PESTICIDE NANOPARTICLES OBTAINED FROM MICROEMULSIONS AND NANOEMULSIONS

• US 20100015236A1
• Filed: 09/16/2007
• Published: 01/21/2010
• Est. Priority Date: 09/14/2006
• Status: Active Grant

• Current Assignee: Yissum Research Development Company of the Hebrew University of Jerusalem Ltd. (Hebrew University of Jerusalem)
• Original Assignee: Yissum Research Development Company of the Hebrew University of Jerusalem Ltd. (Hebrew University of Jerusalem)
• Inventors: Dayan, Benny, Levi-Ruso, Ganit, Magdassi, Shlomo
• Granted Patent: US 9,095,133 B2
• Time in Patent Office: Days
• US Class Current: 424/489
• CPC Class Codes: A01N 25/04 Dispersions, emulsions, suspoemulsions, suspension concentrates or gels foams A01N25/16
• CPC Class Codes: A01N 25/14 wettable
• CPC Class Codes: A01N 47/34 containing the groups , e.g. biuret; Thio analogues thereof; Urea-aldehyde condensation products
• CPC Class Codes: A01N 53/00 Biocides, pest repellants or attractants, or plant growth regulators containing cyclopropane carboxylic acids or derivatives thereof

Abstract

The present invention provides a redispersible powder and aqueous dispersions of nanoparticles of water insoluble organic pesticides. The invention further provides methods for preparing the redispersible powder and the aqueous dispersion, wherein the methods include preparation of an oil-in-water nanoemulsion or microemulsion and solvent removal. The present invention also provides pesticidal compositions of the redispersible powder or aqueous dispersions, and their agricultural use in combating pests.

Claims

1-56. -56. (canceled)

57. A process for preparing a redispersible powder comprising nanoparticles of a water-insoluble organic pesticide, the process comprising the steps of:

(i) preparing an oil-in-water emulsion comprising a water-insoluble organic pesticide, a volatile water-immiscible organic solvent, water, and at least one surfactant; and

(ii) removing the volatile water-immiscible organic solvent and the water so as to form a redispersible powder comprising nanoparticles of the pesticide, wherein the nanoparticles are in a particulate form, and wherein the powder has a solubility that is at least about 5 times greater than that of the pesticide in unprocessed form.

58. The process according to claim 57, wherein the step of preparing the oil-in-water emulsion comprises:

(i) dissolving the water-insoluble organic pesticide in the volatile water-immiscible organic solvent so as to form an organic phase; and

(ii) mixing the organic phase with water and a surfactant to form the oil-in-water emulsion.

59. The process according to claim 57, wherein the emulsion is a nanoemulsion formed using a high pressure homogenizer or a high shear instrument, with the nanoemulsion or nanoparticles formed therefrom having a droplet size of less than about 300 nm.

60. The process according to claim 57, wherein the emulsion is a spontaneously formed microemulsion with the microemulsion or the nanoparticles formed therefrom having a droplet size of less than about 30 nm.

61. The process according to claim 57, wherein the volatile water-immiscible organic solvent and water are removed by spray drying or lyophilization.

62. The process according to claim 57, further comprising the step of re-dispersing the powder in water to form an aqueous dispersion of the nanoparticles.

63. The process according to claim 57, wherein the water-insoluble organic pesticide is selected from the group consisting of an insecticide, a herbicide, a fungicide, an acaricide, an algicide, an antimicrobial agent, biopesticide, a biocide, a disinfectant, a fumigant, an insect growth regulator, a plant growth regulator, a miticide, a microbial pesticide, a molluscide, a nematicide, an ovicide, a pheromone, a repellent, a rodenticide, a defoliant, a dessicant and mixtures thereof.

64. The process according to claim 63, wherein the water-insoluble organic pesticide is novaluron or lambda-cyhalothrin.

65. The process according to claim 63, wherein the water-insoluble organic pesticide is an insecticide, herbicide or fungicidally active compound, and further wherein:

the insecticide is selected from the group consisting of a benzoyl urea, novaluron, lufenuron, chlorfluazuron, flufenoxuron, hexaflumuron, noviflumuron, teflubenzuron, triflumuron, diflubenzuron;

a carbamate, a pyrethroid, cyhalothrin and isomers thereof, lambda-cyhalothrin, deltamethrin, tau-fluvalinate, cyfluthrin, beta-cyfluthrin, tefluthrin, bifenthrin;

an organophosphate, azinfos-methyl, chlorpyrifos, diazinon, endosulfan, methidathion;

a neonicotinoid, a phenylpyrazole, imidacloprid, acetamiprid, thiacloprid, dinotefuran, thiamethoxam and fipronil;

the fungicidally active compound is selected from the group consisting of a conazole, epoxiconazole, hexaconazole, propiconazole, prochloraz, imazalil, triadimenol, difenoconazole, myclobutanil, prothioconazole, triticonazole, tebuconazole, a morpholine, dimethomorph, fenpropidine fenpropimorph, a strobilurin, azoxystrobin, kresoxim-methyl, phthalonitriles, chlorothalonil;

mancozeb;

fluazinam;

a pyrimidine and bupirimate; and

the herbicide is selected from the group consisting of an aryloxyphenoxy derivative, an aryl urea, an aryl carboxylic acid, an aryloxy alkanoic acid, clodinafop-propargyl, fenoxaprop-p-ethyl, propaquizafop, quizalafop, a dintroaniline, pendimethalin, trifluralin;

a diphenyl ether, oxyfluorfen, an imidazolinone, a sulfonylurea, chlorsulfuron, nicosulfuron, rimsulfuron, tribenuron-methyl, a sulfonamide, a triazine, a triazinone and metamitron.

66. The process according to claim 57, wherein the volatile water-immiscible organic solvent is selected from the group consisting of n-butyl acetate, sec-butyl acetate, isobutyl acetate, propyl acetate, amyl acetate toluene, xylenes, R(+)-limonene, hexane, pentane, heptane, cyclohexane and mixtures thereof.

67. The process according to claim 57, wherein the emulsion further comprises at least one polymer wherein:

the polymer is a water insoluble polymer selected from the group consisting of polylactic acid, cellulose acetate, methyl cellulose, ethyl cellulose, hydroxylpropyl methyl cellulose, poly(lactic-co-glycolic acid), hydroxylpropyl cellulose phthalate, and mixtures thereof;

or

the polymer is a water soluble polymer selected from the group consisting of polyvinyl pyrrolidone (PVP), polyvinyl alcohol, carboxy methyl cellulose, hydroxy ethyl cellulose, polyethylene glycol, and mixtures thereof;

or

the polymer is a non-crosslinked polymer; and

the polymer is present in an amount of about 0.01 to about 10% by weight based on the total weight of the emulsion.

68. The process according to claim 57, wherein the emulsion further comprises a re-dispersion aid which is selected from the group consisting of a wetting agent, a disintegrant, a water soluble polymer, colloidal silica particles, sugars, mannitol and mixtures thereof;

or

wherein the emulsion further comprises a co-solvent.

69. The process according to claim 57, wherein the at least one surfactant is selected from the group consisting of a cationic surfactant, an anionic surfactant, an amphoteric surfactant, a nonionic surfactant and mixtures thereof, and further wherein:

the anionic surfactant is selected from the group consisting of an alkyl benzene sulphonate, condensate sodium salts, sodium dodecyl sulfate, sodium sulfosuccinate, sodium lauryl sulfate, sodium stearate, sodium alkyl naphthalene sulfonate and mixtures thereof;

the nonionic surfactant is selected from the group consisting of an ethoxylated sorbitan ester, a sorbitan ester, an organosilicone surfactant, a polyglycerol ester, a sucrose ester, a poloxamer, an alkyl polyglucoside, polyalkyleneoxide modified heptamethyltrisiloxanes, and allyloxypolyethylene glycol methylether and mixtures thereof;

or

the amphoteric surfactant is lecithin;

or

the cationic surfactant is selected from the group consisting of cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, and mixtures thereof;

or

wherein the surfactant is sodium n-butyl naphthalene sulfonate or an organosilicone surfactant comprising a blend of polyalkyleneoxide modified heptamethyltrisiloxane and allyloxypolyethylene glycol methyl ether.

70. The process according to claim 57, wherein the water-insoluble organic pesticide is in an amorphous or a partially amorphous form.

71. The process according to claim 57, further comprising the step of crystallizing the nanoparticles, thereby providing crystalline organic nanoparticles.

72. A redispersible powder comprising nanoparticles of a water-insoluble organic pesticide, obtainable by the process according to claim 57, wherein the nanoparticles have a diameter of about 5 to about 300 nm.

73. An aqueous dispersion comprising nanoparticles of a water-insoluble organic pesticide, obtainable by the process according to claim 62.

74. A pesticidal composition comprising the redispersible powder according to claim 57 and an acceptable adjuvant.

77. A redispersible powder comprising at least 5% by weight of nanoparticles of a water-insoluble organic pesticide, wherein the nanoparticles are in a particulate form and are produced in accordance with the process of claim 57, wherein the nanoparticles have a dissolution rate in water that is at least about 5 times greater than the dissolution rate of the water-insoluble pesticide in unprocessed form.

78. The redispersible powder according to claim 77, wherein the nanoparticles have a diameter of less than about 300 nanometers.

79. The redispersible powder according to claim 77, wherein the nanoparticles comprise at least about 80% by weight of the water-insoluble organic pesticide, selected from the group consisting of an insecticide, a herbicide, a fungicide, an acaricide, an algicide, an antimicrobial agent, biopesticide, a biocide, a disinfectant, a fumigant, an insect growth regulator, a plant growth regulator, a miticide, a microbial pesticide, a molluscide, a nematicide, an ovicide, a pheromone, a repellent, a rodenticide, a defoliant, a dessicant and mixtures thereof.

80. The redispersible powder according to claim 77, wherein the water-insoluble organic pesticide is in an amorphous form or a partially amorphous form.

81. The redispersible powder according to claim 77, further comprising at least one polymer.

82. An aqueous dispersion comprising the redispersible powder of claim 77 and an aqueous medium.

83. An emulsion obtainable by the process according to claim 57.

75. A process for preparing an aqueous dispersion comprising nanoparticles of a water-insoluble organic pesticide, the process comprising the steps of:

(i) preparing an oil-in-water emulsion comprising a water-insoluble organic pesticide, a polymer, a volatile water-immiscible organic solvent, water, and at least one surfactant; and

(ii) removing the volatile water-immiscible organic solvent so as to form an aqueous dispersion comprising said nanoparticles, wherein the nanoparticles are in a particulate form and have a solubility that is at least about 5 times greater than that of the pesticide in unprocessed form.

76. An aqueous dispersion comprising nanoparticles of a water-insoluble organic pesticide, obtainable by the process according to claim 75.