Drug inspection sample preparation method and device

Abstract

The invention discloses a medicine inspection sample preparation method and device, and belongs to the technical field of medicine inspection. According to the method, through the key steps of gradient alkalifying pH linkage control, gradient elution, temperature programming drying quality monitoring, pre-enrichment and the like, accurate treatment of a test solution is realized; the core lies in that a capillary microfluidic analysis chip with a multi-layer composite structure is adopted, the channel size matching and connection design is optimized, and the sample treatment efficiency and purity are improved. The corresponding device integrates an intelligent control system, a pH monitoring module, a laser particle size monitoring module and the like, and full-process automatic control is achieved. The defects that in the prior art, operation is tedious, the automation degree is low, sample loss is large, and a micro-fluidic chip is large in dead volume are overcome, the prepared sample is high in purity and accurate in concentration, the method is suitable for various types of samples to be tested, the accuracy and efficiency of drug inspection can be remarkably improved, and the method has important industrial application value.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical testing technology, and in particular to a method for preparing pharmaceutical testing samples and an apparatus for implementing the method. Background Technology

[0002] Sample preparation is a crucial step in drug testing, as its effectiveness directly impacts the accuracy and reliability of subsequent test results. Current drug testing sample preparation methods often employ traditional step-by-step operations such as centrifugation, extraction, and drying, which suffer from cumbersome procedures, low automation, and significant sample loss. Furthermore, the microfluidic chips used in existing preparation devices are mostly of traditional assembly structures, exhibiting drawbacks such as large dead volume, poor sealing performance, and unsmooth channel connections, easily leading to sample residue and cross-contamination.

[0003] Furthermore, existing methods suffer from poor pH stability in adjusting the test solution, low elution efficiency, and insufficient adaptability to test samples with low concentrations and complex matrices (containing macromolecular impurities such as proteins and polysaccharides). The low precision in controlling parameters such as temperature and flow rate during preparation makes it difficult to guarantee the reproducibility of sample preparation. Therefore, there is an urgent need to develop a highly automated, highly accurate, and widely adaptable method and apparatus for preparing pharmaceutical test samples to address the aforementioned problems in existing technologies. Summary of the Invention

[0004] To address the problems mentioned in the background section, the present invention provides a method and apparatus for preparing drug testing samples.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The method for preparing drug testing samples according to the present invention specifically includes the following steps:

[0007] S1. Intelligent Pretreatment Stage: Prepare a test solution from the drug sample. Use a gradient alkali addition device to add alkaline substances in stages and mix online. The gradient alkali addition rate is adjusted by a real-time pH monitoring module to ensure the system pH remains stable within a preset range (8.5-10.5). Subsequently, an autosampler controls the capillary to draw up the adjusted test solution and precisely inject it into the sample inlet of the capillary microfluidic analysis chip. Elution is performed using a gradient elution strategy (initial mobile phase ratio: ethanol: auxiliary solvent). = 9:1, gradually adjusted to 7:3 with elution time, gradient elution time controlled at 30-60 min), collect the eluent into a sample collection bottle with weighing function; place the sample collection bottle in a constant temperature drying oven and start the programmed temperature rise drying mode: first dry at 37℃ for 2 hours, then rise to 45℃ for 1 hour, and finally cool down to 37℃ and keep warm for 30 minutes; record the mass of the sample collection bottle every 30 minutes during the drying process, and when the difference between two consecutive mass values ​​is ≤0.001g, the drying process is considered stable.

[0008] In this step, the design of gradient alkali addition and pH linkage control can effectively avoid sample denaturation caused by sudden pH changes in the test solution; programmed temperature drying combined with quality monitoring can improve drying uniformity and prevent over-drying from damaging the sample.

[0009] S2. Chip Sample Preparation Stage: Turn on the constant temperature drying oven linkage control module to keep the temperature fluctuation inside the oven ≤ ±0.5℃ and not lower than 37℃. Drive the sample injection valve to accurately connect the micro-sample injection ring and the sample collection bottle through the electric translation stage. At the same time, start the chip channel preheating program to stabilize the internal channel temperature of the capillary microfluidic analysis chip at 37℃.

[0010] This step, through constant temperature linkage control and precise docking design, ensures that the sample and chip channel are in a stable temperature environment, providing temperature assurance for subsequent accurate enrichment, while improving the sealing and accuracy of the sample introduction process.

[0011] S3. Precision Enrichment and Finished Product Stage: After the sample collection bottle is dried to a stable quality, it is moved to the chip injection station. The peristaltic pump is started, and the mobile phase flows through the injection valve into the sample collection bottle at a set flow rate (15-20 μL / min, which can be dynamically fine-tuned according to the viscosity of the sample) through the flow feedback adjustment system, thus reconstituteing the dried sample. The dispersion state of the reconstituted sample is monitored in real time using the laser particle size monitoring module built into the sample collection bottle. When no obvious precipitated substances are detected and the particle size uniformity is ≥95%, the reconstitution process is stopped. Subsequently, the reconstituted sample is introduced into the pre-enrichment channel built into the chip for secondary concentration. The concentration factor can be adjusted within the range of 1-10 times according to the detection requirements. After concentration, the test sample solution is obtained. During the pre-enrichment process, the enrichment effect is monitored in real time by an ultraviolet detector. When the sample concentration reaches the target range, the enrichment is automatically stopped.

[0012] In this step, the combination of flow feedback adjustment and laser particle size monitoring ensures that the sample is fully reconstituted and evenly dispersed; the design of the pre-enrichment channel enables precise concentration of low-concentration samples, expanding the method's adaptability to low-concentration test samples.

[0013] S4. Chip Channel Cleaning and Regeneration Stage: After the sample to be tested is collected, the system automatically switches to the cleaning channel and sequentially introduces ethanol, deionized water, and nitrogen to rinse and dry the capillary microfluidic analysis chip channel and sample introduction system. The entire cleaning process is automated.

[0014] This step, through its automated cleaning design, effectively removes residual samples from the channel, avoids cross-contamination, and provides a clean channel environment for the next sample preparation.

[0015] The core component of this invention is a capillary microfluidic analysis chip, the specific structural design of which is as follows:

[0016] The capillary microfluidic analysis chip adopts a multi-layer composite structure design. The upper layer is the sample introduction and splitting zone, the middle layer is the separation and enrichment zone, and the lower layer is the detection and cleaning zone. The sample introduction channel is located on the inner wall of the capillary and adopts a gradient inner diameter design. The detection channel has a built-in light scattering enhancement coating. The pre-enrichment channel is connected in parallel to one side of the sample collection channel and is switched by a solenoid valve. The sample introduction channel, sample outlet, and sample inlet are all 45° beveled. The sample introduction channel, detection channel, and pre-enrichment channel are all modified capillaries. The microfluidic inner diameter (50-80μm) of the sample introduction channel is smaller than that of the sample introduction loop (100-120μm), the outer diameter of the sample introduction loop (150-180μm) is larger than that of the detection channel (80-100μm), and the outer diameter of the sample introduction loop is equal to that of the inner diameter of the capillary (150-180μm). The connection between each channel adopts a smooth transition design, and the taper of the transition section is ≤5°.

[0017] The precise matching of the multi-layered composite structure and channel size can reduce chip dead volume and sample residue, and improve sealing performance; the design of 45° bevel and modified capillary further reduces the risk of sample adsorption and residue, ensuring the accuracy of sample processing.

[0018] Furthermore, the alkaline substance is a sodium hydroxide-disodium hydrogen phosphate buffer system, wherein the mass concentration of sodium hydroxide is 2.5–10 g / L and the mass concentration of disodium hydrogen phosphate is 1–3 g / L; the amount of buffer system added is 5–10% of the volume of the test sample solution, and for alkaline test samples, the amount added is adjusted to 3–5%. This buffer system is chemically stable, can effectively maintain the pH stability of the test sample solution, and will not interfere with the components of the test sample.

[0019] Furthermore, the mobile phase is a mixture of ethanol and isopropanol, with isopropanol added at 1-5%. For samples that are difficult to elute, 0.5-1% Tween 80 is added. The mobile phase is filtered through a 0.22μm organic phase filter membrane and ultrasonically degassed for 15-20 minutes before use, and is prepared fresh each time. The mixed mobile phase design improves elution efficiency, is suitable for samples of different polarities, and the filtration and degassed treatment avoids clogging of the channels and interference with the detection signal by impurities and air bubbles.

[0020] Furthermore, for test samples containing macromolecular impurities such as proteins and polysaccharides, an ultrafiltration pretreatment unit is added after mixing with alkali in step S1, with an ultrafiltration membrane pore size of 0.22 μm; for lipid-soluble test samples, ≤5% dimethyl sulfoxide is added to the test sample solution. Ultrafiltration pretreatment can remove macromolecular impurities and avoid channel blockage; dimethyl sulfoxide, as a solubilizer, can improve the solubility of lipid-soluble test samples and expand the applicability range of the method.

[0021] 2. Drug testing sample preparation device

[0022] Corresponding to the above-mentioned method for preparing drug test samples, the present invention also provides a drug test sample preparation device, including a sample inlet loop, a storage bottle, a peristaltic pump, a peristaltic pump controller, a constant temperature drying oven, a sample collection bottle, a first interface, a second interface, a capillary microfluidic analysis chip, a constant temperature sample inlet valve, a peristaltic pump inlet tube, a sample inlet tube, a micro-sample inlet loop, a solenoid valve, a sample inlet valve control line, a solenoid valve control line, a peristaltic pump control line, a capillary microfluidic analysis chip control line, an intelligent control system, a pH monitoring module, a laser particle size monitoring module, an electric translation stage, a gradient alkali addition device, an ultrafiltration pretreatment unit, a nitrogen purging module, and a multi-layer constant temperature module.

[0023] The connection relationships and functions of each component are as follows:

[0024] The intelligent control system is connected to the peristaltic pump controller, constant temperature drying oven, pH monitoring module, laser particle size monitoring module, electric translation stage, solenoid valve, gradient alkali addition device, ultrafiltration pretreatment unit, nitrogen purging module, and multi-layer constant temperature module via control lines to achieve fully automated control and data acquisition. The storage bottle is a multi-channel storage bottle that stores mobile phase, cleaning solution, and buffer solution respectively, and is connected to the peristaltic pump via a solenoid valve. The peristaltic pump is connected to the peristaltic pump inlet pipe and the peristaltic pump controller, and a flow sensor is installed at the outlet of the peristaltic pump to provide real-time flow data feedback. The gradient alkali addition device is connected in series at the front end of the sample inlet pipe and is linked with the pH monitoring module to achieve precise adjustment of the alkali addition rate. The ultrafiltration pretreatment unit can be selectively connected to the sample injection process via a three-way valve to adapt to different matrices of the test samples. All pipeline connections use dedicated Luer connectors to ensure a leak-free seal. The peristaltic pump inlet and outlet pipes are made of corrosion-resistant PTFE material, with inner diameters matching the corresponding channels.

[0025] The capillary microfluidic analysis chip is embedded in a multi-layer thermostatic module to ensure uniform and stable temperature across all areas of the chip. The nitrogen purging module is connected to the cleaning channel interface of the capillary microfluidic analysis chip and the sample collection bottle via a diverter valve, enabling channel cleaning and removal of residues after sample drying. The sample collection bottle incorporates a weighing sensor and a laser particle size monitoring module to monitor mass changes during the drying process and the particle state after reconstitution in real time. The multi-layer thermostatic module includes a chip thermostatic zone, a sample injection valve thermostatic zone, and a sample collection thermostatic zone, with each zone's temperature independently adjustable.

[0026] Furthermore, the capillary microfluidic analysis chip employs a 3D printing integrated molding process, avoiding leakage and dead volume problems associated with traditional assembly. The chip material is modified polydimethylsiloxane (PDMS), with a surface treated by plasma to enhance hydrophilicity and chemical stability. For strong organic solvent systems, modified polyetheretherketone (PEEK) chips can be used to improve corrosion resistance. The pre-enrichment channel adopts a spiral structure design (spiral diameter 5-8 mm, 3-5 turns) to increase the contact area between the sample and the channel, improving enrichment efficiency. The inner wall of the detection channel is coated with nano-silver particles to enhance light scattering signals and improve subsequent detection sensitivity. Each shunt channel is equipped with a microvalve to achieve independent control and switching of the channel.

[0027] Furthermore, the solenoid valve is a two-position three-way miniature solenoid directional valve with a response time of ≤5ms, small size, and fast switching speed, making it suitable for the precise control of microfluidic systems. The solenoid valve is made of corrosion-resistant stainless steel, which can withstand various organic solvents and buffer solutions. Miniature filters (0.1μm pore size) are installed at the inlet and outlet of the solenoid valve to prevent impurities from entering the valve core and causing jamming. The working pressure range of the solenoid valve matches the system pressure (0.01-0.1MPa) to avoid damage from overpressure.

[0028] Furthermore, the intelligent control system integrates a touch screen operating interface and a data storage module, enabling parameter setting, process start-up, status monitoring, data recording, and export functions. The system has a built-in standard method library for various sample types (such as tablets, injections, capsules, etc.), which users can directly call or customize. It supports connection to mobile terminals or computers via wireless communication modules (WiFi / Bluetooth) to achieve remote operation and data viewing, facilitating centralized laboratory management and unattended operation.

[0029] Furthermore, the multi-layer constant temperature module employs a semiconductor cooling / heating element, combined with a temperature sensor to achieve precise temperature control within a range of 25-60℃ with an accuracy of ±0.1℃. Each constant temperature zone is separated by thermal insulation material to prevent temperature interference. The system can automatically adjust the heating / cooling power according to changes in ambient temperature, ensuring the chip and sample remain in a stable temperature environment and improving the repeatability of the preparation process. A thermally conductive silicone pad is added at the contact point between the constant temperature module and the chip to enhance heat transfer efficiency and reduce temperature hysteresis.

[0030] Furthermore, the capillary microfluidic analysis chip fabrication steps include: (1) 3D printing to fabricate a chip mold, mixing modified PDMS prepolymer and curing agent at a ratio of 10:1 and pouring the mixture into the mold, vacuum degassing and constant temperature curing at 80°C for 2 hours, and demolding to obtain a chip substrate; (2) opening a sample injection valve channel and embedding a micro electromagnetic sample injection valve, fixing it with laser welding and then performing a sealing test.

[0031] (3) Laser etching is used to form the sample inlet channel, the detection channel, and the spiral pre-enrichment channel. The inner wall of the detection channel is coated with a nano-silver particle coating. (4) A 45° beveled sample inlet, sample outlet, and various functional interfaces are fabricated and connected to the corresponding pipelines and sensors to complete the fabrication. This fabrication process can ensure the accuracy and stability of the chip structure and improve chip performance.

[0032] (III) Beneficial Effects

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. This invention achieves precise and stable pH adjustment of the test solution through gradient alkali addition and pH linkage control technology, avoiding sample denaturation caused by sudden pH changes. It employs gradient elution combined with programmed temperature drying and quality monitoring to improve elution thoroughness and drying uniformity, reducing sample loss. The addition of pre-enrichment and ultrafiltration pretreatment modules adapts to low-concentration and complex matrix samples, expanding the method's applicability. The chip fabrication process is optimized, employing laser etching and plasma deposition technologies to improve chip performance. Simultaneously, corrosion-resistant and high-precision materials are selected for key components, enhancing the device's operational stability and lifespan.

[0035] 2. A multi-layer composite microfluidic chip is integrally formed by 3D printing, with optimized channel size matching and connection design to reduce dead volume and sample residue and improve sealing performance; it integrates an intelligent control system and multiple sensors to realize fully automated control and data acquisition, improving the ease of operation and reproducibility of preparation; it is equipped with multi-channel liquid storage bottles and cleaning channels to realize mobile phase switching and automated chip cleaning, avoiding cross-contamination. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart illustrating the steps of a method for preparing drug testing samples according to the present invention. Detailed Implementation

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] Example 1: Sample preparation for tablet-type drugs

[0041] (1) Preparation of test solution: Take one tablet of a certain drug, grind it into powder, add 50 mL of deionized water, sonicate for 30 min, and filter to obtain the test solution;

[0042] (2) Start the gradient alkali addition device and add the sodium hydroxide-disodium hydrogen phosphate buffer system (sodium hydroxide mass concentration 5 g / L, disodium hydrogen phosphate mass concentration 2 g / L) to the test sample solution in stages. The amount added is 8% of the volume of the test sample solution. The alkali addition rate is adjusted in real time by the pH monitoring module to stabilize the pH of the system at 9.5. Then, the capillary tube is controlled by the autosampler to draw 50 μL of the adjusted test sample solution and inject it into the sample inlet of the capillary microfluidic analysis chip. The gradient elution strategy is adopted. The initial mobile phase ratio is ethanol:isopropanol = 9:1. After elution for 30 min, it is adjusted to 7:3 and eluted for another 20 min. The eluent is collected into the sample collection bottle. The sample collection bottle is placed in the constant temperature drying oven and the temperature rise drying program is started: constant temperature drying at 37℃ for 2 h, drying at 45℃ for 1 h, and holding at 37℃ for 30 min. The mass is recorded every 30 min during the drying process. The drying is stopped when the difference between two consecutive mass values ​​is ≤0.001 g.

[0043] (3) Turn on the constant temperature drying oven linkage control to maintain the temperature inside the oven at 37℃±0.5℃. Drive the injection valve to accurately dock with the sample collection bottle through the electric translation stage, start the chip channel preheating program, and stabilize the temperature inside the chip channel at 37℃.

[0044] (4) Start the peristaltic pump and set the flow rate to 18 μL / min. The mobile phase (ethanol:isopropanol = 8:2) flows through the injection valve into the sample collection bottle to reconstitute the dried sample. Monitor the particle size using the laser particle size monitoring module. Stop the reconstitution when the particle size uniformity is ≥95%. Introduce the reconstituted sample into the pre-enrichment channel and monitor the sample concentration using the UV detector. Stop enrichment when the sample concentration reaches 0.6 g / L to obtain the sample to be tested.

[0045] (5) After the sample to be tested is collected, the system will automatically switch to the cleaning channel and rinse with ethanol and deionized water for 10 minutes each, and then dry with nitrogen for 5 minutes to complete the cleaning.

[0046] (6) The sample to be tested was injected into the high performance liquid chromatograph for detection. The results showed that the sample purity was ≥98% and the RSD of the test results was ≤2%, which met the requirements for drug testing.

[0047] Example 2: Sample preparation for injectable drugs containing protein impurities

[0048] (1) Preparation of test solution: Take 10 mL of a certain injectable drug and use it directly as the test solution;

[0049] (2) Intelligent pretreatment: Start the gradient alkali addition device and add a sodium hydroxide-disodium hydrogen phosphate buffer system (sodium hydroxide mass concentration 8 g / L, disodium hydrogen phosphate mass concentration 3 g / L), the addition amount is 6% of the volume of the test sample solution, so that the pH of the system is stabilized at 10.0; then start the ultrafiltration pretreatment unit (ultrafiltration membrane pore size 0.22 μm) to ultrafilter the test sample solution after adding alkali to remove protein impurities; draw 80 μL of ultrafiltered test sample solution through the autosampler and inject it into the chip sample inlet; adopt a gradient elution strategy, the initial mobile phase ratio is ethanol:isopropanol = 9:1, after elution for 40 min, adjust to 7:3, continue elution for 20 min, and collect the eluent into the sample collection bottle; start the program to heat and dry, the parameters are the same as in Example 1;

[0050] (3) The subsequent sample injection, enrichment and cleaning steps are the same as in Example 1, with a pre-enrichment factor of 5 times to make the concentration of the sample to be tested reach 0.7 g / L;

[0051] (4) Detection and verification: The sample to be tested was injected into the mass spectrometer for detection. The results showed that there were no protein impurities in the sample and the RSD of the detection result was ≤1.8%, which met the requirements for drug testing.

[0052] Example 3: Application of a Simplified Chip

[0053] A simplified capillary microfluidic analysis chip was used for sample preparation of conventional capsule drugs. The steps were the same as in Example 1, except that the pre-enrichment and ultrafiltration pretreatment steps were omitted. The test results showed that the sample purity was ≥97% and the RSD was ≤2.5%, which met the requirements of conventional drug testing.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing drug testing samples, characterized in that: Includes the following steps: S1. Prepare a test solution from the drug sample. Use a gradient alkali addition device to add alkaline substances in stages and mix online. The gradient alkali addition rate is adjusted by a real-time pH monitoring module to ensure the system pH remains stable within a preset range (8.5-10.5). Then, use an autosampler to control the capillary to draw up the adjusted test solution and precisely inject it into the sample inlet of the capillary microfluidic analysis chip. Elution is performed using a gradient elution strategy (initial mobile phase ratio: ethanol: auxiliary solvent = 9:1). The elution ratio was gradually adjusted to 7:3 with the elution time, and the gradient elution time was controlled at 30-60 min. The eluent was collected into a sample collection bottle with a weighing function. The sample collection bottle was placed in a constant temperature drying oven, and the programmed temperature rise drying mode was started: first, it was dried at 37℃ for 2 hours, then the temperature was increased to 45℃ for 1 hour, and finally the temperature was lowered to 37℃ and kept at that temperature for 30 min. The mass of the sample collection bottle was recorded every 30 min during the drying process. When the difference between two consecutive mass measurements was ≤0.001 g, the drying process was considered to be stable. S2. Turn on the constant temperature drying oven linkage control module to keep the temperature fluctuation inside the oven ≤ ±0.5℃ and not lower than 37℃. Drive the injection valve to accurately connect the micro injection ring and the sample collection bottle through the electric translation stage. At the same time, start the chip channel preheating program to stabilize the internal channel temperature of the capillary microfluidic analysis chip at 37℃. S3. After the sample collection bottle has dried to a stable quality, move it to the chip injection station, start the peristaltic pump, and use the flow feedback adjustment system to allow the mobile phase to flow through the injection valve into the sample collection bottle at the set flow rate (15-20 μL / min, which can be dynamically fine-tuned according to the viscosity of the sample), thus reconstituteing the dried sample. The dispersion state of the reconstituted sample is monitored in real time using the built-in laser particle size monitoring module in the sample collection bottle. When no obvious precipitated substances are detected and the particle size uniformity is ≥95%, the reconstitution process is stopped. The reconstituted sample is then introduced into the chip's built-in pre-enrichment channel for secondary concentration. The concentration factor can be adjusted within the range of 1-10 times according to the detection requirements. After concentration, the test sample solution is obtained. During the pre-enrichment process, the enrichment effect is monitored in real time using a UV detector. When the sample concentration reaches the target range, enrichment automatically stops. S4. After the sample to be tested is collected, the system automatically switches to the cleaning channel and sequentially introduces ethanol, deionized water, and nitrogen to rinse and dry the capillary microfluidic analysis chip channel and sample introduction system. The cleaning process is fully automated. The capillary microfluidic analysis chip adopts a multi-layer composite structure design. The upper layer is the sample introduction and splitting zone, the middle layer is the separation and enrichment zone, and the lower layer is the detection and cleaning zone. The sample introduction channel is located on the inner wall of the capillary and adopts a gradient inner diameter design. The detection channel has a built-in light scattering enhancement coating. The pre-enrichment channel is connected in parallel to one side of the sample collection channel and is switched by a solenoid valve. The sample introduction channel, sample outlet, and sample inlet are all 45° beveled. The sample introduction channel, detection channel, and pre-enrichment channel are all modified capillaries. The microfluidic inner diameter (50-80μm) of the sample introduction channel is smaller than that of the sample introduction loop (100-120μm), the outer diameter of the sample introduction loop (150-180μm) is larger than that of the detection channel (80-100μm), and the outer diameter of the sample introduction loop is equal to that of the inner diameter of the capillary (150-180μm). The connection between each channel adopts a smooth transition design, and the taper of the transition section is ≤5°.

2. The method for preparing drug testing samples according to claim 1, characterized in that: The alkaline substance is a sodium hydroxide-disodium hydrogen phosphate buffer system, wherein the mass concentration of sodium hydroxide is 2.5-10 g / L and the mass concentration of disodium hydrogen phosphate is 1-3 g / L; the amount of buffer system added is 5-10% of the volume of the test sample solution, and for alkaline test samples, the amount added is adjusted to 3-5%.

3. The method for preparing drug testing samples according to claim 1, characterized in that: The mobile phase is a mixture of ethanol and isopropanol, with isopropanol added at 1-5%. For samples that are difficult to elute, 0.5-1% Tween 80 is added. The mobile phase is filtered through a 0.22μm organic phase filter membrane and ultrasonically degassed for 15-20 minutes before use, and is prepared and used immediately.

4. The method for preparing drug test samples according to claim 1, characterized in that: For test samples containing macromolecular impurities such as proteins and polysaccharides, an ultrafiltration pretreatment unit is added after mixing with alkali in step S1, with an ultrafiltration membrane pore size of 0.22 μm; for lipid-soluble test samples, ≤5% dimethyl sulfoxide is added to the test sample solution.

5. A pharmaceutical sample preparation apparatus for implementing the method of claim 1, characterized in that: The system includes a sample inlet loop, a storage bottle, a peristaltic pump, a peristaltic pump controller, a constant temperature drying oven, a sample collection bottle, a first interface, a second interface, a capillary microfluidic analysis chip, a constant temperature sample inlet valve, a peristaltic pump inlet tube, a sample inlet tube, a micro-sample inlet loop, a solenoid valve, a sample inlet valve control line, a solenoid valve control line, a peristaltic pump control line, a capillary microfluidic analysis chip control line, an intelligent control system, a pH monitoring module, a laser particle size monitoring module, an electric translation stage, a gradient alkali addition device, an ultrafiltration pretreatment unit, a nitrogen purging module, and a multi-layer constant temperature module. The intelligent control system is connected to each actuator and monitoring module to achieve fully automated control and data acquisition. The storage bottle is a multi-channel storage bottle, a flow sensor is installed at the outlet of the peristaltic pump, the ultrafiltration pretreatment unit is switched via a three-way valve, the capillary microfluidic analysis chip is embedded in the multi-layer constant temperature module, and the sample collection bottle has a built-in weighing sensor and a laser particle size monitoring module.

6. The pharmaceutical sample preparation apparatus according to claim 5, characterized in that: The capillary microfluidic analysis chip is manufactured using a 3D printing integrated molding process and is made of modified polydimethylsiloxane (PDMS) or modified polyether ether ketone (PEEK). The pre-enrichment channel has a spiral structure with a spiral diameter of 5-8 mm and 3-5 turns. The inner wall of the detection channel is coated with a nano-silver particle coating.

7. The pharmaceutical sample preparation apparatus according to claim 5, characterized in that: The solenoid valve is a two-position three-way miniature solenoid directional valve with a response time of ≤5ms and 0.1μm micro filters at the inlet and outlet. The solenoid valve has a working pressure range of 0.01-0.1MPa to adapt to the system pressure requirements.

8. The pharmaceutical sample preparation apparatus according to claim 5, characterized in that: The intelligent control system integrates a touch screen operating interface and a data storage module, and has a built-in standard method library for various sample types such as tablets, injections, and capsules; it supports wireless communication modules (WiFi / Bluetooth) to connect to mobile terminals or computers, enabling remote operation and data viewing.

9. The pharmaceutical sample preparation apparatus according to claim 5, characterized in that: The multi-layer constant temperature module uses a semiconductor cooling / heating chip, with a temperature control range of 25-60℃ and a temperature control accuracy of ±0.1℃. It includes a chip constant temperature zone, a sample injection valve constant temperature zone, and a sample collection constant temperature zone. Each zone is separated by heat insulation material, and the temperature can be independently controlled. A thermally conductive silicone pad is added at the contact point between the constant temperature module and the chip to enhance the heat conduction efficiency.

10. The pharmaceutical sample preparation apparatus according to claim 5, characterized in that: The fabrication steps of the capillary microfluidic analysis chip include: (1) 3D printing chip molds are made by mixing modified PDMS prepolymer and curing agent at a ratio of 10:1 and pouring the mixture into the mold. The mold is then degassed under vacuum and cured at 80°C for 2 hours. The chip substrate is then demolded. (2) A sample injection valve channel was opened and a miniature electromagnetic sample injection valve was embedded. After laser welding and fixing, a sealing test was performed. (3) Laser etching forms a sample inlet channel, a detection channel and a spiral pre-enrichment channel, and the inner wall of the detection channel is coated with a nano-silver particle coating. (4) Process the 45° angled sample inlet, sample outlet and various functional interfaces, connect the corresponding pipelines and sensors to complete the manufacturing.

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