Preparation of Pyrethrins Microcapsule by β-cyclodextrin and Application

Abstract:

Natural pyrethrins was encapsulated in hollow hydrophobic part of β-cyclodextrin to protect it against natural degradation. The encapsulation efficiency and drug content of the pyrethrins microcapsule prepared were 92.15% and 8.5%, respectively, and the particle size ranged from 1 to 17 μm. It was demonstrated that the pyrethrins microcapsule had better thermal stability and slow-release capability than liquid pyrethrins. Its slow-release kinetics could be described as the first-order model. The storage stability of pyrethrins was improved after encapsulation. Results showed that the drug content decreased within 20% after 5 months at 4℃. Under natural conditions, microcapsules could also prolong the storage duration of pyrethrins by 1~1.5 times. The pyrethrins microcapsule in this study had high insecticidal activity against Culex pipiens pallens, Aedes albopictus, Chilo suppressalis, aphids and Myxodes armyworm, indicating that it was a promising pesticide for the control of pests.

Key words:natural pesticide; pyrethrins; β-cyclodextrin; microcapsule; stability