溶剂蒸发法制备丙硫菌唑微囊及其性能研究

doi:10.3864/j.issn.0578-1752.2021.04.008

摘要/Abstract

摘要：

【目的】以生物可降解材料聚(3-羟基丁酸酯-co-4-羟基丁酸酯）（P(3HB-co-4HB)）为壁材制备丙硫菌唑微囊,研究制备工艺对微囊粒径、载药量及包封率的影响,筛选出分散性好、粒径较小、载药量高的配方,并对其释放动力学、光降解、对花生白绢病菌（Sclerotium rolfsii）室内生物活性等性能进行初步研究和表征,为提高丙硫菌唑在环境中的稳定性及利用率提供理论指导和技术支撑。【方法】采用溶剂蒸发法制备丙硫菌唑微囊,通过单因素试验探究芯壁材质量比、油水体积比、乳化剂质量分数和剪切速率对微囊粒径、载药量和包封率的影响;以载药量与粒径为关键技术指标,通过L₉(3⁴)正交试验筛选出最优制备工艺参数,并对正交试验结果进行验证;通过扫描电镜（SEM）、傅里叶红外光谱（FTIR）、高效液相色谱（HPLC）和室内毒力测定对微囊的外观形貌、释放性能、光稳定性能以及对花生白绢病菌的室内生物活性进行研究。【结果】芯壁材质量比对微囊的载药量有显著影响,随着芯材质量的增大,载药量逐渐增大;油水体积比、PVA质量分数、剪切速率对微囊粒径具有显著影响,随着剪切速率与PVA质量分数的增大,微囊粒径逐渐减小,油水体积比对微囊形态及分散性影响较大。试验中各因素对微囊包封率的影响并不显著。通过L₉(3⁴)正交试验配方优化获得最佳制备工艺：芯壁材质量比1﹕5,油水体积比1﹕5,PVA质量分数2%和剪切速率12 000 r/min。在最佳制备工艺条件下制备了粒径（D₅₀）为3.32 μm、跨距为2.82,分散性良好的球形丙硫菌唑微囊,载药量为15.52%,包封率为80.24%。该微囊具有较好的缓释性能,其释放动力学符合Fick扩散规律,呈现先“突释”后“缓释”两个过程。与原药相比,丙硫菌唑微囊在水溶液中的光稳定性增强,光解半衰期延长了一倍。菌丝生长抑制试验表明其对花生白绢病菌的抑制活性与原药相当。【结论】以生物可降解材料P(3HB-co-4HB)为载体制备丙硫菌唑微囊,不同制备工艺影响微囊的载药量、分散性和粒径大小,其缓释及光稳定性能对减少农药施用量、提高农药利用率具有重要意义。丙硫菌唑微囊在花生白绢病的防治方面具有良好的应用前景。

关键词: 丙硫菌唑, 聚羟基丁酸酯, 微囊, 制备工艺, 控制释放, 花生白绢病菌

Abstract:

【Objective】The biodegradable material poly (3-hydroxybutyrate-co-4-hydroxybutyrate) (P (3HB-co-4HB)) was used as the wall material to prepare prothioconazole microcapsules. The effect of preparation process on the microcapsule size, pesticide loading and encapsulation efficiency was optimized. The microcapsules with good dispersion, small particle size, and high pesticide loading were screened out, and the preliminary researches on the release kinetics, photodegradation, and indoor biological activity on Sclerotium rolfsii were carried out. The purpose of this study is to provide a theoretical basis and technical support for improving the stability and utilization efficiency of prothioconazole in the environment.【Method】The solvent evaporation method was used to prepare prothioconazole microcapsules, and the effects of the mass ratio of core to wall material, volume ratio of oil to water, mass fraction of emulsifier and shearing speed on the particle size, pesticide loading and encapsulation efficiency of the microcapsules were investigated through a single factor test. Taking pesticide loading and particle size as the key technical indicators, the optimal preparation parameters were screened out through the L₉(3⁴) orthogonal test, which was further verified. The morphological and structural features, release performance and photodegradability of the microcapsules were determined by scanning electron microscope (SEM), fourier transform infrared (FTIR) spectrometer, and high performance liquid chromatography (HPLC). The toxicity of prothioconazole microcapsules on S. rolfsii was investigated by indoor bioassay.【Result】The mass ratio of core to wall material had a significant effect on the pesticide loading capacity of the microcapsules. As the ratio of core material increased, the loading capacity gradually increased. The volume ratio of oil to water, PVA mass fraction, and shearing speed had significant effects on the microcapsule particle size. As the shearing speed and PVA mass fraction increased, the microcapsule particle size gradually decreased. The volume ratio of oil to water had a great influence on the morphology and dispersion of microcapsules, and the influence of various factors on the encapsulation efficiency of the microcapsules was not significant. The optimal preparation parameters obtained through the L₉(3⁴) orthogonal test was as follows: the mass ratio of core to wall material of 1﹕5, volume ratio of oil to water of 1﹕5, PVA mass fraction of 2%, and shearing speed of 12 000 r/min. Under the optimal preparation process, spherical prothioconazole microcapsules with a particle size (D₅₀) of 3.32 μm and a span of 2.82 were prepared with a loading content of 15.52% and an encapsulation efficiency of 80.24%. Compared with prothioconazole technical material, the microcapsules had better sustained-release performance, and the release kinetics conformed to Fick’s diffusion law, presenting two processes of “burst release” followed by “sustained release”. The photostability of prothioconazole in the microcapsules in aqueous solution was enhanced, and the half-life of photolysis was doubled. The mycelial growth rate inhibition result showed that the fungicidal activity of prothioconazole microcapsules against S. rolfsii was equivalent to that of prothioconazole technical material.【Conclusion】Prothioconazole microcapsules with biodegradable material P (3HB-co-4HB) as a carrier were prepared, and different preparation processes affect the pesticide loading, dispersion state and particle size of microcapsules. The slow and sustained release and photostability are of great significance for reducing the amount of pesticide applied and improving the utilization efficiency of pesticide, which has potential application in control of peanut southern blight.

Key words: prothioconazole, polyhydroxybutyrate, microcapsule, preparation process, controlled release, Sclerotium rolfsii

陈歌,曹立冬,许春丽,赵鹏跃,曹冲,李凤敏,黄啟良. 溶剂蒸发法制备丙硫菌唑微囊及其性能研究[J]. 中国农业科学, 2021, 54(4): 754-767.

CHEN Ge,CAO LiDong,XU ChunLi,ZHAO PengYue,CAO Chong,LI FengMin,HUANG QiLiang. Performance Study of Prothioconazole Microcapsules Prepared by Solvent Evaporation Method[J]. Scientia Agricultura Sinica, 2021, 54(4): 754-767.

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https://www.chinaagrisci.com/CN/Y2021/V54/I4/754

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因素水平 Factor level	1	2	3	4
芯壁材质量比 Mass ratio of core to wall material	1﹕5	1﹕10	1﹕20
油水体积比 Volume ratio of oil to water	1﹕5	1﹕10	1﹕15	1﹕20
PVA质量分数 Mass fraction of PVA (%)	0.5	1	1.5	2
剪切速率 Shearing speed (r/min)	4000	8000	12000

水平 Level	因素Factor
水平 Level	A	B	C	D
1	1﹕15	1﹕15	0.5%	4000
2	1﹕10	1﹕10	1%	8000
3	1﹕5	1﹕5	2%	12000

PVA质量分数 Mass fraction of PVA (%)	载药量 Loading content (%)	包封率 Encapsulation efficiency (%)	粒径 D₅₀ (μm)	跨距 Span
0.5	15.58±0.83a	77.47±5.79a	4.61±0.06a	3.70b
1	15.69±0.21a	78.90±1.47a	3.46±0.06b	4.26a
1.5	15.67±0.34a	80.47±4.07a	3.21±0.06c	3.69b
2	15.12±1.69a	78.70±3.04a	2.55±0.04d	2.91c

芯壁质量比 Mass ratio of core to wall	载药量 Loading content (%)	包封率 Encapsulation efficiency (%)	粒径 D₅₀(μm)	跨距 Span
1﹕5	15.31±2.28a	77.04±7.26a	3.46±0.06b	4.26a
1﹕10	7.69±0.98b	75.99±2.10a	3.47±0.05b	4.08b
1﹕20	4.66±0.12c	71.72±2.92a	4.33±0.08a	4.22a

油水体积比 Volume ratio of oil to water	载药量 Loading content (%)	包封率 Encapsulation efficiency (%)	粒径 D₅₀(μm)	跨距 Span
1﹕5	15.38±1.34a	76.98±6.36a	3.46±0.06a	4.26c
1﹕10	15.35±0.34a	67.07±6.39a	2.65±0.01d	4.52b
1﹕15	14.82±2.36a	68.08±6.53a	3.13±0.03b	4.29c
1﹕20	14.88±1.09a	74.26±4.34a	2.90±0.08c	5.38a