Bottle brush polymers and multi-arm polymers for medical applications

Abstract

A reactive bottle brush polymer for medical applications is described comprising a polymer backbone and a plurality of polymer side chains attached to the polymer backbone, at least a portion of the side chains each comprising a hydrophilic polymer segment covalently attached to the polymer backbone, and a reactive moiety covalently attached to the hydrophilic polymer segment at a side chain end opposite the polymer backbone. Also described are reactive multi-arm polymers for medical applications comprising three or more polymer arms, each polymer arm comprising a hydrophilic polymer segment comprising one or more polar aprotic vinyl monomer residues and a reactive moiety covalently attached to the hydrophilic polymer segment. Also described is a reactive polysaccharide for medical applications comprising a polysaccharide backbone comprising a free carboxyl group and a cyclic imide ester group covalently linked along the length of the polysaccharide backbone.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 509,483, filed June 21, 2023, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to reactive multi-arm polymers, reactive bottle-brush polymers and reactive polysaccharide polymers, crosslinked hydrogels formed from such polymers, and crosslinkable systems for forming such hydrogels. The reactive polymers, hydrogels, and crosslinkable systems for forming them can be used in, for example, various medical applications. Background Technology

[0004] Bioabsorbable hydrogels with a rapid in vivo cross-linking reaction rate (trade name SpaceOAR®) have become an important biomaterial, achieving clinical success in creating space between the prostate and rectum, significantly improving patient safety during cancer treatment. Further improvements based on this application involve functionalizing some 8-arm PEG branches with 2,3,5-triiodobenzamide (TIB) groups, replacing partially activated ester end groups, namely succinimidyl glutarate (SG), to provide the hydrogel itself with inherent radiopaqueness for CT visibility. This hydrogel, traded as SpaceOAR Vue®, represents the next generation of SpaceOAR® for prostate medical applications. Summary of the Invention

[0005] This disclosure provides alternative methods to the above-described methods.

[0006] In some aspects, this disclosure provides a reactive bottle-brush-like polymer comprising a polymer backbone and a plurality of polymer side chains connected to the polymer backbone, at least a portion of each side chain comprising a hydrophilic polymer segment covalently connected to the polymer backbone and a reactive portion covalently connected to the hydrophilic polymer segment at the end of the side chain opposite to the polymer backbone.

[0007] In some embodiments applicable to the above aspects, the reactive portion comprises an electrophilic group or an alkenyl-containing group.

[0008] In some embodiments applicable to the above aspects, the reactive portion comprises a cyclic imide ester group, an imidazole ester group, an imidazole carboxylic ester group, a benzotriazole ester group, an acryloyl group, or a methacryloyl group.

[0009] In some embodiments suitable for the above aspects and embodiments, the hydrophilic polymer segment is selected from a poly(ethylene oxide)-containing segment, a poly(amino acid)-containing segment, a poly(oxazoline)-containing segment, or a hydrophilic polymer segment containing one or more residues of a polar aprotic vinyl monomer.

[0010] In some embodiments suitable for the above aspects and embodiments, the hydrophilic polymer segment is an iodine-containing hydrophilic polymer segment.

[0011] In some embodiments suitable for the above aspects and embodiments, the reactive bottlebrush polymer further comprises a cyclic anhydride residue located between the hydrophilic polymer segment and the reactive moiety. In some of these embodiments, the cyclic anhydride residue is an iodine-containing cyclic anhydride residue, and / or the cyclic anhydride residue is selected from a residue of an iodine-containing or non-iodine-containing glutaric anhydride compound, a residue of an iodine-containing or non-iodine-containing succinic anhydride compound, a residue of an iodine-containing or non-iodine-containing malonic anhydride compound, a residue of an iodine-containing or non-iodine-containing adipic anhydride compound, and a residue of an iodine-containing or non-iodine-containing diglycolic anhydride compound.

[0012] In some aspects, the present disclosure provides a crosslinking reaction of a crosslinking hydrogel composition comprising (a) a polyamino compound and (b) a reactive bottlebrush polymer according to any of the above aspects and embodiments.

[0013] In some embodiments, the present disclosure provides a system for forming a hydrogel composition comprising (a) a polyamino compound and (b) a bottlebrush polymer according to any of the above aspects and embodiments. In some embodiments, the system comprises a first composition comprising the polyamino compound, a second composition comprising the reactive bottlebrush polymer, and, optionally, a promoter composition.

[0014] In some embodiments, the present disclosure provides a method of treatment comprising administering to a subject a mixture comprising (a) a polyamino compound and (b) a reactive bottlebrush polymer according to any of the above aspects and embodiments, under conditions such that the polyamino compound and the reactive bottlebrush polymer crosslink upon administration.

[0015] In some embodiments, the present disclosure provides a method of treatment comprising administering to a subject’s body a reactive bottlebrush polymer according to any of the above aspects and embodiments, under conditions such that the reactive bottlebrush polymer reacts with a naturally occurring amine within or on the subject’s body upon administration.

[0016] In other aspects, the present disclosure relates to a reactive multi-arm polymer comprising three or more polymer arms, each polymer arm comprising a hydrophilic polymer segment containing one or more residues of a polar aprotic vinyl monomer and a reactive moiety covalently attached to the hydrophilic polymer segment.

[0017] In some embodiments suitable for the above aspects, the reactive moiety comprises an electrophilic group or an alkenyl-containing group.

[0018] In some embodiments suitable for the above aspects, the reactive moiety comprises a cyclic imide ester group, an imidazole ester group, an imidazole carboxylate group, a benzotriazole ester group, an acryloyl group, or a methacryloyl group.

[0019] In some embodiments suitable for the above aspects and embodiments, the hydrophilic polymer segment is selected from a poly(ethylene oxide)-containing segment, a poly(amino acid)-containing segment, a poly(oxazoline)-containing segment, or a hydrophilic polymer segment containing one or more residues of a polar aprotic vinylic monomer.

[0020] In some embodiments suitable for the above aspects and embodiments, the hydrophilic polymer segment is an iodine-containing hydrophilic polymer segment.

[0021] In some embodiments suitable for the above aspects and embodiments, the reactive bottlebrush polymer further comprises a cyclic anhydride residue located between the hydrophilic polymer segment and the reactive moiety. In some of these embodiments, the cyclic anhydride residue is an iodine-containing cyclic anhydride residue, and / or the cyclic anhydride residue is selected from a residue of an iodine-containing or non-iodine-containing glutaric anhydride compound, a residue of an iodine-containing or non-iodine-containing succinic anhydride compound, a residue of an iodine-containing or non-iodine-containing malonic anhydride compound, a residue of an iodine-containing or non-iodine-containing adipic anhydride compound, and a residue of an iodine-containing or non-iodine-containing diglycolic anhydride compound.

[0022] In some aspects, the present disclosure provides a crosslinked hydrogel composition comprising (a) a polyamino compound and (b) a crosslinking reaction of a reactive multi-armed polymer according to any of the above aspects and embodiments.

[0023] In some embodiments, the present disclosure provides a system for forming a hydrogel composition comprising (a) a polyamino compound and (b) a multi-armed polymer according to any of the above aspects and embodiments. In some of these embodiments, the system comprises a first composition comprising the polyamino compound, a second composition comprising the reactive multi-armed polymer, and optionally a promoter composition.

[0024] In some embodiments, the present disclosure provides a method of treatment comprising administering to a subject a mixture comprising (a) a polyamino compound and (b) a reactive multi-armed polymer according to any of the above aspects and embodiments, under conditions such that the polyamino compound and the reactive multi-armed polymer crosslink upon administration.

[0025] In some embodiments, the present disclosure provides a method of treatment comprising administering to the body of a subject a reactive multi-arm polymer according to any of the above aspects and embodiments under conditions such that the reactive multi-arm polymer reacts with naturally occurring amines within or on the body of the subject after administration.

[0026] In other aspects, the present disclosure relates to a reactive multi-saccharide comprising a multi-saccharide backbone comprising covalently linked free carboxyl groups and cyclic imide ester groups along the length of the multi-saccharide backbone.

[0027] In some embodiments, the cyclic imide ester groups are selected from the group consisting of succinimidyl ester groups, maleimidyl ester groups, glutarimidyl ester groups, phthalimidyl ester groups, and bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid imidate groups.

[0028] In some embodiments suitable for the above aspects and embodiments, the multi-saccharide backbone is formed from a multi-saccharide comprising one or more uronic acid species.

[0029] In some embodiments suitable for the above aspects and embodiments, the multi-saccharide backbone is formed from hyaluronic acid.

[0030] In some embodiments, the present disclosure provides a crosslinked hydrogel composition comprising (a) a polyamino compound and (b) a crosslinking reaction of a reactive multi-saccharide according to any of the above aspects and embodiments.

[0031] In some embodiments, the present disclosure provides a system for forming a hydrogel composition comprising (a) a polyamino compound and (b) a reactive multi-saccharide according to any of the above aspects and embodiments. In some of these embodiments, the system comprises a first composition comprising the polyamino compound, a second composition comprising the reactive multi-saccharide, and optionally a promoter composition.

[0032] In some embodiments, the present disclosure provides a method of treatment comprising administering to a subject a mixture comprising (a) a polyamino compound and (b) a reactive multi-saccharide according to any of the above aspects and embodiments under conditions such that the polyamino compound and the reactive multi-saccharide crosslink after administration.

[0033] In some embodiments, the present disclosure provides a method of treatment comprising administering to the body of a subject a reactive multi-saccharide according to any of the above aspects and embodiments under conditions such that the reactive multi-saccharide reacts with naturally occurring amines within or on the body of the subject after administration.

[0034] Potential benefits associated with the present disclosure include one or more of the following: increased crosslinking density, in vivo persistence is achieved, and in some cases, radiocontrast is maintained or enhanced.

[0035] The above and other aspects, implementations, features and benefits of this disclosure will become apparent from the following detailed description. Attached Figure Description

[0036] Figure 1 A method for forming a reactive poly(ethylene oxide) bottle brush polymer according to an embodiment of the present disclosure is illustrated schematically.

[0037] Figure 2 A method for forming a reactive poly(amino acid) bottle brush polymer according to an embodiment of the present disclosure is illustrated schematically.

[0038] Figure 3 A method for forming a reactive polyoxazoline bottle brush polymer according to an embodiment of the present disclosure is illustrated schematically.

[0039] Figure 4 A method for forming a reactive hyaluronic acid polymer according to an embodiment of the present disclosure is illustrated schematically.

[0040] Figure 5 A method for forming a multifunctional RAFT reagent according to an embodiment of the present disclosure is illustrated schematically.

[0041] Figure 6 A method for forming a multifunctional RAFT reagent according to another embodiment of this disclosure is illustrated schematically.

[0042] Figure 7 The process of ammonolysis, thiol-Michael addition, and succinimide glutarate capping is schematically illustrated in various embodiments of this disclosure.

[0043] Figure 8 A delivery device according to an embodiment of the present disclosure is shown.

[0044] Figure 9 A delivery device according to another embodiment of this disclosure is shown. Detailed Implementation

[0045] In all respects, this disclosure relates to reactive polymers, including reactive bottle-brush polymers and reactive multi-arm polymers.

[0046] The reactive bottlebrush polymers according to the present disclosure include a polymer comprising a plurality of polymer side chains attached to a polymer backbone, at least a portion of the side chains having a reactive moiety covalently attached to a terminal end of the side chain opposite the polymer backbone. In some embodiments, at least a portion of the polymer side chains comprise a hydrophilic polymer segment covalently attached to a linear polymer backbone, a cyclic anhydride residue covalently attached to the hydrophilic polymer segment, and a reactive moiety covalently attached to the cyclic anhydride residue.

[0047] In particular embodiments, the reactive bottlebrush polymers comprise a plurality of polymer side chains attached to a linear polymer backbone, each polymer side chain comprising: a hydrophilic polymer segment having a first end and a second end, the first end of the hydrophilic polymer segment covalently attached to the linear polymer backbone; a cyclic anhydride residue having a first end and a second end, the first end of the cyclic anhydride residue covalently attached to the second end of the hydrophilic polymer segment; and a reactive moiety covalently attached to the second end of the cyclic anhydride residue.

[0048] The reactive bottlebrush polymers according to the present disclosure include a polymer having 3 to 100 side chains, for example, 3 to 4 to 5 to 6 to 7 to 8 to 10 to 12 to 15 to 20 to 25 to 50 to 75 to 100 side chains in any range of the foregoing (in other words, having a number of side chains ranging between any two of the foregoing values).

[0049] The hydrophilic polymer segment of the side chain can be selected from a variety of synthetic, natural, or synthetic-natural hybrid hydrophilic polymer segments. Examples of hydrophilic polymer segments include those formed from one or more hydrophilic monomers selected from alkylene oxides (e.g., ethylene oxide, propylene oxide, tetramethylene alkylene oxide, etc.), polar aprotic vinyl monomers (e.g., N-vinylpyrrolidone, acrylamide, N-methyl acrylamide, dimethyl acrylamide, N-vinylimidazole, 4-vinylimidazole, sodium 4-vinylbenzenesulfonate, etc.), oxazoline monomers (e.g., oxazoline and 2-alkyl-2-oxazolines, such as 2-(Ci-C6alkyl)-2-oxazolines, including various isomers, such as 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-n-propyl-2-oxazoline, 2-iso-propyl-2-oxazoline, 2-n-butyl-2-oxazoline, 2-iso-butyl-2-oxazoline, 2-hexyl-2-oxazoline, etc.), 2-phenyl-2-oxazoline, N-isopropyl acrylamide, amino acids, and sugars. In some embodiments, iodine-substituted or bromine-substituted counterparts of the foregoing monomers can be used to provide a final polymer having radio-opacity.

[0050] The hydrophilic polymer segment can be selected, for example, from the following polymer segments: polyether segments, including (polyalkylene oxide) segments, such as poly(ethylene oxide) (PEO) (also known as polyethylene glycol or PEG) segments, poly(propylene oxide) segments, poly(ethylene oxide-co-propylene oxide) segments, polymeric segments formed from one or more polar aprotic vinyl monomers (including poly(N-vinylpyrrolidone) segments, poly(acrylamide) segments, poly(dimethylacrylamide) segments, poly(N-vinylimidazole) segments, poly(4-vinylimidazole) segments, and poly(4-vinylbenzenesulfonic acid sodium salt) segments, etc.), polyoxazoline segments, including poly(2-Ci-C6-alkyl-2-oxazoline) segments, such as poly(2-methyl-2-oxazoline) segments, poly(2-ethyl-2-oxazoline) segments, poly(2-propyl-2-oxazoline) segments, poly(2-isopropyl-2-oxazoline) segments, and poly(2-n-butyl-2-oxazoline) segments, poly(2-phenyl-2-oxazoline) segments, poly(N-isopropylacrylamide) segments, protein segments, or polysaccharide segments. Polysaccharide segments include segments containing one or more uronic acid species, such as galacturonic acid, glucuronic acid, and / or iduronic acid, specific examples of polysaccharide segments include alginic acid, hyaluronic acid, pectin, agar gum, carrageenan, gellan gum, gum arabic, guar gum, xanthan gum, and carboxymethylcellulose moieties. The polymer segments used in the bottlebrush polymers and multiarm polymers of the present disclosure typically contain from 10 to 1000 monomeric units or more. In some embodiments, iodine-substituted or bromine-substituted counterparts of the foregoing polymer segments can be used to provide the final polymers with radio-opacity.

[0051] As previously described, in the reactive bottlebrush polymers of the present invention, the side chains comprising the hydrophilic polymer segment extend from the polymer backbone (typically a linear polymer backbone).

[0052] In some embodiments, the side chain precursor molecules in the form of macromonomers (or macromers) comprising the hydrophilic polymer segment and terminal polymerizable groups are first formed. Subsequently, the terminal polymerizable groups of the macromonomers are polymerized, optionally in the presence of one or more additional monomers, to form the precursor bottlebrush polymer having a linear polymer backbone and side chains comprising the hydrophilic polymer segment extending from the linear polymer backbone.

[0053] In some embodiments, the side chains comprising the hydrophilic polymer segment are polymerized from an initiator site along the length of the linear precursor polymer backbone, thereby forming the precursor bottlebrush polymer having a linear polymer backbone and side chains comprising the hydrophilic polymer segment extending from the linear polymer backbone.

[0054] The terminal end of at least a portion of the side chains of the precursor bottlebrush polymer has a reactive moiety. In some embodiments, the reactive moiety comprises an electrophile. The electrophile can be selected from, for example, cyclic imide ester groups, such as succinimide ester groups, maleimide ester groups, glutarimide ester groups, phthalimide ester groups, bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid imide ester groups, imidazole ester groups, imidazole carboxylate groups, and benzotriazole ester groups, among other possibilities. In other embodiments, the reactive moiety comprises an alkenyl-containing group, such as a vinyl group, a propenoyl group, or a methacryloyl group.

[0055] In some embodiments, a hydrolysable ester group is disposed between the reactive moiety and the hydrophilic polymer segment.

[0056] For example, the side chains of the bottlebrush polymer can comprise a hydrophilic polymer segment linked to the polymer backbone, a cyclic anhydride residue covalently linked to the hydrophilic polymer segment, and a reactive moiety covalently linked to the cyclic anhydride residue. In more specific embodiments, the side chains of the bottlebrush polymer can comprise: a hydrophilic polymer segment having a first terminal end and a second terminal end, the first terminal end of the hydrophilic polymer segment covalently linked to the polymer backbone; a cyclic anhydride residue having a first terminal end and a second terminal end, the first terminal end of the cyclic residue covalently linked to the second terminal end of the hydrophilic polymer segment; and a reactive moiety covalently linked to the second terminal end of the cyclic anhydride residue.

[0057] Examples of cyclic anhydride residues include glutaric anhydride residues, succinic anhydride residues, malonic anhydride residues, adipic anhydride residues, and diglycolic anhydride residues, among others.

[0058] In some embodiments, the cyclic anhydride residue is a residue of an iodine-containing cyclic anhydride. Examples of iodine-containing cyclic anhydrides include cyclic anhydrides in which at least one ring carbon of the cyclic anhydride compound is substituted with iodine alone or an iodinated moiety. Examples include cyclic anhydride compounds in which at least one ring carbon is substituted with an iodinated moiety comprising an iodinated aromatic group. Examples of iodinated aromatic groups include iodine-substituted monocyclic aromatic groups and iodine-substituted polycyclic aromatic groups, such as iodinated phenyl groups, iodinated naphthyl groups, iodinated anthryl groups, iodinated phenanthryl groups, or iodinated tetraphenyl groups. The iodinated aromatic group can be substituted with one, two, three, four, five, six, or more iodine atoms. In various embodiments, the aromatic group can be further substituted with one or more hydrophilic groups, such as one, two, three, four, five, six, or more hydrophilic groups. The hydrophilic group can be a hydroxyl-containing group, which can be selected from, for example, hydroxyl groups and hydroxyalkyl groups (e.g., hydroxyalkyl groups containing one carbon, two carbons, three carbons, four carbons, etc.). The iodinated aromatic group can be directly linked to the ring carbon, or can be linked to the ring carbon through any suitable linking moiety, which can be selected from, for example, alkyl groups, ether groups, ester groups, amide groups, amine groups, or carbonate groups, among others.

[0059] Specific examples of iodinated aromatic groups include those comprising one or more monocyclic or polycyclic aromatic structures, which are substituted with (a) one or more iodine groups (e.g., one, two, four, five, six, or more iodine atoms) and (b) optionally one or more hydroxyl-containing groups independently selected from one or more hydroxyl groups and / or one or more C1-C4-hydroxyalkyl groups (e.g., C1-C4-mono-hydroxyalkyl, C1-C4-di-hydroxyalkyl, C1-C4-tri-hydroxyalkyl, C1-C4-tetra-hydroxyalkyl), and the like, where the C1-C4-hydroxyalkyl groups can be attached directly or through any suitable linking moiety to the monocyclic or polycyclic aromatic structure, which linking moiety can be selected from, for example, an alkyl, ether, ester, amide, amine, or carbonate group, and the like.

[0060] Several specific examples of iodine-containing cycloate anhydrides for use in the present disclosure include the following iodine-containing glutaric anhydride compounds: 4-(2,3,5-triiodophenyl)tetrahydropyran-2,6-dione, CAS # 2357909-35-2, , 4-(2-iodophenyl)tetrahydropyran-2,6-dione, CAS # 2354202-92-7, , 4-(3-iodophenyl)tetrahydropyran-2,6-dione, CAS # 2353621-23-3, , 4-(4-iodophenyl)tetrahydropyran-2,6-dione, CAS # 2354237-72-0, , 4-((4-iodophenyl)methyl)tetrahydropyran-2,6-dione, CAS # 2354625-91-3, , 4-((4-iodophenyl)methyl)tetrahydropyran-2,6-dione, CAS # 2354625-91-3, , 3-(2-iodophenyl)tetrahydrofuran-2,5-dione, CAS # 887131-98-8, , 3-(3-iodophenyl)tetrahydrofuran-2,5-dione, CAS # 2353486-41-4, , 3-(4-iodophenyl)tetrahydrofuran-2,5-dione, CAS # 2354046-55-0, , 3-(2-iodophenyl)tetrahydrofuran-2,5-dione, CAS # 2353486-41-4, , 3-(2-iodophenyl)tetrahydrofuran-2,5-dione, CAS # 2353486-41-4, , and the like.

[0061] The above non-iodinated and iodinated cyclic anhydrides, etc., can be reacted with a precursor bottlebrush polymer comprising a linear polymer backbone and a side chain comprising a hydroxyl-terminated hydrophilic polymer segment extending from the linear polymer backbone under ring-opening conditions to form a non-iodinated or iodinated carboxylic acid-terminated precursor bottlebrush polymer comprising a side chain comprising a carboxylic acid end group attached to the hydrophilic polymer segment by a hydrolysable ester group.

[0062] The reactive moiety can then be attached to the non-iodinated or iodinated carboxylic acid-terminated precursor bottlebrush polymer.

[0063] For example, an electrophilic moiety (e.g., a cyclic imide ester group, an imidazole ester group, an imidazole carboxylate group, or a benzotriazole ester group) can be attached to the non-iodinated or iodinated carboxylic acid-terminated precursor bottlebrush polymer.

[0064] In particular embodiments, an N-hydroxyl cyclic imide compound (e.g., N-hydroxysuccinimide (NHS), N-hydroxymaleimide, N-hydroxeglutarimide, N-hydroxyphthalimide, N-hydroxybicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid imide (HONB) etc.) can be reacted with the non-iodinated or iodinated carboxylic acid-terminated precursor bottlebrush polymer in the presence of a suitable coupling agent (e.g., a carbodiimide coupling agent such as N,N’-dicyclohexylcarbodiimide (DCC), 1-ethyl-3-(3-dimethylpropyl)carbodiimide (EDC), N-hydroxybenzotriazole (HOBt), BOP reagent, and / or other coupling agents) to form a non-iodinated or iodinated reactive cyclic imide ester group (e.g., a non-iodinated or iodinated succinimide ester group, a non-iodinated or iodinated maleimide ester group, a non-iodinated or iodinated glutarimide ester group, a non-iodinated or iodinated phthalimide ester group, or a non-iodinated or iodinated bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid imide ester group, etc.) attached to the hydrophilic polymer segment by a hydrolysable ester group. In this way, a number of non-iodinated or iodinated reactive diester groups can be formed.

[0065] For example, in the specific case of N-hydroxysuccinimide as the N-hydroxyl cyclic imide compound, exemplary reactive end groups include non-iodinated or iodinated succinimidyl propiolate groups, non-iodinated or iodinated succinimidyl glutarate groups, non-iodinated or iodinated succinimidyl succinate groups, non-iodinated or iodinated succinimidyl adipate groups, and non-iodinated or iodinated succinimidyl diglycolate groups, among others. In the specific case of HONB as the N-hydroxyl cyclic imide compound, exemplary reactive end groups include non-iodinated or iodinated bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid imidate propiolate groups, non-iodinated or iodinated bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid imidate glutarate groups, non-iodinated or iodinated bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid imidate succinate groups, non-iodinated or iodinated bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid imidate adipate groups, or non-iodinated or iodinated bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid imidate diglycolate groups, among others. For example, in the specific case of N-hydroxymaleimide as the N-hydroxyl cyclic imide compound, exemplary reactive end groups include non-iodinated or iodinated maleimidyl propiolate groups, non-iodinated or iodinated maleimidyl glutarate groups, non-iodinated or iodinated maleimidyl succinate groups, non-iodinated or iodinated maleimidyl adipate groups, and non-iodinated or iodinated maleimidyl diglycolate groups, among others. In the specific case of N-hydroxypimelimide as the N-hydroxyl cyclic imide compound, exemplary reactive end groups include non-iodinated or iodinated pimelimideyl propiolate groups, non-iodinated or iodinated pimelimideyl glutarate groups, non-iodinated or iodinated pimelimideyl succinate groups, non-iodinated or iodinated pimelimideyl adipate groups, and non-iodinated or iodinated pimelimideyl diglycolate groups, among others. In the specific case of N-hydroxyphthalimide as the N-hydroxyl cyclic imide compound, exemplary reactive end groups include non-iodinated or iodinated phthalimidyl propiolate groups, non-iodinated or iodinated phthalimidyl glutarate groups, non-iodinated or iodinated phthalimidyl succinate groups, non-iodinated or iodinated phthalimidyl adipate groups, and non-iodinated or iodinated phthalimidyl diglycolate groups, among others.

[0066] As another example, an alkenyl-containing group (e.g., vinyl, acryloyl, or methacryloyl) can be attached to a non-iodinated or iodinated carboxylic acid-terminated precursor bottlebrush polymer. The addition of these functional groups can be accomplished by reaction of the end group (amine or alcohol) with an acid chloride (e.g., methacryloyl chloride) or an anhydride (e.g., acrylic anhydride).

[0067] Various specific embodiments will now be described in connection with the drawings. Figure 1A method of forming a reactive bottlebrush polymer comprising a plurality of side chains comprising a polyalkylene oxide (specifically, polyethylene oxide) segment covalently linked to a polyalkylene polymer backbone (specifically, a polyethylene backbone) is shown. Each side chain further comprises a reactive end moiety (specifically, a reactive end moiety comprising a succinimidyl ester group, more specifically, a succinimidyl glutarate group) covalently linked to the polyalkylene oxide segment via a hydrolysable ester. In the illustrated embodiment, an acrylate or alkyl acrylate-terminated PEG macromonomer is polymerized via reversible addition-fragmentation chain transfer polymerization (RAFT polymerization) to form a reactive bottlebrush polymer precursor. RAFT polymerization is a living radical polymerization technique. RAFT utilizes a chain transfer agent (a RAFT agent) to regulate polymerization through a reversible chain transfer process. Examples of RAFT agents include, for example, dithioesters, xanthates, trithiocarbonates, dithioamidocarbonates, and dithiophosphonic acid esters.

[0068] In Figure 1 the specific example shown, an acrylate or C1-C4-alkyl acrylate-terminated PEG macromonomer 110 (where R1 is -H or -C1-C4-alkyl, n is 3 to 500) is subjected to RAFT polymerization in the presence of a trithiocarbonate RAFT initiator 112, where R is an alkyl, aryl, or alicyclic functional group, to form a first precursor bottlebrush polymer having a linear acrylate or C1-C4-alkyl acrylate polymer backbone and side chains comprising hydrophilic polyethylene oxide segments extending from the linear polymer backbone, where the polyethylene oxide segments comprise terminal hydroxyl groups. The hydroxyl-terminated first precursor bottlebrush polymer is then reacted with glutaric anhydride via ring opening to yield a second precursor bottlebrush polymer having a linear acrylate or C1-C4-alkyl acrylate polymer backbone and side chains comprising glutarate-terminated polyethylene oxide segments extending from the linear polymer backbone. The glutarate-terminated second precursor bottlebrush polymer is then reacted with N-hydroxysuccinimide in the presence of a coupling agent to form a bottlebrush polymer 118 having a linear acrylate or C1-C4-alkyl acrylate polymer backbone and side chains comprising succinimidyl-glutarate-terminated polyethylene oxide segments extending from the linear polymer backbone. Figure 1 In

[0069] While an acrylate or C1-C4-alkyl acrylate-terminated PEG macromonomer is shown in Figure 1 , acrylate or C1-C4-alkyl acrylate-terminated macromonomers containing hydrophilic polymer segments other than PEG segments can also be envisioned.

[0070] Figure 2Methods of forming reactive bottlebrush polymers comprising a plurality of side chains comprising polyamide segments (specifically, polyamino acid segments) attached to a polymer backbone (specifically, a polyacrylate, polymethacrylate, or polynorbornene backbone) are described. The side chains further comprise a reactive end moiety covalently attached to the side chain by a hydrolysable ester (specifically, a reactive end moiety comprising a succinimidyl ester group, more specifically, a succinimidyl glutarate group).

[0071] In Figure 2 Methods, the poly(amino acid) macromonomer is first formed, followed by a suitable polymerization step. The poly(alpha-amino acid) macromonomer can be formed, for example, by first performing ring-opening polymerization of a cyclic monomer such as an (alpha-amino acid N-carboxyanhydride (NCA) monomer), which can be initiated by an amine, amine derivative, or organosilicon compound (such as hexamethyldisilazane (HMDS), N-trimethylsilylamine, or bis(trimethylsilyl)amine). In Figure 2 In

[0072] The polymerization step is followed by deprotection of the benzyl groups with iodotrimethylsilane (TMSI) to yield an amine-terminated copolymer 214, where n is an integer and can independently range, for example, from 2 to 500, among other possibilities. The amine-terminated copolymer 214 is then provided with polymerizable end groups, for example, by reaction with acryloyl chloride or methacryloyl chloride, or by reaction with norbornene bound to an acyl chloride, and ring-opening metathesis polymerization (ROMP) in the presence of an amine buffer to absorb residual generated hydrochloric acid. The resulting macromonomer 218 is then polymerized, for example, by RAFT or ROMP, to form a first precursor bottlebrush polymer having a linear acrylate or methacrylate polymer backbone or a linear polynorbornene backbone and side chains comprising poly(amino acid) segments extending from the linear polymer backbone, the poly(amino acid) segments comprising terminal amino groups. The amino-terminated first precursor bottlebrush polymer is then reacted with glutaric anhydride by amide coupling reaction to yield a second precursor bottlebrush polymer having a linear polyacrylate, polymethacrylate, or polynorbornene backbone and side chains comprising glutaric acid-terminated poly(amino acid) segments extending from the linear polymer backbone. The glutaric acid-terminated second precursor bottlebrush polymer is then reacted with N-hydroxysuccinimide in the presence of a coupling agent to form a bottlebrush polymer 220 having a linear acrylate, polymethacrylate, or polynorbornene backbone and side chains comprising succinimidyl-glutaric acid-terminated poly(amino acid) segments extending from the linear polymer backbone.

[0073] Figure 3 Methods of forming reactive bottlebrush polymers comprising a plurality of side chains comprising polyoxazoline segments linked to a polymer backbone, specifically a polyacrylate, polymethacrylate, or polynorbornene backbone, wherein each side chain has a reactive end moiety covalently linked to the side chain through a hydrolysable ester group, specifically an end moiety comprising a succinimidyl ester group, more specifically a succinimidyl glutarate ester group, are described.

[0074] In Figure 3In the specific embodiment shown, a polyoxazoline macromonomer is first formed, followed by a suitable polymerization step. For example, a polyoxazoline macromonomer can be formed by first polymerizing an oxazoline monomer 310, where R is selected from methyl, ethyl, n-propyl, i-propyl, phenyl, or triiodophenyl, among others, in the presence of a suitable initiator, such as a p-toluenesulfonate compound (e.g., methyl p-toluenesulfonate (MeOT)) or a triflate compound (e.g., methyl triflate (MeOTf)) or a t-butyldiphenylsilyl-protected 12-hydroxydodecyl triflate compound 312. The resulting transient cationic-terminated polymer is then end-capped and trapped with a carboxylic acid. For example, the resulting polymer can be reacted with acrylic acid, methacrylic acid, or 5-norbornene carboxylic acid in a cationic trap to form a (meth)acrylate-terminated polymer or a norbornene-terminated macromonomer, followed by deprotection of the t-butyldiphenylsilyl-protected hydroxyl group by a fluoride source, such as t- butylaminofluoride [TBAF]. The resulting methacrylate-terminated macromonomer 318, acrylate-terminated macromonomer, or norbornene-terminated macromonomer can then be polymerized, for example, in a RAFT polymerization process as described above, to form a first precursor bottlebrush polymer having a linear polyacrylate, polymethacrylate, or polynorbornene backbone and side chains comprising polyoxazoline segments extending from the linear polymer backbone, the polyoxazoline segments comprising terminal hydroxyl groups. The hydroxyl-terminated first precursor bottlebrush polymer is then reacted with glutaric anhydride to yield a second precursor bottlebrush polymer having a linear polyacrylate, polymethacrylate, or polynorbornene backbone and side chains comprising glutaric acid-terminated polyoxazoline segments extending from the linear polymer backbone. The glutaric acid-terminated second precursor bottlebrush polymer is then reacted with N-hydroxysuccinimide in the presence of a coupling agent to form a bottlebrush polymer 320 having a linear acrylate, polymethacrylate, or polynorbornene backbone and side chains comprising succinimidyl-glutaric acid-terminated polyoxazoline segments extending from the linear polymer backbone. In Figure 3 In some embodiments, n is an integer and can be in the range of, for example, 2 to 100, among other values.

[0075] In Figure 4 In another embodiment of the present disclosure shown, a reactive polysaccharide, more specifically, a reactive hyaluronic acid polymer, is formed. As Figure 4 In the presence of an ester coupling agent, such as N,N'-dicyclohexylcarbodiimide (DCC), the carboxyl groups of the polysaccharide (more specifically, the hyaluronic acid polymer 410) containing one or more uronic acid species are reacted with N-hydroxysuccinimide 412 to form a polymer 420 having a hyaluronic acid backbone and reactive succinimidyl ester side groups. In some embodiments, only a subset of the COOH groups are converted to succinimidyl esters.

[0076] The reactive polymers according to the present disclosure further include multi-armed and bottlebrush RAFT derivatized hydrophilic polymers. These polymers contain a multifunctional RAFT initiator residue and a plurality of polymer arms extending from the multifunctional RAFT initiator residue. The RAFT initiator can be selected from a RAFT initiator having a plurality of functional groups (e.g., 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, or more functional groups), the number of functional groups selected based on the number of arms / pendents desired. For example, the RAFT initiator can contain a plurality of trithiocarbonate functional groups.

[0077] In a further embodiment, the multifunctional RAFT agent, such as the compound of Formula I, Bis-MPA-RAFT dendrimers (CAS: 2421217-33-4), can be used in a RAFT polymerization process to provide a multi-armed polymer. Figure 5 In the specific embodiment shown, a polar aprotic vinyl monomer 512 (where X represents a range of polar aprotic vinyl monomers (PAVM)) and an unsaturated hydroxylated monomer (specifically, 1-hydroxyethyl acrylate 514) are copolymerized in a RAFT polymerization in the presence of a trithiocarbonate initiator 516, where R = aliphatic, alicyclic, or aromatic functionality, Y = aliphatic, alicyclic, or aromatic functionality. The resulting copolymer is then reacted with 4-cyano-4-[ (dodecylthiocarbonyl)thio]pentanoic acid 518 in the presence of a suitable coupling agent (e.g., a carbodiimide coupling agent such as N,N'-dicyclohexylcarbodiimide (DCC)) and a catalyst (e.g., 4-dimethylaminopyridine (DMAP)) to form a multifunctional RAFT agent 520, where n ranges from 5 to 5000 and m ranges from 2 to 100. The RAFT agent 520 is a linear polymer that can be used as an initiator in a subsequent RAFT polymerization process to provide a multi-armed / bottlebrush polymer.

[0078] In a further embodiment, the multifunctional RAFT agent, such as the compound of Formula I, Bis-MPA-RAFT dendrimers (CAS: 2421217-33-4), can be used in a RAFT polymerization process to provide a multi-armed polymer. Figure 6 In another specific embodiment shown, a polar aprotic diacrylate monomer 612, where X is a group representing a range of polar aprotic diacrylate monomers (PADA), is polymerized in a RAFT polymerization in the presence of a trithiocarbonate initiator 616, where R = alkyl, aryl, or cycloaliphatic linker, with or without a polar functionality to promote water solubility, Y = alkyl, aryl, cycloaliphatic, to form a multifunctional RAFT agent 620, where n ranges from 1 to 100. The linear polymer RAFT agent 620 can be used as an initiator in a subsequent RAFT polymerization process to provide a multi-armed / bottlebrush polymer in a reaction with a polar aprotic vinyl monomer (PAVM) feedstock.

[0079] In a further embodiment, the multifunctional RAFT agent, such as the compound of Formula I, Bis-MPA-RAFT dendrimers (CAS: 2421217-33-4), can be used in a RAFT polymerization process to provide a multi-armed polymer.

[0080]

[0081] I

[0082] Using the above and other RAFT initiators, RAFT polymerization can be carried out to form a polymer segment from one or more polar aprotic vinyl monomers. Examples of polar aprotic vinyl monomers include N-vinylpyrrolidone, acrylamide, dimethylacrylamide, N-vinylimidazole, 4-vinylimidazole, sodium 4-vinylbenzenesulfonate, and the like.

[0083] When the initiator comprises a trithiocarbonate group, the resulting polymer arm / pendant will comprise a terminal trithiocarbonate group. In some embodiments, the trithiocarbonate-terminated polymer arm / pendant is subjected to an amination step, thereby forming a thiol-terminated polymer arm / pendant, which is then subjected to a thiol-Michael addition reaction with an unsaturated hydroxylated compound, such as hydroxyethyl acrylate, among other possibilities, thereby providing a hydroxyl-terminated polymer arm / pendant. The hydroxyl-terminated polymer arm / pendant can then be reacted with glutaric anhydride, followed by reaction with N-hydroxysuccinimide, to form a multi-armed polymer having a plurality of polymer arms / pendants comprising succinimidyl-glutarate-terminated polymer segments, which segments are formed from one or more polar aprotic vinyl monomers, extending from the RAFT initiator residue.

[0084] The amination, thiol-Michael addition, and succinimidyl glutarate termination processes are illustrated in Scheme 1, where tributylphosphine (P(n-Bu)3) and n-hexylamine (n-C6H Figure 7 Amination of the trithiocarbonate compound 712 with tributylphosphine (P(n-Bu)3) and n-hexylamine (n-C6H 13 NH2) in tetrahydrofuran (THF) to yield thiol compound 714, where R is a bottlebrush polymer formed from a polar aprotic vinyl monomer as previously described, and X is a sacrificial alkyl, aryl, or alicyclic trithiocarbonate modifier. Thiol compound 714 is then reacted with hydroxyethyl acrylate 716 in a Michael addition reaction to provide compound 718 having a terminal hydroxyl group, which is then reacted with glutaric anhydride, followed by reaction with N-hydroxysuccinimide, to provide compound 720 having a terminal succinimidyl glutarate group. Alternatively, N-hydroxy-5-norbornene-2,3-dicarboxylic acid imide [HONB] can be used in place of N-hydroxysuccinimide to form the electrophilic reactive group.

[0085] In various aspects, the present disclosure provides a hydrogel comprising (a) a reactive polymer (e.g., a reactive bottlebrush polymer, a reactive multi-arm polymer, a reactive polysaccharide) as described above and (b) a crosslinking reaction product of a polyamino compound. For example, a reactive polymer comprising a reactive cyclic imide ester group can react with an amino group of a polyamino compound under basic conditions, e.g., at a pH range of about 7.4 to 11, more specifically, in some embodiments, at a pH range of about 9 to 11, to form an amide bond. As another example, a reactive polymer comprising a reactive unsaturated group (e.g., vinyl, acryloyl, methacryloyl, etc.) can react with an amino group of a polyamino compound through Michael addition under basic conditions, e.g., at a pH range of about 7.4 to 11, more specifically, in some embodiments, at a pH range of about 9 to 11, to form an amine bond.

[0086] Generally, polyamino compounds suitable for use in the present disclosure include, for example, small molecule polyamines (e.g., containing at least two amine groups, e.g., in certain embodiments, 3 to 20 amine groups or more), polymers having amine pendant groups, and branched polymers having amine end groups, including dendrimers having amine end groups. Polyamino compounds suitable for use in the present disclosure include those comprising a plurality of - (CH2) x -NH2groups, where x is 0, 1, 2, 3, 4, 5, or 6. Polyamino compounds suitable for use in the present disclosure include polyamino compounds comprising basic amino acid residues (including amino acid residues having two or more primary amine groups, such as lysine and ornithine), e.g., polyamines comprising 2 to 10 lysine and / or ornithine amino acid residues (e.g., di-lysine, tri-lysine, tetra-lysine, penta-lysine, di-ornithine, tri-ornithine, tetra-ornithine, penta-ornithine, etc.).

[0087] Specific examples of polyamino compounds that can be used as polyamino compounds include ethylene triamine, diethylene triamine, hexamethylene triamine, di(septamethylene) triamine, di(trimethylene) triamine, bis(hexamethylene) triamine, triethylene tetramine, tripropylene tetramine, tetraethylene pentamine, hexamethylene heptamine, pentaethylene hexamine, dimethyloctylamine, dimethyldecylamine, and JEFFAMINE polyether amines available from Huntsman Corporation, chitosan and derivatives thereof, and poly(allyl amine), among others.

[0088] In some embodiments, the polyamino compound can be substituted with one or more radio-opaque atoms (e.g., iodine or bromine). In particular embodiments, the polyamino compound can be substituted with iodine alone or with an iodinated moiety, e.g., one selected from one of the iodinated moieties described above.

[0089] In various embodiments, the crosslinked reaction products of the present disclosure are visible under fluoroscopy. In various embodiments, such crosslinked products have radiopacity greater than 100 Hounsfield Units (HU), desirably in the range of 100 HU to 250 HU to 500 HU to 750 HU to 1000 Hu to 2000 HU or higher (in other words, in a range between any two of the foregoing values). Such crosslinked products can be formed in vivo (e.g., using a delivery device as described below), or such crosslinked products can be formed in vitro and subsequently administered to a subject. Such crosslinked products can be applied to various biomedical applications, including implants, medical devices, and pharmaceutical compositions.

[0090] In some aspects of the present disclosure, a system is provided that is configured to deliver (a) an amino compound and (b) a reactive polymer as described above (e.g., a reactive bottlebrush polymer, a reactive multi-arm polymer, or a reactive polysaccharide). The polyamino compound and the reactive polymer are mixed under conditions such that the aminos of the polyamino compound and the reactive moieties of the reactive polymer crosslink to one another. In certain embodiments, those conditions include an environment having a basic pH, e.g., a pH in the range of about 7.4 to 11, more particularly, in some embodiments, a pH in the range of about 9 to 11. Such systems can be used to form crosslinked hydrogels in vivo or in vitro.

[0091] In some aspects of the present disclosure, a system is provided that includes (a) a first composition comprising a polyamino compound, e.g., as described herein, and (b) a second composition comprising a reactive polymer as described herein.

[0092] The first composition can be a first fluid composition comprising the polyamino compound, or a first dry composition comprising the polyamino compound, to which a suitable fluid such as water for injection, a saline solution, and the like can be added to form the first fluid composition. In addition to the polyamino compound, the first composition can comprise additives including therapeutic agents, imaging agents, colorants, tonicity adjusting agents, suspending agents, wetting agents, and pH adjusting agents as described below.

[0093] The second composition can be a second fluid composition comprising the reactive polymer, or a second dry composition comprising the reactive polymer, to which a suitable fluid such as water for injection, a saline solution, and the like can be added to form the second fluid composition. In addition to the reactive polymer, the second composition can comprise additives including therapeutic agents, imaging agents, colorants, tonicity adjusting agents, suspending agents, wetting agents, and pH adjusting agents as described below.

[0094] In some embodiments, the polyamino compound is initially mixed with the reactive polymer at an acidic pH at which crosslinking between the reactive moieties of the reactive polymer and the aminos of the polyamino compound is inhibited. Then, when crosslinking is desired, the pH of the mixture of the polyamino compound and the reactive polymer is changed from the acidic pH to a basic pH, resulting in crosslinking between them, thereby forming a crosslinked product.

[0095] In one particular embodiment, the system comprises (a) a first composition comprising a polyamino compound as described above, (b) a second composition comprising a reactive polymer as described above, and (c) a third composition, in particular a promoter composition, containing a promoter configured to accelerate the crosslinking reaction between the polyamino compound and the reactive polymer.

[0096] The first composition can be a first fluid composition comprising a polyamino compound buffered to an acidic pH, or a first dry composition comprising a polyamino compound and an acidic buffer composition, to which a suitable fluid such as water for injection, a salt solution, or the like can be added to form the first fluid composition comprising a polyamino compound buffered to an acidic pH. In some embodiments, for example, the acidic buffer composition can comprise sodium phosphate monobasic or the like. The first fluid composition comprising a polyamino compound can have a pH in the range of, for example, about 3 to about 5. In addition to the polyamino compound, the first composition can comprise additives including therapeutic agents, imaging agents, colorants, tonicity adjusting agents, suspending agents, wetting agents, and pH adjusting agents as described below.

[0097] The second composition can be a second fluid composition comprising a reactive polymer, or a second dry composition comprising a reactive polymer, from which a fluid composition is formed, for example, by adding a suitable fluid such as water for injection, a salt solution, or the first fluid composition comprising a polyamino compound buffered to an acidic pH. In addition to the radio-opaque reactive polymer, the second composition can comprise additives including therapeutic agents, imaging agents, colorants, tonicity adjusting agents, suspending agents, wetting agents, and pH adjusting agents as described below.

[0098] In one particular embodiment, the first composition is a first fluid composition comprising a polyamino compound buffered to an acidic pH, and the second composition comprises a dry composition containing a reactive polymer. The first composition can then be mixed with the second composition to provide a prepared fluid composition buffered to an acidic pH and comprising a polyamino compound and a reactive polymer. In a particular example, a syringe containing a first fluid composition comprising a polyamino compound buffered to an acidic pH can be provided, and a vial containing a dry composition (e.g., a powder) comprising a reactive polymer can be provided. The first fluid composition can then be injected into the vial containing the reactive polymer using the syringe to form a prepared fluid composition containing a polyamino compound and a reactive polymer, which can be withdrawn into the syringe for administration.

[0099] The accelerator composition can be a fluid accelerator composition buffered to a basic pH, or a dry composition comprising a basic buffer composition to which a suitable fluid such as water for injection, a salt solution, and the like can be added to form a fluid accelerator composition buffered to a basic pH. For example, the basic buffer composition can comprise sodium borate and disodium hydrogen phosphate, among others. The pH of the fluid accelerator composition can be, for example, from about 9 to about 11. In addition to the above, the fluid accelerator composition can also comprise additives, including those described below.

[0100] Additives for use in the compositions described herein include therapeutic agents, imaging agents, coloring agents, tonicity adjusting agents, suspending agents, wetting agents, and pH adjusting agents.

[0101] Examples of therapeutic agents include anti-thrombotic agents, anti-coagulants, anti-platelet agents, thrombolytic agents, anti-proliferative agents, anti-inflammatory agents, proliferation inhibitors, anti-restenotic agents, smooth muscle cell inhibitors, antibiotics, anti-bacterial agents, analgesic agents, anesthetic agents, growth factors, growth factor inhibitors, cell adhesion inhibitors, cell adhesion promoters, anti-angiogenic agents, cytotoxic agents, chemotherapeutic agents, checkpoint inhibitors, immunomodulatory cytokines, T-cell agonists, STING (stimulator of interferon genes) agonists, anti-metabolites, alkylating agents, microtubule inhibitors, hormones, hormone antagonists, monoclonal antibodies, anti-mitotic drugs, immunosuppressive agents, tyrosine and serine / threonine kinases, proteasome inhibitors, matrix metalloproteinase inhibitors, Bcl-2 inhibitors, DNA alkylating agents, spindle poisons, poly (DP-ribose) polymerase (PARP) inhibitors, and combinations thereof.

[0102] Other specific examples of imaging agents include (a) fluorescent dyes such as fluorescein, indocyanine green, or fluorescent proteins (e.g., green, blue, blue-green fluorescent proteins), (b) contrast agents for use in conjunction with magnetic resonance imaging (MRI), including contrast agents containing elements that form paramagnetic ions, such as Gd(III), Mn(II), Fe(III), and compounds containing them (including chelates), such as gadolinium ions chelated with diethylenetriaminepentaacetic acid, (c) contrast agents for use in conjunction with ultrasound imaging, including organic and inorganic echogenic particles (i.e., particles that cause an increase in reflected ultrasound energy) or organic and inorganic echolucent particles (i.e., particles that cause a decrease in reflected ultrasound energy), (d) contrast agents for use in conjunction with near-infrared (NIR) imaging, which can be selected to impart near-infrared fluorescence to the hydrogels of the present disclosure, thereby allowing deep tissue imaging and device marking, such as NIR-sensitive nanoparticles, such as gold nanoshells, carbon nanotubes (e.g., nanotubes derivatized with hydroxyl or carboxyl groups, such as partially oxidized carbon nanotubes), dye-containing nanoparticles, such as dye-doped nanofibers and dye-encapsulated nanoparticles, and semiconductor quantum dots, etc., and NIR-sensitive dyes, such as cyanine dyes, squaraines, phthalocyanines, porphyrin derivatives, and BODIPY analogs, etc., (e) imageable radioisotopes, including99mTc,201Th,51Cr,67Ga,68Ga,111In,64Cu,89Zr,59Fe,42K,82Rb,24Na,45Ti,44Sc,51Cr, and177Lu, etc., and (f) radiopaque contrast agents (in addition to any radio-opaque iodine or bromine atoms present), such as metal particles, e.g., particles of tantalum, tungsten, rhenium, niobium, molybdenum, and alloys thereof, where the metal particles can be spherical or non-spherical. Other examples of radiopaque contrast agents include non-ionic radiopaque contrast agents, such as iohexol, iodixanol, ioversol, iopamidol, ioxilan, or iopromide, ionic radiopaque contrast agents, such as diatrizoate, iothalamate, metrizoate, or ioxaglate, and iodinated oils, including ethiodized poppyseed oil (available as Lipiodol®).

[0103] Examples of colorants include brilliant blue (e.g., brilliant blue FCF, also known as FD&C blue 1), indigocarmine (also known as FD&C blue 2), indigocarmine lake, FD&C blue 1 lake, and methylene blue (also known as methylene blue chloride), among others.

[0104] Examples of additives also include tonicity adjusting agents such as sugars (e.g., glucose, lactose, etc.), polyols (e.g., glycerol, propylene glycol, mannitol, sorbitol, etc.), and inorganic salts (e.g., potassium chloride, sodium chloride, etc.), among others, suspending agents, including various surfactants, wetting agents, and polymers (e.g., albumin, PEO, polyvinyl alcohol, block polymers, etc.), among others, and pH adjusting agents, including various buffer solutes.

[0105] A prepared fluid composition buffered to an acidic pH and comprising a polyamino compound and a reactive polymer as described above, and a fluid facilitator composition buffered to a basic pH as described above, can be combined in vivo or in vitro to form a crosslinked hydrogel.

[0106] In various embodiments, a system is provided that includes one or more delivery devices that deliver a first composition and a second composition to a subject.

[0107] In some embodiments, the system can include a delivery device that includes a first reservoir containing a first composition comprising a polyamino compound as described above and a second reservoir containing a second composition comprising a reactive polymer as described above, the radio-opaque reactive copolymer comprising a plurality of reactive moieties that react with amino moieties of the polyamino compound.

[0108] In some embodiments, the system can include a delivery device that includes a first reservoir containing a first composition comprising a polyamino compound and a reactive polymer and buffered to an acidic pH, a prepared fluid composition as described above, and a second reservoir containing a second composition, such as the aforementioned fluid facilitator composition.

[0109] In either case, in operation, the first and second compositions are dispensed from the first and second reservoirs and combined, whereby the polyamino compound and the reactive polymer crosslink with one another to form a crosslinked hydrogel.

[0110] In particular embodiments, and with reference to Figure 8In some embodiments, the system can include a delivery device 810 comprising a dual barrel syringe comprising a first barrel 812a having a first barrel outlet 814a (the first barrel containing a first composition, a first plunger 816a movable in the first barrel 812a), a second barrel 812b having a second barrel outlet 814b (the second barrel 812b containing a second composition, and a second plunger 816b movable in the second barrel 812b). In some embodiments, the device 810 can further include a mixing portion 818 having a first mixing portion inlet 818ai in fluid communication with the first barrel outlet 814a, a second mixing portion inlet 818bi in fluid communication with the second barrel outlet, and a mixing portion outlet 818o.

[0111] In some embodiments, the device can further include a cannula or catheter configured to receive the first and second fluid compositions from the first and second barrels. For example, the cannula or catheter can be configured to form a fluid connection with the outlet of the mixing portion by attaching the cannula or catheter to the outlet of the mixing portion (e.g., via a suitable fluid connector such as a luer connector).

[0112] As another example, the catheter can be a multi-lumen catheter comprising a first lumen and a second lumen, a proximal end of the first lumen configured to form a fluid connection with the first barrel outlet, and a proximal end of the second lumen configured to form a fluid connection with the second barrel outlet. In some embodiments, the multi-lumen catheter can include a mixing portion having a first mixing portion inlet in fluid communication with a distal end of the first lumen, a second mixing portion inlet in fluid communication with a distal end of the second lumen, and a mixing portion outlet.

[0113] During operation, when the first and second plungers are depressed, the first and second fluid compositions are dispensed from the first and second barrels, whereupon the first and second fluid compositions interact and ultimately crosslink to form a crosslinked hydrogel that is applied to or into a tissue of a subject. For example, the first and second fluid compositions can enter the mixing portion from the first and second barrels via the first and second mixing portion inlets, whereby the first and second fluid compositions mix to form a mixture that exits the mixing portion via the mixing portion outlet. In some embodiments, the cannula or catheter is attached to the mixing portion outlet, thereby allowing the mixture to be applied to the subject after passing through the cannula or catheter.

[0114] As another example, the first fluid composition can enter a first lumen of the multi-lumen catheter from the first tube outlet, and the second fluid composition can enter a second lumen of the multi-lumen catheter from the second tube outlet. In some embodiments, the first and second fluid compositions can enter a mixing portion at a distal end of the multi-lumen catheter from the first and second lumen, respectively, via the first and second mixing portion inlets, whereupon the first and second fluid compositions mix in the mixing portion to form a mixture that exits the mixing portion via the mixing portion outlet.

[0115] Regardless of the type of device used to mix the first and second fluid compositions or how the first and second fluid compositions are mixed, after the mixture of the first and second fluid compositions is formed, the mixture is initially in a fluid state and can be administered to a subject (e.g., a mammal, particularly a human) by various techniques. Alternatively, the first and second fluid compositions can be independently administered to a subject, and the fluid mixture of the first and second fluid compositions is formed within the subject or on the body surface. In either method, the fluid mixture of the first and second fluid compositions is formed and used for various medical procedures.

[0116] For example, in uses such as the treatment of disease and cancer, and the repair and regeneration of tissue, the first and second fluid compositions or the fluid mixture thereof can be injected to provide spacing between tissues, the first and second fluid compositions or the fluid mixture thereof can be injected (e.g., in the form of a water blister) to provide fiducial markers, the first and second fluid compositions or the fluid mixture thereof can be injected for tissue augmentation or regeneration, the first and second fluid compositions or the fluid mixture thereof can be injected as a filler or replacement for soft tissue, the first and second fluid compositions or the fluid mixture thereof can be injected to provide mechanical support to damaged tissue, the first and second fluid compositions or the fluid mixture thereof can be injected as a stent, and / or the first and second fluid compositions or the fluid mixture thereof can be injected as a carrier for a therapeutic agent.

[0117] Upon administration of the compositions of the present disclosure (either as the first and second fluid compositions that are mixed in vivo separately, or as the fluid mixture of the first and second fluid compositions), a crosslinked hydrogel is ultimately formed at the site of administration.

[0118] Upon administration, the compositions of the present disclosure can be imaged using a suitable imaging technique. The imaging technique can be, for example, an ultrasound imaging technique, a magnetic resonance imaging (MRI), or an X-ray based imaging technique, such as computed tomography or X-ray fluoroscopy.

[0119] From the foregoing, it is seen that the compositions of the present disclosure can be used in a variety of medical procedures, including the following: procedures to implant fiducial markers comprising crosslinked products of the first and second fluid compositions, procedures to implant tissue regeneration scaffolds comprising crosslinked products of the first and second fluid compositions, procedures to implant tissue supports comprising crosslinked products of the first and second fluid compositions, procedures to implant tissue bulking agents comprising crosslinked products of the first and second fluid compositions, procedures to implant depots of therapeutic agents comprising crosslinked products of the first and second fluid compositions, procedures to augment tissue comprising implanting crosslinked products of the first and second fluid compositions, procedures to introduce crosslinked products of the first and second fluid compositions between a first tissue and a second tissue to separate the first tissue from the second tissue.

[0120] The first fluid composition and the second fluid composition, the fluid mixture of the first fluid composition and the second fluid composition, or the crosslinked product of the first fluid composition and the second fluid composition can be injected in conjunction with a variety of medical procedures including the following: injection for spacing between the prostate or the vagina and rectum in radiation therapy for rectal cancer, injection for spacing between the rectum and the prostate in radiation therapy for prostate cancer, subcutaneous injection for palliative treatment of prostate cancer, transurethral or submucosal injection for female stress urinary incontinence, intravesical injection for urinary incontinence, uterine cavity injection for Asherman's syndrome, submucosal injection for anal incontinence, percutaneous injection for heart failure, intramyocardial injection for heart failure and dilated cardiomyopathy, transendocardial injection for myocardial infarction, intra-articular injection for osteoarthritis, spinal injection for spinal fusion and spinal, oral and maxillofacial and orthopedic trauma surgery, spinal injection for posterolateral lumbar fusion, intradiscal injection for degenerative disc disease, injection between the pancreas and the duodenum for imaging of pancreatic cancer, resection bed injection for imaging of oropharyngeal cancer, injection around the tumor bed for imaging of bladder cancer, submucosal injection for gastrointestinal tumors and polyps, parietal pleural injection for lung biopsy, kidney injection for type 2 diabetes and chronic kidney disease, kidney cortex injection for chronic kidney disease from congenital anomalies of the kidney and urethra, intravitreal injection for neovascular age-related macular degeneration, intratympanic injection for sensorineural hearing loss, dermal injection for the correction of wrinkles, folds and rhytides, signs of facial fat reduction, volume loss, superficial to deep contour defects, depressed skin scars, perioral wrinkles, lip augmentation, facial lipoatrophy, stimulation of natural collagen production.

[0121] In the case of in vitro formation, the crosslinked hydrogel can be in any desired form, including a slab, a cylinder, a coating, or a particle. In some embodiments, the crosslinked hydrogel is dried and then granulated into particles of suitable size. Granulation can be by any suitable method, such as by milling (including cryogenic milling), homogenization, crushing, grinding, trituration, and the like. The particles can be classified and separated using sieving or other known techniques. The size of the crosslinked hydrogel particles formed using the above and other techniques can vary widely, such as having an average size of 50-950 microns.

[0122] In addition to the crosslinked hydrogel as described above, the crosslinked hydrogel composition according to the present disclosure can include additives, including therapeutic agents, imaging agents, colorants, tonicity adjusting agents, suspending agents, wetting agents, and pH adjusting agents as described above.

[0123] In various embodiments, a kit is provided that includes one or more delivery devices for delivering the crosslinked hydrogel to a subject. Such a system can include one or more of a syringe tube, which can or can not contain the crosslinked hydrogel particles described herein; a vial, which can or can not contain the crosslinked hydrogel particles described herein; a needle; a flexible tube (e.g., adapted to fluidly connect the needle with the syringe); and an injectable liquid, such as water for injection, normal saline, or phosphate buffered saline. Whether provided in the form of a syringe, vial, or other reservoir, the crosslinked hydrogel particles can be provided in dry form, such as a powder, or in a ready for injection form, such as an injectable hydrogel form (e.g., a suspension of crosslinked hydrogel particles).

[0124] Figure 9 A syringe 10 is shown, which provides a reservoir of the crosslinked hydrogel composition as described above. The syringe 10 can include a tube 12, a plunger 14, and one or more stoppers 16. The tube 12 can include, for example, a luer adapter (or other suitable adapter / connector) at a distal end 18 of the tube 12 for attachment to an injection needle 50 via a flexible conduit 29. A proximal end of the conduit 29 can include a suitable connector 20 for receiving the tube 12. In other examples, the tube 12 can be directly connected to the injection needle 50. The injection tube 12 can serve as a reservoir containing the crosslinked hydrogel composition 15 for injection through the needle 50.

[0125] The crosslinked hydrogel compositions described herein can be used for a variety of purposes.

[0126] For example, the crosslinked hydrogel composition can be injected to provide spacing between tissues in uses such as treatment of disease and cancer and repair and regeneration of tissues, the crosslinked hydrogel composition can be injected (e.g., in the form of a water bubble) to provide fiducial markers, the crosslinked hydrogel composition can be injected for tissue augmentation or regeneration, the crosslinked hydrogel composition can be injected as a filler or replacement for soft tissue, the crosslinked hydrogel composition can be injected to provide mechanical support to damaged tissue, the crosslinked hydrogel composition can be injected as a scaffold, and / or the crosslinked polymer composition can be injected as a carrier for a therapeutic agent for uses such as treatment of disease and cancer and repair and regeneration of tissues.

[0127] After administration, the crosslinked hydrogel composition of the present disclosure can be imaged using suitable imaging techniques.

[0128] As described above, the crosslinked hydrogel composition of the present disclosure can be used in various medical procedures, including the following: procedures for implanting fiducial markers comprising crosslinked hydrogels, procedures for implanting tissue regeneration scaffolds comprising crosslinked hydrogels, procedures for implanting tissue supports comprising crosslinked hydrogels, procedures for implanting tissue bulking agents comprising crosslinked hydrogels, procedures for implanting therapeutic agent-containing depots comprising crosslinked hydrogels, procedures for tissue augmentation comprising implanting crosslinked hydrogels, procedures for introducing crosslinked hydrogels between a first tissue and a second tissue to space the first tissue from the second tissue.

[0129] The crosslinked hydrogel compositions can be injected with various medical procedures, including the following: injection for spacing between the prostate or the vagina and rectum in rectal cancer radiation therapy, injection for spacing between the rectum and prostate in prostate cancer radiation therapy, subcutaneous injection for palliative treatment of prostate cancer, transurethral or submucosal injection for female stress urinary incontinence, intravesical injection for urinary incontinence, uterine cavity injection for Asherman's syndrome, submucosal injection for anal incontinence, percutaneous injection for heart failure, intramyocardial injection for heart failure and dilated cardiomyopathy, transendocardial injection for myocardial infarction, intra-articular injection for osteoarthritis, spinal injection for spinal fusion and spinal, oral maxillofacial and orthopedic trauma surgery, spinal injection for posterolateral lumbar fusion, intradiscal injection for degenerative disc disease, injection between the pancreas and duodenum for pancreatic cancer imaging, resection bed injection for oropharyngeal cancer imaging, injection around the tumor bed for bladder cancer imaging, submucosal injection for gastrointestinal tumors and polyps, internal visceral pleural injection for lung biopsy, kidney injection for type 2 diabetes and chronic kidney disease, kidney cortex injection for chronic kidney disease from congenital abnormalities of the kidney and urethra, intravitreal injection for neovascular age-related macular degeneration, intratympanic injection for sensorineural hearing loss, dermal injection for the correction of wrinkles, folds and rhytides, signs of facial fat reduction, volume reduction, depth-to-depth contour defects, concave skin scars, perioral wrinkles, lip augmentation, facial fat atrophy, stimulation of natural collagen production.

[0130] The crosslinked hydrogel compositions according to the present disclosure include smooth compositions for medical applications, compositions for therapeutic agent release (e.g., by including one or more therapeutic agents in the matrix of the crosslinked hydrogel), and implants (which can be formed in vitro or in vivo) (e.g., compositions for use as tissue markers, compositions that act as spacers to reduce the side effects of off-target radiation therapy, cosmetic compositions, etc.).

Claims

1. A reactive bottlebrush polymer comprising a polymer backbone and a plurality of polymer side chains attached to the polymer backbone, at least a portion of the side chains each comprising a hydrophilic polymer segment covalently attached to the polymer backbone, and a reactive moiety covalently attached to the hydrophilic polymer segment at a side chain terminus opposite the polymer backbone.

2. The reactive bottlebrush polymer of claim 1, wherein the reactive moiety comprises an electrophilic group or an alkenyl-containing group.

3. The reactive bottlebrush polymer of claim 1, wherein the reactive moiety comprises a cyclic imide ester group, an imidazole ester group, an imidazole carboxylate group, a benzotriazole ester group, an acryloyl group, or a methacryloyl group.

4. The reactive bottlebrush polymer of any one of claims 1-3, wherein the hydrophilic polymer segment is selected from a poly(ethylene oxide)-containing segment, a poly(amino acid)-containing segment, a poly(oxazoline)-containing segment, or a hydrophilic polymer segment containing one or more residues of a polar aprotic vinylic monomer.

5. The reactive bottlebrush polymer of any one of claims 1-4, wherein the hydrophilic polymer segment is an iodine-containing hydrophilic polymer segment.

6. The reactive bottlebrush polymer of any one of claims 1-5, further comprising a cyclic anhydride residue between the hydrophilic polymer segment and the reactive moiety.

7. The reactive bottlebrush polymer of claim 6, wherein the cyclic anhydride residue is an iodine-containing cyclic anhydride residue.

8. The reactive bottlebrush polymer of any one of claims 6-7, wherein the cyclic anhydride residue is selected from a residue of an iodine-containing or non-iodine-containing glutaric anhydride compound, a residue of an iodine-containing or non-iodine-containing succinic anhydride compound, a residue of an iodine-containing or non-iodine-containing malonic anhydride compound, a residue of an iodine-containing or non-iodine-containing adipic anhydride compound, and a residue of an iodine-containing or non-iodine-containing diglycolic anhydride compound.

9. A system for forming a hydrogel composition comprising (a) a polyamino compound and (b) the reactive bottlebrush polymer of any one of claims 2-8.

10. The system of claim 9, wherein the system comprises a first composition comprising the polyamino compound and a second composition comprising the reactive bottlebrush polymer.

11. The system of claim 10, further comprising an accelerator composition.

12. The system of any one of claims 9-11, further comprising a delivery device.

13. A crosslinked hydrogel composition comprising (a) a polyamino compound and (b) a crosslinked reaction product of the bottlebrush polymer of any one of claims 2-8.

14. A method of treatment comprising administering to a subject a mixture comprising (a) a polyamino compound and (b) the reactive bottlebrush polymer of any one of claims 2-8 under conditions such that the polyamino compound and the reactive bottlebrush polymer crosslink upon administration.

15. A method of treatment comprising administering to the body of a subject the reactive bottlebrush polymer of any one of claims 2-8 under conditions such that the reactive bottlebrush polymer reacts with a naturally occurring amine in or on the body of the subject after administration.

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