A method for detecting impurities in N-(3-chloropropyl)dibutylamine

Abstract

The present invention relates to the field of drug detection technology, specifically discloses a detection method for impurities in N-(3-chloropropyl) dibutylamine. The present invention uses a DB-624 chromatographic column with a specification of 60m×0.53mm×5μm to perform gas chromatography analysis on N-(3-chloropropyl) dibutylamine samples, and realizes the accurate detection of four kinds of related substances and their contents of di-n-butylamine, 3-bromo-1-propanol, 3-dibutylamino-1-propanol and bromochloropropane present in N-(3-chloropropyl) dibutylamine at the same time. The detection method has strong specificity, low detection limit and quantitative limit, good linear relationship, high recovery rate, good repeatability, strong stability, good durability, and simple and fast operation, low detection cost, and accurate and reliable detection result, which provides a guarantee for monitoring the quality stability and clinical drug safety of N-(3-chloropropyl) dibutylamine as a doxazosin mesylate intermediate.

Description

Technical Field

[0001] The invention relates to the technical field of drug detection, and in particular to a method for detecting impurities in N-(3-chloropropyl)dibutylamine. Background Art

[0002] The molecular formula of N-(3-Chloropropyl)dibutylamine is C 11 H 24 ClN is a colorless to light yellow liquid, which is easily soluble in organic solvents and can be used as a pharmaceutical intermediate and organic solvent. In the process of synthesizing N-(3-chloropropyl)dibutylamine, di-n-butylamine, 3-bromo-1-propanol, 3-dibutylamino-1-propanol, bromochloropropane and other related substances will inevitably appear. When N-(3-chloropropyl)dibutylamine is used as the starting material of dronedarone hydrochloride, its purity directly affects the quality of its finished product. Therefore, it is necessary to strictly control the content of related impurities in N-(3-chloropropyl)dibutylamine.

[0003] There is no report on the detection method of related substances (di-n-butylamine, 3-bromo-1-propanol, 3-dibutylamino-1-propanol, bromochloropropane) in N-(3-chloropropyl) dibutylamine. In order to accurately detect the above-mentioned related substances, multiple detections are required, and the operation process is cumbersome, time-consuming and laborious. Therefore, the present invention needs to provide a detection method that can accurately detect related substances in N-(3-chloropropyl) dibutylamine. Summary of the invention

[0004] In view of the above problems, the present invention provides a method for detecting impurities in N-(3-chloropropyl)dibutylamine. The impurities di-n-butylamine, 3-bromo-1-propanol, 3-dibutylamino-1-propanol and bromochloropropane in N-(3-chloropropyl)dibutylamine can be accurately detected simultaneously by gas chromatography.

[0005] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0006] A method for detecting impurities in N-(3-chloropropyl)dibutylamine comprises the following steps:

[0007] Preparation of test solution: Dissolve N-(3-chloropropyl)dibutylamine sample in solvent to obtain test solution;

[0008] Preparation of reference solution: dissolve di-n-butylamine reference, 3-bromo-1-propanol reference, 3-dibutylamino-1-propanol reference and bromochloropropane reference in a solvent to obtain a reference solution;

[0009] The reference solution and the test solution are detected by gas chromatography, and the chromatographic conditions of the gas chromatography include:

[0010] A DB-624 chromatographic column was used, with specifications of 60m×0.53mm and a filler diameter of 5μm;

[0011] The heating program is as follows: starting temperature 48-52°C, maintaining for 4-6 min, heating to 220-240°C at a rate of 18-22°C / min, maintaining for 10-20 min;

[0012] The injection port temperature is 240-260°C;

[0013] The detector temperature is 270-290°C.

[0014] Compared with the prior art, the method for detecting impurities in N-(3-chloropropyl)dibutylamine provided by the present invention adopts a DB-624 chromatographic column with a specification of 60m×0.53mm×5μm to perform gas chromatography analysis on the N-(3-chloropropyl)dibutylamine sample, thereby realizing accurate detection of four related substances and their contents, namely, di-n-butylamine, 3-bromo-1-propanol, 3-dibutylamino-1-propanol and bromochloropropane, present in N-(3-chloropropyl)dibutylamine. The present invention improves the peak response intensity of the test solution and the reference solution by limiting the temperature rise program of the gas chromatograph and the temperature of the injection port and the detector, thereby improving the detection accuracy. The detection method has strong specificity, low detection limit and quantification limit, good linear relationship, high recovery rate, good repeatability, strong stability, good durability, simple and quick operation, low detection cost, accurate and reliable test results, and can provide data support for the effective control of the quality of N-(3-chloropropyl) dibutylamine in the production process, and provides a guarantee for monitoring the quality stability and clinical drug safety of N-(3-chloropropyl) dibutylamine as an intermediate of dronedarone hydrochloride.

[0015] Preferably, the solvent is methanol.

[0016] Preferably, the concentration of the test solution is 18-22 mg / mL.

[0017] Preferably, the concentration of di-n-butylamine in the reference solution is 60-120 μg / mL.

[0018] Preferably, the concentration of 3-bromo-1-propanol in the reference solution is 60-120 μg / mL.

[0019] Preferably, the concentration of 3-dibutylamino-1-propanol in the reference solution is 60-120 μg / mL.

[0020] Preferably, the concentration of bromochloropropane in the reference solution is 60-120 μg / mL.

[0021] Preferably, the chromatographic conditions of the gas chromatography also include:

[0022] The detector is a hydrogen flame ionization detector;

[0023] The carrier gas was nitrogen with a flow rate of 4.5 to 5.5 mL / min;

[0024] The injection volume is 0.8-1.2 μL;

[0025] The split ratio is (5~15):1.

[0026] For example, the stationary liquid of the DB-624 chromatographic column is 6% cyanopropylphenyl-94% dimethylpolysiloxane. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0028] Figure 2 is the gas chromatogram of the reference substance solution in Example 1 of the present invention;

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

[0030] Figure 4 The gas chromatogram of the spiked test solution in Example 1 of the present invention;

[0031] Figure 5 The gas chromatogram of the reference substance solution in Comparative Example 2 of the present invention;

[0032] Figure 6 The gas chromatogram of the spiked test solution in Comparative Example 2 of the present invention;

[0033] Among them, chromatographic peak 1 is bromochloropropane, chromatographic peak 2 is di-n-butylamine, chromatographic peak 3 is 3-bromo-1-propanol, chromatographic peak 4 is 3-dibutylamino-1-propanol, and chromatographic peak 5 is N-(3-chloropropyl)dibutylamine. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] Example 1

[0036] This embodiment provides a method for detecting impurities in N-(3-chloropropyl)dibutylamine, comprising the following steps:

[0037] (1) Solution preparation

[0038] Blank solution: methanol.

[0039] Reference substance stock solution: Take appropriate amounts of di-n-butylamine reference substance, 3-bromo-1-propanol reference substance, 3-dibutylamino-1-propanol reference substance and bromochloropropane reference substance, weigh them accurately, dilute and dissolve them quantitatively with methanol, and make a mixed solution containing 1000 μg of each in 1 mL to obtain the reference substance stock solution. That is, in the reference substance stock solution, the concentrations of di-n-butylamine, 3-bromo-1-propanol, 3-dibutylamino-1-propanol and bromochloropropane are all 1000 μg / mL.

[0040] Reference solution: Accurately pipette an appropriate amount of reference stock solution, quantitatively dilute with methanol, and prepare a mixed solution containing 100 μg of each in 1 mL to obtain the reference solution. That is, in the reference solution, the concentrations of di-n-butylamine, 3-bromo-1-propanol, 3-dibutylamino-1-propanol, and bromochloropropane are all 100 μg / mL.

[0041] Test solution: Take 200 mg of N-(3-chloropropyl)dibutylamine sample, accurately weigh it, place it in a 10 mL volumetric flask, add methanol to dissolve and dilute to the scale to obtain the test solution.

[0042] Spiked test solution: Take 200 mg of N-(3-chloropropyl)dibutylamine sample, accurately weigh it, place it in a 10 mL volumetric flask, accurately add 1 mL of the above-mentioned reference substance stock solution, dissolve it with methanol and make up to the scale to obtain the spiked test solution.

[0043] (2) The blank solution, reference solution, test solution and spiked test solution are tested by gas chromatography. The specific chromatographic conditions of the gas chromatography include:

[0044] A DB-624 chromatographic column (60 m × 0.53 mm, 5 μm) was used;

[0045] The temperature program of the gas chromatography was as follows: starting temperature 50 °C, maintained for 5 min, increasing to 230 °C at a rate of 20 °C / min, maintained for 15 min;

[0046] The detector was a hydrogen flame ionization (FID) detector with an inlet temperature of 250°C and a detector temperature of 280°C;

[0047] The carrier gas was nitrogen with a flow rate of 5 mL / min;

[0048] The injection volume was 1 μL;

[0049] The split ratio is 10:1.

[0050] The gas chromatogram results of blank solution, reference solution, test solution and spiked test solution are as follows Figures 1 to 4 As shown, the separation degree of each impurity in the reference solution was tested, and the test results are shown in Table 1. Figures 1 to 4 As can be seen from Table 1, in the method for detecting impurities in N-(3-chloropropyl)dibutylamine provided in this embodiment, the blank solvent does not interfere with the detection of each component, the separation degree between the components meets the requirements, and the method has good specificity.

[0051] Table 1 Retention time and separation of each impurity in the reference solution

[0052] Element Retention time min Separation Methanol 4.29 - Bromochloropropane 12.303 75.802 Dibutylamine 12.768 6.579 3-Bromo-1-propanol 12.942 2.524 3-Dibutylamino-1-propanol 17.097 42.302

[0053] Methodological validation

[0054] Durability test

[0055] The reference solution was prepared according to the method of Example 1, and only the starting temperature, heating rate, injection port temperature and detector temperature were changed respectively, and the single factor variables were controlled. The detection was carried out according to the detection method of Example 1, and the detection results are shown in Tables 2 to 5. It can be seen from Tables 2 to 5 that the separation degree of each impurity meets the requirements when each condition is changed, indicating that the detection method of impurities in N-(3-chloropropyl)dibutylamine provided by the present invention has good durability.

[0056] Table 2 Separation of impurities in reference solution at different starting temperatures

[0057]

[0058]

[0059] Table 3 Separation of impurities in reference solution at different heating rates

[0060] Heating rate 20℃ / min 18℃ / min 22℃ / min Bromochloropropane 75.819 77.115 74.503 Dibutylamine 6.58 6.755 6.34 3-Bromo-1-propanol 2.543 2.564 2.511 3-Dibutylamino-1-propanol 42.099 42.816 41.4

[0061] Table 4 Separation of impurities in reference solution at different injection port temperatures

[0062] Inlet temperature 250℃ 240℃ 260℃ Bromochloropropane 75.819 75.67 75.551 Dibutylamine 6.58 6.57 6.578 3-Bromo-1-propanol 2.543 2.542 2.545 3-Dibutylamino-1-propanol 42.099 41.966 42.004

[0063] Table 5 Separation of impurities in reference solution at different detector temperatures

[0064] Detector temperature 280℃ 270℃ 290℃ Bromochloropropane 75.819 75.741 75.628 Dibutylamine 6.58 6.572 6.565 3-Bromo-1-propanol 2.543 2.542 2.545 3-Dibutylamino-1-propanol 42.099 41.923 42.074

[0065] Limit of detection and limit of quantitation test

[0066] Accurately weigh appropriate amounts of di-n-butylamine reference substance, 3-bromo-1-propanol reference substance, 3-dibutylamino-1-propanol reference substance, bromochloropropane reference substance and N-(3-chloropropyl) dibutylamine reference substance, prepare sample solutions with a concentration of 100 μg / mL respectively, and detect according to the chromatographic conditions in Example 1, record the gas chromatogram, and the peak height is 10 times the baseline noise as the quantitative limit, and the peak height is 3 times the baseline noise as the detection limit. The test results of the quantitative limit and the detection limit are shown in Table 6, and the repeatability test results of the quantitative limit are shown in Table 7. It can be seen from Tables 6 to 7 that the detection limit and the quantitative limit of the detection method provided by the present invention for detecting impurities in N-(3-chloropropyl) dibutylamine are low, and the detection of impurities in N-(3-chloropropyl) dibutylamine has the characteristics of high sensitivity; the relative standard deviation (RSD) of the peak area of ​​each impurity repeated 6 times is 3.35% at most, indicating that the detection method provided by the present invention has good repeatability of the quantitative limit.

[0067] Table 6 Test results of limit of quantitation and limit of detection

[0068]

[0069]

[0070] Table 7 Results of quantitation limit repeatability test

[0071] Element 1 2 3 4 5 6 RSD% Bromochloropropane 3080 3107 3101 3028 3100 3110 1.01 Dibutylamine 3492 3477 3490 3446 3500 3528 0.77 3-Bromo-1-propanol 3439 3459 3425 3466 3416 3447 0.56 3-Dibutylamino-1-propanol 4142 4116 4112 4029 3985 4382 3.35 N-(3-Chloropropyl)dibutylamine 5554 5642 5516 5460 5339 5541 1.85

[0072] Linear relationship test

[0073] Accurately weigh appropriate amounts of di-n-butylamine reference substance, 3-bromo-1-propanol reference substance, 3-dibutylamino-1-propanol reference substance, bromochloropropane reference substance and N-(3-chloropropyl) dibutylamine reference substance, prepare sample solutions of 10 concentration levels respectively, detect the sample solutions according to the chromatographic conditions in Example 1, measure the peak area of ​​the gas chromatogram, plot the standard working curve and establish a linear equation with the component concentration in the sample solution as the abscissa and the peak area as the ordinate, and the final test results are shown in Tables 8 to 12. It can be seen from the data in Tables 8 to 12 that in the detection method provided by the present invention, the concentration of N-(3-chloropropyl) dibutylamine and its impurities has a good linear relationship with the peak area measured by gas chromatography.

[0074] Table 8 Linear relationship test results of di-n-butylamine

[0075]

[0076] Table 9 Linear relationship test results of 3-bromo-1-propanol

[0077]

[0078] Table 10 Linear relationship test results of 3-dibutylamino-1-propanol

[0079]

[0080] Table 11 Linear relationship test results of bromochloropropane

[0081]

[0082] Table 12 Linear relationship test results of N-(3-chloropropyl)dibutylamine

[0083]

[0084] Recovery test

[0085] Prepare the reference stock solution according to the method of Example 1. Take 200 mg of N-(3-chloropropyl)dibutylamine sample, accurately weigh it, place it in a 10 mL volumetric flask, add an appropriate amount of methanol to dissolve it, and prepare 9 copies in parallel; then add the reference stock solution respectively to make the concentration of each impurity at three levels of low, medium and high, and prepare 3 copies in parallel; use methanol to make the volume to the scale, shake well, and use it as the recovery test solution. Detection was carried out according to the detection method and chromatographic conditions in Example 1. The recovery rates of each impurity in the N-(3-chloropropyl)dibutylamine sample were finally measured as shown in Tables 13 to 16. It can be seen from Tables 13 to 16 that the recovery rates of each impurity at three different addition amounts were between 89% and 106%, and the maximum RSD was 7.03%, indicating that the detection method provided by the present invention has good accuracy.

[0086] Table 13 Recovery of di-n-butylamine

[0087]

[0088]

[0089] Table 14 Recovery of 3-bromo-1-propanol

[0090]

[0091] Table 15 Recovery of 3-dibutylamino-1-propanol

[0092]

[0093] Table 16 Recovery of bromochloropropane

[0094]

[0095] Repeatability test

[0096] Six groups of N-(3-chloropropyl)dibutylamine samples from the same batch were taken, and the test solutions were prepared according to the method in Example 1, and the samples were injected according to the chromatographic conditions in Example 1, and the contents of various impurities in different groups of N-(3-chloropropyl)dibutylamine samples were detected respectively. The test results are shown in Table 17. As can be seen from Table 17, the detection results of the detection method provided by the present invention for repeated detection of impurities in the same batch of N-(3-chloropropyl)dibutylamine samples are basically consistent, and have good repeatability.

[0097] Table 17 Repeatability test results of each impurity content (%)

[0098]

[0099]

[0100] Solution stability test

[0101] The reference solution and the test solution were prepared according to the method in Example 1, and after being placed at room temperature for 0 h, 2 h, 4 h, 8 h, 15 h and 26 h, gas chromatography was performed under the chromatographic conditions in Example 1. The stability test results of the solution are shown in Tables 18 to 19. As can be seen from Tables 18 to 19, the same method was used for testing within 26 h at room temperature, and the results obtained were basically the same - the relative standard deviation (RSD) of the peak area of ​​each impurity of the reference solution was less than 2%, and the relative standard deviation (RSD) of the peak area of ​​each impurity of the test solution was less than 8%, and there was no significant difference in the test results, indicating that the reference solution and the test solution prepared by the present invention have good stability.

[0102] Table 18 Stability of reference solution (peak area)

[0103]

[0104] Table 19 Stability of test solution (peak area)

[0105]

[0106]

[0107] Comparative Example 1

[0108] This comparative example provides a method for detecting impurities in N-(3-chloropropyl)dibutylamine, which is similar to Example 1, except that the chromatographic column is replaced with an HP-5 chromatographic column (30m×0.53mm, 3μm; the stationary liquid is 5% phenyl-95% dimethylpolysiloxane), and the other conditions are the same as those in Example 1 and will not be repeated.

[0109] In this comparative example, the peak response of the test solution was significantly reduced, and the peak response values ​​of the main component and each impurity were significantly reduced.

[0110] Comparative Example 2

[0111] This comparative example provides a method for detecting impurities in N-(3-chloropropyl)dibutylamine, which is similar to Example 1, except that: ① the temperature rise program of the gas chromatography is: starting temperature 50°C, maintained for 5 min, heated to 150°C at a rate of 20°C / min, and maintained for 15 min; ② the injection port temperature is 140°C and the detector temperature is 250°C; other conditions are the same as those in Example 1 and will not be repeated.

[0112] The gas chromatogram of this comparative example is as follows Figures 5-6 As shown, the peak of di-n-butylamine is tailing, the response is significantly reduced, and the detection accuracy cannot reach the level of Example 1.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting impurities in N-(3-chloropropyl)dibutylamine, characterized in that: The following steps are involved: Preparation of test solution: Dissolve N-(3-chloropropyl)dibutylamine sample in solvent to obtain test solution; Preparation of reference solution: dissolve di-n-butylamine reference, 3-bromo-1-propanol reference, 3-dibutylamino-1-propanol reference and bromochloropropane reference in a solvent to obtain a reference solution; The reference solution and the test solution are detected by gas chromatography, and the chromatographic conditions of the gas chromatography include: A DB-624 chromatographic column was used, with specifications of 60m×0.53mm and a filler diameter of 5μm; The heating program is as follows: starting temperature 48-52°C, maintaining for 4-6 min, heating to 220-240°C at a rate of 18-22°C / min, maintaining for 10-20 min; The injection port temperature is 240-260°C; The detector temperature is 270-290°C.

2. The method for detecting impurities in N-(3-chloropropyl)dibutylamine according to claim 1, characterized in that: The solvent is methanol.

3. The method for detecting impurities in N-(3-chloropropyl)dibutylamine according to claim 1, characterized in that: The concentration of the test solution is 18-22 mg / mL.

4. The method for detecting impurities in N-(3-chloropropyl)dibutylamine according to claim 1, characterized in that: The concentration of di-n-butylamine in the reference solution is 60-120 μg / mL; and / or The concentration of 3-bromo-1-propanol in the reference solution is 60-120 μg / mL.

5. The method for detecting impurities in N-(3-chloropropyl)dibutylamine according to claim 1, characterized in that: The concentration of 3-dibutylamino-1-propanol in the reference solution is 60-120 μg / mL; and / or The concentration of bromochloropropane in the reference solution is 60-120 μg / mL.

6. The method for detecting impurities in N-(3-chloropropyl)dibutylamine according to claim 1, characterized in that: The chromatographic conditions of the gas chromatography also include: the detector is a hydrogen flame ionization detector.

7. The method for detecting impurities in N-(3-chloropropyl)dibutylamine according to claim 1, characterized in that: The chromatographic conditions of the gas chromatography method also include: the carrier gas is nitrogen.

8. The method for detecting impurities in N-(3-chloropropyl)dibutylamine according to claim 7, characterized in that: The flow rate of the nitrogen gas is 4.5-5.5 mL / min.

9. The method for detecting impurities in N-(3-chloropropyl)dibutylamine according to claim 1, characterized in that: The chromatographic conditions of the gas chromatography method also include: the injection volume is 0.8-1.2 μL.

10. The method for detecting impurities in N-(3-chloropropyl)dibutylamine according to claim 1, characterized in that: The chromatographic conditions of the gas chromatography method also include: the split ratio is (5-15):1.

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