Method for determining content of di-n-propylamine impurity in probenecid sodium
The separation and determination of dinpropylamine impurities in probenecid sodium through gas chromatography solves the shortcomings of the detection methods in the prior art, achieves the detection effect of high-specificity and sensitivity, and ensures the quality and safety of the drug.
Patent Information
- Application Number
- CN202510810920.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-17
- Publication Date
- 2025-08-15
AI Technical Summary
There is a lack of effective detection methods in the prior art to determine the content of di-n-propylamine impurities in probenecid sodium, which affects drug quality control and drug safety.
Using gas chromatography, HP-5 weak polar capillary chromatography column and dimethyl sulfoxide were used as diluents, combined with the gradient heating program, dinpropylamine impurities in probenecis sodium were separated and measured, and their content was calculated by external standard method.
It has achieved high-specificity, high sensitivity, good linearity and high accuracy detection of di-propylamine impurities, meeting the requirements of drug quality control and evaluation.
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Figure CN120490343A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for determining the content of di-n-propylamine impurities in probenecid sodium, and belongs to the field of drug quality detection. Technical Background
[0002] The synthesis of probenecid sodium involves the oxidation of the starting material p-toluenesulfonamide with potassium permanganate in the presence of sodium hydroxide to form p-carboxybenzenesulfonamide; alkylation of p-carboxybenzenesulfonamide with 1-bromopropane as an alkylating agent to form probenecid; and neutralization of probenecid with sodium hydroxide to form probenecid sodium. Dipropylamine is a degradation impurity in the synthetic API probenecid sodium. According to the ICHQ3A impurity guidance for new APIs, degradation impurities must be studied and controlled. Impurity detection methods are important parameters for drug quality control and safety assessment. Such methods must undergo methodological validation and meet specificity, linearity, and accuracy requirements to ensure the reliability and accuracy of impurity detection results.
[0003] Currently, there is no reported effective detection method for di-n-propylamine impurities. Therefore, in order to better detect di-n-propylamine impurities and ensure the safety and efficacy of probenecid sodium, it is necessary to establish a di-n-propylamine impurity detection method, which is of great significance to the quality control of probenecid sodium API. Summary of the Invention
[0004] The present invention aims to provide a method for determining the content of di-n-propylamine impurity in probenecid sodium, which has good detection capability and meets the separation requirements. The determination method is validated and the impurities are well separated. The method also has good specificity, sensitivity, linearity, recovery rate, durability and solution stability.
[0005] To achieve the above object, the technical solution of the present invention is achieved as follows: a method for determining the content of di-n-propylamine impurity in probenecid sodium, wherein the di-n-propylamine impurity is determined by gas chromatography, and the method is characterized in that the method comprises the following steps: 1) Prepare blank solution Accurately measure 2.0 ml of dimethyl sulfoxide, place it in an empty bottle, and shake well; 2) Preparation of reference solution Weigh an appropriate amount of dipropylamine reference substance accurately, add dimethyl sulfoxide to dilute to a solution containing 0.15 mg of dipropylamine per 1 ml, accurately measure 2.0 ml of this solution into a 20 ml headspace bottle, seal with a pressure cap, and shake to dissolve. This is used as the reference solution; 3) Prepare sample solution Take about 0.2g of the test sample, weigh it accurately, put it into an empty bottle, then add 2.0ml of dimethyl sulfoxide solution accurately, and seal it with a cap; 4) Chromatographic conditions Chromatographic column: HP-5 (30m*0.32mm*0.25µm), column temperature: 95°C, hold for 10 minutes, then increase to 200°C at a rate of 40°C / min, hold for 5 minutes; injection port temperature: 200°C; detector (FID) temperature: 250°C; carrier gas: N2, flow rate: 0.4ml / min; split ratio: 50:1; heating oven: 90°C; sample vial equilibration time: 30 minutes; 5) System suitability requirements The blank solvent does not interfere with the peaks of the components to be tested; a linear regression is performed using the concentration of di-n-propylamine to be tested corresponding to the peak area, and the linear correlation coefficient r should be no less than 0.995; 6) Determination method Accurately measure the blank, reference solution and test solution, determine according to the above chromatographic conditions, inject them into the gas chromatograph respectively, record the chromatogram, if the impurity peak is obvious in the chromatogram of the test solution, its content is calculated according to the external standard method; Standard limit: Calculated by external standard method, the di-n-propylamine impurity shall not exceed 0.15%.
[0006] During the gas chromatography analysis and detection process, the sample is diluted with a diluent and then injected, and the diluent is dimethyl sulfoxide; the injection volume of the sample is 1 ml, wherein the concentration of the probenecid sodium is 200 mg / mL.
[0007] The headspace injection conditions are as follows: heating box: 90°C; sample bottle equilibration time: 30 minutes.
[0008] The specification of the weak polarity capillary chromatographic column is: HP-5 (30m*0.32mm*0.25µm).
[0009] The gas chromatography analysis method is used in detecting or separating dipropylamine impurities in probenecid sodium.
[0010] The present invention provides a gas chromatography method for determining the content of di-n-propylamine impurities in probenecid sodium. Using a weakly polar chromatographic column HP-5 (30 m x 0.32 mm x 0.25 µm), dimethyl sulfoxide (DMSO) is selected as the diluent, and a gradient temperature ramp procedure is employed to effectively separate the di-n-propylamine impurity. Furthermore, the method exhibits strong specificity, high sensitivity, good linearity, and accuracy, demonstrating feasibility and practicality, providing a reference for product impurity determination. Furthermore, the method is easily disseminated and applied, and is of great significance for product quality control and evaluation. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 This is a diagram of the blank solution of di-n-propylamine.
[0012] Figure 2 This is the system suitability spectrum of di-n-propylamine.
[0013] Figure 3 This is the quantification limit spectrum of di-n-propylamine. DETAILED DESCRIPTION
[0014] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and Examples. The embodiments described below are only used to explain the present invention and are not to be construed as limiting the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents used or instruments that do not indicate manufacturers are conventional products that can be obtained commercially.
[0015] The method for measuring the content of di-n-propylamine in probenecid sodium is described in detail below according to an embodiment of the present invention, and the specific steps are as follows: Step (1): Prepare blank solution Accurately measure 2.0 ml of dimethyl sulfoxide into an empty bottle, shake well, and seal with a cap as the blank solution; Step (2): Preparation of reference solution Weigh an appropriate amount of dipropylamine reference substance accurately, add dimethyl sulfoxide to dilute to a solution containing 0.15 mg of dipropylamine per 1 ml, accurately measure 2.0 ml of this solution into a 20 ml headspace bottle, seal with a pressure cap, and use as the reference solution; Step (3): Prepare the sample solution to be tested Weigh approximately 200 mg of the probenecid sodium test sample accurately, and accurately measure 2.0 ml of dimethyl sulfoxide into a 20 ml headspace bottle, seal it with a pressure cap, and shake to dissolve to prepare the sample solution. Step (4) mainly collects the di-n-propylamine impurity peak In this step, the sample was collected by gas chromatography using an HP-5 column (30 m*0.32 mm*0.25 µm) at 95°C for 10 minutes, then at a heating rate of 40°C / min to 200°C, where it was maintained for 5 minutes. The sample was then injected into the sample inlet at 200°C and the detector (FID) at 250°C. The sample was then collected using N2 at a flow rate of 0.4 ml / min. The split ratio was 50:1, and the oven was set at 90°C. The sample vial equilibration time was 30 minutes. The chromatographic conditions in the detection step can significantly affect the accuracy of the detected di-n-propylamine content. The above chromatographic conditions significantly improve the accuracy of the measured di-n-propylamine content.
[0016] During the gas chromatography analysis and detection process, the sample is diluted with a diluent and then injected, and the diluent is dimethyl sulfoxide; the injection volume of the sample is 1 ml, wherein the concentration of the probenecid sodium is 200 mg / mL.
[0017] The headspace injection conditions are as follows: heating box: 90°C; sample bottle equilibration time: 30 minutes.
[0018] The specification of the weak polarity capillary chromatographic column is: HP-5 (30m*0.32mm*0.25µm).
[0019] The gas chromatography analysis method is used in detecting or separating dipropylamine impurities in probenecid sodium.
[0020] The present invention will be described below with reference to specific implementations. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.
[0021] Example 1 Specificity and system applicability Blank solution: Accurately measure 2.0 ml of dimethyl sulfoxide and place it in a 20 ml headspace bottle as the blank solution.
[0022] Reference solution (system suitability solution): Weigh an appropriate amount of di-n-propylamine accurately, add dimethyl sulfoxide to dilute it to a solution containing 0.15 mg of di-n-propylamine per 1 ml. Accurately measure 2.0 ml of this solution and place it in a 20 ml headspace bottle as the reference solution.
[0023] According to the above chromatographic conditions, blank solution and 6-pronged reference solution were injected into the gas chromatograph respectively. The blank solvent did not interfere with the peak of dipropylamine; the separation degree of dipropylamine was greater than 1.5; the RSD of the peak area of 6-pronged reference solution was 3.7%, less than 10.0%; all met the requirements. Figures 1 and 2 .
[0024] Example 2 Quantitation limit and detection limit
[0025] Accurately weigh an appropriate amount of dipropylamine, dissolve it in a diluent, and dilute it to a solution of appropriate concentration. Dilute it step by step, accurately measure 1 ml and inject it into the gas chromatograph. Record the chromatogram. When the signal-to-noise ratio (S / N) is about 3:1, it is the detection limit. When the signal-to-noise ratio (S / N) is about 10:1, it is the quantification limit. Take the quantification limit solution and inject it 6 times continuously. Record the chromatogram. Figure 3 .
[0026] It can be seen from the data in the above table that the quantitative limit concentration of di-n-propylamine is equivalent to 0.0016% of the concentration of the test solution, and the detection limit concentration is equivalent to 0.0008% of the concentration of the test solution, which is less than the reporting limit (0.05%) and meets the detection requirements.
[0027] Example 3 Linearity and Range
[0028] Determination of di-n-propylamine standard curve
[0029] Linear solution: Weigh an appropriate amount of di-n-propylamine accurately, add dimethyl sulfoxide to dilute to a stock solution containing 1.5 mg of dipropylamine per 1 ml. Then accurately measure an appropriate amount of the stock solution and dilute with dimethyl sulfoxide solution to solutions containing 0.016 mg (limit of quantitation), 0.075 mg, 0.15 mg, 0.22 mg and 0.30 mg of di-n-propylamine per 1 ml, respectively, as a linear series solution.
[0030] Accurately measure 2.0 ml of each linear series solution into a 20 ml headspace vial, seal with a cap, and shake to dissolve to obtain linear solutions 1 to 5. Accurately measure 1 ml of each linear solution and inject it into a gas chromatograph, record the chromatogram, and examine its linearity.
[0031] The concentration of dipropylamine in the range of 0.0016~0.2964mg / ml showed a significant linear relationship with the peak response value, r=0.9979, r≥0.995, and the intercept of the linear regression line was equivalent to -1.39 of the limit concentration response value, which met the verification requirements and had a good linear relationship.
[0032]
[0033] Example 4 Accuracy
[0034] Solution preparation
[0035] Linear stock solution: Weigh an appropriate amount of di-n-propylamine accurately, add dimethyl sulfoxide to dilute it into a stock solution containing 1.5 mg of di-n-propylamine per 1 ml, which is used as the linear stock solution.
[0036] 0.008% limit solution: Take 200 mg of the test sample, accurately weigh it, and place it in a 20 ml headspace bottle. Then accurately measure 2.0 ml of linear solution 1, seal it with a pressure cap, shake to dissolve, and prepare 3 parallel portions.
[0037] 0.15% limit solution: Take 200 mg of the test sample, accurately weigh it, and place it in a 20 ml headspace bottle. Then accurately measure 2.0 ml of linear 3 solution, seal it with a cap, shake it to dissolve, and prepare three parallel portions.
[0038] 0.23% limit solution: Take 200 mg of the test sample, accurately weigh it, and place it in a 20 ml headspace bottle. Then accurately measure 2.0 ml of linear 4 solution, seal it with a pressure cap, shake it to dissolve, and prepare three parallel portions.
[0039] At three concentrations, the recoveries of 9 portions of di-n-propylamine ranged from 93.7% to 110.1%, with an RSD of 6.0%. The RSD was less than 10.0%, indicating good accuracy of the method.
[0040]
[0041] Example 5 Solution stability test
[0042] The newly prepared test solution was left at room temperature for 24 hours. Samples were then injected and measured, and the RSD of the dipropylamine peak area was calculated. The results showed that after 24 hours at room temperature, the RSD of the dipropylamine peak area in the test solution was 3.4%, and the RSD was no greater than 10.0%, meeting the requirement. This preliminarily indicates that the test solution was stable within 24 hours.
[0043] Example 6 Sample determination
[0044] Take three batches of probenecid sodium and, according to the above chromatographic conditions, accurately measure 2 ml each of blank, reference solution, and test solution, inject them separately, and record the chromatogram. If di-n-propylamine is detected in the chromatogram of the test solution, calculate the di-n-propylamine content by the external standard method. The determination results of each batch of samples are shown in the following table:
[0045] Those skilled in the art will readily understand that the above embodiments are merely exemplary and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to fall within the scope of protection of the present invention.
Claims
1. A method for measuring the impurity content of di-n-propylamine in probenecid sodium, characterized in that: The di-n-propylamine impurity is detected by gas chromatography; the chromatographic conditions include the following steps: (1) Preparation of blank solution Accurately measure 2.0 ml of dimethyl sulfoxide, place it in an empty bottle, and shake well; (2) Preparation of control solution Weigh an appropriate amount of di-n-propylamine reference substance accurately, add dimethyl sulfoxide to dilute to a solution containing 0.15 mg of di-n-propylamine per 1 ml, accurately measure 2.0 ml of this solution into a 20 ml headspace bottle, seal with a pressure cap, and shake to dissolve. This is used as the reference solution; (3) Preparation of test solution Take about 0.2g of the test sample, weigh it accurately, put it into an empty bottle, then accurately add 2.0ml of dimethyl sulfoxide solution, press the cap and seal it as the test solution; (4) Chromatographic conditions Use a weak polar capillary column as the chromatographic column; Carrier gas: N2 Split ratio 50:1 The flow rate is 0.4 ml per minute; Detector: FID The detector temperature was 250°C; Inlet temperature: 200°C; Method of operation: headspace injection Gradient temperature program: start column temperature at 95°C, maintain for 10 minutes, increase to 200°C at a rate of 40°C / min, and maintain for 5 minutes; Determination method: Accurately measure the test solution and reference solution, determine according to the above chromatographic conditions, inject them into the gas chromatograph respectively, and record the chromatogram. If there is an impurity peak in the chromatogram of the test solution, calculate the peak area according to the external standard method. The di-n-propylamine impurity shall not exceed 0.15%. The reporting limit is 0.05%.
2. a method for measuring di-n-propylamine impurity content in probenecid sodium according to claim 1, characterized in that During the gas chromatography analysis and detection process, the sample is diluted with a diluent and then injected, and the diluent is dimethyl sulfoxide; the injection volume of the sample is 1 ml, wherein the concentration of the probenecid sodium is 200 mg / mL.
3. a method for measuring di-n-propylamine impurity content in probenecid sodium according to claim 1, characterized in that The headspace injection conditions are as follows: heating box: 90°C; sample bottle equilibration time: 30 minutes.
4. a method for measuring di-n-propylamine impurity content in probenecid sodium according to claim 1, characterized in that The specification of the weak polarity capillary chromatographic column is: HP-5 (30m*0.32mm*0.25µm).
5. a method for measuring the di-n-propylamine impurity content in probenecid sodium according to claim 1, characterized in that The gas chromatography analysis method is used in detecting or separating dipropylamine impurities in probenecid sodium.