Quality detection method of diclofenac sodium lidocaine hydrochloride injection

Abstract

The invention relates to a quality detection method of diclofenac sodium lidocaine hydrochloride injection, and belongs to the field of medicine detection. The invention provides a quality detection method of a diclofenac sodium lidocaine hydrochloride injection. According to the method, a large amount of screening development is carried out on the basis of a legal standard, the specificity of known impurities is investigated, the specificity of unknown impurities is investigated, and the related substances in the diclofenac sodium lidocaine hydrochloride injection are accurately and exclusively detected; a reasonable and scientific detection method is provided for release of diclofenac sodium lidocaine hydrochloride injection manufacturers, a practical basis is provided for improvement of quality standards of related substances of the diclofenac sodium lidocaine hydrochloride injection, and a guarantee is provided for clinical medication safety. The method is low in detection efficiency, specificity, operability and detection cost, and the quality control is obviously superior to that of currently reported literature methods and legal standards.

Description

Technical Field

[0001] The invention relates to a quality detection method for diclofenac sodium lidocaine hydrochloride injection, and belongs to the field of drug detection. Background Art

[0002] The dosage form of diclofenac sodium and lidocaine injection is injection, with a specification of 2ml: diclofenac sodium 75mg, lidocaine hydrochloride 20mg. Diclofenac sodium is a non-steroidal anti-inflammatory drug (NSAIDs), and is one of the analgesics with the most clinical evidence and the largest prescription volume. Lidocaine belongs to the amide local anesthetic, and its combination preparation is a commonly used clinical treatment for musculoskeletal pain, mainly used for severe inflammation or degenerative rheumatic disease.

[0003] The structural formula of diclofenac sodium is as follows:

[0004] The structural formula of lidocaine hydrochloride is as follows:

[0005] According to the prescription information retrieved, in addition to the two main ingredients clearly identified, diclofenac sodium and lidocaine hydrochloride injection also contains other corresponding excipients: propylene glycol, polyethylene glycol, and edetate disodium acetylcysteine.

[0006] There are safety issues with diclofenac sodium lidocaine injection. According to literature reports, the adverse reactions of diclofenac sodium lidocaine hydrochloride injection include allergic reactions, laryngeal edema, hyperthermia, and anaphylactic shock (Li Wei, et al., Overview of adverse reactions of diclofenac sodium lidocaine hydrochloride injection, Chinese Journal of Drug Abuse Prevention and Treatment, Vol. 25, No. 1, 2019). Quality control and ensuring clinical safety are particularly important. Information on the quality standard of diclofenac sodium lidocaine injection found: ① China (ChP), Europe (EP) and the United States (USP) have published standards for diclofenac sodium and lidocaine hydrochloride raw materials; ② No country or region has published a single-component diclofenac sodium injection standard; ③ The Chinese Pharmacopoeia has published a single-component lidocaine hydrochloride injection standard, and other countries and regions have not published relevant standards; ④ The import registration standard publishes the standard for diclofenac sodium lidocaine hydrochloride injection.

[0007] Among the published statutory standards, according to the current standards and the actual needs of quality control: ① Diclofenac sodium contains 6 impurities A / B / C / D / E / F published by EP, among which the degradation impurity A that will continue to increase during the production and storage of raw materials and preparations needs to be paid special attention to; ② Lidocaine hydrochloride contains 10 impurities A / B / C / D / E / F / G / H / I / J published by EP, among which impurity A needs to be paid special attention to. According to the "Scientific Review of the Risks of Nitrosamine Impurities in Human Medicines" issued by EMA, this impurity contains a warning structure that requires attention, and it can be considered as a general teratogenic impurity that requires special attention and control.

[0008] The literature on the quality inspection of diclofenac sodium and lidocaine hydrochloride injection at present includes: Zhang Li et al., HPLC determination of diclofenac sodium and lidocaine hydrochloride in compound diclofenac sodium injection, chromatographic column: Shim-pack CLC-0DS (M) column 4.6 liquid, each mm × 150 mm, mobile phase: acetate buffer (ammonium acetate 5.2g and triethylamine 7.4mL added with water to 1000mL, adjusted to pH 4.0 with glacial acetic acid)-methanol (38:62), flow rate 1.0mL min -1 , detection wavelength 235nm, injection volume 20L. This document detects the content of diclofenac sodium and lidocaine hydrochloride, and does not detect the impurities therein.

[0009] Wu Liangyong, et al., Research ideas on impurity control of diclofenac sodium and lidocaine hydrochloride injection, Chinese Pharmaceutical Standards, 2022, 23 (6) An HPLC method for determining impurities in diclofenac sodium and lidocaine hydrochloride injection was established, and the key points of impurity control of compound preparations were analyzed. Methods: Kromasil C18 (4.6 mm × 250 mm, 5 μm) chromatographic column was used, methanol-4% glacial acetic acid solution (65:35) was used as the mobile phase, and the detection wavelength was 254 nm to determine the related substances of diclofenac sodium; CNWAthena C 18 (4.6mm × 250mm, 5μm) as the chromatographic column, phosphate buffer (1mol·L -1 Sodium dihydrogen phosphate solution 1.3mL and 0.5mol·L -1 32.5mL of disodium hydrogen phosphate solution was diluted to 1000mL with water and the pH was adjusted to 8.0 with 10% phosphoric acid)-acetonitrile (50:50) as the mobile phase and the detection wavelength was 230nm to determine the known impurity 2,6-dimethylaniline in lidocaine hydrochloride.

[0010] Li Chunying, et al., Determination of related substances in diclofenac sodium and lidocaine hydrochloride injection by HPLC, Northern Pharmacy 2016, Vol. 13, No. 9, Establishment of HPLC method for determination of related substances in compound preparation diclofenac sodium and lidocaine hydrochloride injection. Methods: Reverse phase high performance liquid chromatography was used to calculate the amount of related substances in diclofenac sodium and lidocaine hydrochloride injection by self-control method.

[0011] According to current regulations, the standard quality control of diclofenac sodium and lidocaine hydrochloride injection has the following key points (or difficulties): ① The method has considerable specificity and can locate the 16 impurities included in the standard and accurately quantify two special impurities; ② The injection matrix is ​​complex and contains a large number of organic excipients, so the method needs to be quite durable and can ensure large-scale testing and detection efficiency of samples; ③ Diclofenac sodium and lidocaine hydrochloride may produce other unknown degradation impurities with other coexisting excipients under wet, hot and light conditions. The developed method can not only control known impurities, but also have a certain resolution for unknown impurities.

[0012] It should be further explained that although the import registration standard has established the quality standard for diclofenac sodium and lidocaine hydrochloride injection, the standard included therein is relatively early, and three sets of methods are used to control the detection of impurities in the injection, and the control requirements are low. It can no longer meet the current quality and safety requirements of relevant national departments for the registration of injections on the market, so it has no actual reference value, and it is necessary to develop quality inspection standards for injections. Summary of the invention

[0013] The invention provides a quality detection method for diclofenac sodium and lidocaine hydrochloride injection.

[0014] The invention provides a quality detection method for diclofenac sodium lidocaine hydrochloride injection. The method detects impurities in the diclofenac sodium lidocaine hydrochloride injection by HPLC, wherein the impurities include diclofenac sodium impurity A, diclofenac sodium impurity B, diclofenac sodium impurity C, diclofenac sodium impurity D, diclofenac sodium impurity E, diclofenac sodium impurity F, lidocaine hydrochloride impurity A, lidocaine hydrochloride impurity B, lidocaine hydrochloride impurity C, lidocaine hydrochloride impurity D, lidocaine hydrochloride impurity E, lidocaine hydrochloride impurity F, lidocaine hydrochloride impurity G, lidocaine hydrochloride impurity H, lidocaine hydrochloride impurity I and lidocaine hydrochloride impurity J. The chromatographic conditions are: Chromatographic column: Thermo GOLD C18 4.6*250mm 5μm; Mobile phase: Mobile phase A is acetonitrile-phosphate buffer; mobile phase B is acetonitrile-water solution; Column temperature: 40°C; Flow rate: 1.2 ml / min; Detection wavelength: 230nm; Injection volume: 20 μl; Elution method: gradient elution, elution conditions are as follows: Time min A% B% 0 90 10 45 50 50 55 20 80 56 90 10 65 90 10 The steps include: a. Preparation of test solution: Accurately measure 1 ml of diclofenac sodium and lidocaine hydrochloride injection, place in a 10 ml volumetric flask, and dilute to the mark with 10% acetonitrile; b. Preparation of impurity control: Weigh lidocaine hydrochloride impurities A / B / C / D / E / F / G / H / I / J, add a small amount of acetonitrile to dissolve, and then add 10% acetonitrile to prepare an impurity reference substance mother solution; weigh diclofenac sodium impurities A / B / C / D / E / F, add a small amount of acetonitrile to dissolve, and then add 10% acetonitrile to prepare an impurity reference substance mother solution; weigh lidocaine hydrochloride bulk drug and diclofenac sodium bulk drug into the same volumetric flask, add an appropriate amount of impurity reference substance mother solution to prepare a mixed solution containing 0.1% of each impurity relative to lidocaine hydrochloride, wherein the concentration of lidocaine hydrochloride is 2.5 mg / ml, and a mixed solution containing 0.1% of each impurity relative to diclofenac sodium, wherein the concentration of diclofenac sodium is 7.5 mg / ml; c. Preparation of control solution: Accurately measure 1 ml of the test solution and dilute it to 100 ml with 10% acetonitrile; d. Detect according to the HPLC chromatographic conditions.

[0015] Wherein, the pH of the acetonitrile-phosphate buffer is adjusted to 8.0 with sodium hydroxide.

[0016] Among them, the retention time of the detected impurities is: Diclofenac Impurity E: 8.778 min, Lidocaine Hydrochloride Impurity C: 10.057 min, Lidocaine Hydrochloride Impurity B: 10.832 min, Lidocaine Hydrochloride Impurity D: 15.329 min, Lidocaine Hydrochloride Impurity H: 18.3 min, Lidocaine Hydrochloride Impurity A: 20.557 min, Lidocaine Hydrochloride Impurity G: 22.094 min, Diclofenac Impurity D: 25.694 min, Lidocaine Hydrochloride Impurity E: 28.923 min, Diclofenac Impurity A: 41.13 min, Lidocaine Hydrochloride Impurity F: 43.995 min, Diclofenac Impurity C: 44.584 min, Lidocaine Hydrochloride Impurity I: 45.982 min, Lidocaine Hydrochloride Impurity J: 46.619 min. min, diclofenac impurity F: 49.393 min, diclofenac impurity B: 52.031 min, and the retention time fluctuated by 0.4 min.

[0017] The beneficial effects of the present invention are: The present invention achieves accurate and exclusive detection of related substances in diclofenac sodium and lidocaine hydrochloride injection by conducting a large number of screening and development on the basis of statutory standards, investigating the specificity of known impurities and unknown impurities, providing a reasonable and scientific detection method for diclofenac sodium and lidocaine hydrochloride injection manufacturers to release, providing a realistic basis for improving the quality standards of related substances in diclofenac sodium and lidocaine hydrochloride injection, and providing a guarantee for the safety of clinical medication. The method is significantly better than the currently reported literature methods and statutory standards in terms of detection efficiency, specificity, operability, low detection cost and quality control. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a typical chromatogram of quality detection of diclofenac sodium and lidocaine hydrochloride injection of the present invention; Figure 2 is the blank solution chromatogram; Figure 3 is the chromatogram of blank excipient solution; Figure 4 Reproduce a typical chromatogram for the EP lidocaine hydrochloride API method; Figure 5 Develop typical chromatograms for related substance gradient methods; Figure 6 This is a typical chromatogram of gradient elution 2; Figure 7 This is a typical chromatogram of gradient elution 3; Figure 8 Typical chromatogram for gradient elution 4; Fig. 9 A typical chromatogram for gradient elution 5; Fig.10 Typical chromatogram for gradient elution 6; Fig.11 Typical chromatogram for gradient elution 7. DETAILED DESCRIPTION

[0019] Example 1 Quality testing method for diclofenac sodium and lidocaine hydrochloride injection of the present invention The impurities detected by the quality detection method of the present invention are as follows:

[0020] Diclofenac Sodium Impurity A (China Food and Drug Inspection Institute)

[0021] Diclofenac Sodium Impurity B (China Food and Drug Inspection Institute)

[0022] Diclofenac Sodium Impurity C (China Food and Drug Inspection Institute)

[0023] Diclofenac Sodium Impurity D (China Food and Drug Inspection Institute)

[0024] Diclofenac Sodium Impurity E (China Food and Drug Inspection Institute)

[0025] Diclofenac Sodium Impurity F (China Food and Drug Inspection Institute)

[0026] Lidocaine Hydrochloride Impurity A (QCS Standard Material Research and Development Center)

[0027] Lidocaine Hydrochloride Impurity B (QCS Standard Material Research and Development Center)

[0028] Lidocaine Hydrochloride Impurity C (QCS Standard Material Research and Development Center)

[0029] Lidocaine Hydrochloride Impurity D (QCS Standard Material Research and Development Center)

[0030] Lidocaine Hydrochloride Impurity E (QCS Standard Material Research and Development Center)

[0031] Lidocaine Hydrochloride Impurity F (QCS Standard Material Research and Development Center)

[0032] Lidocaine Hydrochloride Impurity G (QCS Standard Material Research and Development Center)

[0033] Lidocaine Hydrochloride Impurity H (QCS Standard Material Research and Development Center)

[0034] Lidocaine Hydrochloride Impurity I (QCS Standard Material Research and Development Center)

[0035] Lidocaine Hydrochloride Impurity J (QCS Standard Material Research and Development Center) Test solution: Take 1 ml of the preparation solution (manufacturer: Teva, listed country: Czech Republic), add 10% acetonitrile and dilute to 10 ml.

[0036] Control solution (used to calculate the impurity content in the finished product): Take 1 ml of the test solution and dilute it to 100 ml with 10% acetonitrile.

[0037] Impurity spike solution: weigh lidocaine hydrochloride impurities A / B / C / D / E / F / G / H / I / J, add a small amount of acetonitrile to dissolve, and then add 10% acetonitrile to prepare an impurity reference substance mother solution; weigh diclofenac sodium impurities A / B / C / D / E / F, add a small amount of acetonitrile to dissolve, and then add 10% acetonitrile to prepare an impurity reference substance mother solution; weigh lidocaine hydrochloride bulk drug and diclofenac sodium bulk drug into the same volumetric flask, add an appropriate amount of impurity reference substance mother solution to prepare a mixed solution containing 0.1% of each impurity relative to lidocaine hydrochloride, wherein the concentration of lidocaine hydrochloride is 2.5 mg / ml, and a mixed solution containing 0.1% of each impurity relative to diclofenac sodium, wherein the concentration of diclofenac sodium is 7.5 mg / ml.

[0038] Chromatographic conditions: Chromatographic column: Thermo GOLD C18 4.6*250mm 5μm; Mobile phase: Mobile phase A is acetonitrile-phosphate buffer; mobile phase B is acetonitrile-water solution; Mobile phase A: 4.85g / L potassium dihydrogen phosphate buffer (adjust pH to 8.0 with sodium hydroxide)-acetonitrile (97:3); Mobile phase B: take 970ml of acetonitrile, add 30ml of water and mix well.

[0039] Elution method: gradient elution, elution conditions see Table 1: Column temperature: 40°C; Flow rate: 1.2 ml / min; Detection wavelength: 230 nm; Injection volume: 20 μl; Solution used: impurity spike solution; Blank solution and diluent: 10% acetonitrile.

[0040] Table 1 Gradient elution conditions T / min A% B% 0 90 10 45 50 50 55 20 80 56 90 10 65 90 10 The specificity of the method for known and unknown impurities was investigated by simultaneously injecting samples spiked with impurities and samples degraded by humidity.

[0041] Results: ① Blank solution and blank auxiliary material solution did not interfere with the detection. The known impurities had good separation, the peak shape was good, and the tailing was low, which met the requirements for accurate determination of specific impurities and general impurity positioning. The results are shown in Table 2 and the typical chromatograms are shown in Figure 1 , blank solution chromatogram is shown in Figure 2 , the chromatogram of blank excipient solution is shown in Figure 3 ; ② The possible degradation impurities in the moderately degraded samples did not interfere with the detection of specific impurities and main peaks.

[0042] Table 2 Results of investigation on specificity of known impurities Impurity Name Retention time min Separation Number of plates Tailing Factor SL-E 8.778 / 29281 0.9 LD-C 10.057 5.73 27811 1.18 LD-B 10.832 2.06 7196 1.09 LD-D 15.329 11.38 48373 1.06 LD-H 18.3 9.94 52463 1 LD-A 20.557 6.87 59035 0.99 LD-G 22.094 4.71 80241 1.04 Diclofenac Sodium 24.664 7.86 82801 1.64 SL-D 25.694 3.49 175766 0.98 LD-E 28.923 11.99 155607 1 Unknown impurities 35.248 20.84 201708 1.03 Lidocaine 37.568 8.72 474297 1.3 SL-A 41.13 12.54 219974 0.96 LD-F 43.995 7.86 217705 1.02 SL-C 44.584 1.55 212374 1.16 LD-I 45.982 3.62 231014 1 LD-J 46.619 1.67 237947 1 SL-F 49.393 8.12 430495 1 SL-B 52.031 9.6 700407 1.01 A set of detection methods for the accurate, efficient, reliable and stable determination of related substances in diclofenac sodium and lidocaine hydrochloride injection was established by HPLC.

[0043] Example 2 Condition screening test of the detection method of the present invention During the early development, the inventor first compared the statutory standards of various countries' pharmacopoeias, and then combined the properties of diclofenac sodium and lidocaine hydrochloride compounds and the information related to known impurities related to the main components, and inferred that the substances related to lidocaine hydrochloride raw materials included in the EP have greater development potential.

[0044] 1. EP lidocaine hydrochloride API method reproduction The inventor intends to use a DAD detector and a Waters C18 chromatographic column, 4.6 mm*250 mm*5 μm for method development. The chromatographic conditions of this experiment are shown in Table 3.

[0045] Table 3 Chromatographic conditions project content Chromatographic columns Waters C18, 4.6mm*150mm*5μm Mobile phase Phosphate buffered saline-acetonitrile = 70-30 Elution method Isocratic elution Column temperature (℃) 30 Detection wavelength (nm) 230 Injection volume (μl) 20 Sample plate temperature (°C) 8 Inspection samples Lidocaine hydrochloride related impurities spiked solution In this test example, the solution was prepared as follows: Mobile phase: 4.85 g / L potassium dihydrogen phosphate buffer (adjust pH to 8.0 with sodium hydroxide)-acetonitrile (70:30) Blank solution and diluent: 30% acetonitrile.

[0046] Inspection samples: Weigh lidocaine hydrochloride impurities A / B / C / D / E / F / G / H / I / J, add a small amount of acetonitrile to dissolve, and then add 30% acetonitrile to prepare the impurity reference substance mother solution; weigh lidocaine hydrochloride raw material into a volumetric flask, add an appropriate amount of impurity reference substance mother solution to prepare a mixed solution containing 0.1% of each impurity relative to lidocaine hydrochloride, in which the concentration of lidocaine hydrochloride is 5 mg / ml.

[0047] The experimental process and results are shown in Figure 4:①The elution time of each impurity of lidocaine is between 2min and 12min, and the elution time of the main peak is about 25min; ②The system of this method is a phosphate buffer system with pH 8.0. According to the chemical properties of diclofenac sodium (it is a pH-dependent raw material drug, insoluble in an acidic environment and soluble in an alkaline environment), this system is compatible with diclofenac sodium-related impurities; ③The elution time of each peak of this method is relatively scattered, and it is judged that this method has strong elution selectivity, which provides possible time and space conditions for the separation and positioning of a total of 16 impurities; ④The detection method of related substances of diclofenac injection can be optimized based on this method.

[0048] 2. Development of gradient method for related substances in injection Combined with the analysis of the impurity properties of diclofenac sodium and lidocaine hydrochloride, the isocratic method was gradient developed on the basis of item 1 of this example.

[0049] Chromatographic conditions: Chromatographic column: Waters C18, 4.6mm*150mm*5μm; Mobile phase: Mobile phase A is acetonitrile-phosphate buffer; Mobile phase B is acetonitrile-water solution Column temperature: 30°C; Detection wavelength: 230 nm; Injection volume: 20 μl; Sample pan temperature: 8°C; Test sample concentration: 0.1 mg / ml; Investigation sample: impurity spiked solution.

[0050] Table 4 Gradient elution conditions T / min A% B% 0 70 30 15 50 50 25 50 50 25.1 70 30 35 70 30 In this test example, the solution was prepared as follows: Mobile phase A: 4.85 g / L potassium dihydrogen phosphate buffer (adjusted to pH 8.0 with sodium hydroxide)-acetonitrile (97:3); mobile phase B: 97% acetonitrile.

[0051] Blank solution and diluent: 10% acetonitrile.

[0052] Inspection samples: Weigh lidocaine hydrochloride impurities A / B / C / D / E / F / G / H / I / J, add a small amount of acetonitrile to dissolve, and then add 30% acetonitrile to prepare an impurity reference substance mother solution; weigh diclofenac sodium impurities A / B / C / D / E / F, add a small amount of acetonitrile to dissolve, and then add 30% acetonitrile to prepare an impurity reference substance mother solution; weigh lidocaine hydrochloride bulk drug and diclofenac sodium bulk drug into the same volumetric flask, add an appropriate amount of impurity reference substance mother solution to prepare a mixed solution containing 0.1% of each impurity relative to lidocaine hydrochloride, wherein the concentration of lidocaine hydrochloride is 2.5 mg / ml, and a mixed solution containing 0.1% of each impurity relative to diclofenac sodium, wherein the concentration of diclofenac sodium is 7.5 mg / ml.

[0053] The experimental process and results are shown in Figure 5 : ① Through the relevant methods of EP lidocaine, the isocratic was changed to gradient for elution, the maximum organic term ratio was about 50% acetonitrile, and a total of 12 impurities were located. It was judged that 4 impurities overlapped or failed to elute in the system; ② In this method, diclofenac sodium elutes at 12 minutes and lidocaine at 18 minutes. Based on the properties of the main components and impurities, it was judged that the impurities introduced by the two main components had enough space for separation, so the optimization could continue under this system; ④ Under this condition, the main interference existed in 2 minutes to 10 minutes. Therefore, the method of optimizing the gradient reduced the initial proportion of the mobile phase and examined the elute situation of 16 impurities and two main components at different elution rates.

[0054] 3. Further development of gradient methods Based on the judgment in item 2, further optimize the elution procedure.

[0055] Table 5 Chromatographic conditions project content Chromatographic columns Waters C18, 4.6mm*150mm*5μm Mobile phase Mobile phase A was acetonitrile-phosphate buffer; mobile phase B was acetonitrile-water solution Elution method Gradient elution Column temperature (℃) 30 Detection wavelength (nm) 230 Injection volume (μl) 20 Flow rate (ml / min) 1.0 Sample plate temperature (°C) 8 Test sample concentration (mg / ml) 0.1 Inspection samples Impurity spike solution Table 6 Gradient elution conditions

[0056] In this test example, the mobile phase and solution used are the same as those shown in item 2.

[0057] The experimental process and results are shown in Figure 6-Figure 11 : ① Gradient condition 2: Based on item 2, the initial ratio is reduced, and the retention time of each peak is delayed; each peak has a separation trend, and the initial ratio or the gradient change rate is further considered; ② Gradient condition 3: Compared with gradient condition 2, there is almost no difference in the peak appearance; ③ Gradient condition 4: further reduce the initial ratio, delay the main peak to 14min, and the main peak to 20min; ④ Gradient condition 5: segmented elution was performed based on gradient 2. There was an interference peak before the main peak of diclofenac sodium, and the retention time of lidocaine was delayed to about 20 minutes; ⑤ Gradient condition 6: Further optimized on the basis of gradient 4, the known peaks detected have better peak shapes; the separation of each peak is good; through positioning, only the dichloro impurity E overlaps with the main peak of lidocaine, and the remaining impurities can be located and accurately detected; the next step of optimization is carried out by selecting the chromatographic column; when the initial organic phase ratio is increased from 10% to 50% within 45 minutes, the impurities have a good separation effect.

[0058] ⑥ Gradient condition 7: For gradient condition 6, the segments with impurity interference were optimized. After optimization, all 16 diclofenac sodium and lidocaine hydrochloride related sites were located. Among them, the worst separation between impurities and between impurities and main peaks was 1.2 (lidocaine impurity A and diclofenac impurity G), which basically met the requirements of specificity. However, lidocaine impurity A is a base toxic impurity, and the separation needs to be improved for accurate quantification.

[0059] In summary, the gradient screening test shows that the dichlorvos and lidocaine impurities can be completely separated by adjusting the organic phase gradient increase rate at an initial ratio of 10%, 20%, and 30%. However, the column efficiency of the chromatographic column decreased significantly after gradient screening, which is speculated to be directly related to the complex composition and high concentration of the sample. In order to further improve the durability, a series of screening of the chromatographic column of the method was carried out, and the screening target was to use a longer specification C18 chromatographic column.

[0060] 4. Durability inspection-chromatographic column screening Based on the third item "Gradient elution 7", further screening for more durable and cheaper chromatographic columns, the currently available Waters C 18 The price of the column is about RMB 8,000 per column. If you choose Thermo GOLD column (price is about RMB 4,000 per column), the length of the column will increase, and the peak elution time of each peak will inevitably be extended, and the selectivity will be better in theory. But at the same time, there may be strongly retained substances that cannot be eluted in the column. Therefore, on the basis of "gradient elution 7", the flow rate is increased to 1.2ml / min, and at the same time, in the high-proportion organic phase washing stage after 45 minutes, the organic phase ratio is further increased, in order to not change the peak elution situation before 45 minutes, while being able to elute the strongly retained substances in the column, extend the service life of the column, enhance the durability of the method, and significantly reduce the detection cost.

[0061] The chromatographic conditions were as follows: Chromatographic column: Thermo GOLD C18 4.6*250mm 5μm; Mobile phase: Mobile phase A is acetonitrile-phosphate buffer; mobile phase B is acetonitrile-water solution; Elution method: gradient elution, see Table 7; Column temperature: 40°C; Flow rate: 1.2 ml / min; Detection wavelength: 230 nm; Injection volume: 20 μl; Solution used: impurity spike solution; See Table 7 below.

[0062] Table 7 Gradient elution conditions T / min A% B% 0 90 10 45 50 50 55 20 80 56 90 10 65 90 10 In this test example, the solutions are the same as those in item 2.

[0063] The experimental process and results are shown in Figure 1 :① 16 impurities and 2 main components were completely detected; ② The worst separation between adjacent impurities and impurities, and between impurities and main peaks was 1.03 (lido impurity F and dichloro impurity C); ③ The separation between lido impurity A and the previous and next impurities were 7.07 and 3.54, respectively; the separation between dichloro impurity A and the previous and next peaks were 9.2 and 8.02, respectively; ④ This chromatographic condition fully meets the requirements for the positioning of known impurities and the accurate quantification of special impurities; ⑤ Under this chromatographic condition, it is planned to further reduce the concentration of the test sample to reduce the matrix interference without affecting the normal detection of impurities.

[0064] 5. Durability test - test sample concentration The chromatographic conditions were the same as those in item 4. When injecting samples, 10 / 20 / 50 μl of sample were used respectively.

[0065] Sample used: 1 homemade stability sample (2 ml, 25 mg / 75 mg), diluted 10 times with 10% acetonitrile.

[0066] Results: ①There was no significant change in the number of impurities detected when injecting 10μl compared with 20μl; ②When injecting 50μl, the peak was seriously overloaded; ③The injection volume was selected as 20μl.

[0067] 6. Durability inspection-detection wavelength The chromatographic conditions are the same as those in item 4.

[0068] Sample used: 1 homemade stability sample (2 ml, 25 mg / 75 mg), diluted 10 times with 30% acetonitrile.

[0069] Different detection wavelengths have a significant impact on the results of impurity detection. The detection wavelength of diclofenac sodium in the legal standard is 254nm, while the detection wavelength of lidocaine hydrochloride is 230nm, which is quite different. Therefore, firstly, a full wavelength scan was performed on each known impurity to determine the maximum absorption wavelength of the known impurities as shown in Table 8 below. It was determined that there were cross-overlapping parts between the absorption spectra of each impurity of lidocaine and each impurity of diclofenac sodium.

[0070] Table 8 Maximum absorption wavelength of known impurities

[0071] Secondly, the stability samples (test solutions with higher impurity content) were tested and the impurity content at different wavelengths was calculated.

[0072] Test results: The amount and number of impurities detected at 230nm wavelength were greater than those at 254nm wavelength, and the amount of impurities increased significantly. It is speculated that at 230nm wavelength, more lidocaine impurities were mainly detected, so the final selected wavelength was 230nm.

Claims

1. A quality detection method for diclofenac sodium and lidocaine hydrochloride injection, characterized in that: The method detects impurities in diclofenac sodium and lidocaine hydrochloride injection by HPLC, wherein the impurities include diclofenac sodium impurity A, diclofenac sodium impurity B, diclofenac sodium impurity C, diclofenac sodium impurity D, diclofenac sodium impurity E, diclofenac sodium impurity F, lidocaine hydrochloride impurity A, lidocaine hydrochloride impurity B, lidocaine hydrochloride impurity C, lidocaine hydrochloride impurity D, lidocaine hydrochloride impurity E, lidocaine hydrochloride impurity F, lidocaine hydrochloride impurity G, lidocaine hydrochloride impurity H, lidocaine hydrochloride impurity I, and lidocaine hydrochloride impurity J; The chromatographic conditions are: Chromatographic column: Thermo GOLD C18 4.6*250mm 5μm; Mobile phase: Mobile phase A is acetonitrile-phosphate buffer; mobile phase B is acetonitrile-water solution; Column temperature: 40°C; Flow rate: 1.2 ml / min; Detection wavelength: 230nm; Injection volume: 20 μl; Elution method: gradient elution, elution conditions are as follows: 。 2. The quality detection method of diclofenac sodium and lidocaine hydrochloride injection according to claim 1, characterized in that: The steps include: a. Preparation of test solution: Accurately measure 1 ml of diclofenac sodium and lidocaine hydrochloride injection, place in a 10 ml volumetric flask, and dilute to the mark with 10% acetonitrile; b. Preparation of impurity control: Weigh lidocaine hydrochloride impurities A / B / C / D / E / F / G / H / I / J, add acetonitrile to dissolve, and then add 10% acetonitrile to prepare an impurity reference substance mother solution; weigh diclofenac sodium impurities A / B / C / D / E / F, add acetonitrile to dissolve, and then add 10% acetonitrile to prepare an impurity reference substance mother solution; weigh lidocaine hydrochloride bulk drug and diclofenac sodium bulk drug into the same volumetric flask, add the impurity reference substance mother solution to prepare a mixed solution containing 0.1% of each impurity relative to lidocaine hydrochloride, wherein the concentration of lidocaine hydrochloride is 2.5 mg / ml, and a mixed solution containing 0.1% of each impurity relative to diclofenac sodium, wherein the concentration of diclofenac sodium is 7.5 mg / ml; c. Preparation of control solution: Accurately measure 1 ml of the test solution and dilute it to 100 ml with 10% acetonitrile; d. Detection according to the HPLC chromatographic conditions of claim 1.

3. The quality detection method of diclofenac sodium and lidocaine hydrochloride injection according to claim 1, characterized in that: The pH of the acetonitrile-phosphate buffer solution was adjusted to 8.0 with sodium hydroxide.

4. The quality detection method of diclofenac sodium and lidocaine hydrochloride injection according to any one of claims 1 to 3, characterized in that: The retention times of the detected impurities are: Diclofenac Impurity E: 8.778 min, Lidocaine Hydrochloride Impurity C: 10.057 min, Lidocaine Hydrochloride Impurity B: 10.832 min, Lidocaine Hydrochloride Impurity D: 15.329 min, Lidocaine Hydrochloride Impurity H: 18.3 min, Lidocaine Hydrochloride Impurity A: 20.557 min, Lidocaine Hydrochloride Impurity G: 22.094 min, Diclofenac Impurity D: 25.694 min, Lidocaine Hydrochloride Impurity E: 28.923 min, Diclofenac Impurity A: 41.13 min, Lidocaine Hydrochloride Impurity F: 43.995 min, Diclofenac Impurity C: 44.584 min, Lidocaine Hydrochloride Impurity I: 45.982 min, Lidocaine Hydrochloride Impurity J: 46.619 min. min, diclofenac impurity F: 49.393 min, diclofenac impurity B: 52.031 min, and the retention time fluctuated by 0.4 min.

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