Gas chromatography determination method for 2-chloro-N-methylacetamide related substances

Abstract

The invention discloses a gas chromatography determination method for related substances of 2-chloro-N-methylacetamide. A heating procedure in chromatographic conditions is as follows: the initial temperature is 75-85 DEG C, the temperature is maintained for 3 minutes, then the temperature is raised to 180 DEG C at the rate of 8-10 DEG C per minute, and finally the temperature is raised to 240 DEG C at the rate of 20-25 DEG C per minute, and the temperature is maintained for 8-12 minutes. According to the detection method disclosed by the invention, specific chromatographic conditions are adopted, and eight impurities, namely LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10 and LMS2-Z11, in the 2-chloro-N-methylacetamide can be accurately, qualitatively and quantitatively detected at the same time, so that the quality control problem of the 2-chloro-N-methylacetamide is solved; the influence on the safety and the effectiveness of chemicals and medicines taking 2-chloro-N-methylacetamide as a raw material is avoided.

Description

Technical Field

[0001] The invention relates to the field of medical detection, and in particular to a gas chromatography determination method for 2-chloro-N-methylacetamide related substances. Background Art

[0002] 2-Chloro-N-methylacetamide, also known as 2-chloroacetylmethylamine, has a CAS number of 96-30-0, a molecular formula of C3H6ClNO, and a molecular weight of 107.539. 2-Chloro-N-methylacetamide is an organic synthesis intermediate, commonly used in the synthesis of chemicals or drugs, and can be used to prepare substances such as O,O-dimethyl-S-(N-methylcarbamoylmethyl)thiophosphate and lumepirone. 2-Chloro-N-methylacetamide has a variety of synthetic routes. The conventional synthetic route is to use chloroacetyl chloride and methylamine for acylation reaction. The following impurities may be produced in this synthetic process. The structure and related information are shown in Table 1.

[0003] Table 1 2-Chloro-N-methylacetamide impurity structure and related information

[0004]

[0005] 2-Chloro-N-methylacetamide is used as a starting material for the synthesis of chemicals or drugs, and the content of each impurity affects the quality of the final product. With the increasing requirements of regulatory agencies, it is necessary to strictly control the substances related to 2-chloro-N-methylacetamide to avoid the introduction of impurities into the final product, affecting safety and effectiveness. However, there are currently no reports on the research of impurities related to 2-chloro-N-methylacetamide. It is necessary to develop a detection method to control the potential impurities of 2-chloro-N-methylacetamide to ensure the safety and effectiveness of chemicals or drugs using 2-chloro-N-methylacetamide as raw materials. Summary of the invention

[0006] To solve the above problems, the present invention provides a method for detecting related substances of 2-chloro-N-methylacetamide, which comprises the following steps:

[0007] a. Preparation of test solution: Take 2-chloro-N-methylacetamide to be tested and dissolve it in methanol to obtain the solution;

[0008] b. Preparation of system suitability solution: Take 2-chloro-N-methylacetamide reference substance and related substance reference substance and dissolve them in methanol to obtain;

[0009] c. Pipette the test solution and system suitability solution into the gas chromatograph respectively. The chromatographic conditions are as follows:

[0010] Chromatographic column: capillary column with cyanopropylphenyl-methylpolysiloxane as the stationary liquid, heating program: starting temperature 75-85°C, maintained for 3 minutes, then heated to 180°C at a rate of 8-10°C per minute, and finally heated to 240°C at a rate of 20-25°C per minute, maintained for 8-12 minutes.

[0011] Furthermore, in step a, the mass volume ratio of the 2-chloro-N-methylacetamide to methanol is 100-300 mg:5 ml.

[0012] Furthermore, in step b, the concentration of 2-chloro-N-methylacetamide in the system suitability solution is 30-50 mg / ml, and the concentration of related substances is 50-300 μg / ml.

[0013] Furthermore, in step c, the volume ratio of cyanopropylphenyl-methylpolysiloxane in the capillary column is 6:94; the chromatographic column is preferably DB-624, 30m×0.25mm×1.4μm.

[0014] Furthermore, in step c, the temperature rising program is as follows: the initial column temperature is 80°C, maintained for 3 minutes, then increased to 180°C at 10°C per minute, and finally increased to 240°C at 20°C per minute, and maintained for 10 minutes.

[0015] Further, in step c, the chromatographic conditions include a detector: a hydrogen flame ionization detector, a detector temperature of 240 to 260°C, an injection port temperature of 190 to 210°C, a carrier gas of nitrogen, a flow rate of 1.4 to 1.6 ml / min, a split ratio of 9 to 11:1, and an injection volume of 0.8 to 1.2 μl. Preferably, the detector temperature is 250°C, the injection port temperature is 200°C, the carrier gas is nitrogen, the flow rate is 1.5 ml / min, the split ratio is 10:1, and the injection volume is 1 μl.

[0016] Furthermore, the chromatogram of the test solution presents a chromatographic peak corresponding to the retention time of the chromatographic peak of 2-chloro-N-methylacetamide in the chromatogram of the system suitability solution, that is, the test sample is 2-chloro-N-methylacetamide; and presents a chromatographic peak corresponding to the retention time of the chromatographic peak of the related substance in the chromatogram of the system suitability solution, that is, the test sample contains the corresponding related substance.

[0017] Furthermore, the content of the related substances is calculated by peak area using the main component external standard method, and the calculation formula is:

[0018] Impurity content (%) = A i ×C s ×V / A s / M / 1000×100%

[0019] Where: A i: The peak area of ​​impurities in the test solution; A s : Peak area of ​​2-chloro-N-methylacetamide in reference solution; C s : The concentration of 2-chloro-N-methylacetamide in the reference solution, μg / ml; V: The dilution volume of the test solution, ml; M: The weight of the test sample, mg;

[0020] The reference substance solution is a 2-chloro-N-methylacetamide reference substance, which is dissolved in methanol to prepare a solution with a 2-chloro-N-methylacetamide concentration of 0.1 to 0.3 mg / ml;

[0021] The peak area of ​​2-chloro-N-methylacetamide in the reference solution is the peak area of ​​the chromatographic peak of 2-chloro-N-methylacetamide in the reference chromatogram when the reference solution is injected into a gas chromatograph and detected under the same chromatographic conditions as the test solution.

[0022] Furthermore, the related substances are LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10 and / or LMS2-Z11;

[0023] The structural formula of the LMS2-Z2 is: The structural formula of the LMS2-Z4 is: The structural formula of LMS2-Z5 is: The structural formula of LMS2-Z6 is The structural formula of LMS2-Z7 is: The structural formula of LMS2-Z8 is The structural formula of LMS2-Z10 is The structural formula of LMS2-Z11 is

[0024] The detection method provided by the present invention adopts specific chromatographic conditions and can simultaneously and accurately determine and quantify eight impurities, namely LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10 and LMS2-Z11, in 2-chloro-N-methylacetamide, thereby solving the quality control problem of 2-chloro-N-methylacetamide, avoiding affecting the safety and effectiveness of chemicals and drugs using 2-chloro-N-methylacetamide as raw materials, ensuring the quality of chemicals and drugs using 2-chloro-N-methylacetamide as raw materials, and having practical application value.

[0025] Obviously, according to the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, other various forms of modification, replacement or change may be made.

[0026] The following is a further detailed description of the above contents of the present invention through specific implementation methods in the form of embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies implemented based on the above contents of the present invention belong to the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the chromatogram of the blank solution of Example 1 of the present invention;

[0028] Figure 2 is a chromatogram of the system suitability solution of Example 1 of the present invention;

[0029] Figure 3 The chromatogram of the test solution of Example 1 of the present invention;

[0030] Figure 4 This is a chromatogram of the mixed impurity solution of Comparative Example 1 of the present invention;

[0031] Figure 5 It is the chromatogram of the system suitability solution of Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0032] The raw materials and equipment used in the specific embodiments of the present invention are all known products and are obtained by purchasing commercially available products.

[0033] Example 1 Detection of Related Substances of 2-Chloro-N-Methylacetamide of the Present Invention

[0034] (1) Instrument: Shimadzu 2010Pro gas chromatograph;

[0035] (2) Chromatographic conditions:

[0036] Chromatographic column: Agilent DB-624, 30m×0.25mm×1.4μm;

[0037] The initial column temperature was 80°C, maintained for 3 minutes, increased to 180°C at 10°C / min, then increased to 240°C at 20°C / min, and maintained for 10 minutes;

[0038] Detector: Hydrogen flame ionization detector (FID), temperature is 250℃;

[0039] Inlet temperature: 200°C;

[0040] Carrier gas: high-purity nitrogen, flow rate: 1.5 ml / min, split ratio: 10:1; injection volume: 1 μl.

[0041] (3) Preparation of blank solution: Methanol was used as blank solution

[0042] (4) Preparation of reference solution:

[0043] Take about 100 mg of 2-chloro-N-methylacetamide reference substance, accurately weigh it, place it in a 50 ml volumetric flask, add methanol to dissolve and dilute to the scale, shake well; accurately measure 1 ml, place it in a 10 ml volumetric flask, dilute to the scale with methanol, and shake well.

[0044] (5) Preparation of test solution:

[0045] Take 200 mg of 2-chloro-N-methylacetamide, accurately weigh it, place it in a 5 ml volumetric flask, add methanol to dissolve and dilute to the scale, and shake well.

[0046] (6) Preparation of system suitability solution:

[0047] Take LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10, LMS2-Z11 and LMS2 reference substance, weigh accurately, dissolve in methanol and quantitatively dilute to make a mixed solution containing 40 mg of LMS2, 200 μg of LMS2-Z10, and 80 μg each of LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8 and LMS2-Z11 per 1 ml.

[0048] (7) Impurity determination:

[0049] Inject the blank solution, reference solution, system suitability solution and test solution into the gas chromatograph by direct injection, record the chromatogram, and calculate the content by peak area according to the main component external standard method.

[0050] The calculation formula is:

[0051] Impurity content (%) = A i ×C s ×V / A s / M / 1000×100%

[0052] Where: A i : Peak area of ​​impurities in the test solution;

[0053] A s : The peak area of ​​2-chloro-N-methylacetamide in the reference solution;

[0054] C s : Concentration of 2-chloro-N-methylacetamide in the reference solution, μg / ml;

[0055] V: dilution volume of the test solution, ml;

[0056] M: the weight of the test sample, mg;

[0057] (8) Test results:

[0058] The test results are shown in Figures 1 to 3 . The test results show that the blank has no interference, the peaks of each component in the system suitability solution are well separated, and the sample test results meet the standards. The specific standards are: LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8 and LMS2-Z11 shall not exceed 0.2%, LMS2-Z10 shall not exceed 0.5%, unknown impurities shall not exceed 0.1%, total impurities shall not exceed 1.0%, and chromatographic peaks less than 0.01% shall be ignored.

[0059] Comparative Example 1

[0060] (1) Instrument: Shimadzu 2010Pro gas chromatograph;

[0061] (2) Chromatographic conditions:

[0062] Chromatographic column: Agilent DB-624, 30m×0.25mm×1.4μm;

[0063] The initial column temperature was 80°C, maintained for 3 minutes, increased to 180°C at 5°C / min, then increased to 240°C at 20°C / min, and maintained for 10 minutes;

[0064] Detector: Hydrogen flame ionization detector (FID), temperature is 250℃;

[0065] Inlet temperature: 200°C;

[0066] Carrier gas: high-purity nitrogen, flow rate: 1.5 ml / min, split ratio: 10:1; injection volume: 1 μl.

[0067] (3) Preparation of mixed impurity solution:

[0068] Impurities (LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10, LMS2-Z11) and LMS2 were taken separately, dissolved in methanol and diluted to prepare a mixed solution containing 20 μg of each component per 1 ml, which was used as a mixed impurity solution.

[0069] (4) Detection:

[0070] Accurately measure 1 μl of the mixed impurity solution, inject it into the gas chromatograph, and record the chromatogram.

[0071] (5) Test results:

[0072] The test results are shown in Figure 4The test results show that the peaks of various impurities are relatively concentrated and delayed, and the response of each impurity is low, so the method is not applicable.

[0073] Comparative Example 2

[0074] (1) Instrument: Shimadzu 2010Pro gas chromatograph;

[0075] (2) Chromatographic conditions:

[0076] Chromatographic column: Agilent DB-624, 30m×0.25mm×1.4μm;

[0077] The initial column temperature was 80°C, maintained for 3 minutes, increased to 180°C at 10°C / min, then increased to 240°C at 20°C / min, and maintained for 10 minutes;

[0078] Detector: Hydrogen flame ionization detector (FID), temperature is 250℃;

[0079] Inlet temperature: 200°C;

[0080] Carrier gas: high-purity nitrogen, flow rate: 1.5 ml / min, split ratio: 5:1; injection volume: 1 μl.

[0081] (3) Preparation of system suitability solution:

[0082] Take appropriate amount of LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10, LMS2-Z11 and LMS2 reference substance, weigh accurately, dissolve in methanol and quantitatively dilute to make a mixed solution containing 20 mg of LMS2 and 20 μg each of LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z11 and LMS2-Z10 per 1 ml.

[0083] (4) Detection:

[0084] Accurately measure 1 μl of the mixed impurity solution, inject it into the gas chromatograph, and record the chromatogram.

[0085] (5) Test results:

[0086] The test results are shown in Figure 5 The experimental results show that the LMS2-Z4 peak is split and easily interfered by the solvent peak.

[0087] The beneficial effects of the present invention are further illustrated by way of test examples below:

[0088] Test Example 1 - Methodology Validation

[0089] The chromatographic conditions used in the method validation were as follows:

[0090] Gas chromatograph: Shimadzu GC-2010Pro;

[0091] Chromatographic column: Agilent DB-624, 30m×0.25mm×1.4μm;

[0092] The initial column temperature was 80°C, maintained for 3 minutes, increased to 180°C at 10°C / min, then increased to 240°C at 20°C / min, and maintained for 10 minutes;

[0093] Detector: Hydrogen flame ionization detector (FID), temperature is 250℃;

[0094] Inlet temperature: 200°C;

[0095] Carrier gas: high-purity nitrogen, flow rate: 1.5 ml / min, split ratio: 10:1; injection volume: 1 μl.

[0096] (1) Exclusivity

[0097] Blank solution: Take methanol as blank solution;

[0098] Test solution: Take 200 mg of 2-chloro-N-methylacetamide, weigh accurately, place in a 5 ml volumetric flask, add methanol to dissolve and dilute to the scale, shake well;

[0099] Take n-heptane, LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10, LMS2-Z11 and LMS2 reference substance, accurately weigh, add methanol to dissolve and quantitatively dilute to make a mixed solution containing 40 mg of LMS2, 200 μg of n-heptane and LMS2-Z10, and approximately 80 μg of LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8 and LMS2-Z11 per 1 ml.

[0100] 1 μl of system suitability solution, blank solution and test solution were measured respectively and injected into gas chromatograph for detection. The gas chromatogram results were consistent with those in Example 1. Figures 1 to 3 The blank solution and the possible residual solvent of 2-chloro-N-methylacetamide, n-heptane, did not interfere with the determination of the impurities, and the separation between the components in the system suitability solution was not less than 3.3, which was good and met the requirements.

[0101] (2) Limit of quantification

[0102] Stock solution of each impurity reference substance (5 mg / ml): Take about 50 mg of each impurity reference substance LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10, and LMS2-Z11, respectively, place them in 10 ml volumetric flasks, add diluent to dissolve and dilute to the scale, and shake well.

[0103] LMS2 reference substance stock solution (12.5 mg / ml): Take about 125 mg of LMS2 reference substance, accurately weigh it, place it in a 10 ml volumetric flask, add diluent to dissolve and dilute to the scale, and shake well.

[0104] Mixed reference substance stock solution: Accurately measure 2 ml each of LMS2, LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8 and LMS2-Z11 reference substance stock solution and 5 ml of LMS2-Z10 reference substance stock solution, place them in the same 25 ml volumetric flask, dilute to the scale with diluent, and shake well.

[0105] Quantitative limit solution: Accurately measure 0.5 ml of the mixed reference stock solution, place it in a 5 ml volumetric flask, dilute it to the scale with diluent, and shake well; then accurately measure 1 ml of the solution, place it in a 10 ml volumetric flask, dilute it to the scale with diluent, and shake well.

[0106] Detection limit solution: Accurately measure 2 ml of the mixed reference stock solution, place it in a 10 ml volumetric flask, dilute it to the scale with diluent, and shake well; accurately measure 2.5 ml of the solution, place it in a 10 ml volumetric flask, dilute it to the scale with diluent, and shake well; accurately measure 1 ml of the solution, place it in a 10 ml volumetric flask, dilute it to the scale with diluent, and shake well.

[0107] The quantitative limit solution and the detection limit solution were sampled and analyzed. The detection limit was determined at a signal-to-noise ratio of about 3, and the quantitative limit was determined at a signal-to-noise ratio of about 9. The results of the detection limit and quantitative limit of each component are shown in Table 2.

[0108] Table 2 Quantitation limit results

[0109]

[0110] The results show that the ratio of the quantitative limit solution concentration to the limit concentration of each component is no more than 5.2%, and the signal-to-noise ratio is no less than 12.7; the ratio of the detection limit solution concentration to the limit concentration of each component is no more than 2.6%, and the signal-to-noise ratio is no less than 4.9. This method has high sensitivity and meets the detection requirements.

[0111] (3) Linearity and range

[0112] Take appropriate amount of LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10, LMS2-Z11 and LMS2 reference substance respectively, weigh accurately, dilute with methanol to prepare a series of linear solutions, inject and analyze according to the above chromatographic conditions, record the chromatogram, and perform linear regression with injection concentration (μg / ml) as the abscissa (x) and peak area as the ordinate (y). The results are shown in Table 3.

[0113] Table 3 Linear relationship results

[0114]

[0115] The results showed that the main component and each impurity showed a good linear relationship within the linear range of the quantitative limit to 200%.

[0116] (4) Repeatability

[0117] Solvent: methanol.

[0118] Reference solution: Take an appropriate amount of 2-chloro-N-methylacetamide reference substance, weigh accurately, dissolve in solvent and quantitatively dilute to make a solution containing about 200 μg per 1 ml.

[0119] Test solution: Take an appropriate amount of 2-chloro-N-methylacetamide, weigh it accurately, dissolve it in solvent and quantitatively dilute it to make a solution containing about 40 mg per 1 ml, and prepare 6 copies in parallel.

[0120] Take the above solution, inject and analyze according to the above chromatographic conditions, record the chromatogram, and calculate the content of each impurity by peak area according to the main component external standard method. The results are shown in Table 4.

[0121] Table 4 Repeatability results

[0122]

[0123] The test results show that 6 test solutions were prepared in parallel. According to the main component external standard method, the average detection amount of impurity LMS2-Z10 was 0.08%, the RSD was 1.5%, and other impurities were not detected. The repeatability met the requirements.

[0124] (5) Accuracy

[0125] Diluent: methanol.

[0126] Mixed reference stock solution: Accurately measure appropriate amount of LMS2, LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10 and LMS2-Z11 reference substances, dissolve in methanol and dilute to make a mixed solution containing approximately 0.4 mg each of LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10 and LMS2-Z11 and approximately 1.0 mg of LMS2-Z10 per ml.

[0127] Test solution (baseline value): quote “Repeatability” data.

[0128] 20% recovery solution: Take about 200 mg of 2-chloro-N-methylacetamide, weigh accurately, place in a 5 ml volumetric flask, accurately add 0.2 ml of mixed reference substance stock solution, dissolve in water and dilute to scale, shake well. Prepare 3 copies in parallel.

[0129] 100% recovery solution: Take about 200 mg of 2-chloro-N-methylacetamide, weigh accurately, place in a 5 ml volumetric flask, accurately add 1 ml of mixed reference substance stock solution, dissolve in water and dilute to scale, shake well. Prepare 3 copies in parallel.

[0130] 150% recovery solution: Take about 200 mg of 2-chloro-N-methylacetamide, weigh accurately, place in a 5 ml volumetric flask, accurately add 1.5 ml of mixed reference substance stock solution, dissolve in water and dilute to scale, shake well. Prepare 3 copies in parallel.

[0131] Accurately measure 1 μl of each of the above solutions, inject them into the gas chromatograph, record the chromatogram, and calculate the recovery rate of the impurity to be tested in each recovery solution according to the impurity external standard method; the results are shown in Table 5.

[0132] Table 5 Accuracy results

[0133] name Spiking Recovery rate average % Recovery rate RSD% LMS2-Z4 0.04％～0.3％ 99.0 3.6 LMS2-Z2 0.04％～0.3％ 104.5 5.6 LMS2-Z7 0.04％～0.3％ 104.9 3.7 LMS2-Z6 0.04％～0.3％ 107.7 2.5 LMS2-Z10 0.1％～0.75％ 106.9 5.1 LMS2-Z11 0.04％～0.3％ 106.1 4.0 LMS2-Z8 0.04％～0.3％ 107.8 2.6 LMS2-Z5 0.04％～0.3％ 102.5 3.0

[0134] The test results show that within the limit concentration range of 20% to 150% for each impurity to be tested, the average recovery rate is between 99.0% and 107.8%, and the RSD value of the recovery rate is no more than 5.6%. The accuracy meets the requirements.

[0135] (6) Solution stability

[0136] Reference solution, test solution: Same as under “Repeatability”.

[0137] The reference solution and the test solution were placed at room temperature, and the system suitability solution was placed at 2-8°C. Samples were injected and analyzed at different time periods, and the chromatograms were recorded. The relative standard deviation of the peak area or content of each impurity in each solution was calculated. The test results are shown in Table 6.

[0138] Table 6 Summary of stability results of test solution (area normalization method)

[0139]

[0140] The test results show that the reference solution and the test solution are stable at room temperature for 58 hours.

[0141] (7) Durability

[0142] Dilution solution, system suitability solution, reference solution and test solution: Same as under “Repeatability”.

[0143] Fine-tune the chromatography method parameters according to Table 7, take samples of the above solutions for analysis, record the chromatograms, and calculate the content of each impurity according to the main component external standard method. The results are shown in Table 8.

[0144] Table 7 Durability chromatographic parameters

[0145]

[0146] Table 8 Durability results summary

[0147]

[0148] The test results show that after slight changes in the chromatographic parameters (starting column temperature ±5°C, column flow rate ±0.1ml / min, inlet temperature ±10°C, detector temperature ±10°C, split ratio ±1, instrument and chromatographic column), the solvent blank does not interfere with the determination of various impurities; the separation between the peaks of each component in the system suitability solution is not less than 3.2; calculated by the main component external standard method, the detection amount of impurity LMS2-Z10 in the test solution is 0.08%, and the other impurities are not detected, and the durability meets the requirements.

[0149] 2-Chloro-N-methylacetamide is the starting material of the drug Lumeperone. Based on the detection of 2-chloro-N-methylacetamide-related substances in Lumeperone, it is determined that 2-chloro-N-methylacetamide needs to meet the following standards after detection by a methodologically validated gas chromatography method: LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8 and LMS2-Z11 shall not exceed 0.2%, LMS2-Z10 shall not exceed 0.5%, unknown impurities shall not exceed 0.1%, total impurities shall not exceed 1.0%, and chromatographic peaks less than 0.01% shall be ignored. Lumeperone is synthesized using 2-chloro-N-methylacetamide that meets this standard, and the quality of the finished product Lumeperone meets the requirements.

[0150] In summary, the method for determining impurities in 2-chloro-N-methylacetamide according to the present invention has strong specificity, high sensitivity, good linearity, repeatability, accuracy, solution stability and durability.

Claims

1. A method for detecting related substances of 2-chloro-N-methylacetamide, characterized in that: It includes the following steps: a. Preparation of test solution: Take 2-chloro-N-methylacetamide to be tested and dissolve it in methanol to obtain the solution; b. Preparation of system suitability solution: Take 2-chloro-N-methylacetamide reference substance and related substance reference substance and dissolve them in methanol to obtain; c. Pipette the test solution and system suitability solution into the gas chromatograph respectively. The chromatographic conditions are as follows: Chromatographic column: capillary column with cyanopropylphenyl-methylpolysiloxane as stationary liquid, heating program: starting temperature 75-85°C, maintained for 3 minutes, then heated to 180°C at a rate of 8-10°C per minute, and finally heated to 240°C at a rate of 20-25°C per minute, maintained for 8-12 minutes.

2. The detection method according to claim 1, characterized in that: In step a, the mass volume ratio of the 2-chloro-N-methylacetamide to methanol is 100-300 mg:5 ml.

3. The detection method according to claim 1, characterized in that: In step b, the concentration of 2-chloro-N-methylacetamide in the system suitability solution is 30-50 mg / ml, and the concentration of related substances is 50-300 μg / ml.

4. The detection method according to claim 1, characterized in that: In step c, the volume ratio of cyanopropylphenyl-methylpolysiloxane in the capillary column is 6:94, and the chromatographic column is preferably DB-624, 30m×0.25mm×1.4μm.

5. The detection method according to claim 1, characterized in that: In step c, the temperature rising program is as follows: the initial column temperature is 80°C, maintained for 3 minutes, then raised to 180°C at 10°C per minute, and finally raised to 240°C at 20°C per minute, and maintained for 10 minutes.

6. The detection method according to claim 1, characterized in that: In step c, the chromatographic conditions include a flame ionization detector, a detector temperature of 240 to 260° C., an injection port temperature of 190 to 210° C., a carrier gas of nitrogen, a flow rate of 1.4 to 1.6 ml / min, a split ratio of 9 to 11:1, and an injection volume of 0.8 to 1.2 μl.

7. The detection method according to claim 6, characterized in that: The detector temperature was 250° C., the injection port temperature was 200° C., the carrier gas was nitrogen, the flow rate was 1.5 ml / min, the split ratio was 10:1, and the injection volume was 1 μl.

8. The detection method according to any one of claims 1 to 7, characterized in that: The chromatogram of the test solution presents a chromatographic peak corresponding to the retention time of the chromatographic peak of 2-chloro-N-methylacetamide in the chromatogram of the system suitability solution, that is, the test sample is 2-chloro-N-methylacetamide; and the chromatographic peak presents a chromatographic peak corresponding to the retention time of the chromatographic peak of the related substance in the chromatogram of the system suitability solution, that is, the test sample contains the corresponding related substance.

9. The detection method according to claim 8, characterized in that: The content of the related substances is calculated by peak area according to the main component external standard method, and the calculation formula is: Impurity content (%) = A i ×C s ×V / A s / M / 1000 / 100% Where: A i : The peak area of ​​impurities in the test solution; A s : Peak area of ​​2-chloro-N-methylacetamide in reference solution; C s : The concentration of 2-chloro-N-methylacetamide in the reference solution, μg / ml; V: The dilution volume of the test solution, ml; M: the weight of the test sample, mg; The reference substance solution is a 2-chloro-N-methylacetamide reference substance, which is dissolved in methanol to prepare a solution with a 2-chloro-N-methylacetamide concentration of 0.1 to 0.3 mg / ml; The peak area of ​​2-chloro-N-methylacetamide in the reference solution is the peak area of ​​the chromatographic peak of 2-chloro-N-methylacetamide in the reference chromatogram when the reference solution is injected into a gas chromatograph and detected under the same chromatographic conditions as the test solution.

10. The detection method according to claim 1, 3 or 8 to 9, characterized in that: The related substances are LMS2-Z2, LMS2-Z4, LMS2-Z5, LMS2-Z6, LMS2-Z7, LMS2-Z8, LMS2-Z10 and / or LMS2-Z11; The structural formula of the LMS2-Z2 is: The structural formula of the LMS2-Z4 is: The structural formula of LMS2-Z5 is: The structural formula of LMS2-Z6 is The structural formula of LMS2-Z7 is: The structural formula of LMS2-Z8 is The structural formula of LMS2-Z10 is The structural formula of LMS2-Z11 is

Images