WO2015102023A1

WO2015102023A1 - A novel water dispersible granular composition and process for preparing the same

Info

Publication number: WO2015102023A1
Application number: PCT/IN2015/000001
Authority: WO
Inventors: Mundhra Parikshit; Mohan Jitendra
Original assignee: Willowood Chemicals Private Limited
Priority date: 2014-01-03
Filing date: 2015-01-01
Publication date: 2015-07-09

Abstract

The present invention relates to a novel water dispersible granular composition comprising triazophos as the active ingredient in an effective amount. Said novel water dispersible granular composition is used for wide spectrum control of insect pests delaying the preeminence of the resistant strains, minimizing the risk of development of resistance and achieving and economical control of undesired pets. The invention further relates to a process of preparing the water dispersible granular composition.

Description

A NOVEL WATER DISPERSIBLE GRANULAR COMPOSITION AND PROCESS FOR

PREPARING THE SAME

FIELD OF THE INVENTION

The present invention relates to an insecticidal composition, more particularly to a novel water dispersible granular composition comprising Triazophos for agricultural use and a process for preparing such novel water dispersible granular composition.

BACKGROUND OF INVENTION

A large number of biologically active substances have been extensively used in various formulations for agricultural purposes for the control of weeds, insects, fungi and other pests and are usually referred to as pesticides.

These active substances can be solids, liquids or low melting solids. When the active substances are in a liquid state at ambient temperatures they have been formulated in a number of ways. To the varying extents these formulations are adapted for ease of transport, handling and field applications.

In the context of the steadily increasing demands of modem crop protection, new, optimized variations on existing formulation types and of course new concepts is required. It is generally desirable to deliver the formulations with liquid active substances in the form of an aqueous spray, the examples of which are emulsifiable concentrate (EC), wettable powder (WP), suspension concentrate (SC) and water dispersible granules (WG). However, the compositions formulated as EC, WP and SC offers various disadvantages. Limitations of EC formulation include the dangers in packaging, storing and handling highly flammable solvents. For insoluble active substances, wettable powders (WP) used to be the preferred formulation type. However, these type of formulations tend to form dust and are difficult to dose out. WP formulations therefore, can present handling problems and potential health hazard to the user. The SC formulations can have storage problems and are difficult to clean up after spillage. Nowadays, the problems offered by EC, WP and SC formulations are solved by choosing water dispersible granules as the preferred formulations. These are dust-free in practice and allow the inclusion of large amounts of active substance in the product. So, WG formulations are particularly useful for active substances that need to be applied at high rates. In this way, even if the production costs are relatively high, the cost per hectare can usually be kept down. WG formulations generally show good crop compatibility, so they are often used for more sensitive crops, such as grapevine.

WG formulations comprising solid active substances having relatively high melting point (m.p > 70 C) are well known. They can be prepared by several techniques such as extrusion, spray granulation and pan granulation. However, difficulties have been observed in developing free flowing, dustless dispersible WG formulations comprising liquid or low- melting active substance (m.p < 70 C) due to the physical nature of these actives.

Therefore, there is a need for developing stable WG formulations loaded with higher concentration of liquid active substances. Triazophos, a liquid organophosphorus insecticide, acaricide and nematicide (IUPAC Name: Ο,Ο-diethyl O-l -phenyl- lH-l,2,4-triazol-3-yl phosphorothioate, Molecular formula: C₁₂Hi6N₃0₃PS, Molecular weight: 313.3) was reported as an insecticide by M. Vulic et. al. in Abstr. Int. Congr. Plant Prot. 7th, Paris, 1970, p. 123. It was introduced in the year 1973. Triazophos is an insecticide, acaricide and nematicide that shows a broad-spectrum activity against a wide range of sucking pests, mites and some Lepidoptera. It is a non-systematic cholinesterase inhibitor and has contact and stomach action leading to deep penetration into the plant tissues. Triazophos also exhibits ovicidal action against eggs of mites and Heliothis and possesses nematicidal properties against certain free-living nematodes. Products containing triazophos as the active substance are commercially available as single active EC formulations or as combinations with other actives, for instance combination of triazophos and deltamethrin (EC). Many triazophos formulations are known in the prior art. Granted Chinese Patent CN 101002569 B discloses triazophos formulation in the form of a water emulsion, wherein the aqueous emulsion comprises 5-40% triazophos. Granted Chinese Patent CN 101258848 B provides a solid micro-emulsion containing triazophos and method of preparation of the same. The triazophos content varies from 5- 45%. However, solid micro emulsions are uncommon, because few active substances are liquids or possess the suitable solubility properties. Granted United States Patent US5739081 discloses water dispersible granules suitable for agricultural application prepared by first preparing absorbent water dispersible granules and then loading biologically active substances (triazophos) into the preformed absorbent granules.

In the view of the disadvantages offered by EC and solid micro emulsion, there is a need to provide the user with immensely beneficial triazophos WG granules which are distinguished by several user and environment friendly characteristics such as ease of use, storage, freedom from dust and minimum use of toxic, volatile, inflammable, nonbiodegradable solvents etc.

The triazophos products available in the market are mostly in EC form and go as high as 40% of triazophos. Several difficulties arise in developing free flowing, dustless dispersible WG triazophos formulations with high concentration of triazophos wherein triazophos is going beyond 10%.

Thus, there is a need for alternative granulation method in order to enable WG formulation of triazophos in higher concentration in an economic and effective manner. It is therefore an object of the present invention to provide a novel water dispersible granular formulation comprising higher concentration of triazophos and the process of preparation of the same. The other object of the present invention is to provide a useful alternative in the granulation art which in certain situations will provide a number of advantages over currently employed techniques. SUMMARY OF INVENTION

The present invention relates to a novel water dispersible granular composition and the process for preparation thereof.

According to an embodiment of the invention there is provided a novel water dispersible granular composition (WG) comprising: - at least one liquid agrochemically active substance;

- at least one wetting agent; and

- at least one agrochemically acceptable excipient.

According to another embodiment of the invention there is provided a water dispersible granular composition (WG), wherein the liquid agrochemically active substance is an insecticide.

According to another embodiment of the invention, the liquid agrochemically active substance is an insecticide and preferably triazophos.

According to another embodiment of the invention, triazophos is present in an amount of 15-20% w/w.

According to another embodiment of the invention, triazophos is preferably present in an amount of 20% w/w.

According to another embodiment of the invention, the wetting agent is selected from the group consisting of acrylate polymer alone or in combination thereof. According to another embodiment of the invention, the wetting agent is preferably sodium salt of styrenated methyl acrylate.

According to another embodiment of the invention, the wetting agent is present in an amount of 2-5% w/w.

According to another embodiment of the invention, the excipients are selected from the group comprising of surfactants, absorbents, carriers, dispersing agents, fillers etc. alone or in combination thereof.

According to another embodiment of the invention, the surfactant is selected from the group consisting of blend of aldehyde condensate, naphthalene sulphonic acid and sulphosuccinate alone or in combination thereof. According to another embodiment of the invention, the surfactant is preferably a blend of modified naphthalene sulphonate formaldehyde condensate, butylated naphthalene sulphonic acid and dioctyl sulphosuccinate. According to another embodiment of the invention, the surfactant is present in an amount of 8- 12% w/w.

According to another embodiment of the invention, the absorbent is selected from the group consisting of silicates alone or in a combination thereof. According to another embodiment of the invention, the absorbent is preferably ammonium precipitated silica.

According to another embodiment of the invention, the absorbent is present in an amount of 10-20% w/w.

According to another embodiment of the invention, the carrier is selected from the group consisting of sulphates alone or in combination thereof.

According to another embodiment of the invention, the carrier is preferably ammonium sulphate.

According to another embodiment of the invention, the carrier is present in an amount of 25-35% w/w. According to another embodiment of the invention, the dispersing agent is selected from the group consisting of lignosulphonates alone or in combination thereof.

According to another embodiment of the invention, the dispersing agent is preferably sodium lignosulphonate.

According to another embodiment of the invention, the dispersing agent is present in an amount of 3-5% w/w.

According to another embodiment of the invention, the filler is selected from the group consisting of china clay alone or in combination thereof.

According to another embodiment of the invention, the filler is preferably sodium china clay. According to another embodiment of the invention, the filler is present in quantity sufficient. According to an embodiment of the invention there is provided a process for preparing a novel water dispersible granular (WG) composition, said process comprising the steps:

- Charging all ingredients except Triazophos technical in a pre-blender and mixing for 30 minutes to get a mixture A.

- Milling mixture A with air classifier mill (ACM) that results in powder B.

- Collecting powder B in a post-blender and mixing for 30 minutes thereafter to obtain powder C.

- Transferring the above powder C in a dough mixer.

- Spraying Triazophos technical to the powder C to get dough D.

- Transferring dough D to extruder by maintaining temperature of extruder below 70^°C.

- Starting granulation of the dough D with extruder to obtain granules E.

- Drying granules E at 70 C

According to another embodiment of the invention there is provided a water dispersible granular (WG) composition comprising at least one liquid agrochemically active substance; at least one wetting agent acting as wetting agent; and at least one agrochemically acceptable excipient, said water dispersible granular (WG) composition prepared by the process as discussed above, wherein the liquid agrochemically active substance being triazophos. The novel water dispersible granular composition of the present invention exhibits high dispersibility, suspensibility, increased bio-efficacy, low environmental load, low inhalation toxicity to the applicators, no phyto-toxicity among other advantages which include packing, transportation, storage etc. Most importantly the novel water dispersible granular composition is free from basic problems of sedimentation/stability faced with currently available liquid commercial formulations of triazophos due to inherent characteristics of the active ingredients. DESCRIPTION OF INVENTION

Discussed below are some representative embodiments of the present invention. The invention in its broader aspects is not limited to the specific details pertaining to the embodiments and representative methods. The illustrative examples are described in this section in connection with the embodiments and methods provided. The invention according to its various aspects is particularly pointed out and distinctly claimed in the appended claims read in view of this specification and appropriate equivalents.

It is to be noted that, as used in the specification and the appended claims, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a composition containing "a compound" includes a mixture of two or more compounds. It should also be noted that the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.

The expression of various quantities in terms of "% w/w" means the percentage by weight, relative to the weight of the total solution or composition unless otherwise specified.

As used herein, the expressions "EC formulation", "SC formulation", "WP formulation" and "WG formulation" are the international denominations adopted by the FAO (Food and Agricultural Organization of the United Nations) to designate "emulsifiable concentrate", "aqueous suspension of solid fine particles", "wettable powder" and "water dispersible granules" respectively.

The term "water dispersible granular formulation" (WG) is a pesticide formulation in the form of granules that are applied after disintegration and dispersion in water. The "granules" are nothing but distinct particles within the range 0.2 to 4 mm. The WG formulations are also alternatively referred to as Water dispersible granules (WDG).

Accordingly, there is provided a novel water dispersible granular composition (WG) comprising at least one liquid agrochemically active substance; at least one wetting agent acting as wetting agent; and at least one first agrochemically acceptable excipient. In this specification, the term "agrochemically active substance" is used in its broadest sense to include all classes of insecticides. The biologically active substance in accordance with the present invention needs to be in a liquid form or formed into a liquid state, by for example dissolution in a suitable solvent. In an embodiment of the invention, the liquid agrochemically active substance is an insecticide and preferably triazophos.

Triazophos is a liquid organophosphor^ous insecticide, acaricide and nematicide. It is a broad spectrum insecticide with contact and stomach action against a wide range of sucking pests, mites and some lepidoptera in ornamentals, fruits and vegetables, cotton, paddy, oil seeds, sugarcane etc. Triazophos is non-systemic but penetrates deeply into plant tissues. Triazophos also exhibits ovicidal action against eggs of mites and heliothis and possesses nematicidal properties against certain free-living nematodes. It inhibits the acetylcholine esterase and is known to have a translaminar action. According to an embodiment of the invention, triazophos is present in an amount of 15-20% w/w and more preferably in an amount of 20% w/w.

According to another embodiment of the invention, the wetting agents are selected from the group consisting of acrylate polymer alone or in combination thereof and are present in an amount of 2-5% w/w. In a preferred embodiment said wetting agent is sodium salt of styrenated methyl acrylate (Jeesperse d777). The excipients contemplated by the novel water dispersible granular composition of the present invention include surfactants, absorbents, carriers, dispersing agents, fillers etc. alone or in combination thereof.

According to a further embodiment, the surfactants used to formulate the water dispersible granular composition of present invention are selected from the group consisting of blend of aldehyde condensate, naphthalene sulphonic acid and sulphosuccinate alone or in combination thereof and are present in an amount of 8-12% w/w. In a preferred embodiment of the invention, the surfactant is a blend of modified naphthalene sulphonate formaldehyde condensate, butylated naphthalene sulphonic acid and dioctyl sulphosuccinate (Jeemol DW). However, those skilled in the art will appreciate that it is possible to utilize other surfactants known in the art without departing from the scope of the invention. Suitable absorbents can be used to formulate the water dispersible granular composition of the present invention. The absorbent may be selected from the group consisting of silicates alone or in combination thereof. The absorbent is present in an amount of 10-20% w/w in the water dispersible granular composition of the present invention. However, those skilled in the art will appreciate that it is possible to utilize other absorbents known in the art without departing from the scope of the invention.

Various carriers may be used in combination with the liquid agrochemically active substance, the wetting agent and the suitable excipients. Carriers, premixed with the formulation before packaging or added to a spray tank prior to spraying, are designed to increase efficacy of said formulation or to improve the application characteristics of the formulations. Since the carriers acts in some manner to improve the effectiveness of the active ingredient, the amount of active ingredient needed to be effective can be reduced in many cases, without a loss in efficacy. The suitable carrier for use in the novel water dispersible composition of present invention is selected from group consisting of sulphates alone or in combination thereof and present in an amount of 25-35% w/w. In a preferred embodiment, the carrier is preferably ammonium sulphate and present in an amount of 30% w/w. However, those skilled in the art will appreciate that it is possible to utilize other carriers known in the art without departing from the scope of the invention. The term "dispersing agent" refers to a compound which ensures that the particles remain suspended in the application mixture and which allows rapid disintegration of the granule in the water. The dispersing agent can be an ionic or non-ionic agent or a mixture of such surface active agents. According to an embodiment of the present invention, the dispersing agents are selected from the group consisting of lignosulphonates alone or in combination thereof and are present in an amount of 3-5% w/w. However, those skilled in the art will appreciate that it is possible to utilize other dispersing agents known in the art without departing from the scope of the invention.

According to a further embodiment, the filler is selected from the group consisting of china clay and is present in quantity sufficient amount. The term "quantity sufficient" used in reference to the amounts of ingredients is commonly understood in the art to mean the quantity required to make up volume of the composition and is generally readily determined by the persons skilled in the formulation arts. Quantity sufficient can be interchangeably used as "q.s." In a preferred embodiment, the filler is preferably sodium china clay. However, those skilled in the art will appreciate that it is possible to utilize other fillers known in the art without departing from the scope of the invention.

The present invention also provides a process for preparing a water dispersible granular (WG) composition of present invention, said process comprising the steps:

- Milling mixture A with air classifier mill (ACM) that results in powder B.

- Transferring the above powder C in a dough mixer.

- Spraying Triazophos technical to the powder C to get dough D.

- Transferring dough D to extruder by maintaining temperature of extruder below 70°C.

- Starting granulation of the dough D with extruder to obtain granules E.

- Drying granules E at 70^° C The water dispersible granular composition of present invention comprising at least one liquid agrochemically active substance; at least one wetting agent; and at least one first agrochemically acceptable excipient, wherein the composition is prepared by the process as disclosed above. The novel water dispersible granular composition of the present invention exhibits high dispersibility, suspensibility, increased bio-efficacy, low environmental load, low inhalation toxicity to the applicators, no phyto-toxicity among other advantages which include packing, transportation, storage etc. Most importantly the novel water dispersible granular composition is free from basic problems of sedimentation and stability faced with currently available liquid commercial formulations or triazophos due to inherent characteristics of the active ingredients.

The present invention is more particularly described in the following examples that are intended as illustrations only, since numerous modifications and variations within the scope of the present invention will be apparent to a person skill in the art. Unless otherwise noted, all parts, percentages and ratios reported in the following examples are on a weight basis and all reagents used in the examples were obtained or are available from the chemical suppliers.

Examples

The following examples illustrate the basic methodology and versatility of the present invention. The unit of each value below is "% w/w" i. e. the percentage by weight, relative to the weight of the total solution or composition unless otherwise specified. The compositions contemplated by each of the Examples 1-3 that are tabulated in Table 1 are formulated as a Soluble Liquid (SL) formulation.

Examples 1-3

Table 1: Examples of novel water dispersible granular composition of present invention

*q.s = quantity sufficient

**A.I = Active ingredient

The aforementioned compositions can be formulated as water dispersible granular (WG) composition by the process described in Example 4 below.

Example 4 Process of preparation of water dispersible granular (WG) composition of present invention

The synergistic insecticidal compositions of Examples 1-3 are prepared by the process described hereinafter. All the raw materials were verified for conformance to the laid down individual specifications. The required quantities of raw materials as illustrated in Table 2 below, said process comprising the steps:

- Milling mixture A with air classifier mill (ACM) that results in powder B.

- Transferring the above powder C in a dough mixer.

- Spraying Triazophos technical to the powder C to get dough D. - Transferring dough D to extruder by maintaining temperature of extruder below 70^°C.

- Starting granulation of the dough D with extruder to obtain granules E.

- Drying granules E at 70 C

Table 2: Quantities of the active ingredients and raw materials charged

*A.I = Active ingredient

Example 5 Evaluation of insecticidal effect of the novel water dispersible granular composition of present invention

In the evaluation of insecticidal effect of the novel water dispersible granular composition of present invention, a field trial was conducted on paddy to evaluate the insecticidal control of insects i.e. stem borers, hispa, hoppers and other insect in a mixture, as a foliar application. The mixture was prepared by the process described in the above example. Commercially available compositions of Triazophos (WILPHOS), and Lambda Cyhalothrin (Sunny 5 EC) were diluted with water to the stated concentration of the active compound as per details provided in Table 3. Applications were made with a backpack type sprayer fitted with a pressure regulator and a vertical bar with one hollow cone nozzle. Experiment design was in random blocks with four repetitions, and each plot was measured at area of 25 sq. Mts. The rate of application was 500 1/ha for all the trials. The number of insects (nymph, adults) per hill was assessed 10 days after application (DAA). The impact of novel water dispersible granular formulation of present invention for different insects at different concentrations of Triazophos is tabulated in Table 4 below.

To find out the most effective and economical treatment, the cost-benefit analysis of each treatment was worked out for different treatments. Cost benefit ratio (BCR), defined as the number of times the insecticide control cost was recouped from the value for the increased yield and was calculated as:

Cost benefit ratio = (Gross Return - (Cost of Chemical + Cost of Cultivation)/ (Cost of Chemical + Cost of Cultivation)

Table 3: Treatment details for evaluation of bio-efficacy of novel water dispersible granular composition at different concentration of Triazophos

Particulars Treatment Dose a. i. gm/ha Volume of

formulation (ml)

T, Triazophos 20% WG 200 1000

T₂ Triazophos 20% WG 300 1500

T₃ Triazophos 20% WG 400 2000

T₄ Triazophos 20% WG 500 2500

T₅ Triazophos 20% WG 800 4000

T₆ Triazophos 40% EC 500 1250

Tv Lambda Cyhalothrin 5% EC 12.5 250

T₈ Control ~ ~

**A.I = Active ingredient Table 4: Impact of novel water dispersible granular formulation of present invention for different insects at different concentrations of Triazophos

*DAA: days after application

#SEm ±: Standard Errors of Means

'CD: Critical difference

The aforementioned trial results indicate that the Triazophos 20% WG composition of present invention is most effective against all the target insect-pest and better crop condition at treatment level of T₂. From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitations with respect to the specific embodiments illustrated is intended or should be inferred. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the following claims.

Claims

1. A novel water dispersible granular composition (WG), comprising:

- at least one liquid agrochemically active substance;

- at least one wetting agent acting as wetting agent; and

- at least one agrochemically acceptable excipient.

2. The novel water dispersible granular composition (WG) as claimed in claim 1, wherein the liquid agrochemically active substance is an insecticide.

3. The novel water dispersible granular composition (WG) as claimed in claims 1 and 2, wherein the liquid agrochemically active substance is an insecticide and preferably triazophos.

4. The novel water dispersible granular composition (WG) as claimed in claims 1 to 3, wherein triazophos is present in an amount of 15-20% w/w.

5. The novel water dispersible granular composition (WG) as claimed in claims 1 to 4, wherein the wetting agent is selected from the group consisting of acrylate polymer alone or in combination thereof.

6. The novel water dispersible granular composition (WG) as claimed in claims 1 to 5, wherein the wetting agent is preferably sodium salt of styrenated methyl acrylate.

7. The novel water dispersible granular composition (WG) as claimed in claims 1 to 6, wherein the wetting agent is present in an amount of 2-5% w/w.

8. The novel water dispersible granular composition (WG) as claimed in claims 1 to 7, wherein the excipients are selected from the group comprising of surfactants, absorbents, carriers, dispersing agents, fillers etc. alone or in combination thereof.

9. The novel water dispersible granular composition (WG) as claimed in claims 1 to 8, the surfactant is selected from the group consisting of blend of aldehyde condensate, naphthalene sulphonic acid and sulphosuccinate alone or in combination thereof.

10. The novel water dispersible granular composition (WG) as claimed in claims 1 to 9, wherein the surfactant is preferably a blend of modified naphthalene sulphonate formaldehyde condensate, butylated naphthalene sulphonic acid and dioctyl sulphosuccinate.

11. The novel water dispersible granular composition (WG) as claimed in claims 1 to

10, wherein the surfactant is present in an amount of 8-12% w/w.

12. The novel water dispersible granular composition (WG) as claimed in claims 1 to

11, wherein the absorbent is selected from the group consisting of silicates alone or in a combination thereof.

13. The novel water dispersible granular composition (WG) as claimed in claims 1 to

12, wherein the absorbent is preferably ammonium precipitated silica.

14. The novel water dispersible granular composition (WG) as claimed in claims 1 to

13, wherein the absorbent is present in an amount of 10-20% w/w.

15. The novel water dispersible granular composition (WG) as claimed in claims 1 to

14, wherein the carrier is selected from the group consisting of sulphates alone or in combination thereof.

16. The novel water dispersible granular composition (WG) as claimed in claims 1 to

15, wherein the carrier is preferably ammonium sulphate.

17. The novel water dispersible granular composition (WG) as claimed in claims 1 to

16, wherein the carrier is present in an amount of 25-35% w/w.

18. The novel water dispersible granular composition (WG) as claimed in claims 1 to

17, wherein the dispersing agent is selected from the group consisting of lignosulphonates alone or in combination thereof.

19. The novel water dispersible granular composition (WG) as claimed in claims 1 to

18, wherein the dispersing agent is preferably sodium lignosulphonate.

20. The novel water dispersible granular composition (WG) as claimed in claims 1 to

19, wherein the dispersing agent is present in an amount of 3-5% w/w.

2 1 . t he novel water dispersible granular composition (WG) as claimed in claims 1 to 20, wherein the filler is selected from the group consisting of china clay alone or in combination thereof.

22. The novel water dispersible granular composition (WG) as claimed in claims 1 to 21 , wherein the filler is preferably sodium china clay.

23. The novel water dispersible granular composition (WG) as claimed in claims 1 to 22, wherein the filler is present in quantity sufficient.

24. A process for preparing a novel water dispersible granular (WG) composition as claimed in claim 1, wherein process comprises: - Charging all ingredients except Triazophos technical in a pre-blender and mixing for 30 minutes to get a mixture A.

- Milling mixture A with air classifier mill (ACM) that results in powder B.

- Transferring the above powder C in a dough mixer.

- Spraying Triazophos technical to the powder C to get dough D.

- Starting granulation of the dough D with extruder to obtain granules E.

- Drying granules E at 70 C