Method for detecting and evaluating leached substances PVP (Polyvinyl Pyrrolidone) and DMAC (Dimethylacetamide) in hollow fiber membrane separator

Abstract

The invention provides a method for detecting and evaluating leached substances PVP (polyvinyl pyrrolidone) and DMAC (dimethylacetamide) in a hollow fiber membrane separator, which comprises the following steps: extracting the hollow fiber membrane separator with pure water to obtain a to-be-detected solution; pVP and DMAC are taken respectively and dissolved with pure water, and a reference solution is obtained; detecting the to-be-detected liquid by adopting high performance liquid chromatography to obtain a chromatogram of the to-be-detected liquid; determining the reference substance solution by adopting a high performance liquid chromatography to obtain a chromatogram of the reference substance; performing qualitative and quantitative analysis on the chromatogram components of the to-be-detected liquid according to the chromatogram of the reference substance; the chromatographic conditions of the high performance liquid chromatography are as follows: the volume ratio of a mobile phase to a methanol-water mixed solution is (1-20): (80-99). According to the method, the methanol / water mixed solution is used as a mobile phase, dual detection of the leached substances PVP and DMAC in the hollow fiber membrane separator is realized through a proper mixing ratio, the chromatographic peak separation degree is greater than 1.5, and the test requirement is met.

Description

Technical Field

[0001] This invention relates to the field of blood purification, and in particular to a method for detecting and evaluating the leachable material PVP and DMAC in a hollow fiber membrane separator. Background Technology

[0002] Blood purification is an important treatment method used to remove harmful substances or excess water from the body to maintain metabolic balance. Due to advancements in modern medicine and improved living standards, the incidence of various kidney diseases and poisoning disorders is increasing year by year, leading to a growing demand for blood purification and underscoring its importance. Membrane separation technology is a novel blood purification technology developed in recent years, boasting high filtration efficiency and good biocompatibility. By selecting membrane materials with different pore sizes, it achieves the screening and separation of molecules of varying sizes in the blood. For example, in uremia patients, small molecules such as creatinine and urea in the blood can be effectively removed through the hollow fiber membrane of a hollow fiber membrane separator, while retaining large molecular nutrients such as proteins. For other blood purification treatments, plasma separators can be used to separate blood cells and plasma components, thereby removing harmful substances such as pathological antibodies and inflammatory factors from the patient's plasma and alleviating their condition.

[0003] Currently, hollow fiber membranes made from second-generation polymers such as polysulfone (PSF) and polyethersulfone (PES) exhibit excellent thermal, chemical, and mechanical stability. Polyethersulfone, with its high mechanical strength, stable chemical composition, and good resistance to pressure, heat, aging, and corrosion, can undergo multiple steam sterilizations, is easily reusable, and has a long service life, thus dominating the market for medical device membranes. Polysulfone-type hollow fiber membranes are prepared using polysulfone as the film-forming polymer, polyvinylpyrrolidone (PVP) as the pore-forming agent, and N,N-dimethylacetamide (DMAC) as the solvent, employing an immersion precipitation phase inversion method.

[0004] The addition of water-soluble PVP has two advantages: firstly, it facilitates phase separation during the pore formation of membrane fibers, ensuring that the prepared fiber membrane fibers have ideal pore sizes; secondly, PVP effectively improves the hydrophilicity of the fiber membrane fibers, thereby improving the blood compatibility of the membrane material. Although PVP is physiologically inert, does not irritate the skin or eyes, and does not cause skin allergies, its dissolution limit in Class III medical device dialyzers should be monitored. DMAC, as an important industrial solvent, is used in the synthesis of hollow fiber membranes. It generally enters the body through the respiratory tract or skin, causing damage to multiple organs, including the nervous system, liver, kidneys, and heart.

[0005] Due to the characteristics of the manufacturing process, PVP and DMAC inevitably remain in the fiber membrane during production and directly enter the bloodstream during blood purification treatment, causing harm to the human body. Therefore, it is necessary to measure and monitor the dissolution of these two substances. Furthermore, PVP raw materials have different K values. Currently, the commonly used PVP in dialyzers has K values ​​of 30 and 90. A K value of 30 indicates a relatively small molecular weight, making PVP easier to dissolve and significantly affecting hydrophilicity. PVP with a K value of 90 has a higher viscosity, making it less prone to precipitation, but affecting the pore size of the fiber membrane. Hydrophilic modification with PVP of K value 85 was considered. However, due to the coexistence of PVP 85 and DMAC, commonly used liquid chromatography cannot effectively separate their peak times, leading to inaccurate test results. Summary of the Invention

[0006] In view of this, the present invention provides a method for detecting and evaluating residual leachable material PVP and DMAC in hollow fiber membrane separators. The detection method provided by the present invention has good separation and accurate results.

[0007] This invention provides a method for detecting and evaluating residual leachable material (PVP) and dimethyl methacrylate (DMAC) in hollow fiber membrane separators, comprising:

[0008] A) The hollow fiber membrane separator was extracted with pure water to obtain the test solution;

[0009] PVP and DMAC were dissolved in pure water to obtain reference solutions.

[0010] B) The test solution is detected by high performance liquid chromatography (HPLC) to obtain a chromatogram of the test solution; the reference solution is determined by HPLC to obtain a chromatogram of the reference; and the components of the chromatogram of the test solution are qualitatively and quantitatively analyzed based on the chromatogram of the reference.

[0011] The chromatographic conditions for the high-performance liquid chromatography method are as follows:

[0012] The volume ratio of the mobile phase to the methanol-water mixture is (1~20):(80~99).

[0013] The problem this invention aims to solve is that, due to the coexistence of PVP85 and DMAC, commonly used liquid chromatography detection cannot effectively separate their elution times, resulting in inaccurate test results.

[0014] The method for detecting residual leachable material PVP and DMAC in hollow fiber membrane separators provided by the present invention first involves extracting the hollow fiber membrane separator with pure water to obtain the test solution.

[0015] In this invention, it is preferable to pre-rinse with physiological saline before using pure water extraction.

[0016] In a preferred embodiment of the present invention, the test solution is prepared by the following method:

[0017] The circulation tubing used in the experiment was rinsed with pure water. The hollow fiber membrane separator sample was connected to the circulation tubing. Physiological saline was used to thoroughly rinse the hollow fiber membrane passage inside the hollow fiber membrane separator at a flow rate of 100-400 mL / min. During this process, a rubber hammer was used to tap and remove air bubbles from the passage. The specific flow rate could be 100 mL / min, 200 mL / min, 300 mL / min, or 400 mL / min.

[0018] After the physiological saline has circulated completely, the physiological saline in the hollow fiber membrane separator is fully drained. Then, purified water is used as the extraction medium, and the mixture is extracted by circulating it for 4-6 hours at the test flow rate using a peristaltic pump to obtain the test solution. The test flow rate is 200 mL / min or 400 mL / min. The extraction time is preferably 6 hours.

[0019] In one specific embodiment of the present invention, 3L of purified water is used to rinse the circulation pipeline used for the experiment. The hollow fiber membrane separator sample is connected to the circulation pipeline. 500mL of physiological saline is used to thoroughly rinse the hollow fiber membrane passage inside the hollow fiber membrane separator at a flow rate of 100-400mL / min. During this process, a rubber hammer is used to tap and remove air bubbles from the passage.

[0020] After the physiological saline circulation is complete, the physiological saline in the hollow fiber membrane separator is fully drained. Then, 500 mL of purified water is taken as the extraction medium and the solution is fully circulated for 6 hours at the test flow rate using a peristaltic pump to extract the required extract for testing.

[0021] PVP and DMAC were dissolved in pure water to obtain reference solutions.

[0022] Before injecting the sample solution to be tested into a high-performance liquid chromatograph with pre-set chromatographic parameters, the present invention further includes:

[0023] According to the safety evaluation standard for leachable materials, the limit concentration A of PVP was determined, a PVP standard solution with a concentration of A was prepared, and injected into a high-performance liquid chromatograph with pre-set chromatographic parameters for liquid chromatography detection to obtain the test results of the PVP standard solution.

[0024] A set of DMAC standard solutions of known concentrations were injected into a high-performance liquid chromatograph with pre-set chromatographic parameters and detected by liquid chromatography to obtain the detection results of the set of DMAC standard solutions.

[0025] A standard curve for DMAC was established based on the concentrations of a set of DMAC standard solutions and the detection results.

[0026] The injection concentration of DMAC is 1~40 μg / mL. The linear regression equation is: y = 233452x - 17905, and the correlation coefficient r is... 2 = 0.9999.

[0027] Specifically, the separation degree of the PVP is greater than 1.5; the separation degree of the DMAC is greater than 1.5.

[0028] The K value of the PVP described in this invention is 85; the limit of quantitation of DMAC is 0.025 ug / mL.

[0029] The test solution was analyzed by high performance liquid chromatography (HPLC) to obtain a chromatogram; the reference solution was analyzed by HPLC to obtain a chromatogram; and the components of the test solution were qualitatively and quantitatively analyzed based on the chromatogram of the reference solution.

[0030] Preferably, the determination can be performed using the area percentage method. The peak time and peak area of ​​the test solution are compared with the test results of the standard solution to obtain the determination results of leachable PVP and DMAC, respectively.

[0031] The chromatographic column of this invention is a C18 column; the column specifications are 250 mm × 4.6 mm, 5 μm, and the column temperature is 20~30℃.

[0032] The detection wavelength described in this invention is 190nm~230nm. Specifically, it can be 190nm, 195nm, 200nm, 205nm, 210nm, 215nm, 220nm, 225nm, or 230nm.

[0033] The flow rate of the mobile phase described in this invention is 0.5~2.0 mL / min, specifically 0.5 mL / min, 1.0 mL / min, 1.5 mL / min, or 2.0 mL / min.

[0034] The injection volume described in this invention is 10~40μL; specifically, it can be 10μL, 15μL, 20μL, 25μL, 30μL, 35μL, or 40μL.

[0035] The mobile phase of this invention has a volume ratio of methanol-water mixed solution of (1~20):(80~99); specifically, it can be 1:99, 2:98, 3:97, 4:96, 5:95, 6:94, 7:93, 8:92, 9:91, 10:90, 11:89, 12:88, 13:87, 14:86, 15:85, 16:84, 17:83, 18:82, 19:81, or 20:80.

[0036] In a preferred embodiment of the present invention, the chromatographic conditions are as follows:

[0037] Detection wavelength: 205nm;

[0038] Mobile phase: Methanol:Water (volume ratio = 5:95)

[0039] Mobile phase flow rate: 0.5 mL / min

[0040] Injection volume: 20 μL

[0041] Detection time: 40 minutes;

[0042] Under the above conditions, the separation effect of this invention is optimal.

[0043] In a preferred embodiment of the present invention, the chromatographic conditions are as follows:

[0044] Detection wavelength: 190nm;

[0045] Mobile phase: Methanol:Water (volume ratio = 1:99)

[0046] Mobile phase flow rate: 1 mL / min;

[0047] The injection volume was 10 μL.

[0048] The detection time is 20 minutes;

[0049] In a preferred embodiment of the present invention, the chromatographic conditions are as follows:

[0050] Detection wavelength: 230nm;

[0051] Mobile phase: methanol:water (volume ratio = 20:80)

[0052] Mobile phase flow rate: 1 mL / min

[0053] Injection volume: 40 μL

[0054] The detection time is 60 minutes.

[0055] This invention provides a method for detecting and evaluating residual leachable polymers (PVP) and dimethyl methacrylate (DMAC) in hollow fiber membrane separators, comprising: A) extracting the hollow fiber membrane separator with pure water to obtain a test solution; dissolving PVP and DMAC separately in pure water to obtain a reference solution; B) detecting the test solution using high-performance liquid chromatography (HPLC) to obtain a chromatogram of the test solution; determining the reference solution using HPLC to obtain a chromatogram of the reference solution; and performing qualitative and quantitative analysis of the chromatogram components of the test solution based on the chromatogram of the reference solution; the HPLC conditions are as follows: the volume ratio of mobile phase to methanol-water mixture is (1~20):(80~99). This invention uses a methanol / water mixture as the mobile phase, and by using an appropriate mixing ratio, it can achieve dual detection of leachable polymers (PVP) and DMAC in hemodialysis machines, with a peak resolution greater than 1.5, meeting the accuracy requirements of the test. PVP can provide a qualitative result of whether safety is met by comparing the peak area with the safety limit requirements; DMAC can provide a linear standard curve to obtain quantitative test results. Attached Figure Description

[0056] Figure 1 Diagram of the testing setup;

[0057] Figure 2 This is the standard curve for PVP.

[0058] Figure 3 This is the standard curve for DMAC;

[0059] Figure 4 The chromatogram of the sample detection solution in Example 1 is shown below.

[0060] Figure 5 The chromatogram of the PVP spiked solution for the sample detection solution in Example 1 is shown below.

[0061] Figure 6 The chromatogram of the DMAC spiked solution in the sample test solution;

[0062] Figure 7 The test spectrum is for Comparative Example 1;

[0063] Figure 8 The test spectrum is for Comparative Example 2;

[0064] Figure 9 The test spectrum is for Comparative Example 3. Detailed Implementation

[0065] This invention provides a method for detecting and evaluating residual leachable material (PVP) and dimethyl methacrylate (DMAC) in hollow fiber membrane separators. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and fall within the scope of this invention. The method and application of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the method and application described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0066] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0067] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0068] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0069] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items.

[0070] DMAC: N,N-dimethylacetamide;

[0071] PVP: Polyvinylpyrrolidone.

[0072] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0073] The use of any and all instances or exemplary language such as “e.g.” or “including” in this document is merely intended to better illustrate the invention and is not intended to limit the scope of the invention unless the claims are made. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of the invention.

[0074] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0075] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0076] The embodiments and comparative examples of this invention describe some examples, in which the embodiments illustrate certain implementations of the invention. However, this does not mean that the effects of the invention can only be achieved in these examples.

[0077] To further illustrate the present invention, the following describes in detail, with reference to embodiments, a method for detecting and evaluating residual leachable material PVP and DMAC in a hollow fiber membrane separator provided by the present invention.

[0078] I. Materials and Reagents

[0079] Materials: Hemodialysis machine (Guangzhou Kang Sheng Biotechnology Co., Ltd.)

[0080] Reagents: Polyvinylpyrrolidone standard, sodium chloride injection, purified water, DMAC standard,

[0081] High performance liquid chromatograph (Shimadzu, Japan), ZORBAX Eclipse plus C18 column (Agilent).

[0082] II. Detection Methods and Procedures

[0083] (1) Solution preparation:

[0084] a. Preparation of polyvinylpyrrolidone (PVP) series standard solutions

[0085] Accurately weigh 100 mg of PVP standard into a 100 mL brown volumetric flask, dilute with water and bring to volume to obtain a standard stock solution with a concentration of 1.000 mg / mL. Take another 39 mL of the standard stock solution into a 100 mL brown volumetric flask, dilute with water and bring to volume to obtain a PVP standard solution with a concentration of 400 μg / mL. Prepare standard solutions with concentrations of 25, 50, 75, 100, 125, 150, 200, 300 and 400 μg / mL by stepwise dilution.

[0086] b. Preparation of N,N-dimethylacetamide (DMAC) series standard solutions

[0087] Accurately weigh 200 mg of DMAC standard into a 100 mL brown volumetric flask, dilute with water and bring to volume to obtain a standard stock solution with a concentration of 2.000 mg / mL. Take another 2 mL of the standard stock solution into a 100 mL brown volumetric flask, dilute with water and bring to volume to obtain a standard solution with a concentration of 40 μg / mL. Prepare standard solutions with concentrations of 1, 2.5, 5, 10, 15, 20, 25, 30, 35 and 40 μg / mL by stepwise dilution.

[0088] c. Preparation of leachable material detection solution

[0089] After connecting the tubing to both ends of the hemodialyzer according to the instructions of the multi-head peristaltic pump, pre-flush the blood chamber with 500 mL of normal saline. After pre-flushing, seal the dialysate end of the hemodialyzer, use purified water as the extraction medium, connect the blood end and the blue-capped bottle containing 500 mL of purified water to form a circulation system, place it in a constant temperature water bath at 37±1℃, and circulate and flush the hemodialyzer for 6 hours at flow rates of 200 mL / min and 400 mL / min respectively. Collect all circulating fluid as the test solution.

[0090] Figure 1 This is a diagram of the testing setup.

[0091] Example 1:

[0092] Column conditions:

[0093] The chromatographic column was a C18 column (250 mm × 4.6 mm, 5 μm).

[0094] Detection wavelength: 205nm;

[0095] Mobile phase: methanol:water (volume ratio = 5:95);

[0096] Mobile phase flow rate: 0.5 mL / min;

[0097] Injection volume: 20 μL;

[0098] Detection time: 40 minutes;

[0099] Methodological validation:

[0100] (1) Linearity verification of standard working solution

[0101] Linearity determination of PVP standard working solution:

[0102] Table 1

[0103]

[0104] Figure 2 The standard curve for PVP; linear regression equation: y = 119.89x + 397.93, correlation coefficient r 2 =0.9709.

[0105] Linearity determination of DMAC standard working solution:

[0106] Table 2

[0107]

[0108] Figure 3 The standard curve for DMAC; linear regression equation: y = 233452x - 17905, correlation coefficient r. 2 =0.9999.

[0109] As can be seen, when using a methanol / water mixed solution as the mobile phase for liquid chromatography detection, a linear standard curve can be plotted for DMAC standard solution. The DMAC content corresponding to different peak areas can be obtained through the standard curve. However, a linear standard curve cannot be obtained for PVP, and the accurate content of PVP cannot be quantitatively obtained.

[0110] According to the "SR-KC2102-2024091201 Safety Evaluation Study Report on Leachable Materials of High-Fluidity Hemodialysis Machines", the safety limit of PVP is confirmed to be 29 mg / vial, which means the concentration of the test solution is 58 ug / mL; the concentration of the comparative PVP standard solution is 50 ug / mL, and the peak area is measured under the same chromatographic conditions.

[0111] (2) Specificity verification

[0112] The sample test solution was analyzed, and the PVP and DMAC peaks were accurately detected. For leaching analysis, a PVP peak appeared at 15.752 min under the test conditions, and its area increased after the addition of PVP standard solution (250 μg / mL), confirming it as a PVP peak. The peak at 23.242 min was confirmed as a DMAC peak; the corresponding peak area increased after the addition of DMAC standard solution, confirming it as a DMAC peak. The peak localization was accurate, and the method showed good specificity.

[0113] The PVP peak resolution was 2.664, and the DMAC peak resolution was 6.905, both meeting the requirement of greater than 1.5, and can be considered as complete separation of the peak.

[0114] Figure 4 Chromatogram of the sample test solution; Figure 5 Chromatogram of the PVP spiked solution in the sample test solution; Figure 6 Chromatogram of DMAC spiked solution in sample test solution.

[0115] (3) Precision test

[0116] ①PVP Precision

[0117] A 400 μg / mL PVP standard solution was injected six times consecutively under chromatographic conditions, and the peak area was measured. The relative standard deviation of the six parallel determinations of the standard solution was less than 4%, indicating that the precision of this method for standard determination was good.

[0118] Table 3

[0119]

[0120] ②DMAC precision

[0121] A 40 μg / mL DMAC standard solution was injected six times consecutively under chromatographic conditions, and the peak area was measured. The relative standard deviation of the six parallel determinations of the standard solution was less than 4%, indicating that the precision of this method for standard determination was good.

[0122] Table 4

[0123]

[0124] (4) Recovery rate experiment

[0125] PVP recovery test: Using the sample as the matrix, the recovery and precision of PVP were determined at three spiking levels (low, medium, and high). Each spiking level was measured in triplicate. The method recovery and relative standard deviation (RSD) are shown in the table. The results showed that the average recovery of polyvinylpyrrolidone (PVP) was 96.99%–101.42%, and the relative standard deviation was 1.01%–8.40%, indicating that the accuracy of the method met the analytical requirements.

[0126] Table 5

[0127]

[0128] DMAC recovery test: Using the sample as the matrix, the recovery and precision of PVP were determined at three spiking levels (low, medium, and high). Each spiking level was measured in triplicate. The method recovery and relative standard deviation (RSD) are shown in the table. The results showed that the average recovery of polyvinylpyrrolidone (PVP) was 96.82%–98.57%, and the relative standard deviation was 0.08%–4.82%, indicating that the accuracy of the method met the analytical requirements.

[0129] Table 6

[0130]

[0131] (5) Validation of the limit of quantitation

[0132] The limit of detection (LOD) and limit of quantitation (LOQ) were determined using the signal-to-noise ratio (S / N) method. The DMAC standard stock solution was serially diluted with extraction medium, and the injection concentration at which the S / N ratio was approximately 10:1 was used as the LOD. The LOD for DMAC was determined to be 0.025 mg / L.

[0133] Table 7

[0134]

[0135] Example 2:

[0136] Column conditions:

[0137] The chromatographic column was a C18 column (250 mm × 4.6 mm, 5 μm).

[0138] Detection wavelength: 190nm;

[0139] Mobile phase: methanol:water (volume ratio = 1:99);

[0140] Mobile phase flow rate: 1 mL / min;

[0141] The injection volume was 10 μL;

[0142] The detection time is 20 minutes;

[0143] The results showed that this method also exhibited good specificity, high accuracy, and good precision. The peak resolution of the two methods was greater than 1.5. Under the test conditions, the sample detection solution showed a PVP peak at 15.739 min with a peak resolution of 2.699, and a DMAC peak at 24.194 min with a peak resolution of 1.668. The relative standard deviation (RSD) of the precision of the PVP method was 1.52%-5.17%, and the average recovery rate for low, medium, and high concentrations was 92.11%-95.12%. The RSD of the precision of the DMAC method was 0.13%-3.72%, and the average recovery rate for low, medium, and high concentrations was 96.33%-100.29%.

[0144] Example 3:

[0145] Column conditions:

[0146] The chromatographic column was a C18 column (250 mm × 4.6 mm, 5 μm).

[0147] Detection wavelength: 230nm;

[0148] Mobile phase: methanol:water (volume ratio = 20:80);

[0149] Mobile phase flow rate: 1 mL / min;

[0150] Injection volume: 40 μL;

[0151] The detection time is 60 minutes;

[0152] The results showed that this method also exhibited good specificity, high accuracy, and good precision. The peak resolution of the two methods was greater than 1.5. Under the test conditions, the sample detection solution showed a PVP peak at 15.767 min with a peak resolution of 4.137, and a DMAC peak at 24.205 min with a peak resolution of 2.481. The relative standard deviation (RSD) of the precision of the PVP method was 0.08%-4.53%, and the average recovery rate for low, medium, and high concentrations was 97.23%-99.68%. The RSD of the precision of the DMAC method was 0.12%-3.72%, and the average recovery rate for low, medium, and high concentrations was 92.10%-99.37%.

[0153] Comparative Example 1:

[0154] Column conditions:

[0155] The chromatographic column was a C18 column (250 mm × 4.6 mm, 5 μm).

[0156] Detection wavelength: 205nm;

[0157] Mobile phase: methanol:water (volume ratio = 40:60);

[0158] Mobile phase flow rate: 0.5 mL / min;

[0159] Injection volume: 20 μL;

[0160] The detection time is 40 minutes;

[0161] The test spectrum of Comparative Example 1 is as follows Figure 7 As shown, by Figure 7 It can be seen that increasing the proportion of methanol greatly accelerated the elution of PVP and DMAC, causing both PVP and DMAC to be eluted around 5-7 min. The peak resolution of the sample was less than 1.5, and they could not be separated. The peak shapes of the two could not be distinguished.

[0162] Comparative Example 2:

[0163] Column conditions:

[0164] The chromatographic column was a C18 column (250 mm × 4.6 mm, 5 μm).

[0165] Detection wavelength: 205nm

[0166] Mobile phase: Acetonitrile: Potassium dihydrogen phosphate buffer solution at pH 2.5 (volume ratio = 5:95)

[0167] Mobile phase flow rate: 0.5 mL / min

[0168] Injection volume: 20 μL

[0169] The detection time is 40 minutes.

[0170] In Example 1, the retention time of the PVP (K85) spectrum was approximately 16.10 min, and the retention time of the DMAC spectrum was approximately 25.40 min.

[0171] The test spectrum of Comparative Example 2 is as follows Figure 8 As shown, by Figure 8 As can be seen from 'a', PVP cannot maintain an independent peak shape in this mobile phase, merging with impurity peaks into a broad peak that eluted at 11.368 min, leading to inaccurate test results. Figure 8 As can be seen from b, DMAC peaks at 14.859 min.

[0172] Comparative Example 3: (Testing PVPK30 and DMAC)

[0173] Chromatographic column: C18 reversed-phase column, ODS-4 5μm, 4.6×250mm (UP)

[0174] Detection wavelength: 205nm

[0175] Column temperature: 30℃

[0176] Injection volume: 20 μL

[0177] Mobile phase: Acetonitrile-water solution (volume ratio 5:95)

[0178] Washing method: isocratic washing

[0179] Mobile phase flow rate: 1.0 mL / min

[0180] Test results are as follows Figure 9 As shown, Figure 9 The peak shapes of the spectral samples of the Chinese standard PVPK30 and DMAC overlapped in a sample with a flow rate of 400.

[0181] Test results:

[0182] Using the chromatographic column conditions of Example 1, multiple samples were tested for leachability, and the results are as follows:

[0183] Table 8 Summary of PVP Results for Leachable Material Test

[0184]

[0185] By comparing the peak area of ​​the sample test with the peak area of ​​50ug / mL PVP, it was found that the PVP content of the three samples was lower than the safety limit and met the quality requirements.

[0186] Table 9 Summary of DMAC Calculation Results for Leachable Material Test

[0187]

[0188] The DMAC content under different test conditions was obtained by standard curve. The DMAC content of all three samples was lower than the safety limit and met the quality requirements.

[0189] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for detecting and evaluating the PVP and DMAC of leachable materials in a hollow fiber membrane separator, characterized in that, include: A) The hollow fiber membrane separator was extracted with pure water to obtain the test solution; PVP and DMAC were dissolved in pure water to obtain reference solutions. B) The test solution is detected by high performance liquid chromatography to obtain a chromatogram of the test solution; The reference solution was analyzed by high performance liquid chromatography to obtain a chromatogram of the reference; and the components of the test solution were qualitatively and quantitatively analyzed based on the chromatogram of the reference. The chromatographic conditions for the high-performance liquid chromatography method are as follows: The volume ratio of the mobile phase to the methanol-water mixture is (1~20):(80~99).

2. The detection and evaluation method according to claim 1, characterized in that, The test solution is prepared by the following method: the test solution is produced by circulation using a peristaltic pump, and the hollow fiber membrane separator is pre-rinsed with physiological saline before immersion.

3. The detection and evaluation method according to claim 2, characterized in that, The specific method for preparing the test solution is as follows: The circulation pipeline used for the experiment was rinsed with pure water. The hollow fiber membrane separator sample was connected to the circulation pipeline. Physiological saline was used to thoroughly rinse the hollow fiber membrane passage inside the hollow fiber membrane separator at a flow rate of 100~400 mL / min. During this process, a rubber hammer was used to tap and remove air bubbles from the passage. After the physiological saline is fully circulated, the physiological saline in the hollow fiber membrane separator is completely drained. Then, purified water is used as the extraction medium, and the mixture is fully circulated for 4-6 hours at the test flow rate using a peristaltic pump to obtain the test solution.

4. The detection and evaluation method according to claim 1, characterized in that, The chromatographic column is a C18 column with dimensions of 250 mm × 4.6 mm and a diameter of 5 μm. The column temperature is 20–30 °C. The detection wavelength is 190 nm–230 nm.

5. The detection and evaluation method according to claim 1, characterized in that, The flow rate of the mobile phase is 0.5~2.0 mL / min.

6. The detection and evaluation method according to claim 1, characterized in that, The injection volume is 10~40μL.

7. The detection and evaluation method according to claim 1, characterized in that, The chromatographic conditions are as follows: Detection wavelength: 205nm; Mobile phase: methanol:water (volume ratio = 5:95); Mobile phase flow rate: 0.5 mL / min; Injection volume: 20 μL; Detection time: 40 minutes; or Detection wavelength: 190nm; Mobile phase: Methanol:Water (volume ratio = 1:99) Mobile phase flow rate: 1 mL / min; The injection volume was 10 μL. The detection time is 20 minutes; or Detection wavelength: 230nm; Mobile phase: methanol:water (volume ratio = 20:80) Mobile phase flow rate: 1 mL / min Injection volume: 40 μL The detection time is 60 minutes.

8. The detection and evaluation method according to claim 1, characterized in that, The injection concentration of PVP was 25~400 μg / mL. The linear regression equation was: y = 119.89x + 397.93, and the correlation coefficient r was... 2 =0.9709; The injection concentration of DMAC is 1~40 μg / mL. The linear regression equation is: y = 233452x - 17905, and the correlation coefficient r is... 2 =0.9999.

9. The detection and evaluation method according to claim 1, characterized in that, The separation degree of the PVP is greater than 1.5; the separation degree of the DMAC is greater than 1.

5.

10. The detection and evaluation method according to claim 1, characterized in that, The K value of the PVP is 85; the limit of quantitation of DMAC is 0.025 μg / mL.

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