CN118215692A - Crosslinked polymer chelant compositions and uses thereof - Google Patents

Abstract

The composition comprises (i) a cross-linked polymeric chelating agent comprising a plurality of cross-linked polyamine polymer backbones and one or more chelating agents covalently coupled thereto, and (ii) an agent selected from the group consisting of antacids, histamine H2-receptor antagonists, proton pump inhibitors, and combinations thereof. Also disclosed are methods of using compositions comprising cross-linked polymer chelators in combination with agents, e.g., for removing metals from a culture medium or treating iron overload diseases.

Description

Crosslinked polymer chelant compositions and uses thereof

Cross Reference to Related Applications

The present application claims priority from U.S. provisional application No. 63/233,024 filed on day 13 8 of 2021; and priority of U.S. provisional application No. 63/316,831 filed on 3/4 of 2022, which is incorporated herein by reference in its entirety.

Background

Metals such as cadmium, lead and arsenic are extremely toxic to organisms. Wastewater discharge may be a major source of heavy metal release into the environment. In the last decade, the removal of heavy metal ions from industrial wastewater has received considerable attention, as these components can accumulate in the organism. Once these toxic metals accumulate in the human body, they can cause renal failure, damage to the nervous system, bone injury, and other serious diseases. The necessity to reduce the content of heavy metal ions in the environment has led to an increasing interest in technologies for selectively removing such toxic metals.

There are 35 metals that are of interest for occupational or residential exposure; of which 23 metals are heavy elements or "heavy metals". Heavy metals are chemical elements and have a specific gravity at least 5 times that of water. Small amounts of heavy metals are common in our environment and diet, and indeed, in some cases, are essential elements for health, but any major element may lead to acute or chronic poisoning. Heavy metal poisoning can lead to impaired or reduced mental and central nervous functions, reduced energy levels, and impaired blood components, lung, kidney, liver, and other vital organs. Long-term exposure may lead to slow progression of the body, muscle and neurodegenerative processes, similar to alzheimer's disease, parkinson's disease, muscular dystrophy and multiple sclerosis. Allergy is not uncommon and prolonged repeated exposure to certain metals or compounds thereof may even be carcinogenic.

A heavy metal of particular interest is iron. Iron is an essential and ubiquitous element in all life forms, is involved in a variety of biological processes, and is critical to many critical human biological processes. However, excessive iron in the body may lead to toxic effects.

Iron overload is a serious complication of patients with beta-thalassemia and is also the focus of its treatment. In patients not receiving blood transfusion, iron absorption abnormalities lead to increased iron load in the body, estimated to increase by 2-5 grams per year. Patients undergoing regular blood transfusion etc. may result in doubling of iron accumulation. If not treated in time, iron accumulation can cause progressive damage to the liver, heart and endocrine system. Available iron is deposited in parenchyma and reticuloendothelial cells. When iron load increases, the iron binding capacity of serum transferrin exceeds standard, and a plasma iron non-transferrin binding moiety (NTBI) appears. NTBI can generate hydroxyl radicals and cause dangerous tissue damage. Iron accumulates at different rates in different organs, each of which responds in a characteristic manner to NTBI-induced damage and intracellular variable iron pool (LIP) -induced damage.

Current treatments for iron overload disorders include chelation therapy to sequester iron and reduce its bioavailability. In one embodiment, chelation therapy may be performed with Desferrioxamine (DFO), which is administered by subcutaneous infusion. Drugs that can be administered orally include deferiprone (deferiprone) and enregex (Exjade). DFO therapy has been reported to suffer from several drawbacks, including a narrow therapeutic window and a lack of oral bioavailability. Thus, 8-12 hours of infusion administration are required daily. DFO is not readily absorbed through the intestinal tract and must be intravenously injected, and is not an ideal chelator because systemic side effects have been reported. In addition, many of the significant toxicities associated with drugs raise concerns over their use. Serious adverse effects such as neutropenia, granulocytopenia, hypersensitivity and vascular inflammation have also been reported following oral administration of deferiprone and enregex.

One possible way to avoid the use of systemic iron chelators is to inhibit the absorption of iron from the gastrointestinal tract by oral administration of an iron chelator that selectively chelates and removes excess dietary iron from the GI. Non-absorbent polymer therapies that act by sequestering some of the unwanted ionic species in the gastrointestinal tract have been clinically successful. The use of non-absorbable polymer therapies is particularly relevant to intermediate thalassemia and hemochromatosis. Iron binding polymers have considerable potential in this therapeutic approach because they can bind iron effectively, forming non-toxic, inert complexes that are not absorbed by the gastrointestinal tract, thereby reducing intestinal absorption of iron.

Microorganisms have developed complex Fe (III) collection and transport systems involving siderophores. Siderophores are low molecular weight chelators capable of binding Fe (III) ions with high specificity. The iron binding affinity of siderophores is far superior to that of currently available iron chelating therapies. Enterobacterin is a naturally occurring tri-catechol siderophore, the most potent Fe (III) chelator known, with a relative iron binding constant of 35.5. Since almost all iron is absorbed in the gastrointestinal tract, new generation iron chelators must achieve significantly higher iron binding and selectivity, with low toxicity and low side effects. Researchers have synthesized small molecule siderophore mimics; however, compounds that directly mimic siderophores are expected to enhance bacterial absorption of iron. There is a need for a new iron chelator that can tightly bind iron and remove it from the body.

Disclosure of Invention

In general, the present invention includes novel compositions and systems for metal chelation. In some embodiments, the present disclosure provides compositions comprising crosslinked polymeric chelants. The polymeric chelator may include a polymer coupled to a metal chelator and an agent, such as an antacid, histamine H2-receptor agonist, proton pump inhibitor, or combination thereof.

In one aspect, the present invention provides a composition comprising (i) a polymeric chelant comprising a plurality of polyamine polymer backbones and one or more chelants; (ii) An agent selected from the group consisting of antacids, histamine H2-receptor antagonists, proton pump inhibitors, and combinations thereof, wherein one or more chelating agents are covalently coupled to one or more primary and/or secondary amines (e.g., one or more primary amines) of at least one of the plurality of polyamine polymer backbones; and wherein the plurality of polyamine polymer backbones are crosslinked with a plurality of crosslinking agents. Examples of cross-linked polymeric chelators include one or any combination of the following alone.

The composition of the present invention, wherein each of the plurality of polyamine polymer backbones comprises a polyamine polymer having the following molecular weight (weight average molecular weight; "Mw"): 1-50kDa (e.g., 2-30kDa, 5-25kDa, 10-20kDa, 2,1kDa, 2kDa, 3kDa, 4kDa, 5kDa, 10kDa, 15kDa, 20kDa, 25kDa, 30kDa, 35kDa, 40kDa, 45kDa or 50 kDa).

The composition according to the present invention, wherein each polyamine polymer backbone comprises repeating monomer units having the structure:

Wherein L ₁ is C ₁-C₆ alkylene, L ₂ is a bond or C ₁-C₆ alkylene, R is H or C (O) R ', wherein R' is H, C ₁-C₆ alkyl or C ₆-C₁₂ aryl. As used herein, "alkylene" refers to a divalent straight chain saturated hydrocarbon group or a branched saturated hydrocarbon group. As used herein, "alkyl" refers to a branched monovalent saturated aliphatic radical or a straight monovalent saturated aliphatic radical containing only C and H when unsubstituted. As used herein, the term "aryl" refers to any monocyclic or fused ring bicyclic ring system containing only carbon atoms in the ring, which has aromatic character in terms of electron distribution throughout the ring system.

The composition according to the invention, wherein the polyamine polymer backbones each comprise polyallylamine.

The composition according to the invention, wherein the polyamine polymer backbones each comprise poly (lysine).

The composition according to the invention, wherein the agent is an antacid.

The composition according to the present invention, wherein the antacid is CaCO ₃、NaHCO₃、MgCO₃、Mg(OH)₂、MgO、Al(OH)₃ or dimethicone.

The composition according to the invention, wherein each of the plurality of crosslinking agents independently has the structure:

Wherein R ₁ and R ₂ are independently selected from:

R' is C ₁-C₆ alkyl; n is 0, 1 or 2; as used herein, "heteroalkylene" refers to a divalent straight or branched hydrocarbon group in which one or more carbon atoms are replaced with heteroatoms (e.g., O, N or S), "cycloalkylene" refers to a divalent monocyclic hydrocarbon group, "arylene" refers to a divalent, monocyclic, bicyclic, or polycyclic aromatic hydrocarbon group, and "heterocyclylene" refers to a divalent aryl group containing 1,2, 3, or 4 heteroatoms in the ring and the remaining ring atoms containing carbon atoms.

The composition according to the invention, wherein each of the plurality of crosslinking agents has the following structure:

the composition according to the invention, wherein the polymeric chelant comprises a plurality of groups, each having the following structure:

the composition according to the invention, wherein L ₃ is methylene.

The composition according to the invention, wherein each of the plurality of crosslinking agents has the following structure:

The composition according to the invention, wherein the polymeric chelant comprises a plurality of groups, each having the structure:

The composition according to the invention, wherein L ₃ is polyethylene glycol.

The composition according to the invention, wherein the polyethylene glycol has a molecular weight (number average molecular weight; "Mn") of 200 daltons to 6000 daltons (e.g. 400 daltons to 6000 daltons, 600 daltons to 6000 daltons, 1000 daltons to 6000 daltons, 2000 daltons to 6000 daltons, 400 daltons to 2000 daltons, 600 daltons to 2000 daltons, 1000 daltons to 2000 daltons, or 200 daltons, 400 daltons, 600 daltons, 1000 daltons, 2000 daltons or 6000 daltons).

The composition according to the invention, wherein the polyethylene glycol has a molecular weight (Mn) of 400 daltons to 2500 daltons.

The composition according to the invention, wherein the polyethylene glycol has a molecular weight (Mn) of 800 daltons and 2200 daltons.

The composition according to the invention, wherein each of the plurality of crosslinking agents is selected from:

the composition according to the present invention, wherein each of the plurality of crosslinking agents is a hydrophilic crosslinking agent.

The composition according to the invention, wherein the plurality of crosslinking agents comprises individual crosslinking agents having a molecular weight of 200 daltons to 6000 daltons (Mn).

The composition according to the invention, wherein the plurality of crosslinking agents comprises individual crosslinking agents having a molecular weight of 400 daltons to 2500 daltons (Mn).

The composition according to the invention, wherein the plurality of crosslinking agents comprises individual crosslinking agents having a molecular weight of 800 daltons to 2200 daltons (Mn).

The composition according to the present invention, wherein the plurality of crosslinking agents crosslink to the polyamine polymer backbone at a density of about 0.01% to 10% (e.g., 0.01% to 7.5%, 0.01% to 5%, 0.01% to 2%, 0.05% to 7.5%, 0.05% to 5%, 0.05% to 2%, or 0.01%, 0.05%, 0.1%, 0.2%, 0.5%, 0.75%, 1%, 2%, 5%, 7.5%, or 10%) based on the molar ratio of total amine in the polyamine polymer backbone.

The composition according to the invention, wherein the plurality of crosslinking agents crosslink to the polyamine polymer backbone at a density of less than or equal to 1% based on the molar ratio of total amine in the polyamine polymer backbone.

The composition according to the invention wherein one or more chelating agents each comprise a phenyl group substituted with at least two hydroxyl groups (e.g., two hydroxyl groups), and the at least two hydroxyl groups comprise an vicinal diol.

The composition according to the invention wherein the one or more chelating agents each comprise 2, 3-dihydroxybenzoic acid.

The composition according to the invention, wherein the polymeric chelant comprises a plurality of groups, each having the structure:

The composition according to the invention wherein the one or more chelating agents each comprise a derivative of a metal chelating agent moiety.

The composition according to the invention wherein the one or more chelating agents each comprise deferoxamine, phytic acid, oxalic acid, polyglycerol, polyphenols, benzene-1, 2-diol, benzene-1, 2, 3-triol, 1, 10-phenanthroline or derivatives of N, N-bis (2-hydroxyphenyl) ethylenediamine-N, N' -diacetic acid.

The composition according to the invention, wherein the one or more chelating agents are capable of chelating heavy metals.

The composition according to the present invention, wherein the one or more chelating agents are capable of chelating aluminum, arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury or combinations thereof. The composition according to the present invention, wherein one or more chelating agents may selectively bind iron in the presence of aluminum, arsenic, cadmium, chromium, copper, lead, manganese, mercury or combinations thereof.

The composition according to the invention, wherein the one or more chelating agents are capable of chelating iron.

The compositions according to the present invention wherein one or more chelating agents are coupled to the polyamine polymer backbone and 5-30% (e.g., 5-25%, 10-20%, 15-20%, 5%, 10%, 15%, 20%, 25%, or 30%) of the amine on the one or more chelating agents.

The composition according to the present invention, wherein the polymeric chelant comprises a plurality of polymeric chelant particles, each polymeric chelant particle comprising a plurality of polyamine polymer backbones and one or more chelants.

The composition according to the present invention, wherein the polymeric chelant comprises a plurality of polymeric chelant particles, each polymeric chelant particle comprising a plurality of polyamine polymer backbones and one or more chelants, and wherein at least 90% (e.g., at least 95% or at least 99%) of the plurality of polymeric chelant particles have a particle size of 300 μm or less (e.g., as measured by laser diffraction).

The composition according to the present invention, wherein the polymeric chelant comprises a plurality of polymeric chelant particles, each polymeric chelant particle comprising a plurality of polyamine polymer backbones and one or more chelants, and wherein at least 90% (such as at least 95% or at least 99%) of the plurality of polymeric chelant particles have a particle size of from 2 μm to 300 μm (e.g., as measured by laser diffraction).

The composition according to the present invention, wherein the polymeric chelant comprises a plurality of polymeric chelant particles, each polymeric chelant particle comprising a plurality of polyamine polymer backbones and one or more chelants, and wherein at least 90% (such as at least 95% or at least 99%) of the plurality of polymeric chelant particles have a particle size of from 4 μm to 200 μm (e.g., as measured by laser diffraction).

The composition according to the present invention, wherein the polymeric chelant comprises a plurality of polymeric chelant particles, each polymeric chelant particle comprising a plurality of polyamine polymer backbones and one or more chelants, and wherein at least 90% (such as at least 95% or at least 99%) of the plurality of polymeric chelant particles have a particle size of from 4 μm to 150 μm (e.g., as measured by laser diffraction).

The composition according to the present invention, wherein the polymeric chelant comprises a plurality of polymeric chelant particles, each polymeric chelant particle comprising a plurality of polyamine polymer backbones and one or more chelants, and wherein at least 90% (such as at least 95% or at least 99%) of the plurality of polymeric chelant particles have a particle size of from 5 μm to 100 μm (e.g., as measured by laser diffraction).

In one embodiment, the composition is formulated for injection.

In one embodiment, the composition is formulated for ingestion.

The composition according to the invention, wherein the polymeric chelant is a hydrogel.

In another aspect, the invention provides a method comprising administering to a subject a composition as described above (including any of the embodiments described herein), alone or in any combination.

In another aspect, the invention provides a method of removing a metal from a metal-containing medium, the method comprising (a) applying to a medium (1) a polymeric chelating agent comprising a plurality of polyamine polymer backbones and one or more chelating agents; (2) An agent selected from the group consisting of antacids, histamine H2-receptor antagonists, proton pump inhibitors, and combinations thereof, wherein one or more chelating agents are covalently coupled to one or more primary and/or secondary amines (e.g., one or more primary amines) of at least one of the plurality of polyamine polymer backbones, and wherein the plurality of polyamine polymer backbones are crosslinked with a plurality of crosslinking agents; (B) Incubating the polymeric chelant and the reagent in a medium comprising a metal to form a polymeric chelant-metal complex; (C) The polymer chelator-metal complex is removed from the medium. Embodiments of a method for removing metal from a metal-containing medium include one or any combination of the following.

A method for removing metal from a metal-containing medium, wherein a polymeric chelator and a reagent are applied to the medium separately.

A method for removing metals from a metal-containing medium, wherein a polymeric chelator and an agent are formulated into a composition as described above (including any embodiment described herein, alone or in any combination).

In another aspect, the invention provides a method of treating an iron overload disease in a subject, the method comprising administering to the subject an effective amount of (1) a polymeric chelator comprising a plurality of polyamine polymer backbones and one or more chelators; (2) An agent selected from the group consisting of antacids, histamine H2-receptor antagonists, proton pump inhibitors, and combinations thereof, wherein one or more chelating agents are covalently coupled to one or more primary and/or secondary amines (e.g., one or more primary amines) of at least one of the plurality of polyamine polymer backbones, and wherein the plurality of polyamine polymer backbones are crosslinked with a plurality of crosslinking agents. As used herein and as is well known in the art, "treating" a disease or "treating" various diseases and conditions is a method for achieving a beneficial or desired result (e.g., clinical result). Beneficial or desired results can include, but are not limited to, alleviation of one or more symptoms or conditions; the range of diseases, disorders or conditions is narrowed; the state of the disease, disorder or condition is stable (i.e., not worsening); delay or slowing of disease, disorder or progression of disease; improvement or alleviation of a disease, disorder, or condition; and remission (whether partial or total), whether detectable or undetectable. A disease, disorder, or condition is "alleviated" by which is meant that the extent of the disease, disorder, or condition and/or the time course of the adverse clinical manifestations are reduced and/or progressed is slowed or prolonged as compared to the extent or time course of untreated. As used herein, the term "effective dose" refers to a dose sufficient to achieve a beneficial or desired result (e.g., clinical result), and thus, an "effective dose" depends on the context in which it is used. As used herein, the term "subject" may be a human, non-human primate, or other mammal, such as, but not limited to, dogs, cats, horses, cows, pigs, goats, monkeys, rats, mice, and sheep. In some embodiments, the subject is a human. Embodiments of the method of treating iron overload disorders include one or any combination of the following.

A method of treating iron overload disorders, wherein a polymeric chelator and an agent are administered separately.

A method of treating iron overload disorders, wherein the polymeric chelant and agent are formulated into a composition as described above (including any of the embodiments described herein, alone or in any combination).

Drawings

Some specific exemplary embodiments of the present disclosure may be understood by referring in part to the following description and the accompanying drawings.

FIGS. 1A and 1B depict block diagrams of enterobacterins and polymeric chelators.

FIG. 2 depicts a graph of the iron binding capacity of various cross-linking agents at pH 2.0 buffer.

FIG. 3 depicts a graph of the iron binding capacity of various cross-linking agents at pH 3.0 buffer.

Fig. 4 depicts a graph of the iron binding capacity of various cross-linking agents at pH 4.0 buffer.

Fig. 5 depicts a graph of the iron binding capacity of various cross-linking agents at pH 5.0 buffer.

Fig. 6 depicts a graph of the iron binding capacity of various cross-linking agents at pH 6.5 buffer.

Fig. 7 depicts a graph showing the effect of buffer pH on iron binding capacity.

Fig. 8 depicts a graph of iron binding capacity at different crosslink densities. Fig. 9 depicts a graph of iron binding capacity at different crosslink densities.

Fig. 10 depicts a graph showing the effect of pH (CaCO ₃ content) on the iron binding capacity of a chelator having polyethylene glycol (PEG 1000) with a molecular weight of about 1000 daltons as a cross-linking agent.

Fig. 11 depicts a graph showing the effect of pH (NaHCO ₃ content) on the iron binding capacity of a chelator with PEG1000 as a crosslinker.

Fig. 12 depicts a graph showing the effect of pH (NaHCO ₃ content) on the iron binding capacity of a chelating agent with BAM as cross-linking agent.

Detailed Description

In general, the present disclosure includes novel compositions and systems for metal chelation. In some embodiments, the present disclosure provides compositions comprising a cross-linked polymer chelator and an agent. In some embodiments, the agent is an agent that neutralizes or reduces gastric acid production, such as an antacid, histamine H2-receptor, proton pump inhibitor, or combination. The crosslinked polymeric chelant may include a plurality of polymeric backbones coupled to one or more metal chelants, and the polymer may be crosslinked with a plurality of crosslinking agents. The system may include a plurality of polymer backbones and one or more metal chelators coupled together or otherwise linked to bind the nature of the polymer and the ability to chelate metals, wherein the polymer backbones are crosslinked with a plurality of crosslinking agents. In some embodiments, the plurality of crosslinking agents comprises a single crosslinking agent having a molecular weight of 200 daltons to 6000 daltons.

In some embodiments, the polymer backbone coupled to the one or more metal chelators may include any polyamine polymer, such as polyallylamine (PAAm), poly (N-vinylformamide) (PNVF), polyvinylamine (PVAm), poly (lysine) (PLL), polyethylenimine (PEI), and the like. The polymer may also include amino acids, and the polymer may include polypeptides and proteins.

In some embodiments, any polymer capable of coupling to a chelating agent, such as an iron chelating agent, may be used that can be used for chelation to bind the nature and chelating ability of the polymer. The polymer may be any type of linear, branched, etc., polymer, or soluble, insoluble, etc., wherein the polymer is further crosslinked with a plurality of crosslinking agents, such as a plurality of crosslinking agents comprising a single crosslinking agent having a molecular weight of about 200 daltons to about 6000 daltons. The polymer may comprise a polyamine having amine functional groups capable of participating in a reaction with a chelating agent. In some examples, the polymer may include polyamine polymers, such as PVAm and PAAm. PVAm and PAAm are polycationic hydrogels consisting of pendant reactive primary amine groups for conjugation to chelators. In some embodiments, the crosslinked PVAm hydrogel can be synthesized by hydrolyzing the precursor polymer PNVF in an alkaline medium. In some embodiments, crosslinked PAAm hydrogels can be synthesized by crosslinking precursor PAAm chains with multiple crosslinking agents, such as multiple crosslinking agents comprising a single crosslinking agent having a molecular weight of about 200 daltons to about 6000 daltons. Both hydrogels can exhibit high affinity and selectivity for iron at a pH similar to GI.

In some embodiments, the chelating agent coupled to the polymer may include 2, 3-dihydroxybenzoic acid (DHBA) and/or other iron chelating agents. DHBA acid is a fragment of the well-known natural iron chelator enterobacterin (Log k=52), a high affinity siderophore that can be used to obtain iron for microbial systems. FIG. 1A depicts a block diagram of enterobacterin. Chelating agents for other metals that may be coupled to the polymer may also be included.

In some embodiments, the chelating agent may be coupled to the polymer through a carboxyl group of the chelating agent. In some embodiments, the chelator may be coupled to the polymer through a peptide bond. In some embodiments, the chelating agent may include features for coupling with the polymer, for example, carboxyl groups (including activated carboxyl groups, such as N-hydroxysuccinimide (NHS) -activated carboxyl groups or activated carboxylate groups) of amines that may be coupled to the polymer through amide linkages. Other examples of features that may be included in the chelating agent for coupling with the polymer include, but are not limited to, epoxides, vinylamides, vinylsulfonamides, anhydrides, aldehydes, isocyanates, isothiocyanates, haloalkyl (e.g., chloroalkyl or bromoalkyl), haloaryl (e.g., fluorophenyl or chlorophenyl), carbonates, N-hydroxysuccinimide esters, imidoesters, haloaryl esters (e.g., fluorophenyl esters), 4-nitrophenyl esters, carbodiimides, sulfonyl chlorides, azides, alkyl esters, vinyl acyl groups, succinic anhydrides, and chloroformyl groups. In some embodiments, the feature may be any one of the following groups:

Other coupling agents may be included in the polymer and chelating agent system to produce a polymer chelating agent having the ability to chelate iron. Examples of iron chelating small molecules are disclosed in U.S. patent number 3,758,540. Examples of chelant schemes can be found in U.S. Pat. nos. 7,342,083, 5,702,696 and 5,487,888.

Other chelating agents will be understood by those skilled in the art. For example, but not limited to, other chelators to be tested may include commercially available chelators such as(Deferoxamine mesylate) and/or may contain moieties such as phenolates, enolates, ketones, aldehydes, carboxylates, phosphates and phosphonates, thiolates, sulfides and disulfides, hydroxamic acids and hydroxamates, amines, amides and nitrones. In some embodiments, the chelating agent may be deferoxamine, phytic acid, oxalic acid, polyglycerol, polyphenols, benzene-1, 2-diol, benzene-1, 2, 3-triol, 1, 10-phenanthroline or a derivative of N, N-bis (2-hydroxyphenyl) ethylenediamine-N, N' -diacetic acid, such as a derivative of the above groups that is derivatized to include any one of the features for coupling with the above polymers.

In some embodiments, the polymeric chelants are prepared by reacting the known iron chelator 2, 3-dihydroxybenzoic acid (DHBA) with a polyamine polymer. FIG. 1B depicts a block diagram of such a polymeric chelant formed by reacting a chelant with a polyamine polymer. Obviously, the polyamine polymer may be further crosslinked with a plurality of crosslinking agents, including individual crosslinking agents having a molecular weight of 200 daltons to 6000 daltons.

In some embodiments, the composition may be prepared as a solid or equilibrated in an aqueous solution as a solution or suspension. Polyamine conjugates have excellent binding affinity and selectivity for iron. In some embodiments, the polyamine polymer can comprise PVAm and PAAm. PVAm and PAAm are polycationic hydrogels consisting of reactive primary amine pendant groups for conjugation to DHBA. DHBA acid is a fragment of the well-known natural iron chelator enterobacterin (Log k=52), a high affinity siderophore that can be used to obtain iron for microbial systems. Crosslinked PVAm hydrogels can be synthesized by hydrolyzing the precursor polymer PNVF in an alkaline medium in the presence of multiple crosslinking agents (e.g., separate crosslinking agents having a molecular weight of 200 daltons to 6000 daltons). Crosslinked PAAm hydrogels can be synthesized by crosslinking precursor PAAm chains with a plurality of crosslinking agents, such as a plurality of crosslinking agents comprising a single crosslinking agent having a molecular weight of 200 daltons to 6000 daltons (e.g., 200 daltons, 400 daltons, 600 daltons, 1000 daltons, 2000 daltons, or 6000 daltons). At a pH similar to GI, both types of polymeric chelators can exhibit high affinity and selectivity for iron.

In embodiments, the polyamine polymer backbones each comprise polyallylamine or poly (lysine).

In some embodiments, the composition comprises an antacid. Those skilled in the art will appreciate that antacids neutralize acidity and may include CaCO ₃、NaHCO₃、MgCO₃、Mg(OH)₂、MgO、Al(OH)₃, dimethylsiloxane, and the like, including any other antacids known to those skilled in the art. In some embodiments, the composition comprises a histamine H2-receptor antagonist, such as cimetidine, famotidine, nizatidine, or ranitidine. In some embodiments, the composition comprises a proton pump inhibitor, such as omeprazole, esomeprazole, lansoprazole, rabeprazole, pantoprazole, dexlansoprazole. In some embodiments, the composition comprises a combination of an antacid and a histamine H2-receptor antagonist. In some embodiments, the composition comprises a combination of an antacid and a proton pump inhibitor (e.g., omeprazole and NaHCO ₃). In some embodiments, the composition comprises a combination of a histamine H2-receptor antagonist and a proton pump inhibitor. In some embodiments, the composition comprises a combination of an antacid, a histamine H2-receptor antagonist, and a proton pump inhibitor.

In embodiments, the plurality of crosslinking agents comprises bisacrylamide units.

In embodiments, the plurality of crosslinking agents each comprise polyethylene glycol. As used herein, "polyethylene glycol" or "PEG" refers to a group of the general formula- (OCH ₂CH₂) nO-where n is an integer (e.g., 2-150、2、3、4、5、5-10、10-20、20-30、30-40、50-60、60-70、70-80、80-90、90-100、100-110、110-120、120-130、130-140, or 140-150). In some embodiments, the molecular weight (Mn) of PEG is 200Da to 6000Da (e.g., 400Da to 2500Da, 800Da to 2200Da, 1000Da to 2000Da、200Da、400Da、600Da、800Da、1000Da、1200Da、1500Da、2000Da、2200Da、2500Da、3000Da、3500Da、4000Da、4500Da、5000Da、5500Da, or 6000 Da). PEG-based cross-linking agents are generally well known in the art and are commercially available.

PEG-based crosslinkers for amine PEGylation include reactive end groups including, but not limited to, carboxyl, epoxide, vinylamide, vinylsulfonamide, anhydride, aldehyde, isocyanate, isothiocyanate, haloalkyl (e.g., chloroalkyl or bromoalkyl), haloaryl (e.g., fluorophenyl or chlorophenyl), carbonate, N-hydroxysuccinimide ester, imidoester, haloaryl ester (e.g., fluorophenyl ester), 4-nitrophenyl ester, carbodiimide, sulfonyl chloride, acyl azide, alkyl esters, vinyl acyl, succinic anhydride, and chloroformyl. In embodiments, the plurality of crosslinking agents are derived from polyethylene glycol diacrylate units.

In some embodiments, the PEG-based crosslinker comprises two or more PEG chains linked by one or more linking groups. Molecules useful as linking groups include at least two functional groups (which may be the same or different) that can form covalent bonds with the reactive end groups of the respective PEG chains. Functional groups include, but are not limited to, amines, carboxyl groups, epoxides, vinylamides, vinylsulfonamides, anhydrides, aldehydes, isocyanates, isothiocyanates, haloalkyl groups (e.g., chloroalkyl or bromoalkyl groups), haloaryl groups (e.g., fluorophenyl or chlorophenyl groups), carbonates, N-hydroxysuccinimidyl esters, imidoesters, haloaryl esters (e.g., fluorophenyl esters), 4-nitrophenyl esters, carbodiimides, sulfonyl chlorides, acyl azides, alkyl esters, vinyl groups, vinyl acyl groups, succinic anhydrides, and chloroacyl groups. In some embodiments, the individual PEG chains each comprise two different reactive end groups, e.g., one for forming a conjugate bond with a linking group and one for forming a conjugate bond with an amine on the polyamine polymer backbone. Strategies for forming bonds between individual PEG chains are well known in the art.

In embodiments, the plurality of crosslinking agents are derived from polyethylene glycol glycidyl ether units.

In embodiments, the plurality of crosslinking agents comprises a single hydrophilic crosslinking agent. In some embodiments, the hydrophilic cross-linking agent is a compound having a water solubility greater than N, N' -methylenebisacrylamide at 20 ℃. In some embodiments, the hydrophilic cross-linking agent is a compound having a water solubility greater than 20g/L (e.g., at least 50g/L, at least 100g/L, at least 150g/L, at least 200g/L, at least 250g/L, at least 300g/L, at least 500g/L, at least 550g/L, at least 600g/L, or at least 650 g/L) at 20 ℃.

In embodiments, the plurality of cross-linking agents comprises individual cross-linking agents, preferably having a molecular weight of 400 daltons to 2500 daltons, or 400 to 1200 daltons, or 400 to 1000 daltons, more preferably having a molecular weight of 800 daltons to 2200 daltons, or 800 daltons to about 2000 daltons.

The composition according to the invention, wherein the plurality of crosslinking agents crosslink to the polymer chain at a density of about 0.01% to 10% (e.g. 0.01% to 7.5%, 0.01% to 5%, 0.01% to 2%, 0.05% to 7.5%, 0.05% to 5%, 0.05% to 2%, or 0.01%, 0.05%, 0.1%, 0.2%, 0.5%, 0.75%, 1%, 2%, 5%, 7.5% or 10%) by mole of the total amine, preferably at a density of less than or equal to 1% by mole of the total amine, e.g. at a density of 0.01% to 1% by mole of the total amine.

Notably, the crosslinked polymer wherein the crosslinking agent has a molecular weight of 400 daltons to 1200 daltons and a crosslinking density of 0.01% to 2% by mole of total amine; a crosslinked polymer wherein the crosslinking agent has a molecular weight of 400 daltons to 1200 daltons and a crosslinking density of 0.01% to 5% based on total amine mole ratio; a crosslinked polymer wherein the crosslinking agent has a molecular weight of 800 daltons to 2200 daltons and a crosslinking density of 0.01% to 2% based on total amine mole ratio; a crosslinked polymer wherein the crosslinking agent has a molecular weight of 800 daltons to 2200 daltons and a crosslinking density of 0.01% to 5% based on total amine mole ratio.

In some embodiments, conjugation of DHBA may promote iron binding affinity and iron selectivity of the final hydrogel conjugate, cross-linked polymer chelator. In some embodiments, primary amine groups in both polymers may be used as conjugation sites. Non-degradable PVAm and PAAm hydrogels conjugated with DHBA are useful as oral therapeutics for iron overload disease patients. Such therapeutic agents may selectively bind iron and remove it from the GI before it is absorbed into the blood stream.

In some embodiments, the present disclosure provides a composition comprising a plurality of polymeric chelant particles, wherein at least 90% of the particles have a particle size of 300 μm or less, such as 300 μm to 2 μm, 200 μm to 4 μm, 150 μm to 4 μm, 100 μm to 5 μm, or 70 μm to 18 μm, 45 μm to 18 μm, or 45 μm or less, such as a particle size of 300μm、275μm、250μm、225μm、200μm、175μm、150μm、125μm、100μm、75μm、65μm、55μm、50μm、45μm、40μm、35μm、30μm、25μm、20μm、18μm、15μm、12.5μm、10μm、7.5μm、5μm、4μm、3μm、2μm or 1 μm. In some embodiments, the size of the polymeric chelant particles is determined using laser diffraction, for example using Malvern Masterizer. In embodiments, the size of the polymeric chelator particles measured by laser diffraction includes a d10 of 100 μm or less, such as a d10 of 100 μm, 75 μm, 65 μm, 55 μm, 50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 25 μm, 20 μm, 18 μm, 15 μm, 12.5 μm, 10 μm, 7.5 μm, 5 μm, 4 μm, 3 μm, 2 μm, or 1 μm. In embodiments, the size of the polymeric chelant particles as measured by laser diffraction includes a d50 of 150 μm or less, such as a d50 of 150μm、125μm、100μm、75μm、65μm、55μm、50μm、45μm、40μm、35μm、30μm、25μm、20μm、18μm、15μm、12.5μm、10μm、7.5μm、5μm、4μm、3μm、2μm or 1 μm. In embodiments, the size of the polymeric chelant particles as measured by laser diffraction includes a d90 of 250 μm or less, such as a d90 of 250μm、225μm、200μm、175μm、150μm、125μm、100μm、75μm、65μm、55μm、50μm、45μm、40μm、35μm、30μm、25μm、20μm、18μm、15μm、12.5μm、10μm、7.5μm、5μm、4μm、3μm、2μm、 or 1 μm. In other embodiments, thioglycolic acid (TGA) combined with siderophore portion DHBA can be introduced onto PAAm and PVAm to form a polymeric chelator.

In one aspect, the present disclosure provides a composition comprising a DHBA-conjugated monomer. The monomer may be coupled to DHBA by a monomer having an amine group that reacts with and couples to the carboxyl group of DHBA. Monomers having DHBA may be used in compositions similar to those described for polymers coupled to DHBA. Examples of suitable monomers include any monomer capable of coupling to a chelator, such as an iron chelator. The monomer may be any type of monomer. The monomer may include an amine having an amine functional group capable of participating in a reaction with the chelating agent. In some embodiments, the monomer may comprise an amine monomer.

In some embodiments, the polymeric chelants may be prepared by reacting DHBA with a polyamine polymer to form amide linkages and further cross-linking. polyamine-DHBA chelating polymers have excellent binding affinity and selectivity for iron.

In some embodiments, the polyamine polymer is PVAm or PAAm. Both PVAm and PAAm are polycationic hydrogels with pendant reactive primary amine groups that can be coupled to 2, 3-DHBA. Crosslinked PVAm hydrogels can be synthesized by hydrolyzing the precursor polymer PNVF in an alkaline medium. Crosslinked PAAm hydrogels can be synthesized by crosslinking the precursor PAAm chains.

In some embodiments, the synthesized crosslinked polymer may be washed according to a washing procedure. The wash procedure may include the application of one or more wash solutions. In some embodiments, the wash solution has one or more bases. One or more bases are capable of quenching the synthesis reaction. In some embodiments, the one or more bases may include sodium hydroxide, potassium hydroxide, calcium hydroxide, and the like. In some embodiments, the alkaline concentration of the wash liquor in the aqueous solution may be from 0.01 to 1.0M (e.g., 0.01M、0.05M、0.1M、0.15M、0.2M、0.25M、0.3M、0.35M、0.4M、0.45M、0.5M、0.55M、0.6M、0.65M、0.7M、0.75M、0.8M、0.85M、0.9M、0.95M or 1M). Or in some embodiments, the wash solution may be deionized water.

In some embodiments, the washing procedure can include washing the synthesized crosslinked polymer with a first washing solution having a base, and then washing with a second washing solution of deionized water. In some embodiments, the first scrubbing solution or the second scrubbing solution may be applied under the protection of an inert gas such as nitrogen, argon, helium, or the like. For example, the first wash solution or the second wash solution may be applied under nitrogen protection.

The composition may be formulated as a solid, gel, paste or liquid, for example equilibrated in aqueous solution as a solution or suspension.

In some embodiments, the composition may be administered orally to treat, inhibit or prevent iron overload. Thus, the composition may be included in an oral therapeutic agent for patients with iron overload disorders. The composition may selectively bind iron and remove it from the GI before it is absorbed into the blood stream. The composition may be deposited in tissue or applied systemically to sequester iron.

The composition can be used as a metal chelator to remove metals from a variety of materials and can be widely used in different fields. Polycations have been used in industrial applications such as water treatment and ion exchange resins (for separation and purification purposes). The high affinity and selectivity for iron provides important features for the application of these gels.

The cross-linked polymer chelator may be a highly efficient metal (e.g., iron) chelator that selectively binds metals in the GI and prevents the metals from being absorbed into the blood stream. The chelated metal may be discharged from the GI as waste.

In some embodiments, the present disclosure provides compositions (e.g., any of the compositions disclosed herein) that can be injected or ingested. In some embodiments, the dosage form is designed to facilitate patient compliance. The gel form may retain the chelator in the gastrointestinal tract to enable self-administration of the compound as desired and to alleviate systemic side effects plagued by current iron chelators. The injectable composition may improve safety compared to DFO, and may optimize polymer molecular weight, including molecular weight and crosslink density of the crosslinking agent, to extend circulation half-life.

In one embodiment, the polymeric chelant may be configured to include a water-soluble polymer or monomer. The composition may be configured for administration by injection and is relatively non-toxic or has reduced toxicity. In one embodiment, the polymeric chelant may be configured to have a molecular weight suitable for injection. In another embodiment, the polymeric chelant may be configured to have a molecular weight suitable for ingestion. In addition, compositions with polymeric chelants may be formulated for inhalation or topical application.

In one embodiment, the composition may be ingested and metal uptake may be prevented by chelating the metal. The composition may include a crosslinked polymer configured for uptake. In some embodiments, the composition may be ingested and configured to be absorbed from the intestine such that the chelator may chelate metals that have been absorbed into the body.

In some embodiments, the polymeric chelators disclosed herein can more accurately mimic the enterobacterin side chains shown. Crosslinked polymeric chelants that mimic the structure of siderophores can be viewed as an ideal parenterally administered iron chelator. The plasma half-life of these polymer formulations can be optimized according to the initial molecular weight of the polymer. Furthermore, the toxic side effects of these polymeric chelators can be significantly reduced, as they consist of polypeptide units. The polymeric form of the siderophore mimetic has several therapeutic advantages. These compounds can prevent bacterial absorption of iron. In addition, cross-linked polymer chelators can localize compounds to the GI (oral gel material) and/or extend circulation half-life by increasing molecular weight (injectable material).

In certain embodiments, the polymeric chelant in crosslinked form is not absorbed upon oral administration. These materials can exhibit rapid iron binding with high affinity and selectivity. In some embodiments, the iron-binding pM values of the materials disclosed herein are at least ten times greater than any existing therapeutic chelator. The design of these polymers can alleviate the systemic side effects and toxicity of current drugs. In some embodiments, the polymeric chelator selectively and effectively binds iron in the GI if administered orally, or selectively and effectively binds iron from the blood stream if administered parenterally.

In one embodiment, the crosslinked polymeric chelants may be incorporated into textiles, fabrics, absorbent members, gauze, wipes, bandages, and the like. Further applications of the cross-linked polymeric chelants are useful for metal chelation in a variety of consumer products and processes. For example, polymeric chelants may be used in oil well treatments, such as those used to scale removal or inhibit scale formation.

In order to facilitate a better understanding of the present invention, exemplary embodiments are given below. The following examples should not be construed as limiting or restricting the full scope of the invention.

Examples

Synthesis and characterization.

Poly (allylamine hydrochloride) (PAAm) having an average molecular weight of 15kDa and analytical grade reagent N, N' -methylenebisacrylamide (BAM) were obtained from Sigma-Aldrich and used without further modification. 2, 3-dihydroxybenzoic acid, N, N, N-triethylamine, dimethylformamide (DMF), potassium phosphate and all metal chlorides were purchased from FISHER SCIENTIFIC and used as such. N- (3-dimethylaminopropyl) -N' -ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) were purchased from Thermo Scientific and used without further modification. Polyethylene glycol glycidyl ether was purchased from Polysciences, inc. Deionized water (DI) was obtained from Barnstead EasyPure water purifiers.

The poly (allylamine hydrochloride) is crosslinked with several polyethylene glycol glycidyl ether units of different average molecular weights. The average molecular weights of the cross-linking agents were 200, 400, 600, 1000, 2000 and 6000 daltons (see fig. 2-6).

The reaction was carried out in water to provide a crosslink density of 1.0% by mole of total amine groups. Although crosslinking is accomplished by linking primary amine groups, there are still a significant number of reactive amino sites available for further modification of PAAm hydrogels. DHBA was covalently linked to PAAm hydrogels by EDC/NHS conjugation chemistry.

NHS-activated DHBA.

A solution of DHBA (770 mg,5 mmol) and NHS (690 mg,6 mmol) in 5mL DMF was mixed with a solution of EDC (1200 mg,6.2 mmol) in 5mL DMF. The mixture was stirred at room temperature for 8h and used for the next reaction step without any purification.

Preparation of DHBA modified hydrogels.

PAAm crosslinking and DHBA conjugation were performed in a one-step reaction. Briefly, a 15% w/w PAAm (15 kDa) solution containing a predetermined dose of BMA (total amine mole ratio 1%) was prepared in a H ₂ O/DMF (50/50 v/v) mixture. Then, NHS-activated DHBA solution was added to the reaction mixture, with a final DHBA/amine molar ratio of 25%, and sonicated until a clear solution (about 2 minutes) was obtained. Triethylamine (TEA) was then added to the solution and mixed thoroughly, and the solution was incubated at room temperature for 48h. The resulting crosslinked polymer was then washed with 0.1M sodium hydroxide under nitrogen, followed by deionized water for several days. DHBA modified PAAm hydrogels were lyophilized and ground with a mortar and pestle for 5min to a fine powder.

Iron binding capacity can be measured at different pH values and different isotherm models can be used to fit the data.

The results of the iron binding capacities at pH 2.0, 3.0, 4.0, 5.0 and 6.5 are summarized in FIGS. 2-6, respectively, and compared to polymers crosslinked with BAM. At low pH, the absorption of metal ions is relatively low. Increasing the pH increases the absorption value of the metal ions. At a pH of 2.0, all crosslinked polymers showed similar iron binding capacities, ranging from about 16mg/g to 16mg/g. The iron binding capacity increased at pH 3.0 and 4.0, above which the iron binding capacity stabilized at about 90mg/g to 100mg/g. In general, as shown in FIG. 7, the binding capacity increases with an increase in the average molecular weight of the crosslinking agent, and thus the length of the crosslinking agent increases. When equilibrated in ferric iron solutions, they exhibit almost immediate iron absorbance. The crosslinked chelating polymer is a hydrogel that exhibits high affinity and selectivity for iron at a pH similar to GI, and the time required for the swelling reaction of the polymer to equilibrate for the gel varies at different pH.

Fig. 8 shows the iron binding capacity of a crosslinked polymer comprising a crosslinking agent having an average molecular weight of about 400 daltons and a crosslink density of about 0.05% to about 1% at a pH of 5.0. All of these crosslinked polymers exhibit an iron binding capacity of 90mg/g to 98mg/g at pH 5.0. Polymers with a crosslink density of 0.05% to 0.5% exhibit an iron binding capacity of higher than 96 mg/g. The polymer with a crosslink density of 1% exhibited a decrease in iron binding capacity, indicating that shorter crosslinkers were expected to have lower crosslink densities to provide better iron binding.

Fig. 9 shows the iron binding capacity of a crosslinked polymer comprising a crosslinking agent having an average molecular weight of about 2000 daltons and a crosslink density of about 0.05% to about 1% at a pH of 5.0. All of these crosslinked polymers exhibit iron binding capacities of about 98mg/g to 99mg/g or more at pH 5.0. The decrease in iron binding capacity was less severe for the longer cross-linking density of the cross-linker at 1% polymer.

FIGS. 10-12 show the effect of an added antacid such as calcium carbonate or sodium bicarbonate on iron binding capacity. Fig. 10 and 11 depict the iron binding capacity of chelators with PEG1000 crosslinkers added either calcium carbonate (fig. 10) or sodium bicarbonate (fig. 11). Fig. 12 depicts the iron binding capacity of chelators with bis-acrylamide (BAM) crosslinker added sodium bicarbonate. When tested in a buffer at pH 2.0 (similar to the pH of gastric juice), the iron binding capacity increased with increasing antacid level. This indicates that formulating or applying the crosslinked polymer with an antacid is advantageous for improving the iron binding capacity.

Iron chelators for both oral and parenteral administration must have high selectivity and affinity for iron. Furthermore, parenterally administered iron chelators should be non-toxic and have a relatively long plasma half-life.

Isotherms for the iron and ferrous solutions can be obtained separately at different pH values and fitted using well known solute adsorption models, such as the friendlich, langmuir or thomson adsorption models (Temkin).

Different isotherm models were used to determine how the metal molecules were distributed between the liquid phase hydrogel and the solid hydrogel phase when the adsorption process reached equilibrium. Langmuir, freundlich and Temkin isotherm models were applied to the data. The adsorption parameters of iron ions and ferrous ions at different pH values are calculated. The accuracy of the isotherm model can be assessed by a linear correlation coefficient (R ²) value.

Langmuir adsorption isotherms.

The langmuir adsorption isotherms assume that a monolayer is adsorbed on a surface containing a limited number of adsorption sites. The linear form of the langmuir adsorption isotherm is as follows:

Where C _e is the equilibrium concentration of metal ions (mg/L), q _e is the amount of metal ions (mg/g) adsorbed per unit mass of hydrogel, and K _L and q _max are the Langmuir constants associated with adsorption/desorption energy and adsorption capacity, respectively. When C _e/q_e is plotted against C _e, a straight line with a slope of 1/q _max is obtained. The langmuir constants K _L and q _max are calculated from equation (2).

Friedrichs adsorption isotherms.

The friedrichs adsorption isotherm assumes a non-uniform surface energy, where the energy term in the langmuir equation varies as a function of surface coverage. The linear form of the friedrichs adsorption isotherm is given by the following equation:

Where C _e is the equilibrium concentration of metal ions (mg/L), q _e is the amount of metal ions adsorbed per unit mass of hydrogel (mg/g), K _F (mg/g (L/mg) 1/n) and n is the Friedel-crafts constant, where n represents the degree of advantage of the adsorption process. lnq _e and lnC _e show a straight line with a slope of 1/n. The friedrichs constants K _F and n can also be calculated.

Adsorption isotherms of the Amgold.

Temkin-Pyzhev consider the effect of indirect adsorbate/adsorbate interactions on adsorption isotherms. The heat of adsorption of all molecules in the layer will decrease linearly with coverage due to the adsorbate/adsorbent interaction. The isothermal adsorption of the Amgold was used as follows:

The relationship between q _e and lnC _e produces a straight line.

Swelling studies.

The swelling kinetics of PAAm and PAAm/DHBA can be studied to determine the time to reach equilibrium. Hydrogel swelling increases with time; however, it will eventually tend to stabilize and thus the equilibrium swelling percentage can be calculated. The cross-linker concentration was varied and the swelling behaviour of the hydrogels was determined.

High throughput cell viability assays can be accomplished using standard procedures. Cytotoxicity of the polymer can be achieved by CellTiterAque cell proliferation assay kit (Promega). HUVEC cells may be incubated with the polymer for about 24 hours. The medium can then be removed and replaced with a mixture of 100 μl fresh medium and 20 μl MTS reagent solution. Cells can be incubated in a 5% CO ₂ incubator at 37 ℃ for 3 hours. The absorbance of each well can then be measured at 490nm using a microtiter plate reader (microtiter PLATE READER) (spectromax, M25, molecular Devices corp.) to determine relative cell viability. Similar studies can be performed on polymer gels for oral delivery using Caco-2 cells (colonic epithelium).

Female Sprague-Dawley rats of about 6 weeks of age can be used to evaluate the effect of treatment on iron load. After the animals reach equilibrium for diet and environment under KU, the initial iron levels in the rat blood can be measured before starting the experiment.

The animals may be fed a 25mg/kg gel-containing diet for 4 days, which may provide sufficient time to clear the untreated intestinal contents. Urine, faeces and blood samples of each animal may then be collected on days 5 and 10. Animals receiving injection of the chelator Deferoxamine (DFO), siMiP-01, or SiMiP-02 may receive subcutaneous injections (40 mg/kg, 1 every 2 days) over a period of 10 days (e.g., injections on days 2, 4, 6, etc.). High molecular weight polymers (> 25 kDa) may not be well absorbed; thus, if a larger polymer is considered a better iron chelator, tail vein injection may be used instead of subcutaneous injection. The iron content in blood, faeces and urine may be measured using ICP-MS. The pain condition of the animal can be continuously monitored and blood samples of animals receiving the chelating agent injection can be analyzed for aspartate aminotransferase, alanine transamidase, total bilirubin, alkaline phosphatase and/or urea nitrogen and serum creatinine to monitor liver and kidney function, respectively. Experimental protocols may involve healthy animals and moderate doses of iron; thus, animal health is not expected to be compromised. SiMiG-03 and SiMiP-03 may also be tested if another suitable polymer is identified.

Quantification of amine functionality.

Primary amine groups can be quantified by potentiometric titration. After grinding to a powder, 40mg of crosslinked polymer was suspended in 35mL of 0.2M aqueous KCl. Next, 140. Mu.L of 8M KOH aqueous solution was added to the polymer suspension to raise the pH to about 12. The suspension was titrated with standard 0.1M HCl. HCl was added until the pH in the polymer suspension was about 2.5. Free amine groups were quantified from the potential data according to the reported procedure.

Determination of polymer-iron stability constant.

The stability constant or "binding coefficient" of a gel chelator can be measured using a conventional ligand competition assay. Cross-linked polymer chelators with water-soluble chelators (ethylenediamine tetraacetic acid: EDTA) can be used to determine the stability constant of the iron-ligand complex of the polymer. Briefly, 2mL of 5mM FeCl ₃ solution and 21.5mL of PBS and a known mass of gel can be added to 1.5mL of 10 mM EDTA solution. The mixture may be spun at 20 ℃ for 3 days and the concentration of the soluble iron complex may be determined by inductively coupled plasma mass spectrometry (ICP-MS). The stability constant of the gel can be determined according to procedures reported in the literature. Stability constants can also be determined by potentiometric titration to confirm the results.

Selectivity studies.

The selectivity of PAAm-DHBA for iron in the presence of various heavy metals such as copper, zinc, manganese, calcium and potassium can be studied. A metal solution (10 mL) containing all the metal components was prepared. The upper allowable intake limit of each metal is used as the initial concentration in the solution. These concentrations were selected based on recommended daily intake (RDA) data in the united states, which relates to the daily meal intake of these metal ions present in a normal meal. After adding a known mass of cross-linked polymer chelating agent as xerogel, the solution mixture was adjusted to pH 2.5 and kept at room temperature for 2 hours.

And (5) metal analysis.

Single and multi-element analysis of the samples can be quantified by inductively coupled plasma emission spectrometry (ICP-OES) (Optima 2000dv, perkinelmer, usa) equipped with an as93+ autosampler (PERKINELMER, USA). A cross-flow atomizer and Scott atomizer chamber were used. The RF power was 1300W, and the nebulizer and auxiliary flow were 0.8L/min and 0.2L/min, respectively. The sample flow rate was set at 1.5mL/min. ICP-OES data were processed using Winlab (ver.3.0, PERKINELMER, USA).

EDC/NHS coupling chemistry can be used to react the free amine side chains of hydrogels with the carboxy terminus of DHBA. Since the concentration of DHBA hydroxyl groups may be critical to enhance iron binding, the selection of the appropriate PAAm-DHBA ratio is important to obtain hydrogels with high iron affinity.

Conditional stability constant of iron (III) -hydrogels.

Ligand competition methods are widely used to determine the stability constants of soluble iron (III) -ligand complexes and crosslinked polymer chelators. A decrease in DHBA concentration results in a decrease in the conditional stability constant. As the concentration of functional groups in the hydrogel decreases, the binding capacity of the hydrogel also decreases. The chelating properties of the polymeric chelants have been shown to be affected by steric hindrance between the ligand and the polymer matrix, but in the case of cross-linked PAAm-DHBA hydrogels, the impact of the polymer backbone during iron chelation may be small.

Selectivity of PAAm-DHBA hydrogels.

Since PAAm-DHBA hydrogels have high affinity for iron (III), it is expected that crosslinked PAAm-DHBA hydrogels may also have higher selectivity for iron (III) than other metal ions. Copper (II), zinc (II) and manganese (II) are all present in biological tissues and foods. Since these three metals are vital to life, it is important that the hydrogels designed for this study have much lower affinity for this group of divalent cations.

Among the various crosslinking agents: synthesis at polymer ratios helps to determine a range of swelling indices acceptable for biomedical applications while maintaining acceptable reaction yields. Product according to research report and FDA approvalThese values are known to provide sufficient mechanical integrity and chemical stability after oral administration.

Swelling studies.

The swelling behaviour of hydrogels can be studied using a buffer solution (sodium hydroxide as buffer) with a fixed ionic strength (0.5M). A buffer solution with a known ionic strength was prepared using a historical protocol. A known weight of the dried sample was placed in a solution at room temperature at a defined pH. Samples were taken from the solution after equilibrium was reached. The Swelling Index (SI) was calculated using the following formula:

Wherein W _s is the weight of the swollen hydrogel in the equilibrium state and W _d is the weight of the dried hydrogel.

Binding kinetics.

The determination of metal adsorption kinetics helps elucidate the reactivity of cross-linked polymeric chelators and evaluate their potential in chemical and biomedical applications. In the presence of a known mass of dry hydrogel, a known initial concentration of metal solution (2 mg/mL, feCl ₃) can be used to monitor the kinetics of metal binding.

Ferric chloride and ferrous chloride solutions (0.25, 0.5, 1,2, 2.5 mg/mL) of known concentrations can be prepared. Binding experiments can be performed by taking 20mL of the metal solution in a 125mL volumetric flask and adjusting the solution to the desired pH while maintaining the iron concentration. Next, a known mass of crosslinked hydrogel was added to the mixture and held at room temperature for 2 hours or until equilibrium was reached. The solution was then filtered and the filtrate analyzed for metal concentration.

Rapid adsorption behaviour is important in biomedical applications, especially for the treatment of acute metal poisoning. To derive the rate constants and binding capacities, the kinetic data can be modeled using a pseudo-first-order (LAGERGREN model) and a pseudo-second-order (Ho model) kinetic model, which are expressed in their linear form as:

wherein k ₁ (L/min) and k ₂ (g/mg min) are a pseudo first order rate constant and a pseudo second order rate constant, respectively.

Here, C _H is the concentration of the hydrogel.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. All references cited herein are incorporated by reference in their entirety.

Instead of synthetic, NHS activated DHBA.

A solution of DHBA (0.5 kg,3.27 mol), NHS (0.75 kg,6.54 mol) in 1.7L DMF was mixed with a suspension of EDC (0.56 kg,2.9 mmol) in 1.7L DMF. The mixture was stirred until the reaction was complete and used for the next reaction step.

Preparation of DHBA modified hydrogels.

PAAm having an average molecular weight of 15kDa-18kDa (2.5 kg of 50% aqueous solution, 13.1 mol) was further diluted with 1.98kg of water, followed by addition of NHS-activated DHBA solution, followed by addition of 0.125kg of water, followed by addition of BMA (0.002kg, 0.01 mol) solution in DMF/water (0.25L each) and triethylamine (2.35 kg,23.2 mol). The reaction mixture was stirred for 24 hours. The resulting crosslinked polymer was then washed with 0.1M sodium hydroxide, acetonitrile/water, isopropanol and isopropanol/water. The resulting polymer is then ground and sieved to achieve the target particle size distribution.

Claims (48)

1.A composition comprising:

(i) A polymeric chelant comprising a plurality of polyamine polymer backbones and one or more chelants; and

(Ii) An agent selected from the group consisting of antacids, histamine H2-receptor antagonists, proton pump inhibitors, and combinations thereof,

Wherein the one or more chelating agents are covalently coupled to one or more primary and/or secondary amines of at least one of the plurality of polyamine polymer backbones; and

Wherein the plurality of polyamine polymer backbones are crosslinked with a plurality of crosslinking agents.

2. The composition of claim 1, wherein each of the plurality of polyamine polymers comprises a polyamine polymer having a weight average molecular weight of 1-50 kDa.

3. The composition of claim 1 or 2, wherein each of the polyamine polymer backbones comprises a monomer unit having the structure:

Wherein the method comprises the steps of

L ₁ is C ₁-C₆ alkylene;

L ₂ is a bond or C ₁-C₆ alkylene; and

R is H or C (O) R ', wherein R' is H, C ₁-C₆ alkyl or C ₆-C₁₂ aryl.

4. The composition of any of claims 1-3, wherein each of the plurality of polyamine polymer backbones comprises polyallylamine.

5. The composition of any of claims 1-3, wherein the plurality of polyamine polymer backbones comprise poly (lysine).

6. The composition of any one of claims 1-5, wherein the agent is an antacid.

7. The composition of claim 6, wherein the antacid is CaCO ₃、NaHCO₃、MgCO₃、Mg(OH)₂、MgO、Al(OH)₃ or simethicone.

8. The composition of any of claims 1-7, wherein each of the plurality of cross-linking agents independently has the structure:

Wherein the method comprises the steps of

R ₁ and R ₂ are independently selected from:

R' is H or C ₁-C₆ alkyl;

n is 0, 1 or 2; and

L ₃ is a bond, C ₁-C₆ alkylene, C ₁-C₆ heteroalkylene, C ₃-C₈ cycloalkylene, C ₆-C₁₄ arylene, or a 5-or 6-membered heterocyclylene or polyethylene glycol.

9. The composition of claim 8, wherein each of the plurality of cross-linking agents has the structure:

10. the composition of claim 9, wherein the polymeric chelant comprises a plurality of groups, each having the structure:

11. The composition of claim 9 or 10, wherein L ₃ is methylene.

12. The composition of claim 8, wherein each of the plurality of cross-linking agents has the structure:

13. the composition of claim 12, wherein the polymeric chelant comprises a plurality of groups, each having the structure:

14. The composition of any one of claims 8-10, 12, and 13, wherein L ₃ is polyethylene glycol.

15. The composition of claim 14, wherein the polyethylene glycol has a number average molecular weight of 200 daltons to 6000 daltons.

16. The composition of claim 15, wherein the polyethylene glycol has a number average molecular weight of 400 daltons to 2500 daltons.

17. The composition of claim 16, wherein the polyethylene glycol has a number average molecular weight of from 800 daltons to 2200 daltons.

18. The composition of any of claims 1-7, wherein each of the plurality of cross-linking agents is selected from the group consisting of:

19. the composition of any one of claims 1-7, wherein each of the plurality of cross-linking agents is a hydrophilic cross-linking agent.

20. The composition of any one of claims 1-7 and 19, wherein the plurality of cross-linking agents comprises a single cross-linking agent having a number average molecular weight of 200 daltons to 6000 daltons.

21. The composition of claim 20, wherein the plurality of crosslinking agents comprises individual crosslinking agents having a number average molecular weight of 400 daltons to 2500 daltons.

22. The composition of claim 21, wherein the plurality of crosslinking agents comprises individual crosslinking agents having a number average molecular weight of 800 daltons to 2200 daltons.

23. The composition of any one of claims 1-23, wherein the plurality of crosslinking agents crosslink to the polyamine polymer backbone at a density of 0.01% to 10% based on the molar ratio of total amine in the polyamine polymer backbone.

24. The composition of claim 23, wherein the plurality of crosslinking agents crosslink to the polyamine polymer backbone at a density of less than or equal to 1% based on the molar ratio of total amine in the polyamine polymer backbone.

25. The composition of any one of claims 1-24, wherein the one or more chelating agents each comprise a phenyl group substituted with at least two hydroxyl groups.

26. The composition of claim 25, wherein the one or more chelating agents each comprise 2, 3-dihydroxybenzoic acid.

27. The composition of claim 26, wherein the polymeric chelant comprises a plurality of groups, each having the structure:

28. The composition of any one of claims 1-24, wherein the one or more chelators each comprise a derivative of a metal chelator moiety.

29. The composition of claim 28, wherein the one or more chelating agents each comprise a derivative of deferoxamine, phytic acid, oxalic acid, polyglycerol, polyphenols, benzene-1, 2-diol, benzene-1, 2, 3-triol, 1, 10-phenanthroline or N, N-bis (2-hydroxyphenyl) ethylenediamine-N, N' -diacetic acid.

30. The composition of any one of claims 1-24, wherein the one or more chelating agents are capable of chelating heavy metals.

31. The composition of claim 30, wherein the one or more chelating agents are capable of chelating aluminum, arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, or a combination thereof.

32. The composition of claim 31, wherein the one or more chelating agents are capable of chelating iron.

33. The composition of any one of claims 1-32, wherein the one or more chelating agents are coupled to 5-30% of the amines on the plurality of polyamine polymer backbones.

34. The composition of any one of claims 1-33, wherein the polymeric chelant comprises a plurality of polymeric chelant particles, each polymeric chelant particle comprising the plurality of polyamine polymer backbones and the one or more chelants.

35. The composition of claim 34, wherein at least 90% of the plurality of polymeric chelant particles have a particle size of 300 μιη or less.

36. The composition of claim 36, wherein at least 90% of the plurality of polymeric chelant particles have a particle size of 2 μιη to 300 μιη.

37. The composition of claim 36, wherein at least 90% of the plurality of polymeric chelant particles have a particle size of 4 μιη to 200 μιη.

38. The composition of claim 36, wherein at least 90% of the plurality of polymeric chelant particles have a particle size of 4 μιη to 150 μιη.

39. The composition of claim 36, wherein at least 90% of the plurality of polymeric chelant particles have a particle size of 5 μιη to 100 μιη.

40. The composition of claim 36, wherein at least 90% of the plurality of polymeric chelant particles have a particle size of 18 μιη to 70 μιη.

41. The composition of any one of claims 1-40, wherein the composition is injectable.

42. The composition of any one of claims 1-40, wherein the composition is ingestible.

43. The composition of any one of claims 1-42, wherein the polymeric chelator is a hydrogel.

44. A method comprising administering to a subject the composition of any one of claims 1-43.

45. A method of removing metal from a metal-containing medium, the method comprising:

(A) Applying to the medium:

(1) A polymeric chelant formed from a plurality of polyamine polymer backbones, a plurality of cross-linking agents, and one or more chelants; and

(2) A therapeutic agent selected from the group consisting of antacids, histamine H2-receptor antagonists, proton pump inhibitors, and combinations thereof,

Wherein the one or more chelating agents are covalently coupled to one or more primary and/or secondary amines of at least one of the plurality of polyamine polymer backbones through one or more amide linkages; and

Wherein the plurality of polyamine polymer backbones are crosslinked with the plurality of crosslinking agents;

(B) Incubating a polymeric chelator and a therapeutic agent in the medium containing the metal to form a polymeric chelator-metal complex; and

(C) Removing the polymeric chelant-metal complex from the culture medium.

46. A method of treating an iron overload disease in a subject, the method comprising administering to the subject an effective dose of:

(1) A polymeric chelant formed from a plurality of polyamine polymer backbones, a plurality of cross-linking agents, and one or more chelants; and

(2) An agent selected from the group consisting of antacids, histamine H2-receptor antagonists, proton pump inhibitors, and combinations thereof,

Wherein the one or more chelating agents are covalently coupled to one or more primary and/or secondary amines of at least one of the plurality of polyamine polymer backbones; and

Wherein the plurality of polyamine polymer backbones are crosslinked with the plurality of crosslinking agents.

47. The method of claim 45 or 46, wherein the polymeric chelant and the agent are administered separately.

48. The method of claim 45 or 47, wherein the polymeric chelant and the agent are formulated into a composition according to any one of claims 1-43.