PESTICIDAL DRY POWDER FORMULATION ENRICHED IN AZADIRACHTIN UPTO 88, AN EMULSIFIABLE CONCENTRATE ENRICHED UPTO 30 OF AZADIRACHTIN AND A PROCESS FOR PREPARING SUCH FORMULATION ANDCONCENTRATE FROM NEEM SEED/KERNEL

摘要

The invention relates to a preparation of azadirachtin, in a dry solid powderform,having a purity upto 88% ; an emulsion concentrate having upto 30% by weightofazadirachtin, and a process for preparing said azadirachtin dry powder fromneemseeds/kernels, which comprising: (a) disintegrating the neem seeds/kernelsinto apowder; (b) subjecting the said powder to continuous extraction using methanoloraqueous methanol or ethanol (rectified spirit) or aqueous ethanol at ambienttemperature; (c) concentrating the extract and stirring the concentrate withpetroleumether or hexane and phase separating by conventional methods; (d)stirring the denser phase containing major quantity of azadirachtin with awaterimmiscible organic solvent and water as required depending on the solvent usedfor extraction and phase separating by conventional methods; (e) concentratingtheorganic phase and gradually adding the concentrate to petroleumether or hexaneunder stirring at ambient temperature (f), filtering under suction and dryingundervacuum at a temperature in the range of 25 - 65°C. to obtain a neemseed/kernelextract as a powder having azadirachtin of 10-19% purity; (g) re~dissolvingtheproduct obtained in step (f) in a solvent and adding the solution topetroleumetheror hexane at ambient temperature gradually under stirring yielding a whitesolid,which after filtration and drying under vacuum at 65°C. resulting inazadirachtinhaving 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 ofhexane/petroleumether and ethylacetate leading to solid azadirachtin powderupto49% (i) dissolving the azadirachtin having upto 49% purity in methanol,ethanol oracetonitrile and subjecting it to HPLC (C18 column) to produce azadirachtin ofpurity upto 88% in a solid powder form, and (j) and stirring the product ofstep(i) with solvents and emulsifiers with or without synergist and UV stabilisertoobtain the emulsifiable concentrate.