A method for determining the impurity content in LH-2103 capsules using HPLC

Abstract

This invention discloses a method for determining the impurity content in LH-2103 capsules using HPLC, belonging to the field of pharmaceutical analysis technology. The invention employs a reversed-phase chromatographic column packed with C18, using phosphate buffer as mobile phase A and an organic solvent as mobile phase B, performing gradient elution to determine related substances in LH-2103 capsules. This method achieves excellent separation between acetylcholine, thrombocytidine, and impurities; other impurities, excipient peaks, and solvent peaks do not interfere with the detection; and minor changes in chromatographic parameters do not affect the separation and detection results of the main component and impurities, demonstrating good robustness. This method can rapidly, effectively, accurately, and reliably separate and detect impurities in LH-2103 capsules, which is beneficial for improving the product quality of LH-2103 capsules and enhancing patient safety.

Description

Technical Field

[0001] The invention belongs to the technical field of drug analysis, and particularly relates to a method for determining the impurity content in LH-2103 capsules by utilizing HPLC. Background Art

[0002] LH-2103 capsule is used to treat benign prostatic hyperplasia and improve the symptoms related to benign prostatic hyperplasia. It is a compound preparation of Aprilate and Silodosin (LH-2103 capsule is the drug prepared in Example 1 of patent application CN116726024A). Aprilate is a non-competitive type II 5α reductase inhibitor, which can inhibit the conversion of testosterone to dihydrotestosterone (DHT) in the body, thereby reducing the volume of the prostate and improving urination difficulties; Silodosin is an α receptor blocker, which can relax the smooth muscle of the prostate and bladder neck, improve urination disorders, and reduce the symptoms of benign prostatic hyperplasia. The combination of the two can target the urethral cavity stenosis and enhanced prostate smooth muscle tension caused by benign prostatic hyperplasia, and play the role of reducing the volume of the prostate and relaxing the smooth muscle respectively.

[0003] The results of clinical trials show that both Aprilate and Silodosin in LH-2103 capsules have a clear basis for effectiveness, and both drugs have good safety. The safety information suggests that the two drugs have no obvious overlap in toxicity spectra that requires warning, and are potential clinical candidate drugs for the treatment of benign prostatic hyperplasia.

[0004] LH-2103 capsules are not available in China or abroad, and there is no literature report on the analytical method of this preparation. In order to ensure the subsequent development and production quality of LH-2103 capsules, it is necessary to control its quality. Therefore, it is particularly urgent for pharmaceutical manufacturers to study and establish a method for quickly and effectively detecting the content of related substances in LH-2103 capsules. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a high performance liquid chromatography analysis method which has high feasibility, simple and convenient operation process, good applicability, and can be widely used in determining the content of related substances in LH-2103 capsules, fully meeting the qualitative and quantitative analysis of various impurities in the product, so that the product quality can be effectively controlled.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for determining the impurity content in LH-2103 capsules using HPLC comprises the following steps:

[0008] 1) Prepare test solution and control solution;

[0009] 2) Setting the HPLC detection conditions: using a reverse phase chromatographic column with C18 as the filler, the mobile phase is composed of phase A and phase B, wherein phase A is a potassium dihydrogen phosphate solution with a pH of 3.3 to 3.5, and phase B is an acetonitrile solution, and gradient elution is performed;

[0010] The gradient elution conditions are as follows: 0-5 min, the volume content of mobile phase A is 70-80%, and the volume content of mobile phase B is 20-30%; 5-12 min, the volume content of mobile phase A changes from 70-80% to 60-70%, and the volume content of mobile phase B changes from 20-30% to 30-40%; 12-25 min, the volume content of mobile phase A changes from 60-70% to 40-60%, and the volume content of mobile phase B changes from 30-40% to 40-60%; 25-35 min, the volume content of mobile phase A changes from 40-60% to 30-40%, and the volume content of mobile phase B changes from 40-60% to From 35 to 40 minutes, the volume content of mobile phase A changes from 30 to 40% to 10 to 30%, and the volume content of mobile phase B changes from 60 to 70% to 70 to 90%; From 40 to 65 minutes, the volume content of mobile phase A is 10 to 30%, and the volume content of mobile phase B is 70 to 90%; From 65 to 65.1 minutes, the volume content of mobile phase A changes from 10 to 30% to 70 to 80%, and the volume content of mobile phase B changes from 70 to 90% to 20 to 30%; From 65.1 to 75 minutes, the volume content of mobile phase A is 70 to 80%, and the volume content of mobile phase B is 20 to 30%;

[0011] 3) Accurately measure the test solution and the control solution, respectively, inject them into the liquid chromatograph, record the chromatogram, and calculate the linear regression equation of the control solution concentration value and the corresponding peak area value; the LH-2103 capsule is a compound preparation of Aprelet and Silodosin.

[0012] Preferably, in step 2), the gradient elution conditions are: 0-5 min, the volume content of mobile phase A is 78%, and the volume content of mobile phase B is 22%; 5-12 min, the volume content of mobile phase A changes from 78% to 60%, and the volume content of mobile phase B changes from 22% to 40%; 12-25 min, the volume content of mobile phase A changes from 60% to 55%, and the volume content of mobile phase B changes from 40% to 45%; 25-35 min, the volume content of mobile phase A changes from 55% to 35%, and the volume content of mobile phase B changes from 22% to 40%. The content changes from 45% to 65%; from 35 to 40 min, the volume content of mobile phase A changes from 35% to 25%, and the volume content of mobile phase B changes from 65% to 75%; from 40 to 65 min, the volume content of mobile phase A is 25%, and the volume content of mobile phase B is 75%; from 65 to 65.1 min, the volume content of mobile phase A changes from 25% to 78%, and the volume content of mobile phase B changes from 75% to 22%; from 65.1 to 75 min, the volume content of mobile phase A is 78%, and the volume content of mobile phase B is 22%.

[0013] More preferably, the pH of the potassium dihydrogen phosphate solution is 3.4.

[0014] Preferably, in step 2), the mobile phase flow rate is 0.95-1.05 mL / min, and the column temperature is 38-42° C. More preferably, the mobile phase flow rate is 1 mL / min, and the column temperature is 40° C.

[0015] Preferably, in step 2), the chromatographic column is Shim-pack GIST C18, with a specification of 4.6 mm×250 mm and a filler particle size of 5 μm.

[0016] Preferably, in step 3), the detection wavelength of the liquid chromatograph is 225 nm and 270 nm.

[0017] Preferably, the injection volume is 20 μL.

[0018] Preferably, in step 1), the preparation process of the test solution is: take the contents of LH-2103 capsules, add a diluent to dissolve and quantitatively dilute to prepare a solution containing 1 mg of eprite and 0.8 mg of silodosin per 1 mL, filter, and take the filtrate as the test solution.

[0019] The preparation process of the control solution is as follows: take 1mL of the test solution, place it in a 100mL volumetric flask, add diluent to dilute to the scale, then accurately measure 1mL, place it in a 10mL volumetric flask, and dilute to the scale with diluent as the control solution.

[0020] Preferably, the diluent is methanol-water, and the volume ratio of methanol to water is 7:3.

[0021] Preferably, in the step 3), according to the chromatogram, a linear regression equation is made with the peak area x as the ordinate and the concentration y as the abscissa. When the detection wavelength is 225 nm, the linear regression equation of Aprelet is y=0.1319x+0.0001, the linear regression equation of Aprelet impurity I is y=0.4559x-0.0103, the linear regression equation of silodosin is y=0.8208x-0.0194, and the linear regression equation of silodosin impurity A is y=1.1323x-0. 0852, the linear regression equation of silodosin impurity B is y=1.1118x-0.0226, the linear regression equation of silodosin impurity C is y=1.2601x-0.0152, and the linear regression equation of silodosin impurity D is y=1.0604x-0.014; when the detection wavelength is 270nm, the linear regression equation of aplid is y=1.1954x-0.0230, and the linear regression equation of aplid impurity II is y=1.1295x-0.0213.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0023] (1) The present invention adopts high performance liquid chromatography to determine the content of related substances in LH-2103 capsules, and can simultaneously analyze the content of eprite, silodosin and their impurities, thereby solving the interference of unknown impurities on the main components and known impurities;

[0024] (2) The present invention can achieve good separation between Aprelet, Silodosin and impurities; other impurities, auxiliary material peaks and solvent peaks do not interfere with the detection; the degradation products produced by the auxiliary materials and the test samples under various destruction conditions do not interfere with the determination of various impurities, and the detection specificity of related substances is good; at the same time, when the chromatographic condition parameters undergo slight changes, the separation and inspection results of the main components and impurities are not affected, and the durability is good;

[0025] (3) The present invention can quickly, effectively, accurately and reliably separate and detect the impurities of LH-2103 capsules, which is beneficial to improving the product quality of LH-2103 capsules and improving the safety of patients' medication. LH-2103 capsules are compound capsules and are also Class 2.3 new drugs. In order to ensure the quality of the drug and the safety of patients' medication, the present invention provides a corresponding detection method for the analysis of related substances in LH-2103 capsules, thereby solving the quality research work of LH-2103 capsules. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The chromatogram of the test solution in Example 1 is shown below:

[0027] Figure 2 is the system suitability chromatogram in Example 1;

[0028] Figure 3 It is the blank auxiliary material chromatogram in Example 1;

[0029] Figure 4 is the diluent chromatogram in Example 1;

[0030] Figure 5 It is silodosin impurity A (C 25 H 30 O 4 F 3 N 3 )’s standard curve diagram;

[0031] Figure 6 It is silodosin impurity B (C 25 H 30 O 3 F 3 N 3 )’s standard curve diagram;

[0032] Figure 7 is silodosin impurity C (C 22 H 25 O 2 N 3 ·C 4 H 6 O 6 )’s standard curve diagram;

[0033] Figure 8 It is the impurity D(C 32 H 34 O 4 F 3 N 3 )’s standard curve diagram;

[0034] Fig. 9 It is impurity I (C 24 H 37 NO 3 )’s standard curve diagram;

[0035] Fig.10 It is impurity II of Aprelet 26 H 39 NO 3 ) standard curve diagram. DETAILED DESCRIPTION

[0036] The present invention will be further illustrated below in conjunction with specific examples. The examples are implemented under the premise of the technical solution of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0037] The impurities of LH-2103 capsules in the following examples are: Silodosin impurity A (chemical formula: C 25 H 30 O 4 F 3 N 3 , process impurities and degradation impurities introduced by silodosin raw materials), silodosin impurity B (chemical formula: C 25 H 30 O 3 F 3 N 3 , process impurities introduced by silodosin raw materials), silodosin impurity C (chemical formula: C 22 H 25 O 2 N 3 ·C 4 H 6 O 6 , process impurities introduced by silodosin raw materials), silodosin impurity D (chemical formula: C 32 H 34 O 4 F 3 N 3 , process impurities introduced from silodosin raw materials), impurity I of Apretil (chemical formula: C 24 H 37 NO 3 , impurities introduced from the raw materials of Aprelet), Aprelet impurity II (chemical formula: C 26 H 39 NO 3 , the raw materials of Aplit introduce process impurities).

[0038] Example 1

[0039] (1) Testing conditions

[0040] Instrument: High performance liquid chromatograph Agilent 1260;

[0041] Detection wavelength: 225nm and 270nm;

[0042] Chromatographic column: Shim-pack GIST C18, size 4.6mm×250mm, filler particle size 5μm;

[0043] Mobile phase A: potassium dihydrogen phosphate solution (pH adjusted to 3.4 with phosphoric acid);

[0044] Mobile phase B: acetonitrile;

[0045] Gradient elution program: 0-5 min, the volume content of mobile phase A is 78%, and the volume content of mobile phase B is 22%; 5-12 min, the volume content of mobile phase A changes from 78% to 60%, and the volume content of mobile phase B changes from 22% to 40%; 12-25 min, the volume content of mobile phase A changes from 60% to 55%, and the volume content of mobile phase B changes from 40% to 45%; 25-35 min, the volume content of mobile phase A changes from 55% to 35%, and the volume content of mobile phase B changes from 45% to 56%. 65%; 35-40min, the volume content of mobile phase A changes from 35% to 25%, and the volume content of mobile phase B changes from 65% to 75%; 40-65min, the volume content of mobile phase A is 25%, and the volume content of mobile phase B is 75%; 65-65.1min, the volume content of mobile phase A changes from 25% to 78%, and the volume content of mobile phase B changes from 75% to 22%; 65.1-75min, the volume content of mobile phase A is 78%, and the volume content of mobile phase B is 22%;

[0046] Flow rate: 1 mL / min;

[0047] Column temperature: 40°C;

[0048] Injection volume: 20 μL.

[0049] (2) Detection steps

[0050] Test solution: Dissolve in diluent and quantitatively dilute to make a solution containing 1 mg of eprite and 0.8 mg of silodosin per 1 mL, filter, and take the filtrate as the test solution.

[0051] Control solution: Accurately measure 1 mL of the test solution, place it in a 100 mL volumetric flask, and dilute to the scale with diluent as the control solution.

[0052] The diluent is methanol-water, and the volume ratio of methanol to water is 7:3.

[0053] Accurately measure 20 μL of the control solution and the test solution respectively, inject them into the liquid chromatograph, detect at wavelengths of 225 nm and 270 nm, and record the chromatogram. The results are as follows: Figure 1-4 shown.

[0054] Depend on Figure 1 It can be seen that under the chromatographic conditions of Example 1, the main peaks of Aprilate and Silodosin can be well separated from the impurities, and the separation degree is shown in Table 1. The solvent peak does not interfere with the determination, which meets the standard.

[0055] Depend on Figure 2 It can be seen that the main components of Aprelet and Silodosin can be well separated from the impurities, and the separation degrees are all greater than 2.0, which meets the requirements.

[0056] Depend on Figure 3 It can be seen that the auxiliary materials have no interference with the main ingredients of Aprelet, Silodosin and various impurities.

[0057] Depend on Figure 4 It can be seen that the solvent peak has no interference with the main components of aprelet, silodosin and various impurities.

[0058] Example 2

[0059] The detection method of Example 1 was validated from the aspects of system applicability, destructive test, limit of quantification, limit of detection, linear relationship, precision, accuracy and solution stability.

[0060] (1) System applicability

[0061] Weigh appropriate amounts of reference substances of silodosin impurity A, silodosin impurity B, silodosin impurity C, silodosin impurity D, aplite impurity I and aplite impurity II, respectively, add diluent (methanol: water = 70:30) to dissolve and dilute to prepare impurity stock solutions containing 1 mg of each impurity reference substance per 1 mL; take appropriate amounts of each stock solution, add appropriate amounts of the contents of LH-2103 capsules into the same volumetric flask, add diluent (methanol: water = 70:30) to dissolve and dilute to prepare a mixed solution containing 1 mg of aplite, 0.8 mg of silodosin, 8 μg of silodosin impurity A, 2 μg of silodosin impurity B, 2 μg of silodosin impurity C, 2 μg of silodosin impurity D, 2 μg of aplite impurity I and 2 μg of aplite impurity II per 1 mL, filter, and take the filtrate as the system suitability solution.

[0062] Table 1: Impurity location and separation table

[0063] name Retention time Separation Theoretical plates Silodosin 13.323 4.2 24523 Silodosin Impurity A 14.350 14.6 149263 Silodosin Impurity B 16.827 5.1 121958 Silodosin Impurity C 17.797 29.5 139022 Aprelet Impurity I 24.997 22.8 112578 Silodosin Impurity D 31.513 18.3 210905 Aplita 36.677 33.6 255258 Apretil Impurity II 47.113 na 322839

[0064] (2) Destructive testing

[0065] The contents of LH-2103 capsules were taken to prepare the destructive test solution. The destructive investigation results are shown in Table 2.

[0066] Undamaged solution: Take the contents of LH-2103 capsules, dissolve and dilute to scale with solvent, filter, and take the filtrate to prepare an undamaged solution.

[0067] Acid degradation test solution: Take the contents of LH-2103 capsules, heat them with strong acid at 80℃, neutralize them, dilute them to the scale with solvent, filter them, and take the filtrate to prepare the acid degradation solution.

[0068] Alkali degradation test solution: Take the contents of LH-2103 capsules, place them at room temperature with strong alkali, neutralize them, dilute them to the scale with solvent, filter them, and take the filtrate to prepare the alkaline degradation solution.

[0069] Oxidative degradation test solution: Take the contents of LH-2103 capsules, place them at room temperature after passing through 5% hydrogen peroxide solution, dilute them to the scale with a solvent, filter, and take the filtrate to prepare an oxidative degradation test solution.

[0070] Photodegradation test solution: Take the contents of LH-2103 capsules, add solvent to dissolve and make up to the scale, irradiate under strong light conditions, filter, take the filtrate, and prepare the photodegradation test solution.

[0071] High temperature degradation test solution: Take the contents of LH-2103 capsules, place them at high temperature conditions of 105°C, dissolve them with solvent and make up to the scale, filter, take the filtrate, and prepare the high temperature degradation test solution.

[0072] Thermal degradation test solution: Take the contents of LH-2103 capsules, add 2 mL of solvent to dissolve, place at high temperature conditions of 80°C, dissolve with solvent and make up to the scale, filter, take the filtrate, and prepare the thermal degradation test solution.

[0073] Table 2: Damage investigation results

[0074]

[0075] As shown in Table 2, the material balance under each degradation test condition is between 90% and 108%, and the purity of the main peak meets the requirements. The acid blank, base blank and oxidation blank solvents do not interfere with the detection, and the specificity is good.

[0076] (3) Limit of quantification and limit of detection test

[0077] The limit of quantification (S / N≥10) and limit of detection (S / N≥3) were determined by serial dilution method. The results are shown in Table 3.

[0078] Table 3: Limits of detection and limits of quantitation

[0079]

[0080] (4) Injection precision

[0081] Under the chromatographic conditions of Example 1, the sample was injected six times continuously. The injection precision results are shown in Tables 4 and 5.

[0082] Table 4: Injection precision results when the detection wavelength is 225nm

[0083]

[0084]

[0085] Table 5: Injection precision results when the detection wavelength is 270nm

[0086]

[0087] It can be seen from Tables 4 and 5 that the RSD of the peak areas of the known impurities and main peaks of the six injection precision samples is ≤2%, and the injection precision is good.

[0088] (5) Solution stability

[0089] Under the chromatographic conditions of Example 1, the sample was injected within 40 hours to investigate its intra-day stability. The stability results are shown in Table 6.

[0090] Table 6: Solution stability results

[0091]

[0092]

[0093] It can be seen from Table 6 that the known impurities, the maximum unknown single impurity and the total impurity are all within the 0H limit of ≤5%, and the solution is stable within 40 hours.

[0094] (6) Linearity and range

[0095] Under the chromatographic conditions of Example 1, solutions were prepared at 6%, 16%, 20%, 50%, 80%, 100%, and 200% limits, and standard curves were drawn. The results are shown in Tables 7 and Figure 5-10 shown.

[0096] Table 7: Related substances - relative correction factor calculation results

[0097]

[0098]

[0099] Depend on Figure 5-10 As shown in Table 7, Aprelet, Silodosin and the six impurities are linear in the limit concentration range of 6% to 200%, and r is greater than 0.999. The relative correction factor ratios of each impurity are in the range of 0.2 to 5, which meets the quantitative requirements of adding correction factors.

[0100] (7) Repeatability

[0101] Take an appropriate amount of the content of LH-2103 capsules, add diluent (methanol: water = 70:30) to dissolve and quantitatively dilute to make a solution containing approximately 1 mg of eprite and 0.8 mg of silodosin per 1 mL, filter, take the filtrate for sampling, and examine the absolute value of the difference between each impurity and the mean value of the test results in the 6 samples as a repeatability inspection indicator. The results are shown in Table 8.

[0102] Table 8: Repeatability test table

[0103]

[0104] It can be seen from Table 8 that the absolute value of the difference between each impurity and the mean in the 6 repeatability samples is ≤ 5% of the limit, and the repeatability is good.

[0105] (8) Intermediate precision

[0106] According to the repeatability item, the same method was performed on different days, different instruments, and by different people, and the precision of each impurity content measured in three experiments was calculated. The results are shown in Table 9.

[0107] Table 9: Intermediate precision test table

[0108]

[0109] It can be seen from Table 9 that the absolute value of the difference between each impurity and the mean is ≤10% of the limit, and the intermediate precision is good.

[0110] (9) Recovery rate

[0111] Take an appropriate amount of the contents of LH-2103 capsules, a total of 9 portions, and place them in 9 20mL volumetric bottles. Accurately add an appropriate amount of impurity reserve solution to each, dissolve it with a solvent to 20mL, so that the concentration of each impurity to be tested is 50%, 100%, and 200% of the limit concentration, respectively, and three portions of each concentration are used as the recovery test solution. Take 20μL of the above test solution and 0.1% control solution, inject them separately, and record the chromatogram. Record the peak area, calculate the measured amount of each impurity by the main component self-control method with correction factor, and calculate the recovery. The results of the sample recovery determination are shown in Tables 10-15 respectively.

[0112] Table 10: Results of sample recovery of silodosin impurity A

[0113]

[0114]

[0115] Table 11: Results of sample recovery of silodosin impurity B

[0116]

[0117] Table 12: Results of sample recovery of silodosin impurity C

[0118]

[0119]

[0120] Table 13: Results of sample recovery of silodosin impurity D

[0121]

[0122] Table 14: Results of sample recovery determination of impurity I in Aprilate

[0123]

[0124] Table 15: Results of sample recovery determination of impurity II of Aprelet

[0125]

[0126]

[0127] (10) Robustness of HPLC method for related substances

[0128] Referring to the guidance of the validation of analytical methods for drug quality standards in the General Chapter 9101 of the Chinese Pharmacopoeia, the durability test of the method for the related substances of LH-2103 capsules was carried out. The system suitability solution was sampled, and the column temperature (±2°C), flow rate (±0.05mL / min), aqueous phase pH value (±0.1), and aqueous phase initial ratio (±0.5%) were changed respectively. The theoretical plate numbers of the aplite peak and the silodosin peak, the separation degree between the main peak and the adjacent impurities, and the separation degree between the impurities were investigated. The durability research project was carried out for the chromatographic conditions of Example 1. The specific results are shown in Table 16 below.

[0129] Table 16: Robustness of HPLC Methods for Related Substances

[0130]

[0131] As shown in Table 16, by changing the column temperature (±2°C), flow rate (±0.05mL / min), aqueous phase pH value (±0.1), and aqueous phase initial ratio (±0.5%), the separation degrees of adjacent impurity peaks and the aplenate peak and sildosin peak are all greater than 1.5, and each impurity can be effectively separated, indicating that this method has good durability.

[0132] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for determining the impurity content in LH-2103 capsules using HPLC, characterized in that: The following steps are involved: 1) Prepare test solution and control solution; 2) Setting the HPLC detection conditions: using a reverse phase column with C18 as the filler, the mobile phase consists of phase A and phase B, where phase A is a potassium dihydrogen phosphate solution with a pH of 3.3-3.5, and phase B is an acetonitrile solution, and gradient elution is performed; The gradient elution conditions were as follows: 0-5 min, the volume content of mobile phase A was 70-80%, and the volume content of mobile phase B was 20-30%; 5-12 min, the volume content of mobile phase A changed from 70-80% to 60-70%, and the volume content of mobile phase B changed from 20-30% to 30-40%; 12-25 min, the volume content of mobile phase A changed from 60-70% to 40-60%, and the volume content of mobile phase B changed from 30-40% to 40-60%; 25-35 min, the volume content of mobile phase A changed from 40-60% to 30-40%, and the volume content of mobile phase B changed from 40-60% to From 35 to 40 minutes, the volume content of mobile phase A changes from 30 to 40% to 10 to 30%, and the volume content of mobile phase B changes from 60 to 70 to 70%; From 40 to 65 minutes, the volume content of mobile phase A is 10 to 30%, and the volume content of mobile phase B is 70 to 90%; From 65 to 65.1 minutes, the volume content of mobile phase A changes from 10 to 30% to 70 to 80%, and the volume content of mobile phase B changes from 70 to 90% to 20 to 30%; From 65.1 to 75 minutes, the volume content of mobile phase A is 70 to 80%, and the volume content of mobile phase B is 20 to 30%; 3) Accurately measure the test solution and the control solution, respectively, inject them into the liquid chromatograph, record the chromatogram, and calculate the linear regression equation of the control solution concentration value and the corresponding peak area value; the LH-2103 capsule is a compound preparation of Aprelet and Silodosin.

2. The method for determining the impurity content in LH-2103 capsules by HPLC according to claim 1, characterized in that: In the step 2), the gradient elution conditions are: 0-5 min, the volume content of mobile phase A is 78%, and the volume content of mobile phase B is 22%; 5-12 min, the volume content of mobile phase A changes from 78% to 60%, and the volume content of mobile phase B changes from 22% to 40%; 12-25 min, the volume content of mobile phase A changes from 60% to 55%, and the volume content of mobile phase B changes from 40% to 45%; 25-35 min, the volume content of mobile phase A changes from 55% to 35%, and the volume content of mobile phase B changes from 40% to 45%. From 45% to 65%; from 35 to 40 min, the volume content of mobile phase A changed from 35% to 25%, and the volume content of mobile phase B changed from 65% to 75%; from 40 to 65 min, the volume content of mobile phase A was 25%, and the volume content of mobile phase B was 75%; from 65 to 65.1 min, the volume content of mobile phase A changed from 25% to 78%, and the volume content of mobile phase B changed from 75% to 22%; from 65.1 to 75 min, the volume content of mobile phase A was 78%, and the volume content of mobile phase B was 22%.

3. The method for determining the impurity content in LH-2103 capsules by HPLC according to claim 1, characterized in that: In the step 2), the flow rate of the mobile phase is 0.95-1.05 mL / min, and the column temperature is 38-42°C.

4. The method for determining the impurity content in LH-2103 capsules by HPLC according to claim 1, characterized in that: In the step 2), the chromatographic column is Shim-pack GIST C18, with a specification of 4.6 mm×250 mm and a filler particle size of 5 μm.

5. The method for determining the impurity content in LH-2103 capsules by HPLC according to claim 1, characterized in that: In the step 3), the detection wavelengths of the liquid chromatograph are 225 nm and 270 nm.

6. The method for determining the impurity content in LH-2103 capsules by HPLC according to claim 1, characterized in that: In the step 1), the preparation process of the test solution is as follows: take the contents of LH-2103 capsules, add a diluent to dissolve and quantitatively dilute to prepare a solution containing 1 mg of eprite and 0.8 mg of silodosin per 1 mL, filter, and take the filtrate as the test solution.

7. The method for determining the impurity content in LH-2103 capsules by HPLC according to claim 6, characterized in that: The diluent is methanol-water, and the volume ratio of methanol to water is 7:

3.

8. The method for determining the impurity content in LH-2103 capsules by HPLC according to claim 1, characterized in that: In the step 3), according to the chromatogram, a linear regression equation is made with the peak area x as the ordinate and the concentration y as the abscissa. When the detection wavelength is 225 nm, the linear regression equation of Aprelet is y=0.1319x+0.0001, the linear regression equation of Aprelet impurity I is y=0.4559x-0.0103, the linear regression equation of silodosin is y=0.8208x-0.0194, and the linear regression equation of silodosin impurity A is y=1.1323x-0.085 2. The linear regression equation of silodosin impurity B is y=1.1118x-0.0226, the linear regression equation of silodosin impurity C is y=1.2601x-0.0152, and the linear regression equation of silodosin impurity D is y=1.0604x-0.014; when the detection wavelength is 270nm, the linear regression equation of Aprelet is y=1.1954x-0.0230, and the linear regression equation of Aprelet impurity II is y=1.1295x-0.0213.

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