Submucosal lift and hemostatic closure hydrogels

Abstract

In some aspects, the present invention relates to injectable polysaccharide-based hydrogels comprising an anionic polysaccharide, a cationic crosslinker, and a hemostatic. In some aspects, the invention relates to medical devices comprising such injectable polysaccharide-based hydrogels, kits comprising such injectable polysaccharide-based hydrogels, and methods of using such injectable polysaccharide-based hydrogels.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 337,726, filed on May 3, 2022, the disclosure of which is incorporated herein by reference. Technical Field

[0002] The present disclosure relates to injectable gels that can be used in various medical procedures, including as lifting agents for endoscopic mucosal resection and dissection procedures. Background Art

[0003] Injectable compositions are generally used to separate a structure from another structure, so as to separate, lift and / or stabilize the first structure, thereby safely, quickly and effectively perform medical diagnosis or treatment steps. For example, endoscopic surgery (such as endoscopic mucosal resection (EMR), endoscopic submucosal stripping (ESD), colon polypectomy and peroral endoscopic myotomy (POEM)) is generally performed to detect and remove malignant and precancerous lesions, tumors and / or other unhealthy tissues in the mucosal layer and submucosal layer of the gastrointestinal tract (GI). In order to reduce the risk of gastrointestinal perforation, health care providers usually separate the submucosal layer from the muscular layer below before performing excision or stripping surgery. The typical method of setting up this separation is to inject liquid between the muscular layer and the submucosal tissue layer.

[0004] Surgical removal of tissue creates internal wounds that bleed easily. A common step in surgery is to obtain adequate mucosal closure. Several techniques are available for mucosal closure, including the use of endoscopic clips and / or endoscopic suturing. Summary of the invention

[0005] The present disclosure relates to injectable hydrogel compositions that can be used in various medical procedures. The injectable hydrogel compositions are suitable for providing submucosal elevation and hemostatic closure treatment to the immediate tissue area after excision or dissection.

[0006] In some aspects, the present disclosure relates to an injectable polysaccharide-based hydrogel comprising an anionic polysaccharide, a cationic cross-linking agent, and a hemostatic agent.

[0007] In some embodiments, the anionic polysaccharide contains repeating units of glucuronic acid. In a specific example, the anionic polysaccharide includes gellan gum.

[0008] In some embodiments that may be used in combination with the preceding aspects and embodiments, the concentration of the anionic polysaccharide ranges from about 0.010% to about 2.5% relative to the total weight of the injectable polysaccharide-based hydrogel.

[0009] In some embodiments that may be used in combination with the preceding aspects and embodiments, the cationic crosslinker comprises a salt comprising a divalent metal cation, and / or the crosslinker comprises a branched polyamine comprising two or more primary amine groups that are positively charged at the pH of the hydrogel.

[0010] In some embodiments that may be used in combination with the preceding aspects and embodiments, the concentration of the cationic crosslinker ranges from about 0.005% to about 2.5% relative to the total weight of the injectable polysaccharide-based hydrogel.

[0011] In some embodiments that can be used in combination with the foregoing aspects and embodiments, the hemostatic agent is selected from organic polymer hemostatic agents, small molecule organic hemostatic agents, macromolecular organic hemostatic agents, and inorganic hemostatic agents. In specific embodiments, the hemostatic agent can be selected from chitosan, hydroxyapatite, or tranexamic acid.

[0012] In some embodiments that may be used in combination with the preceding aspects and embodiments, the hemostatic agent is in particulate form and has an average particle size of less than 50,000 nm.

[0013] In some embodiments that may be used in conjunction with the foregoing aspects and embodiments, the concentration of the hemostatic agent ranges from about 5% to about 50% relative to the total weight of the injectable polysaccharide-based hydrogel.

[0014] In some embodiments that may be used in combination with the preceding aspects and embodiments, the injectable polysaccharide-based hydrogel further comprises a colorant.

[0015] In some aspects, the present disclosure relates to a medical device comprising a reservoir containing the injectable polysaccharide-based hydrogel according to any of the preceding aspects and embodiments.

[0016] In some embodiments, the reservoir is a syringe barrel.

[0017] In some embodiments, the medical device comprises a needle through which the injectable polysaccharide-based hydrogel is injected.

[0018] In some aspects, the present disclosure relates to use of the medical device according to any of the above aspects and embodiments in a medical procedure for elevating an upper mucosal layer from an underlying layer.

[0019] In some aspects, the present disclosure relates to a method for separating and lifting an upper mucosal layer from a lower layer, the method comprising injecting the injectable polysaccharide-based hydrogel according to any of the foregoing aspects and embodiments into a target treatment site between the upper mucosal layer and the lower layer through a needle.

[0020] In some embodiments, the method further comprises removing tissue protruding through the injectable polysaccharide-based hydrogel.

[0021] In some embodiments, the method is performed as part of an endoscopic mucosal resection procedure or an endoscopic submucosal dissection procedure.

[0022] In some embodiments, the method is performed using a medical device further comprising a flexible tube coupling the syringe barrel to the needle, and the injectable polysaccharide-based hydrogel is injected from the syringe barrel, through the flexible tube, through the needle and into the target site.

[0023] In some aspects, the present disclosure relates to a kit comprising a medical device according to any of the preceding aspects and embodiments and one or more items selected from (a) an endoscopic injection needle, (b) a tissue resection device, (c) a tissue retrieval device, and (d) an endoscope, located in a suitable packaging material. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figures 1A to 1C An exemplary medical device according to some aspects of the present disclosure is shown.

[0025] Figure 2A-2E An exemplary tissue resection procedure according to some aspects of the present disclosure is shown.

[0026] Figure 3 Shown is the recovery of 6-aminohexanoic acid in D-PBS supernatant over time according to one aspect of the present disclosure.

[0027] Figure 4 Shown is the recovery of tranexamic acid in D-PBS supernatant over time according to one aspect of the present disclosure.

[0028] Figure 5 is a photomicrograph of a particulate hemostat having a core comprising a chitosan salt and a shell comprising a tripolyphosphate salt.

[0029] Figure 6 is a graph of particle size distribution, bulk density (%) versus particle size (μm) for a collection of hemostatic particles having a core comprising a chitosan salt and a shell comprising a tripolyphosphate salt. DETAILED DESCRIPTION

[0030] The present disclosure relates to a polysaccharide-based hydrogel containing a hemostatic agent at the point of application (dosing site). The hydrogel can lift tissue to facilitate surgical resection. The hydrogel also has hemostatic properties to reduce or prevent bleeding at the surgical site. In this way, there is no need for intervention with clips or sutures. In addition, the hydrogel can reduce the incidence of intraoperative bleeding in surrounding tissues, which may occur when clips or sutures are removed after surgery.

[0031] According to various aspects of the present disclosure, the polysaccharide-based hydrogel may include a polysaccharide, a cross-linking agent, and a hemostatic agent at the point of administration. In some embodiments, the polysaccharide, the cross-linking agent, and the hemostatic agent are provided in the form of a single injectable composition. In some embodiments, the polysaccharide is cross-linked to form a hydrogel in a reservoir and is injected into the patient's body from the reservoir in the form of a hydrogel.

[0032] In some embodiments, a first injectable composition comprising a polysaccharide and a cross-linking agent is co-administered with a second injectable composition comprising a hemostatic agent.

[0033] There are a variety of options for administering the polysaccharide, cross-linking agent, and hemostatic agent to the target site of the patient, including the following: (a) particles of the hemostatic agent can be suspended in a hydrogel comprising the polysaccharide and the cross-linking agent, (b) the hemostatic agent can be dissolved in a hydrogel comprising the polysaccharide and the cross-linking agent, (c) an injectable composition comprising the hemostatic agent (wherein particles of the hemostatic agent are suspended in a liquid or hydrogel) can be co-administered (dosed) with an injectable hydrogel composition comprising the polysaccharide and the cross-linking agent, (d) an injectable composition comprising the hemostatic agent (wherein the hemostatic agent is dissolved in a liquid or hydrogel) can be co-administered with an injectable hydrogel composition comprising the polysaccharide and the cross-linking agent, or (e) the hemostatic agent can be in a dry state (e.g., as pure particles, coated particles, etc.) and pre-mixed with a hydrogel composition comprising the polysaccharide and the cross-linking agent prior to administration.

[0034] The polysaccharide that is suitable for forming the injectable composition of the present disclosure includes natural polysaccharide (for example, natural gum, such as plant gum and / or microbial gum) and synthetic polysaccharide.The polysaccharide in the composition of the present disclosure is generally anionic polysaccharide.The non-limiting example of polysaccharide includes anionic polysaccharide containing glucuronic acid repeating unit, for example gellan gum, alginate and xanthan gum etc.

[0035] In various embodiments, gellan gum may be preferred.As used herein, "gellan gum" refers to a polysaccharide (for example, produced by Sphingomonas bacteria), and has a general structure formed by four sugar repeating units connected together: two D-glucose residues, an L-rhamnose (L-rhamnose) residue and a D-glucuronic acid residue.Polysaccharide may include one or more types of gellan gum, such as natural gellan gum, deacetylated gellan gum or its mixture.Natural gellan gum may include two acyl groups (for example, acetyl and glyceryl), which are bound to the glucose residue adjacent to the glucuronic acid residue.These acyl groups can be removed under alkaline conditions to produce deacetylated gellan gum, and compared with natural gellan gum, the deacetylated gellan gum has different stability and plasticity.For example, natural gellan gum usually forms a softer, more elastic and thermoreversible gel, and deacetylated gellan gum usually forms a harder, more inelastic and more thermotolerant gel.In at least one embodiment, injectable composition comprises deacetylated gellan gum. Additional information about polysaccharide hydrogels can be found, for example, in U.S. Patent Application Publication Nos. 2019 / 0247301, 2018 / 0021252, and 2017 / 0281862, the disclosures of which are hereby incorporated herein by reference.

[0036] Some microbial extracts may contain endotoxins, such as lipopolysaccharides from bacteria bound to polysaccharide structures. In some embodiments, polysaccharides may be selected to minimize or eliminate the introduction of endotoxins in the composition. In some instances, the endotoxin level of the polysaccharide may be 20 endotoxin units (EU) or lower. Bacterial endotoxin levels can be measured, for example, using a limulus amebocyte lysate (LAL) test. Alternatively or additionally, the polysaccharide may be treated to reduce or eliminate the concentration of endotoxins before being used in the compositions disclosed herein. For example, the composition may contain a polysaccharide of microbial origin that has been treated to reduce the amount of endotoxin present so that the resulting composition is pharmaceutically acceptable and meets applicable government regulatory standards.

[0037] In some embodiments, the concentration of the polysaccharide relative to the total weight of the polysaccharide-based hydrogel at the point of application ranges from about 0.01% or less to about 2.5% or more. For example, the concentration of the polysaccharide can range from about 0.010% to about 0.025% to about 0.05% to about 0.10% to about 0.25% to about 0.5% to about 0.75% to about 1.0% to about 1.25% to about 1.5% to about 1.75% to about 2.0% to about 2.25% to about 2.5% (in other words, between any two or the foregoing values) relative to the total weight of the polysaccharide-based hydrogel at the point of application.

[0038] Cross-linking agents suitable for forming the polysaccharide-based hydrogels of the present disclosure include covalent cross-linking agents and / or ionic cross-linking agents. The cross-linking agents in the injectable compositions of the present disclosure more typically include multivalent cationic cross-linking agents. In particularly useful embodiments, the injectable compositions may include salts containing divalent cations. Non-limiting examples of such salts include salts containing divalent metal cations (e.g., calcium and / or magnesium cations), such as calcium chloride (CaCl 2 ), magnesium sulfate (MgSO 4 ), magnesium chloride (MgCl 2 ), any hydrate thereof and any mixture thereof. In a specific example, the salt with a divalent cation includes calcium chloride or a hydrate thereof, such as calcium chloride dihydrate. In some embodiments, the cross-linking agent may include a branched polyamine including two or more primary amine groups that are positively charged at the pH of the hydrogel, wherein the branched polyamine is ionically cross-linked with the polysaccharide. Non-limiting examples of such branched polyamines include trilysine, tetralysine, pentalysine, tris(aminoalkyl)amine (e.g., tris(2-aminoethyl)amine, tris(aminoalkyl)alkane (e.g., 1,1,1-tris(aminomethyl)ethane), and any mixture thereof.

[0039] In some cases, the polysaccharide-based hydrogel may include at least one salt comprising a monovalent cation and at least one salt comprising a divalent cation. For example, an injectable composition may include at least one sodium or potassium salt and at least one calcium or magnesium salt, such as NaCl and CaCl. 2 , or NaCl and MgCl 2 , or KCl and CaCl 2 , or KCl and MgCl 2 Etc. In addition, for example, the injectable composition may comprise at least one monovalent salt selected from sodium chloride, potassium chloride, sodium dihydrogen phosphate, potassium hydrogen phosphate, sodium gluconate or sodium acetate trihydrate in combination with at least one salt selected from calcium chloride, magnesium sulfate or magnesium chloride.

[0040] In some embodiments, the concentration of the salt of the divalent cation ranges from about 0.005% or less to about 0.200% or more relative to the total weight of the polysaccharide-based hydrogel at the point of application. For example, the concentration of the salt with a divalent cation can range from about 0.005% to about 0.010% to about 0.015% to about 0.020% to about 0.025% to about 0.030% to about 0.040% to about 0.050% to about 0.075% to about 0.100% to about 0.150% to about 0.200% relative to the total weight of the polysaccharide-based hydrogel at the point of application.

[0041] In some embodiments, the concentration of the salt with a monovalent cation ranges from about 0.1% or less to about 5.0% or more relative to the total weight of the polysaccharide-based hydrogel at the point of application. For example, the concentration of the salt with a monovalent cation can range from about 0.10% to about 0.25% to about 0.50% to about 0.75% to about 1.0% to about 1.5% to about 2.0% to about 5.0% relative to the total weight of the polysaccharide-based hydrogel at the point of application.

[0042] In addition, for example, the composition may include a saline solution having an osmotic pressure range of about 240mOsmol / kg to about 340mOsmol / kg (e.g., 290mOsmol / kg ± 50mOsmol / kg), such as about 250mOsmol / kg to about 320mOsmol / kg, or about 280mOsmol / kg to about 300mOs-mol / kg. The solution may be physiologically compatible, such as having an electrolyte level, osmotic pressure, and pH suitable for injection into a patient. A suitable base (e.g., sodium hydroxide) may be used to increase the pH or and / or a suitable acid (e.g., hydrochloric acid) may be used to adjust the pH of the solution, or the pH of the solution may be adjusted by other means or using other substances to provide a biocompatible composition.

[0043] As previously mentioned, in addition to the polysaccharide and the cross-linking agent, the polysaccharide-based hydrogel of the present disclosure also comprises a hemostatic agent at the point of application.

[0044] The present invention may use any suitable hemostatic agent, including organic polymer hemostatic agents, small molecule hemostatic agents, inorganic hemostatic agents or macromolecular hemostatic agents.

[0045] Organic polymer hemostatic agents include chitosan, chitosan derivatives, dextran and dextran derivatives, etc.

[0046] Chitosan is a modified polysaccharide containing randomly distributed β-(1→4) linked D-glucosamine (deacetylated units) and N-acetyl-D-glucosamine (acetyl units). Chitosan is commercially produced by alkaline N-deacetylation of chitin, a cellulosic polymer consisting primarily of unbranched chains of modified glucose, specifically N-acetyl-D-glucosamine. The degree of deacetylation of commercial chitosan typically ranges from 60% to 70% to 80% to 90% to 100%, although essentially any degree of deacetylation is possible. The molecular weight range of commercial chitosan includes low molecular weight chitosan (e.g., molecular weight range of 10 kDa to 190 kDa), medium molecular weight chitosan (e.g., molecular weight range of 190 kDa to 310 kDa), high molecular weight chitosan (e.g., molecular weight range of 310 kDa to 375 kDa), and ultra-high molecular weight chitosan (e.g., molecular weight greater than 375 kDa).

[0047] Chitosan also carries a positive charge in acidic to neutral solutions, with the charge density depending on the pH and degree of deacetylation. The pka value of chitosan is typically between 6.1 and 7.0, depending on the degree of deacetylation. Therefore, although chitosan is essentially insoluble in distilled water, it is generally soluble in dilute acidic aqueous solutions (e.g., pH = 6.5 or lower).

[0048] In some embodiments, chitosan is in the form of an organic salt, including chitosan organic acid salts based on acetic acid (acetate) or citric acid (citrate).

[0049] In some embodiments, the organic polymeric hemostat comprises a soluble form of chitosan.

[0050] In some embodiments, the organic polymer hemostat comprises chitosan in particulate form. In some embodiments, the organic polymer hemostat in particulate form is freeze-dried.

[0051] In some embodiments, the particulate hemostat comprises a core comprising a chitosan salt and a shell comprising a polyanionic crosslinker, e.g., a polyphosphate crosslinker including a lithium, sodium, or potassium salt of tripolyphosphate, polymetaphosphate (e.g., trimetaphosphate and hexametaphosphate). Particles having the opposite structure (i.e., having a core comprising a tripolyphosphate and a shell comprising a chitosan salt) have been made. See et al., “Characterization of spraydried chitosan-TPP microparticles formed by two-and three-fluid nozzles”, Powder Technology 240 (2013) 31–40. However, to the best of the inventors’ knowledge, core-shell particles having the disclosed structure have not been prepared before. In addition, et al.’s particles involve microencapsulation applications using chitosan as an encapsulating agent.

[0052] In some embodiments, the concentration of the organic polymer hemostatic agent ranges from about 5% to about 50%, for example, in the range of 5% to 10% to 20% to 30% to 40% to 50%, relative to the total weight of the polysaccharide-based hydrogel at the point of application.

[0053] When provided in particulate (insoluble) form, the average particle size of the organic polymer hemostatic agent (measured by laser diffraction analysis or dynamic light scattering) ranges from 10 to 100,000 nm, for example, in the range of 10 nm to 25 nm to 50 nm to 100 nm to 250 nm to 500 nm to 750 nm to 1000 nm to 2,500 nm to 5,000 nm to 10,000 nm to 25,000 nm to 50,000 nm to 100,000 nm. In some embodiments, the average particle size ranges from 10 to 999 nm, for example, 100 to 300 nm.

[0054] When provided in particulate form, the organic polymer hemostat particles may include a shell that includes a polyanionic crosslinker, such as a polyanionic phosphate crosslinker.

[0055] When provided in particulate form, the organic polymer hemostat particles may also be provided with a coating, such as a thermosensitive coating or a pH sensitive coating.

[0056] Inorganic hemostats include calcium phosphate minerals such as hydroxyapatite and leucapatite. Hydroxyapatite has the formula Ca 5 (PO 4 ) 3 (OH), but is usually written as having the chemical formula Ca 10 (PO 4 ) 6 (OH) 2 . White apatite is reported to have the chemical formula Ca 9 (MgFe)(PO 4 ) 6 PO 3 OH.

[0057] In some embodiments, the concentration of the inorganic hemostatic agent ranges from about 5% to about 50% relative to the total weight of the polysaccharide-based hydrogel at the point of application, for example, in the range of 5% to 10% to 20% to 30% to 40% to 50%.

[0058] The average particle size of the inorganic hemostat ranges from 10 nm to 999 nm, for example, from 10 nm to 25 nm to 50 nm to 100 nm to 250 nm to 500 nm to 750 nm to 999 nm, typically from 100 nm to 300 nm. The particles of the inorganic hemostat may have a coating, such as a thermosensitive coating or a pH sensitive coating.

[0059] Small molecule organic hemostatic agents include amino acids, such as tranexamic acid, aminocaproic acid, 4-aminomethylbenzoic acid, and the like.

[0060] In some embodiments, the concentration of the small molecule organic hemostatic agent ranges from about 5% to about 50% relative to the total weight of the polysaccharide-based hydrogel at the point of application.

[0061] The small molecule organic hemostatic agent can be provided in a dissolved form or a particle form, including soluble and insoluble particle forms. When provided in a particle form, the average particle size of the small molecule organic hemostatic agent ranges from 10 to 999 nm, for example, ranging from 10 nm to 25 nm to 50 nm to 100 nm to 250 nm to 500 nm to 750 nm to 999 nm, typically 100 to 300 nm.

[0062] Macromolecular organic hemostatic agents include hemostatic proteins such as thrombin, fibrin and fibrinogen.

[0063] In some embodiments, the concentration of the macromolecular organic hemostatic agent ranges from about 5% to about 50% relative to the total weight of the polysaccharide-based hydrogel at the point of application, for example, in the range of 5% to 10% to 20% to 30% to 40% to 50%.

[0064] The macromolecular organic hemostatic agent can be provided in dissolved form or in particulate form. When provided in particulate form, the average particle size of the macromolecular organic hemostatic agent ranges from 10 to 999 nm, for example, ranging from 10 nm to 25 nm to 50 nm to 100 nm to 250 nm to 500 nm to 750 nm to 999 nm, typically 100 to 300 nm.

[0065] The composition of the present disclosure may further comprise other additives in addition to the above-mentioned polysaccharide, cross-linking agent and hemostatic agent.

[0066] In some embodiments, the composition may include one or more colorants. In some cases, the colorant may allow identification of the submucosal tissue plane when injected into the tissue, for example, to determine the amount of tissue to be removed and / or to assess the risk of perforation. Examples of colorants include, but are not limited to, brilliant blue (e.g., brilliant blue FCF, also known as FD&C blue 1), indigo carmine (also known as FD&C blue 2), indigo carmine lake, FD&C blue 1 lake, methylene blue (also known as methylene blue) or mixtures thereof, etc.

[0067] In some embodiments, the composition may include other suitable types of biocompatible agents. For example, the composition may include a formulation for appropriately adjusting the pH and / or tension of the composition. For example, the composition may include one or more stabilizers and / or preservatives.

[0068] As previously described, according to various aspects of the present disclosure, the compositions of the present disclosure can be used to form a polysaccharide-based hydrogel comprising a polysaccharide, a cross-linking agent, and a hemostatic agent at a point of application to a patient (e.g., a target site between tissue layers). When the polysaccharide-based hydrogel is used as a submucosal lifter, tissue excision and / or peeling can be performed after the hydrogel is injected and submucosal lift. Surgical excision of tissue can produce internal wounds and bleed easily. The hemostatic properties of the polysaccharide-based hydrogel promote hemostasis at the site of application, for example, as a physical coagulant or by eluting a hemostatic agent (e.g., eluting a small molecule active drug component, such as tranexamic acid or aminocaproic acid), or both.

[0069] In some embodiments, the polysaccharide, cross-linking agent, and hemostatic agent are provided in the form of a single injectable composition. In some embodiments, a first injectable co-composition comprising a polysaccharide and a cross-linking agent is co-administered with a second injectable co-composition comprising a hemostatic agent. Thus, in some embodiments, the cross-linked hydrogel is pre-loaded with a hemostatic agent and administered to the target site. In some embodiments, the cross-linked hydrogel is co-administered with a hemostatic agent.

[0070] As previously mentioned, the hemostatic agent can be in solid form (e.g., as particles) or in solution during administration. After administration, the hemostatic agent may change form under physiological conditions. For example, particles of the hemostatic agent may dissolve under physiological conditions, or a solution of the hemostatic agent may precipitate under physiological conditions.

[0071] Hemostatic agents can provide immediate and / or extended treatment at the site of tissue occlusion. For example, hemostatic agents can remain in place after surgery, either forming a complex with the hydrogel or acting as a hemostatic reservoir to allow the hemostatic agent to elute over a period of time after surgery, thereby providing an extended therapeutic effect. Although a portion of the cross-linked hydrogel is typically removed with the tissue, the remaining cross-linked hydrogel is slowly biodegraded over time and has the potential to remain in place throughout the healing phase or even after the healing period.

[0072] As previously stated, the present disclosure provides compositions and co-compositions for injection into a patient.

[0073] In use, the administered composition or administered co-composition (eg, hydrogel, solution, etc.) can be delivered to a target site of a patient via a suitable medical device (eg, a syringe or a fluid reservoir connected to an injection needle).

[0074] The composition and co-composition may have a viscosity suitable for injection from a selected medical device. In some embodiments, the composition or co-composition may be pseudoplastic. Pseudoplasticity generally refers to the property that the viscosity decreases when a shear force is applied. Thus, for example, the viscosity of the composition under static or low shear conditions (e.g., when stored in a container) may be higher than the viscosity under high shear conditions (e.g., when loaded into a needle and / or injected through a needle).

[0075] The compositions and co-compositions can be sterilized by various methods. For example, the compositions and co-compositions can be autoclaved within a reservoir (e.g., a syringe barrel) by heating the mixture to or to a temperature of about 121° C. Alternatively or additionally, the compositions and co-compositions can be sterilized by sterile filtration and / or by introduction of gamma or electron beam radiation into the reservoir.

[0076] The present invention also provides a medical device comprising the composition and co-composition described herein. The medical device can be used to inject the composition or co-composition into a patient's tissue, for example, to remove at least a portion of the tissue.

[0077] According to some aspects of the present disclosure, medical devices may include one or more reservoirs. Reservoirs may be used as containers for compositions and co-compositions described herein. Suitable reservoirs may include, for example, syringe barrels (e.g., syringe barrels compatible with manual or automatic injection systems), flexible bags (e.g., plastic bags) and other fluid containers configured for use with suitable injection needles. Exemplary materials suitable for reservoirs include, but are not limited to, cycloolefin copolymers, cycloolefin polymers, polypropylene, polycarbonate, polyvinyl chloride and glass.

[0078] The medical device herein may include one or more needles. In some examples, the reservoir of the medical device may be directly coupled to the needle, such as by a Luer connector or other suitable connection, or may be indirectly coupled to the needle by a flexible tube (e.g., a catheter). A non-limiting example of a needle coupled to the reservoir by a flexible tube includes the InterjectTM sclerotherapy needle of Boston Scientific. In some examples, the needle may be a hypodermic needle, which may range in size from 7 gauge (4.57 mm outer diameter (OD), 3.81 mm inner diameter (ID)) to 33 gauge (0.18 mm OD, 0.08 mm ID), for example, ranging in size from 16 gauge (1.65 mm OD, 1.19 mm ID) to 21 gauge (0.82 mm OD, 0.51 mm ID) to 22 gauge (0.72 mm OD, 0.41 mm ID) to 23 gauge (0.64 mm OD, 0.33 ID) to 24 gauge (0.57 mm OD, 0.31 mm ID), as well as other sizes. Exemplary materials for the needle include, but are not limited to, metals and metal alloys, such as stainless steel and nitinol, and polymers. The distal tip of the needle can be sharpened and can have a beveled shape. The proximal end of the needle can include a suitable fitting / adapter (e.g., a Luer adapter) for engaging with a syringe barrel or other reservoir. In some examples, the needle can include an elongated tube or catheter located between the needle tip and the proximal fitting / adapter.

[0079] Further disclosed herein is a method of removing at least a portion of tissue from a subject (e.g., a human patient). The method may include injecting a composition described herein into a tissue of a subject and removing at least a portion of the tissue from the patient.

[0080] Figure 1A An exemplary syringe 10 is shown that provides a reservoir for a composition or co-composition 15 as described above. The syringe 10 may include a barrel 12, a plunger 14, and one or more stoppers 16. The barrel 12 may include a Luer adapter (or other suitable adapter / connector), for example, at the distal end 18 of the barrel 12, for attachment to an injection needle 50 via a flexible conduit 29. The proximal end of the conduit 29 may include a suitable connection 20 for receiving the barrel 12. In other examples, the barrel 12 may be directly coupled to the injection needle 50. The syringe barrel 12 can be used as a reservoir, containing a composition or co-composition 15 for injection through the needle 50.

[0081] Figure 1B An exemplary syringe 30 for use with an automatic injection system 45 is shown. The syringe 30 may include Figure 1AAny features of the syringe 10 of the present invention, such as the barrel 32, the plunger 34, and the Luer adapter (or another suitable adapter / connector) located at the distal end 38 of the barrel 32. The composition or co-composition 15 as described above can be loaded into the barrel 32, and the syringe 30 can be inserted into the channel 47 of the injection system 45 to automatically control the amount of hydrogel injected. The distal end 38 of the syringe 30 can be connected to the injection needle (e.g., similar to Figure 1A In some aspects of the present disclosure, the plunger 34 may form part of the injection system 45, and the barrel 32 may be a separate component, such as a replaceable cartridge, to be connected to the injection system 45. For example, the composition or co-composition 15 may be prepared in the barrel 32 as a replaceable cartridge with a proximal attachment compatible with the plunger assembly of the injection system 45.

[0082] Figure 1C An exemplary reservoir 60 according to some aspects of the present disclosure is shown. The reservoir 60 can be provided by a flexible bag or bag, such as an IV bag. The composition or co-composition 15 described herein can be loaded into the reservoir 60. The reservoir 60 can be sterile and can include a plastic material (e.g., polyvinyl chloride (PVC) (e.g., with a plasticizer, such as bis (2-ethylhexyl) phthalate (DEHP))), or a non-PVC plastic material. The bag can include a Luer connector 63 for attachment to a catheter 69 and / or a needle (with any suitable gauge size, as described above) to inject the composition or co-composition 15 into the patient. The reservoir 60 can be compressible, for example, to allow the composition to be delivered through the catheter 69 and / or the needle by compressing the reservoir 60.

[0083] The amount of force required to move a composition or co-composition through the needle hole (often referred to as the "peak load" force) may depend on the viscosity of the composition or co-composition, the size of the needle (inner diameter, outer diameter, and / or length), and / or the material from which the needle is formed. For example, it may be necessary to apply a greater force to inject a composition or co-composition through a 33-gauge needle as compared to a 7-gauge needle. Other factors that may affect the amount of force required to inject the composition or co-composition may include the size (inner diameter, outer diameter, and / or length) of the catheter connecting the reservoir to the needle. A suitable peak load range for injection with one or two hands may be from about 5 lbf to about 25 lbf, such as from about 10 lbf to about 20 lbf, such as about 15 lbf. The load measured for a given hydrogel concentration may vary for different needles and flow rates. For situations where a higher peak load force is required, a needle having a peak load such as Figure 1B The shown machine driven plunger injection system may also be useful.

[0084] According to some aspects of the present disclosure, the size of the needle can be selected according to the viscosity and / or components of the composition or co-composition, and vice versa. In addition, the size (inner diameter, outer diameter and / or length) of the catheter body may affect the type and size of the force applied to the composition or co-composition during injection. These parameters can be considered according to the properties of the composition or co-composition and the needs of the patient. According to some aspects of the present disclosure, the size of the needle can be No. 23 or No. 25. In some cases, a larger size of No. 20, No. 21 or No. 22 can be used to inject the composition or co-composition.

[0085] Compositions or co-compositions as described herein can be used for various medical surgeries, including tissue excision and stripping surgeries of the gastrointestinal system, respiratory system and / or urogenital system. The tissue excised or stripped in such medical surgeries may include diseased or injured tissue, non-diseased tissue, or a combination thereof. Exemplary tissue excision surgeries include endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) as described above. In these surgeries, an endoscope is typically inserted into the patient's esophagus and advanced through the gastrointestinal system to reach a target site in the esophagus, stomach, or intestines. EMR is typically used to remove tissues less than 2 cm in diameter, such as biopsies or removal of injured or diseased tissues (e.g., cancerous lesions), while ESD is typically used to remove larger lesions.

[0086] In some aspects, compositions as described herein or co-compositions can be injected between two layers of tissue, for example, injected into the submucosal tissue between the upper mucosal layer and the lower muscularis propria at the target treatment site. Compositions or co-compositions can be injected into the submucosal space (submucosal layer) below the tissue portion, and the material injected subsequently can cause the mucosal tissue to be separated from the muscularis propria, thereby raising the mucosal tissue layer. Then suitable cutting devices (such as electrocautery cutting devices, such as knife, snare, scissors or tweezers) can be used to remove the tissue portion. In order to remove larger tissue portions (for example, by ESD), compositions or co-compositions can be injected under the tissue portion, wherein the hydrogel raises the upper layer of the tissue from the lower layer. Then cutting devices can be used to cut around the tissue portion and remove it. The composition or co-compositions can be injected into the submucosal layer to help remove the extra part of the tissue.

[0087] In various aspects, the hydrogel maintains the separation of tissue layers throughout the surgery. A portion of the hydrogel may be removed by excision surgery. However, at least a portion of the hydrogel will typically remain in place after surgery to contact one or more tissue layers, as discussed further below.

[0088] Figure 2A-2EAn exemplary resection procedure according to some aspects of the present disclosure is shown. For example, the procedure may be EMR or ESD as described above, or any other medical procedure suitable for resecting tissue. Figure 2A A cross-sectional view of two tissue portions or tissue layers 80, 82 is shown, which may be separated by an intermediate tissue layer 81 (e.g., an upper mucosal layer and a lower muscularis propria separated by an intermediate submucosal tissue layer). One or both of the tissue portions 80, 82 may include a tissue portion 85 to be removed. For example, the tissue portion 85 may include injured or diseased tissue, or may include tissue to be biopsied and subsequently analyzed. Figure 2A In the example shown, tissue portion 85 is located near the tissue surface, however, the devices and compositions disclosed herein can be used to remove tissue from inner tissue layers.

[0089] like Figure 2B As shown, an endoscope 100 defining one or more lumens (e.g., three lumens as shown) can be used to deliver the needle 70 to the treatment site. The needle 70 can have a hollow lumen and a sharp beveled tip 72 for piercing the tissue surface so that the needle tip 72 is located in the middle layer 81 between the upper tissue 80 and the lower tissue 82. The needle lumen can be connected to a fluid reservoir (e.g., a syringe or other reservoir containing the composition or co-composition prepared as described above). The composition or co-composition can be injected into the middle layer 81 between the tissue portions 80, 82 using a syringe to form a pad or vesicle of the polysaccharide-based hydrogel 90, such as Figure 2B Once the composition or combined co-composition is injected, the volume of the polysaccharide-based hydrogel 90 (also referred to herein as the polysaccharide-based hydrogel at the point of administration) may cause separation of the upper tissue 80 and the lower tissue 82, so that the tissue portion 85 can be raised from the underlying tissue. The tissue portion 85 can be cut and removed using an electrocautery snare 74 or other cutting device 74 (such as, for example, an electrocautery knife, scissors or forceps, and other suitable cutting devices), as shown. Figure 2C and 2D shown.

[0090] like Figure 2E As shown, once the tissue portion 85 is removed, a portion of the polysaccharide-based hydrogel 90 remains in place after surgery, in contact with one or more tissue layers 80, 81, 82. In this way, the polysaccharide-based hydrogel 90 can act as a barrier (i.e., a "band-aid") to protect the wound and / or reduce or prevent blood flow after tissue excision or peeling until the polysaccharide-based hydrogel biodisintegrates. In some embodiments, the polysaccharide-based hydrogel 90 can also act as a reservoir for hemostatic agents to allow the hemostatic agent to be eluted during surgery and / or for a period of time after surgery, thereby providing immediate and / or extended treatment options. Example 1 raw material:

[0091] Available from Boston Scientific Corporation, Marlborough, Massachusetts, USA. Gellan gum is available in low acyl CG-LA grades. Chitosan FD is provided in the form of , from CP Kelco US Inc., Atlanta, Georgia, USA. The salt is prepared as a solution of calcium chloride and sodium chloride in sterile water. Chitosan FD is freeze-dried chitosan, more specifically, electrosprayed chitosan (acetate) particles, which are cross-linked with tripolyphosphate (e.g., sodium tripolyphosphate) and then freeze-dried, and Chitosan FD can be prepared according to Example 1 of U.S. Patent Publication No. 2021 / 0322629.

[0092] Samples were ground and sieved to <50 μm. Hydroxyapatite nanopowder (<200 nm PSD, 97%) was provided by Aldrich (MilliporeSigma, St. Louis, MO, USA). Aminocaproic acid (ACA) (received as 6-aminocaproic acid) was provided by Merck & Co. Inc., Branchburg, NJ, USA. Tranexamic acid (TXA) was provided by Merck in pure powder form. Ninhydrin powder (spectrophotometric grade) was provided by Merck. Preformed gel preparation

[0093] Preformed hydrogels loaded with complexes: Commercially available The (polysaccharide-based) hydrogel was loaded into a small mixing vessel and stirred at 300 rpm. The composite (5% w / w chitosan FD (ground <50 μm) or 10% w / w chitosan FD (ground <50 μm) or 5% w / w hydroxyapatite (200 nm)) was added to the stirred hydrogel and mixed at room temperature for <10 minutes. Once mixing was complete, the syringe (10 ml) was back-loaded and then stored refrigerated.

[0094] Preformed hydrogel loaded with drug: Commercially available polysaccharide-based hydrogel was loaded into a small mixing vessel and stirred at 300 rpm. API drug powder (25% w / w aminocaproic acid or 15% w / w tranexamic acid) was added to the stirred hydrogel and mixed at room temperature for <10 minutes. Once mixing was complete, the syringe (10 ml) was back-loaded and then stored in the refrigerator. Pre-loaded gel preparation

[0095] Formed hydrogels loaded with composites (final composition <1.5% GGw / w): The gellan gum (polysaccharide) stock was hydrated (2 hours, +70°C) and then cooled to 40°C. Once cooled, the composites (5% w / w chitosan FD (ground <50 μm) or 10% w / w chitosan FD (ground <50 μm) or 5% w / w hydroxyapatite (200 nm)) were added with stirring, followed by the crosslinker salt solution (calcium chloride and sodium chloride). The mixture was stirred for an additional <10 minutes, then filled into syringes (3 ml or 10 ml) and stored refrigerated. Property Test

[0096] Injection force evaluation: Gel-loaded syringes were tested using an Instron tensile tester 5965 (Instron, Norwood, MA, USA) and selected needle gauges (18G or 19G) or InterjectTM administration catheters (Boston Scientific). Injection force tests were performed at a speed of 2.36 mm / s at a 20 mm stroke distance. The prototype was equipped with a 100 N dynamometer and compared to a commercial Benchmark tests were performed. Table 1 Injection force evaluation PSD: Particle Size Distribution

[0097] The results show that the composition containing 5% hydroxyapatite successfully achieved comparable maximum injection forces at <200nm. The 5% and 10% chitosan FD exceeded the 100N limit of the instrument. This observation leads to the conclusion that the particle size of the composite material is preferably around 200nm.

[0098] Kinetic drug release: The drug-loaded sample (1 g) was loaded into a 6-well transport plate containing 6 ml of D-PBS (Dulbecco's phosphate buffered saline) and stirred at 100 rpm (rotating incubator) at 37°C. At 0, 2, 4 and 24 hours, 500 μl aliquots of supernatant were extracted (the extracted supernatant was supplemented with 500 μl DPBS). 20 μl of supernatant was added to 100 μl aliquots of 2% w / w ninhydrin solution. The mixed solution was heated until a purple color appeared (+70°C, >10 minutes). The solution was cooled to room temperature and 500 μl of ethanol was added. 100 μl of the final purple solution was transferred to a 96-well UV transparent well plate and analyzed at 570 nm on a BioTek Epoch UV plate reader (Agilent Technologies, Santa Clara, CA, USA). Recovery results were determined based on comparative drug calibration curves.

[0099] Preparation of 2% Ninhydrin solution: 2% Ninhydrin powder is dissolved in 50:50 ethanol:0.05% glacial acetic acid.

[0100] Calibration curves were drawn at target concentrations of 60, 30, 15, 7.5 mg / ml drug (ACA or TXA) in D-PBS. 20 μl aliquots were added to 100 μl of 2% ninhydrin solution. The mixed solution was heated until purple appeared (+70°C, >10 minutes). The solution was cooled to room temperature and 500 μl of ethanol was added. 100 μl aliquots of the final purple solution were transferred to a 96UV transparent well plate and analyzed at 570 nm.

[0101] Kinetic drug release analysis showed that the average recovery of 6-aminocaproic acid in the D-PBS supernatant was less than 80% within 2 hours after administration (see Figure 3 ). This indicates that the gel loaded with the amino acid drug product was appropriate, applied as needed, and eluted immediately.

[0102] Kinetic drug release analysis showed that the average recovery of tranexamic acid in the D-PBS supernatant was less than 70% within 2 hours after administration (see Figure 4 ). This indicates that the gel loaded with yet another amino acid drug product was appropriate, applied as needed, and eluted immediately. Example 2

[0103] Chitosan FD (freeze-dried, electrosprayed particles of chitosan acetate cross-linked with tripolyphosphate) with an average particle size of ∼5000 nm was prepared by ball milling in a P7 planetary ball mill (e.g., Fritsch PULVER-ISETTE planetary ball mill, FRITSCH Milling and Sizing, Inc., Pittsboro, NC, USA). 80 mg of Chitosan FD and zirconium microbeads (1.4 mm, 20 g) were milled in hexane at 400 rpm for 10 min.

[0104] Spray-dried particles with a chitosan core coated with tripolyphosphate were prepared. The chitosan particles were prepared as follows: chitosan solution (ultra-high molecular weight chitosan dissolved in aqueous acetic acid) and aqueous tripolyphosphate solution were spray dried in a Buchi B-290 micro spray dryer (BUCHI Corporation, New Castle, DE, USA) with a three-fluid nozzle. The chitosan acetate aqueous solution was fed into the inner fluid nozzle and the tripolyphosphate aqueous solution was fed into the outer fluid nozzle to form a core / shell structure with a chitosan core and a tripolyphosphate shell (wherein the chitosan was cross-linked by tripolyphosphate to the extent that they mixed at the interface). The outlet temperature was set to a relatively low 49°C to reduce the risk of degradation. Figure 5 is a micrograph of core / shell particles produced by this process. Figure 6is a graph showing the particle size distribution, bulk density (%) versus particle size (μm) of a collection of particles produced according to the above process as measured by a Malvern Mastersizer (Malvern Instruments, Malvern, UK).

[0105] Will be commercially available The hydrogel was loaded into a small mixing vessel and stirred at 300 rpm. 5% w / w chitosan FD was added to the stirred hydrogel and mixed at room temperature for <10 minutes. Once mixing was complete, the syringe (10 ml) was back-loaded and then stored in the refrigerator.

[0106] The gel-loaded syringes were tested using an Instron tensile tester 5965 and a 23G InterjectTM administration catheter as described above. A 100 N dynamometer was fitted and the prototype was compared to a commercial Benchmark tests were performed. Table 2. Injection force evaluation

Claims

1. An injectable polysaccharide-based hydrogel comprising anionic polysaccharides, cationic crosslinking agents and hemostatic agents.

2. The injectable polysaccharide-based hydrogel according to claim 1, wherein the anionic polysaccharide contains glucuronic acid repeating units.

3. The injectable polysaccharide-based hydrogel according to claim 1, wherein the anionic polysaccharide comprises gellan gum.

4. The injectable polysaccharide-based hydrogel according to any one of claims 1 to 3, wherein the concentration of the anionic polysaccharide ranges from about 0.05% to about 1.0% relative to the total weight of the injectable polysaccharide-based hydrogel.

5. The injectable polysaccharide-based hydrogel according to any one of claims 1 to 4, wherein the cationic cross-linking agent comprises a salt containing a divalent metal cation.

6. The injectable polysaccharide-based hydrogel according to any one of claims 1 to 5, wherein the concentration of the cationic crosslinking agent ranges from about 0.01% to about 0.25% relative to the total weight of the injectable polysaccharide-based hydrogel.

7. The injectable polysaccharide-based hydrogel according to any one of claims 1 to 6, wherein the hemostatic agent is selected from the group consisting of organic polymer hemostatic agents, small molecule organic hemostatic agents, macromolecular organic hemostatic agents and inorganic hemostatic agents.

8. The injectable polysaccharide-based hydrogel according to any one of claims 1 to 7, wherein the hemostatic agent is in the form of particles with an average particle size of less than 50,000 nm.

9. The injectable polysaccharide-based hydrogel according to claim 8, wherein the hemostatic agent comprises a core comprising a chitosan salt and a shell comprising a polyanionic crosslinker.

10. The injectable polysaccharide-based hydrogel according to any one of claims 1 to 9, wherein the concentration of the hemostatic agent ranges from about 5% to about 50% relative to the total weight of the injectable polysaccharide-based hydrogel.

11. A medical device comprising a reservoir containing the injectable polysaccharide-based hydrogel according to any one of claims 1 to 10.

12. The medical device of claim 12, wherein the reservoir is a syringe barrel.

13. The medical device according to claim 13, wherein the medical device further comprises a needle through which the injectable polysaccharide-based hydrogel is injected.

14. Use of the medical device of claim 14 in a medical procedure for lifting an upper mucosal layer from an underlying layer.

15. A kit comprising, in suitable packaging material: a medical device according to any one of claims 11-13; and one or more items selected from (a) an endoscopic injection needle, (b) a tissue resection device, (c) a tissue retrieval device, and (d) an endoscope.

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