Pesticidal formulation

Details Pesticidal formulation Pesticidal formulation

1999-05-25

2002-05-14

Levy, Neil S. (Department: 1616)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Biocides; animal or insect repellents or attractants

C424S405000, C424S406000, C424S417000, C514S030000

Reexamination Certificate

active

06387388

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to pesticidal compositions comprising a water-soluble pesticide and process for their manufacture. More specifically, the invention relates to soluble granule (SG) formulations comprising a water-soluble pesticide and a water-soluble filler.
BACKGROUND OF THE INVENTION
Emulsifiable concentrate (EC) agricultural formulations of pesticides are well known in the art. These formulations generally comprise emulsifying and dispersing agents in addition to the pesticide to give a uniform solution. However, these agricultural formulations suffer numerous drawbacks because they are liquid. In particular, liquid pesticidal formulations must be handled carefully to minimize safety concerns, particularly dermal and ocular irritation.
Although solvent-free pesticidal compositions are known, most solvent-free pesticidal formulations have lower bioactivity than the corresponding emulsifiable concentrate formulations. Thus, one skilled in the art frequently has been forced to choose between using a solvent to give a more bioactive formulation but with higher dermal and ocular toxicity, or having a less active solid formulation.
The present invention overcomes the drawbacks of liquid formulations by taking advantage where possible of the water solubility of the pesticide to furnish a composition in divided form so that it will dissolve in water.
Certain methods for preparing water-soluble granules of pesticides are known in the art. PCT Publication No. WO 90/12503 discloses the formation of alkaline salts of soluble acidic or phenolic pesticides to give a granular composition. U.S. Pat. No. 4,511,395 discloses wettable herbicidal powder compositions which comprise a swelling hydrous silicate clay. EPO Publication No. EP 0,111,112 discloses pesticide granules comprising an inert carrier and a pesticide, and which are coated with finely divided silica.
The use of lactose as a solid filler to make tablets is well known in the pharmaceutical industry. (See e.g. Lerk, C. F., “Consolidation and Compaction of Lactose”
Drug Development and Industrial Pharmacy,
19, 2359 (1993); “Role of Ingredients and Excipients in Developing Pharmaceuticals”
Manufacturing Chemist,
p. 32 (April 1994). Nevertheless, the use of lactose or other water-soluble fillers as agricultural inert ingredients is not common in formulating pesticides for crop protection. Hudson and Tarwater (Reduction of Pesticide Toxicity by Choices of Formulation, J. L. Hudson and O. R. Tarwater, in
ACS Symposium series #
371,
Pesticide Formulations,
B. Cross and H. B. Scher, eds.) discuss the effect the choice of formulation on toxicity, and state (on p. 129) that the ocular irritation can be very different for different formulations of the same active ingredient, and that changes in the other toxicity categories may occur. Nevertheless, they do not discuss how such diminished toxicity may be achieved. Furthermore, they mention wettable powders (WP), water dispersible granules (WDG) or dry flowables (DF), but they do not even mention soluble granule (SG) formulations.
The soluble granule (SG) formulation of the present invention has numerous advantages over the corresponding liquid formulation of a given pesticide. Because it is a solid, the SG formulation exhibits improved ease of handling relative to the liquid formulation. Nevertheless, when dissolved in water the SG formulation provides a clear solution which is aesthetically pleasing. The SG formulation also minimizes the use of ingredients of environmental concern by eliminating the need for volatile organic compounds and employing fillers which are biologically derived, thereby diminishing the potential environmental impact. In addition, formulations of higher concentration (hence lower cost per kg of active ingredient formulated) can be achieved without any loss in biological activity with respect to a liquid formulation. Because the dried granules in the SG formulation are of roughly constant bulk density, the granules may be measured by volume, thus making them equally convenient to liquid formulations in ease of use.
More importantly, however, use of the instant SG formulation is less risky to personnel than the corresponding liquid formulation. Risk of exposure is generally evaluated under the guide: risk=hazard×exposure. Because the instant SG formulation is less toxic, the hazard is decreased. In addition, the probability of contact is lower when the material is in a solid rather than a liquid form and hence the degree of exposure is also reduced. The present invention also affords relatively hard non-dusty granules, thereby even further diminishing the risk of exposure to dust from the composition. Also, the present invention may be practiced without the use of mineral fillers which contain crystalline silica, a known carcinogen. Thus, the present invention diminishes the risk of exposure and provides greater handler safety, especially with regard to ocular irritation, than a liquid formulation.
Accordingly, the present invention provides a relatively safe, bionatural delivery system for a pesticide which is water soluble at the concentration at which it is employed.
SUMMARY OF THE INVENTION
The present invention relates to a pesticidal composition of a water-soluble pesticide and processes for its manufacture. More specifically, the invention relates to a soluble granule (SG) pesticidal formulation comprising a water-soluble pesticide and a water-soluble filler. The present invention provides a pesticidal formulation with efficacy equal to the corresponding liquid formulation, yet with improved handler safety, such as lower eye irritation.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed to an pesticidal composition comprising a water-soluble pesticide and processes for its manufacture. More specifically, the invention relates to a soluble granule (SG) formulation comprising a water-soluble pesticide, such as emamectin benzoate, and a water-soluble filler, such as lactose.
The pesticidal composition of the present invention comprises: a water-soluble pesticide; and a water-soluble filler.
The present pesticidal composition may further comprise: a wetting surfactant; and/or a dispersing surfactant. Optionally, a defoaming agent may also be present.
Preferably the water-soluble pesticide is selected from: emamectin or an agriculturally acceptable salt thereof. Preferably the water-soluble filler is selected from: lactose, sucrose, glucose, and the like. Preferably the wetting surfactant is selected from: sodium N-methyl-N-oleyl taurate, sodium N-methyl-N-palmityl taurate, sodium N-methyl-N-oleoyl taurate, sodium dioctyl sulfosuccinate and other sodium alkyl sulfosuccinates, sodium lauryl sulfate, alpha-(p-nonylphenyl)-omega-hydroxy poly(oxyethylene) with an average of 8-12 moles of ethylene oxide, and alpha-(p-octylphenyl)-omega-hydroxy poly(oxyethylene) with an average of 7-12 moles of ethylene oxide. Preferably the dispersing surfactant is selected from: sodium alkyl naphthalene sulfonate, sodium napthalene sulfonate, calcium lignosulfonate, sodium lignosulfonate, and ammonium lignosulfonate. Preferably the defoaming agent is selected from: methylated silicones, polyorganosiloxane, and 2-ethylhexanol.
More preferably the water-soluble pesticide is emamectin or emamectin benzoate. More preferably the water-soluble filler is lactose. More preferably the wetting surfactant is sodium N-methyl N-oleyl taurate. More preferably the dispersing surfactant is sodium alkyl naphthalene sulfonate. More preferably the defoaming agent is polyorganosiloxane.
The pesticidal composition of the present invention may be provided in the form of a wettable powder but preferably is in the form of a water-soluble granule. Similarly, the pesticidal composition of the present invention may be provided as an aggregate, a matrix, or a monolith, such as a brick, pellet, tablet, stick, film, sheet, and the like. Preferably, the pesticidal composition of the present invention is embedded in a water-soluble matr

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