Patent Application
20090287072
Blood-contacting and implantable medical devices such as vascular grafts, intravascular catheters, coronary artery and vascular stents, insulation materials for electrical leads of pacemakers and defibrillators, extracorporeal bypass circuits, and oxygenators, etc. are manufactured from many different materials. The incompatibility of these materials with human blood and tissue may cause serious complications in patients, and ultimately functional device failure. Implantation of such devices into blood vessels may cause damage to the endothelial layers and an almost immediate inflammatory response throughout the implant site. For example, in addition to opening the artherosclerotically obstructed artery, placement of a vascular stent may, in some instances, cause endothelial disruption, fracture of internal lamina and dissection of the media of the diseased vessel. Within three to seven days post injury, several processes may occur including adhesion, and the recruitment and activation of neutrophils, monocytes and lymphocytes in an attempt to destroy the foreign body.
Blood compatible biomaterials are generally developed using one of two approaches. The first method utilizes chemical surface moieties which suppress blood-material interactions. The second method attempts to mimic natural endothelial cells (EC) which line the inner walls of all healthy blood vessels. Endothelial cells generate nitric oxide (NO) which inhibit platelet function and smooth muscle cell proliferation. Materials that include such properties may also be important for the treatment of circulatory diseases.
It may be desirable to provide materials, especially materials for use with medical devices, that can generate nitric oxide in vivo and/or provide anti thrombogenic properties of nitric oxide in a medical device. Such devices may, for example, obviate or minimize the need to administer anticoagulants, which may have clinical risks such as excessive bleeding.
The present disclosure is directed in part to compositions that are capable of generating nitric oxide, e.g., in-vivo. The composition may include a chalcogenide compound or moiety, and may further include a biocompatible matrix. Chalcogenide compounds include those selected from an organoselenium, organotellurium, an organosulfur, and combinations thereof. Chalcogenide compounds may also be enzymes that include at least one of selenium, tellurium, or sulfur; or combinations thereof. The composition may further include a biocompatible matrix.
A biocompatible, thromboresistant coating for use on an implantable medical device is provided herein that includes a chalcogenide compound that induces nitric oxide formation; and a biocompatible matrix incorporating said chalcogenide compound. The biocompatible matrix may include a polymer, which may for example, be hydrophilic. In other embodiments, the matrix may comprise a polymer that includes one or more of: a carboxyl moiety, an aldehyde moiety, or a halide moiety. In a non-limiting example, the matrix includes more than about 0.6 mmol/g carboxyl moieties. Chalcogenide compounds may include a carboxyl and/or amine moiety.
Chalcogenide compounds may be disposed on the surface of the matrix, and/or may be covalently bound to the matrix, e.g., to a polymer, a porous membrane structure, a fibrous matrix, or fumed silica. The coatings and matrices disclosed herein may further include a therapeutic agent.
In an embodiment, the disclosed coatings may further include a layer that is separate from the matrix. For example, the matrix may include a first polymer, and the separate layer may include a second polymer. Such a separate layer may further include a therapeutic agent. In an embodiment, the second polymer may be hydrophilic.
A composition for use in association with a bioimplant is also provided, which includes a matrix covalently bound to a chalcogenide moiety; wherein the chalcogenide moiety is selected from the group consisting of an organoselenium moiety, an organotellurium moiety, or combinations thereof.
A method for direct delivery of nitric oxide to a targeted site in a patient in need thereof is also provided. Generally, the method includes implanting the disclosed coatings and/or compositions directly to the targeted site in the patient.
Also provided are medical devices coated with embodiments of the coatings and compositions disclosed herein.
The embodiments and practices of the present disclosure, other embodiments, and their features and characteristics, will be apparent from the description, drawings and claims that follow.
This disclosure is directed, at least in part, to biocompatible compositions that may be suitable for use with, for example, medical devices. Compositions are provided that include a chalcogenide compound, such as organoselenium compounds, organosulfur compounds, organotellurium compounds, or combinations thereof; and/or chalcogenide containing enzyme(s) incorporated in and/or on a surface of another material or matrix (one non-limitative example of which is a polymer). In other embodiments, a composition includes at least one material/matrix (e.g., polymer) residue covalently bound to an organoselenium, organotellurium, and/or organosulfur moiety; and/or to an enzyme including a chalcogenide element.
This disclosure also provides, in part, a composition for nitric oxide formation, which includes a chalcogenide compound, wherein the chalcogenide compound includes a moiety selected from an organoselenium moiety, an organotellurium moiety, an organosulfur moiety, and combinations thereof; and/or an enzyme including at least one of selenium, tellurium, or sulfur. Exemplary compounds include di-selenium compounds and di-tellurium compounds.
The composition may further include a biocompatible and/or a biodegradable matrix, such as a biocompatible and/or biodegradable polymer. Such polymers may be hydrophilic or hydrophobic. In some embodiments, the matrix includes a polymer that has one or more of: a carboxyl moiety, an aldehyde moiety, an amine moiety, or a halide moiety. In other embodiments, the matrix or polymer includes more than about 0.6 mmol/g carboxyl moieties. Alternatively, the matrix may include a porous membrane structure.
Compositions of the present disclosure include chalcogenide compounds that include a carboxyl moiety and/or an amine moiety. In some embodiments, a chalcogenide compound is immobilized in the polymer and/or matrix, or on a surface of the polymer and/or matrix. In other embodiments, the chalcogenide compound is covalently bound to the polymer and/or matrix. The chalcogenide moiety or compound may include one or more of an organoselenium moiety, an organosulfur moiety, or an organotellurium moiety. In some embodiments, an organoselenium moiety is selected from selenocystamine, selenocystine, 3,3′-diselenodipropionic acid, selenocysteine, ebselen, propyl-selenocystine, allyl-selenocystine, methyl-selenocystine, selenomethionine, selenium choline, and combinations thereof. In other embodiments, a composition may include selenium enzymes, such as glutathione peroxidase and thiredoxin reductase.
A composition is also provided that includes a matrix covalently bound, directly or through a chemical moiety, to a chalcogenide moiety, wherein the chalcogenide moiety is selected from an organoselenium moiety, an organotellurium moiety, an organosulfur moiety, or combinations thereof; and/or an enzyme including at least one of selenium, tellurium, sulfur, and/or combinations thereof.
In some embodiments, the chalcogenide moiety may include a moiety selected from structure I or II:
wherein R1 represents an H, alkyl, aryl or a bond; R2 represents an alkyl, amido, carboxyl, amino, or a bond; R3 represents an alkyl or a bond; A represents independently for each occurrence S, Se, or Te; R4 represents an H or alkyl; the dashed line represents an optional bond included if structure II is cyclic; R5 represents independently for each occurrence, an alkyl, aryl, amido, carboxyl, amino, or a bond; and R6 represents independently for each occurrence an H, carboxyl, amino, aryl, or a bond.
Matrices include for example polyurethane, polyester, polyethyleneimine, polymethacrylate, polytetrafluoroethylene, and polydimethylsiloxane. The matrix may include immobilization moieties attached thereto. Such immobilization moieties may include, but are not limited to, particles, a fibrous matrix such as cellulose, or nano- or micro-particles including cellulose, and fumed silica. Fumed silica derivatized with a chalcogenide may be used as a polymer filler, e.g., may form part of a composition that includes a filled polymer, for example, a filled polyurethane.
Coatings for medical devices that generate nitric oxide are contemplated herein. Such coatings may include a composition of a polymer and a chalcogenide compound. Such coatings may be layered, e.g., may include a first polymer layer having a chalcogenic compound therein, and a second polymer layer. The second polymer layer may have hydrophilic properties and/or may be biodegradable. In some embodiments, the second polymer layer may also include another therapeutic agent.
For example, the coating may include a first layer of polyethylenimine covalently bound to a selenium moiety. Such a first layer may be in, e.g., the form of a hydrogel. The coating may then further include a second layer of polytetrafluoroethylene with a therapeutic agent, e.g., an anti-infective agent.
Also provided herein is an analyte sensor including an electrode surface; and a biocompatible analyte-permeable composition or coating as disclosed herein. The coating may be disposed on the electrode surface of the analyte sensor. It is believed that incorporating the chalcogenide compound may improve, for example, the biocompatibility of the implantable sensors.
Compositions disclosed herein may be administered locally, e.g., at a site of device implantation, to deliver nitric oxide directly. Local administration of the composition may be via a suture, a vascular implant, a stent, a heart valve, a drug pump, a drug delivery catheter, an infusion catheter, a drug delivery guidewire or an implantable medical device. For example, nitric oxide may be delivered directly to a local site by implanting a medical device coated with compositions and/or coatings disclosed herein.
In one aspect of this disclosure, a method for direct delivery of nitric oxide to a targeted site in a patient in need thereof is provided, including administering a composition of the present disclosure directly to the targeted site in the patient.
In another aspect of this disclosure, a medical device is disclosed that includes an embodiment of the composition disclosed herein. Such a medical device includes, but is not limited to an intravascular or extravascular medical device, a balloon, a catheter tip, a prosthetic heart valve, a suture, a surgical staple, a synthetic vessel graft, a stent, a stent graft, a vascular or non-vascular graft, a shunt, an aneurysm filler, an intraluminal paving system, a guide wire, an embolic agent, a filter, a drug pump, an arteriovenous shunt, an artificial heart valve, an artificial implant, a foreign body introduced surgically into the blood vessels or at a vascular or non-vascular site, a lead, a pacemaker, an implantable pulse generator, an implantable cardiac defibrillator, a cardioverter defibrillator, a defibrillator, a spinal stimulator, a brain stimulator, a sacral nerve stimulator, a chemical sensor, a breast implant, an interventional cardiology device, a catheter, plastic tubing, or a dialysis bag or membrane.
Also provided is a method for inhibiting platelet aggregation and platelet adhesion caused by the exposure of blood to a medical device. Such a method includes incorporating at least one composition as disclosed herein into or on the medical device prior to exposing the medical device to blood. In another embodiment, a method for treating an injured tissue in a patient in need thereof includes administering at least one composition disclosed herein, to the site of the injured tissue in the patient. A method of promoting angiogenesis in a subject afflicted with atherosclerosis is also provided, where the method includes implanting a composition disclosed herein to a subject at a tissue locus experiencing or at risk of insufficient blood perfusion.
A method of detecting nitrosothiols in a fluid is also provided, wherein the method includes contacting the fluid with a composition disclosed herein.
In some embodiments, a composition is provided that includes a compound represented by formula III, IV or V:
wherein represents a polymer residue or a fibrous matrix; wherein R1 represents an alkyl, aryl, carboxyl, or a bond; R2 represents an alkyl, aryl amido, carboxyl, amino, or a bond; R3 represents an alkyl or a bond; A represents independently for each occurrence S, Se, or Te; R4 represents an H, aryl, or alkyl; R5 represents an aryl, or alkyl and R6 represents an H, carboxyl, or amino.
A variety of chalcogenide compounds and moieties are contemplated as being within the purview of the present disclosure. In some embodiments, such compounds may generate nitric oxide when in contact with a bodily fluid, for example, blood. Practitioners of the art will readily appreciate the circumstances under which various chalcogenide compounds are appropriate for use in the various compositions and devices disclosed herein.
“Chalcogen compounds” refer to compounds and moieties that include atoms within column 6A of the periodic table. Group 6A or chalcogen compounds may also be referred to as Group 16 compounds. Group 6A atoms include at least one of: oxygen, sulfur, selenium, tellurium, and polonium. “Chalcogenide compounds” refer to compounds and moieties that include heavier Group 6A atoms, and include at least one of: sulfur, selenium, tellurium, and polonium. Both unsubstituted chalcogen and chalcogenide compounds and substituted chalcogen and chalcogenide compounds are contemplated by the terms “chalcogenide compounds” and “chalcogen compounds.” Substituted chalcogenide compounds refer to compounds and moieties having substituents replacing a hydrogen on one or more carbons of a hydrocarbon backbone. Such substituents may include, for example, a halogen, a hydroxyl, a carbonyl (such as a carboxyl, an alkoxycarbonyl, a formyl, or an acyl), a thiocarbonyl (such as a thioester, a thioacetate, or a thioformate), an alkoxyl, a phosphoryl, a phosphonate, a phosphinate, an amino, an amido, an amidine, an imine, a cyano, a nitro, an azido, a sulfhydryl, an alkylthio, a sulfate, a sulfonate, a sulfamoyl, a sulfonamido, a sulfonyl, a heterocyclyl, an aralkyl, or an aromatic or heteroaromatic moiety.
Without being limited to any theory, it is believed that chalcogenide compounds (such as substituted or unsubstituted organoselenium, organotellurium, organosulfur compounds, and combinations thereof); and/or enzymes including selenium, sulfur, tellurium, and combinations thereof, when exposed to endogenous or exogenous sources of nitrates, nitrites, or nitrosothiols (optionally in the presence of reducing agents), generate nitric oxide and/or an active species that generates NO within and/or at the surface of a composition. It is to be understood that the sources of nitrates, nitrites, nitrosothiols and reducing agents may be from bodily fluids such as blood, within the composition, within a device, and/or may be injected intravenously or otherwise added or administered to the bodily fluid of interest. Such reducing agents may include biochemical or organic reducing agents such as ascorbic acid, NADH, NADPH, thiol compounds such as glutathione, cysteine, dithreitol, 2-mercaptoethanol, 2-mercaptoethylamine, tris[2-carboethyl]phosphine hydrochloride, and the like. As used herein, the term “nitric oxide” or “NO” encompasses uncharged nitric oxide and charged nitric oxide species, including for example, nitrosonium ion and nitroxyl ion.
Such chalcogenide compounds may include alkylthio compounds and moieties, thiocarbonyl moieties, and selenoalkyl compounds. Exemplary organoselenium compounds include selenocystamine, selenocystine, 3,3′-diselenodipropionic acid, selenocysteine, ebselen, propyl-selenocystine, allyl-selenocystine, methyl-selenocystine, selenomethionine, and selenium choline. In some embodiments, organoselenium and/or organotellurium compounds may be diselenium or ditellurium compounds, e.g., comprise an —Se—Se— moiety and/or a —Te—Te— moiety.
Selenium compounds also encompass enzymes including selenium. Exemplary enzymes include glutathione peroxidase and thiredoxin reductase.
Sulfur compounds include organosulfur compounds, such as 2-mercaptoethanol, dithiothreitol, 2-mercaptoethylamine-HCl, cystamin, 2-aminoethyl-2-aminoethanethiolsulfonate, 3-mercaptopropionic acid, 2-(trimethylsilyl)ethanethiol, (3-mercaptopropyl)trimehoxysilane and sulfur-containing amino acids, peptides and their derivatives, such as cysteine and cystine, glucose-cysteine, N-isobutyrylcysteine, 2,3-dimercaptosuccinic acid-cysteine (1-2) mixed disulfide, and peptides containing cysteine residue, enzymes, proteins or their derivatives modified or synthesized to have S-moieties, for example, albumin and albumin-Cys, and polymers containing the above-mentioned S-containing molecules in their backbone or side-chains.
Tellurium compounds may include organotellurium compounds. Tellurium compounds may further include sulfur and/or selenium. Exemplary tellurium compounds include those ditellurium compounds that can be represented by the formula:
Ar—Te—Te—Ar
where Ar is a substituted or unsubstituted aryl moiety, such as for example, a heterocycle. A particular exemplary tellurium compound contemplated herein can be represented by the following formula:
Mixed tellurium-selenium, mixed selenium-thiol, or mixed tellurium-thiol species are also contemplated by this disclosure. For example, compounds such as R—Se—Te—R, R—Se—S—R, R—Te—S—R, are provided, wherein each R represents independently an organic moiety. In some embodiments, such species will yield, after reduction, one or more selenol, thiol, or tellelanol species that are catalytic.
Organoselenium compounds may further include sulfur. For example, organoselenium compounds such as molecules, enzymes, proteins or polymers, or their composites can include sulfhydryl, disulfide, and selenosulfide functional moieties, as well as selenol/selenolate and diselenide moieties. In some embodiments, sulfur-containing moieties may stabilize catalytic sites by forming, for example, a selenosulfide bridge. Such a bridge may be reversibly cleavable to produce catalytic sites on an organoselenium compound.
Selenosulfide bonds may form as intermediate state during redox reactions if S-moieties exist in proximity of Se-sites, for example, by coupling the above-mentioned species in a Se-immobilized polymer matrix. Compounds that include such bonds are contemplated by this disclosure. Such compounds include glutathione-glutaselenone (GS—SeG), Cys-Sec (a selenosulfide, Cys-cysteine, Sec-selenocysteine), Glutathione peroxidase-Se—SG (or a compound containing a-Cys, selenosulfide linkage), and polymers that include such a linkage, e.g., Polymer-Se—S-Polymer.
Further chalcogenide compounds and moieties include those with the structure:
where R is any organic moiety, such as a drug, saccharide, or other moiety; R1 is selected from: an alkyl, amino, amido, carboxyl, or hydrogen; R2 is selected from a carboxyl, alkoxy, alkyl, amino, or H; and A is selenium, sulfur, or tellurium.
In some embodiments, the chalcogenide compounds or moieties have been reduced by a reducing agent such as a borohydride (non-limiting examples of which include sodium borohydride, sodium cyanoborohydride, zinc borohydride) or other hydrides such as lithium aluminumhydride and butyl tinhydride, and diimide. Such reduced moieties are contemplated by the reference to a particular chalcogenide moiety. In other embodiments, the chalcogenide compounds or moieties include two or more chalcogenide compounds.
A variety of polymers may be used in the embodiments disclosed herein. A polymer for such use may be biocompatible. It is to be understood that both non-biodegradable and/or biodegradable polymers may be used in the subject disclosure. As discussed below, the choice of polymer will depend in part on a variety of physical and chemical characteristics of such polymer and the use to which such polymer may be put.
Representative natural polymers and matrices include proteins, such as zein, modified zein, casein, gelatin, gluten, serum albumin, or collagen, and polysaccharides, such as cellulose, dextrans, hyaluronic acid, polymers of alginic acid, and natural fibrous matrix, such as filter paper.
Fibrous matrices contemplated by this disclosure include cellulose and cellulose based matrices, cellulose derivatives including cellulose acetate and cellulose phthalate, cellulose composite membranes, cellulose particles including micro- and nano-particles, fabrics such as linen, cotton, rayon, nylon and polyester based fabrics. Other matrices include silicon dioxide particles, such as fumed silica. In other embodiments, biocompatible matrices contemplated by this disclosure include silicon-containing polymers, hydrogels, etc.
Representative synthetic polymers include polyphosphazines, poly(vinyl alcohols), polyamides, polycarbonates, polyalkylenes, polyacrylamides, polyanhydrides, poly(phosphoesters), polyalkylene glycols, polyalkylene oxides, polyalkylene terephthalates, polyvinyl ethers, polyvinyl esters, polyvinyl halides, polyviniylpyrrdlidone, polyglycolides, polysiloxanes, polyphosphates, polyesters, and polyurethanes. For example, polymers may include polydimethylsiloxane, ethylene vinyl acetate, nylons, polyacrylics, polymethyl methacrylate, polyethylenes, polypropylenes, polystyrenes, poly(vinyl chloride) (PVC), and polytetrafluoroethylene (PTFE). Silicon rubbers may also be used as a polymer.
Synthetically modified natural polymers include alkyl celluloses, hydroxyalkyl celluloses, cellulose ethers, cellulose esters, and nitrocelluloses. Other like polymers of interest include, but are not limited to, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxybutyl methyl cellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, cellulose acetate phthalate, carboxymethyl cellulose, cellulose triacetate and cellulose sulfate sodium salt.
In some embodiments, compositions of this disclosure include a biocompatible polymer. Examples of biocompatible polymers include poly(hydroxyvalerate), poly(L-lactic acid), polycaprolactone, poly(lactide-co-glycolide), poly(hydroxybutyrate), poly(hydroxybutyrate-co-valerate), polydioxanone, polyorthoesters, polyanhydrides, poly(glycolic acid), poly(D,L-lactic acid), poly(glycolic acid-co-trimethylene carbonate), polyphosphoesters, polyphosphoester urethanes, poly(amino acids), cyanoacrylates, poly(trimethylene carbonates), poly(iminocarbonate), copoly(ether-esters) (e.g. PEO/PLA), polyalkylene oxalates, polyphosphazenes and biomolecules such as fibrin, fibrinogen, cellulose, starch, collagen and hyaluronic acid. Polyurethanes, silicones, and polyesters may be used, as well as polyolefins, polyisobutylene and ethylene-alphaolefin copolymers; acrylic polymers and copolymers, vinyl halide polymers and copolymers, such as polyvinyl chloride; polyvinyl ethers, such as polyvinyl methyl ether; polyvinylidene halides, such as polyvinylidene fluoride and polyvinylidene chloride; polyacrylonitrile; polyvinyl ketones; polyvinyl aromatics, such as polystyrene; polyvinyl esters, such as polyvinyl acetate; copolymers of vinyl monomers with each other and olefins, such as ethylene-methyl methacrylate copolymers, acrylonitrile-styrene copolymers, ABS resins, and ethylene-vinyl acetate copolymers; polyamides, such as Nylon 66 and polycaprolactam; alkyd resins; polycarbonates; polyoxymethylenes; polyimides; polyethers; epoxy resins; rayon; rayon-triacetate; cellulose, cellulose acetate, cellulose butyrate; cellulose acetate butyrate; cellophane; cellulose nitrate; cellulose propionate; cellulose ethers; and carboxymethyl cellulose. Particular polymers contemplated herein include polyethyleneimine, polymethacrylate, polytetrafluoroethylene, and polydimethylsiloxane.
Polymers that resist protein adsorption may also be used in compositions contemplated by this disclosure. Such polymers include polyethylene glycols, polyurethanes and silicone elastomers, silica-containing polymers, and poly(vinyl)chlorides.
Other polymers that may be used include tecophilic polyurethanes, PDMS co-polymers, carbamates, and the like. In some embodiments, polymers that regulate water uptake may be used in embodiments of the disclosed composition. Polymers contemplated by this disclosure may also include those polymers that control the diffusion of selenium compounds, and/or polymers that control the diffusion of S-nitrosothiols.
All of the subject polymers may be provided as copolymers or terpolymers. These polymers may be obtained from chemical suppliers, or synthesized from monomers using standard techniques.
Compositions and coatings contemplated herein include a matrix, such as one or more of the polymer(s) as described above, and a chalcogenide compound, such as an organoselenium, an organosulfur, and/or organotellurium compound; and/or an enzyme that includes selenium, sulfur and/or tellurium. In some embodiments, such a composition may produce nitric oxide when in contact, for example, with a bodily fluid such as blood.
Such compositions may be suitable for use as a layer or membrane, or in a layer or membrane, disposed, at least in part, on a sensing layer, or on an electrode surface of an analyte sensor, or on a medical device. In part, a biocompatible analyte-permeable composition of the present disclosure useful for use in analyte detection includes: (a) a selenium, tellurium, and/or sulfur compound; a selenium, tellurium, and/or sulfur containing enzyme; residues or moieties of the same; and/or combinations thereof, and (b) a biocompatible polymer that is at least partially permeable to the analyte(s) of interest.
In certain embodiments, a chalcogenide compound is incorporated into a polymer. The chalcogenide compound may be covalently attached to the polymer, dispersed throughout the polymer, and/or disposed on the surface of a polymeric layer or matrix. Various methods of covalent attachment of the chalcogenide compound or moiety may be employed. For example, innate amine groups (—NH2) in selenocystamine may be reacted with a variety of reaction sites generally found in functionalized polymer backbones, such as carboxyl groups (—COOH), or aldehyde groups, (—CHO) and halides (—Cl, Br, I, F). Selenium and/or sulfur containing enzymes may be immobilized via a similar approach using any available reactive groups on the enzymes. In another embodiment, a reactive chalcogenide agent may be first coupled, bonded or associated with another small molecule, a protein, an enzyme, a polymer or a polymeric material to form a conjugate, and then further immobilized within or on the surface of a desired substrate, e.g., a metal surface of a medical device. In yet another embodiment, the catalytic moiety for S-nitrosothiol decomposition may be achieved through covalent coupling reactions of a functional group on the surface of a desired material such as polymeric films, glass surfaces, and/or the like.
In one alternative embodiment, hydrophobic organoselenium, organosulfur, or organotellurium compounds can be selected and incorporated into a material possessing a hydrophobic domain in its internal structure, for example, poly(vinyl chloride), polyurethanes, and the like. For such a composition, a chalcogenide compound may be added to a polymer or a composition including a polymer. A variety of methods are known in the art for encapsulating a substance in a polymer. For example, the agent or substance may be dissolved to form a homogeneous solution of reasonably constant concentration in the polymer composition, or it may be dispersed to form a suspension or dispersion within the polymer composition at a desired level of “loading” (grams of biologically active substance per grams of total composition including the agent, usually expressed as a percentage). For example, a composition comprising a chalcogenide compound may have 0.01%, 1%, 3% or even 5% or more by weight of a chalcogenide compound.
The terms “incorporated” and “encapsulated” are art-recognized when used in reference to an chalcogenide compound (or other material) and a polymeric composition, such as a composition of the present disclosure. The terms may contemplate any manner by which a chalcogenide compound or other material is incorporated into a polymer matrix, including, for example: attached to a monomer of such polymer (by covalent or other binding interaction) and having such monomer be part of the polymerization to give a polymeric formulation, distributed throughout the polymeric matrix, appended to the surface of the polymeric matrix (by covalent or other binding interactions), encapsulated inside the polymeric matrix, blending, mixing, swelling etc. The term “co-incorporation” or “co-encapsulation” refers to the incorporation of chalcogenide compound or other material and at least one other agent or other material in a subject composition. When a therapeutic agent is incorporated in, e.g., a matrix, it is to be understood that such therapeutic agent(s) can be released from such matrix in a contemplated fashion, e.g., the matrix may deliver a therapeutically effective amount of a therapeutic agent.
In an embodiment, the physical form in which any chalcogenide compound or other material is encapsulated in polymers may vary with the particular embodiment. For example, a selenium compound, tellurium compound, sulfur compound or other material may be first encapsulated in a microsphere and then combined with the polymer in such a way that at least a portion of the microsphere structure is maintained. Alternatively, a chalcogenide compound or other material may be sufficiently immiscible in the polymer, and as such, is dispersed as small droplets, rather than being dissolved, in the polymer. Any form of encapsulation or incorporation is contemplated by the present disclosure, in so much as the effectiveness over time of any encapsulated selenium compound or other material determines whether the form of encapsulation is sufficiently acceptable for any particular use. For example, the chalcogenide compound may be incorporated into a porous layer of the matrix or into pores that are part of a natural or synthetic matrix. In an embodiment, a polymer derivatized with a chalcogenide compound may then be cross-linked to form a hydrogel.
Suitable compositions may also include a wide range of additional materials. For example, materials may be incorporated into the compositions that alter the physical and chemical properties, including for example, the capability of preventing biofouling of the resulting composition and/or the analyte permeability of the composition. Without being limited thereto, such materials may include diluents, binders and adhesives, lubricants, disintegrants, colorants, bulking agents, flavorings, sweeteners, and miscellaneous materials such as buffers and adsorbents, in order to prepare a particular medicated composition. It is to be understood that such additional materials are selected so that none of these additional materials will substantially interfere with the intended purpose of the subject composition.
The subject compositions and coatings may include a pharmaceutically acceptable carrier. The term “pharmaceutically acceptable carrier” is art-recognized, and includes, for example, pharmaceutically acceptable materials, compositions or vehicles, such as a liquid or solid filler, diluent, excipient, solvent or encapsulating material, involved in carrying or transporting any subject composition from one organ, or portion of the body, to another organ, or portion of the body. Each carrier must be “acceptable” in the sense of being compatible with the other ingredients of a subject composition and not injurious to the patient. In certain embodiments, a pharmaceutically acceptable carrier is non-pyrogenic. Some examples of materials which may serve as pharmaceutically acceptable carriers include: (1) sugars, such as lactose, glucose and sucrose; (2) starches, such as corn starch and potato starch; (3) cellulose, and its derivatives, such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; (4) glycols, such as propylene glycol; (5) polyols, such as glycerin, sorbitol, mannitol and polyethylene glycol; (6) esters, such as ethyl oleate and ethyl laurate; (7) buffering agents; (8) ethyl alcohol; (9) other non-toxic compatible substances employed in medical device coating formulations.
In addition to a chalcogenide compound, the subject compositions and coatings may contain therapeutic agents. Therapeutic agents in a subject composition may vary widely with the purpose for the composition. The term “therapeutic agent” includes without limitation, medicaments; vitamins; mineral supplements; substances used for the treatment, prevention, diagnosis, cure or mitigation of disease or illness; substances which affect the structure or function of the body; or pro-drugs, which become biologically active or more active after they have been placed in a predetermined physiological environment. It is to be understood that compositions contemplated by this disclosure may include one or more nitric oxide releasing or generating agents alone or in combination with one or more nitric oxide generating agents or chalcogenide compounds, and can include one or more other therapeutic agents.
Suitable “therapeutic agents” useful in the disclosure, include, but are not limited to, antithrombogenic agents (such as, for example, heparin, covalent heparin, hirudin, hirulog, coumadin, protamine, argatroban, D-phenylalanyl-L-poly-L-arginyl chloromethyl ketone, and the like); thrombolytic agents (such as, for example, urokinase, streptokinase, tissueplasminogen activators, and the like); fibrinolytic agents; vasospasm inhibitors; potassium channel activators (such as, for example, nicorandil, pinacidil, cromakalim, minoxidil, aprilkalim, loprazolam and the like); calcium channel blockers; antihypertensive agents; anti-infective agents including antiviral agents, antimicrobial agents and antifungal agents, antimicrobial agents or antibiotics (such as, for example, adriarnycin, and the like); antiplatelet agents (such as, for example, aspirin, ticlopidine, a glycoprotein IIb/IIIa inhibitor, surface glycoprotein receptors and the like); antimitotic, antiproliferative agents or microtubule inhibitors (such as, for example, taxanes, colchicine, methotrexate, azathioprine, vincristine, vinblastine, cytochalasin, fluorouracil, adriamycin, mutamycin, tubercidin, epothilone A or B, discodermolide, and the like); antisecretory agents (such as, for example, retinoid, and the like); remodelling inhibitors; antisense nucleotides (such as, for example, deoxyribonucleic acid, and the like); anti-cancer agents (such as, for example, tamoxifen citrate, acivicin, bizelesin, daunorubicin, epirubicin, mitoxantrone, and the like); steroids (such as, for example, dexamethasone, dexamethasone sodium phosphate, dexamethasone acetate, β-estradiol, and the like); non-steroidal antiinflammatory agents (NSAID); COX-2 inhibitors; 5-lipoxygenase (5-LO) inhibitors; leukotriene A4 (LTA4) hydrolase inhibitors; 5-HT agonists; HMG-CoA inhibitors; antineoplastic agents, thromboxane inhibitors; decongestants; diuretics; sedating or non-sedating anti-histamines; inducible nitric oxide synthase inhibitors; opioids, analgesics; Helicobacter pylori inhibitors; proton pump inhibitors; isoprostane inhibitors; vasoactive agents; beta.-agonists; anticholinergic; mast cell stabilizers; immunosuppressive agents (such as, for example cyclosporin, rapamycin, everolimus, actinomycin D and the like); growth factor antagonists or antibodies (such as, for example, trapidal (a PDGF antagonist), angiopeptin (a growth hormone antagonist), angiogenin, and the like); dopamine agonists (such as, for example, apomorphine, bromocriptine, testosterone, cocaine, strychnine, and the like); radiotherapeutic agents; heavy metals functioning as radiopaque agents (such as, for example, iodine-containing compounds, barium-containing compounds, gold, tantalum, platinum, tungsten, and the like); biologic agents (such as, for example, peptides, proteins, enzymes, extracellular matrix components, cellular components, and the like); angiotensin converting enzyme (ACE) inhibitors; angiotensin II receptor antagonists; renin inhibitiors; free radical scavengers, iron chelators or antioxidants (such as, for example, ascorbic acid, alpha tocopherol, superoxide dismutase, deferoxamine, 21-aminosteroid, and the like); sex hormones (such as, for example, estrogen, and the like); antipolymerases (such as, for example, AZT, and the like); antiviral agents; photodynamic therapy agents (such as, for example, 5-aminolevulinic acid, meta-tetrahydroxyphenylchlorin, hexadecafluoro zinc phthalocyanine, tetramethyl hematoporphyrin, rhodamine 123, and the like); antibody targeted therapy agents (such as, for example, IgG2 Kappa antibodies against Pseudomonas aeruginosa exotoxin A and reactive with A431 epidermoid carcinoma cells, monoclonal antibody against the noradrenergic enzyme dopamine beta-hydroxylase conjugated to saporin, and the like); and gene therapy agents.
The compounds and compositions of the disclosure may also be administered in combination with other medications used for the treatment of diseases or disorders.
The phrase “pharmaceutically acceptable” is art-recognized. In certain embodiments, the term includes compositions, polymers and other materials and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problems or complications, commensurate with a reasonable benefit/risk ratio.
In an embodiment, the composition may include lipophilic salts of nitrite/nitrate or nitrosothiols within its matrix to create a reservoir of nitrite/nitrate or nitrosothiol that, for example, can continuously leak to a surface.
Compositions of this disclosure may also include other agents that assist prevention of biofouling or microbial interference. Such agents include antifungals and antibiotics. For example, gentamycin and/or penicillin, and/or other broad-spectrum antibiotics and antifungals (e.g., ketaconazole) may be incorporated into the enzyme mixture or the polymer matrix to prevent microbial growth.
Plasticizers and stabilizing agents known in the art may be incorporated in polymers of the present disclosure. In certain embodiments, additives such as plasticizers and stabilizing agents are selected for their biocompatibility.
An embodiment of the composition of this disclosure may further contain one or more adjuvant substances, such as fillers, thickening agents or the like. In other embodiments, materials that serve as adjuvants may be associated with the polymer matrix. Such additional materials may affect the characteristics of the formed polymer matrix. For example, fillers, such as bovine serum albumin (BSA), mouse serum albumin (MSA), or silica particles, may be associated with or dispersed within the polymer matrix. For example, a filler may include a chalcogenide compound immobilized to a fumed silica particle. In certain embodiments, the amount of filler may range from about 0.1% to about 50% or more by weight of the polymer matrix. In other embodiments, the filler may be present in any of the following amounts: about 2.5%, 5%, 10%, 25%, or 40%. Other fillers known to those of skill in the art, such as carbohydrates, sugars, starches, saccharides, celluoses and polysaccharides, including mannitose and sucrose, may be used in certain embodiments in the present disclosure. Buffers, acids and bases may also be incorporated in the subject compositions to adjust the pH.
The charge, lipophilicity or hydrophilicity of any embodiment of the polymeric matrix may be modified by attaching or incorporating in some fashion an appropriate compound to the surface of a composition or membrane. For example, surfactants may be used to enhance wettability of poorly soluble or hydrophobic compositions. Examples of suitable surfactants include dextran, polysorbates and sodium lauryl sulfate. In general, surfactants are used in low concentrations, generally legs than about 5%.
Binders are adhesive materials that may be incorporated in polymeric formulations to bind and maintain matrix integrity. Binders may be added as dry powder or as a solution. Sugars, natural polymers and synthetic polymers may act as binders. Materials added specifically as binders are generally included in the range of about 0.5%-15% w/w of the matrix formulation. Certain materials may exhibit multiple properties, such as microcrystalline cellulose, which is a spheronization enhancer, and may also have additional binding properties.
Various further coatings may be applied to modify the properties of a coating or composition. Three exemplary types of coatings are seal, gloss and enteric coatings. Other types of coatings having various dissolution or erosion properties may be used to further modify subject matrices behavior, and such coatings are readily known to one of ordinary skill in the art.
When a composition that includes a nitric oxide generating agent such as a chalcogenide compound, for example, an organoselenium, organothiol, or organotellurium compound and/or a selenium, tellurium or sulfur containing enzyme, is placed in contact with blood, for example, it may facilitate the conversion of endogenous S-nitrosothiols to NO as shown schematically in
Also contemplated by this disclosure are coatings for use on medical devices. Such a coating may include a polymer and a chalcogenide compound. A coating may include one or more layers, for example, a coating may include a first polymer layer including the chalcogenide compound, and optionally a second polymer layer. The first and/or second layer may further include one or more additional therapeutic agents. The second layer may be disposed on the first layer, or the first layer may be disposed on the second layer. The first and/or second layer may be biodegradable and/or hydrophilic.
As previously stated, compositions and coatings of the instant disclosure may be used, for example, on or in a medical device, and in some embodiments, on a metal surface of a medical device. “Medical device”, as used herein, refers to any intravascular or extravascular medical devices, medical instruments, foreign bodies including implants and the like. Examples of intravascular medical devices and instruments include balloons or catheter tips adapted for insertion, prosthetic heart valves, sutures, surgical staples, synthetic vessel grafts, stents (e.g., Palmaz-Schatz, Wiktor, Crown, Mutlilink, GFX stents), stent grafts, vascular or non-vascular grafts, shunts, aneurysm fillers (including GDC, Guglilmi detachable coils), intraluminal paving systems, guide wires, embolic agents (for example, polymeric particles, spheres and liquid embolics), filters (for example, vena cava filters), drug pumps, arteriovenous shunts, artificial heart valves, artificial implants, foreign bodies introduced surgically into the blood vessels or at vascular or non-vascular sites, leads, pacemakers, implantable pulse generators, implantable cardiac defibrillators, cardioverter defibrillators, defibrillators, spinal stimulators, brain stimulators, sacral nerve stimulators, chemical sensors, breast implants, interventional cardiology devices, catheters, and the like. Examples of extravascular medical devices and instruments include plastic tubing, dialysis bags or membranes whose surfaces come in contact with the blood stream of a patient.
After a device or artificial material has been coated at least partially with a composition or coating as disclosed herein, it will be substantially suitable for its intended use, including, for example, implantation as a heart valve, insertion as a catheter, insertion as a stent, or for cardiopulmonary oxygenation or hemodialysis.
Also disclosed herein are methods for the administration of a therapeutically effective amount of the compounds and compositions described herein for treating cardiovascular diseases and disorders including, for example, restenosis, vasospasm, atherosclerosis, and diseases where vasodilation of arteries is indicated. For example, the patient can be administered a therapeutically effective amount of a composition contemplated herein. A therapeutically effective amount may be, for example, based on the amount of a chalcogenide compound necessary to provide a therapeutically effective amount of nitric oxide.
The term “therapeutic effect” is art-recognized and refers to a local or systemic effect in animals particularly mammals, and more particularly humans) caused by a pharmacologically active substance. The term thus means any substance intended for use in the diagnosis, cure, mitigation, treatment or prevention of disease, or in the enhancement of desirable physical or mental development and/or conditions in an animal or human. The phrase “therapeutically-effective amount” means that amount of such a substance that produces some desired local or systemic effect, or for example, generates an amount of nitric oxide to produce some desired effect, at a reasonable benefit/risk ratio applicable to any treatment. The therapeutically effective amount of such a substance will vary depending upon the subject and disease condition being treated, the weight and age of the subject, the severity of the disease condition, the manner of administration and the like, which can readily be determined by one of ordinary skill in the art. For example, certain compositions of the present invention may be administered in a sufficient amount to produce a reasonable benefit/risk ratio applicable to such treatment.
Another embodiment of the disclosure provides methods for the inhibition of platelet aggregation and platelet adhesion caused by the exposure of blood (including blood components or blood products) to a medical device by incorporating a composition disclosed herein and disposing said medical device on or in a patient.
In some embodiments, a method is provided for patients in need thereof, for promoting angiogenic effects, such as enhancing vascularization/blood flow to ischemic cells/tissues. As a non-limiting example, the coatings or compositions may be used for promoting angiogenesis when coronary artery disease, e.g., ischemic myocardium, myocardial infarction, ischemic cardiomyopathy, or peripheral arterial disease, such as chronic limb ischemia claudication (skeletal muscle), rest pain/ischeric ulceration/gangrene is present or suspected. Treatment of a patient in need of promoting angiogenesis may be indicated in the event of, for example, ischemic stroke/neuropathy, such as brain/nerve tissue, for example, ischemic pneumbra around stroke/infarct.
A method is also provided to promote healing and/or endothelialization of intravascular luminal surfaces in a patient in need thereof, for example, to promote endothelialization of unstable/ulcerated atherosclerotic plaque, for example in coronary/carotid arteries, or on de-endothelialized luminal surfaces such as those found following an endarterectomy, for example within the carotid artery, thrombectomy (either/or arterial/venous), angioplasty, such as balloon, laser, or cryogenic angioplasty, an atherectomy, or following thrombolysis, by administering a composition disclosed herein.
Compositions provided herein may also assist in resolution of acute, or chronic arterial and/or venous thrombosis, for example revascularization and/or neovascularization and/or recanalization. In another embodiment, compositions are provided that promote development of neocapillary beds for gene therapy applications, organ regeneration applications, and for bioartificial hybrid organs (e.g. pancreas, kidney, lung, liver) placement. Methods are also provided to promote and/or enhance wound healing and/or for promoting granulation tissue, for example, for chronic wounds such as ischemic, diabetic, neuropathic, and venous statis based wounds.
In one embodiment, the compositions disclosed herein may be used to prevent fibrous tissue formation after incisions, or to treat neointimal hyperplasia. For example, a method is provided herein of treating a site of vascular compromise to seal a puncture or opening, and to treat, suppress or prevent a tissue response at such site, by administering a composition of this disclosure. In an embodiment, the method may include administering a nitric oxide agent or composition including a nitric oxide agent, such as the embodiments disclosed herein, or a nitric oxide agent and a hemostatic device or material, and applying, for example, the composition to the site.
Compositions disclosed herein may also be used to prevent incorporation and/or tissue encapsulation of medical devices, or surfaces thereof, for example, artificial or natural replacement surfaces, for example, placed in body cavities such as the thorax, abdomen, and/or hernia, devices such as implantable biosensors, for example intravascular, brain, heart, gut sensors, pacemakers/leads, implantable drug delivery systems, and other biomechanical devices/surfaces such as bioartificial organs, joints, or heart valves. The compositions disclosed herein may improve biocompatibility of, e.g., an implantable device such as a sensor, as compared to an implantable device that does not include a composition of the disclosure. For example, a device including an embodiment of the composition disclosed herein may be placed in the body, for example, for twice the duration as compared to a device without the disclosed composition, with substantially little or no adverse effect to the patient.
Another embodiment of the disclosure relates to local administration of a composition disclosed herein to the site of injured or damaged tissue (e.g., damaged blood vessels) for the treatment of the injured or damaged tissue. Such damage may result from the use of a medical device in an invasive procedure. Thus, for example, in treating blocked vasculature by, for example, angioplasty, damage may, in some instances, result to the blood vessel. Such damage may be treated by use of the compounds and compositions described herein. In addition to repair of the damaged tissue, such treatment may also be used to alleviate and/or delay re-occlusions, for example, restenosis. The compounds and compositions can be locally delivered using any of the methods known to one skilled in the art, including but not limited to, a drug delivery catheter, an infusion catheter, a drug delivery guidewire, an implantable medical device, and the like. In one embodiment, all or most of the damaged area is coated with a disclosed composition herein per se, or in a pharmaceutically acceptable carrier or excipient which serves as a coating matrix, including the matrix described herein. This coating matrix can be of a liquid, gel, semisolid or solid consistency. The composition can be applied in combination with one or more therapeutic agents, such as those listed herein. The carrier or matrix may be made of, or include agents which provide for metered or sustained release of the therapeutic agents.
In treating cardiovascular diseases and disorders, the compositions disclosed herein may be administered directly to the damaged vascular or non-vascular surface intravenously by using an intraarterial or intravenous catheter, suitable for delivery of the compositions to the desired location. For example, disclosed coatings, disposed on a medical device, may be used to deliver chalcogenide agents to desired location for generation of nitric oxide in-vivo. The location of damaged arterial surfaces is determined by conventional diagnostic methods, such as X-ray angiography, performed using routine and well-known methods available to one skilled in the art. In addition, administration of the composition using an intraarterial or intravenous catheter is performed using routine methods well known to one skilled in the art. Typically, the compound or composition is delivered to the site of angioplasty through the same catheter used for the primary procedure, usually introduced to the carotid or coronary artery at the time of angioplasty balloon inflation. The composition may slowly decompose at body temperature over a prolonged period-of time, releasing nitric oxide at a rate effective to treat cardiovascular diseases and disorders including, for example, restenosis.
“Cardiovascular disease or disorder” refers to any cardiovascular disease or disorder known in the art, including, but not limited to, restenosis, coronary artery disease, atherosclerosis, atherogenesis, cerebrovascular disease, angina, ischemic disease, congestive heart failure or pulmonary edema associated with acute myocardial infarction, thrombosis, high or elevated blood pressure in hypertension, vasospasm, platelet aggregation, platelet adhesion, smooth muscle cell proliferation, vascular or non-vascular complications associated with the use of medical devices, wounds associated with the use of medical devices, vascular or non-vascular wall damage, peripheral vascular disease, neoinitimal hyperplasia following percutaneous transluminal coronary angiograph, and the like. Complications associated with the use of medical devices may occur as a result of increased platelet deposition, activation, thrombus formation or consumption of platelets and coagulation proteins. Such complications, which are within the definition of “cardiovascular disease or disorder,” include, for example, myocardial infarction, pulmonary thromboembolism, cerebral thromboembolism, thrombophlebitis, thrombocytopenia, bleeding disorders and/or any other complications which occur either directly or indirectly as a result of the foregoing disorders.
“Restenosis” is a cardiovascular disease or disorder that refers to the closure of a peripheral or coronary artery following trauma to the artery caused by an injury such as, for example, angioplasty, balloon dilation, atherectomy, laser ablation treatment or stent insertion. Restenosis may also occur following a number of invasive surgical techniques, such as, for example, transplant surgery, vein grafting, coronary artery bypass surgery, endarterectomy, heart transplantation, balloon angioplasty, atherectomy, laser ablation, endovascular stenting, and the like.
“Atherosclerosis” is a form of chronic vascular injury in which some of the normal vascular smooth muscle cells in the artery wall, which ordinarily control vascular tone regulating blood flow, change their nature and develop “cancer-like” behavior. These vascular smooth muscle cells become abnormally proliferative, secreting substances such as growth factors, tissue-degradation enzymes and other proteins, which enable them to invade and spread into the inner vessel lining, blocking blood flow and making that vessel abnormally susceptible to being completely blocked by local blood clotting, resulting in the death of the tissue served by that artery. “Blood” includes blood products, blood components and the like.
Also contemplated by this disclosure is a sensor for detecting analytes, such as for example, for detecting S-nitrosothiols in blood and/or tissue. Such analytes include nitrosothiol and glucose. Such sensors may be implantable for in-vivo use or subcutaneous use, or may be used externally on bodily fluids accessible without surgical or other invasive procedures. Alternatively, the disclosed sensors may be used on fluids analyzed remotely. Such sensors may be used to, for example, obtain measurements of the S-nitrosothiol content in a sample or patient over several days.
Embodiments of the coatings, compositions and methods disclosed herein may be used in combination with other treatment modalities in certain embodiments. As examples, the sensors, devices and methods of the present disclosure may be used in conjunction with surgery and/or with other sensors. Still further, the sensor disclosed herein may be capable of sensing more than one analyte simultaneously or in a step wise fashion, or may be used with systemic therapy, for example, insulin administration, or a combination of these modalities. For example, analyte sensors may be used in combination with a variable rate or programmable implantable insulin infusion pump.
Contemplated by this disclosure are analyte sensors, such as those in contact with bodily fluids of a patient, those in contact with an interstitial space in a patient, or those which contact blood subcutaneously or in a vein or artery, saliva, urine, perspiration, and the like. Electrodes for use in analyte sensors include those electrodes functioning on an amperometric basis.
The disclosure having been generally described, it will be more readily understood by reference to the following examples which are included merely for purposes of illustration of certain aspects and embodiments of the present disclosure, and are not intended to limit the disclosure in any way.
A hydrophobic organoselenium catalyst, ebselen, is incorporated into a hydrophilic polyurethane (Tecophilic, SP-60-A, 20%-water absorption) film that can be subsequently mounted on an electrochemical NO sensor for the detection of RSNO species. A NO sensor configuration is used that is similar to that disclosed in U.S. Patent Publication No. 2004/0224868, hereby incorporated by reference in its entirety. 38 mg of the polyurethane is dissolved in 2 ml of THF solution containing 2 mg of ebselen. The polymeric film doped with catalytic selenium agent is prepared by casting 0.5 ml of the cocktail solution onto a 2.4 cm2 glass slide. A patch of the resulting film is added as an outer catalytic membrane at the distal tip of an amperometric NO selective sensor to create an RSNO sensor.
Surface carboxyl groups on metal-chelating resin particles (Chelex, 0.6 mmol-carboxyl group/g, 0.5 mm particle size) are coupled with the amine ends of selenocystamine. 1 g of Chelex resin particles dispersed in 10 ml of MES buffer (25 mM, pH 6.7) is incubated for 10 min with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC or EDAC, 400 mg) and N-hydroxysuccinimide (NHS, 70 mg) to activate the carboxyl groups. Then, a selenocystamine (SeCA) solution (SeCA 200 mg in 5 ml MES buffer) is added to the incubated reaction mixture and is subsequently allowed to react for 40 min. Yellowish particles are obtained and further reduced in 20 ml of 0.1M NaBH4 solution to cleave the un-reacted half of the immobilized SeCA species and create selenol groups on the surface of the particles (see
Selenocystamine (SeCA) is immobilized onto a filter paper by reacting the SeCA with dialdehydes created by diol-group oxidation on beta glucose unit as shown in
A small patch (area, 0.125 cm2) of Se-immobilized filter paper (Se—FP) prepared as described in Example 3 can be used for monitoring long term NO generation from a PBS (pH 7.4) solution containing 100 μM GSNO, 500 μM GSH and 0.5 mM EDTA. NO generation/production is measured via chemiluminescence detection. The entire given amount of GSNO is decomposed, NO production ceased in each batch of tests, and the reactions are resumed in a fresh buffer solution containing all components mentioned above (GSNO, GSH AND EDTA) with the same initial concentrations. As shown in
A small patch of Se-immobilized filter paper (Se—FP) prepared as described in Example 3 is mounted on an amperometric NO sensor to detect RSNO species in solution phase as shown in
In ambient conditions, Se-compounds including selenocystamine have been shown to reduce oxygen at the expense of GSH with production of H2O2, as an intermediate of oxygen reduction. Since, however, H2O2 is a potential interfering molecule for the given configuration of NO sensor, the modified NO sensor's performance is tested by increasing GSH concentration in the absence of GSNO.
Compound 2 (see
Selenium groups may be anchored onto the fumed silica surface using amine-containing silylating reagents (e.g., 3-bromopropyl rimethoxy silane) via a two step synthesis as shown in
Nitric oxide production is measured from the particles of Example 9 via chemiluminescence, a direct measurement technique for NO, by soaking the particles in PBS buffer at 37° C. and then adding aliquots of S-nitrosothiol at interval time points. As shown in
A diselenide, 3, 3′ dipropionicdiselenide (SeDPA) is covalently attached to polyethyleneimine (PEI) to create the selenium containing PEI (RSePEI; see
A tube of DM (MWCO, 25 kD) containing 10 mL of 1 wt % RSePEI (derivatized from avg. Mw 25 k PEI) and 0.1 mM EDTA in 0.1 M MOPS buffer (pH 7.9) solution, is first soaked in a solution of this same composition for at least 2 days. After washing with MOPS buffer, the tube of DM is soaked in a glutaraldehyde solution (1 wt %) for 20 min to crosslink the RSePEI species within pore structure of the dialysis membrane. The resulting DM tubing is washed with DI water and subsequently soaked in 10 mM sodium borohydride solution to reduce imine bonds for 1 hour. All reactions are carried out with gentle shaking or stirring. After discharging all solution, the inside/outside of the modified DM (RSePEI-DM) tubing is washed again and stored in 0.1 M phosphate buffer (pH 4.3) until use. Control pieces of DM are prepared with control PEI (no RSe attached), in a similar manner. Small pieces of the tubing walls are cut as needed, and tested for NO generation.
A platinized Pt working electrode (Pt disk (with 250-μm o.d.)) sealed in glass wall tubing and a Ag/AgCl wire as the reference/counter electrode are employed in a gas sensing configuration. The two electrodes are incorporated behind a PTFE gas-permeable membrane (GPM). To create the RSNO sensor to demonstrate NO generation from RSNOs in fresh blood, a piece of RSePEI-DM is affixed on the GPM of the NO sensor using an O-ring, allowing the RSePEI-treated surface to face toward the GPM. Control NO sensors are also prepared with control DM described above (no RSe species). All sensor polarization, calibration and subsequent amperometric measurements are carried out in a standard fashion.
Animal blood is freshly obtained from Extracorporeal Membrane Oxygenation (ECMO) laboratory at the University of Michigan Medical School. Blood samples are heparinized immediately after being obtained by using a concentrated heparin solution (2 U/ml) added at 1:500 volume ratio to the blood (from porcine intestine, Sigma-Aldrich (St. Louis, Mo.)). The resulting blood samples have ACT (activated clotting time) values in the range of 250˜300 seconds, and are kept at 25° C. in the dark and used within 3 hours. To investigate whether exposure to blood plasma affects the NO generating ability of the RSePEI-FP material, platelet-rich plasma is prepared from heparinized porcine blood via centrifugation at 250 g for 15 min. A piece (0.5 cm2) of the RSePEI-FP polymer is stored in the plasma for up to 5 days, and its catalytic NO generation from RSNO species is tested intermittently by NOA measurements after simple washing with DI water. For direct detection of NO generated in rabbit blood using the immobilized RSePEI species, two electrodes, a control NO sensor and a RSNO sensor are employed. Each sensor is first calibrated with respect to its inherent response to NO in PBS buffer. Then, the amperometric signals of both sensors are stabilized at 25° C. with the sensors placed into the same N2-saturated 60 ml PBS (pH 7.4) solution. Finally, 40 ml of the fresh whole blood sample is added to the PBS solution to yield a 40% (v/v) dilution under a N2 atmosphere, and the amperometric responses of each sensor to the sample is monitored.
As illustrated in
To a stirred solution of 2-thiophencarboxylic acid (2.0 g, 15.6 mmol) in THF (200 mL) is added NaH (95%, 0.66 g, 15.7 mmol) at 0° C. After 10 minutes, n-BuLi (2.5 M solution in hexanes, 6.3 mL, 15.7 mmol) is slowly dropped into the above solution and stirred for 10 minutes. The reaction mixture is warmed to RT, then, stirred for 50 minutes. Tellurium (1.9 g, 14.9 mmol) is quickly added into the reaction mixture under a strong stream of nitrogen. After stirring for 2 hours, the mixture is concentrated under a reduced pressure to yield about 20 ml of a reddish brown slurry. The slurry is poured into a solution of DI water (300 mL) and CH2Cl2 (200 mL) at 0° C. while adjusting the pH of solution to approx. 1 using 1.5N HCl. The entire mixture is vigorously mixed by blowing air through it at 0° C. The mixture is filtered to remove an undissolved solid and the filter cake is washed with CH2Cl2. The separated water layer is extracted 2 times more with CH2Cl2. The combined organic layer is dried with anhydrous Na2SO4, filtered and washed with CH2Cl2. The filtrate is concentrated to give a dark reddish solid under a reduced pressure.
The crude residue is triturated with CH2Cl2 (50 mL), then filtered and washed with CH2Cl2 to give a reddish brown solid (0.93 g, 25% yield). Decomposition Temperature 168-172° C.; 1H NMR (500 MHz, DMSO-d6, 25° C.): δ=13.17 (bs, 2H; 2 COOH), 7.54 (d, J=4.5 Hz, 2H; 2 CCH), 7.43 (d, J34.5 Hz, 2H; 2 TeCCH); 13C NMR (125 MHz, DMSO-d6,25° C.): δ=162.28, 142.13, 140.12, 134.53, 106.19; 125TeNMR (MHz, DMSO-d6, 25° C.): δ=497.60; IR (KBr)=3426 cm−1 (COO—H), 2959, 2554 cm−1 (═C—H), 1667 cm−1 (C═O), 1516 cm−1 (C═C), 1422 cm−1 (═C—H); HRMS (EI): m/z: [M]+ calcd. for C10H6O4S2Te2, 513.7832: 513.7835; Anal. Calcd for C10H6O4S2Te2; C, 23.57; H, 1.19; O, 12.56; S, 12.59. Found C, 23.25; H, 1.23; S, 12.28.
A synthetic route to tellurosulfide polymer 7 is depicted in
Aminated Polymer 5:
Polymer 4 (1.86 g) is dissolved in anhydrous DMAC (30 mL), and then is slowly added into a stirred solution of dipropylamine-PEO (10.4 g) in DMAC (12 mL) at 40° C. for 3 hours. The mixture is stirred for 1 day at 40° C., and then is slowly added into Et2O (400 mL). The yellowish polymer formed is filtered and washed with Et2O (600 mL). The filter cake is soxhlet extracted with MeOH for 2 days. After cooling to RT, the solid cake is again washed with MeOH, then dried by vacuum pump for 2 days to yield polymer 5 (0.82 g). A solution of aminated polymer 5 in DMAC is titrated by a calorimetric method using bromophenol blue and p-toluenesulfonic acid in isopropanol (0.2 mmole of amine sites/g of polymer 5). IR (film on NaCl)=3323 cm−1 (N—H), 2916, 2857 cm−1 (CH2), 1715 cm−1 (C═O), 1614 cm−1 (HNCONH), 1529 cm−1 (C—N, N—H), 1102 cm−1 (CH2—O—CH2)
Ditelluride Polymer 6:
DTDTCA 2 (17 mg, 33 Vmole) solution in THF (5 mtL) is mixed with EDC.HCl (15 mg, 78 μmole) in DI water (5 mL). The cloudy mixture is stirred and became clear by adding Et3N (20 mg, 198 μmole). Then, NHS (9 mg, 78 μmole) is added into the mixture at RT. Aminated polymer 5 (0.34 g, 68 μmole of free amine) solution in THF (12 mL) is then mixed with the above solution and stirred at RT overnight. The mixture is slowly added into Et2O (900 mL) to form a slightly reddish yellow polymer. The solid is washed with Et2O and DI water. The filter cake is stirred in MeOH at RT overnight. The residue is again filtered and washed with MeOH, and then is dried with a vacuum pump to give a yellowish polymer 6 (0.2 g). IR (film on NaCl)=3320 cm−1 (N—H), 2915, 2849 cm−1 (CH2), 1715 cm−1 (C═O), 1616 cm−1 (HNCONH), 1526 cm−1 (C—N, N—H), 1445 cm−1 (═C—H), 1099 cm−1 (CH2—O—CH2).
Tellurosulfide Polymer 7:
A small film of polymer 6 (3.92 mg; size, 0.9 cm×1.8 cm; thickness, 2.4 μm) is soaked in the solution of GSHI/GSNO (glutathione/s-nitrosoglutathione) (100 μM/100 μM) in 10 mL of PBS buffer (10 mM), pH 7.4 containing 0.5 mM EDTA (the same PBS buffer used unless otherwise noted). After the mixture is shaken overnight at RT, the film is taken out from the mixture. This film is again shaken in a fresh solution of GSH/GSNO (200 μM/200 μM) in 10 mL of PBS buffer for 6 hours. The film is removed from the solution and then put into a fresh solution of 10 mL PBS buffer. The same procedure to wash the film is operated a couple of times to give a film of desired polymer 7 as a hydrated state right before using in NOA experiments. IR (film on NaCl)=3326 cm−1 (N—H), 2923, 2859 cm−1 (CH2), 1716 cm−1 (C═O), 1662 cm−1 (C═O from GSH), 1615 cm−1 (HNCONH), 1531 cm−1 (C—N, N—H), 1450 cm−1 (—C—H), 1249 cm−1 (CH2 from GSH), 1108 cm−1 (CH2—O—CH2).
As shown in
Synthesis of PAA-Te 2 (see Scheme 1 (A),
Synthesis of hydrogel 4 (see Scheme 1 (
As shown in
NO generation of blank hydrogel 4 from GSNO and GSH. To ensure that the NO generation is induced only from organotelluride, not the polymer backbone itself, a blank hydrogel 4 is investigated for catalytic NO generation from GSNO and GSH in deoxygenated PBS buffer (pH 7.4, containing 0.5 mM EDTA) (see
All publications and patents mentioned herein, including those items listed below, are hereby incorporated by reference in their entirety as if each individual publication or patent was specifically and individually indicated to be incorporated by reference. In case of conflict, the present application, including any definitions herein, will control. To the extent that any U.S. Provisional Patent Applications to which this patent application claims priority incorporate by reference another U.S. Provisional Patent Application, such other U.S. Provisional Patent Application is not incorporated by reference herein unless this patent application expressly incorporates by reference, or claims priority to, such other U.S. Provisional Patent Application.
Also incorporated by reference herein in its entirety is U.S. Patent Publication No. 2003/0044546.
Contemplated equivalents of the chalcogenide compound, coating and compositions described above include such materials which otherwise correspond thereto, and which have the same general properties thereof (e.g., biocompatible, nitric oxide generating), wherein one or more simple variations of substituents are made which do not adversely affect the efficacy of such molecule to achieve its intended purpose. In general, the compounds of the present disclosure may be prepared by the methods illustrated in the general reaction schemes as, for example, described herein, or by modifications thereof, using readily available starting materials, reagents and conventional synthesis procedures. In these reactions, it is also possible to make use of variants which are in themselves known, but are not mentioned here.
The present disclosure provides among other things, coatings, compositions, devices, and methods. While specific embodiments of the subject disclosure have been discussed, the above specification is illustrative and not restrictive. Many variations of the disclosure will become apparent to those skilled in the art upon review of this specification. The full scope of the disclosure should be determined by reference to the claims, along with their full scope of equivalents, and the specification, along with such variations.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/741,601, filed Dec. 2, 2005, the entire disclosure of which is incorporated by reference herein.
The government has certain rights in the present invention that was made in the course of research partially supported by the National Institutes of Health (NIH), Grant Nos. EB-000783 and EB004527.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2006/046013 | 12/1/2006 | WO | 00 | 3/11/2009 |
| Number | Date | Country | |
|---|---|---|---|
| 60741601 | Dec 2005 | US |
