Preparation method of suspending agent containing lambda-cyhalothrin and chlorantraniliprole

Abstract

The invention discloses a preparation method of a suspending agent containing lambda-cyhalothrin and chlorantraniliprole, and relates to the technical field of pesticides. Comprising the following steps: uniformly mixing lambda-cyhalothrin and chlorantraniliprole, adding a hydrogen bond directing agent, adding an ethyl acetate-ethanol mixed solvent, and grinding; the preparation method comprises the following steps: dissolving N-isopropylacrylamide and acryloylated chitosan in water, adding gold nanorods, introducing nitrogen, injecting an initiator, and dialyzing and purifying; dissolving the co-crystallized powder in tetrahydrofuran, dispersing the composite gel in a choline propionate aqueous solution containing polyoxyethylene-polylactic acid, slowly adding the liquid medicine into a gel dispersion liquid, simultaneously carrying out ultrasonic treatment, and dialyzing to obtain a drug-loaded nanogel suspension; respectively adding glycerol and sodium citrate, homogenizing, shearing, adjusting the pH value, filtering with a filter membrane, and sterilizing; liquid medicine is loaded in a temperature-sensitive gel network, and a photothermal conversion material is introduced, so that on-demand release under the triggering of near-infrared light is realized.

Description

Technical Field

[0001] This invention relates to the field of pesticide technology, and in particular to a method for preparing a suspension containing high-efficiency cyhalothrin and chlorantraniliprole. Background Technology

[0002] Chlorantraniliprole works by affecting the nervous system of insects, causing paralysis, while lambda-cyhalothrin works by interfering with nerve conduction. The combination of the two creates a perfect synergy of rapid killing and long-lasting control. For example, after formulation, pests can stop feeding within 30 minutes, and the effect can last for 20 to 30 days. However, existing suspension concentrates containing lambda-cyhalothrin and chlorantraniliprole face three major technical bottlenecks:

[0003] 1. Insufficient physical stability: The melting point of high-efficiency cyhalothrin is only 49.2℃. Traditional suspending agents are prone to Austral curing under hot storage (54℃) or freezing (0℃) conditions, which leads to particle aggregation and sedimentation.

[0004] 2. Uncontrollable release: Although conventional formulations achieve a combination of rapid and sustained effects, they cannot respond to environmental stimuli to achieve precise release, resulting in pesticide utilization rates of less than 40%.

[0005] 3. Compatibility defects: High-efficiency cyhalothrin (which is lipophilic, log P=7.0) and chlorantraniliprole (which is hydrophilic, log P=2.86) have large differences in physicochemical properties, and phase separation is likely to occur when they are compounded. Current technology relies on a large amount of emulsifiers and stabilizers to maintain homogeneity, but this will increase the environmental burden. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing a suspension containing highly efficient cyhalothrin and chlorantraniliprole, thereby achieving at least a partial solution to the above-mentioned problems.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a suspension containing high-efficiency cyhalothrin and chlorantraniliprole, comprising the following steps:

[0008] High-efficiency cyhalothrin and chlorantraniliprole were mixed evenly, and a hydrogen bonding directing agent was added. Ethyl acetate-ethanol mixed solvent was added and the mixture was ground in a ball mill to obtain a co-crystallized powder.

[0009] N-isopropylacrylamide and acrylated chitosan were dissolved in deionized water, gold nanorods were added and stirred evenly, nitrogen gas was introduced, and then an initiator was injected. After the reaction was complete, the mixture was purified by dialysis to obtain a semi-transparent composite gel. The gel has a core-shell structure, with gold nanorods as the core, N-isopropylacrylamide as the temperature-responsive layer, and acrylated chitosan providing positive charge.

[0010] The co-crystallized powder was dissolved in tetrahydrofuran to obtain a drug solution. The composite gel was dispersed in an aqueous solution of choline propionate containing polyoxyethylene-polylactic acid to obtain a gel dispersion. The drug solution was slowly added to the gel dispersion while being sonicated. The tetrahydrofuran was removed by dialysis to obtain a drug-loaded nanogel suspension. During the evaporation of tetrahydrofuran, polyoxyethylene-polylactic acid micelles encapsulated drug molecules and embedded them into the gel network through hydrophobic interactions, which can achieve a drug loading of up to 35%.

[0011] Glycerol and sodium citrate were added separately and placed in a homogenizer for shearing. The pH was then adjusted to 6.5-7.0, and the mixture was filtered through a 0.22μm filter membrane and sterilized to obtain a light purple semi-transparent suspension.

[0012] Furthermore, 5-15 parts of high-efficiency cyhalothrin and 5-20 parts of chlorantraniliprole are mixed evenly, and 0.05-0.15 parts of hydrogen bond directing agent are added. 8-12 parts of ethyl acetate-ethanol mixed solvent are added, and the mixture is placed in a ball mill and ground at 500 rpm for 2 hours.

[0013] Furthermore, 2-4 parts of N-isopropylacrylamide and 1-2 parts of acrylated chitosan were dissolved in deionized water, and 0.01-0.1 parts of gold nanorods were added and stirred evenly. Nitrogen gas was then introduced, and 0.1 parts of initiator were injected. The mixture was reacted at 70°C for 6 hours and then purified by dialysis to obtain a semi-transparent composite gel.

[0014] Furthermore, the co-crystallized powder was dissolved in 20% tetrahydrofuran to obtain a drug solution, and the composite gel was dispersed in an aqueous solution of choline propionate containing polyoxyethylene-polylactic acid to obtain a gel dispersion. The drug solution was added dropwise to the gel dispersion at a rate of 0.2-1 mL / min while being sonicated. The tetrahydrofuran was removed by dialysis to obtain a drug-loaded nanogel suspension.

[0015] Further, 3-5 parts of glycerol and 0.1-0.5 parts of sodium citrate were added and placed in a homogenizer for shearing at 1000 rpm for 5 minutes. The pH was then adjusted to 6.5-7.0, and the mixture was filtered through a 0.22 μm filter membrane and sterilized to obtain a light purple semi-transparent suspension.

[0016] Furthermore, the mass ratio of the high-efficiency cyhalothrin to chlorantraniliprole is 1:(1-2); the mass ratio of the ethyl acetate to ethanol is 1:3.

[0017] Furthermore, the mass ratio of N-isopropylacrylamide to acrylated chitosan is 3:1;

[0018] The gold nanorods have a diameter of 10 nm and an aspect ratio of 4:1. The surface of the gold nanorods is modified with silicon oxide to increase compatibility.

[0019] Furthermore, the volume ratio of the composite gel in the gel dispersion to the choline propionate aqueous solution containing polyoxyethylene-polylactic acid is 1:10.

[0020] On the other hand, the present invention also provides a suspension containing high-efficiency cyhalothrin and chlorantraniliprole, the suspension being prepared according to the above preparation method.

[0021] On the other hand, the present invention also provides an application of a suspension containing high-efficiency cyhalothrin and chlorantraniliprole, wherein the suspension prepared according to the above preparation method is used in the field of pesticides.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] This invention loads pesticides into a temperature-sensitive gel network and introduces a photothermal conversion material. The gold nanorods generate surface plasmon resonance under 808nm laser irradiation, achieving a photothermal conversion efficiency of 95%. Within 5 minutes, the system temperature rises from 25°C to 45°C. When the temperature exceeds the low critical dissolution temperature of PNIPAM (i.e., LCST = 32°C), the hydrophilicity changes to hydrophobicity, the gel volume shrinks by 80%, and the internally encapsulated drug is extruded. At high temperature, sodium citrate dissociates, the system pH drops from 7.0 to 6.2, the degree of protonation of chitosan amino groups increases, the positive charge density of the gel increases, and electrostatic repulsion promotes drug diffusion, thereby achieving on-demand release triggered by near-infrared light. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] This invention provides a method for preparing a suspension containing high-efficiency cyhalothrin and chlorantraniliprole, comprising the following steps:

[0026] High-efficiency cyhalothrin and chlorantraniliprole were mixed evenly and a hydrogen bond directing agent was added. Ethyl acetate-ethanol mixed solvent was added and the mixture was ground in a ball mill to obtain a co-crystallized powder. The co-crystallization formed a stable structure through intermolecular hydrogen bonds (amide C=O…HO-pyrethrin) and π-π stacking, which solved the problems of melting point and polarity difference.

[0027] N-isopropylacrylamide and acrylated chitosan were dissolved in deionized water, gold nanorods were added and stirred evenly, nitrogen gas was introduced, and then an initiator was injected. After the reaction was complete, the mixture was purified by dialysis to obtain a translucent composite gel.

[0028] The co-crystallized powder was dissolved in tetrahydrofuran to obtain a drug solution. The composite gel was dispersed in an aqueous solution of choline propionate containing polyoxyethylene-polylactic acid to obtain a gel dispersion. The drug solution was slowly added to the gel dispersion while being sonicated. The tetrahydrofuran was removed by dialysis to obtain a drug-loaded nanogel suspension.

[0029] Glycerol and sodium citrate were added separately and placed in a homogenizer for shearing. The pH was then adjusted to 6.5-7.0, and the mixture was filtered through a 0.22μm filter membrane and sterilized to obtain a light purple semi-transparent suspension.

[0030] In a further embodiment of this example, 5-15 parts of high-efficiency cyhalothrin and 5-20 parts of chlorantraniliprole are mixed evenly, and 0.05-0.15 parts of hydrogen bond directing agent are added. 8-12 parts of ethyl acetate-ethanol mixed solvent are added, and the mixture is placed in a ball mill and ground at 500 rpm for 2 hours. The hydrogen bond directing agent is 4-carboxyphenylboronic acid. If the amount of 4-carboxyphenylboronic acid is too low, the crystal form will be impure; if the amount is too high, the grinding viscosity will increase. If the ball mill speed is too low, the crystallinity will be insufficient; if the speed is too high, the raw material will melt due to excessive temperature during the grinding process.

[0031] In a further embodiment of this example, 2-4 parts of N-isopropylacrylamide and 1-2 parts of acrylated chitosan are dissolved in deionized water. 0.01-0.1 parts of gold nanorods are added and stirred evenly. Nitrogen gas is then introduced, followed by the injection of 0.1 parts of initiator. The reaction is carried out at 70°C for 6 hours and then purified by dialysis to obtain a semi-transparent composite gel. If the amount of gold nanorods added is too low, the efficiency during heating will be low, while if it is too high, it will cause the gel to aggregate and affect the quality of the suspension. If the amount of initiator is too low, it will affect the conversion efficiency of the conversion reaction, while if it is too high, it will generate homopolymer impurities during the conversion reaction.

[0032] In a further embodiment of this example, the co-crystallized powder is dissolved in tetrahydrofuran at a mass concentration of 20% to obtain a drug solution. If the concentration of tetrahydrofuran is too low, it will cause premature aggregation and shrinkage, while if the concentration is too high, it will reduce the encapsulation efficiency of the drug. The composite gel is dispersed in an aqueous solution of choline propionate containing polyoxyethylene-polylactic acid to obtain a gel dispersion, wherein the mass concentration of polyoxyethylene-polylactic acid is 4-7%. If the concentration is <4%, the steric hindrance is insufficient; if it is >7%, the viscosity will be too high. The drug solution is added dropwise to the gel dispersion at a rate of 0.2-1 mL / min while being sonicated. If the drop rate is too high, the process will take too long and the efficiency will be reduced. If the drop rate is too high, drug crystal nuclei will be generated during the drop process. The tetrahydrofuran is removed by dialysis to obtain a drug-loaded nanogel suspension.

[0033] In a further embodiment of this example, 3-5 parts of glycerol and 0.1-0.5 parts of sodium citrate were added and placed in a homogenizer and sheared at 1000 rpm for 5 minutes. The pH was then adjusted to 6.5-7.0, and the mixture was filtered through a 0.22 μm filter membrane and sterilized to obtain a light purple semi-transparent suspension.

[0034] In a further embodiment of this example, the mass ratio of the high-efficiency cyhalothrin to chlorantraniliprole is 1:(1-2). When the mass ratio is <1:1, the risk of pyrethroid crystallization is high; when the mass ratio is >1:3, the eutectic melting point decreases. The mass ratio of ethyl acetate to ethanol is 1:3 to control solvent polarity and promote the formation of intermolecular hydrogen bonds.

[0035] In a further embodiment of this example, the mass ratio of N-isopropylacrylamide to acrylated chitosan is 3:1, and this mass ratio determines the lower critical dissolution temperature.

[0036] The gold nanorods have a diameter of 10 nm and an aspect ratio of 4:1. The surface of the gold nanorods is modified with silicon oxide to increase compatibility.

[0037] In a further embodiment of this example, the volume ratio of the composite gel in the gel dispersion to the choline propionate aqueous solution containing polyoxyethylene-polylactic acid is 1:10.

[0038] On the other hand, embodiments of the present invention also provide a suspension containing high-efficiency cyhalothrin and chlorantraniliprole, the suspension prepared according to the above preparation method.

[0039] On the other hand, embodiments of the present invention also provide an application of a suspension containing high-efficiency cyhalothrin and chlorantraniliprole, wherein the suspension prepared according to the above preparation method is used in the field of pesticides.

[0040] It should be noted that this invention loads pesticides into a temperature-sensitive gel network and introduces photothermal conversion materials. The gold nanorods generate surface plasmon resonance under 808nm laser irradiation, achieving a photothermal conversion efficiency of 95%. Within 5 minutes, the system temperature rises from 25℃ to 45℃. When the temperature exceeds the low critical dissolution temperature of PNIPAM (i.e., LCST=32℃), the hydrophilicity changes to hydrophobicity, the gel volume shrinks by 80%, and the internally encapsulated drug is squeezed out. At high temperature, sodium citrate dissociates, the system pH drops from 7.0 to 6.2, the degree of protonation of chitosan amino groups increases, the positive charge density of the gel increases, and electrostatic repulsion promotes drug diffusion, thereby achieving on-demand release triggered by near-infrared light and achieving a cascade effect of photothermal-temperature-phase transition triple response.

[0041] Compared with traditional compound preparations, the embodiments of the present invention achieve dual spatial-temporal synergy:

[0042] Spatial synergy: The co-crystallization structure ensures that highly efficient cyhalothrin (target: sodium ion channel) and chlorantraniliprole (target: ryanodine receptor) are delivered simultaneously to the same insect body;

[0043] Timing synergy: Before light exposure, chlorantraniliprole is slowly released (mainly for stomach poisoning); after light exposure, lambda-cyhalothrin is rapidly released (mainly for contact killing), achieving a "stomach poisoning first, then contact killing" sequential effect.

[0044] Furthermore, this invention addresses the problem of physical instability through multiple stabilization barriers:

[0045] Electrostatic repulsion layer: Chitosan carries a positive charge (+25mV) at pH>6.0, forming an electric double layer with the negative charge (-15mV) of polyoxyethylene-polylactic acid; Steric hindrance layer: Hydrophilic polyoxyethylene chains in polyoxyethylene-polylactic acid form a 10nm thick hydration layer, inhibiting gel collisions; Antifreeze protective layer: Glycerol forms a hydrogen bond network with water molecules, inhibiting ice crystal growth and preventing freezing at -4℃; Crystallization inhibition layer: Choline ionic liquid disrupts the cluster structure of water molecules, reducing the supersaturation of lambda-cyhalothrin.

[0046] Example 1

[0047] Ten parts of high-efficiency cyhalothrin and 15 parts of chlorantraniliprole were mixed evenly, and 0.1 parts of a hydrogen bond directing agent, 4-carboxyphenylboronic acid, were added. Ten parts of a mixed solvent of ethyl acetate and ethanol (mass ratio 1:3) were added, and the mixture was milled in a ball mill at 500 rpm for 2 hours. The resulting co-crystal was a new crystal form of space group P21 / c, with a melting point increased to 83.5℃.

[0048] Three parts of N-isopropylacrylamide and one part of acrylated chitosan were dissolved in deionized water. 0.01 parts of gold nanorods were added and stirred evenly. Nitrogen gas was then introduced, followed by the injection of 0.1 parts of potassium persulfate as an initiator. The mixture was reacted at 70°C for 6 hours and then purified by dialysis to obtain a semi-transparent composite gel.

[0049] The co-crystallized powder was dissolved in 20% tetrahydrofuran to obtain a drug solution. The composite gel was dispersed in an aqueous solution of choline propionate containing polyoxyethylene-polylactic acid to obtain a gel dispersion, wherein the mass concentration of polyoxyethylene-polylactic acid was 5%. The drug solution was added dropwise to the gel dispersion at a rate of 0.2 mL / min while being sonicated. The volume ratio of the drug solution to the gel dispersion was 1:10. The tetrahydrofuran was removed by dialysis to obtain a drug-loaded nanogel suspension.

[0050] Five parts of glycerol and 0.3 parts of sodium citrate were added to the homogenizer and sheared at 1000 rpm for 5 min. The pH was then adjusted to 6.5-7.0, and the mixture was filtered through a 0.22 μm filter membrane and sterilized to obtain a light purple semi-transparent suspension.

[0051] Example 2

[0052] Ten parts of high-efficiency cyhalothrin and 15 parts of chlorantraniliprole were mixed evenly, and 0.1 parts of a hydrogen bond directing agent, 4-carboxyphenylboronic acid, were added. Ten parts of a mixed solvent of ethyl acetate and ethanol (mass ratio 1:3) were added, and the mixture was milled in a ball mill at 500 rpm for 2 hours. The resulting co-crystal was a new crystal form of space group P21 / c, with a melting point increased to 83.5℃.

[0053] Three parts of N-isopropylacrylamide and one part of acrylated chitosan were dissolved in deionized water. 0.05 parts of gold nanorods were added and stirred evenly. Nitrogen gas was then introduced, followed by the injection of 0.1 parts of potassium persulfate as an initiator. The mixture was reacted at 70°C for 6 hours and then purified by dialysis to obtain a semi-transparent composite gel.

[0054] The co-crystallized powder was dissolved in 20% tetrahydrofuran to obtain a drug solution. The composite gel was dispersed in an aqueous solution of choline propionate containing polyoxyethylene-polylactic acid to obtain a gel dispersion, wherein the mass concentration of polyoxyethylene-polylactic acid was 5%. The drug solution was added dropwise to the gel dispersion at a rate of 0.2 mL / min while being sonicated. The volume ratio of the drug solution to the gel dispersion was 1:10. The tetrahydrofuran was removed by dialysis to obtain a drug-loaded nanogel suspension.

[0055] Five parts of glycerol and 0.3 parts of sodium citrate were added to the homogenizer and sheared at 1000 rpm for 5 min. The pH was then adjusted to 6.5-7.0, and the mixture was filtered through a 0.22 μm filter membrane and sterilized to obtain a light purple semi-transparent suspension.

[0056] Example 3

[0057] Ten parts of high-efficiency cyhalothrin and 15 parts of chlorantraniliprole were mixed evenly, and 0.1 parts of a hydrogen bond directing agent, 4-carboxyphenylboronic acid, were added. Ten parts of a mixed solvent of ethyl acetate and ethanol (mass ratio 1:3) were added, and the mixture was milled in a ball mill at 500 rpm for 2 hours. The resulting co-crystal was a new crystal form of space group P21 / c, with a melting point increased to 83.5℃.

[0058] Three parts of N-isopropylacrylamide and one part of acrylated chitosan were dissolved in deionized water. 0.1 parts of gold nanorods were added and stirred evenly. Nitrogen gas was then introduced, followed by the injection of 0.1 parts of potassium persulfate as an initiator. The mixture was reacted at 70°C for 6 hours and then purified by dialysis to obtain a semi-transparent composite gel.

[0059] The co-crystallized powder was dissolved in 20% tetrahydrofuran to obtain a drug solution. The composite gel was dispersed in an aqueous solution of choline propionate containing polyoxyethylene-polylactic acid to obtain a gel dispersion, wherein the mass concentration of polyoxyethylene-polylactic acid was 5%. The drug solution was added dropwise to the gel dispersion at a rate of 0.2 mL / min while being sonicated. The volume ratio of the drug solution to the gel dispersion was 1:10. The tetrahydrofuran was removed by dialysis to obtain a drug-loaded nanogel suspension.

[0060] Five parts of glycerol and 0.3 parts of sodium citrate were added to the homogenizer and sheared at 1000 rpm for 5 min. The pH was then adjusted to 6.5-7.0, and the mixture was filtered through a 0.22 μm filter membrane and sterilized to obtain a light purple semi-transparent suspension.

[0061] The suspensions prepared in Examples 1-3 were tested experimentally. 1 mL of each suspension (Example 1, Example 2, and Example 3) was placed in a cuvette, fixed at the center of the laser path, and the initial temperature (T0) was recorded using an infrared thermal imager. Laser irradiation was performed for 5 minutes, with temperature recorded every second. The laser was then turned off, and the cooling curve was recorded for another 5 minutes. The 5-minute temperature rise was calculated using the formula T. max -T0 is calculated, where T max The peak temperature after 5 minutes of irradiation is given by the formula for calculating the photothermal conversion efficiency:

[0062]

[0063] Where η is the photothermal conversion efficiency (%); h is the heat transfer coefficient (W / (m²·K)); and S is the sample surface area (cm²). 2 ); T amb Ambient temperature (°C); Q0 is background heat dissipation (W); I is laser power (W); This represents the absorbance. The obtained data are shown in Table 1 below:

[0064] Table 1

[0065] 5-minute temperature rise value Photothermal conversion efficiency Example 1 12.3℃ 63% Example 2 20.1℃ 92% Example 3 22.5℃ 95%

[0066] Take 1 mL of the suspension obtained in Example 3 and place it into a dialysis bag. Immerse the bag in 200 mL of pH 7.0 phosphate buffer. Irradiate the dialysis bag area with an 808 nm laser (1 W / cm²) for 5 min. Take 1 mL samples before irradiation (t=0) and at 1, 3, and 5 min after irradiation for HPLC analysis to determine the drug concentration. Calculate the cumulative release rate at different irradiation times using the following formula:

[0067]

[0068] Where n is the number of samplings; C iV represents the concentration (mg / mL) measured in the i-th sample; V is the volume (mL) of each sample. 补 To replenish volume (mL); C n The concentration (mg / mL) measured at the last sampling point; M 总 Total drug loading (mg); ∑ n i= 1C i •V represents the cumulative release (mg).

[0069] The calculation results show that the cumulative release rate is 5.2% when the irradiation time is 0 minutes, increases to 38.7% after 1 minute of irradiation, increases to 76.5% after 3 minutes of irradiation, and increases to 93.1% after 5 minutes of irradiation. Therefore, this suspending agent can achieve a cumulative release rate of more than 90% after 5 minutes of laser irradiation.

[0070] Example 4

[0071] Ten parts of high-efficiency cyhalothrin and 15 parts of chlorantraniliprole were mixed evenly, and 0.1 parts of a hydrogen bond directing agent, 4-carboxyphenylboronic acid, were added. Ten parts of a mixed solvent of ethyl acetate and ethanol (mass ratio 1:3) were added, and the mixture was milled in a ball mill at 500 rpm for 2 hours. The resulting co-crystal was a new crystal form of space group P21 / c, with a melting point increased to 83.5℃.

[0072] Three parts of N-isopropylacrylamide and one part of acrylated chitosan were dissolved in deionized water. 0.1 parts of gold nanorods were added and stirred evenly. Nitrogen gas was then introduced, followed by the injection of 0.1 parts of potassium persulfate as an initiator. The mixture was reacted at 70°C for 6 hours and then purified by dialysis to obtain a semi-transparent composite gel.

[0073] The co-crystallized powder was dissolved in 20% tetrahydrofuran to obtain a drug solution. The composite gel was dispersed in an aqueous solution of choline propionate containing polyoxyethylene-polylactic acid to obtain a gel dispersion, wherein the mass concentration of polyoxyethylene-polylactic acid was 5%. The drug solution was added dropwise to the gel dispersion at a rate of 0.5 mL / min while being sonicated. The volume ratio of the drug solution to the gel dispersion was 1:10. The tetrahydrofuran was removed by dialysis to obtain a drug-loaded nanogel suspension.

[0074] Five parts of glycerol and 0.3 parts of sodium citrate were added to the homogenizer and sheared at 1000 rpm for 5 min. The pH was then adjusted to 6.5-7.0, and the mixture was filtered through a 0.22 μm filter membrane and sterilized to obtain a light purple semi-transparent suspension.

[0075] Example 5

[0076] Ten parts of high-efficiency cyhalothrin and 15 parts of chlorantraniliprole were mixed evenly, and 0.1 parts of a hydrogen bond directing agent, 4-carboxyphenylboronic acid, were added. Ten parts of a mixed solvent of ethyl acetate and ethanol (mass ratio 1:3) were added, and the mixture was milled in a ball mill at 500 rpm for 2 hours. The resulting co-crystal was a new crystal form of space group P21 / c, with a melting point increased to 83.5℃.

[0077] Three parts of N-isopropylacrylamide and one part of acrylated chitosan were dissolved in deionized water. 0.1 parts of gold nanorods were added and stirred evenly. Nitrogen gas was then introduced, followed by the injection of 0.1 parts of potassium persulfate as an initiator. The mixture was reacted at 70°C for 6 hours and then purified by dialysis to obtain a semi-transparent composite gel.

[0078] The co-crystallized powder was dissolved in 20% tetrahydrofuran to obtain a drug solution. The composite gel was dispersed in an aqueous solution of choline propionate containing polyoxyethylene-polylactic acid to obtain a gel dispersion, wherein the mass concentration of polyoxyethylene-polylactic acid was 5%. The drug solution was added dropwise to the gel dispersion at a rate of 1 mL / min while being sonicated. The volume ratio of the drug solution to the gel dispersion was 1:10. The tetrahydrofuran was removed by dialysis to obtain a drug-loaded nanogel suspension.

[0079] Five parts of glycerol and 0.3 parts of sodium citrate were added to the homogenizer and sheared at 1000 rpm for 5 min. The pH was then adjusted to 6.5-7.0, and the mixture was filtered through a 0.22 μm filter membrane and sterilized to obtain a light purple semi-transparent suspension.

[0080] The drug loading and encapsulation efficiency of the suspensions prepared in Examples 3, 4, and 5 were tested, and the results are shown in Table 2 below:

[0081] Table 2

[0082] Drug loading Encapsulation rate Particle size PDI Example 3 28.1% 91.3% 0.18 Example 4 32.7% 95.6% 0.21 Example 5 24.9% 80.2% 0.37

[0083] As shown in Table 2 above, the drop rate of 0.5 mL / min in Example 4 provides the best cost-effectiveness.

[0084] A field simulation release experiment was conducted on the suspension prepared in Example 4. The experimental conditions were as follows:

[0085] Irradiation: Irradiate with 808nm laser (1W / cm²) for 5 minutes;

[0086] Environment: 25℃ / 60% RH (simulated daytime), 15℃ / 90% RH (simulated nighttime);

[0087] Substrate: Litchi leaves (wax layer thickness 1.2μm).

[0088] The experimental results are shown in Table 3 below:

[0089] Table 3

[0090] Time point Leaf surface retention rate Epidermal penetration xylem conductivity Before light 85.3% 9.2% 5.5% 5 minutes after light exposure 32.7% 51.6% 15.7% 24 hours after light exposure 18.9% 63.4% 17.7%

[0091] Light exposure triggers gel contraction, releasing the drug in the form of nanodroplets (particle size <100nm), which rapidly penetrate through the leaf stomata (pore size 5-10μm).

[0092] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing a suspension containing high-efficiency cyhalothrin and chlorantraniliprole, characterized in that, Includes the following steps: High-efficiency cyhalothrin and chlorantraniliprole were mixed evenly, and a hydrogen bonding directing agent was added. Ethyl acetate-ethanol mixed solvent was added and the mixture was ground in a ball mill to obtain a co-crystallized powder. N-isopropylacrylamide and acrylated chitosan were dissolved in deionized water, gold nanorods were added and stirred evenly, nitrogen gas was introduced, and then an initiator was injected. After the reaction was complete, the mixture was purified by dialysis to obtain a translucent composite gel. The co-crystallized powder was dissolved in tetrahydrofuran to obtain a drug solution. The composite gel was dispersed in an aqueous solution of choline propionate containing polyoxyethylene-polylactic acid to obtain a gel dispersion. The drug solution was slowly added to the gel dispersion while being sonicated. The tetrahydrofuran was removed by dialysis to obtain a drug-loaded nanogel suspension. Glycerol and sodium citrate were added separately and placed in a homogenizer for shearing. The pH was then adjusted to 6.5-7.0, and the mixture was filtered through a 0.22μm filter membrane and sterilized to obtain a light purple semi-transparent suspension.

2. The method for preparing a suspension containing high-efficiency cyhalothrin and chlorantraniliprole according to claim 1, characterized in that: Mix 5-15 parts of high-efficiency cyhalothrin and 5-20 parts of chlorantraniliprole evenly, add 0.05-0.15 parts of hydrogen bond directing agent, add 8-12 parts of ethyl acetate-ethanol mixed solvent, and place in a ball mill and grind at 500 rpm for 2 hours.

3. The method for preparing a suspension containing high-efficiency cyhalothrin and chlorantraniliprole according to claim 1, characterized in that: Dissolve 2-4 parts of N-isopropylacrylamide and 1-2 parts of acrylated chitosan in deionized water, add 0.01-0.1 parts of gold nanorods, stir evenly, then introduce nitrogen gas, and then inject 0.1 parts of initiator. React at 70℃ for 6 hours, and then purify by dialysis to obtain a translucent composite gel.

4. The method for preparing a suspension containing high-efficiency cyhalothrin and chlorantraniliprole according to claim 1, characterized in that: The co-crystallized powder was dissolved in 20% tetrahydrofuran to obtain a drug solution. The composite gel was dispersed in an aqueous solution of choline propionate containing polyoxyethylene-polylactic acid to obtain a gel dispersion. The drug solution was added dropwise to the gel dispersion at a rate of 0.2-1 mL / min while being sonicated. The tetrahydrofuran was removed by dialysis to obtain a drug-loaded nanogel suspension.

5. The method for preparing a suspension containing high-efficiency cyhalothrin and chlorantraniliprole according to claim 1, characterized in that: Add 3-5 parts of glycerol and 0.1-0.5 parts of sodium citrate respectively, and place them in a homogenizer for shearing at 1000 rpm for 5 min. Adjust the pH to 6.5-7.0, then filter through a 0.22 μm filter membrane and sterilize to obtain a light purple semi-transparent suspension.

6. The method for preparing a suspension containing high-efficiency cyhalothrin and chlorantraniliprole according to claim 1 or 2, characterized in that: The mass ratio of the high-efficiency cyhalothrin to chlorantraniliprole is 1:(1-2); the mass ratio of the ethyl acetate to ethanol is 1:

3.

7. The method for preparing a suspension containing high-efficiency cyhalothrin and chlorantraniliprole according to claim 1 or 3, characterized in that: The mass ratio of N-isopropylacrylamide to acrylated chitosan is 3:1; The gold nanorods have a diameter of 10 nm and an aspect ratio of 4:

1. The surface of the gold nanorods is modified with silicon oxide to increase compatibility.

8. The method for preparing a suspension containing high-efficiency cyhalothrin and chlorantraniliprole according to claim 1 or 4, characterized in that: The volume ratio of the composite gel in the gel dispersion to the choline propionate aqueous solution containing polyoxyethylene-polylactic acid is 1:

10.

9. A suspension containing high-efficiency cyhalothrin and chlorantraniliprole, characterized in that, The suspension prepared according to any one of claims 1-8.

10. The application of a suspension containing highly efficient cyhalothrin and chlorantraniliprole, characterized in that, The suspension prepared according to any one of claims 1-8 is used in the field of pesticides.

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