Axitinib cocrystal and preparation method thereof

Abstract

This invention belongs to the field of crystalline drug molecule technology, specifically relating to a method for preparing and applying axitinib-fumaric acid-acetic acid cocrystal. The axitinib-fumaric acid-acetic acid cocrystal provided by this invention comprises one molecule of axitinib, one molecule of fumaric acid, and one molecule of acetic acid as its basic crystalline unit. It exhibits significant improvements in stability, solubility, and permeability. The preparation method is simple to operate, has good reproducibility, and is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of crystalline drug molecule technology, specifically to a method for preparing and applying axitinib-fumaric acid-acetic acid cocrystal. 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 novel 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. Beneficial effects have been achieved in terms of stability, solubility, and permeability.

[0007] Statistics show that over 40% of drug candidates fail to enter clinical trials due to poor water solubility, poor permeability, and low bioavailability. For these poorly soluble drugs, cocrystallization technology has received considerable attention in recent years for addressing this issue. Cocrystallization is an important form of multi-component drug crystals, referring to crystals formed by the bonding of a drug (API) with a pharmaceutically acceptable small-molecule ligand copolymer (CCF), which is solid at room temperature, through non-covalent bonds such as hydrogen bonds, van der Waals forces, π-π stacking interactions, and halogen bonds, in a fixed stoichiometric ratio. Cocrystallization technology is a novel technique that improves the physicochemical properties of drug molecules, such as stability, solubility, permeability, and bioavailability, without altering the drug's molecular structure, thus enhancing its drug-likeness. For example, studies have reported that cocrystallization of the flavonoid quercetin with caffeine, theobromine, and isonicotinamide resulted in a 2.5–10-fold increase in bioavailability.

[0008] To better leverage the synergistic therapeutic effects of axitinib with fumaric acid or maleic acid crystal forms, this invention provides a simple and easy-to-operate method for preparing high-purity axitinib-fumaric acid-acetic acid co-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 an axitinib-fumaric acid-acetic acid eutectic; the eutectic 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-fumaric acid-acetic acid eutectic, wherein one molecule of axitinib, one molecule of fumaric acid, and one molecule of acetic acid constitute the basic unit of the crystal form.

[0012] Preferably, the axitinib-fumarate-acetic acid eutectic, when irradiated with Cu-Kα, exhibits characteristic peaks in its 2θ X-ray diffraction pattern at 23.06±0.2°, 25.80±0.2°, 29.04±0.2°, 29.67±0.2°, 38.21±0.2°, and 38.89±0.2°.

[0013] Preferably, the axitinib-fumaric acid-acetic acid eutectic, when subjected to Cu-Kα radiation, exhibits characteristic peaks in its 2θ X-ray diffraction pattern at 7.08±0.2°, 14.65±0.2°, 16.23±0.2°, 18.25±0.2°, 20.97±0.2°, 23.06±0.2°, 24.97±0.2°, 25.80±0.2°, 27.04±0.2°, 29.04±0.2°, 29.67±0.2°, 38.21±0.2°, and 38.89±0.2°.

[0014] Preferably, the axitinib-fumaric acid-acetic acid eutectic, when subjected to Cu-Kα radiation, exhibits characteristic peaks that conform to... Figure 1 The X-ray powder diffraction patterns and detection data are shown in Table 1.

[0015] Preferably, the axitinib-fumaric acid-acetic acid eutectic has the following crystallographic parameters: triclinic crystal system, chiral space group P-1; and the following unit cell parameters: α = 82.210(2)°, β = 75.602(2)°, γ = 86.744(2)°, cell volume

[0016] Preferably, the axitinib-fumaric acid-acetic acid eutectic exhibits two endothermic peaks in the differential scanning calorimetry (DSC) curve, namely 143.96℃ and 211.81℃.

[0017] The second aspect of this application provides a method for preparing axitinib-fumaric acid-acetic acid cocrystal, the specific preparation steps of which include: dissolving axitinib and fumaric 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-fumaric acid-acetic acid cocrystal.

[0018] Preferably, solvent A is a mixture of an organic solvent and acetic acid, wherein the organic solvent is one or two of methanol, ethanol, acetone, and isopropanol. Solvent A is further preferably a mixture of acetic acid-methanol, acetic acid-ethanol, acetic acid-acetone, or acetic acid-isopropanol.

[0019] Preferably, the volume ratio of the organic solvent to acetic acid in solvent A is 1 to 5:1.

[0020] Preferably, the molar ratio of axitinib to fumaric acid is 1:1.00 to 1.40; more preferably, the molar ratio of axitinib to fumaric acid is 1:1.00 to 1.2.

[0021] Preferably, the mass-to-volume ratio of axitinib to solvent A is 3 to 8:1, wherein the mass is expressed in mg and the volume in mL.

[0022] Preferably, the melting and heating temperature is 60–75°C.

[0023] Preferably, the cooling crystallization temperature is 10–30°C, and more preferably, the cooling crystallization temperature is 10–25°C.

[0024] Preferably, the crystallization time is 36 to 48 hours.

[0025] Preferably, the drying temperature is 60-65°C and the drying time is 5-9 hours.

[0026] Preferably, the solvent for washing the filter cake is selected from methanol, ethanol, acetone, and n-butanol.

[0027] A third aspect of the present invention provides a pharmaceutical composition comprising the axitinib-fumaric acid-acetic acid cocrystal prepared above, and mixed with other components.

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

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

[0030] More 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, hydroxypropylcellulose, hydroxypropyl methylcellulose, sodium carboxymethylcellulose, ethylcellulose, and povidone; the disintegrant is selected from one or more of sodium carboxymethyl starch, low-substituted hydroxypropylcellulose, croscarmellose sodium, and croscarmellose; and the lubricant is selected from one or more of magnesium stearate, micronized silica gel, talc, and sodium dodecyl sulfate.

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

[0032] The fourth aspect of this application provides the use of axitinib-fumaric acid-acetic acid cocrystal as an active ingredient in the preparation of a therapeutic anticancer drug.

[0033] Confirmation of crystal structure

[0034] The X-ray powder diffraction testing instrument and conditions for the axitinib-fumaric acid-acetic acid eutectic test described in this invention are as follows: PANalytical Empyrean X-ray powder diffractometer; light source: Cu target; flat sample stage; incident light path: BBHD; diffraction light path: PIXCEL; voltage: 45KV; current: 40mA; divergence slit: 1 / 4°; anti-scattering slit: 1°; Solar slit: 0.04rad; counting time per step: 0.5s; scanning range: 3–50°. Based on crystallographic data, the characteristic peaks in the corresponding X-ray powder diffraction pattern (Cu-Kα) are detailed in the appendix. Figure 1 And Table 1.

[0035] Table 1. Main PXRD peaks of axitinib-fumaric acid-acetic acid eutectic

[0036]

[0037]

[0038] X-ray crystal data were collected on a Rigaku XtaLAB Synergy instrument at a test temperature of 293(2) K using CuKa radiation. Data were collected in ω-scan mode and Lp correction was performed. The structure was resolved using the direct method, and all non-hydrogen atoms were identified using the difference Fourier method. Hydrogen atoms on all carbon and nitrogen atoms were obtained by theoretical hydrogenation. The structure was refined using the least squares method.

[0039] The crystallographic data of the axitinib-fumaric acid-acetic acid eutectic prepared by this invention were tested and analyzed. Its crystallographic parameters are: triclinic system, chiral space group P-1; cell parameters are: α = 82.210(2)°, β = 75.602(2)°, γ = 86.744(2)°, cell volume Molecular formula: C 28 H 26 N4O7S, molecular weight: 562.59. The packing diagram of the axitinib-fumaric acid-acetic acid eutectic of this invention is attached. Figure 2 As shown in the attached diagram. The ORTEP diagram of the axitinib-fumaric acid-acetic acid eutectic of the present invention shows that the crystal contains one molecule of axitinib, one molecule of fumaric acid, and one molecule of acetic acid, as indicated in the attached diagram. Figure 3 As shown.

[0040] Table 2. Major crystallographic data of the axitinib-fumaric acid-acetic acid eutectic.

[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-fumaric acid-acetic acid cocrystal 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 143.96℃ and 211.81℃, respectively. The TGA detection results indicate the presence of two weight loss steps. The first step indicates the crystal contains one molecule of acetic acid. Combined with the DSC / TGA results, the crystal form prepared in this invention is an axitinib-fumaric acid-acetic acid eutectic crystal.

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

[0046] The axitinib-fumaric acid-acetic acid cocrystal provided by this invention achieves significant improvements in stability, solubility, and permeability. After long-term photostability testing, the cocrystal exhibits good photostability. This axitinib-fumaric acid-acetic acid cocrystal has a regular crystal structure, uniform particle size, well-defined crystallographic parameters, and precise atomic spatial positions. Furthermore, the preparation method is simple, providing a material basis for improving the oral bioavailability of axitinib and making it suitable for industrial production and large-scale application. Attached Figure Description

[0047] Figure 1 X-ray powder diffraction pattern of axitinib-fumaric acid-acetic acid eutectic.

[0048] Figure 2 Packing diagram of axitinib-fumaric acid-acetic acid eutectic.

[0049] Figure 3 ORTEP diagram of axitinib-fumaric acid-acetic acid eutectic.

[0050] Figure 4 DSC-TGA image of axitinib-fumaric acid-acetic acid eutectic. 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] 482 mg axitinib and 172 mg fumaric acid were added to 20 mL acetic acid and 60 mL methanol. The mixture was heated to 65 °C and stirred to dissolve. The mixture was refluxed for 4 hours, then slowly cooled to 10–25 °C and allowed to stand for crystallization for 36 hours. The crystals were filtered, washed with methanol, and dried under vacuum at 60 °C for 6 hours to obtain axitinib-fumaric acid-acetic acid eutectic crystals with a yield of 98.01% and a purity of 99.75%.

[0055] Example 2

[0056] 404 mg axitinib and 132 mg fumaric acid were added to 20 mL acetic acid and 70 mL ethanol. The mixture was heated to 65 °C and stirred to dissolve. The mixture was refluxed for 4 hours, then slowly cooled to 10–25 °C and allowed to stand for crystallization for 36 hours. The mixture was filtered, the filter cake was washed with ethanol, and dried under vacuum at 60 °C for 6 hours to obtain axitinib-fumaric acid-acetic acid eutectic crystals with a yield of 98.51% and a purity of 99.71%.

[0057] Example 3

[0058] 397 mg axitinib and 125 mg fumaric acid were added to 15 mL acetic acid and 60 mL acetone, heated to 60 °C and stirred to dissolve. The mixture was refluxed for 4 hours, then slowly cooled to 10–25 °C and allowed to stand for crystallization for 36 hours. The mixture was filtered, the filter cake was washed with acetone, and dried under vacuum at 60 °C for 6 hours to obtain axitinib-fumaric acid-acetic acid eutectic crystals with a yield of 95.11% and a purity of 99.68%.

[0059] Example 4

[0060] 461 mg of axitinib and 185 mg of fumaric acid were added to 20 mL of acetic acid and 70 mL of n-butanol. The mixture was heated to 70 °C and stirred to dissolve. The mixture was refluxed for 4 hours, then slowly cooled to 10–25 °C and allowed to stand for crystallization for 36 hours. The crystals were filtered, washed with n-butanol, and dried under vacuum at 60 °C for 6 hours to obtain axitinib-fumaric acid-acetic acid eutectic crystals with a yield of 94.88% and a purity of 99.73%.

[0061] Verification Example:

[0062] This invention investigated the stability, hygroscopicity, solubility, and permeability of the prepared axitinib crystal form, as detailed below:

[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-fumaric acid-acetic acid eutectic 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 eutectic obtained in Example 1, the crystal form B of axitinib fumarate in CN202010787156.4 (obtained by repeating Example 1), and the crystal form of axitinib maleate 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-fumaric acid-acetic acid eutectic obtained by this invention has little or no hygroscopicity and is not easily deliquescent due to high humidity, facilitating long-term storage of the drug. Furthermore, PXRD analysis of the hygroscopic crystal forms showed that each crystal form remained stable.

[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-fumaric acid-acetic acid eutectic phase 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[Permeation cumulative amount (mg / cm 2 )]]> Example 1 0.5129 Axitinib fumarate crystal form B 0.1897

Claims

1. An axitinib eutectic, characterized in that, The molar ratio of axitinib, fumaric acid, and acetic acid in the crystal unit structure is 1:1:1; The eutectic, irradiated with Cu-Kα, exhibits characteristic peaks in its 2θ X-ray diffraction pattern at 7.08±0.2°, 14.65±0.2°, 16.23±0.2°, 18.25±0.2°, 20.97±0.2°, 23.06±0.2°, 24.97±0.2°, 25.80±0.2°, 27.04±0.2°, 29.04±0.2°, 29.67±0.2°, 38.21±0.2°, and 38.89±0.2°. The crystallographic parameters of the eutectic are: triclinic crystal system, chiral space group: P-1 The unit cell parameters are: a = 7.9893(2) Å, b = 13.1309(3) Å, c = 13.5127(3) Å, α = 82.210(2)°, β = 75.602(2)°, γ = 86.744(2)°, and the unit cell volume V = 1359.98(6) Å. 3 .

2. The axitinib eutectic 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 1.

3. The method for preparing axitinib eutectic according to any one of claims 1-2, characterized in that, The steps include: dissolving axitinib and fumaric 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 cocrystals; Solvent A is a mixture of an organic solvent and acetic acid, wherein the organic solvent is one or two of methanol, ethanol, acetone, and isopropanol; The cooling and crystallization temperature is 10–30°C.

4. The preparation method according to claim 3, characterized in that, The molar ratio of axitinib to fumaric acid is 1:1.00 to 1.

40.

5. The preparation method according to claim 3, characterized in that, The melting and heating temperature is 60–75°C; the cooling and crystallization temperature is 10–25°C.

6. The use of the axitinib cocrystal as described in any one of claims 1-2 as an active ingredient in the preparation of antitumor drugs.

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