TITLE OF THE INVENTION

NOVEL CRYSTALLINE FORM OF A DIHYDROCHLORIDE SALT OF A DIPEPTIDYL PEPTIDASE-IV INHIBITOR

FIELD OF THE INVENTION

The present invention relates to a novel crystalline form of a dihydrochloride salt of a dipeptidyl peptidase-IV inhibitor. More particularly, the invention relates to a novel crystalline dihydrate form of the dihydrochloride salt of (2i?,35,5S)-2-(2,5-difluorophenyl)-5-(4,6-dihydropyrrolo[3,4 -c]pyrazol-5(lH)- yl)tetrahydro-2//-pyran-3 -amine, which is a potent inhibitor of the dipeptidyl peptidase- IV (DPP-4) enzyme. This novel crystalline form of the DPP-4 inhibitor is useful for the preparation of pharmaceutical compositions containing the inhibitor which are useful for the treatment and prevention of diseases and conditions for which an inhibitor of DPP-4 is indicated, in particular Type 2 diabetes, hyperglycemia, insulin resistance, obesity, and high blood pressure. The invention further concerns pharmaceutical compositions comprising the novel crystalline form of the present invention; processes for its preparation as well as processes for preparing pharmaceutical compositions containing this crystalline form; and methods of treating conditions for which a DPP-4 inhibitor is indicated comprising administering a pharmaceutical composition of the present invention.

BACKGROUND OF THE INVENTION

Inhibition of dipeptidyl peptidase-IV (DPP-4), an enzyme that inactivates both glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide 1 (GLP- 1), represents an established approach to the treatment and prevention of Type 2 diabetes, also known as non-insulin dependent diabetes mellitus (NIDDM). The therapeutic potential of DPP-4 inhibitors for the treatment of Type 2 diabetes has been widely reviewed: C. F. Deacon and J.J. Hoist, "Dipeptidyl peptidase IV inhibition as an approach to the treatment and prevention of Type 2 diabetes: a historical perspective," Biochem. Biophvs. Res. Commun.. 294: 1-4 (2000); K. Augustyns, et al., "Dipeptidyl peptidase IV inhibitors as new therapeutic agents for the treatment of Type 2 diabetes," Exp. Opin. Ther. Patents. 13: 499-510 (2003); DJ. Drucker, "Therapeutic potential of dipeptidyl peptidase IV inhibitors for the treatment of Type 2 diabetes," Exp. Opin. Investig. Drugs, 12: 87-100 (2003); Ann Weber, "Dipeptidyl Peptidase IV Inhibitors for the Treatment of

Diabetes," J. Med. Chem., 47: 4135-4141 (2004); K. Augustyns, et al., "Inhibitors of proline-specific dipeptidyl peptidases: DPP IV inhibitors as a novel approach for the treatment of Type 2 diabetes," Exp. Qpin. Ther. Patents, 15: 1387-1407 (2005); T. W. von Geldern, et al., ""The Next Big Thing in Diabetes: Clinical Progress on DPP-IV Inhibitors," Drug Development Research. 67: 627-642 (2006); and DJ. Drucker, et al., "The incretin system: GLP-I receptor agonists and dipeptidyl peptidase-4 inhibitors in type 2 diabetes," Lancet, 368: 1696-1705 (2006).

(2i?,35',55)-2-(2,5-Difluorophenyl)-5-(4,6-dihydropyπOlo [3,4-c]pyrazol- 5(li/)-yl)tetrahydro-2H-pyran-3-amine dihydrochloride of structural formula I below (hereinafter referred to as Compound I) is a potent inhibitor of DPP-4 with potential for the treatment of Type 2 diabetes and obesity. The instant invention constitutes the first disclosure of crystalline forms of Compound I.

SUMMARY OF THE INVENTION The present invention is concerned with a novel crystalline form of the dihydrochloride salt of the specific DPP-4 inhibitor (2i?,3,S',55)-2-(2,5-difIuorophenyl)-5- (4,6-dihydropyrrolo[3,4-c]pyrazol-5(lH)-yl)tetrahydro-2//-py ran-3-amine. The crystalline form of the present invention has advantages in the preparation of pharmaceutical compositions of the dihydrochloride salt of (2R,3S,5S)-2-(2,5- difluorophenyl)-5-(4,6-dihydropyrrolo[3,4-c]pyrazol-5(lH)-yl )tetrahydro-2//-pyran-3- amine, such as ease of processing, handling, and dosing. In particular, it exhibits improved physical and chemical stability over the amorphous form, such as stability to stress, high temperatures and humidity, as well as improved physicochemical properties, such as lack of stickiness, solubility and rate of solution, rendering it particularly suitable for the manufacture of various pharmaceutical dosage forms containing Compound I.

The invention also concerns pharmaceutical compositions containing the novel crystalline form; processes for its preparation and its pharmaceutical compositions; and methods for using them for the prevention or treatment of Type 2 diabetes, hyperglycemia, insulin resistance, obesity, and high blood pressure.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a characteristic X-ray diffraction pattern of the crystalline dihydrate of Compound I of the present invention.

FIG. 2 is a characteristic carbon- 13 cross-polarization magic-angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectrum of the crystalline dihydrate of Compound I of the present invention.

FIG. 3 is a characteristic fluorine- 19 magic-angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectrum of the crystalline dihydrate of Compound I of the present invention.

FIG. 4 is a characteristic thermogravimetric analysis (TGA) curve of the crystalline dihydrate of Compound I of the present invention.

FIG. 5 is a characteristic differential scanning calorimetry (DSC) curve of the crystalline dihydrate of Compound I of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

This invention provides a novel crystalline form of the dihydrochloride salt of (2i?,35',55)-2-(2,5-difluorophenyl)tetrahydro)-5-(4,6-dihydr opyrrolo[3,4-c]pyrazol- 5(lH)-yl)tetrahydro-2H-pyran-3-amine of structural formula I (Compound I):

(I)

In one embodiment the novel crystalline dihydrochloride salt is in the form of a crystalline hydrate.

In one embodiment the novel crystalline dihydrochloride salt is in the form of a crystalline dihydrate.

A further embodiment of the present invention provides a drug substance of Compound I that comprises the crystalline dihydrate form of the present invention in a detectable amount. By "drug substance" is meant the active pharmaceutical ingredient ("API"). The amount of the crystalline dihydrate form in the drug substance can be quantified by the use of physical methods such as X-ray powder diffraction (XRPD), solid-state fluorine- 19 magic-angle spinning (MAS) nuclear magnetic resonance

spectroscopy, solid-state carbon- 13 cross-polarization magic-angle spinning (CPMAS) nuclear magnetic resonance spectroscopy, solid state Fourier-transform infrared spectroscopy, and Raman spectroscopy. In a class of this embodiment, about 5% to about 100% by weight of the crystalline dihydrate form is present in the drug substance, hi a second class of this embodiment, about 10% to about 100% by weight of the crystalline dihydrate form is present in the drug substance, hi a third class of this embodiment, about 25% to about 100% by weight of the crystalline dihydrate form is present in the drug substance, hi a fourth class of this embodiment, about 50% to about 100% by weight of the crystalline dihydrate form is present in the drug substance, hi a fifth class of this embodiment, about 75% to about 100% by weight of the crystalline dihydrate form is present in the drug substance. In a sixth class of this embodiment, substantially all of the drug substance is the crystalline dihydrate form, i.e., the drug substance is substantially phase pure crystalline dihydrate form.

Another aspect of the present invention provides a method for the prevention or treatment of clinical conditions for which an inhibitor of DPP-4 is indicated, which method comprises administering to a patient in need of such prevention or treatment a prophylactically or therapeutically effective amount of the crystalline dihydrate form of Compound I. Such clinical conditions include diabetes, in particular Type 2 diabetes, hyperglycemia, insulin resistance, obesity, and high blood pressure. The present invention also provides for the use of the crystalline dihydrate form of Compound I of the present invention in the manufacture of a medicament for the prevention or treatment of clinical conditions for which an inhibitor of DPP-4 is indicated, in particular, Type 2 diabetes, hyperglycemia, insulin resistance, obesity, and high blood pressure, hi one embodiment the clinical condition is Type 2 diabetes. Another aspect of the present invention provides the crystalline dihydrate form of Compound I for use in the treatment of clinical conditions for which an inhibitor of DPP-4 is indicated, in particular, diabetes, hyperglycemia, insulin resistance, obesity, and high blood pressure. In one embodiment of this aspect the clinical condition is Type 2 diabetes. The present invention also provides pharmaceutical compositions comprising the crystalline dihydrate form of Compound I, in association with one or more pharmaceutically acceptable carriers or excipients. In one embodiment the pharmaceutical composition comprises a prophylactically or therapeutically effective amount of the active pharmaceutical ingredient ("API") in admixture with pharmaceutically acceptable excipients wherein the API comprises a detectable amount of

the crystalline dihydrate form of Compound I of the present invention. In a second embodiment the pharmaceutical composition comprises a prophylactically or therapeutically effective amount of the API in admixture with pharmaceutically acceptable excipients wherein the API comprises about 5% to about 100% by weight of the crystalline dihydrate form of Compound I of the present invention, hi a class of this second embodiment, the API in such compositions comprises about 10% to about 100% by weight of the crystalline dihydrate form of Compound I. In a second class of this embodiment, the API in such compositions comprises about 25% to about 100% by weight of the crystalline dihydrate form of Compound I. In a third class of this embodiment, the API in such compositions comprises about 50% to about 100% by weight of the crystalline dihydrate form of Compound I. In a fourth class of this embodiment, the API in such compositions comprises about 75% to about 100% by weight of the crystalline dihydrate form of Compound I. In a fifth class of this embodiment, substantially all of the API is the crystalline dihydrate form of Compound I, i.e., the API is substantially phase pure Compound I crystalline dihydrate form.

The compositions in accordance with the invention are suitably in unit dosage forms such as tablets, pills, capsules, powders, granules, sterile solutions or suspensions, metered aerosol or liquid sprays, drops, ampoules, auto-injector devices or suppositories. The compositions are intended for oral, parenteral, intranasal, sublingual, or rectal administration, or for administration by inhalation or insufflation. Formulation of the compositions according to the invention can conveniently be effected by methods known from the art, for example, as described in Remington's Pharmaceutical Sciences, 17 ^th ed., 1995.

The dosage regimen is selected in accordance with a variety of factors including type, species, age, weight, sex and medical condition of the patient; the severity of the condition to be treated; the route of administration; and the renal and hepatic function of the patient. An ordinarily skilled physician, veterinarian, or clinician can readily determine and prescribe the effective amount of the drug required to prevent, counter or arrest the progress of the condition. Oral dosages of the present invention, when used for the indicated effects, will range between about 0.01 mg per kg of body weight per day (mg/kg/day) to about 100 mg/kg/day, preferably 0.01 to 10 mg/kg/day, and most preferably 0.1 to 5.0 mg/kg/day. For oral administration, the compositions are preferably provided in the form of tablets containing 0.01, 0.05, 0.1, 0.5, 1.0, 2.5, 5.0, 10.0, 15.0, 25.0, 50.0, 100 and 500 milligrams of the API for the symptomatic adjustment of the dosage to the patient to be

treated. A medicament typically contains from about 0.01 mg to about 500 mg of the API, preferably, from about 1 mg to about 200 mg of API. Intravenously, the most preferred doses will range from about 0.1 to about 10 mg/kg/minute during a constant rate infusion. Advantageously, the crystalline dihydrate forms of the present invention may be administered in a single daily dose, or the total daily dosage may be administered in divided doses of two, three or four times daily. Furthermore, the crystalline dihydrate forms of the present invention can be administered in intranasal form via topical use of suitable intranasal vehicles, or via transdermal routes, using those forms of transdermal skin patches well known to those of ordinary skill in the art. To be administered in the form of a transdermal delivery system, the dosage administration will, of course, be continuous rather than intermittent throughout the dosage regimen.

In the methods of the present invention, the Compound I crystalline dihydrate form herein described in detail can form the API, and is typically administered in admixture with suitable pharmaceutical diluents, excipients or carriers (collectively referred to herein as 'carrier' materials) suitably selected with respect to the intended form of administration, that is, oral tablets, capsules, elixirs, syrups and the like, and consistent with conventional pharmaceutical practices.

For instance, for oral administration in the form of a tablet or capsule, the active pharmaceutical ingredient can be combined with an oral, non-toxic, pharmaceutically acceptable, inert carrier such as lactose, starch, sucrose, glucose, methyl cellulose, magnesium stearate, dicalcium phosphate, calcium sulfate, mannitol, sorbitol and the like; for oral administration in liquid form, the oral API can be combined with any oral, non-toxic, pharmaceutically acceptable inert carrier such as ethanol, glycerol, water and the like. Moreover, when desired or necessary, suitable binders, lubricants, disintegrating agents and coloring agents can also be incorporated into the mixture. Suitable binders include starch, gelatin, natural sugars such as glucose or beta-lactose, corn sweeteners, natural and synthetic gums such as acacia, tragacanth or sodium alginate, carboxymethylcellulose, polyethylene glycol, waxes and the like. Lubricants used in these dosage forms include sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and the like. Disintegrators include, without limitation, starch, methyl cellulose, agar, bentonite, xanthan gum and the like.

The crystalline dihydrate form of Compound I possesses a high solubility in water, rendering them especially amenable to the preparation of formulations, in particular intranasal and intravenous formulations, which require relatively concentrated aqueous solutions of the API. The solubility of the crystalline dihydrate form of

Compound I in water is and 0.5% Methocel is greater than 125 mg/mL (native pH about

3.0).

In a still further aspect, the present invention provides a method for the treatment and/or prevention of clinical conditions for which a DPP -4 inhibitor is indicated, which method comprises administering to a patient in need of such prevention or treatment a prophylactically or therapeutically effective amount of the crystalline dihydrate form of the present invention or a pharmaceutical composition containing a prophylactically or therapeutically effective amount of crystalline dihydrate form of

Compound I. The following non-limiting Examples are intended to illustrate the present invention and should not be construed as being limitations on the scope or spirit of the instant invention. All temperatures are degrees Celsius unless otherwise indicated.

Compounds described herein may exist as tautomers such as keto-enol tautomers. The individual tautomers as well as mixtures thereof are encompassed with compounds of structural formula I.

EXAMPLE 1

Intermediate 1 :

ter/-Butyl r(2i?.3^-5-oxo-2-(2,5-difluorophenyl)tetrahvdro-2H-pyran-3-y llcarbamate Step A: l-(2,5-Difluorophenyl)-2-nitroethanol

To sodium hydroxide (IN, 3L) and methanol (1500 mL) at 5 ⁰ C was added a solution of 2,5-difluorobenzaldehyde (350 g, 2.46 mol) and nitromethane (157 mL, 2.9 mol) in methanol (350 mL) dropwise over a period of 1 h. The reaction mixture was then neutralized with glacial acetic acid (165 mL). Aqueous workup gave the desired nitroalcohol.

Step B: 2-Nitro- 1 -(2,5-difluorophenyl ^" )ethanone

A solution of Dess-Martin periodinane (125 g) in dichloromethane (600 mL) was added to a solution of the nitroalcohol made in Step A (46.3 g) at 10 ⁰ C over a period of 30 min. Stirring was continued for 2 h, and the reaction mixture was then poured onto a mixture of sodium bicarbonate (300 g) and sodium thiosulfate (333 g) in water (3 L). The desired product was extracted with methyl t-butyl ether (MTBE) (2 L). The aqueous layer was neutralized with HCl (2N, 1.5 L) and extracted with MTBE (3 L). The combined organic layers were dried over anhydrous magnesium sulfate, filtered, evaporated and the residue was purified by chromatography (silica gel, eluting with dichloromethane) to yield the desired nitroketone.

Step C: 3 -Iodo-2-f iodomethvDprop- 1 -ene

A mixture of 3-chloro-2-(chloromethyl)prop-l-ene (1.0 g, 8 mmol) and sodium iodide (6.6 g, 44 mmol) in acetone (60 mL) was stirred at room temperature for 20 h, evaporated under reduced pressure and partitioned between dichloromethane (150 mL) and water (50 mL). The organic layer was dried over sodium sulfate, filtered and evaporated to yield 3-iodo-2-(iodomethyl)prop-l-ene as a reddish oil.

Step D: 3-Methylene-5-nitro-6-r2,5-difluorophenylV3,4-dihydro-2//-py ran

λfN-diisopropylethylamine (184 mL) was added to a solution of 2-nitro-l- (2,5-difluorophenyl)ethanone (92.7 g, 461 mmol) in N,N-dimethylformamide (1000 mL) and 3-iodo-2-(iodomethyl)prop-l-ene (156 g, 507 mmol). The mixture was heated at 60

⁰ C for 2 h, evaporated and purified by chromatography (silica gel, gradient 0-30% dichloromethane in hexane) to yield 3-methylene-5-nitro-6-(2,5-difluorophenyl)-3,4- dihydro-2H-pyran.

Step E: (2./?,35)-5-Methylene-3-nitro-2-(2,5-difluorophenyl)tetrahvd ro-2H-pyran

This compound was made by following the same method described in

Intermediate 1, Step D.

Step F: r2i?.3^-5-Methylene-2-r2.5-difluorophenvntetrahvdro-2H-pyran -3-amine

This compound was made by following the same method described in Intermediate 1, Step E.

Step G: tert-Butyl r(2/USy5-methylene-2-(Z5-difluorophenvOtetrahvdro-2H- pyran-3-vHcarbamate

This compound was made by following the same method described in Intermediate 1, Step F.

Step H: fert-Butyl r(2Jg.35)-5-hvdroxy-5-(hvdroxymethvn-2-(2.5- difluorophenvPtetrahydro-ZH-pyran-S-ylicarbamate

This compound was made by following the same method described in Intermediate 1, Step G.

Step I: fert-Butyl r(2ig.35 ^r )-5-oxo-2-(2.5-difluorophenyl)tetrahydro-27f-pyran-3- yll carbamate

To a solution of tert-butyl [(2i?,35)-5-hydroxy-5-(hydroxymethyl)-2-(2,5- trifluorophenyl)tetrahydro-2//-pyran-3-yl]carbamate (10.5 g) in methanol (100 mL) at 0 ⁰ C was added pyridine (7.8 mL) and lead tetraacetate (21.7 g). The reaction mixture was stirred for 20 min. Aqueous work-up with ethyl acetate gave crude product which was purified by chromatography (silica, 0-50% ethyl acetate/heptane) to yield tert-butyl

[(2i?,3S)-5-oxo-2-(2,5-difluorophenyl)tetrahydro-2H-pyran -3-yl]carbamate as white solid.

Intermediate 2:

NHλ

L >NH

Step A: tert-Butyl f 3Z)-3-r(^imethylamino)methylenel-4-oxopyrrolidine- 1 - carboxylate

A solution of tert-butyl 3-oxopyrrolidine-l-carboxylate (40 g, 216 mmol) was treated with DMF-DMA (267 g, 2241 mmol) and heated at 105 ⁰ C for 40 min. The solution was cooled and evaporated under reduced pressure and the resulting orange solid was treated with hexane (200 mL) and cooled in the refrigerator over the weekend. The resulting brownish-yellow solid was collected by filtration, dried and used in the next setp without further purification.

Step B: tert-Butyl 4.6-dihvdropyrrolo[3,4-c1pyrazole-5(lH)-carboxylate A solution of hydrazine (3 mL) and tert-butyl (3Z)-3-

[(dimethylamino)methylene]-4-oxopyrrolidine-l-carboxylate (19.22 g) in ethanol (40

mL) was heated at 85 ⁰ C in a sealed tube for 4 h. Solvent was removed under reduced pressure, and the residue was triturated with dichloromethane (160 mL) and ethyl acetate (15 mL). The resulting solid was filtered. The filtrate was concentrated and the resulting solid was triturated again. The combined solids were used in the next step.

Step C: 1 A5,6-Tetrahvdropyrrolo[3 _, 4-c ^' [pyrazole tert-Butyl 4,6-dihydropyrrolo[3,4-c]pyrazole-5(lH)-carboxylate (12.7 g) obtained in Step B above was treated with 4N hydrochloric acid (250 mL) in methanol and stirred for 6 h. The reaction mixture was concentrated and dried. The step was repeated. 12 g of the HCl salt so obtained was treated with ammonia in methanol (2N, 300 mL) and ammonium hydroxide solution in water (28%, 30 mL) and concentrated to dryness. The solid obtained was treated with methanol (70 mL) and water (5 mL) and purified in three batches on Biotage Horizon® system (silica, gradient 5-17% methanol containing 10% concentrated ammonium hydroxide in ethyl acetate) to yield 1,4,5,6- tetrahydropyrrolo[3,4-c]pyrazole. lH NMR (500 MHz, CD3OD): δ 4.04 (d, 4H), 7.39(s, IH).

EXAMPLE 1

Step A: fert-Butyl r(2iU£,557-2-(2,5-difluorophenviy5-(4,6-dihvdropyπOlor3,4- c]pyrazol-5(lH)-yl)tetrahvdro-2//-pyran-3-yllcarbamate

A solution of Intermediate 1 (6.03 g, 18.4 mmol) and Intermediate 2 (2.61 g, 23.94 mmol) in methanol (135 mL) was stirred for 30 min and then treated with decaborane (674 mg, 5.53 mmol). The mixture was stirred overnight and evaporated under reduced pressure. The residue was purified on Horizon® (silica, successive elution with ethyl acetate (6 L), 5-6% ethanol containing 10% ammonium hydroxide in ethyl acetate (2 L), 8-12% ethanol containing 10% ammonium hydroxide in ethyl acetate (3 L)

to yield the title compound as the less-mobile diastereoisomer (silica, TLC 6% methanol containing 10% ammonia in dichloromethane). lH NMR (500 MHz, CD ₃ OD): δ 1.18- 1.24 (m, 9H), 1.59-1.65 (q, IH), 2.4 (m, IH), 3.06 (m, IH), 338 (m, IH), 3.75 (m, IH), 3.86 (m, 4H), 4.30 (m, IH), 4.35 (d, IH, J = IO Hz), 7.02 (m, 2H), 7.20 (m, IH), 7.38 (s, IH).

(2JU£55V2-α5-Difluorophenyl>5-f4.6-dihvdropyrrolor3. 4- c1pyrazol-5d//)-yl)tetrahydro-2H-pyran-3-amine, dihydrochloride dihydrate

tert-Butyl [(2i?,35',5i?)-2-(2,5-difluorophenyl)-5-(4,6-dihydropyrrolo[ 3,4- c]pyrazol-5(lH)-yl)tetrahydro-2//-pyran-3-yl]carbamate (5 g) from Step A was dissolved in a solution of hydrogen chloride (300 mL, 3iVin ethyl acetate) and stirred for 3 h. The solution was evaporated, redissolved in 200 mL methanol and evaporated again to remove traces of residual hydrogen chloride. The residue was triturated with ethanol (50 mL) and methanol (4 mL) to afford the title compound as an amorphous solid. lH NMR (500 MHz, CD ₃ OD): δ 2.27 (dd, IH, J = 11.7, 23.6 Hz), 2.90-2.92 (m, IH), 3.67-3.70 (m, IH), 3.94 (t, IH, J = 1 IHz), 4.15-4.19 (m, IH), 4.54 (m, IH), 4.72 (br, 4H), 4.78 (d, IH, J = 10.3 Hz), 7.24 (m, 2H), 7.34 (m, IH), 7.63 (s, IH); LC-MS 321.3 (M+l). The amorphous solid was exposed to increasing humidity conditions from

5-95% at 25° on a vapor sorption isotherm instrument using a step isotherm program for relative humidity. The sample was first dried at 40° and 5% relative humidity (RH). The RH was then ramped up to 95%, after which it was stepped back to 5% (in 5% increments). At 60% RH, there was an 8% water uptake at 25°, corresponding to about 2 moles of water. After desorption of the material, a white crystalline solid powder remained which was used as seeds in Example 2 below.

EXAMPLE 2

Step B: (lR.35,55)-2-(2,5-Difluorophenvn-5-(4.6-dihvdropyrrolor3.4- c]pyrazol-5 ( 1 //)-yπtetrahydro-2H-pyran-3 -amine, dihydrochloride dihydrate To a mixture of tert-butyl [(2i?,35,55>2-(2,5-difluorophenyl)-5-(4,6- dihydropyrrolo[3,4-c]pyrazol-5(l//)-yl)-tetrahydro-2H-pyran- 3-yl carbamate (Example 1, Step A) (103.5 g, 0.2462 mol) in ethanol (725 mL) and water (20.7 mL) was added concentrated hydrochloric acid (81.4 mL) dropwise. The reaction mixture was aged at 55° for 30-60 min and then seeded with crystalline dihydrate from Example 1. The mixture was aged for an additional 5 h. The reaction slurry was cooled to ambient temperature. Isopropyl acetate (520 mL) was added drpwise over 2 h. The batch was aged at ambient temperature for 2 h. After filtration, the wet cake was washed with 30% ethanol/ 70% isopropyl acetate/2% water (2 x 250 mL) followed by 10% ethanol/ 90% isopropyl acetate (250 mL). The solid was suction dried under nitrogen at 30-70% RH to give the dihydrochloride salt dihydrate as a white, highly crystalline, non-hygroscopic powder. HPLC area percent purity was measured at greater than 99%.

This powder was found to be physically stable at greater than 5% relative humidity (RH) at ambient temperature. It was also observed to be stable up to 90° in a strong acidic aqueous environment (pH = 1). Moreover, the powder was +found to be chemically stable for over 9 weeks at 40° and 75% RH and at 607ambient humidity.

X-ray powder diffraction studies are widely used to characterize molecular structures, crystallinity, and polymorphism. The X-ray powder diffraction pattern of the crystalline dihydrate of Compound I was generated on a Philips Analytical X'Pert PRO X-ray Diffraction System with PW3040/60 console. A PW3373/00 ceramic Cu LEF X- ray tube K- Alpha radiation was used as the source.

Figure 1 shows an X-ray diffraction pattern for the crystalline dihydrate of Compound I. The crystalline dihydrate exhibited characteristic diffraction peaks corresponding to 2-theta values of 8.5, 14.7, and 22.9 degrees. The dihydrate was further characterized by diffraction peaks corresponding to 2-theta values of 13.7, 15.3, and 19.5 degrees. The dihydrate was even further characterized by diffraction peaks corresponding to 2-theta values of 20.3, 21.9, and 23.4 degrees.

In addition to the X-ray powder diffraction pattern described above, the crystalline dihydrate of Compound I was further characterized by its solid-state carbon- 13, fluorine- 19 nuclear magnetic resonance (NMR) spectra, its differential scanning calorimetry (DSC) curve, and by thermogravimetric analysis (TGA).

The solid-state carbon- 13 NMR spectrum was obtained on a Bruker DSX 500WB NMR system using a Bruker 4 mm H/X/Y CPMAS probe. The carbon- 13 NMR spectrum utilized proton/carbon- 13 cross-polarization magic-angle spinning with variable-amplitude cross polarization, total sideband suppression, and SPINAL decoupling at lOOkHz. The sample was spun at 10.0 kHz, and a total of 10240 scans were collected with a recycle delay of 10 seconds. A line broadening of 10 Hz was applied to the spectra before FT was performed. Chemical shifts are reported on the TMS scale using the carbonyl carbon of glycine (176.03 p.p.m.) as a secondary reference.

The solid-state fluorine- 19 NMR spectrum was obtained on a Bruker DSX 500WB NMR system using a Bruker 4 mm H/F/X CPMAS probe. The fluorine- 19 NMR spectrum utilized proton/ fluorine- 19 cross-polarization magic-angle spinning with variable-amplitude cross polarization, and TPPM decoupling at 62.5kHz. The sample was spun at 15.0 kHz, and a total of 512 scans were collected with a recycle delay of 5 seconds. A line broadening of 10 Hz was applied to the spectrum before FT was performed. Chemical shifts are reported using poly(tetrafluoroethylene) (Teflon®) as an external secondary reference which was assigned a chemical shift of -122 ppm.

Figure 2 shows a characteristic solid-state carbon- 13 CPMAS NMR spectrum for the crystalline dihydrate of Compound I. The crystalline dihydrate exhibited characteristic signals with chemical shift values of 67.8, 52.1, 149.0, and 118.8 p.p.m. Further characteristic of the crystalline dihydrate were the signals with chemical shift values of 113.8, 31.7, 57.5, and 74.3 p.p.m. The crystalline dihydrate was even further characterized by signals with chemical shift values of 49.2, 21.3, and 158.5 p.p.m.

Figure 3 shows a characteristic solid-state fluorine- 19 CPMAS NMR spectrum for the crystalline dihydrate of Compound I. The crystalline dihydrate exhibited characteristic signals with chemical shift values of -119.6 and -113.7 p.p.m.

Figure 4 shows a characteristic TGA curve for the crystalline dihydrate of Compound I. A Perkin Elmer model TGA 7 or equivalent instrument was used. Experiments were performed under a flow of nitrogen and using a heating rate of 10 °C/min to a maximum temperature of approximately 300°. After automatically taring the balance, 1 to 20 mg of sample was added to the platinum pan, the furnace was raised, and the heating program was started. Weight/temperature data were collected automatically by the instrument. Analysis of the results was carried out by selecting the Delta Y function within the instrument software and choosing the temperatures between which the weight loss was to be calculated. Weight losses are reported up to the onset of decomposition/evaporation. TGA indicated a weight loss of about 0.5% from about 25°C

to about 49° corresponding to residual moisture and a 8.4% loss from about 50° to about 150° corresponding to the dihydrate.

Figure 5 shows a characteristic DSC curve for the crystalline dihydrate of Compound I. A TA Instruments DSC 2910 or equivalent instrumentation was used. Between 1 and 6 mg sample was weighed into an open pan. This pan was then crimped and placed at the sample position in the calorimeter cell. An empty pan was placed at the reference position. The calorimeter cell was closed and a flow of nitrogen was passed through the cell. The heating program was set to heat the sample at a heating rate of 10 °C/min to a temperature of approximately 300°. The heating program was started. When the run was completed, the data were analyzed using the DSC analysis program contained in the system software. The dehydration endotherm was integrated between baseline temperature points that are above and below the temperature range over which the endotherm is observed. The data reported are the onset temperature, peak temperature and enthalpy. The DSC curve is characterized by an endotherm associated with loss of water from the lattice with an onset temperature of 100.5°, a peak temperature of 110.9°, and associated enthalpy of 220.2 J/g. Melting of the dehydrated form is accompanied by decomposition. The onset temperature of this melting is 223.7°.

The crystalline form of Compound I of the present invention has a phase purity of at least about 5% of dihydrate with the above X-ray powder diffraction, fluorine- 19 MAS NMR, carbon- 13 CPMAS NMR, and DSC physical characteristics. In one embodiment the phase purity is at least about 10% of the dihydrate with the above solid- state physical characteristics. In a second embodiment the phase purity is at least about 25% of the dihydrate with the above solid-state physical characteristics. In a third embodiment the phase purity is at least about 50% of the dihydrate with the above solid- state physical characteristics. In a fourth embodiment the phase purity is at least about 75% of the dihydrate with the above solid-state physical characteristics. In a fifth embodiment the phase purity is at least about 90% of the dihydrate with the above solid- state physical characteristics. In a sixth embodiment the crystalline form of Compound I is the substantially phase pure dihydrate with the above solid-state physical characteristics. By the term "phase purity" is meant the solid state purity of the crystalline form of Compound I with regard to another particular polymorph of the crystalline dihydrate form of the present invention, a pseudopolymorph, or amorphous form of Compound I as determined by the solid-state physical methods described in the present application.

EXAMPLE OF A PHARMACEUTICAL COMPOSITION: Roller compaction process:

The dihydrochloride crystalline dihydrate ("API") was formulated into a tablet by a roller compaction process. A 40-mg potency tablet is composed of 53.6 mg of the API, 203.6 mg microcrystalline cellulose, 203.6 mg of Pearlitol SD 100 (a brand of mannitol), 14.4 mg of croscarmellose sodium, and 4.8 mg of magnesium stearate. The API, microcrystalline cellulose, Pearlitol, and croscarmellose sodium were first blended, and the mixture was then lubricated with one half the total amount of magnesium stearate and roller compacted into ribbons. These ribbons were then milled and the resulting granules were lubricated with the remaining amount of the magnesium stearate and then encapsulated into opaque white hydroxypropylmethylcellulose (HPMC) capsules (Size 00) (total capsule weight of 480 mg).