CN105010362B - One kind application lignin-base wall material prepares avermectin microcapsule powder and its method - Google Patents

Abstract

The invention discloses a method for preparing abamectin microcapsule powder by using a lignin-based wall material. In the method, the purified amino lignosulfonate wall material and an emulsifier are dissolved in water to prepare an aqueous solution to obtain an aqueous phase; the original drug of avermectin is dissolved in an organic solvent to obtain an organic phase; The organic phase is evenly added to the water phase, and then sheared; then the pH value of the dispersion is adjusted to carry out complex coagulation reaction; the temperature is lowered, a cross-linking agent is added to carry out the cross-linking reaction, centrifuged, filtered and dried to obtain microcapsule powder; The preparation process of the avermectin microcapsule powder is simple, the wall material is green and degradable, and can prevent the photolysis of the original drug. Controlling the release is achieved within a certain pH range.

Description

A kind of application lignin base wall material prepares abamectin microcapsule powder and method thereof

technical field

The invention relates to an abamectin microcapsule powder, in particular to a method for preparing abamectin microcapsule powder by using a lignin-based wall material.

Background technique

my country is a big country in the production and consumption of pesticides. In 2013, the output and self-use of pesticide preparations in my country were about 1.6 million tons and 1 million tons respectively. According to statistics, the amount of pesticides used per unit of arable land in my country is 2.5 times the world average. The use of a large amount of pesticides has kept production, but it has also caused serious pollution to the environment. The traditional pesticide preparations based on powder, wettable powder and emulsifiable concentrate have problems such as low utilization rate of pesticides and easy harm to the environment and mammals. Therefore, modern pesticide preparations are gradually becoming more efficient, low-toxic, low-residue, economical, safe and convenient. development in harmony with the environment.

In recent years, pesticide microcapsule dosage forms have gradually attracted people's attention due to their advantages of environmental protection, low toxicity, slow release, high efficiency and stability. Microcapsule technology refers to the technology of wrapping the core material in the wall material to form particles with a size between 1 and 100 μm. Most of its wall materials are polymer materials. Due to the advantages of wide sources of natural polymers, easy availability of raw materials, non-toxic and degradable, easy processing, and low cost, it has become a research hotspot for pesticide carrier materials. Among them, gum arabic, gelatin, seaweed, etc. The research and application of natural polymer materials such as sodium bicarbonate and chitosan are the most widely used.

As lignin is also a natural renewable polymer compound, there are few studies on its use as a microcapsule wall material. Mariarosaria [Mariarosaria Tortora, Francesca Cavalieri, et al. UltrasoundDriven Assembly of Lignin into Microcapsules for Storage and Delivery of Hydrophobic Molecules. Biomacromolecules, 2014, 15:1634‐1643.] Dissolve coumarin in chloroform and mix it with olive oil, then The mixed liquid is added into the lignin aqueous solution, after ultrasonic emulsification, centrifuged to obtain a uniform spherical microcapsule product. At the same time, the release experiment of the microcapsules was carried out, and it was found that the microcapsules could remain stable for a long time in aqueous solution without obvious release.

Zhou Bin [Zhou Bin. Layer-by-layer self-assembly preparation of drug-loaded chitosan/sodium lignosulfonate microcapsules and its drug release behavior. Beijing: Beijing University of Chemical Technology, 2008.] Preparation of chitosan/lignin by layer-by-layer self-assembly Sodium sulfonate microcapsules. First disperse abamectin in an aqueous solution of sodium dodecylbenzenesulfonate to obtain abamectin with a charged adsorption layer, and then soak abamectin in an aqueous solution of chitosan and sodium lignosulfonate in sequence Layer-by-layer self-assembly was carried out to obtain microcapsules. The drug release performance of microcapsules was studied, and it was found that the drug release rate decreased significantly with the increase of the number of self-assembled layers. In addition, with the increase of the salt concentration in the system, the wall thickness of the microcapsules increases, and the release rate also decreases significantly. It is a traditional method to prepare microcapsules by self-assembly of chitosan layer by layer. Although the prepared microcapsules have a certain slow-release effect, the molecular weight of chitosan is too large, so it is difficult to operate during the preparation process. The particle size is difficult to uniformly control, and the loading rate is relatively low; and a large amount of chitosan is used, which is costly and complicated, and has little practical application value.

Fu Weijin[Fu Weijin, Zhang Shuting et al. Preparation and sustained release performance of lignin phenolic-based drug-loaded microspheres. Polymer Materials Science and Engineering, 2012,28(10):117‐120.] et al. Mix and react with abamectin, formaldehyde, phenol and cetyltrimethylammonium bromide to obtain lignin phenolic prepolymer, then add the prepolymer to peanut oil to continue the reaction, separate and dry to obtain lignin phenolic base microcapsules. The study on the slow-release behavior of microcapsules found that the slow-release effect was the best when the added amount of lignin was 50%. In this method, lignin is mixed with abamectin, formaldehyde, phenol and cetyltrimethylammonium bromide in a pot of porridge. The reaction conditions in the preparation process are harsh, and the macrolide structure of abamectin is easily damaged. The effective content of the original drug is reduced; and the prepared microcapsules have a larger particle size, which cannot meet the requirements of microcapsule drug efficacy.

Chinese invention patent application CN102349509A discloses a method for preparing lignin urea-formaldehyde-based pesticide microcapsules. Firstly, urea, formaldehyde and lignin are mixed to obtain a prepolymer, and then the prepolymer is added to the alginate containing Span‐85 and chlorobenzene. The emulsion is obtained from the vermectin solution, and finally the emulsion is added to the oxalic acid aqueous solution, and the microcapsules are obtained after filtering and drying. The particle size of the obtained microcapsules is about 20 μm, the drug loading and loading rate are respectively between 15-35% and 60-80%, and the sustained release time is about 120h. In this method, the prepolymer is emulsified with abamectin, solvent, and emulsifier, and then acidified and condensed. The whole process is completely similar to the preparation method of urea-formaldehyde resin microcapsules. Adding lignin raw materials on the basis of the method; this method requires a large amount of wall materials, and the loading rate is very low, and the particles are large, which is a very inefficient embedding method, which is basically impossible to realize in industry.

At present, there are few reports on the preparation of microcapsules with lignin as the main wall material, and the low loading rate of the original drug, high decomposition rate of the original drug during the embedding process, large particle size of the microcapsules, and complicated preparation process are common problems. However, there are no reports about the use of pH-responsive lignin derivatives as wall materials to prepare microcapsules.

Contents of the invention

The object of the present invention is to prepare abamectin microcapsule powder and method thereof by using sodium amino lignosulfonate with pH responsiveness as wall material. The product is environmentally friendly, non-toxic, low in price and resistant to sunlight photolysis.

In the present invention, an amino-based sodium lignosulfonate is used as the wall material, and the abamectin original drug and the lignin-based wall material are respectively dissolved in a solvent, and then formed into capsules by a complex coacervation method, and finally a cross-linking agent is added to the aqueous solution A cross-linking reaction is carried out on the lignin-based wall material to prepare an abamectin microcapsule suspension, which is then dried to obtain microcapsule powder. Wherein the main wall material that microcapsule adopts is sodium amino lignosulfonate, and core material is abamectin, by regulating the pH of aqueous solution of wall material aqueous solution of sodium amino lignosulfonate, make sodium amino lignosulfonate molecule Co-aggregate with abamectin nanoparticles to prepare sodium amino lignosulfonate/abamectin composite microspheres, so as to realize the embedding of avermectin, and then chemically cross-link the amino group The sodium lignosulfonate wall material undergoes a cross-linking reaction to obtain chemically cross-linked composite microspheres, and then the avermectin microcapsule powder can be obtained through drying to remove moisture.

The present invention uses the pH-responsive sodium lignosulfonate amino group containing both anion and cation functional groups of the sulfonic acid group as the wall material, and changes the charge distribution of the molecule by adjusting the pH of the sodium lignosulfonate aqueous solution, thereby The lignin-based microcapsules can be prepared by regulating its molecular configuration and aggregation degree to achieve the effect of encapsulating pesticides.

The purpose of the present invention is to realize by following technical scheme:

A method for preparing abamectin microcapsule powder using lignin-based wall material, comprising the following steps:

1) In terms of parts by mass, 100 parts of purified sodium lignosulfonate wall material and 5-20 parts of emulsifier are dissolved in 200-500 parts of water to prepare an aqueous solution to obtain an aqueous phase;

2) dissolving the original drug of avermectin in an organic solvent to obtain an organic phase;

3) Evenly add the organic phase to the water phase under the condition of rotation, and then shear for 10-20 minutes; then adjust the pH value of the dispersion to 6-8, and carry out complex coagulation reaction at 20-40°C for 30-60 minutes ; Cool down to 0-20°C, add 1-10 parts of cross-linking agent to carry out cross-linking reaction for 1-2 hours, and prepare abamectin microcapsule suspension;

4) centrifuging the prepared Abamectin microcapsule suspension, removing water and solvent, then freeze-drying the residual solid to obtain Abamectin microcapsule powder;

The amino sodium lignosulfonate wall material is prepared by the following method: dissolving sodium lignosulfonate in water to prepare an aqueous solution of sodium lignosulfonate, adjusting the pH value of the solution to 10.0-13.0, and activating it at 50-70°C 0.5 ~ 1.0h; add amination modifier, then drop aldehyde reagents, after the dropwise addition, react at 70 ~ 90 ° C for 2 ~ 4 hours to obtain amino sodium lignosulfonate solution; the obtained amino lignosulfonate solution The sodium sulfonate solution is extracted with an alcohol reagent, the residual solid after extraction is washed with petroleum ether, and the residue after washing is freeze-dried to obtain a purified powdery sodium aminolignin sulfonate wall material ; The amination reagent is diethylamine, propylenediamine, triethylamine, diethylenetriamine or triethylenetetramine; the aldehyde reagent is formaldehyde, acetaldehyde, propionaldehyde, glyoxal or glutaraldehyde ; The alcohol reagent is one or more of methanol, ethanol, propanol, isopropanol and butanol.

The emulsifier is one or more of sodium lauryl sulfate, sodium dodecylbenzenesulfonate, polyethylene glycol 1000, cetyltrimethylammonium bromide and Tween-80;

The organic solvent is one or more of dimethyl sulfoxide, pyrrolidone, methylene chloride, methanol, ethanol;

The crosslinking agent is one of sodium tripolyphosphate, formaldehyde, glyoxal, glutaraldehyde and epichlorohydrin.

In order to better realize the purpose of the present invention, preferably, in terms of parts by mass, the organic phase is obtained by dissolving 20-200 parts of the original drug of abamectin in 200-500 parts of an organic solvent.

Preferably, the rotational speed of the rotation condition is 500-1500 rpm; the time for uniformly adding the organic phase to the water phase is 20-40 minutes.

Preferably, in parts by mass, the aqueous solution of sodium lignosulfonate is prepared by dissolving 100 parts of sodium lignosulfonate in 150-400 parts of water.

Preferably, the amination modifier is added in an amount of 20-200 parts by mass.

Preferably, in terms of parts by mass, the added amount of the aldehyde reagent is 20-200 parts.

Preferably, in terms of parts by mass, the dropping is adding 20-200 parts of aldehyde reagents within 0.5-1.0 h.

Preferably, in terms of parts by mass, the extraction of the obtained sodium amino lignosulfonate solution with an alcohol reagent is to use 100 parts of the sodium amino lignosulfonate solution obtained by the reaction with 100 to 300 parts of alcohol Reagents for extraction.

A kind of avermectin microcapsule powder prepared by lignin-based wall material is prepared by the above-mentioned method.

The purity of the original drug of avermectin is 92%; the amino sodium lignosulfonate wall material of the present invention is obtained by modifying sodium lignosulfonate with polyamines, and the purity is >95%; NaOH, KOH are preferably used Or H ₂ SO ₄ , HCl to adjust the pH value of the solution or the pH value of the dispersion.

In the present invention, except sodium aminolignin sulfonate and abamectin original drug, all are calculated according to pure content.

Compared with similar products, the raw materials of wall materials come from a wide range of sources and several are cheap; the raw materials of wall materials are natural polymers, which can be naturally degraded into fertilizers; the molecules of wall materials contain a large number of polyphenol structures, which can significantly absorb free radicals in materials, and can Prevent the original drug from being photolyzed by ultraviolet light; the prepared microcapsule powder has a relatively high drug loading and entrapment rate, and the sustained release effect is remarkable; because the wall material used has pH responsiveness, the prepared microcapsule powder can The control of the release can be realized in the pH range.

Compared with the prior art, the present invention has the following advantages and effects:

1. The reaction involved in the present invention is carried out at normal pressure and low temperature, the operation is simple, easy to control, and the product is environmentally friendly and non-toxic;

2. The preparation method of the abamectin microcapsules involved in the present invention, the materials used are environmentally friendly and degradable, the reagents have no toxic effect on animals and plants, and the price is low, which has certain advantages compared with the existing microcapsule products;

3. The present invention uses lignin as the main wall material to prepare abamectin microcapsules. Since the lignin wall material molecules contain a large amount of hindered phenolic structures, it can effectively solve the defect that the original drug of abamectin is not resistant to sunlight photolysis ;

4. The microcapsules prepared by the present invention have higher drug loading capacity and entrapment rate, and the sustained release effect is obvious;

5. The microcapsules prepared by the present invention have pH responsiveness, can realize pesticide embedding and controlled release in a certain pH range, and have a wide application range.

Description of drawings

Figure 1 is the cumulative release curves of the microcapsules prepared in Example 1 in release media with different pHs.

Fig. 2 is the comparison of release rate between the microcapsules prepared in Example 1 and commercial microcapsules.

Fig. 3 is a microscope image of the microcapsules prepared in Example 1, 96×72 μm.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and examples, but the examples are not intended to limit the scope of protection claimed by the present invention.

Example 1

Dissolve 100g of sodium lignosulfonate in 400g of water, adjust the pH to 12, activate in a water bath at 50°C for 0.5h, add 50g of diethylenetriamine, slowly add 50g of formaldehyde dropwise, complete the dropwise addition within 0.5h, and raise the temperature to 70°C °C, the reaction was continued for 4 h to obtain a sodium amino lignosulfonate solution. The obtained sodium amino lignosulfonate solution is extracted with ethanol, and the residual solid after extraction is washed with petroleum ether and then freeze-dried to obtain purified powdery sodium amino lignosulfonate.

Dissolve 100g of purified amino lignosulfonate sodium wall material, 8g of sodium lauryl sulfate and 5g of polyethylene glycol 1000 in 200g of water to prepare an aqueous solution to obtain the aqueous phase; dissolve 100g of abamectin in 500g of dichloromethane to obtain the organic phase. Add the organic phase to the water phase evenly within 30 minutes at 1000rpm, and then shear for 15 minutes; then adjust the pH of the dispersion to 8 with 10% hydrochloric acid solution, and carry out complex coagulation reaction at 20°C for 60 minutes . Cool down to 5° C., add 2 g of glutaraldehyde to carry out cross-linking reaction, and keep the reaction for 1 hour to prepare abamectin microcapsule suspension. The prepared avermectin microcapsule suspension is centrifuged, water and solvent are removed, and then the residual solid is freeze-dried to obtain the avermectin microcapsule powder.

Example 2

Dissolve 100g of sodium lignosulfonate in 150g of water, adjust the pH to 10, activate in a water bath at 60°C for 1.0h, add 20g of triethylamine, slowly add 20g of acetaldehyde dropwise, complete the dropwise addition within 1h, and raise the temperature to 80°C , Continue to react for 2h to obtain sodium amino lignosulfonate solution. The obtained sodium amino lignosulfonate solution is extracted with ethanol, and the residual solid after extraction is washed with petroleum ether and then freeze-dried to obtain purified powdery sodium amino lignosulfonate.

100g of purified amino lignosulfonate wall material and 5g of Tween-80 were dissolved in 350g of water to prepare an aqueous solution to obtain an aqueous phase; 20g of abamectin was dissolved in 200g of dimethyl sulfoxide to obtain an organic phase . Add the organic phase to the water phase evenly within 30 minutes at 800rpm, and then shear for 10 minutes; then adjust the pH of the dispersion to 6.5 with HCl solution with a mass concentration of 10%, and carry out complex coagulation reaction at 40°C. Leave on for 30 minutes. Cool down to 0° C., add 10 g of 37 wt % formaldehyde aqueous solution to carry out cross-linking reaction, keep the reaction for 2 hours, and prepare the abamectin microcapsule suspension. The prepared avermectin microcapsule suspension is centrifuged, water and solvent are removed, and then the residual solid is freeze-dried to obtain the avermectin microcapsule powder.

Example 3

Dissolve 100g of sodium lignosulfonate in 200g of water, adjust the pH to 11, activate in a 70°C water bath for 1.0h, add 200g of diethylamine, slowly add 200g of propionaldehyde dropwise, complete the dropwise addition within 1h, and raise the temperature to 90°C , Continue to react for 3h to obtain sodium amino lignosulfonate solution. The obtained sodium amino lignosulfonate solution is extracted with ethanol, and the residual solid after extraction is washed with petroleum ether and then freeze-dried to obtain purified powdery sodium amino lignosulfonate.

100g of purified amino lignosulfonate wall material and 12g of sodium dodecylbenzenesulfonate are dissolved in 400g of water to prepare an aqueous solution to obtain an aqueous phase; 80g of abamectin are dissolved in 100g of pyrrolidone and 200g of ethanol mixed solvent , an organic phase was obtained. Add the organic phase to the water phase evenly within 30 minutes at 1000rpm, and then shear for 20 minutes; then adjust the pH of the dispersion to 7 with HCl solution with a mass concentration of 10%, and carry out complex coagulation reaction at 30°C , keep for 50 minutes. Cool down to 10° C., add 10 g of sodium tripolyphosphate to carry out cross-linking reaction, and keep the temperature for 1 hour to prepare the abamectin microcapsule suspension. The prepared avermectin microcapsule suspension is centrifuged, water and solvent are removed, and then the residual solid is freeze-dried to obtain the avermectin microcapsule powder.

Example 4

Dissolve 100g of sodium lignosulfonate in 300g of water, adjust the pH to 13, activate in a water bath at 50°C for 0.5h, add 100g of triethylenetetramine, slowly add 100g of glutaraldehyde dropwise, complete the dropwise addition within 0.5h, and raise the temperature To 70°C, continue to react for 2h to obtain sodium amino lignosulfonate solution. The obtained sodium amino lignosulfonate solution is extracted with ethanol, and the residual solid after extraction is washed with petroleum ether and then freeze-dried to obtain purified powdery sodium amino lignosulfonate.

100g purified amino lignosulfonate sodium wall material and 20g sodium lauryl sulfate are dissolved in 500g water to prepare an aqueous solution to obtain an aqueous phase; 200g abamectin is dissolved in 200g methanol and 300g ethanol mixed solvent, An organic phase is obtained. Add the organic phase to the water phase evenly within 30 minutes at 1200rpm, and then shear for 10 minutes; then adjust the pH of the dispersion to 8 with HCl solution with a mass concentration of 10%, and carry out complex coagulation reaction at 20°C , keep for 60 minutes. Cool down to 10° C., add 5 g of glyoxal to carry out cross-linking reaction, and keep warm for 1.5 hours to prepare the abamectin microcapsule suspension. The prepared avermectin microcapsule suspension is centrifuged, water and solvent are removed, and then the residual solid is freeze-dried to obtain the avermectin microcapsule powder.

Example 5

Dissolve 100g of sodium lignosulfonate in 300g of water, adjust the pH to 12, activate in a water bath at 60°C for 0.5h, add 150g of propylenediamine, slowly add 150g of glyoxal, dropwise within 1h, and raise the temperature to 80 °C, the reaction was continued for 4 h to obtain a sodium amino lignosulfonate solution. The obtained sodium amino lignosulfonate solution is extracted with ethanol, and the residual solid after extraction is washed with petroleum ether and then freeze-dried to obtain purified powdery sodium amino lignosulfonate.

100g purified amino lignosulfonate wall material, 1g cetyltrimethylammonium bromide and 6g Tween-80 were dissolved in 300g water to prepare an aqueous solution to obtain the aqueous phase; 80g abamectin Dissolve in 300 g of ethanol to obtain an organic phase. Add the organic phase to the water phase evenly within 30 minutes at 1500rpm, and then shear for 15 minutes; then adjust the pH of the dispersion to 6 with HCl solution with a mass concentration of 10%, and carry out complex coagulation reaction at 35°C , keep for 30 minutes. Cool down to 20°C, add 1g of epichlorohydrin to carry out cross-linking reaction, keep the reaction for 2 hours, and prepare the abamectin microcapsule suspension. The prepared avermectin microcapsule suspension is centrifuged, water and solvent are removed, and then the residual solid is freeze-dried to obtain the avermectin microcapsule powder.

Description of the effect of the embodiment

Drug loading and entrapment ratio of microcapsules in each embodiment of Table 1

The determination methods of drug loading and entrapment ratio in Table 1 are as follows:

(1) Accurately weigh a certain mass of microcapsule sample (accurate to 0.0001g), add it to about 50mL 50% DMF aqueous solution, and then break it with a cell disruptor for 10min, then transfer the obtained suspension to a 500mL volumetric flask, and dilute it with ethanol. capacity, and then let it stand for 24 hours.

(2) Take a certain amount of the supernatant in the volumetric flask, filter it with a 0.45 μm water phase filter head, and use high performance liquid chromatography to measure the content of the original drug in the filtrate. Calculate the drug loading and entrapment ratio of the microcapsules according to the following formula:

Drug loading = (mass of original drug in microcapsules)/(total mass of microcapsules) × 100%

Encapsulation rate=(total mass of microcapsule)×(drug loading)/(theoretical value of original drug in microcapsule)×100%.

Drug loading and entrapment rate are important indicators to measure the quality of microcapsules. The drug loading is closely related to the amount of wall material. A small amount of wall material means high drug loading, while a high drug loading can reduce the amount of wall material and reduce microcapsules. Capsule production cost. The entrapment rate is the utilization rate of the drug. Generally speaking, the drug price of the core material is generally much higher than that of the wall material. Increasing the entrapment rate is equivalent to increasing the utilization rate of the drug and reducing the loss of the drug. Therefore, on the premise of ensuring the quality of the microcapsules, increasing the drug loading and entrapment rate of the microcapsules can effectively reduce the production cost of the microcapsules.

As can be seen from Table 1, compared with the existing abamectin microcapsule commercial products (1.2% microcapsule suspending agent, prepared from polyurethane wall material), the microcapsules prepared in each embodiment all have higher loading capacity. Therefore, it has a certain cost advantage. And, because the lignin wall material has good anti-oxidation and anti-photolysis ability, so the avermectin microcapsule powder prepared by the present invention has good anti-ultraviolet photolysis performance, as shown in Table 2.

The former medicine of table 2, commodity microcapsule and the former medicine retention rate of embodiment 1 under ultraviolet light irradiation

As can be seen from Table 2, after the Abamectin former drug powder of the same Abamectin active ingredient content, the Abamectin commercial microcapsules and the microcapsules of Example 1 are irradiated by UVA ultraviolet lamp for 24h, test Abamectin Active ingredient retention. The result shows that after ultraviolet lamp irradiation, the active ingredient in the former drug powder of abamectin drops to 13.41%, and the active ingredient in the commercial microcapsule of abamectin drops to 67.93%, and the active ingredient in the microcapsule of embodiment 1 down to 89.44%. This shows that the anti-photolysis performance of the original drug of Abamectin is very poor, and the active ingredient of the original drug is basically ineffective after 24h of ultraviolet light irradiation, and commercial microcapsules then have certain anti-photolysis performance, and embodiment 1 microcapsules then have good Anti-photolysis properties. According to the analysis, the abamectin molecule contains conjugated double bonds, which are prone to free radical polymerization and become invalid under ultraviolet light irradiation; commercial microcapsules are reduced due to the shielding of the wall material to ultraviolet light and the protection of the original drug. The decomposition rate of the original drug; the present invention uses lignin as the main wall material, because lignin molecules contain a large number of polyphenol structures, these polyphenol structures can effectively capture the free radicals produced by ultraviolet light in the material, thereby protecting Therefore, the lignin-based wall material microcapsules of the present invention can effectively solve the defect that the original drug of abamectin is not resistant to sunlight;

Fig. 1 is the accumulative release curve of the avermectin microcapsules prepared in embodiment 1 in 50% ethanol aqueous solution under different pH conditions. As can be seen from the figure, as the pH increases, the release rate of Abamectin in the microcapsules slows down, and the release rate is the slowest at pH=8.0. This is because, as the pH decreases, the degree of ionization of the amine ions in the microcapsules increases, the charge density on the molecular chain increases, and the microcapsules change from shrinkage to loose expansion, thus increasing the release rate. It can be illustrated by Fig. 1 that the Abamectin microcapsules prepared by the present invention have certain pH responsiveness, and the release rate of Abamectin can be regulated by adjusting the pH.

Fig. 2 is the Abamectin microcapsule prepared by embodiment 1 and the existing Abamectin microcapsule commodity (1.2% microcapsule suspending agent, prepared by polyurethane wall material) in the 50% ethanol aqueous solution of pH=6.0 cumulative release curve. It can be seen from the comparison that before 20 hours of release, the release rate of the microcapsules of Example 1 was slower than that of the commercial product; after 20 hours, the release of the commercial product basically reached a balance, and the cumulative release was 89%, while the AVM‐ASL microcapsules continued to After release, the equilibrium is reached in about 60 hours, and the release amount is about 98%. Can illustrate by Fig. 2, the Abamectin microcapsule prepared by the present invention has comparable or better slow-release effect compared with existing commodity.

The specific steps of the release experiment are as follows:

Accurately weigh a certain amount of microcapsules (the quality of the abamectin contained in the microcapsule sample is equal), add it to a 100mL conical flask, dilute to volume with 50% ethanol aqueous solution of pH=6～8 and seal. Put into constant temperature shaker, carry out release experiment under 25 ℃ and 200rpm rotating speed conditions, take 1mL supernatant at intervals to measure its avermectin content, and supplement 1mL50% ethanol aqueous solution to keep volume constant. Plot cumulative release curves.

Figure 3 is a microscopic image of the microcapsules prepared in Example 1. It can be seen from the figure that the prepared microcapsules are uniform in size, particle size <5 μm, and uniformly dispersed.

The above implementation effects show that the avermectin microcapsules prepared by the present invention have comparable or better sustained-release effects compared with existing commercial microcapsules, and have higher drug loading and entrapment ratio simultaneously, and the wall material raw materials A wide range of sources and low prices have cost advantages. Since the lignin-based wall material contains a large amount of polyphenol structure, it has significant photolysis resistance, and can more effectively solve the defect of avermectin that it is not resistant to sunlight compared with commercial microcapsules. The lignin-based wall material is an environmentally friendly modified natural polymer material, non-toxic and harmless, and can be naturally degraded into fertilizer in nature. In summary, the microcapsules prepared by the present invention have more outstanding performance advantages than the current commercial microcapsules, and have great industrial application prospects.

Claims (4)

1. a kind of method that application lignin-base wall material prepares avermectin microcapsule powder, it is characterised in that comprise the following steps：

1) in terms of mass fraction, the amido sodium lignin sulfonate wall material and 5~20 parts of emulsifying agents of 100 parts of purifications are dissolved in 200~ The aqueous solution is configured in 500 parts of water, water phase is obtained；

2) the former medicine of AVM is dissolved in organic solvent, obtains organic phase；

3) organic phase is even added in water phase in rotating condition, then is sheared 10~20 minutes；Then dispersion liquid is adjusted PH value carries out complex coacervation 30~60 minutes to 6~8 at 20~40 DEG C；0~20 DEG C is cooled to, 1~10 part of crosslinking is added Agent carries out cross-linking reaction 1~2 hour, and avermectin microcapsule suspension is obtained；

4) by obtained avermectin microcapsule suspension centrifugation, water and solvent are removed, it is then that residual solid freezing is dry It is dry, obtain avermectin microcapsule powder；

The amido sodium lignin sulfonate wall material is prepared via a method which：By sodium lignin sulfonate it is soluble in water be configured to it is wooden Plain sulfonic acid sodium water solution, adjusts the pH value of solution to 10.0~13.0, and 0.5~1.0h is activated at 50~70 DEG C；Amination is added to change Property agent, then be added dropwise aldehydes reagent, after completion of dropping, 70~90 DEG C react 2~4h, obtain amido sodium lignin sulfonate molten Liquid；The amido lignin sulfonic acid sodium solution that will be obtained is stripped with alcohol reagent, and the residual solid thing after extracting uses oil again Ether is washed, and debris carries out freeze-drying again, you can the powdery amido sodium lignin sulfonate wall material for being purified；The amine Change reagent is diethylamine, propane diamine, triethylamine, diethylenetriamine or triethylene tetramine；The aldehydes reagent be formaldehyde, acetaldehyde, Propionic aldehyde, glyoxal or glutaraldehyde；The alcohol reagent is one or more in methyl alcohol, ethanol, propyl alcohol, isopropanol and butanol；

The emulsifying agent is lauryl sodium sulfate, neopelex, cetomacrogol 1000, cetyl trimethyl bromine Change one or more in ammonium and Tween-80；

The organic solvent is one or more in dimethyl sulfoxide (DMSO), pyrrolidones, dichloromethane, methyl alcohol, ethanol；

The crosslinking agent is the one kind in sodium tripolyphosphate, formaldehyde, glyoxal, glutaraldehyde, epoxychloropropane；

In terms of mass fraction, the organic phase is that 20~200 parts of the former medicine of AVM are dissolved in 200~500 parts of organic solvents Obtain；The lignin sulfonic acid sodium water solution is that 100 parts of sodium lignin sulfonates are dissolved in 150~400 parts of water to be configured to；It is described The addition of amination modifying agent is 20~200 parts；The addition of the aldehydes reagent is 20~200 parts；

The rotating speed of the rotating condition is 500-1500rpm；Time organic phase being even added in water phase is 20-40 Minute.

2. the method that application lignin-base wall material according to claim 1 prepares avermectin microcapsule powder, its feature exists In in terms of mass fraction, the dropwise addition is 20~200 parts of aldehydes reagents of addition in 0.5~1.0h.

3. the method that application lignin-base wall material according to claim 1 prepares avermectin microcapsule powder, its feature exists In in terms of mass fraction, it is anti-by 100 parts that the amido lignin sulfonic acid sodium solution alcohol reagent that will be obtained is stripped The amido lignin sulfonic acid sodium solution that should be obtained is stripped with 100~300 parts of alcohol reagents.

4. the avermectin microcapsule powder that prepared by a kind of lignin-base wall material, it is characterised in that：It is by claim any one of 1-3 Described method is prepared.