|
|
- 2015
15%甲霜灵微胶囊缓释剂制备对烟草黑胫病的防治效果
|
Abstract:
为明确15%甲霜灵微胶囊缓释剂配方及对烟草黑胫病的防治效果,采用原位聚合法制备并优化工艺,对获得的微胶囊进行释放规律研究及评价,并通过盆栽试验确定其防治效果.结果显示,微胶囊缓释剂最佳配方为(用质量分数表示):15%甲霜灵原药、27%二甲苯、2.5%农乳0203、2%氯化铵、4%乙二醇、0.2%黄原胶、2%NNO、47.3%水;制备优化工艺为:芯壁比例1:1、搅拌速度400 r/min、调酸时间2 h、pH 4.5.所获得微胶囊制剂表面光滑致密凹陷,大小均一,平均粒径12.93 μm,包覆率93.58%.制剂有效成分在水相中缓慢释放,0~24 h为初期释放阶段,符合一级动力学方程,R2为0.9115,累计释放量达29.52%;24~360 h为匀速释放阶段,符合零级释放动力学方程,R2为0.9945,累计释放量为29.52%~93.22%;360 h后趋于稳定.施用所制备的15%甲霜灵微胶囊21 d后对烟草黑胫病的盆栽防治效果为82.2%,高于25%甲霜灵可湿性粉剂(75.7%).表明制备的15%甲霜灵微胶囊具有良好的缓释性,对烟草黑胫病有较好的防治效果.
In order to clarify the control efficacy of 15% sustained released metalaxyl microcapsules to tobacco black shank, its release rule was studied by using the optimized in-situ polymerization. The effect on black shank was evaluated through greenhouse pot experiment. The optimum formula of metalaxyl microcapsules was as follows: 15% metalaxyl ingredient, 27% xylene, 2.5% 0203, 2% ammonium chloride, 4% ethylene glycol, 0.2% xanthan gum, 2% NNO, and 47.3% water. The preparation parameters were: a core wall ratio of 1:1, a stirring rate of 400 r/min, 2 h of acid time, and a pH value of 4.5. The obtained microcapsules had smooth surface, uniform particle size with an average diameter of 12.93 μm and a cover rate of 93.58%. The effective components of metalaxyl microcapsules were slowly released in water. In line with the first-order kinetics equation, the period of 0-24 h was the initial release phase, with a released amount of 29.52%. In accordance with the zero-order release kinetics equation, it was released at a constant speed during the period of 24-360 h, with an amount of 29.52%-93.22%. The release became stable after 360 h. The control efficiency of the microcapsules was 82.2% to black shank 21 days after application, which was higher than 25% metalaxyl WP (75.7%). These results indicated that the 15% sustained released metalaxyl microcapsules had a good quality of slow releasing, and could effectively control tobacco black shank.
