Purification method of iremifungin, novel crystal form of iremifungin and preparation method of novel crystal form

Abstract

The invention discloses a purification method of iremifungin, a novel crystal form of the iremifungin and a preparation method of the novel crystal form. The purification method comprises the following step: preparing the crystal form APTI-I from the iremifungin. The crystal form APTI-I is radiated by Cu-K alpha, and an X-ray powder diffraction pattern expressed by a 2 theta angle has characteristic peaks at 9.2 degrees + / -0.2 degrees, 11.1 degrees + / -0.2 degrees and 13.7 degrees + / -0.2 degrees. The purification method of the iremifungin, provided by the invention, is good in stability, simple in preparation operation, good in purification effect and suitable for industrial large-scale production.

Description

Technical Field

[0001] The present invention relates to a purification method of ibrexafungerp, a new crystal form APTI-I of ibrexafungerp, and a preparation method of the new crystal form APTI-I. Background Art

[0002] Ibrexafungerp is a new oral antifungal drug developed by Scynexis, Inc. in the United States and was approved by the US Food and Drug Administration (FDA) in June 2021 for the treatment of vulvovaginal candidiasis (VVC) and as an antifungal agent to reduce the incidence of recurrent vulvovaginal candidiasis (RVVC). Ibrexafungerp exerts its antifungal effect by inhibiting 1,3-β-glucan synthase, thereby preventing the synthesis of the fungal cell wall and causing fungal death. The chemical structure of ibrexafungerp free base is as follows:

[0003]

[0004] The preparation method of ibrexafungerp free base can be referred to the prior art WO2010019203A1, such as scheme I therein. Currently, ibrexafungerp is mainly administered in the form of citrate, and its preparation method can be referred to Example 21 in the prior art US10174074B2 (specifically: dissolving equimolar amounts of ibrexafungerp and citric acid in 25 v of acetonitrile until clear, stirring at room temperature for 30 hours, and filtering after sufficient solid precipitates to obtain ibrexafungerp citrate). However, the inventors of the present application found that the ibrexafungerp free base prepared according to the above prior art contains impurities that are relatively difficult to remove: RRT = 0.86 impurity and RRT = 0.92 impurity ( Figure 1 the impurities corresponding to 10.85 min and 12.89 min in , and after preparing the free base containing these impurities into citrate, there is no purification effect, and finally the two impurities will form salts and continue into the target product, affecting the product quality. Therefore, it is necessary to complete the purification of the free base before preparing it into citrate to ensure the qualification of the subsequent product. Therefore, there is a need in the art for an efficient purification method for ibrexafungerp free base.

[0005] For many compound products, recrystallization and crystal purification is a low-cost and efficient purification method. During the microscopic molecular accumulation process of the same drug, polymorphism will be formed due to different accumulation methods. During the crystallization and purification process, different accumulation methods form different crystal forms, which also affect the purification and impurity removal effect, and then affect the quality of the product. For Arefungin, the only prior art that can be consulted is the methanol desolvate (MeOH desolvate) of Arefungin disclosed in US10174074B2, and according to the DSC and TGA data published by it, the crystal form still has weight loss and desolvation phenomena, and is actually a solvate or hydrate. However, the inventor of the present application failed to obtain MeOH desolvate after repeated repetitions according to the method disclosed in the prior art, but obtained an oily substance or a new crystal form APTI-A, and the final product did not achieve the ideal purification effect. Therefore, the preparation method of MeOH desolvate reported in the prior art is not stable and reliable, and the purification effect of repeated operations cannot meet the subsequent pharmaceutical requirements. Summary of the invention

[0006] In order to solve the shortcomings of the prior art method for preparing high-purity Arefungin, the present invention provides a method for purifying Arefungin, characterized in that the purification method comprises: preparing Arefungin into a crystalline form APTI-I,

[0007] The crystal form APTI-I, using Cu-Kα radiation, has an X-ray powder diffraction pattern represented by 2θ angles with characteristic peaks at 9.2°±0.2°, 11.1°±0.2° and 13.7°±0.2°.

[0008] In another preferred embodiment, the X-ray powder diffraction pattern of the crystalline form APTI-I also has characteristic peaks at one or more of the following 2θ angles:

[0009] 6.8°±0.2°、7.7°±0.2°、8.1°±0.2°、9.5°±0.2°、10.5°±0.2°、11.5°±0.2°、

[0010] 12.5°±0.2°、13.4°±0.2°、14.8°±0.2°、15.3°±0.2°、15.9°±0.2°、16.9°±0.2°、

[0011] There are characteristic peaks at 17.3°±0.2° and 18.7°±0.2°.

[0012] In another preferred embodiment, the differential scanning calorimetry spectrum of the crystalline form APTI-I has an exothermic peak at 263.8°C±5°C, and endothermic peaks at 334.7±5°C and 354.5±5°C.

[0013] In another preferred example, the crystalline form APTI-I is rod-shaped crystals with an aspect ratio of 5 to 7:1 and a particle size not exceeding 30 μm.

[0014] In another preferred example, the X-ray powder diffraction pattern of the crystalline form APTI-I is Figure 6 substantially identical.

[0015] In another preferred example, the differential scanning calorimetry pattern of the crystalline form APTI-I is Figure 7 substantially identical.

[0016] In another preferred example, the polarized light microscopy image of the crystalline form APTI-I is Figure 8 substantially identical.

[0017] In another preferred example, the purification method of the efinaconazole includes the following steps:

[0018] Dissolve efinaconazole in a crystallization solvent, heat to dissolve, slowly cool to the seeding temperature, add seeds of the crystalline form APTI-I, carry out seeding for 0.5 to 48 hours, slowly cool to the crystallization temperature, precipitate crystals, filter, and dry the obtained solid crystalline form APTI-I, or

[0019] Dissolve efinaconazole in a crystallization solvent, heat to dissolve, slowly cool to the seeding temperature, carry out seeding for 0.5 to 48 hours, slowly cool to the crystallization temperature, precipitate crystals, filter, and dry the obtained solid crystalline form APTI-I.

[0020] The crystallization solvent is selected from alcohol solvents.

[0021] In another preferred example, the alcohol solvents are selected from methanol, ethanol, n-propanol, isopropanol or a combination thereof, more preferably methanol and / or ethanol.

[0022] In another preferred example, in the purification method of the efinaconazole, the dosage of the organic solvent is such that the weight ratio of it to efinaconazole is 5 to 20 mL / 1 g, more preferably 5 to 10 mL / 1 g.

[0023] In another preferred example, in the purification method of the efinaconazole, the temperature for heating and dissolving is 50 to 100 °C, more preferably 50 to 70 °C.

[0024] In another preferred example, in the purification method of the efinaconazole, the seeding temperature is 30 to 45 °C, more preferably 35 to 40 °C.

[0025] In another preferred example, in the purification method of the efinaconazole, the seeding time is 1 to 8 hours, more preferably 1 to 3 hours.

[0026] In another preferred embodiment, in the purification method of efinaconazole, the crystallization temperature is 15 to 25 °C, more preferably 18 to 22 °C.

[0027] In another preferred embodiment, in the purification method of efinaconazole, the drying temperature is 45 to 55 °C, more preferably 48 to 52 °C.

[0028] In another preferred embodiment, in the purification method of efinaconazole, the time for cooling from the dissolution temperature to the seeding temperature is 20 to 90 min, more preferably 20 to 60 min.

[0029] In another preferred embodiment, in the purification method of efinaconazole, the time for cooling from the seeding temperature to the crystallization temperature is 30 to 180 min, more preferably 50 to 90 min.

[0030] In another preferred embodiment, the purification method of efinaconazole further includes dissolving efinaconazole in a good solvent before dissolving it in a crystallization solvent, and then concentrating to dryness to obtain amorphous efinaconazole. The good solvent is selected from ester solvents, ketone solvents or combinations thereof, or a combination of the ester solvent and / or the ketone solvent and the crystallization solvent.

[0031] In another preferred embodiment, the ester solvent is selected from ethyl acetate, isopropyl acetate, methyl acetate, ethyl formate, methyl formate or combinations thereof, more preferably ethyl acetate.

[0032] In another preferred embodiment, the ketone solvent is selected from acetone, 2-butanone, methyl isobutyl ketone, or combinations thereof.

[0033] The present invention also provides a crystalline form APTI-I of efinaconazole. Using Cu-Kα radiation, its X-ray powder diffraction pattern shows characteristic peaks at 9.2° ± 0.2°, 11.1° ± 0.2° and 13.7° ± 0.2° in terms of 2θ angle.

[0034] In another preferred embodiment, the X-ray powder diffraction pattern of the crystalline form APTI-I of efinaconazole also has characteristic peaks at one or more of the following 2θ angles:

[0035] 6.8° ± 0.2°, 7.7° ± 0.2°, 8.1° ± 0.2°, 9.5° ± 0.2°, 10.5° ± 0.2°, 11.5° ± 0.2°,

[0036] 12.5° ± 0.2°, 13.4° ± 0.2°, 14.8° ± 0.2°, 15.3° ± 0.2°, 15.9° ± 0.2°, 16.9° ± 0.2°,

[0037] 17.3° ± 0.2°, 18.7° ± 0.2° have characteristic peaks.

[0038] In another preferred example, the differential scanning calorimetry (DSC) thermogram of crystalline form APTI-I has an exothermic peak at 263.8 °C ± 5 °C, and endothermic peaks at 334.7 ± 5 °C and 354.5 ± 5 °C.

[0039] In another preferred example, crystalline form APTI-I is in the form of rod-shaped crystals with an aspect ratio of 5 - 7:1 and a particle size not exceeding 30 μm.

[0040] In another preferred example, the X-ray powder diffraction pattern of crystalline form APTI-I is Figure 6 substantially identical.

[0041] In another preferred example, the differential scanning calorimetry (DSC) thermogram of crystalline form APTI-I is Figure 7 substantially identical.

[0042] In another preferred example, the polarized light microscopy image of crystalline form APTI-I is Figure 8 substantially identical.

[0043] The present invention also provides a method for preparing crystalline form APTI-I, comprising the steps of:

[0044] Dissolve efinaconazole in a crystallization solvent, heat to dissolve, then slowly cool to the seeding temperature, add seeds of crystalline form APTI-I, conduct seeding for 0.5 - 48 hours, slowly cool to the crystallization temperature to precipitate crystals, filter, and dry the obtained solid crystalline form APTI-I, or

[0045] Dissolve efinaconazole in a crystallization solvent, heat to dissolve, then slowly cool to the seeding temperature, conduct seeding for 0.5 - 48 hours, slowly cool to the crystallization temperature to precipitate crystals, filter, and dry the obtained solid crystalline form APTI-I.

[0046] The crystallization solvent is selected from alcohol solvents.

[0047] In another preferred example, the alcohol solvents are selected from methanol, ethanol, n-propanol, isopropanol or combinations thereof, more preferably methanol and / or ethanol.

[0048] In another preferred example, in the method for preparing crystalline form APTI-I, the dosage of the organic solvent is such that the weight ratio of the organic solvent to efinaconazole is 5 - 20 mL / 1 g, more preferably 5 - 10 mL / 1 g.

[0049] In another preferred example, in the method for preparing crystalline form APTI-I, the organic solvent is selected from methanol, ethanol, n-propanol, isopropanol, acetone, 2-butanone or combinations thereof, more preferably methanol and / or ethanol.

[0050] In another preferred example, in the preparation method of crystalline form APTI-I, the temperature for heating and dissolving is 50 to 100 °C, more preferably 50 to 70 °C.

[0051] In another preferred example, in the preparation method of crystalline form APTI-I, the seeding temperature is 30 to 45 °C, more preferably 35 to 40 °C.

[0052] In another preferred example, in the preparation method of crystalline form APTI-I, the seeding time is 1 to 8 hours, more preferably 1 to 3 hours.

[0053] In another preferred example, in the preparation method of crystalline form APTI-I, the crystallization temperature is 15 to 25 °C, more preferably 18 to 22 °C.

[0054] In another preferred example, in the preparation method of crystalline form APTI-I, the drying temperature is 45 to 55 °C, more preferably 48 to 52 °C.

[0055] In another preferred example, in the preparation method of crystalline form APTI-I, the time for cooling from the dissolution temperature to the seeding temperature is 20 to 90 min, more preferably 20 to 60 min.

[0056] In another preferred example, in the preparation method of crystalline form APTI-I, the time for cooling from the seeding temperature to the crystallization temperature is 30 to 180 min, more preferably 50 to 90 min.

[0057] In another preferred example, the preparation method of crystalline form APTI-I of eravacycline further comprises dissolving eravacycline in a good solvent before dissolving it in a crystallization solvent, and then concentrating to dryness to obtain amorphous eravacycline. The good solvent is selected from ester solvents, ketone solvents or a combination thereof, or a combination of the ester solvent and / or the ketone solvent and the crystallization solvent.

[0058] In another preferred example, the ester solvent is selected from ethyl acetate, isopropyl acetate, methyl acetate, ethyl formate, methyl formate or a combination thereof, more preferably ethyl acetate.

[0059] In another preferred example, the ketone solvent is selected from acetone, 2-butanone, methyl isobutyl ketone, or a combination thereof, more preferably acetone.

[0060] The present invention also provides the use of the above-mentioned crystalline form APTI-I of eravacycline in the preparation of a drug containing eravacycline or in the purification of eravacycline or its salt.

[0061] The present invention also provides an efinaconazole crystal form APTI-A, which, using Cu-Kα radiation, has characteristic peaks in its X-ray powder diffraction pattern at 2θ angles of 13.0° ± 0.2°, 13.4° ± 0.2° and 16.0° ± 0.2°.

[0062] In another preferred embodiment, the X-ray powder diffraction pattern of the efinaconazole crystal form APTI-A further has characteristic peaks at one or more of the following 2θ angles:

[0063] 5.3° ± 0.2°, 6.3° ± 0.2°, 10.4° ± 0.2°, 10.8° ± 0.2°, 14.6° ± 0.2°, 15.6° ± 0.2°, 17.4° ± 0.2°, 17.9° ± 0.2°, 20.3° ± 0.2°, 21.1° ± 0.2°. Description of the Drawings

[0064] Figure 1 is the HPLC chromatogram of the amorphous crude efinaconazole free base;

[0065] Figure 2 is the XRPD pattern of the efinaconazole crystal form APTI-A obtained in Comparative Example 1;

[0066] Figure 3 is the HPLC chromatogram of the efinaconazole free base oil obtained in Comparative Example 2;

[0067] Figure 4 is the HPLC chromatogram of the efinaconazole citrate obtained in Comparative Example 3

[0068] Figure 5 is the HPLC chromatogram of the efinaconazole crystal form APTI-I prepared in Example 1;

[0069] Figure 6 is the XRPD pattern of the efinaconazole crystal form APTI-I prepared in Example 1;

[0070] Figure 7 is the DSC pattern of the efinaconazole crystal form APTI-I prepared in Example 1;

[0071] Figure 8 is the PLM image of the efinaconazole crystal form APTI-I prepared in Example 1;

[0072] Figure 9 is the XRPD pattern of the efinaconazole crystal form APTI-I prepared in Example 2;

[0073] Figure 10 is the HPLC chromatogram of the efinaconazole crystal form APTI-I prepared in Example 2;

[0074] Figure 11 XRPD overlay plots before and after grinding of efinaconazole polymorph APTI-I;

[0075] Figure 12 XRPD overlay plots before and after moisture absorption of efinaconazole polymorph APTI-I;

[0076] Figure 13 XRPD overlay plot obtained from the moisture stability test of efinaconazole polymorph APTI-I;

[0077] Figure 14 HPLC chromatogram of citrate in Example 7. Detailed Description of the Invention

[0078] During the preparation of efinaconazole free base according to the route scheme I disclosed in the prior art WO2010019203A1, the inventors of the present application found that there were impurities with retention times of RRT 0.86 and RRT 0.92 ( Figure 1 corresponding retention times in

[0079]

[0080] being 10.85 min and 12.89 min, respectively) in the product, and their structural formulas are as follows: Moreover, the applicant found that after preparing the free base into citrate, there was no purification effect, and finally the two impurities would form salts and carry over into the target product, affecting the product quality. Therefore, it is necessary to complete the purification of the free base before preparing it into citrate in order to provide a high-quality pharmaceutical citrate. The inventors of the present application attempted to prepare MeOH desolvate according to the method disclosed in Example 2 of the prior art US10174074B2 to obtain a raw material with higher purity, but found it difficult to prepare the claimed product, and finally obtained an oily substance adhering to the container wall or a new polymorph APTI-A (its XRPD pattern is shown in Figure 2 ). Moreover, neither the oily substance nor polymorph APTI-A had an obvious purification effect.

[0081] Scheme I

[0082]

[0083] P = protecting group

[0084] P 0 = hydrogen or protecting group

[0085] In view of the problem that the free base of eravacycline is difficult to purify in the prior art, the inventors of the present application have conducted in-depth research and surprisingly found that preparing the free base of eravacycline into crystalline form APTI-I can significantly improve the purity of eravacycline. The purity of this crystalline form can reach more than 99.9%, with no impurities greater than 0.1%. Moreover, the preparation method of this crystalline form APTI-I is simple, stable, and has a high yield. On this basis, the present invention has been completed.

[0086] Efinaconazole Polymorph APTI-I

[0087] The crystalline form APTI-I of eravacycline provided by the present invention is a new crystalline form of the free base of eravacycline. Using Cu-Kα radiation, its X-ray powder diffraction pattern expressed in 2θ angles is at 9.2° ± 0.2°, 11.1° ± 0.2°, and 13.7° ± 0.2°.

[0088] Furthermore, the X-ray powder diffraction pattern of the crystalline form APTI-I of eravacycline provided by the present invention also has characteristic peaks at one or more of the following 2θ angles:

[0089] 6.8° ± 0.2°, 7.7° ± 0.2°, 8.1° ± 0.2°, 9.5° ± 0.2°, 10.5° ± 0.2°, 11.5° ± 0.2°, 12.5° ± 0.2°, 13.4° ± 0.2°, 14.8° ± 0.2°, 15.3° ± 0.2°, 15.9° ± 0.2°, 16.9° ± 0.2°, 17.3° ± 0.2°, 18.7° ± 0.2°.

[0090] Furthermore, the XRPD data of the crystalline form APTI-I of eravacycline provided by the present invention are basically as shown in Table 1;

[0091] Table 1

[0092] No. 2θ (°) Relative Intensity 1 6.8 18.4％ 2 7.7 7.6％ 3 8.1 13.4％ 4 9.2 42.9％ 5 9.5 8.6％ 6 10.5 29.8％ 7 11.1 100.0％ 8 11.5 6.3％ 9 12.5 12.0％ 10 13.4 3.5％ 11 13.7 39.7％ 12 14.8 24.5％ 13 15.3 10.1％ 14 15.9 4.9％ 15 16.9 6.0％ 16 17.3 7.4％ 17 18.7 5.0％

[0093] Furthermore, the XRPD pattern of the crystalline form APTI-I of eravacycline provided by the present invention is Figure 6 substantially identical.

[0094] Furthermore, the differential scanning calorimetry pattern of the crystalline form APTI-I of eravacycline provided by the present invention is Figure 7 substantially identical.

[0095] Furthermore, the polarized light microscope (PLM) image of the crystalline form APTI-I of eravacycline provided by the present invention is Figure 8 substantially identical.

[0096] Purification Method of Efinaconazole

[0097] The purification method of efinaconazole provided by the present invention is to prepare it into crystal form APTI-I. The purity of the crystal form APTI-I product is not less than 99.9%, and there are no impurities greater than 0.1%. During the purification process, it is preferred to add crystal seeds, which can induce crystallization and ensure the stability of the purification process.

[0098] In some specific embodiments of the present invention, the purification method of efinaconazole includes the steps of: dissolving efinaconazole in a crystallization solvent, heating to dissolve, slowly cooling to the crystal cultivation temperature, adding crystal form APTI-I as crystal seeds, after crystal cultivation for a period of time, slowly cooling to the crystallization temperature, precipitating crystals, filtering, and drying the obtained solid crystal form APTI-I. In some specific embodiments of the present invention, the purification method of efinaconazole includes the steps of: dissolving efinaconazole in a crystallization solvent, heating to dissolve, slowly cooling to the crystal cultivation temperature, after crystal cultivation for a period of time, slowly cooling to the crystallization temperature, precipitating crystals, filtering, and drying the obtained solid crystal form APTI-I.

[0099] The crystallization solvent includes but is not limited to alcohol solvents such as methanol, ethanol, n-propanol, and isopropanol.

[0100] There is no specific limitation on the crystal cultivation time. Preferably, it is 0.5 to 48 hours, more preferably 1 to 8 hours.

[0101] In some specific embodiments of the present invention, before dissolving efinaconazole in a crystallization solvent for crystallization, efinaconazole is dissolved in a good solvent and then concentrated to dryness to obtain amorphous efinaconazole (usually in a foamy state), and this amorphous form is more easily soluble in the crystallization solvent.

[0102] The good solvent preferably includes but is not limited to ester solvents such as ethyl acetate, isopropyl acetate, methyl acetate, ethyl formate, and methyl formate, as well as ketone solvents such as acetone, 2-butanone, and methyl isobutyl ketone, or a combination of ester solvents and ketone solvents, or a combination of ester solvents and / or ketone solvents and the above crystallization solvents.

[0103] Preparation Method of Efinaconazole Polymorph APTI-I

[0104] The preparation method of efinaconazole crystal form APTI-I is the same as the above purification method of efinaconazole

[0105] Efinaconazole Polymorph APTI-A

[0106] The present invention also provides efinaconazole crystal form APTI-A, and its X-ray powder data is shown in Table 2;

[0107] Table 2

[0108]

[0109]

[0110] Efinaconazole Polymorph APTI-A is a new polymorph obtained during the preparation of the MeOH desolvate in Example 2 of the repeated original US10927142.

[0111] By preparing the crude efinaconazole free base into Polymorph APTI-I, the present invention can obtain a high-purity efinaconazole free base raw material with a purity of 99.9% or higher, no impurities greater than 0.1%, and the preparation method is simple, with good repeatability and high yield.

[0112] The following specific examples are used to further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions in the following examples are usually carried out under conventional conditions. Unless otherwise specified, percentages and parts are by weight. The raw materials used are generally commercially available without special instructions, or can be prepared according to the methods disclosed in the prior art.

[0113] In the description of the present invention, "room temperature" refers to 0 - 40°C. For example, 5 - 35°C, 15 - 28°C, 20 - 25°C, 28°C, etc. all belong to room temperature.

[0114] The preparation method of the crude efinaconazole free base in the following comparative examples and examples refers to Route Scheme I of Patent WO2010019203A1.

[0115] General Method

[0116] 1. XRPD Pattern Determination Method

[0117] X-ray powder diffractometer: BRUKER AXSD2 PHASER X-ray powder diffractometer; radiation source: Intensity ratio α1 / α2 is 0.5; Generator kv: 30.0 kv; Generator mA: 10.0 mA; scanning range: 3.0 - 40.0°.

[0118] 2. DSC Determination Method

[0119] METTLEER DSC1 differential scanning calorimeter heating program: heating at 20°C per minute from 30°C to 380°C.

[0120] Comparative Example 1 attempts to prepare the methanol desolvate (MeOH desolvate) disclosed in the prior art US10174074B2

[0121] Weigh 5 g of amorphous crude efruxetine free base with HPLC purity of 99.27% (HPLC chromatogram is shown in Figure 1 ). Add 45 mL of methanol, heat to 60 °C until dissolved clearly, then slowly cool to 40 °C in 30 min. After stirring for 2 h, the solution is slightly turbid. Slowly add 10 mL of water dropwise, and a large amount of solid precipitates. Cool to 20 °C, filter the precipitated product, wash it with 5 mL of methanol / water 4 / 1 mixed solvent, and then transfer it to a vacuum dryer at 50 °C for 4 h to obtain 3.4 g of solid. The XRPD is detected as crystal form APTI-A ( Figure 2 ), and the HPLC purity is 99.32%. The methanol desolvate disclosed in the prior art US10174074B2 is not obtained.

[0122] Comparative Example 2 attempts to prepare the MeOH desolvate of the prior art US10174074B2

[0123] Weigh 5 g of amorphous crude efruxetine free base with HPLC purity of 99.27% (its HPLC chromatogram is shown in Figure 1 ). Add 50 mL of 2-methyltetrahydrofuran and dissolve clearly at room temperature. Concentrate to 20 mL at 50 °C, then add 40 mL of methanol and stir at 40 °C for 2 h. There is no solid precipitation and the solution is clear. After concentrating the solution to 45 mL at 40 °C, slowly add 10 mL of water dropwise. During the dropping process, a white milky substance is observed to precipitate and then quickly settle and stick to the wall to form an oily substance. Cool to 20 °C, and the obtained product is an oily substance. The methanol desolvate disclosed in the prior art US10174074B2 is not obtained. Sampling and detecting the purity by HPLC, it is found that the purity of this oily substance has no obvious improvement compared with the amorphous crude free base (its HPLC chromatogram is shown in Figure 3 ).

[0124] Comparative Example 3 prepares efruxetine citrate

[0125] Weigh 450 mg of amorphous crude efruxetine free base with HPLC purity of 99.27% (HPLC chromatogram is shown in Figure 1 ). After adding 1.1 eq (120 mg) of citric acid aqueous solution, add 5 mL of ACN and 0.2 mL of water dropwise. The mixture becomes viscous. Heat to 50 °C and stir to obtain a clear solution. After keeping warm for 2 h, slowly cool to 30 °C, and the solution becomes turbid and solid precipitates. With a temperature rise and fall rate of 10 °C / hour, heat to 50 °C and then cool to 20 °C, and cycle 2 times. After keeping warm and stirring at 20 °C for 16 h, filter. The obtained solid is detected by HPLC, and its HPLC purity is 99.39%. Its HPLC chromatogram is shown in Figure 4 . It shows that salification has no obvious effect on removing impurities and cannot meet the requirement that the single impurity for medicinal use is lower than 0.10%.

[0126] Example 1 prepares efruxetine crystal form APTI-I

[0127] Weigh 5 g of amorphous crude efruxetine free base with an HPLC purity of 99.27%, add 25 mL of methanol, heat up to 60 °C to obtain a clear solution. Cool the solution to 40 °C in 30 min, keep it at this temperature and stir for 1 h, then a little turbidity appears. Continue to slowly cool it to 20 °C in 1 h, precipitate solids, filter. The obtained solids are rinsed with 5 mL of methanol, then transferred to a vacuum dryer at 50 °C for 4 h to obtain 3.2 g of solids. Using HPLC detection, its purity is 99.77% (its HPLC chromatogram is shown in Figure 5 , and there are no impurities greater than 0.1%). Using XRPD detection, this solid is a crystal, named crystal form APTI-I (its XRPD chromatogram is shown in Figure 6 ). Using DSC to detect this crystal form APTI-I, the results are shown in Figure 7 , and its PLM diagram is shown in Figure 8 .

[0128] Example 2 Preparation of Efruxetine Crystal Form APTI-I

[0129] Weigh 50 g of amorphous crude efruxetine free base with an HPLC purity of 99.27%, add 250 mL of ethanol and 250 mL of ethyl acetate. After the solid is completely dissolved, filter. The filtrate is concentrated to dryness under reduced pressure at 50 °C to obtain a foamy amorphous solid. Add 250 mL of methanol to it. After dissolving clearly at 50 °C, continue to concentrate to dryness. After the residue is cooled to room temperature, add 250 mL of methanol to it, which does not dissolve. Heat up to 50 - 60 °C, and the residue is completely dissolved. Cool the solution to 40 °C in 30 minutes, no solids precipitate. Add 0.5 g of crystal form APTI-I prepared in Example 2 as crystal seeds, the solution begins to become turbid. Continue to keep it at this temperature and grow crystals for 1 h, then cool it to 20 °C, a large amount of solids precipitate. Filter. The obtained solids are rinsed with 50 mL of methanol, then transferred to a vacuum dryer at 50 °C for 16 h to obtain 46.8 g of solids. Using XRPD detection, this solid is crystal form APTI-I (its XRPD chromatogram is shown in Figure 9 ), its HPLC purity is 99.94% ( Figure 10 ), and the yield is 93.6%.

[0130] The comparison summary of the impurity removal effects of the efruxetine free base starting material and the above crystal forms APTI-A and APTI-I is shown in Table 3. The results show that the impurity removal effect of crystal form APTI-I on several key impurities affecting product quality is significantly better than that of crystal form APTI-A in the comparative example.

[0131] Table 3

[0132]

[0133]

[0134] Note: In Table 3, the “-” in the impurity removal rate indicates that the impurities have not decreased, but increased (enriched). For example, “-300%” means that the impurities in the product after impurity removal are 3 times higher than those in the raw material; “-20%” means that the impurities in the product after impurity removal are 0.2 times higher than those in the original material. The impurity removal rate “25%” means that the impurities in the original product after impurity removal are 25% lower than those in the raw material.

[0135] Example 3-a to 3-e Preparation of Arifungin Crystalline Form APTI-I

[0136] From the comparison between Example 1 and Example 2, it is found that the solution of adding seed crystals is better. Example 2 is repeated to stably obtain the crystal form APTI-I. The results are shown in Table 4.

[0137] Table 4

[0138]

[0139] Based on the above, it can be seen that the purity and yield of the crystal form APTI-I prepared in Example 2 and Examples 3a-3e are both high. The method for preparing the crystal form APTI-I of Arefungin is suitable as a method for purifying the crude amorphous free base of Arefungin.

[0140] Example 4 Testing the grinding stability of the crystalline form of Arefungin APTI-I

[0141] 200 mg of the crystalline form APTI-I of Example 2 (HPLC purity 99.94%) was weighed and manually dry-ground in an agate mortar for 30 min and then XRPD was detected. The results are shown in Figure 11 (From bottom to top, they are the XRPD spectra of the crystal form APTI-I before and after grinding). Figure 11 It can be seen that the crystal form of APTI-I did not change before and after grinding, and the HPLC purity did not change significantly (see Table 5).

[0142] Example 5: Testing the Hygroscopic Stability of Arefungin Crystalline Form APTI-I

[0143] 1.0 g of Example 2 Arefungin crystal form APTI-I (HPLC purity 99.94%) was weighed and placed in a 80% RH desiccator for 24 h before XRPD detection. The results are shown in Figure 12 (From bottom to top, they are the XRPD spectra of crystalline APTI-I before and after being placed in a 80% RH desiccator for 24 hours.) Figure 12 It can be seen that the crystal form of APTI-I did not change before and after storage, and the HPLC purity did not change significantly (see Table 5). The sample gained 1.6% in weight and was slightly hygroscopic.

[0144] Example 6: Testing the temperature and humidity stability of the crystalline form APTI-I of eravacycline

[0145] The crystalline form APTI-I of eravacycline was packaged in PE bags and aluminum foil bags and placed at 25°C / 60% RH and 40°C / 75% RH for 1 week respectively. There were no obvious changes in the crystalline form and purity. The superimposed stability diagrams are shown in Figure 13 (wherein, from bottom to top, are the starting material crystalline form APTI-I and its XRPD patterns after being placed at 25°C / 60% RH and 40°C / 75% RH for 1 week). It can be seen from Figure 13 that the crystalline form of the crystalline form APTI-I did not change before and after placement. The purity detected by HPLC also did not change significantly (see Table 5).

[0146] The stability experiment data of Examples 4-6 above are summarized in Table 5.

[0147] Table 5

[0148] Stability Conditions Time Polymorph Purity Starting Material <![CDATA[T0]]> Polymorph APTI-I 99.94％ Grinding 30 Minutes Polymorph APTI-I 99.95％ Moisture Absorption 24 Hours Polymorph APTI-I 99.92％ 25 °C / 60% RH 7 Days Polymorph APTI-I 99.93％ 40 °C / 75% RH 7 Days Polymorph APTI-I 99.94％

[0149] Example 7 Preparation of eravacycline citrate from the crystalline form APTI-I of eravacycline

[0150] Weigh 4.5 g of the eravacycline crystalline form APTI-I sample with an HPLC purity of 99.94% (Example 2). After adding 1.1 eq (1.2 g) of citric acid, 50 mL of ACN and 2 mL of water were added dropwise. The temperature was raised to 50°C and stirred until clear. After holding for 2 h, the temperature was slowly lowered (naturally cooled) to 30°C. The solution became turbid and solids precipitated. At a temperature rise and fall rate of 10°C / hour, the temperature was raised to 50°C and then lowered to 20°C. After 2 cycles, the product was held and stirred at 20°C for 16 h, and then filtered and detected by HPLC( Figure 14 ) to be 99.96%. The product purity meets the pharmaceutical requirements.

[0151] In summary, the crystalline form APTI-I of eravacycline obtained during the purification of the crude eravacycline free base in the present invention is a new crystalline form different from the existing publicly disclosed crystalline forms. The product preparation is simple, has good reproducibility, obvious impurity removal effect, and the product quality meets the drug regulations, making it suitable for industrial scale-up production.

Claims

1. A method for purifying arefungin, characterized in that: The purification method includes preparing efinaconazole into crystalline form APTI-I. For the crystalline form APTI-I, using Cu-Kα radiation, its X-ray powder diffraction pattern expressed in 2θ angle has characteristic peaks at 9.2°±0.2°, 11.1°±0.2° and 13.7°±0.2°.

2. The method for purifying alefungin according to claim 1, characterized in that: The crystalline form APTI-I also has one or more characteristics selected from the following: (i) Its X-ray powder diffraction pattern also has characteristic peaks at one or more of the following 2θ angles: 6.8°±0.2°, 7.7°±0.2°, 8.1°±0.2°, 9.5°±0.2°, 10.5°±0.2°, 11.5°±0.2°, 12.5°±0.2°, 13.4°±0.2°, 14.8°±0.2°, 15.3°±0.2°, 15.9°±0.2°, 16.9°±0.2°, 17.3°±0.2°, 18.7°±0.2°; (ii) Its differential scanning calorimetry pattern has an exothermic peak at 263.8℃±5℃ and endothermic peaks at 334.7±5℃ and 354.5±5℃; (iii) It is in the form of rod-shaped crystals with an aspect ratio of 5-7:1 and a particle size not exceeding 30μm; (iv) Its X-ray powder diffraction pattern is substantially consistent with Figure 6; (v) Its differential scanning calorimetry pattern is substantially consistent with Figure 7; (vi) Its polarized light microscopy image is substantially consistent with Figure 8.

3. The purification method of efinaconazole according to claim 1, characterized in that, The purification method includes the following steps: Dissolve efinaconazole in a crystallization solvent. After heating and dissolving, slowly cool down to the seeding temperature, add seeds of crystalline form APTI-I, conduct seeding for 0.5-48 hours, slowly cool down to the crystal precipitation temperature, precipitate crystals, filter, and dry the obtained solid crystalline form APTI-I, or Dissolve efinaconazole in a crystallization solvent. After heating and dissolving, slowly cool down to the seeding temperature, conduct seeding for 0.5-48 hours, slowly cool down to the crystal precipitation temperature, precipitate crystals, filter, and dry the obtained solid crystalline form APTI-I. The crystallization solvent is selected from alcohol solvents. Preferably, the alcohol solvents are selected from methanol, ethanol, n-propanol, isopropanol or a combination thereof. More preferably, methanol and / or ethanol.

4. According to the purification method of efinaconazole described in claim 3, characterized in that The dosage of the organic solvent is such that the weight ratio of it to efinaconazole is 5-20 mL / 1 g. More preferably, 5-10 mL / 1 g, and / or The temperature for heating and dissolving is 50-100℃. More preferably 50-70℃, and / or The seeding temperature is 30-45℃. More preferably 35-40℃, and / or The seeding time is 1-8 hours. More preferably 1-3 hours, and / or The crystal precipitation temperature is 15-25℃. More preferably 18-22℃, and / or The drying temperature is 45-55℃. More preferably 48-52℃. The time for cooling from the dissolution temperature to the seeding temperature is 20-90 min. More preferably 20-60 min, and / or The time for cooling from the seeding temperature to the crystal precipitation temperature is 30-180 min. More preferably 50-90 min.

5. The purification method of efinaconazole according to claim 3, wherein The purification method further includes dissolving efinaconazole in a good solvent before dissolving it in a crystallization solvent, and then concentrating the solution to dryness to obtain amorphous efinaconazole. The good solvent is selected from ester solvents, ketone solvents or combinations thereof, or a combination of the ester solvent and / or the ketone solvent and the crystallization solvent. Preferably, the ester solvent is selected from ethyl acetate, isopropyl acetate, methyl acetate, ethyl formate, methyl formate, or combinations thereof. More preferably, it is ethyl acetate. Preferably, the ketone solvent is selected from acetone, 2-butanone, methyl isobutyl ketone, or combinations thereof. More preferably, it is acetone.

6. An efinaconazole polymorph APTI-I, characterized in that, Using Cu-Kα radiation, its X-ray powder diffraction pattern in terms of 2θ angles is at 9.2° ± 0.2°, 11.1° ± 0.2°, and 13.7° ± 0.2°.

7. The crystalline form APTI-I according to claim 6, wherein The efinaconazole crystal form APTI-I further has one or more of the following characteristics: (i) Its X-ray powder diffraction pattern further has characteristic peaks at one or more of the following 2θ angles: There are characteristic peaks at 6.8° ± 0.2°, 7.7° ± 0.2°, 8.1° ± 0.2°, 9.5° ± 0.2°, 10.5° ± 0.2°, 11.5° ± 0.2°, 12.5° ± 0.2°, 13.4° ± 0.2°, 14.8° ± 0.2°, 15.3° ± 0.2°, 15.9° ± 0.2°, 16.9° ± 0.2°, 17.3° ± 0.2°, 18.7° ± 0.2°. (ii) Its differential scanning calorimetry pattern has an exothermic peak at 263.8°C ± 5°C and endothermic peaks at 334.7 ± 5°C and 354.5 ± 5°C. (iii) It is in the form of rod-shaped crystals with an aspect ratio of 5 - 7:1 and a particle size not exceeding 30 μm. (iv) Its X-ray powder diffraction pattern is substantially the same as that in Figure 6. (v) Its differential scanning calorimetry pattern is substantially the same as that in Figure 7. (vi) Its polarized light microscopy image is substantially the same as that in Figure 8.

8. The preparation method of crystalline form APTI-I according to any one of claims 6-7, characterized in that, The preparation method includes the steps of: Dissolving efinaconazole in a crystallization solvent, heating to dissolve, slowly cooling to the seeding temperature, adding crystal form APTI-I seeds, seeding for 0.5 - 48 hours, slowly cooling to the crystallization temperature, precipitating crystals, filtering, and drying the obtained solid crystal form APTI-I, or Dissolving efinaconazole in a crystallization solvent, heating to dissolve, slowly cooling to the seeding temperature, seeding for 0.5 - 48 hours, slowly cooling to the crystallization temperature, precipitating crystals, filtering, and drying the obtained solid crystal form APTI-I. The crystallization solvent is selected from alcohol solvents. Preferably, the alcohol solvent is selected from methanol, ethanol, n-propanol, isopropanol, or combinations thereof. More preferably, it is methanol and / or ethanol.

9. The preparation method of crystalline form APTI-I according to claim 8, characterized in that, The dosage of the organic solvent is such that the weight ratio of it to efinaconazole is 5 - 20 mL / 1 g. More preferably, it is 5 - 10 mL / 1 g, and / or The organic solvent is selected from methanol, ethanol, n-propanol, isopropanol, acetone, 2-butanone, or combinations thereof. More preferably, it is methanol and / or ethanol, and / or The temperature for heating and dissolving is 50 - 100°C. More preferably, it is 50 - 70°C, and / or The crystallization temperature is 30 to 45 °C, more preferably 35 to 40 °C, and / or the crystallization time is 1 to 8 hours, more preferably 1 to 3 hours, and / or the crystallization temperature is 15 to 25 °C, more preferably 18 to 22 °C, and / or the drying temperature is 45 to 55 °C, more preferably 48 to 52 °C, the time for cooling from the dissolution temperature to the crystallization temperature is 20 to 90 min, more preferably 20 to 60 min, and / or the time for cooling from the crystallization temperature to the crystallization temperature is 30 to 180 min, more preferably 50 to 90 min.

10. The preparation method of crystalline form APTI-I according to claim 8, characterized in that, The purification method further includes dissolving efinaconazole in a good solvent, and then concentrating to dryness to obtain amorphous efinaconazole before dissolving efinaconazole in the crystallization solvent, the good solvent is selected from ester solvents, ketone solvents or combinations thereof, or a combination of the ester solvent and / or the ketone solvent and the crystallization solvent, preferably, the ester solvent is selected from ethyl acetate, isopropyl acetate, methyl acetate, ethyl formate, methyl formate, etc., more preferably, ethyl acetate, preferably, the ketone solvent is selected from acetone, 2-butanone, methyl isobutyl ketone, or a combination thereof, more preferably, acetone.

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