Axitinib oxalate crystal form and preparation method thereof

Abstract

The invention belongs to the technical field of crystal form medicine molecules, and particularly relates to an axitinib oxalate crystal form as well as a preparation method and application thereof. According to the axitinib oxalate crystal form provided by the invention, a basic unit of the crystal form is formed by combining one molecule of axitinib with one molecule of oxalic acid and two molecules of water, the solubility is high, the stability is good, the preparation method is simple to operate, the reproducibility is good, and the axitinib oxalate crystal form is suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of crystalline drug molecules, and in particular to an axitinib oxalate crystalline form and a preparation method thereof. Background Art

[0002] Axitinib is a potent and selective inhibitor of vascular endothelial growth factor receptor (VEGFR) / platelet-derived growth factor (PDGFR) receptor tyrosine kinase (RTK) developed by Pfizer, USA, for inhibiting early to late stage cancer. It was approved for marketing by the US FDA on January 27, 2012, with the trade name of On April 29, 2015, Axitinib was approved by CFDA for use in adult patients with advanced renal cell carcinoma (RCC) who have failed treatment with a tyrosine kinase inhibitor or cytokine. Its chemical name is: N-methyl-2-[3-((E)-2-pyridin-2-yl-vinyl)-1H-indol-6-ylsulfonyl]-benzamide, and its structural formula is as follows:

[0003]

[0004] Due to the many problems of photosensitivity and poor solubility of axitinib itself, people in this field are trying to develop different crystal forms to obtain axitinib crystal forms that are more suitable for pharmaceutical use. Patent WO2006048751A1 attempts to study axitinib crystal forms, and discloses axitinib crystal forms I, II, III, IV, VI, VII and VIII, but simply changing the axitinib crystal form does not significantly improve its solubility. For example, the solubility of crystal form IV in an aqueous solution with a pH of about 1 is about 0.55 mg / ml, in an aqueous solution with a pH of about 2, the solubility is only 0.157 mg / ml, and in an aqueous solution with a pH of about 6.5, the solubility is only 2 μg / ml; at the same time, it is reported that in order to improve the water solubility of axitinib, 7 axitinib acid salt compounds were prepared, and their solubility was improved, but they were significantly degraded when exposed to high-intensity light, and all of them were photosensitive axitinib salts. Patent CN200880016453.6 discloses multiple crystal forms including crystal form XXV, crystal form XVI, crystal form XLI, crystal form IX, crystal form XII and crystal form XV. Crystal form XXV and crystal form XLI have not been significantly improved in terms of solubility and bioavailability.

[0005] Due to the many problems of photosensitivity and poor solubility of axitinib itself, people in this field are trying to develop different crystal forms to obtain axitinib crystal forms that are more suitable for pharmaceutical use. However, according to current reports, from the perspective of bioavailability, stability and manufacturability, among the many publicly available axitinib crystal forms, only crystal form IV and crystal form XLI are available. Due to the extreme instability of crystal form IV under light exposure, the original Pfizer company finally selected crystal form XLI with relatively less light exposure degradation as the marketed crystal form (see CHMP evaluation report). However, those skilled in the art know from the report of patent CN200880016453.6 that the potency of marketed crystal form XLI after light exposure is reduced to 89%. In order to achieve pharmaceutical safety and effectiveness, the preparation process using the light shielding process is still inevitable. However, some subsequent developments and studies of axitinib solvate crystal forms, axitinib salt crystal forms, and axitinib new crystal forms still have defects in drug safety, solubility, bioavailability or photostability.

[0006] For example, patent WO2015067224A1 further characterized 7 axitinib acid salts by powder diffraction data based on the 7 available axitinib acid salt compounds disclosed in patent WO2006048751A1. Patent CN201510509413.7 discloses the preparation of a crystalline form A of axitinib fumarate, in which the molar ratio of axitinib to fumaric acid is 1:1. After irradiation with light, axitinib fumarate degraded by 0.13%. CN202010787156.4 discloses a crystalline form B of axitinib fumarate, in which the molar ratio of axitinib to fumaric acid is 1:1.5; the axitinib fumarate crystalline form B powder sample was irradiated for 10 days, and the appearance and drug content did not change significantly. However, the water adsorption rate was 1.5% at 95% RH. CN202011575325.4 provides a crystal form of axitinib maleate, in which the molar ratio of axitinib to maleic acid is 1:1, and two molecules of axitinib, two molecules of maleic acid, and two molecules of water constitute the basic unit of the crystal form. CN202011585244.2 provides a crystal form of axitinib malate, in which the basic unit of the malate crystal form is composed of one molecule of axitinib, one molecule of malic acid, and one molecule of water. CN202011575299.5 provides a crystal form of axitinib salicylate, in which the basic unit of the salicylate crystal form is composed of two molecules of axitinib and two molecules of salicylic acid. CN202011573595.1 provides a crystal form of axitinib citrate, in which the basic unit of the citrate crystal form is composed of one molecule of axitinib, one molecule of citric acid, and one molecule of water. These axitinib salts have achieved beneficial effects in terms of stability, solubility, and permeability.

[0007] As we all know, the crystal form of the drug has a great influence on the stability, solubility, permeability, bioavailability, etc. of the solid drug preparation. The excellent crystal form suitable for the preparation of solid preparations generally needs to meet various requirements such as stability, solubility, and bioavailability. A new salt form of a drug refers to a new eutectic substance (CCF) introduced by proton transfer, which self-assembles with the active pharmaceutical ingredient (APT) under the action of hydrogen bonds to form a supramolecular crystal with a fixed stoichiometric ratio. In the preclinical drug development stage, new drug development companies usually use the active pharmaceutical ingredient (APT) to improve the drug's solubility, dissolution rate, permeability, hygroscopicity, stability, bioavailability, and other physical and chemical properties by salting. Compared with nanocrystals, solid dispersants, and new drug dosage form technologies, drug salt forms have obvious advantages in improving drug solubility, dissolution rate, permeability, hygroscopicity, stability, and bioavailability.

[0008] In order to better utilize axitinib salt crystals in drug synergistic therapy, the present invention provides a simple and easy-to-operate method for preparing high-purity axitinib oxalate crystals, thereby more efficiently exerting the medicinal value of axitinib. Summary of the invention

[0009] In view of the deficiencies in the prior art, an object of the present invention is to provide axitinib oxalate crystalline form and a preparation method thereof; the salt has definite main crystallographic parameters and atomic spatial positions; and has achieved significant improvements in stability, solubility, permeability, etc.

[0010] The specific technical contents of the present invention are as follows:

[0011] In a first aspect, the present invention provides an axitinib oxalate crystalline form, in which one molecule of axitinib is combined with one molecule of oxalic acid and two molecules of water to form a basic unit of the crystalline form.

[0012] Preferably, the axitinib oxalate crystalline form uses Cu-Kα radiation, and the X-ray diffraction spectrum expressed as 2θ has characteristic peaks at 7.17±0.2°, 17.21±0.2°, 18.07±0.2°, 20.47±0.2°, and 24.76±0.2°.

[0013] Preferably, the axitinib oxalate crystalline form uses Cu-Kα radiation, and the X-ray diffraction spectrum expressed as 2θ has characteristic peaks at 7.17±0.2°, 11.25±0.2°, 12.42±0.2°, 14.13±0.2°, 17.21±0.2°, 18.07±0.2°, 18.52±0.2°, 20.47±0.2°, 21.60±0.2°, 23.45±0.2°, 24.76±0.2°, 27.32±0.2°, 28.16±0.2°, and 30.39±0.2°.

[0014] Preferably, the characteristic peaks of the axitinib oxalate crystalline form, using Cu-Kα radiation, meet the following conditions: Figure 3 The X-ray powder diffraction pattern is shown.

[0015] Preferably, the crystallographic parameters of the axitinib oxalate crystalline form are: triclinic system, space group P-1; unit cell parameters are: α=66.9690(10)°,β=76.9010(10)°,γ=84.3290(10)°,unit cell volume

[0016] The second aspect of the present application provides a method for preparing axitinib oxalate crystalline form, and the specific preparation steps include: dissolving axitinib and oxalic acid in solvent A, heating to dissolve to obtain a transparent solution, cooling and standing to crystallize, filtering, washing, and vacuum drying to obtain axitinib oxalate crystalline form.

[0017] Preferably, the solvent A is selected from a mixed solvent of acetic acid-methanol-water, acetic acid-ethanol-water, acetic acid-acetone-water, acetic acid-isopropanol-water, formic acid-methanol-water, formic acid-ethanol-water, formic acid-acetone-water and formic acid-isopropanol-water.

[0018] Further preferably, the solvent A is selected from a mixed solvent of formic acid-ethanol-water, formic acid-methanol-water, formic acid-acetone-water, and formic acid-isopropanol-water.

[0019] Preferably, the volume ratio of acid, alcohol or acetone, and water in the solvent A mixed solvent is 1:1-5:0.5-5, preferably 1:2.5:1.

[0020] Preferably, the molar ratio of axitinib to oxalic acid is 1:1.0 to 1.4; preferably, the molar ratio of axitinib to oxalic acid is 1:1.0 to 1.2.

[0021] Preferably, the mass-to-volume ratio of axitinib to solvent A in the system is 3-6:1, wherein the mass is measured in mg and the volume is measured in mL.

[0022] Preferably, the dissolving and heating temperature is 55-70°C.

[0023] Preferably, the cooling and crystallization temperature is 0-30°C, preferably, the cooling and crystallization temperature is 10-20°C.

[0024] Preferably, the crystallization time is 36 to 72 hours.

[0025] Preferably, the drying temperature is 55-60° C., and the drying time is 5-10 hours.

[0026] Preferably, the solvent for washing the filter cake is selected from one of ethanol, methanol, acetone and isopropanol.

[0027] The third aspect of the present invention provides a pharmaceutical composition, comprising the axitinib oxalate crystalline form prepared as described above, mixed with other components.

[0028] Preferably, the pharmaceutical composition of the present invention is prepared by combining the compound of the present invention with a pharmaceutically acceptable solid or liquid carrier and optionally with a pharmaceutically acceptable excipient to prepare a usable dosage form using standard and conventional techniques.

[0029] Preferably, the other components include other active ingredients, fillers, diluents, binders, disintegrants, lubricants, etc. that can be used in combination.

[0030] Preferably, the diluent is selected from one or more of starch, sucrose, dextrin, lactose, microcrystalline cellulose, mannitol, and sorbitol; the binder is selected from one or more of methylcellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose, sodium hydroxymethyl cellulose, ethyl cellulose, and povidone; the disintegrant is selected from one or more of sodium carboxymethyl starch, low-substituted hydroxypropyl cellulose, cross-linked sodium carboxymethyl cellulose, and cross-linked povidone; the lubricant is selected from one or more of magnesium stearate, micropowdered silica gel, talc, and sodium lauryl sulfate.

[0031] Preferably, the pharmaceutical composition is in the form of tablets, capsules, granules and pills.

[0032] The fourth aspect of the present application provides a use of axitinib oxalate crystalline form as an active ingredient in the preparation of therapeutic anticancer drugs.

[0033] Confirmation of crystal structure

[0034] The axitinib oxalate crystalline form provided by the present invention is subjected to X-ray single crystal diffraction test and analysis. The X-ray single crystal diffraction instrument and test conditions involved in the present invention are: Rigaku XtaLAB Synergy X-ray single crystal diffractometer, test temperature 293 (2) K, CuKa radiation, ω scanning mode data collection and Lp correction. The structure is analyzed by direct method, the difference Fourier method is used to find all non-hydrogen atoms, all hydrogen atoms on carbon and nitrogen are obtained by theoretical hydrogenation, and the structure is refined by least squares method.

[0035] The crystallographic data obtained by testing and analyzing the axitinib oxalate crystalline form prepared by the present invention are (Table 1): Its crystallographic parameters are: triclinic system, space group is P-1; unit cell parameters are: α=66.9690(10)°,β=76.9010(10)°,γ=84.3290(10)°,unit cell volume ORTEP of the axitinib oxalate crystalline form of the present invention Figure 1 It shows that one molecule of axitinib is combined with one molecule of oxalic acid and two molecules of water. The stacking diagram of the axitinib oxalate crystalline form of the present invention is shown in the attached Figure 2 shown.

[0036] Table 1 Main crystallographic data of axitinib oxalate

[0037]

[0038]

[0039] The X-ray powder diffraction test instrument and test conditions involved in the present invention are as follows: X-ray powder diffractometer: PANalytIIcal E; Cu-Kα; sample stage: flat plate; incident light path: BBHD; diffraction light path: PLXCEL; voltage 45kv, current 40mA; divergence slit: 1 / 4; anti-scattering slit: 1; Soller slit: 0.04rad; step size: 0.5s; scanning range: 3-50°.

[0040] According to the above crystallographic data, the corresponding characteristic peaks in the X-ray powder diffraction pattern (Cu-Kα) are shown in Figure 3 And Table 2.

[0041] Table 2 PXRD peak data of axitinib oxalate crystalline form

[0042]

[0043] All samples prepared in the examples have the same crystallographic parameters and X-ray powder diffraction spectra as described above.

[0044] The axitinib oxalate crystalline form provided by the present invention has achieved significant improvements in stability, solubility, permeability, etc. After long-term photostability inspection, the co-crystal has good photostability. The axitinib oxalate crystalline form is regular, has uniform particle size, has clear main crystallographic parameters and exact atomic spatial positions, and has a simple preparation method, which is suitable for industrial production and large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 : ORTEP diagram of axitinib oxalate crystalline form.

[0046] Figure 2 : Stacking diagram of axitinib oxalate crystalline form.

[0047] Figure 3 : X-ray powder diffraction pattern of axitinib oxalate crystalline form. DETAILED DESCRIPTION

[0048] The present invention is further illustrated by the following examples. It should be correctly understood that the examples of the present invention are only used to illustrate the present invention, rather than to limit the present invention. Therefore, simple improvements to the present invention based on the method of the present invention are all within the scope of protection claimed by the present invention.

[0049] Materials used in the experiment: Axitinib can be purchased or prepared according to the method disclosed in patent WO2006048745. The axitinib crystal form required for the comparative experiment can be prepared according to the existing technology or purchased; the materials used in other experiments without indicating the source and specification are all commercially available analytically pure or chemically pure.

[0050] Example 1

[0051] 399 mg of axitinib and 101 mg of oxalic acid were added to a mixed solvent of 20 mL of formic acid, 50 mL of ethanol and 10 mL of water, heated to 70°C and stirred to dissolve, refluxed for 3 hours, slowly cooled to 10-20°C, and then allowed to stand for crystallization for 36 hours under controlled temperature, filtered, and the filter cake was washed with ethanol, and vacuum dried at 55°C for 6 hours to obtain axitinib oxalate crystals with a yield of 98.00% and a purity of 99.80%.

[0052] Example 2

[0053] 451 mg of axitinib and 154 mg of oxalic acid were added to a mixed solvent of 20 mL of formic acid, 50 mL of methanol and 10 mL of water, heated to 65°C with stirring to dissolve, refluxed for 3 hours, slowly cooled to 10-20°C, and then allowed to stand at a controlled temperature for crystallization for 36 hours. The mixture was filtered, the filter cake was washed with methanol, and vacuum dried at 55°C for 6 hours to obtain axitinib oxalate crystals with a yield of 97.26% and a purity of 99.75%.

[0054] Example 3

[0055] 351 mg of axitinib and 82 mg of oxalic acid were added to a mixed solvent of 20 mL of formic acid, 40 mL of acetone and 20 mL of water, heated to 60°C and stirred to dissolve, refluxed for 3 hours, slowly cooled to 10-20°C, and then allowed to stand for crystallization for 36 hours under controlled temperature, filtered, and the filter cake was washed with acetone, and vacuum dried at 55°C for 6 hours to obtain axitinib oxalate crystals with a yield of 95.11% and a purity of 99.81%.

[0056] Example 4

[0057] 383 mg of axitinib and 95 mg of oxalic acid were added to a mixed solvent of 20 mL of formic acid, 40 mL of isopropanol and 20 mL of water, heated to 65°C with stirring to dissolve, refluxed for 3 hours, slowly cooled to 10-20°C, and then allowed to stand for crystallization for 36 hours under controlled temperature, filtered, and the filter cake was washed with isopropanol, and vacuum dried at 55°C for 6 hours to obtain axitinib oxalate crystals with a yield of 94.95% and a purity of 99.74%.

[0058] Verification example:

[0059] The present invention investigates the above-prepared axitinib crystal form in terms of stability, hygroscopicity, solubility, permeability, etc. The specific implementation contents are as follows:

[0060] 1. Photostability test

[0061] The crystal form obtained in Example 1 was stored at 25°C (RH 45%) under strong light irradiation (4500 Lx±500 Lx), and samples were taken after 5 days and 10 days, and the purity was tested by HPLC. The results are shown in Table 3.

[0062] Table 3 Results of photostability test of axitinib crystals

[0063]

[0064] The results of the photostability test show that after 10 days under strong light irradiation, the axitinib oxalate crystalline form prepared by the present invention has good photostability. It is found that Examples 1 to 4 have similar stability test results.

[0065] 2. Moisture absorption test

[0066] The axitinib oxalate crystalline form obtained in Example 1, the axitinib fumarate crystalline form B in CN202010787156.4 (prepared by repeating Example 1), and the axitinib maleate crystalline form in CN202011575325.4 (prepared by repeating Example 1) were used for hygroscopicity test.

[0067] The hygroscopicity test method and conditions refer to the Chinese Pharmacopoeia 2020 Edition Part IV General Principles 9103 Guiding Principles for Drug Hygroscopicity Test

[0068] Among them, the description of hygroscopic characteristics and the definition of hygroscopic weight gain are:

[0069] Deliquescent: Absorbs sufficient water to form a liquid.

[0070] Highly hygroscopic: weight gain due to moisture absorption is not less than 15%.

[0071] Hygroscopic: Weight gain due to moisture absorption is less than 15% but not less than 2%.

[0072] Slightly hygroscopic: weight gain due to moisture absorption is less than 2% but not less than 0.2%.

[0073] No or almost no hygroscopicity: moisture gain is less than 0.2%.

[0074] The results of the hygroscopicity test are shown in Table 4.

[0075] Table 4 Hygroscopicity investigation results

[0076]

[0077] Conclusion: The axitinib oxalate crystals obtained by the present invention are slightly hygroscopic and need to be stored under controlled humidity. In addition, PXRD was performed on the crystals after moisture absorption to test whether each crystal was stable.

[0078] 3. Solubility test

[0079] Test method: Take water, 0.01 mol / L hydrochloric acid solution, and pH 6.8 PBS buffer as the medium, take an excess of the axitinib oxalate crystal obtained in Example 1, add it to the above medium, and stir at 37°C for 72 hours. Repeat the sampling three times, filter, take an appropriate amount of the filtrate, dilute, and use HPLC to detect the solubility in each medium.

[0080] Table 5 Solubility of Axitinib in different media (mg / ml)

[0081]

[0082] The solubility test results show that the solubility of the axitinib oxalate crystalline form prepared by the present invention has been significantly improved compared with the available crystalline form disclosed in the prior art. Oxalic acid, as a medium-strong acid, promotes the solubility of axitinib. It was found that Examples 1 to 4 had similar solubility test results.

[0083] 4. Permeability test

[0084] Test conditions: The permeability test was carried out using the Franz diffusion cell method at a water temperature of (37±0.5)℃.

[0085] Dialysis membrane (model: MW 14000Da, Himedia, India): treated with 10% sodium bicarbonate solution, 10 MmEDTA solution, and deionized water at 70 °C for 20 min respectively; the treated dialysis membrane was placed in a diffusion cell (effective surface area 4.15 cm 2 ); the donor chamber was respectively taken from Example 1 and CN202010787156.4, the crystal form B of axitinib fumarate (prepared by repeating Example 1) (based on the amount of axitinib, 10 mg) and suspended in 2 ml of distilled water; the receptor chamber was filled with phosphate buffer (pH = 7.4), maintained at room temperature, bubbles were removed, and magnetic stirring was performed at 45 ± 5 RPM; the cumulative permeation amount was tested after 24 hours.

[0086] Table 6 Cumulative permeation of axitinib (mg / cm 2 )

[0087]

[0088]

Claims

1. A crystalline form of axitinib oxalate, characterized in that: The basic unit of the axitinib oxalate crystalline form is composed of one molecule of axitinib combined with one molecule of oxalic acid and two molecules of water.

2. The axitinib oxalate crystalline form according to claim 1, characterized in that: Using Cu-Kα radiation, the X-ray diffraction spectrum expressed in 2θ has characteristic peaks at 7.17±0.2°, 17.21±0.2°, 18.07±0.2°, 20.47±0.2°, and 24.76±0.2°.

3. The axitinib oxalate crystalline form according to claim 1, characterized in that: Using Cu-Kα radiation, the X-ray diffraction spectrum expressed in 2θ has characteristic peaks at 7.17±0.2°, 11.25±0.2°, 12.42±0.2°, 14.13±0.2°, 17.21±0.2°, 18.07±0.2°, 18.52±0.2°, 20.47±0.2°, 21.60±0.2°, 23.45±0.2°, 24.76±0.2°, 27.32±0.2°, 28.16±0.2°, and 30.39±0.2°.

4. The axitinib oxalate crystalline form according to claim 1, characterized in that: Using Cu-Kα radiation, its characteristic peaks conform to the X-ray powder diffraction pattern shown in FIG3 .

5. The axitinib oxalate crystalline form according to claim 1, characterized in that: Its crystallographic parameters are: triclinic system, space group is P-1; unit cell parameters are: α=66.9690(10)°,β=76.9010(10)°,γ=84.3290(10)°,unit cell volume 6. The method for preparing the axitinib oxalate crystalline form according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: dissolving axitinib and oxalic acid in solvent A, heating to dissolve to obtain a transparent solution, cooling and standing to crystallize, filtering, washing, and vacuum drying to obtain axitinib oxalate crystal form.

7. The preparation method according to claim 6, characterized in that: The solvent A is selected from a mixed solvent of acetic acid-methanol-water, acetic acid-ethanol-water, acetic acid-acetone-water, acetic acid-isopropanol-water, formic acid-methanol-water, formic acid-ethanol-water, formic acid-acetone-water and formic acid-isopropanol-water.

8. The preparation method according to claim 6, characterized in that: The molar ratio of axitinib to oxalic acid is 1:1.0 to 1.4; preferably, the molar ratio of axitinib to oxalic acid is 1:1.0 to 1.

2.

9. The preparation method according to claim 6, characterized in that The dissolving and heating temperature is 55-70°C; the cooling and crystallizing temperature is 0-30°C, preferably, the cooling and crystallizing temperature is 10-20°C.

10. Use of the axitinib oxalate crystal form according to any one of claims 1 to 5 as an active ingredient in the preparation of anti-tumor drugs.

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