Axitinib tartrate crystal form and preparation method thereof

Abstract

This invention belongs to the field of crystalline drug molecule technology, specifically relating to an axitinib tartrate crystal form, its preparation method, and its applications. The axitinib tartrate crystal form provided by this invention achieves significant improvements in solubility and photostability. The preparation method of this crystal form is simple to operate, has good reproducibility, and is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of crystal drug molecular technology, specifically to an axitinib tartrate crystal form and its preparation method. Background Technology

[0002] Axitinib, developed by Pfizer Inc., is a potent and selective inhibitor of vascular endothelial growth factor receptor (VEGFR) / platelet-derived growth factor (PDGFR) receptor tyrosine kinase (RTK) in early to late-stage cancers. It was approved by the FDA on January 27, 2012, and marketed under the brand name [Brand Name Missing]. On April 29, 2015, axitinib was approved by the CFDA for the treatment of adult patients with advanced renal cell carcinoma (RCC) who have failed prior therapy with a tyrosine kinase inhibitor or cytokine. Its chemical name is N-methyl-2-[3-((E)-2-pyridin-2-yl-vinyl)-1H-indole-6-ylsulfonyl]-benzamide, and its structural formula is shown below:

[0003]

[0004] Due to the inherent photosensitivity and poor solubility of axitinib, researchers in the field have been attempting to develop different crystal forms to obtain axitinib crystals more suitable for pharmaceutical use. Patent WO2006048751A1 attempted to study axitinib crystal forms, disclosing multiple crystal forms including crystal form I, crystal form II, crystal form III, crystal form IV, crystal form VI, crystal form VII, and crystal form VIII. However, simply changing the crystal form of axitinib did not significantly improve its solubility. For example, crystal form IV has a solubility of approximately 0.55 mg / ml in an aqueous solution with a pH of approximately 1, only 0.157 mg / ml in an aqueous solution with a pH of approximately 2, and only 2 μg / ml in an aqueous solution with a pH of approximately 6.5. Simultaneously, it was reported that seven axitinib acid salt compounds were prepared to improve the water solubility of axitinib, which improved its solubility, but all of them showed significant degradation upon exposure to high-intensity light, and were all photosensitive axitinib salts. Patent CN200880016453.6 discloses various crystal forms such as 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 inherent photosensitivity and poor solubility of axitinib, researchers have been exploring the development of different crystal forms to obtain more suitable pharmaceutical formulations. However, according to current reports, considering bioavailability, stability, and manufacturability, among the many publicly disclosed axitinib crystal forms, only crystal form IV and crystal form XLI are usable. Furthermore, due to the extreme instability of crystal form IV upon light exposure, Pfizer ultimately chose crystal form XLI, which exhibits relatively lower degradation upon light exposure, as its marketed crystal form (see the CHMP evaluation report). However, as reported by those skilled in the art through patent CN200880016453.6, the potency of the marketed crystal form XLI decreases to 89% after light exposure. To achieve pharmaceutical safety and efficacy, a light-shielding formulation process remains unavoidable. Subsequent developments of axitinib solvate crystal forms, axitinib acid salt crystal forms, and new axitinib crystal forms all still have deficiencies in terms of drug safety, solubility, bioavailability, or photostability.

[0006] For example, patent WO2015067224A1, based on the seven obtainable axitinib acid salt compounds disclosed in patent WO2006048751A1, further characterized the seven axitinib acid salts using powder diffraction data. Patent CN201510509413.7 discloses the preparation of axitinib fumarate crystal form A, in which the molar ratio of axitinib to fumaric acid is 1:1. After light irradiation, the axitinib fumarate degraded by 0.13%. CN202010787156.4 discloses a crystal form B of axitinib fumarate, with a molar ratio of axitinib to fumaric acid of 1:1.5; after 10 days of light irradiation, the appearance and drug content of the axitinib fumarate crystal form B powder sample did not change significantly. However, the water adsorption rate was 1.5% at 95% RH. CN202011575325.4 provides an axitinib maleate crystal form, wherein the molar ratio of axitinib to maleic acid is 1:1, and the basic unit of the crystal form consists of two molecules of axitinib, two molecules of maleic acid, and two molecules of water. CN202011585244.2 provides an axitinib malate crystal form, wherein the basic unit of the malate crystal form consists of one molecule of axitinib, one molecule of malic acid, and one molecule of water. CN202011575299.5 provides an axitinib salicylate crystal form, wherein the basic unit of the salicylate crystal form consists of two molecules of axitinib and two molecules of salicylic acid. CN202011573595.1 provides an axitinib citrate crystal form, wherein the basic unit of the citrate crystal form consists 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 is well known, the crystal form of a drug has a significant impact on the stability, dissolution rate, permeability, and bioavailability of solid drug formulations. An excellent crystal form suitable for preparing solid dosage forms generally needs to meet requirements in terms of stability, dissolution rate, and bioavailability. A novel drug salt form refers to the introduction of a new eutectic substance (CCF) through proton transfer, which self-assembles with the active pharmaceutical ingredient (APT) under hydrogen bonding to form a supramolecular crystal with a fixed stoichiometric ratio. In the preclinical development stage of drugs, new drug development companies often improve the drug's solubility, dissolution rate, permeability, hygroscopicity, stability, bioavailability, and other physicochemical properties by salting the active pharmaceutical ingredient (APT). Compared to nanocrystals, solid dispersants, and novel drug formulation technologies, drug salt forms have significant advantages in improving drug solubility, dissolution rate, permeability, hygroscopicity, stability, and bioavailability.

[0008] To better utilize axitinib salt crystals in synergistic drug therapy, this invention provides a simple and easy-to-operate method for preparing high-purity axitinib tartrate crystals, thereby maximizing the medicinal value of axitinib. Summary of the Invention

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

[0010] The specific technical content of this invention is as follows:

[0011] In a first aspect, the present invention provides an axitinib tartrate crystal form, wherein two molecules of axitinib are combined with three molecules of tartaric acid and six molecules of water to form the basic unit of the crystal form.

[0012] Preferably, the axitinib tartrate crystal form, when subjected to Cu-Kα radiation, exhibits characteristic peaks in its X-ray diffraction pattern (denoted as 2θ) at 20.79±0.2°, 22.61±0.2°, 25.11±0.2°, 29.26±0.2°, 29.72±0.2°, 32.05±0.2°, and 37.52±0.2°.

[0013] Preferably, the axitinib tartrate crystal form, when subjected to Cu-Kα radiation, exhibits characteristic peaks in its 2θ X-ray diffraction pattern at 11.78±0.2°, 17.02±0.2°, 18.87±0.2°, 20.22±0.2°, 20.79±0.2°, 22.61±0.2°, 22.89±0.2°, 25.11±0.2°, 26.97±0.2°, 29.26±0.2°, 29.72±0.2°, 32.05±0.2°, 35.48±0.2°, 35.89±0.2°, 36.69±0.2°, 37.52±0.2°, and 43.98±0.2°.

[0014] Preferably, the axitinib tartrate crystal form, when subjected to Cu-Kα radiation, exhibits characteristic peaks consistent with... Figure 3 The X-ray powder diffraction pattern shown is shown.

[0015] Preferably, the crystallographic parameters of the axitinib tartrate are: monoclinic system, space group P21; and the unit cell parameters are: α = 90°, β = 96.5290(10)°, γ = 90°, cell volume

[0016] Preferably, the axitinib tartrate crystal form exhibits two endothermic peaks in the differential scanning calorimetry (DSC) curve, namely 89.35℃ and 186.83℃.

[0017] The second aspect of this application provides a method for preparing axitinib tartrate crystal form, the specific preparation steps of which include: dissolving axitinib and tartaric acid in solvent A, heating to dissolve, obtaining a transparent solution, cooling and allowing to stand to crystallize, filtering, washing, and vacuum drying to obtain axitinib tartrate crystal form.

[0018] Preferably, solvent A is selected from mixed solvents 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.

[0019] Furthermore, solvent A is selected from formic acid-ethanol-water, formic acid-methanol-water, formic acid-acetone-water, and formic acid-isopropanol-water mixed solvents.

[0020] Preferably, the molar ratio of axitinib to tartaric acid is 1:1.2 to 1.9; preferably, the molar ratio of axitinib to tartaric acid is 1:1.4 to 1.7.

[0021] Preferably, the mass-to-volume ratio of axitinib to solvent A in the system is 2 to 5:1, wherein the mass is expressed in mg and the volume in mL.

[0022] Preferably, the melting and heating temperature is 50–60°C.

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

[0024] Preferably, the crystallization time is 48 to 72 hours.

[0025] Preferably, the drying temperature is 25–30°C and the drying time is 5–9 hours.

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

[0027] Thirdly, the present invention provides a pharmaceutical composition comprising the axitinib tartrate crystal form described herein and other pharmaceutically acceptable components.

[0028] Preferably, the other pharmaceutically acceptable components include other active ingredients, excipients, fillers, etc., that can be used in combination.

[0029] Preferably, the pharmaceutical compositions of the present invention can be prepared by combining the compounds of the present invention with a pharmaceutically acceptable solid or liquid carrier using standard and conventional techniques, and by combining them with pharmaceutically acceptable excipients and formulations to prepare a usable dosage form.

[0030] Preferably, the pharmaceutical composition is a spray, tablet, capsule, powder for injection, liquid for injection, etc.

[0031] The fourth aspect of this application provides the use of axitinib tartrate crystal form as an active ingredient in the preparation of a therapeutic anticancer drug.

[0032] Confirmation of crystal structure

[0033] The axitinib tartrate crystal form provided by this invention was analyzed by X-ray single-crystal diffraction. The X-ray single-crystal diffraction instrument and testing conditions involved in this invention were: Rigaku XtaLAB Synergy X-ray single-crystal diffractometer, testing temperature 293(2)K, CuKa radiation, data collected in ω-scan mode and Lp correction performed. The structure was resolved by direct method, all non-hydrogen atoms were identified by difference Fourier method, and all hydrogen atoms on carbon and nitrogen were obtained by theoretical hydrogenation. The structure was refined by least squares method.

[0034] The crystallographic data obtained from testing and analyzing the axitinib tartrate crystal form prepared in this invention are shown in Table 1: its crystallographic parameters are: monoclinic system, space group P21; cell parameters are: α = 90°, β = 96.5290(10)°, γ = 90°, cell volume The ORTEP of the axitinib tartrate crystal form of the present invention Figure 1 This indicates that two molecules of axitinib are bound to three molecules of tartaric acid and six molecules of water. A packing diagram of the axitinib tartrate crystal form of this invention is attached. Figure 2 As shown.

[0035] Table 1. Main crystallographic data of axitinib tartrate crystal forms

[0036]

[0037]

[0038] The X-ray powder diffraction testing instrument and testing conditions involved in this 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; Solar slit: 0.04rad; step size: 0.5s; scanning range: 3~50°.

[0039] Based on the above crystallographic data, the characteristic peaks in the corresponding X-ray powder diffraction pattern (Cu-Kα) are detailed below. Figure 3 And Table 2.

[0040] Table 2 PXRD peaks of axitinib tartrate crystal forms

[0041]

[0042]

[0043] The TGA / DSC thermal analysis instrument and test conditions in this invention are as follows: TGA / DSC thermal analyzer: METTLER TOLEDOTGA / DSC3+; dynamic temperature range: 30~300℃; heating rate: 10℃ / mIVn; programmed gas N2; gas flow rate: 50mL / mIVn; crucible: 40μl aluminum crucible.

[0044] The TGA / DSC test results of the axitinib tartrate crystal form prepared by the method of the present invention are as follows: Figure 4 As shown, the DSC detection results show two endothermic peaks, corresponding to temperatures of 89.35℃ and 186.83℃, respectively. The TGA detection results indicate the presence of two weight loss steps; the first step indicates the crystal contains six water molecules. Combined with the DSC / TGA results, the crystal form prepared in this invention is axitinib tartrate.

[0045] All samples prepared in the examples have the same crystallographic parameters and X-ray powder diffraction patterns as described above.

[0046] The axitinib tartrate crystal form provided by this invention achieves significant improvements in stability, solubility, and permeability. After long-term photostability testing, the tartrate exhibits good photostability. This axitinib tartrate crystal form is regular, with uniform particle size, well-defined crystallographic parameters, and precise atomic spatial positions. Furthermore, the preparation method is simple and suitable for industrial production and large-scale application. Attached Figure Description

[0047] Figure 1 ORTEP diagram of axitinib tartrate crystal form.

[0048] Figure 2 Stacking diagram of axitinib tartrate crystals.

[0049] Figure 3 X-ray powder diffraction pattern of axitinib tartrate crystal form.

[0050] Figure 4 DSC-TGA image of axitinib tartrate crystal form. Detailed Implementation

[0051] The present invention will be further illustrated by the following embodiments. It should be understood that the embodiments of the present invention are merely for illustrating the present invention and are not intended to limit the present invention. Therefore, any simple improvements to the present invention under the premise of the method of the present invention are within the scope of protection claimed by the present invention.

[0052] 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 existing technology or purchased; other materials used in this experiment whose source and specifications are not specified are all commercially available analytical grade or chemically pure.

[0053] Example 1

[0054] 409 mg of axitinib and 258 mg of tartaric acid were added to a mixed solvent of 20 mL formic acid, 50 mL ethanol and 40 mL water. The mixture was heated to 60 °C and stirred to dissolve. The mixture was refluxed for 3 hours, then slowly cooled to 10–20 °C and allowed to stand for crystallization for 48 hours. The crystals were filtered, washed with ethanol, and dried under vacuum at 30 °C for 6 hours to obtain axitinib tartrate crystals with a yield of 95.00% and a purity of 99.79%.

[0055] Example 2

[0056] 773 mg axitinib and 478 mg tartaric acid were added to a mixed solvent of 40 mL formic acid, 80 mL methanol and 80 mL water. The mixture was heated to 60 °C and stirred to dissolve. The mixture was refluxed for 3 hours, then slowly cooled to 10–20 °C and allowed to stand for crystallization for 36 hours. The crystals were filtered, washed with methanol, and dried under vacuum at 25 °C for 6 hours to obtain axitinib tartrate crystals with a yield of 94.86% and a purity of 99.75%.

[0057] Example 3

[0058] 382 mg of axitinib and 235 mg of tartaric acid were added to a mixed solvent of 20 mL formic acid, 40 mL acetone and 40 mL water. The mixture was heated to 55 °C and stirred to dissolve. The mixture was refluxed for 3 hours, then slowly cooled to 10–20 °C and allowed to stand for crystallization for 36 hours. The crystals were filtered, washed with acetone, and dried under vacuum at 25 °C for 6 hours to obtain axitinib tartrate crystals with a yield of 92.10% and a purity of 99.73%.

[0059] Example 4

[0060] 484 mg of axitinib and 291 mg of tartaric acid were added to a mixed solvent of 20 mL formic acid, 40 mL isopropanol and 40 mL water. The mixture was heated to 60 °C and stirred to dissolve. The mixture was refluxed for 3 hours, then slowly cooled to 10–20 °C and allowed to stand for crystallization for 36 hours. The crystals were filtered, the filter cake was washed with isopropanol, and dried under vacuum at 25 °C for 6 hours to obtain axitinib tartrate crystals with a yield of 91.96% and a purity of 99.72%.

[0061] Verification Example:

[0062] This invention investigated the stability, hygroscopicity, solubility, and permeability of the prepared axitinib crystal form, and the specific implementation details are as follows:

[0063] 1. Light stability test

[0064] The crystal form obtained in Example 1 was stored at 25°C (RH 45%) under strong light irradiation (4500 Lx ± 500 Lx). Samples were taken at 5 and 10 days, and the purity was determined by HPLC. The results are shown in Table 3.

[0065] Table 3 Results of photostability tests on axitinib crystal forms

[0066]

[0067] Photostability tests showed that the axitinib tartrate crystal form prepared in this invention exhibited good photostability after 10 days of strong light irradiation. Further investigation revealed similar stability test results for Examples 1-4.

[0068] 2. Hygroscopicity test

[0069] Hygroscopicity tests were conducted on the axitinib tartrate crystal form obtained in Example 1, the axitinib fumarate crystal form B in CN202010787156.4 (obtained by repeating Example 1), and the axitinib maleate crystal form in CN202011575325.4 (obtained by repeating Example 1).

[0070] The methods and conditions for hygroscopicity testing shall refer to the Guidelines for Hygroscopicity Testing of Drugs in Part IV, General Chapter 9103 of the 2020 edition of the Chinese Pharmacopoeia.

[0071] Among them, the description of hygroscopic characteristics and the definition of hygroscopic weight gain are as follows:

[0072] Deliquescence: The process of absorbing sufficient water to form a liquid.

[0073] Extremely hygroscopic: the weight gain due to moisture absorption is not less than 15%.

[0074] It has hygroscopic properties: the weight gain due to moisture absorption is less than 15% but not less than 2%.

[0075] Slightly hygroscopic: the weight gain due to moisture absorption is less than 2% but not less than 0.2%.

[0076] It has little or no hygroscopicity: the weight gain due to moisture absorption is less than 0.2%.

[0077] The results of the hygroscopicity test are shown in Table 4.

[0078] Table 4 Results of Hygroscopicity Test

[0079]

[0080] Conclusion: The axitinib tartrate crystal form obtained in this invention is hygroscopic and easily deliquesces due to high humidity. Humidity control is necessary for long-term storage of this drug form. PXRD analysis of the hygroscopic crystal forms showed that each crystal form remained stable. Furthermore, thermal stability studies revealed that temperatures above 35°C resulted in the loss of water of crystallization, affecting stability. Low-temperature storage is required.

[0081] 3. Solubility test

[0082] Test method: Water, 0.01 mol / L hydrochloric acid solution, and pH 6.8 PBS buffer were used as media. Excess of the cocrystal obtained in Example 1 was added to each of the above media, and the mixture was stirred at 37°C for 72 hours. Sampling was repeated three times, filtered, and an appropriate amount of the filtrate was diluted. The solubility in each medium was determined by HPLC.

[0083] Table 5. Solubility of axitinib in different media (mg / ml)

[0084]

[0085] Solubility test results show that the axitinib tartrate crystal form prepared by this invention exhibits significantly improved solubility compared to the available crystal forms disclosed in the prior art. Further investigation revealed similar solubility test results for Examples 1-4.

[0086] 4. Permeability test

[0087] Test conditions: Permeability test was conducted using the Franz diffusion cell method at a water temperature of (37±0.5)℃.

[0088] Dialysis membrane (model: MW 14000Da, Himedia, India): treated with 10% sodium bicarbonate solution, 10Mm EDTA solution, and deionized water at 70℃ for 20 min respectively; the treated dialysis membrane was then loaded into a diffusion cell (effective surface area 4.15 cm²). 2 In the donor chamber, crystal form B of axitinib fumarate (prepared in repetition of Example 1) (10 mg based on axitinib) from Example 1 and CN202010787156.4 was suspended in 2 ml of distilled water; the recipient chamber was filled with phosphate buffer (pH = 7.4), kept at room temperature, and the bubbles were removed and the mixture was magnetically stirred at 45 ± 5 RPM; the cumulative permeation was tested after 24 hours.

[0089] Table 6. Cumulative osmotic volume of axitinib (mg / cm³) 2 )

[0090] sample <![CDATA[Penetration cumulative amount (mg / cm 2 )]]> Example 1 0.3869 Axitinib fumarate crystal form B 0.1897

Claims

1. An axitinib tartrate crystal form, characterized in that, The basic unit of the axitinib tartrate crystal form consists of two molecules of axitinib combined with three molecules of tartaric acid and six molecules of water. The crystal form, when subjected to Cu-Kα radiation, exhibits characteristic peaks in its 2θ X-ray diffraction pattern at 11.78 ± 0.2°, 17.02 ± 0.2°, 18.87 ± 0.2°, 20.22 ± 0.2°, 20.79 ± 0.2°, 22.61 ± 0.2°, 22.89 ± 0.2°, 25.11 ± 0.2°, 26.97 ± 0.2°, 29.26 ± 0.2°, 29.72 ± 0.2°, 32.05 ± 0.2°, 35.48 ± 0.2°, 35.89 ± 0.2°, 36.69 ± 0.2°, 37.52 ± 0.2°, and 43.98 ± 0.2°. The crystallographic parameters of the described crystal form are: monoclinic crystal system, space group . P2 1 The unit cell parameters are: a = 7.57220(10) Å, b = 29.9306(6)Å, c = 14.8746(2)Å, α =90°, β =96.5290(10)°, γ =90°, unit cell volume V =3349.32(9)Å 3 .

2. The axitinib tartrate crystal 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 Figure 3.

3. The method for preparing the axitinib tartrate crystal form according to any one of claims 1-2, characterized in that, The steps include: dissolving axitinib and tartaric acid in solvent A, heating to dissolve, obtaining a transparent solution, cooling and allowing to stand to crystallize, filtering, washing, and vacuum drying to obtain axitinib tartrate crystals; The solvent A is selected from the mixed solvents 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; The cooling and crystallization temperature is 0–30°C.

4. The preparation method according to claim 3, characterized in that, The molar ratio of axitinib to tartaric acid is 1:1.2 to 1.

9.

5. The preparation method according to claim 3, characterized in that, The molar ratio of axitinib to tartaric acid is 1:1.4 to 1.

7.

6. The preparation method according to claim 3, characterized in that, The melting and heating temperature is 50-60℃; the cooling and crystallization temperature is 10-20℃.

7. The use of the axitinib tartrate crystal form according to any one of claims 1-2 as an active ingredient in the preparation of antitumor drugs.

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