Method for detecting impurity content in ketorolac tromethamine gel plaster

Abstract

The invention belongs to the technical field of pharmaceutical analysis, and particularly relates to a method for detecting the content of impurities in ketorolac tromethamine gel plaster. According to the method, the ketorolac tromethamine gel plaster is analyzed through a high performance liquid chromatography analysis method so as to obtain a chromatogram, the content of impurities in the ketorolac tromethamine gel plaster is determined on the basis of the chromatogram, and the high performance liquid chromatography adopts the following conditions that a chromatographic column is waters XBridge C18, 3.5 microns and 4.6 * 50 mm; the detector is a DAD; a mobile phase A is 0.05 mol / L ammonium dihydrogen phosphate solution, and the pH value of the ammonium dihydrogen phosphate solution is 3.0; a mobile phase B is acetonitrile; a mobile phase C is tetrahydrofuran; the elution procedure is gradient elution.

Description

Technical Field

[0001] The present invention belongs to the technical field of pharmaceutical analysis, and particularly relates to a method for detecting the impurity content in ketorolac tromethamine gel plaster. Background Art

[0002] Ketorolac tromethamine is a non-steroidal anti-inflammatory drug, which reduces prostaglandin synthesis by inhibiting the activity of cyclooxygenase (COX), thereby exerting anti-inflammatory and analgesic effects. And ketorolac tromethamine gel plaster is an external preparation with ketorolac tromethamine as the active ingredient, and several enterprises have applied for clinical trials.

[0003] At present, the impurity research standards for ketorolac tromethamine gel plaster are not included in the pharmacopoeias of various countries. Referring to the detection methods for impurities in ketorolac tromethamine raw material drugs in the pharmacopoeias of various countries, isocratic elution is carried out using an ammonium dihydrogen phosphate buffer salt and a tetrahydrofuran system. However, due to the large number of excipients in ketorolac tromethamine gel plaster, it is impossible to ensure the complete elution of strongly retained impurities, and it is not suitable to use an ammonium dihydrogen phosphate buffer salt and a tetrahydrofuran system for isocratic elution. And through research, it is found that two unknown degradation impurities exceeding the identification limit will be generated during the stability study of ketorolac tromethamine gel plaster, and these two strongly retained degradation impurities cannot be eluted out by the methods disclosed in the existing technology.

[0004] Therefore, how to accurately determine the types and contents of impurities in ketorolac tromethamine gel plaster, so as to effectively control the impurities in ketorolac tromethamine gel plaster, and further effectively control the quality of ketorolac tromethamine gel plaster products in the drug R & D stage and the product listing stage has become a key problem to be solved. Summary of the Invention

[0005] The present invention aims to propose a method for detecting the contents of various impurities in ketorolac tromethamine gel plaster, which is simple to operate, accurate and sensitive in results.

[0006] On the one hand, the present invention provides a method for detecting the impurity content in ketorolac tromethamine gel plaster, analyzing the ketorolac tromethamine gel plaster by a high performance liquid chromatography analysis method to obtain a chromatogram, and determining the impurity content in the ketorolac tromethamine gel plaster based on the chromatogram, wherein the high performance liquid chromatography adopts the following conditions: Chromatographic column: waters XBridge C18, 3.5μm, 4.6×50mm; Detector: DAD; Mobile phase A: 0.05mol / L ammonium dihydrogen phosphate solution; Mobile phase B: acetonitrile; Mobile phase C: tetrahydrofuran; The gradient elution procedure is as follows: ; The impurities are: Impurity A , Impurity B , Impurity E , Impurity I , Impurity X .

[0007] During the stability study of ketorolac tromethamine cataplasm, two unknown degradation impurities beyond the identification limit will be generated, namely Degradation Impurity 1 and Degradation Impurity 2. Among them, Impurity X is Degradation Impurity 1, and the structure of Degradation Impurity 2 cannot be characterized temporarily. Toxicological studies have been conducted on Degradation Impurity 2 and it has no toxicity. The retention time (RRT) in the chromatogram is about 2.2, and the impurity eluting at this retention time can be controlled accordingly.

[0008] In some embodiments, the pH value of the ammonium dihydrogen phosphate solution is 3.0.

[0009] In some embodiments, the pH value of the ammonium dihydrogen phosphate solution is adjusted with phosphoric acid.

[0010] In some embodiments, the column temperature of the high performance liquid chromatography is 40°C.

[0011] In some embodiments, the flow rate of the high performance liquid chromatography is 1.0 mL / min.

[0012] In some embodiments, the detection wavelength of the high performance liquid chromatography is 313 nm.

[0013] In some embodiments, the injection volume of the high performance liquid chromatography is 20 μL.

[0014] In some embodiments, the ketorolac tromethamine cataplasm is provided in the form of a test solution, wherein the test solution is a methanol solution of ketorolac tromethamine cataplasm, and based on each milliliter of the test solution, the concentration of ketorolac tromethamine is 0.5 mg / mL.

[0015] In some embodiments, based on the chromatogram, the impurity content of the ketorolac tromethamine cataplasm is determined by area normalization method: .

[0016] On the other hand, the present invention provides a more detailed method for detecting the impurity content in ketorolac tromethamine cataplasm, including: (1) Chromatographic conditions Chromatographic column: waters XBridge C18, 3.5 μm, 4.6×50 mm; Detector: DAD; Mobile phase A: 0.05 mol / L ammonium dihydrogen phosphate solution with a pH value of 3.0 for the ammonium dihydrogen phosphate solution; Mobile phase B: Acetonitrile; Mobile phase C: Tetrahydrofuran; Flow rate: 1.0 mL / min; Column temperature: 40 °C; Wavelength: 313 nm; Injection volume: 20 μL; The gradient elution program is as follows: ; (2) Prepare the blank solution Measure 750 ml of methanol, add 250 ml of ultrapure water, mix well to obtain a 75% methanol solution; (3) Prepare the stock solution of impurity reference substances Take about 2.5 mg of each of impurities A, E, and I, 4 mg of impurity B, and 12.5 mg of impurity X, place them in 50 mL volumetric flasks respectively, dissolve with methanol and dilute to the mark, shake well to obtain the stock solution of impurity reference substances; (4) Prepare the system suitability solution Take about 10 mg of tromethamine ketorolac raw material drug, place it in a 20 mL volumetric flask, add an appropriate amount of 50% methanol to dissolve the tromethamine ketorolac raw material drug, then add 1 mL of each of the stock solutions of impurities A, B, E, I, and X respectively, dilute to the mark with 50% methanol to prepare a solution containing 0.5 mg / mL of tromethamine ketorolac, 2.5 μg / mL of each of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and that's it; (5) Prepare the blank excipient solution Take 1 patch of tromethamine ketorolac blank gel patch, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, sonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard the first 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, dilute to the mark with 50% methanol, shake well, and filter through a 0.45 μm filter membrane to obtain it; (6) Prepare the test solution Take 1 patch of tromethamine ketorolac gel patch, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, sonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard the first 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, dilute to the mark with 50% methanol, shake well, and filter through a 0.45 μm filter membrane to prepare a solution containing 0.5 mg / mL of tromethamine ketorolac, and that's it; (7) Preparation of spiked test solution Take 1 patch of ketorolac tromethamine cataplasm, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, sonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, add 0.5 mL of each of the reference substance stock solutions of impurities A, B, E, I, and X, dilute to the mark with ultrapure water to prepare a solution containing 0.5 mg / mL of ketorolac tromethamine, 2.5 μg / mL of each of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and you will get it; (8)Injection Inject 20 μL each of the blank solution, blank excipient solution, system suitability solution, test solution or spiked test solution into the liquid chromatograph, and record the chromatogram; (9)Calculation Based on the chromatogram, it is determined that the impurity content of the ketorolac tromethamine cataplasm is calculated by the area normalization method: .

[0017] It can be understood that the polarity differences among the impurities are very large. Some impurities have a relatively large polarity and have weak retention or almost no retention in the chromatographic system, while some impurities have a relatively small polarity and have extremely strong retention in the chromatographic system and are not easily eluted. Using the method for determining the contents of multiple impurities in ketorolac tromethamine cataplasm provided by the present invention, the main peak of the ketorolac tromethamine cataplasm and the above-mentioned impurity peaks all reach baseline separation, the resolution of the above-mentioned impurity peaks is also good, the impurity peak shape is single, and the effective separation and content determination of each impurity can be realized.

[0018] Using the detection method provided by the present invention, the contents of 6 impurities in ketorolac tromethamine cataplasm can be simply, accurately and sensitively detected for the first time, and the effective separation and content determination of each impurity can be realized. Description of the Drawings

[0019] Figure 1 It is the chromatogram of the system suitability solution obtained under the chromatographic conditions described in Example 1; Figure 2 It is the chromatograms of the test solution (a), system suitability solution (b) and blank excipient solution (c) obtained under the chromatographic conditions described in Example 2; Figure 3 It is the chromatogram of the test solution obtained under the chromatographic conditions described in Example 3; Figure 4 It is the chromatogram of the test solution obtained under the chromatographic conditions described in Example 4; Figure 5Chromatogram of the test sample spiked solution obtained under the chromatographic conditions described in Example 5; Figure 6 Chromatogram of the test sample spiked solution obtained under the chromatographic conditions of elution gradient 1 described in Example 6; Figure 7 Chromatogram of the test sample spiked solution obtained under the chromatographic conditions of elution gradient 2 described in Example 6; Figure 8 Chromatogram of the test sample spiked solution obtained under the chromatographic conditions of elution gradient 3 described in Example 6; Figure 9 Superimposed chromatogram of the blank solvent (d), blank excipient solution (e), blank excipient photo-degraded solution (f), self-developed preparation non-degraded solution (g), and self-developed preparation photo-degraded solution (h) described in Example 8; Explanation of the reference numerals in the drawings: 1: main peak (the peak of tromethamine ketorolac); 2: peak of impurity B; 3: peak of impurity X; 4: peak of degradation impurity 2; 5: unknown impurity 1; 6: unknown impurity 2; 7: peak of impurity E; 8: peak of impurity A; 9: peak of impurity I; 10: peak of unknown impurity 3; 11: peak of unknown impurity 4; 12: peak of excipient. Detailed implementation manners

[0020] For the convenience of understanding, the present application will be described more comprehensively below, and preferred embodiments of the present application are given. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive. For those techniques or conditions not specified in the examples, they shall be carried out according to the techniques or conditions described in the literature in this field or according to the product specifications. For the reagents or instruments not indicated with the manufacturer, they are all conventional products that can be obtained through the market.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0022] The 50% methanol solution described in the present application means that the volume or mass ratio of methanol in the aqueous solution is 50%, and the methanol without content indication is pure methanol; the tromethamine ketorolac blank gel patch refers to a gel patch without tromethamine ketorolac (the other excipients are the same as those of the gel patch containing tromethamine ketorolac).

[0023] Example 1 Method reproducibility Reproduce the detection methods for the impurity contents in tromethamine ketorolac raw materials in various pharmacopoeias: (1)Chromatographic conditions Mobile phase: 0.05 mol / L ammonium dihydrogen phosphate solution (adjust the pH value to 3.0 with phosphoric acid) - tetrahydrofuran, isocratic elution at a ratio of 70:30; Chromatographic column: Agilent ZORBOX SB-C18, 4.6 mm × 250 mm, 5 μm; Flow rate: 1.0 mL / min; Column temperature: 40 °C; Wavelength: 313 nm; Injection volume: 20 μL; (2)Preparation of system suitability solution Weigh about 10 mg of tromethamine ketorolac raw material, place it in a 20 mL volumetric flask, add an appropriate amount of 50% methanol to dissolve the tromethamine ketorolac raw material, then add 1 mL of each of the stock solutions of impurities A, B, E, I, and X respectively, and dilute to the mark with 50% methanol to prepare a solution containing 0.5 mg / mL of tromethamine ketorolac, 2.5 μg / mL of each of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and that's it; The system suitability chromatogram obtained under the chromatographic conditions of Example 1 is as Figure 1 shown, Figure 1 The corresponding peak position information table is as shown in Table 1 below. The resolution between the main peak and the adjacent impurity peak (impurity B) is only 1.10, not meeting the requirements; Table 1 Figure 1 Peak position information table corresponding to the shown chromatogram .

[0024] Example 2 Gradient optimization (1)Chromatographic conditions Mobile phase A: 0.05 mol / L ammonium dihydrogen phosphate solution (adjust the pH value to 3.0 with phosphoric acid); Mobile phase B: tetrahydrofuran; Chromatographic column: Agilent ZORBOX SB-C18, 4.6 mm × 250 mm, 5 μm; Flow rate: 1.0 mL / min; Column temperature: 40 °C; Wavelength: 313 nm; Injection volume: 20 μL; Gradient elution: Table 2 Elution gradient of Example 2 ; (2)Preparation of system suitability solution Weigh about 10 mg of tromethamine ketorolac raw material medicine, place it in a 20 mL volumetric flask, add an appropriate amount of 50% methanol to dissolve the tromethamine ketorolac raw material medicine, then add 1 mL of each of the stock solutions of impurities A, B, E, I, and X respectively, and dilute to the scale with 50% methanol to prepare a solution containing 0.5 mg / mL of tromethamine ketorolac, 2.5 μg / mL of each of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and that's it; (3) Preparation of blank excipient solution Take 1 patch of tromethamine ketorolac blank gel patch, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, after cooling to room temperature, shake well, filter through a 0.45 μm filter membrane, discard 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, dilute to the scale with 50% methanol, shake well, and filter through a 0.45 μm filter membrane, and that's it; (4) Preparation of test solution Take 1 patch of tromethamine ketorolac gel patch, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, after cooling to room temperature, shake well, filter through a 0.45 μm filter membrane, discard 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, dilute to the scale with 50% methanol, shake well, and filter through a 0.45 μm filter membrane to prepare a solution containing 0.5 mg / mL of tromethamine ketorolac, and that's it; The chromatograms of the test solution, system suitability solution, and blank excipient solution obtained under the chromatographic conditions described in Example 2 are as Figure 2 shown. A strongly retained impurity (degradation impurity 2) is newly detected in the test solution. The first impurity after the main peak is unknown impurity 1, which is an esterification impurity of API and methanol and is introduced by the solvent and does not need to be statistically analyzed. However, there is a peak at the position where impurity B elutes in the test solution for the blank excipient, interfering with the detection of impurity B, and it is not suitable to use this chromatographic condition for detection.

[0025] Example 3 Optimization of the type and ratio of mobile phase B (1) Chromatographic conditions Mobile phase A: 0.05 mol / L ammonium dihydrogen phosphate solution (adjust the pH value to 3.0 with phosphoric acid); Mobile phase B: tetrahydrofuran - acetonitrile (50∶50); Chromatographic column: Agilent ZORBOX SB-C18, 4.6 mm × 250 mm, 5 μm; Flow rate: 1.0 mL / min; Column temperature: 40 °C; Wavelength: 313 nm; Injection volume: 20 μL; Gradient elution: Table 3 Elution gradient of Example 3 ; (2) Preparation of system suitability solution Weigh about 10 mg of tromethamine ketorolac raw material drug, place it in a 20 mL volumetric flask, add an appropriate amount of methanol to dissolve the tromethamine ketorolac raw material drug, then add 1 mL of each of the stock solutions of impurities A, B, E, I, and X, and dilute to the mark with 50% methanol to prepare a solution containing 0.5 mg / mL of tromethamine ketorolac, 2.5 μg / mL of each of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and you will get it; (3) Preparation of test solution Take 1 patch of tromethamine ketorolac gel plaster, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, dilute to the mark with 50% methanol, shake well, and filter through a 0.45 μm filter membrane to prepare a solution containing 0.5 mg / mL of tromethamine ketorolac, and you will get it; The chromatogram of the test solution obtained under the chromatographic conditions described in Example 3 is as Figure 3 shown. There is another unknown impurity 2 (it is speculated that unknown impurity 2 is an isomeric impurity of impurity X, and its structure cannot be characterized temporarily. Toxicological investigation has been carried out and it has no toxicity, with an RRT of about 0.8. The impurity eluting at this retention time can be controlled) wrapped in front of the peak of impurity X in the test solution, and the resolution does not meet the requirements, so it is not suitable to use this chromatographic condition for detection.

[0026] Example 4 Synchronous optimization of chromatographic column and mobile phase (1) Chromatographic conditions Mobile phase A: 0.05 mol / L ammonium dihydrogen phosphate solution (adjust the pH value to 3.0 with phosphoric acid); Mobile phase B: acetonitrile; Mobile phase C: tetrahydrofuran; Chromatographic column: MN EC 150 / 4.6 NUCLEOSIL 100-5 C18 (3 mm × 150 mm, 5 μm); Flow rate: 1.0 mL / min; Column temperature: 40 °C; Wavelength: 313 nm; Injection volume: 20 μL; Gradient elution: Table 4 Elution gradient of Example 4 ; (2) Preparation of system suitability solution Weigh about 10 mg of ketorolac tromethamine raw material, place it in a 20 mL volumetric flask, add an appropriate amount of methanol to dissolve the ketorolac tromethamine raw material, then add 1 mL of each of the stock solutions of impurities A, B, E, I, and X respectively, and dilute to the mark with 50% methanol to prepare a solution containing 0.5 mg / mL of ketorolac tromethamine, 2.5 μg / mL of each of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and that's it; (3) Preparation of test solution Take 1 patch of ketorolac tromethamine gel plaster, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard the first 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, dilute to the mark with 50% methanol, shake well, filter through a 0.45 μm filter membrane to prepare a solution containing 0.5 mg / mL of ketorolac tromethamine, and that's it; The chromatogram of the test solution obtained under the chromatographic conditions described in Example 4 is as Figure 4 shown. The resolution between impurity X and the unknown impurity peak still does not meet the requirements, and it is not suitable to use this chromatographic condition for detection.

[0027] Further optimization of the chromatographic column in Example 5 (1) Chromatographic conditions Mobile phase A: 0.05 mol / L ammonium dihydrogen phosphate solution (adjust the pH value to 3.0 with phosphoric acid); Mobile phase B: acetonitrile; Mobile phase C: tetrahydrofuran; Chromatographic column: waters XBridge C18 3.5 μm 4.6 mm×50 mm; Flow rate: 1.0 mL / min; Column temperature: 40 °C; Wavelength: 313 nm; Injection volume: 20 μL; Gradient elution: Table 5 Elution gradient in Example 5 ; (2) Preparation of test solution with added standard Take 1 patch of ketorolac tromethamine gel plaster, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, sonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm membrane filter, discard 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, add 0.5 mL of each of the reference substance stock solutions of impurities A, B, E, I, and X, dilute to the mark with ultrapure water to prepare a solution containing 0.5 mg / mL of ketorolac tromethamine, 2.5 μg / mL of each of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and that's it; The chromatogram of the spiked test solution obtained under the chromatographic conditions described in Example 5 is as shown in Figure 5 the figure. In the spiked test solution, it is known that impurity A is interfered by impurity X, and the degraded impurity 2 does not peak, but each peak elutes relatively quickly and has a good peak shape, indicating that there is a large space for method optimization. Therefore, the gradient is further optimized based on this chromatographic column.

[0028] Further Optimization of the Gradient in Example 6 (1) Chromatographic Conditions Mobile phase A: 0.05 mol / L ammonium dihydrogen phosphate solution (adjust the pH value to 3.0 with phosphoric acid); Mobile phase B: acetonitrile; Mobile phase C: tetrahydrofuran; Chromatographic column: waters XBridge C18 3.5 μm 4.6 mm×50 mm; Flow rate: 1.0 mL / min; Column temperature: 40 °C; Wavelength: 313 nm; Injection volume: 20 μL; Elution gradient: Table 6 Elution Gradient 1 in Example 6 ; Table 7 Elution Gradient 2 in Example 6 ; Table 8 Elution Gradient 3 in Example 6 ; (2) Preparation of the System Suitability Solution Weigh about 10 mg of ketorolac tromethamine bulk drug, place it in a 20 mL volumetric flask, add an appropriate amount of methanol to dissolve the ketorolac tromethamine bulk drug, then add 1 mL of each of the stock solutions of impurities A, B, E, and I, and dilute to the mark with 50% methanol to prepare a solution containing 0.5 mg / mL of ketorolac tromethamine, 2.5 μg / mL of each of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and that's it; (3) Preparation of spiked test solution Take 1 patch of ketorolac tromethamine cataplasm, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, sonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, add 0.5 mL of each of the reference substance stock solutions of impurities A, B, E, I, and X, dilute to the mark with ultrapure water to prepare a solution containing 0.5 mg / mL of ketorolac tromethamine, 2.5 μg / mL of each of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and you will get it; The chromatograms of the spiked test solution obtained under the chromatographic conditions of elution gradient 1, elution gradient 2, and elution gradient 3 described in Example 6 are as shown in Figure 6 、 Figure 7 、 Figure 8 shown, Figure 6 、 Figure 7 、 Figure 8 and the corresponding peak position information tables are shown in Table 10, Table 11, and Table 12. According to Figures 6 - 8 shown, as the proportion of tetrahydrofuran in the mobile phase gradually decreases, the resolution between impurity X and the adjacent peak becomes better and better, and the resolution between impurity B and the main peak gradually decreases, but it is still within the acceptable range; the resolution between impurity E (RT = 7 - 8.5 min) and degradation impurity 2 (RT = 33 - 34 min) and unknown impurity 3 and unknown impurity 4 gradually improves (the contents of unknown impurity 3 and unknown impurity 4 are less than 0.05% and are not controlled temporarily); therefore, elution gradient 3 is finally selected as the final elution gradient for the impurity detection method. At the same time, to ensure the complete elution of strongly retained impurities, the time of the high proportion organic phase is extended by 5 min (on the basis of elution gradient 3, the proportion elution from 31 - 40 min is extended by 5 min to 31 - 45 min). The comparison of the liquid phase analysis results of the spiked test solution (impurities are calculated by the peak area normalization method) is shown in Table 8: Table 9 Comparison of liquid phase analysis results of spiked test solution ; Table 10 Figure 6 Peak position information table corresponding to the chromatogram shown ; Table 11 Figure 7 Peak position information table corresponding to the chromatogram shown ; Table 12 Figure 8 Peak position information table corresponding to the chromatogram shown .

[0029] Example 7 Wavelength Confirmation Table 13 Maximum Absorption Wavelength Table of Each Impurity ; The above results show that each impurity has the maximum absorption near the wavelength of 313 nm. The detection wavelengths for related substances in the pharmacopoeias of various countries for the reference bulk drug are all 313 nm. Therefore, 313 nm is selected as the detection wavelength.

[0030] Example 8 Forced Degradation Study The ketorolac tromethamine gel plaster under each destruction condition was subjected to forced degradation study using the determined final method: (1) Chromatographic Conditions Chromatographic column: waters XBridge C18, 3.5 μm, 4.6×50 mm; Detector: DAD; Mobile phase A: 0.05 mol / L ammonium dihydrogen phosphate solution, with the pH value of the ammonium dihydrogen phosphate solution being 3.0; Mobile phase B: Acetonitrile; Mobile phase C: Tetrahydrofuran; Flow rate: 1.0 mL / min; Column temperature: 40 °C; Wavelength: 313 nm; Injection volume: 20 μL; The gradient elution program is as follows: Table 14 Elution Gradient of Example 8 ; (2) Preparation of Blank Solution 75% Methanol: Measure 750 mL of methanol, add 250 mL of ultrapure water, mix well, and obtain it; (3) Preparation of Impurity Reference Stock Solution Take about 2.5 mg of each of impurities A, E, and I, 4 mg of impurity B, and 12.5 mg of impurity X, and place them in 50 mL volumetric flasks respectively. Dissolve them with methanol and dilute to the mark, shake well to obtain the impurity reference stock solution; (4) Preparation of System Suitability Solution Take about 10 mg of ketorolac tromethamine bulk drug, place it in a 20 mL volumetric flask, add an appropriate amount of 50% methanol to dissolve the ketorolac tromethamine bulk drug, then add 1 mL of each of the stock solutions of impurities A, B, E, I, and X, and dilute to the mark with 50% methanol to prepare a solution containing 0.5 mg / mL of ketorolac tromethamine, 2.5 μg / mL of each of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and obtain it; (5) Preparation of Blank Excipient Solution Take 1 patch of ketorolac tromethamine blank cataplasm, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, dilute to the mark with 50% methanol, shake well, filter through a 0.45 μm filter membrane, and you will get it; (6)Prepare the test solution Take 1 patch of ketorolac tromethamine cataplasm, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, dilute to the mark with 50% methanol, shake well, filter through a 0.45 μm filter membrane, and prepare a solution containing 0.5 mg / mL of ketorolac tromethamine, and you will get it; (7)Prepare the spiked test solution Take 1 patch of ketorolac tromethamine cataplasm, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, add 0.5 mL of each of the reference substance stock solutions of impurities A, B, E, I, and X, dilute to the mark with ultrapure water, and prepare a solution containing 0.5 mg / mL of ketorolac tromethamine, 2.5 μg / mL of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and you will get it; (8)Prepare the damaged test solution Light-damaged solution: Take 1 patch of ketorolac tromethamine cataplasm (the paste is yellow) placed in a light box ((5000 ± 500 lux, near-ultraviolet energy 90 μw / cm 2 ) for 4 h, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter head, accurately measure 5 mL of the subsequent filtrate, place it in a 10 mL volumetric flask, dilute to the mark with 50% methanol, shake well, filter through a 0.45 μm filter head, and take the subsequent filtrate, and you will get it; High-temperature damaged solution: Take 1 patch of ketorolac tromethamine cataplasm placed at 60 °C for 1 day, place it in a 250 mL stoppered conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter head, accurately measure 5 mL of the subsequent filtrate, place it in a 10 mL volumetric flask, dilute to the mark with 50% methanol, shake well, filter through a 0.45 μm filter head, and take the subsequent filtrate, and you will get it; Acid-destroyed solution: Take 1 patch of ketorolac tromethamine cataplasm, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 50 mL of 1 mol / L hydrochloric acid solution, shake well, seal and let stand at room temperature for 24 h, then add 10 mL of 5 mol / L sodium hydroxide solution to neutralize. Then add 140 mL of methanol, shake for 1 h, sonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter head, and take the subsequent filtrate to obtain the solution; Alkali-destroyed solution: Take 1 patch of ketorolac tromethamine cataplasm, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 50 mL of 1 mol / L sodium hydroxide solution, shake well, seal and let stand at room temperature for 24 h, then add 10 mL of 5 mol / L hydrochloric acid solution to neutralize. Then add 140 mL of methanol, shake for 1 h, sonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter head, and take the subsequent filtrate to obtain the solution; Oxidation-destroyed solution: Take 1 patch of ketorolac tromethamine cataplasm, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 80 mL of methanol, shake well, add 20 mL of 30% hydrogen peroxide, shake well, seal and let stand at room temperature in the dark for 24 h, then add 100 mL of methanol, shake for 1 h, sonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter head, and take the subsequent filtrate to obtain the solution; Blank excipient-destroyed test solution: Prepared in the same way as each test solution; (9)Injection After the system suitability is qualified, take the undestroyed solution (1 injection each), acid-destroyed solution (1 injection each), alkali-destroyed solution (1 injection each), high-temperature-destroyed solution (1 injection each), oxidation-destroyed solution (1 injection each), and light-destroyed solution (1 injection each), inject them into the liquid chromatograph, and record the chromatogram; (10)Calculation 1) Total peak area = sample main peak area + each impurity peak area; 2) Material balance (%) = (total peak area of destroyed sample / (weight of destroyed sample / dilution factor)) / (total peak area of undestroyed sample / (weight of undestroyed sample / dilution factor)) × 100; 3) Degradation rate (%) = 100 - (main peak area of destroyed sample / (weight of destroyed sample / dilution factor)) / (main peak area of undestroyed sample / (weight of undestroyed sample / dilution factor)) × 100; Use this method to conduct a forced degradation study on this product: Table 15 Results of forced degradation study ; Conclusion: 1. The blank solution and the blank excipient solution under each degradation condition (acid, base, oxidation, high temperature, and light degradation) showed no interference in the detection of the main peak and each impurity peak. As Figure 9 shown, from bottom to top are the chromatograms of the blank solvent, the blank excipient solution, the blank excipient solution under light degradation, the self-developed preparation without degradation, and the self-developed preparation under light degradation, which meet the acceptable standards; 2. The minimum resolution between the main peak and the adjacent peak in each degradation solution was 2.15, greater than 1.5, meeting the acceptable standards; 3. The material balance of each degradation solution was between 98.7% and 102.4%, meeting the acceptable standards (90% - 110%); 4. The purity angle of the main peak in each degradation solution was less than the purity threshold, meeting the acceptable standard that the chromatographic peak purity is acceptable when the purity angle of the main peak is less than the purity threshold.

[0031] Based on the results of forced degradation studies, this method meets the acceptable standards.

[0032] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for detecting the impurity content in ketorolac tromethamine cataplasm, characterized in that, Analyze the ketorolac tromethamine gel patch by high performance liquid chromatography (HPLC) method to obtain a chromatogram, and based on the chromatogram, determine the content of impurities in the ketorolac tromethamine gel patch, wherein the HPLC is carried out under the following conditions: Chromatographic column: waters XBridge C18, 3.5μm, 4.6×50mm; Detector: DAD; Mobile phase A: 0.05mol / L ammonium dihydrogen phosphate solution; Mobile phase B: Acetonitrile; Mobile phase C: Tetrahydrofuran; The gradient elution program is as follows: ； The impurities are: impurity A , impurity B , impurity E , impurity I , impurity X .

2. The detection method according to claim 1, characterized in that, The pH value of the ammonium dihydrogen phosphate solution is 3.

0.

3. The detection method according to claim 2, wherein The pH value of the ammonium dihydrogen phosphate solution is adjusted by phosphoric acid.

4. The detection method according to claim 1, wherein The column temperature of the HPLC is 40°C.

5. The detection method according to claim 1, characterized in that The flow rate of the HPLC is 1.0mL / min.

6. The detection method according to claim 1, wherein The detection wavelength of the HPLC is 313nm.

7. The detection method according to claim 1, characterized in that The injection volume of the HPLC is 20μL.

8. The detection method according to claim 1, wherein The ketorolac tromethamine gel patch is provided in the form of a test solution, wherein the test solution is a methanol solution of the ketorolac tromethamine gel patch, and based on each milliliter of the test solution, the concentration of ketorolac tromethamine is 0.5mg / mL.

9. The detection method according to claim 1, characterized in that Based on the chromatogram, determine the impurity content of the ketorolac tromethamine gel patch by area normalization method: 。 10. A method for detecting the impurity content in ketorolac tromethamine cataplasm, characterized in that, Including: (1) Chromatographic conditions Chromatographic column: waters XBridge C18, 3.5μm, 4.6×50mm; Detector: DAD; Mobile phase A: 0.05mol / L ammonium dihydrogen phosphate solution, the pH value of the ammonium dihydrogen phosphate solution is 3.0; Mobile phase B: Acetonitrile; Mobile phase C: Tetrahydrofuran, Flow rate: 1.0mL / min; Column temperature: 40°C; Wavelength: 313nm; Injection volume: 20μL; The gradient elution program is as follows: ； (2) Prepare a blank solution Measure 750ml of methanol, add 250ml of ultrapure water, mix well, and obtain a 75% methanol solution; (3) Prepare a stock solution of impurity reference substances Take 2.5mg of impurity A, E, and I each, 4mg of impurity B, and 12.5mg of impurity X, place them in 50mL volumetric flasks respectively, dissolve with methanol and dilute to the mark, and shake well to obtain a stock solution of impurity reference substances; (4) Prepare a system suitability solution Take 10mg of ketorolac tromethamine raw material medicine, place it in a 20mL volumetric flask, add an appropriate amount of 50% methanol to dissolve the ketorolac tromethamine raw material medicine, then add 1mL of the stock solutions of impurity A, B, E, I, and X respectively, and dilute to the mark with 50% methanol to prepare a solution containing 0.5mg / mL of ketorolac tromethamine, 2.5μg / mL of impurity A, E, and I each, 4μg / mL of impurity B, and 12.5μg / mL of impurity X, that is obtained; (5) Prepare a blank excipient solution Take 1 patch of ketorolac tromethamine blank cataplasm, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard the first 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, dilute to the mark with 50% methanol, shake well, and filter through a 0.45 μm filter membrane to obtain the solution; (6)Prepare the test solution Take 1 patch of ketorolac tromethamine cataplasm, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard the first 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, dilute to the mark with 50% methanol, shake well, and filter through a 0.45 μm filter membrane to prepare a solution containing 0.5 mg / mL of ketorolac tromethamine, and obtain the solution; (7)Prepare the spiked test solution Take 1 patch of ketorolac tromethamine cataplasm, weigh it, remove the protective layer, place it in a 250 mL brown conical flask, add 100 mL of methanol, shake for 1 h, ultrasonicate for 30 min, cool to room temperature, shake well, filter through a 0.45 μm filter membrane, discard the first 1 mL of the initial filtrate, accurately measure 5 mL of the subsequent filtrate into a 10 mL volumetric flask, add 0.5 mL of each of the reference stock solutions of impurities A, B, E, I, and X, dilute to the mark with ultrapure water to prepare a solution containing 0.5 mg / mL of ketorolac tromethamine, 2.5 μg / mL of each of impurities A, E, and I, 4 μg / mL of impurity B, and 12.5 μg / mL of impurity X, and obtain the solution; (8)Inject the sample Inject 20 μL of each of the blank solution, blank excipient solution, system suitability solution, and test solution into the liquid chromatograph, and record the chromatogram; inject 20 μL of each of the blank solution, blank excipient solution, system suitability solution, and spiked test solution into the liquid chromatograph, and record the chromatogram; (9)Calculate Based on the chromatogram, determine that the impurity content of the ketorolac tromethamine cataplasm is calculated by the area normalization method: 。

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