# US 8,772,567 B2 · Use of a polyurethane foam as a wound dressing in negative pressure therapy

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- Number: US 8,772,567 B2
- Document ID: US8772567B2
- Status: Granted
- Kind: B2
- Application number: 13/213,214
- Filed: 2011-08-19
- Published: 2012-02-23
- Granted: 2014-07-08
- Earliest claimed: 2010-08-19
- Assignees: Paul Hartmann AG
- Applicants: Axel Eckstein; Pierre Croizat; Ulrich Fink; Krzysztof-Daniel Malowaniec
- Inventors: Axel Eckstein; Pierre Croizat; Ulrich Fink; Krzysztof-Daniel Malowaniec
- Web page: https://patentgrep.com/patent/US8772567B2

## CPC

- A61F 13/05: specially adapted for use with sub-pressure or over-pressure therapy, wound drainage or wound irrigation, e.g. for use with negative-pressure wound therapy [NPWT]
- A61F 13/01017: {synthetic, e.g. polymer based}
- A61L 15/26: Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof {(A61L15/225 takes precedence)}
- A61L 15/425: {Porous materials, e.g. foams or sponges}
- A61L 15/46: Deodorants or malodour counteractants, e.g. to inhibit the formation of ammonia or bacteria
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K)

## Abstract

A device for negative pressure wound therapy having a cover material for air-tight sealing of the wound space connected to a negative pressure source; and a wound dressing having an open-cell polyurethane foam. The open-cell polyurethane foam has special properties, in particular a tensile strength after three days of storage in bovine serum, measured in accordance with DIN 53571, between 80 kPa and 300 kPa. The open-cell polyurethane foam may be used as a wound dressing in negative pressure wound therapy.

## Claims

### Claim 1

A device for negative pressure wound therapy comprising
(a) a cover material for air-tight sealing of a wound space;
(b) optionally, a connector of a negative pressure source; and
(c) an open-cell polyurethane foam as a wound dressing, obtained by reaction of a mixture comprising the components
(i) polyisocyanate,
(ii) polyol,
(iii) blowing agent, and
(iv) catalyst,
whereby the open-cell foam, after three days of storage in bovine serum, has a tensile strength, measured in accordance with DIN 53571, between 80 kPa and 300 kPa, and
whereby the open-cell polyurethane foam has an air permeability of 1,000 to 8,000 l/(m2sec), measured in accordance with DIN EN ISO 9237.

### Claim 2 (depends on 1)

The device in accordance with claim 1, whereby the open-cell polyurethane foam has a tensile strength after three days of storage in bovine serum, measured in accordance with DIN 53571, between 150 kPa and 220 kPa.

### Claim 3 (depends on 1)

The device in accordance with claim 1, whereby the (i) polyisocyanate is selected from the group consisting of MDI, PMDI and TDI.

### Claim 4 (depends on 1)

The device in accordance with claim 1, whereby the (ii) polyol is a polyester polyol obtainable by reaction of a dicarboxylic acid with 4 to 8 carbon atoms with a dialcohol with 2 to 6 carbon atoms.

### Claim 5 (depends on 1)

The device in accordance with claim 1, whereby the (ii) polyol is a polyester polyol having a weight average molecular weight of 500 to 4,000 g/mol.

### Claim 6

A device for negative pressure wound therapy comprising
(a) a cover material for air-tight sealing of a wound space;
(b) optionally, a connector of a negative pressure source; and
(c) an open-cell polyurethane foam as a wound dressing, obtained by reaction of a mixture comprising the components
(i) polyisocyanate,
(ii) polyester polyol,
(iii) blowing agent, and
(iv) catalyst,
whereby the open-cell foam, after three days of storage in bovine serum, has a tensile strength, measured in accordance with DIN 53571, between 80 kPa and 300 kPa,
whereby the open-cell polyurethane foam has a ductile yield of 250% to 650%, measured in accordance with DIN 53571.

### Claim 7 (depends on 1)

The device in accordance with claim 1, whereby the open-cell polyurethane foam has a raw density between 15 and 30 kg/m3, measured in accordance with DIN EN ISO 845.

### Claim 8 (depends on 1)

The device in accordance with claim 1, whereby the open-cell polyurethane foam has a proportion of aromatic compounds of 5 to 50%.

### Claim 9 (depends on 1)

The device in accordance with claim 1, whereby the open-cell polyurethane foam has a hardness of 20 to 70 Shore A, measured in accordance with DIN 53505.

### Claim 10 (depends on 1)

The device in accordance with claim 1, whereby the open-cell polyurethane foam has a cell number of 5 to 25 cm−1.

### Claim 11 (depends on 1)

The device in accordance with claim 1, whereby the open-cell polyurethane foam displays visco-elastic behavior.

### Claim 12 (depends on 1)

The device in accordance with claim 1, whereby the cover material (a) has a water vapor permeability of 100 to 2,500 g/m 2×24 h, measured in accordance with DIN EN 13726-2.

### Claim 13

A method for negative pressure wound therapy, said method comprising
dressing a wound with an open-cell polyurethane foam obtained by reaction of a mixture comprising the components
(i) polyisocyanate,
(ii) polyol,
(iii) blowing agent, and
(iv) catalyst,
wherein the open-cell foam is selected such that after three days of storage in bovine serum it has a tensile strength, measured in accordance with DIN 53571, between 80 kPa and 300 kPa, and wherein the open-cell polyurethane foam has an air permeability of 1,000 to 8,000 l/(m2sec), measured in accordance with DIN EN ISO 9237, and
applying negative pressure to the wound.

### Claim 14 (depends on 13)

The method of claim 13, wherein the wound is a burn wound, a wound caused by mechanical trauma, a wound caused by exposure to chemicals, a wound caused by a metabolic disorder, a wound caused by a circulatory disorder, a wound caused by radiation induced ulcer, a wound caused by diabetic foot ulcer, or a wound caused by pressure ulcer.

### Claim 15 (depends on 13)

The method of claim 13, wherein the (ii) polyol is a polyester polyol.

### Claim 16 (depends on 13)

The method of claim 13, wherein the (i) polyisocyanate is selected from the group consisting of MDI, PMDI and TDI.

### Claim 17 (depends on 15)

The method of claim 15, wherein the (ii) polyester polyol is obtained by reaction of a dicarboxylic acid with 4 to 8 carbon atoms with a dialcohol with 2 to 6 carbon atoms.

### Claim 18 (depends on 1)

The device of claim 1, wherein the (ii) polyol is a polyester polyol.

### Claim 19 (depends on 18)

The device of claim 18, whereby the open-cell foam, after three days of storage in bovine serum has a tensile strength, measured in accordance with DIN 53571, between 150 kPa and 220 kPa.

### Claim 20 (depends on 18)

The device of claim 18, wherein the (i) polyisocyanate is selected from the group consisting of MDI, PMDI and TDI.