WO2006083687A1

WO2006083687A1 - Crystal salt of xanthine oxidase inhibitors

Info

Publication number: WO2006083687A1
Application number: PCT/US2006/002833
Authority: WO
Inventors: Bertrand M.C. Plouvier; Lewis Siu Leung Choi
Original assignee: Cardiome Pharma Corp; WAGNER EMILY W
Current assignee: Cardiome Pharma Corp; WAGNER EMILY W
Priority date: 2005-01-28
Filing date: 2006-01-26
Publication date: 2006-08-10
Anticipated expiration: 2007-07-28

Abstract

The invention provides choline salts of oxypurinol, processes for the preparation of such salts, pharmaceutical compositions incorporating such salts, and methods for the treatment of conditions and/or diseases using the salts and compositions.

Description

CRYSTAL SALT OF XANTHINE OXIDASE INHIBITORS

FIELD OF THE INVENTION

The invention relates to crystal salts of oxypurinol, processes for the preparation of such crystal salts, pharmaceutical compositions incorporating such salts, and methods for the treatment of diseases and conditions using these salts and compositions.

BACKGROUND OF THE INVENTION

Allopurinol and oxypurinol, inhibitors of the enzyme xanthine oxidase, which converts hypoxanthine to xanthine, and xanthine to uric acid, have been indicated for the treatment of a variety of conditions. These compounds have been used in the treatment of gout and hyperuricaemia (US Patent No. 5,484,605), and are also indicated for suppressing the harmful effects of oxygen radicals that mediate ischaemia-reperfusion injury in a variety of tissues including the heart, lung, kidney, gastrointestinal tract, and brain, and in inflammatory joint diseases such as rheumatoid arthritis. (See for example, US. Patent No.6,004,966. In addition, these compounds have also been reported to be useful in treating excessive resoiption of bone. (US Patent No. 5,674,887), and for the effective treatment of congestive heart failure (US Patent No. 6,569,862).

Allopurinol and oxypurinol are poorly resorbed, and there have been a number of foπnulations developed for treatment of gout and chronic inflammatory intestinal diseases to address this problem. These formulations include oral dosage forms of oxypurinol alkali or alkaline earth salts, in an amorphous or crystalline, non-micronized state; and oxypurinol or its alkali or alkaline earth salts in the form of a solids dispersion with pharmacologically inert adjuvants in a specified ratio (U.S. Patent Nos. 5,661,154 and 5,368,864).

The citation of any reference herein is not an admission that such reference is available as prior art to the instant invention. SUMMARY OF THE INVENTION

Applicants were able to obtain stable, purified, crystalline choline salts of oxypurinol, and determine their structure by X-ray crystallographic analysis. Accordingly, the present invention relates to a stable crystalline form of a choline salt of oxypurinol.

The crystalline oxypurinol choline salts of the invention have both in vitro and in vivo biological activity. The crystralline choline salts of oxypurinol have enhanced solubility and stability properties as compared to the oxypurinol free acid, and have properties which may enable faster dissolution and targeting than the oxypurinol free acid. Therefore, salts of the present invention provide improved pharmaceutical compositions.

In an aspect of the invention a crystalline oxypurinol choline salt is provided that extends the stability and solubility of oxypurinol compared to oxypurinol free acid.

Another aspect of the invention provides a crystalline oxypurinol choline salt in the form of crystals free from waters of crystallization. Crystals of the invention may be substantially non-hygroscopic or slightly hygroscopic.

A further aspect of the invention resides in obtaining certain choline salts of oxypurinol in sufficient quality to determine the three dimensional (tertiary) structure of the compound by X-ray diffraction methods. Accordingly, the invention provides crystals of sufficient quality to obtain a determination of the three-dimensional structure of a choline salt of oxypurinol to high resolution. In particular, crystals of the invention are Diffraction Quality Crystals.

In a still further aspect, the invention relates to a stable crystalline choline salt of oxypurinol comprising molecules of oxypurinol choline exhibiting hydrogen bond interactions in the unit cell. In an embodiment, the crystalline choline salt comprises 8 molecules of oxypurinol choline salts in a unit cell.

The oxypurinol choline salt crystals claimed in the context of certain aspects of the invention have high purity or are substantially pure. In one aspect, the oxypurinol choline salts have a purity of at least 95%, in particular a purity of at least 98%, more particularly greater than 99%, most particularly greater than 99.5%. The invention relates to a process for preparing a crystalline oxypurinol choline salt by reacting oxypurinol free acid with a choline compound, and to a crystalline oxypurinol choline salt obtainable by this process.

The invention also relates to the use of crystalline oxypurinol choline salt for producing drags, in particular pharmaceutical compositions for combating a condition and/or disease discussed herein. Thus, a choline salt of oxypurinol of the invention may be used to prepare pharmaceutical compositions. In an aspect, the invention provides a method for preparing a pharmaceutical composition comprising mixing a choline salt of oxypurinol, preferably a crystalline choline salt of oxypurinol, into a selected pharmaceutical vehicle, excipient or diluent, and optionally adding other therapeutic agents.

The invention contemplates a composition, in particular a pharmaceutical composition, comprising an oxypurinol choline salt of the invention. In a particular embodiment of the invention, a solid form pharmaceutical composition is provided (e.g., tablets, capsules, or a powdered or pulverized form) comprising a crystalline oxypurinol choline salt.

In particular, the present invention contemplates crystalline forms of oxypurinol as a choline salt, which can be processed galenically as stable, well-defined solid substances. Such crystalline forms allow for prolonged stability in storage and for oral and intravenous administration of the drug. Therefore, the invention provides a crystalline form of oxypurinol as a choline salt as a solid formulation. A solid formulation may be in the form of a powder (e.g., a sterile packaged powder, capsule (soft and hard capsules), sachet, tablet, pill, buccal, or lozenge).

The invention further contemplates a method for preventing and/or treating a condition and/or disease discussed herein in a subject comprising administering an effective amount of an oxypurinol choline salt of the invention. The invention also relates to the use of an oxypurinol choline salt of the invention in the preparation of a medicament for preventing and/or treating a condition and/or disease discussed herein.

The knowledge obtained concerning the choline salts of oxypurinol may be used to model the tertiary structure of the compounds and related compounds i.e. analogs and derivatives of oxypurinol and salts thereof. Thus, the invention provides compounds having substantially the same three-dimensional structure of an oxypurinol choline salt of the invention. In addition, the knowledge of the structure of the choline salts of oxypurinol provides a means of investigating the mechanism of action of these compounds in the body. For example, the ability of compounds to inhibit xanthine oxidase activity may be predicted by various computer models. The knowledge of the atomic coordinates and atomic details of the choline salts of oxypurinol may be used to design, evaluate computationally, synthesize and use modulators of oxypurinol and analogues and derivatives thereof, that prevent or treat any undesirable physical and pharmacological properties of oxypurinol. Accordingly, another aspect of the invention is to provide material which is a starting material in the rational design of drugs which mimic the action of oxypurinol compounds. These drugs may be used as therapies that are beneficial in the prevention and/or treatment of conditions and/or diseases discussed herein.

These and other aspects of the present invention will become evident upon reference to the following detailed description and attached drawings. In addition, reference is made herein to various publications, which are hereby incorporated by reference in their entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in relation to the drawings in which:

Figure 1 shows the ORTEP molecular representations of molecules of oxypurinol choline salt obtained from the two batches of the oxypurinol choline salt obtained from the crystallization process set forth in Preparation Method 1.

Figure 2 shows some resonance forms for oxypurinol.

Figures 3-5 show the powder X-ray diffraction patterns of the two batches of oxypurinol choline salt obtained from Preparation Method 1 and the batch of oxypurinol choline salt obtained from Preparation Method 2.

Figures 6-8 show comparisons between the powder X-ray diffraction patterns of the two batches of oxypurinol choline salt obtained from Preparation Method 1 and the batch of oxypurinol choline salt obtained from Preparation Method 2. Figure 9 shows the simulated powder diffraction pattern generated from the single crystal structure solution of the first batch of oxypurinol choline salt obtained from Preparation Method 1.

Figure 10 shows a molecular representation (ORTEP) of a molecule of an oxypurinol choline salt with 50 % probability thermal ellipsoids shown; selected H-atoms are shown with the other H-atoms omitted for clarity.

Figure 11 is a representation of the hydrogen bonding in the solid state of an oxypurinol choline salt.

DETAILED DESCRIPTION OF THE INVENTION

Glossary

The general definitions used herein have the following meanings within the scope of the present invention.

It is to be understood that the recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range (e.g., 1 to 5 includes 1 , 1.5, 2, 2.75, 3, 3.90, 4, and 5). It is also to be understood that all numbers and fractions thereof are presumed to be modified by the term "about." The term "about" means plus or minus 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% of the number to which reference is being made. Further, it is to be understood that "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a formulation containing "an oxypurinol choline salt" includes two or more such inhibitors.

"Oxypurinol" refers to a compound of the Formula I

I wherein R¹ is hydrogen or lower alkyl, and R² is hydrogen, hydroxyl or lower alkyl. "Lower alkyl" refers to a branched or linear hydrocarbon radical, typically containing from 1 through 10 carbon atoms, more preferably 1 to 6 carbon atoms. Typical alkyl groups include but are not limited to methyl, ethyl, 1 -propyl, 2-propyl, 1 -butyl, 2-butyl, tert-butyl, pentyl, hexyl, and the like.

The term "oxypurinol" in particular refers to (4,6-dihydroxypyrazole[3,4- djpyrimidine], functional derivatives, or tautomeric forms thereof. Tautomeric forms of oxypurinol are shown in Table 20.

A "functional derivative" of oxypurinol refers to a compound that possesses a biological activity (either functional or structural) that is substantially similar to the biological activity of oxypurinol. The term "functional derivative" is intended to include "variants" "analogs" or "chemical derivatives" of oxypurinol. The term "variant" is meant to refer to a molecule substantially similar in structure and function to oxypurinol or a part thereof. A molecule is "substantially similar" to oxypurinol if both molecules have substantially similar structures or if both molecules possess similar biological activity. The term "analog" refers to a molecule substantially similar in function to an oxypurinol molecule. The term "chemical derivative" describes a molecule that contains additional chemical moieties which are not normally a part of the base molecule. .

The term "substantially pure" or "high purity" includes a purity of at least 95%, and preferably at least 97% by weight (e.g., at least 99% to 99.5% by weight). Impurities include by-products of synthesis or degradation.

"Therapeutically effective amount" relates to a dose of an active ingredient (i.e. oxypurinol) that will lead to the desired pharmacological and/or therapeutic effect. The desired pharmacological effect is, to alleviate a condition or disease described herein, or symptoms associated therewith. A therapeutically effective amount of a substance may vary according to factors such as the disease state, age, sex, and weight of the individual, and the ability of the substance to elicit a desired response in the individual. Dosage regima may be adjusted to provide the optimum therapeutic response. For example, several divided doses may be administered daily or the dose may be proportionally reduced as indicated by the exigencies of the therapeutic situation. A therapeutically effective amount may be estimated from cell culture assays or animal cell models. A dose maybe formulated in animal models to achieve a circulating concentration range of compound that includes an effective concentration as initially determined in a cell culture. This information may be used to more accurately determine useful doses in humans. A therapeutically effective dose can also be estimated from pharmacokinetic data. For example, a dose that has an area under the blood concentration-time curve (AUC) within about 50%, 60%, 70%, 80% or 90% or more of the AUC of a dose known to be effective for the indication being treated is expected to be effective.

The terms "subject", "individual" and "patient" refer to an animal including a warmblooded animal such as a mammal, which is afflicted with or suspected of having or being predisposed to a condition and/or disease as discussed herein. In particular, the terms refer to a human. The terms also include but are not limited to domestic animals bred for food, sports, or as pets, including horses, cows, sheep, poultry, fish, pigs, cats, dogs, and zoo animals.

The methods herein for use on subjects contemplate prophylactic as well as therapeutic or curative use. Typical subjects for treatment include persons susceptible to, suffering from or that have suffered a condition and/or disease described herein. In particular, suitable subjects for treatment in accordance with the invention include persons that are susceptible to, suffering from or that have suffered heart failure, particularly congestive heart failure or acute cardiogenic shock. In particular aspects of the invention patients are selected where an increase in myocardial contractility with reduced energy requirements is desirable. More particularly, patients are selected where increased cardiac efficiency is desirable.

The term "pharmaceutically acceptable vehicle, excipient, or carrier" includes a medium which does not interfere with the effectiveness or activity of an active ingredient and which is not toxic to the hosts to which it is administered. Excipients include diluents, binders, adhesives, lubricants, disintegrates, bulking agents, and miscellaneous materials such as absorbants, that may be needed in order to prepare a particular formulation.

The terms "preventing and/or treating" and "prophylactic and/or therapeutic" refer to administration to a subject of biologically active ingredients either before or after onset of a condition or disease. If the agent is administered prior to exposure to a factor causing a condition or disease the treatment is preventive or prophylactic (i.e., protects the host against damage). If the agent is administered after exposure to the factor causing a condition or disease the treatment is therapeutic (i.e., alleviates the existing damage). A treatment may be either performed in an acute or chronic way.

A "condition and/or disease" contemplated herein refers to an indication that requires modulation of xanthine oxidase or which utilizes xanthine oxidase inhibitors for treatment, intervention, or prevention. In particular applications the condition and/or disease is a cardiovascular disease and related diseases, ischaemia-reperfusion injury in tissues including the heart, lung, kidney, gastrointestinal tract, and brain, diabetes, inflammatory joint diseases such as rheumatoid arthritis, respiratory distress syndrome, kidney disease, liver disease, sickle cell disease, sepsis, burns, viral infections, hemorrhagic shock, gout, hyperuricaemia, and conditions associated with excessive resorption of bone.

Cardiovascular and related diseases include, for example, hypertension, hypertrophy, congestive heart failure, heart failure subsequent to myocardial infarction, arrhythmia, myocardial ischemia, myocardial infarction, conditions associated with poor cardiac contractility, conditions associated with poor cardiac efficiency, ischemia reperfusion injury, and diseases that arise from thrombotic and prothrombotic states in which the coagulation cascade is activated.

In particular embodiments of the invention the condition or disease is congestive heart failure. Heart failure may arise from any disease that affects the heart and interferes with the circulation. By way of example, a disease that increases the workload of the heart muscle, such as hypertension, may eventually weaken the force of the contractions of the heart. The methods, compositions and formulations of the invention are suitable for the treatment of congestive heart failure of idiopathic, ischemic, or other causes.

"Diffraction Quality Crystal" refers to a crystal that is well-ordered and of a sufficient size, i.e., at least 10 μm, at least 50 μm, or at least 100 μm in its smallest dimension such that it produces measurable diffraction to at least 3 A resolution, preferably to at least 2 A resolution, and most preferably to at least 1.5 A resolution or lower. Diffraction quality crystals include native crystals, heavy-atom derivative crystals, and co-crystals.

"Unit Cell" refers to the smallest and simplest volume element (i.e., parallelepiped- shaped block) of a crystal that is completely representative of the unit or pattern of the crystal, such that the entire crystal may be generated by translation of the unit cell. The dimensions of the unit cell are defined by six numbers: dimensions a, b and c and the angles are defined as α, β, and γ (Blundell et al., Protein Crystallography, 83-84, Academic Press. 1976). A crystal is an efficiently packed array of many unit cells.

"Monoclinic" unit cell refers to a unit cell in which a Jb ≠,; α=γ=90°; and β>90°.

"Space Group" refers to the set of symmetry operations of a unit cell. In a space group designation (e.g., C2) the capital letter indicates the lattice type and the other symbols represent symmetry operations that may be carried out on the unit cell without changing its appearance.

"Structure coordinates" refers to mathematical coordinates derived from mathematical equations related to the patterns obtained on diffraction of a monochromatic beam of X-rays by the atoms (scattering centers) of an oxypurinol choline salt in crystal form. The diffraction data are used to calculate an electron density map of the repeating unit of the crystal. The electron density maps are used to establish the positions of the individual atoms within the unit cell of the crystal. Structural coordinates can be slightly modified and still render nearly identical three dimensional structures. A measure of a unique set of structural coordinates is the root- mean-square deviation of the resulting structure. Structural coordinates that render three dimensional structures that deviate from one another by a root-mean-square deviation of less than 2 A, preferably less than 0.5 A, more preferably less than 0.3 A, may be viewed by a person of ordinary skill in the art as identical.

Variations in structural coordinates may be generated because of mathematical manipulations of the structural coordinates of an oxypurinol choline salt described herein. For example, the structural coordinates of Table 5 or Table 14 may be manipulated by crystallographic permutations of the structural coordinates, fractionalization of the structural coordinates, integer additions or substractions to sets of the structural coordinates, inversion of the structural coordinates or any combination of the above. Variations in structure resulting from changes in any of the components that make up a structure of the invention may also account for modifications in structural coordinates. If such modifications are within an acceptable standard error as compared to the original structural coordinates, the resulting structure may be the same.

"Having substantially the same three-dimensional structure" refers to a compound that is characterized by a set of molecular structure coordinates that have a root mean square deviation (r.m.s.d.) of up to about or equal to 1.5 A, preferably 1.25 A, preferably 1 A, and preferably 0.5 A, and preferably 0.25 A, when superimposed onto the molecular structure coordinates of Table 5 or Table 14 when at least 50% to 100% of the coordinates are included in the superposition. The program MOE may be used to compare two structures (Chemical Computing Group, Inc., Montreal, Canada).

Oxypurinol Choline Salts of the Invention

The present invention provides stable choline salts of oxypurinol. A choline salt of oxypurinol may be represented by the following structure:

A choline salt of oxypurinol of the invention may have greater solubility than oxypurinol free acid. In particular, a choline salt of oxypurinol may have a solubility in water or alcohol that is 2, 3, 4, or 5 fold greater than the oxypurinol free acid. In embodiments of the invention, the solubility of a crystalline choline salt of oxypurinol is about 130- 160 mg/mL, in particular 140-155 mg/mL, more particularly 150-155 mg/mL.

A choline salt of oxypurinol of the invention may have long-term stability to UV light, oxidation, heat and humidity. In particular a choline salt of oxypurinol may have greater thermal stability than oxypurinol free acid. In particular, a crystalline choline salt of oxypurinol may be more stable than oxypurinol free acid when exposed to atmospheric oxygen or nitrogen at about 15-30⁰C for about 3-80 days. Oxypurinol choline salts of the invention may have a particle size in the range from 10 to 2000 μm, preferably from 50 to 1000 μm, particularly preferably from 100 to 800 μm, very particularly preferably in the range from 100 to 600 μm. For determining the size distribution of oxypurinol choline salt crystals, both sieve analysis and laser diffraction spectrometry are suitable.

A crystalline choline salt of oxypurinol may comprise molecules of oxypurinol choline in a unit cell held together by hydrogen bond interactions. In particular, the crystalline choline salt comprises 8 molecules of oxypurinol choline in a unit cell.

In an aspect, a crystalline oxypurinol choline salt is provided which comprises molecules of oxypurinol choline salt in a unit cell held together by hydrogen bond interactions from the deprotonated pyrimidine nitrogen atom of a molecule of oxypurinol to the quaternary ammonium of choline. In an embodiment, the distances between the nitrogen and quarternary ammonium is about 3-5 A, in particular 4 A.

The ratio of oxypurinol and choline in a crystalline oxypurinol choline salt of the invention may be 1:2, in particular 1:1.

A crystal of the invention may take any crystal symmetry form based on the type of choline salt molecule, the hydrogen bond interactions, and/or the space group. In an embodiment of the invention, a crystalline oxypurinol choline salt has space group symmetry C2/c. In another embodiment of the invention, the crystal of oxypurinol choline salt comprises monoclinic unit cells. A unit cell for a crystal of a oxypurinol choline salt of the invention may have the dimensions a = 14.78 ± 0.01, b= 11.24 ± 0.01, c = 14.70± 0.01 or a = 14.82 ± 0.01, b= 11.22 ± 0.01, c = 14.72 ± 0.01. A unit cell for a crystal of an oxypurinol choline salt of the invention may have the following angles: α = 90.0°, β = 92.5°, and γ = 90.0°.

An oxypurinol choline salt of the invention may be further characterized by having one or more of the following properties: a) at least 1, 5, 10, 15, or 18 of the atomic coordinates as shown in Table 5 or Table 14; b) at least 1, 5, 10, 15, 20, 30, 40, 50, 60, 70-, 80, 90, or 95 of the bond lengths and angles as shown in Table 6 or Table 15; c) at least 1 , 5, 10, 15, or 18 of the anisotropic displacement parameters as shown in Table 7 or Table 16; d) at least 1, 5, 10, 15, or 17 of the hydrogen coordinates and isotropic displacement parameters as shown in Table 8 or Table 17; e) at least 1, 5, 10, 15, 20, 25 of the torsion angles as shown in Table 9 or Table 18; f) at least 1, 2, or 3 of the hydrogen bonds as shown in Table 10 or Table 19; g) a melting point of about 160⁰C to 175°C, in particular 163⁰C to 174°C, more particularly 164°C to 173⁰C, most particularly 173⁰C; h) a solubility in water of about 130-150 mg/mL, in particular 140-155 mg/mL; and i) a crystal dimension of about 0.20 x 0.12 x 0.07 mm or about 0.30 x 0.15 x 0.10 mm.

In an aspect of the invention a crystalline choline salt of oxypurinol is characterized by (a); (a) and (b); (a), (b) and (c); (a), (b), (c), and (d); (a) through (e); (a) through (f); (a) through (g); (a) through (h); (a) through (i); (a), (g) and (h); (a) and (h); and (a) (b), (g) and (h).

Three-dimensional structural representations of a choline salt of oxypurinol expressed using the x, y, and z, coordinates are shown in Figure 1 and in Figure 10. Hydrogen bonding of a crystalline choline salt of oxypurinol is shown in Figure 11.

Preparation of Oxypurinol Salts of the Invention

A crystalline salt of the invention may be prepared by treating oxypurinol free acid with a choline compound, and purifying the salt by crystallization. A stable and/or substantially pure crystalline choline salt may be formed as described in the Examples.

In an aspect the invention relates to a process for preparing crystalline oxypurinol choline salt by reacting oxypurinol free acid with choline hydroxide. The process may be carried out in water, a water-miscible organic solvent, or in a mixture of water and a water- miscible organic solvent. The proportion of water in a solvent may be about 0 to 50% by weight, in particular from about 0 to 10% by weight. A water-miscible solvent maybe selected that is water-miscible, thermally stable, or a volatile solvent containing only carbon, hydrogen and oxygen, such as alcohols, ethers, esters, ketones and acetals. Examples of solvents are methanol, ethanol, π-propanol, isopropanol, l-methoxy-2-butanol, l-propoxy-2-propanol, tetrahydrofuran or acetone is used.

The molar ratio of the reaction substrates oxypurinol free acid and choline hydroxide in the process is in the range 1:3, 1:2, 1:1.5, 1:1, 1:0.95 or 1:0.9 or any ratio in between the ranges indicated above.

In preparing the compounds of the invention, conventional protecting groups may be used to block reactive groups. Appropriate blocking and deblocking schemes are known to the skilled artisan (See T. W. Greene and P. G. M. Wuts, 2.sup.nd ed., Protective Groups in Organic Synthesis, John Wiley & Sons, New York, 1991). In general, particular protective groups are selected which adequately protect the reactive groups in question during subsequent synthetic steps and which are readily removable under conditions which will not cause degradation of the desired product. In vivo, some protecting groups are cleaved or metabolically converted into the active functional group (e.g., via hydrolysis or oxidation). Metabolically cleaved protecting groups are preferred, in some cases. Examples of protecting groups that may be used include hydroxyl protecting groups such as methyl ethers including methoxymethyl, methylthiomethyl, and t-butylthiomethyl.

The invention also encompasses compounds identical to the oxypurinol salts of the invention except that one or more conventional protecting groups are used, such as the hydroxyl protecting groups described herein.

A crystalline oxypurinol choline salt may be formed by, for example, dissolving oxypurinol choline salt in a solvent as discussed above, and evaporating the solvent. The crystals may also be prepared by diffusion using standard methods.

It will also be appreciated that crystalline choline salts of functional derivatives of oxypurinol may be prepared using the methods described herein, and the salts of such derivatives prepared by the methods are contemplated in the present invention. Modeling and Screening Applications

A crystal of a choline salt of oxypurinol may be used to model the three dimensional structure of the salts and related compounds i.e., analogs and derivatives of oxypurinol and salts thereof. Therefore, the invention provides a method for determining the three-dimensional structure of an oxypurinol choline salt crystal, comprising the steps of providing a crystal of the present invention; and analyzing the crystal by x-ray diffraction to determine the three- dimensional structure. In an aspect, the invention provides for the production of three- dimensional structural information (or "data") from the crystals of the invention. Such information may be in the form of structural coordinates that define the three-dimensional structure of an oxypurinol choline salt in a crystal or a portion thereof (see Table 5 and Table 14). An example of a portion of an oxypurinol choline salt includes the site that interacts with a xanthine oxidase. The information on structural coordinates may include other structural information, such as vector representations of the molecular structures coordinates.

The invention provides methods of producing a computer readable database comprising the three-dimensional molecular structural coordinates of an oxypurinol choline salt. The methods may comprise obtaining three-dimensional structural coordinates defining an oxypurinol choline salt or portion thereof from a crystal of the salt (see Table 5 and Table 14); and introducing the structural coordinates into a computer to produce a database containing the molecular structural coordinates of an oxypurinol choline salt. The invention also contemplates databases produced by such methods.

The invention also provides computer machine-readable media embedded with the three-dimensional structural information obtained from the oxypurinol choline crystals of the invention, or portions thereof. The types of machine- or computer-readable media into which the structural information is embedded include without limitation magnetic tape, floppy discs, hard disc storage media, optical discs, CD-ROM, electrical storage media such as RAM or ROM, and hybrids of any of these storage media. Machine-readable media of the invention may also comprise additional information that is useful for representing the three-dimensional structure, including, but not limited to, isotropic displacement parameters.

Various machine-readable media are provided in the present invention. In one aspect, a machine-readable medium is provided that is embedded with information defining a three- dimensional structural representation of any of the crystals of the present invention, or a fragment or portion thereof. The information may be in the form of molecular structure coordinates, such as, for example, those of Table 5 and Table 14.

Molecular structure coordinates and machine-readable media discussed herein have a variety of uses. The coordinates may be used to solve the three-dimensional X-ray diffraction and/or solution structures of other pyrazole xanthine oxidase inhibitors, and unrelated structures, to high resolution. The information may also be used in molecular modeling and computer-based screening applications to, for example, intelligently design modulators (e.g., agonists) of pyrazole xanthine oxidase inhibitors. The modulators may be used directly or as lead compounds in pharmaceutical efforts to identify compounds that modulate xanthine oxidase activity. Compounds that are agonists of oxypurinol or antagonists of xanthine oxidase may be incorporated in pharmaceutical compositions and used to prevent and/or treat a condition and/or disease discussed herein.

Also provided in the present invention is a method for obtaining structural information about a molecule of unknown structure comprising: crystallizing the molecule or molecular complex; generating an x-ray diffraction pattern from the crystallized molecule or molecular complex; and using a molecular replacement method to inteipret the structure of said molecule; wherein said molecular replacement method uses the structure coordinates of Table 5 or Table 14, or structure coordinates having a root mean square deviation for the atoms of the structure coordinates of up to about 2.0 A, preferably up to about 1.75 A, preferably up to about 1.5 A, preferably up to about 1.25 A, preferably up to about 1.0 A, preferably up to about 0.75 A. The coordinates of the resulting structure may be stored in a computer readable database as described herein.

Compositions and Treatment Methods

The invention provides pharmaceutical compositions formulated from an oxypurinol choline salt of the invention (e.g., in particular, a crystalline choline salt of oxypurinol), a combination of the oxypurinol choline salts of the invention, or a combination of oxypurinol and oxypurinol choline salt(s) of the invention. The crystalline salts of the present invention enable the use of a substantially pure or high purity active ingredient in pharmaceutical compositions.

Routes of administration of a composition of the invention include oral, pulmonary, topical, body cavity (e.g., nasal eye, buccal), transdermal, and parenteral (e.g., intravenous, intramuscular, and subcutaneous routes). Externally activated drug delivery systems include those activated by heat, ultrasound, electrical pulse, iontophoresis, electrophoresis, magnetic modulation, and light.

Compositions include solids (tablets, soft or hard gelatin capsules), semi-solids (gels, creams), or liquids (solutions, colloids, or emulsions), preferably solids. Colloidal carrier systems include microcapsules, emulsions, microspheres, multi-lamellar vesicles, nanocapsules, uni-lamellar vesicles, nanoparticles, microemulsions, and low-density lipoproteins. Systems for parenteral administration include lipid emulsions, liposomes, mixed micellar systems, biodegradable fibers, and fibrin-gels, and biodegradable polymers for implantation. Systems for pulmonary administration include metered dose inhalers, powder inhalers, solutions for inhalation, and liposomes. A composition can be formulated for sustained release (multiple unit disintegrating particles or beads, single unit non-disintegrating system), controlled release (oral osmotic pump), and bioadhesives or liposomes. Controlled release compositions include those, which release intermittently, and those that release continuously.

A composition of the invention includes one or more pharmaceutical carriers, and optionally one or more bioactive agents. Pharmaceutical carriers include inorganics such as calcium phosphate and titanium dioxide; carbohydrates such as -lactose monohydrate and - cyclodextrin; surfactants such as sodium lauryl sulfate and poloxamers; polymers such as starch, ethyl cellulose, hydrogels, and polyacrylic acids; lipids such as polylactides, stearic acid, glycerides, and phospholipids; or amino acids and peptides such as leucine and low density lipoprotein.

For example, compositions formulated from a salt of oxypurinol of the invention may include: (a) a tablet including an oxypurinol choline salt of the invention, a pharmaceutical carrier and may also include an absorption enhancer, (b) a capsule containing a crystalline, powder, microspheres, or pellets made from an oxypurinol choline salt of the invention, even though, in the capsule, oxypurinol choline salt is no longer in the form of clear crystals (e.g., prisms), (c) a soft gel capsule made from an oxypurinol choline salt of the invention, (d) an aqueous solution of an oxypurinol choline salt of the invention, wherein the dissolved oxypurinol choline salt is no longer crystalline, and may for example, no longer be associated with either the choline, and (e) other parenteral, transdermal, intranasal or oral administration forms known to those skilled in the art. Oxypurinol derived from a salt of the invention is also useful in certain methods of treatment of the invention. Pure oxypurinol alone (e.g., oxypurinol free acid), however, is not contemplated for use in a composition of the invention.

In certain aspects of the invention the pharmaceutical composition is a solid form composition wherein the active ingredient i.e., salt of the invention is in crystalline form. For example, the composition can be in the form of a tablet, capsule, or powder. A particularly preferred solid form composition of the invention having enhanced solubility and/or stability properties comprises a crystalline choline salt of oxypurinol.

In an embodiment of the invention a composition is provided which is an oral dosage form comprising an oxypurinol choline salt of the invention (preferably the crystalline choline salt) and a non-hygroscopic, inert and preferably anhydrous excipient (e.g., lactose or mannitol). In another embodiment, a composition is provided which is a soft gelatin capsule comprising a oxypurinol salt of the invention (preferably a crystalline choline salt) and at least one hydrophilic vehicle (e.g., glycerin or propylene glycol) and at least one lipophilic vehicle (e.g., PEG 400).

A composition of the invention is typically formulated so that it remains active at physiologic pH. The composition may be formulated in the pH range 4 to 7.

The oxypurinol salts of the invention may be converted into pharmaceutical compositions using customary methods. For example, a crystalline oxypurinol choline salt of the invention may be mixed in with other pharmaceutically acceptable excipients.

A composition or formulation of the invention may be present in a core surrounded by one or more layers including an enteric coating layer. Accordingly, the invention provides an enteric formulation containing a core comprising an oxypurinol choline salt of the invention (preferably the crystalline choline salt), wherein the core is surrounded by one or more layers including an enteric coating layer or enteric envelope. The core may be in the form of a tablet or capsule. A pre-coating layer or insulating layer may be applied on the core before the enteric coating.

In an aspect of the invention, an oxypurinol choline salt of the invention (preferably the crystalline choline salt) may be present in a core surrounded by one or more layers including an enteric coating layer. The oxypurinol choline salt of the invention (preferably the crystalline choline salt) may be mixed with inert, preferably water soluble, conventional pharmaceutically acceptable constituents to obtain the desired concentration of the pyrazole xanthine oxidase inhibitor in the final mixture. The active ingredient is also mixed with a substantially inert, pharmaceutically acceptable substance (or substances) which creates a "micro-pH" around each particle of pyrazole xanthine oxidase inhibitor of not less than pH 7, in particular not less than pH 8, when water is adsorbed to the particles of the mixture or when water is added in small amounts to the mixture. Examples of pharmaceutically acceptable substances include without limitation sodium, potassium, calcium, magnesium, and aluminum salts of phosphoric acid, carbonic acid, citric acid, or other suitable weak inorganic or organic acids; substances typically used in antacid preparations such as aluminum, calcium, and magnesium hydroxides; magnesium oxide or composite substances such as, for example, MgOAl₂O₃ or like compounds; organic pH-buffering substances such as trihydroxy-methylamino-methane or other similar, pharmaceutically acceptable pH-buffering substances. The powder mixture may then be formulated into small beads, i.e., pellets or tablets, by conventional pharmaceutical procedures. The pellets, tablets, or gelatin capsules may then be used as cores for further processing.

The cores containing may be separated from enteric coating polymer(s) by applying a pre-coating or insulating coating. The pre-coating protects the core from degradation and discoloration during the coating process and/or during storage, and also serves as a pH- buffering zone. The pH-buffering properties of a pre-coating layer may be further strengthened by introducing in the layer substances chosen from a group of compounds usually used in antacid formulations discussed above. The pre-coating layer typically comprises of one or more water soluble inert layers, optionally containing pH-buffering substances.

The pre-coating layer(s) can be applied to the cores (e.g., pellets or tablets) by conventional coating procedures in a suitable coating pan or in fluidized bed apparatus using water and/or conventional organic solvents for the coating solution. Suitable material for the pre-coating layer may be selected among pharmaceutically acceptable water soluble, inert compounds or polymers used for film-coating applications including without limitation sugar, polyethylene glycol, polyvinylpyrrolidone, polyvinyl alcohol, hydroxypropyl cellulose, hydroxymethyl cellulose, hydroxypropyl methylcellulose, or similar compounds. The thickness of a pre-coating layer(s) may be determined according to the skilled artisan.

When the core is a tablet, the pre-coating layer may be applied by a dry coating technique. A tablet containing the active ingredient may be compressed, and another layer may be compressed around this layer using a suitable tableting technique machine. The outer, pre- coating layer, typically contains pharmaceutically acceptable, in water soluble or in water, rapidly disintegrating tablet excipients. A pre-coating layer may also include conventional plasticizers, pigments, titanium dioxide talc, and other additives. In gelatine capsule formulation of the invention the gelatin capsule itself can serve as a pre-coating layer.

The enteric coating layer may be applied on to the pre-coated cores by conventional coating techniques. Examples of coating techniques include pan coating or fluidized bed coating using solutions of polymers in water and/or suitable organic solvents, or using latex suspensions of the polymers. Suitable enteric coating polymers include, for example, cellulose acetate phthalate, hydroxypropyl methylcellulose phthalate, polyvinyl acetate phthalate, carboxymethylethylcellulose, copolymerized methacrylic acid/methacrylic acid methyl esters (e.g., Eudragit®L12,5 or Eudragit®L100 available from Rohm Pharma of Darmstadt, Germany), or other similar compounds. The enteric coating may also be applied using water- based polymer dispersions including Aquateric®. (FMC Corporation of Chicago, 111.), Eudragit®Ll 00-55 (Rohm Pharma of Darmstadt, Germany), Coating CE 5142 (BASF of Mount Olive, N.J.). Pharmaceutically acceptable plasticizers may also be included in the enteric coating including cetanol, triacetin, citric acid esters such as, for example, those known under the trade name Citroflex® (Pfizer of New York, N. Y.), phthalic acid esters, dibutyl succinate or similar plasticizers. The enteric coating may also include dispersants such as talc, colorants and pigments.

Formulations described by the above embodiments comprise cores containing at least an oxypurinol choline salt of the invention (preferably the crystalline choline salt) optionally mixed with one or more pharmaceutically acceptable excipients. The organic base is believed to potentially enhance the stability of the formulation. A final dosage form encompassing the embodiments discussed above may be either an enteric coated tablet or capsule, enteric coated pellets, pellets dispensed in hard gelatin capsules, or sachets or pellets formulated into tablets.

It may be desirable to keep the water content of a final dosage form low to provide for long term stability during storage. Accordingly, a final package containing capsules filled with enteric coated pellets preferably also comprises a desiccant, which maintains the water content of the gelatin shell to a desired level.

The compositions of the invention provide a useful means for administering oxypurinol to subjects suffering from a condition and/or disease. A composition of the invention may provide advantageous effects in the treatment of conditions or diseases such as cardiovascular disease and related diseases, ischaemia-reperfusion injury in tissues including the heart, lung, kidney, gastrointestinal tract, and brain, diabetes, inflammatory joint diseases such as rheumatoid arthritis, respiratory distress, kidney disease, liver disease, sickle cell disease, sepsis, burns, viral infections, hemorrhagic shock, gout, hyperuricaemia, and conditions associated with excessive resorption of bone, hi particular applications the condition or disease is hypertension, hypertrophy, congestive heart failure subsequent to myocardial infarction, arrhythmia, myocardial ischemia, myocardial infarction, ischemia reperfusion injury, and diseases that arise from thrombotic and prothrombotic states in which the coagulation cascade is activated.

The compositions of the invention can be readily adapted to a therapeutic use in the treatment of cardiovascular and related diseases. Thus, the invention contemplates the use of a composition of the invention for preventing, and/or ameliorating disease severity, disease symptoms, and/or periodicity of recurrence of a cardiovascular or related disease. The invention relates to the use of a crystalline salt of the invention in the preparation of a medicament, in particular a medicament for the prevention or treatment of a condition and/or disease. In an embodiment the condition or disease is a cardiovascular or related disease.

Compositions and methods of the invention utilize therapeutically effective amounts of a choline salt of oxypurinol. The particular amounts of the active substance will vary according to various factors as discussed herein, and ultimately will be decided by the attending physician or veterinarian. Conventional dosage determination tests can be used to ascertain the optimal administration rates for a given protocol of administration. Doses utilized in prior clinical applications for xanthine oxidase inhibitors will provide guidelines for preferred dosage amounts for the methods of the present invention.

In an aspect of the invention, a composition may contain from about 0.1 to 90% by weight (such as about 0.1 to 20% or about 0.5 to 10%) of the active ingredient. In other aspects the content of crystalline oxypurinol choline salt in a composition maybe in the range from 1 to 750 mg, preferably from 2 to 450 mg, particularly preferably from 5 to 225 mg, very particularly preferably in the range from 10 to 150 mg. In tablets where only oxypurinol choline salt is present, the oxypurinol choline salt content can be in the range from 50 to 1500 mg.

A composition of the invention used for prophylactic and therapeutic administration may be sterile. Sterility can be accomplished by filtration through sterile filtration membranes, for example 0.2 micron membranes. Compositions of the invention for prophylactic and therapeutic administration may be stored in unit or multi-dose containers. Dosaging may also be arranged in a subject specific manner to provide a predetermined concentration of xanthine oxidase inhibition activity in the blood.

The methods and compositions of the invention are indicated as therapies or therapeutic agents either alone or in conjunction with other therapeutic agents or other forms of treatment. For example, the compositions may be used in combination with other drugs used to treat cardiovascular diseases including inhibitors of angiotension-converting enzyme (ACE), inotropics, diuretics, and beta blockers. The compositions of the invention may be administered concurrently, separately, or sequentially with other therapeutic agents or therapies.

The inventive crystalline oxypurinol choline salt, its preparation process and its use will be described in more detail with reference to the example below.

EXAMPLES

A choline salt of oxypurinol was prepared, characterized using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) and the solubility compared to that of oxypurinol free acid.

Preparation

Preparation Method 1

Oxypurinol was purchased from DSM (lot # C) and choline hydroxide, 50 wt. % solution in water was purchased from Aldrich (Cat. # 292257, lot # 15727BA).

A choline salt of oxypurinol was prepared from oxypurinol free acid and choline hydroxide as depicted in Scheme 1 :

Scheme 1

To a stirred and refluxing suspension of oxypurinol (8.02 g, 52.7 mmol) in water (1 OO mL) was added a solution of choline hydroxide in water (50 wt. %, 12.5 mL, 52.7 mmol). A homogeneous solution was obtained upon completion of the addition. The solvent was then removed in vacuo to afford the crude choline salt of oxypurinol. Recrystallization from anhydrous ethanol (150 mL) gave brownish crystals which were collected, washed successively with cold anhydrous ethanol and diethyl ether to afford oxypurinol choline salt as a dark orange crystalline solid once grounded with a pestle in a mortar (9.0 g, 70 % yield), mp 165-167 ⁰C; ¹H-NMR (DMSOd₆): δ 3.14 (9H, s, CH₃), 3.46 (2H, t, CH₂), 3.88 (2H, br s, CH₂), 7.53 (IH, s, Ar), 9.40 (3H, br s, OH); MS (ESI^", CH₃OH): m/z 150.9; MS (ESI⁺, CH₃OH): m/z 103.6. A second batch was prepared using the same procedure to prepare an oxypurinol choline salt as a light orange fine crystalline solid with dark orange larger crystals after grinding. (8.65 g, 64 % yield), mp 164-166 ⁰C; ¹H-NMR (DMSO-d₆): δ 3.11 (9H, s, CH₃), 3.42 (2H, t, CH₂), 3.85 (2H, br s, CH₂), 7.48 (IH, s, Ar), 9.25 (3H, br s, OH); MS (ESI^", CH₃OH): m/z 150.9; MS (ESI⁺, CH₃OH): m/z 103.9.

Preparation Method 2

Oxypurinol hemihydrate, nominal water content 6.0% w/w, FW = 152.1 (anhydrous form), was purchased from DSM (lot # 2H0585) and choline hydroxide, concentrated aqueous solution at 50% w/w (50.8% as per C of A), FW = 121.2, was purchased from Sigma (Cat. # C-9154, lot # 015K2601).

Equimolar amounts (20.64 mmol) of oxypurinol hemihydrate and choline hydroxide concentrated aqueous solution were weighed into a beaker. Note: choline hydroxide concentrated solution was a viscous, brown colour solution with turbid appearance, which is the cause for the colorized material. Currently, the use of colorless-light tanned choline hydroxide containing a stabilizer, provided oxypurinol choline salt as a white crystalline solid. The mixture of the two components was stirred for approximately 30 min at room temperature (approximately 23 ⁰C). No oxypurinol particles were visible in solution after stirring. The solvent was removed in vacuo. A brown-yellowish paste was obtained and the residue was taken up with EtOH (50 niL) to further remove any residual water by evaporation under reduced pressure at 40 ⁰C. The residue was then recrystallized from boiling EtOH (50 mL). The hot ethanolic solution was allowed to cool down to room temperature to trigger crystallization of the oxypurinol salt. The recrystallized material was collected (no rinse) and dried over phosphorus pentoxide under low vacuum to give 3.94 g (75% yield) of oxypurinol choline salt as an orange solid (flakes), mp 163-166⁰C; ¹H-NMR (DMSO-d₆): δ 3.13 (9H, s, CH₃), 3.44 (2H, t, CH₂), 3.87 (2H, br s, CH₂), 7.50 (IH, s, Ar), 9.00 (3H, br s, OH); MS (ESF, CH₃OH): m/z 151.0; MS (ESI⁺, CH₃OH): m/z 104.0.

Preparation Method 3

Equimolar amounts of oxypurinol hemihydrate and choline hydroxide concentrated aqueous solution are mixed at ambient or other suitable conditions. The solvent is removed by controlled means as exemplified by, but not limited to, spray drying, tray drying, counter current partition/filtration or lyophilization. The resulting solid, either crystalline in nature as a single or multiple polymorphs or amorphous in nature or some mixed ratio of these, may be further purified by selective precipitation or crystallization from aqueous solution using a pharmaceutically acceptable anti-solvent followed by solvent removal as previously described.

Preparation Method 4

Equimolar amounts of oxypurinol hemihydrate and choline hydroxide concentrated aqueous solution are mixed at ambient or other suitable conditions. The solution is spray dried or spray coated onto a pharmaceutically acceptable support as exemplified by, but not limited to, lactose, such that the solvent is removed by controlled means as exemplified by, but not limited to, spray drying, tray drying, or lyophilization. The resulting solid support containing the oxypurinol salt, either crystalline in nature as a single or multiple polymorphs or amorphous in nature or some mixed ratio of these, may be further incorporated into pharmaceutical dosage forms according to methods practiced by those skilled in the art.

Characterization of Oxypurinol Choline Salt

Table 1 summarizes the characterization data for the two batches of oxypurinol choline salt obtained from Preparation Method 1 above, and the batch of oxypurinol choline salt obtained from Preparation Method 2 above.

The material from the two batches obtained from Preparation Method 1 and the batch obtained from Preparation Method 2 had identical melting points of 173 ° C by DSC . Analysis of X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM micrograph,) showed that the material from the two batches obtained from Preparation Method 1 and the batch obtained from Preparation Method 2 was crystalline and identical (see below and Table

1).

Analysis of the two batches obtained from Preparation Method 1 by single crystal X- ray diffraction, revealed the same unit cell, i.e., monoclinic, and the similarity of its dimensions (see below and Table 1). The distance between the deprotonated pyrimidine nitrogen and the quaternary ammonium was 4 A in material from both batches, based on X-ray crystallographic analysis. Figure 1 depicts the ORTEP representations for both batches. The greater acidity of the proton at the pyrimidine nitrogen (N-4) compared to that in N-6 of oxypurinol free acid may be attributed to the greater resonance stabilization of conjugate base form A over B (see Figure 2).

The choline crystalline salts of oxypurinol prepared had an increased solubility (~ 500 mg/mL at room temperature) compared to oxypurinol free acid (~ 0.1 mg/mL at 37°C).

Differential Scanning Calorimetry (DSC)

The material from the two batches obtained from Preparation Method 1 and the batch obtained from Preparation Method 2 had identical melting points of 173° C by DSC. The analysis was carried out using a TA Instruments 2910 Modulated Differential Scanning Calorimeter (DSC) (Mil #A11913). The instrument was calibrated on 2004-09-28 using a heating rate of 10 °C/min and a nitrogen atmosphere of 50 cc/min, with a calibration due date of 2004-12-28. The analysis was performed in nitrogen at atmospheric pressure, flowing at a rate of 50 cc/min. A portion of each sample was accurately weighed and hermetically sealed into aluminum pans for the analysis. The first sample was heated at 10 °C/min from ambient to approximately 300 ⁰C. There were indications of decomposition prior to 250 ⁰C. Accordingly, the second and third samples were heated to approximately 210 ⁰C. X-Rav Powder Diffraction TXRPD)

Analysis of XRPD showed that the two batches of oxypurinol choline salt obtained from Preparation Method 1 and the batch of oxypurinol choline salt obtained from Preparation Method 2 were equivalent in terms of crystalline structure.

Experimental Details

A Bruker D8 Advance powder X-ray diffractometer equipped with a copper target, a graphite monochromator, and a scintillation detector was used. The generator was set to 40 kV and 40 mA. For all three samples, data was collected from 3-70° 2θ using a step of 0.02° and a total counting time of 1.0 sec/step.

The samples were ground with a mortar and pestle and packed into standard sample holders. The samples were rotated during data collection to reduce any undesired effects caused by the preferred orientation of crystallites.

Results and Conclusions

The powder X-ray diffraction patterns of the three samples (Batch 1 - Preparation Method 1 : BC-154-23; Batch 2 - Preparation Method 1 : SW- 169- 14; Preparation Method 2: BP- 179-52) and are given in Figures 3-5, respectively. Figures 6-8 show comparisons between the samples (Figure 6 - overlain; Figure 7 — offset; Figure 8 — offset and expanded). The background noise was removed from all of the diffraction patterns.

All three samples are crystalline. There are no significant differences seen across the patterns and the minor variations seen are likely due to minor differences in XRD sample preparation. The diffraction patterns of the three samples are very similar to the simulated powder diffraction pattern generated from the single crystal structure solution of the first batch obtained from Preparation Method 1 shown in Figure 9.

Single Crystal X-Ray Diffraction Batch 1 - Preparation Method 1

Tables 2-10 summarize the data for the first batch of oxypurinol choline salt obtained from Preparation Method 1.

Data Collection

A pale orange prism crystal of C_1OH₁₇N₅O₃ from the first batch obtained from Preparation Method 1 having approximate dimensions of 0.20 x 0.12 x 0.07 mm was mounted on a glass fiber. All measurements were made on a Rigaku/ADSC diffractometer with graphite monochromated Mo-Ka radiation.

The data were collected at a temperature of -100.0 + 0.1⁰C to a maximum 2Θ value of 55.7°. Data were collected in a series of φ and ω scans in 0.50° oscillations with 23.0 second exposures. The crystal-to-detector distance was 38.24 mm.

Data Reduction

Of the 11573 reflections that were collected, 2720 were unique (Rint - 0.036); equivalent reflections were merged. Data were collected using d*TREK fd*TREK. Area Detector Software. Version 7.11. Molecular Structure Corporation (2001)] and integrated using the CrystalClear fCrystalClear 1.3.5 SP2. Molecular Structure Corporation (2003)] software package. The linear absorption coefficient, μ, for Mo-Ka radiation is 1.05 cm^"1. Data were corrected for absorption effects using a multi-scan technique (CrystalClear), with minimum and maximum transmission coefficients of 0.857 and 0.993, respectively. The data were corrected for Lorentz and polarization effects.

Structure Solution and Refinement

The structure was solved by direct methods [SIR92: Altomare, A., Cascarano, M., Giacovazzo, C, Guagliardi, A. (1994). J. Appl. Cryst, 26, 343]. All hydrogen atoms involved in hydrogen-bonding were located in difference maps, while all other hydrogen atoms were included in calculated positions but not refined. The final cycle of full-matrix least-squares refinement [Least Squares function minimized: Ew(F₀ ² -F_c ²)²] on F² was based on 2720 reflections and 178 variable parameters and converged (largest parameter shift was 0.00 times its esd) with unweighted and weighted agreement factors of:

Rl = Σ ||Fo| - |Fc|| / Σ |Fo| = 0.055

wR2 = [ Σ ( w (Fo² - Fc²)² )/ Σ w(Fo²)²] ^1/2 = 0.117

The standard deviation of an observation of unit weight [Standard deviation of an observation of unit weight: [Σw(F₀ ²-Fc²)²/(N₀-N_v)]^1/2 where: N₀ = number of observations, N_v = number of variables] was 1.11. The weighting scheme was based on counting statistics. The maximum and minimum peaks on the final difference Fourier map corresponded to 0.24 and — 0.24 e"/A³, respectively.

Neutral atom scattering factors were taken from Cromer and Waber [Cromer, D. T. & Waber, J. T.; "International Tables for X-ray Crystallography", Vol. IV, The Kynoch Press, Birmingham, England, Table 2.2 A (1974)]. Anomalous dispersion effects were included in Fcalc [Ibers, J. A. & Hamilton, W. C; Acta Crystallogr., 17, 781 (1964)]; the values for Δf and Δf ' were those of Creagh and McAuley [Creagh, D. C. & McAuley, WJ .; "International Tables for Crystallography", VoI C, (A.J.C. Wilson, ed.), Kluwer Academic Publishers, Boston, Table 4.2.6.8, pages 219-222 (1992)]. The values for the mass attenuation coefficients are those of Creagh and Hubbell [Creagh, D. C. & Hubbell, J.H..; "International Tables for Crystallography", VoI C, (A.J.C. Wilson, ed.), Kluwer Academic Publishers, Boston, Table 4.2.4.3, pages 200-206 (1992)]. All refinements were performed using SHELXL-97 Sheldrick, G. M. SHELXL-97 [Programs for Crystal Structure Analysis (Release 97-2). University of Gδttingen, Germany (1997)].

Batch 2 - Preparation Method 1

Tables 11-19 summarize the data for the second batch of oxypurinol choline salt obtained from Preparation Method 1. Data Collection

A pale orange prism crystal OfC₁₀HnNsO₃ having approximate dimensions of 0.30 x 0.15 x 0.10 mm was mounted on a glass fiber. All measurements were made on a Bruker X8 APEX diffractometer with graphite monochromated Mo-Ka radiation.

The data were collected at a temperature of -100.0 + 0.1⁰C to a maximum 2Θ value of

56.2°. Data were collected in a series of φ and ω scans in 0.50° oscillations with 10.0 second exposures. The crystal-to-detector distance was 38.02 mm.

Data Reduction

Of the 14111 reflections that were collected, 2928 were unique (Rjnt ⁼ 0.036); equivalent reflections were merged. Data were collected and integrated using the Bruker SAINT [SAINT. Version 6.02. Bruker AXS Inc., Madison, Wisconsin, USA. (1999)] software package. The linear absorption coefficient, μ, for Mo-Ka radiation is 1.05 cm^'1. Data were corrected for absorption effects using the multi-scan technique (SADABS [SADABS. Bruker Nonius area detector scaling and absorption correction - V2.05, Bruker AXS Inc., Madison, Wisconsin, USA]), with minimum and maximum transmission coefficients of 0.870 and 0.990, respectively. The data were corrected for Lorentz and polarization effects.

Structure Solution and Refinement

The structure was solved by direct methods [SIR92: Altomare, A., Cascarano, M., Giacovazzo, C, Guagliardi, A. (1994). J. Appl. Cryst., 26, 343]. AU non-hydrogen atoms were refined anisotropically. A comparison with the sample from the first batch obtained from Preparation Method 1 shows that, but for a few minor differences in final residuals, these two samples have exactly the same solid state structure. All N-H and O-H hydrogen atoms were located in difference maps, while all other hydrogen atoms were included in calculated positions but not refined. The final cycle of full-matrix least-squares refinement [Least Squares function minimized:

was based on 2928 reflections and 178 variable parameters and converged (largest parameter shift was 0.00 times its esd) with unweighted and weighted agreement factors of: R1 = Σ ||Fo| - |Fc|| / Σ |Fo| = 0.059

wR2 = [ Σ ( w (Fo² - Fc²)² )/ ∑ w(Fo²)2]1/2 = 0.109

The standard deviation of an observation of unit weight [Standard deviation of an observation of unit weight: [Σw(Fo²-Fc²)²/(No-Nv)]^1/2 where: N_o = number of observations, N_v = number of variables] was 1.09. The weighting scheme was based on counting statistics. The maximum and minimum peaks on the final difference Fourier map corresponded to 0.27 and -

0.21 e7A³, respectively.

Neutral atom scattering factors were taken from Cromer and Waber [Cromer, D. T. & Waber, J. T.; "International Tables for X-ray Crystallography", Vol. IV, The Kynoch Press, Birmingham, England, Table 2.2 A (1974)]. Anomalous dispersion effects were included in Fcalc [Ibers, J. A. & Hamilton, W. C; Acta Crystallogr., 17, 781 (1964)]; the values for Δf and Δf" were those of Creagh and McAuley [Creagh, D. C. & McAuley, WJ .; "International Tables for Crystallography", VoI C, (A.J.C. Wilson, ed.), Kluwer Academic Publishers, Boston, Table 4.2.6.8, pages 219-222 (1992)]. The values for the mass attenuation coefficients are those of Creagh and Hubbell [Creagh, D. C. & Hubbell, J.H..; "International Tables for Crystallography", VoI C, (A.J.C. Wilson, ed.), Kluwer Academic Publishers, Boston, Table 4.2.4.3, pages 200-206 (1992)]. All refinements were performed using SHELXL-97 Sheldrick, G. M. SHELXL-97 [Programs for Crystal Structure Analysis (Release 97-2). University of Gδttingen, Germany (1997)].

Table 2

Table 3

Table 4

Table 5

Table 6

Table 7

Table 8

Table 9

Torsion angles [deg] for cardOOl.

Table 10

Table 11

Table 12

Table 13

Table 14

Table 15

Table 16

Table 17

Table 18

Table 19

Table 20

The present invention is not to be limited in scope by the specific embodiments described herein, since such embodiments are intended as but single illustrations of one aspect of the invention and any functionally equivalent embodiments are within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description and accompanying drawings. Such modifications are intended to fall within the scope of the appended claims.

All publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety. All publications, patents and patent applications mentioned herein are incorporated herein by reference for the purpose of describing and disclosing the domains, cell lines, vectors, methodologies etc. which are reported therein which might be used in connection with the invention. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.

Claims

CLAIMSWhat is claimed is:

1. A stable crystalline choline salt of oxypurinol.

2. A crystalline choline salt of oxypurinol as claimed in claim 1 comprising molecules of choline salts of oxypurinol held together by intermolecular bonding interactions comprises of hydrogen bonds.

3. A crystalline choline salt of oxypurinol as claimed in claim 1 which has the space group symmetry C2/c.

4. A crystalline choline salt of oxypurinol as claimed in claim 1 wherein the unit cell is monoclinic.

5. A crystalline choline salt of oxypurinol as claimed in claim 1 which has the dimensions a = 14.78 ± 0.01, b = 11.24 ± 0.01, c = 14.70 ± 0.01 or a = 14.82 ± 0.01, b= 11.22 ± 0.01, c = 14.72 ± 0.01.

6. A crystalline choline salt of oxypurinol salt as claimed in claim 1 that has enhanced solubility of oxypurinol compared to oxypurinol free acid.

7. A crystalline choline salt of oxypurinol as claimed in claim 1 having the atomic coordinates as shown in Table 5 or Table 14.

8. A composition comprising a stable and substantially purified crystalline choline salt of oxypurinol and a pharmaceutically acceptable carrier.

9. A composition of claim 8 which is a solid form pharmaceutical composition.

10. A composition of claim 9 which is a tablet, capsule, powder, sachet, pill, buccal, or pulverized form.

11. A crystalline form of oxypurinol as a choline salt, which can be processed galenically as stable, well-defined solid substances and which allows for prolonged stability in storage and for oral and intravenous administration of the drug

12. A method for preparing a crystalline choline salt of oxypurinol as claimed in claim 1 comprising treating oxypurinol with choline hydroxide, and purifying the choline salt by crystallization to yield a crystalline choline salt of oxypurinol.

13. A method for preventing and/or treating a condition and/or disease comprising administering to a subject an effective amount of a composition as claimed in claim 8.

14. A method of computationally evaluating a chemical entity for inhibition of xanthine oxidase comprising modeling the properties of said entity using atomic coordinates of the purified crystalline choline salt of oxypurinol as claimed in claim 1.

15. A crystalline choline salt of oxypurinol as claimed in claim 1 which is substantially purified.

16. A crystalline choline salt of oxypurinol as claimed in claim 15 having a purity of at least 95%, in particular a purity of at least 98%, more particularly greater than 99%, most particularly greater than 99.5%

17. A crystalline choline salt of oxypurinol having long-term stability to UV light, oxidation, heat and humidity.

18. An isolated, stable crystalline choline salt of oxypurinoL

19. A method for preventing and/or treating a condition and/or disease in a subject comprising administering an effective amount of a crystalline choline salt of oxypurinol of any preceding claim.

20. A method of claim 19 wherein the condition and/or disease is cardiovascular disease and related diseases, ischaemia-reperfusion injury in tissues including the heart, lung, kidney, gastrointestinal tract, and brain, diabetes, inflammatory joint diseases such as rheumatoid arthritis, respiratory distress syndrome, kidney disease, liver disease, sickle cell disease, sepsis, burns, viral infections, hemorrhagic shock, gout, hyperuricaemia, and conditions associated with excessive resorption of bone.