Preparation Of ButachlorMicrocapsule Based On The Biodegradable Material Carrier By Solvent Evaporation Method

Development of new dosage form is becoming a new research hot spot, because new compounds used as pesticide screened more and more difficutly. Traditional dosage forms, such as Emulsifiable Concentrate (EC), Wettable Powder (WP), has not adapted to the current requirements of green plant protection. Butachlor is a widely-used herbicides. The main forms of registration is EC. Annual consumption is high with high environment pressure made. The improvement of residual activity and utilization rate of Butachlor has been payed widely attention. Poly(butylene succinate-co-butylene adipate) and Poly(propylene carbonate) are synthetic polymer materials with favoureble biodegradability and will be used widely in the field of controlled release formulations of pesticide. It is an effective way to reduce the usage and the improvement of residual activity and utilization rate of the biodegradable microcapsules of Butachlor.Thus, in this paper, with poly (propylene carbonate) (PPC) and poly (butylene succinate-co-butylene adipate acid) (PBSA) as wall material, the emulsion solvent evaporation method of butachlor microcapsule was preparated by the emulsion solvent evaporation method and realize to controlled release. With the preparation and characterization of butachlor microcapsule as the research focus, the main results csrried out were as follows:PVA-1788 was screened from a variety of water soluble polymer materials and used as emulsion dispersant in emulsion solvent evaporation method. Variance-method and range-method are used to study mass concerntration of PVA-1788, weight ratio of core material and wall material, volumn ratio of oil phase and water phase, sheer ratio of these four factors which impact on microcapsule size in the method. The result showed that sheer ratio>mass concerntration of PVA-1788>weight ratio of core material and wall material>volumn ratio of oil phase and water phase.With PBSA as the capsule material, PBSA-butachlor microcapsules were prepared by emulsion solvent volatilization method. Performance of the microcapsules were characterized. The results showed that PBSA-Butachlor microcapsule'sphere was regular, particle size in 5.63 ?m and uniform, drug loading was 13.92% and encapsulation rate was 81.41%, with good release performance. After 28 d, the cumulative release rate reached 85.54%. PBSA with superior performance is likely to become a common carrier of pesticide.With PPC modificated by polylactic acid (PLA) as carrier, PLA/PPC-Butachlor microcapsules were prepared by emulsion solvent evaporation method. The effect of preparation conditions on the particle size of the microcapsules was investigated. Performance of the microcapsules have been characterized. The results showed that when the PLA/PPC quality ratio of 20/80, better microcapsule could be prepared. When sheer ratio was 14 000 r/min, mass concerntration of PVA-1788 used as emulsifying dispersant in the water phase was 1.25%, weight ratio of PLA/PPC blend material and butachlor the oil phase was 2:1, particle size was ideal. The particle size of the microcapsules was 4.86 ?m, drug loadings was 14.36%, the encapsulation rate of 84.95%, with a good slow-release performance. After 28 d, the cumulative release rate reached 83.46%.