Bioabsorbable Encapsulating Powder

Abstract

The present invention provides a bioabsorbable encapsulating powder, comprising: (a) a water-soluble electrophilic polymer having at least three reactive electrophilic groups capable of reacting with amine groups under the formation of covalent bonds; (b) a water-soluble nucleophilic crosslinker having at least two reactive nucleophilic groups capable of reacting in the presence of water with a reactive electrophilic group of the electrophilic polymer under formation of a covalent bond between the electrophilic polymer and the nucleophilic crosslinker; (c) water-absorbing particles comprising at least 50% by weight of the water-absorbing particles of a water-insoluble polymer comprising reactive nucleophilic groups; (d) a water-soluble dispersing agent that is solid at 20° C. and is selected from monosaccharides, disaccharides, oligosaccharides, sugar alcohols, and combinations thereof. Components (a), (b), (c) and (d) relate to a bioabsorbable encapsulating powder which may be contained in the same particle or in different particles. The present invention also provides a method for preparing the bioabsorbable encapsulating powder. Further provided are (i) an apparatus for applying a powder comprising a bioabsorbable sealant powder, (ii) a biocompatible, flexible hemostatic sheet comprising a bioabsorbable sealant powder, and (iii) a kit of parts for preparing a sealant suspension, the kit comprising a bioabsorbable powder, and (iv) a sealant suspension containing the bioabsorbable sealant powder.

Description

[Technical field]

[0001] The present invention relates to (a) a water-soluble electrophilic polymer having at least three reactive electrophilic groups capable of reacting with amine groups under the formation of covalent bonds; (b) a water-soluble nucleophilic crosslinker having at least two reactive nucleophilic groups capable of reacting in the presence of water with a reactive electrophilic group of the electrophilic polymer under formation of a covalent bond between the electrophilic polymer and the nucleophilic crosslinker; (c) water-absorbing particles, the water-absorbing particles comprising at least 50% by weight of the water-absorbing particles of a water-insoluble polymer containing reactive nucleophilic groups selected from amine groups and thiol groups; (d) a water-soluble dispersing agent that is solid at 20° C. and is selected from monosaccharides, disaccharides, oligosaccharides, sugar alcohols, and combinations thereof; The bioabsorbable encapsulating powder comprises components (a), (b), (c) and (d) which may be contained in the same particle or in different particles.

[0002] When the sealing powder of the present invention is applied to moist tissue, the reactive components in the powder react rapidly in the formation of a tissue adhesive hydrogel that seals the underlying tissue, providing a seal that is strong enough to provide an effective seal against pulmonary air leaks. [Background technology]

[0003] Hemostasis is a tightly regulated process that maintains blood flow through the vascular system while simultaneously generating a thrombotic response to tissue injury. Maintaining hemostasis requires a complex interplay between the vessel wall, platelets, and the coagulation and fibrinolytic systems. There are two main phases of hemostasis: primary (i.e., cellular phase) and secondary (i.e., humoral phase).

[0004] Primary hemostasis begins immediately after endothelial disruption and is characterized by vasoconstriction, platelet adhesion, and the formation of a soft aggregate plug. After injury occurs, a transient localized contraction of vascular smooth muscle occurs, slowing blood flow and promoting platelet adhesion and activation. Within 20 seconds of injury, circulating von Willebrand factor deposits on the subendothelium at the site of injury and attaches to glycoproteins on the surface of platelets. Once attached to the injured surface, platelets are activated by contact with exposed collagen receptors that bind to circulating fibrinogen. A soft plug of aggregated platelets and fibrinogen is formed. This stage of hemostasis is brief, and the soft plug can be easily sheared away from the injured surface.

[0005] The soft platelet plug is stabilized during secondary hemostasis to form a clot. Vasoconstriction and the resulting reduction in blood flow are maintained by platelet secretion of serotonin, prostaglandins, and thromboxanes during the initiation of the coagulation cascade. The coagulation cascade is a series of dependent reactions involving several plasma proteins, calcium ions, and platelets that result in the conversion of fibrinogen to fibrin. Coagulation factors are produced by the liver and circulate in an inactive form until the coagulation cascade is initiated. Each step of the cascade is then initiated and completed through a series of sequential and dependent coagulation factor activation reactions. In the final step, thrombin converts fibrinogen, a soluble plasma protein, to the insoluble protein fibrin and simultaneously converts factor XIII to factor XIIIa. This conversion of factors stabilizes fibrin and results in cross-linking of fibrin monomers, resulting in the generation of a stable clot.

[0006] During surgery, it is important to maintain a delicate balance between bleeding and clotting so that blood continues to flow to the tissues at the surgical site without excessive loss in order to optimize surgical success and patient outcomes. Persistent bleeding from diffuse capillaries or small veins during surgery can obscure the surgical field, prolong surgical times, increase the risk of physiological complications, and expose the patient to the risks associated with blood transfusions.

[0007] Surgeons have many options for controlling bleeding, including mechanical and thermal techniques and devices, as well as drug therapies and topical agents.

[0008] One of the earliest local hemostatic agents was cotton in the form of gauze sponges. Such materials concentrate blood and clotting products by physical adsorption, but are not absorbed by the body, and removal can dislodge the clot, leading to further bleeding. Since then, absorbent local hemostatic agents have been developed, providing a useful adjunct therapy when traditional hemostatic methods are ineffective or impractical. Local hemostatic agents can be applied directly to the bleeding site and can prevent persistent, unstoppable bleeding. Hemostasis using local agents can also avoid the adverse effects of systemic hemostatic agents, such as "undesirable" blood clotting. Furthermore, in surgical procedures where the amount of blood loss is unpredictable, local hemostatic agents can be used in smaller amounts when blood loss is low and in larger amounts during severe bleeding.

[0009] Currently, there are many topical hemostatic agents for use in surgery. These topical hemostatic agents can be divided into two categories: those that exert their mechanism of action on the coagulation cascade in a biologically active manner, and those that act passively by contact activation and promotion of platelet aggregation. Passive topical hemostatic agents include collagen, cellulose, and gelatin, and active agents include thrombin and products in which thrombin is combined with passive agents to give an active overall product.

[0010] US Patent Application Publication No. 2003 / 0064109 describes a dry hemostatic powder prepared by a method including providing an aqueous solution containing gelatin combined with at least one rehydration aid, drying the solution to produce a solid, grinding the solid to produce a powder, cross-linking the powder, removing at least 50% (w / w) of the rehydration aid, and drying the cross-linked gelatin to produce a powder. The rehydration aid may include at least one material selected from the group consisting of polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and dextran.

[0011] US Patent Application Publication No. 2012 / 0021058 describes a process for making a hemostatic composition, the process comprising a) providing a dry granular preparation of a biocompatible polymer, and b) coating the granules in the dry granular preparation with a preparation of a coagulation inducer, such as a thrombin solution. The biocompatible polymer may be selected from gelatin, soluble collagen, albumin, hemoglobin, fibrinogen, fibrin, casein, fibronectin, elastin, keratin, laminin, and derivatives or combinations thereof.

[0012] US Patent Application Publication No. 2013 / 0316974 describes a hemostatic material comprising a compacted ORC powder comprising particles having an average aspect ratio of about 1 to about 18. The hemostatic material may further comprise an additive selected from polysaccharides, calcium salts, anti-infective agents, hemostatic promoters, gelatin, and collagen.

[0013] US Patent Application Publication No. 2016 / 0271228 discloses a hemostatic composition comprising: a particulate form of a hemostatic biocompatible polymer selected from the group consisting of proteins, polysaccharides, biopolymers, non-biopolymers, and derivatives and combinations thereof, the particulate form being present as granular particles having a median diameter range of 50-700 μm; a hydrophilic crosslinker comprising electrophilic reactive groups, the electrophilic reactive groups remaining reactive until the composition is exposed to the patient's blood, the electrophilic reactive groups being configured to crosslink with proteins in the patient's blood to form a gel having sealing and hemostatic properties; a binder that does not react with the electrophilic reactive groups of one of the hydrophilic crosslinkers, A hemostatic composition is described, wherein the hemostatic composition is in the form of a paste.

[0014] WO 2012 / 057628 describes a kit for producing biocompatible crosslinked polymers, the kit comprising an electrophilically activated polyoxazoline (EL-POx), the EL-POX comprising m electrophilic groups, the nucleophilic crosslinker comprising n nucleophilic groups, the m electrophilic groups being capable of reacting with the n nucleophilic groups to form covalent bonds, where m>2, n>2 and m+n>5, and at least one of the m electrophilic groups is a pendant electrophilic group.

[0015] WO 2016 / 056901 describes an adhesive hemostatic product selected from a coated mesh, a coated foam, or a coated powder, the adhesive hemostatic product comprising: a porous solid substrate comprising an exterior surface having at least 5% by volume porosity and comprising a nucleophilic polymer containing reactive nucleophilic groups; an adhesive coating covering at least a portion of a solid substrate, the coating comprising an electrophilically activated polyoxazoline (EL-POX), the EL-POX comprising, on average, at least one reactive electrophilic group.

[0016] US Patent Application Publication No. 2016 / 0375202 discloses a device for expressing hemostatic powder, comprising: a) an elongated hollow reservoir having a manual air pump attached to the reservoir and an expression port at a distal end of the reservoir; b) a porous filter slidably disposed within the reservoir between the air pump and the squeeze port; c) a spring disposed within the reservoir between the air pump and the filter; The device describes a powder disposed in a reservoir between a filter and an expression port, and a pump in fluid communication with the expression port through the porous filter and the powder. Summary of the Invention [Means for solving the problem]

[0017] The present inventors have developed a bioabsorbable sealing powder that can be conveniently used to control bleeding and / or provide a protective seal during surgery.

[0018] The encapsulating powder of the present invention comprises: (a) at least 5% by weight of a water-soluble electrophilic polymer having at least three reactive electrophilic groups capable of reacting with amine groups under formation of covalent bonds; (b) 1-50 wt. % of a water soluble nucleophilic crosslinker having at least two reactive nucleophilic groups capable of reacting in the presence of water with a reactive electrophilic group of the electrophilic polymer under formation of a covalent bond between the electrophilic polymer and the nucleophilic crosslinker; (c) 1-60% by weight of water-absorbing particles, the water-absorbing particles comprising at least 50% by weight of the water-absorbing particles of a water-insoluble polymer containing reactive nucleophilic groups selected from amine groups, thiol groups, and combinations thereof; (d) 10 to 75% by weight of a water-soluble dispersant that is solid at 20° C., the water-soluble dispersant being selected from monosaccharides, disaccharides, oligosaccharides, sugar alcohols, and combinations thereof; the combination of components (a), (b), (c) and (d) constitutes at least 60% by weight of the encapsulating powder; The encapsulating powder has a tap density in the range of 0.3 to 0.9 g / ml; At least 90% by weight of the powder has a diameter less than 600 μm, and no more than 10% by weight of the powder has a diameter less than 10 μm; The bioabsorbable encapsulating powder comprises components (a), (b), (c) and (d) which may be contained in the same particle or in different particles.

[0019] The sealing powder of the present invention, when applied onto wet tissue, quickly forms a seal in the form of a hydrogel that adheres to the tissue. The sealing powder can be suitably used to provide an effective seal against air leaks in the lungs, for example. In addition, the sealing powder has excellent hemostatic capabilities due to the fact that it can absorb large amounts of blood under the formation of a strongly gelled clot that seals the bleeding site.

[0020] The sealing powder of the present invention can be easily distributed across tissue, and if desired, additional sealing powder can be applied to form an additional sealing layer that adheres to the underlying hydrogel layer.

[0021] Although the inventors do not wish to be bound by theory, it is believed that when a layer of hemostatic powder is applied to moist tissue, the water-soluble electrophilic polymer and the water-soluble nucleophilic polymer dissolve rapidly. The dissolved electrophilic polymer reacts with the reactive nucleophilic groups of the dissolved water-soluble nucleophilic polymer to form a hydrogel incorporating water-absorbing particles. These water-absorbing particles provide water absorption capacity due to their ability to swell. The dissolved electrophilic polymer also reacts with proteins in the tissue, thereby anchoring the hydrogel to the tissue. Additionally, the dissolved electrophilic polymer reacts with proteins in the blood, thereby producing a gelled clot.

[0022] The water-soluble dispersing agent in the sealing powder of the present invention ensures that the other components of the sealing powder are rapidly and uniformly dispersed when the sealing powder comes into contact with moisture. Additionally, the inclusion of a water-soluble dispersing agent allows for the preparation of a sealing powder composed of particles having a sufficiently high density to allow for precise application of the powder to tissue by airflow, such as that generated by a bellows.

[0023] Surprisingly, after the sealing powder has been applied onto the moist tissue, it can be conveniently compressed with a moist saline soaked gauze pad, as the gauze pad does not stick to the gelling / gelling sealing powder.

[0024] Another aspect of the present invention is a method for preparing the bioabsorbable encapsulating powder of the present invention, comprising the steps of: (a) providing a particle A comprising an electrophilic polymer and a water-soluble dispersant; (b) providing a particle B comprising a nucleophilic crosslinker, a water-absorbing particle, and a water-soluble dispersant; (c) combining particles A and particles B.

[0025] A further aspect of the invention is an apparatus for applying powder, comprising: a reservoir containing the bioabsorbable sealing powder of the present invention; an elongated hollow tubular structure having a proximal end and a distal end, the distal end having a powder outlet and the proximal end connected to a reservoir; a manual air pump, preferably a valve or bellows, arranged to generate an air flow that carries powder from a reservoir through an elongated hollow tubular structure and through a powder outlet.

[0026] Another aspect of the present invention is a biocompatible, flexible hemostatic sheet comprising: a cohesive fibrous carrier structure comprising three-dimensional interconnected interstitial spaces; The bioabsorbable sealing powder of the present invention, The present invention relates to a hemostatic sheet in which a sealing powder is distributed within the interstitial spaces and / or fixed onto a fibrous carrier structure.

[0027] The present invention also provides a kit of parts for preparing a bioabsorbable sealant suspension, comprising: a first container or compartment containing a biocompatible liquid; a second container or compartment containing the bioabsorbable sealing powder of the present invention.

[0028] Yet another aspect of the present invention is a bioabsorbable sealing suspension comprising: a biocompatible continuous liquid non-aqueous phase; a dispersed phase comprising the bioabsorbable encapsulating powder of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Thus, a first aspect of the present invention is a bioabsorbable sealing powder comprising: (a) at least 5% by weight of a water-soluble electrophilic polymer having at least three reactive electrophilic groups capable of reacting with amine groups under formation of covalent bonds; (b) 1-50 wt. % of a water soluble nucleophilic crosslinker having at least two reactive nucleophilic groups capable of reacting in the presence of water with a reactive electrophilic group of the electrophilic polymer under formation of a covalent bond between the electrophilic polymer and the nucleophilic crosslinker; (c) 1-60% by weight of water-absorbing particles, the water-absorbing particles comprising at least 50% by weight of the water-absorbing particles of a water-insoluble polymer containing reactive nucleophilic groups selected from amine groups, thiol groups, and combinations thereof; (d) 10 to 75% by weight of a water-soluble dispersant that is solid at 20° C., the water-soluble dispersant being selected from monosaccharides, disaccharides, oligosaccharides, sugar alcohols, and combinations thereof; the combination of components (a), (b), (c) and (d) constitutes at least 60% by weight of the encapsulating powder; The encapsulating powder has a tap density in the range of 0.3 to 0.9 g / ml; At least 90% by weight of the powder has a diameter less than 600 μm, and no more than 10% by weight of the powder has a diameter less than 10 μm; The bioabsorbable encapsulating powder comprises components (a), (b), (c) and (d) which may be contained in the same particle or in different particles.

[0030] As used herein, the term "bioabsorbable sealing powder" means that all components of the sealing powder are absorbed by the body. Some of the components of the sealing powder, particularly the polymeric components, are gradually degraded in the body before being absorbed.

[0031] As used herein, the term "water-soluble electrophilic polymer" refers to an electrophilic polymer that has a solubility of at least 50 g / L in demineralized water at 20° C. and pH 7. To determine the water solubility of a nucleophilic polymer at different pHs, the pH of the demineralized water is adjusted using hydrochloric acid.

[0032] As used herein, the term "polyoxazoline" refers to poly(N-acylalkyleneimine) or poly(aroylalkyleneimine), further referred to as POx. An example of POx is poly(2-ethyl-2-oxazoline). The term "polyoxazoline" also encompasses POx copolymers.

[0033] As used herein, the term "water-soluble nucleophilic crosslinker" refers to a nucleophilic crosslinker that has a solubility of at least 50 g / L in demineralized water at 20° C. and pH 7. To determine the water solubility of a nucleophilic crosslinker at different pHs, the pH of the demineralized water is adjusted using hydrochloric acid.

[0034] As used herein, the term "protein" also includes cross-linked and hydrolyzed proteins, unless otherwise specified. Similarly, whenever a particular protein species, such as gelatin or collagen, is mentioned, the hydrolyzed and cross-linked forms of that protein species are also included, unless otherwise specified.

[0035] The term "collagen" as used herein refers to the major structural protein in the extracellular space of various connective tissues in animals. Collagen forms a characteristic triple helix of three polypeptide chains. Depending on the degree of mineralization, collagen tissues can be either rigid (bone) or flexible (tendon), or have a gradient from rigid to flexible (cartilage). Unless otherwise specified, the term "collagen" also encompasses modified collagens other than gelatin (e.g., cross-linked collagens).

[0036] As used herein, the term "gelatin" refers to a mixture of peptides and proteins produced by partial hydrolysis of collagen extracted from the skin, bones, and connective tissues of animals such as livestock, chickens, pigs, and fish. During hydrolysis, the natural molecular bonds between the individual collagen chains are broken down into forms that more easily rearrange. As used herein, the term "gelatin" also encompasses modified gelatins, such as cross-linked gelatin and reduced cross-linked gelatin.

[0037] As used herein, the term "reduced cross-linked gelatin" refers to partially hydrolyzed cross-linked gelatin. Partial hydrolysis of peptide bonds in cross-linked gelatin can be achieved, for example, by alkaline treatment. Hydrolysis of cross-linked gelatin results in an increase in the density of free carboxyl and free amine groups.

[0038] As used herein, unless otherwise specified, the term "gel foam" refers to a cross-linked gelatin material having a sponge-like structure.

[0039] The term "water-insoluble polymer containing reactive nucleophilic groups" refers to a polymer containing reactive nucleophilic groups that has a solubility of less than 5 g / L in demineralized water at 20° C. and pH 7. To determine the water solubility of a water-soluble polymer at different pHs, the pH of the demineralized water is adjusted using hydrochloric acid.

[0040] As used herein, the term "hemostatic sheet" refers to a sheet capable of stopping bleeding from damaged tissue, unless otherwise specified. The hemostatic sheet of the present invention can achieve hemostasis by turning blood into a gel and / or by forming a seal that closes the wound site.

[0041] As used herein in relation to a fibrous carrier structure, the term "water-resistant" means that at neutral pH conditions (pH 7) and a temperature of 37°C, the structure is not water-soluble and does not disintegrate in water to form a colloidal dispersion.

[0042] As used herein, the term "interstitial space" refers to void ("empty") space within a fibrous carrier structure. The interstitial space within the fibrous carrier structure allows for the introduction of hemostatic powder into the structure. Also, blood and other bodily fluids can enter the interstitial space, thereby allowing the hemostatic powder to exert its hemostatic effect and / or provide tissue adhesive properties to the hemostatic sheet.

[0043] As used herein, the term "tapped density" refers to the density obtained by carefully filling a graduated cylinder (250 mL, 37 mm internal diameter) with 250 mL of powder and then mechanically tapping the cylinder until no further volume loss is observed. Tapped density is calculated as the mass divided by the final volume of the powder.

[0044] As used herein, the term "particle" includes both particles consisting of single uniform particles and agglomerates of sub-particles, unless otherwise specified. Agglomerates can be prepared by granulation techniques known in the art, such as wet granulation.

[0045] As used herein, the term "liquid" means a liquid at a temperature of 20° C. and a pressure of 1 atmosphere, unless otherwise specified.

[0046] The diameter distribution of the sealing powder and the particle components of the sealing powder can be suitably determined by laser diffraction using a Malvern Mastersizer 2000 in combination with a stainless steel sample dispersion unit. The sample dispersion unit is filled with approximately 120 ml of cyclohexane / diethyl ether (1:1 v / v), which is allowed to stabilize for 5-10 minutes at a stirring speed of 1800 rpm, after which a background measurement (blank measurement) is performed. The sample tube is shaken and rotated horizontally 20 times. Approximately 50 mg is then dispersed in the sample dispersion unit containing cyclohexane. After the sample is introduced into the dispersion unit, the sample is stirred at 1800 rpm for 1.5 minutes to ensure that all particles are properly dispersed before measurements are taken. No ultrasonic treatment is performed on the dispersed particles. The average particle size is determined by D[4,3], the volume weighted mean diameter (ΣniDi 4 ) / (ΣniDi 3 )

[0047] In addition to components (a), (b), (c) and (d), the sealing powder of the present invention may suitably contain one or more other ingredients, such as a surfactant, a buffer and / or a polysaccharide. Preferably, the combination of components (a), (b), (c) and (d) constitutes at least 80% by weight of the sealing powder, most preferably at least 90% by weight.

[0048] The encapsulating powder preferably has a tap density in the range of 0.25 to 0.8 g / ml, more preferably 0.3 to 0.6 g / ml.

[0049] According to another preferred embodiment, at least 90% by weight of the sealing powder has a diameter less than 500 μm and not more than 10% by weight of the sealing powder has a diameter less than 20 μm. More preferably, at least 90% by weight of the sealing powder has a diameter less than 400 μm and not more than 10% by weight of the sealing powder has a diameter less than 40 μm.

[0050] Preferably, at least 50% by weight of the encapsulating powder has a diameter in the range of 65-300 μm, more preferably in the range of 80-280, and most preferably in the range of 100-200 μm.

[0051] The encapsulating powder preferably has a volume weighted mean diameter (D[4,3]) in the range of 65 to 300 μm, more preferably 80 to 250 μm, and most preferably 125 to 180 μm.

[0052] The water-soluble electrophilic polymer contained in the sealing powder of the present invention is preferably selected from electrophilic polyoxazolines, electrophilic polyethylene glycols, and combinations thereof.

[0053] Preferably, the encapsulating powder contains 10 to 50% by weight, more preferably 20 to 30% by weight, of the water-soluble electrophilic polymer.

[0054] The water-soluble electrophilic polymer preferably has a solubility in demineralized water at 20° C. in the pH range of 3-7 of at least 100 g / L, more preferably at least 200 g / L.

[0055] The water-soluble electrophilic polymer preferably has a solubility in acetone at 20° C. of less than 10 mg / L, more preferably less than 5 mg / L, and most preferably less than 1 mg / L.

[0056] The water-soluble electrophilic polymer preferably has a molecular weight of at least 2 kDa, more preferably the electrophilic polymer has a molecular weight of 5 to 200 kDa, most preferably 10 to 100 kDa.

[0057] The water-soluble electrophilic polymer and the water-soluble nucleophilic crosslinker are preferably combined in the encapsulating powder of the present invention with minimal crosslinking reaction between the electrophilic polymers and minimal degradation of the electrophilic polymer.Thus, in a highly preferred embodiment of the present invention, the water-soluble electrophilic polymer in the encapsulating powder has a polydispersity index (PDI) of less than 2.0, more preferably less than 1.8, and most preferably less than 1.5.

[0058] The water-soluble electrophilic polymer preferably contains at least 4 reactive electrophilic groups, more preferably at least 8 reactive electrophilic groups, even more preferably at least 16 reactive electrophilic groups, and most preferably at least 32 reactive electrophilic groups.

[0059] The water-soluble electrophilic polymer generally has an average of at least 10, more preferably at least 20, reactive electrophilic groups.

[0060] According to a particularly preferred embodiment, the electrophilic polymer is an electrophilic polyoxazoline.

[0061] The electrophilic polyoxazoline is preferably derived from a polyoxazoline having a repeating unit represented by the following formula (I): (CHR 1 ) m NCOR 2 In the formula, R 2 , and R 1 Each of 1~22 and m is selected from alkyl, optionally substituted cycloalkyl, optionally substituted aralkyl, and optionally substituted aryl; and m is 2 or 3.

[0062] Preferably, R in formula (I) 1 and R 2 H and C 1~8 alkyl, and even more preferably H and C 1~4 R is selected from alkyl. 1 is most preferably H. The integer m in formula (I) is preferably equal to 2.

[0063] According to a preferred embodiment, the polyoxazoline is a polymer, even more preferably a homopolymer, of 2-alkyl-2-oxazoline, said 2-alkyl-2-oxazoline being selected from 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-propyl-2-oxazoline, 2-butyl-2-oxazoline and combinations thereof. Preferably, the polyoxazoline is a homopolymer of 2-propyl-2-oxazoline or 2-ethyl-oxazoline. Most preferably, the polyoxazoline is a homopolymer of 2-ethyl-oxazoline.

[0064] According to a particularly preferred embodiment, the electrophilic polyoxazoline comprises at least 20 oxazoline units, more preferably at least 30 oxazoline units, and most preferably at least 80 oxazoline units.

[0065] The electrophilic polyoxazoline preferably contains an average of at least 0.05 reactive electrophilic groups per oxazoline residue. Even more preferably, the electrophilic polyoxazoline contains an average of at least 0.1 reactive electrophilic groups per oxazoline residue. Most preferably, the electrophilic polyoxazoline contains an average of 0.12 to 0.5 reactive electrophilic groups per oxazoline residue.

[0066] The polyoxazoline may have reactive electrophilic groups at its side chains (pendant reactive electrophilic groups), at its termini, or both. The electrophilic polyoxazolines used according to the invention advantageously contain one or more pendant reactive electrophilic groups.

[0067] Typically, the electrophilic polyoxazoline contains from 0.03 to 0.5 pendant reactive electrophilic groups per monomer, more preferably from 0.04 to 0.35 pendant reactive electrophilic groups per monomer, and even more preferably from 0.05 to 0.25 pendant reactive electrophilic groups per monomer.

[0068] According to a preferred embodiment, the reactive electrophilic groups of the electrophilic polyoxazoline are selected from carboxylate esters, sulfonate esters, phosphonate esters, pentafluorophenyl esters, p-nitrophenyl esters, p-nitrothiophenyl esters, acid halide groups, anhydrides, ketones, aldehydes, isocyanates, thioisocyanates, isocyano, epoxides, activated hydroxyl groups, olefins, glycidyl ethers, carboxyls, succinimidyl esters, sulfosuccinimidyl esters, maleimides (maleimidyl), ethenesulfonyl, imidoesters, acetoacetates, haloacetals, orthopyridyl disulfides, dihydroxy-phenyl derivatives, vinyls, acrylates, acrylamides, iodoacetamides, and combinations thereof. More preferably, the reactive electrophilic group is selected from carboxylate esters, sulfonate esters, phosphonate esters, pentafluorophenyl esters, p-nitrophenyl esters, p-nitrothiophenyl esters, acid halide groups, anhydrides, ketones, aldehydes, isocyanates, thioisocyanates, isocyano, epoxides, activated hydroxyl groups, glycidyl ethers, carboxyls, succinimidyl esters, sulfosuccinimidyl esters, imido esters, dihydroxy-phenyl derivatives, and combinations thereof. Even more preferably, the reactive electrophilic group is selected from haloacetals, orthopyridyl disulfides, maleimides, vinyl sulfones, dihydroxyphenyl derivatives, vinyls, acrylates, acrylamides, iodoacetamides, succinimidyl esters, and combinations thereof. Most preferably, the reactive electrophilic group is selected from maleimides, vinyls, acrylates, acrylamides, succinimidyl esters, sulfosuccinimidyl esters, and combinations thereof.

[0069] Examples of succinimidyl esters that may be used include succinimidyl glutarate, succinimidyl propionate, succinimidyl succinamide, succinimidyl carbonate, disuccinimidyl suberate, bis(sulfosuccinimidyl)suberate, dithiobis(succinimidyl propionate), bis(2-succinimidooxycarbonyloxy)ethyl sulfone, 3,3'-dithiobis(sulfosuccinimidyl-propionate), succinimidyl carbamate, sulfosuccinimidyl di(4-iodoacetyl)aminobenzoate, bis(sulfosuccinimidyl)suberate, sulfosuccinimidyl-4-(N-maleimidomethyl)-cyclohexane-1-carboxylate, dithiobis-sulfosuccinimidyl propionate, disulfo-succinimidyl tartrate; bis[2-(sulfo-succinimidyloxycarbonyloxyethyl sulfone)], ethylene glycol bis(sulfosuccinimicryl succinate), dithiobis-(succinimidyl propionate).

[0070] Examples of dihydroxyphenyl derivatives that can be used include dihydroxyphenylalanine, 3,4-dihydroxyphenylalanine (DOPA), dopamine, 3,4-dihydroxyhydroccinamic acid (DOHA), norepinephrine, epinephrine and catechol.

[0071] The water-soluble nucleophilic crosslinking agent used in the sealing powder of the present invention is preferably selected from nucleophilic polyoxazoline, nucleophilic polyethylene glycol, polyethyleneimine, protein, and combinations thereof, and combinations thereof.More preferably, the nucleophilic crosslinking agent is selected from nucleophilic polyoxazoline, nucleophilic polyethylene glycol, and combinations thereof.Most preferably, the nucleophilic crosslinking agent is nucleophilic polyoxazoline.

[0072] The water-soluble nucleophilic crosslinker preferably contains at least 3 reactive nucleophilic groups, more preferably at least 4 reactive nucleophilic groups, even more preferably at least 8 reactive nucleophilic groups, and most preferably at least 10. Most preferably, these reactive nucleophilic groups are amine groups, and most preferably primary amine groups.

[0073] According to one embodiment of the present invention, the water-soluble nucleophilic crosslinker is a nucleophilic polyethylene glycol (PEG). Preferably, the nucleophilic PEG contains at least 3, more preferably at least 5, and most preferably 8 reactive nucleophilic groups.

[0074] According to a particularly preferred embodiment, the nucleophilic crosslinker is a nucleophilic polyoxazoline. Preferably, the nucleophilic polyoxazoline contains at least 3, more preferably at least 5, and most preferably 8 to 20 reactive nucleophilic groups.

[0075] Preferably, the nucleophilic polyoxazoline contains an average of at least 0.1 reactive nucleophilic groups per oxazoline residue, and most preferably, the nucleophilic polyoxazoline contains an average of 0.12 to 0.5 reactive nucleophilic groups per oxazoline residue.

[0076] Preferably, the encapsulating powder contains 1.5-35% by weight, more preferably 2-20% by weight, and most preferably 3-10% by weight of the water-soluble nucleophilic crosslinker.

[0077] The water-soluble nucleophilic crosslinking agent preferably has a solubility in demineralized water at pH 7, 20° C. of at least 100 g / L, more preferably at least 200 g / L.

[0078] The water-soluble nucleophilic crosslinking agent preferably has a solubility in acetone at 20° C. of less than 10 mg / L, more preferably less than 5 mg / L, and most preferably less than 1 mg / L.

[0079] According to a particularly preferred embodiment, the water-soluble nucleophilic crosslinker dissolves relatively slowly in water. It is believed that if the water-soluble electrophilic polymer reacts with the water-soluble nucleophilic crosslinker at a relatively slow rate, the electrophilic polymer can also react with the proteins in the blood and tissue at the bleeding site. By using a water-soluble nucleophilic crosslinker that dissolves relatively slowly, the dissolved electrophilic polymer has the potential to (gradually) react with the proteins in the blood and tissue as well as the water-soluble nucleophilic crosslinker, thereby forming a strong and homogeneous sealing gel.

[0080] Water-soluble nucleophilic crosslinkers having high molecular weights tend to dissolve relatively slowly in water. Thus, in highly preferred embodiments, the water-soluble nucleophilic crosslinker has a molecular weight of at least 3 kDa, more preferably at least 10 kDa, and most preferably between 20 and 3,000 kDa.

[0081] In the present invention, a water-soluble nucleophilic crosslinker that is soluble at acidic pH can be suitably used when the water-soluble electrophilic polymer releases an acidic substance when reacting with a nucleophilic group, for example, when the electrophilic polymer contains an N-hydroxysuccinimide group.

[0082] According to a preferred embodiment, the water-soluble nucleophilic crosslinker has two or more amine groups and the reactive electrophilic groups of the water-soluble electrophilic polymer are selected from carboxylate esters, sulfonate esters, phosphonate esters, pentafluorophenyl esters, p-nitrophenyl esters, p-nitrothiophenyl esters, acid halide groups, anhydrides, ketones, aldehydes, isocyanates, thioisocyanates, isocyano, epoxides, activated hydroxyl groups, glycidyl ethers, carboxyls, succinimidyl esters, sulfosuccinimidyl esters, imido esters, dihydroxy-phenyl derivatives, and combinations thereof.

[0083] According to another preferred embodiment, the water-soluble nucleophilic crosslinker has two or more thiol groups, and the reactive electrophilic groups of the water-soluble electrophilic polymer are selected from haloacetals, orthopyridyl disulfides, maleimides, vinyl sulfones, dihydroxyphenyl derivatives, vinyls, acrylates, acrylamides, iodoacetamides, succinimidyl esters, sulfosuccinimidyl esters, and combinations thereof. More preferably, the reactive electrophilic groups are selected from succinimidyl esters, sulfosuccinimidyl esters, haloacetals, maleimides, or dihydroxyphenyl derivatives, and combinations thereof. Most preferably, the reactive electrophilic groups are selected from maleimides or dihydroxyphenyl derivatives, and combinations thereof.

[0084] The combination of the water-soluble electrophilic polymer and the water-soluble nucleophilic crosslinker preferably constitutes at least 20% by weight of the encapsulating powder, more preferably 20-60% by weight, and most preferably 25-35% by weight.

[0085] The ratio between the total number of reactive electrophilic groups provided by the water-soluble electrophilic polymer and the total number of reactive nucleophilic groups provided by the water-soluble nucleophilic crosslinker is preferably in the range of 1:0.05 to 1:0.4, more preferably in the range of 1:0.1 to 1:0.3, and most preferably in the range of 1:0.15 to 1:0.25.

[0086] The bioabsorbable encapsulating powder of the present invention contains preferably 10 to 60% by weight, more preferably 12 to 40% by weight, and most preferably 15 to 30% by weight of water-absorbing particles containing a water-insoluble polymer containing a reactive nucleophilic group.

[0087] According to a particularly preferred embodiment, the water-absorbing particles are water-resistant, meaning that these particles are not water-soluble and do not disintegrate to form a colloidal dispersion in water at neutral pH conditions (pH 7) and a temperature of 37° C. Gel foam particles can be suitably used as water-absorbing particles according to the present invention.

[0088] The water-absorbing particles preferably contain at least 50%, more preferably at least 70%, by weight of the water-absorbing particle, of a water-insoluble polymer containing reactive nucleophilic groups selected from amine groups, thiol groups, and combinations thereof.

[0089] According to a particularly preferred embodiment, the water-absorbing particle contains at least 10% by weight of the water-absorbing particle, more preferably at least 15% by weight of the water-absorbing particle, of a water-insoluble polymer containing reactive amine groups.

[0090] Water-insoluble polymers containing reactive nucleophilic groups preferably have a water solubility in demineralized water at pH 7, 20° C. of less than 3 g / L, more preferably less than 2 g / L.

[0091] Water-insoluble polymers containing reactive nucleophilic groups preferably have a solubility in acetone at 20° C. of less than 10 mg / L, more preferably less than 5 mg / L, and most preferably less than 1 mg / L.

[0092] The water-insoluble polymer containing reactive nucleophilic groups contained in the water-absorbing particles is preferably selected from proteins, chitosan and combinations thereof. Most preferably, the water-insoluble polymer containing reactive nucleophilic groups is a protein.

[0093] Chitosan is a biodegradable, non-toxic, complex carbohydrate derivative of the naturally occurring substance chitin (poly-N-acetyl-D-glucosamine). Chitosan is the deacetylated form of chitin. Chitosan applied according to the invention preferably has a degree of deacetylation of more than 50%. Chitosan used according to the invention preferably has a molecular weight of at least 5 kDa, more preferably between 10 and 10,000 kDa.

[0094] Examples of proteins that can be used include gelatin, cross-linked gelatin, collagen, and combinations thereof. More preferably, the water-insoluble polymer containing reactive nucleophilic groups is cross-linked gelatin.

[0095] The crosslinked gelatin has a molecular weight preferably in the range of 30 to 3,000 kDa, more preferably in the range of 400 to 2,000 kDa, and most preferably in the range of 500 to 1,500 kDa.

[0096] The average primary amine content of the crosslinked gelatin is preferably 5×10 per μg of reduced crosslinked gelatin. -4 ~2×10 -2 μmol, more preferably 1.0×10 -3 ~1.0×10 -2 It is a primary amine in the μmol range.

[0097] The water-absorbing particles used in the encapsulating powder of the present invention preferably have a volume weighted mean diameter (D[4,3]) of at least 10 μm, more preferably in the range of 20 to 250 μm, and most preferably in the range of 25 to 180 μm.

[0098] The water-absorbing particles have a water-absorption capacity of at least 0.2 grams of water per gram of water-absorbing particle, more preferably 0.5 to 3 grams of water per gram of water-absorbing particle, and most preferably 0.8 to 2 grams of water per gram of water-absorbing particle. The water-absorption capacity can be suitably determined by gravimetry.

[0099] The water-soluble dispersant contained in the encapsulated powder of the present invention is preferably selected from sucrose, trehalose, lactose, maltitol, mannitol, sorbitol, xylitol, cyclodextrin, maltodextrin, dextran, and combinations thereof, and more preferably, the water-soluble dispersant is selected from sucrose, trehalose, mannitol, and combinations thereof.

[0100] The water-soluble dispersant preferably has a glass transition temperature above 30°C, more preferably a glass transition temperature of 50 to 200°C, and most preferably a glass transition temperature of 75 to 95°C.

[0101] Preferably, the encapsulating powder contains 25-70% by weight, more preferably 30-65% by weight, and most preferably 40-60% by weight of the water-soluble dispersant.

[0102] In a preferred embodiment, the sealing powder contains at least 30% by weight, more preferably at least 35% by weight, and most preferably at least 40% by weight of particles comprising both components (a) and (d).

[0103] According to another preferred embodiment, the sealing powder contains at least 20% by weight, more preferably at least 30% by weight, and most preferably at least 40% by weight of particles comprising both components (b) and (d).

[0104] According to a particularly preferred embodiment, the sealing powder contains at least 20% by weight, more preferably at least 30% by weight, and most preferably at least 40% by weight of particles comprising both components (b), (c) and (d).

[0105] The sealing powder of the present invention may be composed of particles having the same composition or may be a mixture of different particles. Examples of mixtures of different particles include:

[0106] (a) (i) a mixture of particles containing only components (a) and (d) and (ii) particles containing only components (b), (c) and (d); (b) a mixture of i) particles containing only components (a) and (d), (ii) particles containing only components (b) and (d), and (iii) particles containing only components (c) and (d).

[0107] Here, the term "only" is used to indicate that in addition to the mentioned component, the particles do not contain any of the other components (a)-(d) of the encapsulating powder.

[0108] When the encapsulating powder consists of a mixture of different particles, the powder preferably comprises 30-70% by weight of particles containing only components (a) and (d) and 30-70% by weight of particles containing only components (b), (c) and (d).More preferably, the encapsulating powder comprises 40-60% by weight of particles containing only components (a) and (d) and 40-60% by weight of particles containing only components (b), (c) and (d).

[0109] Preferably, the particles containing only components (a) and (d) and the particles containing only components (b), (c) and (d) together constitute at least 60% by weight of the encapsulating powder, more preferably at least 80% by weight, and most preferably at least 90% by weight.

[0110] In a particularly preferred embodiment, the sealing powder of the present invention contains at least 60% by weight, more preferably at least 80% by weight, and most preferably at least 90% by weight of particles containing each of components (a), (b), (c) and (d). Such particles can be prepared, for example, by granulation of a mixture of different particles as described above.

[0111] According to another particularly preferred embodiment, the encapsulating powder contains at least 50% by weight, more preferably at least 70% by weight, most preferably at least 80% by weight of particles containing each of components (a), (b), (c) and (d) in the form of an agglomerate of subparticles A containing only components (a) and (d) and subparticles B containing only components (b), (c) and (d). Preferably, the agglomerate of subparticles A and B contains 20-80% by weight of subparticles A and 20-80% by weight of subparticles B. More preferably, the agglomerate of subparticles A and B contains 40-60% by weight of subparticles A and 40-60% by weight of subparticles B.

[0112] Preferably, the particles of the encapsulating powder contain 0.05 to 5 wt %, more preferably 0.1 to 2 wt %, of a surfactant having a melting point of 30° C. or higher.

[0113] In preferred embodiments, the surfactant is selected from block copolymer surfactants, polyoxyethylene stearate, sodium dodecyl sulfate, and combinations thereof, more preferably a poloxamer, most preferably poloxamer 188 or poloxamer 407.

[0114] According to another preferred embodiment, the surfactant is contained in the particles further comprising components (b) and (d), more preferably in the particles further comprising components (b), (c) and (d), most preferably in the particles further comprising components (a), (b), (c) and (d).

[0115] Another aspect of the present invention relates to a method of treating a wound or reducing bleeding at a bleeding site, comprising topically administering to the wound or bleeding site a sealing powder according to the present invention.

[0116] Preferably, in the treatment method of the present invention, the powder has a concentration of 5 to 250 mg / cm 2 More preferably, the amount is 20 to 200 mg / cm 2 and most preferably in an amount of 50 to 125 mg / cm 2 is administered topically in an amount of

[0117] The method of the present invention is particularly suitable for the topical treatment of wounds selected from a) minor abrasions, cuts, abrasions, scratches, burns, sunburn, ulcers, internal venous bleeding, external venous bleeding, and b) wounds selected from gastrointestinal surgery, surgery of solid organs; surgical interventions in the ear, nose and throat area (ENT), cardiovascular surgery, cosmetic surgery, spinal surgery, neurological surgery; air leaks in lymphatic, bile duct and cerebrospinal (CSF) fistulas, chest and lung surgery, respiratory surgery, orthopedic surgery; gynecological surgery; vascular and emergency surgery, liver resection, and soft tissue injuries or surgery.

[0118] A further aspect of the present invention is a method for preparing the bioabsorbable encapsulating powder of the present invention, comprising the steps of: (a) providing a particle A comprising a water-soluble electrophilic polymer and a water-soluble dispersant; (b) providing particles B comprising a water-soluble nucleophilic crosslinker, a water-absorbing particle, and a water-soluble dispersant; (c) combining particles A and particles B.

[0119] In the preparation method of the present invention, premature crosslinking reactions between the water-soluble electrophilic polymer, on the one hand, and the water-soluble nucleophilic crosslinker and the water-insoluble polymer containing reactive nucleophilic groups, on the other hand, are effectively avoided.

[0120] The particles A preferably contain 20 to 90% by weight of the water-soluble electrophilic polymer and 10 to 80% by weight of the water-soluble dispersant, more preferably 30 to 70% by weight of the water-soluble electrophilic polymer and 30 to 70% by weight of the water-soluble dispersant, and most preferably 40 to 60% by weight of the water-soluble electrophilic polymer and 40 to 60% by weight of the water-soluble dispersant.

[0121] The water-soluble electrophilic polymer and the water-soluble dispersant together preferably constitute at least 60% by weight of particles A, more preferably at least 80% by weight, and most preferably at least 90% by weight.

[0122] Particles A are preferably prepared by agglomerating particles of a water-soluble electrophilic polymer and particles of a water-soluble dispersant. Agglomeration is preferably achieved by wet granulation.

[0123] Particle B preferably contains 5-20% by weight of a water-soluble nucleophilic crosslinking agent, 25-60% by weight of water-absorbing particles, and 30-70% by weight of a water-soluble dispersing agent. More preferably, particle B contains 6-18% by weight of a water-soluble nucleophilic crosslinking agent, 30-50% by weight of water-absorbing particles, and 35-65% by weight of a water-soluble dispersing agent. Most preferably, particle B contains 8-15% by weight of a water-soluble nucleophilic crosslinking agent, 35-45% by weight of water-absorbing particles, and 40-60% by weight of a water-soluble dispersing agent.

[0124] The water-soluble nucleophilic crosslinker, the water-absorbing particles, the water-absorbing particles and the water-soluble dispersant together preferably constitute at least 60% by weight of Particle B, more preferably at least 80% by weight, and most preferably at least 90% by weight.

[0125] Particles B are preferably prepared by agglomeration of particles of a water-soluble nucleophilic polymer, particles of a water-insoluble absorbing particle and particles of a water-soluble dispersant. Agglomeration is preferably achieved by wet granulation.

[0126] Combining particles A and B is preferably accomplished by simple mixing or by granulation (to form agglomerates).

[0127] When particles A and B are combined by simple mixing, particles A preferably have a volume weighted average diameter (D[4,3]) in the range of 25 to 300 μm, more preferably in the range of 80 to 250 μm, and most preferably in the range of 125 to 180 μm. In the case of simple mixing, particles B preferably have a volume weighted average diameter (D[4,3]) in the range of 25 to 300 μm, more preferably in the range of 80 to 250 μm, and most preferably in the range of 125 to 180 μm.

[0128] Preferably, particles A and particles B are combined into an agglomerate. According to a particularly preferred embodiment, particles A and particles B are combined into an agglomerate by wet granulation. More preferably, particles A and particles B are combined as an agglomerate using a non-aqueous granulation liquid containing at least 60% by weight of an organic solvent selected from acetone, isopropyl alcohol, ethanol, methanol, diethyl ether, heptane, hexane, pentane, cyclohexane, dichloromethane and mixtures thereof. More preferably, the non-aqueous granulation liquid contains at least 60% by weight, most preferably at least 85% by weight of an organic solvent selected from acetone, isopropyl alcohol, ethanol and mixtures thereof. Even more preferably, the non-aqueous granulation liquid contains at least 60% by weight, most preferably at least 85% by weight of acetone.

[0129] When particles A and B are combined by granulation, particles A preferably have a volume weighted average diameter (D[4,3]) in the range of 10 to 200 μm, more preferably in the range of 20 to 150 μm, and most preferably in the range of 25 to 120 μm. In the case of granulation, the volume weighted average diameter (D[4,3]) of particles B is preferably in the range of 10 to 200 μm, more preferably in the range of 20 to 150 μm, and most preferably in the range of 25 to 120 μm.

[0130] The non-aqueous granulating liquid preferably contains no more than 1% water by weight, more preferably no more than 0.1% water by weight.

[0131] The amount of non-aqueous granulation liquid used in the present method to combine particles A and B is preferably in the range of 0.5 to 5% by weight of the combined amount of particles A and B. More preferably, the amount of non-aqueous granulation liquid used is in the range of 1 to 4% by weight, and most preferably 1.5 to 3% by weight, of the combined amount of particles A and B.

[0132] Yet another aspect of the present invention is an apparatus for applying powder, comprising: a reservoir containing the bioabsorbable sealing powder according to the invention; an elongated hollow tubular structure having a proximal end and a distal end, the distal end having a powder outlet and the proximal end connected to a reservoir; a manual air pump attached to the reservoir and arranged to generate an air flow that carries powder from the reservoir through the elongated hollow tubular structure and through the powder outlet.

[0133] According to a preferred embodiment, the device comprises a porous filter disposed in the reservoir between the air pump and the powder outlet, the powder being disposed in the reservoir between the filter and the powder outlet, the pump being in fluid communication with the powder outlet through the porous filter and through the powder, the filter preferably being impermeable to the powder contained in the reservoir.

[0134] Preferably, the manual air pump comprises a bellows.

[0135] The sealing powder of the present invention can be advantageously applied to a hemostatic sheet to improve its adhesive and hemostatic properties. Accordingly, another aspect of the present invention is a biocompatible, flexible hemostatic sheet comprising: a cohesive fibrous carrier structure comprising three-dimensional interconnected interstitial spaces; the bioabsorbable encapsulating powder according to the present invention; The present invention relates to a hemostatic sheet in which a sealing powder is distributed within the interstitial spaces and / or fixed onto a fibrous carrier structure.

[0136] The sealing powder can be suitably fixed onto the fibrous carrier structure by a binder, preferably an adhesive comprising a meltable solid binder, examples of such binders include polyester, polypropylene, acrylic or polyethylene based powders.

[0137] According to a preferred embodiment, the sealing powder is distributed within the interstitial spaces of the fibrous carrier.

[0138] The adhesive fibrous carrier structure of the hemostatic sheet is preferably water resistant.

[0139] According to a particularly preferred embodiment, the hemostatic sheet of the present invention is bioabsorbable. Resorption of the carrier structure and sealing powder generally requires chemical degradation (e.g., hydrolysis) of the polymers contained therein. Complete absorption of the hemostatic sheet by the human body is generally achieved in 1 to 10 weeks, preferably 2 to 8 weeks.

[0140] The hemostatic sheet of the present invention generally has an uncompressed average thickness of 0.5 to 25 mm, more preferably in the range of 1 to 10 mm, and most preferably in the range of 1.5 to 5 mm.

[0141] The dimensions of the hemostatic sheet are preferably at least 2 cm on each of the upper and lower surfaces of the sheet. 2 , more preferably at least 10 cm 2 , most preferably 25-50 cm2 Generally, the sheets are rectangular and have a length of 25 to 200 mm and a width of 25 to 200 mm.

[0142] The hemostatic sheet is preferably 200 mg / cm 3 less than 150 mg / cm 3 less than 10-100 mg / cm 3 It has an uncompressed density of

[0143] The hemostatic sheets of the present invention are preferably essentially anhydrous. Generally, the hemostatic sheets will have a moisture content of 5% by weight or less, more preferably 2% by weight or less, and most preferably 1% by weight or less.

[0144] The water absorption capacity of the hemostatic sheet is preferably at least 50%, more preferably in the range of 100% to 800%, and most preferably in the range of 200% to 500%.

[0145] The hemostatic sheet of the present invention is preferably sterile.

[0146] The use of a fibrous carrier structure in the hemostatic sheet of the present invention provides the advantage that the sealing powder can be easily distributed evenly throughout the carrier structure, which is much more difficult to achieve with, for example, a foam carrier structure.

[0147] The fibres in the fibrous support structure preferably have an average diameter of 1 to 500 μm, more preferably 2 to 300 μm, most preferably 5 to 200 μm. The average fibre diameter can conveniently be determined using a microscope.

[0148] Typically, at least 50% by weight, more preferably at least 80% by weight, of the fibres in the fibrous support structure have a diameter of 1 to 300 μm and a length of at least 1 mm.

[0149] Preferably, at least 50% by weight of the fibers in the fibrous support structure have an aspect ratio (ratio of length to diameter) of at least 1000, more preferably at least 80% by weight.

[0150] The fibrous carrier structure used according to the invention is preferably a felt, woven or knitted structure. Most preferably, the fibrous carrier structure is a felt structure. Here, the term "felt structure" refers to a structure produced by matting fibers and pressing them together to form a cohesive material.

[0151] The fibrous carrier structure preferably comprises at least 50% by weight, more preferably at least 80% by weight, and most preferably at least 90% by weight, of fibers containing a fiber polymer selected from gelatin, collagen, cellulose, modified cellulose, carboxymethyl dextran, poly(lactic-co-glycolic acid) (PLGA), sodium hyaluronate / carboxymethyl cellulose, polyvinyl alcohol, chitosan, and combinations thereof.

[0152] According to a particularly preferred embodiment, the fibrous carrier structure comprises at least 50% by weight, more preferably at least 80% by weight, most preferably at least 90% by weight of fibers containing gelatin and / or modified cellulose. The gelatin used is preferably crosslinked gelatin. The modified cellulose used is preferably oxidized cellulose, most preferably oxidized regenerated cellulose.

[0153] In another preferred embodiment, the fibrous support structure comprises at least 50% by weight, more preferably at least 80% by weight, and most preferably at least 90% by weight of fibers containing at least 80% by weight of one or more fiber polymers as described above.

[0154] Preferred fibrous support structures have a flow rate of at least 0.1 L / min×cm 2, more preferably at least 0.5 L / min×cm 2 The air permeability is determined in accordance with EN ISO 9237:1995 (Textiles - Determination of the permeability of fabrics to air).

[0155] The fibers in the fibrous carrier structure can be produced by methods known in the art, such as electrospinning, electroblow spinning, and high-speed rotary spray spinning. The production of fibrous carrier structures by high-speed rotary spray spinning is described in U.S. Patent Application Publication No. 2015 / 0010612. It is also possible to use commercially available hemostatic fibrous sheets as the fibrous carrier structure.

[0156] The sealing powder is present in the hemostatic sheet of the present invention in an amount of preferably 5-90% by weight of the fibrous carrier structure, more preferably 10-80% by weight, even more preferably 20-75% by weight, and most preferably 50-70% by weight.

[0157] A further aspect of the present invention is a kit of parts for preparing a bioabsorbable sealant suspension comprising: a first container or compartment containing a biocompatible liquid; a second container or compartment containing the bioabsorbable sealing powder of the present invention.

[0158] A bioabsorbable suspension can be prepared using the above kit by mixing a biocompatible liquid with a sealing powder. The suspension thus obtained can be effectively applied to fill and seal, for example, pleural cavities or hemorrhages.

[0159] The biocompatible liquid preferably contains one or more biocompatible liquids selected from polyethylene glycol, propylene glycol, triethyl citrate, polyglycerol, DMSO, glycerol, diacetin, triacetin, N-methyl pyrrolidone (NMP), water and mixtures thereof. The polyethylene glycol used in the suspension preferably has a molecular weight of 550 g / mol or less, more preferably 450 g / mol or less.

[0160] The biocompatible liquid of the kit may suitably contain water. The presence of water in the biocompatible liquid allows cross-linking reactions to occur between the components of the sealing powder before the sealing suspension is applied to tissue. These initial cross-linking reactions increase the viscosity and adhesion of the suspension, facilitating application of the suspension to tissue. The water content of the biocompatible liquid is preferably in the range of 1-50% by weight, more preferably not exceeding 2-30% by weight, and most preferably not exceeding 3-10% by weight.

[0161] The biocompatible liquid may suitably contain a buffer and / or a viscosity adjusting agent, such as hyaluronic acid, alginate, carboxymethylcellulose, and combinations thereof.

[0162] Yet another aspect of the present invention is a bioabsorbable sealing suspension comprising: a biocompatible continuous liquid non-aqueous phase; a dispersed phase comprising the bioabsorbable sealing powder according to the present invention.

[0163] The non-aqueous phase of the sealing suspension preferably contains one or more biocompatible liquids selected from polyethylene glycol, propylene glycol, triethyl citrate, polyglycerol, DMSO, glycerol, diacetin, triacetin, N-methylpyrrolidone (NMP) and mixtures thereof. The polyethylene glycol used in the suspension preferably has a molecular weight of 550 g / mol or less, more preferably 450 g / mol or less.

[0164] The water content of the non-aqueous phase preferably does not exceed 3% by weight, more preferably does not exceed 1% by weight, and most preferably does not exceed 0.3% by weight.

[0165] In addition to the sealing powder, the non-aqueous phase may suitably contain other ingredients such as a buffer, and a viscosity modifier (eg, hyaluronic acid, alginate, and / or carboxymethylcellulose).

[0166] The encapsulating suspension preferably contains 5 to 75% by weight, more preferably 10 to 40% by weight, and most preferably 15 to 30% by weight of the encapsulating powder.

[0167] Particles of the sealing powder in the suspension may begin to settle or float over time, so the suspension may need to be shaken or stirred before use.

[0168] The invention is further illustrated by the following non-limiting examples. EXAMPLES

[0169] Generally, unless the residual moisture after drying (ie, the residual water in the dry powder, granules and / or sticky fibrous carrier structure) is explicitly stated, the amount is less than 2.0 w / w%.

[0170] Preparation of NHS-POx NHS-side chain activated poly[2-(ethyl / hydroxy-ethyl-amido-ethyl / NHS-ester-ethyl-ester-ethyl-amido-ethyl)-2-oxazoline] terpolymer containing 20% ​​NHS-ester groups (=EL-POx, 20% NHS) was synthesized as follows. Poly[2-(ethyl / methoxy-carbonyl-ethyl)-2-oxazoline] copolymers (DP=+ / -100) were synthesized by CROP using 60% 2-ethyl-2-oxazoline (EtOx) and 40% 2-methoxycarbonyl-ethyl-2-oxazoline (MestOx). 1H-NMR) was obtained.

[0171] The polymer containing 40% 2-methoxycarbonyl-ethyl groups was then reacted with ethanolamine to give a copolymer with 40% 2-hydroxy-ethyl-amido-ethyl groups ( 1 H-NMR). Afterwards, half of the 2-hydroxy-ethyl-amido-ethyl groups were reacted with succinic anhydride, 1 According to H-NMR, a terpolymer was obtained with 60% 2-ethyl groups, 20% 2-hydroxy-ethyl-amido-ethyl groups, and 20% 2-carboxy-ethyl-ester-ethyl-amido-ethyl groups.

[0172] Finally, the 2-carboxy-ethyl-ester-ethyl-amido-ethyl-groups were activated by N-hydroxysuccinimide (NHS) and diisopropylcarbodiimide (DIC) to obtain EL-POx, 20% NHS, corresponding to an NHS degree of functionalisation (NHS-DF) of 100%. 1 According to H-NMR, NHS-POx contained 20% NHS-ester groups.

[0173] NHS-POx was dissolved in water at 2-8 °C (60 g in 300 mL), cooled at -80 °C for 30 min and then lyophilized. The lyophilized powder thus obtained was dried at 40 °C in a Rotavap until the water content was less than 0.8 w / w%, as determined by Karl Fischer titration. This dry (white) powder was ground using a ball mill (Retch MM400) to an average particle size of 40 μm or less (D[4,3]) and vacuum sealed in alu-alu bags.

[0174] Staining of NHS-POx powder 31.25 mg of Blue No. 1 dye (CAS 3844-45-9, SpectrumChem., VWR) was dissolved in 500 mL of cold ultrapure water using a high performance dispersing device (Ultra-Turrax, IKA). After mixing (5 min), 62.5 g of NHS-POx was dissolved in the FD&C solution using a high performance dispersing machine (Ultra-Turrax, IKA). Immediately after mixing (5 min), the solution was flash frozen and subsequently freeze-dried. The freeze-dried powder was dried at 40°C in a Rotavap until the residual water content was less than 0.8 w / w% as determined by Karl Fischer titration. The dried (blue) powder was then ground using a ball mill (Retch MM400) to a blue-stained NHS-POx powder with an average particle size (D[4,3]) of 40 μm or less and vacuum sealed in an alu-alu bag. The co-lyophilized NHS-POx was 1 H-NMR spectroscopy was used to analyze. 15 mg of the co-lyophilized powder was dissolved in deuterated dimethyl sulfoxide (DMSO-d6). The sample was transferred to an NMR tube and 1 H-NMR spectra were recorded, and the amount of NHS bound to NHS-POx was calculated to be 90% to 100% on average.

[0175] Preparation of NU-POx Polyoxazolines bearing ethyl and amine groups in the alkyl side chains were synthesized by CROP of EtOx and MestOx followed by amidation of the methyl ester side chains with ethylenediamine to give poly(2-ethyl / aminoethylamidoethyl-2-oxazoline) copolymers (NU-POx).

[0176] NU-POx is 1H-NMR showed a content of 10% NH2. NU-POx was dissolved in water at 2–8 °C (60 g in 300 mL), cooled at -80 °C for 30 min and then freeze-dried. The freeze-dried powder thus obtained was dried at 40 °C in a Rotavap until the water content was less than 0.8 w / w%, as determined by Karl Fischer titration. The dried powder was ground in a knife mill (Retsch GM200) to an average particle size of 100 μm (D[4,3]) or less and vacuum-sealed in alu-alu bags.

[0177] Preparation of NHS-POx / sugar mixtures by co-lyophilization (Process A1) Co-lyophilized NHS-POx / sugar powder was prepared as follows. 15 g of sugar was dissolved in 200 mL of cold ultrapure water using a high-performance dispersion device (Ultra-Turrax, IKA). Then, after mixing (3 min), 15 g of blue-dyed NHS-POx was dissolved in the sugar mixture using a high-performance dispersion device (Ultra-Turrax, IKA). Immediately after mixing (3 min), the solution was frozen in liquid nitrogen and lyophilized.

[0178] The lyophilized powder was dried in a Rotavap at 40° C. until the residual moisture content was less than 0.8 w / w% as determined by Karl Fischer titration. The dried powder was ground in a knife mill to a particle size of 63 μm or less and vacuum sealed in an alu-alu bag.

[0179] Co-lyophilized NHS-POx / sugar (1:1 w / w) 1 H-NMR spectroscopy was used to analyze. 15 mg of the co-lyophilized powder was dissolved in deuterated dimethyl sulfoxide (DMSO-d6). The sample was transferred to an NMR tube and 1 H-NMR spectra were recorded. The NHS-DF was calculated from the obtained spectra to be 85% to 100% on average.

[0180] Preparation of NHS-POx / sugar granules (Process A2) NHS-POx / sugar granules were prepared as follows. 23 g of co-lyophilized NHS-POx / sugar from process A1 was added to a mortar. Then, 10 mL of acetone:water (95:5 v / v) was added slowly in 1 mL increments while mixing. The granules were dried under vacuum in a Rotavap at 40° C. for 1 hour and milled in a knife mill for 10 seconds. The milled granules were 1 It was dried again under reduced pressure until the acetone content was less than 0.2% and the water content was less than 0.8%, as determined by 1 H-NMR and Karl Fischer titration.

[0181] The dried granules were remilled to the desired particle size range (see below) and vacuum sealed in alu-alu bags.

[0182] NHS-POx / sugar granules (1:1 w / w) were analyzed using 1H-NMR spectroscopy. 25 mg of granules were dissolved in deuterated dimethyl sulfoxide (DMSO-d6) containing maleic acid (3 mg / mL) as an internal standard (1.0 mL), transferred to an NMR tube, and 1H-NMR spectra were recorded. The NHS-DF was calculated from the obtained spectra to be 85%-100% on average.

[0183] Preparation of NU-POx / Gelfoam / Sugar Granules (Process B1) 0.2 g NU-POx, 0.8 g Gelfoam (unless otherwise stated: GELITA-SPON powder, ex Gelita Medical AG, Germany) and 0.8 g sugar were weighed into a mortar. The excipients were granulated with 50 w / w% ultrapure water. The wet granules were dried in an oven at 70° C. until the moisture content was less than 0.5%, as determined by Karl Fischer titration. The dried granules were milled to the desired particle size range (see below). The reactivity of the granules can be controlled by adjusting the pH to 9.5 with NaOH or 9.2 with a borate buffer before drying.

[0184] Preparation of NU-POx / Gelfoam / Sugar / Surfactant Granules (Process B2) NU-POx / Gelfoam / sugar granules were prepared as described in Process B1 with the addition of surfactant dissolved in the ultrapure water used for granulation to give 0.10-0.50 w / w% surfactant in the final granules containing NHS-POx / sugar and NU-POx / Gelfoam / sugar.

[0185] Preparation of NHS-POx sugar / NU-POx / Gelfoam / sugar / surfactant powder mixture (Process C1) The powder mixture was prepared as follows. NHS-POx sugar powder (Process A2, desired particle size) and NU-POx / Gelfoam / sugar / surfactant granules (Process B1 or B2, desired particle size) were added to the vial in a 1:1 weight ratio, mixed by shaking, and vacuum sealed in an alu-alu bag.

[0186] Preparation of NHS-POx sugar / NU-POx / Gelfoam / sugar / surfactant powder mixture (Process C2) The powder mixture was prepared as follows. NHS-POx sugar powder (Process A1, particle size <63 μm) and NU-POx / Gelfoam / sugar / surfactant granules (Process B1 or B2, desired particle size) were added to a mortar in a 1:1 weight ratio, dry mixed and vacuum sealed in an alu-alu bag.

[0187] Preparation of NHS-POx sugar / NU-POx / Gelfoam / sugar / surfactant granules (Process C3). Granules were prepared as follows: NHS-POx sugar granules (Process A2, particle size <63 μm) and NU-POx / Gelfoam / sugar / surfactant granules (Process B2, particle size <63 μm) were introduced into a mortar in a weight ratio of 1:1. Then, 1 mL of acetone was added during grinding and mixing for a total of 1 mL / g.

[0188] The granules thus obtained are 1 It was dried under reduced pressure until the acetone content was less than 0.2% as determined by H-NMR. The dried granules were ground in a mortar to a particle size of 125-180 μm and vacuum sealed in an alu-alu bag.

[0189] NHS-POX / sugar granules (1:1) were analyzed using 1H-NMR spectroscopy. 25 mg of granules were dissolved in deuterated dimethyl sulfoxide (DMSO-d6) containing maleic acid (3 mg / mL) as an internal standard (1.0 mL), transferred to an NMR tube, and 1H-NMR spectra were recorded. The NHS-DF was calculated from the obtained spectra to be 85%-100% on average.

[0190] Crushing and sieving Grinding was performed using either a mortar and pestle or a knife mill (Retsch GM 200). Sieving was performed to obtain fractions with the desired particle size and particle size distribution. For this, a Retsch AS200 sieving tower was used with sieves of the following sizes: 45 μm, 63 μm, 90 μm, 125 μm, 180 μm, 250 μm and 500 μm. The powders were ground and sieved to obtain the desired particle size. The appropriate powder particle size range was obtained by sampling the desired sieved fractions.

[0191] Application of powder to punch bleeding areas, abrasion bleeding areas, and lung lesions Punch bleed (by vial): amount of powder contained in a closed vial with a diameter of 15 mm. Powder was applied by pouring directly from the vial onto the punch bleed. Once adequate coverage of the bleed was obtained, pressure was applied with 0.9% NaCl moistened gauze for 1 minute and the moistened gauze was carefully removed.

[0192] Abrasion (by bellows): A given amount of powder was applied via a bellows applicator with an applicator tube of 80 mm length. The powder was applied by spraying it in the form of a puff directly onto the lesion (abrasion) and the hemostatic effect was evaluated after 1 min. If (complete) hemostatic coverage of the abraded area was not achieved, further pressure was applied with 0.9% NaCl moistened gauze for 1 min and the moistened gauze was carefully removed.

[0193] Pulmonary Lesions: Powder was applied by hand to a 5 x 5 cm square of lung surface surrounding a standardized defect. Once uniform coverage was achieved, pressure was applied with 0.9% NaCl moistened gauze for 2 minutes, and after 1 minute hand positioning was adjusted to prevent irregularities in the final hydrogel, and the moistened gauze was carefully removed.

[0194] Hemostasis and sealing experiments Hemostatic efficacy was assessed using standardized ex vivo and in vivo pig bleeding models. All models used heparin to increase blood clotting time by approximately 2-3 fold over the activated coagulation time (ACT).

[0195] Ex vivo model: A live ex vivo pig model with fresh livers perfused with fresh heparinized blood from the slaughterhouse to replicate actual in vivo conditions as closely as possible. The livers are attached to a perfusion machine that maintains oxygenation, blood pH, temperature and blood pressure within in vivo ranges. Two livers and 10 liters of heparinized blood (5000 units / L) are collected at the slaughterhouse. The livers are transported on ice. The blood is at ambient temperature. Within 2 hours of collection, the livers are inspected for lesions, gloved and closed with cyanoacrylate glue. Perfusion parameters: flow rate 600ml / min, pressure 10-12mmHg, temperature 37℃ (+ / -1℃), carbogen 0.25 liters / min, Using a biopsy punch, create a circular bleeding lesion (8 mm in diameter) on the liver surface using a rubber onlay so that the bleeding area after the punch is always 3 mm deep, or alternatively, create an abrasion lesion (3 × 3 cm) using sandpaper (approximately 1 mm thick). After the liver is adequately perfused (check color and temperature), the specimen is examined according to the following procedure: Activate the camera. Determine site number with the camera. Use an 8mm biopsy punch. Cut the biopsy. Remove blood from the bleeding area with gauze (2 times). Collect blood with pre-weighed gauze for 30 seconds. Score the bleeding area. Apply hemostatic powder to bleeding site (punch or abrasion), in case of punch bleeding use moist gauze (saline) to distribute powder and apply pressure for 1 minute. - Observe and score the seal and hemostasis.

[0196] In vivo model: A standardized compound penetrating splenic rupture is inflicted on anesthetized pigs (domestic pig, male, weight range: 40 kg-100 kg adult). A midline laparotomy is performed to access the spleen and other organs. A scalpel is used to create n=3 subcapsular standardized lesions (10 mm x 10 mm). Hemostatic powder is applied with gentle pressure by pre-moistened gauze (saline) and held for 1 min before sealing and hemostasis are scored.

[0197] Sealing experiment A standardized ex vivo pig lung ventilation model was used to evaluate sealing performance, and more specifically aerostatic effectiveness, in the absence of blood.

[0198] Ex vivo model: Freshly harvested porcine heart-lung specimens were ordered from a slaughterhouse and transported on ice to the research facility. All excess tissue was removed, the main pulmonary artery was ligated, and the left atrial remnant was sutured. The caudal lung lobe was selectively intubated and ventilated after alveolar recruitment using a manual inflation and recruitment maneuver.

[0199] In the experimental setup, lungs were suspended in 0.9% NaCl (37°C) and photographed from below for visual leak assessment. A measurement protocol with increasing plateau ventilation pressure (Pplat) was performed during each measurement. Ventilator settings were pressure-controlled ventilation, respiratory rate 12 / min, inspiration-to-expiration ratio 1:2, positive end-expiratory pressure (PEEP) 5 cmH2O, and pressure above PEEP 5 cmH2O. Every 90 seconds, PEEP was increased by 5 cmH2O to a Pplat of 40 cmH2O. First, a baseline measurement was performed using this measurement protocol to measure compliance. With the lungs inflated with 10 cmH2O PEEP, a standardized 25 x 25 mm superficial pleural defect was then created on the dorsal aspect of the caudal lobe by cutting the pleural edge using a sanding wheel attachment on a Dremel at a 45° angle and then carefully peeling back the central pleura using forceps and scissors. Baseline leakage measurements were then performed using the same protocol. · Sealing powder was then applied by hand to a 5x5cm square of lung surface surrounding the standardized defect while the lung was inflated with a PEEP of 0-5cmH2O (if air leaked through the dry powder, PEEP was reduced until this was resolved). Once uniform coverage was achieved, pressure was applied with 0.9% NaCl wet gauze for 2 minutes, adjusting the hand position after 1 minute to prevent irregularities in the final hydrogel. After careful removal of the gauze, the hydrogel was allowed to cure for an additional 5 minutes in the measuring apparatus (0.9% NaCl, 37°C). Quantitative leakage (Pplat) was measured and failure mode was assessed visually according to Macchiarini et al. (Macchiarini P, Wain J, Almy S, Dartevelle P. Experimental and clinical evaluation of a new synthetic, absorbable sealant to reduce air leaks in thoracic operations. J Thorac Cardiovasc Surg. 1999;117(4):751-8).

[0200] Powder Occlusion Score Rating System for Bleeding (based on adhesion and cohesion assessment 1 minute after application): +++Very strong seal (seal breaks only when more than 80% by weight of powder is rubbed off) ++Strong seal (seal breaks when part of powder is rubbed off) + Good seal (seal breaks when powder is mechanically manipulated) + / - Moderate seal (seal breaks when surrounding tissue is manipulated) -Sealing is not achieved

[0201] Powder Hemostatic Score Rating System for Bleeding 1 Minute After Application: +++Very strong hemostasis (powder is filled with blood only at the powder-lesion interface; bleeding has stopped) ++Strong hemostasis (powder is partially filled with blood; there is a layer of blood-free powder on top; bleeding has stopped) + Good hemostasis (powder is completely filled with blood; bleeding has stopped) + / - Moderate hemostasis (powder fills completely with blood, some blood passes through) - Hemostasis not achieved (bleeding does not stop)

[0202] Powder wetting score for bleeding is measured by applying saline (0.9% NaCl) soaked gauze for 1 minute and then removing it (wetting is scored 4 minutes after gauze removal by measuring the depth of penetration into the powder layer). -Saline is not easily absorbed into the powder layer, only the surface of the powder layer is wet, and saline droplets easily roll off the powder surface. + / - Saline partially penetrated the powder layer +Saline completely penetrated the powder layer

[0203] Comparative example A EL-POx was dry mixed by co-grinding (using a mortar and pestle) with either Gelfoam alone (EL-POx:Gelfoam=1:0.8 w / w) or Gelfoam and NU-POx (EL-POx:Gelfoam:Nu-POx=1:0.8:0.2 w / w). The tap density of both powders was less than 0.2 g / mL.

[0204] The sealing and hemostatic properties of these two powders and two commercially available hemostatic powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in 1 gram quantities.

[0205] The test results are summarized in Table 1.

[0206] [Table 1] 1 GELITA-SPON® powder, Gelita Medical AG, Germany 2 Arista AH, Bard, USA

[0207] Example 2 A powder mixture (powder mixture 1) was prepared by process C2 using the powder obtained by process A1 (EL-POX:sugar=1:1 w / w) and the powder obtained by process B1. Trehalose was used as the sugar component in both powders. A powder mixture (powder mixture 2) of the same composition was prepared by process C1 using the powder obtained by process A2 (EL-POX:sugar=1:1 w / w, granulated using acetone / water (95:5) as the granulation liquid) and the powder obtained by process B1.

[0208] The sealing and hemostatic properties of these two sealing powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in an amount of 0.5 grams.

[0209] The test results are summarized in Table 2.

[0210] [Table 2]

[0211] Example 3 Three different powder mixtures were prepared by Process C1 using the powder obtained by Process A2 (EL-POX:sugar=1:1 w / w) and three different powders obtained by Process B1. All powders used trehalose as the sugar component.

[0212] The three powder mixtures differed only in that the powders obtained by process B1 contained different amounts of NU-POx.

[0213] [Table 3]

[0214] The sealing and hemostatic properties of these two sealing powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in an amount of 0.5 grams.

[0215] The test results are summarized in Table 3.

[0216] [Table 4]

[0217] Example 4 Two different powders were prepared by mixing 1 part by weight of NHS-POx powder (without sugar) with either 2 parts by weight of powder obtained by process B1 containing trehalose or 1 part by weight of powder obtained by process B1 without sugar.

[0218] The composition of the powder obtained by process B1 was as follows:

[0219] [Table 5]

[0220] The sealing and hemostatic properties of these two sealing powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in an amount of 0.5 grams using a bellows applicator (Surgicel®).

[0221] The test results are summarized in Table 4.

[0222] [Table 6]

[0223] Powder Mix 1 could be easily applied by a bellows applicator. However, Powder Mix 2 was difficult to apply because the powder particles were very fluffy. To allow for comparability of sealing, hemostatic and wetting properties, Powder Mix 2 was applied by tube in this experiment.

[0224] Example 5 Five different powder mixtures were prepared by Process C1 using the powder obtained by Process A2 (EL-POX:sugar=1:1 w / w) and five different powders obtained by Process B1. All powders used trehalose as the sugar component.

[0225] The five different powder mixtures differed only in that the powders obtained by process B1 contained different amounts of trehalose.

[0226] [Table 7]

[0227] The sealing and hemostatic properties of these two sealing powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in 0.5 gram quantities using a bellows applicator.

[0228] The test results are summarized in Table 5.

[0229] [Table 8]

[0230] Powder mixes 1, 3, 4 and 5 could be easily applied with the bellows applicator. Powder mix 2 was less easy to apply as the particles were very fluffy.

[0231] Example 6 Three different powder mixtures were prepared by Process C1 using the powder obtained by Process A2 (EL-POX:sugar=1:1 w / w) and three different powders obtained by Process B1. The three different powders obtained by Process B1 differed only in the type of sugar used. In all cases, NU-POx, Gelfoam and sugar were present in the powders from Process B in a weight ratio of 2:8:8.

[0232] [Table 9]

[0233] The sealing and hemostatic properties of these two sealing powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in an amount of 0.5 grams.

[0234] The test results are summarized in Table 6.

[0235] [Table 10]

[0236] Example 7 Four different powder mixtures were prepared by process C1 using a powder obtained by process A2 (EL-POX:sugar=1:1 w / w), one powder obtained by process B1, and three different powders obtained by process B2. The three different powders obtained by process B2 differed in the amount of surfactant (Pluronic F-127) used. Trehalose was applied as the sugar component in all powders.

[0237] [Table 11]

[0238] The sealing and hemostatic properties of these two sealing powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in an amount of 0.5 grams.

[0239] The test results are summarized in Table 7.

[0240] [Table 12]

[0241] Example 8 Example 7 was repeated, except that in this example sodium dodecyl sulfate (SDS) was used as the surfactant.

[0242] [Table 13]

[0243] The sealing and hemostatic properties of these two sealing powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in an amount of 0.5 grams.

[0244] The test results are summarized in Table 8.

[0245] [Table 14]

[0246] Example 9 In this example, Example 7 was repeated, except that poloxamer P-188 was used as the surfactant.

[0247] [Table 15]

[0248] The sealing and hemostatic properties of these two sealing powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in an amount of 0.5 grams.

[0249] The test results are summarized in Table 9.

[0250] [Table 16]

[0251] Example 10 Three different powder mixtures were prepared by Process C1 using one powder obtained by Process A2 (EL-POX:sugar=1:1 w / w) and three different powders obtained by Process B1. The three powders obtained by Process B2 differed in that they contained different types of gel foam.

[0252] [Table 17] 1 Gelita Medical AG, Germany 2 Mascia Brunelli Spa, Italy 3 Aegis Lifesciences PVT Ltd, India

[0253] The sealing and hemostatic properties of these sealing powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in an amount of 1.0 gram.

[0254] The test results are summarized in Table 10.

[0255] [Table 18]

[0256] Example 11 The powder obtained by process A2 (EL-POX:sugar=1:1 w / w) and the powder obtained by process B1 were used to prepare different powder mixtures by process C1. Trehalose was applied as the sugar component in all powders. The particle size of each powder was changed as shown in Table 11.

[0257] The sealing and hemostatic properties of these sealing powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in an amount of 0.5 grams.

[0258] The test results are summarized in Table 11.

[0259] [Table 19]

[0260] Example 12 Different powder mixtures were prepared using the powder obtained by process A1 or A2 (EL-POX:sugar=1:1 w / w) and the powder obtained by process B2 by powder mixing process C1 or C2 or by granulation process C3.

[0261] [Table 20]

[0262] All powders applied trehalose as the sugar component.

[0263] The sealing and hemostatic properties of these two sealing powders were tested in an ex vivo porcine liver system (heparinized). The powders were applied in an amount of 0.5 grams.

[0264] The test results are summarized in Table 12.

[0265] [Table 21]

[0266] Example 13 In vivo tests were carried out on porcine spleen (heparinized) using powders obtained by process A2 (EL-POX:sugar=1:1 w / w) and powders obtained by process B1, and using powder mixtures (0.5 grams) prepared by process C1. Trehalose was applied as the sugar component in all powders. The powders differed only in particle size. The test results are summarized in Table 13.

[0267] [Table 22]

[0268] Example 14 The performance of the powder blend of Example 12 was also evaluated in an in vivo spleen study (heparinized) using 0.5 grams of the powder blend, and the results are shown in Table 14.

[0269] [Table 23]

[0270] Example 15 Ex vivo tests were carried out on porcine livers (heparinized) with abraded lesions (3 x 3 cm). The sealing powders used (1 gram) were prepared by dry mixing process C1 (powder mix 1) or by granulation process C3 (granule 2). In both cases, powders obtained by process A2 and powders obtained by process B2 were used. The powders were administered using a bellows applicator. In all powders, trehalose was applied as the sugar component.

[0271] The test results are summarized in Table 15.

[0272] [Table 24]

[0273] Example 16 The sealing properties of the sealing powder in the absence of blood were evaluated in the ex vivo ventilated lung model described herein above. After application of the sealing powder, the pressure at which leakage began was recorded.

[0274] The encapsulation powders tested were obtained by dry blending (Process C1) or granulation (Process C3) of NHS-POx-containing powders and NU-POx-containing powders. The NHS-POx-containing powders consisted of NHS-POx or were granules of NHS-POx and trehalose obtained by Process A2. The NU-POx-containing powders further contained gelfoam and trehalose and were granules obtained by Process B1 or B2.

[0275] The results of each test are summarized in Table 16.

[0276] [Table 25] 1 Pluronic F-177

[0277] Example 17 Granules were prepared by granulation process C3 using the powder obtained by process A2 (EL-POX:trehalose = 1:1 w / w) and the powder obtained by process B2 (particles containing NU-POx), except that in each case the gel foam in the latter powder was replaced by another water-insoluble polymer containing reactive nucleophilic groups as shown below.

[0278] [Table 26] 1 ex Sigma Aldrich, MW 100,000-300,000, 85% deacetylation degree 2 Prepared according to the procedure described in WO 2021 / 009014 (page 29, lines 3-14).

[0279] The sealing and hemostatic properties of these two sealing powders were tested in an ex vivo porcine liver system (heparinized). Each granule was applied in an amount of 0.5 grams. The test was performed in duplicate. The test results are summarized in Table 17.

[0280] [Table 27]

[0281] Comparative example B The powder obtained by process A2 (EL-POX:trehalose=1:1 w / w) and the powder obtained by process B2 (particles containing NU-POx) were used to prepare granules by granulation process C3, except that in this case gelfoam was replaced by oxidized absorbable cellulose (GeltaCel®, manufactured by Gelita Medical GmbH).

[0282] The sealing and hemostatic properties of the granules were tested in an ex vivo pig liver system (heparinized). Granules were applied in an amount of 0.5 grams. The test was performed in duplicate. The test results are summarized in Table 18.

[0283] [Table 28]

[0284] Example 18 The powder obtained by process A2 (EL-POX:sugar=1:1 w / w) and the powder obtained by process B2 (particles containing NU-POx) were used to prepare granules by granulation process C3, except that in this case, trehalose in the first powder was replaced with mannitol.

[0285] The sealing and hemostatic properties of the granules were tested in an ex vivo pig liver system (heparinized). Granules were applied in an amount of 0.5 grams. The test was performed in duplicate. The test results are summarized in Table 19.

[0286] [Table 29]

[0287] Example 19 Granules were prepared by granulation process C3 using the powder obtained by process A2 (EL-POX:sugar=1:1 w / w) and the powder obtained by process B2, except that in the latter powder, 8-arm polyethylene glycol with 8 amine groups (8-arm PEG-NH@ex Creative PEGWorks) was used instead of NU-POx.

[0288] The sealing and hemostatic properties of the granules were tested in an ex vivo pig liver system (heparinized). Granules were applied in an amount of 0.5 grams. The test was performed in duplicate. The test results are summarized in Table 20.

[0289] [Table 30]

[0290] [Embodiment] (1) A bioabsorbable encapsulating powder comprising: (a) at least 5% by weight of a water-soluble electrophilic polymer having at least three reactive electrophilic groups capable of reacting with amine groups under formation of covalent bonds; (b) 1-50 wt. % of a water soluble nucleophilic crosslinker having at least two reactive nucleophilic groups capable of reacting in the presence of water with the reactive electrophilic groups of the electrophilic polymer under formation of a covalent bond between the electrophilic polymer and the nucleophilic crosslinker; (c) 1-60 wt. % water-absorbing particles, the water-absorbing particles comprising at least 50 wt. % water-insoluble polymers containing reactive nucleophilic groups selected from amine groups, thiol groups, and combinations thereof, calculated by the weight of the water-absorbing particles; (d) 10 to 75% by weight of a water-soluble dispersant that is solid at 20° C., the water-soluble dispersant being selected from monosaccharides, disaccharides, oligosaccharides, sugar alcohols, and combinations thereof; the combination of components (a), (b), (c) and (d) constitutes at least 60% by weight of the encapsulating powder; The encapsulating powder has a tap density in the range of 0.3 to 0.9 g / ml; At least 90% by weight of the powder has a diameter less than 600 μm, and no more than 10% by weight of the powder has a diameter less than 10 μm; The components (a), (b), (c) and (d) may be contained in the same particle or in different particles. (2) The powder of embodiment 1, wherein the electrophilic polymer is selected from electrophilic polyoxazolines, electrophilic polyethylene glycols, and combinations thereof. (3) The powder according to any one of the preceding claims, wherein the nucleophilic crosslinking agent is selected from nucleophilic polyoxazolines, nucleophilic polyethylene glycols, polyethyleneimines, and combinations thereof. (4) The powder according to any one of the preceding claims, wherein the water-insoluble polymer containing a reactive nucleophilic group is selected from proteins, chitosan, and combinations thereof. (5) The powder according to any one of the preceding claims, wherein the ratio of the total number of reactive electrophilic groups provided by the electrophilic polymer to the total number of reactive nucleophilic groups provided by the nucleophilic crosslinker is in the range of 1:0.05 to 1:0.4.

[0291] (6) The powder according to any one of the preceding claims, wherein the powder comprises 20-80% by weight of particles containing only components (a) and (d) and 20-80% by weight of particles containing only components (b), (c) and (d). (7) The powder of embodiment 6, wherein the particles containing only components (a) and (d) and the particles containing only components (b), (c), and (d) together constitute at least 60% by weight of the encapsulating powder. (8) The powder of any one of the preceding claims, wherein the powder contains at least 60% by weight of particles containing each of components (a), (b), (c), and (d). (9) The powder according to embodiment 8, wherein the powder contains at least 50% by weight of the particles containing each of components (a), (b), (c), and (d) in the form of agglomerates of sub-particles A containing only components (a) and (d) and sub-particles B containing only components (a), (c), and (d). (10) A method for preparing the bioabsorbable encapsulating powder according to any one of embodiments 1 to 9, comprising the steps of: (a) providing a particle A comprising the electrophilic polymer and the water-soluble dispersant; (b) providing particles B comprising the nucleophilic crosslinker, the water-absorbing particles, and the water-soluble dispersant; (c) combining said particles A and said particles B.

[0292] 11. The method of claim 10, wherein particles A and particles B are combined into an aggregate. (12) An apparatus for applying sealing powder, comprising: A reservoir containing the bioabsorbable encapsulating powder according to any one of the first to ninth embodiments; an elongated hollow tubular structure having a proximal end and a distal end, the distal end having a powder outlet and the proximal end connected to the reservoir; a manual air pump arranged to generate an air flow that carries powder from the reservoir, through the elongated hollow tubular structure and through the powder outlet. (13) A biocompatible and flexible hemostatic sheet, comprising: a cohesive fibrous carrier structure comprising three-dimensional interconnected interstitial spaces; The bioabsorbable encapsulating powder according to any one of embodiments 1 to 9, A hemostatic sheet, wherein the sealing powder is distributed within the interstitial spaces and / or fixed onto the fibrous carrier structure. (14) A kit of parts for preparing a bioabsorbable encapsulant suspension, comprising: a first container or compartment containing a biocompatible liquid; A second container or compartment comprising the bioabsorbable sealing powder according to any one of embodiments 1 to 9. (15) A bioabsorbable encapsulating suspension comprising: a biocompatible continuous liquid non-aqueous phase; a dispersed phase comprising the bioabsorbable encapsulating powder according to any one of embodiments 1 to 9,

Claims

1. A bioabsorbable encapsulating powder comprising: (a) at least 5% by weight of a water soluble electrophilic polymer, the water soluble electrophilic polymer having at least three reactive electrophilic groups capable of reacting with amine groups under formation of covalent bonds; (b) 1-50 wt. % of a water soluble nucleophilic crosslinker having at least two reactive nucleophilic groups capable of reacting in the presence of water with the reactive electrophilic groups of the electrophilic polymer under formation of a covalent bond between the electrophilic polymer and the nucleophilic crosslinker; (c) 1-60% by weight of water-absorbing particles, the water-absorbing particles comprising at least 50% by weight, calculated by the weight of the water-absorbing particles, of a water-insoluble polymer containing reactive nucleophilic groups selected from amine groups, thiol groups, and combinations thereof; (d) 10 to 75% by weight of a water-soluble dispersing agent that is solid at 20° C., the water-soluble dispersing agent being selected from monosaccharides, disaccharides, oligosaccharides, sugar alcohols, and combinations thereof; the combination of components (a), (b), (c) and (d) comprises at least 60% by weight of said sealing powder; the encapsulating powder has a tap density in the range of 0.3 to 0.9 g / ml; At least 90% by weight of the powder has a diameter less than 600 μm, and no more than 10% by weight of the powder has a diameter less than 10 μm; The bioabsorbable encapsulating powder, wherein the components (a), (b), (c) and (d) may be contained in the same particle or in different particles.

2. 2. The powder of claim 1, wherein the electrophilic polymer is selected from electrophilic polyoxazolines, electrophilic polyethylene glycols, and combinations thereof.

3. 3. The powder of claim 1 or 2, wherein the nucleophilic crosslinking agent is selected from nucleophilic polyoxazolines, nucleophilic polyethylene glycols, polyethyleneimines, and combinations thereof.

4. 4. The powder according to claim 1, wherein the water-insoluble polymer containing reactive nucleophilic groups is selected from proteins, chitosan and combinations thereof.

5. 5. The powder according to any one of claims 1 to 4, wherein the ratio of the total number of reactive electrophilic groups provided by the electrophilic polymer to the total number of reactive nucleophilic groups provided by the nucleophilic crosslinker is in the range of 1:0.05 to 1:0.

4.

6. 6. The powder according to claim 1, wherein the powder comprises 20-80% by weight of particles containing only components (a) and (d) and 20-80% by weight of particles containing only components (b), (c) and (d).

7. 7. The powder of claim 6, wherein the particles containing only components (a) and (d) and the particles containing only components (b), (c) and (d) together constitute at least 60% by weight of the encapsulating powder.

8. 6. The powder of claim 1, wherein the powder contains at least 60% by weight of particles containing each of components (a), (b), (c) and (d).

9. 9. The powder of claim 8, wherein the powder contains at least 50% by weight of the particles containing each of the components (a), (b), (c) and (d) in the form of agglomerates of sub-particles A containing only components (a) and (d) and sub-particles B containing only components (a), (c) and (d).

10. A method for preparing the bioabsorbable sealing powder according to any one of claims 1 to 9, comprising the steps of: (a) providing a particle A comprising the electrophilic polymer and the water-soluble dispersant; (b) providing a particle B comprising the nucleophilic crosslinker, the water-absorbing particle, and the water-soluble dispersant; (c) combining said particles A with said particles B.

11. The method of claim 10, wherein said particles A and said particles B are combined into an agglomerate.

12. 1. An apparatus for applying sealing powder, comprising: A reservoir containing the bioabsorbable sealing powder according to any one of claims 1 to 9; an elongated hollow tubular structure having a proximal end and a distal end, the distal end having a powder outlet and the proximal end connected to the reservoir; a manual air pump arranged to generate an air flow that carries powder from the reservoir, through the elongated hollow tubular structure and through the powder outlet.

13. A biocompatible, flexible hemostatic sheet comprising: - a cohesive fibrous carrier structure comprising three-dimensional interconnected interstitial spaces; - The bioabsorbable sealing powder according to any one of claims 1 to 9, A hemostatic sheet, wherein the sealing powder is distributed within the interstitial spaces and / or fixed onto the fibrous carrier structure.

14. 1. A kit of parts for preparing a bioabsorbable encapsulating suspension comprising: a first container or compartment containing a biocompatible liquid; - a second container or compartment containing a bioabsorbable sealing powder according to any one of claims 1 to 9.

15. 1. A bioabsorbable encapsulating suspension comprising: a biocompatible continuous liquid non-aqueous phase; a dispersed phase comprising the bioabsorbable encapsulating powder of any one of claims 1 to 9.

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