|Title of Invention||
A STABLE SOLID PESTICIDE COMPOSITION
|Abstract||This invention relates to stable solid pesticid composition.It consists of neem seed extracts containing azadiractins and at least one saccharide.|
The present invention relates to a stable pesticide composition containing neem seed extracts such as azadirachtins.
Extracts of various parts of the neem tree (Azadirachta india A. Juss) such as leaves, bark, seeds etc. have been known to have insecticidal activity. The seed kernel in particular posses the most active limonoids, such as Azadirachtin A and B and structurally related compounds such as Azadirachtin D, E, F, H, I, K, and the like, along with nimbin, salannin, azadiradione and the like. All the natural azadirachtins have been reported a very high growth disturbing activity against Epilachna vanvestis, with LC50s in the range of 0.3 to 2.8 ppm (H.Rembold and I Puhlmann, 1995). More than 100 terpenoid metabolites are reported from the neem seed/fruit of the neem tree. Various methods have described to extract these active components in the crude or semi crude forms to be used in commercially acceptable vehicles in the form of liquid and solid formulations. The crude neem seed extracts obtained after removal of lipid components are normally contain about 20-45% of Azadriachtin A and B and have been shown to be potent insect growth regulator and feeding deterrent and form as potential active ingredients in commercial pest control formulations. These active molecules, however, are rather large and complex, and having acid and base sensitive functional groups they tend to be unstable in these vehicles, thus posing a major limitation for commercial application of these extracts.
So far, azadirachtin has been widely formulated in liquid forms to be applied as an emulsion or solution to agriculture crops. Various organic solvents and other inorganic additives have been used as carriers in order to make a cost effective and efficacious delivery system. The use of such carriers is rather limited, however, since many solvents are deleterious to the stability of azadirachtin. Dureja (1999) has studied the degradation of azadriachtin A in various solvents for 25 days at 29+/- 1°C. The results indicated 50% of degradation of azadirachtin A in methanol and acetone, 75-80% in methylene chloride, carbon tetrachloride and chloroform and about 85% in ethanol and water.
Storage-stable azadirachtin formulations and methods of preparing stable azadirachtin compositions have been proposed. US Patent No.4,556,562 reports that the stability of azadirachtin in ethanol emulsions increased by diluting the concentration of azadirachtin to between 2000 and 4000 ppm and adjusting the pH to between 3.5 and 6.0. US Patent No.4,946,681 (Walter) reports greater stability for azadirachtin in solutions of aprotic solvents containing less than 2-5% of water. US Patent No.5,001,146 indicates that azadirachtin stability is improved adjusting the concentration of polar aprotic solvent to at least 50% by volume and by decreasing water content to less than 15% by volume. Moreover, US Patent No.5,001,146 further indicates that azadirachtin stability depends upon the type of solvent employed, and that stability requries storage in certain enumerated aprotic and alcohol solvents. US Patent No. 5,736,145 reports a storage stable aqueous composition containing azadirahtin A and US Patent No.5,827,521 indicates a stable azadirachtin formulation containing aliphatic
dihydroxylated alcohols of more than 80% by volume and optionally with sunscreens and antioxidants.
US Patent No. 5,3 52,697 describes the enhancement of stability of azadirachtin in solution by the presence of an epoxide, preferably an epoxidized vegetable oil. All these methods describes the enhancement of azadirachtin containing extracts in the lqiuid form prepared from need seed kernel with organic solvents.
European Patent No.579,624 describes making an extract of neem seed in solid form with greater stability. The stability of azadirachtin in neem extracts is reported to be improved by removing the lipid impurities from extract (Indian patent Application No.l855/MAS/97). US Patent No. 5,635,193 reports that an azadirachtin containing solid is stable by limiting moisture and volatile polar solvents to less than 1% and 5% respectively. A formulation containing 0.05% to 12% surfactant and 99% of solid diluent has been claimed as a stable bio-control agent by retention of at least 75% of azadirachtin after 2 weeks of storage at 54°C.
Such formulation may be used as a dust and wettable powder, but the efficacy of azadirachtin in such vehicular formulations is not practically reported.
Another formulation is a solid form of neem seed extract prepared from the kernel of neem seed as per the methods described in U.S. Patent No. 5,695, 763, European patent No. 5 79,624, and IN 181,845. The product is quite stable with respect to its active ingredients viz. azadirachtin A, B, nimbin,. salannin and the like.
Though, various extracts with stable azadirachtin have been reported, stability of azadirachtin in a formulated state is still a concern. Azadirachtin is highly unstable in various surfactants, organic solvents, and in different combinations of solvent and surfactant in liquid formulations which is a serious limitation for the development of a shelf stable commercial product.
Normal pesticide formulations contain various solvents made mostly from petroleum, and there is a concern that usage of such solvents in specialty pesticide formulations, especially meant for organic farming, veterinary application, and the like, is discouraged. The use of such solvents, even at a lower rate demands large amounts of surfactants and other additives which makes the cost of the formulations high.
The use of a broader range of ingredients in liquid formulations and the associated problem of instability in such formulations is also a serious concern for the commercial success of azadirachtin containing crop protection agents. Accordingly, there is still a need for a formulation containing simple, safe, and cost effective vehicles which yet provides stable and efficacious products.
As noted above the pesticidal effect of neem active compounds such as azadirachtins
is mostly through insect growth regulation, ffifiibition, antifeedant, ovicidal
and other physiological effects and is normally slow compared other synthetic pesticides which result in immediate knockdown. Hence, there is a need to identify ways and methods to enhance the efficacy of neem extracts for their wide spread acceptance as a pesticide.
Accordingly, there is a need to develop environmentally safe pesticide formulations which contain azadirachtin and which are further storage stable, efficacious and economical.
The aim of the present invention is to develop a stable solid composition of azadirachtin containing neem seed extracts, free from any organic solvent which is completely soluble in water and is efficacious at a dosage lower than the normal desired dose of azadirachtin containing neem seed extracts for pest control.
Another feature of the present invention is to provide a neem seed extract in solid form which is stable and flowable.
Additional featureof the present invention is to provide a neem seed extract in efficacious solid form which is water soluble and mis is quite easily used to control insect pests.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein the present invention relates to a solid pesticide composition comprising neem seed extract comprising azadirachtin and at least one saccharide.
It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are intended to provide former explanation of the present invention, as claimed.
The present invention relates to pesticide composition containing neem seed extracts, such as azadirachtins. In particular, the present invention relates to a solid pesticide composition which contains neem seed extract and at least one saccharide.
Preferably, the neem seed extract contains at least azadirachtin. Further, the neem seed extract can contain nimbin, salannin, and/or azadiradione, and the like. The azadirachtin that is preferably present in the neem seed extract can be one or more types of azadirachtin compounds and are more preferable azadirachtin A and/or B but can also be or include structurally related compounds such as azadirachtin D, E, F, H, I and/or K, and the like.
The neem seed extract is present in the pesticide composition in an amount effective to reduce or eliminate insect activity, such as on vegetation. Preferably, the neem seed extract containing from about 0.03 to about 5.0 weight %, and more preferably from about 0.1 to about 1.0 weight % based on the weight of the pesticide composition. Generally, the azadirachtin will be present in the neem seed extract in an amount of from about 20% to 50% by weight of the neem seed extract though other amount below 20% and above 50% are possible.
Most preferably, from about 20% to about 50% of the neem seed extract, by weight of the neem seed extract is an azadirachtin A and/or B.
The neem seed extract can be obtained following the process recited in U:S. Patent No. 5,695,763 which is incorporated in its entirety by reference herein In general, the azadirachtin is recovered preferably from the seeds of a neem tree by crushing the seeds and then extracting the azadirachtin and other active ingredients from the crushed seeds with water. The extraction of azadirachtin and other active ingredients from the water is accomplished using a non-aqueous solvent which is not miscible with water and has a high solubility of azadirachtin than water, or by using a surfactant having a turbidity temperature between 20° and 80° C. The concentrated azadirachtin is then recovered from the second extracting solution. The azadirachtin containing solution is then concentrated to produce an azadirachtin concentrate which is added to a liquid hydrocarbon, thus forming an azadirachtin precipitate that is then recovered for use in pesticide formulations. The method described in Indian Patent No. 181,845 which also used for preparation of high azadirachtin containing extracts. The azadirachtin can also be recovered by the techniques set forth d U.S. Patent Nos. 4,556,562 and 5,124,349 and other conventional methods.
The solubility of such neem extracts (Aza 20-50%) in water is less than 0.1% which can yield 200 -500 ppm of aza in solution. However, the recommended dose of azadirachtin for control of various pest control in the field is about 30 ppm which can be prepared by dissolved 0.06 - 0.15 g of extracts in 1000 ml of water. But handling such a small quantities by the user is cumbersome which can be avoided by formulating/diluting the concentrated extracts in inert carriers. Several diluants such as talc, stealite, soap stone, pyrophyllite and yellow talc, kaolin etc. are commonly used in compositions and formulations but are unsuitable for azadirachtin based formulations as they may degrade azadirachtin because of their nature of acidity and alkalinity. More particularly they are not suitable for a water soluble type of formulation. In search of alternate diluants, we have studied various sugars for their suitability in formulation in terms of stability and other properties of a ready to use formulation. One of the major problems in using sugars, as observed in other pesticide formulations, is formation of cake type mass of the formulated product on storage due to hygroscopic nature of these substances. However, no such problem is encountered with neem seed extracts which may be due to anticaking properties of the fine powdery extracts. A wetting agent and with or with out a sticker are necessary in order to make the formulation to be used effectively in the field. Two of the compositions (1.25% and 6.12% Aza) of neem seed extracts with sucrose (87.26%)
and methyl cellulose (10%) were prepared and evaluated their stability at accelerated
temperature . azadirachtin
/ at 54 C The results indicated that the / . is more stable in the formulation
than in the neem seed extract which shows that these saccharides are imparting
additional stabilizing effect on azadirachtin in the formulated form. In addition to the
enhancement of stability, to our surprise the formulation has shown higher pesticidal
activity particularly imparting early mortality of the insect larvae.
With respect to the saccharide, one or more saccharides can be present in the pesticide composition. Preferably at least two different saccharides are present in the pesticide composition. More preferably, at least one saccharide is a di-saccharide and at least one other saccharide is a polysaccharide. Even more preferably, the saccharides present in the preferred pesticide composition is at least one di-saccharide and a cellulose derivative, such as methyl cellulose. The mono-saccharide is preferably a simple sugar, such as glucose, fructose, and/or galactose. The saccharide can also be a di-saccharide such as sucrose. Most preferably, the saccharide is a methyl cellulose
and a sucrose. The saccharides are preferably present in an amount of from about 20% to about 99.9% by weight of the composition. Most preferably, this saccharide is present in an amount of from about 80 weight % to about 70 weight %.
Most preferably, the saccharide is a cellulose derivative such as methyl cellulose which is present from about 0.1 to about 20 weight % by weight of the pesticide composition and the disaccharide such as sucrose is present in an amount of from about 0.5% to about 90% by weight of the pesticide composition.
binding If desired, carriers such as conventional / agents such as natural polymers, for
example gum arabic, guar gum, polyvinyl cellulose etc. in the form of powders,
granules or lattices can be used in the compositions to improve the adherence of the
The ingredients forming the pesticide composition may be combined after the
ingredients are intimately ground to a particle size of 10 - 100 \i and mixed together
by blending operations of a mechanical nature and preferably to result in a free
flowing powder. Alternatively the neem seed extracts may be dissolved in a suitable
organic solvent and the solution is combined with saccharides and solvents stripped
off under vacuum. The mixture is then intimately ground to a particle size of 10 -
100 \i and mixed together by blending operations of a mechanical nature. It is
azadirachtin believed that the / present further serves to prevent any caking of the
saccharides in the pesticide composition.
The solid pesticide composition which is preferably in powder form but can be present in other solid forms such as pellets and the like, and is preferably stable for long periods of time. For instance, the solid pesticide compositions of the present invention can maintain at least 90% of the azadirachtins originally present even after four weeks of storage at 54°C in a sealed container. Accordingly, the pesticide compositions of the present invention are storage stable.
More advantageously, the solid pesticide compositions of the present invention can be easily formed into a liquid formulation by introducing the solid pesticide composition into a liquid medium. The amount of medium added to be dissolved and/or dispersed
the solid pesticide compositions is based on the desired concentration, but concentrations such as from about 1% to about 5% of the pesticide composition are possible with the present invention. However concentration of about 0.0065% of the pesticide may be sufficient for most of the applications.
The pesticide compositions of the present invention can also include conventional additives, such as carriers, biocides, anti-foamers and the like.
The pesticides compositions of the present invention can be used in any suitable form, such as, but not limited, to dispersions, suspensions, dusting powders, granules, baits, aerosols, fumigating release devices, powders, pellets and the like.
Accordingly the present invention provides, a stable, solid pesticide composition comprising need seed extract containing azadiractins and at least one saccharide.
Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the present invention being indicated by the following claims and equivalents thereof
EXAMPLES 1. Preparation of Azadirachtin formulations
The dry neem seed extracts of azadraichtin were prepared according to the method described in the Indian Patent No. 181, 845. The samples are pale yellow free flowing powders and normally contain 30-45% of azadirachtin (A, 25-35% and B, 5-9%). One of the samples (I) containing 45.02% of azadirachtin (A, 36.16% and B, 8.86%) was used in the preparation of the following formulations. Analysis of azadriachtin content of all the samples and formulations was by HPLC, using an external analytically pure azadirachtin standard, as per the method described by Kleeberg (1994).
Formulation 1 : 2.74 g of the neem seed extract powder containing azadirachtin (45.02%) is added to 87.26 g of finely powdered sucrose and 10 g of methyl cellulose and mixed thoroughly in a blender for 5 - 10 minutes. The azadirachtin content of the formulation is 1.25% (Aza A 1.01%, Aza B 0.24%).
Formulation 2 : 13.4 g of the dry neem seed extract powder containing azadirachtin (45.02%) is added to 76.6 g of finely powdered sucrose and 10 g of methyl cellulose and mixed thoroughly in a blender for 5 - 10 minutes. The azadirachtin content of the formulation is 6.11% (Aza A 4.93, Aza B 1.18).
2. Stability of Azadirachtin in Solid neem seed extract (I) and its
Formulations 1 and 2
The stability of the neem seed extract (I) and its formulations 1 & 2 obtained by the methods described in Example 1 was studied at 54° C. Each of the samples (20 g) was taken into a sealed glass vial and kept in an incubator at 54° C for 28 days. Samples were taken out every week and analyzed for their azadriachtin content by HPLC. The results (Table 1) indicate higher stability for azadirachtin in formulations 1 & 2 compared to that of neem seed extract (I).
I = Neem Seed extract
1 = Solid neem seed extract(2.74%), Methocel (10%), Sucrose(87.26%)
2 = Solid neem seed extract(13.4%), Methocel (10%), Sucrose(76.6%)
3. Antifeedant efficacy of Neem extract containing Azadirachtin and its formulation containing sucrose against Spodoptera litura
The Solid neem seed extract containing azadirachtin (I) and its formulation 1 were tested for their antifeedant effect against the insect Spodoptera litura. The castor leaf disks were cut and dipped in 10, 30 and 50 ppm of azadirachtin concentrations of each test sample and offered to 5 day old S. litura larvae. The experiments were replicated thrice with ten insects per treatment per replication. The percentage antifeedancy was assessed after 2, 5, 7, 10 and 14 days after treatment by calculating
the difference in leaf area consumed in the treated and control group. The antifeedant effect of both the samples was found almost comparable.
I = Neem Seed extract
1 * Solid neem seed extract(2.74%), Methocel (10%), Sucrose(87.26%)
4. Growth inhibition efficacy of Neem extract containing Azadirachtin and its formulation containing sucrose against Spodoptera litura
The solid neem seed extract containing azadirachtin (I) and its formulation 1 were tested for their growth inhibition effect against the insect Spodoptera litura. The castor leaves treated with 10, 30 and 50 ppm of azadirachtin concentration of various formulations were offered to 5 day old S. litura larvae. The experiments were conducted using ten insects per treatment and replicated thrice. Growth inhibition was assessed on 2, 5, 7, 10 and 14th day after treatments by weighing the larvae and the mean weights for each treatment group were expressed as a percentage of controls. The formulation 1 containing sucrose shown prolongation of larval stages up to 14th day compared to neem seed extract (Table 3).
I = Neem Seed extract
1 = Solid neem seed extract(2.74%), Methocel (10%), Sucrose(87.26%)
*Insectes entered into pupation stage
5. Efficacy of Neem extract containing Azadirachtin and its formulation containing sucrose against mortality of Spodoptera litura
The insecticidal (mortality) activity of the Solid neem seed extract containing azadirachtin (I) and its combination with sucrose (1) was studied against the insect Spodoptera litura. For mortality test, castor leaves treated with 10, 30 and 50ppm concentrations of azadirachtin of test samples, I and 1, were offered to 5 day old S. litura larvae. The experiments were replicated thrice with 10 insects per treatment per replication. The percentage mortality was assessed after 5, 7, 10 and 14th day after treatment. The efficacy data (Table 4) indicates that the formulation containing sucrose showed higher mortality even at 10 ppm of Aza against the insect Spodoptera litura.
1. A stable, solid pesticide composition comprising neem seed extracts containing azadiractins and at least one saccharide.
2. The composition as claimed in claim 1, containing 0.03 to 5.0% by weight of neem seed extract containing azadirachtins based on the weight of the pesticide composition.
3. The composition as claimed in claim 1, wherein said neem seed extract contains 20 to 50% by weight of azadirachtins.
4. The composition as claimed in claims 1 to 3 wherein said neem seed extract contains azadirachtin A and/or B.
5. The composition as claimed in claim 1, wherein said composition contains at least two saccharides.
6. The composition as claimed in claims 1 to 5, wherein at least one said saccharide is a di-saccharide and at least said other saccharide is a polysaccharide.
7. The composition as claimed in claims 1 to 6, wherein said polysccharide is a cellulose derivative such as methyl cellulose.
8. The composition as claimed in any one of the preceding claims wherein the saccharide is a monosaccharide selected from glucose, fructose and/or galactose.
9. The composition as claimed in any of the preceding claims wherein the saccharide is sucrose.
10. The composition as claimed in claim 1, wherein said composition contains 0.1 20% by weight of methyl cellulose and 0.5 to 90% by weight of sucrose.
11. The composition as claimed in any of the preceding claims wherein said composition is in the form of free flowing powder.
12. The composition as claimed in claim 1, wherem said saccharide is a mono-saccharide, a disaccharide, a poly saccharide or mixtures thereof.
13. The composition as claimed in any of the preceding claims wherein said composition contains known binders, additives and carriers.
14. The composition as claimed in any of the preceding claims wherein said composition contains known antifoaming agents and biocides.
15. The composition as claimed in any of the preceding claims wherein said saccharides are present in an amount of from 20% to 99.9% by weight of said composition.
16. The composition as claimed in claims 1 to 15, wherein said neem seed extract and said saccharides have a particle size of 10 to 100 p..
17. The composition as claimed in claims 1 to 16, wherein said neem seed extract contains 20 to 50% by wt of azadirachtin A. azadirachtin B or mixtures thereof.
18. A stable solid pesticide composition substantially as herein described.
|Indian Patent Application Number||796/MAS/2000|
|PG Journal Number||50/2007|
|Date of Filing||22-Sep-2000|
|Name of Patentee||M/S. E I D PARRY (INDIA)LTD|
|Applicant Address||145 DEVANAHALLAI ROAD(OFF)OLD MADRAS ROAD,BANGALORE 560 049.|
|PCT International Classification Number||A01N 25/00|
|PCT International Application Number||N/A|
|PCT International Filing date|