Debriding wound dressing, process of manufacture and useful articles thereof

Abstract

A wound dressing for active continuous debridement of devitalized tissues in non-healing wounds including diabetic ulcers, pressure ulcers, burn injuries and other etiologies, includes an active ingredient, such as collagenase, which serves to debride wounds in-situ. In one example, purified Collagenase (90% pure) was deposited onto several wound dressing materials. A key feature of this invention is that the activity level of the Collagenase used was substantially preserved.

Claims

1. A wound dressing for active continuous debridement of devitalized tissues in non-healing wounds, comprising a substrate, the substrate having a non-adherent wound contacting layer having a wound contacting side, the non-adherent wound contacting layer comprising only silicone, the wound dressing having a wound contacting surface, the wound contacting side of the non-adherent wound contacting layer comprising the entire wound contacting surface of the wound dressing, and a coating of an effective amount of an enzymatic debriding agent on and being in direct contact with the wound contacting side of the non-adherent wound contacting layer, the enzymatic debriding agent being collagenase, and the collagenase being 90% pure collagenase, and the collagenase on the wound contacting side of the non-adherent wound contacting layer having a coating weight of 1.31 mg/square centimeter.

2. The wound dressing of claim 1, the substrate comprising a polyester non-woven mesh coated with silicone on one side, and the silicone comprising the non-adherent wound contacting layer.

3. The wound dressing of claim 1, the substrate comprising a polyester non-woven mesh coated on both sides with silicone, and the silicone on either side of the polyester non-woven mesh comprising the non-adherent wound contacting layer.

4. A wound dressing for active continuous debridement of devitalized tissues in non-healing wounds, comprising a substrate, the substrate having a non-adherent wound contacting layer having a wound contacting side, the non-adherent wound contacting layer comprising only silicone, the wound dressing having a wound contacting surface, the wound contacting side of the non-adherent wound contacting layer comprising the entire wound contacting surface of the wound dressing, and a dusting of an effective amount of an enzymatic debriding agent on and being in direct contact with the wound contacting side of the non-adherent wound contacting layer, the enzymatic debriding agent being collagenase, and the collagenase being 90% pure collagenase, and the collagenase on the wound contacting side of the non-adherent wound contacting layer having a coating weight of 1.31 mg/square centimeter.

5. The wound dressing of claim 4, the substrate comprising a polyester non-woven mesh coated with silicone on one side, and the silicone comprising the non-adherent wound contacting layer.

6. The wound dressing of claim 4, the substrate comprising a polyester non-woven mesh coated on both sides with silicone, and the silicone on either side of the polyester non-woven mesh comprising the non-adherent wound contacting layer.

7. A wound dressing for active continuous debridement of devitalized tissues in non-healing wounds, comprising a substrate, the substrate having a wound contacting surface, and the wound contacting surface of the substrate comprising only silicone, and a dusting on the wound contacting surface of the substrate of an effective amount of an enzymatic debriding agent, and the enzymatic debriding agent being collagenase, wherein the collagenase is 90% pure collagenase, and wherein the collagenase on the substrate has a coating weight of 1.31 mg/square centimeter.

8. The wound dressing of claim 7, the substrate comprising a polyester non-woven mesh coated with silicone on one side.

9. The wound dressing of claim 7, the substrate comprising a polyester non-woven mesh coated on both sides with silicone.

10. A wound dressing for active continuous debridement of devitalized tissues in non-healing wounds, comprising a substrate, the substrate having a wound contacting surface, and the wound contacting surface of the substrate comprising only silicone, and a coating on the wound contacting surface of the substrate of an effective amount of an enzymatic debriding agent, and the enzymatic debriding agent being collagenase, wherein the collagenase is 90% pure collagenase, and wherein the collagenase on the substrate has a coating weight of 1.31 mg/square centimeter.

11. The wound dressing of claim 10, the substrate comprising a polyester non-woven mesh coated with silicone on one side.

12. The wound dressing of claim 10, the substrate comprising a polyester non-woven mesh coated on both sides with silicone.

13. A wound dressing for active continuous debridement of devitalized tissues in non-healing wounds, comprising a non-adherent wound contacting layer having a wound contacting side, the non-adherent wound contacting layer comprising only silicone, and the wound contacting side of the non-adherent wound contacting layer having an effective amount of an enzymatic debriding agent on and in direct contact with the wound contacting side of the non-adherent wound contacting layer, the enzymatic debriding agent being collagenase, the collagenase being 90% pure collagenase, and the collagenase on the wound contacting side of the non-adherent wound contacting layer having a coating weight of 1.31 mg/square centimeter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a cross-sectional view of a Rylon wound dressing.

(2) FIG. 2 shows a cross-sectional view of a Dual-Dress wound dressing.

(3) FIG. 3 shows a cross-sectional view of a preferred embodiment of the inventive wound dressing device, constructed in accordance with the invention, in which an enzymatic debriding agent (50) has been deposited into and/or onto the wound contacting surface (25) of the silicone layer (10) of the Rylon wound dressing.

(4) FIG. 4 shows a cross-sectional view of another preferred embodiment of the inventive wound dressing device, constructed in accordance with the invention, in which an enzymatic debriding agent (50) has been deposited into and/or onto the wound contacting surface (45) of the foam layer (30) of the Dual-Dress wound dressing.

(5) FIG. 5 is a schematic view in cross-section of a wound dressing (60) constructed in accordance with the invention, in which an enzymatic debriding agent (50) has been deposited into and/or onto the wound contacting surface (65) of the wound dressing material (70) of the wound dressing (60). Preferably, the wound dressing material is any material used to contact a wound in conventional wound dressings.

(6) FIG. 6 is a schematic view in cross-section of a wound VAC dressing (80) constructed in accordance with the invention, in which an enzymatic debriding agent (50) has been deposited into and/or onto the wound contacting surface (85) of the sponge (90). An occlusive membrane (95) is provided for covering the sponge (90) when the wound VAC dressing is secured over a wound.

(7) FIG. 7 shows a cross-sectional view of a preferred embodiment of the inventive wound dressing, constructed in accordance with the invention, in which an enzymatic debriding agent (50) has been deposited into and/or onto the wound contacting surface (25) of the silicone layer (10) of a Rylon wound dressing that consists of a polyester non-woven mesh coated with silicone on both sides.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(8) In the present invention purified Collagenase (90% pure) from Vitacyte LLC. (Indianapolis, Indiana, USA) was deposited onto several wound dressing materials. The dressing can be sized to fit the wound base so that the viable tissue is not in direct contact with active surface of the dressing. In the case of a foam dressing, the active enzyme may be applied onto the wound VAC foam of all types and materials. The active enzyme will debride the eschar at the same time as macro and microdeformational forces are actively molding the wound for effective healing. This expands the usage of wound VAC dressings where the wound base contains necrotic and eschar tissue.

(9) The following examples are not intended to be limiting, as minor variations on these designs and processes would be obvious to those skilled in the art. Likewise, it is believed that some materials could be substituted and still achieve a substantially similar result. Additionally, there are numerous enzymes and other active ingredients that may be useful.

Example 1

(10) Commercially available Collagenase ointment (Santyl 250 Units/g) was mixed with the silicone matrix as per standard technique. This was submitted to the supplier of the collagenase for evaluation of its release from the matrix. The activity analysis was aimed to determine that the Collagenase enzymes were present in their native state in the extract. There was difficulty in solubilization of the Collagenase for analysis. After 24 hours of extraction of Collagenase from the matrix the supernatant was analyzed and at least one form of Collagenase was found.

Example 2

(11) We used lyophilized 90% pure Vitacyte Collagenase which was shown to be at least 10-20 times more active than Collagenase present in the Santyl. The technique was modified in the form of dusting the Collagenase on the surface of the matrix to create 3 levels of coating: light, medium and heavy. The coating weight was to determine by differential weight analysis and reported by mg/cm.sup.2.

(12) TABLE-US-00001 Qualitative Coating Weight Measured Coating Weight (mg/cm.sup.2 Low 0.18 Medium 0.69 High 1.31

(13) This was likewise submitted for Collagenase activity assays.

(14) For the Collagenase extraction analysis 2 cm.sup.2 piece from the matrix was cut and the backing was peeled off and the matrix was further cut into smaller pieces. The extraction was performed at room temperature. The extracts were then analyzed for Collagenase activity by UV spectroscopy and High Pressure Liquid Chromatography (HPLC). The low and the medium loaded extracts showed little or no intact Collagenase. The high loaded extract (1.3 mg/cm.sup.2) did contain Collagenase enzymes on HPLC analysis although the recovery was very low.

(15) Further experiments were performed with a larger sample of the matrix, as illustrated in Example 3 below.

Example 3

(16) Collagenase extraction was performed as above on 4 cm.sup.2 of each matrix of Example 2. The extraction duration was about 20 hours. The UV absorbance reading for the low and the medium coated matrices did not show any activity, which was consistent with the earlier experiment illustrated in Example 2. In this experiment, the low and medium loaded extracts showed little or no intact Collagenase (0.0248 mg/cm.sup.2 for the low load matrix and 0.0431 mg cm.sup.2 for the medium load matrix). With the high loaded product, there was much more enzyme protein present. The Collagenase activity was 0.427 mg/cm.sup.2. HPLC analysis indicated that the bulk of the material solubilized was Collagenase which was intact and was found to have activity. The high loaded sample had the best percentage recovery of Collagenase activity in comparison to low and medium loaded matrices.

(17) In summary, the inventive wound dressing device comprises a wound dressing, including a wound VAC dressing, that has an enzymatic debriding agent applied or deposited into and/or onto its wound contacting surface prior to use of the wound dressing on a wound. The enzymatic debriding agent may be deposited on or applied to the wound contacting surface of the wound dressing by direct application, such as by sprinkling the wound contacting surface of the wound dressing with the enzymatic debriding agent, or such as by the application of an ointment containing the enzymatic debriding agent into and/or onto the wound contacting surface of the wound dressing.

(18) Preferably, the enzymatic debriding agent is collagenase.

(19) In use, the inventive wound dressing device is placed on a wound for debriding the wound in-situ. Preferably, the wound dressing device is at least sized to fit the wound base.