WO2005098426A1

WO2005098426A1 - Skin sensitivity test device and method

Info

Publication number: WO2005098426A1
Application number: PCT/GB2005/001334
Authority: WO
Inventors: John Anthony Bolbot
Original assignee: John Anthony Bolbot
Priority date: 2004-04-07
Filing date: 2005-04-06
Publication date: 2005-10-20
Also published as: GB2412872A; GB0407876D0; GB0506938D0

Abstract

A test patch (1) has a reservoir layer (4) containing a first component of a multiple-component composition, such as a colourant component of a reactive hair dye formulation, and an adhesive layer (5), protected by a peelable film (6), by which it may be stuck to an area of skin (7). The test patch (1) also has a porous or apertured layer (3), protected by a removable release paper (2) or a replaceable equivalent, through which a second component of the multiple-component composition, such as an oxidiser component of the hair dye formulation, may be added to the reservoir layer (4). Alternatively, each component is added to an empty reservoir layer (4) through the porous layer (3). The components min and react within the reservoir layer (4) and pass through the adhesive layer (5) to the skin (7). The skin (7) is thus exposed to every chemical species present in the hair colouring process. The test patch (1) is removed after a set period and the skin (7) is assessed for irritation or inflammation, e.g. due to allergic reactions.

Description

SKIN SENSITIVITY TEST DEVICE AND METHOD

The present invention relates to a testing method and device for determining the sensitivity of skin to topically applied chemical compositions. More particularly, but not exclusively, it relates to a method and device for assessing an individual's sensitivity to cosmetic products such as hair colouring products.

There is increasing concern regarding adverse skin reactions to compounds which are present in commercial hair dye preparations. Examples of such compounds which are known to cause significant reactions with particular individuals are phenylenediamines, resorcinol and its analogues, ammonium salts and other ammoniacal compounds. These reactions may be classed as irritations or as allergies, the latter being mediated by way of the immune system, as is the case with classic Type IN Delayed Hypersensitivity reactions. In some cases, these adverse reactions can be very severe and prolonged. Therefore, most manufacturers of hair dye products strongly recommend that a skin sensitivity test be carried out, between twenty- four and forty-eight hours before the dye is applied to the hair and scalp. (This delay ensures that any Type IN Delayed Hypersensitivity reactions have time to develop, as well as immediate irritant reactions).

The standard sensitivity test comprises smearing a little of the dye product behind the ear or in the crook of the elbow, where the skin is generally most sensitive. The area of application is examined some hours later for signs of irritation/inflammation. Any such signs are an indication that the particular dye product being tested should not be applied to the user's hair and scalp, as the user is deemed "sensitive" to the product. It is recommended that tests of this type be carried out every time a hair dye product is used, either in the home or at a hairdressing salon or the like, because allergic reactions to hair dye components have been known to develop suddenly following previously trouble-free use.

At present, many salons do not routinely test every client, because such testing is generally unpopular, usually requiring a client to visit the salon twice. It is also a potentially messy procedure. Thus, many users of hair dye products proceed directly to a full application, despite the risk of severe adverse reactions. There are, as a result, believed to be proposals that some form of preliminary testing should become a legal obligation.

Additionally, home-use hair dye kits are widely available, and will carry instructions for pre- use testing. However, given the inconvenience of the standard sensitivity test, it is suspected that it is widely ignored in practice.

Permanent hair dye products account for about 80% of the hair colouring market. These dye products are usually supplied as a two-component system. One component is generally referred to as a "colourant" and the other comprises an oxidiser, also referred to as an "activator" or a "developer". These components may be provided as liquids or gels. The colourant generally comprises an aromatic amine compound (sometimes called the primary intermediate), such as paraphenylenediamine. The colourant usually further comprises a second aromatic compound, called a coupler or a colour modifier, such as resorcinol. The oxidiser usually comprises hydrogen peroxide as its principal chemical oxidant, but other oxidants have been used instead.

The permanent dyeing process involves mixing the colourant and the oxidiser, either in situ on the scalp and hair, or immediately prior to application of the mixed components. The hair dyeing process then proceeds in a series of steps: diffusion of the component chemicals into the hair; oxidation of the primary intermediate by the oxidant; reaction of the oxidised primary intermediate with the coupler; and oxidation of the primary intermediate-coupler addύct into the coloured product. Hence, not only are the initial component reagents present on the scalp, but also various reactive intermediate species, any one of which might be the trigger for a hypersensitive allergic reaction or the like.

Test systems have been proposed in which test patches containing various dye components are applied to the skin for, say, forty-eight hours, then removed to see if an adverse reaction has occurred. While these are less messy than the standard test, they appear not to have achieved widespread adoption. It is believed that they may not sufficiently mimic the processes occurring when a hair dye composition is applied, and so may not be giving an accurate warning in all cases.

It is hence an object of the present invention to provide a means and method for testing skin sensitivity to chemical compositions, and in particular to hair colouring compositions, that obviates the above disadvantages and provides a more convenient and accurate assessment of whether an individual should avoid contact with a particular composition.

According to a first embodiment of the present invention, there is provided a skin sensitivity test patch comprising reservoir means for a fluid test material, a first skin contact surface of the reservoir means which is permeable to the test material, and a second, outer surface generally opposite to the first, wherein said outer surface is adapted to allow at least some of the test material to be passed therethrough into the reservoir means.

Preferably, the test patch is detachably mountable to an area of skin to be tested.

Advantageously, the test patch is provided with adhesive skin mounting means.

The skin contact surface of the test patch may comprise said adhesive means.

Preferably, the skin contact surface of the patch is provided with impermeable barrier layer means, removable before application to the skin.

Preferably, the outer surface of the patch comprises a layer of material through which the test material may pass to the reservoir means.

Said passage layer may be so microscopically porous that the test material may permeate

therethrough.

Alternatively or additionally, the passage layer may be apertured or perforated. Advantageously, said passage layer may be provided with impermeable barrier layer means, removable to provide access thereto.

Optionally, said impermeable barrier layer means is replaceably removable.

In a preferred embodiment, the reservoir means contains a first component of a multiple- component composition.

A second component of the multiple-component composition may then be passed through the outer surface into the reservoir means so as to mix with the first component therein.

In an alternative embodiment, the reservoir means is supplied without test material present, such that each component of a multiple-component composition may be passed through the outer surface into the reservoir means so as to mix therein.

The multiple component composition may be a multiple-component reactive composition.

The multiple-component composition may comprise a hair treatment composition, such as a hair colouring composition.

The test patch may be at least partially transparent or translucent, such that the condition of the area of skin to which it is applied may be monitored. According to a second aspect of the present invention, there is provided a skin sensitivity test kit comprising a skin sensitivity test patch as described in the first aspect above and container means holding a predetermined dose of a second component of a multiple-component reactive composition.

Preferably, the reservoir means of the test patch contains a predetermined dose of a first component of the multiple-component composition.

Alternatively, the kit further comprises container means holding a predetermined dose of said first component.

Advantageously, the kit comprises respective applicator means for the or each component that is held in container means.

Said applicator means may comprise pipette or dropper means.

Alternatively, said applicator means may comprise swab or spatula means.

Said multiple-component composition preferably comprises a hair treatment composition, such as a hair colouring composition.

According to a third aspect of the present invention, there is provided a method for assessing skin sensitivity to a test material comprising the steps of providing a test patch as described in the first aspect above, adding a test material or a second component thereof to the test patch through its outer surface, applying the test patch to an area of skin to be tested, leaving it in place for at least a preselected period and assessing the area of skin for resultant inflammation, irritation or other indications of harmful effects.

Preferably, the test patch is provided with a first component of the test material present therein.

Alternatively, the method may comprise the further step of adding the first component of the test material to the test patch through its outer surface.

The step or steps of adding the test material or components thereof to the test patch may optionally precede the step of applying the test patch to the skin.

Alternatively, the or at least one said addition step may be carried out following the step of applying the test patch to the skin.

The method may comprise the step of providing a test patch through which the skin to which it is applied is visible, and carrying out an initial said assessment step with the test patch still in place.

Embodiments of the present invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which:

Figure 1 is a schematic cross-section of a first test patch embodying the present invention; Figure 2 is a perspective view of a second test patch embodying the present invention; and Figure 3 is a plan view from above of a third test patch embodying the present invention.

Referring now to the Figures and to Figure 1 in particular, a first test patch 1 comprises five layers 2, 3, 4, 5, 6. A top, in use, layer 2 comprises a removable release paper, which protects adjacent layers 3, 4 during storage of the test patch 1. A second layer 3 is substantially porous, so as to allow passage of liquids therethrough. The porous second layer 3 may be microscopically porous, allowing liquid to permeate therethrough, or may be macroscopically apertured or perforated. A third layer 4 is impregnated with a particular hair dye system component (here a colourant composition) which may possibly be an allergen or an irritant. A fourth layer 5 comprises an adhesive, and is protected in storage by a peelable protective fifth layer 6. The fifth layer 6 is removable so that the adhesive layer 5 may be used to stick the test patch 1 detachably to a selected portion of a subject's skin 7.

In use, this particular test patch 1 is stuck to the skin 7 as described, and is then left for a short time to allow some of the liquid colourant composition to diffuse from the third layer 4 to the skin 7. The adhesive layer 5 either comprises adhesive permeable to the colourant and other dye components or is interrupted to allow their passage. This part of the test will detect any rapid, acute sensitivity to the component(s) of the colourant composition.

The top layer 2 is then removed, and a dose of oxidiser is applied on to the porous second layer 3, as shown by arrow- 8. The oxidiser may be transferred from a stock bottle, etc, using a dropper or the like, but preferably a suitably-sized dose may be provided, separately packaged in a vial or a capsule and applied directly or with a swab or a dropper (this may be supplied with the patch 1 and the vial, etc, as a kit). The oxidiser flows through the second layer 3 into the third layer 4, where it mixes and reacts with the colourant composition. This reaction mixture will pass through the adhesive layer 5 to the user's skin 7.

Thus, the subject's skin 7 will be exposed to: (a) unreacted colourant composition; (b) unreacted oxidiser; (c) reactive intermediate species produced during the reaction of (a) and (b); and (d) final products of the reaction between (a) and (b) - i.e. the hair dye-stuffs themselves and any by-products. Any of these materials might possibly cause acute irritation or a delayed onset allergic response to the particular subject being tested.

The test patch 1 is left in place on the skin 7 for at least twenty-four hours, preferably at least forty-eight hours and ideally up to seventy-two hours, before being removed. Any sign of skin inflammation below or adjacent the test patch 1 should be taken as a warning that the subject may well be sensitive to a component or components of the particular dye system in question, or else to some intermediate or reaction product formed during application of the dye system. The subject should not in such an event proceed to use that particular hair dye system on her hair and scalp.

Clearly, if she then wishes to try an alternative dye system, the above testing procedure should be repeated using the appropriate respective colourant and oxidiser components.

The test patch 1 may be used as described above by hairdressing professionals, e.g. at a salon, or by the subject herself. In the latter case, a kit comprising the test patch 1, a dose of oxidiser and an applicator could be given or posted to the subject by a salon when an appointment for a hair-dye application is made, and the subject will then administer the test at an appropriate time before the appointment. The test patch 1 may be left on until the appointment, for the hairdresser to assess the test results, or may be checked by the subject, who will contact the salon if any problems are experienced.

For hair dye systems to be applied at home, the test patch 1 could, for example, be attached to a bottle of one of the dye components, perhaps by shrink-wrapping or by secreting it in a cap of the bottle. The subject would then administer the test herself at the appropriate time prior to applying the hair dye. Instructions and/or contact details could be provided with the test patch 1 , for use if an adverse reaction is detected.

In some embodiments of the test, the test patch 1 may be provided without a colourant or other dye component having first been impregnated into its third layer 4. In this case, as a first step, the top layer 2 is removed and a dose of colourant or the like is added to the porous second layer 3 so as to "load" the third layer 4, soon before or after the test patch 1 is stuck to the skin 7. This allows the test patch 1 to be used with any selected hair dye system, instead of being pre-loaded by a manufacturer with its particular dye component. One thus has a choice between this increased flexibility of use and (probably) superior accuracy of dosing for factory-loaded test patches 1.

A second test patch 9 is shown in Figure 2. This has a structure similar to that of a sticking plaster, with a peripheral zone 10 provided with adhesive and a central pad 11 which here comprises layers corresponding to the top layer 2, second porous layer 3 and third, impregnated layer 4 of the first test patch 1. A peelable protective layer (not visible) extends across an underside of both the peripheral adhesive zone 10 and the central pad 11. In this particular test patch 9, which is otherwise used in the same manner as the first 1, the removable top layer 2 actually comprises a replaceably removable top surface 12 of the central pad 11. It may for example comprise a flap that may be opened to add a dose of oxidiser (and optionally to load an initial dose of colourant into a test patch 9 supplied unloaded), and then replaced to protect the porous layer 3 and to prevent adventitious material (including soap and water) entering the test patch 9 while it is in position on the skin

7.

A third test patch 13 is shown in Figure 3. In this case, the intermediate layers 2, 3, 4 are far thinner than in the second test patch 9, and the entire patch 13 takes the form of a waterslide transfer, such as may be used for temporary tattoos. Informative or decorative indicia 14 may be provided if desired. There is an adhesive layer 5 protected until we by a peelable protective layer 6. After application to the skin, the outermost layer 2 may be debonded on wetting.

This embodiment is easier to conceal or disguise than the second, "sticking plaster" test patch 9. It is also easier to make clear, or at least translucent, so that initial signs of erythema can be spotted and the test halted, if desired, rather than waiting for the test to proceed to its scheduled end, possibly resulting in significant inflamed areas of skin.

For all the test patches 1, 9, 13 it is preferable that at least the porous layer 3 is at least partially translucent, so that one may confirm, by observing the colour change produced, that the colourant and oxidiser are reacting as expected within the third layer 4. In every case, the test patches 1, 9, 13 and methods described have significant advantages over existing devices and methods. Not only is the subject's skin tested for sensitivity to unreacted colourant, oxidiser and other dye components, or for sensitivity to the final dyestuff produced, but also to the entire dynamic chemistry of the dyeing process,- including reactive, transient intermediates which may well cause skin problems that the starting reagents or final products do not. It is also straightforward to tailor a test method to the particular dye formulation that the subject is proposing to apply, using the correct concentrations of major components and complete with any minor components present in the formulation.

While it may not identify the exact chemical species to which the subject is sensitive, this is not immediately important - the subject simply needs to know that she should avoid the entire dye formulation in question. Exact identification of the offending material, if desired, should in any case be carried out by qualified medical personnel using standard dermatological techniques.

Note: while this description is phrased in terms of a female user of hair colouring products, it is equally applicable to male users, and "she" should be understood to include "he" and so forth.

Claims

1. A skin sensitivity test patch comprising reservoir means for a fluid test material, a first skin contact surface of the reservoir means which is permeable to the test material, and a second, outer surface generally opposite to the first, wherein said outer surface is adapted to allow at least some of the test material to be passed therethrough into the reservoir means.

2. A test patch as claimed in claim 1, further comprising means to allow its detachable mounting to an area of skin to be tested.

3. A test patch as claimed in either claim 1 or claim 2, wherein the skin contact surface of the patch is provided with impermeable barrier layer means, removable before application to the skin.

4. A test patch as claimed in any one of the preceding claims, wherein the outer surface of the patch comprises a layer of microporous, apertured or perforated material through which test material may pass into the reservoir means.

5. A test patch as claimed in claim 4, wherein said passage layer is provided with impermeable barrier layer means, removable to provide access thereto, optionally replaceably removable.

6. A test patch as claimed in any one of the preceding claims, wherein the reservoir means is supplied initially without test material present.

7. A test patch as claimed in any one of claims 1 to 5, wherein the reservoir means contains a first component of a multiple-component test material composition.

8. A test patch as claimed in claim 7, wherein the multiple-component composition comprises a hair treatment cosmetic composition, such as a hair colouring composition.

9. A test patch as claimed in any one of the preceding claims that is at least partially transparent or translucent, such that the condition of he area of skin to which it is applied may be monitored.

10. A skin sensitivity test kit comprising a skin sensitivity test patch as claimed in any one of the preceding claims and container means holding a predetermined dose of a second component of a multiple-component reactive composition.

11. A test kit as claimed in claim 10, wherein the reservoir means of the test patch contains a predetermined dose of a first component of the multiple-component composition.

12. A test kit as claimed in claim 10, further comprising container means holding a predetermined dose of said first component.

13. A test kit as claimed in any one of claims 10 to 12, wherein said multiple-component composition comprises a hair treatment composition, such as a hair colouring composition.

14. A method for assessing skin sensitivity to a cosmetic test material comprising the steps of providing a test patch as claimed in any one of claims 1 to 9, adding a test material or a second component thereof to the test patch, applying the test patch to an area of skin to be tested, leaving it in place for a predetermined period and assessing the area of skin for resultant inflammation, irritation or other indications of harmful effects.

15. A method as claimed in claim 14, wherein the test patch is provided with a first component of the test material contained therein.

16. A method as claimed in claim 14, comprising the further step of adding the first component of the test material to the test patch through its outer surface.

17. A method as claimed in any one of claims 14 to 16, wherein the step or steps of adding the test material or components thereof to the test patch precede the step of applying the test patch to the skin.

18. A method as claimed in any one of claims 14 to 16, wherein the or at least one said addition step is carried out following the step of applying the test patch to the skin.