|Title of Invention||
A STORAGE STABLE PESTICIDE FORMULATION CONTAINING AZADIRACHTIN
|Abstract||The present invention relates to a storage stable pesticide formulation comprising from 1 % to 60% by weight of at least one vegetable oil, 20% to 50% by weight of at least one non-ionic surfactant, and a neem seed extract containing 0.03% to 5% by weight of azadirachtin and providing storage stability by which at least 90% by weight of the azadirachtin originally present remains after 1 year of storage at 25°C I in a sealed container or at accelerated aged test of28 days at 54°C.|
Background of the Invention
The present invention relates to storage stable pesticide formulations containing azadirachtin.
Extracts of various parts of the name tree such as leaves, bark, seeds etc. have been long known to have insecticide activity. The seed kernel in particular processes the most active limuloids, such as Azadirachtin A and B and structurally related compounds such as Azadirachtin D, E, F, H, I, K, and the like, along with nimbi, salami, azadiradione and the like. All the natural azadirachtins have been reported a very high growth disturbing activity against Epilating harvests, with m the range of 0.3 to 2.8 ppm. More than 100 torpedoed metabolites are reported from the name seed or fruit of the name 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 need seed extracts obtained after removal of liquid components are normally contain about 20-45% of Azadriachtin A and B and have been shown to be potent insect growth regulator and fledge 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 azadirachtm. Studies on the degradation of azadriachtin A in various solvents for 25 days at 29 ±
indicated that 50% of degradation of azadirachtin A in methanol and acetone, 75-80% in methyiene 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. U.S. 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. U.S. Patent No. 4,946,681 reports greater stability for azadirachtin in solutions of paretic solvents containing less than 2-5% of water. U.S. Patent No. 5,001,146 indicates that azadirachtin stability is improved adjusting the concentration of polar paretic solvent to at least 50% by volume and by decreasing water content to less than 15% by volume.
Moreover, U.S. Patent Ko.5,001,146 further indicates that azadirachtio stability depends upon the type of solvent employed, and that stability requires storage in certain enumerated parotid and alcohol solvents. U.S.PatentNo. 5,736,145 reports a storage stable aqueous composition containing azadirahtin A and U. S. 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.
U.S. Pat. No.5,352,697 describes the enhancement of stability of azadirachtin in solution by the presence of an peroxide, preferably an deoxidized vegetable oil. All these methods describe the enhancement of azadirachtin containing extracts m the liquid form prepared from enemy seed kernel with organic solvents.
European Patent No. 9216109 describes making an extract of name seed in solid form with greater stability. The stability of azadirachtin in enema extracts is reported to be improved by removing the lipid impurities from extract (Indian Patent Application No. 1855/MAS/97). U.S. 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 2% surfactant and 99% of solid diluents has been claimed as a stable
bio-control agent by retention al at least 75% of azadirachtin after 2 weeks of storage at 54” C. Such a formulation may be used as a and wet table powder, but the efficacy of azadirachtm in such vehicular formulations is not practically reported.
Anodize formulation is a solid form of name seed extract prepared from the kernel of enema seed as per the methods described in U.S.Patent No. 5,695, 763, European patent No. 579,624 and IN 181,845. The product is quite stable with respect to its active ingredients viz. azadirachtin A, B, nimbi, salami and the like.
Though, various extracts with stable azadirachtin have been reported, stability of azadirachtm 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 gradients in liquid formulations and the associated problem of instability in such fornications 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.
Accordingly, there is a need to develop environmentally safe pesticide formulations which contain azadirachtin and which are further storage stable and economical.
The aim of the present invention is to develop a delivery system for azadirachtin containing name seed extracts, free from any organic solvent, less expensive and as more stable and efficacious mollifiable concentrate.
Various plant oils such as need oil, castor oil, acorns oil, sesame oil etc. are known to be used as additives for enhancing the efficacy of formulations by synergism. These oils may be the ideal substitutes to organic solvents but at higher concentrations these may cause phytotoxicity and instability to the active ingredients of the formulation. The advantage of sesame oil as a natural synergist to synthetic pyrediroid insecticides has been demonstrated. The possibility of increasing the efficacy of various enema seed
extracts against different insects by addition of sesame oil has been examined. It has been reported that lecithin II with sesame oil has improved the effect of a name extracts obtained from methyl-tertiary-butyl-ether in achieving higher mortality of Acyrthosiphon possum and Aphis fabled. It is also reported that addition of sesame oil to commercial name formulations containing azadirachtin has increased insecticide efficacy of the formulations against adult aphids, Aphis carcinoma. While these reports indicate that sesame oil could enhance the efficacy of enema extracts, to the best of our knowledge, no one has studied its effect on the stability of most active compounds of enema extracts such as azadirachtins which is an important aspect for development of commercial formulations.
The present invention provides a composition of a name seed extract and sesame oil, free from any organic solvents, with better efficacy and storage stability for azadirachtins.
All of the patents and publications mentioned throughout this application are incorporated herein as in their entirety.
SUMMARY OF THE INVENTION
A feature of the present invention is to provide a storage stable pesticide formulation which avoids the use of organic solvent.
A further feature of the present invention is to provide a pesticide formulation which is storage stable.
An additional feature of the present mentions is to provide a pesticide formulation which contains primarily all natural components and is an effective pesticide formulation. Additional features and advantages of the present invention will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention will be realized and obtained by means of the elements and combinations particularly pointed out in the written description and appended claims.
To achieve these and other advantages, and in accordance with the purpose of the present mention, as embodied and broadly described herein, the present invention relates to a storage stable pesticide formulation contemning at least one vegetable oil, at least one n on ionic surfactant, and azadirachtin.
The present invention further relates to a storage stable pesticide formulation containing at least one vegetable oil, at least one surfactant, which is preferably non-ionic, and a neem extract which contains at least azadirachtin.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present invention, as claimed.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The present invention relates to a pesticide formulation containing at least one vegetable oil, at least one surfactant, and azadirachtin, which is preferably present in the form of a need extract.
The azadirachtin is preferably an azadirachtin A and/or B. Other forms of azadirachtin can be used alternatively or in combination with the preferred azadirachtin. For instance, other structurally related azadirchtin can be used such as D, E, F, H, I and/or K, and the like. The name seed extract which can be present in the pesticide formulation contains at least azadirachtin. Further, the name seed extract can contain nimbi, salami, azadiradione, and the like.
The amount of azadirachtin present in the pesticide formulation can be any amount effective to have insecticides activity, such as, but not limited to, reducing or eliminating insecticidal damage to trees and/or
crops. Preferably the amount of azadirachtm present m the pesticide formulation is from 0.03 weight % to 5.0 weight % based on the weight of the pesticide formulation, and more preferable from 0.03% to 1.0 weight % based on the weight of the pesticide formulation. In terms of the neem seed extract, the neem seed extract is preferably present in an amount, such that from 0.03 to 5.0 weight % of azadirachtin is present in the pesticide formulation. Most preferably, the azadirachtin present in the pesticide formulation is from 0.03 to 5.0 weight % azadirachtin A and/or B.
The method for producing the azadirachtin, which is storage stable, is described in U.S. Patent No. 5,695,763. 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 azadirchtin 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 is used for preparation of high azadirachtin containing extracts. The azadn-achtin can also be recovered by the techniques set forth in U.S. Patent Nos. 4,556,562 and 5,124, 349 and other conventional methods.
With respect to the vegetable oil, and preferably the sesame seed oil, is about 60 weight % or less by weight of the pesticide formulation and preferably is from about 20 weight % to about 48 weight % sesame oil by weight of the pesticide formulation.
With respect to the surfactant, the surfactant is preferably a non-ionic surfactant. Most preferably, the surfactant is an ethoxylated sorbitan esters and even more preferably is apolyoxyethylene sorbitan trioleate such as polyoxyethylene 20 sorbitan trifoliate which is sold under the trade name Teen® 85 which is a non-ionic surfactant manufactured by ICI Limited. The surfactant can be present m any amount as long as the azadirachtin and vegetable oil are uniformly dispersed throughout the pesticide formulation and the amount of surfactant does not significantly hinder die stability and insecticidal activity of the active ingredients. Preferably, the surfactant is present in an amount of from about 20 weight % to about 50 weight %, by weight of the pesticide formulation, and most preferably is present in an amount of from about 40% to about 55% by weight.
These pesticide formulations can be prepared by conventional mixing techniques such as by adding the ingredients together and mixing the ingredients with conventional mixers. Preferably, the surfactant is added to the neem extract containing the azadirachtin. Then, sesame oil is added afterwards and the ingredients are mixed together to the extent that they are distributed uniformly throughout the formulation.
We have observed that the behavior of azadirachtin at real time and the accelerated conditions (especially at 54® C) is quite different as the data generated on stability of azadirachtin A in a formulation indicated that the accelerated storage test overestimates the degradation of azadirachtin A at real time conditions. Under the accelerated storage test conditions (at 54® C) the degradation of azadirachtin A was observed to be 66% after 14 days but under the real time at 20® C a degradation of “proximately 0.9% per month was observed with a total degradation of 11% per year. Thus, the formulation (Formulation III, Example 2) as per the present invention can expected to have higher stability as it recorded only 35.35% degradation in 14 days at 54® C.
The pesticide formulations of the present mentions are preferably quite storage stable and thus very beneficial for commercial applications. Preferably, the pesticide formulations of the present invention have a stability such that at least 90% by weight of the azadirachtin originally present remains after 1 year of storage at 25® C
in a sealed container. Most preferably, the pesticide formulations of the present invention are storage stable to the extent that at least 90% by weight of the azadirachtins originally present remain after 1 year of storage at room temperature in a sealed container.
The ability of the pesticide formulations of the present invention to contain no organic solvents and yet be storage stable has advantages over commercially available formulations since in many specialty application, the use of organic solvents is not recommended.
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
1. Preparation of Azadirachtin formulations
The dry neem seed extracts of azadratchtin 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 azadvachtin (A, 25-35% and B, 5-9%). One of the samples containing 40.26% of azadirachtin (A, 31.51% and B, 8.75%) was used in the preparation of the following formulations. Analysis of azadriachtin content of all the samples and formulations were by HPLC, using an external analytically pure azadirachtin standard.
Formulation I: 3.103 g of the neem seed extract powder containing azadu'achtin was added slowly to a well stirred liquid of Tweed 85 (96.90 g) taken in a conical flask and stirring was continued for 30 minutes until a clear homogeneous mixture is obtained. The azadirachtin content of the formulation was found to be 1.24%.
Formulation II: 3.1 g of the neem seed extract powder containing azadirachtin was added slowly to a well stirred liquid of Tween 85 (72.00 g) taken in a conical flask and stirring was continued for 30 minutes until the solid is completely dissolved. To this added sesame oil (25.04 g) and the contents were mixed thoroughly to obtain a clear homogeneous formulation. The azadirachtin content of the formulation was found to be 1.27%.
Formulation III: 3.15 g of the neem seed extract powder containing azadirachtin was added slowly to a well stirred liquid of Tween 85 (48.86 g) taken in a conical flask and stirring was continued for 45
minutes until the solid is completely dissolved. To this added sesame oil (48.0 g) and the contents were stirred thoroughly to obtain a clear homogeneous formulation. The azadirachtin content of the formulation was found to be 1.24%.
Formulation IV: 3.11 g of the neem seed extract powder containing azadirachtin was added slowly to a well stirred liquid of Tween 85 (22.03 g) taken in a conical flask and stirring was continued for about 60 minutes until the solid is completely dissolved. To this added sesame oil (75.03 g) and the contents were stirred for 20 minutes. The formulation found to be no homogeneous at this proportion of Tween 85 and Sesame oil and the layers of surfactant and oil were separated upon stand. The individual layers thus obtained were separated with the help of a separating funnel. The sesame oil fraction found to contain 0.26% of azadirachtin was used for evaluation of stability of azadirachtin in sesame oil.
Formulation V: 3.11 g of the neem seed extract powder containing azadirachtin was added slowly to a well stirred solution of Tween 85 (32.2 4 g) and cyclohexanone (32.36 g) taken in a conical flask and stirring was continued for 30 minutes until the solid is completely dissolved. To this added neem oil (32.20g) and the contents were stirred thoroughly to obtain a clear homogeneous formulation. The azadirachtin content of the formulation was found to be 1.25%.
2. Stability of Azadirachtin formulations containing Sesame oil
The stability of formulations MV obtained by Example 1 was studied at 54 Each of the samples (20 g) was taken into a sealed glass vial and kept in the oven at 54 for 28 days. Samples were taken out every week and analyzed for their azadriachtin content by HPLC. The results (Table 1) indicates higher stability for azadirachtin in formulation III compared to rest of the formulations.
3. Antecedent effect of Azadirachtm formulations containing sesame
oil and neem oil against Spodoptera literal
Formulations I-III and V were tested for their antecedent effect against the insect Spodoptera literal. The castor leaf disks were cut and dipped in 30 and 50 ppm of azadirachtin concentrations of different formulations and offered to 5 day old S. Jitters larvae. The
experiments were replicated thrice with ten insects per treatment per replication. The percentage antifeedancy was assessed agiler 2, 5, 10 and 14 days after treatment by calculating the difference in leaf area consumed in the treated and control group. The formulation with 48% of sesame oil showed higher antecedent activity.
Mean values in a row followed by the same alphabet are statistically not significant (p
4. Growth inhibition effect of Azadirachtin formulations containing sesame oil and neem oil against Spodoptera literal
The insect growth inhibition activity of formulations I - III and IV was against the insects. literal. The castor leaves treated with 30 and 50 ppm of azadirachtm concentration of various formulations were offered to 5 day old S. literal 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 containing 48% of sesame oil shown highest growth inhibitory activity against the insect Spodoptera literal (Table 3).
Mean values in a row followed by the same letter are statistically not significant (p 5. Mortality effect of Azadirachtin formulations containing sesame oil
and neem oil against Spodoptera litura
The insecticidal (mortality) activity of azadirachtin formulations (I -III and V) was studied against the insect Spodoptera litura For mortality test, castor leaves treated with 30 and 50ppm concentrations of azadirachtin of various formulations 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 48% of sesame oil showed highest mortality against the sect Spodoptera litura.
Mean values in a row followed by the same letter are statistically not significant (p
1. A storage stable pesticide formulation comprising from 1% to 60% by weight of at
least one vegetable oil, 20% to 50% by weight of at least one non-ionic surfactant, and a need seed extract containing 0.03% to 5% by weight of azadirachtin and providing storage stability by which at least 90% by weight of the azadirachtin originally present remains after 1 year of storage at 25in a sealed container or at accelerated aged test of28daysat54°C.
2. The pesticide formulation as claimed in claim, wherein said vegetable oil is
3. The pesticide formulation as claimed in claim 1, wherein said vegetable oil contains
less than 1% by weight free fatty acid based on the weight of the vegetable oil.
4. The pesticide formulation as claimed in claim 1, wherein said azadirachtin is
present in an amount of 0.1 to 1.0 weight %.
5. The pesticide formulation as claimed in claim 1, wherein said azadirachtin is
azadirachtin A or azadirachtin B or both.
6. The pesticide formulation as claimed in claim 1, wherein said surfactant is a
polyoxyethylene Serbian trifoliate.
7. The pesticide formulation as claimed in any one of the preceding claims, wherein
said formulation is substantially free of organic solvents.
|Indian Patent Application Number||507/MAS/2000|
|PG Journal Number||38/2007|
|Date of Filing||30-Jun-2000|
|Name of Patentee||M/S. E. I. D. PARRY (INDIA) LIMITED|
|Applicant Address||145 DEVANAHALLI ROAD, BANGALORE 560049,|
|PCT International Classification Number||A01N 65/00|
|PCT International Application Number||N/A|
|PCT International Filing date|