GB2564762A

GB2564762A - Wound dressing

Info

Publication number: GB2564762A
Application number: GB1808841.9A
Authority: GB
Inventors: Murandu Moses
Original assignee: Of Wolverhampton Science Park Ltd, University of
Current assignee: Of Wolverhampton Science Park Ltd, University of
Priority date: 2017-05-30
Filing date: 2018-05-30
Publication date: 2019-01-23
Also published as: GB201708579D0; GB201808841D0

Abstract

A wound dressing 10 comprising a first skin contacting layer 16 formed from a flexible and liquid permeable or semi-permeable material, and an opposing second layer 18 formed from a flexible and liquid-absorbent material. In use both layers 16, 18 are at least partially sealed or joined together with a layer of granulated sugar 20 provided therebetween. In one arrangement the dressing 10 is provided as a pouch with only the peripheral edges 14 of the layers 16, 18 sealed together to define a cavity 22 therebetween, with the granulated sugar 20 provided within the cavity 22. In another arrangement both layers (16, 18; Fig 3) are placed in opposition and secured together across their entire extent by means of an adhesive. In this arrangement the sugar may be dispersed through the adhesive, which may be provided as spun sugar. Alternatively the sugar may be impregnated within apertures formed in the first layer (16, Fig 3), which is provided as a mesh in this arrangement.

Description

WOUND DRESSING

Field of the Invention

This invention relates generally to a wound dressing and to a method of manufacturing a wound dressing, such a wound dressing being more particularly, although not necessarily exclusively, suitable for the management and/or treatment of sloughy or necrotic wounds, such as ulcers, in the human or animal body.

Background of the Invention

A skin ulcer is an open sore that can develop when the skin is broken and air or bacteria gets into the underlying tissues. They can, for example, develop as a result of a minor injury or underlying condition or disease. Irrespective of the cause of skin ulcers, once they are established, they can be very difficult to treat effectively and can, in many cases, persist for months or even years. This is because such ulcers typically become infected with bacteria and, once infected, the skin and flesh break down further, leading to more infection. Because the bacteria live in a thin, slimy film on the surface of the wound which is outside the body, conventional oral or intravenous antibiotics are usually not suitable for effective treatment. Instead, regular wound cleaning, anti-inflammatory treatment and the application of dressings have typically been used to manage and treat such ulcers. Nevertheless, conventional treatments have varying degrees of effectiveness, and ongoing and persistent skin ulcers are not only relatively common, but they can have a devastating effect on the quality of life of the sufferer.

More recently, it has been proposed to use granulated sugar in the treatment of sloughy or necrotic wounds such as ulcers of the above-described type. The treatment process involves a layering application process, whereby a layer comprising a certain amount of sugar is applied to a wound, followed by one or more dressing layers, followed by a bandage or similar means to retain the treatment layers in the correct position in or on the wound. This treatment must be repeated, and the dressings replaced, regularly, as with more conventional treatments.

There are a few issues and drawbacks associated with this treatment process, in its current form. Firstly, it must be performed by a qualified, trained and experienced practitioner, who not only has access to medical/surgical grade sugar, but is also able to maintain that medical/surgical grade certification because they have access to the correct storage and practice environments. There is an adequate or even optimum quantity of sugar that should be applied to wound, depending on its size, and the practitioner needs to be sufficiently skilled and experienced to know what that quantity is in any given case. Similarly, the thickness of the sugar layer needs to be correct, and the remaining dressing and bandaging steps must be performed adequately to ensure that the treatment is applied and retained for optimum effectiveness. Furthermore, where a treatment process needs to be repeated daily, or even multiple times during each day, this requirement can place a large burden on professional health resources and may, in any event, not even be possible, at least in some parts of the world. Secondly, the treatment process requires the use of medical/surgical grade granulated sugar, to ensure sterility, and this may not be generally available, or even available at all in some parts of the world; and even if it is available, maintaining that medical/surgical grade certification poses a further problem.

It is, therefore, an object of aspects of the present invention to provide an integrated wound dressing particularly, although not necessarily exclusively, suitable for the management and/or treatment of sloughy or necrotic wounds, such as ulcers, that addresses these issues. It is another object of aspects of the present invention to provide a method of manufacturing such an integrated wound dressing.

Summary of the Invention

Thus, in accordance with the present invention, there is provided a wound dressing comprising a pouch or pad including first and second layers of flexible material, each having first and second surfaces, the respective first surfaces of each of the first and second layers being sealed or joined together,wherein a layer of granulated sugar is contained between said first surfaces of said first and second layers, and wherein said first layer is formed of a material that becomes substantially liquid permeable upon contact with liquid, in use, and said second layer is formed of a liquidabsorbent material.

In an exemplary embodiment, the first surfaces of said first and second layers may be sealed, at or adjacent their peripheral edges, to define an internal cavity therebetween, wherein said layer of granulated sugar is contained within said cavity.

In practice, the first layer may be formed of a semi-permeable, permeable or soluble material. In a first exemplary embodiment, the first layer may be formed of a paperlike sheet formed of organic material (e.g. seaweed) that dissolves or becomes permeable through contact with liquid. In an alternative exemplary embodiment, the first layer may be formed of a mesh-like material, such as semi-permeable gauze material. However, if the first layer is not already liquid permeable, should be configured to dissolve, or become liquid permeable, upon (or shortly after) contact with the liquid in a wound, in use.

In another exemplary embodiment, the first surfaces of the first and second layers may be held together by a soluble adhesive, such as spun sugar, and the layer of granulated sugar may be dispersed through the adhesive or individual grains may be impregnated in the holes in a gauze-like tissue material, for example. In one specific exemplary embodiment, the first “layer” may, in fact, comprise multiple layers,. Each carrying, or having impregnated therein, a layer or a portion of a layer, of granulated sugar. Whilst the layers may be bonded together by a soluble adhesive, additional through-stitching may be used to hold the layers firmly together. The benefit of these latter embodiments may be that a large sheet of the wound dressing may be provided, that can be cut to size, without losing much of the granulated sugar (which is held by the soluble adhesive).

Optionally, the second layer may be formed of a non-woven fabric, such as non woven polyester material. The significant advantage of the second (liquidabsorbent) layer is that it actually soaks up the high concentration sugar solution created by the liquid from the wound and the layer of granulated sugar when outer surface of the first layer contacts the wound and becomes liquid permeable or dissolves altogether. There is no need for any additional liquid to achieve the desired effect. Because the second layer absorbs that liquid as it is created against the wound, the patient’s bedding does not become soiled and the dressing is prevented from sticking to the wound, such that any discomfort that might arise when changing the dressing is minimised.

In an exemplary embodiment, said first and second layers may be heat sealed at or adjacent their peripheral edges to define said internal cavity therebetween, although alternative sealing means (e.g. adhesive) may be used.

The first and second layers may be sealed at or adjacent their peripheral edges at a tension sufficient to configure said pouch as a pad and retain said granulated sugar in said cavity as a substantially uniform layer across the inner surface thereof.

The cavity may be compartmentalised by means of one or more intermediate seals between said first and second layers, each of a plurality of compartments thereof containing a quantity of said granulated sugar.id first and second layers

The wound dressing may, advantageously, further comprise means for retaining said pouch on a body part of a patient, in use, with said first layer immediately adjacent the patient’s skin. Such means for retaining said pouch may, for example, comprise an integrated bandage member, or a layer of adhesive at or adjacent said first layer. In the latter case, the second layer may have an area greater than that of said first layer, said first layer is located generally centrally on said second layer so that a peripheral edge region of said second layer extends around the peripheral edges of said first layer, and wherein said layer of adhesive is provided on said peripheral edge region of said second layer. A removable backing sheet may be provided over said layer of adhesive and/or an outer surface of said first layer.

In an exemplary embodiment, the wound dressing may advantageously comprise a layer of water resistant or waterproof material over an outer surface of said second layer.

The dimensions of the pouch and, therefore, the quantity of granulated sugar contained within said cavity is beneficially sufficient to create, in use, a sugar concentration in a patient’s wound of between 0.38 and 25%.

Purely by way of example, the dimensions of said first layer (and, therefore, the operable area of the pouch) may be 10 x 10cm and the quantity of granulated sugar contained within said cavity may be substantially 30g; or the dimensions of said first layer (and, therefore, the dimensions of the operable area of the pouch) may be 15 x 20cm and the quantity of sugar contained within said cavity may be substantially 60g.

In accordance with another aspects of the present invention, there is provided a method of manufacturing a wound dressing according to any of the preceding claims comprising providing a first layer of semi-permeable, permeable or soluble material, providing a second layer of liquid-absorbent material, applying an intermediate layer of granulated sugar on said first layer, placing first respective surfaces of said first and second layers in opposition and sealing said first layer to said second layer at or adjacent the edges of said intermediate layer to form a sealed pouch defining a cavity therebetween and containing said granulated sugar.

The method may comprise selecting an area of said intermediate layer of granulated to sugar that will create, in use in or on a sloughy or necrotic wound, a sugar concentration in said wound of between 0.38 - 25%.

The granulated sugar is preferably medical/surgical grade sugar and may, optionally, comprise granulated beet sugar or granulated cane sugar.

The outer surface of the first layer may, optionally (and for some applications), include a ‘sticky’ layer of adhesive. This may, for example, comprise spun sugar or other adhesive that dissolves (or becomes less “sticky) on contact with liquid, so as to hold the dressing in place when first applied but avoiding it actually sticking to the wound in use.

Description ofthe Drawings

These and other aspects of the present invention will be apparent from the following detailed description, in which an exemplary embodiment ofthe invention is described, by way of example only, and with reference to the accompanying drawings, in which:

Figure 1A is a plan view of a wound dressing according to an exemplary embodiment of the present invention;

Figure 1B is a schematic bottom view of a wound dressing according to an exemplary embodiment of the present invention, with the backing sheet omitted;

Figure 1C is a schematic cross-sectional view of a wound dressing according to an exemplary embodiment ofthe present invention; and

Figure 2 is a schematic flow diagram illustrating some of the principal steps of a method of manufacturing a wound dressing according to an exemplary embodiment of the present.

Detailed Description

Referring to Figures 1A, 1B and 1C ofthe drawings, a wound dressing 10 according to an exemplary embodiment of the present invention comprises a generally rectangular or square pad consisting of a generally central flexible pad region 12 and a flexible peripheral or edge region 14 surrounding the pad region 12. The pad region 12 may be of any convenient/suitable size, and selected according to the size and/or type of wound to be treated. Examples of pad region sizes in conventional wound dressing pads include 10cm x 10cm (square) and 15cm x 20cm (rectangular) and these approximate dimensions are equally applicable to the pad region 12 ofthe present invention, but it is to be understood that the pad region of a wound dressing of the present invention can have any suitable dimensions (and is advantageously supplied in a range of such dimensions for selection according to the size/type of wound to be treated), and the invention is not necessarily intended to be limited in this regard.

The pad region 12 is of a layered construction comprising a first layer 16, intended to be placed in contact with a wound area, in use, an opposing second layer 18, and an intermediate layer 20 located between the first and second layers 16, 18. Indeed, the pad region 12 is, in fact, in the form of a flexible sealed pouch comprising the first and second layers 16, 18, with their respective surfaces (on one side) placed in opposition and sealed together at or adjacent their peripheral edges to form a sealed pouch defining a cavity 22 therein. During manufacture, and prior to sealing the edges of the pouch, a quantity of granulated sugar is placed between the opposing surfaces of the first and second layers 16, 18, to form the intermediate layer 20 of granulated sugar that is contained and retained within the cavity 22. An exemplary method of manufacture will be described hereinafter.

The first layer 16, which is placed in or on a wound to be treated, in use, must be of a material that allows liquid from the wound to seep into the cavity 22 and contact the layer 20 of granulated sugar and thus, subsequently, allows the liquid/sugar mixture to exude through that layer 16 onto or into the wound. In a first exemplary embodiment, the first layer 16 may be formed of a material that dissolves on contact with liquid, or at least becomes liquid-permeable as a consequence of such contact. For example, a known, paper-like sheet formed of organic material (e.g. seaweed) may be utilised for this purpose. In this case, the first layer 16 would be substantially impermeable before use, and then dissolve on contact with the liquids in the wound, once applied thereto, to allow such liquids to contact and mix with the granulated sugar layer 20 in direct contact with the wound. In an alternative exemplary embodiment, the first layer 16 may comprise a layer of semi-permeable material, such as a mesh-like material, e.g. gauze. In this case, when the first layer 16 comes into contact with a wound, in use, the liquids therefrom enter the cavity 22, mix with the granulated sugar layer 20, and the resultant liquefied mixture exudes from the cavity 22, through the first layer 16, back into the wound.

The second layer 18 is formed of an absorbent material, such as the non-woven polyester material used in some conventional dressing pads. It can be seen in Figures 1 A, 1B and 1C that the peripheral edges of the first layer 16 are sealed against the surface of the second layer 18 at a location inward of the peripheral edges thereof so as to form a generally central pouch (or ‘pad region 12’) having a narrow edge region 14 formed by the ‘free’ peripheral edge region of the second layer. The pouch, thus formed, defines the above-mentioned sealed cavity 22 therein containing the intermediate layer 20 of granulated sugar.

The granulated sugar suitable for use in the present invention may be of any known type (e.g. demerara, granulated beet sugar, granulated cane sugar, etc) and the present invention is not necessarily intended to be limited in this regard, although it is though that granulated beet sugar and granulated cane sugar may yield the best results in terms of their effectiveness in inhibiting bacterial growth. The granulated sugar should, however (and if possible) be certified as medical/surgical grade (i.e. processed and packaged in a suitably sterile environment and under suitably sterile conditions).

The quantity of sugar forming the intermediate layer 20 will be dependent on the size of the pad region 12 and selected to provide a defined concentration of sugar (or a concentration of sugar within a defined range) within a wound of a certain size. A suitable concentration of sugar to provide adequate minimum inhibitory concentration (MIC) against Gram-negative and Gram-positive bacteria, and inhibit growth of Staphylococcus aureus, Escherichia coli and Pseudonomas aeruginosa, is though to be 0.38 - 25%, although the present invention is not necessarily intended to be limited in this regard.

The sugar within the cavity 22 needs to be retained and maintained in a fairly uniform layer across the inner surface of the first layer 16, irrespective of the relative orientation of the wound dressing (such that the concentration of sugar across the wound is fairly uniform). This may be achieved in a number of different ways. For example, the first and second layers 16, 18 may be sealed together under tension (i.e. stretched a little) so that they are naturally biased toward each other (thereby limiting the ‘height’ of the cavity to about the thickness of the desired layer of sugar) and act to retain and maintain the layer 20 as applied therein. Additionally, or alternatively, air may be removed from the cavity 22 before or after the sugar layer 20 is applied therein and prior to sealing the pouch. Of course, and depending on the materials used to form (or cover) the first and second layers 16, 18, this may not actually create a vacuum but should be sufficient to retain and maintain the sugar layer 20 as required. In yet another exemplary embodiment, the layer of sugar may be applied to the inner surface of the first layer 16 (i.e. its surface within the cavity 22) by means of an organic adhesive that acts to retain the sugar in layer form prior to use, and dissolves upon contact with liquid. Other options for achieving the desired layer of sugar, and retaining and maintaining it as required, may be apparent to a person skilled in the art. For example, the pouch may include intermediate seals to define two or more compartments, each containing a smaller quantity of sugar within a smaller defined area of the pad region 12, such that the sugar in all of the compartments together forms the desired layer 20. Another option might be to apply the sugar, during manufacturing of the wound dressing, in the form of a single-dose wrapped package placed on the inner surface of the first layer 16 before creating the pouch around it, wherein that package is shaped and configured with the dimensions of the sugar layer and is formed of a material that dissolves upon contact with liquid.

The edge region 14 may have thereon a layer 26 of adhesive, on the surface corresponding to the outer surface of the first layer 16 (i.e. the surface intended to contact the wound) such that the dressing, once applied to the wound, is retained in position by the adhesive layer which adheres to the patient’s skin around the wound being treated. A removable backing sheet 24, of dimensions similar to those of the second layer 18, may be provided over the outer surface of the first layer 16 and adhered thereto via the adhesive layer 26, such that removal of the backing sheet, when the wound dressing is required for use, exposes the outer surface of the first layer 16 and the adhesive layer 26.

A layer 28 or coating of water resistant or waterproof material (e.g. polyurethane) may be provided over the outer surface of the second layer 18; and the wound dressing 10 in its entirety may be supplied in a sterile, sealed package, that should be easily removable when the dressing is required for use.

An exemplary method of manufacturing a wound dressing according to an exemplary embodiment of the present invention will now be described in more detail, with reference to Figure 2 of the drawings. A typical automatic or semi-automatic production apparatus suitable for this manufacturing process may comprise one or more feeding devices, cutting device(s), and a heat sealing device, optionally linked together by an automatic transfer system, and incorporating, at a convenient point in the production line, a device for applying the sugar layer 20 (prior to heat sealing).

Thus, and referring additionally to Figure 2 of the drawings, the method of manufacture, which may be fed with a roll of the material for the second layer 18 and a roll of the material for the first layer 16, may start with feeding the material for the first layer 16 to a sugar application station (step 100), where a layer of sugar is applied in spaced apart layer regions as the material is fed therethrough (step 102). This element of the process will be described in more detail hereinafter.

Next, at step 104, the material for the second layer 18, which may include thereon a layer of waterproof or water resistant material, is fed parallel to the material of the first layer 16 carrying the layers of sugar thereon, and the two layers together are fed to a heat sealing device. At step 106, the heat sealing device creates a seal, joining the first and second layers, around the region in which each layer of sugar is deposited. Next, the joined materials are fed to a cutting device, and cut between each adjacent seal in, leaving an edge portion of the material of the second layer around each “pouch” containing the sugar layer (step 108). Each dressing, thus formed, is then transferred to an adhesive station, where a layer of adhesive is applied to the edge portion and a backing sheet is applied over the outer surface of the first layer 16 and the layer of adhesive (step 110). Finally, the wound dressing is transferred to a packaging station for packing in a sterile package for transport and storage.

Each pouch formed between the sealed first and second layers and containing the granulated sugar is of a selected size and shape. Typically, it will be generally square or rectangular, but the dimensions will vary according to the size of dressing being manufactured, and the dimensions of the pouch will determine the quantity of sugar to be contained therein. The pouch may, for example, be 10 x 10cm or 15 x 20 cm, similar to the dimensions of a conventional wound dressing. In order to achieve the desired sugar concentration in a wound, during use, the quantity of sugar for the 10x10cm pouch might be around 30g and the quantity of sugar for a 15 x 20cm pouch might be 60g to achieve a sugar concentration, in use, within a range 0.38 - 25%. However, the present invention is not necessarily intended to be limited in this regard.

As explained above, the granulated sugar, which may be of any known type, should ideally be of medical/surgical grade (i.e. processed and packaged in a sterile environment and under sterile conditions, and certified as such) and it is desirable that such certification would be retained and maintained throughout the subsequent manufacturing process for the wound dressing. Thus, if the sugar is obtained from an external source, the manufacturing process should, ideally, incorporate means that ensure that the medical/surgical grade certification of the sugar in the dressings is retained or can be re-issued.

The sugar may be applied to the first layer material in loose form from a storage hopper via a chute. A dispenser may be employed to dispense sugar and a sensor may be used to weigh the sugar as it is dispensed to obtain a quantity thereof that is equal to one “portion”, before applying it, via the chute, to the first layer. Alternatively, the sugar may be supplied in packets containing individual “portions”, in which case an opening device may be used to open each packet before its contents are dispensed and applied to the first layer material. In any event, and maintain the required sterile conditions, the hopper, chute and surrounding areas and devices (at least) must operate under sterile or ‘clean room’ conditions. In another exemplary embodiment, the sugar may be packaged at source in individual single-dose packages formed of a material that dissolves upon contact with liquid, in which case, these individual packages can be transferred to the first layer by means of, for example, a vacuum suction application device or suitable programmed robotic arm. Other suitable methods of applying each individual portion/layer of granulated sugar to the first layer may be apparent to a person skilled in the art.

In another exemplary embodiment, and referring to Figured 3 of the drawings, a wound dressing 10’ according to the present invention comprises a generally rectangular or square flexible sheet or pad, which may be in provided in a form to be cut to any convenient/suitable size for the type or size of wound to be treated.

The dressing sheet or pad 10’ is of a layered construction comprising a first layer 16’, intended to be placed in contact with a wound area, in use, an opposing second layer 18’, and an intermediate layer 20’ located between the first and second layers 16’, 18’. The pad 10’ comprises first and second layers 16’, 18’, with their respective surfaces (on one side) placed in opposition and adhered together. The adhesive layer 20’ used to join the first and second layers 16’, 18’ together may comprise a liquid soluble adhesive, such as spun sugar for example. During manufacture, in one exemplary embodiment, a quantity of granulated sugar is placed over the inward facing surface of the first layer 16’ (or impregnated into holes therein, in the case of a gauze-like tissue for example) and then the second layer 18’ is adhered over the top of the granulated sugar layer, to the first layer 16’. In another exemplary embodiment, the granulated sugar 19 may be dispersed within the liquid soluble adhesive layer 20’.

As before, the first layer 16’, which is placed in or on a wound to be treated, in use, must be of a material that allows liquid from the wound to seep into the space occupied by the liquid soluble adhesive and contact the granulated sugar, and thus, subsequently, allows the liquid/sugar mixture to exude through that layer 16’ onto or into the wound. In a first exemplary embodiment, the first layer 16’ may be formed of a material that dissolves on contact with liquid, or at least becomes liquid-permeable as a consequence of such contact. For example, a known, paper-like sheet formed of organic material (e.g. seaweed) may be utilised for this purpose. In this case, the first layer 16’ would be substantially impermeable before use, and then dissolve on contact with the liquids in the wound, once applied thereto, to allow such liquids to contact and mix with the granulated sugar layer 20’ in direct contact with the wound. In an alternative exemplary embodiment, the first layer 16’ may comprise a layer of semi-permeable material, such as a mesh-like material, e.g. gauze or a gauze-like tissue material. In this case, when the first layer 16’ comes into contact with a wound, in use, seep into the liquid soluble adhesive (and dissolve it) and, mix with the granulated sugar layer 20’, and the resultant liquefied mixture exudes through the first layer 16’, back into the wound.

The second layer 18’ is formed of a liquid- absorbent material, such as the nonwoven polyester material used in some conventional dressing pads.

As before, the granulated sugar suitable for use in the present invention may be of any known type (e.g. demerara, granulated beet sugar, granulated cane sugar, etc) and the present invention is not necessarily intended to be limited in this regard, although it is though that granulated beet sugar and granulated cane sugar may yield the best results in terms of their effectiveness in inhibiting bacterial growth. The granulated sugar should, however (and if possible) be certified as medical/surgical grade (i.e. processed and packaged in a suitably sterile environment and under suitably sterile conditions).

The quantity of sugar forming the intermediate layer 20’ will, of course, be dependent on the size of the wound dressing, and selected to provide a defined concentration of sugar (or a concentration of sugar within a defined range) within a wound of a certain size. A suitable concentration of sugar to provide adequate minimum inhibitory concentration (MIC) against Gram-negative and Gram-positive bacteria, and inhibit growth of Staphylococcus aureus, Escherichia coli and Pseudonomas aeruginosa, is though to be 0.38 - 25%, although the present invention is not necessarily intended to be limited in this regard.

The sugar between the first and second layers 16’, 18’ needs to be retained and maintained in a fairly uniform layer across the inner surface of the first layer 16’, irrespective of the relative orientation of the wound dressing (such that the concentration of sugar across the wound is fairly uniform). This may be achieved in a number of different ways. For example, the first and second layers 16’, 18’ may be adhered together under tension (i.e. stretched a little) so that they are naturally biased toward each other (thereby limiting the space between the two adjoining surfaces to about the thickness of the desired layer of sugar) and act to retain and maintain the layer 20’ as applied therein. In yet another exemplary embodiment, the layer of sugar may be applied to the inner surface of the first layer 16’ by means of an organic adhesive that acts to retain the sugar in layer form prior to use, and dissolves upon contact with liquid. Other options for achieving the desired layer of sugar, and retaining and maintaining it as required, may be apparent to a person skilled in the art. For example, the pad may include intermediate seals or throughstitching to define two or more compartments, each containing a smaller quantity of sugar, such that the sugar in all of the compartments together forms the desired layer 20’.

The edge region, or even substantially all of, the outer surface of the first layer 16’ (i.e. the surface intended to contact the wound) may have thereon a layer of adhesive, such that the dressing, once applied to the wound, is retained in position by the adhesive layer which adheres to the patient’s skin around the wound being treated. A removable backing sheet (which should be able to be cut with a pair of scissors or the like), of dimensions similar to those of the pad, may be provided over the outer surface of the first layer 16’ and adhered thereto via the above-mentioned adhesive layer, such that removal of the backing sheet, when the wound dressing is required for use, exposes the outer surface of the first layer 16’ and the adhesive layer.

A layer or coating of water resistant or waterproof material (e.g. polyurethane) may be provided over the outer surface of the second layer 18’, as before; and the wound dressing 10’ in its entirety may be supplied in a sterile, sealed package, that should be easily removable when the dressing is required for use.

It will be apparent to a person skilled in the art, from the foregoing description, that modifications and variations can be made to the described embodiments without departing from the scope of the invention as defined by the appended claims.

Claims

1. A wound dressing comprising a pouch or pad including first and second layers of flexible material, each having first and second opposing surfaces, the respective first surfaces of each of the first and second layers being sealed or joined together with a layer of granulated sugar therebetween, wherein said first layer is formed of a material that is liquid permeable or becomes substantially liquid permeable upon contact with liquid, in use, and said second layer is formed of a liquid-absorbent material.

2. A wound dressing according to claim 1, wherein said first and second surfaces of said first and second layers are sealed, at or adjacent their peripheral edges, to define an internal cavity therebetween, and wherein said layer of granulated sugar is contained within said cavity.

3. A wound dressing according to claim 1, wherein said first layer is formed of a paper-like sheet formed of organic material that dissolves or becomes permeable through contact with liquid.

4. A wound dressing according to claim 1, wherein said first layer is formed of a mesh-like material.

5. A wound dressing according to claim 1 or claim 4, wherein said first layer is formed of a semi-permeable gauze material.

6. A wound dressing according to claim 1, wherein the first surfaces of the first and second layers are held together by a soluble adhesive.

7. A wound dressing according to claim 6, wherein said layer of granulated sugar is dispersed through said soluble adhesive.

8. A wound dressing according to claim 7, wherein said soluble adhesive is spun sugar.

9. A wound dressing according to claim 6, wherein said first layer is formed of a tissue material,

10. A wound dressing according to claim 6, wherein said first layer is formed of a mesh-like material, having a series of apertures therein, and wherein said layer of granulated sugar is impregnated into said apertures.

11. A wound dressing according to any of the preceding claims, wherein said second layer is formed of a non-woven fabric.

12. A wound dressing according to claim 11, wherein said second layer is formed of a non-woven polyester material.

13. A wound dressing according to claim 2, wherein said first and second layers are heat sealed at or adjacent their peripheral edges to define said internal cavity therebetween.

14. A wound dressing according to claim 2, wherein said first and second layers are sealed at or adjacent their peripheral edges at a tension sufficient to configure said pouch as a pad and retain said granulated sugar in said cavity as a substantially uniform layer across the inner surface thereof.

15. A wound dressing according to claim 2, wherein said cavity is compartmentalised by means of one or more intermediate seals between said first and second layers, each of a plurality of compartments thereof containing a quantity of said granulated sugar.id first and second layers

16. A wound dressing according to any of the preceding claims, further comprising means for retaining said pad or pouch on a body part of a patient, in use, with said first layer immediately adjacent the patient’s skin.

17. A wound dressing according to claim 16, wherein said means for retaining said pad or pouch comprises an integrated bandage member.

18. A wound dressing according to claim 16, wherein said means for retaining said pad or pouch comprises a layer of adhesive at or adjacent said first layer.

19. A wound dressing according to claim 18, when dependent on claim 2, wherein said second layer has an area greater than that of said first layer, said first layer is located generally centrally on said second layer so that a peripheral edge region of said second layer extends around the peripheral edges of said first layer, and wherein said layer of adhesive is provided on said peripheral edge region of said second layer.

20. A wound dressing according to claim 18 or claim 19, comprising a removable backing sheet over said layer of adhesive and/or an outer surface of said first layer.

21. A wound dressing according to any of the preceding claims, comprising a layer of water resistant or waterproof material over an outer surface of said second layer.

22. A wound dressing according to any of the preceding claims, wherein a quantity of granulated sugar contained between said first and second layers is sufficient to create, in use, a sugar concentration in a patient’s wound of between

0.38 and 25%.

23. A wound dressing according to any of the preceding claims, wherein the dimensions of said first layer are 10 x 10cm and the quantity of granulated sugar contained within said cavity is substantially 30g.

24. A wound dressing according to any of claims 1 to 22, wherein the dimensions of said first layer are 15 x 20cm and the quantity of sugar contained within said cavity is substantially 60g.

25. A method of manufacturing a wound dressing according to any of the preceding claims comprising providing a first layer of liquid permeable or liquid soluble materialproviding a second layer of liquid-absorbent material, applying an intermediate layer of granulated sugar on a first surface of said first or second layer, placing first respective surfaces of said first and second layers in opposition and sealing said first layer to said second layer to form a sealed pad or pouch.

26. A method according to claim 25, comprising selecting an area of said intermediate layer of granulated to sugar that will create, in use in or on a sloughy or necrotic wound, a sugar concentration in said wound of between 0.38 - 25%.

27. A method according to claim 25 or claim 26, wherein said granulated sugar is medical/surgical grade sugar.

28. A method according to any of claims 25 to 27, wherein said granulated sugar comprises granulated beet sugar or granulated cane sugar.