阅读说明：本技术 一种依帕司他新晶型及其制备方法和应用 (Novel crystal form of epalrestat, preparation method and application thereof ) 是由 颜世强 郭伟 曹焕英 杨杰 何淑旺 程中伟 胡醒 于 2021-08-19 设计创作，主要内容包括：本发明属于医药技术领域,提供了一种依帕司他新晶型及其制备方法和应用。本发明依帕司他新晶型的X-射线粉末衍射图在衍射角2θ为6.39±0.2°,7.57±0.2°,12.69±0.2°,14.67±0.2°,15.04±0.2°,21.79±0.2°,24.36±0.2°,25.59±0.2°,27.30±0.2°和31.48±0.2°处有特征衍射峰。该依帕司他新晶型具有优异的溶出性能和水溶性,提高了其生物利用度；而且,该依帕司他新晶型具有优异的流动性,休止角可达26°以下,压缩系数均小于10％,Hausner比在1.00～1.11之间,适宜作为原料药用于其前体药物或药物制剂的生产。(The invention belongs to the technical field of medicines, and provides a novel crystal form of epalrestat, and a preparation method and application thereof. The X-ray powder diffraction pattern of the novel crystal form of epalrestat has characteristic diffraction peaks at diffraction angles 2 theta of 6.39 +/-0.2 degrees, 7.57 +/-0.2 degrees, 12.69 +/-0.2 degrees, 14.67 +/-0.2 degrees, 15.04 +/-0.2 degrees, 21.79 +/-0.2 degrees, 24.36 +/-0.2 degrees, 25.59 +/-0.2 degrees, 27.30 +/-0.2 degrees and 31.48 +/-0.2 degrees. The novel crystal form of epalrestat has excellent dissolution performance and water solubility, and improves the bioavailability; moreover, the novel crystal form of epalrestat has excellent fluidity, the angle of repose can reach below 26 degrees, the compression coefficients are all less than 10 percent, the Hausner ratio is between 1.00 and 1.11, and the novel crystal form of epalrestat is suitable for being used as a raw material medicine for producing a prodrug or a pharmaceutical preparation of the raw material medicine.)

1. A novel crystal form of epalrestat, which is characterized in that the X-ray powder diffraction pattern thereof has characteristic diffraction peaks at diffraction angles 2 theta of 6.39 +/-0.2 degrees, 7.57 +/-0.2 degrees, 12.69 +/-0.2 degrees, 14.67 +/-0.2 degrees, 15.04 +/-0.2 degrees, 21.79 +/-0.2 degrees, 24.36 +/-0.2 degrees, 25.59 +/-0.2 degrees, 27.30 +/-0.2 degrees and 31.48 +/-0.2 degrees, wherein the relative intensity of the peak at 6.39 +/-0.2 degrees is strongest.

2. The novel form of epalrestat of claim 1 wherein the novel form of epalrestat further has an X-ray powder diffraction pattern with characteristic diffraction peaks at diffraction angles 2 Θ of 13.30 ± 0.2 °, 16.57 ± 0.2 °, 19.59 ± 0.2 °, 26.59 ± 0.2 °, 30.08 ± 0.2 °, 31.79 ± 0.2 ° and 37.85 ± 0.2 °.

3. The novel crystal form of epalrestat according to any one of claims 1-2, characterized in that the X-ray powder diffraction pattern thereof has the peak heights and relative intensities corresponding to the diffraction angles 2 theta shown in Table 1:

TABLE 1 Peak height and relative intensity for diffraction Angle 2 θ

4. The novel crystal form of epalrestat according to claim 1 or 2, characterized in that the infrared absorption spectrum has characteristic peaks at the following positions: 3252cm^-1，1747cm^-1，1686cm^-1，1563cm^-1，1417cm^-1，1362cm^-1，1339cm^-1，1184cm^-1，1117cm^-1，1066cm^-1，933cm^-1，884cm^-1，739cm^-1，694cm^-1，587cm^-1，550cm^-1，515cm^-1And 479cm^-1。

5. The novel crystal form of epalrestat according to claim 1 or 2, characterized in that the differential scanning calorimetry of the novel crystal form of epalrestat has an endothermic peak at 225.16-227.50 ℃.

6. The novel crystal form of epalrestat according to claim 1 or 2, characterized in that the thermogravimetric analysis pattern is a stable straight line in the 90-225 ℃ region, and the sample begins to decompose after 240 ± 5 ℃.

7. The method for preparing the novel epalrestat crystal form according to any one of claims 1 to 6, which is characterized by comprising the following steps:

carrying out condensation reaction on 3-carboxymethyl rhodanine and alpha-methyl cinnamaldehyde in a reaction system comprising a reaction solvent, an organic alkaline catalyst and a phase transfer catalyst to obtain a condensation reaction feed liquid;

mixing the condensation reaction liquid with acid liquor to obtain a crude epalrestat product;

and mixing the crude epalrestat product, an alcohol solvent and an acid solution, and refining to obtain the novel crystal form of epalrestat.

8. The method according to claim 7, wherein the temperature of the condensation reaction is 50 to 70 ℃ and the time of the condensation reaction is 1 to 3 hours.

9. The preparation method of claim 7, wherein in the mixing of the crude epalrestat product, the alcohol solvent and the acid solution, the molar ratio of epalrestat in the acid solution and the crude epalrestat product is not less than 1: 1.

10. use of a novel crystal form of epalrestat according to any one of claims 1 to 6 or a novel crystal form of epalrestat according to any one of claims 7 to 9 for the manufacture of a medicament for an aldose reductase inhibitor.

Technical Field

The invention relates to the technical field of medicines, in particular to a novel crystal form of epalrestat, a preparation method and application thereof.

Background

Epalrestat (Epalrestat), a novel aldose reductase inhibitor developed by japanese nova corporation, was first introduced to the market in japan in 1992 for the treatment of diabetic complications such as neuropathy, corneal epithelial disorders, retinopathy, and microangiopathy. One of the causes of diabetic complications is osmotic pressure abnormality caused by hyperactivity of polyol metabolism activity, and aldose inhibitors can effectively treat diabetic complications by inhibiting rate-limiting enzymes of conversion of glucose to sorbitol in polyol metabolism, and fundamentally solve partial tissue osmotic pressure abnormality.

Epalrestat, chemical name is 5- [ (1Z,2E) -2-methyl-3-phenylpropylidene ] -2-sulfo-2, 4-thiazolidinedione-3-acetic acid, and chemical structure is as follows:

there are three epalrestat crystal forms reported in the existing literature, namely an epalrestat A crystal form, an epalrestat B crystal form and an epalrestat C crystal form.

Patent JP20044210702S and patent JP20044210703A disclose methods for preparing crystal forms of epalrestat a and epalrestat B, respectively; patent CN105272934A discloses a preparation method of epalrestat C crystal form.

In addition, epalrestat solvate and epalrestat eutectic are reported in the literature: patent JP2017-43605A reports DMF solvate of epalrestat; patent US2009051693 discloses a preparation method of epalrestat betaine eutectic; patent CN103951634B discloses a preparation method of epalrestat crystal salt hydrate and hydroxypiperidine eutectic.

The phenomenon that one drug molecule forms multiple crystal forms is called drug polymorphism. Different crystal forms of the same medicament may have obvious difference in aspects of appearance, solubility, melting point, dissolution rate, bioequivalence and the like, thereby influencing the stability, bioavailability and curative effect of the medicament, and the phenomenon is particularly remarkable in the aspect of oral solid preparations. The medicine polymorphism is one of important factors influencing the quality and clinical efficacy of medicines, so the medicine polymorphism and the preparation technology thereof have very important significance for solid medicine preparations.

Epalrestat has poor water solubility, and the different solubilities of different crystal forms can influence the dissolution of the Epalrestat in a pharmaceutical composition, thereby influencing the bioavailability of the drug in a human body. Therefore, the research and the preparation of the novel crystal form of the epalrestat have very important significance.

Disclosure of Invention

In view of the above, the present invention aims to provide a novel crystal form of epalrestat, and a preparation method and applications thereof. The novel crystal form of epalrestat provided by the invention has excellent water solubility and dissolution performance, and improves the bioavailability of epalrestat.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a novel crystal form of epalrestat, wherein an X-ray powder diffraction pattern of the novel crystal form has characteristic diffraction peaks at diffraction angles 2 theta of 6.39 +/-0.2 degrees, 7.57 +/-0.2 degrees, 12.69 +/-0.2 degrees, 14.67 +/-0.2 degrees, 15.04 +/-0.2 degrees, 21.79 +/-0.2 degrees, 24.36 +/-0.2 degrees, 25.59 +/-0.2 degrees, 27.30 +/-0.2 degrees and 31.48 +/-0.2 degrees, wherein the relative intensity of the peak at 6.39 +/-0.2 degrees is strongest.

Preferably, the X-ray powder diffraction pattern of the novel crystal form of epalrestat also has characteristic diffraction peaks at diffraction angles 2 theta of 13.30 +/-0.2 degrees, 16.57 +/-0.2 degrees, 19.59 +/-0.2 degrees, 26.59 +/-0.2 degrees, 30.08 +/-0.2 degrees, 31.79 +/-0.2 degrees and 37.85 +/-0.2 degrees.

Preferably, the peak height and relative intensity corresponding to the diffraction angle 2 theta in the X-ray powder diffraction pattern of the novel crystal form of epalrestat are shown in table 1:

TABLE 1 Peak height and relative intensity for diffraction Angle 2 θ

Preferably, the novel crystal form of epalrestat has characteristic peaks in the following positions in the infrared absorption spectrum: 3252cm^-1，1747cm^-1，1686cm^-1，1563cm^-1，1417cm^-1，1362cm^-1，1339cm^-1，1184cm^-1，1117cm^-1，1066cm^-1，933cm^-1，884cm^-1，739cm^-1，694cm^-1，587cm^-1，550cm^-1，515cm^-1And 479cm^-1。

Preferably, the differential scanning calorimetry analysis map of the novel crystal form of epalrestat has an endothermic peak at 225.16-227.50 ℃.

Preferably, the thermogravimetric analysis spectrum of the novel epalrestat crystal form is a stable straight line in a region of 90-225 ℃, and a sample begins to decompose after 240 +/-5 ℃.

The invention also provides a preparation method of the novel crystal form of epalrestat, which comprises the following steps:

carrying out condensation reaction on 3-carboxymethyl rhodanine and alpha-methyl cinnamaldehyde in a reaction system comprising a reaction solvent, an organic alkaline catalyst and a phase transfer catalyst to obtain a condensation reaction feed liquid;

mixing the condensation reaction liquid with acid liquor to obtain a crude epalrestat product;

and mixing the crude epalrestat product, an alcohol solvent and an acid solution, and refining to obtain the novel crystal form of epalrestat.

Preferably, the temperature of the condensation reaction is 50-70 ℃, and the time of the condensation reaction is 1-3 h.

Preferably, the epalrestat crude product, the alcohol solvent and the acid solution are mixed, and the molar ratio of the acid solution to the epalrestat in the epalrestat crude product is more than or equal to 1: 1.

the invention also provides the novel crystal form of epalrestat in the technical scheme or the application of the novel crystal form of epalrestat in the technical scheme in preparing aldose reductase inhibitor medicines.

The invention provides a novel crystal form of epalrestat, wherein an X-ray powder diffraction pattern of the novel crystal form has characteristic diffraction peaks at diffraction angles 2 theta of 6.39 +/-0.2 degrees, 7.57 +/-0.2 degrees, 12.69 +/-0.2 degrees, 14.67 +/-0.2 degrees, 15.04 +/-0.2 degrees, 21.79 +/-0.2 degrees, 24.36 +/-0.2 degrees, 25.59 +/-0.2 degrees, 27.30 +/-0.2 degrees and 31.48 +/-0.2 degrees, wherein the relative intensity of the peak at 6.39 +/-0.2 degrees is strongest. The novel crystal form of epalrestat provided by the invention has excellent water solubility and dissolution performance, and improves the bioavailability of epalrestat; in addition, the novel crystal form of epalrestat provided by the invention has very good fluidity, the angle of repose can reach below 26 degrees, the compression coefficients are all less than 10%, and the Hausner ratio is all between 1.00-1.11, so that the novel crystal form of epalrestat is very suitable for being used as a raw material medicine for producing a prodrug or a pharmaceutical preparation of epalrestat.

The invention also provides a preparation method of the novel crystal form of epalrestat, which comprises the following steps: carrying out condensation reaction on 3-carboxymethyl rhodanine and alpha-methyl cinnamaldehyde in a reaction system comprising a reaction solvent, an organic alkaline catalyst and a phase transfer catalyst to obtain a condensation reaction feed liquid; mixing the condensation reaction liquid with acid liquor to obtain a crude epalrestat product; and mixing the crude epalrestat product, an alcohol solvent and an acid solution, and refining to obtain the novel crystal form of epalrestat. The preparation method provided by the invention can successfully prepare the novel crystal form of epalrestat, and is simple to operate.

The invention also provides the novel crystal form of epalrestat in the technical scheme or the application of the novel crystal form of epalrestat in the technical scheme in preparing aldose reductase inhibitor medicines. The aldose reductase inhibitor medicine obtained by utilizing the novel crystal form of epalrestat provided by the invention has better dissolution property.

Drawings

FIG. 1 is an X-ray powder diffraction (XRD) pattern of a novel crystalline form of epalrestat according to example 1 of the present invention;

FIG. 2 is an infrared absorption (IR) spectrum of a novel crystalline form of epalrestat according to example 1 of the present invention;

FIG. 3 is a Differential Scanning Calorimetry (DSC) profile of a novel crystalline form of epalrestat according to example 1 of the present invention;

FIG. 4 is a thermogravimetric analysis (TGA) profile of a new crystalline form of epalrestat according to example 1 of the present invention;

FIG. 5 shows the NMR spectra of epalrestat of example 1¹H-NMR) chart;

FIG. 6 is a High Performance Liquid Chromatography (HPLC) spectrum of a novel crystal form of epalrestat in example 1 of the present invention;

FIG. 7 is a photograph of the crystal habit of the novel crystal form high power microscope of epalrestat in example 1 of the present invention;

FIG. 8 is a graph showing the dissolution profiles of the self-coated tablets and the original coated tablets prepared with the new crystal form of epalrestat of example 1 of the present invention in a 0.1 wt% sodium dodecylsulfate solution at pH 6.8.

Detailed Description

The invention provides a novel crystal form of epalrestat, wherein an X-ray powder diffraction pattern of the novel crystal form is shown in figure 1, and characteristic diffraction peaks exist at diffraction angles 2 theta of 6.39 +/-0.2 degrees, 7.57 +/-0.2 degrees, 12.69 +/-0.2 degrees, 14.67 +/-0.2 degrees, 15.04 +/-0.2 degrees, 21.79 +/-0.2 degrees, 24.36 +/-0.2 degrees, 25.59 +/-0.2 degrees, 27.30 +/-0.2 degrees and 31.48 +/-0.2 degrees, wherein the relative intensity of the peak at 6.39 +/-0.2 degrees is strongest. In the present invention, the X-ray powder diffraction pattern for obtaining the novel crystal form of epalrestat preferably uses Cu-Ka radiation.

In the present invention, the X-ray powder diffraction pattern of the novel crystal form of epalrestat preferably also has characteristic diffraction peaks at diffraction angles 2 theta of 13.30 +/-0.2 degrees, 16.57 +/-0.2 degrees, 19.59 +/-0.2 degrees, 26.59 +/-0.2 degrees, 30.08 +/-0.2 degrees, 31.79 +/-0.2 degrees, 37.85 +/-0.2 degrees.

In the invention, Cu-Kalpha radiation is used in the novel crystal form of epalrestat, the X-ray powder diffraction pattern is shown in figure 1, and the peak height and relative intensity corresponding to the diffraction angle 2 theta are shown in table 1.

TABLE 1 Peak height and relative intensity for diffraction Angle 2 θ

In the invention, the infrared absorption spectrum of the novel epalrestat crystal form is shown in figure 2, and the infrared absorption spectrum of the novel epalrestat crystal form has characteristic peaks at the following positions: 3252cm^-1，1747cm^-1，1686cm^-1，1563cm^-1，1417cm^-1，1362cm^-1，1339cm^-1，1184cm^-1，1117cm^-1，1066cm^-1，933cm^-1，884cm^-1，739cm^-1，694cm^-1，587cm^-1，550cm^-1，515cm^-1And 479cm^-1。

In the invention, a differential scanning calorimetry analysis map of the novel crystal form of epalrestat is shown in figure 3, and the differential scanning calorimetry analysis map of the novel crystal form of epalrestat has an endothermic peak at 225.16-227.50 ℃.

In the invention, the thermogravimetric analysis spectrum of the novel crystal form of epalrestat is shown in figure 4; the thermogravimetric analysis spectrum of the novel epalrestat crystal form is a stable straight line in a 90-225 ℃ region, and a sample begins to decompose after 240 +/-5 ℃.

The invention also provides a preparation method of the novel crystal form of epalrestat, which comprises the following steps:

carrying out condensation reaction on 3-carboxymethyl rhodanine and alpha-methyl cinnamaldehyde in a reaction system comprising a reaction solvent, an organic alkaline catalyst and a phase transfer catalyst to obtain a condensation reaction feed liquid;

mixing the condensation reaction liquid with acid liquor to obtain a crude epalrestat product;

and mixing the crude epalrestat product, an alcohol solvent and an acid solution, and refining to obtain the novel crystal form of epalrestat.

In the present invention, the starting materials used in the present invention are preferably commercially available products unless otherwise specified.

The invention carries out condensation reaction on 3-carboxymethyl rhodanine and alpha-methyl cinnamaldehyde in a reaction system comprising a reaction solvent, an organic alkaline catalyst and a phase transfer catalyst to obtain a condensation reaction feed liquid.

In the present invention, the reaction solvent is preferably water, and the water is preferably purified water. In the present invention, the organic basic catalyst preferably comprises 3-dimethylaminopropylamine. In the present invention, the phase transfer catalyst preferably comprises polyethylene glycol, and the polyethylene glycol preferably comprises one or more of polyethylene glycol 200, polyethylene glycol 400 and polyethylene glycol 800, and further preferably polyethylene glycol 400.

In the present invention, the molar ratio of the 3-carboxymethyl rhodanine to the α -methyl cinnamaldehyde is preferably 1: (1.1 to 1.3), more preferably 1: 1.2.

in the invention, the molar ratio of the organic basic catalyst to the 3-carboxymethyl rhodanine is preferably (7-9): 10, more preferably 8: 10.

in the invention, the dosage ratio of the phase transfer catalyst to the 3-carboxymethyl rhodanine is preferably (70-90) mL: 80mmol, more preferably 80 mL: 80 mmol.

In the present invention, the ratio of the amount of the reaction solvent to the amount of 3-carboxymethyl rhodanine is preferably (300-340) mL: 80mmol, more preferably 320 mL: 80 mmol.

In the present invention, the 3-carboxymethyl rhodanine, the α -methyl cinnamaldehyde, the reaction solvent, the organic basic catalyst and the phase transfer catalyst are preferably added in the order of: mixing a reaction solvent and a phase transfer catalyst to obtain a phase transfer catalyst solution; sequentially adding 3-carboxymethyl rhodanine and alpha-methyl cinnamaldehyde to the phase transfer catalyst solution; then, an organic basic catalyst is added dropwise. In the invention, the dropping speed of the organic basic catalyst is preferably 1-10 mL/min, and more preferably 5 mL/min.

In the invention, the condensation reaction temperature is preferably 50-70 ℃, and more preferably 60 ℃; the time of the condensation reaction is preferably 1-3 h, and more preferably 2 h; the time of the condensation reaction is preferably measured from the completion of the dropwise addition of the organic basic catalyst. In the present invention, the condensation reaction is preferably performed under stirring conditions, and the rotation speed of the stirring is preferably 100 to 400rpm, and more preferably 300 rpm.

After the condensation reaction feed liquid is obtained, the condensation reaction feed liquid and the acid liquid are mixed to obtain the crude epalrestat product.

In the invention, after the condensation reaction is finished, a condensation reaction feed liquid can be obtained; after the condensation reaction is finished, preferably, heating of the condensation reaction system is stopped, and an acid solution is added into the condensation reaction feed liquid.

In the present invention, the acid solution preferably includes an inorganic acid and/or an organic acid; the inorganic acid preferably comprises one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and hydrobromic acid, and is further preferably hydrochloric acid, and the mass percentage of the hydrochloric acid is preferably 36-38%. In the present invention, the organic acid preferably includes one or more of formic acid, acetic acid, trifluoroacetic acid, lactic acid, benzoic acid, succinic acid, fumaric acid, maleic acid, citric acid, tartaric acid, succinic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid.

In the invention, in the mixing of the condensation reaction feed liquid and the acid liquid, the mol ratio of the acid liquid to the organic alkaline catalyst is preferably not less than 1: 1.

in the present invention, after the condensation reaction feed liquid and the acid liquid are mixed, it is preferable that the method further comprises: after the mixed system of the condensation reaction feed liquid and the acid liquid is cooled to room temperature, filtering; carrying out first washing and first drying on the obtained solid to obtain a crude epalrestat product

In the present invention, the reagent of the first washing is preferably purified water, and the amount of the purified water used is not particularly limited; the first washing mode is preferably rinsing. In the present invention, the first drying method is preferably vacuum drying; the temperature of the vacuum drying is preferably 40 ℃, and the time is preferably 2.0 h.

After the crude epalrestat product is obtained, the crude epalrestat product, an alcohol solvent and an acid solution are mixed and refined to obtain the novel crystal form of epalrestat.

In the present invention, the alcohol solvent preferably includes a monohydric alcohol, and the monohydric alcohol preferably includes one or more of methanol, ethanol, isopropanol, and n-butanol, and further preferably methanol. In the present invention, the type of the acid solution is preferably the same as that of the acid solution described in the above technical scheme, and is not described herein again.

In the invention, the dosage ratio of the crude epalrestat product to the alcohol solvent is preferably 1 g: (5-50) mL, more preferably 16 g: 100 mL. In the invention, in the mixing of the crude epalrestat product, the alcohol solvent and the acid solution, the molar ratio of the epalrestat in the acid solution and the crude epalrestat product is preferably more than or equal to 1: 1.

in the invention, the mixing sequence of the crude epalrestat, the alcohol solvent and the acid solution is preferably as follows: and dispersing the crude epalrestat product in an alcohol solvent, and then dropwise adding an acid solution under the condition of stirring. In the invention, the dropping speed of the acid solution is preferably 1-10 mL/min, and more preferably 5 mL/min. In the present invention, the rotation speed of the stirring is preferably 100 to 400rpm, and more preferably 300 rpm.

In the invention, the refining is preferably carried out under the condition of heating and stirring, the temperature of the heating and stirring is preferably 60-80 ℃, and the time is preferably 2.0 h. In the present invention, the rotation speed of the heating and stirring is preferably the same as the rotation speed of the stirring for dropping the acid solution, and will not be described herein again.

After the refining, the invention preferably further comprises post-treatment of the obtained refining system, wherein the post-treatment preferably comprises cooling the refining system to room temperature, filtering, and sequentially carrying out second washing and second drying on the obtained solid to obtain the novel crystal form of epalrestat.

In the present invention, the second washing reagent is preferably anhydrous methanol, and the amount of the second washing reagent is not particularly limited; the second washing mode is preferably rinsing. In the invention, the second drying mode is preferably vacuum drying, and the temperature of the vacuum drying is preferably 30-60 ℃, and more preferably 40 ℃; the time is preferably 1.0 to 6.0 hours, and more preferably 2.0 hours.

The invention also provides the application of the novel crystal form of epalrestat in the technical scheme or the novel crystal form of epalrestat obtained by the preparation method in the technical scheme in preparing aldose reductase inhibitor medicines.

In the present invention, the aldose reductase inhibitor drug is preferably an aldose reductase inhibitor pharmaceutical composition.

In the present invention, the dosage form of the aldose reductase inhibitor pharmaceutical composition is preferably, but not exclusively, tablets, capsules and injections.

In the present invention, the pharmaceutical composition of aldose reductase inhibitor preferably further comprises a pharmaceutically acceptable carrier or excipient.

The following examples are provided to illustrate the novel crystal form of epalrestat and the preparation method and application thereof in detail, but they should not be construed as limiting the scope of the present invention.

Example 1

A1000 mL three-neck round-bottom flask was charged with 320mL of purified water and 80mL of polyethylene glycol 40080 in this order, and then 3-carboxymethylrhodanine (15.3g, 80mmol) and α -methylcinnamaldehyde (14.0g, 96mmol) were added at room temperature with stirring, and 3-dimethylaminopropylamine (8.0mL, 64mmol) was added dropwise at a rate of 5mL/min after the addition. After the dropwise addition, the temperature is raised to 60 ℃ and stirring is continued under heat preservation (the rotating speed is 300rpm) for 2.0 h. And closing the heating and naturally cooling, and simultaneously dropwise adding 20.0mL of concentrated hydrochloric acid into the reaction system. And (3) cooling the reaction system to 25 ℃, filtering, leaching a filter cake by using 100mL of purified water, and drying for 2.0h in vacuum at 40 ℃ to obtain a yellow solid crude epalrestat product (24.5g, 96%).

Suspending crude epalrestat (16.0g, 50mmol) in 100mL of anhydrous methanol in a 250mL round-bottom flask, stirring at room temperature (the rotating speed is 300rpm), and dropwise adding 5mmol of concentrated hydrochloric acid at the speed of 5 mL/min; heating to 60 ℃, and continuing to keep the temperature and stir for 2.0 h. And (3) closing heating and naturally cooling, cooling the reaction system to 25 ℃, filtering, leaching a filter cake by using 20mL of anhydrous methanol, and carrying out vacuum drying at 40 ℃ for 2.0h to obtain 13.9g of yellow solid epalrestat, wherein the yield is 87%, the purity is 99.868%, the compression coefficient (%) is 25.6 degrees of the angle of repose is 9, and the Hausner ratio is 1.05.

The X-ray powder diffraction (XRD) pattern of the novel epalrestat crystal form obtained in the example 1 of the invention by using Cu-Kalpha radiation is shown in figure 1; as can be seen from fig. 1: characteristic diffraction peaks exist at diffraction angles 2 theta of 6.39 +/-0.2 degrees, 7.57 +/-0.2 degrees, 12.69 +/-0.2 degrees, 13.30 +/-0.2 degrees, 14.67 +/-0.2 degrees, 15.04 +/-0.2 degrees, 16.57 +/-0.2 degrees, 19.59 +/-0.2 degrees, 21.79 +/-0.2 degrees, 24.36 +/-0.2 degrees, 25.59 +/-0.2 degrees, 26.59 +/-0.2 degrees, 27.30 +/-0.2 degrees, 30.08 +/-0.2 degrees, 31.48 +/-0.2 degrees, 31.79 +/-0.2 degrees and 37.85 +/-0.2 degrees; the relative intensity of the peak at 6.39 +/-0.2 degrees is the strongest; the crystal form is proved to be a new crystal form of epalrestat.

FIG. 2 is an infrared absorption (IR) spectrum of a novel crystalline form of epalrestat according to example 1 of the present invention; as can be seen from fig. 2: the infrared absorption spectrum contains characteristic peaks at the following positions: 3252cm^-1，1747cm^-1，1686cm^-1，1563cm^-1，1417cm^-1，1362cm^-1，1339cm^-1，1184cm^-1，1117cm^-1，1066cm^-1，933cm^-1，884cm^-1，739cm^-1，694cm^-1，587cm^-1，550cm^-1，515cm^-1And 479cm^-1(ii) a The crystal form is proved to be a new crystal form of epalrestat.

FIG. 3 is a Differential Scanning Calorimetry (DSC) profile of a novel crystalline form of epalrestat according to example 1 of the present invention; as can be seen from fig. 3: the novel crystal form of epalrestat has an endothermic peak at 225.16-227.50 ℃, which is the melting peak temperature, and shows that the novel crystal form of epalrestat has excellent thermal stability.

FIG. 4 is a thermogravimetric analysis (TGA) profile of a new crystalline form of epalrestat according to example 1 of the present invention; as can be seen from fig. 4: the crystal form is a stable straight line in a temperature range of 90-225 ℃, which shows that the novel crystal form of epalrestat does not contain adsorbed water or volatile substances and has excellent thermal stability; the sample began to decompose after approximately 240 ± 5 ℃.

FIG. 5 shows the NMR spectra of epalrestat of example 1¹H-NMR), as can be seen from fig. 5: the substance obtained in example 1 was epalrestat.

Precisely weighing 10mg of the epalrestat new crystal form obtained in example 1, placing the epalrestat new crystal form in a 100mL measuring flask, adding 30mL of methanol for ultrasonic dissolution, adding a mobile phase (a mixed solution of the methanol and an acetic acid solution with the volume concentration of 0.4% in a volume ratio of 65: 35) for dilution to a scale, and shaking up to obtain an upper computer sample; performing purity detection on the sample on the computer by using a high performance liquid chromatography; the parameters of the high performance liquid chromatography include: octadecylsilane chemically bonded silica is used as a filling agent; the volume ratio of methanol to acetic acid solution with volume concentration of 0.4% is 65: 35 as a mobile phase for isocratic elution; the flow rate is 1.0 mL/min; the detection wavelength is 290 nm; the column temperature is 30 ℃; the injection volume was 20. mu.L. The results are shown in FIG. 6; as can be seen from fig. 6: the purity of the novel crystal form of epalrestat obtained in example 1 is up to 99.868%, and the quantity of impurities is small and is below 0.1%.

FIG. 7 is a photograph showing the crystal habit of high power microscope of the novel crystal form of epalrestat according to example 1 of the present invention, and it can be seen from FIG. 7 that: the crystal habit of the novel crystal form of epalrestat is a rhombus flaky crystal habit.

And (3) measuring the solubility:

taking 10mg of the novel epalrestat crystal form obtained in example 1, placing the novel epalrestat crystal form in a 250mL triangular flask with a plug, adding 100mL of water, carrying out ultrasonic treatment for 30min (operation in a dark place during the ultrasonic treatment), standing the mixture to room temperature after the ultrasonic treatment is finished, and filtering the mixture to obtain a subsequent filtrate as a sample solution.

Preparing a reference substance solution: taking 10mg of a reference substance, accurately weighing, placing in a 100mL measuring flask, adding 30mL of methanol for ultrasonic dissolution, adding flow for dilution to the scale, and shaking up.

The detection conditions of the high performance liquid chromatography are as follows: octadecylsilane chemically bonded silica is used as a filling agent, and methanol and an acetic acid solution with volume concentration of 0.4% are mixed according to a volume ratio of 65: 35 as a mobile phase for isocratic elution; the flow rate is 1.0 mL/min; the detection wavelength is 290 nm; the column temperature is 30 ℃; the injection volume was 20. mu.L.

Precisely measuring the test solution and the reference solution, respectively injecting into a high performance liquid chromatograph, detecting according to the detection conditions of the high performance liquid chromatograph, and recording the chromatogram until the retention time of the main component peak is 3 times. And calculating the content of epalrestat in the test sample by peak area according to an external standard method.

The results were: the solubility of the control in water was 1.827. mu.g/mL; the solubility of the novel crystal form of epalrestat in water is 2.307 mug/mL.

In-vitro dissolution curve and stability research of coated tablets prepared from novel epalrestat crystal form

Epalrestat is BCS II, the plasma concentration of the epalrestat tablet can be measured 60 minutes after the epalrestat tablet is orally taken, the absorption is better, and the absorption part of the epalrestat tablet is mainly in the intestinal tract. Therefore, the dissolution curve showing the most specific correlation between the epalrestat tablets in vivo and in vitro was a medium pH 6.8 solution.

The epalrestat original research product coated tablet is purchased from Xiaoye pharmaceutical industry Co., Ltd, and has the specification of 50mg 10 s; the novel crystal form of epalrestat obtained in example 1 is used as a raw material, and a self-ground coated tablet is prepared according to the preparation method of an epalrestat original ground coated tablet.

The self-coated tablet and the original coated tablet were placed in a 0.1 wt% sodium dodecylsulfate solution having a pH of 6.8, and the dissolution curves thereof were measured, and the results are shown in FIG. 8. As can be seen from fig. 8: the in vitro bioequivalence of the self-ground coated tablet and the original ground coated tablet.

The self-ground coated tablets and the original ground coated tablets were placed in a constant temperature and humidity cabinet at a temperature of 40. + -. 2 ℃ and a humidity of 75. + -. 5% to conduct an accelerated test, and the results are shown in Table 2.

TABLE 2 accelerated test results of self-ground coated tablets and original ground coated tablets

As can be seen from table 2: the quality and stability of the self-developed coated tablet prepared from the novel crystal form of epalrestat are superior to those of the original coated tablet.

Example 2

A1000 mL three-neck round-bottom flask was charged with 320mL of purified water and 80mL of polyethylene glycol 40080 in this order, and then 3-carboxymethylrhodanine (15.3g, 80mmol) and α -methylcinnamaldehyde (14.0g, 96mmol) were added at room temperature with stirring, and 3-dimethylaminopropylamine (8.0mL, 64mmol) was added dropwise at a rate of 5mL/min after the addition. After the dropwise addition, the temperature is raised to 60 ℃ and stirring is continued under heat preservation (the rotating speed is 300rpm) for 2.0 h. And closing the heating and naturally cooling, and simultaneously dropwise adding 20.0mL of concentrated hydrochloric acid into the reaction system. And (3) cooling the reaction system to 25 ℃, filtering, leaching a filter cake by using 100mL of purified water, and drying for 2.0h in vacuum at 40 ℃ to obtain a yellow solid crude epalrestat product (24.5g, 96%).

Suspending crude epalrestat (16.0g, 50mmol) in 120mL isopropanol in a 250mL round-bottom flask, stirring at room temperature (the rotating speed is 300rpm), and dropwise adding 5mmol of concentrated hydrochloric acid at the speed of 5 mL/min; heating to 80 ℃, and continuing to keep the temperature and stir for 2.0 h. And (3) closing heating and naturally cooling, cooling the reaction system to 25 ℃, filtering, leaching a filter cake by using 20mL of isopropanol, and carrying out vacuum drying at 40 ℃ for 2.0h to obtain 12.5g of yellow solid epalrestat, wherein the yield is 78%, the purity is 99.778%, the compression coefficient (%) is 25.8 ℃ of the angle of repose is 9, and the Hausner ratio is 1.06.

The crystal form is the same new crystal form as the crystal form in the example 1 through X-ray powder diffraction test.

Example 3

A1000 mL three-neck round-bottom flask was charged with 320mL of purified water and 80mL of polyethylene glycol 40080 in this order, and then 3-carboxymethylrhodanine (15.3g, 80mmol) and α -methylcinnamaldehyde (14.0g, 96mmol) were added at room temperature with stirring, and 3-dimethylaminopropylamine (8.0mL, 64mmol) was added dropwise at a rate of 5mL/min after the addition. After the dropwise addition, the temperature is raised to 60 ℃ and stirring is continued under heat preservation (the rotating speed is 300rpm) for 2.0 h. And closing the heating and naturally cooling, and simultaneously dropwise adding 20.0mL of concentrated hydrochloric acid into the reaction system. And (3) cooling the reaction system to 25 ℃, filtering, leaching a filter cake by using 100mL of purified water, and drying for 2.0h in vacuum at 40 ℃ to obtain a yellow solid crude epalrestat product (24.5g, 96%).

Suspending crude epalrestat (16.0g, 50mmol) in 120mL of absolute ethyl alcohol in a 250mL round-bottom flask, stirring at room temperature (the rotating speed is 300rpm), and dropwise adding 5mmol of concentrated hydrochloric acid at the speed of 5 mL/min; heating to 80 ℃, and continuing to keep the temperature and stir for 2.0 h. And (3) closing heating and naturally cooling, cooling the reaction system to 25 ℃, filtering, leaching a filter cake by using 20mL of absolute ethyl alcohol, and carrying out vacuum drying at 60 ℃ for 2.0h to obtain 12.8g of yellow solid epalrestat, wherein the yield is 80%, the purity is 99.798%, the compression coefficient (%) of the angle of repose is 25.1 degrees, and the Hausner ratio is 1.02.

The crystal form is the same new crystal form as the crystal form in the example 1 through X-ray powder diffraction test.

Example 4

A1000 mL three-neck round-bottom flask was charged with 320mL of purified water and 80mL of polyethylene glycol 40080 in this order, and then 3-carboxymethylrhodanine (15.3g, 80mmol) and α -methylcinnamaldehyde (14.0g, 96mmol) were added at room temperature with stirring, and 3-dimethylaminopropylamine (8.0mL, 64mmol) was added dropwise at a rate of 5mL/min after the addition. After the dropwise addition, the temperature is raised to 60 ℃ and stirring is continued under heat preservation (the rotating speed is 300rpm) for 2.0 h. And closing the heating and naturally cooling, and simultaneously dropwise adding 20.0mL of concentrated hydrochloric acid into the reaction system. And (3) cooling the reaction system to 25 ℃, filtering, leaching a filter cake by using 100mL of purified water, and drying for 2.0h in vacuum at 40 ℃ to obtain a yellow solid crude epalrestat product (24.5g, 96%).

Suspending crude epalrestat (16.0g, 50mmol) in 150mL of anhydrous methanol in a 250mL round-bottom flask, stirring at room temperature (the rotating speed is 300rpm), and dropwise adding 5mmol of concentrated hydrochloric acid at the speed of 5 mL/min; heating to 60 ℃, and continuing to keep the temperature and stir for 2.0 h. And (3) closing heating and naturally cooling, cooling the reaction system to 25 ℃, filtering, leaching a filter cake by using 20mL of anhydrous methanol, and carrying out vacuum drying at 60 ℃ for 2.0h to obtain 13.4g of yellow solid epalrestat, wherein the yield is 84%, the purity is 99.818%, the compression coefficient (%) of the angle of repose is 25.7 degrees is 9, and the Hausner ratio is 1.09.

The crystal form is the same new crystal form as the crystal form in the example 1 through X-ray powder diffraction test.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.