WO2000019976A9 - Biodegradable terephthalate polyester-poly(phosphonate) and polyester-poly(phosphite) compositions, articles, and methods of using them - Google Patents
Biodegradable terephthalate polyester-poly(phosphonate) and polyester-poly(phosphite) compositions, articles, and methods of using themInfo
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- WO2000019976A9 WO2000019976A9 PCT/US1999/022898 US9922898W WO0019976A9 WO 2000019976 A9 WO2000019976 A9 WO 2000019976A9 US 9922898 W US9922898 W US 9922898W WO 0019976 A9 WO0019976 A9 WO 0019976A9
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/68—Polyesters containing atoms other than carbon, hydrogen and oxygen
- C08G63/692—Polyesters containing atoms other than carbon, hydrogen and oxygen containing phosphorus
- C08G63/6924—Polyesters containing atoms other than carbon, hydrogen and oxygen containing phosphorus derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/6926—Dicarboxylic acids and dihydroxy compounds
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K9/00—Medicinal preparations characterised by special physical form
- A61K9/14—Particulate form, e.g. powders, Processes for size reducing of pure drugs or the resulting products, Pure drug nanoparticles
- A61K9/16—Agglomerates; Granulates; Microbeadlets ; Microspheres; Pellets; Solid products obtained by spray drying, spray freeze drying, spray congealing,(multiple) emulsion solvent evaporation or extraction
- A61K9/1605—Excipients; Inactive ingredients
- A61K9/1629—Organic macromolecular compounds
- A61K9/1641—Organic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyethylene glycol, poloxamers
- A61K9/1647—Polyesters, e.g. poly(lactide-co-glycolide)
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L17/00—Materials for surgical sutures or for ligaturing blood vessels ; Materials for prostheses or catheters
- A61L17/06—At least partially resorbable materials
- A61L17/10—At least partially resorbable materials containing macromolecular materials
- A61L17/105—Polyesters not covered by A61L17/12
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L24/00—Surgical adhesives or cements; Adhesives for colostomy devices
- A61L24/04—Surgical adhesives or cements; Adhesives for colostomy devices containing macromolecular materials
- A61L24/046—Surgical adhesives or cements; Adhesives for colostomy devices containing macromolecular materials obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
- A61L31/04—Macromolecular materials
- A61L31/06—Macromolecular materials obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P29/00—Non-central analgesic, antipyretic or antiinflammatory agents, e.g. antirheumatic agents; Non-steroidal antiinflammatory drugs [NSAID]
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
- A61P31/04—Antibacterial agents
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
- A61P31/12—Antivirals
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P35/00—Antineoplastic agents
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P7/00—Drugs for disorders of the blood or the extracellular fluid
- A61P7/02—Antithrombotic agents; Anticoagulants; Platelet aggregation inhibitors
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K9/00—Medicinal preparations characterised by special physical form
- A61K9/0012—Galenical forms characterised by the site of application
- A61K9/0019—Injectable compositions; Intramuscular, intravenous, arterial, subcutaneous administration; Compositions to be administered through the skin in an invasive manner
- A61K9/0024—Solid, semi-solid or solidifying implants, which are implanted or injected in body tissue
Definitions
- the invention relates to biodegradable homopolymer and block copolymer 5 compositions, in particular those containing both phosphite and terephthalate ester linkages, or both phosphonate and terephthalate ester linkages in the polymer backbone, which degrade /// vivo into non-toxic residues
- the copolymers of the invention are particularly useful as essentially non-osteoconductive, non-porous, implantable medical devices and drug delivery systems 0
- Biocompatible polymeric materials have been used extensively in therapeutic drug delivery and medical implant device applications Sometimes, it is also desirable for such polymers to be, not only biocompatible, but also biodegradable to obviate the need for 5 removing the polymer once its therapeutic value has been exhausted
- a biodegradable medical device is intended for use as a drug delivery or other controlled release system
- using a polymeric carrier is one effective means to deliver the 5 therapeutic agent locally and in a controlled fashion, see Langer et al , "Chemical and Physical Structures of Polymers as Carriers for Controlled Release of Bioactive Agents", J. Macro. Science, Rev. Macro. Chem. Phys., C23.
- the steps leading to release of the therapeutic agent are water diffusion into the matrix, dissolution of the therapeutic agent, and diffusion of the therapeutic agent out through the channels of the matrix
- the mean residence time of the therapeutic agent existing in the soluble state is longer for a non-biodegradable matrix than for a biodegradable matrix, for which passage through the channels of the matrix, while it may occur, is no longer required Since many pharmaceuticals have short half-lives, therapeutic agents can decompose or become inactivated within the non-biodegradable matrix before they are released
- polyesters Patent et al , "Biodegradable Drug Delivery Systems Based on Alipathic Polyesters Application to Contraceptives and Narcotic Antagonists," Controlled Release o/Bioactive Materials, 1 -44 (Richard Baker ed , 1980), poly(amino acids) and pseudo-poly(amino acids) (Pulapura et al , "Trends in the Development of Bioresorbable Polymers for Medical Applications," J.
- biodegradable materials that are used as medical implant materials are polylactide, polyglycolide, polydioxanone, poly(lactide-co-glycolide), poly(glycolide-co-polydioxanone), polyanhydrides, poly(glycolide-co-trimethylene carbonate), and poly(glycolide-co-caprolactone).
- injectable polyphosphazenes have also been described as useful for forming solid biodegradable implants / ' /; situ. See, Dunn et al., in U.S. Patent Nos. 5,340,849; 5,324,519; 5,278,202; and 5,278,201.
- Polymers having phosphoester linkages called poly(phosphates), poly(phosphonates) and poly(phosphites), are known. See Penczek et al., Handbook of
- the phosphorus adds versatility to the polymers by allowing a multiplicity of reactions. Bonding to phosphorus can involve the 3p orbitals or various 3s-3p hybrids; spd hybrids are also possible because of the accessible d orbitals. Thus, the physico-chemical properties of the poly(phosphoesters) can be readily changed by varying either the R or R' group.
- the biodegradabihty of the polymer is due primarily to the physiologically labile phosphoester bond in the backbone of the polymer. By manipulating the backbone or the side chain, a wide range of biodegradation rates are attainable.
- poly(phosphoesters) An additional feature of poly(phosphoesters) is the availability of functional side groups. Because phosphorus can be pentavalent, drug molecules or other biologically active substances can be chemically linked to the polymer, as well as physically dissolved in the polymer, prior to shaping the polymer into its final form. For example, drugs with - O-carboxy groups may be coupled to the phosphorus via an ester bond, which is hydrolyzable.
- the P-O-C group in the polymer backbone also lowers the glass transition temperature of the polymer and, importantly, confers solubility in common organic solvents, which is desirable for easy characterization and processing. Kadiyala et al. at page 35.
- EP 386 757 discloses the use of poly(phosphate) esters as prostheses and therapeutic agent delivery vehicles, recognizing that the polymers are biodegradable because of the hydrolyzable phosphoester bond in the backbone With phosphorous in the trivalent state, the polymers can be polyphosphates or polyphosphonates having the general formula:
- R and R' are organic or organometallic moieties, and n is from about 10 to about
- EP 057 116 discloses biocompatible polyphosphate esters with difunctional oligomers joined by phosphate bridging structures of general formula I:
- OL is an oligomer, preferably chosen from the group comprising polyethylene terephthalate and polybutylene terephthalate; Y and Z are the two functional groups of the oligomer, such as OH; and R can be a substituted or unsubstituted alkyl, aryl or aralkyl group.
- R can be a substituted or unsubstituted alkyl, aryl or aralkyl group.
- Kadiyala et al. discloses loading a biodegradable porous material with bone morphogenic proteins to make a bone graft for large segmental defects. Kadiyala et al. also discloses reacting bis(2-hydroxyethyl) terephthalate with dimethyl phosphite to form the following biodegradable poly(phosphite):
- Lyophilized pellets of a powder of the above polymer were subcutaneously implanted in rats to test soft tissue response and compression molded bone plugs were implanted in rabbits. No inflammatory response was observed. However, the polymer underwent very rapid breakdown and structural rigidity was lost.
- the corresponding terephthalate poly(phosphate) materials have been described as biodegradable materials in WO 98/44021 (U.S. Serial No. 09/053,648, filed April 2, 1998).
- Lo discloses using the above biodegradable poly(phosphite), poly[bis(2-ethoxy) hydrophosphonic terephthalate] (PPET), as a biodegradable, macroporous structure and suggests uses in bone graft applications. Bone implant studies were said to suggest good body tolerance of the material. However, no formation of new bone was observed, possibly due to the rapid in vivo degradation rate. Hungnan Lo, "Synthesis of Biodegradable Polymers and Porous Grafts for Orthopedic Applications" (Ph.D. dissertation 1995, The Johns Hopkins University, Baltimore, MD).
- R is a divalent organic moiety; x is ⁇ 1; n is 3-7,500; and
- R' is hydrogen, an aliphatic, aromatic, or heterocyclic residue.
- the compositions or devices can advantageously comprise at least one biologically active substance.
- the biodegradable polymer is sufficiently pure to be biocompatible and is capable of forming biocompatible residues upon biodegradation.
- the invention comprises essentially non-osteoconductive medical or drug delivery devices comprising the above described polymer, especially where R' is hydrogen.
- the device of the invention is non-porous and adapted for implantation or injection into the body of an animal.
- variable groups can be more specifically defined.
- R in formula I is an alkylene group, a cycloaliphatic group, a phenylene group, or comprises a divalent group having the formula:
- R is oxygen, nitrogen, or sulfur and m is 1 to 3.
- R can also be an alkylene group, having from 1 to 7 carbon atoms, or an ethylene group.
- the R' in formula I can preferably be an alkyl group, a phenyl group, an alkyl group having from 1 to 7 carbon atoms, an ethyl group.
- the x in formula I can preferably be from about 1 to about 30, or from about 1 to about 20, or from about 2 to 20.
- the copolymer is prepared by solution polymerization or can comprise additional biocompatible monomeric units. Additionally, the copolymer can be soluble in at least one of the solvents selected from the group consisting of acetone, dichloromethane, chloroform, ethyl acetate, DMAC, N-methyl pyrrolidone, dimethylformamide and dimethylsulfoxide.
- the biologically active substance can preferably be is selected from the group consisting of peptides, polypeptides, proteins, amino acids, polysaccharides, growth factors, hormones, anti-angiogenesis factors, interferons, or cytokines, and pro-drugs of these substances.
- the biologically active substance can also be a therapeutic drug or pro- drug, such as any anti-neoplastic agent, antibiotic, anti-viral agent, antifungal agent, anti- inflammatory agent, anticoagulant, or pro-drugs of these substances.
- the biologically active substance is paclitaxel.
- the biologically active substance and the copolymer can form a homogenous matrix or the biologically active substance can be encapsulated within the copolymer.
- compositions, device, or method of using them can also be characterized by a release rate of the biologically active substance in vivo.
- the release rate can be partially controlled by the hydrolysis of the phosphoester bond of the polymer upon biodegradation
- compositions, device, or method of using them can also be adapted for implantation or injection into the body of an animal
- the composition selected results in minimal tissue irritation when implanted or injected into vasculated tissue.
- compositions, device, or them of using them will employ them as capable of being a biosorbable suture, an orthopedic appliance, or a bone cement bone wax for repairing injuries to bones and connective tissue Alternatively, they will employ a laminate for use as a degradable or non-degradable fabric, or they can be fabricated as a tube for nerve regeneration.
- the composition or device is implantable and comprises a coating comprising the polymer of formula I.
- the copolymer can also be used as a coating on other structures or as a barrier for adhesion prevention on implantable or injectable compositions or devices
- the composition or device comprising a polymer of formula I can be used in methods to deliver at least one biologically active substance, such as one or more of the biologically active substances noted above.
- at least one biologically active substance such as one or more of the biologically active substances noted above.
- the invention specifically includes a method for the controlled release of at least one biologically active substance comprising the steps of (a) combining one or more biologically active substances with a biodegradable terephthalate polymer having the recurring monomeric units shown in formula I to form an admixture;
- Figure 1 shows a GPC chromatogram for poly(BHET-EP) as prepared in Example 2A.
- Figure 2 shows a GPC chromatogram for poly(BHET-EP/TC) as prepared in
- aliphatic refers to a linear, branched, or cyclic alkane, alkene, or alkyne.
- Preferred aliphatic groups in the polymers of the invention are linear or branched alkanes having from 1 to 10 carbons, preferably being linear alkane groups of 1 to 7 carbon atoms.
- aromatic refers to an unsaturated cyclic carbon compound with 4n+2 ⁇ electrons.
- heterocyclic refers to a saturated or unsaturated ring compound having one or more atoms other than carbon in the ring, for example, nitrogen, oxygen or sulfur.
- biodegradable terephthalate copolymer composition of the invention comprises the recurring monomeric units as shown in formula I:
- R is a divalent organic moiety.
- R can be any divalent organic moiety so long as it does not interfere with the polymerization, copolymerization, or biodegradation reactions of the copolymer.
- R can be an aliphatic group, for example, alkylene, such as ethylene, 1 , 2-dimethylethylene, n-propylene, isopropylene, 2-methylpropylene, 2,2- dimethylpropylene or tert-butylene, tert-pentylene, n-hexylene, n-heptylene and the like; alkenylene, such as ethenylene, propenylene, dodecenylene, and the like; alkynylene, such as propynylene, hexynylene, octadecynylene, and the like; an aliphatic group substituted with a non-interfering substituent, for example, hydroxy-, halogen- or nitrogen-substitute
- R can also be a divalent aromatic group, such as phenylene, benzylene, naphthalene, phenanthrenylene, and the like, or a divalent aromatic group substituted with a non-interfering substituent.
- R can also be a divalent heterocyclic group, such as pyrrolylene, furanylene, thiophenylene, alkylene-pyrrolylene-alkylene, pyridylene, pyridinylene, pyrimidinylene and the like, or may be any of these substituted with a non- interfering substituent.
- R is an alkylene group, a cycloaliphatic group, a phenylene group, or a divalent group having the formula.
- R is oxygen, nitrogen, or sulfur, and m is 1 to 3. More preferably, R is an alkylene group having from 1 to 7 carbon atoms and, most preferably, R is an ethylene group.
- R' in the polymer of the invention is hydrogen, an aliphatic, aromatic or heterocyclic residue. When R' is aliphatic, it is preferably: alkyl, such as methyl, ethyl, n- propyl, i-propyl, n-butyl, tert-butyl, -C 8 H ⁇ , and the like; or alkyl substituted with a non- interfering substituent, such as a halogen, alkoxy or nitro.
- R' When R' is aromatic, it typically contains from about 5 to about 14 carbon atoms, preferably about 5 to 12 carbon atoms and, optionally, can contain one or more rings that are fused to each other. Examples of particularly suitable aromatic groups include phenyl, naphthyl, anthracenyl, phenanthrenyl and the like. When R' is heterocyclic, it typically contains from about 5 to 14 ring atoms, preferably from about 5 to 12 ring atoms, and one or more heteroatoms.
- heterocyclic groups include furan, thiophene, pyrrole, isopyrrole, 3-isopyrrole, pyrazole, 2-isoimidazole, 1,2,3-triazole, 1,2,4-triazole, oxazole, thiazole, isothiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3,4- oxatriazole, 1,2,3,5-oxatriazole, 1,2,3-dioxazole, 1,2,4-dioxazole, 1,3,2-dioxazole, 1,3,4- dioxazole, 1,2,5-oxatriazole, 1,3-oxathiole, 1,2-pyran, 1,4-pyran, 1,2-pyrone, 1,4-pyrone, 1,2-dioxin, 1,3-dioxin, pyridine, N-alkyl
- R' is heterocyclic, it is selected from the group consisting of furan, pyridine, N-alkyl-pyridine, 1,2,3- and 1,2,4-triazoles, indene, anthra-cene and purine.
- R' is hydrogen or an alkyl group or a phenyl group and, even more preferably, an alkyl group having from 1 to 7 carbon atoms. Most preferably, R' is an ethyl group.
- x can vary depending on the desired solubility of the polymer, the desired Tg, the desired stability of the polymer, the desired stiffness of the final polymers, and the biodegradability and the release characteristics desired in the polymer.
- x generally is > 1 and, typically, varies between 1 and 40.
- x is from about 1 to about 30, more preferably, from about 1 to about 20 and, most preferably, from about 2 to about 20
- Feed ratios of the reactants can easily vary from 99 1 to 1 99, for example, 95 5, 90 10, 85 15, 80 20, 75 25, 70 30, 65 35, 60 40, 55 45, 50 50, 45 55, 20 80, 15 85, and the like
- the feed ratio between the dialkyl phosphite reactant and the diol reactant varies from about 90 10 to about 50 50, even more preferably, from about 85 15 to about 50 50, and most preferably, from about 80 20 to about 50 50 Similarly, in the case of making the polymer
- feed ratios of the ethyl phosphonic dichloride "x" reactant (“EP”) can be used with the terephthaloyl chloride reactant (“TC")
- Feed ratios of EP to TC can easily vary from 99 1 to 1 99, for example, 95 5, 90 10, 85 15, 80 20, 75 25, 70 30, 65 35, 60 40, 55 45, 50 50, 45 55, 20 80, 15 85, and the like
- the feed ratio between the phosphonic dichloride reactant and the TC reactant varies from about 90 10 to about 50 50, even more preferably, from about 85 15 to about 50 50, and most preferably, from about 80 20 to about 50 50
- n can vary greatly depending on the biodegradability and the release characteristics desired in the polymer, but typically varies from about 3 to 7,500, preferably between 5 and 5,000 More preferably, n is from about 5 to about 300 and most preferably, from about 5 to about 200
- the polymer of the invention can also comprise additional biocompatible monomeric units so long as they do not interfere with the biodegradable characteristics desired Such additional monomeric units may offer even greater flexibility in designing the precise release profile desired for targeted drug delivery or the precise rate of biodegradability desired for structural implants
- additional biocompatible monomers include the recurring units found in polycarbonates, polyorthoesters, polyamides, polyurethanes, poly(iminocarbonates), and polyanhydrides
- Biodegradable polymers differ from non-biodegradable polymers in that they can be degraded during in vivo therapy This generally involves breaking down the polymer into its monomeric subunits
- the ultimate hydrolytic breakdown products of a poly(phosph ⁇ te) are phosphite, alcohol, and diol, all of which are potentially non-toxic
- the intermediate oligomeric products of the hydrolysis may have different properties, but the toxicology of a biodegradable polymer intended for implantation or injection, even one synthesized from apparently innocuous monomeric structures, is typically determined after one or more in vitro toxicity analyses
- biodegradable polymer composition of the invention is preferably sufficiently pure to be biocompatible itself and remains biocompatible upon biodegradation
- biocompatible is meant that the biodegradation products or the polymer are non-toxic and result in only minimal tissue irritation when implanted or injected into vasculated tissue
- the polymer of the invention is preferably soluble in one or more common organic solvents for ease of fabrication and processing
- Common organic solvents include such solvents as chloroform, dichloromethane, acetone, ethyl acetate, DM AC, N-methyl pyrrolidone, dimethylformamide, and dimethyl-sulfoxide
- the polymer is preferably soluble in at least one of the above solvents
- the glass transition temperature (Tg) of the polymer of the invention can vary widely depending upon the brancing of the diols used to prepare the polymer, the relative proportion of phosphorus-containing monomer used to make the polymer, and the like
- the Tg is within the range of about -10°C to about 100°C and, even more preferably, between about 0 and 50°C Non-Osteoconductivity of the Polymer
- the polymers of the present invention are preferably non-osteoconductive.
- An osteoconductive material is one that facilitates bone growth in an area of the body where osseous growth, rather than soft tissue growth, would be expected.
- osteoconductive material generally acts as a scaffold into which bone filaments grow without the formation of separating fibrous tissue, as often occurs when objects are implanted into the body. For this reason, osteoconductive materials are often porous materials having a pore diameter of at least one-tenth of a millimeter (100 microns) in width to provide facilitation of tissue and bone growth.
- One method of measuring the pore size and porosity of a material is to record the mercury intrusion volume into a material at different pressures with a Model 30K-A-1 Mercury Porosimeter (Porous Materials, Inc., Ithaca, NY).
- the porosimeter analyzes a material to determine properties such as the pore surface area, total pore volume and mean pores size.
- the porosimeter is able to measure pores ranging in size from 35
- the pore size is an important measurement to consider when determining whether a material is osteoconductive or not.
- the polymer compositions and devices of the present invention may not be osteoconductive and thus need not be porous.
- they are non-porous, have pore diameters of less than 100 microns, or have only a very small number of pore diameters over 100 microns.
- the poly (phosphonate) polymers of the invention do not promote bone growth and, accordingly, need not provide an adequate structure for supporting a network of bone filaments.
- the polymers of the present invention are advantageously suited for controlled rates of biodegradation and concomitant release of biologically active materials.
- Poly(phosphites) can also be obtained by employing tetraalkyldiamides of phosphorous acid as condensing agents, according to the following equation:
- the above polymerization reactions can be either in bulk or solution polymerization.
- An advantage of bulk polycondensation is that it avoids the use of solvents and large amounts of other additives, thus making purification more straightforward. It can also provide polymers of reasonably high molecular weight. Somewhat rigorous conditions, however, are often required and can lead to chain acidolysis (or hydrolysis if water is present). Unwanted, thermally induced side reactions, such as cross-linking reactions, can also occur if the polymer backbone is susceptible to hydrogen atom abstraction or oxidation with subsequent macroradical recombination. To minimize these side reactions, the polymerization is preferably carried out in solution.
- Solution polycondensation requires that both the diol and the phosphorus component be soluble in a common solvent.
- a chlorinated organic solvent such as chloroform, dichloromethane, or dichloroethane.
- the solution polymerization is preferably run in the presence of equimolar amounts of the reactants and a stoichiometric amount of an acid acceptor, usually a tertiary amine such as pyridine or triethylamine.
- the product is then typically isolated from the solution by precipitation with a non-solvent and purified to remove the hydrochloride salt by conventional techniques known to those of ordinary skill in the art, such as by washing with an aqueous acidic solution, e.g., dilute HCl.
- Reaction times tend to be longer with solution polymerization than with bulk polymerization
- aqueous acidic solution e.g., dilute HCl.
- Reaction times tend to be longer with solution polymerization than with bulk polymerization
- side reactions are minimized, and more sensitive functional groups can be incorporated into the polymer
- the disadvantages of solution polymerization are that the attainment of high molecular weights, such as a Mw greater than 20,000, is less likely
- Interfacial polycondensation can be used when high molecular weight polymers are desired at high reaction rates Mild conditions minimize side reactions. Also the dependence of high molecular weight on stoichiometric equivalence between diol and phosphite inherent in solution methods is removed However, hydrolysis of the acid chloride may occur in the alkaline aqueous phase Phase transfer catalysts, such as crown ethers or tertiary ammonium chloride, can be used to bring the ionized diol to the interface to facilitate the polycondensation reaction The yield and molecular weight of the resulting polymer after interfacial polycondensation are affected by reaction time, molar ratio of the monomers, volume ratio of the immiscible solvents, the type of acid acceptor, and the type and concentration of the phase transfer catalyst
- the polymer of formula 1, whether a homopolymer or a block polymer, is isolated from the reaction mixture by conventional techniques, such as by precipitating out, extraction with an immiscible solvent, evaporation, filtration, crystallization and the like Typically, however, the polymer of formula I is both isolated and purified by quenching a solution of said polymer with a non-solvent or a partial solvent, such as diethyl ether or petroleum ether
- a Friedel-Crafts reaction can also be used to synthesize poly(phosphonates)
- Polymerization typically is effected by reacting either bis(chloro-methyl) compounds with aromatic hydrocarbons or chloromethylated diphenyl ether with triaryl phosphonates
- Poly(phosphonates) can also be obtained by bulk condensation between phosphorus diimidazolides and aromatic diols, such as resorcinol and quinoline, usually under nitrogen or some other inert gas
- An advantage of bulk polycondensation is that it avoids the use of solvents and large amounts of other additives, thus making purification more straightforward It can also provide polymers of reasonably high molecular weight Somewhat rigorous conditions, however, are often required and can lead to chain acidolysis (or hydrolysis if water is present) Unwanted, thermally induced side reactions, such as cross-linking reactions, can also occur if the polymer backbone is susceptible to hydrogen atom abstraction or oxidation with subsequent macroradical recombination To minimize these side reactions, the polymerization is preferably carried out in solution Solution polycondensation requires that both the diol and the phosphorus component be soluble in a common solvent Typically, a chlorinated organic solvent is used, such as chloroform, dichloromethane, or dichloroethane The solution polymerization is preferably run in the presence of equimolar amounts of the reactants and a stoichiometric amount of an acid acceptor, usually a tertiary amine such as pyr
- Interfacial polycondensation can be used when high molecular weight polymers are desired at high reaction rates Mild conditions minimize side reactions Also the dependence of high molecular weight on stoichiometric equivalence between diol and dichloride inherent in solution methods is removed However, hydrolysis of the acid chloride may occur in the alkaline aqueous phase. Sensitive dichlorides that have some solubility in water are generally subject to hydrolysis rather than polymerization. Phase transfer catalysts, such as crown ethers or tertiary ammonium chloride, can be used to bring the ionized diol to the interface to facilitate the polycondensation reaction.
- Phase transfer catalysts such as crown ethers or tertiary ammonium chloride
- the yield and molecular weight of the resulting polymer after interfacial polycondensation are affected by reaction time, molar ratio of the monomers, volume ratio of the immiscible solvents, the type of acid acceptor, and the type and concentration of the phase transfer catalyst.
- the biodegradable terephthalate polymer of formula I can be produced by a method comprising the steps of polymerizing p moles of a diol compound having formula II:
- R 2 is H, Cl, halide, or an organic moiety, wherein R' is defined as above, and p>q, to form q moles of a polymer of formula IV, as shown below:
- R, R' and x are as defined above.
- the polymer so formed can be isolated, purified and used as is. Alternatively, the polymer, isolated or not, can be used to prepare a copolymer composition of the invention by:
- the function of the polymerization reaction of step (a) is to phosphorylate the diester starting material and then to polymerize it to form the polymer.
- the polymerization step (a) can take place at widely varying temperatures, depending upon the solvent used, the solubility desired, the molecular weight desired and the susceptibility of the reactants to form side reactions. Preferably, however, the polymerization step (a) takes place at a temperature from about -40 to about +160°C for solution polymerization, preferably from about 0 to 65°C; in bulk, temperatures in the range of about +150°C are generally used.
- the time required for the polymerization step (a) also can vary widely, depending on the type of polymerization being used and the molecular weight desired. Preferably, however, the polymerization step (a) takes place during a time between about 30 minutes and 24 hours. While the polymerization step (a) may be in bulk, in solution, by interfacial polycondensation, or any other convenient method of polymerization, preferably, the polymerization step (a) is a solution polymerization reaction Particularly when solution polymerization reaction is used, an acid acceptor is advantageously present during the polymerization step (a)
- a particularly suitable class of acid acceptor comprises tertiary amines, such as pyridine, trimethylamine, triethylamine, substituted anilines and substituted aminopyridines The most preferred acid acceptor is the substituted aminopyridine 4-dimethyl-aminopyridine ("DMAP")
- the addition sequence for the polymerization step (a) can vary significantly depending upon the relative reactivities of the diol of formula II, the phosphonic dichloride of formula III, and the polymer of formula IV, the purity of these reactants, the temperature at which the polymerization reaction is performed, the degree of agitation used in the polymerization reaction, and the like
- the diol of formula II is combined with a solvent and an acid acceptor, and then the phosphonic dichloride is added slowly
- a solution of the phosphonic dichloride in a solvent may be trickled in or added dropwise to the chilled reaction mixture of diol, solvent and acid acceptor, to control the rate of the polymerization reaction
- step (b) The purpose of the copolymerization of step (b) is to form a copolymer comprising (i) the phosphorylated polymer chains produced as a result of polymerization step (a) and (ii) interconnecting polyester units The result is a copolymer having a microcrystalline structure particularly well suited to use as a controlled release medium
- the copolymerization step (b) of the invention usually takes place at a slightly higher temperature than the temperature of the polymerization step (a), but also may vary widely, depending upon the type of copolymerization reaction used, the presence of one or more catalysts, the molecular weight desired, the solubility desired, and the susceptibility of the reactants to undesirable side reaction
- the copolymerization step (b) when carried out as a solution polymerization reaction, it typically takes place at a temperature between about -40 and 100°C
- Typical solvents include methylene chloride, chloroform, or any of a wide variety of inert organic solvents
- the time required for the copolymerization of step (b) can also vary widely, depending on the molecular weight of the material desired and, in general, the need to use more or less rigorous conditions for the reaction to proceed to the desired degree of completion. Typically, however, the copolymerization step (b) takes place during a time of about 30 minutes to 24 hours.
- step (b) The time required for the copolymerization of step (b) can also vary widely, depending on the molecular weight of the material desired and, in general, the need to use more or less rigorous conditions for the reaction to proceed to the desired degree of completion. Typically, however, the co-polymerization step (b) takes place during a time of about 30 minutes to 24 hours.
- the addition sequence of the reactive chlorides and the reaction temperatures in each step are preferably optimized to obtain the combination of molecular weight desired with good solubility in common organic solvents.
- the additive sequence comprises dissolving the bis-terephthalate starting material with an acid acceptor in a solvent in which both are soluble, chilling the solution with stirring, slowly adding an equal molar amount of the phosphonic dichloride (dissolved in the same solvent) to the solution, allowing the reaction to proceed at room temperature for a period of time, slowly adding an appropriate amount of terephthaloyl chloride, which is also dissolved in the same solvent, and increasing the temperature to about 50°C before refluxing overnight.
- the polymer of formula I whether a homopolymer, block copolymer, or other copolymer is isolated from the reaction mixture by conventional techniques, such as by precipitating out, extraction with an immiscible solvent, evaporation, filtration, crystallization and the like.
- the polymer of formula I is both isolated and purified by quenching a solution of said polymer with a non-solvent or a partial solvent, such as diethyl ether or petroleum ether.
- the lifetime of a biodegradable polymer in vivo also depends partly upon its molecular weight, crystallinity, biostability, and the degree of cross-linking. In general, the greater the molecular weight, the higher the degree of crystallinity, and the greater the biostability, the slower biodegradation will be.
- the structure of the side chain can influence the release behavior of the polymer and biodegradability.
- these classes of poly(phosphoesters) conversion of the phosphorus side chain to a more lipophilic, more hydrophobic or bulky group would slow down the degradation process.
- release would usually be faster from copolymer compositions with a small aliphatic group side chain than with a bulky aromatic side chain.
- the terephthalate poly(phosphites) and poly(phosphonates)of formula I are usually characterized by a release rate of the biologically active substance in vivo that is controlled at least in part as a function of hydrolysis of the phosphoester bond of the polymer during biodegradation.
- poly(phosphites) do not have a side chain that can be manipulated to influence the rate of biodegradation. Therefore, it has been somewhat surprising to discover that the lifetime of a biodegradable terephthalate poly(phosphite) polymer in vivo depends sufficiently upon its molecular weight, crystallinity, biostability, and the degree of cross-linking to still achieve acceptable degradation rates. In general, the greater the molecular weight, the higher the degree of crystallinity, and the greater the biostability, the slower biodegradation will be.
- the polymer of formula I is preferably used as a composition containing, in addition to the polymer, a biologically active substance to form a variety of useful biodegradable materials.
- the polymer of formula I can be used as a medical device in the form of a biosorbable suture, an orthopedic appliance or bone cement for repairing injuries to bone or connective tissue, a laminate for degradable or non-degradable fabrics, or a coating for an implantable device, even without the presence of a biologically active substance.
- the biodegradable terephthalate polymer composition comprises:
- the polymer of formula I can also be used as a non-osteoconductive, non-porous composition containing, in addition to the polymer, a biologically active substance to form a variety of useful biodegradable materials.
- the biologically active substance of the invention can vary widely with the purpose for the composition.
- the active substance(s) may be described as a single entity or a combination of entities.
- the delivery system is designed to be used with biologically active substances having high water solubility as well as with those having low water solubility to produce a delivery system that has controlled release rates.
- biologically active substance includes, without limitation, medicaments; vitamins; mineral supplements; substances used for the treatment, prevention, diagnosis, cure or mitigation of disease or illness; or 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.
- Non-limiting examples of broad categories of useful biologically active substances include the following expanded therapeutic categories: anabolic agents, antacids, anti- asthmatic agents, anticholesterolemic and anti-lipid agents, anti-coagulants, anti- convulsants, anti-diarrheals, anti-emetics, anti-infective agents, anti-inflammatory agents, anti-manic agents, anti-nauseants, anti-neoplastic agents, anti-obesity agents, anti-pyretic and analgesic agents, anti-spasmodic agents, anti-thrombotic agents, anti-uricemic agents, anti-anginal agents, antihistamines, anti-tussives, appetite suppressants, biologicals, cerebral dilators, coronary dilators, decongestants, diuretics, diagnostic agents, erythropoietic agents, expectorants, gastrointestinal sedatives, hyperglycemic agents, hypnotics, hypoglycemic agents, ion exchange resins, laxatives,
- useful biologically active substances from the above categories include: (a) anti-neoplasties such as androgen inhibitors, anti-metabolites, cytotoxic agents, and immunomodulators; (b) anti-tussives such a s dextromethorphan, dextromethorphan hydrobromide, noscapine, carbetapentane citrate, and chlophedianol hydrochloride; (c) anti-histamines such as chlorpheniramine maleate, phenindamine tartrate, pyrilamine maleate, doxylamine succinate, and phenyltoloxamine citrate; (d) decongestants such as phenylephrine hydrochloride, phenylpropanolamine hydrochloride, pseudoephedrine hydrochloride, and ephedrine; (e) various alkaloids such as codeine phosphate, codeine sulfate and morphine; (f) mineral supplements such as potassium chloride, zinc
- NSAIDs nonsteroidal anti-inflammatory drugs
- analgesics such as diclofenac, ibuprofen, ketoprofen, and naproxen
- opiate agonist analgesics such as codeine, fentanyl, hydromorphone, and morphine
- saliclate analgesics such as aspirin (ASA) (enteric coated ASA)
- H blocker antihistamines such as clemastine and terfenadine
- H 2 -blocker antihistamines such as cimetidine, famotidine, nizadine, and ranitidine
- anti-infective agents such as mupirocin
- antianaerobic anti-infectives such as chloramphenicol and clindamycin
- antifungal antibiotic anti-infectives such as amphotericin b, clotrimazole
- the following less common drugs may also be used chlorhexidine, estradiol cypionate in oil, estradiol valerate in oil, flurbiprofen, flurbiprofen sodium, ivermectin, levodopa, nafarelin, and somatropin
- the following new drugs may also be used Recombinant beta-glucan, bovine immunoglobulin concentrate, bovine superoxide dismutase, a mixture comprising fluorouracil, epinephrine, and bovine collagen, recombinant hirudin (r-Hir), HIV-1 immunogen, human anti-TAC antibody, recombinant human growth hormone (r-hGH), recombinant human hemoglobin (r-Hb), recombinant human mecasermin (r-IGF-1), recombinant interferon beta- la, lenograstim (G-CSF), olanzapine, recombinant thyroid stimulating hormone (r-TSH), and topotecan
- intravenous products may be used acyclovir sodium, aldesleukin, atenolol, bleomycin sulfate, human calcitonin, salmon calcitonin, carboplatin, carmustine, dactinomycin, daunorubicin HCl, docetaxel, doxorubicin HCl, epoetin alfa, etoposide (VP-16), fluorouracil (5-FU), ganciclovir sodium, gentamicin sulfate, interferon alfa, leuprolide acetate, meperidine HCl, methadone HCl, methotrexate sodium, paclitaxel, ranitidine HCl, vinblastin sulfate, and zidovudine (AZT) Still further, the following listing of peptides, proteins, and other large molecules may also be used, such as interleukins 1 through 18, including mutants and analogues, interferidid
- the biologically active substance is selected from the group consisting of peptides, polypeptides, proteins, amino acids, polysaccharides, growth factors, hormones, anti-angiogenesis factors, interferons or cytokines, and pro-drugs.
- the biologically active substance is a therapeutic drug or pro-drug, most preferably a drug selected from the group consisting of chemotherapeutic agents and other antineoplastics (such as paclitaxel), antibiotics, anti- virals, antifungals, anti-inflammatories, anticoagulants, and pro-drugs of these substances.
- the biologically active substances are used in amounts that are therapeutically effective.
- a biologically active substance While the effective amount of a biologically active substance will depend on the particular material being used, amounts of the biologically active substance from about 1% to about 65% have been easily incorporated into the present delivery systems while achieving controlled release. Lesser amounts may be used to achieve efficacious levels of treatment for certain biologically active substances.
- Pharmaceutically acceptable carriers may be prepared from a wide range of materials. Without being limited thereto, such materials 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.
- a biodegradable therapeutic agent delivery system consists of a dispersion of the therapeutic agent in a polymer matrix.
- the therapeutic agent is typically released as the polymeric matrix biodegrades in vivo into soluble products that can be absorbed by and eventually excreted from the body.
- an article is used for implantation, injection, or otherwise placed totally or partially within the body, the article comprising the biodegradable terephthalate polymer composition of the invention.
- the biologically active substance of the composition and the polymer of the invention may form a homogeneous matrix, or the biologically active substance may be encapsulated in some way within the polymer.
- the biologically active substance 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.
- composition can be used in an essentially non-osteoconductive medical device in the form of a biosorbable suture, a laminate for degradable or non-degradable fabrics, or a coating for an implantable device.
- a biodegradable delivery system for a biologically active substance consists of a physical dispersion of the therapeutic agent in a polymer matrix.
- the therapeutic agent is typically released as the polymeric matrix biodegrades in vivo into soluble products that can be absorbed by and eventually excreted from the body.
- the essentially non-osteoconductive biodegradable composition of the invention is used to make an article useful for implantation, injection, or otherwise being placed totally or partially within the body.
- the biologically active substance of the composition and the polymer of the invention may form a homogeneous matrix, or the biologically active substance may be encapsulated in some way within the polymer.
- the biologically active substance 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.
- the biologically active substance may be sufficiently immiscible in the polymer of the invention that it is dispersed as small droplets, rather than being dissolved, in the polymer. Either form is acceptable, but it is preferred that, regardless of the homogeneity of the composition, the release rate of the biologically active substance in vivo remain controlled, at least partially as a function of hydrolysis of the phosphoester bond of the polymer upon biodegradation.
- the article of the invention is adapted for implantation or injection into the body of an animal. It is particularly important that such an article result in minimal tissue irritation when implanted or injected into vasculated tissue.
- the copolymer compositions of the invention provide a physical form having specific chemical, physical, and mechanical properties sufficient for the application and a composition that degrades in vivo into non-toxic residues.
- Typical structural medical articles include such implants as ventricular shunts, laminates for degradable or nondegradable fabrics, drug-carriers, biosorbable sutures, burn dressings, coatings to be placed on other implant devices, and the like
- the copolymer compositions of the invention provide a physical form having specific chemical, physical, and mechanical properties sufficient for the application and a composition that degrades m vivo into non-toxic residues
- Typical structural medical articles include implants such as orthopedic fixation devices, ventricular shunts, laminates for degradable or nondegradable fabrics, drug- carriers, biosorbable sutures, burn dressings, coatings to be placed on other implant devices, and the like
- composition of the invention may be a bone wax, bone cement or other material useful for repairing bone and connective tissue injuries
- a biodegradable porous material can be loaded with bone morphogenetic proteins to form a bone graft useful for even large segmental defects
- a biodegradable material in the form of woven fabric can be used to promote tissue ingrowth
- the copolymer composition of the invention may be used as a temporary barrier for preventing tissue adhesion, e g , following abdominal surgery
- the presence of a biodegradable supporting matrix can be used to facilitate cell adhesion and proliferation
- the copolymer composition is fabricated as a tube for nerve generation, for example, the tubular article can also serve as a geometric guide for axonal elongation in the direction of functional recovery
- the copolymer composition of the invention provides a polymeric matrix capable of sequestering a biologically active substance and provides predictable, controlled delivery of the substance The polymeric matrix then degrades to non-toxic residues
- Biodegradable medical implant devices and drug delivery products can be prepared in several ways
- the copolymer can be melt processed using conventional extrusion or injection molding techniques, or these products can be prepared by dissolving in an appropriate solvent, followed by formation of the device, and subsequent removal of the solvent by evaporation or extraction
- the polymers may be formed into drug delivery systems of almost any size or shape desired, for example, implantable solid discs or wafers or injectable rods, microspheres, or other microparticles.
- a biological fluid such as blood, internal organ secretions, mucous membranes, cerebrospinal fluid and the like.
- BHET having excellent purity may be prepared according to the
- BHET is also commercially available.
- Poly[bis(2-ethoxy) hydrophosphonic terephthalate] is synthesized by bulk condensation of dimethyl phosphite (DMP) or diethyl phosphite and bis(2-hydroxyethyl) terephthalate (BHET).
- DMP dimethyl phosphite
- BHET bis(2-hydroxyethyl) terephthalate
- 1.0 gram (4 mmol) of BHET is added to a flask fitted with a magnetic stirrer, a thermometer, and a condenser which can be attached to a vacuum line.
- 0.433 gram (4 mmol) of DMP is added to the BHET and a solution of sodium methoxide in methanol is added to raise the basicity of the reaction mixture.
- the higher pH prevents transesterification of the hydroxyl end group of the BHET.
- the mixture is heated at 100°C for 48 hours and then brought to 120°C for 8 hours by application of high vacuum at
- the reaction mixture was gradually heated to reflux conditions with a heating mantle and kept under reflux overnight (about 18 hours). After refluxing overnight, about 25 ml of dichloromethane was distilled off, and the remaining viscous mixture was heated up to about 90°C with an oil bath to produce second-stage polymerization. After two hours, the remaining dichloromethane was vented, and 145 ml of chloroform was added to the flask. The resulting solution was washed three times with a saturated NaCl solution, dried over anhydrous MgSO , and poured into 500 ml of diethyl ether to precipitate the polymer product. The polymer product was collected by filtration and dried in a vacuum oven.
- poly(phosphite) esters of the invention can be prepared by the procedure described in Example 2 above, except that other diols are substituted for the bis(2- hydroxyethyl) terephthalate during the initial polymerization step.
- bis(3- hydroxypropyl) terephthalate, bis (3-hydroxy-2-methyl-propyl) terephthalate, bis(3- hydroxy-2, 2-dimethyl-propyl) terephthalate, and bis( ⁇ -hydroxyhexyl) terephthalate can be used.
- Example 3 A Synthesis of Polv(BHET-EP/TC. 80/20)
- the reaction mixture was allowed to gradually warm up to room temperature and was stirred for half an hour.
- the reaction mixture was then chilled in a dry ice/acetone bath, and 1.5 g of terephthalic chloride (TC) in 15 ml of dichloromethane was added over a 40- minute period
- TC terephthalic chloride
- the reaction mixture was gradually heated to reflux with a heating mantle After refluxing overnight (about 18 hours), about 30 ml of dichloromethane was dis-tilled off
- the remaining viscous mixture was heated up to about 90°C in an oil bath to begin the second-stage polymerization After two hours, the remaining dichloromethane was vented off, and 150 ml of chloroform was added to the flask
- the polymer solution was then washed three times with saturated NaCl solution, dried with anhydrous MgSO 4 , and precipitated into 500 ml of diethyl ether
- the resulting polymer was collected and dried in a vacuum oven
- Microspheres are prepared via a double-emulsion/solvent-extraction method using FlTC-labeled bovine serum albumin (FITC-BSA) as a model protein drug
- FITC-BSA FlTC-labeled bovine serum albumin
- the resulting microspheres are collected via centrifugation at 3000 X g, washed three times with water, and lyophilized Empty microspheres are prepared in the same way except that water is used as the inner aqueous phase
- the resulting microspheres are mostly between 5 and 20 ⁇ m in diameter and generally exhibit a smooth surface morphology It is determined by observation with confocal fluorescence microscopy that the encapsulated FITC-BSA is distributed uniformly within the microspheres
- the loading level of FITC-BSA is determined by assaying for FITC after hydrolyzing the microspheres in a 0 5 N NaOH solution overnight Loading levels are determined by comparison with a standard curve, which is generated by making a series of FITC-BSA solutions in 0 5 N NaOH Protein loading levels of about 1 59 about 25 wt % are readily obtained
- the encapsulation efficiency of FITC-BSA by the microspheres is determined at different loading levels by comparing the quantity of FITC-BSA entrapped with the initial amount in solution via fluorometry Encapsulation efficiencies of about 70 % to almost 100 % can be obtained
- Example 90 can also be prepared by the procedure described above in Example 2 A, except that hexyl phosphonic dichloride (HP) is substituted for the monomer ethyl phosphonic dichloride (EP) during the initial polymerization step
- the feed ratio can be varied
- aqueous solution of 0 5% w/v polyvinyl alcohol (PVA) is prepared in a 600 mL beaker by combining 1 35 g of PA with 270 mL of deionized water The solution is stirred for one hour and filtered
- a copolymer/drug solution is prepared by combining 900 mg of PPET copolymer and 100 mg of lidocaine in 9 mL of methylene chloride and vortex-mixing
- Lidocaine-containing microspheres are also prepared from other poly(phosphite)s by the same process This experiment yields microspheres loaded with about 5 0-5 5% w/w lidocaine
- Example 5 A Preparation of P(BHET-EP/TC.
- Microspheres Encapsulating FITC-BSA Microspheres are prepared via a double-emulsion/solvent-extraction method using FITC-labeled bovine serum albumin (FITC-BSA) as a model protein drug
- FITC-BSA FITC-labeled bovine serum albumin
- One hundred ⁇ L of an FITC-BSA solution (10 mg/mL) are added to a solution of 100 mg of P(BHET- EP/TC, 80/20) in 1 mL of methylene chloride, and emulsified via sonication for 15 seconds on ice
- the resulting emulsion is immediately poured into 5 mL of a vortexing aqueous solution of 1% polyvinyl alcohol (PVA) and 5% NaCl
- PVA polyvinyl alcohol
- the vortexing is maintained for about one minute
- the resulting emulsion is poured into 20 mL of an aqueous solution of 0 3% PVA and 5% Na
- the resulting microspheres are collected via centrifugation at 3000 X g, washed three times with water, and lyophilized Empty microspheres are prepared in the same way except that water is used as the inner aqueous phase
- the resulting microspheres are mostly between 5 and 20 ⁇ m in diameter and generally exhibit a smooth surface morphology It is determined by observation with confocal fluorescence microscopy that the encapsulated FITC-BSA is distributed uniformly within the microspheres
- the loading level of FITC-BSA is determined by assaying for FITC after hydrolyzing the microspheres in a 0 5 N NaOH solution overnight Loading levels are determined by comparison with a standard curve, which is generated by making a series of FITC-BSA solutions in 0 5 N NaOH Protein loading levels of about 1 59 about 25 wt % are readily obtained
- the encapsulation efficiency of FITC-BSA by the microspheres is determined at different loading levels by comparing the quantity of FITC-BSA entrapped with the initial amount in solution via fluorometry Encapsulation efficiencies of about 70 % to almost 100 % can be obtained
- Example 6 In vitro Release Kinetics of Microspheres Prepared from PPET Polymers
- Five mg of PPET microspheres containing FITC-BSA are suspended in one mL of phosphate buffer saline (PBS) at pH 7 4 and placed into a shaker heated to a temperature of about 37°C
- the suspension is spun at 3000 X g for 10 minutes, and 500 ⁇ l samples of the supernatant fluid are withdrawn and replaced with fresh PBS
- the release of FITC-BSA from the microspheres can be followed by measuring the fluorescence intensity of the withdrawn samples at 519 nm Scaling up, about 50 mg of PPET microspheres are suspended in vials containing
- Example 6A Preparation of P(BHDPT-EP/TC. 50/50 ⁇ ) Microspheres Containing Lidocaine
- An aqueous solution of 0 5% w/v polyvinyl alcohol (PVA) is prepared in a 600 mL beaker by combining 1 35 g of PVA with 270 mL of deionized water The solution is stirred for one hour and filtered
- a copolymer/drug solution is prepared by combining 900 mg of P(BHDPT-EP/TC, 50/50) copolymer and 100 mg of lidocaine in 9 mL of methylene chloride and vortex-mixing
- Lidocaine-containing microspheres are also prepared from P(BHDPT-HP/TC, 50/50) by the same process. This experiment yields microspheres loaded with about 5 0- 5.5% w/w lidocaine
- Example 7 In vitro Release Kinetics of Microspheres Prepared from PPET Polymers Approximately 10 mg of PPET microspheres loaded with lidocaine are placed in PBS (0.1 M, pH 7.4) at 37°C on a shaker Samples of the incubation solution are withdrawn periodically, and the amount of lidocaine released into the samples is assayed by HPLC The same process can be followed for testing microspheres prepared from other poly(phosphite)s
- P(BHET-EP/TC, 80/20) microspheres containing FITC-BSA are suspended in one mL of phosphate buffer saline (PBS) at pH 7 4 and placed into a shaker heated to a temperature of about 37°C At various points in time, the suspension is spun at 3000 X g for 10 minutes, and 500 ⁇ l samples of the supernatant fluid are withdrawn and replaced with fresh PBS The release of FITC-BSA from the microspheres can be followed by measuring the fluorescence intensity of the withdrawn samples at 519 nm
- PBS phosphate buffer saline
- P(BHET-EP/TC, 80/20) microspheres are suspended in vials containing 10 mL of phosphate buffer saline (PBS)
- PBS phosphate buffer saline
- the vials are heated in an incubator to a temperature of about 37°C and then shaken at about 220 rpm Samples of the supernatant are withdrawn and replaced at various points in time, and the amount of FITC-BSA released into the samples is analyzed by spectrophotometry at 492 nm The results indicate generally satisfactory release rates
- P(BHET-EP/TC, 80/20) microspheres containing FITC-BSA are suspended in one mL of phosphate buffer saline (PBS) at pH 7 4 and placed into a shaker heated to a temperature of about 37°C At various points in time, the suspension is spun at 3000 X g for 10 minutes, and 500 ⁇ l samples of the supernatant fluid are withdrawn and replaced with fresh PBS The release of FITC-BSA from the microspheres can be followed by measuring the fluorescence intensity of the withdrawn samples at 519 nm
- PBS phosphate buffer saline
- P(BHET-EP/TC, 80/20) microspheres are suspended in vials containing 10 mL of phosphate buffer saline (PBS)
- PBS phosphate buffer saline
- the vials are heated in an incubator to a temperature of about 37°C and then shaken at about 220 rpm Samples of the supernatant are withdrawn and replaced at various points in time, and the amount of FITC-BSA released into the samples is analyzed by spectrophotometry at 492 nm The results indicate generally satisfactory release rates.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU62833/99A AU6283399A (en) | 1998-10-02 | 1999-10-01 | Biodegradable terephthalate polyester-poly(phosphonate) and polyester-poly(phosphite) compositions, articles, and methods of using them |
CA002345240A CA2345240A1 (en) | 1998-10-02 | 1999-10-01 | Biodegradable terephthalate polyester-poly(phosphonate) and polyester-poly(phosphite) compositions, articles, and methods of using them |
JP2000573338A JP2002526396A (en) | 1998-10-02 | 1999-10-01 | Biodegradable terephthalate polyester-polyphosphonate and polyester-polyphosphite compositions, articles, and methods of use thereof |
EP99950106A EP1117441A2 (en) | 1998-10-02 | 1999-10-01 | Biodegradable terephthalate polyester-poly(phosphonate) and polyester-poly(phosphite) compositions, articles, and methods of using them |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/165,375 US6153212A (en) | 1998-10-02 | 1998-10-02 | Biodegradable terephthalate polyester-poly (phosphonate) compositions, articles, and methods of using the same |
US09/165,373 US6419709B1 (en) | 1998-10-02 | 1998-10-02 | Biodegradable terephthalate polyester-poly(Phosphite) compositions, articles, and methods of using the same |
US09/165,375 | 1998-10-02 | ||
US09/165,373 | 1998-10-02 |
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WO2000019976A2 WO2000019976A2 (en) | 2000-04-13 |
WO2000019976A3 WO2000019976A3 (en) | 2000-07-13 |
WO2000019976A9 true WO2000019976A9 (en) | 2000-10-26 |
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PCT/US1999/022898 WO2000019976A2 (en) | 1998-10-02 | 1999-10-01 | Biodegradable terephthalate polyester-poly(phosphonate) and polyester-poly(phosphite) compositions, articles, and methods of using them |
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EP (1) | EP1117441A2 (en) |
JP (1) | JP2002526396A (en) |
AU (1) | AU6283399A (en) |
CA (1) | CA2345240A1 (en) |
WO (1) | WO2000019976A2 (en) |
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WO1999065531A1 (en) | 1998-06-18 | 1999-12-23 | Johns Hopkins University School Of Medicine | Polymers for delivery of nucleic acids |
US6350464B1 (en) | 1999-01-11 | 2002-02-26 | Guilford Pharmaceuticals, Inc. | Methods for treating ovarian cancer, poly (phosphoester) compositions, and biodegradable articles for same |
US6537585B1 (en) | 1999-03-26 | 2003-03-25 | Guilford Pharmaceuticals, Inc. | Methods and compositions for treating solid tumors |
DE10037983B4 (en) * | 2000-08-03 | 2006-04-13 | Stefan Zikeli | Polymer composition and molded articles containing it containing alkaloid |
US6527693B2 (en) | 2001-01-30 | 2003-03-04 | Implant Sciences Corporation | Methods and implants for providing radiation to a patient |
WO2003000776A1 (en) * | 2001-05-14 | 2003-01-03 | Johns Hopkins Singapore Pte Ltd | Biodegradable polyphosphoramidates for controlled release of bioactive substances |
WO2004080502A1 (en) * | 2003-03-10 | 2004-09-23 | Kawasumi Laboratories, Inc. | Antiadhesive material |
MXPA05010450A (en) | 2003-03-31 | 2005-11-04 | Titan Pharmaceuticals Inc | Implantable polymeric device for sustained release of dopamine agonist. |
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WO1998044021A1 (en) * | 1997-04-03 | 1998-10-08 | Guilford Pharmaceuticals Inc. | Biodegradable terephthalate polyester-poly(phosphate) polymers, compositions, articles, and methods for making and using the same |
PL336596A1 (en) * | 1997-04-30 | 2000-07-03 | Guilford Pharm Inc | Biodegradable compositions with polycycloaliphatic phosphoesters, products containing them and methods of using them |
-
1999
- 1999-10-01 EP EP99950106A patent/EP1117441A2/en not_active Withdrawn
- 1999-10-01 CA CA002345240A patent/CA2345240A1/en not_active Abandoned
- 1999-10-01 JP JP2000573338A patent/JP2002526396A/en active Pending
- 1999-10-01 AU AU62833/99A patent/AU6283399A/en not_active Abandoned
- 1999-10-01 WO PCT/US1999/022898 patent/WO2000019976A2/en not_active Application Discontinuation
Also Published As
Publication number | Publication date |
---|---|
JP2002526396A (en) | 2002-08-20 |
AU6283399A (en) | 2000-04-26 |
CA2345240A1 (en) | 2000-04-13 |
WO2000019976A3 (en) | 2000-07-13 |
EP1117441A2 (en) | 2001-07-25 |
WO2000019976A2 (en) | 2000-04-13 |
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