young child) , yet large enough to be easily visualised by the naked eye during use. A suitable example would be a small disc having a diameter ranging from 1 to 10 mm, preferably from 2 to 5 mm. Alternatively, a shape designed to appeal to children or a logo may be used, having generally similar dimensions. Also, a range of different sizes could be provided in the form of a set, so that a parent or caregiver can select the most appropriate size for their child.

Transfers or stickers suitable for use in the above method may suitably be prepared from a mixture containing at least one colorant, at least one film-forming polymer and a solvent .

By "film-forming polymer" means a polymer capable of forming, by itself or in the presence of an auxiliary film- forming agent, a macroscopically continuous film that adheres to keratin materials, preferably a cohesive film and more preferably a film whose cohesion and mechanical properties are such that the film can be isolated and handled in isolation, for example when the film is made by pouring or casting the mixture onto a surface such as a nonstick backing paper. The film could alternatively be obtained by casting, blow-moulding, extrusion or blown extrusion of the film-forming polymer.

Advantageously, the film-forming polymer serves to entrap or immobilise the colorant, which helps to reduce the risk of smearing or staining of the colorant onto areas of the skin or other articles which it is not desired to mark. It also enables a wider variety of colorants to be used in the method of the invention, compared to prior art methods requiring direct application of colorant to the skin.

A preferred method for making a transfer or sticker suitable for use in the invention comprises the following steps:

(a) preparing a mixture containing at least one colorant, at least one film forming polymer and a solvent;

(b) pouring or casting the mixture onto a surface such as a non-stick backing paper, and

(c) drying the mixture so as to form a solid or semisolid film on the surface, the solid or semi-solid film bearing the colorant.

Such a transfer or sticker is typically transferred to skin by placing the solid or semisolid film on the skin with the non-stick backing paper uppermost, moistening the backing paper, and applying gentle pressure before peeling off the non-stick backing paper, leaving the film adhered to the skin .

A suitable mixture for use in making a transfer or sticker according to the above method comprises the following components :

(a) from 5 to 30%, preferably from 10 to 20% by weight of at least one film-forming polymer; (b) from 0.01 to 10%, preferably from 0.1 to 5% by weight of at least one colorant, and

(c) the balance solvent, preferably water.

Preferred film-forming polymers for use in the invention form a film whose removability from the skin is sufficiently dependent on the use of soap, or other anionic surfactant, such that assessment of the appearance of the transfer or sticker after washing provides an indication to the assessor whether soap, or other anionic surfactant, has or has not been used to wash the target area.

Particularly preferred film-forming polymers form a film which will wash off the skin after a suitable period of washing with soap, or other anionic surfactant, but which will not wash off the skin (or will wash off to a significantly lesser extent) , after an equivalent period of washing with water alone.

Film-forming polymers can be of synthetic origin or of natural origin, and can be of nonionic, cationic, anionic or amphoteric character.

Examples of suitable film-forming polymers include:

synthetic, nonionic film-forming polymers such as homopolymers of vinyl pyrrolidone, homopolymers of N-vinyl formamide, copolymers of vinyl pyrrolidone and vinyl acetate, copolymers of vinyl pyrrolidone and dimethylaminoalkylmethacrylates, in which alkyl means methyl, ethyl or propyl, terpolymers of vinyl pyrrolidone, vinyl acetate and vinyl propionate, polyacrylamides, polyvinyl alcohols, polyethylene glycols and polyethylene glycol/polypropylene glycol copolymers;

synthetic, anionic, film-forming polymers such as branched or non-branched vinyl acetate/crotonic acid copolymers, terpolymers of acrylic acid, alkyl acrylates and N- alkylacrylamides, (such as acrylic acid/ethyl acrylate/N-t- butylacrylamide terpolymers) , vinyl pyrrolidone/vinyl acrylate copolymers, terpolymers of vinyl acetate, crotonate and vinyl alkanoate (such as vinyl acetate/crotonate/vinyl neodecanoate copolymers) and methyl vinyl ether/maleic acid anhydride copolymers and their monoesters;

synthetic, cationic, film-forming polymers such as copolymers of vinylpyrrolidone and quaternized derivatives of dialkylaminoacrylate and dialkylaminomethacrylate, copolymers of vinylpyrrolidone and methylvinylimidazolium salts (e.g. chloride), terpolymers of dimethyl diallyl ammonium chloride, sodium acrylate and acrylamide, terpolymers of vinylpyrrolidone, dimethylamino ethyl methacrylate and vinyl caprolactam, polymeric quaternary ammonium salts of hydroxyethylcellulose reacted with a trimethyl ammonium substituted epoxide, copolymers of vinylpyrrolidone and methacrylamidopropyltrimethylammonium chloride, diquaternary polydimethylsiloxanes, cationic diallyl quaternary ammonium-containing polymers (such as dimethyldiallylammonium chloride homopolymer and copolymers of acrylamide and dimethyldiallylammonium chloride and cationic polyacrylamides; natural or naturally-derived film-forming polymers such as chitosan, hydroxyalkylchitosan, hydroxyalkylchitin, shellac, polyaminoacids, peptides, starch, modified starch, gelatin, sodium alginate, xanthan gum, tragacanth gum, guar gum, acacia gum, arabic gum, pectin, carrageenan, dextrin, maltodextrin, polydextrose, pullulan, cellulose and cellulose derived film-forming polymers (such as methylcellulose, ethylcellulose, propylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose and hydroxypropylmethylcellulose) ;

synthetic, amphoteric, film-forming polymers such as dimethyldiallylammonium chloride/acrylamide/acrylic acid terpolymers, copolymers of acrylic acid and dialkyldiallylammonium salts (such as dimethyldiallylammonium chloride) ,

(meth) acrylethylbetaine/alkyl (meth) acrylate copolymers (such as N-methacryloyloxyethyl-N, N-dimethylammonium-α-N- methylcarboxybetaine/alkyl methacrylate copolymers) , sodium acrylate/acrylamidopropyltrimethylammonium chloride copolymers and octylacrylamide/acrylates/butylaminoethyl methacrylate copolymers.

A preferred class of suitable film-forming polymers for use in the invention are naturally-derived film-forming polymers, in particular the cellulose derived film-forming polymers as described above. Particularly preferred is hydroxyethylcellulose . Another preferred class of suitable film-forming polymers for use in the invention are the synthetic, amphoteric, film-forming polymers as described above. Particularly preferred is a copolymer of acrylic acid and dimethyldiallyl ammonium chloride, also known as Polyquaternium-22 and commercially available with trade name MERQUAT 280.

Mixtures of any of the above described materials could also be used, in order to achieve preferred film forming capabilities, mechanical properties, and kinetics of dissolution .

A preferred mixture for use in the invention is a mixture of at least one cellulose derived polymer as described above, with at least one synthetic, amphoteric, film-forming polymer as described above. A particularly preferred mixture for use in the invention is a mixture of hydroxyethylcellulose and Polyquaternium-22. Films formed from this mixture retain their shape and adhere to skin well. They also retain colorant well, thereby reducing bleeding or smearing of colorant onto surrounding skin during use.

Any colorant may be used in the invention, provided it is safe for application to the skin, has a desirable colour and is compatible with the other components of the transfer or sticker .

The colorant can include, for example, a pigment or a dye, or a combination of a pigment and a dye. Pigments are generally not water-soluble or less water soluble than dyes. Examples of suitable dyes and pigments are listed in the Table below. The Colour Index numbers (C.I.) are taken from the Rowe Colour Index, 3rd edition, Society of Dyers and Colourists , Bradford, England, 1971.

- Ii

Mixtures of any of the above described dyes and pigments may also be used, in order to achieve the desired colour.

Preferred colorants impart a bold, distinctive colour to the transfer or sticker which enables easy visualisation. Examples of preferred colours are blue, red, green, orange, yellow, black and violet. Specific examples of preferred colorants include indigo carmine (C.1.73015) and Allura Red AC (CI. 16035) .

The invention is further illustrated with reference to the following, non-limiting example, in which all percentages are by weight based on total weight unless otherwise specified.

EXAMPLE

A transfer mixture was prepared having the formulation as shown in the following Table:

5μl and lOμl aliquots of the above mixture were dropped onto transfer paper (obtained from The Magic Touch (GB) Ltd.) and allowed to dry to form coloured spots of polymer film.

The coloured spots of polymer film were applied to the fingertips of 16 test subjects, by applying the transfer paper (polymer film side down) onto the skin of the fingertip with gentle pressure, followed by moistening and removing the transfer paper, leaving the spot of polymer film adhered to the skin as a transfer. The test subjects then washed their hands for 30 seconds.

The hands of the test subjects were then visually assessed in order to ascertain the degree of removal of the transfer.

The degree of removal of the transfer varied significantly between individual panellists, from complete removal in some cases to no removal. This shows that the degree of removal of the transfer is dependent on individual handwashing technique. Accordingly, the transfer can be used as an indicator of proper handwashing technique.

Experiments were also carried out in which the panellists washed their hands using water alone. It was observed that water alone could remove a little of the transfer, but washing with soap and water improved removal enormously. Accordingly, the transfer can be used as an indicator of whether soap has (or has not) been used in the handwashing process .

Claims

1. A method for assessing the effectiveness of skin washing in a subject, comprising the steps of:

(b) assessing the appearance of the patch after washing of the target area;

in which the patch comprises a substrate for attachment to the skin;

2. A method according to claim 1, comprising the steps of:

(a) applying a transfer or sticker to a target area of the skin (preferably a fingertip) of a subject before hand washing, followed by

(b) assessing the appearance of the transfer or sticker after hand washing;

in which the transfer or sticker comprises a solid or semisolid film as the substrate for attachment to the skin, the film bearing a colorant, and in which the transfer or sticker will wash off the skin after a suitable period of washing with soap, or other anionic surfactant, but which will not wash off the skin (or will wash off to a significantly lesser extent) , after an equivalent period of washing with water alone.

3. A method according to claim 2, in which the transfer or sticker is prepared from a mixture containing at least one colorant, at least one film-forming polymer and a solvent.

4. A method according to claim 3, in which the mixture comprises the following components:

(a) from 5 to 30%, preferably from 10 to 20% by weight of at least one film-forming polymer;

(b) from 0.01 to 10%, preferably from 0.1 to 5% by weight of at least one colorant, and

(c) the balance solvent, preferably water.

5. A method according to claim 3 or claim 4, in which the film-forming polymer is a cellulose derived film-forming polymer, or a synthetic, amphoteric, film-forming polymer or a mixture thereof.

6. A method according to claim 5, in which the film-forming polymer is a mixture of hydroxyethylcellulose and Polyquaternium-22.

7. A method according to any one of claims 2 to 6, in which the transfer or sticker is coloured blue, red, green, orange, yellow, black or violet.