WO2002055113A2

WO2002055113A2 - A hydrogel/hydrocolloid composite

Info

Publication number: WO2002055113A2
Application number: PCT/US2002/000703
Authority: WO
Inventors: Michael Pereira
Original assignee: North American Sterilization & Packaging Company
Priority date: 2001-01-11
Filing date: 2002-01-11
Publication date: 2002-07-18
Also published as: AU2002243505A1; WO2002055113A3

Abstract

The present invetnion relates to a composite structure comprising a hydrocolloid and a hyrogel. In one embodiment, the composite structure comprises an island dressing comprising one layer of a hydrogel and another layer of a hydrocolloid. In yet another embodiment, the hydrocolloid is composed of a meterial that has a swell ratio of about 1% to about 35% (measured by ASTM D 2765-95). In a further embodiment, the composite structure comprosies three layers: (a) a hydrogel; (b) a liner composed of a low moisture vapor transmission rate plastic or composition; and (c) a hydrocolloid having a low swell ratio. In another embodiemnt, the present invention comprises a method of making the composite structure of the present invention.

Description

A HYDROGEL/HYDROCOLLOID COMPOSITE FIELD OF THE INVENTION

The present invention relates to a wound care management system for wound treatment. The wound covering is composed of a composite structure of a hydrocolloid and a hydrogel. In one specific embodiment, the wound covering provides for a moist wound bed and other aspects of the environment at the wound site. BACKGROUND OF THE INVENTION

Conventionally, wound management is typically achieved by placing a gauze pad with an adhesive backing over the wound. Drugs or topical creams may be applied to the skin, and covered by the gauze. These conventional wound management systems may leave the sides of the wounds exposed. In addition, traditional wound coverings such as bandages are used to mechanically close wounds. Such bandages typically cover and touch the wound. Bandage contact with the wound may interfere with the healing process and the adhesive from the bandage may cause irritation and rash. SUMMARY OF THE INVENTION

The present invention relates to a composite structure comprising a hydrocolloid and a hydrogel. In one embodiment, the composite structure comprises an island dressing comprising one layer of a hydrogel and another layer of a hydrocolloid. In yet another embodiment, the hydrocolloid is composed of a material that has a swell ratio of about 1% to about 35 % (measured by ASTM D 2765-95). In a further embodiment, the composite structure comprises three layers: (a) a hydrogel; (b) a liner composed of a low moisture vapor transmission rate plastic or composition; and (c) a hydrocolloid having a low swell ratio. In another embodiment, the present invention comprises a method of making the composite structure of the present invention. BRIEF DESCRIPTION OF THE DRAWING

Fig. 1 is an illustrative plan view of one embodiment of the present invention.

Fig. 2 is an illustrative expanded cross-section view of another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

The present invention comprises a composite structure of a hydrogel (also referred to in the industry as "hydrophilic gel") and a hydrocolloid. In one embodiment, for a wound care, the hydrogel and hydrocolloid composite forms a wound care management system. The hydrogel forms the center part of the system and covers the wound. The hydrogel may assist in accelerating the wound healing process while providing a moist atmosphere. The hydrocolloid is affixed to the hydrogel and adheres to the desired body part. For purposes of the present invention, this construction will be referred to as an "island dressing." Consequently, the wound care management system incorporates both the high water content (e.g. about 20 to about 98 wt. % of total) of the hydrogel to achieve moist healing and the high solids content of the hydrocolloid (e.g. about 60 to about 100 wt. % of total solids) to maximize adhesion to the skin. In addition, the wound care management system forms an occlusive seal around the wound, while providing a moist healing bed for the wound area that assists in accelerating the wound healing process.

In one embodiment of a hydrogel suitable for the present invention, the hydrogel may be composed of one of two types of base polymers or mixtures thereof. The first polymer base is polyethylene oxide (e.g. sold as "Polyox" by Union Carbide). Polyethylene oxide is typically categorized by its specific molecular weight ("MW") and suitable molecular weights include, but are not limited to, the range of about 100,000 to about 8,000,000. For example, suitable "Polyox" products include: POLYOX WSR Coagulant (5,000,000 MW); POLYOX WSR 301 (4,000,000 MW); POLYOX WSR 303 (7,000,000 MW); POLYOX WSR 308 (8,000,000 MW); POLYOX WSR -10 (100,000 MW); POLYOX 1105 (900,000 MW); POLYOX -12K (1,000,000 MW); POLYOX WSR 205 (600,000 MW); POLYOX -3000 (400,000 MW); POLYOX 60K (2,000,000 MW); POLYOX WSR 750 (300,000 MW); POLYOX WSR -80 (200,000 MW) . The second polymer base is polyvinylpyrrolidone. Polyvinylpyrrolidone is typically categorized by its specific molecular weight and suitable molecular weights include, but are not limited to, the range of about 2,000 to about 2,000,000. For example, the following products sold by BASF are suitable: KOLLIDON 12PF (2,000- 3,000 MW); KOLLIDON 17PF (7,000-11,000 MW); KOLLIDON 25 (8,000-34,000 MW); KOLLIDON 30 (4,000-54,000 MW); KOLLIDON 90 (1,000,000-1,500,000 MW).

In one embodiment, the hydrogels employed in this invention are characterized by being tacky viscoelastic solids which, in the rolling ball tack test (ASTM Designation: D 3121-94 (Reapproved 1999)), typically give a rolling ball distance of greater than about 25 mm. It is understood that in one embodiment, the thickness of the hydrogel may range from about 5 mm to about 30 mm, and, more particularly, from about 5 mm to about 10 mm.

The hydrogels are a homogeneous aqueous mixture of water and a cross-linked polyethylene oxide or polyvinylpyrrolidone or a combination thereof. The crosslinking is typically done by electron beam. Not only are they substantially or completely free of unbound water, the advantages of which are discussed above, they are substantially or completely free of discrete polymer particles which could settle out or otherwise adversely affect the physical, electrical or chemical properties of the gels. The polymer contents of the gels are about 4 to about 35 wt % of total.

In one embodiment, suitable hydrocolloids that may be used in the present invention include hydrocolloids that have been sufficiently modified so that the hydrocolloid is either more or less hydrophilic and thus, less or more hydrophobic. In yet another embodiment, suitable hydrocolloids that may be used in the present invention include hydrocolloid that have been chemically modified so that the hydrocolloid' s tackiness has been increased or decreased. For example, in one embodiment, the hydrocolloid employed in the present invention is sufficiently modified so that, when measured by ASTM D 2765-95, the hydrocolloid has a swell ratio of about 1% to about 100% (i.e. a swell ratio of about 0.1 times to about 1 times its original weight), more particularly from about 1% to about 35%, and more particularly from about 5% to about 15%. In contrast, typical hydrocolloids have a swell ratio of about 350% to greater than about 1000% (when measured by ASTM D 2765-95). The table below is swell ratio data for one example of a hydrocolloid that is suitable for the present invention (measured by ASTM D 2765-95).

SWELL RATIO - BASE VS PERCENT SWELL

In one embodiment, the hydrocolloid is an adhesive composition comprising a polyurethane film backing coated with a complex of copolymers consisting of styrene-olefin- styrene tri-block chains extended by hydrocarbon tackifiers and petroleum plasticizers. For example, Euromed has developed a hydrocolloid of this composition. Other manufacturers include Avery Dennison, LecTec Corp., Precision Coatings and Tapemark Medical/Industrial Fabricating Div. In yet another embodiment, the hydrocolloids employed in this invention are characterized by being tacky viscoelastic solids which, in the rolling ball tack test (ASTM Designation: D 3121-94 (Reapproved 1999)), typically give a rolling ball distance of less than about 2mm to about 10 mm , more particularly, from about 3 mm to about 5 mm.

In a further embodiment, the hydrocolloid used in the present invention may be synthetically prepared or naturally occurring. Varieties of hydrocolloids within the scope of the present invention include synthetic polymers prepared from single or multiple monomers, naturally occurring hydrophilic polymers or chemically modified naturally occurring hydrophilic polymers. Non-limiting examples of such hydrocolloids include polyhydroxyalkyl acrylates and methacrylates, polyvinyl lactams, polyvinyl alcohols, polyoxyalkylenes, polyacrylamides, polyacrylic acid, polystyrene sulfonates, natural or synthetically modified polysaccharides, alginates, xanthan gums, guar gums, and cellulosics. When used in medical applications, the hydrocolloid must also be dermatologically acceptable and non-reactive with the skin of the patient or other components of the composition.

Suitable hydrocolloids include synthetic polymers that may be either linear or crosslinked. Non-limiting examples of synthetic hydrocolloids include polymers prepared from N-vinyl lactams, e.g. N-vinyl-2-pyrrolidone, 5-methyl-N-vinyl-2-pyrrolidone, 5-ethyl-N- vinyl-2-pyrrolidone, 3,3-dimethyl-N-vinyl-2-pyrrolidone, 3-methyl-N-vinyl-2-pyrrolidone, 3- ethyl-N-vinyl-2-pyrrolidone, 4-methyl-N-vinyl-2-pyrrolidone, 4-ethyI-N-vinyl-2-pyrrolidone, N-vinyl-2-valerolactam, and N-vinyl-2-caprolactam. Other monomers useful to prepare a synthetic hydrocolloid include hydroxyalkyl acrylates and methacrylates, (such as 2- hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2- hydroxypropyl methacrylate, 2,3-dihydroxypropyl methacrylate), acrylic acid, methacrylic acid and a tertiary amino-methacrylimide, (e.g. trimethylamino-methacrylimide), crotonic acid, and pyridine. Additional monomers useful to prepare a synthetic hydrocolloid include water soluble amides, (such as N-(hydroxymethyl)acrylamide and -methacrylamide, N-(3- hydroxpropyl)acrylamide, N-(2-hydroxy ethyl) methacrylamide, N-(l,l-dimethyl-3- oxabutyl)acrylamide N-[2-(dimethylamine)ethyl]acrylamide and -methacrylamide, N-[3- (dimethylamino)-2-hydroxylpropyl]methacrylamide, and N-[l, l-dimethyl-2-(hydroxymethyl)- 3-oxabutyl]acrylamide); water-soluble hydrazine derivatives, (such as trialkylamine methacrylimide, and dimethyl-(2-hydroxypropyl)arnine methacrylimide); mono-olefinic sulfonic acids and their salts, (such as sodium ethylene sulfonate, sodium styrene sulfonate and 2-acrylamideo-2-methylpropanesulfonic acid); and the following monomers containing nitrogen in the non-cyclic or cyclic backbone of the monomer: 1-vinyl-imidazole, 1-vinyl- indole, 2-vinyl imidazole, 4(5)-vinyl-imidazole, 2-vinyl-l-methyl-imidazole, 5-vinyl- pyrazoline, 3-methyl-5-isopropenyl-pyrazole, 5-methylene-hydantoin, 3-vinyl-2-oxazolidone, 3-methacrylyl-2-oxazolidone, 3-methacryIyl-5-methyl-2-oxazolidone, 3-vinyl-5-methyl-2- oxazolidone, 2- and 4-vinyl-pyridine, 5-vinyl-2-methyl-pyridine, 2-vinyl-pyridine-l -oxide, 3- isopropenyl-pyridine, 2- and 4-vinyl-piperidine, 2- and 4-vinyl-quinoline, 2,4-dimethyI-6- vinyl-s-triazine, and 4-acrylyl-morpholine.

Crosslinking of the linear polymer chains of the hydrocolloid may be desired to modify the tackiness of the hydrocolloid composition. When such crosslinking is desired for polymers made from vinyl monomers discussed above, a multi-ethylenically unsaturated compound with the ethylenic groups being vinyl, allyl, or methallyl groups bonded to nitrogen, oxygen or carbon atoms can be used. Non-limiting examples of crosslinking agents for vinyl containing polymers include divinyl, diallyl, or dimethallyl esters (e.g. ethylene glycol dimethacrylate, divinyl succinate, divinyl adipate, divinyl maleate, divinyl oxalate, divinyl malonate, divinyl glutarate, diallyl itaconate, diallyl maleate, diallyl fumarate, diallyl diglycolate, diallyl oxalate, diallyl adipate, diallyl succinate, diallyl azelate, diallyl malonate, diallyl glutarate, dimethallyl maleate, dimethallyl oxalate, dimethallyl malonate, dimethallyl succinate, dimethallyl glutarate, and dimethallyl adipate); divinyl, diallyl or dimethallyl ethers (e.g. diethylenegtycol divinyl ether, butane diol divinyl ether, ethylene glycol divinyl ether, ethylene glycol diallyl ether, diethylene glycol diallyl ether, butane diol diallyl ether, ethylene glycol dimethallyl ether, diethylene glycol dimethallyl ether, and butane diol dimethallyl ether); divinyl, diallyl or dimethallyl amides including bis(N-vinyl lactams), (e.g., 3,3'- ethylene bis(N-vinyI-2-pyrrolidone) and methylene-bis-acrylamide); and divinyl, diallyl and dimethallyl ureas.

Nonlimiting hydrocolloids for the present invention also include polysaccharides including" starch, glycogen, hemicelluloses, pentosans, gelatin, celluloses, modified celluloses, pectin, chitosan, and chitin. Modified celluloses include methyl cellulose, hydroxypropyl methyl cellulose, carboxymethylcellulose, and hydroxypropyl cellulose. In another embodiment, a water soluble or swellable hydrocolloid may be chosen from the group consisting of polyvinyl alcohols, powdered pectin, gelatin, methyl cellulose, hydroxypropyl methyl cellulose, carboxymethylcellulose, hydroxypropyl cellulose and mixtures thereof. In one preferred embodiment, the hydrocolloid is carboxymethylcellulose (CMC).

In yet another embodiment, the composite structure of the present invention protects the wound from contamination by materials from the outside environment and also prevents the wound from exposing contaminants into the local environment of the patient, i.e. the hospital room. The treatment volume formed over the wound site can be controlled to create an optimal healing environment. The word "wound" as used herein refers generically to surgical incisions, ulcers, or other lesions or breaks in the skin.

The present invention covers a composite structure composed of a sheet or similar geometry of a hydrocolloid with a hydrogel, which is dimensionally smaller than the hydrocolloid sheet, placed on the hydrocolloid. The placement of the hydrogel on the hydrocolloid creates an "island dressing." Fig. 1 is an example of an "island dressing" where hydrocolloid 1 is the rectangular base structure and hydrogel 2 is the circular piece placed on hydrocolloid 1. In this example, the hydrogel encircles the wound area on the surface of the patient's skin. This hydrogel is self supporting and provides an upper surface to support a barrier layer above the level of the wound. The hydrocolloid serves as an adhesive to facilitate attachment of the wound covering to the skin of the patient while, simultaneously, bonding to the hydrogel without the addition of any added adhesives. It is understood that an increase in the tackiness of the hydrocolloid may be related to an increase in the adhesive ability of the hydrocolloid and, by changing the chemistry of the hydrocolloid, the tackiness (e.g. adhesion) will change. Thus, the hydrocolloid may serve both as a barrier layer and an adhesive. Together these two elements form an enclosure or wound treatment volume over the wound site. The fact the barrier layer does not contact the wound itself promotes healing by minimizing mechanical stresses on the tissues. The barrier layer spans the entire wound area. As will be discussed in the various examples and illustrations detailed below, the two basic components of the wound covering are combined with other elements to provide an optimal healing environment at the wound site.

In yet another embodiment, controlling the amount of water in the hydrogel may control the climate within the wound treatment volume. For example, the amount of water in the hydrogel may range from about 20 wt.% to about 98 wt.%, in another embodiment from about 85 wt.% to about 96 wt.%, and further embodiments from about 30 wt.% to about 90 wt.%, from about 40 wt.% to about 70 wt.% and from about 50 wt.% to about 60 wt.%. Also medications or compounds can be control released into the wound by controlling the amount of this material in the hydrogel. For example, the amount of medication or other compounds in the hydrogel may range from about 0.05 to about 5 % based on the weight of the hydrogel, more particularly from about 1% to about 3%. Suitable medications and compounds include water-based or emulsified material including, but not limited to, anti-microbial agents (e.g. silver compounds, essence oils, tints, pigments, Aloe, and vitamins such as Vitamin "E", Vitamin C and/or Vitamin "K." It will be understood by those skilled in the art that numerous other factors can be controlled within the treatment volume of the present wound covering system without departing from the scope of the invention.

FIG. 1 illustrates a cross-section and plan view of one embodiment of the present invention. In this embodiment, the hydrocolloid is substantially square in outline. Hydrocolloid 1 is intended to be attached to uninjured skin surrounding the wound area by using the inherent adhesive properties of the hydrocolloid. In this embodiment, the hydrocolloid isolates the wound from the environment. The hydrocolloid is fabricated from a material which is elastic and conforms to the curved surface of the patient's body. The hydrogel forms a reservoir to contain and release moisture or water vapor into the air within the treatment volume to create a high humidity environment if desired. Additionally, the hydrophilic absorbent nature of the hydrogel may absorb extrudates from the wound.

It will be understood by those skilled in the art that the volume of the hydrogel will depend on the structural strength of the support material (i.e. hydrocolloid) and the amount of fluid absorption desired. Additionally, the total area of the hydrogel is dependent on the size of the wound. For example, larger wounds and more flexible covers will require a larger hydrocolloid so that the hydrogel is large enough to completely cover the wound and there is sufficient hydrocolloid area around the hydrogel to sufficiently adhere to the patient's skin.

The hydrogel is sealed around the wound by extending the hydrocolloid over a sufficient area around the wound to sufficiently adhere to the skin without falling off during use. The adhesive for attaching the hydrogel to the wound area is based on the inherent adhesive properties of the hydrocolloid of the present invention. For this reason, no additional adhesive compound is necessary but, in another embodiment, an additional adhesive compound may be used to either increase the bond of the hydrogel to the hydrocolloid and/or to increase the adhesion of the hydrocolloid to the patient. It will be understood by those skilled in the art that the hydrocolloid and hydrogel composite of the present invention may be supplied in a variety of shapes and sizes to accommodate various wounds. The shapes may include, but are not limited to, circles, squares, triangles or rectangles. Examples of sizes include a rectangle of about 1 by about 3 inches and a rectangle of about 0J by about 3 inches. In yet another embodiment, the composite structure may be provided in large sheets which may be cut to a desired size. In another embodiment, the hydrogel and the hydrocolloid of the present invention are configured separately and then assembled to achieve the desired geometric composite configuration.

The following is one example of a specific method of constructing the composite of the present invention. Figure 2 is merely an illustration of an example of this embodiment and, as such, is not drawn to scale — each element is not necessarily proportionally drawn to other elements of the drawing. It is understood that this example and Fig. 2 are not meant to limit the present invention to this specific construction and/or this specific method. Moreover, the following steps do not necessarily have to be done in the order described. Fig. 2 illustrates a three component composition: (a) hydrocolloid 10; (b) liner 12; and (c) hydrogel 14.

In Fig. 2, liner 12 is composed of a material that acts as a substantial moisture barrier between hydrocolloid 10 and hydrogel 14 so as to substantially inhibit migration of water from hydrogel 14 to hydrocolloid 10. Suitable liners 12 include materials with relatively low moisture vapor transmission rates such as polyethylene, linear low density polyethylene, MDPE/HDPE, esters, or other low moisture vapor transmission rate plastics or compositions. Other suitable material for liner 12 may include composite structures such as a urethane/nonwoven composite. Liner 12 is formed in a geometry such that liner 12 fits between hydrogel 14 and hydrocolloid 10. In Fig. 2, since hydrogel 14 and hydrocolloid 10 are of a sheet geometry, liner 12 is also a sheet geometry. Since an increase in the thickness of liner 12 may be proportional (either directly or indirectly) to the ability to inhibit migration of water through liner 12, the thickness of liner 12 may be chosen based (e.g. in conjunction with the specific material) on the degree of inhibition desired. For example, in one embodiment, the thickness of the liner may range from about 0.5 mils to about 20 mils, more particularly from about 1.5 mils to about 3 mils. In this example, liner 12 is treated so that the liner surfaces contacting elements 10 and 14 are compatible with these elements. In another example, liner 12 may be selected that already has compatible surfaces. In one such treatment, the surface of liner 12, which contacts the surface of hydrocolloid 10, is cleaned with alcohol or other comparable cleaning materials. The surface of liner 12, which contact the surface of hydrogel 14, may be treated with a conventional corona treated process. Subsequently, the surface of liner 12, which has been corona treated, is contacted with hydrogel 14 and is cross- linked with hydrogel 14 by using a conventional electron beam process - forming a cross-link matrix between hydrogel 14 and liner 12. The composite structure of the present invention is then formed by contacting the surface of liner 12, which is not contacting hydrogel 14, with the surface of hydrocolloid 10.

The following are further examples of applications for the present invention. This list is not meant to limit the present invention but merely to illustrate examples of applications. For example, the composite of the present invention may be used in the area of ultrasound testing. In one example, an ultrasonic digital scanner ("LDS") is a low energy, high frequency scanner. In this application, the LDS scans through the hydrogel that serves as a coupling system for the LDS. One advantage of the present invention is that the wound covering, which is composed of the composite of the present invention, may be left on the wound and thus, may be used both as the dressing and the coupling system for the LDS. The result is that the dressing does not have to be removed to observe the progress of the wound healing.

In yet another embodiment, the composite of the present invention is adaptable to allow for placing additives into the hydrogel for wound treatment, skin treatment or any epidermal area (especially for irritations and inflammations).

Another advantage of the composite of the present invention is that the wound management system may be custom-designed for the desirable end-use. For example, the composite structure of the present invention may be any desirable geometric configuration including, but not limited to, circular, rectangular, square, triangular, oval and any desirable size or dimension. A desirable additive (e.g. medical or cosmetic) may be introduced into the hydrogel. A hydrogel and/or hydrocolloid may be chosen have the desirable thickness and/or tackiness.

In another embodiment, the composite of the present invention may be a covering in the area of blood transfusions lines, PEG tubes, catheters and other similar devices that enter the body. For example, the composite may be a hydrogel, which is an island, placed on a hydrocolloid with about 14" colloid border around each of three sides and about a 2" border on the 4th side which would hold down the transfusion line. Suitable additives may include plain anti-microbial agents, Aloe, and/or Vitamin "E".

The composite structure of the present invention may be specifically used for wound management where an antimicrobial agent of a complex silver compound is infused into the hydrogel. In one example, the complex silver compound comprises one or both of the following: a silver compound made by Health Shield Technologies and/or made by Intelligents Biocides. As such, the amount of release and the time period of release of the complex silver compound to the wound may be controlled by adjusting, among other things, the amount of the compound, the composition of the hydrogel and the amount of water in the hydrogel.

In a further embodiment, the composite of the present invention covers blood withdrawal lines (e.g. used by the Red Cross). For example, the composite may be a hydrogel, which is an island, placed on a hydrocolloid with about ^lA" colloid border around each of the 4 sides. The needle punches through the hydrogel that contains an anti-microbial agent. Suitable additives also include plain anti-microbial agents, Aloe, and/or Vitamin "E"..

In yet another embodiment, the composite of the present invention covers ostomy products including side pouches and coverings. For example, the composite may be a hydrogel, which is an island, placed in a hydrocolloid with about V₂" colloid border around each of the 4 sides. The hydrogel may have an anti-microbial added. The size is determined depending on the patients needs. Suitable additives may include plain anti-microbial agents, Aloe, and/or Vitamin "E", or Vitamin "K".

In a further embodiment, the composite of the present invention covers intervenis covering PEG tube covering catheterization. For example, the product may be a hydrogel, which is an island, placed in a hydrocolloid with about VY colloid border around each of three sides and about a 2" border on the fourth side which would hold down the intervention line. Suitable additives may include plain anti-microbial agents, Aloe, and/or Vitamin "E"..

In another embodiment, the composite of the present invention covers a topical for the toes, topical for the heels. For example, the product may be a hydrogel, which is an island, placed in a hydrocolloid with about VY colloid boarder around each of four sides. The hydrocolloid may be shaped for the specific application, such as the toe, the heel or the finger. Suitable additives may include anti-microbial agents and/or aluminum acetate.

In yet another embodiment, the composite of the present invention covers general topical application, sun burn, small bites, rashes/irritation, small isolated burns. For example, the product may be a hydrogel, which is an island, placed in a hydrocolloid with about ^lΛ" colloid border around each of four sides. The hydrocolloid may be shaped for the specific application, such as size of the expected treated area. Suitable additives may include antimicrobial agents, Aloe, and/or Vitamin "E", and aluminum acetate.

In a further embodiment, the composite of the present invention covers eye covering. For example, the composite may be a hydrogel, which is an island, placed in a hydrocolloid with about V₂" colloid border around each of four sides. In one example, the hydrocolloid may be shaped like an egg to fit the eye configuration, and the hydrogel may be floating and circular. Suitable additives include anti-microbial agents, Aloe, and/or Vitamin "E", and aluminum acetate

In another embodiment, the composite of the present invention covers St. Johns Wort remover, Dry Skin (uses with a cream) Acne Care, Blemish Treatment, Aroma Therapy. For example, the composite may be a hydrogel, which is an island, placed in a hydrocolloid with about VY colloid border around each of four sides. The Hydrocolloid may be shaped to the specific application, such as size of the expected treated area. Suitable additives may include Anti-microbial agents, Aloe, Vitamin "A", Vitamin "C", Vitamin "E", Vitamin "K", Essence Oils.

In yet another embodiment, the composite of the present invention covers any cream/ointments, using the window dressing as a cover. For example, the composite may be a hydrogel, which is an island, placed in a hydrocolloid with about ^lA" colloid border around each of four sides. The hydrocolloid may be shaped to the specific application, such as size of the expected treated area.

While the invention has been illustrated by means of specific embodiments, it will be evident to those skilled in the art that many variations and modifications may be made therein.

Claims

What is claimed:

1. A composite structure comprising a hydrogel, a hydrocolloid and a liner between the hydrogel and hydrocolloid, wherein the liner is composed of a material that acts as a substantial moisture barrier between the hydrocolloid and the hydrogel.

2. The composite structure of claim 1 wherein the composite comprises a sheet of the hydrocolloid and the hydrogel, wherein the hydrogel sheet is dimensionally smaller than the hydrocolloid sheet; the hydrocolloid is composed of a material that serves as: a) an adhesive to sufficiently facilitate attachment of the composite structure to skin of a patient; b) a bonding agent to sufficiently bond the liner to the hydrocolloid; and c) a substantial barrier layer to an outside environment.

3. The composite structure of claim 1 wherein the composite is an island dressing.

4. The composite structure of claim 3 wherein the liner is selected from the group consisting of relatively low moisture vapor transmission polyethylene, linear low density polyethylene, and MDPE/HDPE.

5. A composite structure comprising a hydrogel and a hydrophobic hydocolloid.

6. A composite structure comprising a hydrogel and a hydrocolloid, wherein the hydrocolloid has a swell ratio less than about 100% as measured by ASTM- D 2765 - 95 test method.

7. The composite structure of claim 6 wherein the swell ratio is less than about 35%.

8. The composite structure of claim 6 wherein the composite is an island dressing.

9. The composite structure of claim 8 further comprising a liner between the hydrogel and the hydrocolloid, wherein the liner is composed of a material that acts as a substantial moisture barrier between the hydrocolloid and the hydrogel.

10. The composite structure of claim 6 wherein the composite structure is a wound care management system that incorporates the hydrogel having a sufficiently high water content to assist in moist healing and a hydrocolloid having a high solids content.

11. The composite structure of claim 6 wherein the hydrogel comprises one of two types of base polymers or mixtures thereof wherein the first polymer base is polyethylene oxide and the second polymer base is polyvinylpyrrolidone.

12. The composite structure of claim 6 wherein the composite structure is a wound covering for use with an ultrasonic digital scanner.

13. The composite structure of claim 6 wherein the composite structure comprises at least one additive contained in the hydrogel for wound treatment.

14. The composite structure of claim 6 wherein the composite structure comprises at least one additive contained in the hydrogel for skin treatment.

15. The composite structure of claim 6 wherein the composite is a geometric configuration selected from the group consisting of circular, rectangular, square, triangular, and oval dimensions.

16. The composite structure of claim 6 wherein the composite structure comprises a covering for a device that enters the body, the device is selected from the group consisting essentially of blood transfusions lines, PEG tubes, and catheters.

17. The composite structure of claim 6 wherein the composite structure comprises an anti-microbial agent of a complex silver compound infused into the hydrogel.

18. The composite structure of claim 6 wherein the composite structure comprises a covering for ostomy products.

19. The composite structure of claim 6 wherein the composite structure comprises a covering for the eye. ,

20. The composite structure of claim 6 wherein the composite structure comprises a skin covering having at least one cream/ointment.

21. A method of producing a hydrogel/hydrocolloid island dressing comprising the following steps: a) forming a liner of sufficient geometry such that the liner fits between the hydrogel and hydrocolloid, wherein the liner is composed of a material that acts as a substantial moisture barrier between hydrocolloid and hydrogel; b) treating a surface of the liner, which contacts a surface of the hydrocolloid; c) contacting and cross-linking the liner's treated surface with the hydrogel to form a cross-link matrix between the hydrogel and the liner; and d) contacting a surface of the liner, which is not contacting the hydrogel, with the surface of hydrocolloid.

22. The method of claim 20 wherein the cross-linking step uses an electron beam process.