A new stable crystalline form of roxadustat and preparation method thereof

Abstract

The present invention provides a new crystalline form of Roxadustat which is chemically known as 2-[(4-Hydroxy-l-methyl-7-phenoxy- iso quinoline-3-carbonyl)-amino]-acetic acid and preparation of its stable crystalline polymorph "Form X".

Description

[0001] A NEW STABLE CRYSTALLINE FORM OF ROXADUSTAT AND PREPARATION METHOD THEREOF

[0002] Technical Field

[0003] The present invention provides a new crystalline form of Roxadustat which is chemically known as 2-[(4-Hydroxy-l-methyl-7-phenoxy-isoquinoline-3-carbonyl)-amino]-acetic acid and preparation of its stable crystalline polymorph “Form X”.

[0004] Background Art

[0005] Roxadustat (compound I) is used for treatment of adult patients with symptomatic anemia associated with chronic kidney disease (CKD) is chemia, and hypoxia as an oral small molecule inhibitor of HIF prolyl hydroxylases or HIF-PHs, which is marketed under the brand name Evrenzo in the EU and JP. Roxadustat is chemically designated as 2-[(4-Hydroxy-l-methyl-7- phenoxy- iso quinoline-3-carbonyl)-amino]-acetic acid and structurally represented as below;

[0006] Compound I

[0007] Arend et al. in US US7323475B2 provided the first disclosure of a process for isolation of compound I, Example D-81 by referring Example D-78, which does not mention any details about the character of the solid form of the product.

[0008] Witschi et al. in WO2014014835 disclose various salts, amorphous form and crystalline forms of compound I and their processes for the preparation. This application contains Roxadustat Form A, Form B (hemihydrate), Form C (hexafluropropan-2-ol solvate), Form D (DMSO:Water co-solvate), Sodium salt, Potassium salt, L-arginine salt, L-lysine salt, Ethanolamine salt, Diethanolamine salt, Tromethamine salt, Hydrochloric acid salt, Sulfuric acid salt, Methanesulfonic acid salt, Amorphous form, bis-TEA (triethylamine) salt, hemi Calcium and Magnesium salts. It is stated that among the declared polymorphs, Form B, C, D and the amorphous crystal structures are not stable and transform to Form A as time goes by.

[0009] Li et al. in W02020135058A1 disclose 12 crystalline forms ARZ-A to ARZ-L of compound I. The crystal form ARZ-L is the hydrochloride crystal form of compound I. The TGA results of other forms has high weight loss (above 6%), and the solvent residual results is relatively high, which is unsuitable for an API manufacturing process.

[0010] Kallem et al. in W02019030711 disclose crystalline forms such as form 6 (hydrate), form y (Formic acid: Water co-solvate) and co-crystals of compound I in addition to its L-proline, nicotinamide and urea co-crystals. Among them, crystalline form y suffers from ICH solvent residue limits. The crystal form 6 (hydrate) is unstable, and by heating it transforms into crystal form A disclosed in WO2014014835.

[0011] Jinchao et al. in CN111320583A disclose a DL-proline co-crystal of compound I and four crystal forms (E, F, G, H).

[0012] Chen et al. in WO2021077994A1 disclose an anhydrous crystalline form (form CSI) of compound I. Due to extended crystallization periods or rapid evaporation processes, the preparation method as declared is inconvenient and challenging for API manufacturing of the form CSI exhibits inferior characteristics.

[0013] The discovery of a new salt of an active ingredient or a new polymorph thereof provides an opportunity to improve its characteristics, increasing the possibilities available to a formulation specialist when developing a new pharmaceutical form, a drug with a particular release profile or a specific dissolution degree.

[0014] Based on these considerations, there still appears a need for new polymorph of Roxadustat thereof having further improved physical and / or chemical properties. Hence, it was thought worthwhile by the inventors of the present application to explore pharmaceutically novel polymorph of Roxadustat with good chemical purity and improved stability characteristics, which may further improve the characteristics of Roxadustat in finished medicinal product.

[0015] Summary of the invention

[0016] The object of the present invention is to provide a new polymorphic form of Roxadustat and process for the preparation of this novel polymorphic form of Roxadustat.

[0017] Technical Problem

[0018] Active pharmaceutical ingredients are individual components that are used as a part of a finished pharmaceutical drug or medicinal product, where they provide the pharmacological activity.

[0019] Research and development projects in the pharmaceutical industry mainly aim to investigate different possible salts, polymorphs and processes to produce these APIs. Polymorphism, the occurrence of different crystal forms, is a property of some molecules and molecular complexes. A single molecule, may give rise to a variety of crystalline forms having distinct crystal structures and physical properties. Difference in the physical properties of different crystalline forms results from the orientation and intermolecular interactions of adjacent molecules or complexes in the bulk solid.

[0020] The pharmaceutical industry widely recognizes the correlation between the polymorphic forms of a pharmaceutically active substance and the resulting pharmaceutical product. The specific polymorphic form significantly influences the formulation of pharmaceutical products.

[0021] The solid state form of an active pharmaceutical ingredient may affect its stability as in finished product.

[0022] Stability of active pharmaceutical ingredients (APIs) is the key factor in stability evaluation of finished pharmaceutical products (FPPs). On this ground, stability testing of API in FPP must be conducted.

[0023] From a storage perspective, the relative humidity and / or temperature of the environment may cause increase in impurity amount of API. Hence, stable polymorph which does not change on storage and does not require any special conditions for storage, is always preferred.

[0024] The exploration and identification of new polymorphic forms for an active pharmaceutical ingredient present a promising avenue to enhance the performance attributes of the final pharmaceutical product.

[0025] According to the need, studies have been done to develop novel polymorph of Roxadustat having advantageous properties which are useful and suitable for the preparation of various pharmaceutical compositions.

[0026] Solution to Problem

[0027] The primary objective of this invention is to offer an enhanced and straightforward process for producing a novel anhydrous polymorphic form for Roxadustat, which meets pharmaceutical requirements such as storage, shelf life and high purity.

[0028] Description of embodiments

[0029] The aspect of the present invention relates to a novel polymorphic anhydrous form of compound I, herein after designated as Form X. Form X is characterized by an XRPD pattern having characteristic peaks at 3.5 ± 0.2, 6.82 ± 0.2, 11.19 ± 0.2, 12.22 ± 0.2, 13.02 ± 0.2, 16.23 ± 0.2, 16.91 ± 0.2, 18.82 ± 0.2, 24.73 ± 0.2 and 26.89 ± 0.2 degree 2-theta. The aspect of this current invention pertains to a method for preparing crystalline Form X of compound I, involving; a) providing a mixture of compound I by addition of water and polar aprotic solvent. b) then stirring the mixture at a suitable temperature for a suitable time and filtered the to obtain clear solution, c) adding sodium hydroxide (NaOH) or potassium carbonate (K2CO3) to the solution at a suitable temperature for a suitable time, d) adjusting pH to the appropriate range with HC1 (aq) and stirring the mixture at a suitable temperature for a suitable time, e) filtering the crystals, washing with a suitable solvent and f) drying the crystals under a vacuum at the specified temperature.

[0030] Wherein suitable solvent in step (a) and (e) is selected from, 2-propanol, 1 -propanol, 1 -butanol, 2-butanol, tert-butyl alcohol, 1 -pentanol, 2-pentanol, amyl alcohol, ethylene glycol, glycerol, acetone, butanone, 2-pentanone, 3-pentanone, methyl butyl ketone, methyl isobutyl ketone, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, tert-butyl acetate, isobutyl acetate, toluene, xylene, chloroform, dichloromethane, carbontetrachloride, ethylene dichloride, chlorobenzene, acetonitrile, diethyl ether, diisopropyl ether, tert-butyl methyl ether, dibutyl ether, tetrahydrofuran (THF), 1,4-dioxane, 2-methoxyethanol, AW-di methyl formamide (DMF), 7V,7V-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), pyridine, dimethylsulfoxide (DMSO), sulfolane, formamide, acetamide, propanamide, pyridine, or mixtures thereof.

[0031] The suitable temperature used in step (b), (c) and (d) is selected from room temperature to reflux temperature of the solvent used.

[0032] The suitable time used to stir the mixture in step (b), (c) and (d) is between 1 - 16 hours.

[0033] The appropriate NaOH or K2CO3 amount used in step (c) is between 1.00 - 2.00 equivalent.

[0034] The suitable range to adjust pH in step (d) is 5.5 - 6.5.

[0035] The suitable temperature to adjust pH used in step (d) is from 5°C to 35°C.

[0036] The suitable temperature to dry the product in step (f) is from 50°C to 90°C.

[0037] The improved method is simple, repeatable, cost-effective and suitable for industrial scale manufacturing.

[0038] The purity of the active ingredient significantly influences its efficacy and other crucial properties essential in pharmaceutical processing. For instance, diminished pourability or flowability of the crystalline form can impair its ability to be compressed into tablets, potentially affecting its overall effectiveness.

[0039] The process of the present invention affords crystalline Form X of compound I in high purity and high yield. The crystalline Form X is obtained having purity greater than 99% by area percentage in HPLC.

[0040] Stability is a critical factor in drug development. It refers to the ability of a pharmaceutical product within a designated container or closure system to maintain its chemical, physical, microbiological, therapeutic, and toxicological properties within specified limits. This endurance ensures the product's quality attributes such as identity, purity, and strength are retained until the drug's expiration.

[0041] The stability of a pharmaceutical product is significantly affected by alterations in the solid- state form of the API (active pharmaceutical ingredient). Changes in the API's solid-state form can arise from conditions during the product manufacturing process. Processes like grinding, milling, heating, and compression are examples that may induce polymorphic alterations. Manufacturing methods involving solvents (such as wet granulation, solutions, or suspensions) can also contribute to changes in the API's solid-state form.

[0042] These variations encompass polymorphic shifts, the creation of hydrates / solvates, and reactions involving dehydration / desolvation in the API's solid-state structure. Such modifications may result in stability issues within the finished pharmaceutical products (FPPs).

[0043] Absolutely, the crystalline stability of the API plays a pivotal role in meeting the requirements for a qualified pharmaceutical product. Utilizing stable polymorphs of the API in pharmaceutical formulations is essential to ensure the stability and quality of the final product.

[0044] For this aspect, crystalline stability of crystalline Form X was investigated under the condition 25 °C, 60% relative humidity (RH) for 6 months after preparation.

[0045] The crystalline stability referred to here, is the stability of a polymorphic form of API with respect to polymorph transformations, hydration or dehydration, salt disproportionation, crystallization, or amorphization through time under the condition 25 °C, 60% RH for 6 months after preparation.

[0046] The crystalline stability of Roxadustat Form X is investigated and determined by X-ray powder diffraction method. Results show that any polymorphic transformation to another crystal form or any degradation in crystalline Form X did not occur. Crystalline Form X shows crystalline stability under 25 °C, 60% RH for 6 months. X-ray diffractogram of crystalline Form X kept under the conditions at 25 °C, 60% RH for 6 months is given in Fig. 7 clearly shows that 2- theta values of characteristic peaks did not change when exposed to accelerated stability conditions.

[0047] The chemical stability of crystalline Form X is also important and its stability in finished product at room-temperature storage can be predicted from shorter-term storage under accelerated conditions of high temperature and humidity.

[0048] In the present invention, samples of obtained crystalline Form X are stored for 6 months in stability chambers under following condition of 25 °C 60% to test chemical stability. The chemical stability of the samples was determined by HPLC method and appearance solution test according to reference solution.

[0049] Table 1 shows the stability results of Form X prepared according to the present invention in comparison to Form A prepared according to W02004108681A1. Form X and Form A were kept at 25°C and 60% relative humidity conditions for 6 months. At 25 °C and 60 % RH condition, initial total impurity amounts were 0.10% for Form X and 0.24% for Form A. The total impurity amounts at the end of 6 months were 0.14% for Form X and 0.29% for Form A. The total impurity levels indicated that Form X and Form A share similar stability characteristics.

[0050] Table 1. Roxadustat stability test results of Form X versus Form A

[0051] *Packed samples were kept at 25 °C and 60% relative humidity

[0052] **Prepared according to W02004108681A1 patent

[0053] In addition to examining relative humidity conditions, forced degradation studies were conducted to assess the crystalline stability of Form X. Forced degradation tests are studies used to assess the stability of active pharmaceutical ingredients (APIs) and their formulations. These tests are performed submitting the API under extreme conditions in order to know the main degradation products in a short period of time. Table 2 shows the stability results of Form X prepared according to the present invention in comparison to Form A prepared according to W02004108681A1. Form X and Form A were kept at 105°C for 15 days, day light and UV light for 25 days. The initial total impurity amounts were 0.10% for Form X and 0.24% for Form A. The total impurity amounts for the thermal degradation results were 0.19% for Form X and 0.46% for Form A. The total impurity amounts for the day light results were 0.14% for Form X and 0.30% for Form A. The total impurity amounts for the UV light results were 0.12% for Form X and 0.34% for Form A. The total impurity amounts showed that Form X is slightly more stable than Form A.

[0054] Table 2. Roxadustat forced degradation results of Form X versus Form A

[0055] *Prepared according to W02004108681A1 patent Ensuring the stability of APIs and their preparations under accelerated and rigorous conditions holds the utmost significance in pharmaceuticals. Throughout storage, transportation, and production, these substances may be exposed to varying temperatures and humidity levels due to seasonal and regional climate disparities and weather fluctuations. Crystalline Form X bulk drugs and preparations demonstrate commendable stability even under harsh environmental conditions. This resilience proves advantageous in mitigating the effects of deviations from ideal storage conditions on the drug's quality as specified on its label.

[0056] Brief description of the drawings:

[0057] Figure 1 shows the X-Ray Powder Diffraction (XRPD) pattern of compound I Form A

[0058] Figure 2 shows the X-Ray Powder Diffraction (XRPD) pattern of compound I Form X

[0059] Figure 3 shows the differential scanning calorimetry (DSC) thermogram of compound I Form X

[0060] Figure 4 shows the Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectra of compound I Form X

[0061] Figure 5 shows the1H-NMR spectrum of compound I Form X

[0062] Figure 6 shows the13C-NMR spectrum of compound I Form X

[0063] Figure 7 shows the X-Ray Powder Diffraction (XRPD) pattern of compound I Form X (25 °C, 60% RH for 6 months)

[0064] Instrumental parameters:

[0065] NMR:

[0066] !H and13C NMR spectra were recorded on a JOEL 400 MHz NMR spectrometer. Chemical shifts 6 are reported in parts per million (ppm) relative to the residual protons in the NMR solvent (DMSO- / 6: 62.5 and carbon resonance of the solvent (DMSO-t / 6: 640.00). NMR peak multiplicities were given as follows: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, br = broad, C, CH, CH2, CH3.

[0067] FTIR:

[0068] Samples were measured as neat by ATR (Attenuated Total Reflectance) on Shimadzu FTIR Spectrometer IR Prestige-21 (Shimadzu Corporation, Kyoto, Japan) in the range of 600 - 4000 cm-1with 20 scans and 4 cm-1resolution.

[0069] DSC:

[0070] Samples were measured on a Shimadzu DSC-60 Differential Scanning Calorimetry. The measurement conditions were as following:

[0071] Initial temperature: 30 °C Final temperature: 350 °C

[0072] Heating rate: 5 °C / min

[0073] Cell Aluminum

[0074] Atmosphere Nitrogen.

[0075] PXRD Method of Analysis:

[0076] XRPD samples were analyzed on a Shimadzu 6100 X-Ray Diffractometer. The measurement conditions were as following:

[0077] Radiation: CuKal (1.5406 A)

[0078] Kai ratio: 50%

[0079] Voltage: 40.0 kV

[0080] Current: 30.0 mA

[0081] Auto slit: not used

[0082] Divergence slit: 1.0°

[0083] Scatter slit: 1.0°

[0084] Receiving slit: 0.30 mm with a Graphite monochromator

[0085] Drive axis: Theta-2Theta

[0086] Scan range: 2.00 - 40.00°

[0087] Scan mode: Continuous scan

[0088] Scan speed: 2.0° / min

[0089] Sampling pitch: 0.02°

[0090] Preset time: 0.60 s

[0091] The following examples are provided to enable one skilled in the art to practice the invention and are merely illustrative of the invention. The examples should not be read as limiting the scope of the invention. EXAMPLES

[0092] EXAMPLE- 1: Preparation of Roxadustat Form X

[0093] Compound II Roxadustat

[0094] Compound I

[0095] Compound I was synthesized following the procedure in Org. Process Res. Dev. 2022, 26, 915-924 with some modification. In a reactor, ethyl 4-hydroxy-l-methyl-7- phenoxyisoquinoline-3-carboxylate (compound II, 50.12 g, 0.155 mol, 1.00 eq) and glycine (compound III, 14 g, 0.186 mol, 1.20 eq) were combined with N, A-di methyl formamide (250 mL). 1, 8-Diazabicyclo(5.4.0)undec-7-ene (DBU, 34.7 mL, 0.233 mol, 1.50 eq) was added to the mixture at room temperature. The resulting mixture was heated to 80 °C and stirred for 3 hours. Once the reaction was completed, the temperature was allowed to return to ambient levels, and 500 mL of water was introduced into the mixture which was extracted with toluene (1x500 mL and 2x250 mL). NaOH (6.8 g, 0.17 mol, 1.10 eq) was added to the clarified mixture and stirred for 1 hour at room temperature. Next, the aqueous phase was filtered through 0.45- micron filter paper. The pH was adjusted to a range between 6 and 6.1 by drop-wise adding IN HC1, followed by an additional hour of stirring at room temperature. Upon precipitation, the pH was readjusted to the 6-6.1 range using IN HC1. The precipitate was filtered and washed with water (2 x 50 mL) and EtOH (3 x 50 mL). The resulting off-white solid underwent vacuum drying at 80°C for 10 hours, Roxadustat Form X (50.5 g, 92.5%). HPLC purity: 99.34%, KF(%): 0.80.1H NMR (400 MHz, DMSO-t / 6) 8 (ppm) = 8.89 (t, J = 5.3 Hz, 1H), 8.28 (dd, J = 9.0, 0.5 Hz, 1H), 7.60 (dd, J = 2.4, 0.5 Hz, 1H), 7.54 - 7.44 (m, 3H), 7.28 - 7.22 (m, 1H), 7.20 - 7.15 (m, 2H), 3.86 (d, J = 5.4 Hz, 2H), 2.69 (s, 3H).13C NMR (100 MHz, DMSO-t / 6) 8 (ppm) = 171.07 (C), 169.66 (C), 158.21 (C), 156.17 (C), 153.34 (C), 147.16 (C), 131.86 (C), 130.90 (CH), 125.75 (CH), 125.03 (CH), 124.22 (C), 122.93 (CH), 120.27 (C), 119.99 (CH), 112.70 (CH), 42.60 (CH2), 22.03 (CH3). EXAMPLE-2: Preparation of Roxadustat Form A

[0096] Compound I

[0097] Compound IV

[0098] 2- [(4-benzyloxy- 1 -methyl-7 -phenoxy-isoquinoline-3-carbonyl)-amino] -acetic acid benzyl ester (compound IV) was synthesized following the methodology outlined in the W02004108681 patent. The hydrogenolysis of benzyl esters was subsequently carried out using the procedure detailed in the same patent. An oven-dried 500 mL threeneck round-bottom flask, capped with a glass stopper and a magnetic stirring bar, was evacuated under heating with a blow-drier for 15 min. After the flask was cooled down to ambient temperature, dry nitrogen was back-filled and the glass stopper was replaced with a rubber septum under a positive pressure of nitrogen. The flask was charged with Compund IV (1.6 g, 33.0 mmol, 1.00 eq), ethyl acetate (EtOAc, 120 ml), and methanol (MeOH, 600 ml) and then Palladium on activated charcaol (1.05 g, 10 wt% Pd) was added under positive pressure of N2. The solution underwent three cycles of evacuation and filling with hydrogen gas from a balloon. Subsequently, the resulting solution was vigorously stirred for 16 hours under a hydrogen atmosphere. Afterward, the mixture was filtered through a pad of celite. The celite and filter cake were thoroughly rinsed with EtOAc (4 x 150 mL), and the combined organic phases were concentrated under reduced pressure to yield the desired compound as a tan solid (1.02 g, 97%).

[0099] EXAMPLE-3: Preparation of Roxadustat Form X by using Roxadustat Form A

[0100] Roxadustat Form A was prepared by following Example 1 with some modifications, ethyl 4- hydroxy-l-methyl-7-phenoxyisoquinoline-3 -carboxylate (compound II, 10.02 g, 0.031 mol, 1.00 eq) and glycine (compound III, 2,8 g, 0.037 mol, 1.20 eq), 1,8-Diazabicyclo(5.4.0)undec- 7-ene (DBU, 6.94 mL, 0.047 mol, 1.50 eq) and V-di methyl formamide (50 mL). Once the reaction was completed, the temperature was allowed to return to ambient levels, and 100 mL of water was introduced into the mixture which was extracted with toluene (1x100 mL and 2x50 mL). The pH was adjusted to a range between 3 and 3.5 by drop- wise adding 6N HC1 and followed by an additional hour of stirring at room temperature. Upon precipitation, the precipitate was filtered and washed with water (2 x 10 mL) and EtOH (3 x 10 mL). The resulting pale yellow solid, Roxadustat Form A (10.5 g, 96%).

[0101] 5 g Roxadustat Form A was suspended with THF (10 mL) and water (50 mL) at room temperature. NaOH (0.68 g, 0.017 mol, 1.20 eq) was added to the mixture at room temperature and stirred for Ih. The mixture was filtered through 0.45-micron filter paper and pH was adjusted to a range between 6 and 6.1 by drop-wise adding IN HC1, followed by an additional hour of stirring at room temperature. Upon precipitation, the pH was readjusted to the 6-6.1 range using IN HC1. The precipitate was filtered and washed with water (2 x 10 mL) and EtOH (3 x 10 mL). The resulting off-white solid underwent vacuum drying at 80°C for 6 hours, Roxadustat Form X (4.65 g, 93%).

Claims

CLAIMS1. A crystalline form of Roxadustat designated Form X, characterized by the X-ray diffraction pattern having characteristic peaks at diffraction angles 29 of approximately 3.5 ± 0.2°, 6.82 ± 0.2°, 11.19 ± 0.2°, 12.22 ± 0.2°, 13.02 ± 0.2°, 16.23 ± 0.2°, 16.91 ± 0.2°, 18.82 ± 0.2°, 24.73 ± 0.2° and 26.89 ± 0.2°.

2. The crystalline Form X of Roxadustat according to claim 1, wherein the X-ray powder diffraction pattern is as shown in FIG. 2.

3. The crystalline Form X of Roxadustat according to claim 1, where in the IR spectrum pattern is as shown in FIG. 4.

4. The crystalline Form X of Roxadustat according to claim 1, where in ’ H-NMR and13C- NMR spectrums are as shown in FIG. 5 and FIG.6.

5. The crystalline Form X of Roxadustat according to claim 1, where in the DSC thermogram pattern is as shown in FIG. 3.

6. A process for the preparation of Roxadustat Form X of any one of Claims 1-5, comprising: a) preparing a sodium or potassium salt of Roxadustat in a solution; b) filtering the solution c) optionally, cooling the solution d) adjusting to pH 5.5-6.5 e) isolating Roxadustat Form X.

7. A process for the preparation of Roxadustat Form X of any one of claims 1-6 comprising the step of crystallizing Roxadustat from solvent or solvent mixtures comprising water, methanol, ethanol or acetone.

8. Use of crystalline Form X of any one of claims 1-7 in manufacturing a medicament comprising Roxadustat.

9. A medicament for the treatment of adult patients with symptomatic anemia associated with chronic kidney disease (CKD) comprising administering a therapeutically effective amount of crystalline Form X of any one of the claims 1 to 8.

Images