Separation and purification method of melogabalin besylate impurity I

Abstract

The invention discloses a separation and purification method of a melogabalin benzene sulfonate impurity I. The invention aims to protect a separation and purification method of the impurity I, establish a detection method and analyze the impurity content so as to ensure the product quality and medication safety of melogabalin besylate. The invention provides a method for separating and purifying the impurity I. The liquid phase purity of the impurity I is higher than 95.0%, and the method has important practical significance in preparation of impurity reference substances.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pharmaceutical chemical synthesis, and particularly relates to a separation and purification method of impurity I of mirogabalin besylate. BACKGROUND

[0002] Mirogabalin besylate has the chemical name of [(1R, 5S, 6S)-6-(aminomethyl)-3-ethylbicyclo[3.2.0]hept-3-en-6-yl] benzenesulfonate, and a structural formula as follows:

[0003]

[0004] Mirogabalin besylate is an oral gabapentinoid drug developed by Daiichi Sankyo for treating peripheral neuropathic pain (PNP), including diabetic PNP and post-herpetic neuralgia. Mirogabalin besylate is a new gabapentinoid anticonvulsant with selectivity to the alpha2delta subunit, and shows a more persistent analgesic effect due to high affinity for and slow dissociation from the alpha2delta-1 subunit in the dorsal root ganglion (DRG). In addition, it produces lower levels of central nervous system-specific adverse drug reactions (ADRs) due to low affinity for and rapid dissociation from the alpha2delta-2 subunit in the cerebellum.

[0005] Mirogabalin besylate is a small molecule drug, contains multiple chiral centers in the structure, and has cis-trans isomerism, with the configuration of the chiral center being 1R, 5S, 6S, and the cis-trans configuration of the double bond being C3 Z C4. According to patent CN104755456A, in the synthesis process of mirogabalin besylate from an intermediate containing a tert-butyl ester group by heating under the action of an acid to deprotect the tert-butyl ester group, a side reaction of double bond position isomerization easily occurs, thereby generating impurity I (compound of formula XII), and the content of the impurity in mirogabalin besylate is more than 0.5%, which affects the quality of the drug and brings hidden dangers to product safety. SUMMARY

[0006] The application aims to protect the separation and purification method of impurity I, establish a detection method, analyze the impurity content, and determine a reasonable impurity limit, so as to ensure the product quality and drug safety of mirogabalin besylate.

[0007] The application provides a separation and purification method of impurity I of mirogabalin besylate.

[0008] The technical scheme for realizing the application is as follows:

[0009] In a first aspect, the application provides a separation and purification method of impurity I of mirogabalin besylate, and the structure formula of the impurity I is as follows:

[0010]

[0011] The separation and purification method of the impurity I comprises the following steps:

[0012]

[0013] (1) the ester hydrolysis reaction of the compound of formula 1 and benzenesulfonic acid under the action of heating to obtain a crude product containing impurity I;

[0014] (2) the crude product containing impurity I is subjected to preparative separation and purification by using a DAC-100 reverse-phase preparative column to obtain impurity I.

[0015] According to the embodiment of the present application, the molar ratio of the compound of formula 1 to benzenesulfonic acid in step (1) is 1:1.1-1.3, preferably, the molar ratio of the compound of formula 1 to benzenesulfonic acid is 1:1.1.

[0016] According to the embodiment of the present application, the reaction solvent in step (1) is selected from one of toluene, acetonitrile, and acetone, preferably, the reaction solvent is toluene.

[0017] According to the embodiment of the present application, the volume ratio of the compound of formula 1 to toluene in step (1) is 1:10.

[0018] According to the embodiment of the present application, the reaction temperature in step (1) is 60-70℃.

[0019] According to the embodiment of the present application, the reaction time in step (1) is 3-4h.

[0020] According to the embodiment of the present application, the eluent mobile phase A used in step (2) is 0.1% acetic acid + 0.3% triethylamine aqueous solution, and the mobile phase B is methanol.

[0021] According to the embodiment of the present application, step (2) is gradient eluted according to the following table:

[0022]

[0023] According to the embodiment of the present application, the flow rate in step (2) is 2ml / min.

[0024] According to the embodiment of the present application, the wavelength in step (2) is 205nm.

[0025] In a second aspect, the present application provides a method for detecting impurity I of benzenesulfonic acid meloxicam, which specifically comprises the following steps:

[0026] (1) sample preparation:

[0027] Test solution: accurately weigh a certain amount of the product, dissolve and dilute with the blank solution to obtain a solution containing 0.6 mg of the test product per ml;

[0028] Impurity I reference solution: accurately weigh a certain amount of the impurity I reference product, dissolve and dilute with the blank solution to obtain a solution containing 0.6 mg of impurity I per ml;

[0029] (2) Chromatographic condition setting:

[0030] Chromatographic column: octadecylsilane bonded silica gel as the filler;

[0031] Flow rate: 0.5-1.0 ml / min;

[0032] Column temperature: 30-40℃;

[0033] Wavelength: 210-220 nm;

[0034] Injection volume: 20-40 μl;

[0035] Mobile phase: 0.01 M potassium dihydrogen phosphate solution as the mobile phase A, acetonitrile-mobile phase A=70:30 as the mobile phase B for gradient elution;

[0036] (3) Detection:

[0037] Accurately take 30 μl of each of the above solutions, inject into the liquid chromatograph, record the chromatogram, and calculate the content of impurity I in the sample according to the area normalization method.

[0038] According to the embodiments of the present application, the chromatographic column type in step (2) is C18 column, 250 mm*4.6 mm, 3 μm.

[0039] According to the embodiments of the present application, gradient elution is performed according to the following table in step (2).

[0040] Time (min) Mobile phase A (%) Mobile phase B (%) 0-5 90 10 5-25 55 45 25-30 0 100 30-40 0 100

[0041] According to the embodiments of the present application, the flow rate is set to 0.6 ml / min, the column temperature is set to 35℃, the wavelength is set to 215 nm, and the injection volume is 30 μl in step (2).

[0042] Compared with the prior art, the present application has the beneficial effects in that:

[0043] (1) The application provides a method for preparing meloxicam benzene sulfonic acid impurity I, obtaining the impurity by separation and purification, and confirming the structure of the impurity by structure confirmation, so that the structure of the compound is confirmed. The impurity is a double bond position isomerization impurity generated in the synthesis process of meloxicam benzene sulfonic acid. The application provides a separation and purification method of impurity I, and the liquid phase purity is higher than 95.0%, which has important practical significance for the preparation of impurity control samples.

[0044] (2) The application provides a method for detecting the content of impurity I in meloxicam benzene sulfonic acid. The content of impurity I in meloxicam benzene sulfonic acid is more than 0.5%, which brings hidden troubles to product safety. The implementation of the application helps to better control the quality of meloxicam benzene sulfonic acid, and has important significance for studying and controlling the production quality of drugs, and studying the adverse reactions of drug receptors. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is an HPLC chromatogram for detecting related substances of meloxicam benzene sulfonic acid.

[0046] Figure 2 is an HPLC purity detection chromatogram of impurity I of meloxicam benzene sulfonic acid. DETAILED DESCRIPTION

[0047] The application will be further described below in combination with specific embodiments and drawings. The following embodiments are only descriptive and not limiting, and the protection scope of the application cannot be limited by the following embodiments. If not otherwise specified, the raw materials used can be obtained by market or self-made.

[0048] The application relates to the preparation of meloxicam benzene sulfonic acid. The specific preparation method is as follows: (1R, 5S)-3-ethyldicyclo[3.2.0]hept-3-en-6-ketone is used as a starting material, a condensation reaction is carried out with dimethylphosphoryl tert-butyl acetate under alkaline conditions, then nitromethane is added, then the nitro group is reduced by iron powder, then chiral reagent is split, alkaline hydrolysis is carried out, and salt formation with benzene sulfonic acid is carried out, so that crude meloxicam benzene sulfonic acid is obtained. Three impurities, namely impurity G, impurity H and impurity I, are found in the crude product, the total content of the impurities is 1.26%, the content of impurity I is as high as 0.95%, and the HPLC detection result of the related substances is shown in Table 1, and the corresponding drawings are attached. Figure 1 .

[0049] Among them, impurity G and impurity H are both compounds of formula XIII shown in the specification of CN104755456A on page 7, and the difference lies in the different stereo configurations of the methyl groups, and impurity I is a compound of formula XII shown in the specification of CN104755456A on page 7.

[0050] The impurity I is extremely similar to the site of benzene sulfonic acid meloxicam, and it is difficult to remove by column chromatography and other purification methods. Therefore, it is necessary to determine the separation and purification method of the impurity, establish a detection method, analyze the impurity content, and determine the reasonable impurity limit to ensure the product quality and drug safety of benzene sulfonic acid meloxicam.

[0051] Table 1

[0052] Melagatraline benzenesulphonate Impurity G Impurity H Impurity I Time of elution min 26.468 25.293 25.441 26.075 Peak area ratio % 97.76 0.20 0.11 0.95

[0053] The impurity I is separated and purified, and its structure is confirmed, and the structure formula and name are as follows:

[0054]

[0055] The present application aims to protect the separation and purification method of the impurity I, establish a detection method, analyze the impurity content, and determine the reasonable impurity limit to ensure the product quality and drug safety of benzene sulfonic acid meloxicam.

[0056] Example 1 Preparation of impurity I

[0057] Reaction formula:

[0058]

[0059] Step one: 20g of the above compound of formula 1 and 200ml of toluene are added to a reaction bottle, 13.1g of benzene sulfonic acid is added under stirring, and the temperature is raised to 60-70℃ under stirring, and the reaction is kept for 3-4h, and the sample is monitored by TLC (developing condition: dichloromethane / methanol=20 / 1, phosphomolybdic acid coloration), until the compound of formula 1 is completely reacted. After cooling to room temperature, stirring and crystallization for 1-2h, filtration and drying, 25.1g of the crude product containing impurity I is obtained.

[0060] Step two: the above crude impurity I is dissolved in 50% water and 50% acetonitrile, and is separated by DAC-100 reverse phase preparation column, the eluent mobile phase A is 0.1% acetic acid + 0.3% triethylamine aqueous solution, and the mobile phase B is methanol, and the gradient elution is as follows:

[0061] Time (min) Mobile phase A (%) Mobile phase B (%) 0.00 95 5 5.00 95 5 5.01 85 15 10.00 85 15 100.00 65 35

[0062] The flow rate is 2ml / min, the wavelength is 205nm, the solution is sampled, the target impurity peak is received, the preparation liquid is qualified, and after desalination and freeze-drying, 0.15g of white solid, i.e. impurity I, is obtained, and the HPLC purity is 97.2%. The HPLC spectrum is shown in Figure 21H-NMR (400 MHz, DMSO) δ 5.39 (s, 1H), δ 2.84 (s, 2H), δ 2.69-2.74 (m, 2H), δ 2.27-2.42 (m, 5H), δ 1.99-2.08 (m, 3H), δ 1.33-1.37 (dd, 1H), δ 1.01-1.06 (t, 3H); 13C-NMR (150 MHz, MeOD) δ 178.710, δ 147.928, δ 126.128, δ 49.865, δ 44.651, δ 42.051, δ 39.669, δ 38.101, δ 37.351, δ 36.724, δ 23.401, δ 11.351; ESI-MS (m / z): 210.10 [M+H] + .

[0063] Preparation of Impurity I

[0064] Step one: 20 g of the above compound of formula 1 and 200 ml of toluene were added to a reaction bottle, 13.1 g of benzenesulfonic acid was added under stirring, and the temperature was raised to 60-70°C under stirring, and the reaction was kept for 3-4 h. TLC was used to monitor the reaction (developing condition: dichloromethane / methanol = 20 / 1, phosphomolybdic acid coloration), until the compound of formula 1 was completely reacted. The temperature was lowered to room temperature, and the product was crystallized under stirring for 1-2 h, filtered and dried to obtain 25.1 g of the crude product containing impurity I.

[0065] Step two: about 2 g of the crude product of impurity I was dissolved in 10 ml of a mixture of dichloromethane and methanol, and was separated and purified by column chromatography by wet loading. The eluent was dichloromethane / methanol = 100 / 1, and the polarity was gradually increased to 10 / 1. The target eluent was received in sections, combined and concentrated under reduced pressure to dryness to obtain 0.2 g of white solid, which was impurity I, and the HPLC purity was 21.5%. Traditional column chromatography separation and purification method had no effect on impurity I.

[0066] Example 2

[0067] A detection method of meloxicam, which is used for determining the content of active ingredients and related substances in meloxicam, specifically comprising the following steps:

[0068] (1) Sample preparation:

[0069] Test solution: about 6 mg of the product was accurately weighed, dissolved and diluted to the mark in a 10 ml volumetric flask with acetonitrile-0.01M potassium dihydrogen phosphate solution (10:90), and shaken well;

[0070] Impurity I control solution: about 6 mg of impurity I control was accurately weighed, dissolved and diluted to the mark in a 10 ml volumetric flask with acetonitrile-0.01M potassium dihydrogen phosphate solution (10:90), and shaken well;

[0071] (2) Chromatographic condition setting:

[0072] Chromatographic column: C18 column, 250 mm*4.6 mm, 3 μm;

[0073] Flow rate: 0.6 ml / min;

[0074] Column temperature: 35 ℃;

[0075] Wavelength: 215 nm;

[0076] Injection volume: 30 μl;

[0077] Mobile phase: Gradient elution was performed with 0.01 M potassium dihydrogen phosphate solution as mobile phase A and acetonitrile-mobile phase A = 70:30 as mobile phase B;

[0078] Time (min) Mobile phase A (%) Mobile phase B (%) 0-5 90 10 5-25 55 45 25-30 0 100 30-40 0 100

[0079] (3) Detection:

[0080] Accurately take 30 μl of each of the above solutions, inject into the liquid chromatograph, record the chromatogram, calculate the content of benzenesulfonic acid milongabalin and impurity I according to the area normalization method, the separation degree of benzenesulfonic acid milongabalin and impurity I is not less than 1.5, and the theoretical plate number calculated according to the benzenesulfonic acid milongabalin peak is not less than 10000.

Claims

1. A method for separating and purifying melogabalin besylate impurity I, characterized in that: The structural formula of the impurity I is as follows: The separation and purification method of the impurity I comprises the following steps: (1) The compound of formula 1 and benzenesulfonic acid are heated to undergo ester hydrolysis reaction to obtain a crude product containing impurity I; (2) The crude product containing impurity I was subjected to preparative separation and purification using a DAC-100 reverse phase preparative column to obtain impurity I.

2. The separation and purification method according to claim 1, wherein The molar ratio of the compound of formula 1 to benzenesulfonic acid in step (1) is 1:1.1-1.

3. Preferably, the molar ratio of the compound of formula 1 to benzenesulfonic acid is 1:1.

1.

3. The separation and purification method according to claim 1, wherein The reaction solvent described in step (1) is selected from one of toluene, acetonitrile and acetone. Preferably, the reaction solvent is toluene.

4. The separation and purification method according to claim 1, wherein The volume ratio of the compound of formula 1 to toluene in step (1) is 1:

10.

5. The separation and purification method according to claim 1, wherein The reaction temperature in step (1) is 60-70°C.

6. The separation and purification method according to claim 1, wherein The reaction time in step (1) is 3 to 4 hours.

7. The separation and purification method according to claim 1, wherein The eluent mobile phase A used in step (2) is 0.1% acetic acid + 0.3% triethylamine aqueous solution, and the mobile phase B is methanol.

8. The separation and purification method according to claim 1, wherein Step (2) gradient elution according to the table below: 。 9. The separation and purification method according to claim 1, wherein The flow rate of step (2) is 2 ml / min.

10. The separation and purification method according to claim 1, wherein The wavelength of step (2) is 205 nm.

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