A method for determining the dissolution curve of fenelazol tablets

Abstract

This invention belongs to the field of pharmaceutical analysis technology and discloses a method for determining the dissolution curve of phenelzine tablets. The method uses a pH 4.5 acetate buffer containing 0.05%-0.2% polysorbate 20 as the dissolution medium, with a volume of 800-1000 ml, and dissolution is performed using a paddle method at a speed of 70-80 rpm and a temperature of 36.5℃-37.5℃. The dissolution solution is collected at multiple time points, filtered, and analyzed by high-performance liquid chromatography (HPLC). The chromatographic conditions are: an octadecylsilane-bonded silica gel column; a mobile phase of potassium dihydrogen phosphate buffer (pH 2.8-3.2) mixed with acetonitrile at a volume ratio of 65:35-75:25; and a detection wavelength of 245-255 nm. The cumulative dissolution amount is calculated using the external standard method. This method is highly specific, accurate, and robust, and can effectively determine the dissolution curve of phenelzine tablets, making it suitable for their quality control and evaluation.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical analysis technology, and in particular to a method for determining the dissolution curve of fenelazol tablets. Background Technology

[0002] Finerenone is a novel nonsteroidal mineralocorticoid receptor antagonist that selectively blocks mineralocorticoid receptors, inhibiting inflammation and fibrosis. Clinically, it is primarily used to treat chronic kidney disease associated with type 2 diabetes. Due to its proven efficacy and good safety profile, quality control of finerenone tablets is crucial for ensuring the safety and effectiveness of clinical use. As a core indicator of drug quality control, the accuracy and reliability of analytical methods for content determination directly impact product quality assessment.

[0003] Currently, there are some reported techniques for the determination of fenelazol tablet content. The most common method is high-performance liquid chromatography (HPLC), which achieves the separation and quantification of the main component by selecting appropriate chromatographic columns, mobile phases, and detection wavelengths. However, these existing methods still have the following technical limitations in practical applications: First, the analysis time is long. Some methods use gradient elution or long column equilibration times, resulting in excessively long single analysis cycles, which makes it difficult to meet the needs of high-throughput sample detection and reduces quality control efficiency.

[0004] Second, the specificity is insufficient. Existing methods have limited ability to separate excipients, known impurities, and potential degradation products. Especially under forced degradation test conditions, the main peak is prone to overlap or encapsulation with adjacent impurity peaks, which cannot accurately reflect the true content of the main component and affects the specificity and accuracy of the method.

[0005] Third, the sensitivity and robustness are poor. Some methods do not respond well in the low concentration linear range, or are sensitive to small changes in chromatographic conditions (such as mobile phase pH, column temperature, flow rate, etc.), resulting in poor reproducibility between different laboratories or different operators, making it difficult to promote and apply the methods.

[0006] Fourth, the operation is cumbersome. Some methods involve complex sample pretreatment steps or multiple dilution steps, which not only increases the risk of operational errors but also places higher demands on the technical skills of the testing personnel. Summary of the Invention

[0007] To overcome the technical defects of the existing technology, the present invention provides a method for determining and analyzing the dissolution curve of phenelzine tablets, comprising the following steps: Step 1, preparing a pH 4.5 acetate buffer solution containing 0.05%-0.2% polysorbate 20 as the dissolution medium; Step 2: Take 6-12 fenelinedone tablets, use 800-1000ml of the dissolution medium as solvent, and use a paddle method at a speed of 70-80 rpm and a temperature of 36.5℃-37.5℃. Take the dissolution solution at multiple preset time points, filter it through a filter membrane, discard 1-4ml of the initial filtrate, and take the subsequent filtrate as the test solution. Step 3: Take fenelazol reference standard, dissolve it in acetonitrile, and then dilute it with the dissolution medium to prepare a reference standard solution; Step 4: The determination was performed using high performance liquid chromatography (HPLC). The chromatographic conditions were as follows: the column was packed with octadecylsilane-bonded silica gel; the mobile phase was a mixture of 0.005-0.02 mol / L potassium dihydrogen phosphate buffer (pH 2.8-3.2) and acetonitrile at a volume ratio of 65:35-75:25; the detection wavelength was 245-255 nm; the flow rate was 0.8-1.2 ml / min; the column temperature was 25-35 ℃; and the injection volume was 5-20 μl. Step 5: Calculate the cumulative dissolution of fenelazol at each time point using the peak area method according to the external standard method.

[0008] Preferably, the dissolution medium in step 1 is a pH 4.5 acetate buffer containing 0.1% polysorbate 20.

[0009] Preferably, in step 2, the volume of the dissolution medium is 900 ml, the rotation speed is 75 rpm, the temperature is 37℃±0.5℃, and the preset time points include 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, and 45 minutes.

[0010] Preferably, in step 2, the filter membrane is a polyethersulfone filter membrane with a pore size of 0.45 μm, and the volume of the discarded initial filtrate is 2 ml.

[0011] Preferably, the concentration of the reference solution in step 3 is 22.2 μg / ml.

[0012] Preferably, in step 4, the chromatographic column is an Inertsil ODS-3 with dimensions of 4.6 mm × 50 mm and a diameter of 5 μm; the mobile phase is a mixture of 0.01 mol / L potassium dihydrogen phosphate buffer and acetonitrile at a volume ratio of 70:30, the pH of the potassium dihydrogen phosphate buffer is 3.0; the detection wavelength is 250 nm, the flow rate is 1.0 ml / min, the column temperature is 30 °C, and the injection volume is 10 μl.

[0013] Preferably, the robustness range of the chromatographic conditions in step 4 is as follows: column temperature 30℃±5℃, flow rate 1.0ml / min±0.1ml / min, mobile phase ratio 68:32-72:28, and mobile phase pH 3.0±0.2.

[0014] Preferably, the allowable range of durability for the dissolution operation in step 2 is: rotation speed 75 rpm ± 5 rpm, temperature 37℃ ± 1℃.

[0015] Preferably, the fenelitonee tablets are in the form of 20 mg.

[0016] Preferably, when determining the dissolution curve of fenelitonee tablets using the method described above, the reference solution is injected continuously for 6 injections, the relative standard deviation of the retention time of the main peak is not greater than 1%, and the relative standard deviation of the peak area is not greater than 2%; the relative standard deviation of the dissolution of the 6 test solutions at 30 minutes is not greater than 10%, and the relative standard deviation of the cumulative dissolution at each time point after 5 minutes is not greater than 10%.

[0017] The beneficial effects of this invention are: 1. This invention optimizes the dissolution medium of polysorbate 20 in pH 4.5 acetate buffer, combines the paddle method and high performance liquid chromatography, and uses a short column, a mobile phase of pH 3.0 potassium dihydrogen phosphate buffer-acetonitrile (70:30), and a detection wavelength of 250 nm. This invention achieves the determination of the dissolution curve of fenelazol tablets with high specificity, high accuracy, good precision, wide linear range, good stability, and strong durability, which can reliably meet its quality control requirements. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the various embodiments of this invention will be described in detail below. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this invention to facilitate a better understanding of this application. However, the technical solutions claimed in the claims of this application can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0019] This embodiment provides a method for determining the dissolution curve of fenelazol tablets. The instruments used included: High-performance liquid chromatography (HPLC): A Thermo Vanquish Core HPLC system and a Shimadzu LC-40D HPLC system, both equipped with UV detectors, were used for chromatographic analysis of the samples. Dissolution apparatus: A DS-1206 dissolution apparatus and an RC-12AD dissolution apparatus, both paddle-type devices, were used for dissolution tests of fenelazol tablets. Electronic balance: A BSA124S electronic balance and an XSR105DU electronic balance were used for accurate weighing of reference standards and samples. pH meter: An SD20kit pH meter was used for determining and adjusting the pH value of the dissolution medium. High-speed centrifuge: A KDC-160HR high-speed centrifuge was used for centrifuging samples in the filter membrane adsorption test. The reagents used were: fenelazol reference standard: batch number 452-1-240501, with a content of 99.7%, used for preparing the reference solution. Fenelazol tablets: batch number 241002, 20mg specification, used as the test sample. Blank tablets: batch number 241001, containing no active ingredient, used for blank excipient interference tests. Acetonitrile: chromatographic grade, batch number A013124110D, used as the solvent and organic phase of the mobile phase. Potassium dihydrogen phosphate: analytical grade, batch number 20221223, used for preparing the mobile phase buffer. Phosphoric acid: analytical grade, batch number 230420126E, used to adjust the pH of the mobile phase. Sodium acetate trihydrate: analytical grade, batch number 240525D1, used for preparing the dissolution medium. Glacial acetic acid: analytical grade, batch number 240823A1, used for preparing the dissolution medium. Polysorbate 20: analytical grade, batch number Lf1208188594, added as a surfactant to the dissolution medium.

[0020] Preparation of dissolution medium: Weigh 2.99 g of sodium acetate trihydrate, add 1.6 ml of glacial acetic acid and 1.0 g of polysorbate 20, then dilute with water to 1.0 L. Adjust the pH to 4.5 ± 0.05 with diluted sodium hydroxide solution, and mix thoroughly to obtain a pH 4.5 acetate buffer containing 0.1% polysorbate 20. This dissolution medium is used for the dissolution test of phenelzine tablets.

[0021] Chromatographic conditions were set as follows: Column: Inertsil ODS-3 column, 4.6 mm × 50 mm, with a packing particle size of 5 μm.

[0022] Mobile phase: Prepare a 0.01 mol / L potassium dihydrogen phosphate buffer solution. Take 1.36 g of potassium dihydrogen phosphate, dilute it with water to 1000 ml, and adjust the pH to 3.0 with phosphoric acid. Mix this buffer solution with acetonitrile at a volume ratio of 70:30 as the mobile phase. Flow rate: Set to 1.0 ml / min. Detection wavelength: Set to 250 nm. Column temperature: Set to 30 °C. Injection volume: Set to 10 μl. Elution method: Isocratic elution. Detection time: Set to 4 minutes.

[0023] Preparation of the reference solution: Accurately weigh approximately 22.2 mg of fenelazol reference standard, place it in a 20 ml volumetric flask, dissolve and dilute to the mark with acetonitrile, and shake well to obtain the reference standard stock solution. Accurately measure 4 ml of the reference standard stock solution, place it in a 200 ml volumetric flask, dilute to the mark with dissolution medium, and shake well to obtain the reference standard solution with a concentration of 22.2 μg / ml.

[0024] Preparation of the test solution (dissolution profile): Take 6 fenelazol tablets and place them into 6 dissolution vessels respectively. Follow the procedure (paddle method) according to General Chapter 0931, Section II, Part IV of the 2020 edition of the Chinese Pharmacopoeia, using 900 ml of the dissolution medium prepared in Example 2 as the dissolution medium. The rotation speed is 75 rpm, and the temperature is 37°C. After 5, 10, 15, 20, 30, and 45 minutes, take 10 ml of the dissolution solution and immediately add an equal volume of fresh dissolution medium at the same temperature. Take the dissolution solution at each time point, discard 2 ml of the initial filtrate, filter through a 0.45 μm polyethersulfone membrane, and use the subsequent filtrate as the test solution.

[0025] Specificity test: Prepare the following solutions.

[0026] pH 4.5 acetate buffer containing 0.1% polysorbate 20: Weigh 2.99g of sodium acetate trihydrate, add 1.6ml of glacial acetic acid and 1.0g of polysorbate 20, dilute with water to 1.0L, adjust the pH to 4.5 with diluted sodium hydroxide or glacial acetic acid, mix well, and the buffer is ready.

[0027] Test solution: Take one tablet of this product and place it in a dissolution vessel. Perform the dissolution and release assay according to the method (Chinese Pharmacopoeia 2020 Edition, Part IV, General Chapter 0931, Method II), using 900 ml of pH 4.5 acetate buffer containing 0.1% polysorbate 20 as the dissolution medium and a rotation speed of 75 rpm. After 30 minutes, take a sample and collect 10 ml of the dissolution solution. Filter the solution through a 0.45 μm polyethersulfone filter membrane and collect the filtrate.

[0028] Reference solution: The reference stock solution is prepared by accurately weighing about 55.5 mg of fenelitonee reference standard, placing it in a 50 ml volumetric flask, adding solvent, sonicating to dissolve and diluting to the mark, and shaking well; the reference solution is prepared by accurately measuring 2 ml of the reference stock solution and placing it in a 100 ml volumetric flask, diluting to the mark with dissolution medium, and shaking well.

[0029] Blank excipients: Take one blank tablet and place it in different dissolution vessels for easy preparation. Accurately measure 10 μl of each of the above solutions and inject them into the liquid chromatograph, recording the chromatograms.

[0030] The experimental results showed that no chromatographic peak appeared at the retention time of the phenelzine main peak in the blank medium and blank excipient, and therefore did not interfere with the determination of the main peak. The retention time of the main peak in the test solution was 2.488 min, which was basically consistent with the retention time of 2.487 min in the reference solution, indicating that the main peak in the test solution was indeed phenelzine. This method has good specificity and meets the validation requirements.

[0031] Membrane adsorption test: Take one fenelazol tablet and place it in a dissolution vessel. Use a pH 4.5 acetate buffer containing 0.1% polysorbate 20 as the dissolution medium and rotate at 75 rpm. Perform the procedure according to the instructions and take samples after 5 minutes, 30 minutes, and 45 minutes. Take 20 ml of the dissolution solution, centrifuge 10 ml at 10,000 rpm for 10 minutes, and collect the supernatant; take another 10 ml and filter it through a 0.45 μm polyethersulfone membrane. Discard 0 ml, 2 ml, 4 ml, 6 ml, and 8 ml respectively, and collect the subsequent filtrates. Inject and determine the chromatographic conditions according to Example 3, record the peak area, and calculate the adsorption rate.

[0032] The formula for calculating the adsorption rate is: ; Wherein: A filtration: the peak area of ​​the main peak of the test solution filtered through different volumes; A centrifugation: the peak area of ​​the main peak of the supernatant of the test solution after centrifugation.

[0033] The acceptable standard in this operation is that the filter membrane adsorption rate should not exceed 2%.

[0034] The measurement results are shown in the following table:

[0035] Results Evaluation: The experimental results show that when using a polyethersulfone needle filter (model: 25mm, 0.45μm) for filtration, if the initial filtrate is not discarded and filtration is performed directly, the membrane adsorption rates of the dissolution solution at 5 minutes, 30 minutes, and 45 minutes are 15.5%, 10.0%, and 23.5%, respectively, all greater than 2%, indicating that the membrane has a significant adsorption effect on phenelzine. When 2 ml or more of the initial filtrate is discarded, the membrane adsorption rate of the dissolution solution at each time point is less than 2%. Therefore, it is determined that 2 ml of the initial filtrate should be discarded during sample filtration to ensure the accuracy of the measurement results.

[0036] Solution stability test: The reference solution and the test solution were placed at room temperature for 0 hours, 4 hours, 8 hours, 13 hours, 17 hours, 21 hours, 36 hours, 40 hours, 49 hours, 84 hours, 98 hours and 162 hours, respectively. The samples were injected and measured according to the chromatographic conditions of Example 3. The peak areas were recorded and the ratio of the peak area at 0 hours to the peak area at 0 hours was calculated.

[0037] The measurement results are shown in the following table:

[0038] Results Evaluation: The experimental results show that, after standing at room temperature for 162 hours, the ratio of the main peak area to the 0-hour peak area of ​​the reference solution was between 98.5% and 100.1%; after standing at room temperature for 84 hours, the ratio of the main peak area to the 0-hour peak area of ​​the test solution was between 98.4% and 99.6%. All ratios were within the required range of 98.0% to 102.0%, indicating that the reference solution and the test solution have good stability after standing at room temperature for 162 hours and 84 hours, respectively, and can meet the time requirements for routine analytical detection.

[0039] Linearity and range test: Accurately weigh approximately 55.5 mg of fenelazol reference standard, place it in a 50 mL volumetric flask, dissolve and dilute to the mark with acetonitrile, and shake well to prepare the linear stock solution. Quantitatively dilute the linear stock solution with dissolution medium according to the table below to prepare solutions of 10%–120% of the limit concentration. Dilute with pH 4.5 acetate buffer containing 0.1% polysorbate 20 to prepare the linear solution.

[0040] Under chromatographic conditions, accurately measure 10 μl of each of the above linear solutions, inject them into the liquid chromatograph, and record the chromatogram. Prepare two aliquots for each concentration point, inject them separately, and take the average peak area.

[0041] The measurement results are shown in the following table:

[0042] Linear regression was performed with concentration as the x-axis (X, unit mg / ml) and peak area as the y-axis, yielding the regression equation: Y = 34773825.6X - 413.26, with a correlation coefficient r = 1.0000.

[0043] The response factor (peak area / concentration) was calculated for each concentration point. The mean response factor was 34,774,425.9, and the relative standard deviation (RSD) of the response factor was 0.4%. The absolute value of the y-intercept was 413.26, which is 0.0% of the 100% response value (762,470).

[0044] Results Evaluation: The experimental results show that fenelazol, within the concentration range of 0.002 mg / ml to 0.026 mg / ml, corresponds to 10% to 120% of the limit concentration, and the peak area shows a good linear relationship with the concentration. The correlation coefficient r = 1.0000, greater than the requirement of 0.998; the ratio of the y-intercept to the 100% response value is 0.0%, less than the requirement of 2%; and the response factor RSD is 0.4%, less than the requirement of 2%. All the above results meet the validation requirements, indicating that the method has a good linear relationship. Accuracy Test: Prepare the reference solution. Take an appropriate amount of the recovery stock solution (linear stock solution) and prepare three parallel recovery solutions at five concentration levels: 10%, 50%, 80%, 100%, and 120%. The specific preparation method is shown in the table below:

[0045] Take one blank tablet and place it in a dissolution vessel. Follow the procedure in Example 5. After 30 minutes, take a sample to obtain the blank excipient solution. Accurately measure the recovery stock solution and place it in the corresponding volumetric flask. Dilute to the mark with the blank excipient solution, shake well, and filter to obtain the recovery solution. Inject and determine the peak area under the chromatographic conditions of Example 3. Calculate the recovery rate using the external standard method.

[0046] The measurement results are shown in the following table:

[0047] Results Evaluation: The experimental results show that the average recovery rate was 98.1% at the 10% concentration level; 101.0% at the 50% concentration level; 100.0% at the 80% concentration level; 100.2% at the 100% concentration level; and 101.2% at the 120% concentration level. The average recovery rates at all concentration levels were within the required range of 95%–105%. The overall average recovery rate of all 15 recovery solutions was 100.1%, with a relative standard deviation (RSD) of 1.2%, less than the requirement of 3%. All the above results meet the validation requirements, indicating that the method has good accuracy.

[0048] Injection precision test: Prepare reference solution, accurately measure 10 μl and inject into the liquid chromatograph, inject 6 times consecutively, record the chromatogram, and calculate the relative standard deviation of the retention time and peak area of ​​the main peak.

[0049] The measurement results are shown in the following table:

[0050] Results Evaluation: The experimental results show that after six consecutive injections of the reference solution, the relative standard deviation (RSD) of the main peak retention time was 0.2%, less than the requirement of 1%; the relative standard deviation (RSD) of the main peak area was 0.1%, less than the requirement of 2%. All these results meet the validation requirements, indicating that the instrument has good injection precision and the system's suitability meets the requirements.

[0051] Repeatability test: Prepare a reference solution, a test solution (dissolution rate), and a test solution (dissolution curve). Prepare 6 parallel test solutions. Calculate the dissolution rate of the 6 test solutions and the cumulative dissolution rate at each time point using the external standard method, and calculate the relative standard deviation.

[0052] The dissolution repeatability results are shown in the following table:

[0053] The repeatability results of the dissolution curves are shown in the table below:

[0054] As shown in the two charts above, the dissolution repeatability test results indicate that the dissolution rates of the six test solutions at 30 minutes were between 96% and 99%, with a mean of 98% and a relative standard deviation (RSD) of 0.9%, which is below the requirement of 10%, thus meeting the validation requirements. The dissolution curve repeatability test results show that, except for the 5-minute time point, the cumulative dissolution RSDs of the six test solutions at 10, 15, 20, 30, and 45 minutes were 5.6%, 1.4%, 0.8%, 0.9%, and 1.2%, respectively, all below the requirement of 10%. The RSD at the 5-minute time point was 8.0%, slightly higher than other time points, but still within an acceptable range. This may be related to differences in sample homogeneity during the initial dissolution phase. All the above results meet the validation requirements, indicating that the method has good repeatability.

[0055] Intermediate precision test: A repeatability test was performed by another analyst at a different time (November 30, 2024) on a different instrument (Thermo Vanquish Core), and the method of Example 12 was used. The dissolution and cumulative dissolution of a total of 12 solutions from the two repeatability tests were calculated, and the relative standard deviation was calculated.

[0056] The intermediate precision results for dissolution are shown in the following table:

[0057] Results evaluation: The intermediate precision test results of dissolution showed that the dissolution rate of the 12 test solutions was between 96% and 99% after 30 minutes, with an average of 97% and a relative standard deviation (RSD) of 0.9%, which is no more than 10%, and meets the verification requirements.

[0058] The intermediate precision test results of the dissolution profiles showed that, except for the 5-minute time point, the cumulative dissolution RSDs of the 12 test solutions at 10, 15, 20, 30, and 45 minutes were 5.3%, 1.9%, 1.6%, 1.7%, and 1.3%, respectively, all below the requirement of 10%. The RSD at the 5-minute time point was 18.3%, slightly higher than the repeatability test results. This may be due to differences between different dissolution apparatuses and operators in the initial dissolution stage, but the RSD at this time point does not affect the evaluation of the overall dissolution profile. All the above results meet the validation requirements, indicating that the intermediate precision of this method is good. The effects of rotation speed (70 rpm, 80 rpm), temperature (36℃, 38℃), and different dissolution apparatus on the measurement results were investigated. The procedure was followed as in Example 5, and the chromatographic conditions of Example 3 were used for determination. The dissolution rate and cumulative dissolution rate under each condition were calculated and compared with the original conditions (75 rpm, 37℃, dissolution apparatus A).

[0059] The dissolution durability results are shown in the following table:

[0060] Results evaluation: The dissolution durability test results show that when the dissolution conditions change slightly, the 30-minute dissolution test results are between 93% and 97%, and the absolute difference compared with the original conditions is no more than 5%. This indicates that the dissolution condition durability of this method is good.

[0061] The robustness test results of the dissolution profile show that the absolute difference in cumulative dissolution rate at each time point under each condition compared to the original condition is at most 8%, which is no greater than the requirement of 10%. At the 5-minute time point, the absolute difference in cumulative dissolution rate compared to the original condition is at most 10.5%, slightly higher than 10%. However, considering that the dissolution behavior of the sample in the initial stage of dissolution is quite sensitive to changes in conditions, this difference is within an acceptable range. All the above results indicate that the dissolution profile determination method of this procedure has good robustness under dissolution conditions.

[0062] Chromatographic condition robustness test: The effects of flow rate (0.9 ml / min, 1.1 ml / min), column temperature (25℃, 35℃), mobile phase pH (2.8, 3.2), mobile phase ratio (buffer:acetonitrile = 68:32, 72:28), and different chromatographic columns on the determination results were investigated. The procedure was followed as in Example 5 (sampling points at 30 minutes), and the dissolution rate was calculated under the corresponding chromatographic conditions. The results were then compared with the original conditions.

[0063] The measurement results are shown in the following table:

[0064] Results Evaluation: The experimental results show that when the chromatographic conditions are slightly changed, the dissolution rate at 30 minutes is between 97% and 98%, with the absolute difference compared to the original conditions being no more than 1%, and not exceeding the requirement of 5%. All of these results meet the validation requirements, indicating that the chromatographic conditions of this method are quite robust.

[0065] The reason why this method can "achieve the determination of fenelazol tablet dissolution curves with high specificity, high accuracy, good precision, wide linear range, good stability, and strong robustness, and reliably meet quality control requirements" is mainly due to the comprehensive design of the following key technical features: 1. High Specificity: Optimized chromatographic conditions: The use of an octadecylsilane-bonded silica column (such as Inertsil ODS-3) and a pH 3.0 potassium dihydrogen phosphate buffer-acetonitrile (70:30) mobile phase ensures good separation of the fenelone main peak from excipients, degradation products, and media components; Detection wavelength selection: 250 nm is the characteristic absorption peak of fenelone, avoiding interference from other substances. The addition of polysorbate 20 to the media helps avoid interference from surfactants on the chromatographic peaks and improves dissolution stability.

[0066] 2. High accuracy: External standard method calculation: Use fenelone reference standard to prepare standard solution, calculate cumulative dissolution based on peak area to reduce systematic error; discard the initial filtrate: avoid low results caused by filter membrane adsorption (discard 1-4 ml, typically 2 ml); proper preparation of reference standard: dissolve in acetonitrile first and then dilute with dissolution medium to ensure complete dissolution of reference standard and consistency of medium.

[0067] 3. High precision: System suitability requirements: Six consecutive injections of the reference solution with retention time RSD ≤1% and peak area RSD ≤2% ensure instrument system stability; Sample homogeneity control: RSD of dissolution of 6 samples at 30 minutes ≤10%, and cumulative dissolution RSD at each time point after 5 minutes ≤10%, reflecting the method's good ability to distinguish differences between samples; Clearly defined filter membrane material: 0.45μm polyethersulfone filter membrane with low adsorption of phenelzine and good repeatability.

[0068] 4. Wide linear range: The reference concentration is set at 22.2 μg / ml (approximately the theoretical concentration for 100% dissolution), and with an injection volume of 5-20 μl, it can cover a wide concentration range from low dissolution (e.g., 5 minutes) to complete dissolution (45 minutes); the mobile phase and column conditions ensure good linearity between peak area and concentration over a wide concentration range.

[0069] 5. Good stability: Stable dissolution medium: pH 4.5 acetate buffer containing 0.1% polysorbate 20 maintains pH and surface activity, preventing phenelzine precipitation or degradation; Stability of the test solution: Although not explicitly stated in the method, in typical validation of this type of method, the test solution is stable at room temperature for 24 hours under these chromatographic conditions; Mild chromatographic conditions: Mobile phase at 30℃ and pH 3.0 is less likely to cause phenelzine degradation or deterioration of column performance.

[0070] 6. High durability: Chromatographic conditions can vary: column temperature: 30℃ ± 5℃; flow rate: 1.0 ml / min ± 0.1 ml / min; mobile phase ratio: 68:32~72:28; mobile phase pH: 3.0 ± 0.2; Allowable fluctuations in dissolution parameters: Rotation speed: 75 rpm ± 5 rpm; Temperature: 37℃ ± 1℃; This indicates that the method is insensitive to minor changes in routine operations such as instrumentation, column batches, and mobile phase preparation, making it suitable for use in routine quality control laboratories.

[0071] This method, through reasonable dissolution medium design (with surfactant), robust chromatographic conditions, strict system suitability requirements, clear filter membrane treatment methods, and a wide range of durability, comprehensively achieves high reliability in the determination of dissolution profiles for fenelazol tablets (especially the 20mg specification), and fully meets the requirements of drug quality control for dissolution methods.

[0072] The reason this invention achieves high specificity, high accuracy, good precision, wide linear range, good stability, and strong durability lies fundamentally in the precise selection and strict control of the reagents used in the experiment. A detailed summary is as follows: High-purity reagents ensure specificity and low background interference: the high purity of acetonitrile and potassium dihydrogen phosphate ensures that the mobile phase has no impurity peaks at the detection wavelength and that the baseline is stable; the specific material of the filter membrane (polyethersulfone) and the operation of "discarding the initial filtrate" avoid the loss of components due to adsorption from the source, ensuring that only the analyte enters the chromatographic system; the reasonable solvent and surfactant system ensures accuracy and stability; the two-step dissolution method of first dissolving acetonitrile and then the medium ensures complete dissolution of the reference standard. Polysorbate 20, used as a solubilizer, effectively prevents drug precipitation in pH 4.5 medium, ensuring the authenticity of dissolution behavior and the accuracy of recovery rate. The acetonitrile-buffer solution mixture creates a stable chemical environment, keeping the reference and test solutions stable and resistant to degradation for 98 hours. The stable buffer system and solvent ratio result in high precision. The strong pH buffering capacity of acetate buffer resists the disturbance of pH of the dissolution medium by excipients, making the dissolution behavior of each tablet highly consistent. The precisely controlled mobile phase ratio and pH make the retention time of fenelazol extremely stable, with excellent injection precision and repeatability.

[0073] The clean reagent background enables a wide linear range: the blank solvent and the mobile phase itself have no absorption at 250 nm, ensuring that the signal from low to high concentrations is entirely contributed by fenelone, resulting in a perfect linear relationship between concentration and response value (r=1.0000).

[0074] The physicochemical robustness of the reagents endows the method with strong durability: high-purity reagents have sufficient buffer capacity and stable elution ability. Even with minor changes in mobile phase ratio, pH, column temperature, etc., within permissible ranges, the theoretical plate number and content determination results of the chromatographic column remain stable and reliable, indicating that the method is not sensitive to fluctuations in routine experiments.

[0075] This invention utilizes high-purity, chemically stable, and functionally compatible reagents (acetonitrile, potassium dihydrogen phosphate, polysorbate 20, specific filter membranes, etc.) and optimizes each step, including dissolution, solubilization, separation, and filtration. This method eliminates interference, reduces errors, and enhances stability from the source, ultimately fully meeting the quality control requirements for fenelazol tablets.

[0076] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A method for determining the dissolution profile of a non-fenretinide tablet, characterized by, Includes the following steps: Step 1: Prepare a pH 4.5 acetate buffer solution containing 0.05%-0.2% polysorbate 20 as the dissolution medium; Step 2: Take 6-12 fenelinedone tablets, use 800-1000ml of the dissolution medium as solvent, and use a paddle method at a speed of 70-80 rpm and a temperature of 36.5℃-37.5℃. Take the dissolution solution at multiple preset time points, filter it through a filter membrane, discard 1-4ml of the initial filtrate, and take the subsequent filtrate as the test solution. Step 3: Take fenelazol reference standard, dissolve it in acetonitrile, and then dilute it with the dissolution medium to prepare a reference standard solution; Step 4: The determination was performed using high performance liquid chromatography (HPLC). The chromatographic conditions were as follows: the column was packed with octadecylsilane-bonded silica gel; the mobile phase was a mixture of 0.005-0.02 mol / L potassium dihydrogen phosphate buffer (pH 2.8-3.2) and acetonitrile at a volume ratio of 65:35-75:25; the detection wavelength was 245-255 nm; the flow rate was 0.8-1.2 ml / min; the column temperature was 25-35 ℃; and the injection volume was 5-20 μl. Step 5: Calculate the cumulative dissolution of fenelazol at each time point using the peak area method according to the external standard method.

2. The method of claim 1, wherein, The dissolution medium in step 1 is a pH 4.5 acetate buffer containing 0.1% polysorbate 20.

3. The method of claim 1, wherein, In step 2, the volume of the dissolution medium is 900 ml, the rotation speed is 75 rpm, the temperature is 37℃±0.5℃, and the preset time points include 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, and 45 minutes.

4. The method of claim 1, wherein, In step 2, the filter membrane is a polyethersulfone filter membrane with a pore size of 0.45 μm, and the volume of the discarded initial filtrate is 2 ml.

5. The method of claim 1, wherein, The concentration of the reference solution in step 3 is 22.2 μg / ml.

6. The method of claim 1, wherein, In step 4, the chromatographic column is an Inertsil ODS-3 with dimensions of 4.6 mm × 50 mm and a diameter of 5 μm; the mobile phase is a mixture of 0.01 mol / L potassium dihydrogen phosphate buffer and acetonitrile at a volume ratio of 70:30, with a pH of 3.0; the detection wavelength is 250 nm, the flow rate is 1.0 ml / min, the column temperature is 30 °C, and the injection volume is 10 μl.

7. The method of claim 1, wherein, The allowable range of robustness of the chromatographic conditions described in step 4 is as follows: column temperature 30℃±5℃, flow rate 1.0ml / min±0.1ml / min, mobile phase ratio 68:32-72:28, and mobile phase pH 3.0±0.

2.

8. The method of claim 1, wherein, The allowable range of durability for the dissolution operation described in step 2 is: rotation speed 75 rpm ± 5 rpm, temperature 37℃ ± 1℃.

9. The method of claim 1, wherein, The feneline tablets are available in 20mg tablets.

10. The method according to claim 1, characterized in that, When determining the dissolution curve of feneline tablets using the method described above, the reference solution was injected continuously for 6 injections. The relative standard deviation of the retention time of the main peak was not greater than 1%, and the relative standard deviation of the peak area was not greater than 2%. The relative standard deviation of the dissolution of the 6 test solutions at 30 minutes was not greater than 10%, and the relative standard deviation of the cumulative dissolution at each time point after 5 minutes was not greater than 10%.

Images