A preparation method of microcapsule suspension containing brassinolide

Abstract

The present invention belongs to the technical field of pesticide compositions, and specifically relates to a method for preparing a microcapsule suspension containing brassinolide. The method for preparing a microcapsule suspension containing brassinolide of the present invention comprises the following steps: (1) dissolving brassinolide and a stabilizer in a solvent, adding an isocyanate capsule material to mix, and obtaining an oil phase; using water, an emulsifier, and a defoamer to prepare an aqueous phase; (2) after the oil phase and the aqueous phase are uniformly mixed, adding an active hydrogen component capsule material to mix, heating and curing to obtain a microencapsulated semi-finished product, and then modulating to obtain a microcapsule suspension. The present invention adopts an interfacial polymerization method, and obtains a microencapsulated semi-finished product by polymerizing an isocyanate capsule material and an active hydrogen component capsule material at an oil-water interface. The reaction process is simple and controllable, does not require excessive adjustment, has a wide range of applications, and has an encapsulation rate of more than 90% for the original drug, thereby improving the stability of such preparations, reducing the decomposition of the original drug, and improving the utilization rate of the original drug.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticide compositions, and particularly relates to a method for preparing a microcapsule suspension containing brassinolide. Background Art

[0002] Brassinolide is an endogenous plant growth regulator substance with a similar structure that was isolated and identified from nature in the 1970s. Brassinolide compounds are widely used in agricultural production, promoting root growth in the seedling stage, growth in the vegetative stage, fruiting in the reproductive organs, and enhancing plant resistance.

[0003] Common brassinolides include: 14-hydroxybrassinolide, 24-epibrassinolide, 28-homobrassinolide, and propionylbrassinolide. Their chemical structures are as follows. They have similar biological activities. Brassinolide technical is a white solid, slightly soluble or insoluble in water, soluble in organic solvents such as alcohols and benzene, with a pH value of weakly acidic to neutral, and will decompose under alkaline conditions.

[0004]

[0005]

[0006] Pesticide microcapsule suspension (CS) is a kind of natural polymer and synthetic polymer, which is chemically or physically wrapped around the target molecule to form a core-shell structure container, which protects the target molecule or temporarily stores it in the container formed by the core-shell. CS consists of two parts: the capsule wall and the capsule core. The capsule core is the target molecule in liquid state or solid particles in the nanometer to micrometer scale; the capsule wall is a natural polymer or a synthetic polymer. Compared with conventional dosage forms, CS has the functions of controlled release, prolonged efficacy, improved pesticide utilization, reduced pesticide toxicity, delayed pesticide decomposition, and reduced environmental pollution.

[0007] The Chinese invention patent with publication number CN112841194A discloses a method for preparing a 28-homobrassinolide microcapsule suspension, which is prepared by mixing an auxiliary agent and a raw drug, grinding the mixture, and adding a capsule wall material. This method uses gelatin and other capsule wall materials to directly mix with the raw drug to form an encapsulation, which has a low encapsulation rate and poor stability of the encapsulation effect, which directly affects the actual use effect of the microcapsule suspension. Summary of the invention

[0008] The purpose of the present invention is to provide a method for preparing a microcapsule suspension containing brassinolide, so as to solve the technical problems of low encapsulation rate and unstable encapsulation effect in the preparation of microcapsule suspension in the prior art.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A method for preparing a microcapsule suspension containing brassinolide comprises the following steps:

[0011] (1) dissolving brassinolide and a stabilizer in a solvent, adding isocyanate capsule material and mixing to obtain an oil phase; preparing an aqueous phase using water, an emulsifier, and a defoamer;

[0012] (2) After the oil phase and the water phase are evenly mixed, the active hydrogen component capsule material is added and mixed, and the microencapsulation semi-finished product is obtained after heating and curing, and then the microcapsule suspension is obtained after modulation.

[0013] The present invention adopts an interfacial polymerization method, and obtains a microencapsulated semi-finished product by polymerizing an isocyanate capsule material and an active hydrogen component capsule material at an oil-water interface. The reaction process is simple and controllable, does not require excessive adjustment, has a wide range of applications, and has an encapsulation rate of more than 90% for the original drug, thereby improving the stability of such preparations, reducing the decomposition of the original drug, and improving the utilization rate of the original drug.

[0014] Preferably, the isocyanate capsule material is diisocyanate, and the mass ratio of the sum of the brassinolide, stabilizer, and solvent to the isocyanate capsule material is (10-8): 1. Comparative tests show that within the above ratio range, the encapsulation rate is high, the cross-linking degree is appropriate, and no large particles exist.

[0015] Further preferably, the total mass fraction of the sum of the brassinolide, stabilizer and solvent in the system is 4-5%. When the total mass fraction is controlled within the above range, the reaction is stable and a microcapsule suspension preparation product with excellent encapsulation efficiency and other indicators can be obtained.

[0016] In terms of encapsulation effect and raw material cost, preferably, the diisocyanate is selected from any one of diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate, toluene diisocyanate and lysine diisocyanate.

[0017] In terms of encapsulation effect and raw material cost, preferably, the active hydrogen component capsule material is any one of a diol or a diamine; the diol is any one of ethylene glycol, polyethylene glycol, and propylene glycol; the diamine is any one of propylenediamine, tetramethylethylenediamine, tetramethylpropylenediamine, and tetrahydroxypropylethylenediamine.

[0018] In order to achieve stable and efficient use of the microcapsule suspension, preferably, the brassinolide is any one of 14-hydroxybrassinolide, 24-epibrassinolide, 28-homobrassinolide, and propionylbrassinolide; and the content of the brassinolide in the microcapsule suspension is 0.001 to 0.2%.

[0019] Preferably, the stabilizer is one or more of epoxy linseed oil, epoxy soybean oil, liquid xylitol, and butanol; the mass ratio of the brassinolide to the stabilizer is (0.001-0.2):(2-6). The stabilizer and the brassinolide technical are encapsulated in the isocyanate capsule material, further ensuring the stability of the brassinolide technical.

[0020] Preferably, the solvent is one or more of butyl acetate, ethyl acetate, deuterated chloroform, butanol, dimethylformamide, and dimethyl sulfoxide; the mass ratio of the brassinolide to the solvent is (0.001-0.2):(2-11). The solvent is used to dissolve the brassinolide technical and adjust the oil phase ratio.

[0021] Preferably, the temperature of the heating and curing is 45-55° C. Comparative experiments show that at the above reaction temperature, capsule formation is good and the cross-linking speed is optimal.

[0022] In order to further ensure the encapsulation efficiency of the microencapsulated semi-finished product, preferably, the active hydrogen component capsule material is added by dropwise addition at a dropwise addition speed of 0.1 to 0.3 mL / min.

[0023] In order to further improve the use effect, suspension, dispersibility, physical stability, chemical stability and other properties of the microcapsule suspension, preferably, the modulation includes mixing the microencapsulated semi-finished product and the processing aid to form the microcapsule suspension; the processing aid is selected from one or more of a thickener, an antifreeze agent, a preservative, and a dispersant. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The process flow chart of the present invention for preparing a microcapsule suspension containing brassinolide;

[0025] Figure 2 Comparison of CS release rates of capsule materials with different active hydrogen components when the core material ratio is 10:1 (SL is the control);

[0026] Figure 3 Comparison of CS release rates of capsules with different active hydrogen components when the core material ratio is 8:1 (SL is the control). DETAILED DESCRIPTION

[0027] The present invention adopts an interfacial polymerization method to generate a microencapsulated semi-finished product by polymerizing an isocyanate capsule material and an active hydrogen component capsule material at an oil-water interface. When the active hydrogen component capsule material is a polyol or a polyamine, the reaction process is as follows:

[0028]

[0029]

[0030] The process of preparing the microcapsule suspension of the present invention is further described in detail below.

[0031] (1) Processing technology of microcapsule suspension

[0032] The processing flow chart of microcapsule suspension is as follows Figure 1 shown.

[0033] 1) preparing the oil phase: dissolving brassinolide and stabilizer in a solvent, adding isocyanate capsule material and mixing to obtain an oil phase;

[0034] 2) preparing the aqueous phase: preparing the aqueous phase using water, an emulsifier and a defoamer;

[0035] 3) Obtaining microencapsulated semi-finished product:

[0036] Transfer the aqueous phase to a beaker of suitable size, turn on the high-speed homogenizing emulsifier, slowly add the oil phase to the shearing beaker, emulsify and shear, and shear until the droplet morphology is intact under a microscope to form a uniform O / W emulsion, transfer it to a three-necked flask, and slowly add an appropriate amount of active hydrogen component capsule material with a constant pressure separatory funnel at a dropping speed of 0.1-0.3 mL / min. During this period, the temperature is controlled at 30-40°C, and then heated to 45-55°C at a speed of 1°C / min, and then kept warm and cured for 3-4 hours to obtain a microencapsulated semi-finished product.

[0037] During the microencapsulation process, the core material ratio is different, and the mass of each component capsule material required for synthesizing the capsule wall also changes accordingly. Under the premise that the proportion of capsule material A (i.e., isocyanate capsule material) is fixed, the amount of corresponding water phase capsule material B (i.e., active hydrogen component capsule material) is calculated according to the reaction equation combined with the corresponding molar ratio and molecular weight ratio, as shown in Tables 1 and 2.

[0038] In the present invention, the core material ratio is the ratio of the total mass of brassinolide, stabilizer, and solvent to the mass of isocyanate capsule material. Because the content of the active ingredient (brassinolide) in the system is ultra-low, the total mass of brassinolide, stabilizer, and solvent (regarded as the mass of the oil phase) can be roughly evaluated by the sum of the masses of the solvent and stabilizer. In the following embodiments, the total mass fraction of the solvent and stabilizer in the system is fixed at 4%. At this time, the core material is 4%. When the core material ratio (capsule-core-capsule material ratio) is 10:1, the mass fraction of the isocyanate capsule material in the system is 0.4%. At this time, the corresponding amount of the polyol component is converted according to the theoretical reaction equivalent (complete reaction) of the isocyanate component and the active hydrogen component. When the core material ratio (capsule-core-capsule material ratio) is 8:1, the mass fraction of the isocyanate capsule material in the system is 0.5%, and it is processed in the same manner as above. The relevant conversion formulas and the amounts of raw materials under typical core material ratios are described as follows:

[0039]

[0040]

[0041] Table 1 Amount of active hydrogen component capsule material when the core material ratio is 10:1 and the mass content of isocyanate capsule material is 0.4%

[0042]

[0043] Table 2 The amount of active hydrogen component capsule material when the core material ratio is 8:1 and the mass content of isocyanate capsule material is 0.5%

[0044]

[0045] 4) Preparation of microcapsule suspension

[0046] The obtained microencapsulated semi-finished product is transferred to a beaker, and appropriate amounts of thickener, antifreeze agent, preservative and dispersing wetting agent are added, and the continuous phase is used to make up to 100%; and the mixture is mixed evenly to obtain a microcapsule suspension containing brassinolide.

[0047] (2) Raw material ratio and function description

[0048] The raw material ratios of the microcapsule suspension containing brassinolide prepared by the present invention (if not otherwise specified, "%" represents mass fraction) are shown in Table 3:

[0049] Table 3 Ratio of raw materials for microcapsule suspension

[0050]

[0051]

[0052]

[0053] The role of raw materials in the formula and the type of selection:

[0054] Solvent: used to dissolve brassinolide technical and adjust the oil phase ratio; selected from one or more of butyl acetate, ethyl acetate, deuterated chloroform, butanol, dimethylformamide DMF, dimethyl sulfoxide DMSO, etc.

[0055] Stabilizer: ensure the stability of the original drug, ensure that low-content brassinolide is not lost, and adjust the oil phase to have a suitable ratio; selected from one or more of epoxy linseed oil, epoxy soybean oil, liquid xylitol, butanol, etc.

[0056] Emulsifier: forms a stable and uniform emulsion system; selected from one or more of block polyether, octylphenol polyoxyethylene ether, methyl oleate, etc.

[0057] Capsule material: forms capsule wall and encapsulates the phase containing brassinolide compound; selected from polyurea resin and polyurethane. Said capsule material is obtained by polymerization of diol or diamine and isocyanate capsule material at oil-water interface.

[0058] Wetting and dispersing agent: promotes system dispersion and improves the wetting of the preparation on the crop surface; one or more of polycarboxylates, polyether phosphates, aromatic sulfonates, carboxylic acid polyethers, alcohol ethers, sodium lignin sulfonate, etc.

[0059] Thickener: forms good system viscosity to ensure the stability of the preparation; one or more of xanthan gum, aluminum magnesium silicate, diutan gum, hydroxypropyl methylcellulose, etc.

[0060] Defoaming agent: reduce the foam generated during processing and improve processing efficiency; one or more of silicone, mineral oil, etc.

[0061] Preservatives: To avoid microbial contamination of the preparation; one or more of kasone, benzoic acid, etc.

[0062] Antifreeze: Improves the performance of the preparation under low temperature conditions, one or more of urea, ethylene glycol, glycerol, propylene glycol, etc.

[0063] Unless otherwise specified, the materials involved in the above invention process are all commercially available products. The sources of the raw materials involved in the examples are shown in Table 4:

[0064] Table 4 Material description

[0065]

[0066]

[0067]

[0068] The D90 particle size of the microcapsule suspension prepared by the above method is about 2.0 to 5.0 μm, for example, the general D90 particle size is about 2.4 to 4.5 μm, showing a high consistency of particle size.

[0069] 1. The specific embodiment of the preparation method of the microcapsule suspension containing brassinolide of the present invention is as follows:

[0070] Embodiments 1 to 4

[0071] The preparation method of the microcapsule suspension containing brassinolide in Examples 1 to 4 is to prepare 0.001% brassinolide microcapsule suspension, the core material ratio is designed to be 10:1, and the amount of each raw material is shown in Table 5.

[0072] Table 5 Amounts of components in 0.001% brassinolide microcapsule suspension prepared in Examples 1 to 4

[0073]

[0074]

[0075] The specific preparation method is described as follows:

[0076] Weigh 0.001% brassinolide technical (100% amount) according to the proportion, add 2% butyl acetate (Jinan Luying Chemical), 2% liquid xylitol (Shandong Yuchuang Biotechnology), take 0.4% diphenylmethane diisocyanate solution into a beaker, mix evenly to form an oil phase; add an appropriate proportion of continuous phase and 2% OP-10 (Shandong Kemai Environmental Protection Technology) to form a water phase; start shearing at a speed of 10000r / min; slowly add the oil phase to the water phase, and shear emulsify after the addition is completed; observe the emulsion through an optical microscope, and stop shearing when the emulsion is uniform, the particle size is appropriate, and a stable O / W emulsion is formed; Transfer the emulsion to a three-necked flask, install the equipment, and start stirring at 300 r / min; slowly add diamine or diol (Examples 1 to 4 are propylene diamine, propylene glycol, propylene diamine, and propylene glycol, respectively) according to the mass of the corresponding substances in Table 1 (the amount of capsule material in Table 1 is the sum of the masses of the isocyanate component and the active hydrogen component, wherein the isocyanate component is fixed to a theoretical value of 0.4%, and the active hydrogen component can fluctuate up and down by a small amount, which is within the acceptable error range), the time is 1 hour; then turn on the heating, slowly heat to 50°C, and keep warm for 3-4 hours to complete the reaction; naturally cool to room temperature to obtain a microencapsulated semi-finished product containing brassinolide.

[0077] The semi-finished microencapsulated product in the three-necked flask was transferred to a beaker and stirred; 3% Featdis DCP (Shanghai Xuezhuo) and 1% ULTRAZINE NA (sodium lignin sulfonate, Nanjing Jierun), 1.5% magnesium aluminum silicate (Jinan Yongtai Chemical), 0.3% diutan (Solvay), 0.5% defoamer AF1501 (Guangzhou Fangzhong Chemical), 0.3% kason (Jinan Haoran Chemical) and 4% propylene glycol were added, and the continuous phase was used to make up to 100%; the mixture was mixed evenly to obtain a microcapsule suspension containing brassinolide.

[0078] Embodiments 5 to 8

[0079] The preparation method of the microcapsule suspension containing brassinolide in Examples 5 to 8 is to prepare a 0.01% brassinolide microcapsule suspension, the core material ratio is designed to be 8:1, and the amount of each raw material is shown in Table 6.

[0080] Table 6 Amounts of components in 0.01% brassinolide microcapsule suspension prepared in Examples 5 to 8

[0081]

[0082] The specific preparation method is described as follows:

[0083] Weigh 0.01% brassinolide technical (100% weight) according to the proportion, add 2% ethyl acetate (Jinan Tengbo Chemical), 2% epoxy linseed oil, and 0.5% isophorone diisocyanate (IPDI) solution into a beaker, mix well to form an oil phase; take an appropriate proportion of continuous phase and 2% OP-10 (Shandong Kemai Environmental Protection Technology) to form a water phase; start shearing at a speed of 10000r / min; slowly add the oil phase to the water phase, and shear emulsify after the addition is completed; observe under an optical microscope In the case of emulsion, when the emulsion is uniform, the particle size is appropriate, and a stable O / W emulsion is formed, the shearing can be stopped; the emulsion is transferred to a three-necked flask, the equipment is installed, and stirring is started at 350r / min; diamine or diol (Examples 5 to 8 are propylene diamine, propylene glycol, propylene diamine, and propylene glycol, respectively) is slowly added according to the mass of the corresponding substance in Table 2 for 1 hour, and then heating is turned on, slowly heated to 50°C, and heat-preserved for curing for 3-4 hours; the temperature is naturally cooled to room temperature to obtain a microencapsulated semi-finished product containing brassinolide.

[0084] The semi-finished microencapsulated product in the three-necked flask was transferred to a beaker and stirred; 3% Featdis DCP (Shanghai Xuezhuo) and 1% PHODASURF 860-P (Solvay), 1.5% magnesium aluminum silicate (Jinan Yongtai Chemical), 0.3% diutanol (Solvay), 0.5% defoamer AF1501 (Guangzhou Fangzhong Chemical), 0.3% kason (Jinan Haoran Chemical) and 4% propylene glycol (Tianjin Zhonghe Shengtai) were added, and the continuous phase was used to make up to 100%; the mixture was mixed evenly to obtain a microcapsule suspension containing brassinolide.

[0085] Examples 9 to 12

[0086] The preparation method of the microcapsule suspension containing brassinolide of Examples 9 to 12 is to prepare 0.05% brassinolide microcapsule suspension, the core material ratio is designed to be 10:1, and the amount of each raw material is shown in Table 7.

[0087] Table 7 Amounts of components in 0.05% brassinolide microcapsule suspension prepared in Examples 9 to 12

[0088]

[0089] The specific preparation method is described as follows:

[0090] Weigh 0.05% brassinolide technical (100% weight) according to the proportion, add 2% deuterated chloroform (Shanhu Hubei Chengfeng Chemical) and 2% liquid xylitol, mix well to form an oil phase; take 0.4% hexamethylene diisocyanate (HDI) solution into a beaker, add an appropriate proportion of continuous phase and 2% ULTRARIC 5000HM (Shanghai Xuezhuo) emulsifier to form an aqueous phase; start shearing at a speed of 10000r / min; slowly add the oil phase dropwise to the aqueous phase, and shear and emulsify after the addition is completed; observe the emulsion through an optical microscope, and stop shearing when the emulsion is uniform, the particle size is appropriate, and a stable O / W emulsion is formed; transfer the emulsion to a three-necked flask, install the equipment, and start stirring at 300r / min; slowly add diamine (Examples 9 to 12 are propylene diamine, tetramethylethylenediamine, tetramethylpropylene diamine, and tetrahydroxypropylethylenediamine, respectively) according to the mass of the corresponding substances in Table 1, and the time is 1h; then start heating, slowly heat to 50°C, and keep warm for 3-4h; naturally cool to room temperature to obtain a microencapsulated semi-finished product containing brassinolide.

[0091] Transfer the microencapsulated semi-finished product in the above three-necked flask to a beaker and stir; add 3% BREAK THRU DA655 (Evonik) and 1% Featdis SC800 (Shanghai Xuezhuo), 1.5% magnesium aluminum silicate (Jinan Yongtai Chemical), 0.3% hydroxypropyl methylcellulose (Hebei Yanxing Chemical), 0.5% AF1501 (Guangzhou Fangzhong Chemical), 0.3% sodium benzoate (Jinan Qingtian Chemical) and 4% polyethylene glycol 200 (Jinan Taiwang Chemical), and make up to 100% with a continuous phase; mix well to obtain a microcapsule suspension containing brassinolide.

[0092] Embodiments 13 to 16

[0093] The preparation method of the microcapsule suspension containing brassinolide of Examples 13 to 16 is to prepare 0.1% brassinolide microcapsule suspension, the core material ratio is designed to be 8:1, and the amount of each raw material is shown in Table 8.

[0094] Table 8 Amounts of components in 0.1% brassinolide microcapsule suspension prepared in Examples 13 to 16

[0095]

[0096]

[0097] The specific preparation method is described as follows:

[0098] Weigh 0.1% brassinolide technical (percentage), add appropriate proportion of butanol (Qilu Petrochemical) solvent and 2% epoxy linseed oil, mix well to form oil phase; take 0.5% 4,4-dicyclohexylmethane diisocyanate (HMDI) into a beaker, add appropriate proportion of continuous phase and 2% ULTRARIC 5000HM (Shanghai Xuezhuo) to form an aqueous phase; start shearing at a speed of 10000r / min; slowly add the oil phase dropwise to the aqueous phase, and shear and emulsify after the addition is completed; observe the emulsion through an optical microscope, and stop shearing when the emulsion is uniform, the particle size is appropriate, and a stable O / W emulsion is formed; transfer the emulsion to a three-necked flask, install the equipment, and start stirring at 300r / min; slowly add diamine or diol (propylene glycol, ethylene glycol, propylene glycol, and ethylene glycol, respectively) according to the mass of the corresponding substance in Table 2 for 1h; then start heating, slowly heat to 55°C, and keep warm for 3-4h; naturally cool to room temperature to obtain a microencapsulated semi-finished product containing brassinolide.

[0099] The microencapsulated semi-finished product in the three-necked flask was transferred to a beaker and stirred; 4% Atlox Metasoerse 550S (Heda), 1% Featdis SC800 (Shanghai Xuezhuo), 1.5% magnesium aluminum silicate (Jinan Yongtai Chemical), 0.2% hydroxypropyl methylcellulose, 0.5% TENSIOFIX LO51 (Shanghai Teske), 0.3% Kason (Jinan Haoran Chemical) and 4% urea (Jinan Taiwang Chemical) were added, and the continuous phase was used to make up to 100%; the mixture was mixed evenly to obtain a microcapsule suspension containing brassinolide.

[0100] Examples 17 to 20

[0101] The preparation method of the microcapsule suspension containing brassinolide of Examples 17 to 20 is to prepare a 0.15% brassinolide microcapsule suspension, the core material ratio is designed to be 10:1, and the amount of each raw material is shown in Table 9.

[0102] Table 9 Amounts of components in 0.15% brassinolide microcapsule suspension prepared in Examples 17 to 20

[0103]

[0104]

[0105] The specific preparation method is described as follows:

[0106] Weigh 0.15% brassinolide technical (100% weight) according to the proportion, add appropriate proportion of dimethylformamide (Jinan Xinshun Chemical) and 2% epoxidized soybean oil, mix well to form oil phase; take 0.4% toluene diisocyanate (TDI) solution into a beaker, add appropriate proportion of continuous phase and 2% CS-100A (Heda), forming an aqueous phase; turning on shearing, the speed is 10000r / min; slowly adding the oil phase to the aqueous phase, and shearing and emulsifying after the addition is completed; observing the emulsion through an optical microscope, when the emulsion is uniform, the particle size is appropriate, and a stable O / W emulsion is formed, the shearing can be stopped; the emulsion is transferred to a three-necked flask, the equipment is installed, and stirring is started at 300r / min; according to the mass of the corresponding substances in Table 1, diols (propylene glycol, polyethylene glycol, propylene glycol, polyethylene glycol in Examples 17 to 20, respectively) are slowly added for 1 hour; then heating is turned on, slowly heated to 50°C, and heat preservation and curing is carried out for 3-4 hours; the temperature is naturally cooled to room temperature to obtain a microencapsulated semi-finished product containing brassinolide.

[0107] The microcapsule solution in the three-necked flask was transferred to a beaker and stirred; 3% BREAK THRU DA655 (Evonik), PHODASURF 860-P (Solvay), 1.0% magnesium aluminum silicate (Jinan Yongtai Chemical), 0.3% xanthan gum (Renqiu Litian Chemical), 0.5% TENSIOFIX LO51 (Shanghai Tesko), 0.3% Kason (Jinan Haoran Chemical) and 4% ethylene glycol (Jinan Taiwang Chemical) were added, and the continuous phase was used to make up to 100%; the mixture was mixed evenly to obtain a microcapsule suspension containing brassinolide.

[0108] Examples 21 to 24

[0109] The preparation method of the microcapsule suspension containing brassinolide of Examples 21 to 24 is to prepare 0.2% brassinolide microcapsule suspension, the core material ratio is designed to be 8:1, and the amount of each raw material is shown in Table 10.

[0110] Table 10 Amounts of components in 0.2% brassinolide microcapsule suspension prepared in Examples 21 to 24

[0111]

[0112] The specific preparation method is described as follows:

[0113] Weigh 0.2% brassinolide technical (100% weight) according to the proportion, add appropriate proportion of dimethyl sulfoxide (Jinan Xinchaorui) and 2% butanol, mix well to form oil phase; take 0.5% lysine diisocyanate (LDI) solution into a beaker, add appropriate proportion of continuous phase and 2% ULTRARIC 5000HM to form an aqueous phase; start shearing at a speed of 10000r / min; slowly add the oil phase dropwise to the aqueous phase, and shear and emulsify after the addition is completed; observe the emulsion through an optical microscope, and stop shearing when the emulsion is uniform, the particle size is appropriate, and a stable O / W emulsion is formed; transfer the emulsion to a three-necked flask, install the equipment, and start stirring at 300r / min; slowly add diols (propylene glycol, polyethylene glycol, ethylene glycol, and ethylene glycol, respectively) according to the mass of the corresponding substances in Table 2, and complete it in about 1 hour; then start heating, slowly heat to 50°C, and keep warm for 3-4 hours; naturally cool to room temperature to obtain a microencapsulated semi-finished product containing brassinolide.

[0114] The microencapsulated semi-finished product in the three-necked flask was transferred to a beaker and stirred; 1% Atlox Metasoerse550S (Heda), 3% PHODASURF 860-P (Solvay), 1.5% magnesium aluminum silicate (Jinan Yongtai Chemical), 0.3% xanthan gum (Renqiu Litian Chemical), 0.5% TENSIOFIX LO51 (Shanghai Teske), 0.3% sodium benzoate (Jinan Qingtian Chemical) and 4% glycerol (Jinan Taiwang Chemical) were added, and the continuous phase was used to make up to 100%; the mixture was mixed evenly to obtain a microcapsule suspension containing brassinolide.

[0115] 2. Experimental Examples

[0116] Experimental Example 1

[0117] This experimental example tests the encapsulation efficiency, suspension rate, pH value and other properties of the microcapsule suspension prepared in each embodiment. The detection method of each experimental item is as follows:

[0118] (1) Encapsulation efficiency test

[0119] 1) Preparation of standard solution

[0120] Weigh 0.02 g (accurate to 0.0002 g) of brassinolide standard sample into a 10 mL volumetric flask, dissolve and dilute to the scale with methanol, accurately transfer 1 mL of the above solution into a 5 L volumetric flask, add 2.0 mL of phenylboric acid methanol solution with a concentration of 2.5 mg / mL, make up to about 50 mL with methanol, shake well, and react at room temperature for 1.0 h. After the reaction is completed, dilute to the scale with methanol, shake well, and filter.

[0121] 2) Determination of free mass fraction

[0122] Weigh the concentrated sample solution containing 0.02 g (accurate to 0.0002 g) of brassinolide into a 50 mL volumetric flask, add 2.0 mL of 2.5 mg / mL phenylboric acid methanol solution, make up to about 50 mL with methanol, shake well, and react at room temperature for 1 h. After the reaction is complete, dilute to the scale with methanol, shake well, and filter.

[0123] 3) Determination of total mass fraction

[0124] Weigh the concentrated sample solution containing 0.02g of brassinolide (accurate to 0.0002g) in a 50mL volume, add 2.0mL of phenylboric acid methanol solution with a concentration of 2.5mg / mL, add 15mL of acetone, ultrasonicate until completely dissolved, then add methanol to about 50mL, shake well, and react at room temperature for 1h. After the reaction is complete, dilute to the scale with methanol, shake well, filter, add 10mL of acetone, and ultrasonicate to dissolve.

[0125] Under the above operating conditions, after the instrument is stable, several injections of standard solution are continuously injected. When the relative change of the peak area of ​​two adjacent injections of brassinolide is less than 1.0%, the measurement is carried out in the order of standard solution, sample solution, sample solution, and standard solution.

[0126] 4) Calculate the encapsulation efficiency

[0127]

[0128] (2) Suspension rate detection

[0129] Weigh 100g of the sample (accurate to 0.0002g), and proceed according to 4.2 of GB / T 14825-2006. Transfer all the 1 / 10 (i.e. 25ml) of the suspension and the sediment remaining at the bottom of the measuring cylinder to a 100ml volumetric flask. Wash the measuring cylinder with 60ml of methanol three times, add the washing liquid to the same volumetric flask, and make up to volume with methanol. Determine the total mass of brassinolide and calculate the suspension rate according to the encapsulation rate test method.

[0130] (3) pH value (pH meter method)

[0131] Tested according to GB / T 1601

[0132] Weigh 1g of the sample into a 100mL beaker, add 100mL of water, stir vigorously for 1 min, and let stand for 1 min; insert the rinsed glass electrode and saturated calomel electrode into the sample solution and measure its pH value. Perform at least three parallel measurements, and the absolute difference of the measurement results should be less than 1. The arithmetic mean is the pH value of the sample.

[0133] (4) Wet screening test

[0134] According to GB / T 1601, take 20g and put it on a 200-mesh (75μm) sieve. Use water flow to promote it to pass through the sieve. Then put it in an oven for drying. Weigh the mass that does not pass through the sieve and calculate the wet sieve passing percentage.

[0135] (5) Long-lasting foaming

[0136] Tested according to GB / T 28137.

[0137] Take 1g and add it into the specified measuring cylinder, and make up to 80% of the capacity. In 1 min, turn it upside down 30 times at a constant speed, open the ground glass stopper and let it stand for 1 min, and calculate the foam height.

[0138] (6) Density

[0139] Weigh the mass of 25ml density bottles A and B to get m A and m B ; Add pure water to 25ml density bottle A, put the sample into the 25ml density bottle, remove bubbles with ultrasound, and wipe the surface dry; put the density bottles A and B in a constant temperature water bath at 25±0.5℃ for 30 to 40 minutes after stoppering; adjust the liquid level of the density bottle to the mark of the capillary with filter paper. Wipe the density bottle dry and weigh it to get the mass m1 and m2; substitute the measured data into the formula to calculate the drug density p.

[0140]

[0141] (7) Particle size D90

[0142] Dandong Better Laser Particle Size Analyzer 9300ST was used for rapid analysis.

[0143] (8) Dumping

[0144] After mixing enough sample, place part of it in the weighed measuring cylinder (including stopper) in time, fill it to 8 / 10 of the volume of the measuring cylinder, plug it tightly with ground stopper, weigh it, and leave it for 24 hours. Open the stopper, rotate the measuring cylinder 135 degrees from the upright position, pour it for 60 seconds, and then invert it for 60 seconds, and weigh the cylinder and stopper again. Pour water (20℃) equivalent to 80% of the volume of the measuring cylinder into the measuring cylinder, plug it tightly with ground stopper, invert the measuring cylinder 10 times, pour the contents according to the above operation, and weigh the measuring cylinder and stopper for the third time.

[0145] (9) Low temperature stability

[0146] According to 2.1 of GB / T 19136-2003. After heat storage, place at room temperature for 24 hours and then test the relative decomposition rate of brassinolide compounds to be no more than 5%, and the mass fraction of free brassinolide compounds is allowed to increase to within 10% of the total effective ingredients.

[0147] (10) Thermal storage stability

[0148] According to 2.1 of GB / T 19136-2003. After heat storage, place at room temperature for 24 hours and then test the relative decomposition rate of brassinolide compounds to be no more than 5%, and the mass fraction of free brassinolide compounds is allowed to increase to within 10% of the total effective ingredients.

[0149] (11) Freeze-thaw stability

[0150] Take a certain amount of sample and seal it in a special bottle. Perform four cycles between (20±2)℃ and (-10±2)℃. Each cycle consists of freezing for 18 hours and thawing for 6 hours. After the cycle, return to room temperature, observe the appearance, and measure various indicators of the product according to the standard.

[0151] (12) Sustained release performance

[0152] Weigh the sample solution containing 0.002 g of brassinolide (accurate to 0.0002 g) into a 150 mL conical flask, shake it to make it uniform, then add 130 ml of dilution medium, cover it with a lid and place it on a horizontal rotating device (Lichen Technology, constant temperature oscillator ZD-85), set the rotation speed of the bottle to (70 ± 10) r / min, start timing at the same time, stop the machine at the corresponding time, and immediately take the supernatant and test the brassinolide content in the supernatant according to the method in (1) Encapsulation efficiency test

[0153] The test results of the 0.001% brassinolide microcapsule suspension prepared in the present invention are shown in Table 11.

[0154] Table 11 Test results of 0.001% brassinolide microcapsule suspension prepared in Examples 1 to 4

[0155]

[0156]

[0157] In the embodiment of 0.001% brassinolide microcapsule suspension, butyl acetate is selected as the solvent, which is miscible with the original drug, and the stabilizer liquid xylitol is added to increase the oil phase ratio and stably encapsulate brassinolide; the selected emulsifier octylphenol polyoxyethylene ether OP-10 has an efficient emulsification effect, diphenylmethane diisocyanate (MDI) is added, the capsule core capsule material ratio is 10:1, and the obtained microcapsule preparation has a high encapsulation rate, a stirring rate of 300r / min, and D90 is between 2.4 and 3.5μm. Dimethoate is used with magnesium aluminum silicate, the suspension rate is high, the fluidity is good, and other indicators are qualified. According to the results of Table 11, the microcapsule suspension prepared by the present invention has stable physical stability and chemical stability, and the encapsulation rate is qualified.

[0158] The test results of the 0.01% brassinolide microcapsule suspension prepared in the present invention are shown in Table 12.

[0159] Table 12 Test results of 0.01% brassinolide microcapsule suspension prepared in Examples 5 to 8

[0160]

[0161]

[0162] In the example of 0.01% brassinolide microcapsule suspension, ethyl acetate is selected as solvent, which is mixed with the original drug, and the stabilizer epoxy linseed oil is added to provide the function of protecting the original drug; the selected emulsifier octylphenol polyoxyethylene ether OP-10 is highly emulsified; isophorone diisocyanate (IPDI) is added, the capsule core capsule material ratio is 8:1, the obtained microcapsule preparation has a high encapsulation rate, a stirring rate of 350r / min, and D90 is between 2.6 and 4.3μm. Solvay's dimethoate is used with an appropriate amount of magnesium aluminum silicate, and the preparation has good fluidity, and other indicators are qualified. According to the results in Table 12, the microcapsule suspension prepared by the present invention has stable physical stability and chemical stability, and a high encapsulation rate.

[0163] The test results of the 0.05% brassinolide microcapsule suspension prepared in the present invention are shown in Table 13.

[0164] Table 13 Test results of 0.05% brassinolide microcapsule suspension prepared in Examples 9 to 12

[0165]

[0166] In the example of 0.05% brassinolide microcapsule suspension, deuterated chloroform is selected as the solvent, which is miscible with the original drug, and the stabilizer liquid xylitol is added to provide the function of protecting the original drug; the selected emulsifier ULTRARIC 5000HM has a proper emulsifying effect, and hexamethylene diisocyanate (HDI) is added, the capsule core capsule material ratio is 10:1, and the obtained microcapsule preparation has a high encapsulation rate, a stirring rate of 300r / min, and D90 is between 3.1 and 4.2μm; hydroxypropyl methylcellulose is used in combination with magnesium aluminum silicate, and the viscosity is slightly higher after hot storage, and other indicators are qualified. According to the results in Table 13, the microcapsule suspension prepared by the present invention has stable physical stability and chemical stability, and a high encapsulation rate.

[0167] The test results of the 20% brassinolide microcapsule suspension prepared in the present invention are shown in Table 14.

[0168] Table 14 Test results of 0.1% brassinolide microcapsule suspension prepared in Examples 13 to 16

[0169]

[0170] In the example of 0.1% brassinolide microcapsule suspension, the solvent is butanol, which is miscible with the original drug, and the stabilizer epoxy linseed oil is added to provide protection for the original drug; the selected emulsifier ULTRARIC 5000HM has an appropriate emulsifying effect, and 4,4-dicyclohexylmethane diisocyanate (HMDI) is added, the capsule core capsule material ratio is 8:1, and the obtained microcapsule preparation has a qualified encapsulation rate, a stirring rate of 300r / min, and a D90 between 3.7 and 4.5μm; hydroxypropyl methylcellulose is used in combination with magnesium aluminum silicate, and relative to Examples 9 to 13, the fluidity after heat storage is good, and other indicators are qualified. According to the results in Table 14, the prepared microcapsule suspension has stable physical and chemical stability and a high encapsulation rate.

[0171] The test results of the 0.15% brassinolide microcapsule suspension prepared in the present invention are shown in Table 15.

[0172] Table 15 Test results of 0.15% brassinolide microcapsule suspension prepared in Examples 17 to 20

[0173]

[0174] In the example of 0.15% brassinolide microcapsule suspension, dimethylformamide is selected as the solvent, which can be well mixed with the original drug, and the stabilizer epoxy soybean oil is added, and the oil stabilizer provides protection for the original drug; the selected Heda auxiliary high-efficiency emulsifier CS-100A, toluene diisocyanate (TDI) is added, the capsule core capsule material ratio is 10:1, and the obtained microcapsule preparation has a qualified encapsulation rate, a stirring rate of 300r / min, and D90 is between 3.1 and 4.1μm; xanthan gum and magnesium aluminum silicate are used, and the fluidity is good after hot storage, and other indicators are qualified. According to the results of Table 15, the microcapsule suspension prepared by the present invention has stable physical stability and chemical stability, and a high encapsulation rate.

[0175] The test results of the 0.2% brassinolide microcapsule suspension prepared in the present invention are shown in Table 16.

[0176] Table 16 Test results of 0.2% brassinolide microcapsule suspension prepared in Examples 21 to 24

[0177]

[0178]

[0179] In the example of 0.2% brassinolide microcapsule suspension, dimethyl sulfoxide is selected as the solvent, which can be well mixed with the original drug, and the stabilizer butanol is added to well inhibit and protect the decomposition of the original drug in the system; the selected block polyether high-efficiency emulsifier ULTRARIC 5000HM, lysine diisocyanate (LDI) is added, the capsule core capsule material ratio is 8:1, and the obtained microcapsule preparation has a qualified encapsulation rate, a stirring rate of 300r / min, and D90 is between 3.0 and 3.9μm; xanthan gum and magnesium aluminum silicate are used, and the fluidity after hot storage is good, and other indicators are qualified. According to the results of Table 16, the microcapsule suspension prepared by the present invention has stable physical stability and chemical stability, and a high encapsulation rate.

[0180] Experimental Example 2 Comparison of sustained release performance

[0181] The product for testing was 0.01% 24-epi-brassinolide microcapsule suspension, which was used to test the sustained-release effect of the CS product, and 0.01% 24-epi-brassinolide soluble solution (Zhengzhou Zhengshi Chemical) was used as a control. The experimental results are shown in Tables 17-18. Figure 2-3 shown.

[0182] When the core material ratio is 10:1, the comparison of CS release rates of capsule materials with different active hydrogen components (SL as the control) is shown in Table 17.

[0183] Table 17 Comparison of CS release rates of different capsule materials (SL control)

[0184]

[0185]

[0186] According to the above Table 17 and Figure 2 As shown in the figure, at the moment when the soluble agent is mixed with the dispersion medium, the active ingredients of the original drug are all free in the dispersion medium, while the release efficiency of the microcapsule suspension increases slowly. The release rate is large in the first few hours because the difference in osmotic pressure between the inside and outside of the microcapsule suspension is too large, and the initial release rate is large. As the original drug in the capsule is released, the difference in osmotic pressure between the inside and outside narrows, and the release rate gradually slows down. There are differences in the initial release rates of different capsule materials because different synthetic materials have different activities and structures, and the size of the gaps in the synthetic capsule wall is also different, so the release rates are also different; in addition, the difference in processing effects also affects the release efficiency, for example, the smaller the processed particle size, the faster the release rate.

[0187] In summary, brassinolide microcapsule suspension has excellent sustained-release effect, which can prolong the effective period, reduce the usage amount, reduce the risk of phytotoxicity, and alleviate environmental pollution.

[0188] When the core material ratio is 8:1, the comparison of CS release rates of capsule materials with different active hydrogen components (SL as the control) is shown in Table 18.

[0189] Table 18 Comparison of CS release rates of different capsule materials (SL control)

[0190]

[0191]

[0192] According to the above Table 18 and Figure 3 As shown in Table 17, with the increase of the core-to-capsule ratio, the release efficiency of brassinolide microcapsules slowed down and decreased significantly compared with Table 17. This is because the proportion of capsule wall material increased, the thickness of the capsule wall and the degree of cross-linking of the capsule wall increased, the structure became more complex, and the gaps narrowed. When the initial osmotic pressure difference was large, the release efficiency difference was not large, but as the osmotic pressure difference decreased, factors such as the thickness of the capsule wall played a prominent role, and the release efficiency gradually slowed down. Compared with the brassinolide soluble solution, the sustained release effect is obvious.

[0193] In summary, compared with traditional brassinolide dosage forms, brassinolide microcapsule suspension has excellent sustained-release effect, which can prolong the effective period, reduce the usage amount, reduce the risk of phytotoxicity, and alleviate environmental pollution.

[0194] 3. Comparative Proportion

[0195] Comparative Example 1 Capsule Material Selection Instructions

[0196] The compounding reaction of isocyanate capsule materials with different functional group numbers and active hydrogen capsule materials is shown in Table 19. During the reaction, according to the core material ratio of 10:1, the isocyanate capsule materials with the same molar concentration, under the same other controllable factors, the insulation temperature is between 50℃ and 60℃, and the insulation time is the same. After the insulation is completed, wait for cooling to room temperature, complete sedimentation, and observe the bottom sediment under a microscope (eyepiece 10 objective lens 40).

[0197] When the precipitate is observed under a microscope, it is evaluated as having a relatively large number of free sac-shaped intact structures, which is considered good; when agglomeration is observed, it is evaluated as the cross-linking reaction being difficult to control; when the precipitate appears to be clumped and not separated, it is evaluated as having a high or excessively high cross-linking strength.

[0198] Table 19 Description of experiments without capsule materials

[0199]

[0200]

[0201] In Table 19, when isopropanol and any isocyanate are capsule materials, no spherical structure can be found in the sediment; when octadecyl isocyanate reacts with any alcohol or amine, no corresponding capsule structure is found in the sediment. In the cross-linking reaction, the number of functional groups of the raw materials needs to be greater than 2; as the number of functional groups increases, the cross-linking strength of the capsule material with the same molar concentration is higher. Using the diisocyanate of the present invention to react with diols or diamines, a better capsule-forming effect can be obtained.

[0202] Comparative Example 2 Reaction Temperature Control

[0203] The comparison of capsule formation reaction at different temperatures is shown in Table 20. During the experiment, if a small amount or a large amount of yellow viscous material appears during the heat preservation process or sinks to the bottom, the cross-linking is too fast or too fast. As the heat preservation is completed and cooled to room temperature, the basic reaction situation can be judged according to the state of the bottom sediment and microscopic observation. After the test is completed and the temperature is lowered, a simple shake is performed. If the sediment does not stick together, it means that the capsule is not formed or the capsule is well formed; if there is adhesion, it means that the cross-linking is excessive; under microscopic observation, it can be divided into moderate cross-linking and excessive cross-linking according to the degree of agglomeration.

[0204] Table 20 Comparison of capsule formation effects at different temperatures

[0205] Temperature range (℃) Cystic state 30～40 No cyst 40～45 The encapsulation is slow, the encapsulation ratio is not high, and the cross-linking speed is slow 45～50 Good encapsulation and moderate cross-linking speed 50～55 Good encapsulation and moderate cross-linking speed 55～60 The encapsulation speed is fast, so the time needs to be controlled to prevent excessive cross-linking 60～65 Fast encapsulation speed and excessive cross-linking

[0206] From the experimental results in Table 20, it can be seen that a better reaction effect can be obtained by reacting at 45-60°C, and the best reaction temperature is 45-55°C.

[0207] Comparative Example 3 Experimental results of different core material ratios

[0208] The experimental results of different core material ratios are shown in Table 21. Using ethylene glycol and isophorone diisocyanate as capsule materials, keeping at 50℃~55℃ for 3h, other controllable factors are the same (including the amount of solvent, stabilizer, emulsifier), the encapsulation rate ≥85% is qualified.

[0209] The degree of cross-linking can be determined based on the adhesion state and proportion of the sediment in the experiment: if there is no adhesion and the sediment is well dispersed, it is appropriate; if particles are observed with the naked eye, it can be determined as the presence of (large) particles, a large number of particles, etc.

[0210] Table 21 Experimental results of different core material ratios

[0211] Core material ratio Evaluation of encapsulation efficiency and cross-linking degree 12:1 The encapsulation rate is not high 10:1 The encapsulation rate is qualified and the cross-linking degree is appropriate 8:1 The encapsulation rate is qualified and the cross-linking degree is appropriate 6:1 The encapsulation rate is qualified, and the degree of cross-linking is high 4:1 The encapsulation rate is qualified, and the degree of cross-linking is high 2:1 The encapsulation rate is qualified, the cross-linking is excessive, there are too many capsule materials, and the particles are large 1:1 The encapsulation rate is qualified, the cross-linking is excessive, there are too many capsule materials, and the particles are large

[0212] It can be seen from Table 21 that when the core material ratio is 10:1 to 8:1, the encapsulation rate is qualified and the overall effect of the reaction is the best.

Claims

1. A method for preparing a microcapsule suspension containing brassinolide, characterized in that: The following steps are involved: (1) dissolving brassinolide and a stabilizer in a solvent, adding isocyanate capsule material and mixing to obtain an oil phase; preparing an aqueous phase using water, an emulsifier, and a defoamer; (2) After the oil phase and the water phase are evenly mixed, the active hydrogen component capsule material is added and mixed, and the microencapsulation semi-finished product is obtained after heating and curing, and then the microencapsulation suspension is obtained after modulation; The isocyanate capsule material is diisocyanate, and the mass ratio of the sum of the brassinolide, stabilizer and solvent to the isocyanate capsule material is (10~8):1; the total mass fraction of the sum of the brassinolide, stabilizer and solvent in the system is 4~5%; the diisocyanate is selected from any one of diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4, 4-dicyclohexylmethane diisocyanate, toluene diisocyanate and lysine diisocyanate; the active hydrogen component capsule material is any one of a diol or a diamine; the diol is any one of ethylene glycol, polyethylene glycol and propylene glycol; the diamine is any one of propylenediamine, tetramethylethylenediamine, tetramethylpropylenediamine and tetrahydroxypropylethylenediamine; the temperature of the heating curing is 45~55°C.

2. The method for preparing a microcapsule suspension containing brassinolide according to claim 1, characterized in that: The brassinolide is any one of 14-hydroxybrassinolide, 24-epibrassinolide, 28-homobrassinolide and propionylbrassinolide; the content of the brassinolide in the microcapsule suspension is 0.001-0.2%.

3. The method for preparing a microcapsule suspension containing brassinolide according to claim 2, characterized in that: The stabilizer is one or more of epoxy linseed oil, epoxy soybean oil, liquid xylitol, and butanol; the mass ratio of the brassinolide to the stabilizer is (0.001-0.2):(2-6).

4. The method for preparing a microcapsule suspension containing brassinolide according to claim 2, characterized in that: The solvent is one or more of butyl acetate, ethyl acetate, deuterated chloroform, butanol, dimethylformamide, and dimethyl sulfoxide; the mass ratio of the brassinolide to the solvent is (0.001-0.2): (2-11).

5. The method for preparing a microcapsule suspension containing brassinolide according to claim 1, characterized in that: The preparation includes mixing the microencapsulated semi-finished product and the processing aid to form the microcapsule suspension; the processing aid is selected from one or more of a thickener, an antifreeze agent, a preservative, and a dispersant.

Images