A method for detecting the particle size and particle size distribution of tofacitinib citrate bulk drug
By using wet laser diffraction combined with 0.1% span 80-n-hexane solution as a dispersant, the reproducibility and precision issues of particle size detection of tofacitinib citrate raw material were resolved, and stable particle size distribution detection was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- MAYINGLONG PHARMA GROUP
- Filing Date
- 2023-08-03
- Publication Date
- 2026-07-24
AI Technical Summary
Existing dry laser diffraction methods for particle size determination of tofacitinib citrate raw material have poor reproducibility, cannot obtain accurate data, and require large sample volumes. In wet methods, the dispersion system is unstable, the occlusion decreases rapidly, and the particle size cannot be accurately determined.
Wet laser diffraction was used with 0.1% Span 80-n-hexane solution as a dispersant. The sample was ultrasonically stirred until it was uniformly dispersed. The sample refractive index was set to 1.646, the sample absorbance to 0.01, and the dispersant refractive index to 1.38. The detection parameters were set to general mode, the number of measurements was 3, the sample test time was 10s, and the occlusion was controlled within the range of 8-20%.
It improves the reproducibility and precision of particle size and particle size distribution detection of tofacitinib citrate raw material, and the dispersion system has good stability, enabling accurate determination of particle size and particle size distribution.
Smart Images
Figure CN117030550B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of pharmaceutical analysis technology, specifically relating to a method for detecting the particle size and particle size distribution of tofacitinib citrate raw material. Background Technology
[0002] Tofacitinib citrate is an oral Janus kinase (JAK) inhibitor developed by Pfizer. It selectively inhibits JAK kinase, blocking the JAK / STAT pathway, thereby inhibiting cell signal transduction and related gene expression and activation. It is used to treat various immune diseases such as rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. The chemical name of tofacitinib citrate is (3R,4R)-4-methyl-3-(methyl-7H-pyrrolo[2,3-d]pyrimidin-4-ylamino)-β-oxo-1-piperidinium propionitrile citrate, and its specific chemical structure is as follows:
[0003]
[0004] Tofacitinib citrate tablets were first approved by the FDA in 2012, and the extended-release formulation was approved in 2016. It was the first JAK inhibitor to be administered orally once daily for the treatment of rheumatoid arthritis. The extended-release tablets offer the advantages of long-acting action and the once-daily dosing, which are beneficial for disease management. The particle size of the active pharmaceutical ingredient (API) is a key quality attribute affecting the quality and dissolution of solid dosage forms. Therefore, it is necessary to control the particle size of the tofacitinib citrate API, and this control process requires effective testing methods for particle size and particle size distribution.
[0005] The main particle size testing methods for active pharmaceutical ingredients (APIs) include microscopy, sieving, air spray sieving, and laser diffraction. Currently, laser diffraction is the most widely used method, which is further divided into dry laser diffraction and wet laser diffraction. In 2021, Mou Cong et al. disclosed a laser scattering method for determining the particle size of tofacitinib citrate API. Specifically, based on Method 3 of the General Chapters on Particle Size Determination in Part IV of the Pharmacopoeia of the People's Republic of China, they attempted to determine the particle size of tofacitinib citrate API using both wet and dry methods to select a suitable method. Tofacitinib citrate is slightly soluble in water, readily soluble in methanol, and almost insoluble in acetonitrile, acetone, and ethanol. When using the wet method to determine the particle size of tofacitinib citrate API, attempts were made to use purified water and ethanol of different concentrations as dispersants. All of these methods resulted in unstable dispersion systems and a rapid decrease in opacity, making accurate particle size determination impossible. Tofacitinib citrate raw material is non-hygroscopic, and the dry method for determination does not require pre-dispersing of the sample, making it simple and convenient. Therefore, the dry method was chosen as the method for determining the particle size of tofacitinib citrate raw material.
[0006] However, the applicant found in actual research that although dry laser diffraction is simpler than wet methods, the reproducibility of dry methods for determining the particle size of tofacitinib citrate API is poor, making it impossible to obtain accurate data, and the sample volume required for dry methods is also large. Therefore, there is an urgent need to develop a method for detecting the particle size and particle size distribution of tofacitinib citrate API with better reproducibility and precision.
[0007] Therefore, this invention is proposed. Summary of the Invention
[0008] To address the aforementioned technical problems, the present invention aims to provide a method for detecting the particle size and particle size distribution of tofacitinib citrate raw material. This method exhibits good reproducibility and precision, significantly improving the stability of the dispersion system and accurately detecting the particle size and particle size distribution of tofacitinib citrate raw material.
[0009] To achieve the above objectives, the present invention adopts the following technical solution:
[0010] A method for detecting the particle size and particle size distribution of tofacitinib citrate raw material includes the following steps: taking the tofacitinib citrate raw material to be tested, adding span 80-n-hexane solution as a dispersant, ultrasonically stirring until uniformly dispersed, and then detecting the obtained sample by wet laser diffraction.
[0011] Preferably, the concentration of Span 80 is 0.05–0.2 wt%; more preferably, it is 0.1 wt%.
[0012] Preferably, the ultrasonic stirring speed is 1500-2500 rpm and the stirring time is 30-300 s; more preferably, the ultrasonic stirring speed is 1800-2200 rpm and the stirring time is 50-70 s.
[0013] Preferably, the parameters for wet laser diffraction detection are set as follows: sample refractive index 1.6–1.8; sample absorbance 0.01–0.1; dispersant refractive index 1.3–1.4.
[0014] More preferably, the parameters for wet laser diffraction detection are set as follows: sample refractive index 1.646; sample absorbance 0.01; dispersant refractive index 1.38.
[0015] Preferably, the parameters for wet laser diffraction detection are set as follows: analysis mode is general mode, sensitivity is normal, number of measurements is 3, background measurement time is 10s, and sample testing time is 10s.
[0016] Preferably, in the wet laser diffraction detection process, D10, D50, and D90 are used as particle size distribution characteristic values.
[0017] Preferably, in wet laser diffraction detection, when the sample is added to the sample cell of the injector, the shading level is increased to the range of 8-20%.
[0018] Furthermore, this invention also seeks protection for the application of the above-described detection method in the preparation of tofacitinib citrate.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] This invention provides a method for detecting the particle size and particle size distribution of tofacitinib citrate raw material. The method uses wet laser diffraction and, through extensive experimental screening, a 0.1% span 80-n-hexane solution was selected as the dispersant to prepare a stable test suspension. This method solves the problem that when using conventional solvents as dispersants in the wet determination of tofacitinib citrate, the dispersion system becomes unstable, the light-blocking degree decreases rapidly, and the sample particle size cannot be accurately measured.
[0021] The detection process of this invention is simple and convenient, and the experimental results have good reproducibility and precision. It can be used for particle size testing in the production and use of tofacitinib citrate raw materials, providing an effective technical means for product quality control. Attached Figure Description
[0022] Figure 1 The particle size and particle size distribution of six samples were determined in parallel for Example 1.
[0023] Figure 2 This is a distribution chart of the intermediate precision test results for the second analyst in Example 2;
[0024] Figure 3 This is a comparison chart of the intermediate precision test results between the first and second analysts in Example 2;
[0025] Figure 4 The results are from the durability test at 1800 rpm in Example 3;
[0026] Figure 5 The results are from the durability test at 2200 rpm in Example 3;
[0027] Figure 6 The results of the durability test in Example 3 with an ultrasonic treatment time of 50 seconds are shown.
[0028] Figure 7 The results are from the durability test conducted in Example 3 with an ultrasonic treatment time of 70 seconds.
[0029] Figure 8 The results are from the solution stability test in Example 4. Detailed Implementation
[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0031] It should be noted that the instrument information in this embodiment of the invention is as follows: the laser particle size analyzer is a Malvern 3000 laser particle size analyzer.
[0032] Example 1
[0033] A method for detecting the particle size and particle size distribution of tofacitinib citrate raw material, comprising the following steps:
[0034] (1) Turn on the Malvern laser particle size analyzer, preheat for half an hour, and run the particle size testing software;
[0035] (2) Sample solution preparation: Weigh about 0.2g of the raw material of tofacitinib citrate to be tested, add 20mL of 0.1% span 80-n-hexane solution, stir and sonicate for 60s until evenly dispersed;
[0036] (3) Set the test parameters for the Malvern laser particle size analyzer:
[0037] The sample has a refractive index of 1.646;
[0038] The sample absorbance is 0.01.
[0039] The dispersant has a refractive index of 1.38;
[0040] The analysis mode is the general mode;
[0041] The background measurement time is 10 seconds.
[0042] The sample testing time is 10 seconds;
[0043] The measurement was performed 3 times;
[0044] The stirring speed is 2000 rpm;
[0045] (4) Sample injection and testing: After the instrument background test is completed, add the test sample into the sample cell of the injector, and add it to the range of 8% to 20% of the light shading. Measure six samples in parallel and compare the test results.
[0046] This invention uses particle size distribution characteristic values D(10), D(50), and D(90), and uses the relative standard deviation (RSD) of each particle size distribution characteristic value to characterize the particle size distribution range. The acceptable standards are shown in Table 1 below:
[0047] Table 1. Acceptable Standards for the Relative Standard Deviation of Particle Size Distribution Characteristic Values
[0048] Dx<10μm(n=6) ≤30％ ≤20％ ≤30％ Dx≥10μm(n=6) ≤15％ ≤10％ ≤15％
[0049] The test results for this embodiment are shown in Table 2 below:
[0050] Table 2 Test Results of Example 1
[0051]
[0052]
[0053] In the parallel determination of six samples, the particle size distribution (D(90)) was less than 40 μm, the particle size distribution (D(10)) was less than 10 μm, and the RSD of D(10) was 2.11%, less than 30%. The particle size distribution (D(50)) and particle size distribution (D(90)) were both greater than 10 μm, with the RSD of D(50) being 2.98%, less than 10%, and the RSD of D(90) being 3.10%, less than 15%. The particle size distribution and particle size distribution of the six parallel determinations are shown in the figure. Figure 1 From Table 1 above and Figure 1 It can be seen that the repeatability of the detection method of the present invention meets the acceptance criteria, and the method repeatability is good.
[0054] Example 2
[0055] To investigate the effect of random variations on precision, another analyst independently established a system to examine the precision of the determination method. Following the method described in Example 1, particle size analysis was performed on the same batch of samples on different dates by different operators, repeated six times. The results of the second analyst's six samples were compared with the results of the two analysts' twelve samples.
[0056] The results from the second analyst's 6 samples and the results from the two analysts' 12 samples need to meet the acceptance criteria shown in Table 1:
[0057] The results and conclusions are shown in Tables 3 and 4 below. Figure 2 :
[0058] Table 3 Results of the Intermediate Precision Test for the Second Analyst in Example 2 Table 3
[0059]
[0060] Table 4 Comparison of intermediate precision test results between the first and second analysts.
[0061]
[0062] Conclusion: For the six samples analyzed by the second analyst, D(90) was less than 40 μm, D(10) was less than 10 μm, and the RSD of D(10) was 2.41%, which is less than 30%. For the samples with D(50) and D(90) values, D(90) was greater than 10 μm, and the RSD of D(50) was 3.99%, which is less than 10%. The RSD of D(90) was 11.3%, which is less than 15%. The repeatability met the acceptance criteria.
[0063] The D(90) values of the 12 samples analyzed by different analysts on different dates were all less than 40 μm, the D(10) values were all less than 10 μm, the RSD of D(10) was 2.30%, less than 30%, the D(50) and D(90) values were all greater than 10 μm, the RSD of D(50) was 3.36%, less than 10%, and the RSD of D(90) was 8.36%, less than 15%. The repeatability met the acceptance criteria, and the method precision was good.
[0064] Example 3
[0065] Experiments with different parameters were conducted using rotation speed ±200 rpm and ultrasonic time ±10 s as variable factors. Three samples were measured in parallel and compared with six samples in the repeatability test to confirm the robustness of the method.
[0066] Three samples were tested under each durability condition and compared with the results of six samples in the repeatability test. If the acceptance criteria shown in Table 1 were met, the durability was considered good under the condition.
[0067] Results and conclusions:
[0068] Table 5. Durability test results at 1800 rpm
[0069]
[0070] Table 6. Durability test results at 2200 rpm
[0071]
[0072] Table 7. Durability test results after 50s of ultrasonic testing.
[0073]
[0074]
[0075] Table 8. Durability test results after 70s of ultrasonic testing.
[0076]
[0077] Conclusions: 1) Under the condition of 1800 rpm, the D(90) of the sample is less than 40 μm, the D(10) is less than 10 μm, the RSD of D(10) is 2.27%, which is less than 30%, the D(50) and D(90) are both greater than 10 μm, the RSD of D(50) is 2.80%, which is less than 10%, and the RSD of D(90) is 2.64%, which is less than 15%. The repeatability meets the acceptance criteria and the method has good robustness.
[0078] 2) Under the condition of 2200 rpm, the D(90) of the sample is less than 40 μm, the D(10) is less than 10 μm, the RSD of D(10) is 2.51%, which is less than 30%, the D(50) and D(90) are both greater than 10 μm, the RSD of D(50) is 3.07%, which is less than 10%, and the RSD of D(90) is 2.62%, which is less than 15%. The repeatability meets the acceptance criteria and the method has good robustness.
[0079] 3) Under the condition of ultrasonic time of 50s, the D(90) of the samples were all less than 40μm, the D(10) was all less than 10μm, the RSD of D(10) was 2.03%, which was less than 30%, the D(50) and D(90) were all greater than 10μm, the RSD of D(50) was 3.03%, which was less than 10%, and the RSD of D(90) was 4.25%, which was less than 15%. The repeatability met the acceptance criteria, and the method had good robustness.
[0080] 4) Under the condition of ultrasonic time of 70s, the D(90) of the samples were all less than 40μm, the D(10) was all less than 10μm, the RSD of D(10) was 2.90%, which was less than 30%, the D(50) and D(90) were all greater than 10μm, the RSD of D(50) was 3.62%, which was less than 10%, and the RSD of D(90) was 4.58%, which was less than 15%. The repeatability met the acceptance criteria, and the method had good robustness.
[0081] Example 4
[0082] After sample preparation, store at room temperature and measure the particle size distribution of the sample solution at 0h, 1h, 2h, 3h, and 4h. (If the sample amount is insufficient for the measurement, the sample preparation can be scaled up proportionally.)
[0083] The acceptable standards are shown in Table 1.
[0084] Results and conclusions:
[0085] Table 9 Results of Solution Stability Test in Example 4
[0086] 0 3.48 10.2 29.5 1 3.44 9.94 27.1 2 3.45 9.90 26.2 3 3.47 9.90 26.0 4 3.48 9.95 26.1 average value 3.46 9.98 27.0 %RSD 0.514 1.28 5.40
[0087] Conclusion: After the same sample was prepared and placed at room temperature, the results measured at each time point were as follows: D(90) was less than 40 μm, D(10) and D(50) were less than 10 μm, D(10) RSD was 0.514% (less than 30%), D(50) RSD was 1.28% (less than 20%), D(90) was greater than 10 μm, and D(90) RSD was 5.40% (less than 15%). The repeatability met the acceptance criteria, and the sample was stable after being placed at room temperature for 4 hours after preparation.
[0088] Comparative Example 1
[0089] A method for detecting the particle size and particle size distribution of tofacitinib citrate raw material, comprising the following steps:
[0090] (1) Turn on the Malvern laser particle size analyzer, preheat for half an hour, and run the particle size testing software;
[0091] (2) Sample solution preparation: Weigh about 0.2g of the raw material of tofacitinib citrate to be tested, add 20mL of ethanol solution of different concentrations (30%, 50%, 60%, 75%, 80%, 95%), stir and sonicate for 60s;
[0092] (3) Set the instrument test parameters:
[0093] The sample has a refractive index of 1.646;
[0094] The sample absorbance is 0.01.
[0095] The dispersant has a refractive index of 1.38;
[0096] The analysis mode is the general mode;
[0097] The background measurement time is 10 seconds.
[0098] The sample testing time is 10 seconds;
[0099] The measurement was performed 3 times;
[0100] The stirring speed is 2000 rpm;
[0101] (4) After the instrument background test is completed, the sample is added to the sample cell of the injector. The occlusion decreases rapidly and cannot be stabilized in the range of 8% to 20%. Therefore, the sample particle size cannot be accurately measured.
[0102] Comparative Example 2
[0103] A method for detecting the particle size and particle size distribution of tofacitinib citrate raw material, comprising the following steps:
[0104] (1) Turn on the Malvern laser particle size analyzer, preheat for half an hour, and run the particle size testing software;
[0105] (2) Sample solution preparation: Weigh about 0.2g of the raw material of tofacitinib citrate to be tested, add 20mL of acetonitrile solution of different concentrations (30%, 50%, 80%, 100%), stir and sonicate for 60s;
[0106] (3) Set the instrument test parameters:
[0107] The sample has a refractive index of 1.646;
[0108] The sample absorbance is 0.01.
[0109] The dispersant has a refractive index of 1.38;
[0110] The analysis mode is the general mode;
[0111] The background measurement time is 10 seconds.
[0112] The sample testing time is 10 seconds;
[0113] The measurement was performed 3 times;
[0114] The stirring speed is 2000 rpm;
[0115] (4) After the instrument background test is completed, the sample is added to the sample cell of the injector. The occlusion decreases rapidly and cannot be stabilized in the range of 8% to 20%. Therefore, the sample particle size cannot be accurately measured.
[0116] Comparative Example 3
[0117] A method for detecting the particle size and particle size distribution of tofacitinib citrate raw material, comprising the following steps:
[0118] (1) Turn on the Malvern laser particle size analyzer, preheat for half an hour, and run the particle size testing software;
[0119] (2) Sample solution preparation: Weigh about 0.2g of the raw material of tofacitinib citrate to be tested, add 20mL of 0.1% Tween 80-n-hexane solution, stir and sonicate for 60s;
[0120] (3) Set the instrument test parameters:
[0121] The sample has a refractive index of 1.646;
[0122] The sample absorbance is 0.01.
[0123] The dispersant has a refractive index of 1.38;
[0124] The analysis mode is the general mode;
[0125] The background measurement time is 10 seconds.
[0126] The sample testing time is 10 seconds;
[0127] The measurement was performed 3 times;
[0128] The stirring speed is 2000 rpm;
[0129] (4) After the instrument background test is completed, the sample is added to the sample cell of the injector. The occlusion decreases rapidly and cannot be stabilized in the range of 8% to 20%. Therefore, the sample particle size cannot be accurately measured.
[0130] Comparative Example 4
[0131] A method for detecting the particle size and particle size distribution of tofacitinib citrate raw material, comprising the following steps:
[0132] (1) Turn on the Malvern laser particle size analyzer, preheat for half an hour, and run the particle size testing software;
[0133] (2) Sample solution preparation: Weigh about 0.2g of the raw material of tofacitinib citrate to be tested, add 20mL of 0.1% span 85-n-hexane solution, stir and sonicate for 60s;
[0134] (3) Set the instrument test parameters:
[0135] The sample has a refractive index of 1.646;
[0136] The sample absorbance is 0.01.
[0137] The dispersant has a refractive index of 1.38;
[0138] The analysis mode is the general mode;
[0139] The background measurement time is 10 seconds.
[0140] The sample testing time is 10 seconds;
[0141] The measurement was performed 3 times;
[0142] The stirring speed is 2000 rpm;
[0143] (4) After the instrument background test is completed, add the test sample into the sample cell of the injector, and add it to the range of 8% to 20% of the light shading. Measure six samples in parallel and compare the test results.
[0144] The relative standard deviation (RSD) of the particle size and particle size distribution characteristics of six parallel samples was greater than 15%, indicating that the repeatability of this comparative method did not meet the acceptance criteria and the method repeatability was poor.
[0145] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of individual raw materials in the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.
Claims
1. A method for detecting the particle size and particle size distribution of tofacitinib citrate raw material, characterized in that, The detection method includes the following steps: take the raw material of tofacitinib citrate to be tested, add 0.1wt% span 80-n-hexane solution as a dispersant, stir ultrasonically until uniformly dispersed, and then detect the obtained sample by wet laser diffraction. The parameters for wet laser diffraction detection are set as follows: sample refractive index 1.6~1.8; sample absorbance 0.01~0.1; dispersant refractive index 1.3~1.
4.
2. The method for detecting the particle size and particle size distribution of tofacitinib citrate raw material according to claim 1, characterized in that, The ultrasonic stirring speed is 1500~2500 rpm, and the stirring time is 30~300 s.
3. The method for detecting the particle size and particle size distribution of tofacitinib citrate raw material according to claim 1, characterized in that, The parameters for wet laser diffraction testing are set as follows: sample refractive index 1.646; sample absorbance 0.01; dispersant refractive index 1.
38.
4. The method for detecting the particle size and particle size distribution of tofacitinib citrate raw material according to claim 1, characterized in that, The parameters for wet laser diffraction testing are set as follows: analysis mode is general mode, sensitivity is normal, number of measurements is 3, background measurement time is 10s, and sample testing time is 10s.
5. The method for detecting the particle size and particle size distribution of tofacitinib citrate raw material according to claim 1, characterized in that, In the wet laser diffraction method, D10, D50, and D90 are used as particle size distribution characteristic values.
6. The method for detecting the particle size and particle size distribution of tofacitinib citrate raw material according to claim 1, characterized in that, In wet laser diffraction testing, when the sample is added to the sample cell of the injector, the shading level should be within the range of 8-20%.
7. The use of the detection method according to any one of claims 1 to 6 in the preparation of tofacitinib citrate.