羧甲基壳聚糖-蓖麻油基聚氨酯农药缓释微球的制备及性能

Preparation and properties of carboxymethyl chitosan-castor oil-based polyurethane pesticide sustained-release microspheres

摘要:

以羧甲基壳聚糖（CMCS）、蓖麻油（CO）和异佛尔酮二异氰酸酯（IPDI）为原料，自乳化法制备了羧甲基壳聚糖-蓖麻油基聚氨酯微球（CO-CMCS-PU），通过分子自组装法负载阿维菌素（AVM）得到载药微球（CO-CMCS-PU@AVM）。采用FTIR、1HNMR、SEM、TGA等对产品结构及形貌进行表征，并探究了不同药量载药微球的包封率、缓释性能、抗紫外性能、叶面接触角和黏附性能。结果表明，相比AVM分散液，紫外照射后载药微球中AVM的保留率提高到43%，说明CO-CMCS-PU载体的抗紫外性能良好；载药微球比AVM分散液在黄瓜叶面上的接触角降低了20%以上，滞留量提高了40%以上，说明其在叶面上有较好的黏附性和润湿性；载药微球包封率可达80%以上，具有良好的缓释和pH响应释放性能，释药行为符合First-order动力学模型，药物释放受Fickian扩散控制。

关键词:羧甲基壳聚糖;蓖麻油;聚氨酯;缓释;pH响应

Abstract:

Carboxymethyl chitosan-castor oil-based polyurethane microspheres (CO-CMCS-PU) were prepared from carboxymethyl chitosan (CMCS), castor oil (CO) and isophorone diisocyanate (IPDI) by self-emulsification, and drug-loaded microspheres (CO-CMCS-PU@AVM) were obtained by loading avermectin (AVM) by molecular self-assembly. The structure and morphology of the product were characterized by FTIR, 1HNMR, SEM and TGA, and the encapsulation efficiency, slow-release performance, anti-ultraviolet performance, leaf contact angle and adhesion performance of drug-loaded microspheres with different doses were explored. The results showed that compared with AVM dispersion, the retention rate of AVM in drug-loaded microspheres increased to 43% after ultraviolet irradiation, which indicated that CO-CMCS-PU carrier had good ultraviolet resistance. Compared with AVM dispersion, the contact angle of drug-loaded microspheres on cucumber leaves decreased by more than 20%, and the retention capacity increased by more than 40%, which indicated that they had good adhesion and wettability on cucumber leaves. The encapsulation efficiency of drug-loaded microspheres can reach more than 80%, which has good slow-release and pH-responsive release performance. The drug release behavior conforms to the First-order kinetic model, and the drug release is controlled by Fickian diffusion.

Key words:carboxymethyl chitosan; castor oil; polyurethane; sustained release; pH response