Temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nano-pesticide and preparation method thereof

Abstract

The invention discloses a temperature response type emamectin benzoate-nitenpyram co-delivery liposome nano pesticide and a preparation method thereof. The compound emamectin benzoate and nitenpyram tablet is prepared from the following raw materials: 10%-40% of emamectin benzoate, 10%-40% of nitenpyram, 15%-50% of hydrogenated lecithin, 2%-35% of cholesterol and 1%-25% of a temperature-sensitive material, and the temperature-sensitive material is a decanoic acid-stearic acid binary fatty acid eutectic mixture. Compared with a conventional preparation, the temperature response type emamectin benzoate-nitenpyram co-delivery liposome nano pesticide provided by the invention shows excellent leaf surface wettability and lower toxicity to zebra fish. Indoor biological activity experiments show that the control effect of the nano-pesticide on the plutella xylostella is improved along with temperature rise and is consistent with the population growth trend of the plutella xylostella, and emamectin benzoate and nitenpyram in the nano-pesticide have a synergistic effect in the control of the plutella xylostella.

Description

Technical Field

[0001] The invention belongs to the field of pesticide preparations, and particularly relates to a temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide and a preparation method thereof. Background Art

[0002] Traditional pesticide formulations have large drug-carrying particles, poor dispersibility, and low bioavailability. Nanoparticles have small size effects, interface effects, and high permeability effects. Nanocarriers can load pesticides by adsorption, coupling, encapsulation, inlaying, etc., improve the stability of active ingredients, promote target deposition and dose transfer, and reduce loss. The complementarity of the action mode and mechanism of each active ingredient in the mixed formulation can make the mixed formulation show a synergistic effect. However, the tank mixing operation requires high labor costs, and the scope of application is restricted. In addition, hydrophilic and hydrophobic pesticides are difficult to mix uniformly due to their significant differences in solubility in water, which easily leads to uneven liquid and pesticide damage. Therefore, the development of hydrophilic-hydrophobic co-carrying pesticide formulations is imminent. In addition, traditional pesticide formulations have poor targeting, resulting in waste and loss of pesticides. The combination of nanotechnology and environmental response release function can effectively improve the targeting and bioavailability of pesticides, thereby improving the biological control effect of the formulation and reducing environmental pollution. Among a series of environmental stimuli, temperature is an important factor affecting the occurrence and population size of pests. The population size of most pests gradually increases with rising temperature. Therefore, constructing a high-temperature responsive nanopesticide system is an effective and feasible technical means to achieve intelligent pest control.

[0003] Due to the differences in solubility properties, it is difficult to achieve simultaneous and efficient loading of hydrophobic drugs and hydrophilic drugs in one system. There are few reports of nanopesticide systems that can simultaneously load two pesticides with different hydrophilicity and hydrophobicity and achieve temperature response function.

[0004] Liposomes are microscopic spherical vesicles composed of phospholipid molecules, which can effectively encapsulate both hydrophilic and hydrophobic compounds. Phospholipid molecules are the main components of cell membranes and have high biocompatibility, degradability and safety. Introducing thermosensitive molecules into the liposome membrane can achieve the regulation of liposome functions, thereby constructing temperature-responsive liposomes based on thermosensitive materials. Temperature-responsive liposomes can change their structure according to the ambient temperature, thereby achieving controlled release of drugs. At present, there are no reports on the use of fatty acid eutectic mixtures as thermosensitive molecules encapsulated in liposome phospholipid membranes to construct temperature-responsive pesticide systems.

[0005] Emamectin benzoate and nitenpyram are two commonly used broad-spectrum, low-toxic, and highly effective insecticides. They have different mechanisms and modes of action, and mixing can achieve a synergistic effect. However, emamectin benzoate is a poorly soluble pesticide in water, and nitenpyram is a hydrophilic pesticide. The difference in water solubility between the two limits the development of their mixed formulations. There are currently no reports on temperature-responsive emamectin benzoate-nitenpyram co-delivery liposomal nanopesticides. Summary of the invention

[0006] The purpose of the present invention is to provide a temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide and a preparation method thereof. The co-delivery of hydrophobic drugs and hydrophilic drugs is achieved in a nano drug delivery system, and the synergistic effect of the compounded agent is exerted; by adding a temperature "switch" (thermosensitive material), the nanopesticide has a temperature-responsive characteristic, and the pesticide release rate can be intelligently regulated according to the occurrence law of the pest population, thereby improving the targeting of the agent.

[0007] The temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide provided by the present invention is prepared from raw materials including the following components in parts by weight:

[0008]

[0009] Wherein, the temperature-sensitive material is a eutectic mixture of capric acid and stearic acid dibasic fatty acids,

[0010] The mass ratio of capric acid to stearic acid may be 3:1-10:1, specifically 9:1.

[0011] Natural fatty acids are commonly used temperature-responsive release materials, but a single fatty acid can lead to a burst release of the drug. To solve this problem, a eutectic mixture of two or even more fatty acids can be used to improve the drug loading capacity and obtain an ideal melting point.

[0012] The mass ratio of cholesterol to hydrogenated lecithin can be: 1:1-1:8, specifically 1:5;

[0013] The mass ratio of the capric acid-stearic acid dibasic fatty acid eutectic mixture to hydrogenated lecithin may be 1:2-1:6, specifically 1:4.

[0014] The mass ratio of emamectin benzoate to nitenpyram can be 2:1-1:8, specifically 2:3.

[0015] The temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide is prepared by a method comprising the following steps:

[0016] 1) heating and stirring a mixture of capric acid and stearic acid at 70-90° C., then ultrasonically dispersing at 40-50° C., and cooling naturally to obtain a capric acid-stearic acid dibasic fatty acid eutectic mixture;

[0017] 2) dissolving emamectin benzoate, hydrogenated lecithin, cholesterol and a eutectic mixture of capric acid-stearic acid dibasic fatty acid into an organic solvent, heating the resulting mixed solution to 40-60° C., and evaporating the solvent under vacuum to obtain a liposome film;

[0018] 3) dissolving nitenpyram in a PBS buffer solution to obtain an aqueous phase;

[0019] 4) mixing the aqueous phase with the liposome film obtained in 2), heating and hydrating to obtain a crude suspension of liposomes;

[0020] 5) subjecting the crude liposome suspension to ultrasonic crushing to obtain a fine liposome suspension;

[0021] 6) The obtained liposome fine suspension is dialyzed to obtain a temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide.

[0022] In step 1) of the above method, the mass ratio of capric acid to stearic acid may be: 3:1-10:1, specifically 9:1;

[0023] In step 2), the organic solvent may be chloroform; the concentration of hydrogenated lecithin in the mixed solution is 5-20 mg / mL;

[0024] In step 3), the concentration of nitenpyram in the aqueous phase may be 5-20 mg / mL;

[0025] In step 4), the heating and hydration conditions may be 45-55° C. for 30-60 min;

[0026] In step 5), the ultrasonic disruption treatment is achieved by a cell disruptor, and the parameters of the cell disruptor are set as follows: 200 W power, 5 s ultrasound, 2 s pause, and a total time of 3-10 min;

[0027] In step 6), the dialysis treatment is performed by placing the obtained liposome fine suspension into a dialysis bag and dialyzing it in 20-30° C. water for 2-6 hours to remove free pesticides and buffer salts to obtain the final nanopesticide.

[0028] The particle size of the obtained nano pesticide can be 1-100nm.

[0029] The application of the above-mentioned temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide in the control of diamondback moth also falls within the protection scope of the present invention.

[0030] In the application, emamectin benzoate and nitenpyram have synergistic effects, and the release of the drugs is temperature responsive.

[0031] The present invention achieves synergistic enhancement of pest control by co-loading pesticides with different mechanisms of action on pests. The hydrophobic pesticide emamectin benzoate and the hydrophilic pesticide nitenpyram in the obtained pesticide preparation are simultaneously encapsulated in liposomes, which can achieve co-delivery of hydrophobic drugs and hydrophilic drugs. The obtained drug-carrying system can regulate the pesticide release rate according to the occurrence law of pest populations.

[0032] Compared with conventional preparations, the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide provided by the present invention exhibits excellent leaf wettability and lower toxicity to zebrafish. Indoor biological activity experiments show that the control effect of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide provided by the present invention on diamondback moth increases with increasing temperature, which is consistent with the population growth trend of diamondback moth, and the emamectin benzoate and nitenpyram therein exhibit a synergistic effect in the control of diamondback moth. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the DSC curve of the dibasic fatty acid mixture prepared in Example 1 of the present invention.

[0034] Figure 2 This is an electron micrograph of the temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide prepared in Example 1 of the present invention.

[0035] Figure 3 This is the particle size distribution diagram of the temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide prepared in Example 1 of the present invention.

[0036] Figure 4 This is the release curve of emamectin benzoate in the temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide prepared in Example 1 of the present invention.

[0037] Figure 5 This is the release curve of nitenpyram in the temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide prepared in Example 1 of the present invention.

[0038] Figure 6 Contact angle and correlation analysis of the temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide prepared in Example 1 of the present invention on cabbage leaves.

[0039] Figure 7 The toxicity of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide prepared in Example 1 of the present invention to zebrafish. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0041] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0042] The temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide of the present invention is made of raw materials including the following components: hydrogenated lecithin, cholesterol, a dibasic fatty acid eutectic mixture, emamectin benzoate, nitenpyram;

[0043] The binary fatty acid eutectic mixture is a eutectic mixture of capric acid and stearic acid.

[0044] The optimal parameter combination for the temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide is: capric acid / stearic acid is 9:1, the ratio of hydrogenated lecithin to cholesterol is 5:1 (w / w), the ratio of binary fatty acid eutectic mixture to hydrogenated lecithin is 1:4 (w / w), the ratio of emamectin benzoate to hydrogenated lecithin is 1:3 (w / w), and the ratio of emamectin benzoate to nitenpyram is 2:3 (w / w).

[0045] The invention provides a method for preparing a binary fatty acid eutectic mixture, which comprises the following steps: preparing the binary fatty acid eutectic mixture by a heating-ultrasound method, stirring capric acid and stearic acid in a water bath at 80°C for 4 hours, then ultrasonically dispersing them at 50°C for 1 hour, and naturally cooling to obtain the binary fatty acid eutectic mixture.

[0046] The present invention also provides a method for preparing a temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide, the method comprising the following steps:

[0047] 1) fully dispersing hydrogenated lecithin, cholesterol, a dibasic fatty acid eutectic mixture and emamectin benzoate in chloroform, and evaporating the chloroform in the solution using a rotary evaporator to obtain a phospholipid film doped with the fatty acid eutectic mixture and emamectin benzoate;

[0048] 2) pouring the PBS solution containing nitenpyram into the phospholipid membrane and stirring in a water bath to fully hydrate the phospholipid membrane to obtain a crude liposome suspension;

[0049] 3) using a cell disruptor to ultrasonically disrupt the crude liposome solution to obtain a liposome fine suspension with uniform particle size;

[0050] 4) dialyzing the liposome fine suspension with uniform particle size using a dialysis bag to remove free pesticides and buffer salts to obtain a temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide.

[0051] The temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide prepared by the invention has excellent wettability on the cabbage leaf surface.

[0052] The present invention provides application of the temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide in preventing and controlling Plutella xylostella.

[0053] The present invention also provides a toxicity test of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide on a non-target organism, zebrafish.

[0054] Example 1. Preparation of temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide

[0055] The mixture of dibasic fatty acids of capric acid (DA) and stearic acid (SA) with different mass ratios (9:1, 7:1 and 3:1) was prepared by heating-ultrasound method (capric acid and stearic acid were stirred in a water bath at 80°C for 4h, then ultrasonically dispersed at 50°C for 1h and cooled naturally). The DSC curve of the obtained mixture was measured, as shown in Fig. Figure 1 As shown. The melting points of binary mixtures composed of capric acid (mp = 32 ° C) and stearic acid (mp = 57 ° C) are lower than those of the single components. Among them, the DSC curve of the mixture of capric acid: stearic acid with a ratio of 9:1 has a distinct and single endothermic peak, indicating that this binary mixture is a eutectic mixture with a melting point of 22 ° C, which is suitable as a temperature switch to respond to changes in the population of Plutella xylostella.

[0056] Preparation of binary fatty acid eutectic mixture: capric acid and stearic acid in a mass ratio of 9:1 were stirred in a water bath at 80° C. for 4 h, then ultrasonically dispersed at 50° C. for 1 h, and naturally cooled to obtain the binary fatty acid eutectic mixture.

[0057] Temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide (Co-EM-Lip) was prepared by a modified thin film dispersion-ultrasound method. Emamectin benzoate (0.067 g), hydrogenated lecithin (0.200 g), cholesterol (0.040 g) and dibasic fatty acid eutectic mixture (0.05 g) were dissolved in chloroform (15 mL). The mixture was heated to 55 ° C in a round-bottom flask, and the solvent was evaporated under vacuum using a rotary evaporator until a thin lipid film was formed. At 55 ° C, 20 mL of 5 mg / mL nitenpyram in PBS aqueous solution was hydrated for 30 minutes to obtain a coarse suspension. The coarse suspension was then sonicated using a cell disruptor for 3 minutes to obtain a fine suspension of liposomes. The parameters of the cell disruptor were: 200 W power, 5 s sonication, 2 s pause, and a total time of 3 minutes. Finally, the liposome fine suspension was placed in a dialysis bag and dialyzed in 25°C water for 4 h to remove free pesticides and buffer salts, thereby obtaining the final nanopesticide preparation.

[0058] Figure 2 The electron microscope image of the prepared temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide is shown in the form of a sphere or ellipsoid under TEM. The temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide of the present invention is not a single vesicle structure, but a multi-chamber structure composed of multiple small vesicles ( Figure 2 B).

[0059] Figure 3 This is the particle size distribution diagram of the prepared temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide; 150 particles were selected from TEM images taken in three independent experiments, and the average size of the temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide particles measured by Image Pro was 60.8nm.

[0060] Example 2

[0061] The temperature-responsive co-delivered liposomal nanopesticide Co-EM-Lip prepared in Example 1 was placed in a dialysis bag, and 100 mL of 20% (v / v) methanol aqueous solution was used as the release medium. The sample was released at 15°C, 25°C, and 35°C, and 1 mL of the release medium was collected at specified time intervals and replaced with an equal amount of fresh sustained-release medium. The concentrations of emamectin benzoate and nitenpyram in the collected samples were analyzed by high-performance liquid chromatography to calculate the cumulative release rate, and the release curves of emamectin benzoate and nitenpyram were plotted. Figure 4The release curve of emamectin benzoate in the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide prepared by the present invention; as can be seen from the figure, the release behavior of emamectin benzoate in the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide shows significant temperature response characteristics. After incubation at 15°C, 25°C and 35°C for 96h, the cumulative release of emamectin benzoate reached 54.0%, 71.3% and 91.7%, respectively. The results show that the release behavior of emamectin benzoate in the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide can be effectively regulated by temperature.

[0062] Figure 5 The release curve of nitenpyram in the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide prepared by the present invention; for the release of nitenpyram in the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide, 93.1% of nitenpyram was released within the first 5 hours at 35°C, which was 26.9% more than at 15°C, and this difference basically disappeared after 24 hours. The results show that the release behavior of nitenpyram in the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide can be effectively regulated by temperature.

[0063] Example 3

[0064] The contact angle of the temperature-responsive co-delivered liposomal nanopesticide and soluble granules (Co-SG, prepared by mixing emamectin benzoate water dispersible granules (5%, Shandong Bainong Sida Biotechnology Co., Ltd.) and nitenpyram water dispersible granules (20%, Shaanxi Huarong Kaiwei Biological Co., Ltd.) according to the content ratio of emamectin benzoate and nitenpyram in Co-EM-Lip to obtain Co-SG) was measured using a contact angle meter at room temperature. Fresh cabbage leaves in the greenhouse were selected, and the dust on the leaf surface was carefully cleaned without destroying the leaf structure. After natural drying in the air, some leaves were taken and smoothly adhered to a glass slide for standby use. 7 μL of the preparation dispersion was dropped on the surface of the cabbage leaves. The contact angle was measured by the five-point fitting method, and the average value of five repetitions was used.

[0065] The wetting of the target by the pesticide solution is an important process in the dose delivery system, and efficient wetting is an effective way to improve the effective utilization rate of pesticides. Figure 6The contact angle and correlation analysis of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide prepared by the present invention on cabbage leaves; the contact angle of water on cabbage leaves is 103.6°, the contact angle of the traditional soluble granules (Co-SG) is 73.9°, and the contact angle of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide (Co-EM-Lip) prepared in Example 1 reaches 54.2°. Through the significant difference test, it can be seen that the contact angle of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide on cabbage leaves is significantly different from that of the commercially available preparation, which indicates that the prepared temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide has better wettability.

[0066] Example 4

[0067] The control effect of Co-EM-Lip and Co-SG on Plutella xylostella was tested by leaf dipping method. Co-EM-Lip samples were dispersed in water and released at 15℃, 25℃ and 35℃. After 24 hours of release, the solution was diluted with pure water to obtain a series of dilutions with pesticide active ingredient concentrations of 10ppm, 5ppm, 2.5ppm, 1.25ppm, 0.625ppm and 0.3125ppm. Co-SG was directly diluted with water to the same concentration. Cabbage leaves were immersed in the above dispersion for 10 seconds, and pure water was used as a control. After air drying, the leaves were placed in a petri dish with filter paper. Then, 10 larvae of Plutella xylostella were introduced into each petri dish. The petri dishes were placed in a constant temperature room with 25±1℃ and good light. The mortality of Plutella xylostella was evaluated after 48 hours. If the larvae could not be induced to move when touched with a brush, they were considered dead. Three replicates were set for each group of experiments. The biological activity results of the two preparations against Plutella xylostella were obtained by calculation.

[0068] Table 1 shows the toxicity results of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide prepared in Example 1 of the present invention to Plutella xylostella; emamectin benzoate and nitenpyram are commonly used agents for the prevention and control of Plutella xylostella, so the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide (Co-EM-Lip) and the commercially available preparation (Co-SG) were compared with the target pest of Plutella xylostella. As shown in Table 1, the control effect of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide prepared in Example 1 of the present invention on Plutella xylostella increases with increasing temperature, and the insecticidal activity at 35°C is 4.4 times that at 15°C. Moreover, the insecticidal activity of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide at 35°C is 2.5 times that of the commercially available preparation. The enhancement of the biological activity of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide is mainly attributed to the rapid release characteristics of the active ingredients of the pesticide at high temperatures. The diamondback moth causes the most serious damage to crops at 25-30℃. The release characteristics of the active ingredients in the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide at different temperatures are consistent with the population growth trend of the diamondback moth, which is conducive to the precise prevention and control of pests.

[0069] In addition, in order to verify the synergistic effect of emamectin benzoate and nitenpyram in the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide of the co-delivery system, the co-toxicity coefficient of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide was calculated. As shown in Table 1, at 35°C, the co-toxicity coefficient of the co-delivery system was 248.16, showing a significant synergistic effect. At 25°C, the two drugs showed an additive effect, and at 15°C, they showed an antagonistic effect. High temperature environment activates the temperature "switch" in the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide, thereby enhancing the synergistic effect of emamectin benzoate and nitenpyram. This temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide can achieve efficient and intelligent prevention and control of pests, significantly improve the utilization rate of pesticides, reduce the amount used, and delay pesticide resistance.

[0070] Table 1 The biological activity results of temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticides and soluble granules against Plutella xylostella

[0071]

[0072] Note: EB-EM-Lip refers to liposome nanopesticide loaded with emamectin benzoate alone, and Nit-EM-Lip refers to liposome nanopesticide loaded with nitenpyram alone. The preparation method thereof is the same as that in Example 1.

[0073] Example 5

[0074] Using zebrafish as a model organism, the toxicity of Co-EM-Lip and Co-SG to non-target organisms was tested. Co-EM-Lip and Co-SG were diluted with water to obtain sample solutions with different active ingredient concentrations. Adult zebrafish (n=12) were randomly selected and transferred to 1L of sample solution at room temperature. During the experiment, the solution was replaced every 24 hours to maintain the concentration of the active ingredient and water quality. The poisoning symptoms and mortality of the tested zebrafish were observed within 96 hours, and the 96h LC50 was calculated.

[0075] Figure 7 The toxicity of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide prepared in Example 1 of the present invention to zebrafish; after application, the pesticide will enter the river with external factors such as rainwater erosion, thereby causing a series of environmental and ecological problems. Figure 7 The survival rate of zebrafish decreased with the increase of drug concentration and time in the experimental groups of temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide (Co-EM-Lip) and commercial preparation (Co-SG). The LC of zebrafish at 96h was 50 The toxicity of the commercially available preparation was 2.1 times that of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide. This indicates that the nanopesticide effectively reduced the toxicity of emamectin benzoate and nitenpyram to zebrafish.

[0076] The present invention has been described in detail above. For those skilled in the art, without departing from the purpose and scope of the present invention, and without the need to carry out unnecessary experimental conditions, the present invention can be implemented in a wide range under equivalent parameters, concentrations and conditions. Although the present invention provides specific embodiments, it should be understood that the present invention can be further improved. In a word, according to the principles of the present invention, the application is intended to include any changes, uses or improvements to the present invention, including departure from the disclosed scope in the application, and changes made with conventional techniques known in the art.

Claims

1. A temperature-responsive emamectin benzoate-nitenpyram co-delivery liposome nanopesticide, which is made of the following raw materials in parts by weight: in, The temperature-sensitive material is a eutectic mixture of capric acid and stearic acid dibasic fatty acids.

2. The nanopesticide according to claim 1, characterized in that: The mass ratio of capric acid to stearic acid is 3:1-10:1, preferably 9:

1.

3. A method for preparing the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide according to claim 1 or 2, comprising the following steps: 1) heating and stirring a mixture of capric acid and stearic acid at 70-90° C., then ultrasonically dispersing at 40-50° C., and cooling naturally to obtain a capric acid-stearic acid dibasic fatty acid eutectic mixture; 2) dissolving emamectin benzoate, hydrogenated lecithin, cholesterol and a eutectic mixture of capric acid-stearic acid dibasic fatty acid into an organic solvent, heating the resulting mixed solution to 40-60° C., and evaporating the solvent under vacuum to obtain a liposome film; 3) dissolving nitenpyram in a PBS buffer solution to obtain an aqueous phase; 4) mixing the aqueous phase with the liposome film obtained in 2), heating and hydrating to obtain a crude suspension of liposomes; 5) subjecting the crude liposome suspension to ultrasonic crushing to obtain a fine liposome suspension; 6) The obtained liposome fine suspension is dialyzed to obtain a temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide.

4. The method according to claim 3, characterized in that: In step 1), the mass ratio of capric acid to stearic acid is 3:1-10:1, preferably 9:

1.

5. The method according to claim 3 or 4, characterized in that: In step 2), the organic solvent may be chloroform; and the concentration of hydrogenated lecithin in the mixed solution is 5-20 mg / mL.

6. The method according to any one of claims 3 to 5, characterized in that: In step 3), the concentration of nitenpyram in the aqueous phase is 5-20 mg / mL; in step 4), the heating hydration condition is hydration at 45-55° C. for 30-60 min.

7. The method according to any one of claims 3 to 6, characterized in that: In step 5), the ultrasonic disruption treatment is achieved by a cell disruptor, and the parameters of the cell disruptor are set as: 200 W power, 5 s ultrasound, pause 2 s, and a total time of 3-10 min.

8. The method according to any one of claims 3 to 7, characterized in that: In step 6), the dialysis treatment is performed by placing the obtained liposome fine suspension into a dialysis bag and dialyzing it in 20-30° C. water for 2-6 hours to remove free pesticides and buffer salts to obtain the final nanopesticide.

9. The method according to any one of claims 3 to 8, characterized in that: The particle size of the obtained nano pesticide is 1-100nm.

10. Use of the temperature-responsive emamectin benzoate-nitenpyram co-delivered liposome nanopesticide according to claim 1 or 2 in the control of Plutella xylostella.

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