WO1996013284A1

WO1996013284A1 - Wound treatment composition

Info

Publication number: WO1996013284A1
Application number: PCT/GB1995/002542
Authority: WO
Inventors: Yimin Qin; Keith Dennis Gilding
Original assignee: Innovative Technologies Limited
Priority date: 1994-10-28
Filing date: 1995-10-30
Publication date: 1996-05-09
Also published as: AU3750395A; GB9421969D0

Abstract

A composition for use in treating a wound, e.g. cavity wounds, comprises a hydrogel containing O-carboxymethyl chitosan or N,O-carboxymethyl chitosan and a plasticising compound.

Description

WOUND TREATMENT COMPOSITION

The present invention relates to compositions which are useful in the treatment

of wounds. The invention relates more particularly to such compositions which

incorporate O-carboxymethyl chitosan (OCC) or N-, O- carboxymethyl chitosan

(NOCC) which are a water soluble derivatives of chitin.

NOCC is a known material and its preparation is disclosed for example in US-

A-4,619,995. Briefly NOCC may be prepared by a solid phase reaction between

chitosan and monochloroacetic acid under alkaline conditions. The degree of

substitution can be varied but is typically 0.6 to 1.0. OCC may be produced by a similar

procedure effected to give a degree of substitution of 0.3-0.5.

According to a first aspect of the present invention there is provided a

composition for use in treating a wound comprising a hydrogel containing OCC or

NOCC and a plasticising compound.

Compositions in accordance with the invention are useful in the treatment of

cavity wounds, e.g. decubitus ulcers. The compositions are introduced into the wound

and pressed firmly into the base thereof. For preference the wound is then covered and

sealed by a film having a high MVTR, typically 3,000 to 12.000 g m^"2 24hr^"' (e.g.

hydroderm (ex Wilshire Medical) or IT425 or IT625 (ex Innovative Technologies)).

The compositions may also be used in the treatment of sinuses.

Preferred compositions in accordance with the invention have a viscosity in the

range 20,000 to 100,000 cP. Compositions in accordance with the invention will generally contain a

maximum of 5% by weight of OCC and/or NOCC. Typically the OCC or NOCC

content will be in the range 2-4%.

The plasticiser will generally be present in a maximum amount of 20% by

weight, more usually in the range 2-20% by weight.

Examples of plasticiser include polyhydroxy compounds, e.g. glycerol, sorbitol,

propylene glycol, and polyethylene glycol (a preferred example of which is PEG 400).

The most preferred plasticiser glycerol.

The aqueous phase of the gel will for preference comprise isotonic buffered saline, e.g. phosphate buffered saline.

Additional components may be included in the composition to enhance their

healing properties. Examples include antimicrobial agents which may be used at a level

of 1-2% of the composition. A preferred anti-microbial agent is chlorhexidine

gluconate.

Antimicrobial properties may also be achieved by use of enzymes, e.g. glucose

oxidase/lactic acid peroxidase enzymes as a natural disinfection system activated by

glucose (present in exudate).

A further possibility is to include a component, e.g. pectin, which facilitates

wound debridement. This component may for example be used in an amount up to

20%, more preferably up to 10%, e.g. 0.05-1% by weight.

Compositions for use in accordance with the invention may be produced in

various ways. For example a composition may be produced by dissolving the required amounts of OCC or NOCC (e.g. 3-5%), plasticiser and any other components in

phosphate buffered saline at 90°C then cooling. The composition may be sterilised by

autoclaving at 120°C for 15 minutes.

The gels obtained may be incorporated into a convenient delivery system, e.g. a

syringe, sachet, tube or squeeze bottle, for introduction into a wound.

The invention is illustrated by the following non-limiting Example.

Example

A gel was produced by dissolving 3-4% NOCC and 1 -2% high methoxy pectin

(Bulmers) in isotonic phosphate buffered saline at pH 7 with 2% glycerol. The gel was

filled into a vessel and autoclaved at 120°C for 15 minutes. The viscosity of the gel

reduced slightly during autoclaving but by no more than 10%.

Claims

1. A composition for use in treating a wound comprising a hydrogel containing OCC or NOCC and a plasticising compound.

2. A composition as claimed in claim 1 containing a maximum of 5% by weight of

OCC and/or NOCC.

3. A composition as claimed in claim 2 containing 2-4% by weight OCC and/or

NOCC.

4. A composition as claimed in any one of claims 1 to 3 wherein the plasticiser is

present in an amount of less than 20% by weight.

5. A composition as claimed in any one of the preceding claims wherein the

plasticiser is a polyhydroxy compound.

6. A composition as claimed in claim 5 wherein the plasticiser is glycerol. sorbitol,

propylene glycol or polyethylene glycol.

7. A composition as claimed in any one of the preceding claims wherein the

aqueous phase of the gel comprises isotonic buffered saline.

8. A composition as claimed in any one of the preceding claims additionally

incorporating an anti-microbial agent.

9. A composition as claimed in claim 8 wherein the anti-microbial agent is

chlorhexidine gluconate.

10. A composition as claimed in any one of claims 1 to 8 incorporating glucose

oxidase/lactic acid hydrogenase enzymes.

11. A composition as claimed in any one of the preceding claims containing pectin

for wound debridement.

12. A composition as claimed in any one of the preceding claims having a viscosity

in the range 20,000 to 100.000 cP.

13. A composition as claimed in any one of the preceding claims which has been

sterilised by autoclaving.

14. A composition as claimed in any one of the preceding claims incorporated in a

delivery system.

15. The combination of a composition as claimed in any one of the preceding claims

and a film having a high MVTR capability.

16. The combination as claimed in claim 15 wherein the film has an MVTR of 3,000

to 12,000 g m^"2 24hr^"'.