Study On Preparation And Properties Of New Dry Flowable Formulations

Dry Flowable(DF)is a new type of pesticide dosage form with high efficiency,little harm and excellent performance.It has excellent dispersibility and suspension stability.Dry suspension agents are mainly prepared by wet method and dry method.In this paper,two formulations of dry suspension agents were prepared by wet grinding and spray drying,and their properties were preliminarily studied.Wet grinding technology is the first step to prepare dry suspension agent,the process is similar to the preparation process of suspension concentrate,that is,the suspension system is prepared by wet grinding,but the difference with suspension concentrate is that the suspension concentrate on the system of suspension stability and storage stability requirements are very high,so suspension concentrate usually need to add some other auxiliaries to improve these problems,and dry suspension agents does not need to add additional these auxiliaries.The second step in the preparation of dry suspension agent is spray drying to granule,this process needs to experience high temperature,and pesticide active agents is heat sensitive product,so it is necessary to add appropriate amount of dispersant with good heat resistance to prevent the pesticide form agglomerating in the high temperature drying process.In this study,two kinds of dry suspension agents,42% pyrazolium ester and 40% nitrile pyrazolium were prepared.The main contents and consequence of the study are shown below:1、The first is to determine the type of auxiliaries,the main way to determine is the flow point method;2、Then,according to the performance changes of dry suspension agent samples after thermal storage,further screening of additives is carried out;furthermore,the composition ratio of dispersant was determined by Zeta potential,suspension rate and particle size variation of the system;Then the optimum amount of wetting agent was determined through the comprehensive influence of wetting time and suspension rate on the system performance.3、Through particle size,disintegration,suspension rate and heat storage stability and other performance tests,the relatively good formula is showed : pyraclostrobin was 6%,cymoxanil was 36%,SD-816 was 6%,WL was 5%,defoaming agent was 1%,603 w was 42%,and finally it was supplemented to 100% with deionized water,and the results of the disintegration time is 35 s,the contact angle is 60°and the suspension rate is 95%..4、Through the previous work,the dispersant 603 w with better application effect was tried to be applied into the active drug nitrile mycorazole,and the formulation of dry suspension agent for this active drug was developed,and the relatively optimal formulation was finally determined: myclobutanil was 40%,603 w was 6%,wet-88 was 5%,urea was 5%,defoaming agent was 1%,and finally supplemented with deionized water to 100%,and the results of the disintegration time is 28 s,the contact angle is 58°and the suspension rate is 94.58%.