Preparation And Properties Of Avermectin Loaded Chitosan/Sodium Lignosulfonate Microcapsules

The new biopesticide avermectin was microencapsulated with chitosan and sodium lignosulfonate by complex-coacervation method. The complex reaction conditions were preleminarily selected using orthogonal experimental design, then, the microencapsulation conditions were further elaborated. The optimized microencapsulation conditions were established, i.e.: the viscosity of chitosan was 1500 cps, the concentration of chitosan 0.5%, the concentration of sodium lignosulfonate 2%, Tween80/Span80 ratio 2, the amount of emulsifiers 6mL, the ratio of core to shell 6, reaction temperature 45℃, pH 5.1, stirring speed 300r/min, complex-coacervation time 15min, the amount of crosslinker 4mL, crosslinking time lh, the obtained microcapsules had the drug loading (DL) and encapsulation efficiency (EE) of 12.6%和 92.1 %, respectively.The particle size and morphology of microcapsules were characterized using Laser sizer and SEM. The results showed that chitosan/lignosulfonate microcapsules had the average particle size of 5.80μm, while the avermectin loaded microcapsules fell in the range of 5~27μm, averaged 11.2μm, with narrow distribution. The SEM data indicated that the control microcapsules and avermectin loaded microcapsules had aggregation. FTIR results suggested that no chemical interaction between avermectin and the wall of...