NOVEL METHOD FOR PREPARING (-)-CIBENZOLINE SUCCINATE

Abstract

The present invention relates to a crystal form of (−)-Cibenzoline succinate. In addition, the present invention relates to a method for preparing (−)-Cibenzoline succinate having a chiral purity of 99.9% or higher. Additionally, the present invention provides a method for preparing (−)-Cibenzoline succinate and a crystal form thereof.

Claims

1. (−)-Cibenzoline.chiral acid salt of formula (IVA), ##STR00029## wherein the chiral acid is selected from the group consisting of L-(+)-Tartaric acid, D-(−)-Tartaric acid, (R)-(−)-Mandelic acid, (S)-(+)-Mandelic acid, Dibenzoyl-L-tartaric acid, (+)-2,3-Dibenzoyl-D-tartaric acid, (−)-O,O′-Dibenzoyl-L-tartaric acid monohydrate, (+)-O,O-Dibenzoyl-D-tartaric acid monohydrate, (−)-O,O′-Dibenzoyl-L-tartaric acid mono(dimethylamide), Di-p-toluoyl-D-tartaric acid monohydrate, Di-p-toluoyl-L-tartaric acid monohydrate, (−)-O,O′-Di-p-toluoyl-L-tartaric acid, (+)-O,O′-Di-p-toluoyl-D-tartaric acid, (+)-O,O′-Di-p-toluoyl-D-tartaric acid, D-Glutamic acid, L-Glutamic acid, L-(−)-Malic acid, D-(+)-Malic acid, (−)-Menthyloxyacetic acid, (+)-Menthyloxyacetic acid, (R)-(+)-α-Methoxy-α-trifluoromethylphenylacetic acid, (S)-(−)-α-Methoxy-α-trifluoromethylphenylacetic acid, (R)-(−)-5-Oxo-2-tetrahydrofurancarboxylic acid, (S)-(+)-5-Oxo-2-tetrahydrofurancarboxylic acid, (R)-(+)-N-(1-Phenylethyl)phthalamic acid, (S)-(−)-N-(1-Phenylethyl)phthalamic acid, (R)-(−) Phenylpropionic acid, (S)-(+)-2-Phenylpropionic acid, L-Pyroglutamic acid, D-Pyroglutamic acid, D-(−)-Quinic acid, L-(+)-Quinic acid, L-Aspartic acid, D-Aspartic acid, (R)-1,4-Benzodioxane-2-carboxylic acid, (S)-1,4-Benzodioxane-2-carboxylic acid, N,N-Bis[(S)-(−)-1-phenylethyl]phthalamic acid, N,N-Bis[(R)-(+)-1-phenylethyl]phthalamic acid, (1S)-(+) Bromocamphor-10-sulfonic acid hydrate, (1R)-(−)-3 -Bromocamphor-10-sulfonic acid hydrate, (1S)-(−)-Camphanic acid, (1R)-(+)-Camphanic acid, (1R,3 S)-(+)-Camphoric acid, (1S,3R)-(−)-Camphoric acid, (1R)-(−)- 10-Camphorsulfonic acid, and (1 S)-(+)-10-Camphorsulfonic acid.

2. A pharmaceutical composition comprising (−)-Cibenzoline.chiral acid salt (IVA) according to claim 1 and a pharmaceutically acceptable carrier, diluent or excipient.

3. A process for the preparation of enantiomerically pure (−)-Cibenzoline succinic acid salt of formula (IA), ##STR00030## which comprises the steps of: a) a step of preparing the racemic Cibenzoline free base of formula (III) by treating the racemic Cibenzoline succinic acid salt of formula (II) with a base; ##STR00031## b) a step of obtaining the racemic Cibenzoline.chiral acid salt of formula (IIIA) by treating the racemic Cibenzoline free base of formula (III) with a chiral acid in the presence of solvent; ##STR00032## c) a step of isolating (−)-Cibenzoline.chiral acid salt of formula (IVA); ##STR00033## d) a step of preparing the (−)-Cibenzoline free base of formula (VA) by neutralizing the (−)-Cibenzoline.chiral acid salt of formula (IVA) with a base; and ##STR00034## e) a step of preparing (−)-Cibenzoline succinic acid salt of formula (IA) by treating the (−)-Cibenzoline free base of formula (VA) with succinic acid in presence of solvent.

4. The process as claimed in claim 3, wherein the chiral acid is selected from the group consisting of L-(+)-Tartaric acid, D-(−)-Tartaric acid, (R)-(−)-Mandelic acid, (S)-(+)-Mandelic acid, Dibenzoyl-L-tartaric acid, (+)-2,3-Dibenzoyl-D-tartaric acid, (−)-O,O′-Dibenzoyl-L-tartaric acid monohydrate, (+)-O,O-Dibenzoyl-D-tartaric acid monohydrate, (−)-O.O′-Dibenzoyl-L-tartaric acid mono(dimethylamide), Di-p-toluoyl-D-tartaric acid monohydrate, Di-p-toluoyl-L-tartaric acid monohydrate, (−)-O,O′-Di-p-toluoyl-L-tartaric acid, (+)-O,O′-Di-p-toluoyl-D-tartaric acid, (+)-O,O′-Di-p-toluoyl-D-tartaric acid, D-Glutamic acid, L-Glutamic acid, L-(−)-Malic acid, D-(+)-Malic acid, (−)-Menthyloxyacetic acid, (+)-Menthyloxyacetic acid, (R)-(+)-α-Methoxy-α-trifluoromethylphenylacetic acid, (S)-(−)-α-Methoxy-α-trifluoromethylphenylacetic acid, (R)-(−)-5-Oxo-2-tetrahydrofurancarboxylic acid, (S)-(+)-5-Oxo-2-tetrahydrofurancarboxylic acid, (R)-(+)-N-(1-Phenylethyl)phthalamic acid, (S)-(−)-N-(1-Phenylethyl)phthalamic acid, (R)-(−)-2-Phenylpropionic acid, (S)-(+)-2-Phenylpropionic acid, L-Pyroglutamic acid, D-Pyroglutamic acid, D-(−)-Quinic acid, L-(+)-Quinic acid, L-Aspartic acid, D-Aspartic acid, (R)-1,4-Benzodioxane-2-carboxylic acid, (S)-1,4-Benzodioxane-2-carboxylic acid, N,N-Bis[(S)-(−)-1-phenylethyl]phthalamic acid, N,N-Bis[(R)-(+)-1-phenylethyl]phthalamic acid, (1S)-(+)-3-Bromocamphor-10-sulfonic acid hydrate, (1R)-(-)-3-Bromocamphor-10-sulfonic acid hydrate, (1S)-(−)-Camphanic acid, (1R)-(+)-Camphanic acid, (1R,3S)-(+)-Camphoric acid, (1S,3R)-(−)-Camphoric acid, (1R)-(−)-10-Camphorsulfonic acid, and (1S)-(+)-10-Camphorsulfonic acid.

5. The process as claimed in claim 3, wherein the base is selected from an inorganic base like alkali metal hydroxides, such as sodium hydroxide, lithium hydroxide or potassium hydroxide and the like, or alkali metal carbonates, such as cesium carbonate, sodium carbonate, potassium carbonate or lithium carbonate and the like, or alkali metal bicarbonates such as sodium bicarbonate or potassium bicarbonate and the like or mixtures thereof.

6. The process as claimed in claim 3, wherein the solvent is selected from alcohols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol and the like, or esters, such as ethylacetate, methylacetate, butyl acetate, isopropyl acetate, methoxy ethyl acetate and the like, or aliphatic hydrocarbons, such as heptane, hexane and the like, or ketones, such as acetone, methyl isobutyl ketone, 2-pentanone, ethylmethylketone, diethylketone and the like, or aromatic hydrocarbons, such as benzene, toluene, xylene, chlorobenzene and the like, or halogenated hydrocarbons, such as chloroform, dichloromethane and the like, or ethers, such as methyl tert-butyl ether, diethyl ether, tetrahydrofuran, dioxane and the like, or aprotic polar solvents such as dimethylformamide, dimethylsulfoxide, acetonitrile or water and or mixtures thereof.

7. A crystalline form of (−)-Cibenzoline succinic acid salt of formula ##STR00035##

8. The crystalline form of (−)-Cibenzoline succinic acid salt as claimed in claim 7, wherein the crystalline form has an X-ray powder diffraction (XRPD) pattern comprising diffraction peaks at 11.2°, 14.1°, 17.3 °, 22.1°, 23.0°, and)24.3° (2θ±0.2°).

9. The crystalline form of (−)-Cibenzoline succinic acid salt as claimed in claim 8, wherein the crystalline form has the XRPD pattern further comprising one or more diffraction peaks selected from the group consisting of 17.6°, 18.2°, 21.4°, and)26.4° (2θ±0.2°).

10. The crystalline form of (−)-Cibenzoline succinic acid salt as claimed in claim 7, wherein the crystalline form has an XRPD pattern comprising diffraction peaks at 8.99°, 11.15°, 13.36°, 14.09°, 14.30°, 17.29°, 17.59°, 18.15°, 19.81°, 21.37°, 22.06°, 22.93°, 24.25°, 25.41°, 26.36°, 27.59°, and 29.50° (2θ).

11. The crystalline form of (−)-Cibenzoline succinic acid salt as claimed in claim 7, wherein the crystalline form has a differential scanning calorimetry (DSC) endothermic peak at 187to 193° C. at heating rate of 10° C./min.

12. The crystalline form of (−)-Cibenzoline succinic acid salt as claimed in claim 11, wherein the crystalline form has a differential scanning calorimetry (DSC) endothermic peak at 190±1° C. at heating rate of 10° C./min.

13. A process for the preparation of a crystalline form of (−)-Cibenzoline succinic acid salt, which comprises the steps of: a′) a sep of preparing a mixture by reacting (−)-Cibenzoline free base of Formula (VA) with succinic acid in the presence of a straight or branched C1-C5 alcohol; and ##STR00036## b′) a step of obtaining solid (−)-Cibenzoline succinic acid salt of Formula (IA) by cooling the mixture. ##STR00037##

14. The process as claimed in claim 13, wherein the straight or branched C1-C5 alcohol is one or more selected from the group consisting of methanol, ethanol, straight or branched propanol, straight or branched butanol, or straight or branched pentanol.

15. The process as claimed in claim 13, wherein the reaction is carried out at a temperature of 20-60° C. in the step a′).

16. The process as claimed in claim 13, wherein the cooling is carried out at a temperature of 0-10° C. in the step b′).

17. A pharmaceutical composition comprising the crystalline form of (−)-Cibenzoline succinic acid salt as claimed in claim 8 as an active ingredient and a pharmaceutically acceptable carrier, diluent, or excipient.

18. The composition of claim 17, which is of the form of a capsule or a tablet for oral administration.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0155] FIG. 1 illustrates the X-ray powder diffraction pattern of a crystalline form of (−)-Cibenzoline succinic acid salt according to Example 4.

[0156] FIG. 2 illustrates the differential scanning calorimetry (DSC) of a crystalline form of (−)-Cibenzoline succinic acid salt according to Example 4.

[0157] FIG. 3 illustrates FT-IR of (−)-Cibenzoline succinic acid salt according to Example 4.

[0158] FIG. 4 illustrates high-performance liquid chromatography (HPLC) of (−)-Cibenzoline succinic acid salt according to Example 4.

BEST MODE FOR INVENTION

[0159] The process details of the invention are provided in the examples given below, which are provided by way of illustration only and therefore should not be construed to limit the scope of the invention.

EXPERIMENTAL PROCEDURE:

Instrumental Analysis and Measurement Condition

1. Chiral Purity (HPLC) Analysis

[0160] Chiral purity (e.e) of the prepared compound was measured by high-performance liquid chromatography (HPLC) with measurement conditions as below.

TABLE-US-00002 TABLE 2 HPLC condition Column Chiralpak IC, 250 × 4.6 mm, 5 μm, column temperature: 35° C. Mobile a mixture of n-Hexane, Isopropyl alcohol, Ethanol and phase Diethyl amine in the ratio of 80:10:10:0.1 (v/v/v/v) flow rate 0.8 mL/min. detection 220 nm. Instrument System make: Shimadzu. LC-2030C, i-services. details
2. .sup.1H NMR and .sup.13C NMR Analysis

[0161] The nuclear magnetic resonance spectrum of (−)-Cibenzoline succinic acid salt was obtained by using Bruker advance-III FT-NMR. .sup.1H NMR was measured at 400 MHz (in DMSO-D.sub.6) and .sup.13C NMR was measured at 400 MHz (in CD.sub.3OD).

3. IR Analysis

[0162] IR analysis of (−)-Cibenzoline succinic acid salt was performed on a PerkinElmer spectrum FT-IR spectrophotometer. IR spectrum was recorded by using a KBr disc.

4. Mass Spectral Analysis

[0163] Mass spectral analysis of (−)-Cibenzoline succinic acid salt was performed on an Agilent LCQ Fleet Thermo-ion trap mass spectrometer with Electro Spray Ionization (ESI).

5. UV-Visible Spectroscopy Analysis

[0164] UV-visible spectroscopy analysis of (−)-Cibenzoline succinic acid salt was performed by using a UV visible spectrophotometer of Perkin-Elmer (model Lambda 25). A solution of 10 μg/ml was prepared by dissolving (−)-Cibenzoline succinic acid salt in methanol as solvent and scanned from 200 nm to 400 nm.

6. Specific Optical Rotation Analysis

[0165] Specific optical rotation analysis of a (−)-Cibenzoline succinic acid salt solution whose concentration is 1.401g/100ml (in methanol) was performed on Agilent Autopol V, Serial #81225 at room temperature.

EXAMPLE

Example 1. Preparation of (±)-Cibenzoline Free Base

[0166] A suspension of (±)-Cibenzoline succinic acid salt (50 g) was stirred in water (200 ml) and basified with 10% sodium hydroxide solution to pH 10.5-10.8 over 30 minutes at 25-30° C. and extracted with ethyl acetate (400 ml). The obtained organic layer was dried over anhydrous sodium sulphate, followed by concentration under reduced pressure (400- 20 mmHg) at below 45° C. to afford a white solid as (±)-Cibenzoline free base (30 g).

[Chiral purity measured by chiral HPLC: mixture of (−)-Cibenzoline 48.76% and (+)-Cibenzoline 51.24%]

Example 2. Preparation of (−)-Cibenzoline-D-tartaric Acid Salt

[0167] (±)-Cibenzoline free base (15.0 g, Example 1) was dissolved in acetonitrile (250 ml), stirred at 25-30° C. for 15 min and then added D-(−)-tartaric acid (1.0 m. eq.) solution in water (30 ml) over a period of 20 min. at 25-30° C. The resultant mixture was stirred for 30 min, followed by addition of methyl tert butyl ether (MTBE, 250 ml) over a period of 20 min. and then stirred for 2.5 hours at room temperature. The reaction mixture was heated to 50-55° C. and stir for 1 hour and then allowed to cool at 25-30° C. and stir for 1 hour. The obtained solid was filtered and washed with acetonitrile (23 ml) to afford (−)-Cibenzoline-D-tartaric acid salt (6.4 g) with 99.0% chiral purity measured by chiral HPLC. (yield: 41(w/w) %)

[0168] .sup.1H-NMR (400 MHz, CD3OD): 7.38(m, 6H); 7.29(m, 3H); 7.20(m, 1H); 4.40(s, 2H); 3.71(m, 2H); 3.52(m, 2H); 2.83(t, 1H); 2.34(t, 1H); 1.90(t, 1H) ppm.

[0169] .sup.13C-NMR (100 MHz, CD3OD): 177.01, 170.68, 144.71, 139.88, 130.73, 129.82, 129.72, 128.90, 128.77, 128.19, 74.21, 45.52, 42.54, 23.02, 20.11.

[0170] IR (cm.sup.−1): 1731.23, 3531.63.

Example 3. Preparation of (−)-Cibenzoline Free Base

[0171] (−)-Cibenzoline-D-tartaric acid salt (5.0 g, example 2) was added in water (25 ml) and basified with saturated sodium bicarbonate solution (50 ml) at 25-30° C. and extracted with dichloromethane (200 ml). The extracted dichloromethane layer was dried over anhydrous sodium sulphate and followed by distillation under reduced pressure (500-20 mmHg) at below 40° C. to get the semisolid as a (−)-Cibenzoline free base (3.0 g) with [α].sub.D-153.82 and 99.09% chiral purity measured by chiral HPLC.

Example 4. Preparation of (−)-Cibenzoline Succinic Acid Salt

[0172] (−)-Cibezoline base (2.5 g, example 3) was dissolved in isopropanol (25 ml) and stirred at 50-55° C., followed by addition of succinic acid (1.0 m. eq.) solution in methanol (12.5 ml) over a period of 10 min and then stirred at 25-30° C. for 30 min, allowed to cooled at 0-5° C. for 1.5 hours. The resultant white solid was filtered, washed with isopropanol (3.75 ml) and then dried at 40-45° C. under vacuum to afford pure (-)-Cibezoline succinic acid salt (3.2 g) with 99.9% chiral purity measured by chiral HPLC (FIG. 4).

[0173] .sup.1H-NMR (400 MHz, CD3OD): 7.38(m, 6H); 7.29(m, 3H); 7.21(m, 1H); 3.71(m, 2H); 3.53(m, 2H); 2.82(m, 1H); 2.50(s, 4H); 2.36(t, 1H); 1.91(m, 1H) ppm.

[0174] .sup.13C-NMR (100 MHz, CD3OD): 179.20, 170.55, 141.73, 139.83, 130.70, 129.78, 129.69, 128.84, 128.76, 128.16, 45.41, 42.41, 32.96, 23.00, 21.01 ppm.

[0175] IR spectrum: 1674.96 cm.sup.−1 (Acid C═O stretching vibration), 2954.43 cm.sup.−1(Sp3 stretching vibration) (FIG. 3).

[0176] M.w: 380.44

[0177] m/z of (−)-Cibenzoline: 263.35(theoretical), 263(observed)

[0178] UV absorption: 1.155 absorption at 202.5 nm

[0179] Specific Optical Rotation: [α].sub.D-124.47; Rotation—VE.

Example 5. Preparation of (±) Cibenzoline-L-tartaric Acid Salt

[0180] (±)-Cibenzoline free base (15.0 g, Example 1) was dissolved in acetonitrile (255 ml), stirred at 25-30° C. for 15 min and then added L-(+) tartaric acid (1.0 m. eq.) solution in water (35 ml) over a period of 15 min at 25-30° C. and stir for 30 min, further added methyl tertiary butyl ether (260 ml) over a period of 20 min and stirred mixture for 2-hours at the same temperature. The obtained mixture was heated to 50-55° C. for 1.5 hours and allowed to cool at 25-30° C. and stir for 1 hour at same temperature. The resultant solid was filtered and washed with acetonitrile (30 ml) to afford of (+)- Cibenzoline-L-tartaric acid salt (6.0 g) with 99% purity by chiral HPLC and then filtrate was distilled out under reduced pressure to get the oil residue of (±)-Cibenzoline-L-tartaric acid salt.

[In which content mixture of ˜70% (−) Cibenzoline-L-tartaric acid salt and ˜30% (+) Cibenzoline-L-tartaric acid salt]

Example 6. Preparation of (±)-Cibenzoline Free Base

[0181] (±)-Cibenzoline-L-tartaric acid salt (45g, Example 5) was added in water (225 ml) and basified with saturated aqueous sodium bicarbonate solution (450 ml) over 30 minutes then extracted with dichloromethane (600 ml). The extracted dichloromethane layer was dried over anhydrous sodium sulphate and followed by distillation under reduced pressure (500-20 mmHg) at below 40° C. to get the semisolid of (±)-Cibenzoline free base (28.0 g).

Example 7. Preparation of (−)-Cibenzoline-D-tartaric Acid Salt

[0182] (±)-Cibenzoline free base (18g, example 6) was dissolved in acetonitrile (300 ml) and stirred at 25-30° C. for 15 min, followed by addition of one molar equivalent aqueous D-(−)-tartaric acid (36 ml) over a period of 15 min at 25-30° C. The resultant solution was stirred for 30 min and then added methyl tertiary butyl ether (300 ml) over a period of 20 min, stirred for 2.5 hours at room temperature. The obtained mixture was heated to 50-55° C., stir for 1 hour and then allowed to cool at 25-30° C. The resultant solid was filtered and washed with acetonitrile (27 ml) to afford of (−)-Cibenzoline-D-tartaric acid salt (11.2 g) with 90-99% chiral purity measured by chiral HPLC.

Example 8. Purification of (−)-Cibenzoline-D-tartaric Acid Salt

[0183] A suspension of crude (−)-Cibenzoline-D-tartaric acid salt (10.0 g, example 7) in mixture of acetonitrile (55 ml) and water (6.5 ml) at 50-55° C., followed by addition of methyl tert-butyl ether (55 ml) and stir for 30 minutes. The resultant suspension was allowed to cool at 25-30° C. The obtained solid was filtered, washed with mixture of (1:1) acetonitrile: methyl tert-butyl ether (12.2 ml), water (0.8 ml) and dried at 45-50° C. to afford the pure (−)-Cibenzoline-D-tartaric acid salt (9.3 g) with≥99% chiral purity measured by chiral HPLC.

Example 9. Preparation of (−)-Cibenzoline Free Base

[0184] (−)-Cibenzoline-D-tartaric acid salt (10 g, example 7 or 8) was added in water (50 ml) and basified with saturated sodium bicarbonate solution (100 ml) and extracted with dichloromethane (400 ml). The extracted layer was dried over anhydrous sodium sulphate and followed by distillation to get the semisolid as a (−)-Cibenzoline free base (6.2 g) with≥99% chiral purity measured by chiral HPLC.

Example 10. Preparation of (−)-Cibenzoline Succinic Acid Salt

[0185] A solution of (−)-Cibezoline free base (5.0 g, example 9) in isopropanol (50 ml), was stirred at 50° C., followed by addition of succinic acid (1.0 m. eq.) solution in methanol (28 ml) over a period of 10 min and then stirred at 25-30° C. for 30 min, allowed to cool at 0-5° C. for 1 hours. The resultant white solid was filtered and dried at 40-45° C. under vacuum to afford pure (−)-Cibenzoline succinic acid salt (6.3 g) with ≥99% chiral purity measured by chiral HPLC.

EXPERIMENTAL EXAMPLE

Experimental Example 1. X-Ray Powder Diffraction (XRPD) Analysis

[0186] The X-ray powder diffraction (XRPD) pattern of (−)-Cibenzoline succinic acid salt of Example 4 was measured under below conditions and the results are presented in FIG. 1.

TABLE-US-00003 TABLE 3 XRPD condition Start 2.000 End 49.998 Step Size 0.018 Time per Step (sec/step) 92.40 Temperature 25° C. (Room) Goniometer Radius 141.0 2-theta (°) 2.000 Theta (°) 1.000 Phi 0.00 Anode Cu ka1 1.54060 ka2 1.54439 ka2 Ratio 0.50000 kβ 1.54060 Generator kV 30.0 Generator mA 10.0 Detector Name LynxEye PSD Opening 5.015 Sample rotation speed 15.000 Divergence Slit n.a  Anliscatter Slit n.a. SUt Mode n.a. X-Offset 0.000 Displacement 0.000 Y-Scale Factor 1 Y-Offset 0 Humidity n.a. Curvature 1.000

[0187] As shown in FIG. 1, (−)-Cibenzoline succinic acid salt of Example 4 has an XRPD pattern with peaks at specific 20 values and is therefore the crystalline form.

Experimental Example 2. Differential Scanning Calorimetry (DSC) Analysis

[0188] Differential scanning calorimetry analysis was conducted on the crystalline form of Example 4 under below conditions and the results are shwon in FIG. 2. [0189] Manufacturer: Metter Toredo [0190] Model name: DSC 1 STARE system [0191] Heating rate: 25.0° C.˜250.0° C. (10.00K/min), 250.0 ° C. (10min), 250.0° C. ˜40° C. (−10.00K/min) [0192] Temperature range: 25° C.˜250° C./250° C.˜40° C. [0193] N2 speed: 100 ml/min.

[0194] As shown in FIG. 2, the crystalline form according to the embodiments of the present invention has an endothermic peak at 190.00° C.±2° C. in Differential scanning calorimetry.

Experimental Example 3. Long-Term Storage Stability Test

[0195] Long-term storage stability of the crystalline form of (−)-Cibenzoline succinic acid salt of Example 4 was tested under long-term storage conditions.

[0196] And related substances was measured by HPLC under below conditions.

TABLE-US-00004 TABLE 4 Related substances by HPLC (% w/w): Instrumentation: a) A High Performance Liquid Chromatography system with gradient elution capability, a Spectrophotometric UV detector and an auto sampler (Waters Alliance 2695 separations module, Waters 2487 dual λ absorbance detector or equivalent). b) Data handling system (Waters Empower work station or equivalent). Column Imtakt Unison UK-Phenyl, 250 × 4.6 mm, 3.0 μm Flow rate 1.0 mL/min UV Detector 230 nm Buffer 10 mL Potassium dihydrogen orthophosphate (KH.sub.2PO.sub.4) in to 1000 mL of water ph 4.5. Mobile phase-A Buffer Solution-A Transfer about 1 mL of Orthophosphoric acid (~85%) in to a 1000 mL of Acetonitrile and mix well. Mobile phase-B Prepare a degassed mixture of Solution-A and Water in the ratio of 70:30 (v/v) Diluent Prepare a degassed mixture of Acetonitrile and Water in the ratio of 50:50 (v/v)
<Packing details>- Primary packing: (−)-Cibenzoline succinic acid salt obtained by Example 4 shall be packed in transparent LDPE bag, twist and tie with Strip seal. [0197] Secondary packing: The above bag shall be kept in Black color LDPE bag, twist and tie with Strip seal. [0198] Tertiary packing: The above bag shall be kept Triple laminated aluminum bag with heat seal. Keep this bag in HDPE drum and close with lid.

[0199] Specifically, the crystalline form of Example 4 was packed in three levels and subjected to the test at a temperature of 25±2 ° C. and a relative humidity of 60±5%. The results are provided in Table 5.

TABLE-US-00005 TABLE 5 Parameter Specification Initial 1-month 2-month 3-month 6-month Description A White to off-white A White A White A White A White A White crystalline powder crystalline crystalline crystalline crystalline crystalline powder powder powder powder powder Identification by IR The infrared absorption Complies Complies Complies Complies Complies peaks observed at 1674 ± 5 cm.sup.−1 and 2954 ± 5 cm.sup.−1 Loss on drying at 105° C. Not more than 0.50 0.11 0.04 0.07   0.14   0.18 for 3 hours(% w/w) Assay by potentiometry Not less than 98.0 and 100.1   99.9  100.1   100.2 100.2 (% w/w, on dried basis) not more than 102.0 Chiral purity by HPLC Not less than 99.0 100.0   100.0   100.0   100.0 100.0 (% Area normalization) S-Isomer Content Chiral purity by HPLC Not more than 1.0 Not Not Not Not Not (% Area normalization) detected detected detected detected detected R-Isomer Content Related Carbonitrile Not more than 0.20 Not Not Not Not Not ubstance ntermediate detected detected detected detected detected  HPLC(% w/w) Cyclopropanec Not more than 0.10 Not Not Not Not Not rboxamate detected detected detected detected detected Single aximum Not more than 0.10 0.01 0.01 0.01 Not Not nknown mpurity detected detected Total impurity Not more than 0.50 0.01 0.01 0.01 Not Not detected detected indicates data missing or illegible when filed

[0200] As shown in Table 5, a white crystalline powder form was uniformly maintained for six months under long-term storage conditions.

[0201] With respect to the loss on drying at 105° C. for 3 hours, the loss rate (% w/w) at the initial stage was 0.11%, which is less than 0.5%. After 1-6 months under long-term storage conditions, the loss rate after drying at 105° C. for 3 hours was on a similar level as observed at the initial stage.

[0202] The (S)-form ((−)-Cibenzoline) of Example 4 was not changed to (R)-form ((+)-Cibenzoline) under long-term storage conditions and stably maintained, demonstrating a remarkably excellent stability.

[0203] In addition, as confirmed from the potentiometry analysis results, it was measured between equal to or more than 98% and 102% at the initial stage and even after storing for 1-6 months, demonstrating that the initial level was maintained.

[0204] Impurities were nearly not detected under long-term storage conditions, demonstrating that the crystalline form of (−)-Cibenzoline succinic acid salt according to Example 4 maintained high purity with no change even under long-term storage conditions and therefore had an excellent stability.

Experimental Example 4. Accelerated Stability Test

[0205] Accelerated stability of the crystalline form of (−)-Cibenzoline succinic acid salt of Example 4 was tested under accelerated test conditions.

TABLE-US-00006 TABLE 6 Related substances by HPLC (% w/w): Instrumentation: c) A High Performance Liquid Chromatography system with gradient elution capability, a Spectrophotometric UV detector and an auto sampler (Waters Alliance 2695 separations module, Waters 2487 dual λ absorbance detector or equivalent). d) Data handling system (Waters Empower work station or equivalent). Column Imtakt Unison UK-Phenyl, 250 × 4.6 mm, 3.0 μm Flow rate 1.0 mL/min UV Detector 230 nm Buffer 10 mL Potassium dihydrogen orthophosphate (KH.sub.2PO.sub.4) in to 1000 mL of water ph 4.5. Mobile phase-A Buffer Solution-A Transfer about 1 mL of Orthophosphoric acid (~85%) in to a 1000 mL of Acetonitrile and mix well. Mobile phase-B Prepare a degassed mixture of Solution-A and Water in the ratio of 70:30 (v/v) Diluent Prepare a degassed mixture of Acetonitrile and Water in the ratio of 50:50 (v/v)
<Packing details>- Primary packing: (−)-Cibenzoline succinic acid salt obtained by Example 4 shall be packed in transparent LDPE bag, twist and tie with Strip seal. [0206] Secondary packing: The above bag shall be kept in Black color LDPE bag, twist and tie with Strip seal. [0207] Tertiary packing: The above bag shall be kept Triple laminated aluminum bag with heat seal. Keep this bag in HDPE drum and close with lid.

[0208] Specifically, the crystalline form of Example 4 was packed in three levels and subjected to the test at a temperature of 40±2 ° C. and a relative humidity of 75±5%. The results are provided in Table 7.

TABLE-US-00007 TABLE 7 Parameter Specification Initial 1-month 2-month 3-month 6-month Description A White to off-white A White A White A White A White A White crystalline powder crystalline crystalline crystalline crystalline crystalline powder powder powder powder powder Identification by IR The infrared absorption Complies Complies Complies Complies Complies peaks observed at 1674 ± 5 cm.sup.−1 and 2954 ± 5 cm.sup.−1 Loss on drying at 105° C. Not more than 0.50   0.11   0.15   0.12   0.09  0.10 for 3 hours(% w/w) Assay by potentiometry Not less than 98.0 and 100.1 100.1 100.3 100.1 99.6 (% w/w, on dried basis) not more than 102.0 Chiral purity by HPLC Not less than 99.0 100.0 100.0 100.0 100.0 100.0  (% Area normalization) S-Isomer Content Chiral purity by HPLC Not more than 1.0 Not Not Not Not Not (% Area normalization) detected detected detected detected detected R-Isomer Content Related Carbonitrile Not more than 0.20 Not Not Not Not Not Substance termediate detected detected detected detected detected by HPLC(% w/w) Cyclopropanecarb Not more than 0.10 Not Not Not Not Not xamate detected detected detected detected detected Single maximum Not more than 0.10 Not Not Not nknown impurity detected detected detected Total impurity Not more than 0.50   0.01   0.01 Not Not Not detected detected detected indicates data missing or illegible when filed

[0209] As shown in Table 7, a white crystalline powder form was uniformly maintained for six months under accelerated conditions. With respect to the loss on drying at 105° C. for 3 hours, the loss rate at the initial stage was 0.11% which is less than 0.5%. After 1-6 months under accelerated conditions, the loss rate after drying at 105° C. for 3 hours was on a similar level as observed at the initial stage.

[0210] The (S)-form ((−)-Cibenzoline) of Example 4 was not changed to (R)-form ((+)-Cibenzoline) under long-term storage conditions and stably maintained, demonstrating a remarkably excellent stability.

[0211] As confirmed from the potentiometry analysis results, it was measured between equal to or more than 98% and 102% at the initial stage and even after storing for 1-6 months, demonstrating that the initial level was maintained.

[0212] Impurities were nearly not detected under accelerated conditions, demonstrating that the crystalline form of (−)-Cibenzoline succinic acid salt according to according to Example 4 maintained high purity with no change even under accelerated conditions and therefore had an excellent stability.

Experimental Example 5. Particle Size Analysis

[0213] Particle size analysis of the crystalline form of (−)-Cibenzoline succinic acid salt of Example 4 was tested by using a particle size analyzer of Malvern (model MASSTERSIZER 3000). The powder sample was dispersed with a dispersion pressure of 2 bar. The results are provided in Table 8.

TABLE-US-00008 TABLE 8 d.sub.90 (μm) d.sub.50 (μm) d.sub.10 (μm) Classification 265 104 15.2 Very fine

[0214] The accompanying Table 9 (ref 2019 USP 42 NF 37 Volume 4 physical tests <811>powder fineness) indicates particle size distribution associated with corresponding values.

TABLE-US-00009 TABLE 9 Cumulative Distribution by Descriptive term X.sub.50 (μm) volume basis, Q3(x) Coarse  >355 Q3(355) < 0.50 Moderately Fine 180-355 Q3(180) < 0.50 and Q3(355) > 0.50 Fine 125-180 Q3(125) < 0.50 and Q3(180) > 0.50 Very Fine ≤125 Q3(125) < 0.50

[0215] As confirmed from the Particle Size Analysis results, d.sub.50 (μm) was measured 104 (μm), demonstrating that the Particle Size was very fine.

Experimental Example 6. Hygroscopicity

[0216] The hygroscopicity was to describe the water vapor uptake behavior of solid by mass changes.

[0217] The hygroscopicity of the crystalline form of (−)-Cibenzoline succinic acid salt of Example 4 was tested under the conditions of 25±1° C. for 24 hours at 80±2% RH.

[0218] The result is presented in Table 10.

TABLE-US-00010 TABLE 10 Container weight with sample Container weight Container weight stored in chamber Mass (g) with sample (g) for 24 hours (g) change (%) 19.1582 24.1611 24.1621 0.01

[0219] The results of the hygroscopicity study shall be interpreted based on the criteria in Table 11 (ref. EUROPEAN PHARMACOPOEIA 9.0 volume 1 5.11. characters section in monographs).

TABLE-US-00011 TABLE 11 Descriptive term % Incorporation of water Deliquescent Sufficient water is absorbed to form a liquid Very hygroscopic Increase in mass is ≥15% Hygroscopic Increase in mass is <15% and ≥2% Slightly hygroscopic Increase in mass is <2% and ≥0.2%

[0220] As confirmed from the Hygroscopicity results, mass change was measured 0.01%, evaluating “Non hygroscopic”.

Experimental Example 7. Solubility

[0221] The solubility of the crystalline form of (−)-Cibenzoline succinic acid salt of Example 4 on three different pH media was tasted by using a HPLC of Agilent (model AGILENT 1260SERIES). The crystalline form of Example 4 was added until precipitated in each medium. Thereafter, the mixture was stirred for 1 hour and allowed to stand for one hour. 1 ml of the supernatant of the stationary solution was sampled and diluted 10 times with methanol. The diluted solvent was analyzed by HPLC, and the solubility was measured using the width of the (−)-Cibenzoline succinic acid salt peak. The HPLC analysis conditions are shown in Table 12. The results are summarized in Table 13.

TABLE-US-00012 TABLE 12 HPLC condition Column Inertsil ODS-3V, 4.6 × 150 mm, 5 um Mobile Buffer*: Acetonitrile = 650:350 phase *Buffer: Weigh and transfer about 2.16 g of Sodium 1- octanesulfonate and about 1.36 g of potassium phosphate monobasic into 1000 mL Milli-Q Water. Adjust the pH 5.7 ± 0.02 with diluted potassium hydroxide solution. flow rate 1.5 mL/min detection UV, 222 nm

TABLE-US-00013 TABLE 13 Media/Buffer Avg. (mg/mL) at 37° C. Purified water* 41.400 0.1N HCl (pH 1.0~1.2) 65.158 phosphate buffer (pH 6.8) 44.934 *Purified water was made by Water Purification System for Ultrapure Water of Millipore (Model: Milli-Q Integral).

[0222] The accompanying Table 14 (ref 2015 USP 38 NF 33 general notices and requirements 5.30. Description and Solubility) indicates solubility associated with corresponding values.

TABLE-US-00014 TABLE 14 Part of the solvent(ml) required Descriptive term per part of solute (1 g) Very soluble Less than 1 Freely soluble From 1 to 10 Soluble From 1 to 30 Sparingly soluble From 30 to 100 Slightly soluble From 100 to 1,000 Very slightly From 1,000 to 10,000 soluble Practically 10,000 and over insoluble

[0223] As confirmed from the solubility results, average solubility was measured more than 40 mg/mL (equal to 1g/25mL) evaluating high solubility.