氯代水杨胺缓释颗粒剂的制备及其杀螺效果

Preparation and Molluscicidal Effect of Chlorosalicylicamide Sustained-release Granules

目的研究5%和10%氯代水杨胺缓释颗粒剂(LDS-SRG)的制备方法及其杀螺效果。方法筛选载体、表面活性剂、黏合剂、消泡剂、润滑剂,制备5%和10%的LDS-SRG。对其堆密度、水分含量、休止角、临界相对湿度、热贮稳定性和释放速度进行测定。在实验室条件下以剂量1.6 g/m^2(喷撒法)测试LDS-SRG的杀螺效果,设置50%氯硝柳胺乙醇胺盐可湿性粉剂(WPN)1.0 g/m^2药物对照组和空白对照组(脱氯水),分别计算施药后3、7、14 d钉螺的死亡率。结果制备的5%和10%的LDS-SRG均为红褐色,流动性良好;其堆密度分别为0.655 g/ml和0.594 g/ml;水分含量分别为1.15%和1.28%;休止角分别为39.8°和39.7°;临界相对湿度分别为64.98%和61.63%;热贮稳定性均良好。释放曲线表明,5%、10%的LDS-SRG第1~9天均平稳释放,5%LDS-SRG释放速度大于10%LDS-SRG;药物快速释放分别出现在第10天和第15天;并分别在第14天和第20天逐步趋于平稳。实验室喷撒结果显示,5%LDS-SRG 1.6 g/m2施药后7 d、10%LDS-SRG 1.6 g/m2施药后14 d,钉螺的死亡率均>95%,且均高于50%WPN 1.0 g/m^2对照组,差异有统计学意义(P<0.05)。结论 5%和10%的LDSSRG经实验室测试达到缓释效果,采用喷撒法灭螺,均达到农药登记用杀钉螺剂药效评价指标要求。

Objective To prepare the 5% and 10% chlorosalicylicamide（quinoid-2’, 5-dichloro-4’-nitrosalicylanilide from niclosamide） sustained-release granules （LDS-SRG） and evaluate their molluscicidal effect. Methods The 5% and 10% LDS-SRG were prepared with screened carriers, surfactants, adhesives, defoamers and lubricants. Their bulk density, water content, repose angle, critical relative humidity, thermal stability and release rate were determined. Spraying method was used to test the molluscicidal effect of LDS-SRG at 1.6 g/m2. Meanwhile, 50% wettable powder of niclosamide ethanolamine salt（WPN） was applied as the positive control at 1.0 g/m2, and dechlorinated water was used as the blank control. The mortality of snails was calculated on days 3, 7 and 14 after administration. Results The 5% and 10% LDS-SRG were red brown in color, showed good fluidity, and had bulk density of 0.655 g/ml and 0.594 g/ml, moisture content of 1.15% and 1.28%, repose angle of 39.8° and 39.7°, and critical relative humidity of 64.98% and 61.63%, respectively. Moreover, both showed good thermal stability. The release curve was stable for both 5% and 10% LDS-SRG during day 1 to day 9, and faster release for 5% LDS-SRG than for 10% LDS-SRG. The burst release occurred on days 10 and 15, and the steady release occurred from days 14 and 20 for 5% and 10% LDS-SRG respectively. The snail mortality on day 7 after 5% LDS-SRG 1.6 g/m2 administration and on day 14 after 10% LDS-SRG 1.6 g/m2 administration was both higher than 95%, and higher than that of the 50% WPN 1.0 g/m2 control（P〈0.05）. Conclusion The 5% and 10% LDS-SRG show sustained-release potential and satisfactory molluscicidal effect by spraying, reaching the evaluation standard for molluscicidal agents.