A method for separating and detecting impurities in labetalol hydrochloride injection

Abstract

The application relates to the technical field of medical detection, and particularly discloses a separation and detection method of impurities in labetalol hydrochloride injection, which adopts an HPLC method, uses propylsilane bonded silica gel as a filler, adopts mobile phase A and mobile phase B for gradient elution, and enters a detector for detection; the mobile phase A is a perchlorate buffer solution, and the mobile phase B is a tetrahydrofuran solution containing trifluoroacetic acid; the impurities include at least one of impurity A, impurity B, impurity C, impurity D, impurity F and impurity G. The detection method has strong specificity, high sensitivity, high separation degree of main peaks and impurities, good accuracy, and convenient operation, and can effectively control the quality of the medicine.

Description

Technical Field

[0001] The invention belongs to the technical field of medical detection, and particularly relates to a method for separating and detecting impurities in labetalol hydrochloride injection. Background Art

[0002] Labetalol hydrochloride, chemically known as 5-[1-hydroxy-2-(1-methyl-3-phenylpropylamino)-ethyl] salicylamide hydrochloride, is an antihypertensive drug with both α- and β-receptor blocking effects. It is mainly used to treat various types of hypertension. Its structural formula is shown below:

[0003]

[0004] Labetalol hydrochloride injection is used for various types of hypertensive emergencies, such as hypertensive crisis, pheochromocytoma crisis, preeclampsia, hypertensive encephalopathy, hypertension caused by extensive burns, hypertension associated with coronary artery disease or acute myocardial infarction, and postoperative hypertension. It can also be used to control blood pressure during anesthesia. Labetalol hydrochloride injection is an effective drug for the clinical treatment of hypertension. However, the labetalol hydrochloride molecule contains phenolic hydroxyl and amide structures, which are susceptible to oxidation and hydrolysis. Degradation products may also be generated during production and storage. As an important drug for the treatment of pregnancy-induced hypertension, it has more stringent safety requirements, making the determination of related substances essential. Improving the impurity research of labetalol hydrochloride injection will help strictly control product quality and has important practical significance in clinical practice.

[0005] Based on Chinese and foreign literature and national pharmacopoeia standards, the impurities that need to be studied in labetalol hydrochloride injection are: Impurity A, Impurity B, Impurity C, Impurity D, Impurity F, and Impurity G. The structural formulas are as follows:

[0006]

[0007] Weng Ling et al. studied the effect of changes in the sterilization process of labetalol hydrochloride injection on impurities (Weng Ling, Zhang Xiaoyan, Liang Jie. Investigation of impurities in labetalol hydrochloride injection after changes in the sterilization process [J]. Journal of Shenyang Pharmaceutical University, 2014, 31(11): 896-904.) and established an HPLC analysis method for impurity A and other related substances and 5-HMF in labetalol hydrochloride injection. The method was validated and found to be highly specific and accurate.

[0008] However, the prior art does not provide a method for the simultaneous separation and detection of impurities A, B, C, D, F, and G from labetalol hydrochloride. To effectively improve drug safety, it is necessary to study impurities A, B, C, D, F, and G in conjunction with the labetalol hydrochloride synthesis route and degradation products. Therefore, a high-performance liquid chromatography method with high sensitivity and specificity was developed to achieve effective separation and accurate quantification of each impurity, which would be of great benefit to effectively controlling the quality of labetalol hydrochloride injection. Summary of the Invention

[0009] As used herein, the singular forms "a," "an," and "the" include both singular and plural referents unless the context clearly dictates otherwise. Numerical ranges recited by endpoints include all numbers and fractions within the corresponding ranges, as well as the recited endpoints.

[0010] In response to the problems existing in the prior art, the present invention provides a method for separating and detecting impurities in labetalol hydrochloride injection. The detection method has strong specificity, high sensitivity, good accuracy, and is easy to operate, and can effectively control the quality of the drug.

[0011] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0012] The present invention provides a method for separating and detecting impurities in labetalol hydrochloride injection, wherein the separation and detection method adopts an HPLC method; the chromatographic conditions of the HPLC method are:

[0013] Chromatographic column: Propylsilane bonded silica gel as filler;

[0014] Mobile phase: Mobile phase A is perchlorate buffer solution, and mobile phase B is tetrahydrofuran solution containing trifluoroacetic acid;

[0015] Elution: Gradient elution, the elution program is as follows:

[0016] 0-5 minutes, mobile phase A dosage is 60-85%, mobile phase B dosage is 15-40%;

[0017] 5-15 minutes, mobile phase A dosage is 30-65%, mobile phase B dosage is 35-70%;

[0018] 15-45 minutes, mobile phase A dosage is 25-45%, mobile phase B dosage is 55-75%;

[0019] 45-55 minutes, the amount of mobile phase A is 60-85%, and the amount of mobile phase B is 15-40%.

[0020] Preferably, the impurities include at least one of impurity A, impurity B, impurity C, impurity D, impurity F and impurity G.

[0021] Preferably, the mobile phase A is a perchlorate buffer solution, the concentration of the perchlorate buffer solution is 10-50 mmol / L, and the pH of the perchlorate buffer solution is 3.5-5.5; the mobile phase B is a tetrahydrofuran solution containing trifluoroacetic acid.

[0022] Preferably, the mobile phase A is selected from any one or more of potassium perchlorate buffer solution, sodium perchlorate buffer solution, and ammonium perchlorate buffer solution; and the mobile phase B is a tetrahydrofuran solution containing 0.05%-0.2% trifluoroacetic acid.

[0023] Preferably, the mobile phase A is a sodium perchlorate buffer solution having a concentration of 10-50 mmol / L and a pH of 3.5-5.5; the mobile phase B is a tetrahydrofuran solution containing 0.1% trifluoroacetic acid, v / v.

[0024] Further preferably, the mobile phase A is a sodium perchlorate buffer solution, the concentration of the sodium perchlorate buffer solution is 30 mmol / L, and the pH of the sodium perchlorate buffer solution is 5.0; the mobile phase B is a tetrahydrofuran solution containing 0.1% trifluoroacetic acid, v / v.

[0025] Preferably, the flow rate of the mobile phase is 0.5-1.5 ml / min.

[0026] Further preferably, the flow rate of the mobile phase is 1.2 ml / min.

[0027] Preferably, in the HPLC method, the injection volume is 5-50 μl, the detection wavelength of the detector is 220-265 nm, and the column temperature of the chromatographic column is 25-45° C.

[0028] Further preferably, in the HPLC method, the injection volume is 20 μl, the detection wavelength of the detector is 230 nm, and the column temperature of the chromatographic column is 30° C.

[0029] Preferably, the separation and detection method comprises the following steps:

[0030] (1) Sample preparation: Dissolve the reference substance and test substance in a diluent to prepare reference substance solution and test substance solution respectively;

[0031] (2) Using the chromatographic conditions of the HPLC method, the reference solution and the test solution were analyzed by high performance liquid chromatography.

[0032] Preferably, the diluent is an aqueous phosphoric acid solution.

[0033] Preferably, the elution procedure is as follows:

[0034] 0 min, mobile phase A was 75%, mobile phase B was 25%;

[0035] 5 minutes, mobile phase A is 55%, mobile phase B is 45%;

[0036] 15 minutes, mobile phase A is 35%, mobile phase B is 65%;

[0037] 45 minutes, mobile phase A is 30%, mobile phase B is 70%;

[0038] 55 minutes, mobile phase A is 75%, mobile phase B is 25%.

[0039] The present invention also provides an application of the above separation and detection method in quality detection of labetalol hydrochloride injection.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The HPLC method provided by the present invention can effectively separate and determine the contents of impurities A, B, C, D, F, and G in labetalol hydrochloride injection, and has high sensitivity and strong specificity. The test results are reliable and accurate, providing a technical means for the detection of impurities in labetalol hydrochloride injection, thereby performing quality control thereof.

[0042] (2) The present invention screened the chromatographic conditions to achieve a separation greater than 1.5 between impurities A, B, C, D, F, and G, as well as between impurities and the main component. This method was compared with the reference literature on labetalol hydrochloride injection published so far and was confirmed to be a new method.

[0043] (3) The new detection method discovered by the present invention can provide a reference standard for the quality control of labetalol hydrochloride injection and the safety detection of clinical safe drug use, thereby ensuring the safety and reliability of clinical drug use. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The specificity-blank solution chromatogram is shown in FIG.

[0045] Figure 2 The figure is an enlarged view of the chromatogram of the specificity-test solution; among them, 1 is impurity C, 2 is labetalol hydrochloride, and 3 is impurity A.

[0046] Figure 3 The original chromatogram of the specificity-test solution is shown in Figure 1; 1 is impurity C, 2 is labetalol hydrochloride, and 3 is impurity A.

[0047] Figure 4The figure is a chromatogram of the specificity-system suitability solution; among them, 1 is impurity D, 2 is impurity C, 3 is labetalol hydrochloride, 4 is impurity F, 5 is impurity A, 6 is impurity G, and 7 is impurity B.

[0048] Figure 5 This is the linear standard curve of impurity A.

[0049] Figure 6 This is the linear standard curve of impurity B.

[0050] Figure 7 This is the linear standard curve of impurity C.

[0051] Figure 8 This is the linear standard curve of impurity D.

[0052] Figure 9 This is the linear standard curve of impurity F.

[0053] Figure 10 This is the linear standard curve of impurity G.

[0054] Figure 11 Linear standard curve of labetalol hydrochloride. DETAILED DESCRIPTION

[0055] The present invention is described below through specific embodiments to make the technical solution of the present invention easier to understand and grasp, but the present invention is not limited thereto. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0056] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0057] Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without inventive effort shall fall within the scope of protection of the present invention. The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0058] The reagent information used in the specific implementation process of the present invention is as follows:

[0059] (1) Labetalol hydrochloride injection was obtained from Zhejiang Hemukang Pharmaceutical Technology Co., Ltd., batch number: Z-LAB2206015; specification: 20 ml: 100 mg;

[0060] (2) The source information of the reference substance is as follows:

[0061] Labetalol hydrochloride reference substance: China Institute for Drug Control; batch number: 100484-201001; content: 99.8%;

[0062] Impurity A reference substance: SINCO; batch number: 20-08-2511; content: 99.39%;

[0063] Impurity B reference substance: SINCO; batch number: 22-03-3007; content: 97.67%;

[0064] Impurity C reference substance: SINCO; batch number: 21-06-2323; content: 98.78%;

[0065] Impurity D reference substance: SINCO; batch number: 22-02-2419; content: 97.19%;

[0066] Impurity F reference substance: SINCO; batch number: 20-08-0621; content: 91.99%;

[0067] Impurity G reference substance: SINCO; batch number: 22-03-3008; content: 98.47%.

[0068] Example 1 Impurity detection

[0069] (1) Chromatographic conditions:

[0070] Instrument: Thermo Vanquish;

[0071] Chromatographic column: propylsilane bonded silica gel as filler (ZORBAX 300SB-C3, 4.6 mm x 150 mm, 3.5 μm);

[0072] Mobile phase A: 30 mmol / L perchlorate solution, adjust pH to 5.0 with perchloric acid (accurately weigh a certain amount of sodium perchlorate, dissolve in water to prepare a 30 mmol / L solution, adjust pH to 5.0 with perchloric acid, filter, and ultrasonic degassing); mobile phase B: 0.1% trifluoroacetic acid in tetrahydrofuran.

[0073] Detector: UV; detection wavelength: 230 nm; flow rate: 1.2 ml / min; column temperature: 35°C; injection volume: 20 μl. The linear elution gradient is as follows.

[0074] Table 1 Elution gradient

[0075] Time (minutes) Mobile phase A (%) Mobile phase B (%) 0 75 25 5 55 45 15 35 65 45 30 70 55 75 25

[0076] The method was methodologically validated, and the validation items included specificity, limit of quantification, limit of detection, linearity, and robustness, as follows:

[0077] (2) Methodological validation - specificity

[0078] Diluent: 0.1% aqueous phosphoric acid solution.

[0079] Labetalol hydrochloride stock solution: 5.112 mg of labetalol hydrochloride reference substance was accurately weighed into a 100-ml volumetric flask, dissolved and diluted to the mark with diluent, and shaken to obtain the stock solution.

[0080] Impurity stock solution: 1.005 mg of impurity A reference substance, 0.996 mg of impurity B reference substance, 0.957 mg of impurity C reference substance, 1.086 mg of impurity D reference substance, 1.157 mg of impurity F reference substance, and 1.095 mg of impurity G reference substance were accurately weighed into a 20-ml volumetric flask, dissolved and diluted to the mark with diluent, and shaken to obtain the stock solution.

[0081] Reference solution: 5 ml of the main component stock solution was accurately transferred into a 50-ml volumetric flask, diluted to the mark with diluent, and shaken to obtain the reference solution.

[0082] Test solution: 5 ml of the product was accurately measured into a 10-ml volumetric flask, diluted to the mark with diluent, and shaken to obtain the test solution.

[0083] Impurity A positioning solution: 1.102 mg of impurity A reference substance was accurately weighed into a 20-ml volumetric flask, dissolved and diluted to the mark with diluent, and shaken to obtain the positioning solution.

[0084] Impurity B positioning solution: 1.114 mg of impurity B reference substance was accurately weighed into a 20-ml volumetric flask, dissolved and diluted to the mark with diluent, and shaken to obtain the positioning solution.

[0085] Impurity C positioning solution: 0.987 mg of impurity C reference substance was accurately weighed into a 20-ml volumetric flask, dissolved and diluted to the mark with diluent, and shaken to obtain the positioning solution.

[0086] Impurity D positioning solution: 1.095 mg of impurity D reference substance was accurately weighed into a 20-ml volumetric flask, dissolved and diluted to the mark with diluent, and shaken to obtain the positioning solution.

[0087] Impurity F positioning solution: 1.007 mg of impurity F reference substance was accurately weighed into a 20-ml volumetric flask, dissolved and diluted to the mark with diluent, and shaken to obtain the positioning solution.

[0088] Impurity G positioning solution: 1.090 mg of impurity G reference substance was accurately weighed into a 20-ml volumetric flask, dissolved and diluted to the mark with diluent, and shaken to obtain the positioning solution.

[0089] Specific solution: Accurately measure 5 ml of this product, place it in a 10 ml volumetric flask, add 1 ml of impurity stock solution, dilute to the scale with diluent, shake well, and obtain.

[0090] According to the above chromatographic conditions, accurately measure 20 μl of blank solution (diluent), reference solution, test solution, each impurity location solution and specific solution, inject them into the liquid chromatograph, and record the chromatogram. The specificity results are shown in the table below and the chromatogram of the specific solution is shown in Figures 1-4 .

[0091] Table 2 Specificity results

[0092]

[0093] The results show that the separation degree between each impurity and the preceding and following impurities in the specific solution is greater than 1.5, the separation degree is good, and the separation and detection method provided by the present invention has good specificity.

[0094] (3) Methodological validation - limit of quantification

[0095] Labetalol hydrochloride stock solution: Prepare the same as described under “(2) Specificity”.

[0096] Impurity stock solution: Prepare the same as under “(2) Specificity”.

[0097] Quantitation limit stock solution: Accurately measure 1 ml of impurity stock solution and 1 ml of main component stock solution, place them in a 10 ml volumetric flask, dilute to the scale with diluent, shake well, and obtain.

[0098] Quantitation limit solution: Accurately measure 1 ml of the quantitation limit stock solution, place it in a 10 ml volumetric flask, dilute to the scale with diluent, shake well, and the solution is obtained (prepare 6 copies in parallel).

[0099] According to the above chromatographic conditions, accurately measure 20 μl and inject it into the liquid chromatograph. Record the chromatogram and calculate the RSD% of the peak area of ​​6 portions of labetalol hydrochloride and impurities. The quantitative limit results are shown in Tables 3 to 9.

[0100] Table 3 Quantitation limit test (impurity A)

[0101]

[0102] Table 4 Quantitation limit test (impurity B)

[0103]

[0104] Table 5 Quantitation limit test (impurity C)

[0105]

[0106] Table 6 Quantitation limit test (impurity D)

[0107]

[0108] Table 7 Quantitation limit test (impurity F)

[0109]

[0110]

[0111] Table 8 Quantitation limit test (impurity G)

[0112]

[0113] Table 9 Limit of Quantitation Test (Labetalol Hydrochloride)

[0114]

[0115] The results showed that the signal-to-noise ratios of all peaks in the six quantification limit solutions were greater than 10, and the relative standard deviations (RSDs) of the peak areas of each impurity peak were less than 10%. At a sample concentration of 2.5 mg / ml, impurities A, B, C, D, F, G, and other impurities could be accurately quantified when their concentrations exceeded 0.02% of the sample concentration.

[0116] (4) Methodological validation - detection limit

[0117] Quantitation limit solution: Prepare the same as in “(3) Quantitation limit”.

[0118] Detection limit solution: Accurately pipette 1 ml of the quantitative limit solution into a 5 ml volumetric flask, dilute to the scale with diluent, and shake well.

[0119] Take the above solution, accurately measure 20 μl according to the above chromatographic conditions, inject it into the liquid chromatograph, record the chromatogram, and the detection limit results are shown in the table below.

[0120] Table 10 Detection limit test

[0121]

[0122] The results showed that the signal-to-noise ratios of impurity A, impurity B, impurity C, impurity D, impurity F, impurity G, and labetalol hydrochloride were 4.6, 9.9, 4.5, 7.4, 9.8, 6.1, 4.3, and 10.2, respectively, all greater than 3. When the sample concentration was 2.5 mg / ml, impurities A, impurity B, impurity C, impurity D, impurity F, impurity G, and other impurities could be detected when their concentration exceeded 0.004% of the test sample, indicating that the method had high detection sensitivity.

[0123] (5) Methodological Validation - Linearity and Range

[0124] Labetalol hydrochloride stock solution: prepared as described under "(2) Specificity".

[0125] Impurity stock solution: prepared as described under "(2) Specificity".

[0126] Linearity (quantitation limit): 1 ml of labetalol hydrochloride stock solution and 1 ml of impurity stock solution were precisely pipetted into a 100 ml volumetric flask, diluted to the mark with diluent, mixed well, and this was the linear solution.

[0127] Linearity (50%): 1 ml of labetalol hydrochloride stock solution and 1 ml of impurity stock solution were precisely pipetted into a 20 ml volumetric flask, diluted to the mark with diluent, mixed well, and this was the linear solution.

[0128] Linearity (100%): 1 ml of labetalol hydrochloride stock solution and 1 ml of impurity stock solution were precisely pipetted into a 10 ml volumetric flask, diluted to the mark with diluent, mixed well, and this was the linear solution.

[0129] Linearity (150%): 3 ml of labetalol hydrochloride stock solution and 3 ml of impurity stock solution were precisely pipetted into a 20 ml volumetric flask, diluted to the mark with diluent, mixed well, and this was the linear solution.

[0130] Linearity (200%): 2 ml of labetalol hydrochloride stock solution and 2 ml of impurity stock solution were precisely pipetted into a 10 ml volumetric flask, diluted to the mark with diluent, mixed well, and this was the linear solution.

[0131] Precisely 20 μl of each of the above linear solutions was injected into the liquid chromatograph, and the chromatogram was recorded. The concentration was plotted as the abscissa, and the peak area was plotted as the ordinate, and a linear regression equation was prepared. The correction factor for the impurity was calculated. The results are shown in Tables 11-17, Figure 5-Figure 11 .

[0132] The correction factor for the impurity = the slope of the linear regression equation for the main component / the slope of the linear regression equation for the impurity.

[0133] Table 11 Linearity-Impurity A

[0134]

[0135] Table 12 Linearity-Impurity B

[0136]

[0137] Table 13 Linearity-Impurity C

[0138]

[0139]

[0140] Table 14 Linearity-Impurity D

[0141]

[0142] Table 15 Linearity- Impurity F

[0143]

[0144]

[0145] Table 16 Linearity- Impurity G

[0146]

[0147] Table 17 Linearity- Labetalol Hydrochloride

[0148]

[0149]

[0150] The results showed that: Impurity A, Impurity B, Impurity C, Impurity D, Impurity F, Impurity G, Labetalol Hydrochloride in their respective concentration range, the correlation coefficient (r) of linear regression equation were greater than 0.995, the Y-axis intercept were within 10% of 100% response value, the RSD% of response factor were within 10%, all met the requirements, the linear relationship of the method was good.

[0151] (6) Methodology validation-robustness

[0152] The specificity solution was taken to investigate the robustness, and the results were as follows.

[0153] Table 18 Robustness results

[0154]

[0155] The results showed that: within 48h, the single impurity and total impurities had no obvious change, the solution stability was good, and the method had good robustness.

[0156] Example 2

[0157] Compared with Example 1, the only difference was that the elution program in the chromatographic conditions of HPLC was different, and the elution program of this example was as follows:

[0158]

[0159] The other conditions were the same as Example 1, and 20μl of blank solution (diluent), control solution, test solution, each impurity positioning solution and specificity solution was precisely measured and injected into the liquid chromatograph, and the specificity results were shown in the following table.

[0160] Table 19 Specificity results of Example 2

[0161]

[0162] The results show that the separation degree between each impurity and the preceding and following impurities in the specific solution is greater than 1.5, the separation degree is good, and the separation and detection method provided by the present invention has good specificity.

[0163] Example 3

[0164] Compared with Example 1, the only difference is that in the HPLC chromatographic conditions, mobile phase A is a 50 mmol / L perchlorate solution, the pH value of which is adjusted to 5.5 with perchloric acid; mobile phase B is tetrahydrofuran with 0.1% trifluoroacetic acid; detection wavelength is 265 nm; flow rate is 1.5 ml / min; column temperature is 20°C.

[0165] All other conditions were the same as in Example 1. 20 μl each of blank solution (diluent), reference solution, test solution, each impurity location solution, and specificity solution were accurately measured and injected into the liquid chromatograph. The specificity results are shown in the following table.

[0166] Table 20 Example 3 specificity results

[0167]

[0168] The results show that the separation degree between each impurity and the preceding and following impurities in the specific solution is greater than 1.5, the separation degree is good, and the separation and detection method provided by the present invention has good specificity.

[0169] Comparative Example 1

[0170] The difference from Example 1 lies in the difference in the mobile phases: in Comparative Example 1, mobile phase A was acetonitrile, and mobile phase B was a 0.1% by volume phosphoric acid solution. All other conditions were the same as in Example 1. 20 μl each of the blank solution (diluent), reference solution, test solution, each impurity localization solution, and specificity solution were accurately measured and injected into the liquid chromatograph. The specificity results are shown in the table below.

[0171] Table 21 Specificity results of comparative example 1

[0172]

[0173] The results show that the separation degree of some impurities is less than 1.5, which does not meet the requirements, indicating that the separation degree of the detection method of this comparative example is poor.

[0174] Comparative Example 2

[0175] The difference from Example 1 is that the elution procedure in the HPLC chromatographic conditions is different: the elution procedure of this comparative example is as follows:

[0176]

[0177] All other conditions were the same as in Example 1. 20 μl each of blank solution (diluent), reference solution, test solution, each impurity location solution, and specificity solution were accurately measured and injected into the liquid chromatograph. The specificity results are shown in the following table.

[0178] Table 22 Comparative Example 2 Specificity Results

[0179]

[0180] The results show that the separation degree of some impurities is less than 1.5, which does not meet the requirements, indicating that the separation degree of the detection method of this comparative example is poor.

[0181] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for separating and detecting impurities in labetalol hydrochloride injection, characterized in that: The separation and detection method adopts HPLC method; the chromatographic conditions of the HPLC method are: Chromatographic column: Propylsilane bonded silica gel as filler; Mobile phase: Mobile phase A is perchlorate buffer solution, and mobile phase B is tetrahydrofuran solution containing trifluoroacetic acid; The detection wavelength of the detector is 220-265 nm; Elution: Gradient elution, the elution program is as follows: 0 minutes, the amount of mobile phase A is 75%, and the amount of mobile phase B is 25%; 5 minutes, mobile phase A is 55%, mobile phase B is 45%; 15 minutes, mobile phase A is 35%, mobile phase B is 65%; 45 minutes, mobile phase A is 30%, mobile phase B is 70%; 55 minutes, mobile phase A is 75%, mobile phase B is 25%; The impurities are impurity A, impurity B, impurity C, impurity D, impurity F and impurity G; The structural formula of the impurity A is: The structural formula of the impurity B is: The structural formula of the impurity C is: The structural formula of the impurity D is: The structural formula of the impurity F is: The structural formula of the impurity G is: The source of the labetalol hydrochloride injection is Zhejiang Hemukang Pharmaceutical Technology Co., Ltd., batch number: Z-LAB2206015; the labetalol hydrochloride injection is dissolved in a diluent.

2. The separation and detection method according to claim 1, wherein: The mobile phase A is a perchlorate buffer solution, the concentration of the perchlorate buffer solution is 10-50 mmol / L, and the pH of the perchlorate buffer solution is 3.5-5.5; the mobile phase B is a tetrahydrofuran solution containing trifluoroacetic acid.

3. The separation and detection method according to claim 2, wherein: The mobile phase A is selected from any one or more of potassium perchlorate buffer solution, sodium perchlorate buffer solution, and ammonium perchlorate buffer solution; and the mobile phase B is a tetrahydrofuran solution containing 0.05%-0.2% trifluoroacetic acid.

4. The separation and detection method according to claim 3, wherein: The mobile phase A is a sodium perchlorate buffer solution with a concentration of 10-50 mmol / L and a pH of 3.5-5.5; the mobile phase B is a tetrahydrofuran solution containing 0.1% trifluoroacetic acid, v / v.

5. The separation and detection method according to claim 1, wherein: The flow rate of the mobile phase is 0.5-1.5 ml / min.

6. The separation and detection method according to claim 1, wherein: In the HPLC method, the injection volume is 5-50 μl, and the column temperature of the chromatographic column is 25-45°C.

7. The separation and detection method according to claim 1, wherein: The separation and detection method comprises the following steps: (1) Sample preparation: Dissolve the reference substance and test substance in a diluent to prepare reference substance solution and test substance solution respectively; (2) Using the chromatographic conditions of the HPLC method, perform high performance liquid chromatography analysis on the reference solution and the test solution.

8. Use of the separation and detection method according to any one of claims 1 to 7 in quality testing of labetalol hydrochloride injection.

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