Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/02—Halogenated hydrocarbons
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
  • A61K31/41—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having five-membered rings with two or more ring hetero atoms, at least one of which being nitrogen, e.g. tetrazole
  • A61K31/425—Thiazoles
  • A61K31/428—Thiazoles condensed with carbocyclic rings
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K38/00—Medicinal preparations containing peptides
  • A61K38/16—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
  • A61K38/17—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
  • A61K38/18—Growth factors; Growth regulators
  • A61K38/185—Nerve growth factor [NGF]; Brain derived neurotrophic factor [BDNF]; Ciliary neurotrophic factor [CNTF]; Glial derived neurotrophic factor [GDNF]; Neurotrophins, e.g. NT-3

Definitions

• This invention relates to a method of protecting living tissue from damage caused by hypoxic or ischemic conditions such as those resulting from acute vascular occlusions. More particularly, the present invention relates to the use of synthetic oxygen carriers, including perfluorocarbon-based emulsions, to carry gases to hypoxic or ischemic living tissue, and thereby ameliorate damage.
• Ischemia is a deficiency of blood supply to the tissue due to functional constriction or actual obstruction of a blood vessel.
• myocardial ischemia is a deficiency of blood supply to heart muscle due to obstruction or constriction of the coronary arteries. If ischemia continues for more than a few seconds, tissue damage can result from a complex series of biochemical events associated with the ischemia-induced tissue hypoxia.
• emboli Hypoxic or ischemic conditions produced by emboli can result in tissue damage that is particularly debilitating if the damaged tissue is heart tissue or neural tissue of the central nervous system (CNS).
• CNS central nervous system
• the two most serious consequences of emboli are heart attack (acute myocardial infarct or AMI), resulting from cardiac muscle ischemia, and stroke, resulting from brain tissue ischemia.
• AMI acute myocardial infarct
• Ischemia which does not lead to AMI or stroke can, nonetheless, produce serious symptoms in the individual such as chest pains (angina pectoris), partial paralysis, confusion, disorientation and/or memory loss.
• Atherosclerosis Individuals with vascular disease, particularly atherosclerosis, are particularly at risk for developing emboli that can result in AMI or stroke.
• Ischemic heart disease affects millions of people worldwide, often leading to sudden death by AMI.
• Ischemia can result when solid emboli produced from portions of plaque that dislodge and move through the circulatory system lodge in a capillary or attach to another plaque deposit in a blood vessel, thus fully or partially occluding the vessel or capillary.
• Atheromatous plaque particles can also be generated during vascular and cardiac surgery procedures (e.g. cannulation, clamping) that manipulate or disturb any atherosclerotic blood vessels (e.g., carotids, coronaries, aorta, femoral or popliteal vessels).
• occlusions generally involves bypassing the blocked vessel, or removing and/or dissolving emboli using mechanical means and/or thrombolytic enzymes.
• treatment of intracoronary thrombotic events such as myocardial infarcts usually involves one or a combination of treatments. These include coronary bypass surgery, percutaneous coronary angioplasty (PTCA) and systemic administration of thrombolytic agents, such as tissue plasminogen activator (tPA) or streptokinase.
• PTCA percutaneous coronary angioplasty
• tPA tissue plasminogen activator
• streptokinase tissue plasminogen activator
• Synthetic oxygen carriers often referred to as "blood substitutes” have been shown to augment delivery of oxygen through the circulatory system when red blood cells (i.e., hemoglobin) are partially depleted, such as during surgery, or resulting from injury with bleeding or hemorrhagic disorders.
• red blood cells i.e., hemoglobin
• synthetic oxygen carriers can be used to treat conditions where the red blood cells are partially non-functional, as may occur in patients with certain genetic disorders, or patients undergoing hypothermic procedures such as cardiopulmonary bypass or circulatory arrest.
• Such oxygen carriers or blood substitutes are disclosed in U.S. Patent No. 5,344,393 and U.S. Patent No. 5,451,205.
• Other blood substitutes are known as disclosed in U.S. Patent No. 5,114,932, U.S. Patent No.
• Perfluorocarbon emulsions such as FLUOSOLTM (Green Cross Corporation, Japan) and OXYGENTTM (perflubron-based emulsion) (Alliance Pharmaceutical Corp., San Diego, USA), are known to be efficient synthetic oxygen carriers that are generally well tolerated in vivo by humans. Synthetic oxygen carriers comprising hemoglobin, which can be derived from human, animal, or recombinant sources, is also known in the art.
• one system includes perfluorocarbon in a nutrient emulsion or "synthetic cerebrospinal fluid" to treat CNS hypoxic-ischemic conditions (U.S. Patent No. 4,445,514).
• the oxygenated emulsion is administered directly into the cerebrospinal fluid and artificially circulated through extracorporeal means.
• Perfluorocarbon emulsions have also been used in an experimental animal model of partial brain stem ischemia and shown to enhance recovery of brain stem function following reperfusion (Guo et al., Neurosurgery 36(2): 350-357, 1995).
• Perfluorocarbons and blood substitutes have also been used for drug delivery.
• infusions of a neuroprotectant and a perfluorochemical emulsion have been disclosed as a treatment for conditions involving cerebral hypoxia (PCT International Application No. WO 97/15306).
• a method of preventing or treating tissue hypoxia or ischemia including the step of administering systemically a synthetic oxygen carrier to an individual having or suspected of having blood vessel obstruction.
• the invention may be used to provide neuroprotection or retard neurodegeneration in a patient in need thereof through a reduction in the adverse effects of cerebral ischemic hypoxia.
• Other preferred embodiments comprise the use of synthetic oxygen carriers in chronic or long-term therapeutic regimens for the reduction or treatment of ischemic or hypoxic associated effects.
• Another embodiment comprises the use of perf luorochemical-based formulations to reduce the inflammatory process triggered locally by the ischemic insult and related tissue hypoxia.
• the oxygen carrier is administered by intravenous injection or infusion.
• the synthetic oxygen carrier is a perfluorocarbon emulsion, crystalloid blood substitute, a colloid blood substitute, or combinations thereof.
• the present invention comprises the use of a synthetic oxygen carrier in the manufacture of an oxygen carrying medicament for the treatment of tissue hypoxia due to ischemia or acute anemia, wherein said oxygen carrying medicament is administered systemically to an individual having or suspected of having blood vessel obstruction caused by solid emboli, or temporary clamping of vessels during surgery.
• Particularly preferred embodiments of the invention comprise the use of synthetic oxygen carriers which are fluorocarbon-in-water emulsions comprising a discontinuous fluorocarbon phase and a continuous aqueous phase.
• the fluorocarbon-in-water emulsion includes a perfluorocarbon phase and an aqueous phase.
• the fluorocarbon emulsion also includes an emulsifying agent or dispersant, osmotic agent, buffer, electrolyte or combinations thereof.
• fluorocarbon is used in a broad sense and comprises any highly fluorinated compound such as a linear, branched, cyclic, saturated or unsaturated fluorinated hydrocarbon, optionally containing at least one heteroatom and/or bromine or chlorine atom, wherein at least 30% of the hydrogen atoms of said hydrocarbon compound have been replaced by fluorine atoms.
• Particularly preferred embodiments comprise perfluorocarbons.
• fluorocarbon emulsions including bis(F-alkyl) ethanes, cyclic fluorocarbons, perfluorinated amines, brominated perfluorocarbons, chlorinated fluorocarbons, perfluoroalkylated ethers, perfluoroalkylated polyethers or mixtures thereof that are dispersed in an aqueous phase.
• Fluorocarbons compatible with the present invention are generally selected for beneficial physical characteristics such as low toxicity, low surface tension, high spreading coefficient and the ability to transport gases. Hemoglobin compositions contemplated for use in the present invention are well known.
• compositions may be comprised of stroma-free, intramolecularly cross-linked, conjugated, polymerized, or recombinant hemoglobin or combinations thereof.
• Such compositions are disclosed, for example, in the following U.S. Patents, which are hereby incorporated by reference: 4,911,929; 4,861,867; 4,857,636; 4,777,244; 4,698,387; 4,600,531; 4,526,715; 4,473,494; and 4,301,144.
• the present invention provides methods for delivering a bioactive agent to a patient using the disclosed oxygen carriers.
• bioactive agent is defined to mean any pharmaceutical compound or composition, including diagnostic and therapeutic agents or drugs as well as physiologically acceptable gases such as oxygen or nitric oxide, which may be administered to an animal to treat a disorder or disease.
• bioactive agents or drugs compatible with the present invention include, but are not limited to, antibiotics, antivirals, a ⁇ ti-inflammatories, antineoplastics, intravenous anesthetics, volatile anesthetics, enzymes, cardiovascular agents, polynucleotides, genetic material, viral vectors, immu ⁇ oactive agents, imaging agents, immunosuppressive agents, peptides, proteins and combinations thereof.
• the incorporated drug is a drug that promotes dissolving emboli, or a neuroprotective compound, in a selected embodiment, the neuroprotective compound is a neuropeptide, a nerve growth factor or 2-aminobenzothiazole derivative.
• the invention provides for the use of a synthetic oxygen carrier in the manufacture of an oxygen carrying medicament for providing neuroprotection or retarding neurodegeneratio ⁇ through a reduction in effects associated with cerebral ischemia or hypoxia wherein said oxygen carrying medicament is administered systemically to a patient in need thereof.
• the present invention provides for the delivery of bioactive agents using emulsified medicaments capable of carrying oxygen.
• embodiments of the present invention comprise the use of a fluorocarbon in the manufacture of an oxygen carrying emulsified medicament for the delivery of a bioactive agent wherein said emulsified medicament comprises an aqueous continuous phase, a nonaqueous dispersed phase, an emulsifying agent and a bioactive agent and wherein said emulsified medicament is administered to a patient in need thereof.
• the oxygen carrier may be administered either prophylactically to prevent the ischemia-induced tissue hypoxia, or as a treatment of therapy for symptoms associated with ischemia, whereas in other embodiments the administration step is performed after the ischemic event to correct symptoms associated with ischemia or hypoxia.
• the administration step may be performed prior to a surgical procedure to protect against emboli which will cause ischemia, or during the surgical procedure, or within 24 hours or several days after a surgical procedure to treat tissues at risk of hypoxia to emboli or other ischemic events.
• embodiments of the invention comprise the chronic or long term administration of oxygen carriers to reduce the deleterious effects of ischemic or hypoxia.
• Such therapeutic regimens may involve the low dose administration of the selected oxygen carrier for a period of weeks or even months.
• the actual administration of the oxygen carrier may preferably comprise discrete introductions on a periodic basis (i.e. once a day or once a week) or a constant slow infusion of the oxygen carrier using techniques well known in the art.
• the oxygen carrier may further comprise an additional bioactive agent. It will be appreciated that such regimens may be particularly useful for ameliorating symptoms associated with chronic neurodegenerative conditions such as Alzheimer's disease, Parkinson's disease or epilepsy.
• the long term administration of oxygen carriers may be used to treat non-neuronal conditions.
• preferred embodiments of the invention provide for use of a synthetic oxygen carrier in the manufacture of an oxygen carrying medicament for the treatment of a chronic or long term hypoxic or ischemic condition in a patient in need thereof wherein said oxygen carrying medicament is administered periodically, intermittently or continuously to said patient for a treatment period greater than one week.
• the method includes administering a volume of an intravenous fluid including the synthetic oxygen carrier, wherein the synthetic oxygen carrier is at least about equal to 0.1 % of the individual's normal blood volume. In other embodiments, the volume of an intravenous fluid including the synthetic oxygen carrier is equal to about 1 % to about 20%, or 30% of the individual's normal blood volume.
• a composition including a synthetic oxygen carrier in a physiologically acceptable carrier, wherein the synthetic oxygen carrier includes submicron-sized particles capable of passing through emboli-obstructed blood vessels.
• the synthetic oxygen carrier is a fluorocarbon-in-water emulsion of a discontinuous fluorocarbon phase and a continuous aqueous phase, wherein the fluorocarbon phase includes submicron sized particles.
• the fluorocarbon-in-water emulsion also includes an emulsifying agent, osmotic agent, buffer, electrolyte, therapeutic drug or combinations thereof.
• Particularly preferred compositions of the present invention comprise fluorochemical emulsions that further incorporate at least one neuroprotective bioactive agent. Additional embodiments include oxygen carriers derived from human, animal, plant, or recombinant hemoglobin.
• the present invention further provides compositions comprising a synthetic oxygen carrier in a physiologically acceptable carrier, wherein the synthetic oxygen carrier comprises submicron sized particles capable of passing through emboli-obstructed blood vessels.
• the present invention provides methods of treating a mammal suffering from full or partial occlusion of a blood vessel, and therefore having ischemia and hypoxia in a tissue that depends on the blocked vessel for blood and oxygen, by administering intravenously a synthetic oxygen carrier.
• the occlusion is the result of solid emboli comprising a naturally occurring structure such as a blood clot or lipid.
• the present invention comprises a method for imparting neuroprotection to a mammal through the administration of a synthetic oxygen carrier that may ameliorate effects associated with cerebral ischemia or hypoxia.
• Still other embodiments of the present invention comprise the administration of bioactive agents using a synthetic oxygen carrier.
• the bioactive agent is neuroprotective in nature and the oxygen carrier is a fluorochemical emulsion.
• Still other embodiments of the invention comprise the chronic or long-term administration of a synthetic oxygen carrier to ameliorate effects associated with ischemic or hypoxic conditions.
• oxygen carrier is meant a compound capable of transporting oxygen and other gases, although those other gases may not be explicitly stated when referring to the carrier.
• synthetic is meant a compound that is chemically synthesized (e.g., fluorocarbons) or isolated and purified from a naturally occurring or biologically based source (e.g. hemoglobin purified from human, animal, plant, bacterial or other sources).
• solid emboli is meant a constriction or occlusion of a blood vessel by a naturally occurring structure such as a blood clot, plaque particle, lipid droplets, cellular debris or dissection of the intimal lining of a blood vessel such as resulting from a mechanical procedure, such as occurs during balloon inflation in angioplasty procedures.
• the synthetic oxygen carrier used in the method of the present invention is preferably of sufficiently small size to continue to flow through the occluded vessel, unlike the whole red blood cells that are blocked, and therefore can promote gaseous exchange (e.g., oxygen delivery and removal of C0 2 ) in the ischemic tissue during the time before the occlusion is removed.
• the oxygen carrier may be delivered in a pharmaceutically acceptable carrier and preferably uses preparations which have a limited intravascular half-life (blood substitutes) that do not cause adverse hemodynamic effects.
• Preferred oxygen carriers include fluorocarbon emulsions, more preferably perfluorocarbon emulsions, acellular Hb solutions and known crystalloid compositions and colloid compositions that are typically used as blood substitutes (i.e., compositions used to maintain a patient's normal blood volume and to increase cardiac output).
• Such oxygen carriers and blood substitutes are known in the art.
• Suitable perfluorocarbons are biologically and biochemically inert compounds made of carbon and fluorine that dissolve oxygen and carbon dioxide and have a half-life of several hours in the body.
• the perfluorocarbon oxygen carrier is administered as an emulsion having sufficiently small particles of perfluorocarbon suspended in an aqueous phase that the particles can pass by emboli in blood vessels, particularly in capillaries.
• the submicron size of perfluorocarbon emulsions permits the oxygen carrier to perfuse the microcirculation of capillaries, including situations when vasoconstriction or partial occlusion prevents red blood cells from passing through the vessels, thus allowing the perfluorocarbon particles to perfuse the hypoxic tissue and provide some additional delivery of oxygen and removal of carbon dioxide.
• the small perfluorocarbon particles are still capable of perfusing through any partially patent collateral vessels to minimize the size of the hypoxic zone (i.e., the penumbra or region around the area of severe infarct, where the tissue is still viable but at risk of further injury if oxygen flow is not restored quickly).
• Other synthetic oxygen carriers that do not rely on submicron particle size of an emulsion, but that are also capable of perfusing partially occluded or collateral vessels are also contemplated by the present invention.
• the synthetic oxygen carrier can also maintain or enhance the circulation of other dissolved gases (e.g., nitric oxide), and remove unwanted gases (e.g., C0 2 or N 2 ).
• the oxygen carrier used is capable of removing or neutralizing free radicals generated at sites where ischemia or localized tissue hypoxia may be occurring, thereby ameliorating any inflammatory process and reperfusion injury that may otherwise occur when the blood supply is restored to the tissue.
• the synthetic oxygen carrier can also serve as a means of delivering therapeutic drugs as an adjunct to the therapeutic oxygen delivery.
• therapeutic drugs for example, streptokinase or tPA can be delivered to the emboli, neuroprotectants can be delivered to neural tissue affected by the obstruction and anti-inflammatory agents may be delivered to an ischemic area to prevent further damage.
• a perfluorocarbon emulsion is used to deliver physiologically acceptable amounts of the therapeutic drugs using well-known clinical protocols.
• Neuroprotectants that include 2- aminobenzothiazole derivatives, such as those disclosed in PCT International Application No. WO 97/15306, nerve growth factor (NGF), known physiologically active neuropeptides, or other anti-hypoxic drugs such as those disclosed in U.S. Patent No.
• NMDA neuropeptides
• AMPA adenosine
• glycine or gluta ate acetyl-l-carnitine
• free radical scavengers free radical scavengers
• sulfonylureas calpastatin
• inhibitors Cholinesterase, nitric oxide synthase, protein kinase C
• NSAIDs neurotrophic factors, vasodilators, antioxidants and combinations thereof.
• the method of the present invention is generally contemplated as a treatment for hypoxic or ischemic tissue that has resulted from occlusions of vessels that have already occurred (i.e., when a patient presents with symptoms of occlusion), it can also be used proph ⁇ lactically when the potential for occlusion resulting from solid emboli in the circulation is sufficiently high.
• the method may be used during vascular, neural surgery and cardiac surgery in which solid emboli may be produced from atheromatous plaque particles that dislodge and move through the circulatory system, lodging in other atherosclerotic blood vessels.
• the method is also contemplated to use as a post-surgical procedure for vascular, neurosurgery and cardiac surgery in atherosclerotic patients, even if occlusion resulting from dislodged plaque particles has not been clinically detected. Further, the disclosed methods may also be used to treat chronic or long term conditions through the administration of an oxygen carrier over a sustained period of weeks or months.
• perfluorocarbons as oxygen carriers ameliorate ischemic damage due to solid emboli by providing oxygen to the tissue, either by passing around the occlusion or by increasing the gas exchange in collateral vessels to minimize the hypoxic zone, and by other anti-inflammatory properties associated with the perfluorocarbon compositions.
• Neat perfluorocarbons, particularly perflubron, have been found to possess anti-inflammatory properties by affecting the cell membranes of white blood cells, thus preventing them from sticking to injured tissue or the occlusion.
• the fluorochemical emulsions disclosed herein possess the same beneficial characteristics.
• the methods of the present invention may prevent activated neutrophils from adhering to clotted fibrinogen.
• the cycle of progressively worsening localized inflammation is attenuated or interrupted, thereby preventing further injury to the hypoxic or surrounding tissue and allowing the tissue to heal.
• fluorocarbon emulsions including but not limited to perfluorocarbon emulsions.
• emulsions are typically fluorocarbon-in-water emulsions having a discontinuous fluorocarbon phase and a continuous aqueous phase.
• the emulsions typically include emulsifying agents and osmotic agents, together with buffers and electrolytes.
• the fluorocarbon emulsion may be selected from a wide range of suitable emulsions.
• a fluorocarbon-in-water emulsion having a preferred fluorocarbon concentration of about 5% to about 125% weight per volume (w/v) is used.
• concentrations defined as "w/v” are understood to represent grams/dl, and
• % weight per volume are understood to represent grams/100 ml.
• Fluorocarbons or fluorochemicals are fluorine substituted hydrocarbons that have been used in medical applications as imaging agents and as blood substitutes.
• fluorocarbons including brominated perfluorocarbons, used as a contrast enhancement medium in radiological imaging.
• Brominated fluorocarbons and other fluorocarbons are known to be safe, biocompatible substances when appropriately used in medical applications.
• the fluorocarbon is a perfluorocarbon or substituted perfluorocarbon.
• Fluorocarbon molecules used in these emulsions may have various structures, including straight or branched chain or cyclic structures, as described in Riess, J., Artificial Organs 8(1):44-56 (1984). These molecules may also have some degree of unsaturation, and may also contain bromine or hydrogen atoms, or may be amine derivatives.
• the fluorocarbons may be present in the emulsion in any useful concentration, but usually range from about 5% to 125% w/v.
• concentrations as low as 5% w/v are contemplated, in a preferred embodiment the concentrations are at least about 25% or 30%, preferably at least about 40%, 50%, 55%, 60%, 75% or 80% w/v.
• Emulsions of about 60%, 85%, 90%, and 100% are particularly preferred, as are emulsions comprising perfluorooctyl bromide.
• Preferred fluorocarbon emulsion formulations include those disclosed in U.S. Patent Nos. 4,865,836, 4,987,154, and 4,927,623, 6,628,930 and 5,635,538, which are hereby incorporated by reference.
• Suitable fluorocarbons may be selected from brominated perfluorocarbons, such as 1-bromo- heptadecafluoro-octane (C 8 F 17 Br, sometimes known as perfluorooctylbromide, "PFOB", or “perflubron"), 1- bromopenta-decafluoroheptane (C 7 F, 5 Br), and 1-bromotridecafluorohexane (C 6 F 13 Br, sometimes known as perfluorohexylbromide or "PFHB”).
• brominated fluorocarbons are disclosed in U.S. Patent No. 3,975,512 to Long.
• fluorocarbons having nonfluorine substituents such as perfluorooctyl chloride, dichlorofluorooctane, perfluorooctyl hydride, and similar compounds having different numbers of carbon atoms (e.g., 6- 12 carbons).
• Additional fluorocarbons contemplated in accordance with this invention include perfluoroalkylated ethers or polyethers, such as (CF 3 ) 2 CFO(CF 2 CF 2 ) 2 0CF(CF 3 ) 2 , (CF 3 ) 2 CFO-(CF 2 CF 2 ) 3 OCF(CF 3 ), (CF 3 )CFO(CF 2 CF 2 )F, (CF 3 ) 2 CF0(CF 2 CF 2 ) 2 F, (C 6 F 13 ) 2 0.
• perfluoroalkylated ethers or polyethers such as (CF 3 ) 2 CFO(CF 2 CF 2 ) 2 0CF(CF 3 ) 2 , (CF 3 ) 2 CFO-(CF 2 CF 2 ) 3 OCF(CF 3 ), (CF 3 )CFO(CF 2 CF 2 )F, (CF 3 ) 2 CF0(CF 2 CF 2 ) 2 F, (C 6 F 13 ) 2 0.
• esters, thioethers, and other variously modified mixed fluorocarbon-hydrocarbon compounds are also encompassed within the broad definition of "fluorocarbon” materials suitable for use in the present invention. Mixtures of fluorocarbons are also contemplated for use in the discontinuous phase. Additional "fluorocarbons" not listed here, but having properties described herein that would lend themselves to use in vivo in accordance with the present invention, are further contemplated.
• Emulsifying agents used in the emulsions of this invention may be anionic, cationic or non-ionic surfactants or combinations thereof, as are well known to those skilled in the art, or may be mixtures of synthetic compounds such as Pluronic F-68, a condensate of ethylene oxide with propylene glycol, as described in U.S. Patent No. 4,073,879 to Long. Fluorosurfactants, such as those described by J. Riess et al. Int'l Symposium on Blood Substitutes, Montreal, (May, 1987), are also particularly suitable for use. Emulsifying agents may also be mixtures of the above described agents.
• Particularly suitable emulsifiers include natural amphipathic compounds such as phosphoiipids, particularly phosphatidylcholi ⁇ e, wherein combined hydrophilic and hydrophobic properties enable the molecule to interface with both aqueous and fluorocarbon systems, thereby forming emulsion droplets.
• phosphoiipids particularly phosphatidylcholi ⁇ e
• hydrophilic and hydrophobic properties enable the molecule to interface with both aqueous and fluorocarbon systems, thereby forming emulsion droplets.
• phosphoiipids such as the phospholipid cholines, comprising various pairings of saturated and unsaturated fatty acids in the gl ⁇ cerol structures.
• Phosphatidylchoiine is an abundant natural material (lecithin) which may be purified from egg yolk, or produced synthetically (Avanti Polar Lipids, Pelha , AL).
• Phospholipid emulsifiers particularly egg yolk phospholipid and lecithin
• Exemplary phosphoiipids useful in the disclosed stabilized preparations comprise egg phosphatidylchoiine, dilauroylphosphatidylcholine, diole ⁇ lphosphatidylcholine, dipalmito ⁇ lphosphatidylcholi ⁇ e, disteroylphosphatidylcholine, short-chain phosphatidylcholines, phosphatidylethanolamine, dioleylphosphatidylethanolamine, phosphatidylserine, phosphatidylglycerol, phosphatidylinositol, glycolipids, gangiioside GM1, sphingomyelin, phosphatidic acid, cardiolipin; lipids bearing polymer chains such as polyethylene glycol, chitin, hyaluronic acid, or polyvinylpyrrolidone; lipids bearing sulfon
• the phospholipid emulsifying agent is typically included in the range of from about 2 to 14% w/v, usually increasing the phospholipid concentration with increasing fluorocarbon concentration.
• the phospholipid comprises at least 2% w/v of the emulsion.
• the preferred amount for an emulsion comprising 75% w/v bromofiuorocarbon is 2.5 to 5% w/v of phospholipid, and for an emulsion having 100% w/v bromofluorocarbon is 3.5 to 10% w/v of phospholipid.
• compatible nonionic detergents comprise: sorbitan esters including sorbitan trioleate (Span® 85), sorbitan sesquioleate, sorbitan monooleate, sorbitan monolaurate, polyoxyethylene (20) sorbitan monolaurate, and polyoxyethylene (20) sorbitan monooleate, oleyl poiyox ⁇ ethyiene (2) ether, stearyl polyoxyethylene (2) ether, lauryl polyoxyethylene (4) ether, glyceroi esters, and sucrose esters.
• sorbitan esters including sorbitan trioleate (Span® 85), sorbitan sesquioleate, sorbitan monooleate, sorbitan monolaurate, polyoxyethylene (20) sorbitan monolaurate, and polyoxyethylene (20) sorbitan monooleate, oleyl poiyox ⁇ ethyiene (2) ether, stearyl polyoxyethylene (2) ether, lauryl polyoxyethylene (4)
• Nonionic detergents can be easily identified using McCutcheon's Emulsifiers and Detergents (McPubiishing Co., Glen Rock, New Jersey) which is incorporated herein in its entirety.
• Preferred block copolymers include diblock and triblock copolymers of polyoxyethylene and pol ⁇ ox ⁇ propyiene, including poloxa er 188 (Pluronic® F-68), poloxamer 407 (Pluronic® F-127), and poloxamer 338.
• Ionic surfactants such as sodium sulfosuccinate, and fatty acid soaps may also be utilized. It will be appreciated that these surfactants may be used alone, in combination with one another or in combination with the lipids discussed above.
• cationic surfactants or lipids may be preferable in embodiments comprising delivery of nucleic material such as RNA or DNA.
• suitable cationic lipids include: DOTMA, N-[1 -(2,3-dioleyioxy)propyl]-N,N,N-trimethylammonium chloride; DOTAP, 1,2-dioleyloxy-3- (trimethylammonio)propane; and DOTB, 1,2-dioleyl-3-(4'-trimethylammonio)butanoyl-sn-glyceroI.
• Polycationic amino acids such as polylysine, and polyarginine are also contemplated.
• emulsification requires large amounts of energy to convert a two-phase immiscible system into a suspension of discontinuous small droplets of hydrophobic fluid in an aqueous continuous phase. Fluorocarbon emulsification may be carried out generally by either of two general processes that provide energy to the system to break up the fluorocarbon volume into small droplets.
• a probe In sonication emulsification, a probe is inserted into the mixture of fluorocarbon, emulsifier, and aqueous phase, and bursts of energy are released from the tip of the probe.
• mechanical emulsification such as the process performed by a MICROFLUIDIZER apparatus (Microfluidics, Newton, MA 02164)
• streams of the mixed emulsion components are directed through the apparatus at high velocity and under high pressure (e.g. 15,000 psi), and the mechanical stress applied to the fluid produces high shear force or cavitation that produces the emulsion.
• an oil-in-water emulsion may be formed in an appropriate vessel.
• the oil employed is preferably a fluorocarbon (e.g., perfluorooctyl bromide, perfluorodecalin) which is emulsified using a surfactant such as a long chain saturated phospholipid.
• the selected amount of phospholipid may be homogenized in a predetermined volume of hot distilled water (e.g., 60°C) using a suitable high shear mechanical mixer (e.g., Ultra-Turrax model T-25 mixer) at 8000 rpm for 2 to 5 minutes.
• an appropriate amount of fluorocarbon (depending on the selected final w/v) is added slowly to the dispersed surfactant solution while mixing.
• the resulting perfluorocarbon in water emulsion is then processed using a high pressure homogenizer to reduce the particle size.
• the emulsion is processed at 12,000 to 18,000 psi for 5 discrete passes and kept at 50 to 80°C.
• the aqueous phase of the emulsion may have components dissolved therein which give the emulsion desirable properties.
• it may comprise an osmotic agent to bring the emulsion to physiological isotonicity.
• the osmotic agent may be sodium chloride, or it may be a polyhydroxyl compound, such as, for example, a sugar or ma ⁇ nitol.
• the aqueous phase may also contain soluble buffering agents.
• the lipid phase of the emulsion may also have components dissolved therein.
• a phosphatid ⁇ l choline emulsifier may have glycerol, phosphatidyl glycerol, other phosphoiipids or cholesterol admixed, and further contain an antioxidant substance, such as a tocopherol, to protect against lipid oxidation.
• fluorocarbon emulsions have been produced commercially for use as intravascular oxygen carriers. These include a mixed decalin emulsion formerly sold by Alpha Therapeutics Corp., Los Angeles, California, under the trademark FLUOSOL, and perflubron-based emulsions being developed by Alliance Pharmaceutical Corp. of San Diego, California, under the trademark OXYGENTTM. It will be appreciated that each of the foregoing compositions are particularly compatible with the methods of the present invention.
• Hemoglobin compositions contemplated for use in the present invention are well known. Such compositions are disclosed, for example, in the following U.S. Patents, which are hereby incorporated by reference: U.S. Patent Nos.4,911,929; 4,861,867; 4,857,636; 4,777,244; 4,698,387; 4,600,531; 4,526,715; 4,473,494; and 4,301,144.
• Plasma expanders may be optionally used together with the synthetic oxygen carrier.
• Various materials have been used successfully as plasma expanders which are administered using well known methods to maintain the patient's blood volume in the normal range and to encourage the increase in cardiac output where insufficient blood volume may be a factor in the condition being treated (e.g., during or following surgery where risk of developing emboli is increased).
• These include the well-known categories of crystalloid compositions (e.g., Ringers-lactate and saline (0.9%), both from Baxter Healthcare Corp., Deerfield, IL) and colloid compositions.
• Physiologically acceptable crystalloid compositions comprise aqueous solutions or suspensions of inorganic and organic components normally found in blood or derived from salts that are compatible with human physiology, osmolarity agents and an optionally an oxygen carrier (i.e., a hemoglobin substitute).
• the organic components include, for example, glucose (90 mEq/L) and amino acids (30 mEq/L) or ami ⁇ o acid analogs such as those disclosed in U.S. Patent No. 5,114,932.
• the inorganic components are included in physiological concentrations, such as for example, sodium (142 mEq/L), chloride (103 mEq/L), potassium (4 mEq/L), calcium (5 mEq/L), magnesium (3 mEq/L), bicarbonate (28 mEq/L), phosphate (4 mEq/L), sulfate (1 mEq/L).
• physiological concentrations such as for example, sodium (142 mEq/L), chloride (103 mEq/L), potassium (4 mEq/L), calcium (5 mEq/L), magnesium (3 mEq/L), bicarbonate (28 mEq/L), phosphate (4 mEq/L), sulfate (1 mEq/L).
• the osmolarity agents include disaccharides, such as maltose, lactose, sucrose or cellobiose, to achieve an osmolarity of about 400 to about 800 miliiosmoles/L
• the oxygen carriers are fluorocarbons, such as those described above, or hemoglobin substitutes, including for example ⁇ , ⁇ and ⁇ cyclodextrins, such as those described in U.S. Patent No. 5,114,392.
• Buffering agents (acids, bases or buffers) sufficient to adjust the pH of the solution to physiologically acceptable levels may also be included.
• colloid compositions include: (1) modified fluid gelatins (such as PLASMAGELTM from R. Bellon Lab. (Neuilly-sur Seine, France), GELIFUNDOLTM from Biotest (Frankfurt, Germany), GELOFUSINETM from Braun (Melsoder, Germany) and HAEMACELTM from Hoechst-Roussel Pharmaceutical Inc.
• modified fluid gelatins such as PLASMAGELTM from R. Bellon Lab. (Neuilly-sur Seine, France), GELIFUNDOLTM from Biotest (Frankfurt, Germany), GELOFUSINETM from Braun (Melsoder, Germany) and HAEMACELTM from Hoechst-Roussel Pharmaceutical Inc.
• dextran solutions such as dextran-70 solution or MACRODEXTM and dextran-40 solution or RHEOMACRODEXTM, both from Pharmacia (Piscataway, NJ);
• albumin solutions such as ALBUTEINTM from Alpha Therapeutics (Los Angeles, CA) and 5% human serum albumin from Abbott Labs (North Chicago, IL);
• starch solutions such as hydroxyethylstarch or hetastarch solution, available as HAESTM from Fresenius (Hamburg, Germany) and HESPANTM from DuPont (Willmington, DE).
• Plasma expanders can be used separately but in conjunction with, or as a carrier for, the oxygen carrier and/or additional bioactive agents used in accordance with the methods of the present invention.
• a patient suspected of having tissue hypoxia due to localized ischemia resulting from the occlusion is administered a synthetic oxygen carrier, such as any of the compounds described above.
• the synthetic oxygen carrier is a perfluorocarbon-in-water emulsion that contains a discontinuous perfluorocarbon phase of sufficiently small size to enter a blood vessel, particularly a capillary, and pass by the embolus occluding the vessel.
• Synthetic oxygen carriers with compatible intravascular persistence for the dosage administered can readily be determined by those skilled in the art using standard clinical procedures.
• the procedure may include limited removal of a portion of the patient's blood to accommodate the volume of synthetic oxygen carrier introduced into the patient.
• sufficient synthetic oxygen carrier may be administered intravenously in a fluid to permit regulation of cardiac output in order to maintain oxygen delivery at a level at least approximately equivalent to normal physiological levels.
• This intravenous fluid may include an oxygen carrier other than red blood cells, preferably a biocompatible fluorocarbon emulsion of the type discussed above, or known hemoglobin-containing blood substitutes as the oxygen carrier.
• the intravenous fluid may also include a plasma expander, such as a colloid or crystalloid.
• the emulsions of the present invention may be administered intramuscularly, intraperitoneall ⁇ , orally or topically to provide oxygen, and/or any incorporated bioactive agent to desired site.
• Such methods of administration may be applicable, for example, during ocular surgery.
• the volume of administered emulsion may vary based on clinical parameters. That is, while it will depend ultimately upon the duration and other particulars of the therapeutic regimen, the volume of intravenous fluid administered to the patient may be at least about equal to 0.1 %, preferably at least about 1 % to 20%, and more preferably up to about 20-30% of the patient's normal blood volume, which can readily be determined by the patient's weight and physiologic condition. Alternatively, the volume of intravenous fluid administered to the patient is adequate to replace any blood removed from the patient either by injury or to reduce the patient's blood volume as discussed above.
• the invention comprises treatment of a condition involving the chronic or long term administration of an oxygen carrier, the individual doses may be much smaller. In such cases, the oxygen carrier may be administered in a relatively dilute form in a continuous infusion or repeatedly administered in a more concentrated form intermittently or periodically over a period of days, weeks, months or even years.
• the intravenous fluid may comprise both plasma expander and oxygen carrier.
• the volume ratio of expander to an oxygen carrier can range from 1:1 to at least 10:1, depending on whether the fluid is a crystalloid or a colloid, and on the composition of the oxygen carrier, the concentration of the oxygen carrier, P0 2 and cardiac output. These ranges are most desirable when using a high concentration fluorocarbon emulsion, having at least about 40% w/v, preferably at least about 50% w/v, and more preferably about 60% w/v fluorocarbon (or up to 90% w/v for situations where small volume doses are desirable).
• a major portion of the intravenous fluid is a plasma expander and a minor portion is the oxygen carrier.
• the amount of perfluorocarbon administered to the patient is from about 0.5 g PFC/kg to about 10 g PFC/kg, preferably about 1 to 5 g PFC/kg. Simple calculation provides the preferred volume of emulsion when different concentrations of fluorocarbon are used.
• a breathing gas enriched in oxygen may be administered, in such embodiments the oxygen concentration is preferably at least 50-60%, and more preferably up to 100%.
• the effects of the enriched breathing gas, the oxygen carrier, and the dissolved oxygen in the aqueous portion of the circulating intravascular fluid all combine to supply enhanced levels of oxygen to the patient, particularly to the hypoxic or ischemic tissue downstream from the blood vessel occlusion.
• the collective contributions of these factors to oxygen delivery in the patient are known and have been described by the Fick equation which is discussed in U.S. Patent No. 5,451,205 incorporated herein by reference.
• the patient may be treated for a solid occlusion using standard clinical methods as determined by the treating physician (e.g., surgical bypass of the blocked vessel, removal or dissolving the embolus by mechanical and/or enzymatic means).
• the intravenous oxygen carrier can be used to provide oxygen to hypoxic tissue having blood supply blocked by such emboli and may be prior to, during and/or after such treatment to remove the occlusion. Because of the urgency of treating hypoxic or ischemic tissue, particularly heart or nervous tissue, to ameliorate tissue damage resulting from the emboli, treatment with intravenous oxygen carrier is preferably begun as soon as occlusion is detected or suspected.
• this type of acute treatment involves intravenous administration of a synthetic oxygen carrier during the first 5 in to hour of therapy, and may continue for about 24 hr to about seven days, depending on the patient's condition and additional treatment of the occlusion.
• a synthetic oxygen carrier for intravenous administration of a synthetic oxygen carrier during the first 5 in to hour of therapy, and may continue for about 24 hr to about seven days, depending on the patient's condition and additional treatment of the occlusion.
• about 0.50 to 1 ml/kg, up to about 50 ml/kg of a perfluorocarbon emulsion is administered by injection or infusion during the first hour of therapy.
• additional volumes e.g., about 2 ml/kg to about 10 ml/kg
• administration of the synthetic oxygen carrier is continued until the physician has determined that the vessel is no longer occluded.
• the present invention further comprises the chronic or long term treatment of ischemic or hypoxic conditions.
• a "chronic or long term condition" is one which lasts for a relatively long time or is marked by frequent recurrence.
• a chronic or long term condition is one in which the patient will benefit from a therapeutic regimen comprising a treatment period of longer than one week. That is, in the present invention chronic or long term conditions will be those which benefit from the administration of oxygen carrier for more than one week.
• the selected oxygen carrier may be administered intermittently, periodically or continuously over a period of days, weeks, months or even years. These conditions may be contrasted with more acute conditions (such as a heart attack or stroke) that benefit from immediate and substantial treatments such as those described immediately above.
• the absolute amount of oxygen carrier per dose is preferably reduced below the amounts appropriate for the acute treatments described above.
• the oxygen carrier may be administered once a day or once a week for as long as necessary to ameliorate or retard the effects of the ischemic or hypoxic conditions.
• the oxygen carrier may be administered intermittently as needed (i.e. as determined by clinical indicators) for as long as necessary. While such chronic therapeutic regimens can be used in conjunction with any hypoxic or ischemic condition such as atherosclerosis, they may be particularly effective for treating neurodegenerative disorders.
• the methods disclosed herein may preferably be used to treat chronic neurodegenerative conditions such as those arising from intermittent strokes, Alzheimer's disease, Parkinson's disease or epilepsy.
• drugs can be simultaneously delivered with the synthetic oxygen carrier treatment. That is, drugs can be administered separate from, but simultaneously with, administration of the oxygen carrier, or a combination of the synthetic oxygen carrier and therapeutic drugs may be administered to treat hypoxia or ischemia. Moreover, at different stages of treatment or for treatment of hypoxia in particular tissues, different combinations of drugs and oxygen carrier may be used.
• the oxygen carrier composition may also include a drug to promote dissolving the solid obstruction such as streptokinase or tPA.
• the oxygen carrier composition may include a drug that is specifically directed to the hypoxic tissue such as a neuroprotective agent for an occlusion of a vessel that supplies blood to CNS tissue.
• the oxygen carrier is fluorocarbon, and more preferably is a perfluorocarbon emulsion.
• compatible bioactive agents may comprise antibiotics, antivirals, anti- inflammatories, steroids, antihistaminics, histamine antagonists, leukotriene inhibitors or antagonists, anticholinergics, antineoplastics, anesthetics, enzymes, cardiovascular agents, genetic material including DNA and RNA, viral vectors, immunoactive agents, imaging agents, vaccines, immunosuppressive agents, peptides, proteins and combinations thereof.
• Particularly preferred bioactive agents comprise anti-inflammatories, neuroprotectants and vasodilators.
• peptides and proteins are particularly preferred.
• Exemplary medicaments or bioactive agents may be selected from, for example, analgesics, e.g. codeine, dihydromorphine, ergotamine, fentanyl, or morphine; anginal preparations, e.g. diltiazem; mast cell inhibitors, e.g. cromolyn sodium; antiinfectives, e.g. cephalosporins, macrolides, quinolines, penicillins, streptomycin, sulphonamides, tetracyclines and pentamidine; antihistamines, e.g. methapyrilene; anti-inflammatories, e.g.
• analgesics e.g. codeine, dihydromorphine, ergotamine, fentanyl, or morphine
• anginal preparations e.g. diltiazem
• mast cell inhibitors e.g. cromolyn sodium
• antiinfectives e.
• fluticasone propionate beclomethasone dipropionate, flunisolide, budesonide, tripedane, cortisone, prednisone, prednisilone, dexamethasone, betamethasone, or triamcinolone acetonide; antitussives, e.g. noscapine; bronchodilators, e.g. ephedrine, adrenaline, fenoterol, formoterol, isoprenaline, metaproterenol, salbutamol, albuterol, sal eterol, terbutaline; diuretics, e.g. amiloride; anticholinergics, e.g.
• ipatropiu ipatropiu , atropine, or oxitropium
• lung surfactants e.g. Surfaxin, Exosurf, Survanta
• xanthines e.g. aminophyliine, theophylline, caffeine
• therapeutic proteins and peptides e.g.
• bioactive agents that comprise an RNA or DNA sequence, particularly those useful for gene therapy, genetic vaccination, genetic tolerization or antisense applications, may be incorporated in the disclosed dispersions as described herein.
• Representative DNA piasmids include, but are not limited to pCMV ⁇ (available from Genz ⁇ me Corp, Framington, MA) and pCMV- ⁇ -gal (a CMV promotor linked to the E. coli Lac-Z gene, which codes for the enzyme ⁇ - galactosidase).
• formulations according to the invention may, if desired, contain a combination of two or more bioactive agents. These individual agents could be added to the emulsion in any desired proportion and placed in delivery systems as described herein.
• bioactive agents may be incorporated in the disclosed stabilized dispersions. Accordingly, the list of preferred bioactive agents above is exemplary only and not intended to be limiting. It will also be appreciated by those skilled in the art that, the proper amount of bioactive agent and the timing of the dosages may be determined for the formulations in accordance with already-existing information and without undue experimentation.
• the methods of this invention are useful for preventing or treating hypoxic or ischemic conditions that result from solid emboli that result from naturally occurring disease conditions such as atherosclerosis, or that result from dissection of intimal lining of a blood vessel as can occur following a mechanical procedure such as catheterization or percutaneous angioplasty.
• the method of this invention is also useful for amelioration of tissue damage that occurs when ischemic or hypoxic conditions due to solid emboli are detected or suspected, but before treatment can be completed to remove the emboli. This can be especially important in preventing memory loss or confusion or other neurologic complications and adverse outcomes associated with cerebral emboli or stroke, or for preventing cardiac muscle damage associated with AMI or low-flow myocardial ischemia.
• the method of the present invention are also useful for delivery of therapeutic drugs as an adjunct for ameliorating tissue damage resulting from ischemia.
• a perfluorocarbon emulsion suitable for use is a 90% (w/v) perflubron emulsion having the following formula prepared and sterilized using standard methods known to those skilled in the art:
• this emulsion may be used in conjunction with the teachings herein to prevent or treat tissue hypoxia or ischemia, provide neuroprotection or retard neurodegeneration, provide for chronic or long-term therapeutic regimens and mediate the delivery of bioactive agents.

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• 1998
  • 1998-10-23 AU AU11179/99A patent/AU1117999A/en not_active Abandoned
  • 1998-10-23 EP EP98953931A patent/EP1023058A2/de not_active Withdrawn
  • 1998-10-23 WO PCT/US1998/022491 patent/WO1999021541A2/en not_active Application Discontinuation

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