COMBINATION IRS WITH INDOXACARB AND PERMETHRIN

Background of the Invention

Permethrin, a synthetic pyrethroid is well known in IRS applications for the control of mosquitoes. Owing to the spread of pyrethroid resistance in Anopheles gambiae & other vector mosquitoes, there is an urgent need to develop alternative insecticides to supplement the pyrethroids for malaria vector control.
WO2008030385 describes the formulation for control of ectoparasites on a domestic animal comprising an indoxacarb and veterinarily acceptable carrier.

WO2000054586 describes the formulation containing pyrethroid insecticides, particularly the pyrethroids which are esters of phenoxybenzyl alcohol with substituted dimethyl cyclopropane carboxylic acid, such as permethrin, cypermethrin, deltamethrin, cyhalothrin etc.

Indoxacarb is an oxadiazine insecticide which provides an alternative for pyrethroid resistant, Anopheles gambiae & other similar type of mosquitoes.

Hence there exists a need for a novel formulation with the combination of these two insecticides, Indoxacarb and permethrin to provide a better solution for the control of different types of mosquitoes.

Summary of the invention

It is an object of invention to provide combination formulation of Indoxacarb and Permethrin in the form of Wettable Powders (WP).

It is another object of invention to provide combination formulation of Indoxacarb and Permethrin in the form of Suspension Concentrates (SC).

It is yet another object of invention to provide combination formulation of Indoxacarb and Permethrin in the form of Water Dispersible Granules (WG/WDG).

Detailed description of the invention

Wettable Powder (WP) formulation of a mixture of Indoxacarb and Permethrin
The typical ingredients of combination wettable powder formulation of Indoxacarb and Permethrin include the active ingredients, inert substances as carriers, dispersing agents, wetting agents, defoamers, etc. The inert substances help to disperse the active ingredients, improve effectiveness, reduce toxicity, or break the active ingredients down into smaller parts, making the resulting formulation diluted, and easier to apply.

Typically, the active ingredients Permethrin comprises 2 to 40% and preferably from 5 to 25%; and Indoxacarb comprises 1 to 30% and preferably from 2 to 20% of the dry weight of the formulation.

In addition to the active ingredient component, the ingredients will normally include dispersants, wetting agents, defoamers, and inert fillers.

The dispersing agent generally comprises 1 to 25% and preferably from 3 to 15% by weight of the dry weight of the composition. Dispersing agents described in this process include naphthalene condensates, lignosulfonates, poly acrylates and phosphate esters.

The wetting agent generally comprises 0.1 to 20% and preferably from 1 to 10% by weight of the dry weight of the composition. Wetting agents described in this process include alkyl naphthalene sulfonates, lauryl sulfates, sulfosuccinates, phosphate esters and ethoxylates.

The filler component generally comprises 0 to 95% and preferably 1 to 80% by weight of the dry weight of the composition. Fillers described in this process include lactose, sucrose, saccharides, precipitated silica, fumed silica, cellulose, china clay, talc, starch, maize, diatomaceous earth, atapulgite, kielserghur, calcium carbonate, magnesium carbonate, silica etc.

The defoamer component generally comprises 0 to 10% and preferably 0.1 to 4% by weight of the dry weight of the composition. Defoamers described in this process include silica activated poly siloxane emulsion, blend of fatty esters emulsified in water, mineral oil based defoamer etc.

Typical example: Permethrin (20%), Indoxacarb (5%), wetting agent naphthalene sulfonates (3%), dispersing agent naphthalene - formaldehyde condensate (8%), precipitated silica (2%), antifoaming agent silicone compound (1%) & china clay (q.s to 100%) were pre-blended and milled in air jet mill to achieve a particle size in the range of 10 microns.

Bio-efficacy Results:

Suspension Concentrates (SC) formulation of a mixture of Indoxacarb and Permethrin
The typical ingredients of combination suspension concentrate formulation of Indoxacarb and Permethrin include the active ingredients, inert substances as carriers, dispersing agents, wetting agents, thickening agents, anti-freezing agents, defoamers, solubilisers & water. The inert substances help to disperse the active ingredients, improve effectiveness, reduce toxicity, or break the active ingredients down into smaller parts, making the resulting formulation diluted, and easier to apply.

Typically, the active ingredients Permethrin comprises 2 to 40% and preferably from 5 to 25%; and Indoxacarb comprises 1 to 30% and preferably from 2 to 20% of the total weight of the formulation.

In addition to the active ingredient component, the ingredients will normally include dispersants, wetting agents, defoamers, thickeners, solubilisers and water.

The dispersing agent generally comprises 1 to 25% and preferably from 3 to 15% by weight of the total weight of the composition. Dispersing agents described in this process include naphthalene-formaldehyde condensates, lignosulfonates, poly acrylates, graft polymers and phosphate esters.

The wetting agent generally comprises 0.1 to 20% and preferably from 1 to 10% by weight of the total weight of the composition. Wetting agents described in this process include alkyl naphthalene sulfonates, lauryl sulfates, sulfosuccinates, phosphate esters and ethoxylates.

The anti-freezing agents generally comprises 1 to 25% and preferably from 2 to 15% by weight of the total weight of the composition. Anti-freezing agents described in this process include ethylene glycol, propylene glycol, hexylene glycol, glycerol etc.

Examples of suitable preservatives are aqueous dipropylene glycol solution of 1,2-benzisothiazolin-3-one (commercially available as Proxel GXL), potassium sorbate, formaldehyde solution etc. They are added in amount of preferably 0.01 to 5%, particularly 0.1 to 1% by weight.

Preferred antifoams and defoamers are based on silicone, particularly preferred are an aqueous emulsion of dialkylpolysiloxanes or blend of fatty esters emulsified in water, mineral oil based defoamers. Antifoams are added in an amount of generally 0.01 to 3% by weight, preferably 0.05 to 1% by weight.

The thickening agents generally comprises 1 to 15% and preferably from 0.5 to 5% by weight of the total weight of the composition. Thickening agents described in this process include precipitated silica, fumed silica, xanthum gum, guar gum, poly vinyl alcohols, poly vinyl esters, poly acrylic acids etc.

Solubilisers generally comprises 5 to 40% and preferably from 10 to 25% by weight of total weight of the composition. Solubilisers described in this process include vegetable oils such as capric/caprylic triglycerides, corn oil, rape seed oil, sun flower oil, isopropyl myristate, ethylene glycol mono methyl ether, etc.

The formulation generally comprises 10 to 75% by weight, preferably 25 to 50% by weight, of water.

Typical example: Permethrin (20%), wetting agent naphthalene sulfonates (2%), dispersing agent naphthalene - formaldehyde condensate (4%), precipitated silica (1%), anti-freezing agent, propylene glycol (8%), antifoaming agent silicone compound (0.25%), preservative formaldehyde solution (0.75%), thickener poly acrylic acid (0.1%) & water (35%) were premixed in laboratory mixer. Indoxacarb (5%) was dissolved in solubiliser, vegetable oil (17%) and mixed with the above suspension. The pre-milled aqueous suspension was milled in a horizontal bead mill to a particle size of 1 - 3 microns & 2% xanthum gum solution (5%) was mixed with the milled suspension in high shear homogenizer.

Water dispersible granule (WDG) formulation of a mixture of Indoxacarb and Permethrin
The typical ingredients of combination water dispersible granules of Indoxacarb and Permethrin include the active ingredients, inert substances as carriers, dispersing agents, wetting agents, disintegrating agents, etc. The inert substances help to disperse the active ingredient, improve effectiveness, reduce toxicity, or break the active ingredient down into smaller parts, making the resulting formulation diluted, and easier to apply.

The present invention describes the process for water dispersible granules by mixing the desired ingredients together to an extrudable form by mixing the ingredients with water and extruded to get wet extrusion granules. The wet granules are dried in a fluidized bed drier or hot air dryer to form uniform extrusion granules. The granules thus obtained have high dispersion and suspensibility when compared to granules obtained in pan granulator.

Typically, the active ingredients Permethrin comprises 2 to 40% and preferably from 5 to 25%; and Indoxacarb comprises 1 to 30% and preferably from 2 to 20% of the total weight of the formulation.

In addition to the active ingredient component, the ingredients will normally include dispersants, wetting agents, defoamers, and inert fillers.

The dispersing agent generally comprises 1 to 25% and preferably from 4 to 15% by weight of the dry weight of the composition. Dispersing agents described in this process include naphthalene condensates, lignosulfonates, poly acrylates and phosphate esters.

The wetting agent generally comprises 0.1 to 20% and preferably from 1 to 10% by weight of the dry weight of the composition. Wetting agents described in this process include alkyl naphthalene sulfonates, lauryl sulfates, sulfosuccinates, phosphate esters and ethoxylates.

The filler component generally comprises 0 to 95% and preferably 1 to 80% by weight of the dry weight of the composition. Fillers described in this process include lactose, sucrose, saccharides, cellulose, china clay, talc, starch, maize, diatomaceous earth, atapulgite, kielserghur, calcium carbonate, magnesium carbonate, silica etc.

The defoamer component generally comprises 0 to 10% and preferably 0.1 to 4% by weight of the dry weight of the composition. Defoamers described in this process include silica activated poly siloxane emulsion, blend of fatty esters emulsified in water, mineral oil based defoamer etc.

The disintegrating agent component generally comprises 0 to 10% and preferably 0 to 2% by weight of the dry weight of the composition. Disintegrants described in this process include starch, sodium glyconate, silica etc.

The water is preferably present in the wet mixing step of the process in a controlled amount to dough-like consistency so that there is sufficient water to mobilize the surfactant component and enable the mixture to be formed into granules by extrusion method but insufficient to cause the granules to stick together and agglomerate once formed. Even though the quantity of water may vary from the given formulation, it will be generally in the range of 1 to 50% preferable 3 to 20% of the dry weight of the composition.

The order of addition of ingredients is not critical. The pre-milled solid mix of active ingredient, dispersants, wetting agents, disintegrants and filler was milled in air jet mill and the milled dry components were wetted with water, defoamer and extruded to appropriate consistency. The wet granules are dried form uniform extrusion granules.

The drying process will preferably eliminate maximum amount of water in order to provide good stability to the granular product in a dry flowable state.

Typical example of the combination water dispersible granules of Permethrin and Indoxacarb:

Typical example: The active ingredients, Permethrin (20%), Indoxacarb (5%), wetting agent, polyalkoxy alkyl ether phosphate ester (5%), dispersing agent, anionic styrene acrylate (8%), defoamer, silica activated polysiloxane emulsion (3%) & inert filler (59%) were pre-mixed and milled in air jet mill. The milled powder was wetted with water (10%) and extruded in extruder to form wet extrusion granules. The wet granules were dried in a hot air dryer at 50 - 60°C for 2 hours to obtain free flowing uniform granules.

Claim

1. An insecticidal composition of Indoxacarb and permethrin in the form of a suspension concentrate, wettable powder, water dispersible granule.

2. A composition of Indoxacarb and permethrin for application as Indoor Residual Spray.