Preparation Of Spinosad-Chlorpyrifos Microsphere And Its Characteristics Analysis

Based on the bioassay techniques in laboratory. the best ratio of spinosad and chlorpyrifos was screened with the the interactive method.The results showed that a mass ratio of the active ingredient 1:20 spinosad to chlorpyrifos was optimal and that this blend had synergic action and a co-toxicity coefficient(CTC) 160.24. afterwards. spinosad-chlorpyrifos microsphere(SCM) was prepared with biodegradable polylactic acid (PLA) as wall materials and A certain quality spinosad-chlorpyrifos Technical composition mixed in a proportion as core materials by a Modified Solvent Evaporation/Extraction Method.The effects of volume ratio of O/W phase、stirring velocity、emulsifie、mass concentration of PLA、mass ratio of core materials and wall materials and on the characteristics of microsphere were investigated. In the optimal formulation, the volume ratio of oil phase and water phase was 1:20.the Arab glue was used as emulsifier with the mass concentration of 17.5 g/L, the stirring velocity was 4000 r/min,the mass ratio of core materials and wall materials was 1:3,Emulsifying time was 36 S,the reaction temperature was at 30℃ and the mass concentration of PLA was 120mg/mLThe shape and surface morphology of spinosad-chlorpyrifos microspheres(SCM) were scaned by using,scanning electron microscope(SEM),the result shows that the SCM, which were prepared in the optimum formulations and process conditions are round beads which have relatively smooth surface. In addition, the characteristics of SCM were evaluated by using differential scanning calorimetry (DSC)and HPLC. the result shows that core materials and wall materials are formed drug-loaded micropheres via chemical bonds indeed.and Compared with spinosad and chlorpyrifos Technical combination, the drug-loaded micropheres displayed a nice photostability.The spinosad-chlorpyrifos microspheres(SCM) were prepared with better technological parameter. Besides, the effect of wetting agent and dispersing agent, thickener, and the anti,-freeze agent to microspheres SC were investigated. The results shows that the best quality of the spinosad-chlorpyrifos microspheres SC was prepared with the prescription as followed:wetting and dispersing agent is a mixture of MORWET-EFW and TERWET1004 whose ratio is 3:2 with an total amount of 50 mg/mL:the thickening agent is 30 mg/mL of Magnesium Aluminum Silicate and 30 mg/mL of ethylene glycol is used as antifreeze respectively.In addition,the field efficacy of the spinosad-chlorpyrifos microspheres SC was evaluated on plutella xylostella. Compared with 525g/L spinosad-chlorpyrifos EC,the result shows that after 7 days,the control effect of two drugs displayed no signifiCant difference.Compared with Commercially available single-dose drug, the result shows that after 7 days,the control effect of two drugs displayed significant difference.