阿维菌素包合物的红外光谱研究

Study on the Inclusion Compound of Avermectin by Infrared Spectroscopy

依据β-环糊精的分子空腔容纳性质,利用饱和水溶液法制备出阿维菌素-β-环糊精包合物,利用高效液相色谱法测定其包封率。结合红外光谱谱图说明了阿维菌素-β-环糊精包合物的形成;分析了阿维菌素光解所产生的化学结构变化;研究了所形成的包合物增强阿维菌素化学结构光稳定性的效应。结果表明:阿维菌素-β-环糊精包合物的包封率为40.5%;从红外光谱谱图分析,说明阿维菌素-β-环糊精包合物形成了分子间氢键,组合效应与其物理混合物有区别。阿维菌素B1a分子大环内酯结构可以被光分解破坏,分解后大环内酯结构中的C—O—C结构红外伸缩振动峰消失,内酯键发生明显断裂。形成阿维菌素-β-环糊精包合物后,β-环糊精起包合作用的分子位点覆盖了阿维菌素B1a分子大环内酯结构,为阿维菌素B1a分子大环内酯结构中的C—O—C结构提供良好的避光保护作用,提高了阿维菌素B1a分子的光稳定性。本实验的创新之处在于对所制备的阿维菌素-β-环糊精包合物的结构和特性从红外光谱角度进行了分析,此类包合物可望作为理想的阿维菌素保护型控释制剂中间体。

This study was designed to investigate the formation and effect of inclusion complex of Avermectin-β-cyclodextrin based on the accommodation property of β-cyclodextrin＆#39;s molecular cavity .The inclusion complex of Avermectin-β-cyclodextrin was prepared using saturated solution method and high performance liquid chromatography （HPLC） was employed to determine its entraping efficiency .The formation of Avermectin-β-cyclodextrin inclusion complex was also demonstrated by infrared spec-troscopy（IR） .The change of chemical structure produced by photocatalysis of Abamectin was analyzed and the effect of inclusion complex to strengthen the photolysis stability of Abamectin-β-chemical structure was studied .The results show that the entra-ping efficiency of the inclusion complex was 40.5% .The IR analysis presents that the intermolecular hydrogen bond was formed in the Avermectin-β-cyclodextrin inclusion complex ,indicating the composition effect was different from physical mixture .The lactones structure of Avermectin B1a can be photodecomposed and disrupted .After decomposition ,the infrared stretching vibra-tion peak of C-O-C structure disappeared and the lactone bond was significantly broken .The lactones structure of avermectin B1a was covered by the inclusion molecular loci in β-cyclodextrin after the formation of avermectin-β-cyclodextrin inclusion com-plex ,providing a good photophobic protection for C -O-C structure in the macrocyclic lactone structure of avermectin B 1a and improving the photostability of avermectin B1a molecule .The innovation of this study is that the structure and the characters of the prepared avermectin-β-cyclodextrin inclusion complex were analyzed using spectrum methods .This inclusion complex is ex-pected to be the ideal intermediate in the construction of protective controlled release formulation of avermectin .