Research On Preparation And Properties Of Nanoparticle Drug Delivery Systems For Avermectins

Pesticide is essential for farming, but it is criticized to be harmful to environment and food. Therefore the rational choice and proper use of pesticide are the most important issue in agriculture. Nowadays, because of the restrictive use of many chemical pesticides, biopesticides commence to play an important part in modern agriculture. The exploitation and application of biopesticides have been the ultimate means to lessen environmental pollution and ensure health of people. One of the most yield pesticides is Avermectics in the world, emulsifiable concentrates and dusts of Avermectics have been used for vegetables, economic crops, etc. but there is no better form of it. The Tappearance ofnanotechnology provided a good idea for this question. Amorphous nanosilica and the low molecular weight CTS are novel nanobiopesticides to be used controlling insects, bacteria, algae, viruses for plants and stockbreeding. Based on above mentioned research findings in agriculture and other fields, and the other findings of nanomaterials, we firstly conducted a study on the amorphous modified-nanosilica and low molecular weight CTS as carriers for Avermectics.Nanosilica is synthesized by sol-gel method, and its properties had been analyzed by the means of BET, SEM, TEM, XRD, IR, etc. the products take on white powder, the BET and BJH adsorption average pore diameter under the the different quantity of surfactant are different, the size of nanoparticles are about 50nm, roundness, amorphism, collective, After modified by silicone coupling agent nanosilica dispersed better than before.We preparated nanosilica-Avermectics system with nanosilica and modified nanosilica, the size of nanosilica-Avermectics system is about 50nm., Chemical reaction did not happen between Avermectics and nanosilica by IR except for thin interactions, Nanosilica absorbed the amount of Avermectics increased with the time until balance; Release profile of free avermectins was straight and abrupt in 30% ethanol, there was not obvious control realease line. Nanosilica-Avermectics system and modified nanosilica-Avermectics system released Avermectics quickly first, then slowly and continued for several days.The low molecular weight CTS was obtained by H2O2 decomposed method, 1%H2O2, 60℃,1h are the finest conditions. The structure of low molecular weight CTS is the same as the high molecular weight CTS as confirmed by IR. Deacetylation result of the low molecular weight CTS was 96.07% and the viscosity-average molecular weight of water-solubility CTS was 5.20×104D.The low molecular weight CTS nanoparticles system is prepared by emulsification-connection method. The size of nanoparticles which were synthesized by the high molecular weight CTS was larger than those which were synthesized by the low molecular weight CTS. Several conditions were reviewed, the results showed that the size of more than 80% particles were less than 100nm in this system, drug loadings and recovery rates were all more than 30%. The system could resist UV ray and had well dispersion, stability and suitable to different water.These results showed that nanosilica--Avermectics system and CTS nanomecidine carrier system were controlled realeased and UV ray resisted; Both of them could be used as environmental friendly materials for preparation of novel Avermectics forms.