Method for detecting lactic acid and lactic acid condensate in pentazocine injection

Abstract

The invention belongs to the technical field of analysis and detection, and particularly relates to a method for detecting lactic acid and a lactic acid condensate in a pentazocine injection. The method for detecting the lactic acid and the lactic acid condensate in the pentazocine injection comprises the following steps: preparing a system adaptive solution, a lactic acid reference substance solution, a lactic acid condensate reference substance solution, a pentazocine substrate solution and a test solution; and respectively injecting the blank solution, the system adaptive solution, the lactic acid reference substance solution, the lactic acid condensate reference substance solution, the pentazocine substrate solution and the test solution into a liquid chromatograph, carrying out liquid chromatography detection, recording a chromatogram, and obtaining the contents of lactic acid and lactic acid condensate in the test solution according to a peak area normalization method. The invention aims to overcome the defects in the prior art, provides the method for detecting the lactic acid and the lactic acid condensate in the pentazocine injection, and realizes the accurate determination of the lactic acid and the lactic acid condensate in the pentazocine injection by arranging a plurality of groups of control solutions.

Description

Technical Field

[0001] The invention belongs to the technical field of analysis and detection, and particularly relates to a method for detecting lactic acid and lactic acid condensates in pentazocine injection. Background Art

[0002] Lactic acid, also known as 2-hydroxypropionic acid and α-hydroxypropionic acid, has an asymmetric carbon atom in its molecular structure, forming two optical isomers, d-isomer, l-isomer and racemic isomer dl-isomer, a total of three optical isomers. It is an organic acid with the second largest production and consumption after citric acid. In recent years, due to the expanded application of L-lactic acid in the pharmaceutical industry and biodegradable plastics, its demand has been increasing.

[0003] Lactic acid is widely present in nature and is found in all living organisms. There are right-handed and racemic isomers in human and animal meat tissues, while the left-handed isomer is a normal metabolite of mammals; due to the presence of hydroxyl and carboxyl groups in the molecule, it has the functions of these two functional groups, forming carboxylic acid esters with acid anhydrides, lactic acid esters with alcohols, and salts with sodium, calcium, ferrous ions, etc.; in addition, lactic acid can undergo self-esterification to form linear polyesters, and even cyclic compounds, that is, cyclic dimer lactide.

[0004] Lactic acid can be used as an excipient in medicine. The Pharmacopoeia of the People's Republic of China (2020 edition) states that lactic acid is a mixture of 2-hydroxypropionic acid and its condensate, and its lactic acid content, calculated as C3H6O3, should be 85.0-92% (g / g). Therefore, medicinal lactic acid contains not only lactic acid monomers but also lactic acid condensates. Take 130 mg of lactic acid, put it in a syringe bottle, add 9 ml of water, mix well, inject the lactic acid solution into a liquid chromatograph, and use mass spectrometry to extract the molecular weight of the chromatographic peak, obtaining lactic acid with a molecular weight of 88.9, lactic acid dimer with a molecular weight of 161.2, and lactic acid trimer with a molecular weight of 233.3. The mass spectrum confirming the molecular weight of medicinal lactic acid is as follows Figure 1 shown.

[0005] Pentazocine, also known as Pentazocine and Analgesic, has a chemical formula of C19H27NO and a molecular weight of 285.43. It is an opioid receptor agonist / antagonist analgesic and is included in the second category of psychotropic drugs. Its most common dosage form is pentazocine injection. Pentazocine injection is suitable for analgesia of various surgical anesthesia and can be used for anesthesia induction, intraoperative anesthesia, postoperative analgesia, etc. In pentazocine injection, the active ingredient is pentazocine, and the auxiliary ingredients are lactic acid, sodium chloride and water for injection. The pH value of pentazocine injection should be in the range of 4.0-5.0. Medicinal lactic acid mainly plays a solubilizing role in the prescription of pentazocine injection (1ml:30mg). Specifically, lactic acid can help pentazocine to dissolve better in water, thereby improving the stability of the drug, which is very important for ensuring that the drug can be quickly absorbed and take effect after injection; in addition, lactic acid also has the function of improving bioavailability: by improving the solubility of pentazocine, it helps to improve the bioavailability of pentazocine and make its distribution in the body more even, thereby enhancing its analgesic effect. Medicinal lactic acid accounts for about 1.5% of the prescription of pentazocine injection. As the product is stored for a long time or irregularly, some condensation products (such as dimers and trimers) in the lactic acid product will depolymerize to generate lactic acid, resulting in an increase in the proportion of lactic acid in the prescription and a decrease in the pH value of pentazocine injection, which in turn causes the pH value of the product to decrease, resulting in non-compliance with regulations, affecting its clinical analgesic efficacy and reducing the clinical medicinal value of pentazocine injection. Therefore, in order to further ensure the efficacy of pentazocine injection, it is necessary to determine the content of lactic acid and lactic acid dimers in pentazocine injection; in addition, in actual use, the medicinal lactic acid will be pretreated to ensure the efficacy of pentazocine injection.

[0006] The process of pre-treating lactic acid and lactic acid condensates is as follows: adding a certain amount of aqueous solution and keeping it at 94°C-99°C for 12 hours to depolymerize the lactic acid condensates. After the preparation is completed, the lactic acid condensates will depolymerize again during terminal sterilization. After the process treatment, the lactic acid solutions before and after the treatment are analyzed, such as Figure 2-Figure 3 As shown, before treatment, the lactic acid peak area content was 62.49%, the lactic acid dimer peak area content was 29.70%, and the lactic acid trimer peak area content was 1.18%. After treatment, the lactic acid peak area content was 99.11%, and the lactic acid dimer peak area content was 0.89%. The lactic acid condensate in the sample has been depolymerized for many times, and it is difficult for lactic acid polymers to exist in the residual lactic acid condensate. The main lactic acid dimer (i.e., lactic acid ester) exists. Therefore, in order to further ensure the efficacy of pentazocine injection, it is necessary to determine the content of lactic acid and lactic acid dimer in pentazocine injection.

[0007] CN115097037A discloses a method for detecting lactic acid in pentazocine injection. The method comprises the following steps: mixing a sample to be tested with an inorganic strong acid to obtain a sample liquid to be tested; using liquid chromatography, the sample liquid to be tested is detected under the conditions that the mobile phase is a phosphoric acid aqueous solution-acetonitrile system, the flow rate of the mobile phase is 1 mL / min, the detection wavelength is 215 nm, and the elution mode is isocratic elution; the content of lactic acid in the sample to be tested is calculated by an external standard method in combination with a standard chromatogram; and the high-accuracy detection of lactic acid in pentazocine injection is achieved by limiting the liquid chromatography conditions; the method can only quantitatively determine the content of lactic acid in pentazocine injection, and cannot monitor the amount of lactic acid dimers in real time, so that when the lactic acid content is exceeded, the cause of the lactic acid exceeding the limit cannot be accurately found.

[0008] CN110988237A discloses a method for detecting components in a mixed solution, mainly targeting hydroxyl-containing organic acid monomers and polycondensates thereof, such as lactic acid and its polymers. The method uses reverse phase liquid chromatography, and the mobile phase is a mixture of an alkaline ion pair reagent (such as tetramethylammonium hydroxide), a polar solvent (water) and a medium polar solvent (acetonitrile). With the help of a gradient elution program, the proportion of acetonitrile is gradually increased within 0-24 minutes to allow components of different polarities to be separated in sequence; an ultraviolet detector is used, with a wavelength of 210nm, a column temperature of 40°C, a flow rate of 1.0ml / min, and a test sample concentration of 3mg / ml. This method can effectively separate lactic acid monomers, lactide and tetramers, etc., with symmetrical peak shapes and good separation, and is suitable for quality monitoring of pharmaceutical excipients; however, the method is mainly targeted at lactic acid mixed solutions, and the solvent is a mixture of (water) and a medium polar solvent (acetonitrile), which increases the discharge of organic boiling water; the mobile phase uses an alkaline ion pair reagent, which increases the loss of chromatographic consumables, shortens its service life, and increases the detection cost. Summary of the invention

[0009] The purpose of the present invention is to overcome the defects of the prior art and provide a method for detecting lactic acid and lactic acid condensates in pentazocine injection. By setting up multiple groups of control solutions, accurate determination of lactic acid and lactic acid condensates in pentazocine injection is achieved.

[0010] The method for detecting lactic acid and lactic acid condensates in pentazocine injection of the present invention comprises the following steps: preparing a system adaptability solution, a lactic acid reference solution, a lactic acid condensate reference solution, a pentazocine base solution and a test solution, respectively injecting a blank solution, a system adaptability solution, a lactic acid reference solution, a lactic acid condensate reference solution, a pentazocine base solution and a test solution into a liquid chromatograph, performing liquid chromatography detection, recording a chromatogram, and obtaining the content of lactic acid and lactic acid condensates in the test solution by a peak area normalization method.

[0011] The system adaptability solution is prepared by weighing a medicinal lactic acid sample and diluting it with water to prepare a system adaptability solution; the concentration of the medicinal lactic acid in the system adaptability solution is 14.0-15.0 mg / mL, and preferably, the concentration of the medicinal lactic acid in the system adaptability solution is 14.5 mg / mL.

[0012] The medicinal lactic acid sample is a mixture of 2-hydroxypropionic acid and its condensate, preferably medicinal lactic acid (L-2-hydroxypropionic acid) produced by Wuxi Fuqi Co., Ltd., with a purity of 88.8% (g / g).

[0013] The preparation method of the lactic acid reference solution is as follows: weigh a medicinal lactic acid sample, add 2.0-4.0 ml of 0.5-2.0 mol / L sodium hydroxide solution, place in a 94-99° C. water bath for 5-20 min, cool to room temperature, add 2.0-4.0 ml of 0.5-2.0 mol / L hydrochloric acid, dilute with water to prepare a lactic acid reference solution; the concentration of the medicinal lactic acid in the lactic acid reference solution is 14.0-15.0 mg / mL, and preferably, the concentration of the medicinal lactic acid in the lactic acid reference solution is 14.5 mg / mL.

[0014] The preparation method of the lactic acid condensate reference solution is as follows: weigh a lactic acid condensate sample, dilute it with water, and prepare a lactic acid condensate reference solution; the concentration of the lactic acid condensate in the lactic acid condensate reference solution is 0.3-0.4 mg / mL, preferably, the concentration of the lactic acid condensate in the lactic acid condensate reference solution is 0.36 mg / mL; wherein the lactic acid condensate sample is a lactic acid dimer with a purity of 98.5 wt.%, purchased from Guangzhou CATO Technology Co., Ltd. (CATO), and the structural formula is as follows:

[0015]

[0016] The blank solution is water for injection, and the test solution is pentazocine injection.

[0017] The preparation process of the pentazocine base solution is as follows: weigh 30 mg of pentazocine raw material and 2.8 mg of sodium chloride, dissolve in 1 ml of injection water and shake well to obtain the pentazocine base solution.

[0018] The liquid chromatography detection conditions are as follows: an octadecylsilane bonded silica gel column is used, the column temperature of the chromatographic column is 30°C; the detector is an ultraviolet detector, and the detection wavelength is 210nm; the mobile phase A is a 0.1% (v / v) phosphoric acid aqueous solution, and the mobile phase B is acetonitrile; the total flow rate of the mobile phase A and the mobile phase B is 1.0mL / min; the injection volume is 10-20μL; preferably, the chromatographic column is GL ODS-3 (4.6×250mm, 5μm).

[0019] The liquid chromatography detection conditions also include a gradient elution program, and the gradient elution program is as follows:

[0020] 0→5min: 100 parts of mobile phase A, 0 parts of mobile phase B;

[0021] 5→15min: Mobile phase A 100 parts→60 parts, mobile phase B 0 parts→40 parts;

[0022] 15.1→25min: Mobile phase A 60 parts→40 parts, mobile phase B 40 parts→60 parts;

[0023] 25.1→35min: 40 parts of mobile phase A, 60 parts of mobile phase B;

[0024] 35.1→36min: Mobile phase A 40 parts→100 parts, mobile phase B 60 parts→0 parts;

[0025] 36.1→45min: 100 parts of mobile phase A, 0 parts of mobile phase B.

[0026] Preferably, the method for detecting lactic acid and lactic acid condensates in pentazocine injection comprises the following steps:

[0027] (1) Preparation of system adaptability solution: Weigh 145 mg of medicinal lactic acid into a 10 ml volumetric bottle, dilute to the mark with water, and shake well;

[0028] (2) Lactic acid reference solution: Take 145 mg of medicinal lactic acid, accurately weigh it, put it in a 10 ml volumetric flask, add 3 ml of 1 mol / L sodium hydroxide solution, incubate it in a 100°C water bath for 10 min, let it cool to room temperature, add 3 ml of 1 mol / L hydrochloric acid, dilute it to the mark with water, shake well, and the solution is the lactic acid reference solution.

[0029] (3) Lactic acid dimer reference solution: Take 18 mg of lactic acid dimer, accurately weigh it, place it in a 50 ml volumetric flask, dilute it to the mark with water, and shake well;

[0030] (4) Test solution: Pentazocine injection solution;

[0031] (5) Blank solution: water for injection;

[0032] (6) Pentazocine base solution: accurately weigh 30 mg of pentazocine raw material and 2.8 mg of sodium chloride and dissolve in 1 ml of water for injection;

[0033] (7) The above solution was subjected to liquid chromatography detection; the liquid chromatography detection conditions were as follows: the chromatographic column was an octadecylsilane bonded silica column GL ODS-3 (4.6×250 mm, 5 μm), the mobile phase A was a 0.1% (v / v) phosphoric acid aqueous solution, and the mobile phase B was acetonitrile; the injection volume was 10 μL, the mobile phase flow rate was 1.0 mL / min, the detection wavelength was 210 nm, and the column temperature was 30° C.; the elution method was gradient elution.

[0034] The specific parameters of the gradient elution are: 0→5min: 100 parts of mobile phase A, 0 parts of mobile phase B;

[0035] 5→15min: Mobile phase A 100 parts→60 parts, mobile phase B 0 parts→40 parts;

[0036] 15.1→25min: Mobile phase A 60 parts→40 parts, mobile phase B 40 parts→60 parts;

[0037] 25.1→35min: 40 parts of mobile phase A, 60 parts of mobile phase B;

[0038] 35.1→36min: Mobile phase A 40 parts→100 parts, mobile phase B 60 parts→0 parts;

[0039] 36.1→45min: 100 parts of mobile phase A, 0 parts of mobile phase B.

[0040] The pentazocine injection used in the present invention is a product produced by Shandong Xinhua Pharmaceutical Co., Ltd., and its main components are: pentazocine, lactic acid, sodium chloride, and water for injection. The preparation process comprises the following steps: depolymerization of medicinal lactic acid, stirring at 94-99 DEG C for 12 hours, sampling and testing to meet the standards, cooling to below 60 DEG C, adding pentazocine and sodium chloride (for injection), stirring for 60-90 minutes to completely dissolve them, cooling to below 30 DEG C, controlling the pH range to 4.0-5.0, adding water for injection to the required preparation amount, stirring, and then filtering, potting, sterilizing, and packaging.

[0041] The system adaptability solution, lactic acid reference solution, lactic acid dimer solution, blank solution and pentazocine base solution of the present invention are subjected to chromatographic analysis to evaluate the separation degree of lactic acid peak and lactic acid dimer peak, and lactic acid and lactic acid ester in the system adaptability solution are sequentially peaked, and the separation degree between lactic acid and lactic acid dimer (lactylic acid ester) and adjacent peaks should be not less than 1.5, so that the peak positions of lactic acid and lactic acid dimer in pentazocine injection are not interfered by the peaks of blank solution, pentazocine raw material and other impurities, and lactic acid and lactic acid dimer can be quickly quantitatively analyzed, thereby ensuring that the measurement result is more scientific and accurate.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) The method for detecting lactic acid and lactic acid condensates in pentazocine injection of the present invention increases the preparation of system applicability solution, can fully and early evaluate the service life of the chromatographic column, reduce detection costs, reduce energy and consumption, and at the same time, the diluent is water, and the water phase accounts for a large proportion in the mobile phase gradient elution process, which reduces the proportion of the organic phase, thereby reducing the discharge of organic wastewater, saving energy and protecting the environment.

[0044] (2) The method for detecting lactic acid and lactic acid condensates in pentazocine injection of the present invention realizes accurate positioning of lactic acid and lactic acid dimers by setting multiple groups of control solutions, which is convenient for rapid detection and analysis, and ensures that the detection of target compounds in the test sample is not interfered by excipients, active ingredients and other impurities, so that the results are more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 Confirm the mass spectrum of the molecular weight of the chromatographic peak extracted from the medicinal lactic acid;

[0046] Figure 2 The HPLC chromatogram of the lactic acid solution before treatment is measured by the method provided by the present invention;

[0047] Figure 3 The method provided by the present invention measures the HPLC chromatogram after the lactic acid solution is treated;

[0048] Figure 4 HPLC chromatogram of system suitability solution measured for Example 1;

[0049] Figure 5 HPLC chromatogram of lactic acid reference substance solution obtained for Example 1;

[0050] Figure 6 The HPLC chromatogram of the lactic acid dimer reference substance solution obtained in Example 1;

[0051] Figure 7 It is the HPLC chromatogram of the test solution in Example 1;

[0052] Figure 8 It is a superimposed liquid chromatogram of the blank solution, the test sample, the lactic acid reference solution, and the lactic acid dimer reference solution in Example 1;

[0053] Fig. 9 This is the HPLC detection chromatogram of pentazocine base solution;

[0054] Fig.10 This is the HPLC chromatogram of pentazocine injection (batch number: 2207020) in Example 2;

[0055] Fig.11This is the HPLC chromatogram of the commercially available pentazocine injection test product (original manufacturer: Japan Maruishi Pharmaceutical Co., Ltd., batch number: 93141). DETAILED DESCRIPTION

[0056] The present invention is further described below in conjunction with the embodiments and drawings. The equipment used in the detection method of the present invention can all be known equipment in the art. The raw and auxiliary materials used in the present invention are commercially available unless otherwise specified, and some of the raw materials are described as follows:

[0057] Medicinal lactic acid (L-2-hydroxypropionic acid): Wuxi Fuqi Pharmaceutical Co., Ltd., batch number: CD230102CV, purity: 88.8% (g / g);

[0058] Lactic acid dimer (milky lactic acid): purity 98.5wt.%, purchased from Guangzhou CATO Technology Co., Ltd. (CATO);

[0059] Pentazocine: Shandong Xinhua Pharmaceutical Co., Ltd.;

[0060] Pentazocine injection: produced by Shandong Xinhua Pharmaceutical Co., Ltd.

[0061] Example 1

[0062] The method for detecting lactic acid and lactic acid condensates in pentazocine injection comprises the following steps:

[0063] (1) Preparation of system adaptability solution: Weigh 145 mg of medicinal lactic acid into a 10 ml volumetric flask, dilute to the mark with water, and shake well;

[0064] (2) Lactic acid reference solution: Take 145 mg of medicinal lactic acid, accurately weigh it, put it in a 10 ml volumetric flask, add 3 ml of 1 mol / L sodium hydroxide solution, incubate it in a 100°C water bath for 10 min, let it cool to room temperature, add 3 ml of 1 mol / L hydrochloric acid, dilute it to the mark with water, shake well, and the solution is the lactic acid reference solution.

[0065] (3) Lactic acid dimer reference solution: Take 18 mg of lactic acid dimer, accurately weigh it, place it in a 50 ml volumetric flask, dilute it to the mark with water, and shake well;

[0066] (4) Test solution: Pentazocine injection (batch number: 2207020);

[0067] (5) Blank solution: water for injection;

[0068] (6) Pentazocine base solution: accurately weigh 30 mg of pentazocine raw material and 2.8 mg of sodium chloride and dissolve in 1 ml of water for injection;

[0069] (7) Perform liquid chromatography on the above solution and record the chromatogram; the results are shown in Figure 4-Figure 9 ; The liquid chromatography detection conditions are as follows: the chromatographic column is an octadecylsilane bonded silica gel column GL ODS-3 (4.6×250mm, 5μm), the mobile phase A is a 0.1% (v / v) phosphoric acid aqueous solution, and the mobile phase B is acetonitrile; the injection volume is 10μL, the mobile phase flow rate is 1.0mL / min, the detection wavelength is 210nm, the column temperature is 30°C, and the elution method is gradient elution.

[0070] The specific parameters of the gradient elution are: 0→5min: 100 parts of mobile phase A, 0 parts of mobile phase B;

[0071] 5→15min: Mobile phase A 100 parts→60 parts, mobile phase B 0 parts→40 parts;

[0072] 15.1→25min: Mobile phase A 60 parts→40 parts, mobile phase B 40 parts→60 parts;

[0073] 25.1→35min: 40 parts of mobile phase A, 60 parts of mobile phase B;

[0074] 35.1→36min: Mobile phase A 40 parts→100 parts, mobile phase B 60 parts→0 parts;

[0075] 36.1→45min: 100 parts of mobile phase A, 0 parts of mobile phase B.

[0076] Figure 4 is the system suitability solution HPLC chromatogram, Figure 4 It can be seen that lactic acid, lactic acid dimer and lactic acid trimer peak in sequence. The peak area data are shown in Table 1.

[0077] Table 1 Data of components in system suitability solution

[0078]

[0079] Figure 5 is the HPLC chromatogram of lactic acid reference solution, Figure 5 It can be seen that lactic acid and lactic acid dimer peak in sequence, and the peak area data are shown in Table 2.

[0080] Table 2 Data of components in lactic acid reference solution

[0081]

[0082] Figure 6 The HPLC chromatogram of the lactic acid dimer reference substance solution was obtained for Example 1. Lactic acid and lactic acid dimer peaked in sequence. The peak area data are shown in Table 3.

[0083] Table 3 Data of components in lactic acid dimer reference solution

[0084]

[0085] Figure 7 This is the HPLC chromatogram of the test solution. Lactic acid, lactic acid dimer and pentazocine appear in sequence. The peak area data are shown in Table 4.

[0086] Table 4 Data of components in the test solution

[0087]

[0088] Figure 8 It is the superimposed liquid chromatogram of blank solution, test solution, lactic acid reference substance, and lactic acid dimer reference substance. From bottom to top, it is the HPLC chromatogram of blank solution, the HPLC chromatogram of test solution, the HPLC chromatogram of lactic acid reference substance solution, and the HPLC chromatogram of lactic acid dimer reference substance solution. Fig. 9 is the HPLC chromatogram of pentazocine base solution, Figure 8 , Fig. 9 The retention time and separation degree of each component are shown in Table 5.

[0089] Table 5 Retention time and separation of each component

[0090]

[0091] As can be seen from Table 5, the blank solvent and the pentazocine base solution did not interfere with the detection of lactic acid and lactic acid dimer. The minimum separation degree between lactic acid and lactic acid dimer and adjacent peaks in the test solution was 2.49, which was greater than 1.5, indicating that the chromatographic conditions of the present invention have good specificity.

[0092] Example 2

[0093] According to the detection method of lactic acid and lactic acid condensate in pentazocine injection described in Example 1, repeatability was verified.

[0094] Test sample: Take pentazocine injection batch 2207020 test sample, take 6 portions for determination in parallel, take 6 portions of the test sample solution and inject them into the liquid chromatograph, record the chromatographic peak content and calculate it by area normalization method. The repeatability test results are shown in Table 6, where the chromatogram of the test sample solution No. 1 is shown in Fig.10 ; The liquid chromatography detection conditions are as follows: the chromatographic column is an octadecylsilane bonded silica gel column GL ODS-3 (4.6×250mm, 5μm), the mobile phase A is a 0.1% (v / v) phosphoric acid aqueous solution, and the mobile phase B is acetonitrile; the injection volume is 10μL, the mobile phase flow rate is 1.0mL / min, the detection wavelength is 210nm, the column temperature is 30°C, and the elution method is gradient elution.

[0095] The specific parameters of the gradient elution are: 0→5min: 100 parts of mobile phase A, 0 parts of mobile phase B;

[0096] 5→15min: Mobile phase A 100 parts→60 parts, mobile phase B 0 parts→40 parts;

[0097] 15.1→25min: Mobile phase A 60 parts→40 parts, mobile phase B 40 parts→60 parts;

[0098] 25.1→35min: 40 parts of mobile phase A, 60 parts of mobile phase B;

[0099] 35.1→36min: Mobile phase A 40 parts→100 parts, mobile phase B 60 parts→0 parts;

[0100] 36.1→45min: 100 parts of mobile phase A, 0 parts of mobile phase B.

[0101] Table 6 Repeatability test results

[0102] serial number Lactic acid peak area (%) Lactic acid dimer peak area (%) 1 6.68 0.07 2 6.67 0.08 3 6.63 0.08 4 6.66 0.08 5 6.66 0.08 6 6.63 0.08 average 6.66 0.08 RSD(%) 0.31 5.1

[0103] As can be seen from the above table, the same sample was measured multiple times in parallel, which overcomes the defects of large result deviation and poor reproducibility, and ensures that the detection results of lactic acid and lactic acid dimer (milky lactic acid) content in the injection are stable and reliable.

[0104] Example 3

[0105] According to the detection method of lactic acid and lactic acid condensate in pentazocine injection described in Example 1, the repeatability of commercially available pentazocine injection was verified.

[0106] Test samples: Three batches of commercial-scale pentazocine injection samples (batch numbers: 24005100, 24005107, and 24005115) produced continuously by Shandong Xinhua Pharmaceutical Co., Ltd., one batch of pentazocine injection sold by Anhui Hengxing Pharmaceutical Co., Ltd. (batch number: 231231), and one batch of pentazocine injection sold by the original manufacturer, Japan Maruishi Pharmaceutical Co., Ltd. (batch number: 93141) were used as test samples for testing. They were injected into the liquid chromatograph respectively, and the chromatographic peak content was recorded and calculated by the area normalization method. The test results are shown in Table 7, among which the chromatogram of the pentazocine injection sold by the original manufacturer, Japan Maruishi Pharmaceutical Co., Ltd., is shown in Table 7. Fig.11 ; The liquid chromatography detection conditions are as follows: the chromatographic column is an octadecylsilane bonded silica gel column GLODS-3 (4.6×250mm, 5μm), the mobile phase A is a 0.1% (v / v) phosphoric acid aqueous solution, and the mobile phase B is acetonitrile; the injection volume is 10μL, the mobile phase flow rate is 1.0mL / min, the detection wavelength is 210nm, the column temperature is 30°C, and the elution method is gradient elution.

[0107] The specific parameters of the gradient elution are: 0→5min: 100 parts of mobile phase A, 0 parts of mobile phase B;

[0108] 5→15min: Mobile phase A 100 parts→60 parts, mobile phase B 0 parts→40 parts;

[0109] 15.1→25min: Mobile phase A 60 parts→40 parts, mobile phase B 40 parts→60 parts;

[0110] 25.1→35min: 40 parts of mobile phase A, 60 parts of mobile phase B;

[0111] 35.1→36min: Mobile phase A 40 parts→100 parts, mobile phase B 60 parts→0 parts;

[0112] 36.1→45min: 100 parts of mobile phase A, 0 parts of mobile phase B.

[0113] Table 7 Repeatability verification results of commercially available pentazocine injection

[0114]

[0115] Comparison of three batches of pentazocine injection produced continuously by Shandong Xinhua Pharmaceutical Co., Ltd., pentazocine injection samples produced by the original manufacturer and Anhui Hengxing Pharmaceutical Co., Ltd. showed that the lactic acid content was basically the same, and there was no significant difference in the lactic acid dimer content, which was at the same content level. Therefore, the method of the present invention realizes the detection of lactic acid and lactic acid condensate content in pentazocine injection.

Claims

1. A method for detecting lactic acid and lactic acid condensates in pentazocine injection, characterized in that: The following steps are involved: Prepare system suitability solution, lactic acid reference solution, lactic acid condensate reference solution, pentazocine base solution and test solution, inject blank solution, system suitability solution, lactic acid reference solution, lactic acid condensate reference solution, pentazocine base solution and test solution into liquid chromatograph, perform liquid chromatography detection, record the chromatogram, and obtain the content of lactic acid and lactic acid condensate in the test solution by peak area normalization method.

2. The method for detecting lactic acid and lactic acid condensates in pentazocine injection according to claim 1, characterized in that: The preparation method of the system adaptability solution is: weigh a medicinal lactic acid sample, dilute it with water, and prepare the system adaptability solution; the concentration of the medicinal lactic acid in the system adaptability solution is 14.0-15.0 mg / mL.

3. The method for detecting lactic acid and lactic acid condensates in pentazocine injection according to claim 2, characterized in that: The medicinal lactic acid sample was taken as a mixture of 2-hydroxypropionic acid and its condensate.

4. The method for detecting lactic acid and lactic acid condensates in pentazocine injection according to claim 1, characterized in that: The preparation method of the lactic acid reference solution is as follows: weigh a medicinal lactic acid sample, add 2.0-4.0 ml of 0.5-2.0 mol / L sodium hydroxide solution, place in a 94-99°C water bath for 5-20 min, cool to room temperature, add 2.0-4.0 ml of 0.5-2.0 mol / L hydrochloric acid, dilute with water to prepare a lactic acid reference solution; the concentration of medicinal lactic acid in the lactic acid reference solution is 14.0-15.0 mg / mL.

5. The method for detecting lactic acid and lactic acid condensates in pentazocine injection according to claim 1, characterized in that: The preparation method of the lactic acid condensate reference solution is as follows: weigh the lactic acid condensate sample, dilute it with water, and prepare the lactic acid condensate reference solution; the concentration of the lactic acid condensate in the lactic acid condensate reference solution is 0.3-0.4 mg / mL.

6. The method for detecting lactic acid and lactic acid condensates in pentazocine injection according to claim 1, characterized in that: The lactic acid condensate sample is a lactic acid dimer with a purity of 98.5 wt.%.

7. The method for detecting lactic acid and lactic acid condensates in pentazocine injection according to claim 1, characterized in that: The blank solution was water for injection, and the test solution was pentazocine injection.

8. The method for detecting lactic acid and lactic acid condensates in pentazocine injection according to claim 1, characterized in that: The preparation process of the pentazocine base solution is as follows: weigh 30 mg of the pentazocine raw material, 2.8 mg of sodium chloride, dissolve in 1 ml of injection water and shake well to obtain the pentazocine base solution.

9. The method for detecting lactic acid and lactic acid condensates in pentazocine injection according to claim 1, characterized in that: The liquid chromatography detection conditions are as follows: an octadecylsilane bonded silica gel column is used, the column temperature of the chromatographic column is 30°C; the detector is an ultraviolet detector, and the detection wavelength is 210nm; the mobile phase A is a 0.1% phosphoric acid aqueous solution by volume concentration, and the mobile phase B is acetonitrile; the total flow rate of the mobile phase A and the mobile phase B is 1.0mL / min; and the injection volume is 10-20μL.

10. The method for detecting lactic acid and lactic acid condensates in pentazocine injection according to claim 1, characterized in that: The liquid chromatography detection conditions also include a gradient elution program, which is as follows: 0→5min: 100 parts of mobile phase A, 0 parts of mobile phase B; 5→15min: Mobile phase A 100 parts→60 parts, mobile phase B 0 parts→40 parts; 15.1→25min: Mobile phase A 60 parts→40 parts, mobile phase B 40 parts→60 parts; 25.1→35min: 40 parts of mobile phase A, 60 parts of mobile phase B; 35.1→36min: Mobile phase A 40 parts→100 parts, mobile phase B 60 parts→0 parts; 36.1→45min: 100 parts of mobile phase A, 0 parts of mobile phase B.

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