Patent Application
20120299223
The present invention relates to drug-loaded fibers, and more specifically, to small fibers that are used to deliver drugs to target locations within a patient's body.
Fibers have been proposed for a number of medical applications, including for the localized delivery of therapeutic agents within a patient's body. To facilitate such use, polymeric fibers are loaded with drugs and subsequently implanted within a patient to allow for the delivery of the drug over an extended period of time. The manufacture and practical application of such fibers, however, has been limited by their small size and consequent limitations on the amount of drug that can be loaded therein. It can also be difficult to obtain useful and controllable drug release kinetics from such fibers, and to control the placement and subsequent mobility of such fibers within the patient. The use of such fibers has therefore been limited.
In one aspect, the present invention relates to drug-loaded fibers having high drug loading rates and that offer useful and controllable drug release kinetics.
In another aspect, the present invention relates to implants that comprise at least one drug-loaded fiber having a high drug loading rate and that offer useful and controllable drug release kinetics.
In another aspect, the present invention relates to methods of making drug-loaded fibers, and implants made therefrom, that have high drug loading rates and that offer useful and controllable drug release kinetics.
In yet another aspect, the present invention relates to methods of treating patients using the fibers of the present invention. The fibers of the present invention comprise a polymeric material and a drug. The fibers are characterized by a diameter of up to about 20 microns, and the drug located within the fibers is substantially in particulate form. In certain embodiments, the drug makes up at least about 20 weight percent of the fibers. The drug is either substantially insoluble in the polymer and solvent, or the amount of drug in the solution exceeds the solubility limit of the drug within either of the polymer or solvent. In some embodiments, the fibers of the present invention comprise an inner radial portion and an outer radial portion. A drug is located within the inner and/or outer radial portions.
The implants of the present invention are adapted for implantation into a patient's body. Embodiments of the implants of the present invention include one or more individual fibers, or other implant configurations made from one or more fibers such as yarns, ropes, tubes, and patches.
In one embodiment, the fibers of the present invention are made by a coaxial electrospinning process in which at least one solution is electrospun into a fiber. The solution includes a polymer, a solvent, and a drug. The drug is either substantially insoluble in the polymer and solvent, or the amount of drug in the solution exceeds the solubility limit of the drug within either of the polymer or solvent.
a and 1b are schematic representations of side and cross-sectional views of a fiber, in accordance with an embodiment of the present invention.
a and 2b are schematic representations of side and cross-sectional views side and cross-sectional views of a fiber, in accordance with an embodiment of the present invention.
a is a schematic representation of an electrospinning system used to manufacture fibers of the present invention.
b is a schematic representation of a co-axial needle (in cross-section) used in an electrospinning system of the present invention.
a and 5b are scanning electron micrographs of a co-axial fiber having inner and outer radial portions, in accordance with an embodiment of the present invention.
a, 10b, and 10c show yarns including the incorporation of radiopaque marker bands, in accordance with an embodiment of the present invention.
a, 11b, and 11c show ropes of the present invention.
The present invention includes fibers, methods of making such fibers, implants made from such fibers, and methods of treating patients using such fibers. The inventors have found it possible to manufacture small fibers with surprisingly high drug loading rates, and drug release profiles that may be tailored to the specific requirements of numerous medical applications. In addition, the inventors are able to create various implant configurations from the fibers of the present invention to optimize desired drug delivery characteristics and to facilitate appropriate deliverability of the implant to the patient and subsequent implant mobility. As used herein, “drugs” and “therapeutic agents” are used synonymously to include small molecules, biologics, and other active agents used to produce a desired therapeutic effect.
An example of a fiber of the present invention is shown schematically in
Fiber 100 is made from any suitable polymeric, biocompatible material and includes a drug embedded therein. Preferably, fiber 100 is made from a bioabsorbable material such that it degrades in a patient's body over time following implantation. The rate of degradation of the polymer material used to form the fiber 100 may be designed such that it either degrades following delivery of the drug therefrom, or as a means to control the drug delivery rate via the degradation process.
Examples of bioabsorbable materials that are useful in forming the fiber 100 of the present invention include: polyesters, such as poly(ε-caprolactone) (PCL), poly lactic-co-glycolic acid (PLGA), polyglycolic acid, poly(L-lactic acid), poly(DL-lactic acid); copolymers thereof such as poly(lactide-co-ε-caprolactone), poly(glycolide-co-ε-caprolactone), poly(lactide-co-glycolide), copolymers with polyethylene glycol (PEG); branched polyesters, such as poly(glycerol sebacate); poly(propylene fumarate); poly(ether esters) such as polydioxanone; poly(ortho esters); polyanhydrides such as poly(sebacic anhydride); polycarbonates such as poly(trimethylcarbonate) and related copolymers; polyhydroxyalkanoates such as 3-hydroxybutyrate, 3-hydroxyvalerate and related copolymers that may or may not be biologically derived; polyphosphazenes; poly(amino acids) such as poly (L-lysine), poly (glutamic acid) and related copolymers.
Examples of biologically derived bioabsorbable polymers that are useful in forming the fiber 100 of the present invention include: polypeptides such as collagen, elastin, albumin and gelatin; glycosaminoglycans such as hyaluronic acid, chondroitin sulfate, dermatan sulfate, keratan sulfate, heparan sulfate and heparin; chitosan and chitin; agarose; wheat gluten; polysaccharides such as starch, cellulose, pectin, dextran and dextran sulfate; and modified polysaccharides such as carboxymethylcellulose and cellulose acetate. Examples of other dissolvable or resorbable polymers include polyethylene glycol and poly(ethylene glycol-propylene glycol) copolymers that are known as pluronics and reverse pluronics.
Examples of non-biodegradable polymers that are useful in forming the fiber 100 of the present invention include: nylon4, 6; nylon 6; nylon 6,6; nylon 12; polyacrylic acid; polyacrylonitrile; poly(benzimidazole) (PBI); poly(etherimide) (PEI); poly(ethylenimine); poly(ethylene terephthalate); polystyrene; polysulfone; polyurethane; polyurethane urea; polyvinyl alcohol; poly(N-vinylcarbazole); polyvinyl chloride; poly (vinyl pyrrolidone); poly(vinylidene fluoride); poly(tetrafluoroethylene) (PTFE); polysiloxanes; and poly (methyl methacrylate).
In one embodiment as shown schematically in
The amount of drug within the fibers of the present invention is preferably at least about 20 percent by weight. Using the methods of the present invention, the inventors have surprisingly found that high drug loading rates of 20 weight percent and higher (such as 25, 30, 35, 40, 45, 50 weight percent, and higher) are achievable. To achieve these high drug loading rates, drugs are used that are substantially insoluble in the polymer(s) of the fiber 100 (including any solvents used during the manufacturing process), or the amount of drug that is used is higher than the solubility limit of the drug in the polymer (or solvent). As such, and in contrast with known drug-loaded fiber technologies, the drug will not be dissolved within the polymer and associated solvents, but will exist in particulate form.
The fibers of the present invention are preferably manufactured using electrospinning techniques. Electrospinning is a process in which a continuous stream of polymer solution is ejected from a cylindrical tube or needle known as a “spinneret” towards a collection substrate by the application of both pressure and an electric field. During this process, the charge accumulation and evaporation of the solvent from the solution yields a single, long polymer fiber typically characterized by diameters from the nanometer to micron scale.
In a preferred embodiment, fibers of the present invention having inner and outer radial portions are manufactured using a co-axial spinneret system as schematically shown in
As the inner and outer solution feeds move through the spinneret 220, they are charged by the application of an electric potential to the outer needle 222. The charge transfers through the outer needle 222 into the outer solution feed, and preferably into the inner solution feed. One or more grounded conductive substrates 230 are placed at a predetermined distance from the end 225 of the spinneret 220, preferably on the order of tens of centimeters, as shown in
Although the electrospinning process is described with specific reference to a co-axial needle arrangement to produce a fiber 100 having inner and outer radial portions 120, 130, it should be appreciated that the present invention includes the formation of homogeneous fibers as described with reference to
The drugs used in the fibers of the present invention are any suitable drugs that are selected for treatment of the medical condition for which they are delivered, provided that they are either substantially insoluble in the polymers and solvents used in the fiber 100, or the amount of the drug exceeds the solubility limit of the drug in these materials. General categories of drugs that are useful in the present invention include, but are not limited to: opioids; ACE inhibitors; adenohypophoseal hormones; adrenergic neuron blocking agents; adrenocortical steroids; inhibitors of the biosynthesis of adrenocortical steroids; alpha-adrenergic agonists; alpha-adrenergic antagonists; selective alpha-two-adrenergic agonists; androgens; anti-addictive agents; antiandrogens; antiinfectives, such as antibiotics, antimicrobals, and antiviral agents; analgesics and analgesic combinations; anorexics; antihelminthics; antiarthritics; antiasthmatic agents; anticonvulsants; antidepressants; antidiabetic agents; antidiarrheals; antiemetic and prokinetic agents; antiepileptic agents; antiestrogens; antifungal agents; antihistamines; antiinflammatory agents; antimigraine preparations; antimuscarinic agents; antinauseants; antineoplastics; antiparasitic agents; antiparkinsonism drugs; antiplatelet agents; antiprogestins; antipruritics; antipsychotics; antipyretics; antispasmodics; anticholinergics; antithyroid agents; antitussives; azaspirodecanediones; sympathomimetics; xanthine derivatives; cardiovascular preparations, including potassium and calcium channel blockers, alpha blockers, beta blockers, and antiarrhythmics; antihypertensives; diuretics and antidiuretics; vasodilators, including general coronary, peripheral, and cerebral; central nervous system stimulants; vasoconstrictors; hormones, such as estradiol and other steroids, including corticosteroids; hypnotics; immunosuppressives; muscle relaxants; parasympatholytics; psychostimulants; sedatives; tranquilizers; nicotine and acid addition salts thereof; benzodiazepines; barbiturates; benzothiadiazides; beta-adrenergic agonists; beta-adrenergic antagonists; selective beta-one-adrenergic antagonists; selective beta-two-adrenergic antagonists; bile salts; agents affecting volume and composition of body fluids; butyrophenones; agents affecting calcification; catecholamines; cholinergic agonists; cholinesterase reactivators; dermatological agents; diphenylbutylpiperidines; ergot alkaloids; ganglionic blocking agents; hydantoins; agents for control of gastric acidity and treatment of peptic ulcers; hematopoictic agents; histamines; 5-hydroxytryptamine antagonists; drugs for the treatment of hyperlipiproteinemia; laxatives; methylxanthines; monoamine oxidase inhibitors; neuromuscular blocking agents; organic nitrates; pancreatic enzymes; phenothiazines; prostaglandins; retinoids; agents for spasticity and acute muscle spasms; succinimides; thioxanthines; thrombolytic agents; thyroid agents; inhibitors of tubular transport of organic compounds; drugs affecting uterine motility; anti-vasculogenesis and angiogenesis; vitamins; and the like; or a combination thereof.
Some embodiments of the invention comprise an active component that may include, but is not limited to: a) a corticosteroid, e.g., cortisone, hydrocortisone, prednisolone, beclomethasone propionate, dexamethasone, betamethasone, flumethasone, triamcinolone, triamcinolone acetonide, fluocinolone, fluocinolone acetonide, fluocinolone acetate, clobetasol propionate, or the like, or a combination thereof; b) an analgesic anti-inflammatory agent, e.g., acetaminophen, mefenamic acid, flufenamic acid, indomethacin, diclofenac, diclofenac sodium, alclofenac, ibufenac, oxyphenbutazone, phenylbutazone, ibuprofen, flurbiprofen, ketoprofen, salicylic acid, methylsalicylate, acetylsalicylic acid, 1-menthol, camphor, slindac, tolmetin sodium, naproxen, fenbufen, or the like, or a combination thereof; c) a hypnotic sedative, e.g., phenobarbital, amobarbital, cyclobarbital, lorazepam, haloperidol, or the like, or a combination thereof; d) a tranquilizer, e.g., fulphenazine, thioridazine, diazepam, flurazepam, chlorpromazine, or the like, or a combination thereof; e) an antihypertensive, e.g., clonidine, clonidine hydrochloride, bopinidol, timolol, pindolol, propranolol, propranolol hydrochloride, bupranolol, indenolol, bucumolol, nifedipine, bunitrolol, or the like, or a combination thereof; f) a hypotensive diuretic, e.g., bendroflumethiazide, polythiazide, methylchlorthiazide, trichlormethiazide, cyclopenthiazide, benzyl hydrochlorothiazide, hydrochlorothiazide, bumetanide, or the like, or a combination thereof; g) an antibiotic, e.g., penicillin, tetracycline, oxytetracycline, metacycline, doxycycline, minocycline, fradiomycin sulfate, erythromycin, chloramphenicol, or the like, or a combination thereof; h) an anesthetic, e.g., lydocaine, benzocaine, ethylaminobenzoate, or the like, or a combination thereof; i) another analgesic, e.g., acetylsalicylic acid, choline magnesium tri salicylate, acetaminophen, ibuprofen, fenoprofen, diflusinal, naproxen and the like; j) an antipruritic agent, e.g., bisabolol, oil of chamomile, chamazulene, allantoin, D-panthenol, glycyrrhetenic acid, a corticosteroid, an antihistamines and the like; k) an antimicrobial agent, e.g., methyl hydroxybenzoate, propyl hydroxybenzoate, chlorocresol, benzalkonium chlorides, nitrofurazone, nystatin, sulfacetamidc, clotriamazole, or the like, or a combination thereof; 1) an antifungal agent, e.g., pentamycin, amphotericin B, pyrrol nitrin, clotrimazole, or the like, or a combination thereof; m) a vitamin, e.g., vitamin A, ergocalciferol, cholecalciferol, octotriaminc, riboflavin butyric acid ester, or the like, or a combination thereof; n) an antiepileptic, e.g., nitrazepam, meprobamate, clonazepam, or the like, or a combination thereof; o) an antihistamine, e.g., diphenhydramine hydrochloride, chlorpheniramine, diphenylimidazole, or the like, or a combination thereof; p) an antitussive, e.g., dextromethorphan, terbutaline, ephedrine, ephedrine hydrochloride, or the like, or a combination thereof; q) a sex hormone, e.g., progesterone, estradiol, estriol, estrone, or the like, or a combination thereof r) an antidepressant, e.g., doxepin; s) a vasodilator, e.g., nitroglycerin, isosorbide nitrate, nitroglycol, pentaerythritol tetranitrate, dipyridamole, or the like, or a combination thereof t) local anesthetics, e.g., procaine, benzocaine, chloroprocaine, cocaine, cyclomethycaine, dimethocaine/larocaine, propoxycaine, procaine/novocaine, proparacaine, tetracainc/amethocaine, lidocaine, articaine, bupivacaine, carticaine, cinchocaine/dibucaine, etidocaine, levobupivacaine, lidocaine/lignocaine, mepivacaine, piperocaine, prilocalne, ropivacaine, trimecaine, or the like; u) another drug, e.g., 5-fluorouracil, dihydroergotamine, desmopressin, digoxin, methoclopramide, domperidone, scopolamine, scopolamine hydrochloride, or the like, or a combination thereof or the like; or a combination thereof.
Any opioid can be used in the embodiments of the present invention. Useful opioids include, but are not limited to, alfentanil, allylprodine, alphaprodine, anileridine, benzylmorphine, bezitramide, buprenorphine, butorphanol, clonitazene, codeine, desomorphine, dextromoramide, dezocine, diampromide, diamorphone, dihydrocodeine, dihydromorphine, dihydromorphone, dihydroisomorphinc, dimenoxadol, dimepheptanol, dimethylthiambutene, dioxaphetyl butyrate, dipipanone, eptazocine, ethoheptazine, ethylmethylthiambutene, ethylmorphine, etonitazene, etorphine, dihydroetorphine, fentanyl, heroin, hydrocodone, hydromorphone, hydromorphodone, hydroxypethidine, isomethadone, ketobcmidone, levorphanol, levophenacylmorphan, lofentanil, meperidine, meptazinol, metazocine, methadone, metopon, morphine, myrophine, narceine, nicomorphine, norlevorphanol, normethadone, nalorphine, nalbuphene, normorphine, norpipanone, opium, oxycodone, oxymorphone, pantopon, papavereturn, paregoric, pentazocine, phenadoxone, phendimetrazine, phendimetrazone, phenomorphan, phenazocine, phenoperidine, piminodine, piritramide, propheptazine, promedol, properidine, propoxyphene, propylhexedrine, sufentanil, tilidine, tramadol, pharmaceutically acceptable salts thereof and mixtures of any two or more thereof.
The fibers of the present invention may be used as individual implants that may be delivered within an injectable solution or as an implant without any associated solution. In other embodiments, the fibers are formed into other configurations, such as yarns, ropes, tubes, and patches. Such configurations are useful for a variety of medical applications and are used to yield desired drug delivery characteristics, deliverability, and mobility after delivery into a patient. For example, the fibers of the present invention are useful for injection into fluid-filled spaces within the body, such as joints, eye chambers, intrathecal spaces, and pericardial spaces. The fibers may also be injected or implanted into tissue, such as, for example, intramuscularly or subcutaneously, or placed into bodily lumens such as blood vessels. The fibers may also be formed into configurations that provide tissue anchoring characteristics. Examples of such configurations include ends that expand into T-Bar anchors, dart tipped or curved hooks, and the like. The fibers and implants of the present invention, and methods of making and using them, are further described with reference to the following non-limiting examples.
Homogeneous fibers made from poly ε-caprolactone (PCL) and containing 10 wt % dexamethasone were manufactured in accordance with the present invention. A solution containing 15 wt % PCL in a chloroform and acetone solvent was placed in a syringe capped with an 18 gauge needle, and connected to a syringe pump set to deliver a flow rate of about 4 mL/h. A grounded mandrel coated with polytetrafluroroethylene was placed about 17 cm from the needle tip. An electric current was applied to the needle, and a fiber was electrospun according to the electrospinning technique as described herein. The fiber was characterized by a substantially homogeneous composition and morphology, and a diameter of about 10 microns, throughout which the dexamethasone was dispersed in particulate form.
Fibers having inner and outer radial portions, or a so-called “core-sheath” structure,” were manufactured in accordance with the present invention.
A first set of core-sheath fibers were manufactured to have an outer radial portion comprising PCL and an inner radial portion comprising PCL and dexamethasone. These fibers were made by formulating an outer portion solution comprising 20 wt % PCL in chloroform/ethanol, and an inner portion solution comprising 20 wt % PCL in chloroform/acetone with 30 wt % (with respect to PCL) dexamethasone. A co-axial needle arrangement comprising a stainless steel outer tube having an inner diameter of about 2.3 mm, and a stainless steel inner tube having an outer diameter of about 0.9 mm and an inner diameter of about 0.6 mm, was used to deliver the outer and inner portion solutions, respectively, into an electrospinning process. The outer portion solution was delivered at a rate of about 23 mL/h, and the inner portion solution was delivered at a rate of about 12 mL/h. A grounded mandrel coated with polytetrafluroroethylene was placed about 20 cm from the needle tip. An electric current was applied to the needle, and a fiber was electrospun according to the electrospinning technique as described herein.
A second set of core-sheath fibers were manufactured to have an outer radial portion comprising poly lactic-co-glycolic acid (PLGA), and an inner radial portion comprising PCL and dexamethasone. These fibers were made by formulating an outer portion solution comprising 6 wt % PLGA in hexafluoroisopropanol, and an inner portion solution comprising 15 wt % PCL in chloroform/acetone with 30 wt % (with respect to PCL) dexamethasone. A co-axial needle arrangement comprising a stainless steel outer tube having an inner diameter of about 2.3 mm, and a stainless steel inner tube having an outer diameter of about 0.9 mm and an inner diameter of about 0.6 mm, was used to deliver the outer and inner portion solutions, respectively, into an electrospinning process. The outer portion solution was delivered at a rate of about 8 mL/h, and the inner portion solution was delivered at a rate of about 3 mL/h. An electric current was applied to the needle, and a fiber was electrospun according to the electrospinning technique as described herein.
Both sets of core-sheath fibers were found to have a structure characterized by inner and outer radial portions. As shown in the scanning electron micrographs in
Fibers manufactured in accordance with Examples 1 and 2 were weighed and subsequently placed into a solution of phosphate buffered saline (PBS) and cyclodextrin. The rate of dexamethasone release from the fibers was measured using UV absorbance techniques. As expected, the homogeneous fiber structures manufactured in accordance with Example 1 resulted in a more pronounced “burst” drug release profile as compared to the core-sheath fiber structures manufactured in accordance with Example 2. As a result, the dexamethasone was found to be substantially released from the homogeneous fibers within about five hours. In comparison, the fibers in the first set of Example 2 yielded a dexamethasone release through about 120 hours after placement within the PBS solution, and the fibers in the second set of Example 2 yielded a dexamethasone release through about 170 hours after placement within the PBS solution.
Core-sheath fibers were manufactured having an outer radial portion comprising PLGA and an inner radial portion comprising PCL and dexamethasone. The fibers were made using an outer portion solution comprising 4 wt % PLGA in hexafluoroisopropanol, and an inner portion solution comprising 20 wt % PCL in chloroform/acetone with 20 wt % (with respect to the PCL) dexamethasone. The amount of dexamethasone within all fibers was about 13 wt %. A co-axial needle arrangement comprising a stainless steel outer tube having an inner diameter of about 2.3 mm, and a stainless steel inner tube having an outer diameter of about 0.9 mm and an inner diameter of about 0.6 mm, was used to deliver the outer and inner portion solutions, respectively, into an electrospinning process. A grounded mandrel coated with polytetrafluroroethylene was placed about 20 cm from the needle tip. An electric current was applied to the needle, and a fiber was electrospun according to the electrospinning technique as described herein. Three fiber structures were electrospun according to this Example, with only the feed rate of the inner and outer portion solutions being varied during the electrospinning process as follows:
The fibers were weighed and subsequently placed into a solution of phosphate buffered saline (PBS) and cyclodextrin. The rate of dexamethasone release from the fibers was measured using UV absorbance techniques. The inventors surprisingly found that although both the dexamethasone loading and the relative PLGA to PCL ratio was substantially identical for all fibers, the elution profiles depended upon the feed rates of the inner and outer solutions during electrospinning. For example, as shown in
Core-sheath fibers were manufactured to have an outer radial portion comprising poly lactic-co-glycolic acid (PLGA), and an inner radial portion comprising PCL and dexamethasone. These fibers were made from an outer portion solution comprising PLGA in chloroform and methanol, and an inner portion solution comprising PCL in chloroform and acetone. Three sets of fibers were manufactured using an electrospinning process analogous to the process described in Example 2—the core solution contained a high drug loading, 80 wt % with respect to PCL. By varying the outer solution conditions, three sets of fibers were produced: one set with a dexamethasone content of 30 wt %, a second set with a dexamethasone content of 50 wt %, and a third set with a dexamethasone content of 67 wt % (with respect to total fiber mass). The fibers were weighed and subsequently placed into a solution of phosphate buffered saline (PBS) and cyclodextrin. The rate of dexamethasone release from the fibers was measured using UV absorbance techniques. As shown in
In one embodiment, fibers of the present invention are formed into drug-containing yarns. Such yarns are formed by electrospinning a fiber as previously described, with the fiber being collected on grounded collectors 310 that have a predetermined gap 311 there between, as shown in
In one embodiment, multiple yarns as described in Example 6 are made and twisted into a rope. As shown in
In other embodiments, ropes according to the present invention comprise yarns with differing compositions, properties, drug release rates, and/or drugs loaded therein. For example, ropes of the present invention may be useful for applications in which two therapeutic agents work synergistically, which may be accomplished by forming one yarn comprising a first synergistic agent, forming another yarn comprising a second synergistic agent and/or an adjuvant to the first agent, and then twisting the yarns into a rope. As an example of such an application, agents such as bupivacaine and morphine may be loaded into individual yarns and subsequently formed into a rope.
The mechanical properties of the ropes of the present invention may be controlled by varying the number of yarns. For example, the inventors have measured the following mechanical properties of ropes made from PLGA yarns, where the number of yarns within the ropes varied between one, three, and six:
In one embodiment, fibers of the present invention are formed into drug-containing tubes. To make such tubes, drug-containing fibers are electrospun as previously described, but onto an elongated, grounded wire preferably having a diameter less than about 200 microns. After the solvent is evaporated following the electrospining process, the wire is extracted to yield a hollow tube 400 having a through cavity 410 and a side wall 411 that is made from one or more drug-containing fibers 100, as shown in
In some embodiments, the tubes 400 of the present invention are further processed to include a drug inside the through cavity 410. This drug may be the same or different from the drug included in the fibers 100 that make up the side wall 411 of the tubes. In such embodiments, the inherent porosity of the side wall 411 can be altered using pressure, heat, or the application of solvent(s), which will in turn alter the delivery rate of drug from the fibers 100 of the tube side wall 411 and the through cavity 410. The use of drugs both within the fibers 100 and through cavities 410 allows for tailored drug delivery profiles such as an immediate burst release followed by a sustained release.
In one embodiment, fibers of the present invention are formed into drug-containing patches 500, as shown in
In an alternate embodiment, a tube 400 made of drug-containing fibers is made from a patch 500 that is electrospun onto a grounded metal substrate. Following the electrospinning process, the patch is removed from the substrate and rolled into tubes, preferably having a diameter ranging from about 50 microns to about 1 millimeter.
In one embodiment, the fibers of the present invention are used to treat joint conditions such as osteoarthritis. Fibers may be delivered “dry” for this purpose, or may be included within a composition comprising a flowable material. If the latter, the flowable material is any suitable material that can be administered to an affected joint of a patient suffering from arthritis or other joint condition. Examples of such flowable materials are liquids such as saline, buffer, and isotonic solutions; gels such as those that include polymers such as alginates, glycosaminoglycans (GAGs), water soluble gums including agar, arabic, carob, carrageenans, cellulosics, chitin and chitosan based polymers, chondroitin sulfate, ethylene oxide containing polymers, poloxamers, ghatti, guars, hyaluronic acid, karaya, kadaya, locust bean, tragacanth, xantham, laminin, elastin, and other viscous media.
Fibers of the present invention having lengths on the order of hundreds of microns are suspended within the flowable material. The volume percent of the fibers within the flowable material is within any suitable range to provide for a desired therapeutic effect. The fibers are preferably biodegradable, and are made from suitable biocompatible materials that do not cause significant adverse effects when administered to a patient. Such materials include, but are not limited to synthetic absorbable polymers such as polyesters such as polydioxanone (PDO), polylactic acid (PLA), poly lactic-co-glycolic acid (PLGA), poly ε-caprolactonc (PCL) and copolymers thereof, poly glycolide (PGA), polyhydroxybutyrate (PUB), polyhydroxyalkanoate (PHA), poly glycerol sebacate (PGS); polycarbonates such as poly trimethylene carbonate (PTMC); polyanhydrides such as poly (sebacic anhydride), poly (bis carboxyphenoxypropane), degradable urethanes, and polyphasphazenes; natural polymers such as glycosaminoglycans, hyaluronic acid, laminin, elastin, collagen, gelatin, and albumin; and dissolvable polymers such as dextran, dextran sulfate, carboxymethyl cellulose, polyvinyl alcohol, polyethylene glycol and copolymers thereof, and pluronic polymers.
The fibers include inner and outer radial portions, as shown in
The fiber suspension within the flowable material is injected to affected joints using methods that are known in the art. In a preferred embodiment, the fiber suspension is directly injected via a needle injection into or near a joint to be treated, for example into the intra-articular space of the knee or the fat pad immediately adjacent to the knee joint capsule. As non-limiting examples, the compositions of the present invention are injectable into and around the joints of the knee, shoulder, hip, wrist, ankle, and hand, and are also injectable into the vertebral column, the mandible (jawbone), and sinus cavity. Injection can occur during or post-surgical procedures, or independently from surgical procedures. The advantages of the present invention can result in the minimization of the number of injections that are necessary to achieve a desired clinical effect.
In another embodiment of the present invention, fibers are used to treat ocular diseases. Non-limiting examples of such diseases include scleritis, keratitis, corneal ulcers, corneal neovascularization, Fuchs' dystrophy, keratoconus, iritis, uveitis, cataracts, retinopathy, macular degeneration, macular edema, and glaucoma.
In a non-limiting example, co-axial fibers of the present invention are configured with outer and inner radial portions comprising PLGA and PCL, respectively, and fluocinolone acetonide contained within the inner radial portion. One or more fibers are cut into a lengths on the order of several millimeters, and injected into the vitreous humor of a patient's eye with a small diameter needle, in a procedure similar to intravitreal injection, to treat conditions such as diabetic macular edema, age-related macular degeneration, and/or posterior uveitis. Fluocinolone acetonide containing fibers may additionally be injected into the aqueous humor to treat anterior uveitis or scleritis.
In another embodiment of the present invention, fibers are used to deliver drugs to the spine to treat pain (such as chronic pain, cancer pain, or other pain such as lower back pain) or diseases of the central nervous system (CNS) such as spasticity, Parkinson's, Alzheimer's, etc. For example, a rope of the present invention may be loaded with an appropriate therapeutic agent such as sufentanil, fentanyl, gentanyle, hydromorphone, morphine, bupivacaine, buprenorphine, or ziconitide, as described herein, and injected to a site near the pain receptors, such as the epidural or intrathecal space, for sustained pain relief with minimal systemic side effects.
Ropes were manufactured and implanted into cadaveric dogs to demonstrate the applicability and deliverability of embodiments of the present invention. First, yarns were formed in accordance with Example 6. Radiopaque marker bands having an inner diameter larger than the yarn outer diameters were placed over one of the yarns. The yarns were adhered to fixtures and twisted into ropes, as described in Example 7. The ropes containing marker bands were implanted into a cadaveric dog using standard catheter-based delivery systems and methods. As shown in
Fibers, either alone or in the form of tubes, yarns, or ropes of the present invention, may be injected into a patient for the systemic delivery of therapeutic agents. Such injections may be made as intramuscular or subcutaneous injections by a needle, either as dry fibers or as fibers in a flowable suspension. Such systemic delivery allows for sustained drug release for prolonged time periods up to several months. As one non-limiting example, risperidone is included within the inner portion of core-sheath fibers of the present invention, and administered by intramuscular injection for the treatment of schizophrenia.
The present invention includes fibers, methods of making such fibers, implants made from such fibers, and methods of treating patients using such fibers. The inventors have found it possible to manufacture small fibers with surprisingly high drug loading rates, and drug release profiles that may be tailored to the specific requirements of numerous medical applications. While aspects of the invention have been described with reference to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention.
This application claims the benefit of U.S. Provisional Application No. 61/146,060, entitled “Compositions and Methods for Treating Joint Conditions” by Palasis, et al., the disclosure of which is incorporated herein by reference.
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| 61146060 | Jan 2009 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12620334 | Nov 2009 | US |
| Child | 13571545 | US |
