Novel calcium salt polymorphs as Anti-Inflammatory, Immunomodulatory and Anti-Proliferatory Agents

Abstract

Subject matter of the present invention is a white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof with a molar ratio of a compound according to formula I or a solvate and/or a hydrate thereof to calcium which is 20.3.

Subject matter of the present invention is in particular a compound according to formula I or a solvate and/or a hydrate thereof which is characterized by an X-ray powder diffraction pattern having characteristic peaks expressed in degrees 2theta at 0.2 of the values shown below: 2 theta=5.91, 9.64, 16.78, 17.81, 19.81, 25.41 In particular the invention refers to new polymorphs of calcium salts of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof which inhibits dihydroorotate dehydrogenase (DHODH), a process for their manufacture, pharmaceutical compositions containing them and to their use for the treatment and prevention of diseases, in particular their use in diseases where there is an advantage in inhibiting dihydroorotate dehydrogenase (DHODH).

Claims

1. A white crystalline polymorph A of the Ca salt of he compound according to formula I or a solvate and/or a hydrate thereof ##STR00003## with a molar ratio of said compound according to formula Ito calcium 20.3 to 1.

2. The white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof according to claim 1 which is characterized by an X-ray powder diffraction pattern having characteristic peaks expressed in degrees 2theta at 0.2 of the values shown below: 2 theta=5.91, 9.64, 16.78, 17.81, 19.81, 25.41.

3. The white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof according to claim 1, having characteristic peaks of 2theta at 0.2 of the values shown below: TABLE-US-00005 Angle d value 2-Theta Angstrom Intensity 5.91 14.95 vs 6.83 12.93 vw 9.64 9.17 w 11.33 7.80 w 11.82 7.48 w 12.98 6.81 vw 13.70 6.46 vw 14.27 6.20 vw 15.04 5.89 w 15.44 5.73 vw 16.78 5.28 s 17.81 4.98 m 18.25 4.86 w 18.58 4.77 vw 19.39 4.57 w 19.81 4.48 w 20.53 4.32 vw 21.26 4.18 vw 22.63 3.93 vw 23.16 3.84 vw 23.96 3.71 w 24.73 3.60 vw 25.41 3.50 s 26.12 3.41 w 26.44 3.37 w 27.25 3.27 w 27.55 3.24 w 28.45 3.13 w 28.91 3.09 vw 29.29 3.05 w 29.89 2.99 w 30.77 2.90 w 31.22 2.86 vw 31.60 2.83 w 32.13 2.78 w 33.25 2.69 vw 33.98 2.64 w 34.48 2.60 w 35.12 2.55 vw.

4. The white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof according to claim 1, characterized by the x-ray powder diffraction pattern shown in FIG. 1. FIG. 1.

5. The white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof according to which claim 1, is characterized by an FT Raman absorption spectrum having the following characteristic peaks expressed in cm.sup.1 1664, 1624, 1617, 1532, 1449, 1338 the spectrum is shown in FIG. 2. FIG. 2.

6. The white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof according to claim 1, which is characterized by an IR absorption spectrum having characteristic peaks expressed in cm.sup.1 1980, 1659, 1584, 1335, 1145, the spectrum is shown in FIG. 3a showing a complete region of FIG. 3b showing a fingerprint region. FIG. 3a FIG. 3b.

7. The white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof according to claim 1, which is characterized by an .sup.1H-NMR spectrum having characteristic peaks expressed in ppm, 15.2, 8.3, 7.6, 7.5, 7.4, 7.2, 6.8, 3.8, 2.7, 1.6, or wherein the spectrum is shown in FIG. 4. FIG. 4.

8. The white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof according to claim 1, which is a hydrate with a molar ratio of a compound according to formula I to water of about 1:1

9. The pharmaceutical formulation comprising a white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof according to claim 1 and a pharmaceutically acceptable excipient.

10. A pharmaceutical formulation according to claim 9 having a THF content of less than 720 ppm.

11. (canceled)

12. A method for treating a disease selected from the group consisting of rheumatism, acute immunological disorders, autoimmune diseases, diseases caused by malignant cell proliferation, inflammatory diseases, diseases that are caused by protozoal infestations in humans and animals, diseases that are caused by viral infections and Pneumocystis carinii, fibrosis, uveitis, rhinitis, asthma and athropathy, comprising administering to a subject in need thereof an effective amount of the white crystalline polymorph A of the Ca sail of a compound according to formula I or a solvate and/or a hydrate thereof according to claim 1.

13. A method for treating a disease selected from the group consisting of graft versus host and host versus graft reactions, rheumatoid arthritis, multiple sclerosis, amyotrophic lateral sclerosis, lupus erythematosus, inflammatory bowel disease, and psoriasis, comprising administering to a subject in need thereof an effective amount of the white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof according to claim 1.

14. A process for the manufacture of a white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof as defined in claim 1, which process comprises the steps of Providing a Ca-Vidofludimus or a solvate and/or a hydrate thereof, preferably a crystalline polymorph of the Ca salt of vidofludimus or a solvate and/or a hydrate thereof, washing the calcium salt of Calcium-vidofludimus or a solvate and/or a hydrate thereof with the an aprotic organic solvent, and slurring the isolated Calcium-vidofludimus or a solvate and/or a hydrate thereof obtained in an alcoholic solvent and adding water to the slurry.

15. A process for the manufacture of a white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof as defined in claim 1, which process comprises the steps of a) adding to a mixture of calcium hydroxide and free acid of a compound according to formula I or a solvate and/or a hydrate thereof an organic solvent and water b) stirring the suspension obtained in step a) until a solution is obtained, c) at least partially evaporating said organic solvent and water to obtain a suspension of the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof d) adding an aprotic organic solvent, fully mixable with water to said suspension of the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof obtained in step c) e) stirring the suspension obtained in step d), f) recovering the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof from the mixture obtained in step e), and g) washing the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof obtained in step f) with the aprotic organic solvent mentioned in step d), h) slurring the isolated calcium salt a compound according to formula I or a solvate and/or a hydrate thereof obtained in step g) in an alcoholic solvent at 15-80 C., i) adding water to the slurry obtained in step h) at 15-85 C. j) recovering the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof from the mixture obtained in step e), and k) washing the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof obtained in step j) with the aprotic organic solvent mentioned in step d).

16. A process for the manufacture of a crystalline polymorph according to claim 15 wherein after step g) and step k) a drying step is added, and optionally subsequently a milling step and optionally subsequently a recrystallization step is added.

17. A process for the manufacture of a crystalline polymorph according to claim 15 wherein after step b) and before step c) the solution is filtered and then the filter is washed with said organic solvent.

18. A process for the manufacture of a crystalline polymorph according to claim 15 wherein the suspension of step a) is heated to 25-30 C.

19. A process for the manufacture of a crystalline polymorph according to claim 15 wherein the suspension of step e) is heated to 15-25 C.

20. A process for the manufacture of a crystalline polymorph according to claim 14 wherein said organic solvent is selected from the group consisting of DMF, DMSO, NMP, THF, Acetone, Dioxane, 2-Methyl-THF and (Methanol/CH2Cl2 (1:3).

21. (canceled)

22. A white crystalline polymorph A of the Ca salt of a compound according to formula I or a solvate and/or a hydrate thereof with a molar ratio of a compound according to formula I to calcium of 20.3 to 1 obtainable by a process according to claim 14.

Description

FIGURE DESCRIPTION

[0108] FIG. 1: PXRD of Polymorph A of Ca vidofludimus

[0109] FIG. 2: Raman spectrum of Polymorph A of Ca vidofludimus

[0110] FIG. 3a: IR spectrum of Polymorph A of Ca vidofludimus, complete region.

[0111] FIG. 3b: IR spectrum of Polymorph A of Ca vidofludimus, fingerprint region.

[0112] FIG. 4: .sup.1H-NMR spectrum of Polymorph A of Ca vidofludimus.

[0113] FIG. 5: PXRD of Polymorph C of the Ca salt of a compound according to formula I

[0114] FIG. 6 PXRD of Polymorph B of the Ca salt of a compound according to formula I

EXAMPLES

Example 1

[0115] The compounds of formula (I) may be obtained via various methods, including the method described in JP-A-50-121428. In particular the two following methods of synthesis are used.

[0116] Method 1: In a first step the cycloalkene-1,2-dicarboxic acids can be obtained from the corresponding ,-dibromo alkanedicarboxylic acids as described by R. N. Mc Donald and R. R. Reitz, J. Org. Chem. 37, (1972) 2418-2422. Cyclopentene-1,2-dicarboxylic acid can also be obtained in large amounts from pimelic acid [D. C. Owsley and J. J. Bloomfield, Org. Prep. Proc. Int. 3, (1971) 61-70; R. Willstatter, J. Chem. Soc. (1926), 655-663].

[0117] Dicarboxylic acids substituted in or on the ring system can be synthesized in general via the cyanhydrine synthesis [Shwu-Jian Lee et. al., Bull. Inst. Chem. Academia Sinica Number 40, (1993), 1-10 or B. R. Baker at al., J. Org. Chem. 13, 1948, 123-133; and B. R. Baker at al., J. Org. Chem. 12, 1947, 328-332; L. A. Paquette et. al., J. Am. Chem. Soc. 97, (1975), 6124-6134].

[0118] The dicarboxylic acids can then be converted into the corresponding acid anhydrides by reacting them with acetic acid anhydride [P. Singh and S. M. Weinreb, Tetrahedron 32, (1976), 2379-2380].

[0119] Other methods for preparing different acid anhydrides of formula (II) are described in V. A. Montero at al., J. Org. Chem. 54, (1989), 3664-3667; P. ten Haken, J. Heterocycl. Chem. 7, (1970), 1211-1213; K. Alder, H. Holzrichter, J. Lieb. Annalen d. Chem. 524, (1936), 145-180; K. Alder, E. Windemuth, J. Lieb. Annalen d. Chem. 543, (1940), 56-78; and W. Flaig, J. Lieb. Annalen d. Chem. 568, (1950), 1-33.

[0120] These anhydrides may then be reacted with the corresponding amines to the desired amides of formula (I). This reaction can be carried out either by use of the reaction conditions as described in J. V. de Julian Ortiz et al., J. Med. Chem. 42, (1999), 3308 (designated route A in Example 1) or by use of 4-dimethylamino pyridine (designated route B in Example 1).

[0121] Method 2: The amides of formula (I) can also be synthesized by reacting an amine of the formula (IV) with an arylboronic-acid of the general formula (V) [M. P. Winters, Tetrahedron Lett., 39, (1998), 2933-2936].

[0122] Biarylaniline can be synthesized in general via the palladium coupling [G. W. Kabalka et al., Chem. Commun., (2001), 775; A. Demeter, Tetrahedron Lett. 38; (1997), 5219-5222; V. Snieckus, Chem. Commun. 22, (1999), 2259-2260].

[0123] Method 3: The amides of formula (I) can also be synthesized by reacting an halogen derivative of the formula (VI) with an arylboronic acid of the general formula (VII) [N. E. Leadbeater, S. M. Resouly, Tetrahedron, 55, 1999, 11889-11894].

Example 2

Experimental/Instrument Settings

[0124] .sup.1H-NMR: .sup.1H-NMR spectra were recorded using a Bruker DPX300 spectrometer with a proton frequency of 300.13 MHz, a 30 excitation pulse, and a recycle delay of 1 s. 16 scans were accumulated, D2O; MeOD or d6-DMSO was used as the solvent.

[0125] DSC: Differential scanning calorimetry was carried out with a Perkin Elmer DSC-7 instrument (closed gold sample pan under N.sub.2 atmosphere). The sample are heated up to the melting point at a rate of 10 K/min), then cooled down (cooling rate 200 K/min) and afterwards heated up again at a rate of 10 K/min.

[0126] DVS (SMS): Surface Measurement Systems Ltd. DVS-1 water vapour sorption analyzer. The sample is placed on a platinum sample pan and allowed to equilibrate at a given relative humidity (r.h.), usually 50% r.h. Then, a pre-defined humidity program was started with a scanning rate of 5% r.h. change per hour. First step: from 50% r.h. to 0% r.h. (in case of a possibly hydrate as starting material 50 to 95% r.h.), second step: from 0% to 95% r.h. (in case of a possibly hydrate as starting material 95 to 0% r.h.)

[0127] FT-Raman spectroscopy: FT-Raman spectra were recorded on a Bruker RFS 100 FT-Raman system with a near infrared Nd:YAG laser operating at 1064 nm and a liquid nitrogen-cooled germanium detector. For each sample, a minimum of 64 scans with a resolution of 2 cm.sup.1 were accumulated. 300 mW nominal laser power was used. The FT-Raman data are shown in the region between 3500 to 100 cm.sup.1. Below 100 cm.sup.1 the data are unreliable due to the Rayleigh filter cut-off.

[0128] Optical Microscopy: Leitz Orthoplan 110680 microscope equipped with a Leica DFC280 camera and IM50 v.5 image-capturing software. Images were recorded with or without crossed polarizers and with 4, 10, or 25 magnification.

[0129] Powder X-ray diffraction: Bruker D8; Copper K.sub.a radiation, 40 kV/40 mA; LynxEye detector, 0.02 2 step size, 37 s step time. Sample preparation: The samples were generally measured without any special treatment other than the application of slight pressure to get a flat surface. Silicon single crystal sample holders were used (0.1, 0.5 or 1 mm deep). The samples were rotated during the measurement.

[0130] Raman microscopy: Renishaw inVia Reflex Raman System. Stabilized diode laser with 785 nm excitation and an NIR enhanced Peltier-cooled CCD camera as the detector. Measurements were carried out with a long working distance 20 objective. Wavenumber range 2000-100 cm.sup.1, 10 s detection time, three accumulations per spectrum.

[0131] Solvents: For all experiments, Fluka, Merck or ABCR analytical grade solvents were used.

[0132] TG-FTIR: Thermogravimetric measurements were carried out with a Netzsch Thermo-Microbalance TG 209 coupled to a Bruker FTIR Spectrometer Vector 22 or IFS 28 (sample pans with a pinhole, N2 atmosphere, heating rate 10 C./min, range 25 C. to 350 C.).

Example 3

Inhibition Assay of DHODH Activity

[0133] The standard assay mixture contained 50 M decyclo ubichinone, 100 M dihydroorotate, 60 M 2,6-dichloroindophenol, as well as 20 mU DHODH. The volume activity of the recombinant enzyme used was 30 U/ml. Measurements were conducted in 50 mM TrisHCl (150 mM KCl, 0.1% Triton X-100, pH 8.0) at 30 C. in a final volume of 1 ml. The components were mixed, and the reaction was started by adding dihydroorotate. The course of reaction was followed by spectrophotometrically measuring the decrease in absorption at 600 nm for 2 min.

[0134] Inhibitory studies were conducted in a standard assay with additional variable amounts of inhibitor. For the determination of the IC.sub.50 values (concentration of inhibitor required for 50% inhibition) at least five different inhibitor concentrations were applied.

[0135] These investigations were carried out with recombinant human as well as with recombinant murine DHODH provided by Prof. M. Lffler, Marburg, Germany [M. Lffler, Chem. Biol. Interact. 124, (2000), 61-76].

[0136] As a reference the active metabolite of leflunomide A77-1726 (Compound 12) was used [J. Rickel et. al. Biochemical Pharmacology 56 (1998), 1053-1060].

[0137] The results of the inhibition assay are shown in the above Table 1 of said publication of Rickel et. al. It is evident from the comparison of the IC.sub.50-values that the compounds used for the preparation of the salts according to the present invention not only have a comparable or even better inhibitory activity on the human enzyme than the active metabolite of leflunomide but also a higher specifity for the human enzyme.

Example 4

Proliferation Assay of Human T-Cells

[0138] Human peripheral blood mononuclear cells (PBMC) were obtained from healthy volunteers and transferred to RPMI1640 cell culture medium containing 10% dialyzed fetal calf serum. 80.000 cells per well were pipetted into a 96-well plate and phytohemagglutinin (PHA) was added in phosphate buffered saline to a final concentration of 20 g/ml to stimulate T-cell proliferation. Vidofludimus was added in dimethyl sulfoxide (DMSO, final concentration: 0.1 Vol %) to final concentrations ranging from 20 nM to 50 M. After incubation for 48 hours, cell proliferation was quantified using the cell proliferation ELISA BrdU (Roche) according to the manufacturer's instructions. Half maximal inhibition (IC.sub.50) was calculated using a 4-parameter sigmoidal curve fit. T-cell proliferation was inhibited by Vidofludimus with an IC.sub.50 of 4.1 M.

Example 5

Preparation of the Calcium Salts

[0139] The synthesis of the calcium salts of compounds of formula (I) is described in detail in WO 2012/001148, which is incorporated herein by reference.

[0140] In addition, the powder X-ray diffraction shown in FIG. 5 show that crystalline material was obtained, however with a pattern different from that of the free acid (see FIG. 6). With light microscopy the crystals were visualized (FIG. 4), DSC (differential scanning calorimetry) demonstrated a melting point of about 155 C. (indicating a melting of a solvate and of a non-solvated form), TG-FTIR (thermogravimetric analyzer-coupled Fourier-Transform Infrared) indicates that probably a methanol solvate and a hydrate were formed and dynamic vapor sorption revealed desolvation followed by 0.3% water uptake at about 85% r.h. and 0.4% water uptake at 95% r.h. (not reversible).

Example 6

Synthesis of the Polymorph A

[0141] Polymorph A of vidofludimus is produced as follows: [0142] a) adding to a mixture of calcium hydroxide and free acid of a compound according to formula I or a solvate and/or a hydrate thereof an organic solvent and water [0143] b) stirring the suspension obtained in step a) until a solution is obtained, [0144] c) at least partially evaporating said organic solvent and water to obtain a suspension of the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof) [0145] d) adding acetone, fully mixable with water to said suspension of the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof obtained in step c) [0146] e) stirring the suspension obtained in step d), [0147] f) recovering the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof from the mixture obtained in step e), and [0148] g) washing the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof obtained in step f) with the solvent mentioned in step d). [0149] h) slurring the isolated calcium salt a compound according to formula I or a solvate and/or a hydrate thereof obtained in step g) in an alcoholic solvent at 15-80 C. [0150] i) adding water to the slurry obtained in step h) at 15-85 C. [0151] j) recovering the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof from the mixture obtained in step e), and [0152] k) washing the calcium salt of a compound according to formula I or a solvate and/or a hydrate thereof obtained in step j) with the aprotic organic solvent mentioned in step d).

Example 7

Determination of the Bioavailability

[0153] Oral bioavailabilities of the Calcium salt and the free acid of Vidofludimus were compared in male Wistar rats. The free acid or the Calcium salt was filled into gelatine capsules and the animals received a single administration at a dose level of approximately 10 mg free acid equivalents per kilogram body weight.

[0154] Four male Wistar rats (body weight range: 250-275 g) per group were treated with either Vidofludimus free acid or its Calcium salt. The capsules were administered into the oesophagus of the animals using an application device. Venous blood samples were taken from the animals under isoflurane anaesthesia at the following time points after administration: 30 min; 1 h; 2 h; 4 h; 6 h; 8 h; 24 h; 28 h; 32 h and 48 h. Coagulation was inhibited using Na-heparin and plasma was generated by centrifugation of the blood samples. Plasma samples were analyzed for Vidofludimus by LC-MS/MS and pharmacokinetic parameters were calculated according to the mixed log linear trapezoidal method.

[0155] To examine the potassium salt, six female Lewis rats (body weight ca. 200 g) were treated with either Vidofludimus free acid or its potassium salt at a dose level of 30 mg/kg (free acid equivalents). The compounds were formulated in 0.5% methylcellulose in phosphate buffered saline and the animals were treated by oral gavage. Venous blood samples were taken from the animals under isoflurane anaesthesia at the following time points after administration: 30 min; 1 h; 2 h; 4 h; 8 h; 26 h; 33 h; 48 h and 72 h. Coagulation was inhibited using Na-heparin and plasma was generated by centrifugation of the blood samples. Plasma samples were analyzed for Vidofludimus by LC-MS/MS and pharmacokinetic parameters (AUC) were calculated according to the linear trapezoidal rule method.

[0156] Oral bioavailabilities of the salts were evaluated by comparing the areas under the plasma-concentration-time-curves (AUCs) and the maximally attained plasma concentrations (Cmax values) of Vidofludimus after administration of the salt with those observed after administration of the free acid. These ratios are shown in Table 2.

TABLE-US-00003 TABLE 2 Comparison of PK parameters after oral application of Vidofludimus to rats Compound AUC.sub.inf/AUC.sub.inf, free acid C.sub.max/C.sub.max, free acid Vidofludimus free acid 1 1 Potassium salt 0.96 1.09 Calcium salt 1.72 1.67

Example 8

[0157] The previous GMP-batch of the drug substance vidofludimus calcium (IM90838; batch RL01L156A1), used in phase I studies, was manufactured from the intermediate vidofludimus (VIDO-05; SC12267) at the same facility as the current batch, i.e. Patheon DPx Fine Chemicals Regensburg GmbHResCom, Regensburg, Germany. The intermediate vidofludimus used had been manufactured by Cambrex Karlskoga AB, Karlskoga, Sweden.

[0158] As the drug substance vidofludimus calcium generally incorporated the solvent tetrahydrofuran (THF) at levels of approx. 6,000 to 10,000 ppm the last step of the manufacturing process was optimised in order to reduce the THF level:

[0159] Crude vidofludimus calcium was treated with ethanol, forming an intermediate ethanol solvate which upon treatment with water gives the required polymorph of vidofludimus calcium as dihydrate. In the final drug substance ethanol is retained at levels of approx. 2,000 to 6,000 ppm which is acceptable. The process is described in section 2.1.S.2.2.

[0160] Results from the preliminary laboratory process are summarised below. Laboratory scale batches of approx. 20 g vidofludimus (VIDO-5) were transferred to vidofludimus calcium by the process described in section 3.2.S.2.2. Analytical results are summarised in Table 1.

TABLE-US-00004 TABLE 1 Analytical results for laboratory batches of vidofludimus calcium (IM90838) Batch no. JC3794 JC3800 JC3803 Test Specification Analytical Results Appearance White solid White solid White solid White solid Identity 1H-NMR Conforms with Conforms Conforms Conforms FTIR reference Conforms Conforms Conforms Assay VIDO-06 98-102% Not determined 100% 100.5% (IM90838; (HPLC) Assay calcium 4.9-5.9% (w/w) 5.2% 5.1% 5.3% (Titration) Impurities (% w/w) SC12219 .sup.1) <0.004% n.d. n.d. n.d. SC44107 .sup.2) 0.15% n.d. n.d. n.d. Single unknown <0.05% (RRT 0.92) <0.05% (RRT 0.68) <0.05% (RRT 0.73) impurities .sup.3) 0.1% <0.05% (RRT 0.92) <0.05% (RRT 0.92) Total impurities 0.5% 0.040% 0.045% 0.07% Residual solvents (HS-GC) THF 720 ppm 210 ppm 42 ppm 89 ppm Acetone 5,000 ppm n.d. 117 ppm 14 ppm Ethanol 5,000 ppm 4,777 ppm 2,361 ppm 4,038 ppm Total heavy n. det. .sup.4) n. det. .sup.4) n. det. .sup.4) metals .sup.4) Water content (KF) <5% (w/w) 4.6% 5.1% 4.8% Melting point (DSC) Report 171.5 C. 168.3 C. 166.2 C. n.d.: not detected .sup.1) SC12219 (VIDO-03; RRT 0.77, .sup.2) SC44107: RRT 0.13, .sup.3) report >0.05%, .sup.4) Not determined (n. det.) as not relevant; total heavy metals were determined to be 20 ppm in vidofludimus and no additional metal impurities are expected in the laboratory batches.

[0161] It can be noted that the laboratory batches of vidofludimus calcium contain THF below the guideline limit of NMT 720 ppm; however the ethanol content is determined up to approx. 5,000 ppm. No change in assay or in the impurity level is observed.