阅读说明：本技术 一种阿维菌素纳米缓释体及其制备方法和应用 (Avermectin nano slow-release body and preparation method and application thereof ) 是由 李振亚 苏丽娟 尹新明 宋南 安世恒 魏纪珍 于 2020-07-21 设计创作，主要内容包括：本发明属于环境友好型纳米农药领域,特别是指一种阿维菌素纳米缓释体及其制备方法和应用。通过制备纳米几丁质和纳米阿维菌素,经过共价结合作用制备出负载纳米阿维菌素的载药颗粒。负载纳米阿维菌素的载药颗粒,具有较大的比表面积及其他纳米特性,具有纳米尺寸优势,能够克服叶面沉降阻力,减少有机溶剂的使用,提高对于靶标部位的覆盖率且粘附性好,显著增加纳米阿维菌素与生物膜的接触面积,有助于提高持效期和利用度。本发明对于提高阿维菌素农药的利用率,提高阿维菌素的杀虫效果,降低阿维菌素农药的使用量、残留及污染具有重要的应用价值,对新型环境友好型绿色农药及纳米农药的开发有重要参考意义。(The invention belongs to the field of environment-friendly nano pesticides, and particularly relates to an avermectin nano slow-release carrier and a preparation method and application thereof. The drug-loaded particles loaded with nano avermectin are prepared by preparing nano chitin and nano avermectin and performing covalent binding. The drug-loaded particles loaded with the nano abamectin have large specific surface area and other nano characteristics, have the advantage of nano size, can overcome the leaf surface settlement resistance, reduce the use of organic solvents, improve the coverage rate to target parts, have good adhesion, remarkably increase the contact area of the nano abamectin and a biological membrane, and contribute to improving the lasting period and the availability. The invention has important application value for improving the utilization rate of the abamectin pesticide, improving the insecticidal effect of the abamectin and reducing the use amount, residue and pollution of the abamectin pesticide, and has important reference significance for the development of novel environment-friendly green pesticide and nano pesticide.)

1. A preparation method of an abamectin nanometer slow-release body is characterized by comprising the following steps:

(1) adding chitin powder into concentrated acid, heating in water bath for acidolysis, centrifuging the mixed solution to obtain precipitate, and performing ultrasonic treatment on the precipitate to obtain nanometer chitin as carrier;

(2) under the condition of keeping out of the sun, adding acetone into the abamectin original drug for assisting dissolution, dispersing the abamectin original drug in water, and carrying out ultrasonic crushing treatment on the dispersion liquid to obtain nano abamectin;

(3) and (2) mixing the nano abamectin obtained in the step (2) with the nano chitin obtained in the step (1) under a dark condition, carrying out shaking table oscillation reaction under a heating condition to obtain an aqueous dispersion of the nano abamectin and the nano chitin sustained-release body, and carrying out vacuum freeze drying to obtain the abamectin nano sustained-release body.

2. The preparation method of the avermectin nanometer sustained release carrier according to claim 1, which is characterized in that: the concentrated acid in the step (1) is a hydrochloric acid solution with the concentration of 2 mol/L.

3. The preparation method of the avermectin nanometer sustained release carrier according to claim 2, which is characterized in that: in the step (1), the temperature of the water bath is 40-70 ℃, the acidolysis time is 1-3 h, the ultrasonic treatment condition is that the power is 100-.

4. The preparation method of the avermectin nanometer sustained release carrier according to claim 1, which is characterized in that: in the step (2), 2-20 mL of acetone is added into each g of abamectin technical product.

5. The preparation method of the avermectin nanometer sustained release carrier according to claim 4, which is characterized in that: in the step (2), every 100mL of the acetone solution of the abamectin technical material has the corresponding ultrasonic power of 50-300W and the ultrasonic time of 5-20 min.

6. The preparation method of the avermectin nanometer sustained release carrier according to claim 1, which is characterized in that: in the step (3), the mass ratio of the mixed nano chitin to the nano abamectin is (1-10) to 1.

7. The preparation method of the avermectin nanometer sustained release carrier according to claim 6, which is characterized in that: in the step (3), the shaking table oscillation reaction is carried out at the temperature of 20-40 ℃ for 4-12 h.

8. The avermectin nanometer slow release preparation prepared by the method of any one of claims 1 to 7, which is characterized in that: the effective grain diameter of the avermectin nanometer slow release body is controllable within the range of 100-600 nm.

9. The use of avermectin nano-sustained release carrier of claim 8 in the preparation of agricultural pest control agents.

Technical Field

The invention belongs to the field of environment-friendly nano pesticides, and particularly relates to an avermectin nano slow-release carrier and a preparation method and application thereof.

Background

The pesticide is a basic production material of agriculture, can solve the basic survival problem of human beings, and provides guarantee for maintaining social stability. The traditional pesticide formulation has the defects of high organic solvent content, dust drift, poor dispersibility and the like, and causes low utilization rate and environmental pollution. According to statistics, the pesticide utilization rate is 36.6 percent after the implementation of 'zero increase action of fertilizer and pesticide usage amount' in China. In recent years, the development of pesticide slow control theory and technology opens up a new direction for solving the problem, aims to reduce the demand of crops on pesticides, gradually complete more effective and safer pesticide design, slow down and control the release of pesticides, and select a proper and timely administration way to realize accurate regulation and control of target pests.

The abamectin is a microbial fermentation product of streptomyces griseus, contains various insecticidal components, and is finally purified by a common ultrasonic centrifugation method in industrial production. The first characteristic of abamectin is high efficiency and can kill several kinds of pests, and the second characteristic is that it is different from other pesticide in medicinal property, and is not easy to produce resistance to pesticide(ii) a The third characteristic is safety, because the agent sprayed on the surface of the plant can be decomposed quickly, the plant is safe to natural enemies and has less pollution to the environment. But the disadvantages of the abamectin in the practical agricultural application are very obvious, firstly, the insecticidal speed is low, the target pests have slow action after eating and refuse to eat, and die after 2 to 4 days; secondly, the toxicity of the raw medicine is high, and the toxicity level of the medicine is reduced by low content of active ingredients of various medicines, but the use still needs to pay attention to safety; thirdly, the production cost is higher. In recent years, a series of mixed insecticides containing abamectin are developed, such as mixed insecticides of various pyrethrins and chlorpyrifos, and the like, which can accelerate the death speed of pests; increase contact killing or other action modes, and limit the efficacy and the effective period of the abamectin due to instability of the abamectin. The improvement of the abamectin is beneficial to agricultural development of the abamectin, prolongs the pesticide effect period, meets the development and the development of high-toxicity pesticide substitutes, and has important theoretical significance and practical significance. An article on the basis of the construction of an avermectin nano drug-carrying system and the slow-release behavior research discloses avermectin and hollow nano SiO₂The construction of a drug-carrying system, the drug-carrying system mainly adopts the adsorption effect of the silicon dioxide nano microspheres, and the slow release mechanism does not relate to chemical reaction.

With the development of nano materials, the chitin nano particles can realize controlled, sustained and targeted drug release, and meanwhile, the materials are biodegradable, biocompatible, safe and nontoxic to the environment and organisms, can be used as drug/pesticide delivery carriers, and although the materials are researched more in the medical and pharmaceutical fields and are widely applied, the materials are rarely applied in agriculture. In addition, abamectin is sensitive to environments such as light, pH, temperature and the like, is easy to degrade and loses efficacy, only a small amount of effective components can reach a target part in actual agricultural production, and the utilization rate is low. The pesticide particles are combined with chitin to prepare the nano pesticide, so that the degradation and loss of the active ingredients caused by the change of light, heat and acid-base environments can be reduced, the abamectin and the nano chitin can be compounded by applying the theory and the technology to prepare the nano pesticide with biocompatibility and biodegradability, the utilization efficiency is high, the environmental pollution is small, and the current use situation of the abamectin is improved.

At present, although the nano chitin is researched in the aspect of crop pest control, the drug loading and slow release performance of the nano chitin on crop pest control is not reported. Through search, the applicant has no research on the loading of the nano chitin pesticide and the loading performance at present. Meanwhile, the preparation process of the nanoparticles in the above patent is complex, part of the preparation reactions are violent, and part of the preparation reactions use organic solvents, which inevitably increases the preparation cost. Therefore, the pesticide loading performance of the nanochitin is explored while the preparation process is simplified, and the method has important significance for effective and safe pesticide application and improvement of the pesticide utilization rate.

Disclosure of Invention

The invention provides an avermectin nanometer slow release body and a preparation method and application thereof, the avermectin is compounded with nanometer chitin into a nanometer conjugate in a covalent combination mode, and the avermectin nanometer slow release body has the characteristics of large drug loading rate, obvious slow release effect, better thermal stability and light stability and better killing effect on lepidoptera pests, overcomes the defects of limitation of avermectin preparation conditions and easy photolysis, is mainly applied to preventing and treating crop diseases and insect pests, and has important technical reference for prolonging the pesticide effect period of the avermectin and improving the bioavailability.

The technical scheme of the invention is realized as follows:

a preparation method of avermectin nanometer sustained release carrier comprises the following steps:

(1) adding chitin powder into concentrated acid, heating in water bath for acidolysis, centrifuging the mixed solution to obtain precipitate, and performing ultrasonic treatment on the precipitate to obtain nanometer chitin as carrier;

(2) under the condition of keeping out of the sun, adding acetone into the abamectin original drug for assisting dissolution, dispersing the abamectin original drug in water, and carrying out ultrasonic crushing treatment on the dispersion liquid to obtain nano abamectin;

(3) and (2) mixing the nano abamectin obtained in the step (2) with the nano chitin obtained in the step (1) under a dark condition, carrying out shaking table oscillation reaction under a heating condition to obtain an aqueous dispersion of the nano abamectin and the nano chitin sustained-release body, and carrying out vacuum freeze drying to obtain the abamectin nano sustained-release body.

The concentrated acid in the step (1) is a hydrochloric acid solution with the concentration of 2 mol/L.

In the step (1), the temperature of the water bath is 40-70 ℃, the acidolysis time is 1-3 h, the ultrasonic treatment condition is that the power is 100-.

And (3) adding 2-20 mL of acetone into each gram of abamectin technical in the step (2).

In the step (2), every 100mL of the acetone solution of the abamectin technical material has the corresponding ultrasonic power of 50-300W and the ultrasonic time of 5-20 min.

In the step (3), the mass ratio of the mixed nano chitin to the nano abamectin is (1-10) to 1.

In the step (3), the shaking table oscillation reaction is carried out at the temperature of 20-40 ℃ for 4-12 h.

The effective particle size of the avermectin nano sustained release preparation prepared by the method is controllable within the range of 100-600 nm.

The avermectin nanometer slow-release body is applied to preparing agricultural pest control reagents.

The invention has the following beneficial effects:

1. the nano slow-release body prepared by the invention has a slow-release effect, improves the light and heat stability and the dispersion performance of the abamectin, can effectively improve the utilization rate of the abamectin, delays the release rate of the abamectin, reduces the application amount and further reduces the pollution and the residual condition of pesticides to soil and environment.

2. The nano sustained release body prepared by the invention can regulate and control the particle size of the sustained release body by changing the mass ratio of the chitosan and the abamectin so as to regulate and control the drug-loading rate of the abamectin. The drug-loaded particles loaded with the nano abamectin have the advantages of uniform particle size, good dispersibility, larger specific surface area and other nano characteristics, nano-size advantage, capability of overcoming leaf surface settlement resistance, reduction of use of organic solvents, improvement of coverage rate to target parts, good adhesion, remarkable increase of contact area of the nano abamectin and a biological membrane, and contribution to improvement of duration and availability. Meanwhile, the adopted carrier is derived from chitin, is safe, nontoxic, naturally degradable and low in cost. The method has important application values for improving the utilization rate of the abamectin pesticide, improving the insecticidal effect of the abamectin and reducing the use amount, residue and pollution of the abamectin pesticide.

3. The method has the advantages of mild reaction conditions, simple steps, low requirements on instruments and equipment, simple process and suitability for mass preparation and production. The carrier is derived from chitin, is safe, nontoxic, degradable and low in cost. The method has important application values for improving the utilization rate of the abamectin pesticide, improving the insecticidal effect of the abamectin and reducing the use amount, residue and pollution of the abamectin pesticide.

4. The invention avoids a plurality of organic solvents and overcomes the problem of difficult solubility of a plurality of pesticides, and also provides a new method for the development of novel green and safe pesticides.

5. The nano chitin whisker prepared by the invention is not only suitable for abamectin, but also suitable for other pesticides, and can be applied to crop pest control or comprehensive control.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a transmission electron microscope image of the nanochitin particles prepared in example 4 of the present invention.

FIG. 2 is a transmission electron microscope image of the nano avermectin prepared in example 4 of the present invention.

FIG. 3 is a transmission electron microscope image of the avermectin nano-sustained release preparation prepared in example 4 of the present invention.

FIG. 4 shows the particle size and the degree of dispersion of the avermectin nano-sustained release preparation prepared in example 4 of the present invention after standing for 50 days at 6 ℃ and 25 ℃.

FIG. 5 is an electronic image of an aqueous dispersion of avermectin nano-sustained release, nano-avermectin and nano-chitin prepared in examples 1 to 5 of the present invention after standing for 60 days at room temperature, wherein A is a nano-avermectin aqueous dispersion control, B is an aqueous suspension of nano-sustained release of example 1 having a mass ratio of nano-chitin to nano-avermectin of 1:1, C is an aqueous suspension of nano-sustained release of example 2 having a mass ratio of nano-chitin to nano-avermectin of 2:1, D is an aqueous suspension of nano-sustained release of example 3 having a mass ratio of nano-chitin to nano-avermectin of 4:1, E is an aqueous suspension of nano-sustained release of example 4 having a mass ratio of nano-chitin to nano-avermectin of 6:1, F is an aqueous suspension of nano-sustained release of example 5 having a mass ratio of nano-chitin to nano-avermectin of 8:1, g is a nanochitin aqueous suspension control, wherein the concentration of A to G is 5.0 mg/mL.

Fig. 6 is a release curve of the avermectin nano-sustained release preparation prepared in example 4 in a water phase with a pH of 7.0.

Fig. 7 shows the sustained release rates of the nano avermectin sustained release formulation prepared in example 4 in PBS buffer solutions with pH values of 5.0, 6.0, 7.0, 8.0, and 9.0, respectively.

Fig. 8 is an infrared spectrum of the avermectin nano sustained release preparation prepared in example 4, and the original avermectin, chitin powder and nano chitin.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.