| Use of pesticides is still the most effective and convenient means in controlling agricultural pests.With the rapid development of civil aviation,aircraft spraying has been widely used in recent years,which greatly promoted the development of plants protection mechanization,and saves a lot of labor costs.But the plane spraying pesticide still used traditional formulation products,such as emulsifiable concentrates,wettable powders and suspensions,these formulations do not fully meet the technical requirements of high speed spray air plants.Developping pesticide products for crop protection suited to China’s aviation demand is in urgent,such as ultra low volume agents.Ultra low volume agent suitable for high speed spray aircraft,but in many mountainous geographic conditions and small scale farmer production plant protection application is also subject to certain restrictions,also need to develop some pesticide products using convenient and save labour,such as dosage form suitable for paddy field water direct broadcast products.In view of this we have developed ultra low volume agent and spreading oil tablet research.1.Preparation of ultra low volumeScreening suitable solvent mainly for beta-Cypermethrin blended with emamectin and chlorpyrifos blended with emamectin as an ultra low volume.Firstly,3 kinds of insecticides of drug solubility in 14 solvent(resin based oil,methyl laurate,ethyl laurate,methyl oleate,ethyl oleate,butyl oleate,soybean oil,peanut oil,canola oil,castor oil,glycol,liquid paraffin)was determined.Solubility of emamectin benzoate in ethylene glycol is maximum(106.66 mg/mL).Solubility of chlorpyrifos in ND-45 is maximum(703.4 mg/mL).Solubility of beta-cypermethrin in methyl laurate is maximum(79.84 mg/mL),but there is no significantly differences compared with ND-45(78.33 mg/mL)and ethyl laurate(68.49 mg/mL).The rate of volatile solvents by filter paper method of hanging on the physicochemical properties of Ultra low volume solvent requirement was determined,in addition to resin based outside the oil volatilization rate,other solvent evaporation rate is less than 1.5%.The viscosity of the solvent test by viscometer and resin based oil,methyl laurate,ethyl laurate,methyl oleate,ethyl oleate,butyl oleate are smaller and around 10 mPa·s.The solvents density has no significant difference.However the safety of maize show phytotoxicity on maize of methyl laurate,ethyl laurate are severe,rosin base oils have a mild injury on corn.,and other solvents have a more secure.Comprehensive analysis concluded that emamectin and chlorpyrifos ULV recommended solvent is compound ND-OD-1 with methyl oleate,ethyl oleate or butyl oleate.Beta-cypermethrin and chlorpyrifos ULV recommended solvent is methyl oleate,ethyl oleate,butyl oleate or mixing between the various solvents.2.Preparation of spreading oil tablet.Preliminary filtered oil carrier based on the research,we screened and optimized formulation into the optimization,finalized the molding product formulations,and initially set the new quality standards.For improve the spreading effect on water surface,surfactant has more widely filtered.Determination has including fat alcohol poly oxygen vinyl ether series,and alkyl phenol poly oxygen vinyl ether series,and fatty acids poly oxygen vinyl ether series,and Castor oil poly oxygen vinyl ether series,and benzene b base phenol poly oxygen vinyl ether series,and benzene b base phenol poly oxygen vinyl poly oxygen propylene ether series,and alkyl phenol poly oxygen vinyl ether phosphate ester series and alkyl benzene sulfonic acid calcium total 51 species surfactant of diffusion speed on water surface.Results showed that pesticide emulsifier 602,castor oil ether series EL 20,EL 30,EL 40 and OPEPO can drive the 1 Methyl laurate oil film on water quickly spread,spread over 11 cm/s,and methyl laurate of EL 30 has the fastest speed of 11.55 cm/s.On the based of choose of methyl laurate film has a better effect of single dose,we screened compound surfactant ratio of binary,a total of 33 were determined by a complex combination,obtained proportion of EL 30 with OPEPO 5:3 of methyl laurate the proliferation of film works best.After formulation screening and optimization,we get the optimal Binder,the optimal proportions of fillers and solvent oil is 25%:35%.The final formula for new dosage forms is TC 5%(chlorpyrifos),solvent25%,packing35%,compound surfactants 1.5%,penetrating 1.5%,dispersant6%,disintegrant 10%,Binder 5%and carrier 11%.The quality indexs has determined by China tablets quality detection standard,the results show that original drug(chlorpyrifos)adsorption of carrier can soon release to water from carrier,carrier release chlorpyrifos 80.8%within 24 hours.5%chlorpyrifos spreading oil tablet pH 7.2,decomposition rate of heat storage 7 days later less than 5%,one single tablet disintegrant within 83.6 s,average spreading speed up to 7.6 cm/s,the average spread area is 27.38 m2.For study spreading oil tablets moving law on water surface after apply to water,the dynamic distribution of chlorpyrifos in water,water surface,rice,and soil has been test.Results showed that chlorpyrifos in water and soil is very little,with the passage of time,chlorpyrifos gradually transferring to rice stem from oil slick.Chlorpyrifos is mainly distributed in rice stem(0-2 cm)and water surface within 24 hours,after 24 hours,chlorpyrifos is mainly distributed in the rice stem. |
