Development Of Preparation Technology For Azoxystrobin Emulsions

Fungal infections in plants have poised to cause serious threats to food supply and security over the past decade.Approximately 20 % of global crop yield is being lost to phytopathogenic fungi annually.Many of the conventional formulations of fungicides that are widely used in agricultural applications have several drawbacks including low water solubility,high volatility and high susceptibility to leaching.Research has sought to develop formulations that can circumvent these challenges by advancing a wide range of technologies;nano-controlled delivery systems have been developed for agrochemicals based on biodegradable polymers to maintain optimal pesticide concentrations,protect,and stabilize the pesticides and reduce frequency of use.Azoxystrobin is one of the most commonly used fungicide in agriculture,treating diseases like late blight,rice blast and downy mildew.The main aim of this work was to prepare microemulsion and nanoemulsion formulations of azoxystrobin and investigate their properties,efficiency and efficacy.Additionally sustained release gel formulations of azoxystrobin were prepared using ethylicin as the model drug.In microemulsion preparation,an analysis of the interaction of four factors that are key to the formation of the azoxystrobin microemulsion was done.These factors include emulsifiers,solvents,dispersants and additives.The microemulsion with emulsifiable properties and remarkable efficiency was produced through orthogonal experiments.In the preparation of the nanoemulsion formulation,factors that promote the formation of the smallest particle sizes were investigated through independent and combination assays.The least particle size of the nanoemulsion(around 190 nm)was obtained through combination of highest concentrations of water,solvent and surfactant.Characterization of the nanoemulsion was done through scanning electron microscope and zeta potential determination.The particles were observed to be small and spherical in structure(about 60nm)with a surface charge ranging from-0.984 to+0.3486 m V.Efficacy tests revealed an increased activity of azoxystrobin in nanoemulsion against the growth of Alternaria alternate Keislar and a reduced sensitivity against Aspergillus niger.Screening of thermal sensitive coating materials was done using ethylicin as the model drug.Sustained release gel formulations of azoxystrobinwere prepared.A sustained release of azoxystrobin was observed from4℃ to 40℃.An increased activity against the growth of Aspergillus niger was observed on performing the agar-disk diffusion assay.