WO2003050116A1

WO2003050116A1 - A 5(-4-(2-(n-methyl-n-(2-pyridil)amino)ethoxy)benzyl)thiazolidine-2,4-dione (i) 10-camphorsulphonic acid salt and use against diabetes mellitus

Info

Publication number: WO2003050116A1
Application number: PCT/GB2002/005678
Authority: WO
Inventors: Tim Chien Ting Ho
Original assignee: SmithKline Beecham Ltd
Current assignee: SmithKline Beecham Ltd
Priority date: 2001-12-13
Filing date: 2002-12-13
Publication date: 2003-06-19
Anticipated expiration: 2004-06-13
Also published as: AU2002352391A1

Abstract

A 5[-4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione 10-Camphorsulfonate salt, a process for preparing such a salt, a pharmaceutical composition containing such as salt and the use of such a salt in medicine.

Description

- (4 - ( 2- (N- ETHYL-N- ( 2- PYRIDYL) AMIN0) ETH0XY) BENZYL) THIAZOLIDINE-2 , 4 -DIONE ( I ) 1 0-CAMPHORSULFONIC ACID SALT AND USE AGAINST DIABETES MELLITUS

This invention relates to a novel pharmaceutical, to a process for the preparation of the pharmaceutical and to the use of the pharmaceutical in medicine. European Patent Application, Publication Number 0,306,228 relates to certain thiazolidinedione derivatives disclosed as having hypoglycaemic and hypolipidaemic activity. The compound of Example 30 of EP 0,306,228 is 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (hereinafter also referred to as "Compound (I)"). International Patent Application, Publication Number WO 94/05659 discloses certain salts of the compounds of EP 0,306,228. The preferred salt of WO 94/05659 is the maleic acid salt.

There remains a need for alternative salt forms which have properties suitable for pharmaceutical processing on a commercial scale. We have now prepared a 10-camphorsulfonic acid salt of Compound (I)

[hereinafter also referred to as the "Camphorsulfonate "] that is particularly stable and hence suitable for bulk preparation and handling. The novel Camphorsulfonate is a high melting crystalline material hence is amenable to large scale pharmaceutical processing, especially in manufacturing processes which require or generate heat, for example milling, fluid bed drying, spray drying, hot melt processing and sterilisation by autoclaving. The novel Camphorsulfonate can be prepared by an efficient, economic and reproducible process particularly suited to large-scale preparation.

The novel Camphorsulfonate exists in several stereochemical forms, each of which forms a separate aspect of this invention. The novel Camphorsulfonate also has useful pharmaceutical properties and in particular it is indicated to be useful for the treatment and/or prophylaxis of diabetes mellitus, conditions associated with diabetes mellitus and certain complications thereof. Accordingly, the present invention provides a camphorsulfonic acid salt of 5-[4- [2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione. 10-Camphorsulfonic acid is a chiral molecule and hence can exist in one or more stereochemical forms, for example (\R)-(-), (lS)-(+) or (±). The Camphorsulphonate can therefore exist in one or more stereochemical forms. The present invention encompasses all forms of the Camphorsulfonate.

Thus, in one aspect, the present invention provides 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (1 R)-(-)- 10-camphorsulfonate salt (the (li?)-(-)-10-Camphorsulfonate). In a further aspect, the present invention provides 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione ( 1 S)-(+)- 10-camphorsulfonate salt (the (lS)-(+)-10-Camphorsulfonate).

In yet a further aspect, the present invention provides 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (+)-l O-camphorsulfonate salt (the (±)- 10-Camphorsulfonate).

In one favoured aspect, the (li?)-(-)-10-Camphorsulfonate provides an infrared spectrum substantially in accordance with Figure 1.

In one favoured aspect, the (li?)-(-)-10-Camphorsulfonate provides a Raman spectrum substantially in accordance with Figure 2.

In one favoured aspect, the (li?)-(-)-10-Camphorsulfonate provides an X-Ray powder diffraction pattern (XRPD) substantially in accordance with Table 1 or Figure 3.

In one favoured aspect, the (lfl)-(-)-10-Camphorsulfonate provides a Solid State ¹³C NMR spectrum substantially in accordance with Figure 4. The (lJ?)-(-)-10-Camphorsulfonate has a melting point in the range of from 145 to

165 c, such as 150 to 160^OC, for example 154.8 -155.6 °C.

In a preferred aspect, the invention provides 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione, ( 1 R)-(-)- 10-Camphorsulfonate salt, characterised in that it provides: (i) an infrared spectrum substantially in accordance with Figure 1 ; and (ii) a Raman spectrum substantially in accordance with Figure 2; and (iii) an X-Ray powder diffraction pattern (XRPD) substantially in accordance with Table 1 or Figure 3; and

(iv) a Solid State ¹³C NMR spectrum substantially in accordance with Figure 4. In one favoured aspect, the (15)-(+)-10-Camphorsulfonate provides an infrared spectrum substantially in accordance with Figure 5.

In one favoured aspect, the (lS)-(+)-10-Camphorsulfonate provides a Raman spectrum substantially in accordance with Figure 6.

In one favoured aspect, the (lS)-(+)-10-Camphorsulfonate provides an X-Ray powder diffraction pattern (XRPD) substantially in accordance with Table 2 or Figure 7.

In one favoured aspect, the (lS)-(+)-10-Camphorsulfonate provides a Solid State ¹³C NMR spectrum substantially in accordance with Figure 8.

The (lS)-(+)-10-Camphorsulfonate has a melting point in the range of from 145 to 165 °C, such as 150 to 160°C, for example 153.7-154.9 °C . In a preferred aspect, the invention provides 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (lS)-(+)-10-Camphorsulfonate salt, characterised in that it provides: (i) an infrared spectrum substantially in accordance with Figure 5; and

(ii) a Raman spectrum substantially in accordance with Figure 6; and

(iii) an X-Ray powder diffraction pattern (XRPD) substantially in accordance with Table

2 or Figure 7; and (iv) a Solid State ¹³C NMR spectrum substantially in accordance with Figure 8. In one favoured aspect, the (±)-lO-Camphorsulfonate provides an infrared spectrum substantially in accordance with Figure 9.

In one favoured aspect, the (±)-lO-Camphorsulfonate provides a Raman spectrum substantially in accordance with Figure 10. In one favoured aspect, the (±)- 10-Camphorsulfonate provides an X-Ray powder diffraction pattern (XRPD) substantially in accordance with Table 3 or Figure 11.

In one favoured aspect, the (±)-lO-Camphorsulfonate provides a Solid State ¹³C NMR spectrum substantially in accordance with Figure 12.

The (+)-10-Camphorsulfonate provides a melting point in the range of from 160 to 180 °C, such as 165 to 173°C, for example 168.3-169.7 °C .

In a preferred aspect, the invention provides 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (+)- 10-Camphorsulfonate salt, characterised in that it provides:

(i) an infrared spectrum substantially in accordance with Figure 9; and (ii) a Raman spectrum substantially in accordance with Figure 10;and

3 or Figure 11 ; and

(iv) a Solid State ¹³C NMR spectrum substantially in accordance with Figure 12. The present invention encompasses the Camphorsulfonate or a solvate thereof isolated in pure form or when admixed with other materials.

Thus in one aspect there is provided the Camphorsulfonate or a solvate thereof in isolated form.

In a further aspect there is provided the Camphorsulfonate or a solvate thereof in pure form. In yet a further aspect there is provided the Camphorsulfonate or a solvate thereof in crystalline form.

Also, the invention provides the Camphorsulfonate or solvate thereof in a solid pharmaceutically acceptable form, such as a solid dosage form, especially when adapted for oral administration. Moreover, the invention also provides the Camphorsulfonate, or a solvate thereof, in a pharmaceutically acceptable form, especially in bulk form, such form being particularly capable of pharmaceutical processing, especially in manufacturing processes which require or generate heat.

Examples of manufacturing processes which require or generate heat include milling, heat-drying especially fluid-bed drying, spray drying or hot melt processing and heat-sterilisation such as autoclaving. Particular examples of manufacturing processes which require or generate heat include milling, heat-drying especially fluid-bed drying, spray drying or heat-sterilisation such as autoclaving.

Accordingly, the invention provides the Camphorsulfonate, or a solvate thereof, in a pharmaceutically acceptable form, especially in a bulk form.and especially in a form having been processed in a manufacturing process requiring or generating heat, for example in a milled form; for example in a heat-dried form, especially a fluid-bed dried form or a spray dried form; for example in a form having being hot melt processed; for example in a form having being heat-sterilised by such as autoclaving.

Suitable texts decribing the manufacturing processes referred to herein include "The Theory and Practice of Industrial Pharmacy" edited by Leon Lachman, Herbert A.

Lieberman and Joseph L. Kanig, published by Lea & Febiger and for spray drying and fluid bed drying Advanced Drying Technologies by Kudra, Tadeusz.; Mujumdar, A. S,

New York Marcel Dekker, Inc., 2001.

The invention also provides a process for preparing the Camphorsulfonate or a solvate thereof, characterised in that 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (Compound (I)), preferably dispersed or dissolved in a suitable solvent, is reacted with a suitable source of 10- camphorsulfonate ion; and optionally thereafter as required:

(i) forming a solvate thereof; (ii) recovering the Camphorsulfonate or solvate thereof ; or

(iii) further processing the Camphorsulfonate or solvate therof in a manufacturing process requiring or generating heat.

A suitable reaction solvent is an alkanol, for example propan-2-ol, or a hydrocarbon, such as toluene, a ketone, such as acetone, an ester, such as ethyl acetate, an ether such as tetrahydrofuran, a nitrile such as acetonitrile, or a halogenated hydrocarbon such as dichloromethane or water, or an organic acid such as acetic acid; or a mixture thereof.

Conveniently, the source of 10-camphorsulfonate ion is 10-camphorsulfonic acid.

The 10-camphorsulfonic acid is preferably added as a solid or in solution, for example in water or a lower alcohol such as methanol, ethanol, or propan-2-ol, or an ether such as tetrahydrofuran, or a mixture of solvents. An alternative source of 10-camphorsulfonate ion is provided by a suitably soluble base salt of 10-camphorsulfonic acid for example ammonium tartrate, or the 10-camphorsulfonic acid salt of an amine, for example ethylamine or diethylamine.

The concentration of Compound (I) is preferably in the range 2 to 25% weight/volume, more preferably in the range 5 to 20%. The concentration of 10- camphorsulfonic acid solutions are preferably in the range of 2 to 25% weight/volume. The reaction is usually carried out at ambient temperature or at an elevated temperature, for example at the reflux temperature of the solvent, although any convenient temperature that provides the required product may be employed.

As indicated above the Camphorsulfonate can exist as a solvate. Suitable solvates are pharmaceutically acceptable solvates, such as hydrates. A favoured solvate is a hydrate.

Solvates, such as hydrates, of the Camphorsulfonate may be prepared according to conventional procedures, for example by crystallising or recrystallising from a solvent which provides or contains the solvate moiety, or by exposing the Camphorsulfonate to the solvate moiety as a vapour. When the solvate is formed by crystallization methods the nature of the solvate is typically dictated by the solvent from which the Camphorsulfonate is crystallized. A Camphorsulfonate solvate is a one aspect of the present invention.

Recovery of the required compound generally comprises crystallisation from an appropriate solvent, conveniently the reaction solvent, usually assisted by cooling. For example, the Camphorsulfonate may be crystallised from an ester such as ethyl acetate. An improved yield of the salt may be obtained by evaporation of some or all of the solvent or by crystallisation at elevated temperature followed by controlled cooling, preferably in stages. Careful control of precipitation temperature and seeding may be used to improve the reproducability product form.

Suitable manufacturing processes requiring or generating heat include milling, heat-drying, especially a fluid-bed drying, hot melt processing or heat-sterilisation, such as autoclaving. Suitable manufacturing processes requiring or generating heat include milling, heat-drying, especially a fluid-bed drying or heat-sterilisation, such as autoclaving.

Crystallisation can also be initiated by seeding with crystals of the Camphorsulfonate or a solvate thereof but this is not essential.

Compound (I) is prepared according to known procedures, such as those disclosed in EP 0,306,228 and WO 94/05659. The disclosures of EP 0,306,228 and WO 94/05659 are incorporated herein by reference.

10-Camphorsulfonic acid is a commercially available compound. When used herein the term "T_onset" is generally determined by Differential Scanning Calorimetry and has a meaning generally understood in the art, as for example expressed in "Pharmaceutical Thermal Analysis, Techniques and Applications", Ford and Timmins, 1989 as "The temperature corresponding to the intersection of the pre- transition baseline with the extrapolated leading edge of the transition".

When used herein the term 'prophylaxis of conditions associated with diabetes mellitus' includes the treatment of conditions such as insulin resistance, impaired glucose tolerance, hyperinsulinaemia and gestational diabetes.

For the avoidance of doubt the term Camphorsulfonate can refer to a single stereoisomer of the salt or to a mixture of stereoisomers.

When used herein '10-camphorsulfonic acid' can refer to a single stereoisomer the acid or a mixture of stereoisomers of the acid.

Diabetes mellitus preferably means Type II diabetes mellitus.

Conditions associated with diabetes include hyperglycaemia and insulin resistance and obesity. Further conditions associated with diabetes include hypertension, cardiovascular disease, especially atherosclerosis, certain eating disorders, in particular the regulation of appetite and food intake in subjects suffering from disorders associated with under-eating, such as anorexia nervosa, and disorders associated with over-eating, such as obesity and anorexia bulimia. Additional conditions associated with diabetes include polycystic ovarian syndrome and steroid induced insulin resistance.

The complications of conditions associated with diabetes mellitus encompassed herein includes renal disease, especially renal disease associated with the development of Type II diabetes including diabetic nephropathy, glomerulonephritis, glomerular sclerosis, nephrotic syndrome, hypertensive nephrosclerosis and end stage renal disease. As mentioned above the compound of the invention has useful therapeutic properties: The present invention accordingly provides the Camphorsulfonate or a pharmaceutically acceptable solvate thereof for use as an active therapeutic substance.

More particularly, the present invention provides the Camphorsulfonate or a pharmaceutically acceptable solvate thereof for use in the treatment and/or prophylaxis of diabetes mellitus, conditions associated with diabetes mellitus and certain complications thereof.

The Camphorsulfonate or a pharmaceutically acceptable solvate thereof may be administered per se or, preferably, as a pharmaceutical composition also comprising a pharmaceutically acceptable carrier. Suitable methods for formulating the Camphorsulfonate or a pharmaceutically acceptable solvate thereof are generally those disclosed for Compound (I) in the above mentioned publications. Accordingly, the present invention also provides a pharmaceutical composition comprising the Camphorsulfonate or a pharmaceutically acceptable solvate thereof and a pharmaceutically acceptable carrier therefor.

The Camphorsulfonate or a pharmaceutically acceptable solvate thereof is normally administered in unit dosage form.

The active compound may be administered by any suitable route but usually by the oral or parenteral routes. For such use, the compound will normally be employed in the form of a pharmaceutical composition in association with a pharmaceutical carrier, diluent and/or excipient, although the exact form of the composition will naturally depend on the mode of administration.

Compositions are prepared by admixture and are suitably adapted for oral, parenteral or topical administration, and as such may be in the form of tablets, capsules, oral liquid preparations, powders, granules, lozenges, pastilles, reconstitutable powders, injectable and infusable solutions or suspensions, suppositories and transdermal devices. Orally administrable compositions are preferred, in particular shaped oral compositions, since they are more convenient for general use.

Tablets and capsules for oral administration are usually presented in a unit dose, and contain conventional excipients such as binding agents, fillers, diluents, tabletting agents, lubricants, disintegrants, colourants, flavourings, and wetting agents. The tablets may be coated according to well known methods in the art.

Suitable fillers for use include cellulose, mannitol, lactose and other similar agents. Suitable disintegrants include starch, polyvinylpyrrolidone and starch derivatives such as sodium starch glycollate. Suitable lubricants include, for example, magnesium stearate. Suitable pharmaceutically acceptable wetting agents include sodium lauryl sulphate.

Solid oral compositions may be prepared by conventional methods of blending, filling, tabletting or the like. Repeated blending operations may be used to distribute the active agent throughout those compositions employing large quantities of fillers. Such operations are, of course, conventional in the art. Oral liquid preparations may be in the form of, for example, aqueous or oily suspensions, solutions, emulsions, syrups, or elixirs, or may be presented as a dry product for reconstitution with water or other suitable vehicle before use. Such liquid preparations may contain conventional additives such as suspending agents, for example sorbitol, syrup, methyl cellulose, gelatin, hydroxyethylcellulose, carboxymethyl cellulose, aluminium stearate gel or hydrogenated edible fats, emulsifying agents, for example lecithin, sorbitan monooleate, or acacia; non-aqueous vehicles (which may include edible oils), for example, almond oil, fractionated coconut oil, oily esters such as esters of glycerine, propylene glycol, or ethyl alcohol; preservatives, for example methyl or propyl p-hydroxybenzoate or sorbic acid, and if desired conventional flavouring or colouring agents.

For parenteral administration, fluid unit dose forms are prepared containing a compound of the present invention and a sterile vehicle. The compound, depending on the vehicle and the concentration, can be either suspended or dissolved. Parenteral solutions are normally prepared by dissolving the active compound in a vehicle and filter sterilising before filling into a suitable vial or ampoule and sealing. Advantageously, adjuvants such as a local anaesthetic, preservatives and buffering agents are also dissolved in the vehicle. To enhance the stability, the composition can be frozen after filling into the vial and the water removed under vacuum.

Parenteral suspensions are prepared in substantially the same manner except that the active compound is suspended in the vehicle instead of being dissolved and sterilised by exposure to ethylene oxide before suspending in the sterile vehicle. Advantageously, a surfactant or wetting agent is included in the composition to facilitate uniform distribution of the active compound.

As is common practice, the compositions will usually be accompanied by written or printed directions for use in the medical treatment concerned.

The present invention further provides a method for the treatment and/or prophylaxis of diabetes mellitus, conditions associated with diabetes mellitus and certain complications thereof, in a human or non-human mammal which comprises administering an effective, non-toxic, amount of the Camphorsulfonate or a pharmaceutically acceptable solvate thereof to a human or non-human mammal in need thereof.

Conveniently, the active ingredient may be administered as a pharmaceutical composition hereinbefore defined, and this forms a particular aspect of the present invention.

In a further aspect the present invention provides the use of the Camphorsulfonate or a pharmaceutically acceptable solvate thereof for the manufacture of a medicament for the treatment and/or prophylaxis of diabetes mellitus, conditions associated with diabetes mellitus and certain complications thereof.

In the treatment and/or prophylaxis of diabetes mellitus, conditions associated with diabetes mellitus and certain complications thereof the Camphorsulfonate or a pharmaceutically acceptable solvate thereof may be taken in amounts so as to provide Compound (I) in suitable doses, such as those disclosed in EP 0,306,228, WO94/05659 or WO98/55122.

The unit dose compositions of the invention comprise the Camphorsulfonate or a pharmaceutically acceptable solvate thereof in an amount providing up to 12 mg, including 1-12 mg such as 2-12 mg of Compound (I), especially 2-4 mg, 4-8 mg or 8-12 mg of Compound (I), for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 mg of Compound (I). Thus in particular there is provided a pharmaceutical composition comprising the Camphorsulfonate or a pharmaceutically acceptable solvate thereof and a pharmaceutically acceptable carrier therefor, wherein the Camphorsulfonate or a pharmaceutically acceptable solvate thereof is present in an amount providing 1, 2, 4, 8, 12, 4 to 8 or 8 to 12 mg of Compound (I); such as 1 mg of Compound (I); such as 2 mg of Compound (I); such as 4 mg of Compound (I); such as 8 mg of Compound (I); such as 12 mg of Compound (I). The invention also provides a pharmaceutical composition comprising the

Camphorsulfonate or a pharmaceutically acceptable solvate thereof in combination with one or more other anti-diabetic agents and optionally a pharmaceutically acceptable carrier therefor.

The invention also provides a method for the treatment and/or prophylaxis of diabetes mellitus, conditions associated with diabetes mellitus and certain complications thereof, in a human or non-human mammal which comprises administering an effective, non-toxic, amount of the Camphorsulfonate or a pharmaceutically acceptable solvate thereof in combination with one or more other anti-diabetic agents.

In a further aspect the present invention provides the use of the Camphorsulfonate or a pharmaceutically acceptable solvate thereof in combination with one or more other anti-diabetic agents, for the manufacture of a medicament for the treatment and/or prophylaxis of diabetes mellitus, conditions associated with diabetes mellitus and certain complications thereof.

In the above mentioned treatments the administration of the Camphorsulfonate or a pharmaceutically acceptable solvate thereof and the other anti-diabetic agent or agents includes co-administration or sequential administration of the active agents.

Suitably in the above mentioned compositions, including unit doses, or treatments the Camphorsulfonate or a pharmaceutically acceptable solvate thereof is present in an amount providing up to 12 mg, including 1-12 mg, such as 2-12 mg of Compound (I), especially 2-4 mg, 4-8 mg or 8-12 mg of Compound (I), for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 mg of Compound (I) or 4 to 8 or 8 to 12 mg of Compound (I). Thus for example in the above mentioned compositions, including unit doses, or treatments the Camphorsulfonate or a pharmaceutically acceptable solvate thereof is present in an amount providing 1 mg of Compound (I); the Camphorsulfonate or a pharmaceutically acceptable solvate thereof is present in an amount providing 2 mg of Compound (I); the Camphorsulfonate or a pharmaceutically acceptable solvate thereof is present in an amount providing 3 mg of Compound (I); the Camphorsulfonate or a pharmaceutically acceptable solvate thereof is present in an amount providing 4 mg of Compound (I); or the Camphorsulfonate or a pharmaceutically acceptable solvate thereof is present in an amount providing 8 mg of Compound (I).

The other antidiabetic agents are suitably selected from biguanides, sulphonylureas and alpha glucosidase inhibitors. The other antidiabetic agent is suitably a biguanide. The other antidiabetic agent is suitably a sulphonylurea. The other antidiabetic agent is suitably a alpha glucosidase inhibitor. Suitable antidiabetic agents are those disclosed in WO98/57649, WO98/57634, WO98/57635, WO98/57636, WO99/03477, WO99/03476. The contents of the above mentioned publications are incorporated herein by reference as if set out in full herein.

No adverse toxicological effects are indicated in the above mentioned treatments for the compounds of the invention.

The following examples illustrate the invention but do not limit it in any way.

Example 1: 5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl] thiazolidine-2,4-dione ( 1 R)-(-)- 10-camphorsulfonate

A mixture of 5-[4-[2-(N-Methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4- dione (5.0 g) and tetrahydrofuran (50 ml) was stirred at 21°C until a clear solution was observed. A solution of (li?)-(-)- 10-camphorsulfonic acid (3.6 g) in tetrahydrofuran (20 ml) was added and the mixture stirred for 5 minutes. The solution was concentrated to approximately 20% of the initial volume, by evaporation under reduced pressure and was then diluted with ethyl acetate (75 ml). The mixture was stirred for 1 hour at 21°C before a further volume of ethyl acetate (25 ml) was added and stirring continued for a further 3 hours. The product was collected by filtration, washed with ethyl acetate (25 ml) and dried under vacuum at 40°C for 3 hours to give 5-[4-[2-(N-Methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (li?)-(-)-l 0-camphorsulfonate (6.0 g) as a white crystalline solid.

Example 2 : 5 - [4- [2-(N-methyl-N-(2-pyridyl)amino)ethoxy] benzyl] thiazolidine-2,4-dione (1 R)-(-)- 10-camphorsulfonate

5-[4-[2-(N-Methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (5.0 g) in ethyl acetate (100 ml) was heated at reflux for 2 hours until a clear solution was observed.

(lR)-(-)- 10-camphorsulfonic acid (3.25 g) was added, and the mixture stirred at reflux for 1 hour, then seeded with crystals of the product of Example 1 (10.0 mg). The mixture was cooled to 21°C, then stirred at 21°C until crystallisation was complete. The solid was collected by filtration, washed with ethyl acetate (100 ml) then dried under vacuum for

4.5 hours at 21°C to give 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (\R)-(-)-l 0-camphorsulfonate as a white crystalline solid.

Elemental Analysis

Found: C; 56.79 H; 5.95 N; 6.93

Theory: (C₂₈H₃₅N₃O₇S₂) C; 57.03 H; 5.98 N; 7.13

1H-NMR (d⁶-DMSO): consistent with 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (\R)-(-)- 10-camphorsulfonate containing ethyl acetate 2.1% by weight.

DSC (open pan, 10°C/min): T_onset = 153°C, T_peak = 158°C

Example 3: 5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl] thiazolidine-2,4-dione (li?)-(-)-10-camphorsulfonate

5-[4-[2-(N-Methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (15.0 g) in ethyl acetate (300 ml) was stirred and heated to reflux for 1 hour at which point a clear solution was observed. (\R)-(-)- 10-camphorsulfonic acid (9.75 g) was added, and the stirred mixture heated at reflux for 20 minutes before cooling to 21°C. Stirring was continued for 48 hours at 21°C, and the white solid collected by filtration, washed with ethyl acetate (150 ml) then dried in a dessicator for 56 hours to give 5-[4-[2-(N-methyl- N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (li?)-(-)-10-camphorsulfonate (22.2 g) as a white crystalline solid.

DSC (open pan, 10°C/min): T_onset = 154°C, T_peak = 159°C

Characterising data for the product of Example 2:

The infrared absorption spectrum of a mineral oil dispersion of the product was obtained using a Nicolet 710 FT-IR spectrometer at 2 cm"¹ resolution (Figure 1). Data were digitised at 1 cm^"1 intervals. Bands were observed at: 3111, 2954, 2922, 2853, 2779, 1735, 1695, 1644, 1627, 1585, 1544, 1514, 1483, 1461, 1416, 1392, 1376, 1331, 1313, 1283, 1267, 1237, 1209, 1200, 1180, 1169, 1151, 1068, 1040, 999, 968, 928, 910, 849, 838, 824, 787, 762, 740, 720, 665, 619, 602, 594, 584, 570, 535, 524, 511, 430 cm^"1.

The infrared spectrum of the solid product was recorded using Perkin-Elmer Spectrum One FT-IR spectrometer fitted with a universal ATR accessory. Bands were observed at: at 2956, 2776, 1733, 1694, 1645, 1626, 1544, 1514, 1484, 1416, 1392, 1330, 1235, 1209, 1147, 1036, 1000, 969, 928, 824, 788, 760, 719, 665 cm^"1.

The Raman spectrum of the product (Figure 2) was recorded with the sample in an NMR tube using a Nicolet 960 E.S.P. FT-Raman spectrometer, at 4 cm^"1 resolution with excitation from a Nd:N04 laser (1064 nm) with a power output of 400mW. Bands were observed 3107, 3069, 2956, 2919, 1743, 1696, 1612, 1586, 1545, 1457, 1443, 1417, 1390, 1332, 1299, 1269, 1240, 1207, 1185, 1127, 1068, 1036, 999, 959, 934, 851, 826, 790, 761, 740, 720, 686, 667, 638, 602, 570, 557, 537, 509, 473, 415, 328, 291, 161, 100 cm^"1.

The X-Ray Powder Diffractogram pattern of the product (Figure 3) was recorded using the following acquisition conditions: Tube anode: Cu, Generator tension: 40 kV, Generator current: 40 raA, Start angle: 2.0 °2Θ, End angle: 35.0 °2Θ, Step size: 0.02 °2Θ , Time per step: 2.5 seconds.Characteristic XRPD angles and relative intensities are recorded in Table 1.

Table 1

The solid-state NMR spectrum of the product (Figure 4) was recorded on a Bruker AMX360 instrument operating at 90.55 MHz: The solid was packed into a 4 mm zirconia MAS rotor fitted with a Kel-F cap and rotor spun at ca.10 kHz. The ¹³C MAS spectrum was acquired by cross-polarisation from Hartmann-Hahn matched protons (CP contact time 3 ms, repetition time 15 s) and protons were decoupled during acquisition using a two-pulse phase modulated (TPPM) composite sequence. Chemical shifts were externally referenced to the carboxylate signal of glycine at 176.4 ppm relative to TMS and were observed at: 18.5, 20.4, 23.5, 24.3, 27.5, 28.5, 35.4, 37.5, 39.9, 41.3, 42.5, 43.2, 44.8, 47.5, 48.7, 49.8, 52.3, 54.5, 58.5, 59.1, 61.8, 63.5, 64.9, 110.0, 111.7, 112.8, 113.6, 115.0, 117.0, 120.7, 128.8, 130.2, 132.8, 137.9, 141.9, 142.5, 152.8, 157.7, 158.5, 159.0, 171.7, 172.8, 176.2, 177.9, 215.2, 217.9, 219.0 ppm.

Properties of the (lR)-(-)-10-camphorsuIfonate, recorded for the product of Example 3

Solid State Stability of the (lR)-(-)-10-camphorsulfonate

The solid state stability of the drug substance was determined by storing approximately 1.0 g of the material in a glass bottle at i) 40°C / 75% Relative Humidity (RH), open exposure, for 1 month and b) at 50°C, closed, for 1 month. The material was assayed by HPLC for final content and degradation products in both cases. a) 40°C / 75% RH: No significant degradation observed (HPLC assay 101% initial). b) 50°C: No significant degradation observed (HPLC assay 96% initial).

Tonset of the (lR)-(-)-10-camphorsulfonate

The T_onset of the drug substance was determined by Differential Scanning Calorimetry using a Perkin-Elmer DSC7 apparatus. ^τonset (10°C/minute, closed pan): 156.7°C

Melting Range of the (lR)-(-)-10-camphorsulfonate

The melting range of the Sulfate was determined according to the method described in the U.S. Pharmacopoeia, USP 23, 1995, <741> "Melting range or temperature, Procedure for Class la", using a Buchi 545 melting point instrument. Melting range: 154.8 -155.6°C

Example 4: 5-[4-[2-(N-methyI-N-(2-pyridyl)amino)ethoxy]benzyl] thiazolidine-2,4-dione (lS)-(+)-10-camphorsuIfonate

A solution of (lS)-(+)-10-camphorsulfonic acid (2.6 g) in tetrahydrofuran (20 ml) was added to a stirred solution of 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (4.0 g) in tetrahydrofuran (60 ml) at 21°C. The reaction mixture was stirred at 21°C for 16 hours. The solvent was evaporated and the product dried under vacuum at 50°C. A portion of the product (1.0 g) was mixed with ethyl acetate (5 ml) and the mixture was stirred for 26 hours at 21 °C. The product was collected by filtration, washed with ethyl acetate and dried under vacuum to give 5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (lS)- (+)- 10-camphorsulfonate as a white crystalline solid.

Example 5: 5-[4-[2-(N-methyI-N-(2-pyridyl)amino)ethoxy]benzyl] thiazolidine-2,4-dione (lS)-(+)-10-camphorsuIfonate

A mixture of (15)-(+)- 10-camphorsulfonic acid (3.25 g) and 5-[4-[2-(N-methyl- N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (5.0 g) in ethyl acetate (170 ml) was stirred and heated to reflux to give a clear solution. The mixture was cooled to 21°C and the solvent evaporated under reduced pressure. Ethyl acetate (50 ml) was added and the mixture stirred for 3 hours at 45°C and then cooled to 21°C. The mixture was sonicated for 30 minutes and then stirred at 21°C until crystallisation was complete. The product was collected by filtration, washed with ethyl acetate (40 ml) and dried under vacuum for 3 hours at 21°C to give 5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy] benzyl]thiazolidine-2,4-dione (lS)-(+)-10-camphorsulfonate (7.2 g) as a white crystalline solid.

Example 6: 5-[4-[2-(N-methyl-N-(2-pyridyI)amino)ethoxy]benzyl] thiazolidine-2,4-dione (lS)-(+)-10-camphorsulfonate

(lS)-(+)-10-Camphorsulfonic acid (13.2 g) was added to a stirred solution of 5-[4- [2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (20.0 g) in ethyl acetate (450 ml) at reflux. The reaction mixture was stirred for 30 minutes at reflux, then cooled to 50°C. The temperature was maintained at 50°C until the onset of crystallisation was observed and was then cooled to 21°C over a period of approximately 1 hour. The product was collected by filtration, washed with ethyl acetate (100 ml) and dried under vacuum for 5 hours at 21 °C to afford 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2, 4-dione (lS)-(+)-10-camphorsulfonate (31.9 g) as a white crystalline solid. 1H-NMR (d⁶-DMSO): consistent with 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (lS)-(+)-10-camphorsulfonate.

Elemental Analysis: Found: C; 56.60 H; 5.92 N; 7.00

Theory: (C₂₈H₃₅N₃O₇S₂) C; 57.03 H; 5.98 N; 7.13

DSC (open pan, 10°C/min): T_onset = 151°C, T_peak = 156°C

Characterising data recorded for the product of Example 6:

The infrared absorption spectrum of a mineral oil dispersion of the product was obtained using a Nicolet 710 FT-IR spectrometer at 2 cm^-1 resolution (Figure 5). Data were digitised at 1 cm^~l intervals. Bands were observed at: 3423, 3111, 2922, 2853, 2778, 1734, 1696, 1644, 1626, 1544, 1514, 1462, 1416, 1376, 1330, 1236, 1209, 1150, 1040, 1000, 968, 824, 762, 720, 664, 618, 602, 584, 570, 524, 509 cm^"1.

The infrared spectrum of the solid product was recorded using Perkin-Elmer Spectrum One FT-IR spectrometer fitted with a universal ATR accessory. Bands were observed at: 2955, 2776, 1733, 1694, 1644, 1625, 1543, 1513, 1484, 1416, 1392, 1330, 1235, 1209, 1147, 1036, 1000, 969, 927, 824, 787, 761, 719, 664 cm^"1. The Raman spectrum of the product (Figure 6) was recorded with the sample in an NMR tube using a Nicolet 960 E.S.P. FT-Raman spectrometer, at 4 cm"l resolution with excitation from a Nd:V04 laser (1064 nm) with a power output of 400mW. Bands were observed at 3108, 3070, 3037, 2955, 2920, 1744, 1613, 1545, 1458, 1444, 1417, 1391, 1332, 1299, 1270, 1241, 1207, 1186, 1068, 1037, 1000, 960, 933, 852, 830, 790, 761, 720, 686, 668, 639, 603, 571, 557, 538, 510, 473, 394, 329, 296 cm^"1.

The X-Ray Powder Diffractogram pattern of the product (Figure 7) was recorded using the following acquisition conditions: Tube anode: Cu, Generator tension: 40 kN, Generator current: 40 mA, Start angle: 2.0 °2Θ, End angle: 35.0 °2Θ, Step size: 0.02 °2Θ , Time per step: 2.5 seconds. Characteristic XRPD angles and relative intensities are recorded in Table 2.

Table 2

The solid-state NMR spectrum of the product (Figure 8) was recorded on a Bruker AMX360 instrument operating at 90.55 MHz: The solid was packed into a 4 mm zirconia MAS rotor fitted with a Kel-F cap and rotor spun at ca.10 kHz. The ^l3C MAS spectrum was acquired by cross-polarisation from Hartmann-Hahn matched protons (CP contact time 3 ms, repetition time 15 s) and protons were decoupled during acquisition using a two-pulse phase modulated (TPPM) composite sequence. Chemical shifts were externally referenced to the carboxylate signal of glycine at 176.4 ppm relative to TMS and were observed at: 18.4, 20.5, 23.5, 24.3, 27.4, 28.5, 35.3, 37.5, 39.8, 41.3, 42.6, 43.3, 44.7, 47.5, 48.7, 49.8, 52.3, 54.5, 58.6, 59.0, 61.8, 63.4, 64.9, 109.9, 111.7, 112.8, 113.5, 115.1, 117.0, 120.6, 128.6, 130.3, 132.8, 137.9, 141.9, 142.7, 152.8, 157.7, 158.5, 159.1, 171.7, 172.8, 176.2, 177.8, 215.4, 218.9 ppm.

Properties of the (15)-(+)-10-camphorsulfonate, recorded for the product of

Example 6 Solid State Stability of the (lS)-(+)-10-camphorsulfonate

The solid state stability of the drug substance was determined by storing approximately

1.0 g of the material in a glass bottle at i) 40°C / 75% Relative Humidity (RH), open exposure, for 1 month and b) at 50°C, closed, for 1 month. The material was assayed by HPLC for final content and degradation products in both cases. a) 40°C / 75% RH: No significant degradation observed (HPLC assay 102% initial). b) 50°C: No significant degradation observed (HPLC assay 97% initial).

T_onset of the (15)-(+)-10-camphorsulfonate

The T_onset of the drug substance was determined by Differential Scanning Calorimetry using a Perkin-Elmer DSC7 apparatus. ^τonset (10°C/minute, closed pan): 151.5°C

Melting Range of the (15)-(+)-10-camphorsulfonate

The melting range of the Sulfate was determined according to the method described in the U.S. Pharmacopoeia, USP 23, 1995, <741> "Melting range or temperature, Procedure for Class la", using a Buchi 545 melting point instrument. Melting range: 153.7 - 154.9°C

Example 7: 5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl] thiazolidine-2,4-dione (+)- 10-camphorsulfonate

5-[4-[2-(N-Methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (5.0 g) in ethyl acetate (100 ml) was heated at reflux for 1.5 hours when a clear solution was observed. (±)-lO-Camphorsulfonic acid (3.25 g) was added and the mixture stirred at reflux for 1 hour, followed by 3 hours at 50°C and then 16 hours at 21°C. The solid was collected by filtration, washed with ethyl acetate (100 ml) then dried under vacuum for 75 minutes at 21°C to give 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (±)-lO-camphorsulfonate (7.9 g) as a white crystalline solid.

1H-NMR (d⁶-DMSO): consistent with 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (+)- 10-camphorsulfonate.

Elemental Analysis

Found: C; 56.74 H; 5.93 N; 7.00

Theory: (C₂₈H₃₅N₃O₇S₂) C; 57.03 H; 5.98 N; 7.13

DSC (open pan, 10°C/min): T_onset = 170°C, T_peak = 174°C

Example 8: 5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl] thiazolidine-2,4-dione (±)- 10-camphorsulfonate

5-[4-[2-(N-Methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (15.0 g) in ethyl acetate (300 ml) was stirred and heated to reflux for 1 hour at which point a clear solution was observed. (+)-10-Camphorsulfonic acid (9.75 g) was added, the mixture heated at reflux for 20 minutes then cooled to 21°C. Stirring was continued for 24 hours at 21°C. The white solid was collected by filtration, washed with ethyl acetate (200 ml) and dried under vacuum at 21°C for 1 hour to give 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (±)-lO-camphorsulfonate (24.2 g) as a white crystalline solid.

DSC (open pan, 10°C/min): T_onSet = 168°C, T_peak = 172°C

Characterising data recorded for the product of Example 7:

The infrared absorption spectrum of a mineral oil dispersion of the product was obtained using a Nicolet 710 FT-IR spectrometer at 2 cm^-1 resolution (Figure 9). Data were digitised at 1 cm^"1 intervals. Bands were observed at: 3111, 2954, 2923, 2854, 2778, 1734, 1695, 1645, 1626, 1586, 1544, 1514, 1484, 1459, 1415, 1392, 1385, 1376, 1331, 1313, 1282, 1267, 1237, 1209, 1201, 1179, 1170, 1149, 1128, 1069, 1042, 1000, 968,

939, 928, 910, 850, 839, 825, 787, 762, 740, 720, 665, 619, 601, 594, 584, 570, 558, 536, 524, 511, 472, 430 cm^"1.

The infrared spectrum of the solid product was recorded using Perkin-Elmer Spectrum One FT-IR spectrometer fitted with a universal ATR accessory. Bands were observed at: 2956, 2776, 1733, 1693, 1645, 1625, 1543, 1513, 1484, 1415, 1392, 1330, 1312, 1235, 1209, 1169, 1146, 1070, 1041, 1000, 969, 928, 824, 788, 758, 718, 664 cm^"1. The Raman spectrum of the product (Figure 10) was recorded with the sample in an NMR tube using a Nicolet 960 E.S.P. FT-Raman spectrometer, at 4 cm^"1 resolution with excitation from a Nd:V04 laser (1064 nm) with a power output of 400mW. Bands were observed at 3107, 3070, 3037, 2957, 2918, 1743, 1696, 1612, 1586, 1545, 1458, 1443, 1416, 1390, 1332, 1298, 1269, 1241, 1207, 1185, 1068, 1036, 1000, 959, 933, 851, 828, 789, 761, 719, 686, 667, 639, 602, 585, 570, 556, 537, 509, 473, 393, 329, 295, 103 cm^'1.

The X-Ray Powder Diffractogram pattern of the product (Figure 11) was recorded using the following acquisition conditions: Tube anode: Cu, Generator tension: 40 kV, Generator current: 40 mA, Start angle: 2.0 °2Θ, End angle: 35.0 °2Θ, Step size: 0.02 °2Θ , Time per step: 2.5 seconds.Characteristic XRPD angles and relative intensities are recorded in Table 3.

Table 3

The solid-state NMR spectrum of the product (Figure 12) was recorded on a Bruker AMX360 instrument operating at 90.55 MHz: The solid was packed into a 4 mm zirconia MAS rotor fitted with a Kel-F cap and rotor spun at ca.10 kHz. The ¹³C MAS spectrum was acquired by cross-polarisation from Hartmann-Hahn matched protons (CP contact time 3 ms, repetition time 15 s) and protons were decoupled during acquisition using a two-pulse phase modulated (TPPM) composite sequence. Chemical shifts were externally referenced to the carboxylate signal of glycine at 176.4 ppm relative to TMS and were observed at: 20.3, 24.2, 28.5, 35.3, 37.8, 40.0, 42.2, 43.1, 45.0, 46.5, 48.8, 52.5, 54.4, 59.1, 61.9, 63.1, 112.2, 117.0, 130.2, 133.1, 138.1, 142.4, 152.7, 157.9, 171.9, 176.3, 219.1 ppm.

Properties of the (±)-lO-camphorsulfonate, recorded for the product of Example 8 Solid State Stability of the (±)-lO-camphorsulfonate The solid state stability of the drug substance was determined by storing approximately

1.0 g of the material in a glass bottle at i) 40°C / 75% Relative Humidity (RH), open exposure, for 1 month and b) at 50°C, closed, for 1 month. The material was assayed by HPLC for final content and degradation products in both cases. a) 40°C / 75% RH: No significant degradation observed (HPLC assay 102% initial). b) 50°C: No significant degradation observed (HPLC assay 96% initial).

T_onset of the (±)-10-camphorsulfonate

The T_onset of the drug substance was determined by Differential Scanning Calorimetry using a Perkin-Elmer DSC7 apparatus. ^τonset (10°C/minute, closed pan): 166.9°C

Melting Range of the (±)-10-camphorsulfonate

The melting range of the Sulfate was determined according to the method described in the U.S. Pharmacopoeia, USP 23, 1995, <741> "Melting range or temperature, Procedure for Class la", using a Buchi 545 melting point instrument. Melting range: 168.3 - 169.7°C

Claims

1. A 5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione 10-camphorsulfonic acid salt (the Camphorsulfonate).

2. A salt according to claim 1 being, 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione ( 1 R)-(-)- 10-camphorsulfonate salt (the (li?)-(-)-10-Camphorsulfonate).

3. A salt according to claim 1, being 15-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (lS)-(+)-l 0-camphorsulfonate salt (the ( 1 S)-(+)- 10-Camphorsulfonate).

4. A salt according to claim 1, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (+)- 10-camphorsulfonate salt (the (+)- 10-Camphorsulfonate).

5. A salt according to claim 2, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione ( 1 R)-(-)- 10-camphorsulfonate salt (the (1 /?)-(-)- 10-Camphorsulfonate) characterised by an infrared spectrum substantially in accordance with Figure 1.

6. A salt according to claims 2 or 5, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione 1 R)-(-)- 10-camphorsulfonate salt, characterised by a Raman spectrum substantially in accordance with Figure 2.

7. A salt according to claims 2, 5 or 6, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione li?)-(-)-l O-camphorsulfonate salt, characterised by an X-Ray powder diffraction pattern (XRPD) substantially in accordance with Table 1 or Figure 3.

8. A salt according to any one of claims 2 or 5 to 7, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione li?)-(-)-l O-camphorsulfonate salt, characterised by a Solid State ¹³C NMR spectrum substantially in accordance with Figure 4.

9. A salt according to any one of claims 2 or 5 to 8, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione 1 /?)-(-)- 1 O-camphorsulfonate salt, characterised by:

(i) an infrared spectrum substantially in accordance with Figure 1 ; and (ii) a Raman spectrum substantially in accordance with Figure 2; and

1 or Figure 3; and

(iv) a Solid State ¹³C NMR spectrum substantially in accordance with Figure 4.

10. A salt according to claim 3, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (lS)-(+)-10-camphorsulfonate.

11. A salt according to claim 3 or 10, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (15)-(+)-l 0-camphorsulfonate salt, characterised by an infrared spectrum substantially in accordance with Figure 5.

12. A salt according to any one of claims 3, 10 or 11, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (lS)-(+)-10-camphorsulfonate salt, characterised by a Raman spectrum substantially in accordance with Figure 6.

13. A salt according to any one of claims 3 or 10 to 12, being 5-[4-[2-(N-methyl-N- (2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione ( 1 S)-(+)- 10-camphorsulfonate salt, characterised by an X-Ray powder diffraction pattern (XRPD) substantially in accordance with Table 2 or Figure 7.

14. A salt according to any one of claims 3 or 10 to 13, being 5-[4-[2-(N-methyl-N- (2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione ( 1 S)-(+)- 10-camphorsulfonate salt, characterised by a Solid State C NMR spectrum substantially in accordance with Figure 8.

15. A salt according to any one of claims 3 or 10 to 14, being 5-[4-[2-(N-methyl-N- (2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (lS)-(+)-10-camphorsulfonate salt, characterised by:

(i) an infrared spectrum substantially in accordance with Figure 5; and (ii) a Raman spectrum substantially in accordance with Figure 6; and

(iii) an X-Ray powder diffraction pattern (XRPD) substantially in accordance with Table 2 or Figure 7; and

(iv) a Solid State ¹³C NMR spectrum substantially in accordance with Figure 8.

16. A salt according to claim 4, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (±)- 1 O-camphorsulfonate.

17. A salt according to claim 4 or 16, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (±)- 1 O-camphorsulfonate salt, characterised by an infrared spectrum substantially in accordance with Figure 9.

18. A salt according to any one of claims 4, 16 or 17, being 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (±)-l O-camphorsulfonate salt, characterised by a Raman spectrum substantially in accordance with Figure 10.

19. A salt according to any one of claims 4 or 16 to 18, being 5-[4-[2-(N-methyl-N- (2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (±)- 10-camphorsulfonate salt, characterised by an X-Ray powder diffraction pattern (XRPD) substantially in accordance with Table 3 or Figure 11.

20. A salt according to any one of claims 4 or 16 to 19, being 5-[4-[2-(N-methyl-N- (2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (±)- 10-camphorsulfonate salt, characterised by a Solid State C NMR spectrum substantially in accordance with Figure 12.

21. A salt according to any one of claims 4 or 16 to 20, being 5-[4-[2-(N-methyl-N- (2-pyridyl)amino)ethoxyjbenzyl]thiazolidine-2,4-dione (+)- 10-camphorsulfonate salt, characterised by:

(i) an infrared spectrum substantially in accordance with Figure 9; and

(ii) a Raman spectrum substantially in accordance with Figure 10; and

3 or Figure 11 ; and (iv) a Solid State ¹³C NMR spectrum substantially in accordance with Figure 12.

22. A compound according to any one of claims 1 to 21, or a solvate thereof, in isolated form.

23. A compound according to any one of claims 1 to 22, or a solvate thereof, in substantially pure form.

24. A compound according to any one of claims 1 to 23, or a solvate thereof, in crystalline form.

25. A compound according to any one of claims 1 to 24, or a solvate thereof, in a pharmaceutically acceptable solid dosage form.

26. A compound according to any one of claims 1 to 25, or a solvate thereof, in a bulk form capable of pharmaceutical processing in manufacturing processes which require or generate heat.

27 A compound according to claim 26, or a solvate thereof, in a milled form, in a heat-dried form, in a hot melt processed form; in a heat-sterilised form.

28 A compound according to any one of claims 26 or 27, or a solvate thereof, in a milled form.

29. A process for preparing the Camphorsulfonate or a solvate thereof, characterised in that 5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (Compound (I)), preferably dispersed or dissolved in a suitable solvent, is reacted with a suitable source of 10-camphorsulfonate ion; and optionally thereafter as required: (i) forming a solvate thereof;

(ii) recovering the Camphorsulfonate or solvate thereof ; or

30. A pharmaceutical composition comprising 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione 10-camphorsulfonic acid salt (the Camphorsulfonate) or a pharmaceutically acceptable solvate thereof, according to claim 1, and a pharmaceutically acceptable carrier therefor.

31. A pharmaceutical composition comprising the 5-[4-[2-(N-methyl-N-(2- pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione 10-camphorsulfonic acid salt (the Camphorsulfonate) or a pharmaceutically acceptable solvate thereof, according to claim 1 , in combination with one or more other anti-diabetic agents and optionally a pharmaceutically acceptable carrier therefor.

32. A pharmaceutical composition according to claim 30 or claim 31 , wherein 5-[4- [2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione 10- camphorsulfonic acid salt (the Camphorsulfonate) or the pharmaceutically acceptable solvate thereof, is present in an amount providing 1, 2, 4, 8, 12, 4 to 8 or 8 to 12 mg of 5-[4-[2-(N-methyl-N-(2-pyridyl)amino) ethoxy]benzyl]thiazolidine-2,4-dione (Compound (I)).

33. A compound5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine- 2,4-dione 10-camphorsulfonic acid salt (the Camphorsulfonate), or a pharmaceutically acceptable solvate thereof, according to claim 1, for use as an active therapeutic substance.

34. A compound5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine- 2,4-dione 10-camphorsulfonic acid salt (the Camphorsulfonate), or a pharmaceutically acceptable solvate thereof, for use in the treatment and/or prophylaxis of diabetes mellitus, conditions associated with diabetes mellitus and certain complications thereof.

35. A use of5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4- dione 10-camphorsulfonic acid salt (the Camphorsulfonate), or a pharmaceutically acceptable solvate thereof, according to claim 1, for the manufacture of a medicament for the treatment and/or prophylaxis of diabetes mellitus, conditions associated with diabetes mellitus and certain complications thereof.

36. A method for the treatment and/or prophylaxis of diabetes mellitus, conditions associated with diabetes mellitus and certain complications thereof, in a human or non-human mammal which comprises administering an effective, non-toxic, amount of 5- [4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione 10- camphorsulfonic acid salt (the Camphorsulfonate), or a pharmaceutically acceptable solvate thereof, according to claim 1 , to a human or non-human mammal in need thereof.