Research On New Paraquat Solid Preparations

Paraquat was abroad using among non-selective herbicide which had contact toxicity and absorpton action,in a manner.Paraquat had been recogniazed widely for the advantages of high efficiency,broad spectrum,long effective period,residual period short and deactivation in the soil environment.However,hige oral poisoning mortality limited its development.No.1745 bulletin announced that the production,sale and use of paraquat agent were gradually replaced in China.The development of a new form of alternative paraquat was our important subject which need to be solved urgently.Through a series of experiments,we confirmed a new dosage form—16%paraquat soluble power,which had good weeding effect,no irritation and broad application.Electron spectroscopy was used to determine the paraquat solution.It was first discovered that the solution of raw paraquat existed obvious molecular association.In the pure water conditon,two molecular accociation reaction of paraquat was observed with concentration between 10.89 ppm and 15.38 ppm,which acted in a dose-dependent manner.Foue molecular association reaction of paraquat occurred when the concentration wan 16.48 ppm to 21.71 ppm.Computer-aided drug design software CAChe was used to simulate and calculate paraquat molecule.It indicated that plane paraquat molecules were easily created molecular association.Besides,with the increase of degree of association reaction,the energy was lower and the system was more stable.UV-Vis spectroscopy was used to determine the inclusion constant of paraquat and ?-cyclodextrin.The inclusion contant was farily large,indicated that ?-cyclodextrin could improve the association reaction of paraquat.Further analysis showed that the commercial aqueous solution which added surfactant or solution of the inclusion complex displayed an obviously diminished association phenimennon,which wad caused by the addition of surfactant or cyclodextrin.To optimize the preparation technique,we set out the experiment from two sides—choice of packing and accessory ingredient.Through the experiment of influence on the fomability,we found that adding equal quantity paraquat and?-cyclodextrin had good fomability.Adding water soluble starch or lactose can play a good resistance to moisture absorption effect.Surface tension was determined to choice accessory ingredient.It showed that I,S,N compound had optimization of the surface activity.The rabbit acute skin irritaiton test and eye irritation test showed that paraquat soluble powder(No.4)had no irritation.Weed control test result indicated that the effect of the paraquat soluble powder was the same as the paraquat agent.Trough optimizing the preparation technique,we developed a new preparation of paraquat soluble powder,which had good weeding effect and no irritation.As a paraquat alternative product,the new produce had broad market development.