WO1998043637A1

WO1998043637A1 - Peroxynitrite decomposition catalyst

Info

Publication number: WO1998043637A1
Application number: PCT/US1998/005567
Authority: WO
Inventors: Dennis P. Riley; Daryle H. Busch; Xiaoping Zhang
Original assignee: Monsanto Company; University Of Kansas
Priority date: 1997-04-01
Filing date: 1998-03-26
Publication date: 1998-10-08
Also published as: WO1998043637A9; AU6939898A

Abstract

A class of complexes having the formula M(R)X2Y, where M is a transition metal, X is halogen, Y is a pharmaceutically acceptable counterion or ligand, and R is meso-2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]-heptadeca-1(17), 13, 15-triene, is an effective catalyst for the decomposition of peroxynitrite at physiological pH.

Description

PEROXYNITRITE DECOMPOSITION CATALYST

Technical Field

This invention relates to compositions and methods for the decomposition of peroxynitrite in the bodies of humans and lower animals in need of such treatment. Background Art

Nitric oxide has been shown to be an important messenger in many vertebrate signal transduction processes. This free-radical gas is produced in the body from arginine in a complex reaction that is catalyzed by nitric oxide synthase (NOS). Nitric oxide diffuses freely across cellular membranes but has a short life, less than a few seconds, because it is highly reactive. Hence, NO is well suited to serving as a transient signal molecule within cells or between adjacent cells. It is known to serve as the endothelium-derived vascular relaxing factor (EDRF), and is protected from breakdown by superoxide dismutase. Numerous published papers highlight the central role of superoxide radicals

(Ch'^~) in many disease states. This highly reactive moiety poses a serious oxygen toxicity challenge to the entire organism, and this toxicity is manifested in a variety of forms. The toxicity of superoxide radicals is so significant, and its management is so fundamental to survival, that Stanford University biochemist Lubert Stryer, in his classic textbook Biochemistry, stated "Superoxide dismutase is an essential molecular adaptation to the challenge posed by an oxygen atmosphere" [4^m ed., p. 554 (1995) (emphasis added)].

The body has a mechanism for handling superoxide, the superoxide dismutase (SOD) enzyme. However, in addition to the direct toxicity of superoxide radicals, they also exert an indirect toxicity by reacting rapidly and spontaneously with nitric oxide to yield peroxynitrite. This reaction not only destroys nitric oxide, but also provides a path for forming peroxynitrous acid, a precursor of the toxic hydroxyl radical. The macrophage immune response and other pathological conditions, such as endotoxic shock and ischemia/reperfusion injury, which raise concentrations of both nitric oxide and superoxide, can generate significant levels of peroxynitrite in vivo.

Peroxynitrite and its conjugate acid are capable of nitrating tyrosine residues in proteins and oxidizing DNA, lipids, sulfhydryls, and methionine. It also inactivates superoxide dismutase, further exacerbating the problem of toxic free-radical oxidants. Thus, a need exists beyond superoxide dismutase and compounds having similar functions to deal with other aspects of this cascade of toxic oxidants. A compound that could catalyze the decomposition of peroxynitrite would not only deal with another portion of the cascade, but also preserve superoxide dismutase to deal with other aspects of the problem. An ideal catalyst would be able to decompose peroxynitrite without releasing harmful hydroxyl radicals. Brief Description of the Drawings

The Figure is a graph illustrating the results of testing a complex of the present invention in an animal model of inflammation. Disclosure of the Invention

It has now been determined that a complex first identified over twenty years ago, of a class of complexes having the formula M(R)X₂Y, where M is a transition metal, X is halogen, Y is a pharmaceutically acceptable counterion or ligand, and R is meso-2,12-dimethyl-3,7,l l, 17-tetraazabicyclo[11.3.1]-heptadeca-l(17), 13, 15-triene, is an effective catalyst for the decomposition of peroxynitrite at physiological pH. These complexes are soluble in water and stable at physiological pH. Thus, the present invention provides a pharmaceutical composition in unit dosage form for treating a human patient having a medical condition that is advantageously affected by increased decomposition of peroxynitrite, comprising an amount per dosage unit of a metal complex peroxynitrite decomposition catalyst of the formula M(R)X2Y, where M is a transition metal, X is halogen, Y is a pharmaceutically acceptable counterion or ligand, and R is meso-2,12-dimethyl-3,7, l l, 17-tetraazabicyclo[11.3.1]-heptadeca-l(17), 13, 15-triene, sufficient to increase peroxynitrite decomposition, or the rate of peroxynitrite decomposition, in such patient.

The invention further provides a method for treating a human patient having a medical condition that is advantageously affected by increased decomposition of peroxynitrite, comprising an amount per dosage unit of a metal complex peroxynitrite decomposition catalyst of the formula M(R)X₂Y, where M is a transition metal, X is halogen, Y is a pharmaceutically acceptable counterion or ligand, and R is meso-2,12- dimethyl-3,7,ll,17-tetraazabicyclo[11.3.1]-heptadeca-l(17), 13, 15-triene, sufficient to increase peroxynitrite decomposition in such patient. Treatable conditions within the scope of this invention include ischemic reperfusion injury, such as occurs in stroke, head trauma, mesenteric infarction, tourniquet injury, pulmonary embolism, fat embolism from long bone fractures, myocardial infarction and myocardial ischemia; side effects from cancer chemotherapy; chronic or acute inflammation, including arthritis and inflammatory bowel disease; sepsis; multiple sclerosis; Alzheimer's disease; Parkinson's disease; adult respiratory distress syndrome; sleep apnea; bronchopulmonary dysplasia; diabetic peripheral vascular disease; familial amyotrophic lateral sclerosis; cardioplegia; preservation of organs for transplantation; induced hypotension for neurosurgery; and intravenous regional anesthesia ("Bier block"). Modes for Carrying Out the Invention

Useful transition metals are iron, manganese, nickel, copper and vanadium. Iron is highly preferred for its relatively low toxicity.

In highly preferred embodiments, the complex has the formula Fe(R)ChBF4 or [Fe(R)Ch]Cl, i.e., where M is Fe(III), X and Y are both chloride or chloride and BF₄, respectively, and R is meso-2,12-dimethyl-3,7,l l,17-tetraazabicyclo[11.3.1]- heptadeca-l(17), 13, 15-triene. The complex in which Y is chloride is known and can be prepared as reported by Riley et al., Inorg. Chem., 14, 490 (1975). In these complexes, iron (III) is coordinated to four nitrogen atoms of the ligand and the fifth and sixth position are occupied by two chloride ions. In aqueous solution, the chloride ions are displaced by water molecules (aquo groups). Around neutral pH, the dominant species appears to be [Fe(R)(H O)(OH)] ⁺.

The decomposition of peroxynitrite by Fe(R)ChBF4 is so rapid that the second order rate constant could not be measured using a conventional HP 8452A spectrophotometer and was determined using stopped-flow measurements. The second order rate constants for the catalyzed reaction exhibit a bell-shaped pH profile. Two parallel pathways have been defined, based on either the active species [Fe(R)(H₂O)(OH)]²⁺ and ONOO or [Fe(R)(OH)₂]⁺ and HOONO giving the rate constants of (9± 1) x 10⁴ M^"1 s^"1. The kinetically obtained pK« (HOONO → H⁺ + OONO ) of 6.71 ±0.07 and pK_ of 7.49±0.08 (Fe(R)(OH)₂O)(OH) → (Fe(R)(OH)₂ + H⁺) are in good agreement with the thermodynamically obtained pK» of 6.83+0.05 and pK2 of 7.39±0.02, respectively, suggesting the formation of a high-valent iron-oxo intermediate at acidic pH. While not intending to be limited by theory, it appears that the pKa near neutral pH for the coordinated water molecule in [Fe(R)(H₂O)(OH)]²⁺ may be critically important to the ability of the complex to function as a peroxynitrite decomposition catalyst. The yield of nitrate anion is enhanced in the presence of Fe(R)Ch⁺ compared with the uncatalyzed reaction under the same conditions, and the concentration of nitrate anion increases with increasing pH in the presence of Fe(R)Ch⁺.

By pharmaceutically acceptable counterions and ligands is meant those counterions and ligands which are safe for systemic administration. These counterions include halide, oxo, aquo, hydroxo, alcohol, phenol, dioxygen, peroxo, hydroperoxo, alkylperoxo, arylperoxo, ammonia, alkylamino, arylamino, heterocycloalkyl amino, heterocycloaryl amino, amine oxides, hydrazine, alkyl hydrazine, aryl hydrazine, nitric oxide, cyanide, cyanate, thiocyanate, isocyanate, isothiocyanate, alkyl nitrile, aryl nitrile, alkyl isonitrile, aryl isonitrile, nitrate, nitrite, azido, alkyl sulfonic acid, aryl sulfonic acid, alkyl sulfoxide, aryl sulfoxide, alkyl aryl sulfoxide, alkyl sulfenic acid, aryl sulfenic acid, alkyl sulfinic acid, aryl sulfmic acid, alkyl thiol carboxylic acid, aryl thiol carboxylic acid, alkyl thiol thiocarboxylic acid, aryl thiol thiocarboxylic acid, alkyl carboxylic acid (such as acetic acid, trifluoroacetic acid, oxalic acid), aryl carboxylic acid (such as benzoic acid, phthalic acid), urea, alkyl urea, aryl urea, alkyl aryl urea, thiourea, alkyl thiourea, aryl thiourea, alkyl aryl thiourea, sulfate, sulfite, bisulfate, bisulfite, thiosulfate, thiosulfite, hydrosulfite, alkyl phosphine, aryl phosphine, alkyl phosphine oxide, aryl phosphine oxide, alkyl aryl phosphine oxide, alkyl phosphine sulfide, aryl phosphine sulfide, alkyl aryl phosphine sulfide, alkyl phosphonic acid, aryl phospho ic acid, alkyl phosphinic acid, aryl phosphinic acid, alkyl phosphinous acid, aryl phosphinous acid, phosphate, thiophosphate, phosphite, pyrophosphite, triphosphate, hydrogen phosphate, dihydrogen phosphate, alkyl guanidino, aryl guanidino, alkyl aryl guanidino, alkyl carbamate, aryl carbamate, alkyl aryl carbamate, alkyl thiocarbamate aryl thiocarbamate, alkyl aryl thiocarbamate, alkyl dithiocarbamate, aryl dithiocarbamate, alkyl aryl dithiocarbamate, bicarbonate, carbonate, perchlorate, chlorate, chlorite, hypochlorite, perbromate, bromate, bromite, hypobromite, tetrahalomanganate, tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, hypophosphite, iodate, periodate, metaborate, tetraaryl borate, tetra alkyl borate, tartrate, salicylate, succinate, citrate, ascorbate, saccharinate, amino acid, hydroxamic acid, thiotosylate, and anions of ion exchange resins

By "safe and effective amount" is meant an amount of the complex of this inventioneffective to provide increased decomposition of peroxynitrite in the patient being treated at a reasonable benefit/risk ratio attendant with any medical treatment. The amount of the complex will vary with the particular condition being treated, the severity of the condition, the duration of the treatment, the specific formulation employed, the concentration of the complex therein, and like factors. By "systemic administration" is meant the introduction of the complex or a composition containing same into the tissues of the body, other than by topical application. Systemic administration thus includes, without limitation, intrathecal, epidural, intramuscular, intravenous, intraperitoneal, and subcutaneous administration. By the term "comprise" as used herein is meant that various other inert ingredients, compatible drugs and medicaments, and steps can be employed in the compositions and methods of the present invention as long as the complex is present in the compositions and are used in the manner disclosed. The term "comprising" thus encompasses and includes the more restrictive terms "consisting essentially of" and "consisting of" which characterize the use of the essential complexes in the compositions and methods disclosed herein.

By "compatible" herein is meant that the components of the composition are capable of being commingled without interacting in a manner which would substantially decrease the efficacy of the total composition under ordinary use situations.

All percentages herein are by weight of the composition unless otherwise specified.

Because the formation of peroxynitrite and the resulting tissue injury is common to all of the aforementioned diseases, the treatment of patients with the compositions and methods of this invention will generally be the same regardless of the specific disease being treated. The dosage and route of administration may differ from case to case based upon the size and age of the patient and the severity of the disease or condition. See, for example, Hardman et al. Eds., Goodman & Gilman's THE PHARMACOLOGICAL BASIS OF THERAPEUTICS, (9^th ed., 1996):

[Tjherapy as a science does not apply simply to the evaluation and testing of new, investigational drugs in animals and human beings. It applies with equal importance to the treatment of each patient as an individual. Therapists of every type have long recognized and acknowledged that individual patients show wide variability in response to the same drug or treatment method. The practicing clinician is familiar with the approach of titrating dosage and administration regimen to the effects and side effects of the drug, the objective being prevention or improvement of the disease state while minimizing adverse reactions. In the context of this invention, the objective of the therapy in each instance will be to prevent, reduce or eliminate the injurious effects of peroxynitrite by decomposing it with the compositions of this invention.

The compositions of the present invention are useful when administered systemically, for example by parenteral administration. The dosage of the complex which is both safe and effective to significantly increase decomposition of peroxynitrite and afford relief will vary with the particular condition being treated, the severity of the condition, the duration of treatment, the specific complex employed and its usage concentration, and like factors within the specific knowledge and expertise of the patient or the attending physician and commensurate with a reasonable benefit/risk ratio associtated with the use of any drug. The systemic dosages and dosage ranges given herein are based on delivery of the complex to a 70 kg human and can be adjusted to provide equivalent dosages for patients of different body weights.

For mammals, especially humans, individual doses of from about 0.1 mg to about 100 mg per kilogram with total dosages of from about 1 mg to about 500 mg per kilogram are acceptable. Individual doses of from about 5 mg to about 500 mg per kilogram with total dosages of from about 100 mg to about 1000 mg per kilogram are preferred. Individual doses of from about 5 mg to about 50 mg with total dosages of from about 10 mg to about 500 mg are especially preferred. While dosages higher than the foregoing are effective, toxicity and side effects will present problems in some individuals. The complexes of this invention can be administered parenterally in combination with a pharmaceutically acceptable carrier such as water or saline. Other parenteral vehicles such as vegetable oil, Cremophor EL, or sterile, pyrogen-free water and a water-miscible solvent (e.g. ethyl alcohol) at a practical amount of the complex per dose can also be used. Parenteral administration can be by subcutaneous, intradermal, intramuscular, intrathecal, intraarticular, or intravenous injection.

With regard to pharmaceutical compositions for systemic administration, the term "pharmaceutically acceptable carrier" also denotes a solid or liquid filler, diluent, or encapsulating substance. Some examples of the substances which can serve as pharmaceutical carriers for the complexes of the present invention include: sugars such as lactose, glucose and sucrose; starches such as corn starch and potato starch; cellulose and its derivatives, such as sodium carboxymethylcellulose, ethyl cellulose, cellulose acetate; powdered tragacanth; malt; gelatin; talc, stearic acid, magnesium stearate; calcium sulfate; vegetable oils, such as peanut oil, cottonseed oil, sesame oil, olive oil, corn oil and oil of theobroma; polyols such as propylene glycol, glycerin, sorbitol, mannitol, and polyethylene glycol; agar; alginic acid; pyrogen-free water; isotonic saline; phosphate and other buffer solutions; cocoa butter (suppository base), emulsifiers, such as the Tweens^® as well as other non-toxic compatible substances typically used in pharmaceutical formulations. Wetting agents and lubricants such as sodium lauryl sulfate, as well as coloring agents, flavoring agents and preservatives, can also be present.

The pharmaceutical carrier employed in conjunction with the complex is used at a concentration sufficient to provide a practical size to dosage relationship. Preferably, the pharmaceutical carrier comprises at least about 98% by weight of the total composition. Animal Tests Carrageenan paw edema

Male Sprague-Dawley rats (175-200 g, Harlan Sprague Dawley, Indianapolis, IN, USA) were housed and cared for under the guidelines of the institutional animal care and use committee. They received a subplantar injection of carrageenan (0.1 ml of a 1 % suspension in 0.85% saline) into the right hind paw. Paw volume was measured using a plethysmometer (Ugo-Basile, Varese, Italy) immediately prior to the injection of carrageenan and thereafter at hourly intervals for 6h. Edema was expressed as the increase in paw volume (ml) after carrageenan injection relative to the pre-injection value for each animal. Complexes were administered intravenously at 60 minutes after carrageenan. Results with the complex [Fe(R)Ch]Cl, designated SC- 72319, are shown in the drawing Figure.

Claims

WHAT IS CLAIMED IS:

1. A pharmaceutical composition in unit dosage form for treating a human patient having a medical condition that is advantageously affected by increased decomposition of peroxynitrite, comprising an amount per dosage unit of a metal complex peroxynitrite decomposition catalyst of the formula M(R)XΓêæY, where M is a transition metal, X is halogen, Y is a pharmaceutically acceptable counterion or ligand, and R is meso-2,12-dimethyl-3,7,l l,17- tetraazabicyclo[11.3.1]-heptadeca-l(17), 13, 15-triene, sufficient to increase peroxynitrite decomposition in such patient.

2. A pharmaceutical composition in unit dosage form for the treatment of a human patient having a medical condition selected from ischemic reperfusion injury; stroke; head trauma; mesenteric infarction; tourniquet injury; pulmonary embolism; fat embolism from long bone fractures; myocardial infarction and myocardial ischemia; side effects from cancer chemotherapy; chronic inflammation; acute inflammation; arthritis; inflammatory bowel disease; sepsis; multiple sclerosis; Alzheimer's disease; Parkinson's disease; adult respiratory distress syndrome; sleep apnea; bronchopulmonary dysplasia; diabetic peripheral vascular disease; familial amyotrophic lateral sclerosis; cardioplegia; preservation of organs for transplantation; induced hypotension for neurosurgery; and intravenous regional anesthesia, comprising an amount per dosage unit of a metal complex peroxynitrite decomposition catalyst of the formula M(R)X₂Y, where M is a transition metal, X is halogen, Y is a pharmaceutically acceptable counterion or ligand, and R is meso-2,12-dimethyl- 3,7, l l,17-tetraazabicyclo[11.3.1]-heptadeca-l(17), 13, 15-triene, sufficient to increase peroxynitrite decomposition in such patient.

3. A composition according to Claim 1 wherein the metal is selected from the group consisting of Mn, Fe, Ni and V.

4. A composition according to Claim 3 wherein X is chloride.

5. A composition according to Claim 3 wherein Y is chloride.

6. A composition according to Claim 3 wherein the metal is Fe(III).

7. A method of treating a human patient having a medical condition that is advantageously affected by increased decomposition of peroxynitrite, comprising administering to the patient an amount of a metal complex peroxynitrite decomposition catalyst of the formula M(R)X₂Y, where M is a transition metal, X is halogen, Y is a pharmaceutically acceptable counterion or ligand, and R is meso-2,12-dimethyl-3,7,ll, 17-tetraazabicyclo[11.3.1]- heptadeca-l(17), 13, 15-triene, sufficient to increase peroxynitrite decomposition in such patient.

8. A method of treating a human patient having a medical condition selected from ischemic reperfusion injury; stroke; head trauma; mesenteric infarction; tourniquet injury; pulmonary embolism; fat embolism from long bone fractures; myocardial infarction and myocardial ischemia; side effects from cancer chemotherapy; chronic inflammation; acute inflammation; arthritis; inflammatory bowel disease; sepsis; multiple sclerosis; Alzheimer's disease; Parkinson's disease; adult respiratory distress syndrome; sleep apnea; bronchopulmonary dysplasia; diabetic peripheral vascular disease; familial amyotrophic lateral sclerosis; cardioplegia; preservation of organs for transplantation; induced hypotension for neurosurgery; and intravenous regional anesthesia, comprising administering systemically to the patient an amount of a metal complex peroxynitrite decomposition catalyst of the formula M(R)X2Y, where M is a transition metal, X is halogen, Y is a pharmaceutically acceptable counterion or ligand, and R is meso-2,12-dimethyl-3,7, 11,17- tetraazabicyclo[11.3.1]-heptadeca-l(17), 13, 15-triene sufficient to increase peroxynitrite decomposition in such patient.

9. A method according to Claim 7 wherein the metal is selected from the group consisting of Mn, Fe, Ni and V.

10. A method according to Claim 9 wherein X is chloride.

11. A method according to Claim 9 wherein Y is chloride.

12. A method according to Claim 9 wherein the metal is Fe(III).