WO1994026279A1 - Bisphosphonate esters for treating gastric disorders - Google Patents

Abstract

A use of bisphosphonate esters for the treatment of gastric diseases characterized by irritation, ulceration and acid hypersecretion and are useful as cytoprotective agents against gastric irritation and ulceration comprising the administration of bisphosphonate esters, acids or pharmaceutically acceptable salts thereof to a patient in need thereof.

Description

BISPHOSPHONATE ESTERS FOR TREATING GASTRIC DISORDERS

Cross-Reference to Related Applications

This application is a continuation of U.S. Serial No. 08/063,758, filed 18 May 1993. Background of the Invention

The subject invention is directed toward the discovery that bisphosphonate esters are useful in the treatment of gastric diseases characterized by irritation, ulceration and acid hypersecretion and are useful as cytoprotective agents against gastric irritation and ulceration. Previously, this class of chemical compounds was known to be useful for the treatment of arthritis and cardiovascular diseases and; therefore, the discovery that these compounds are useful in treating gastric diseases is unexpected.

The present invention comprises the use of these compounds in humans and lower animals as a safe and effective treatment of diseases characterized by irritation, ulceration and acid hypersecretion in the gastric tract.

Description of the Related Art

PCT International Application PCT/US92/05398; WO 93/01198 (21 January 1993) discloses the preparation and structures for bisphosphonate esters having a pyrazolopyrimidine and pyrimidinyl heterocyclic structure useful as anti-inflammatories and anti-arthritic agents.

PCT International Application PCT/US90/01106; WO 90/12017 (18 October 1990) discloses the preparation and structures for bisphosphonate acid, esters and salts useful as anti-arthritic agents.

PCT International Application PCT/US91/05554; WO 92/03451 (5 March 1992) discloses the preparation and structures for acyclic and cyclic bisphosphonate esters useful as antiarthritic agents.

US Patent 3,683,080 and J. Org. Chem., 13 p 199-207 (1968) disclose the preparation and structure for various other bisphosphonate esters especially (dichloromethylene)bis-, phosphonic acid disodium salt which is disclosed to be useful for inhibiting anomalous deposition and mobilization of calcium phosphates in animal tissue.

Summary of the Invention

The present invention is directed toward a method for treating gastric diseases characterized by irritation, ulceration and acid hypersecretion by administering a therapeutically effective amount of a bisphosphonate ester or a pharmaceutically acceptable acid salt thereof to an animal or human in need thereof. The mode of administration can be intravenously, intramuscularly, topically, transdermally, bucally, orally or parenterally as best determined by the severity and type of patient being treated. A typical dosage depending on the route of administration can vary from about 0.001 mg to about 1.0 grams per dose. A bisphosphonate ester or a pharmaceutically acceptable acid salt thereof are generally known in the art except not as a medicament for treating gastric diseases. Typically, a bisphosphonate comprises two phosphorus atoms joined together by a carbon atom wherein each phosphorus atom has a doubly bonded oxygen and two hydroxy, alkyoxy or various other oxygen bonded groups such as those depicted for R₁, below, or combinations thereof.

Typically, the carbon atom joining the two phosphorus groups is bonded to various other chemical entities such as halogen atoms, amine groups or heterocyclic ring structures.

Representative examples of various bisphosphonate compounds are disclosed in PCT

International Application PCT/US92/05398; PCT/US90/01106; PCT/US91/05554; and US Patent 3,683,080, described above as well as Formula I shown below. Preferred bisphosphonate compounds are

a) (4-oxo-3,4-diphenylbutylidene)bis-, tetraethyl ester phosphonic acid;

b) [5-(3-fluorobenzoyl)-2,4-dihydro-3H-pyrazol-3-ylidene]bis-, tetraethyl ester phosphonic acid;

c) [4-(3-fluorophenyl)-4-oxobutylidene]bis-, tetraethyl ester phosphonic acid;

d) (4-oxo-4-phenylbutylidene)bis-, tetraethyl ester phosphonic acid;

e) (3-(3-Cyano-2,5-dimethyl-pyrazolo(1,5-a)pyrimidin-7-yl)- propylidene)bisphosphonic acid tetraethyl ester;

f) (dichloromethylene)bis-, phosphonic acid disodium salt; and

g) [3-(1,6-Dihydro-1-methyl-6-oxo-4-phenyl-2-pyrimidinyl)-propylidene] bisphosphonic acid, tetraethyl ester.

Detailed Description of the Invention

The present invention disclosed the use of bisphosphonate esters, acids and their pharmaceutically acceptable salts for treating gastric diseases characterized by irritation, ulceration, and acid hypersecretion. The bisphosphonate compounds are also useful as cytoprotective agents against gastric irritation and/or ulceration.

Typical bisphosphonate compounds that may be used in methods or treatments for gastric diseases are those disclosed in PCT/US92/05398, WO 93/01198 (21 January 1993), herein incorporated by reference; PCT/US90/01106, WO 90/12017 (18 October 1990), herein incorporated by reference; PCT/US91/05554, WO 92/03451 (5 March 1992), herein incorporated by reference; US Patent 3,683,080, herein incorporated by reference for the formula X₂C- (PO(OR₁)₂)₂ wherein X is H, F, Cl, Br, and R₁ is as defined below; and bisphosphonate esters, acids and their pharmaceutically acceptable salts which are structurally represented by Formula I:

wherein R₁ are the same or different and are selected from the group consisting of H, C₁-C₆ alkyl, C₃-C₈ cycloalkyl, CH₂Ph, or where both OR₁ on the same P are taken together along with CH₂-CH₂, CH₂-CH₂-CH₂, or CH₂-C(CH₃)₂-CH₂ to form a heterocyclic ring containing one P, two O and two to three carbon atoms;

R₂ is H, C₁-C₆ alkyl, C₃-C₈ cycloalkyl, phenyl optionally substituted with 1 or 2 phenyls, or 1 through 5 F, Cl, Br, I, NO₂, CN, CF₃, C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl, OH, SH, NH₂, C₁-C₆ alkoxy, C₁-C₆ alkylthio, or N(R₅)₂;

R₃ is H, phenyl, F, Cl, Br, I, C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl, C₁-C₆ alkoxy, C₁-C₆ alkylthio, or N(R₅)₂;

X is O or S when R₄ is phenyl or phenyl substituted with 1 or 2 phenyls, or 1 through 5 F, Cl, Br, I, NO₂, CN, CF₃, C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl, OH, SH, NH₂, C₁-C₆ alkoxy, C₁- C₆ alkylthio, or N(R₅)₂; or

X is N when R₄X is a heterocyclic ring containing n atoms of which n-1 to 1 are carbon, 1 to 3 nitrogen, 0 or 1 oxygen, or 0 or 1 sulfur where n is 5 or 6; and

R₅ is H, C₁-C₆ alkyl, C₃-C₇ cycloalkyl, phenyl or N(R₅)₂ is a heterocyclic ring of 4 to 7 members containing 3 to 6 carbons, 1 to 3 nitrogens, 0 to 2 oxygens, and 0 to 2 sulfurs.

In the structural Formula I, the carbon content of various hydrocarbon-containing moieties is indicated by a prefix designating the minimum and maximum number of carbon atoms in the moiety, i.e., the prefix C_i-C_j defines the number of carbon atoms present from the integer "i" to "j" inclusive. Thus, C₁-C₃ alkyl refers to alkyls of one to three carbon atoms, inclusive, including isomers thereof such as methyl, propyl, ethyl and isopropyl.

C₃-C₇ cycloalkyl is cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane and isomeric forms thereof.

The term "halo" includes fluoro, chloro, bromo and iodo.

C₁-C₆ alkylthio are methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio, C₁-C₆ alkylthio are methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio, and isomeric forms thereof.

C₁-C₆ alkoxy are methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, and isomeric forms thereof.

The abbreviation "Ph" means phenyl.

Pharmaceutically acceptable salts means salts useful for administering the compounds of this invention or useful forms the compounds may take in vitro and in vivo and include potassium, sodium, hydrochloride, hydrobromide, hydroiodide, sulfate, phosphate, acetate, propionate, lactate, mesylate, maleate, malonate, succinate, tartrate, citrate and the like. These salts may be in hydrated form.

The subject invention provides a method for treating gastric diseases characterized by irritation, ulceration and acid hypersecretion and are useful as cytoprotective agents against gastric irritation and ulceration by administering to an animal or human (patients) in need thereof a therapeutically effective amount of a bisphosphonate compound. Routes of administration include oral, intramuscular, intravenous, transdermal, intra-articular, subcutaneous, or intraperitoneal. An effective amount is an amount whereby the symptoms such as the pain and gastric discomfort are relieved or reduced and, for irritation or ulceration reduced or eleviated. A typical dosage is about 0.001 mg to 1.0 gram with dose determined by the particular mode of administration, use and frequency of administration.

The compounds can be administered intravenously, intramuscularly, topically, transdermally, such as by skin patches, bucally or orally to humans or animals. The

compositions of the present invention can be presented for administration in unit dosage forms, such as tablets, capsules, pills, powders, granules, sterile parenteral solutions or suspensions, oral solutions or suspensions, oil in water and water in oil emulsions containing suitable quantities of the compound, suppositories and in fluid suspensions or solutions.

For oral administration, either solid or fluid unit dosage forms can be prepared. For preparing solid compositions such as tablets, the compound can be mixed with conventional ingredients such as talc, magnesium stearate, dicalcium phosphate, magnesium aluminum silicate, calcium sulfate, starch, lactose, acacia, methylcellulose, and functionally similar materials as pharmaceutical diluents or carriers. Capsules are prepared by mixing the compound with an inert pharmaceutical diluent and filling the mixture into a hard gelatin capsule of appropriate size. Soft gelatin capsules are prepared by machine encapsulation of a slurry of the compound with an acceptable vegetable oil, light liquid petrolatum or other inert oil.

Fluid unit dosage forms for oral administration such as syrups, elixirs, and suspensions can be prepared. The forms can be dissolved in an aqueous vehicle together with sugar, aromatic flavoring agents and preservatives to form a syrup. Suspensions can be prepared with an aqueous vehicle with the aid of a suspending agent such as acacia, tragacanth,

methylcellulose and the like.

For parenteral administration, fluid unit dosage forms can be prepared utilizing the compound and a sterile vehicle. In preparing solutions, the compound can be dissolved in water for injection and filter sterilized before filling into a suitable vial or ampoule and sealing.

Adjuvants such as a local anesthetic, preservative and buffering agents can be dissolved in the vehicle. The composition can be frozen after filling into a vial and the water removed under vacuum. The dry lyophilized powder can then be sealed in the vial and reconstituted prior to use.

The compounds of Formula I can be prepared by selecting the appropriately substituted

2-amino pyrimidines synthesized by means familiar to those skilled in the art, and involve the reaction of 6-halo-2-amino pyrimidines with the desired alkoxide, phenoxide, thiophenoxide, or amine in an inert solvent such as toluene, THF, DMSO, or DMF or the solvent can be the corresponding alcohol, phenol, or thiophenol. Temperatures can range between 0°C and reflux. The preferred temperature is room temperature. If the alcohol is low molecular weight, the preferred solvent is the corresponding alcohol or else is DMF. The products are isolated by dilution with water, and collection of the solid. This material can be recrystallized if needed.

The bisphosphonates are synthesized through the reaction of the above 2-amino pyrimidines with vinylidene bisphosphonate esters, which have previously been described in published PCT Application WO 9012 017 and by Degenhardt, C.R.; Burdsall, D.C.

J.Org.Chem., 51, 3488-3490 (1986). The reaction occurs in an inert solvent, such as THF, benzene, toluene, or xylene at elevated temperatures. It is preferred that the reaction be run in toluene at reflux.

The synthesis of the corresponding acid is accomplished by a procedure which is well known to those skilled in the art. Typically, the tetraester is treated with trimethylsilyl bromide in an inert solvent such as chloroform or methylene chloride, followed by aqueous workup to isolate the acid. Preferred compounds from Formula I are as follows:

a) (2-((4-(2-fluoro-6-nitrophenoxy)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5-dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

b) (2-((4-(2,4-dilluorophenoxy)-6-methyl-2-pyrirmidinyl)amino)ethylidene)bis(2,2'-(5,5-dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

c) (2-((4-(4-morpholinyl)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5-dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

d) (2-((4-(2-,4-dibromophenoxy)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5-dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

e) (2-((4-(4-cyanophenoxy)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5- dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

f) (2-((4-phenoxy-6-methyl- 2-pyrimidinyl)amino)ethylidene)bisphosphonic acid tetraethyl ester;

g) (2-((4-(4-piperidinyl)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5-dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

h) (2-((4-(3,4-dichlorophenoxy)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5-dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

i) (2-((4-(phenylthio)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5-dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

j) (2-((4-(3-chlorophenoxy)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5-dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

k) (2-((4-(2,4-dichlorophenoxy)-6-methyl-2-pyrimidinyl)amino)ethylidene)bisphosphonic acid, tetraethyl ester; and

l) (2((4-(methyl)-6-methoxy-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5-dimethyl-2,2'- dioxide-1,3,2-dioxaphosphorphine)).

Bisphosphonate ester compounds were tested in models of gastric ulcers induced by ethanol, aspirin (+4°C), flurbiprofen (+4°C), also against gastric hypersecretion induced by ligation of the gastric pylorus. These assays demonstrated the usefulness of bisphosphonate therapy for gastric disorders or diseases not heretobefore known.

Female Sprague-Dawley (Charles River) rats of 225-255 g were used. In most experiments, they were fasted overnight in semi-restraining individual cages to prevent coprophagy. During this period, drinking water was also withheld. Their body weight after fasting was 211-241 g. The bisphosphonate compounds were given orally.

The compounds listed in Table A below, were tested for possible ulcerogenic activity. On the morning following fasting, the compounds were given orally and the animals were killed four hours later. Their stomachs were dissected out, opened along the greater curvature and randomized so that the examiner was unaware of the treatment given. The stomachs were then examined with a 5 x binocular magnifier for the presence of gastric erosions. The lesions were counted, and their average number per stomach was calculated for each group. The ulcer severity was also determined according to a scale of 0 to 3+ (0: no ulcer; 1: milder ulcers; 2: ulcers of moderate severity; 3: severe ulcers). Number of animals: 2 controls, and 6 in each of the experimental groups.

The aspirin-induced ulcer study (Table 1) was performed to determine whether the compounds exerted antiulcer activity. After an overnight fast, gastric ulcers were produced by aspirin administered orally at 50 mg/kg contained in 1 ml, homogenized in water containing

Tween 80 (1 drop/20 ml). Immediately after aspirin administration, the animals were exposed to cold temperatures (4°C) in order to increase the ulcerogenicity of aspirin. The compounds were given orally thirty minutes before aspirin and the animals were killed one hour after aspirin plus cold. Gastric ulcers were counted and scored in Table 1. There were 10 animal controls, and 6 animals in each of the experimental groups.

All compounds, except 1, were antiulcer against aspirin + cold-induced ulcers.

The reduction of gastric ulcers was 42%-84%.

The effect on gastric secretions study (Table 2) was performed to determine whether the compounds affected gastric acid secretion. The compounds were given on the morning after fasting. One hour later, the pylorus was ligated with 3-0 silk under ether anesthesia. Four hours later, the animals were killed, the esophagus was clamped, the stomach dissected out, and its contents emptied into a graduated test tube. The volume of gastric juice was measured to the nearest 0.1 ml. The acid content was titrated with 0.01 M NaOH with an automatic titrator (Zymark Robotics, Hopkinton, MA) and expressed as mEq per liter (concentration) and μEq/4 h (output). There were 10 animal controls, and 6 animals in each of the experimental groups.

All the compounds significantly reduced gastric acid secretion (volume, acid concentration and acid output). The inhibition of acid output was 52%-92%.

The possible cytoprotective effect of the compounds was tested in the ethanol-induced gastric lesion model (Table 3). On the morning after fasting, the animals were treated with the compounds. One hour later, 1 ml of 100% ethanol was given orally and the animals were killed one hour later. The gastric necrotic lesions were scored as described above and shown in Table 3. There were 10 animal controls, and 4 animals in the experimental groups.

All the compounds were cytoprotective at a dose of 100 mg/kg for 3, 4, and 200 g/kg for 1, 2, 6 and 5, against ethanol-induced lesions. The inhibition of gastric lesions was 69%-100%.

The effect of Compound 7 ([3-(1,6-Dihydro-1-methyl-6-oxo-4-phenyl-2-pyrimidinyl)-propylidene] bisphosphonic acid, tetraethyl ester) with aspirin (ASA) and flurbiprofen (FLUR) and cold (4°C) in rat was performed as in the procedure for Table 1 and the results are shown in Table 4.

Claims

What is Claimed:

1. The use of a bisphosphonate ester for the manufacture of a medicament for treating gastric diseases characterized by irritation, ulceration and acid hypersecretion.

2. The use of Claim 1 wherein said bisphosphonate ester is administered intravenously, intramuscularly, topically, transdermally, bucally, orally or parenterally.

3. The use of Claim 1 where the bisphosphonate ester or a pharmaceutically acceptable acid salt thereof is administered in an amount of from about 0.001 mg to about 1.0 grams per dose.

4. The use of Claim 1 where the bisphosphonate ester is:

a) (2-((4-(2-fluoro-6-nitrophenoxy)-6-methyl-2- pyrimidinyl)arnino)ethylidene)bis(2,2'-(5,5-dimethyl-2,2' dioxide-1,3,2- dioxaphosphorphinane));

b) (2-((4-(2,4-difluorophenoxy)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'- (5,5-dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

c) (2-((4-(2-,4-dibromophenoxy)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'- (5,5-dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

d) (2-((4-(4-cyanophenoxy)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5- dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

e) (2-((4-phenoxy-6-methyl- 2-pyrimidinyl)amino)ethylidene)bisphosphonic acid tetraethyl ester;

f) (2-((4-(3,4-dichlorophenoxy)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'- (5,5-dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

g) (2-((4-(3-chlorophenoxy)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5- dimethyl-2,2' dioxide-1 ,3,2-dioxaphosphorphinane));

h) (2((4-(methyl)-6-methoxy-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5- dimethyl-2,2'-dioxide-1,3,2-dioxaphosphorphine));

i) (2-((4-(4-morpholinyl)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5- dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

j) (2-((4-(4-piperidinyl)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5- dimethyl-2,2' dioxide-1 ,3,2-dioxaphosphorphinane));

k) (2-((4-(phenylthio)-6-methyl-2-pyrimidinyl)amino)ethylidene)bis(2,2'-(5,5- dimethyl-2,2' dioxide-1,3,2-dioxaphosphorphinane));

l) (4-oxo-3,4-diphenylbutylidene)bis-, tetraethyl ester phosphonic acid; m) [5-(3-fluorobenzoyl)-2,4-dihydro-3H-pyrazol-3-ylidene]bis-, tetraethyl ester phosphonic acid;

n) [4-(3-fluorophenyl)-4-oxobutylidene]bis-, tetraethyl ester phosphonic acid; o) (4-oxo-4-phenylbutylidene)bis-, tetraethyl ester phosphonic acid;

p) (3-(3-Cyano-2,5-dimethyl-pyrazolo(1,5-a)pyrimidin-7-yl)- propylidene)bisphosphonic acid tetraethyl ester;

q) (dichloromethylene)bis-, phosphonic acid disodium salt; or

r) [3-(1,6-Dihydro-1-methyl-6-oxo-4-phenyl-2-pyrimidinyl)-propylidene] bisphosphonic acid, tetraethyl ester.

5. The use of Claim 1 wherein the bisphosphonate ester is:

a) (4-oxo-3,4-diphenylbutylidene)bis-, tetraethyl ester phosphonic acid; b) [5-(3-fluorobenzoyl)-2,4-dihydro-3H-pyrazol-3-ylidene]bis-, tetraethyl ester phosphonic acid;

c) [4-(3-fluorophenyl)-4-oxobutylidene]bis-, tetraethyl ester phosphonic acid; d) (4-oxo-4-phenylbutylidene)bis-, tetraethyl ester phosphonic acid;

e) (3-(3-Cyano-2,5-dimethyl-pyrazolo(1,5-a)pyrimidin-7-yl)- propylidene)bisphosphonic acid tetraethyl ester;

f) (dichloromethylene)bis-, phosphonic acid disodium salt; or

g) [3-(1,6-Dihydro-1-methyl-6-oxo-4-phenyl-2-pyrimidinyl)-propylidene] bisphosphonic acid, tetraethyl ester.