Condensed impurity in carlevodopa sustained release tablet and detection method thereof

Abstract

The invention belongs to the technical field of medicine detection, and particularly relates to condensed impurities in carlevodopa sustained release tablets and a detection method of the condensed impurities. The invention provides a condensed impurity in a carlevodopa sustained-release tablet, the molecular formula of the condensed impurity is C19H20N2O7, and the structure of the condensed impurity is as shown in formula I in the specification. The invention also provides a detection method of the condensed impurity. The condensed impurity in the carlevodopa sustained release tablet is accurately detected by adopting a liquid chromatography. The detection method can realize effective separation of carbidopa from condensed impurities and other degraded impurities and main components, and has good specificity, sensitivity and accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of drug detection, and in particular relates to condensed impurities in carbodiol sustained-release tablets and a detection method thereof. Background Art

[0002] Carbidopa is a combination of levodopa and carbidopa, first developed and marketed by Merck Pharmaceuticals Co., Ltd. The imported original preparation is called "Xinning", and is one of the main drugs for relieving and treating Parkinson's symptoms. After levodopa and carbidopa are used together, a small dose of levodopa can reach an effective brain dopamine concentration, thereby improving Parkinson's disease symptoms such as rigidity, bradykinesia, balance disorders and tremors.

[0003] The raw material carbidopa in the carbidopa sustained-release tablets will produce different degradation impurities during storage, and these degradation impurities will further undergo condensation reactions with the raw material carbidopa to generate new impurities. These new impurities may aggravate the side effects of the carbidopa sustained-release tablets and affect the efficacy of the drug, such as causing dyskinesia (an abnormal involuntary movement), nausea, hallucinations, mental confusion, dizziness, chorea and dry mouth, which will have an adverse effect on the safety of the drug. However, no relevant reports on condensation impurities in the carbidopa sustained-release tablets have been found so far. Summary of the invention

[0004] In view of this, the present invention provides a condensed impurity in a carbidopa sustained-release tablet and a detection method thereof. The detection method can detect the condensed impurity as shown in Formula I in the carbidopa sustained-release tablet, realize the effective separation of carbidopa from the condensed impurity and other degradation impurities and the main component, and has good specificity, sensitivity and accuracy.

[0005] In order to solve the above technical problems, the first aspect of the present invention provides a condensed impurity in a carbendazim sustained-release tablet, wherein the molecular formula of the condensed impurity is C 19 H 20 N 2 O 7 , the structure is shown in Formula I:

[0006]

[0007] The inventors found during the research that carbidopa, a component of carbidopa sustained-release tablets, is prone to produce a variety of degradation impurities during storage, and these degradation impurities may undergo condensation reactions with carbidopa. After a large number of experiments, the inventors identified a condensation impurity from the carbidopa sustained-release tablets. The chemical structure of the condensation impurity was confirmed by nuclear magnetic hydrogen spectrum as shown in Formula I, and the chemical name is (R, Z)-3-(3,4-dihydroxyphenyl)-2-(2-(1-(3,4-dihydroxyphenyl)-1-oxoprop-2-en-1-yl)hydrazine)-2-methylpropionic acid. According to the structural formula, it is speculated that the condensation impurity is formed by the condensation of carbidopa and its degradation impurities.

[0008] The second aspect of the present invention provides a method for detecting condensed impurities in the above-mentioned carbodiol sustained-release tablets, which is determined by high performance liquid chromatography, and the chromatographic conditions include:

[0009] Chromatographic column: C18 column;

[0010] Column temperature: 30±5℃;

[0011] Mobile phase A: phosphate buffer, pH 1.7-3.0;

[0012] Mobile phase B: a mixed solution of acetonitrile and methanol in a volume ratio of 1:1;

[0013] Flow rate: 0.8~1.2mL / min;

[0014] Detection wavelength: 270~290nm;

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

[0016] Time (minutes) Mobile phase A (%) Mobile phase B (%) 0 90～100 0～10 12 90～100 0～10 26 30 70 29 30 70 31 97 3 36 97 3

[0018] In combination with the second aspect, the specifications of the chromatographic column are 250×4.6 mm, 5 μm.

[0019] Preferably, the model of the chromatographic column may be Waters Symmetry C18, or may be other chromatographic columns with equivalent performance.

[0020] In combination with the second aspect, the pH value of the phosphate buffer is 2.1.

[0021] In combination with the second aspect, the phosphate buffer is prepared from sodium dihydrogen phosphate, phosphoric acid and water.

[0022] Preferably, 1.80 g of anhydrous sodium dihydrogen phosphate or 2.07 g of sodium dihydrogen phosphate is taken, 1000 mL of water is added to dissolve the mixture, and then the pH value is adjusted to 2.1 with phosphoric acid.

[0023] In combination with the second aspect, in the gradient elution, the initial ratio of mobile phase A to mobile phase B is 97:3.

[0024] In combination with the second aspect, the flow rate is 1.0 mL / min, and the detection wavelength is 275-285 nm, preferably 280 nm.

[0025] In conjunction with the second aspect, the injection volume during sample detection is 20 μL.

[0026] In conjunction with the second aspect, the method for detecting condensed impurities in the card-levodopa sustained-release tablets comprises the following steps:

[0027] Prepare a blank solution, a series of reference solutions of the condensed impurities and a test solution of Carbendazim sustained-release tablets;

[0028] The blank solution, the series of reference solutions of the condensed impurities and the test solution are tested respectively by the high performance liquid chromatography method;

[0029] A standard curve of the reference substance is drawn, and the content of the condensed impurity in the test solution is determined by the corresponding standard curve.

[0030] In combination with the second aspect, the blank solution, series of reference solutions and test solution are all prepared using 0.05-0.2 mol / L hydrochloric acid solution.

[0031] The third aspect of the present invention provides an application of the above detection method in the quality control of carboplatin sustained-release tablets.

[0032] Beneficial effects obtained by the present invention: The present invention identifies a condensation impurity in a card-left double dopa sustained-release tablet and provides a method for detecting the impurity. The detection method can effectively separate the condensation impurity from other degradation impurities and achieve accurate quantification, and the method has good specificity, high sensitivity (detection limit as low as 0.012 μg / mL), good linear relationship (correlation coefficient r=0.9999), good accuracy (recovery rate is within the range of 90% to 115%), good repeatability (RSD is less than 10%) and good durability, and can meet the detection requirements of the condensation impurity, providing a new guarantee for the quality control of the card-left double dopa sustained-release tablet. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a hydrogen nuclear magnetic resonance spectrum of the condensed impurity shown in formula I;

[0034] Figure 2 is the structural formula of the condensed impurity as shown in Formula I with the positions of each hydrogen atom marked;

[0035] Figure 3 is the liquid chromatogram of the blank solution;

[0036] Figure 4 is the liquid chromatogram of the condensed impurity reference solution;

[0037] Figure 5 It is the liquid chromatogram of the test sample plus the reference solution. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] The inventor discovered a condensation impurity in the study of the stability of carbidopa sustained-release tablets. The condensation impurity is a condensation impurity formed by the condensation of carbidopa in carbidopa and a degradation product of carbidopa. The condensation impurity may aggravate the side effects of carbidopa sustained-release tablets and affect the efficacy of the drug. To this end, the present invention provides a detection method for the condensation impurity, which realizes the effective separation of the condensation impurity from other degradation impurities and the main component, and further provides guarantee for the quality control of carbidopa sustained-release tablets.

[0040] The condensed impurities and the detection method of the present invention are described below through specific examples.

[0041] The condensation impurity reference substance used in the present invention was purchased from Jiangxi Yehong Technology Co., Ltd., batch number: YH40605; the test substance carbidopa sustained-release tablets were purchased from MSD Pharma (Singapore) Pte. Ltd., and the other reagents used were all commonly used commercial preparations.

[0042] Example 1

[0043] This embodiment provides a condensed impurity in a carbodiol sustained-release tablet, the molecular formula of which is C 19 H 20 N 2 O 7 , molecular weight is 388.38, structural formula is shown in formula Ⅰ:

[0044]

[0045] Its nuclear magnetic resonance hydrogen spectrum is as follows Figure 1 The positions of the hydrogen atoms are shown in Figure 2 The corresponding chemical shift information of specific hydrogen atoms is shown in Table 1.

[0046] Table 1

[0047]

[0048] Example 2

[0049] This embodiment provides a method for detecting condensed impurities in the carboplatin sustained-release tablets in Embodiment 1, the steps comprising:

[0050] (1) Solution preparation:

[0051] Preparation of blank solution: Take blank auxiliary materials prepared according to the prescription ratio but not containing the main components (levodopa and carbidopa), add 0.1 mol / L hydrochloric acid solution to dissolve and disperse, shake well, and filter.

[0052] Preparation of test solution: Weigh an appropriate amount of ground fine powder of carbidopa sustained-release tablets, dissolve it in 0.1 mol / L hydrochloric acid solution and quantitatively dilute it into a mixed solution containing approximately 1 mg of carbidopa per 1 mL, filter it, and take the filtrate for use.

[0053] Preparation of reference stock solution: Accurately weigh an appropriate amount of condensation impurity reference, dissolve it in 0.1 mol / L hydrochloric acid solution and quantitatively dilute it to make a solution containing approximately 0.2 mg per 1 mL.

[0054] Preparation of reference substance solution: Accurately measure an appropriate amount of reference substance stock solution and quantitatively dilute it with 0.1 mol / L hydrochloric acid solution to make a solution containing approximately 2 μg per 1 mL.

[0055] Preparation of test sample plus reference solution: Weigh appropriate amounts of ground fine powder of carbidopa sustained-release tablets and condensed impurity reference substance respectively, accurately weigh them, dissolve them in 0.1 mol / L hydrochloric acid solution and quantitatively dilute them to make solutions containing approximately 1 mg of carbidopa and 2 μg of impurities per 1 mL, filter them, and take the filtrate for later use.

[0056] (2) Determination by high performance liquid chromatography, the specific chromatographic conditions include:

[0057] Chromatographic column: C18 column (Waters Symmetry C18), 250×4.6 mm, 5 μm (other chromatographic columns with equivalent performance may also be used);

[0058] Column temperature: 30°C;

[0059] Mobile phase A: phosphate buffer (pH = 2.1);

[0060] Mobile phase B: a mixed solution of acetonitrile and methanol (volume ratio 1:1);

[0061] Flow rate: 1.0 mL / min;

[0062] Injection volume: 20 μL;

[0063] Detection wavelength: 280nm.

[0064] Elution program: gradient elution, as shown in Table 2:

[0065] Table 2

[0066] Time (minutes) Mobile phase A (%) Mobile phase B (%) 0 97 3 12 97 3 26 30 70 29 30 70 31 97 3 36 97 3

[0067] Among them, the mobile phase A phosphate buffer can be prepared according to the following steps: take 1.80g of anhydrous sodium dihydrogen phosphate or 2.07g of sodium dihydrogen phosphate, add 1000mL of water to dissolve it, and adjust the pH value to 2.1 with phosphoric acid.

[0068] Test example

[0069] According to the detection conditions of Example 2 and using the solution prepared in Example 2, the detection method was investigated and verified in terms of specificity, linearity, sensitivity, accuracy, and durability. The specific detection process is as follows:

[0070] (I) Specificity test

[0071] The blank solution, reference solution and test solution plus reference solution prepared according to the method of Example 2 were measured respectively, and the test was performed under the conditions of the above-mentioned method, and the spectra were recorded. Figures 3 to 5 shown.

[0072] Depend on Figures 3 to 5 It can be seen that, by adopting the above-mentioned detection conditions provided by the present invention, the blank auxiliary material does not interfere with the detection of condensed impurities, the main components of the test sample and the condensed impurities can be well separated, and the separation degree between the condensed impurities and the adjacent impurities is 2.9, which all meet the requirements and have good method specificity.

[0073] (II) Detection limit and quantification limit test

[0074] Take the condensed impurity reference substance stock solution, perform gradient quantitative dilution in sequence, and perform detection according to the above detection method. The quantitative limit is when the peak height of the chromatographic peak is 10 times the baseline noise, and the detection limit is when the peak height of the chromatographic peak is 3 times the baseline noise. The detection limit and quantitative limit results are shown in Table 3.

[0075] Table 3

[0076]

[0077] (III) Linear relationship verification test

[0078] The condensed impurity reference substance stock solution was diluted to different concentrations in sequence to obtain a series of standard reference substance solutions, which were measured according to the above detection method. The concentration of the condensed impurity (μg / mL) was used as the abscissa and the corresponding peak area was used as the ordinate to draw a standard curve and calculate the regression equation. The results are shown in Table 4.

[0079] Table 4

[0080]

[0081]

[0082] It can be seen from Table 4 that the concentration of the above condensed impurities has a good linear relationship with the peak area, indicating that the detection method of condensed impurities provided by the present invention is capable of detecting the content of condensed impurities within this range.

[0083] (IV) Accuracy test

[0084] The limit solutions of condensed impurity limits of 20%, 100% and 150% were used as recovery test samples. The specific preparation process of the required solutions is as follows:

[0085] Accurately weigh about 308 mg of the carbidopa sustained-release tablets (containing about 50 mg of carbidopa), place them in a 50 mL volumetric bottle, weigh 9 portions in parallel, add appropriate amounts of solvent to dissolve them, then add appropriate amounts of condensation impurity reference stock solution, and prepare solutions with final impurity concentrations of 20%, 100% and 150% of the limit concentration, respectively. Prepare 3 portions in parallel for each concentration as the recovery test solution; at the same time, accurately measure an appropriate amount of condensation impurity reference stock solution, quantitatively dilute it with 0.1 mol / L hydrochloric acid solution to prepare a solution containing about 2 μg per 1 mL, as the corresponding recovery reference solution. Determinations were performed according to the above detection method, and the results are shown in Table 5. (Recovery (%) = (measured amount - background amount) / added amount × 100%).

[0086] Table 5

[0087]

[0088] As shown in Table 5, within the limit concentration range of 20% to 150%, the recovery rate of the condensed impurities was between 90% and 115%, and the RSD was 6.4%, which was less than 10%, indicating that the detection method had good accuracy.

[0089] (V) Repeatability test

[0090] Accurately weigh an appropriate amount of the test sample of the Carbidopa sustained-release tablets, prepare the test solution according to the method for preparing the test solution, repeat the preparation of 6 portions of the test solution and the reference solution of about 2 μg / mL, record them as 1 to 6, and perform the test according to the above detection method. The results are shown in Table 6.

[0091] Table 6

[0092]

[0093] It can be seen from Table 6 that the detection results of the 6 test solutions are basically consistent, and the relative standard deviation is less than 10%, indicating that the detection method provided by the present invention has good repeatability.

[0094] (VI) Durability test

[0095] The above test sample and reference solution were measured respectively, and the test was performed according to the following fine-tuning chromatographic conditions. The fine-tuning chromatographic conditions and test results are shown in Table 7.

[0096] Table 7

[0097] Durability Separation degree of condensed impurities and adjacent impurities Condensation impurity peak area Normal conditions 2.92 66445 Flow rate 0.8mL / min 1.45 82345 Flow rate: 1.2 mL / min 4.26 59133 Wavelength 275nm 2.93 57763 Wavelength 285nm 2.98 77415 Column temperature 35℃ 3.13 71323 Column temperature 25℃ 2.83 70329 Initial ratio of mobile phase: 95:5 2.54 68752 Initial ratio of mobile phase: 99:1 2.98 72586

[0098] It can be seen from Table 7 that after fine-tuning the chromatographic conditions, the separation degree between the condensed impurities and the adjacent impurities still meets the requirements, indicating that the detection method provided by the present invention has good durability.

[0099] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A condensed impurity in a carbocycline sustained-release tablet, characterized in that: The molecular formula of the condensed impurity is C 19 H 20 N2O7, the structure is shown in formula Ⅰ:

2. A method for detecting condensed impurities in the carbodiol sustained-release tablets according to claim 1, characterized in that: The HPLC method was used for determination. The chromatographic conditions included: Chromatographic column: C18 column; Column temperature: 30±5℃; Mobile phase A: phosphate buffer, pH 1.7-3.0; Mobile phase B: a mixed solution of acetonitrile and methanol in a volume ratio of 1:1; Flow rate: 0.8~1.2mL / min; Detection wavelength: 270~290nm; Elution program: Gradient elution, the elution program is as follows: 。 3. The method for detecting condensed impurities in the carbodiol sustained-release tablets according to claim 2, characterized in that: The specifications of the chromatographic column are 250×4.6 mm, 5 μm.

4. The method for detecting condensed impurities in the carbodiol sustained-release tablets according to claim 2, characterized in that: The pH value of the phosphate buffer is 2.

1.

5. The method for detecting condensed impurities in the carbodiol sustained-release tablets according to claim 4, characterized in that: The phosphate buffer is prepared from sodium dihydrogen phosphate, phosphoric acid and water.

6. The method for detecting condensed impurities in the carbodiol sustained-release tablets according to claim 2, characterized in that: In the gradient elution, the initial ratio of mobile phase A to mobile phase B was 97:

3.

7. The method for detecting condensed impurities in the carbodiol sustained-release tablets according to claim 2, characterized in that: The flow rate is 1.0 mL / min, and the detection wavelength is 275-285 nm.

8. The method for detecting condensed impurities in the carbodiol sustained-release tablets according to claim 2, characterized in that: The steps include: Prepare a blank solution, a series of reference solutions of the condensed impurities and a test solution of Carbendazim sustained-release tablets; The blank solution, the series of reference solutions of the condensed impurities and the test solution are tested respectively by the high performance liquid chromatography method; A standard curve of the reference substance is drawn, and the content of the condensed impurity in the test solution is determined by the corresponding standard curve.

9. The method for detecting condensed impurities in the carbodiol sustained-release tablets according to claim 8, characterized in that: The blank solution, reference solution and test solution are all prepared using 0.05-0.2 mol / L hydrochloric acid solution.

10. Use of the detection method according to any one of claims 2 to 9 in the quality control of carboplatin sustained-release tablets.

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