Method for detecting related substances of dexketoprofen trometamol preparation

Abstract

The invention discloses a method for detecting related substances of a dexketoprofen trometamol preparation, which comprises the following steps of: taking a sample to be detected, and detecting by adopting high performance liquid chromatography under the chromatographic conditions that a chromatographic column takes octadecylsilane chemically bonded silica as a filling agent; a mobile phase: taking a phosphate buffer solution and water as a mobile phase A; acetonitrile is used as a mobile phase B; and the detection wavelengths are 210 nm and 233 nm. According to the method, related substances including five known impurities can be separated at the same time within 60 minutes, and the method is not interfered by solvents, auxiliary materials and the like. Related impurities at the level of 100 ppm are analyzed at the same time in one experiment, and quantitative analysis can be carried out without using expensive impurity reference substances, so that the quality control problem of the dexketoprofen trometamol preparation is solved, and quality control on the dexketoprofen trometamol preparation is facilitated.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical testing, specifically to a method for detecting related substances in dexketoprofen tromethamine preparations. Background Technology

[0002] Dexketoprofen is the active dextrorotatory isomer of the nonsteroidal anti-inflammatory drug ketoprofen. Dexketoprofen tromethamine is the water-soluble tromethamine salt of dexketoprofen, originally developed by the Italian company Menarini and launched in Spain in 1996. It is primarily used to relieve moderate to severe postoperative pain and can also treat mild to moderate pain of various causes. Dexketoprofen tromethamine is available in tablets, capsules, and injections, and is marketed in Spain, Italy, the UK, Australia, Turkey, China, and other countries. The structural formula of dexketoprofen tromethamine is as follows:

[0003]

[0004] Related substances mainly refer to impurities introduced during drug manufacturing, such as starting materials, intermediates, polymers, by-reaction products, and degradation products during drug storage. These impurities generally have chemical structures similar to or related to the active ingredient. The impurity profile in the formulation may differ from that of the active pharmaceutical ingredient (API). Related substances in a formulation primarily refer to its degradation products, as the new chemical structures formed during their formation often interfere with the content of the active pharmaceutical ingredient (API), introduce toxic risks, and reduce patient benefits. Establishing methods to assess related substances in drug formulations can clarify the quality changes of drugs during production and storage, providing support for improving drug quality.

[0005] Dextromethorphan tromethamine is photosensitized and can be degraded by ambient light during its formulation. The resulting degradation products can cause hemolysis, lipid peroxidation, and damage to proteins and nucleic acid chains through various mechanisms. Reports indicate that photodegradation products such as impurity I and impurity V have shown significant toxicity to cultured hepatocytes. Therefore, establishing methods to determine relevant substances in drug formulations to study degradation pathways and products is crucial for reducing adverse drug reactions and guiding rational drug use in clinical practice.

[0006] There are many literature and data reports on related substances of ketoprofen, but there are few reports on related substances in dexketoprofen tromethamine preparations, and no research on analytical methods for the determination of related substances in dexketoprofen tromethamine preparations has been found. Summary of the Invention

[0007] To address the above problems, this invention provides a method for detecting related substances in dexketoprofen tromethamine preparations, comprising the following steps: taking the sample to be tested and detecting it using high-performance liquid chromatography (HPLC) under the following chromatographic conditions:

[0008] Column: Packed with octadecylsilane-bonded silica gel;

[0009] Mobile phase: phosphate buffer and water as mobile phase A; acetonitrile as mobile phase B;

[0010] The detection wavelengths are 210nm and 233nm;

[0011] Gradient elution procedure:

[0012]

[0013] Furthermore, it includes the following steps:

[0014] ② Preparation of test solution: Take the sample to be tested, add solvent to dissolve it, and the solution is obtained;

[0015] ② The test solution was analyzed by high performance liquid chromatography and the chromatogram was recorded. The chromatographic conditions were as follows: the column was a Waters XTERRA MS C18, 4.6 mm × 250 mm, 3.5 μm or a column with equivalent performance; the mobile phase A was phosphate buffer and water in a volume ratio of 2:55.

[0016] Furthermore, in step ①, the mass-to-volume ratio of the sample to the solvent is equivalent to 10-25 mg of dextroprofen: 25 ml of solvent.

[0017] Furthermore, the solvent is a mixed solution of an aqueous solution of phosphoric acid with a pH of 3.0 ± 0.3 and acetonitrile.

[0018] Furthermore, the volume ratio of the phosphoric acid aqueous solution to acetonitrile is 50-90:10-50, preferably 60:40.

[0019] Furthermore, the phosphate buffer in the mobile phase A contains 68.0 g of potassium dihydrogen phosphate per 1 L, and the pH is adjusted to 3.5 ± 0.5 with phosphoric acid.

[0020] Furthermore, the chromatographic conditions also include a flow rate of 0.5–1.8 ml / min; a column temperature of 25–50 °C; an injection volume of 10–50 μl, preferably a flow rate of 1.0 ml / min; a column temperature of 30–50 °C; and an injection volume of 20 μl.

[0021] Furthermore, the chromatogram of the sample to be tested shows chromatographic peaks of related substances, and the content of related substances is calculated by the area normalization method; the related substances are selected from at least one of the following impurities:

[0022] Impurity I: Impurity II:

[0023] Impurity III:

[0024] Impurity IV:

[0025] Impurity V:

[0026] Furthermore, the relative retention times of the related substance chromatographic peaks and the dexketoprofen tromethamine chromatographic peaks are respectively: impurity I 1.27, impurity II 0.35, impurity III 0.24, impurity IV 2.10, and impurity V 2.24.

[0027] Furthermore, the contents of impurity I, impurity II and impurity III are calculated by multiplying the peak area of ​​the chromatographic peak at a wavelength of 210 nm by a correction factor of 1.3; impurity IV, impurity V and other impurities are calculated by the peak area at a wavelength of 233 nm.

[0028] The detection method provided by this invention uses a specific solvent to treat the dexketoprofen tromethamine preparation as the test solution for high-performance liquid chromatography (HPLC). With the aid of a specific chromatographic column and under specific chromatographic conditions, it can simultaneously separate related substances within 60 minutes, unaffected by interference from solvents or excipients. Furthermore, it allows for the simultaneous analysis of related substances at a level of 100 ppm in a single experiment. By determining the retention time of the chromatographic peaks of related substances in the chromatogram of the dexketoprofen tromethamine preparation, this method eliminates the need for expensive impurity standards, enabling qualitative and quantitative analysis of related substances in dexketoprofen tromethamine. This solves the quality control problem of dexketoprofen tromethamine preparations, facilitating quality control and ensuring drug safety.

[0029] The structural formulas of the relevant substances are as follows:

[0030]

[0031] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0032] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0033] Figure 1 Chromatogram of the spiked test solution for impurities in Example 1

[0034] Figure 2Chromatogram of the test solution in Example 2

[0035] Figure 3 Solvent chromatograms in specificity experiments

[0036] Figure 4 Chromatogram of blank excipient solution in specificity test

[0037] Figure 5 Chromatogram of the test solution in the specificity test Detailed Implementation

[0038] The raw materials and equipment used in the specific embodiments of the present invention are all known products, obtained by purchasing commercially available products.

[0039] Example 1: Detection of related substances in dexketoprofen tromethamine preparations

[0040] (1) Chromatographic conditions

[0041] Column: Octadecylsilane-bonded silica gel was used as the packing material (Waters XTERRA MS C18, 4.6 mm × 250 mm, 3.5 μm or equivalent column);

[0042] Mobile phase: phosphate buffer (68.0 g of potassium dihydrogen phosphate dissolved in water and diluted to 1000 ml, pH adjusted to 3.5 with phosphoric acid) - water (2:55) as mobile phase A; acetonitrile as mobile phase B;

[0043] Detection wavelengths: 210nm and 233nm (simultaneous acquisition); flow rate: 1ml / min; injection volume: 20μl; column temperature: 30℃;

[0044] Gradient elution procedure:

[0045]

[0046] (2) Solution preparation

[0047] Solvent: Take water, adjust the pH value to 3.0±0.3 with phosphoric acid to obtain a phosphoric acid solution, and mix the phosphoric acid solution with acetonitrile at a volume ratio of 60:40 to obtain the final product;

[0048] Test solution: Take dexketoprofen tromethamine tablets, grind them into a fine powder, accurately weigh an appropriate amount of the fine powder (equivalent to 25mg of dexketoprofen), place it in a 25ml brown volumetric flask, add 15ml of solvent, sonicate for 20 minutes, cool, then dilute to the mark with solvent, shake well, filter, and take the filtrate to obtain the test solution.

[0049] Stock solutions of impurity I, II, IV and V reference standards: Accurately weigh 6.8 mg each of impurity I, impurity II, impurity IV and impurity V reference standards, place them in 10 ml brown volumetric flasks, dissolve and dilute to the mark with acetonitrile, and shake well (680 μg / ml) to obtain the solution.

[0050] Impurity III reference standard stock solution: Accurately weigh 9.0 mg of impurity III reference standard (trifluoroacetate), place it in a 10 ml brown volumetric flask, dissolve and dilute to the mark with acetonitrile, and shake well (impurity III 680 μg / ml).

[0051] Impurity localization solution: Take 1 ml (680 μg / ml) of each of the stock solutions of impurity I, impurity II, impurity III, impurity IV, and impurity V, and place them in separate 10 ml brown volumetric flasks. Dissolve and dilute to the mark with solvent, and shake well (68 μg / ml); then take 1 ml of each and place them in separate 25 ml brown volumetric flasks. Dilute to the mark with solvent, and shake well (2.7 μg / ml).

[0052] Spiked impurity test solution: Accurately measure 2.5 ml each of the stock solutions of impurity I, impurity II, impurity III, impurity IV, and impurity V (680 μg / ml), place them in the same 50 ml brown volumetric flask, dilute to the mark with solvent, and shake well to prepare the mixed impurity stock solution. Take dexketoprofen tromethamine tablets, grind them into a fine powder, accurately weigh an appropriate amount of the fine powder (equivalent to 25 mg of dexketoprofen), place it in a 25 ml brown volumetric flask, add 15 ml of solvent, sonicate for 20 minutes, cool, accurately add 2 ml of the mixed impurity stock solution, dilute to the mark with solvent, shake well, filter, and collect the filtrate to obtain the test solution.

[0053] (3) Measurement

[0054] The test solution, impurity localization solution, and impurity spiked test solution are injected into the chromatograph, and the chromatograms are recorded.

[0055] (4) Qualitative and quantitative analysis of impurities

[0056] For impurity peaks in the chromatogram of the test solution, the peak areas of impurities I, II, and III were calculated using the area normalization method, with the peak areas calculated by multiplying the corrected peak areas (at a wavelength of 210 nm by a correction factor of 1.3) and the peak areas of impurities IV, V, and others (at a wavelength of 233 nm).

[0057] The relative retention times of impurities are shown in Table 1.

[0058] Table 1

[0059]

[0060] Note: RRT is the relative retention time of each impurity chromatographic peak and the dextroprofen chromatographic peak.

[0061] Example 2: Detection of related substances in dexketoprofen tromethamine preparations

[0062] (1) Chromatographic conditions

[0063] Column: Octadecylsilane-bonded silica gel was used as the packing material (Waters XTERRA MS C18, 4.6 mm × 250 mm, 3.5 μm or equivalent column);

[0064] Mobile phase: phosphate buffer (68.0 g of potassium dihydrogen phosphate dissolved in water and diluted to 1000 ml, pH adjusted to 3.5 with phosphoric acid) - water (2:55) as mobile phase A; acetonitrile as mobile phase B;

[0065] Detection wavelengths: 210nm and 233nm (simultaneous acquisition); flow rate: 1ml / min; injection volume: 20μl; column temperature: 30℃;

[0066] Gradient elution procedure:

[0067]

[0068] (2) Solution preparation

[0069] Solvent: Take water, adjust the pH value to 3.0±0.3 with phosphoric acid to obtain a phosphoric acid solution, and mix the phosphoric acid solution with acetonitrile at a volume ratio of 60:40 to obtain the final product;

[0070] Test solution: Take dexketoprofen tromethamine tablets (batch number 230601, stored at 40℃ / RH75% for 2 months), grind them into a fine powder, accurately weigh an appropriate amount of the fine powder (equivalent to 25mg of dexketoprofen), place it in a 25ml brown volumetric flask, add 15ml of solvent, sonicate for 20 minutes, cool, then dilute to the mark with solvent, shake well, filter, and take the filtrate to obtain the test solution;

[0071] (3) Measurement

[0072] Inject the test solution into the chromatograph and record the chromatogram.

[0073] (4) Qualitative and quantitative analysis of impurities

[0074] If impurity peaks are present in the chromatogram of the test solution, the peak areas of impurity I (RRT 1.27), impurity II (RRT 0.35), and impurity III (RRT 0.24) are calculated using the area normalization method, based on the corrected peak area (at a wavelength of 210 nm, multiplied by a correction factor of 1.3). The peak areas of impurity IV (RRT 2.10), impurity V (RRT 2.24), and other impurities are calculated based on their peak areas (at a wavelength of 233 nm).

[0075] The specific calculation formula is as follows:

[0076] At 210 nm, impurities I, II, and III are calculated as the impurities to be tested: (impurity peak area × 1.3) / [(impurity I peak area × 1.3) + (impurity II peak area × 1.3) + (impurity III peak area × 1.3) + main peak area + other impurity peak areas].

[0077] At 233nm, impurity IV, impurity V, and other impurities were used as analytes, and the peak area of ​​the analyte was calculated as follows: peak area of ​​analyte / (peak area of ​​impurity IV + peak area of ​​impurity V + peak area of ​​main peak + peak area of ​​other impurities).

[0078] The test results are shown in Table 2 and Figure 2 .

[0079] Table 2. Results of Impurity Content Determination in Dexketoprofen and Aminotriol Tablets

[0080]

[0081] Example 3: Detection of related substances in dexketoprofen tromethamine preparations

[0082] The detection conditions differ from those in Example 2: the mobile phase pH and column temperature are different.

[0083] (1) Chromatographic conditions

[0084] Column: Octadecylsilane-bonded silica gel was used as the packing material (Waters XTERRA MS C18, 4.6 mm × 250 mm, 3.5 μm or equivalent column);

[0085] Mobile phase: phosphate buffer (68.0 g of potassium dihydrogen phosphate dissolved in water and diluted to 1000 ml, pH adjusted to 4.0 with phosphoric acid) - water (2:55) as mobile phase A; acetonitrile as mobile phase B;

[0086] Detection wavelengths: 210nm and 233nm (simultaneous acquisition); flow rate: 1ml / min; injection volume: 20μl; column temperature: 50℃;

[0087] Gradient elution procedure:

[0088]

[0089] (2) Solution preparation

[0090] Solvent: Take water, adjust the pH value to 3.0±0.3 with phosphoric acid to obtain a phosphoric acid solution, and mix the phosphoric acid solution with acetonitrile at a volume ratio of 60:40 to obtain the final product;

[0091] Test solution: Take dexketoprofen tromethamine tablets (batch number 230601, stored at 40℃ / RH75% for 1 month), grind them into a fine powder, accurately weigh an appropriate amount of the fine powder (equivalent to 25mg of dexketoprofen), place it in a 25ml brown volumetric flask, add 15ml of solvent, sonicate for 20 minutes, cool, then dilute to the mark with solvent, shake well, filter, and take the filtrate to obtain the test solution;

[0092] (3) Measurement

[0093] Inject the test solution into the chromatograph and record the chromatogram.

[0094] (4) Limits

[0095] If impurity peaks are present in the chromatogram of the test solution, the peak areas of impurity I (RRT 1.27), impurity II (RRT 0.35), and impurity III (RRT 0.24) are calculated using the area normalization method, based on the corrected peak area (at a wavelength of 210 nm, multiplied by a correction factor of 1.3). The peak areas of impurity IV (RRT 2.10), impurity V (RRT 2.24), and other impurities are calculated based on their peak areas (at a wavelength of 233 nm).

[0096] The test results are shown in Table 3.

[0097] Table 3

[0098]

[0099] Example 4: Detection of related substances in dexketoprofen tromethamine preparations

[0100] The dextromethorphan tromethamine injection (batch number 23030114, stored at 40℃ / RH75% for 1 month) was tested according to the method in Example 2, and the results are shown in Table 4.

[0101] Table 4

[0102]

[0103]

[0104] Comparative Example 1

[0105] The difference from Example 1 lies in the pH value of the solvent. Specifically:

[0106] Solvent: Take water, adjust the pH value to 2.5 with phosphoric acid to obtain a phosphoric acid solution, and mix the phosphoric acid solution with acetonitrile at a volume ratio of 60:40 to obtain the final product.

[0107] Impurity spiked test solution I: Take dexketoprofen tromethamine tablets, grind them into a fine powder, accurately weigh an appropriate amount of the fine powder (equivalent to 25 mg of dexketoprofen), place it in a 25 ml brown volumetric flask, accurately add 2 ml of mixed impurity reference stock solution and 15 ml of solvent, sonicate for 20 minutes, cool, dilute to the mark with solvent, shake well, filter, and take the filtrate as impurity spiked test solution I. Inject impurity spiked test solution I multiple times at the same wavelength to examine the stability of the solution. The results are shown in Table 5.

[0108] Table 5. Stability of Spiked Test Solution I

[0109]

[0110] The results showed that when the solvent pH was 2.5, impurity III had poor stability in the solvent. After 12 hours, the deviation value exceeded +5%, making it impossible to accurately detect the content of related substances in dexketoprofen tromethamine.

[0111] Comparative Example 2

[0112] The difference from Example 1 lies in the pH value of the solvent. Specifically:

[0113] Solvent: Take water, adjust the pH value to 4.0 with phosphoric acid to obtain a phosphoric acid solution, and mix the phosphoric acid solution with acetonitrile at a volume ratio of 60:40 to obtain the final product.

[0114] Impurity spiked test solution II: Take dexketoprofen tromethamine tablets, grind them into a fine powder, accurately weigh an appropriate amount of the powder (equivalent to 25 mg of dexketoprofen), place it in a 25 ml brown volumetric flask, accurately add 2 ml of mixed impurity reference stock solution and 15 ml of solvent, sonicate for 20 minutes, cool, dilute to the mark with solvent, shake well, filter, and take the filtrate as impurity spiked test solution II. Inject impurity spiked test solution II multiple times at the same wavelength to examine the stability of the solution; the results are shown in Table 6.

[0115] Table 6. Stability of Spiked Test Solution II

[0116]

[0117]

[0118] The results showed that when the solvent pH was 4.0, impurity III had poor stability in the solvent. After 12 hours, the deviation value exceeded -5%, making it impossible to accurately detect the content of related substances in dexketoprofen tromethamine.

[0119] Comparative Example 3

[0120] The difference from Example 1 is that the test sample is dextromethorphan tromethamine tablets that have undergone strong light degradation, and the gradient elution program is different. Specifically:

[0121] Take dexketoprofen tromethamine tablets, grind them into a fine powder, and place an appropriate amount of the powder under light at 4500 Lx ± 500 Lx for 3 days. Accurately weigh an appropriate amount of the powder (equivalent to 25 mg of dexketoprofen), place it in a 25 ml brown volumetric flask, add 15 ml of solvent, sonicate for 20 minutes, cool, dilute to the mark with phosphoric acid solution, shake well, filter, and take the filtrate as the test solution for photodegradation. Inject the sample according to the following gradient.

[0122] Gradient elution procedure:

[0123]

[0124] The results showed that seven impurities were detected in the strongly degrading test sample, among which impurity (t) R =51.546min) and impurities (t R The resolution of the detection method (51.658 min) was only 0.11, which means the specificity of the detection method could not meet the requirements.

[0125] Experimental Example 1: Methodological Validation

[0126] Verification basis

[0127] This validation was conducted in accordance with the requirements of the 2020 edition of the Chinese Pharmacopoeia, validating the following parameters of the related substances method for dexketoprofen tromethamine tablets: specificity, accuracy, and limit of quantitation / limit of detection. All results met the acceptable criteria.

[0128] 1. Exclusivity

[0129] Solution preparation

[0130] Solvent: Phosphoric acid solution (take water, adjust the pH to 3.0±0.3 with phosphoric acid) - acetonitrile (60∶40).

[0131] Blank excipient solution: Weigh an appropriate amount of blank excipient for the dextromethorphan tromethamine preparation according to the prescription ratio, accurately weigh it, place it in a 100ml volumetric flask, add 60ml of solvent, sonicate for 20 minutes, cool, dilute to the mark with solvent, shake well, filter, and collect the filtrate.

[0132] Test solution: Accurately weigh an appropriate amount of dexketoprofen tromethamine preparation (equivalent to 25 mg of dexketoprofen), place it in a 25 ml brown volumetric flask, add 15 ml of solvent, sonicate for 20 minutes, cool, dilute to the mark with solvent, shake well, filter, and collect the filtrate.

[0133] Measurement

[0134] Take blank solution (solvent), blank excipient solution and test solution in sequence, inject them into the liquid chromatograph and record the chromatogram.

[0135] Results: Neither the solvent nor the blank excipient interfered with the main component peaks or impurity peaks, meeting acceptable standards (see Table 7). Figure 3-5 ).

[0136] Table 7 Specificity Results

[0137] name <![CDATA[Retention time of main peak t R (min)]]> Results (whether interference exists) Attached Figure solvent No chromatographic peak No interference observed Figure 3 Blank excipient solution No chromatographic peak No interference observed Figure 4 Test solution 18.0 No interference observed Figure 5

[0138] 2. Accuracy (recovery rate of 5 impurities)

[0139] Take an appropriate amount of dexketoprofen tromethamine preparation, add an appropriate amount of known impurity reference standard, and prepare accuracy solutions at three concentration levels of 10%, 100%, and 150% of the limit concentration. Take three portions of each concentration level and calculate the recovery rate for each.

[0140] Calculation formula:

[0141] The results at concentration levels of 10%, 100%, and 150% are as follows:

[0142] The recoveries of impurities I, II, III, IV, and V were 101%–104%, 102%–107%, 95%–98%, 102%–108%, and 101%–104%, respectively, with RSDs of 1.15%–2.06%. The accuracy verification results met the acceptable criteria.

[0143] 3. Limit of Quantification / Limit of Detection

[0144] Limit of Quantitation (LOQ) test solution: Prepare a mixed solution with a concentration of approximately 0.008% by taking appropriate amounts of impurities I, II, III, IV, and V, and then inject the solution for determination. The LQ results are as follows:

[0145] The limits of quantitation for impurities I, II, III, IV and V are 0.014%, 0.026%, 0.026%, 0.027% and 0.027%, respectively, all <0.03%. At this point, the S / N of each component's chromatographic peak is >10, which meets the acceptable standard.

[0146] Detection limit test solution: Prepare a mixed solution with a concentration of approximately 0.04–0.08 μg / ml by taking appropriate amounts of impurity I, impurity II, impurity III, impurity IV, and impurity V, and inject the solution for determination. The detection limit results are shown in Table 8.

[0147] Table 8 Detection Limit Results

[0148]

[0149]

[0150] Limit of detection: The S / N ratios of the chromatographic peaks of impurities I, II, III, IV and V in the solution were 8.1, 6.0, 5.8, 5.2 and 6.7, respectively, all >3, which meets the acceptable standard.

[0151] In summary, this invention uses a specific solvent to treat dexketoprofen tromethamine preparations as a test solution for high-performance liquid chromatography (HPLC) detection. With the aid of a specific chromatographic column and chromatographic conditions, it can simultaneously separate relevant substances within 60 minutes. The method is unaffected by solvents or excipients and can analyze relevant substances at a level of 100 ppm in a single experiment. This solves the quality control problem of dexketoprofen tromethamine preparations and is beneficial for quality control of these preparations.

Claims

1. A method for detecting related substances in dexketoprofen tromethamine preparations, characterized in that: The steps include: taking the sample to be tested, and detecting it using high-performance liquid chromatography (HPLC) under the following chromatographic conditions: Column: Packed with octadecylsilane-bonded silica gel; Mobile phase: phosphate buffer and water as mobile phase A; acetonitrile as mobile phase B; The detection wavelengths are 210nm and 233nm; Gradient elution procedure:

2. The detection method as described in claim 1, characterized in that: The steps include: ① Preparation of test solution: Take the sample to be tested, add solvent to dissolve it, and the solution is obtained; ② The test solution was analyzed by high performance liquid chromatography and the chromatogram was recorded. The chromatographic conditions were as follows: the column was a Waters XTERRAMS C18, 4.6 mm × 250 mm, 3.5 μm or a column with equivalent performance; the mobile phase A was phosphate buffer and water in a volume ratio of 2:

55.

3. The detection method as described in claim 2, characterized in that: In step ①, the mass-to-volume ratio of the sample to the solvent is equivalent to 10-25 mg of dextroprofen: 25 ml of solvent.

4. The detection method as described in claim 2 or 3, characterized in that: The solvent is a mixed solution of an aqueous solution of phosphoric acid with a pH of 3.0 ± 0.3 and acetonitrile.

5. The detection method as described in claim 4, characterized in that: The volume ratio of the phosphoric acid aqueous solution to acetonitrile is 50-90:10-50, preferably 60:

40.

6. The detection method as described in claim 1 or 2, characterized in that: The phosphate buffer in the mobile phase A contains 68.0 g of potassium dihydrogen phosphate per 1 L, and the pH is adjusted to 3.5 ± 0.5 with phosphoric acid.

7. The detection method as described in claim 1, characterized in that: The chromatographic conditions also include a flow rate of 0.5–1.8 ml / min; a column temperature of 25–50 °C; an injection volume of 10–50 μl, preferably a flow rate of 1.0 ml / min; a column temperature of 30–50 °C; and an injection volume of 20 μl.

8. The detection method according to any one of claims 1 to 7, characterized in that: The chromatogram of the sample to be tested shows chromatographic peaks of related substances, and the content of related substances is calculated by the area normalization method; the related substances are selected from at least one of the following impurities: Impurity I: Impurity II: Impurity III: Impurity IV: Impurity V:

9. The detection method as described in claim 8, characterized in that: The relative retention times of the related substances chromatographic peaks and the dexketoprofen tromethamine chromatographic peaks were 1.27 for impurity I, 0.35 for impurity II, 0.24 for impurity III, 2.10 for impurity IV, and 2.24 for impurity V, respectively.

10. The detection method as described in claim 8 or 9, characterized in that: The contents of impurity I, impurity II and impurity III are calculated by multiplying the peak area of ​​the chromatographic peak at a wavelength of 210 nm by a correction factor of 1.3; the contents of impurity IV, impurity V and other impurities are calculated by the peak area at a wavelength of 233 nm.

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