WO2006007846A2

WO2006007846A2 - A dressing comprising a serine protease inhibitor and an antioxidant

Info

Publication number: WO2006007846A2
Application number: PCT/DK2005/000496
Authority: WO
Inventors: Flemming Reissig Jensen
Original assignee: Coloplast AS
Current assignee: Coloplast AS
Priority date: 2004-07-16
Filing date: 2005-07-14
Publication date: 2006-01-26
Anticipated expiration: 2007-01-16
Also published as: WO2006007846A3

Abstract

The invention provides the use of a Serine Protease Inhibitor (SPI) in combination with an antioxidant, to achieve an improved and synergistic effect on the healing of wounds, especially chronic wounds, such as pressure sores or leg ulcers. The invention also includes the use of antioxidants as stabilizing entities during the production, transport, storage and sterilisation of compositions, such as pharmaceutical compositions or medical devices, containing oxidatively sensitive active pharmaceutical entities, such as SPI's.

Description

TITLE

A Dressing

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to dressings, particularly dressings for promoting the healing of a wound, comprising enzyme inhibitors. Furthermore, the invention relates to a composition and use of such composition for promoting the healing of a wound.

The world has seen a dramatic increase in number of elderly people an increase that is estimated to continue in the future. It is estimated that the world's elderly population (> 65) will grow from approximately 500 mio. in 1997 to more than one billion in 2030. The increase is driven by an increased life expectancy in general combined with a low birth in the developed world.

Chronic wounds typically affect people over 65, due to the underlying clinical complications typically associated with chronic wounds, such venous and arterial insufficiency, diabetes and trauma caused by bed-rest. Type 2 diabetes is expected to grow significantly in the next 20 years; in the US type 2 diabetes is estimated to increase by 14 % per year, doubling every 5 years, an increase inevitably resulting in a corresponding increase in the number of diabetic foot ulcers.

In the USA, an estimated 4 mio. patients are treated for a chronic wound annually, a number expected to rise to more 6 mio in 2005. The associated cost of treatment is in excess of 10 billion US$. The number of wounds seen in the EU is more than 3 mio per year, expected to increase to more than 5 mio wounds in 2005.

Besides the economic aspects of chronic wound treatment, the patients is suffering tremendously from a combination of infections, pain and low quality of life, combined with a significant increased risk of amputation of limbs and premature death.

Current treatment of chronic wounds varies across the world, but is fundamentally based on passive bandages facilitating moist wound healing and exudate control.

It is therefore essential that efficient treatment of chronic wounds be developed, treatments based on the active manipulations of factors in wound.

2. Description of the Related Art

Serine Proteases are hydrolytic enzymes naturally occurring in Man. This family of enzymes has many functions in the human physiology, e.g. in the immune system, developmental, cancer and inflammatory pathways. Human Neutrophil Elastase (HNE, synonyms: elastase, leukocyte elastase, lysosomal elastase) is a Serine Protease, and is one of several hydrolytic enzymes contained in the azurophil granules of human neutrophils. Elastase is involved in the inflammatory response upon wounding, and as such, Elastase is involved in the degradation of foreign material ingested during phagocytosis, as well the degradation of extracellular matrix components such as collagen, Fibronectin and Elastin. It has been demonstrated that levels of elastase activity are elevated in chronic wound fluids and that elastase contributes to the overall increase in proteolytic activity of the chronic wound environment.

Elastase, present in chronic wound fluid, is the enzyme responsible for the degradation of several extracellular constitutive matrix proteins such as fibronectin, collagen and Elastin as well as the degradation of peptide growth factors such as PDGF and TGF-β. Moreover, cell surface receptors for peptide growth factors may themselves be functionally inactivated by the actions of elastase. Under normal physiological conditions, the activity of serine proteases such as elastase is tightly controlled by naturally occurring inhibitors, such as SLPI, AAT or Elafin.

One important serine protease is SLPI, which is a 11.7 kDa unglycosylated protein [Bingle L, Thorax 1996, 51 :1273-1274], known to be a potent inhibitor of several serine proteases such as human neutrophil elastase, mast cell chymase and Cathepsin G. SLPI Is a hydrophobic cationic protein and will bind readily to elastase and some of its substrates such as elastin and other extraxcellular matrix components. SLPI can furthermore inhibit elastin-bound elastase. The interaction between SLPI and elastase is reversible.

Elastase is pro-inflammatory and SLPI therefore has an important anti¬ inflammatory role. Interestingly, in vitro experiments have demonstrated that elastase upregulates epithelial cell SLPI mRNA, suggesting feedback control. Similar mechanisms may occur in vivo. Other inflammatory mediators, including IL-1 β and TNF, have a similar stimulatory effect on SLPI mRNA production in lung epithelial cell line

However, SLPI loose anti-elastase activity when exposed to reactive oxygen species (ROS), due to oxidation of the active site methionine to the corresponding sulphoxide. Reactive oxygen species are known to exist in high concentrations in chronic wound exudates. SLPI has recently been implicated in the healing of chronic wounds, as well as a number of other documented in vitro biological and physiological properties, such as anti-microbial (anti-bacterial, anti¬ fungal), anti-inflammatory and anti viral.

Typically, Elastase is controlled-by the α-1 -proteinase inhibitor (α-1 -antitrypsin), a serum protease inhibitor that can penetrate into various tissues. However, studies have shown that the level of α1 -antitrypsin is low in chronic wounds compared to acute wounds. Protease inhibitors normally prevent damage to connective tissue caused by leakage of MMP's, however elastase is known to proteolytically inactivate the specific MMP-inhibitor, TIMP's. In addition, elastase itself may participate in proteolytic activation of collagenase and gelatinase zymogens.

It has been shown that insufficient levels of these inhibitors lead to pulmonary and hereditary emphysema, and elastase in particular has been implicated in abnormal lung connective tissue turnover, as well as being implicated in the non¬ healing of persistent chronic wounds.

AAT is a 52 kDa extensively glycosylated protein, known to be a very potent inhibitor of human neutrophil elastase. Originally isolated from human plasma, AAT can now be produced recombinantly in a less glycosylated version. AAT is the major serum inhibitor of human neutrophil elastase, and the main source of inhibition of elastase in fluids/solution. As seen in the case of SLPI, AAT is the subject of oxidative inactivation through the oxidation of the active site methionine, to the corresponding sulfoxide.

The generation and release from neutrophils of reactive oxygen species (ROS) is a natural part of the inflammatory in response to wounding. It has been demonstrated that ROS are present in high concentrations in chronic wounds, and it is indicated by several groups that high concentrations of ROS lead to impaired healing of cutanous wounds, due to the oxidative damage to e.g. cell walls (lipid peroxidation) resulting in cell death, oxidative destruction of growth factors, impaired collagen synthesis and reduced tissue breaking strength. Furthermore, it has been established that ROS are a cause of inactivation of AAT and SLPI, leading to further tissue damage from un-inhibited or uncontrolled elastase activity.

Antioxidants, e.g. vitamin E, vitamin C and Raxofelast, a synthetic vitamin E analogue, are implicated as being beneficial to the wound healing process, specifically the anabolic phase following initial inflammation. The beneficial effects arise from the potential to neutralize damaging ROS; thereby preventing the above outlined detrimental effects. International patent application No. WO 01/64132 discloses a wound dressing with protease lowering activity provided by protease inhibitors. The dressing may further comprise therapeutically beneficial substances such as antibiotics or vitamins. The reference is silent with respect to use of antioxidants.

The present invention facilitates accelerated healing of chronic wounds as well as improving tissue, minimising the risk of reoccurrence.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a dressing comprising a Serine Protease Inhibitor (SPI), which is not susceptible to degradation.

Another object of the invention is to provide a dressing comprising a SPI, which can be sterilized without significant loss of activity.

A third object of the present invention is to provide composition for enhancing the healing of a wound.

A fourth object of the preset invention is to use a novel composition for the healing of wounds.

A fifth object of the present invention is to provide a composition and a dressing comprising a Serine Protease Inhibitor (SPI), being stable during the production, transport, storage and sterilisation.

Detailed Description of the Present Invention

The invention relates to a dressing for promoting the healing of a wound, said dressing comprising a Serine Protease Inhibitor (SPI), wherein the dressing further comprises one or more antioxidants. The invention provides the use of a Serine Protease Inhibitor (SPI) in combination with an antioxidant, to achieve an improved and synergistic effect on the healing of wounds, especially chronic wounds, such as pressure sores or leg ulcers. The invention also includes the use of antioxidants as stabilizing entities during the production, transport, storage and sterilisation of compositions, such as pharmaceutical compositions or medical devices, containing oxidatively sensitive active pharmaceutical entities, such as SPPs.

The antioxidant may be functioning to protect the SPI from oxidative damage during production, sterilisation, transport and storage as well as oxidative damage from reactive oxygen species (ROS) in the wound environment.

It has surprisingly been shown that by combining the SPI with an antioxidant, the necessary amount of SPI needed for achieving therapeutic effect, may be reduced. As the SPI's often are expensive compounds, this feature may have economic aspects.

The antioxidant may comprise Vitamin E or derivatives or analogues thereof.

It may be preferred that the antioxidant is water-soluble. This may especially be desired when having an aqueous environment during production of the dressing, as well as it may enhance the solubility into the wound site and wound exudates.

The SPI and the antioxidant may be incorporated in the dressing, e.g. by mixing into one or more of the components of the dressing. Thus, the compound may be incorporated in an adhesive or it may be incorporated in an absorbent element, such as a foam or other suitable absorbent material.

In a preferred embodiment of the invention the SPI and the antioxidant are released from the dressing. This renders it possible for the compound to enter deeper into the wound site and carry out its function there. The dressing of the present invention may further comprise one or more active ingredients besides SPI.

The dressing according to the invention may comprise one or more active ingredients, e.g. a pharmaceutical medicament. Examples of such pharmaceutical medicaments such as bacteriostatic or bactericidal compounds, e.g. iodine, iodopovidone complexes, chloramine, chlorohexidine, silver salts such as sulphadiazine, silver nitrate, silver acetate, silver lactate, silver sulphate, silver sodium thiosulphate or silver chloride, zinc or salts thereof, metronidazol, sulpha drugs, and penicillin's, pain-killing agents, tissue-healing enhancing agents, e.g. RGD tripeptides and the like, proteins, amino acids such as taurine, vitamins such ascorbic acid, enzymes for cleansing of wounds, e.g. pepsin, trypsin and the like, proteinase inhibitors or metalloproteinase inhibitors such as Illostat or ethylene diamine tetraacetic acid, cytotoxic agents and proliferation inhibitors for use in for example surgical insertion of the product in cancer tissue and/or other therapeutic agents which optionally may be used for topical application, emollients, retinoids or agents having a cooling effect which is also considered an aspect of the invention.

The active ingredient may also comprise odour controlling or odour reducing material such as charcoal.

In one embodiment of the invention the dressing further comprises a growth factor.

The invention also relates to a method for promoting the healing of a wound by co-administrating an effective amount of SPI and antioxidant to a wound.

Furthermore, the invention relates to a composition for promoting the healing of a wound, said composition comprising a Serine Protease Inhibitor (SPI) and one or more antioxidants. In one aspect of this invention, the composition comprising a serine protease inhibitor in combination with an antioxidant is used for the treatment of inflammation in cutanous ulcers, such as, but not limited to, burns, venous leg ulcers, pressure ulcer and diabetic foot ulcers.

In another aspect of this invention the composition comprising a serine protease inhibitor in combination with an antioxidant is used to prevent and treat tissue destruction due to inflammation.

In yet another aspect of this invention the composition comprising a serine protease inhibitor in combination with an antioxidant is used to improve the quality of tissue in a healed wound and to minimise the risk of reoccurrence.

The composition of the present invention may comprise one or more serine protease inhibitors such as, but not limited to, alfa-1 -antitrypsin (AAT), secretory leukocyte protease inhibitor (SLPI) or Elafin in combination with one or more antioxidants such as, but not limited to, Raxofelast, vitamin E, vitamin C or derivatives or analogues thereof.

The composition may be used for promoting healing of chronic wounds such as, but not limited to, pressure ulcers, arterial leg ulcers, venous leg ulcers and diabetic foot ulcers.

In one embodiment of the invention the composition comprising a serine protease inhibitor in combination with an antioxidant may be delivered to the tissue injury as a topical treatment, e.g. via a pharmaceutically acceptable delivery vehicle.

Still further, the invention relates to the use of a composition for promoting the healing of a wound, said composition comprising a Serine Protease Inhibitor (SPI) and one or more antioxidants. Particularly, the invention relates to the use of a composition for achieving improved or accelerated healing of chronic wounds such as pressure sores, leg ulcers and diabetic foot ulcers, through the synergistically acting co¬ administration of a composition consisting of a Serine Protease Inhibitor (SPI), such as Secretory Leukocyte Protease Inhibitor (SLPI) or alfa-1 -antitrypsin (AAT) and an antioxidant, such as vitamin E or derivatives or analogues thereof.

The invention provides for the use of a composition comprising a serine protease inhibitor in combination with an antioxidant for the treatment of tissue injury. The composition can either be manifested as a pharmaceutical composition or a medical device and can be administered IV, PO, subQ, topically or IP.

Claims

1. A dressing for promoting the healing of a wound, said dressing comprising a Serine Protease Inhibitor (SPI), wherein the dressing further comprises one or more antioxidants.

2. A dressing according to claim 1 wherein the antioxidant comprises Vitamin E or derivatives or analogues thereof.

3. A dressing according to any of the preceding claims wherein the antioxidant is substantially water-soluble.

4. A dressing according to any of the preceding claims wherein the SPI is SLPI or AAT.

5. A dressing according to any of the preceding claims, wherein the SPI and the antioxidant are incorporated in the dressing.

6. A dressing according to any of the preceding claims, wherein the SPI and the antioxidant are released from the dressing.

7. A dressing according to any of the preceding claims, wherein the dressing further comprises a growth factor.

8. A method for promoting the healing of a wound by co-administrating an effective amount of SPI and antioxidant to a wound.

9. A composition for promoting the healing of a wound, said composition comprising a Serine Protease Inhibitor (SPI) and one or more antioxidants.

10. Use of a composition for promoting the healing of a wound, said composition comprising a Serine Protease Inhibitor (SPI) and one or more antioxidants.