Sealant dressings with protected reactive components

Abstract

The present invention relates to a multilayer wound dressing having a carrier layer, at least two sublayers and a buffering salt, wherein each sublayer comprises at least one reactive crosslinkable component, at least two reactive crosslinkable components are co-reactive with one another, and at least one reactive crosslinkable component has a protective leaving group.

Description

Background Art

[0001] Absorbable hemostatic patches comprising two cross-linkable components have been described in the literature, including in U.S. Publication No. 2011 / 0045047 A1. The cross-linkable components used in such patches can be a pair of co-reactive compounds or a carrier substrate coated with a co-reactive compound having available units that can form covalent cross-links with corresponding co-reactive groups on the carrier substrate. A major limitation of such patents is that the co-reactive components can react in aqueous / humid environments, which can reduce the effectiveness of the patch over time. One practice to overcome this problem is to process and package co-reactive patches under low moisture conditions. Another practice is to create some space or separation between the co-reactive layers by applying a coating on opposite sides of the dressing or by placing a film barrier layer between the co-reactive components.

[0002] Applicants have identified an alternative approach to improve stability and efficacy in which one or more co-reactive, cross-linkable components applied to the dressing are chemically modified with a protective leaving group and delivered with a buffering salt. Summary of the Invention

[0003] The present invention relates to a multilayer wound dressing having a carrier layer, at least two sublayers, and a buffering salt, wherein each sublayer comprises at least one reactive crosslinkable component, at least two reactive crosslinkable components co-react with one another, and at least one reactive crosslinkable component has a protective leaving group. The wound dressing may have at least two separate co-reactant-containing sublayers. The carrier layer may have at least two chemically distinct layers that are structurally integrated via ultrasonic welding, needling, thermal welding, chemical attachment, suture attachment, or a combination thereof.

[0004] Substantially all of the amine groups of the at least one protected reactive cross-linkable component can be capped with a hydrohalide leaving group. In one embodiment, the at least one protected reactive group is a PEG-amine having a protective leaving group on substantially all of the primary amine groups. The protective leaving group can react with a buffer to render the primary amine groups available for reaction.

[0005] The two separate co-reactant-containing sub-layers may be provided in the form of a first layer having components that are co-reactive with groups available in the second, preferably opposing, sub-layer, said groups being co-reactive cross-linkable protecting groups.

[0006] The carrier and the two sublayers can be arranged in a stacked arrangement. In one embodiment, the carrier has three stacked sublayer coatings, each of which has a buffer, a co-reactive crosslinkable agent, and a protected co-reactive crosslinkable agent. The buffer sublayer can be immediately adjacent to the carrier layer, the protected co-reactive crosslinkable coating sublayer is adjacent to the buffer-coated sublayer, and the co-reactive crosslinkable coating sublayer is the top layer immediately adjacent to the protected co-reactive crosslinkable coating sublayer. In another embodiment, the multilayer wound dressing can have a carrier layer and a buffer-coated sublayer adjacent to the carrier layer, and a protected PEG-amine and PEG-NHS reactant-coated sublayer, the carrier layer having two discrete sublayers in a stacked arrangement, the protected PEG-amine and PEG-NHS having been co-deposited as the top layer adjacent to the buffer-coated sublayer.

[0007] The buffer can be a basic compound, and the co-reactive cross-linking agent can be PEG-NHS, and the protective co-reactive cross-linking component is a PEG-amine with multiple hydrohalide protective leaving groups. The buffer can preferably be a basic compound. In one embodiment, the buffer can be sodium borate, sodium tetraborate or disodium tetraborate, 2-(N-morpholino)ethanesulfonic acid (MES), tris(hydroxymethyl)aminomethane (TRIS), bis(2-hydroxyethyl)amino-tris(hydroxymethyl)methane (Bis-Tris), sodium carbonate, sodium bicarbonate, sodium acetate, and combinations thereof.

[0008] In one embodiment, the multi-layer wound dressing described above has been subjected to toughening to increase flexibility. In another embodiment, the wound dressing described above has been subjected to roller compression toughening.

[0009] The present invention also relates to a method of making the above multilayer wound dressing by spray coating a substrate with a layer of a co-reactive crosslinkable agent and a buffering agent. The present invention also relates to a method of treatment comprising applying the above multilayer wound dressing to tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 An embodiment of a wound dressing of the present invention is shown.

[0011] Figure 2 Graph showing tissue peel force for various samples.

[0012] Figure 3 A graph comparing peel force values ​​is shown.

[0013] Figure 4 Comparative values ​​of tissue peeling force for various buffers are shown.

[0014] Figure 5 A graph showing maximum load versus weight.

[0015] Figure 6 A graph showing the relationship between maximum load and surface topography is shown. DETAILED DESCRIPTION

[0016] The dressing of the present invention comprises a carrier layer having at least two sublayers containing a co-reactive, cross-linkable component and a buffer layer. The carrier layer may have at least two chemically distinct layers that are structurally integrated via ultrasonic welding, needling, thermal welding, chemical attachment, or suture attachment. In another alternative embodiment, the wound dressing may be provided with at least two discrete co-reactant-containing layers and combined with or delivered with a buffering saline, preferably an alkaline buffer.

[0017] The carrier substrate and substrate layer can optionally be the form of weaving, nonwoven or porous sponge material.The exemplary material of construction is cellulose, synthetic polymer, gelatin, collagen and extracellular matrix.The carrier substrate and sublayer can be made of the component of the copolymer that is selected from gelatin, collagen, oxidized polysaccharide, aliphatic polyester polymer and / or one or more monomers, and the monomer is selected from the group of being made up of the following item: D-lactic acid, L-lactic acid, lactide (comprising L-, D-, meso form), glycolic acid, glycolide, caprolactone, p-dioxanone and trimethylene carbonate and their mixture or blend. Biodegradable polyurethanes prepared using, but not limited to, diisocyanates such as ethyl 2,6-diisocyanatohexanoate (ELDI) and methyl 2,6-diisocyanatohexanoate (MLDI) together with degradable aliphatic polyester diols and degradable chain extenders such as 2-hydroxyethyl-2-hydroxypropionate, 4-((1-(1-amino-2-phenylethoxy)ethoxy)methylcyclohexyl)methyl-2-amino-3-phenylpropionate, 1,1-(hexane-1,6-diyl)bis(3-2-hydroxyethyl)urea, ethane-1,2-diylbis(3-4-hydroxyphenyl)propionate, bis(2-hydroxyethyl)phosphate, and bis(2-hydroxyhexyl)phosphate may also be suitable for preparing the substrate.

[0018] In one form, the carrier substrate is composed of a layer of oxidized polysaccharides, particularly oxidized cellulose and neutralized derivatives thereof. For example, the cellulose can be carboxyl-oxidized or aldehyde-oxidized cellulose. In one form, an oxidized regenerated polysaccharide (including but not limited to oxidized regenerated cellulose) can be used to prepare a second absorbable woven or knitted fabric. Regenerated cellulose has a higher uniformity than cellulose that has not yet been regenerated. Detailed descriptions of regenerated cellulose and how to prepare oxidized regenerated oxidized cellulose are provided in the following patents: U.S. Patent 3,364,200, U.S. Patent 5,180,398 and U.S. Patent 4,626,253, the contents of which are hereby incorporated by reference as if fully set forth. Examples of fabrics that can be used include but are not limited to Interceed absorbable adhesion barriers, Surgicel absorbable hemostats; Surgicel Nu-Knit absorbable hemostats; and Surgicel Fibrillar absorbable hemostats; each available from Ethicon, Inc., Somerville, NJ. The aforementioned Interceed absorbable adhesion barrier and methods of making the same are disclosed in US Patent No. 5,007,916, the entire disclosure of which is hereby incorporated by reference.

[0019] The carrier substrate may alternatively or additionally be composed of a layer of fabric of an aliphatic polyester polymer, copolymer, or blend thereof. Aliphatic polyesters are typically synthesized in the ring-opening polymerization of monomers including, but not limited to, lactide (including L- and D-, meso forms), glycolic acid, glycolide, caprolactone, p-dioxanone (1,4-dioxane-2-one), and trimethylene carbonate (1,3-dioxane-2-one). In some cases, aliphatic polyesters can be prepared, for example, by polycondensation of D-lactic acid, L-lactic acid, and / or glycolic acid. In one form, the fabric comprises a copolymer of glycolide and lactide in an amount of about 70 to 95 mole percent of glycolide and the remaining lactide.

[0020] The carrier substrate may also include an oxidized regenerated cellulose / polypropylene / polydioxanone (PDS) web, which is commercially available from Ethicon, Inc. under the trade name Proceed. U.S. Patent Publication Nos. 2005 / 0113849A1 and 2008 / 0071300A1 disclose the aforementioned Proceed oxidized regenerated cellulose / polypropylene / PDS web substrate and methods for making the same, the disclosures of which are hereby incorporated by reference in their entireties. In one form, both outer surfaces of the oxidized regenerated cellulose / polypropylene / PDS web may be substantially coated with the polymer coating, and in another form, only one outer surface of the substrate may be substantially coated with the polymer coating. The fabric used to form the substrate may be composed solely of an aliphatic polyester polymer, copolymer, or blend thereof, or in combination with oxidized polysaccharide fibers.

[0021] In one embodiment, the carrier substrate is made of a layer of biomaterial, and the biomaterial is selected from the group consisting of the following items: biomaterial, preferably protein, biopolymer or polysaccharide matrix, especially collagen, gelatin, fibrin, starch or chitosan matrix and their mixture. Preferably, matrix of the present invention is biodegradable, that is, it is naturally absorbed by the patient's body after a period of time. In any case, the material (including matrix) must be biocompatible, that is, there is no harmful effect on the patient of the material. This type of biodegradable material is particularly suitable for realizing the situation of hemostasis in vivo, i.e., closing the position during surgery and after surgery.

[0022] Therefore, in one embodiment, the carrier substrate is preferably a biomaterial selected from biopolymers such as proteins or polysaccharides. Particularly preferred is the biomaterial selected from the group consisting of the following items: collagen, gelatin, fibrin, polysaccharides such as hyaluronic acid, chitosan and their derivatives, more preferably gelatin, collagen and chitosan, particularly preferably gelatin and collagen. This type of gelatin or collagen matrix used for the present invention can be derived from any collagen suitable for forming a gel, including materials and particles from liquid, pasty, fibrous or powdered collagen materials that can be processed into porous or fibrous matrix. The preparation of the collagen gel used to produce sponges or sheets can include acidification until gel formation occurs and subsequent pH neutralization. In order to improve gel forming ability or solubility, collagen can be (partially) hydrolyzed or modified, as long as the characteristic of forming a stable sponge or sheet when drying is not weakened. The matrix used for coupling thrombin receptor activators can be a biopolymer, i.e., a naturally occurring polymer or its derivative, or can be a synthetic polymer. The example of the biopolymer that can be used in the hemostatic material according to the present invention includes polypeptides, such as collagen, collagen derivatives such as gelatin, elastin and elastin derivatives.

[0023] Collagen-containing embodiments according to the present disclosure include a porous carrier substrate having a first co-reactive and cross-linkable component applied to a first portion of the porous carrier substrate and a second co-reactive and cross-linkable component applied to a second portion of the porous carrier substrate.

[0024] The porous carrier substrate of the dressing has an opening or hole at at least a portion of its surface. As described in more detail below, suitable materials for forming the porous carrier substrate include but are not limited to fiber structures (e.g., knitted structures, woven structures, nonwoven structures, etc.) and / or foams (e.g., open-cell or closed-cell foams). In an embodiment, the hole may have a sufficient number and size to interconnect over the entire thickness of the porous carrier substrate. Woven fabrics, knitted fabrics, and open-cell foams are illustrative examples of structures in which the hole may have a sufficient number and size to interconnect over the entire thickness of the porous carrier substrate. In an embodiment, the hole is not interconnected over the entire thickness of the porous carrier substrate. Closed-cell foam or molten nonwoven materials are illustrative examples of structures in which the hole may not interconnect over the entire thickness of the porous carrier substrate. The hole of the foam porous substrate may span the entire thickness of the porous carrier substrate. In other embodiments, the hole does not extend through the entire thickness of the porous carrier substrate, but is present at a portion of its thickness. In an embodiment, the opening or hole is located on a portion of the surface of the porous carrier substrate, wherein the other portions of the porous carrier substrate have a non-porous texture.

[0025] In the case where the porous support substrate is fibrous, the porous support substrate can be formed using any method suitable for forming a fibrous structure, including but not limited to knitting, weaving, nonwoven technology, wet spinning, electrospinning, extrusion, coextrusion, etc. Suitable techniques for making fibrous structures are within the capabilities of those skilled in the art. In an embodiment, the textile has a three-dimensional structure, such as the textiles described in U.S. Patents 7,021,086 and 6,443,964, the disclosures of which are incorporated herein by reference in their entirety.

[0026] In an embodiment, the porous carrier substrate is made of fibers of oxidized cellulose. Such materials are known and include oxidized cellulose hemostatic materials commercially available under the trade name SURGICEL. Methods for preparing oxidized cellulose hemostatic materials are known to those skilled in the art and are disclosed, for example, in U.S. Patents 3,364,200; 4,626,253; 5,484,913; and 6,500,777, the disclosures of which are incorporated herein by reference in their entireties.

[0027] When the porous carrier substrate is a foam, the porous carrier substrate can be formed using any method suitable for forming a foam or sponge, including but not limited to lyophilization or freeze drying of the composition. The foam can be cross-linked or non-cross-linked and can include covalent bonds or ionic bonds. Suitable techniques for preparing foams are within the capabilities of those skilled in the art.

[0028] The one or more sublayers of the porous carrier substrate can be at least 0.1 cm thick, and in certain embodiments, about 0.2 cm to about 1.5 cm thick. The size of the pores in the sublayers of the porous carrier substrate can be from about 2 microns to about 300 microns, and in embodiments, from about 50 microns to about 150 microns. It is conceivable that the pores of the sublayers of the substrate can be arranged in the substrate in any manner. For example, the pores can be constructed in a random or uniform manner. In some embodiments, copper alginate can be used to form pores to produce a honeycomb-shaped porous substrate. In other embodiments, the pores can be configured to produce a gradient in the porous substrate. This gradient can further enhance the ability of the porous substrate to absorb physiological fluids and guide the physiological fluid carrying the first co-reactive component to migrate to the second co-reactive component.

[0029] In an embodiment, the dressing is made of non-denatured collagen or collagen that has at least partially lost its helical structure by heating or any other method, which is mainly composed of non-hydrolyzable α chains with a molecular weight close to 100kDa. The term "non-denatured collagen" refers to collagen that has not yet lost its helical structure. The collagen used in the dressing of the present dressing can be native collagen or decapeptide collagen, in particular obtained by pepsin digestion and / or after moderate heating as previously defined. The collagen may have been previously chemically modified by oxidation, methylation, ethylation, succinylation or any other known method. The collagen can also be cross-linked with any suitable cross-linking agent, such as genipin, isocyanates and aldehydes. The source and type of collagen can be as indicated for the non-dressing described above.

[0030] In other embodiments, gelatin or collagen (including any collagen described herein) can be used as one of the precursors. As described in more detail below, the nucleophilic amine groups on the collagen precursor can react freely with the electrophilic groups on the first co-reactive component to form the substrate of the present disclosure.

[0031] In an embodiment, the carrier substrate or its porous collagen layer can be obtained by freeze-drying an aqueous acid solution of collagen having a concentration of 2 to 50 grams per liter (g / l) and an initial temperature of 4 to 25° C. The concentration of collagen in the solution can be from about 1 g / l to about 30 g / l, in an embodiment about 10 g / l. The solution is advantageously neutralized to a pH of about 6 to 8. The dressing can also be obtained by freeze-drying a fluid foam prepared from collagen or a heated collagen solution, which solution is emulsified in the presence of a certain volume of air in variable relative amounts (air:water volume varying from about 1 to about 10).

[0032] In one embodiment, the carrier substrate has a first co-reactive component applied to the first sub-layer and a second co-reactive component applied thereto. The terms "first co-reactive component" and "second co-reactive component" each refer to a polymer, functional polymer, macromolecule, small molecule, or cross-linking agent that can react to form a cross-linked molecular network, such as a hydrogel.

[0033] In one embodiment, each of the first co-reactive component and the second co-reactive component is multifunctional, meaning that it comprises two or more electrophilic or nucleophilic functional groups, such that, for example, a nucleophilic functional group on the first co-reactive component can react with an electrophilic functional group on the second co-reactive component to form a covalent bond. At least one of the first co-reactive component or the second co-reactive component comprises two or more functional groups such that, due to an electrophilic-nucleophilic reaction, the precursors combine to form a cross-linked polymer product. Such reactions are referred to as "cross-linking reactions."

[0034] In certain embodiments, the first co-reactive component and the second co-reactive component each contain only one type of functional group, either only nucleophilic groups or only electrophilic functional groups, so long as both nucleophilic precursors and electrophilic precursors are used in the cross-linking reaction. Thus, for example, if the first co-reactive component has a nucleophilic functional group such as an amine, the second co-reactive component can have an electrophilic functional group such as N-hydroxysuccinimide. On the other hand, if the first co-reactive component has an electrophilic functional group such as sulfosuccinimide, the second co-reactive component can have a nucleophilic functional group such as an amine or a thiol. Thus, functional polymers such as proteins, poly(allylamine), styrenesulfonic acid, or amine-terminated difunctional or multifunctional poly(ethylene glycol) ("PEG") can be used.

[0035] The first and second co-reactive components can have a biologically inert and water-soluble core. When the core is a water-soluble polymer region, preferred polymers that can be used include: polyethers, for example, polyalkylene oxides such as polyethylene glycol ("PEG"), polyethylene oxide ("PEO"), polyethylene oxide-polypropylene oxide copolymers ("PPO"), polyethylene oxide block copolymers or random copolymers, and polyvinyl alcohol ("PVA"); poly(vinyl pyrrolidone) ("PVP"); poly(amino acids); polysaccharides such as dextran, chitosan, alginate, carboxymethyl cellulose, oxidized cellulose, hydroxyethyl cellulose, hydroxyethyl cellulose, hyaluronic acid; and proteins such as albumin, collagen, casein, and gelatin. Polyethers, and more particularly poly(oxyalkylene)s or poly(ethylene glycol)s or polyethylene glycols, are particularly useful. When the core is a small molecule in nature, any of a variety of hydrophilic functional groups can be used to render the first and second co-reactive components water-soluble. For example, water-soluble functional groups such as hydroxyl, amine, sulfonate, and carboxylate can be used to prepare water-soluble precursors. In addition, N-hydroxysuccinimide ("NHS") ester of suberic acid is insoluble in water, but by adding a sulfonate group to the succinimide ring, NHS ester of suberic acid can be made water-soluble without affecting its reactivity toward amine groups.

[0036] In certain embodiments, both the first co-reactive component and the second co-reactive component can be macromolecules capable of cross-linking. For example, in embodiments, one of the precursors can be a multifunctional PEG having a molecular weight of about 2,000 to about 20,000 Daltons. In embodiments having electrophilic groups, the multifunctional PEG can react with collagen having a molecular weight of about 100,000 Daltons. In other embodiments, gelatin having a molecular weight of about 50,000 to about 100,000 Daltons can be used instead of collagen.

[0037] In all embodiments, at least one of the co-reactive components has a protective leaving group and a buffer salt is provided as a sublayer. The PEG-amine can be provided, for example, in salt form (such as the chloride salt form of the PEG-amine) as a protective leaving group. Examples of preferred buffer salts are disodium tetraborate (Borax), 2-(N-morpholino)ethanesulfonic acid (MES), tris(hydroxymethyl)aminomethane (TRIS), bis(2-hydroxyethyl)amino-tris(hydroxymethyl)methane (Bis-Tris), sodium carbonate, sodium carbonate or sodium bicarbonate, sodium acetate, and combinations thereof.

[0038] In an alternative embodiment, the co-reactive component and buffer are provided on the patch. An exemplary sealing patch / gasket includes: PEG-NH2*HCl and PEG-NHS, a buffering salt, preferably as an alkaline buffer, each deposited as a layer on an absorbable substrate.

[0039] If it is desired that the biocompatible cross-linked polymer produced by the reaction of the first co-reactive component and the second co-reactive component is biodegradable or absorbable, one or more of the first co-reactive component and the second co-reactive component may have a biodegradable linker present between the functional groups. The biodegradable linker can also optionally be used as the water-soluble core of one or more precursors in the precursor. In an alternative, or in addition, the functional groups of the first co-reactive component and the second co-reactive component can be selected so that the reaction product therebetween produces a biodegradable linker. For each method, a biodegradable linker can be selected so that the resulting biodegradable biocompatible cross-linked polymer will degrade, dissolve or absorb within the desired time period. Preferably, a biodegradable linker that degrades into a non-toxic product under physiological conditions is selected.

[0040] Biodegradable linkage can be chelate or chemical or enzymatic hydrolyzable or absorbable.Exemplary chemically hydrolyzable biodegradable linkage comprises polymer, copolymer and oligomer of glycolide, d-lactide, lactide, caprolactone, dioxanone and trimethylene carbonate.Exemplary enzymatically hydrolyzable biodegradable linkage comprises peptide bond that can be cleaved by metalloproteinase and collagenase.Other exemplary biodegradable linkage comprises polymer and copolymer of poly (hydroxy acid), poly (orthocarbonate), poly (anhydride), poly (lactone), poly (amino acid), poly (carbonate), poly (sugar) and poly (phosphonate).In embodiments, biodegradable linkage can contain ester bond.Some non-limiting examples comprise ester and carboxymethyl ester of succinic acid, glutaric acid, propionic acid, adipic acid or amino acid.

[0041] In an embodiment, a multifunctional electrophilic polymer such as a multi-arm PEG functionalized with multiple NHS groups can be used as the first co-reactive component, and a multifunctional nucleophilic component such as trilysine can be used as the second co-reactive component. In other embodiments, a multifunctional electrophilic polymer such as a multi-target PEG functionalized with multiple NHS groups can be used as the first co-reactive component, and a multifunctional nucleophilic polymer such as collagen and / or a collagen derivative can be used as the second co-reactive component. The multi-arm PEG functionalized with multiple NHS groups can, for example, have four, six, or eight arms and have a molecular weight of about 5,000 to about 25,000. Many other examples of suitable first and second precursors are described in U.S. Patents 6,152,943, 6,165,201, 6,179,862, 6,514,534, 6,566,406, 6,605,294, 6,673,093, 6,703,047, 6,818,018, 7,009,034, and 7,347,850, the entire contents of each of which are incorporated herein by reference.

[0042] For patch embodiments, the co-reactive components and buffer can be deposited on the substrate as separate layers. Alternatively, the co-reactive components can be deposited as a mixture, and the buffer is provided as a separate layer. The order of the layers can vary, but the preferred order for coating a patch or spacer with PEG-NH2*HCl (or any other hydrohalide), PEG-NHS, and a buffer salt (such as disodium tetraborate, MES, TRIS, Bis-Tris, sodium bicarbonate) starts with the substrate, followed by a buffer salt layer, a protected PEG-amine layer, and a PEG-NHS layer.

[0043] Furthermore, the number of arms and the molecular weight of the material can be varied, but from the perspective of efficacy and stability, 4-arm-10K-NH2*HCl and 4-arm-10K-NHS are preferred variants. This embodiment was evaluated with different coating sequences. The position of the buffer deposited on the substrate using the spray coating process greatly affects performance and stability. Performance and stability are best when the buffer is deposited below the two PEGs (i.e., furthest from the tissue when applied to the substrate).

[0044] The first co-reactive component can be applied to the porous carrier substrate using any suitable method known to those skilled in the art, including but not limited to spraying, brushing, dipping, pouring, laminating, and the like. In embodiments, the first co-reactive component can be applied to the carrier substrate as a coating in any concentration, size, and configuration capable of forming a hemostatic dressing. In embodiments, the first co-reactive component coating can penetrate the pores of the porous carrier substrate. In embodiments, the first co-reactive component can be applied to the porous substrate as a film laminated to at least one side of the substrate.

[0045] The patch embodiment was evaluated in the presence and absence of a deposited buffer on the substrate. When 0.2M TRIS (pH = 7.4) was used as the medium during the tissue stripping test, the buffering capacity was insufficient to deprotect the PEG-NH2*HCl, resulting in poor adhesion to the tissue. When the medium was replaced with 1M sodium bicarbonate (pH = 8.3), the PEG-NH2*HCl was fully deprotected, which improved the adhesion properties compared to the standard formulation used as a control. When the buffer is provided on the substrate itself, as described in Embodiments 1 and 2, the need for sufficient pre-existing buffering capacity in the blood or body fluids is eliminated because the buffer is provided within the product.

[0046] The second co-reactive component and the buffering agent can likewise be applied to the porous substrate using any suitable method known to those skilled in the art, including but not limited to spraying, brushing, dipping, casting, laminating, and the like. In other embodiments, the second co-reactive component and the buffering agent can each be applied to the porous substrate as a solution, followed by evaporation or lyophilization of the solvent. In embodiments, the second co-reactive component and the buffering agent can each be applied to the porous substrate as a coating on at least one side of the carrier substrate or as a film laminated to at least one side of the carrier substrate.

[0047] It should be understood that as an alternative to foam collagen or gelatin, the porous carrier substrate can be a fibrous structure. Thus, in an embodiment, the porous substrate can be a fibrous structure, i.e., a woven or non-woven structure. The first co-reactive component and the second co-reactive component and the buffer can be applied to the fibrous porous carrier substrate using substantially the same techniques described above for the foam porous carrier substrate. Thus, as with the foam porous carrier substrate described above, where the porous carrier substrate is fibrous, the first and co-reactive components and / or the second co-reactive components and the buffer can be applied, for example, as particles deposited from a solution, a non-porous film formed by drying a film-forming solution, or as a foam applied to at least a portion of a fibrous porous carrier substrate.

[0048] In one embodiment, one or more sublayers include a nonwoven fabric and a reinforcing fabric. The reinforcing fabric provides a backing to which the nonwoven fabric can be attached directly or indirectly. The nonwoven fabric is used as the first absorbable nonwoven fabric of the enhanced absorbable multilayer fabric described herein. The first absorbable nonwoven fabric is composed of fibers comprising aliphatic polyester polymers, copolymers, or blends thereof. Aliphatic polyesters are typically synthesized by ring-opening polymerization of monomers, including but not limited to lactic acid, lactide (including L-, D-, meso, and D, L mixtures), glycolic acid, glycolide, ε-caprolactone, p-dioxanone (1,4-dioxane-2-one), and trimethylene carbonate (1,3-dioxane-2-one). Preferably, the first absorbable nonwoven fabric comprises a copolymer of glycolide and lactide in an amount of about 70 mol % to 95 mol % of glycolide and the remaining lactide.

[0049] In an alternative embodiment, the first absorbable nonwoven fabric comprises a combination of fibers and oxidized polysaccharide fibers made up of aliphatic polyester polymers, copolymers or their blends. Preferably, the nonwoven fabric is made by methods except spinning, weaving or knitting. For example, the nonwoven fabric can be made by yarn, scrim, netting or filaments made by methods including spinning, weaving or knitting. Yarn, scrim, netting and / or filaments are curled to enhance entanglement with each other and attachment to the second absorbable woven or knitted fabric. Such curled yarn, scrim, netting and / or filaments can then be cut into sufficiently long staple fibers for entanglement. The length of the staple fibers can be between approximately 0.1 inch and 3.0 inches, preferably between approximately 0.75 inch and 2.5 inches, most preferably between approximately 1.5 inches and 2.0 inches. The staple fibers can be combed to produce nonwoven batting, which can then be acupunctured or calendered into the first absorbable nonwoven fabric. In addition, the staple fibers can be entangled or piled up.

[0050] The thickness of the sublayer of the nonwoven fabric may be in the range of about 0.25 mm to 2 mm. The basis weight of the nonwoven fabric may be in the range of about 0.01 g / in 2 Up to 0.2g / in 2 , preferably about 0.03g / in 2 to 0.1g / in 2 and most preferably about 0.04 g / in 2 to 0.08g / in 2 The weight percentage of the first absorbable nonwoven fabric may be in the range of about 10% to 80% based on the total weight of the reinforced absorbable multi-layer fabric.

[0051] The second absorbable woven or knitted fabric serves as a reinforcing fabric and comprises an oxidized polysaccharide, particularly oxidized cellulose and neutralized derivatives thereof. For example, the cellulose may be carboxyl-oxidized or aldehyde-oxidized cellulose. More preferably, an oxidized regenerated polysaccharide, including but not limited to oxidized regenerated cellulose, may be used to prepare the second absorbable woven or knitted fabric. Regenerated cellulose is preferred because it has a higher uniformity relative to cellulose that has not yet been regenerated. Detailed descriptions of regenerated cellulose and how to prepare oxidized regenerated oxidized cellulose are provided in the following patents: U.S. Patents 3,364,200, 5,180,398, and 4,626,253, the contents of each of which are hereby incorporated herein by reference in their entirety.

[0052] The reinforcing fabric utilized in the present invention can be woven or knitted, provided that the fabric possesses the necessary physical properties for use in the envisioned application. Such fabrics are described, for example, in U.S. Patents 4,626,253, 5,002,551, and 5,007,916, the contents of which are hereby incorporated by reference as if fully set forth herein. In a preferred embodiment, the reinforcing fabric is a warp-knit tricot fabric constructed from lustrous rayon yarn that is subsequently oxidized to contain carboxyl or aldehyde moieties in an amount effective to provide the fabric with biodegradability.

[0053] In an alternative embodiment, the second absorbable woven or knitted fabric comprises oxidized polysaccharide fibers in combination with fibers comprised of aliphatic polyester polymers, copolymers, or blends thereof.

[0054] The second absorbable woven or knitted fabric preferably comprises oxidized regenerated cellulose and may have a viscosity of about 0.001 g / in 2 Up to 0.2g / in 2 range, preferably about 0.01 g / in 2 to 0.1g / in 2 range and most preferably about 0.04 g / in 2 to 0.07g / in 2 Basis weight within the range.

[0055] The first absorbable nonwoven fabric is attached directly or indirectly to the second absorbable woven or knitted fabric. For example, the nonwoven fabric can be bonded to the second absorbable woven or knitted fabric via needle punching, calendering, embossing or hydroentanglement, or chemical or thermal bonding. The short fibers of the first absorbable nonwoven fabric can be entangled with each other and embedded in the second absorbable woven or knitted fabric. More specifically, for methods other than chemical or thermal bonding, the first absorbable nonwoven fabric can be attached to the second absorbable woven or knitted fabric so that at least about 1%, preferably about 10-20%, and preferably no more than about 50% of the short fibers of the first absorbable nonwoven fabric are exposed on the other side of the second absorbable woven or knitted fabric. This ensures that the first absorbable nonwoven fabric and the second absorbable woven or knitted fabric remain joined and do not delaminate under normal handling conditions. The enhanced absorbable multilayer fabric is uniform so that substantially none of the second absorbable woven or knitted fabrics is visually lacking coverage by the first absorbable nonwoven fabric.

[0056] During use, the patch dressing is oriented to apply the co-reactive component directly to the tissue. In certain embodiments, the first co-reactive portion and the second co-reactive portion can be distinguished from each other by adding contrast dyes, surface textures, coloring or other visual cues. When in contact with tissue such as injured tissue, the dressing will absorb physiological fluids, and the first hydrogel will be dissolved by the fluid. When the liquid penetrates and migrates through the dressing, the fluid will carry the dissolved first co-reactive component into the second co-reactive component and the buffer. Ultimately, the first co-reactive component and the second co-reactive component will react to form a biocompatible cross-linked material, thereby helping the tissue to grow inward and reshape when the scaffold degrades. In some embodiments, the biocompatible cross-linked material produced by the reaction of the first co-reactive component and the second co-reactive component also provides anti-adhesion properties for the dressing.

[0057] The following examples are provided for illustrative purposes only and are not intended to limit the scope of the present disclosure.

[0058] Example 1 :

[0059] Four example deposition modes. The coating order is defined as the proximity of the layer to the carrier substrate (layer 1 closest to the carrier substrate, layer 2 second closest, etc.) and represents the order in which the materials are deposited in the spray coating process.

[0060] like Figure 1 As shown, Examples (a - first coating sequence), (b - second coating sequence) and (c - third coating sequence) demonstrate distinct deposited layers of buffer salt, protected form of PEG-amine and PEG-NHS. Example (d) shows a mixture of protected form of PEG-amine and PEG-NHS co-deposited together in a single uniform layer. For each component, these layers were applied using ultrasonic spray coating to a two-layer carrier substrate comprising an oxidized cellulose layer bonded to a fiber layer composed of a copolymer made of 90% glycolide and 10% L-lactide. At 14.2 mg / cm 2 The average coating density of 4-arm-10K-PEG-amine hydrochloride was 17.7 mg / cm 2 4-Arm-10K-PEG-SG was deposited at an average coating density of 1.0 mg / cm; and disodium tetraborate was used as a buffer in this study, with an average coating density of 1.0 mg / cm 2 .

[0061] Example 2 : Testing of tissue peeling forces of various buffer coating arrangements.

[0062] The tissue dissection force of the prototype was evaluated under progressively harsher conditions and Figure 2The least severe condition was no γ-irradiation at week 0, while the most severe condition was 40°C for 2 weeks after γ-irradiation.

[0063] Example 3: See Figure 3

[0064] Figure 2 Tissue stripping forces of various prototypes with different candidate buffers (all buffers in the first coating sequence of Example 1) (a). The tissue stripping forces of the prototypes were evaluated under increasingly harsh conditions (b). The least harsh condition was no γ-irradiation at week 0, while the most severe condition was 2 weeks at 40°C after γ-irradiation. Prior to prototype fabrication, a rough estimate of the target buffer density was made by titrating PEG-amine hydrochloride with the corresponding buffer. Using ultrasonic spraying, the components were deposited onto a double-layer carrier substrate comprising an oxidized cellulose layer bonded to a fiber layer composed of a copolymer made of 90% glycolide and 10% L-lactide. The corresponding buffer (e.g., Bis-Tris, sodium acetate, etc.) was first deposited onto the carrier substrate, with an average coating density of Bis-Tris of 2.2 mg / cm 2 , sodium acetate is 2.0 mg / cm2, sodium bicarbonate is 1.2 mg / cm2, MES sodium is 2.2 mg / cm 2 , disodium tetraborate is 0.8 mg / cm 2 , Tris is 0.5 mg / cm 2 After the indicated buffer, 4-arm-10K-PEG-amine hydrochloride (at 12 mg / cm 2 ) and 4-arm-10K-PEG-SG (at 18 mg / cm 2 ) were sequentially coated onto a carrier substrate. For the Bis-Tris and sodium bicarbonate prototypes, unirradiated data for week 0 were not available. The standard S1 reference line at 200 N / m corresponds to typical results from tissue peel force measurements, while the 'SOA' reference line at 40 N / m corresponds to the tissue peel force of a commercial topical hemostatic product consisting of an absorbable backing (made of oxidized cellulose) and a pair of chemically unprotected self-adhesive hydrogel components. The S1 patch corresponds to a standard formulation in which the co-reactive cross-linkable component is unprotected and no buffer is provided.

[0065] Example 4 :

[0066] Tissue stripping results of layer-by-layer (LbL) and mixed-layer (ML) prototypes with different buffer materials are shown in Figure 4All prototypes were made with the buffer in the first coating order. All results are from t=0. Using ultrasonic spraying, the components were deposited onto a two-layer carrier substrate comprising an oxidized cellulose layer bonded to a fiber layer composed of a copolymer made of 90% glycolide and 10% L-lactide. The buffers were first deposited onto their respective carrier substrates, with a target coating density of 1.9 mg / cm for Bis-Tris. 2 , sodium bicarbonate is 2.4 mg / cm 2 , disodium tetraborate is 1.1 mg / cm 2 After the indicated buffer, 4-Arm-10K-PEG-amine hydrochloride (at 7 mg / cm 2 ) and 4-arm-10K-PEG-SG (at 7.8 mg / cm 2 ) is applied as a layer onto a carrier substrate.

[0067] When using sonic spraying technology to coat matrix materials (such as the matrix manufactured by oxidized regenerated cellulose (ORC) and poly(lactide) (polyglactin) 90:10 (PG910)), the resulting matrix becomes significantly harder than uncoated matrix. This feature is undesirable during clinical application because it can not be fully covered around the uneven organ surface and accordingly can not produce the best seal of tissue surface. In order to solve this problem, the matrix coated is toughened. Toughening is achieved by using a metal roller to compress. This gives the larger pliability of the matrix material coated. In addition, it is important to increase pliability and not remove the coating material while maintaining coating density, friability and efficacy.

[0068] Example 5: Increasing the Flexibility of a Coated Hardened Substrate Matrix .

[0069] A method for increasing the toughness of a planar substrate matrix (e.g., ORC+ fibers composed of a copolymer made of 90% glycolide and 10% L-lactide) sprayed with one or more PEG compositions (e.g., PEG-NH2 + PEG-NHS) comprises the step of compressing the sprayed substrate matrix with a metal roller.

[0070] PEG-NHS-10K (18 mg / cm 2 )4-arm and PEG-NH2-5K (7.5 mg / cm 2) 4 arms were coated with a carrier substrate matrix made of an ORC+poly(lactide-coated) 90:10 matrix. This coated matrix was found to be effective in animal models. However, the same coated matrix structure was not easily conformable to irregular tissue surfaces after being coated with the PEG material. A sample of the coated matrix material was then compressed against a flat metal surface using a metal roller. This improved coated matrix material was then used, demonstrating significant improvement in conformability to irregular tissue surfaces.

[0071] program :

[0072] 1. Obtain four 2" x 4" sections of coated matrix material - test specimens.

[0073] 2. Apply pressure by rolling a cylindrical stainless steel on the coated side of the test sample or by compressing directly on it, with the rolling direction along the length of the sample. The rolling is different for each sample (conditions are as follows: A, B and D).

[0074] A: Roll a cylindrical stainless steel weight with a mass of 885 grams back and forth three times along the length of the sample (three round trips).

[0075] B: Roll a cylindrical stainless steel weight with a mass of 5650 grams back and forth once along the length of the sample (one round trip).

[0076] D: Apply pressure directly to the surface of the sample with a weight of 5650 grams for about 3 seconds.

[0077] Condition A - Control and Compression had the smallest difference in deflection, less than 5 degrees.

[0078] Condition B - Control had the greatest degree of deflection difference, approximately 30 degrees.

[0079] Condition D - Control had a moderate degree of deflection difference, 7 degrees.

[0080] Example 6 :

[0081] PEG-NHS-10K (18 mg / cm 2 )4-arm and PEG-NH2-5K (7.5 mg / cm 2 ) 4-arm coating of a carrier substrate made of an ORC + poly(lactic acid) 90:10 matrix. The effects of different roller contact surface designs (square knobs, longitudinal knobs, and no knobs considered a flat surface) were investigated using different deadweights (900 g, 5650 g, and 8190 g). Sample Information: Matrix with 4-arm PEG-NH2-5K / PEG-NHS-10K as described above.

[0082] program :

[0083] 1. Obtain four 2" x 4" sections of coated matrix material - test specimens.

[0084] 2. Weigh each 2" x 4" sample and record it as "Front Weight"

[0085] 3. Apply pressure by rolling a cylindrical stainless steel coated with a printed polymer layer on its surface on the coated side of the test sample in combination with a weight designed as in Table 1, with the rolling direction along the length of the sample.

[0086] 4. Reweigh the sample and record it as the "final weight"

[0087] The samples were tested in 3-point bending to quantify flexibility.

[0088] Sequence number System weight (g) Weight level Surface morphology 1 5650 middle Square knob 2 NA comparison NA 3 900 Low Vertical knob 4 900 Low No knob 5 8190 high No knob 6 5650 middle No knob 7 8190 high Vertical knob 8 8190 high Square knob 9 900 Low Square knob 10 5650 middle Vertical knob

[0089] Table 1.(2 3 )DOE design, factors: weight (3) and surface type (3)

[0090] Friability was measured using the weights recorded before and after application of the weight roller.

[0091]

[0092] The results showed that this procedure caused minimal friability, and therefore most of the reactive material remained on the sample using this toughening method.

[0093] Example 7: Quantifying Flexibility Using a 3-Point Bend Test

[0094] Pressure affects flexibility: Figure 5 The results shown in demonstrate that when a 900 gram weight was used to roll the coated side of the sample three times, flexibility was significantly improved compared to the control. When 5650 grams of metal was used to roll the coated side of the sample one time, the flexibility of the coated substrate increased significantly, even exceeding the flexibility of 900 grams. However, when 8190 grams of metal was used to roll the coated side of the sample, the resulting substrate flexibility was not significantly different from the 5650 gram flexibility, indicating that flexibility had plateaued.

[0095] The surface topography of the roller weighted surface has no significant effect on flexibility. It was found that the minimum 900 grams used significantly improved the flexibility of the sample compared to the control, and the applied weight of 5650 grams produced a significantly more flexible sample when compared to 900 grams. When compared to 5650 grams, applying a higher weight (8190 grams) did not produce higher test sample flexibility. In short, the results prove that 900 grams to 5650 grams is the range in which these test materials can be effectively toughened for the test materials. However, the results show that the surface topography design explored has no significant effect on the flexibility of the test samples. It should be noted that for different knob topologies, the contact surface of the roller is SLA, while without the knob set, the contact surface is metal.

[0096] Example 8

[0097] The support matrix material was coated with 4-arm-10K PEG-NH2*HCl and 4-arm-10K PEG-NHS using ultrasonic spray coating technology ( Figure 1 (First coating sequence a)) such as a matrix made of oxidized regenerated cellulose (ORC) and poly (lactide-coated glycol) 90:10. The samples were processed using the same procedure as described in Example 1, with the contact surfaces being metal. Sample information: Amine salt matrix with PEG-NH2.HCL-10K + PEG-NHS-10K + disodium tetraborate sprayed first and unbuffered matrix / 4-arm PEG-NH2 / 4-arm PEG-SG-10K as described above

[0098]

[0099] Note:

[0100] 1. Apply all pressure on the reactive coated side (when present).

[0101] 2. One round trip refers to rolling back and forth along the length of the sample (one round trip).

[0102] program:

[0103] 1. Weigh each sample and record the weight as the "Before Weight."

[0104] 2. Take a photo of the control sample - the "before photo"

[0105] 3. Apply weight by rolling

[0106] 4. Weigh the sample and record the weight as the "final weight"

[0107] The qualitative results of this example show that the minimum weight required to achieve the flexibility result is 5650 grams for the amine salt (B) formulation, while only 900 grams of weight is sufficient to toughen the non-amine formulation by rolling back and forth 3 times, as shown in Experiment 2.

[0108] For both formulations (B and H), the increase in flexibility of the test samples produced by rolling a 5650 gram weight back and forth on the coated side was similarly observed with similar deflection angles for both amine salt and non-amine salt samples.

[0109] Toughening of samples from both formulations was achieved with minimal loss of reactive powder. However, the SOA wound dressing could not be toughened using the same procedure. When the flexibility of the test samples was further analyzed using 3-point bending, the results are as follows.

[0110] Sample No. Sample conditions AVG(N) STDV A Protected amine salt - Roll 3 times with 885g 0.4690 0.0452 B Protected amine salts - 1 round trip with 5650g 0.4033 0.0163 C Protected amine salt - control (no pressure applied) 0.6006 0.0803 D Protected amine salts - 1 round trip with 2540g 0.4881 0.0626 E Protected amine salt - compressed once directly with 5650g 0.5505 0.0466 F Comparison-SOA 1.1535 0.0714 G SOA - 6 round trips with 5650g 1.0170 0.3049 H S1 - 1 round trip with 5650g 0.3432 0.0327

[0111] Grouping information using Tukey's method and 95% confidence level

[0112] sample N average value Grouping F 4 1.1535 a G 4 1.0170 b C 5 0.6006 c E 5 0.5505 c d D 5 0.4881 d e A 5 0.4690 d e B 5 0.4033 e f H 5 0.3432 f

[0113] Means that do not share a letter are significantly different.

[0114] Based on the 3-point bending results, the following conclusions can be drawn:

[0115] 1. The 885 gram weight significantly increased the flexibility by rolling it back and forth 3 times on the coated side of the sample (Sample A) compared to the control (Sample C). This result indicates that 885 grams 3 times back and forth is sufficient to toughen the sample.

[0116] 2. Compared to rolling 5650 grams back and forth for 1 round trip (Sample B), rolling 885 grams back and forth 3 times on the coated side of the sample (Sample A) did not increase flexibility. This result shows that similar flexibility can be achieved with 885 grams for 3 round trips and 5650 grams for 1 round trip, and the flexibility achieved is significantly higher than the flexibility of the control (Sample C).

[0117] 3. A 2540 gram weight passed 1 way back and forth on the coated side of the sample (Sample D) significantly increased flexibility compared to the control (Sample C).

[0118] 4. Increasing the weight of the metal cylinder from 2540 g (sample D) to 5650 g (sample B) significantly increased the flexibility of the sample.

[0119] 5. The flexibility of the sample compressed directly with 5650 grams (Sample E) was significantly lower than the flexibility of the sample rolled 1 round trip with a 5650 gram weight (Sample B).

[0120] 6. Direct compression with a 5650 g weight (Sample E) was similar to the control (Sample C).

[0121] 7. The SOA sample was compressed by a roller with a 5650 gram weight for 6 passes similar to the SOA control. Samples B and H toughened using the 5650 gram weight were comparable.

Claims

1. A multi-layer hemostatic wound dressing comprising a carrier layer, wherein the carrier substrate is composed of an oxidized cellulose layer and a copolymer fabric layer of glycolide and lactide; a sublayer coating having PEG-NHS as a co-reactive cross-linking agent; a sublayer coating having protected PEG-amine as a protective co-reactive cross-linkable component; as well as a sub-layer coating having a buffer, wherein the buffer is disodium tetraborate, wherein the sub-layer coating having a buffer is immediately adjacent to the carrier layer, the sub-layer coating having a protected PEG-amine is adjacent to the sub-layer coating having a buffer, and the sub-layer coating having PEG-NHS is a top layer immediately adjacent to the sub-layer coating having a protected PEG-amine; and The hemostatic wound dressing is a patch.

2. The multilayer hemostatic wound dressing of claim 1 , wherein the carrier layer has at least two chemically distinct layers that are structurally integrated via ultrasonic welding, needling, thermal welding, chemical attachment, suture attachment, or a combination thereof.

3. The multilayered hemostatic wound dressing of claim 1, wherein substantially all of the amine groups of the protected PEG-amine are capped with a hydrohalide leaving group.

4. The multilayered hemostatic wound dressing of claim 3, wherein the protected PEG-amine is a PEG-amine having protective leaving groups on substantially all primary amine groups.

5. The multilayer hemostatic wound dressing of claim 4, wherein the protective leaving group is reacted with a buffer to render the primary amine group available for reaction.

6. The multilayer hemostatic wound dressing of claim 1, wherein the carrier layer has a sublayer comprising a copolymer of glycolide and lactide and a sublayer comprising oxidized cellulose.

7. The multi-layer hemostatic wound dressing of claim 1 which has been toughened to increase flexibility.

8. The multilayer hemostatic wound dressing of claim 7, wherein the wound dressing is toughened by roller compression.

9. A method of making the multilayer hemostatic wound dressing of claim 1 by spray coating a substrate with a layer of a co-reactive cross-linkable agent and a buffering agent.

10. Use of the multilayer hemostatic wound dressing according to claim 1 in preparing a hemostatic product for treating tissue.

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