Pesticidal dry powder formulation enriched in azadirachtin up to 88% an emulsifiable concentrate enriched up to 30% of azadirachtin and a process for preparing such formulation and concentrate from neem seed/kernel

Abstract

The invention relates to a preparation of azadirachtin, in a dry solid powder form, having a purity upto 88%; an emulsion concentrate having upto 30% by weight of azadirachtin, and a process for preparing said azadirachtin dry powder from neem seeds/kernels, which comprising: (a) disintegrating the neem seeds/kernels into a powder; (b) subjecting the said powder to continuous extraction using methanol or aqueous methanol or ethanol (rectified spirit) or aqueous ethanol at ambient temperature; (c) concentrating the extract and stirring the concentrate with petroleumether or hexane and phase separating by conventional methods; (d) stirring the denser phase containing major quantity of azadirachtin with a water immiscible organic solvent and water as required depending on the solvent used for extraction and phase separating by conventional methods; (e) concentrating the organic phase and gradually adding the concentrate to petroleumether or hexane under stirring at ambient temperature (f), filtering under suction and drying under vacuum at a temperature in the range of 25.degree.-65.degree. C. to obtain a neem seed/kernel extract as a powder having azadirachtin of 10-19% purity; (g) redissolving the product obtained in step (f) in a solvent and adding the solution to petroleumether or hexane at ambient temperature gradually under stirring yielding a white solid, which after filtration and drying under vacuum at 65.degree. C. resulting in azadirachtin having 15-26% purity as a white powder (h), dissolving the azadirachtin (10-19%) from step (e) in an organic solvent and subjecting to column chromatography silicagel) by stepwise elution using different compositions of hexane/petroleumether and ethylacetate leading to solid azadirachtin powder upto 49% (i) dissolving the azadirachtin having upto 49% purity in methanol, ethanol or acetonitrile and subjecting it to HPLC (C18 column) to produce azadirachtin of purity upto 88% in a solid powder form, and (j) and stirring the product of step (i) with solvents and emulsifiers with or without synergist and UV stabiliser to obtain the emulsifiable concentrate.

Dependencies are inferred from the claim text.