CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit, under 35 USC § 119(e), of the filing of U.S. Provisional Patent Application 62/584,010, titled "MULTILAYERED PRIMARY CONTACT WOUND DRESSING," filed November 9, 2017. This provisional application is incorporated herein by reference for all purposes.

BACKGROUND OF THE DISCLOSURE

[0002] When wound dressings are used for extended periods of time, tissue can ingress into the wound dressing. The ingressed tissue can adhere the wound dressing to the wound bed, making it difficult and painful to remove the wound dressing. To combat tissue ingress, wound dressings can be replaced regularly before the tissue has the opportunity to ingress into the wound dressing. However, frequent changing of the wound dressing can disrupt the tissue of the wound bed and also lead to patient discomfort.

SUMMARY OF THE DISCLOSURE

[0003] According to an aspect of the disclosure, a wound contact dressing can include a first bioresorbable sponge. The first bioresorbable sponge can be configured to degrade over a first predetermined amount of time. The first bioresorbable sponge can include a first plurality of fluid channels through the first bioresorbable sponge. The wound contact dressing can include a first collagen-based film substantially covering a first face of the first bioresorbable sponge. The first collagen-based film can line an internal wall of each of the first plurality of fluid channels. The wound contact dressing can include a second bioresorbable sponge. The second bioresorbable sponge can be configured to degrade over a second predetermined amount of time. The second bioresorbable sponge can include a second plurality of fluid channels through the second bioresorbable sponge. The wound contact dressing can include a second collagen-based film between the first bioresorbable sponge and the second bioresorbable sponge. The second collagen-based film can substantially cover a first face of the second bioresorbable sponge and line an internal wall of each of the second plurality of fluid channels. The wound contact dressing can include a third collagen-based film substantially covering a second face of the second bioresorbable sponge.

[0004] In some implementations, the first bioresorbable sponge and the second

bioresorbable sponge can include freeze-dried collagen. The first bioresorbable sponge and the second bioresorbable sponge can include about 55% collagen and about 45% oxidized regenerated cellulose by weight. The first bioresorbable sponge and the second bioresorbable sponge can include about 55% collagen, about 44% oxidized regenerated cellulose (ORC), and about 1 % silver-ORC by weight.

[0005] In some implementations, the second collagen-based film substantially covers a second face of the first bioresorbable sponge. The first collagen-based film, the second collagen-based film, and the third collagen-based film can include at least one of a high- density collagen film or a cross-linked collagen film.

[0006] In some implementations, each of the first plurality of fluid channels and the second plurality of channels are configured to enable fluid flow from a wound site to a secondary dressing.

[0007] In some implementations, the first predetermined amount of time is different than the second predetermined amount of time. The first bioresorbable sponge can include a higher collagen density than the second bioresorbable sponge. The first bioresorbable sponge can be a wound-facing layer and the second bioresorbable sponge is an environment-facing layer.

[0008] In some implementations, the first bioresorbable sponge can include an

antimicrobial agent and the second bioresorbable sponge does not comprise the antimicrobial agent. In some implementations, the second bioresorbable sponge can include an antiinflammatory agent. In some implementations, the first bioresorbable sponge and the second bioresorbable sponge can include at least one of an anti-oxidant or an analgesic. The first bioresorbable sponge can include at least one of polyhexamethylene biguanide, citric acid, silver, silver-ORC, or iodine.

[0009] In some implementations, the first collagen-based film, the second collagen-based film, and the third collagen-based film can include a plasticizer. In some implementations, the first collagen-based film, the second collagen-based film, and the third collagen-based film can degrade over a third predetermined amount of time. The third predetermined amount of time can be greater than the first predetermined amount of time and the second predetermined amount of time.

[0010] In some implementations, the wound contact dressing can include a non-resorbable backing layer that can be coupled with the third collagen-based film.

[0011] According to an aspect of the disclosure, a wound dressing can include a backing layer that has a first environment-facing side and a first wound-facing side. The backing layer can be liquid impermeable and vapor permeable. The wound dressing can include a first collagen-based sponge layer that can be coupled with the backing layer. The first collagen-based sponge layer can include a first plurality of fluid channels. The wound dressing can include a first film layer substantially covering a wound-facing side of the first collagen-based sponge layer. The wound dressing can include a second collagen-based sponge layer coupled with the first film layer. The second collagen-based sponge layer can include a second plurality of fluid channels. The wound dressing can include a second film layer substantially covering a wound-facing side of the second collagen-based sponge layer.

[0012] In some implementations, the first film layer substantially covers an inner wall of each of the first plurality of fluid channels and the second film layer substantially covers an inner wall of each of the second plurality of fluid channels. The first film layer and the second film layer can include at least one of a high-density collagen film or a cross-linked collagen film.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are not intended to be drawn to scale. Like reference numbers and designations in the various drawings indicate like elements. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

[0014] FIG. 1 illustrates a top view of an example wound dressing.

[0015] FIG. 2 illustrates a cross-sectional view of the example wound dressing illustrated in FIG. 1.

[0016] FIG. 3 illustrates an enlarged view of a fluid channel illustrated in FIG. 2.

[0017] FIG. 4 illustrates a cross-sectional view of a wound dressing placed in a wound bed.

DETAILED DESCRIPTION

[0018] In the drawings, like reference characters generally refer to like features, functionally similar elements, and/or structurally similar elements throughout the various drawings. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the teachings. The drawings are not intended to limit the scope of the present teachings in any way.

[0019] The disclosure describes a wound dressing. The wound dressing can be a bioresorbable primary contact layer dressing designed to sit between the wound bed and a secondary dressing or other material. The wound dressing can be a multi-layered dressing that can include one or more layers of a collagen-based film and a bioresorbable material, such as collagen. The wound dressing can also include a plurality of fluid channels that can pass through the wound dressing and enable exudate to flow through the channels and away from the wound bed.

[0020] Adhesion of a secondary dressing can cause patient discomfort. Tissue ingress into the secondary dressing can also cause patient discomfort. To reduce tissue ingress, dressings can often be changed regularly before tissue has the opportunity to ingress into the dressing. The wound dressing of the present disclosure can reduce wound bed adhesion of the wound dressing itself or a secondary dressing to the wound bed. The wound dressing of the present disclosure can also limit tissue ingress into the secondary dressing. The present wound dressing can limit adhesion and tissue ingress by providing a bioresorbable matrix between the wound bed and the secondary dressing. The bioresorbable wound dressing provides a spacing between the secondary dressing and is absorbed by the patient's body over time. Because the patient's body absorbs the wound dressing, the wound dressing does not need to be removed. This can reduce tissue disruption and patient discomfort.

[0021] FIG. 1 illustrates a top view of an example wound dressing 100. The wound dressing 100 can be a bioresorbable primary contact layer dressing that is configured for extended wear time. The wound dressing 100 includes multiple layers of bioresorbable sponge 102 that are each encloses in a film 104. In some implementations, the film 104 is a collagen-based film. The wound dressing 100 includes a plurality of fluid channels 106 that run through the layers of the wound dressing 100.

[0022] The wound dressing 100 can be a bioresorbable primary contact layer dressing configured to sit between the wound bed and a secondary dressing. The wound dressing 100 can provide protection against tissue ingress into the secondary dressing. In some implementations, the bioresorbable nature of the wound dressing 100 enables the wound dressing 100 to be left in place until substantially dissolved. Once dissolved, a new wound dressing 100 can be applied to the wound bed.

[0023] The bioresorbable sponge 102 included in wound dressing 100 can include a fireeze- dried collagen. In some implementations, the bioresorbable sponge 102 can include oxidized regenerated cellulose (ORC). The bioresorbable sponge 102 can include between about 30% and about 70%, between about 40% and about 60%, or between about 50% collagen by weight. In some implementations, the bioresorbable sponge 102 can include between about 30% and about 70%, between about 40% and about 60%, or between about 40% and about 50% ORC by weight. In some implementations, the bioresorbable sponge 102 can include about 55% collagen by weight and about 45% ORC by weight.

[0024] In some implementations, the bioresorbable sponge 102 can include an

antimicrobial agent. Example antimicrobial agents can include polyhexamethylene biguanide (PHMB), citric acid, silver, iodine, silver-ORC, or any combination thereof. In some implementations, the bioresorbable sponge 102 can include between about 1 % and about 10%, between about 1% and about 5%, or between about 1 % and about 3% of antimicrobial material by weight. In some implementations, the bioresorbable sponge 102 can include chitosan or gelatine. The bioresorbable sponge 102 can include one or more types of agents. The types of agents can include one or more of an anti-inflammatory agent, anti-oxidant agent, analgesic agent, or any combination thereof. In some implementations, different bioresorbable sponges 102 can include different agents or different levels of agents. For example, only a portion of the bioresorbable sponges 102 may contain an antimicrobial (e.g., the bioresorbable sponge 102 from every other layer 108) to reduce the chance of causing cytotoxicity.

[0025] The wound dressing 100 can include multiple layers of film 104. Each

bioresorbable sponge 102 can be enclosed in a layer of the film 104. The film 104 can substantially cover each of bioresorbable sponges' faces. For example, the film 104 can form a barrier between the bioresorbable sponges 102 and the extemal environment. The film 104 can protect the bioresorbable sponges 102 from enzymatic degradation. In some

implementations, the film 104 can withstand enzymatic degradation for a longer time period when compared to the bioresorbable sponge 102. In some implementations, as the enzymes break down the collagen of the wound dressing 100, the enzymes are no longer available to break down the wound bed. The film 104 can cover the internal walls defined by the fluid channels 106 that pass through the layers of the wound dressing 100. The film 104 can be a high-density collagen film. In some implementations, the film 104 can be a cross-linked collagen film. In some implementations, the film 104 is between about 10 μιτι and about 300 μιτι, between about 100 μιτι and about 300 μιτι, or between about 200 μιτι and about 300 μιτι.

[0026] The wound dressing 100 can include a plurality of fluid channels 106. The fluid channels 106 can pass through the structures of the wound dressing 100 and are illustrated further in FIGS. 2 and 3. The fluid channels 106 enable wound exudate to flow through the wound dressing 100 and can reduce the contact of the wound dressing 100 with the wound bed. In some implementations, the fluid channels 106 can have a diameter between about 0.5 mm and about 5 mm, between about 0.5 mm and about 4 mm, between about 1 mm and about 3 mm, or between about 1 mm and about 2 mm. In some implementations, neighboring fluid channels 106 can be separated by between about 1 mm and about 15 mm, between about 5 mm and about 15 mm, or between about 10 and about 15 mm.

[0027] FIG. 2 illustrates a cross-sectional view of the example wound dressing 100 illustrated in FIG. 1. FIG. 2 illustrates the cross-section of the wound dressing 100 made at the cut line A, illustrated in FIG. 1. The cut line A passes through a row of fluid channels 106.

[0028] As illustrated, the wound dressing 100 includes three layers 108. Each of the layers 108 include at least one bioresorbable sponge 102 and at least one layer of film 104. Each of the layers 108 are configured to degrade over a predetermined amount of time. The wound dressing 100 can degrade over about 7 days to 21 days. In some implementations, the wound dressing 100 can include a layered partem that alternates between layers of bioresorbable sponge 102 and film 104. In some implementations, each of bioresorbable sponges 102 can degrade over substantially the same length of time. In some implementations, each of the bioresorbable sponges 102 can be configured to degrade at a different rate. For example, the bioresorbable sponges 102 can degrade over a length of time between about 1 and about 14 days or between about 7 and 14 days.

[0029] The wound dressing 100 can have an alternating layer construction. For example, each layer 108 can include a bioresorbable sponge 102 and at least one layer of film 104. The layers 108 can be stacked to form the wound dressing 100. In some implementations, the wound dressing 100 can include between about 1 and about 10 layers 108, between about 1 and about 8 layers 108, between about 1 and about 6 layers 108, or between about 1 and about 4 layers 108.

[0030] In some implementations, each of the layers 108 can include about 1 , 2, 3, 4, or 5 bioresorbable sponges 102 that are not separated by a layer of film 104. For example, each of the layers 108 can include a different number of bioresorbable sponges 102 such that the layers 108 degrade a different rates (e.g., a layer 108 with relatively more bioresorbable sponges 102 can take relatively longer to degrade). Each layer 108 can be between about 1 mm and about 10 mm thick, between about 3 mm and about 8 mm thick, or between about 3 mm and about 6 mm thick.

[0031] The perimeters of the multiple layers 108 (e.g., the portions of the film 104 that overhang the bioresorbable sponges 102) can be fused together to form a laminated edge 1 10. The layers 108 can be fused together at the laminated edge 1 10 by applying pressure and heat to the perimeters of the layers 108. In some implementations, a bonding agent can be used to fuse the layers 108 together to form the laminated edge 110.

[0032] FIG. 3 illustrates an enlarged view of a fluid channel 106 illustrated in FIG. 2. The fluid channel 106 can pass through each of the layers 108 and enable fluid flow from the wound facing side of the device toward the environment facing side of the wound dressing 100. For example, each layer 108 can include a portion of the fluid channels' total length. The portions of the fluid channel 106 from each of the layers 108 are aligned to form the fluid channel 106 through the wound dressing 100. The film 104 can line the internal wall or face of the fluid channels 106. [0033] In some implementations, the fluid channels 106 are formed by perforating the wound dressing 100 with a cutting die that punctures the wound dressing 100 at

predetermined locations. The cutting die can stretch portions of the film 104 into the lumen of the fluid channel 106. The film 104 can stick to, and line, the internal walls of the fluid channels 106. The stretch of the film 104 can be controlled by the level of plasticizer included in the film 104. The plasticizer can be glycerol. The plasticizer can be included in the slurry mixture used to form the film 104 at a concentration of between about 0.1% to about 1%, between about 0.1% and about 0.8%, or between about 0.1% and about 0.5%.

[0034] FIG. 4 illustrates a cross-sectional view of a wound dressing 100 placed in a wound bed 400. The wound dressing 100 includes a backing layer 402 coupled with an

environment-facing side 404. Fluid flow 406 can pass from the wound bed 400 towards the backing layer 402. In some implementations, the backing layer 402 can be a secondary dressing.

[0035] The backing layer 402 can be a liquid impermeable layer. The backing layer 402 can be vapor permeable. The backing layer 402 can be impermeable to wound exudate or other wound fluids. The backing layer 402 can provide a barrier to the passage of microorganisms, bacteria, and other contaminants through the wound dressing 100 to the wound bed 400.

[0036] In some implementations, the backing layer 402 is a component of the wound dressing 100. The backing layer 402 can be a thin layer of polyurethane film. For example, the backing layer 402 can include the polyurethane film ESTANE 5714F. The backing layer 402 can include poly alkoxyalkyl acrylates and methacrylates. In some implementations, the backing layer 402 includes a continuous layer of a high-density blocked polyurethane foam that is predominantly closed-cell. The backing layer 402 can have a thickness between about 10 μηι and about 100 μιτι, between about 25 μηι and about 75 μιτι, or between about 50 μηι and about 75 μηι.

[0037] The backing layer 402 can extend beyond the perimeter of the wound dressing 100. The backing layer's wound-facing side can be coated with an acrylic or other adhesive. The adhesive can couple with the patient's skin or other surface during wear time. In some implementations, the environment-facing side 404 can include a tacky adhesive that couples with the backing layer 402 when the backing layer 402 is pressed against the wound dressing 100. The adhesive applied to the environment-facing side 404 can be moisture vapor transmitting. The application of the adhesive can be patterned to enable the passage of water vapor through the backing layer 402. The adhesive may include a continuous moisture vapor transmitting, pressure-sensitive adhesive layer of the type used for island-type wound dressings (e.g., a polyurethane-based pressure sensitive adhesive). One example of an adhesive which can be used is a pressure-sensitive adhesive based on acrylate ester copolymers, polyvinyl ethyl ether, and polyurethane.

[0038] In some implementations, the wound dressing 100 described herein can be used in negative-pressure wound therapy (NPWT). For example, and also referring to FIG. 4, a vacuum can be used to generate a negative (or reduced) pressure in the space between the wound bed 400 and the backing layer 402. The wound dressing 100 can ensure that as the negative pressure is applied to the wound, the backing layer 402 does not come into contact with the wound bed 400.

[0039] In some implementations, the wound dressing 100 described herein can be a component of a kit. The kit can include any wound dressing described herein and instructions for use. The kit can include instructions for treating a wound in a subject in need thereof. The kit can include antiseptic wipes, ointment, adhesive tape, tweezers, scissors, or other devices or components for the placement or removal of the wound dressing from a subject.

[0040] Having now described some illustrative implementations, it is apparent that the foregoing is illustrative and not limiting, having been presented by way of example. In particular, although many of the examples presented herein involve specific combinations of method acts or system elements, those acts and those elements may be combined in other ways to accomplish the same objectives. Acts, elements, and features discussed in connection with one implementation are not intended to be excluded from a similar role in other implementations or implementations.

[0041] As used herein, the term "about" and "substantially" will be understood by persons of ordinary skill in the art and will vary to some extent depending upon the context in which it is used. If there are uses of the term which are not clear to persons of ordinary skill in the art given the context in which it is used, "about" will mean up to plus or minus 10% of the particular term.

[0042] Where technical features in the drawings, detailed description, or any claim are followed by reference signs, the reference signs have been included to increase the intelligibility of the drawings, detailed description, and claims. Accordingly, neither the reference signs nor their absence have any limiting effect on the scope of any claim elements.

[0043] The systems and methods described herein may be embodied in other specific forms without departing from the characteristics thereof. The foregoing implementations are illustrative rather than limiting of the described systems and methods. Scope of the systems and methods described herein is thus indicated by the appended claims, rather than the foregoing description, and changes that come within the meaning and range of equivalency of the claims are embraced therein.