BACKGROUND OF THE INVENTION Field of the invention

The invention relates to a non-toxic composition comprising at least one acyclic organosiloxane compound in an aqueous based system for killing, controlling and repelling mosquitoes which annoy humans and animals. The invention further relates to a process of preparing the composition and a method of application of the composition.

Description of the related art

Insects such as mosquitoes are not only bothersome to humans and animals, but are also potential vectors of several diseases in humans such as malaria, dengue sad yellow fever. Various insect controlling compositions have been developed which are capable of eradicating or controlling pests such as mosquitoes. Some examples include

Djchlorodiphenyltrichlorocthanc (DDT), organochlorides such as <jyclodienes and organophosphate compounds. However, the use of these compounds has been restricted due to the toxicity exhibited by these compounds. Furthermore, these prior art compounds are nonbiodegradable and hazardous to the health of the population.

Another group of compounds that have been used in the prior art comprise synthetic pyrethroids. Though pyrethroids were initially effective, mosquitoes have now developed resistance against their use and as a result, these compounds are increasingly unsuitable for effectively controlling the mosquitoes. Hence, these compounds are now required to be administered in larger doses to achieve the desired effect. Further, the pyrethroids are also suspected to be highly carcinogenic, teratogenic and mutagenic. Therefore, larger doses of pyrethroids are undesirable due to the deleterious effect observed in humans.

Hence, a non-toxic or less toxic means for killing and repelling mosquitoes which are not harmful to humans and animals is desired. Many natural substances such as lemon grass oil, eucalyptus oil, neem oil and citronella oil have been know to repel or kill insects such as mosquitoes but these are found to be effective only for shorter durations. These substances further tend to lose their effectiveness when formulated for human and animal use through refining and processing into lotions, oils, sprays and other substances.

Many silicon-containing compounds are considered to be biologically inert. US 2988473 discloses that the effectiveness of insecticides containing hydrocarbon oil can be increased by the incorporation of a small amount of a liquid condensation product of an organo-silieon oxide compound.

US 4155995 discloses the use of small amounts of a dialkyl poiysiloxane and an ethoxylated monoalkyl phenyl to increase the effectiveness of petroleum oil comprising mosquito toxicants.

US6566348 and US4654328 disclose cyclic poiysiloxane compositions suitable for controlling animal pests, such as arthropods, preferably insects and arachnids and the like pests in agriculture. However, it has been observed that the control of pests and insects with the use of these compositions is not satisfactory Hence, there is a need to develop an effective, non-toxic composition comprising inert substances and / or naturally occurring substances which are capable of providing long-term control and eradication of mosquitoes which attack, harm or annoy humans and animals and wherein the composition is also highly eco-friendly. There is also a need to develop composition mosquito control which is highly safe and non-toxic to humans and other animals. There is a further need to develop a composition which acts as a larvicide, shows a good pupicidal activity and can be applied to mosquito breeding sites, stagnant water and water tanks for effectively controlling the mosquitoes in all stages of their life cycle.

SUMMARY OF THE INVENTION

The invention relates to a composition for killing, controlling and repelling mosquitoes comprising an effective amount of at least one acyclic organosiloxane compound in an- aqueous based system.

The invention further relates to a process of preparing a composition for killing, controlling and repelling mosquitoes comprising: a. adding an effective amount of at least one acyclic organosiloxane compound in water to obtain a mixture; and, b). stirring the mixture for about 3- 5 minutes in ambient conditions to obtain a homogenous composition.

The invention further relates to a method of application of the non-toxic composition for killing, controlling and repelling mosquitoes which annoy humans or animals.

DETAILED DESCRIPTION OF THE INVENTION

In describing the embodiments of the invention, specific terminology is resorted for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.

The invention relates to a non-toxic composition for killing, controlling and repelling mosquitoes. · The composition comprises an effective amount of at least one acyclic organosiloxane compound in an aqueous based system.

According to an embodiment, the organosiloxane compound can be a modified polysiloxane compound. The modified polysiloxane compound can be selected from a group consisting of at least one of: a. hydroxyl alkyl disiloxanes; b. polyether modified poiysiloxanes; c. polyester modified poiysiloxanes; d. pplydimethyl siloxane - polyethylene oxide copolymer; e. polyether trisiloxane copolymer; f. polyalkyiene - modified polysiloxane; g. linear trisiloxanes; h. polydiorgancsi!oxane-polyoxyalkylene copolymers; i. polyether-pol siloxane copolymer; j. ABA type silicone compounds; k. Branched silicone compounds; 1. Gemini type silicone compounds; m. Amine based silicone compounds; n. siloxane glycol copolymers; and, o. siloxane-alkylene oxide copolymers.

According to another embodiment, the acyclic organosiloxane compound is polyalkyiene oxide modified heptamethyl trisiloxane. The alkylene group is selected from lower alkyl groups containing upto 5 carbon atoms.

According to yet another embodiment, the polyalkyiene oxide modified heptamethyl trisiloxane compound is polyethylene oxide modified heptamethyl tri-siloxane. According to a further embodiment, the organosiloxane compound can be present in the composition in a range of about 0.001% to 50% on a w/w basis. Preferably, the polysi!oxane compound is present in the composition in a range of about 0.001% to 30% on a w/w basis.

According to an embodiment, the composition further includes a stabilizing agent. The stabilizing agent is selected from a group consisting of at least one of allyloxypolyalkylene glycol methyl ether, polyoxyalkylene monoallyl ether and polyoxyalkylene monoallyl acetate. The alkylene group can be selected from lower alkyl groups containing upto 5 carbon atoms. However, it is possible to utilize other stabilizing agents without departing from the scope of the present invention.

According to an embodiment, the stabilizing agent is present in the composition in a range of about 2% to about 30% on a w/w basis of the total weight of the composition.

According to another embodiment the mixture of the organosiloxane compound and the stabilizing agent can be present in a range of about 0.001% to about 25% on a w/w basis of the total weight of the composition.

According to an embodiment, the aqueous based system comprises water. The aqueous based system can include a mixture of polar or non-polar solvents with water. It can be noted that other aqueous based systems known in the art are well within the scope of the invention.

According to another embodiment, the aqueous based system can be present in a range Cf about 70% to about 99.9% on a w w basis in the composition.

According to another embodiment, the composition can further include at least one aaturally occurring active ingredient. The naturally occurring active ingredient can be selected from neem oil, catnip oil (nepetalactone), lemon grass oil and citronella oil. However, it is possible to include other naturally occurring active ingredients known in the art without departing from the scope of the present invention.

According to yet another embodiment, the naturally occurring active ingredient can be present in a range of about 0.1% to about 5% on a w/w basis in the composition.

According to a further embodiment, the composition can further optionally include at least one synthetic active ingredient selected from one or more of synthetic pyrethroids, N,N-diethyl-3- methylbenzamide (DEET). para-methane-3,8-diol etc. The optional synthetic pyrethroids can include one or more of d-trans aliethrin, beta-cyfluthrin, cypermethrin, deitamethrin, permethrin, prallethrin, tefiuthrin and transfluthrin.

According to a still further embodiment, the synthetic active ingredient can he present in a range of about 0.001% to about 0.25% on a w/w basis in the composition

According to an embodiment, the composition can further optionally include a synergist such as piperonyl butoxide. The synergist can be present in a range of about 0.1% to about 0.5% on a w/w basis in the composition.

According to an embodiment, the composition can further include fragrances. The fragrance can be natural fragrances or synthetic fragrances. The fragrances can include lemon, eucalyptus, citronella oil, lemon grass oil, jasmine, rose, lavender, cedarwood and vanilla. The fragrance can be present in a range of about 0.1% to about 0.3% on a w/w basis of the total weight of the composition.

According to an embodiment, the composition can further include propellants. The propellants are specifically useful when the composition is formulated as an aerosol based spray. The propellants can include kerosene, liquid petroleum gas (LPG), etc. It can be noted that other propellants. known in the art are well within the scope of the invention.

According to a further embodiment, the composition can be formulated as a suspension concentrate^ a homogenous solution or an emusifiable concentrate.

According to an embodiment, the invention further relates to a process of preparing the composition. The process involves adding an effective amount of at least one acyclic organosiloxane compound in one litre of water to obtain a mixture. The mixture obtained is rigorously stirred for about 3-5 minutes in ambient conditions to obtain a homogenous composition.

According to another embodiment, the process further involves adding at least one stabilizing agent to water to obtain the mixture. The stabilizing agent is selected from one of allyloxypolyalkylene glycol methyl ether, polyoxyaikylene monoallyl ether and polyoxyalkylene monoallyl acetate.

According to another embodiment, the process can further comprise adding at least one naturally occurring active ingredient to the mixture. The naturally occuning active ingredient can be selected from neem oil, catnip oil, lemon grass oil and citronella oil.

According to yet another embodiment, the process can further comprise optionally adding at least one synthetic active ingredient to the mixture. The synthetic active ingredient can include synthetic pyrethroids, N,N-diethyl-3-methylbenzamide (DEET) and para-methane-3,S«diol.

The process allows for the preparation of the mosquito killing, controlling and repelling composition comprising at least one acyclic organosiioxane compound in a simple, cost- effective and environmentally safe manner. According to a further embodiment, the invention relates to a method of application of the composition, wherein the composition is applied to flying mosquitoes. The composition functions as an effective house hold insecticide in controlling or repelling mosquitoes. The composition shows good larvicidal or pupicidal activity when applied to mosquito breeding sites, stagnant waters and infected areas. The composition is highly effective in controlling mosquitoes in every stage of its lifecycle. The composition can be in concentrated or diluted form for aerosol, spray, hand held spray for IRS field with or without residual content. It is observed that the composition is non-toxic and is highly safe for the user as well as to the environment. On a commercial scale, the composition is useful as an aerosol based mosquito killer, it is also effective as an indoor residual spray in mosquito and malaria prone a»eas.

The present invention will be illustrated in more detail with reference to the following formulation examples and test examples. As will be recognized by one skilled in the art, these examples are just illustrative and are not meant to be limiting.

A. Formulation Examples

The following examples illustrate the basic methodology and versatility of the invention. Example 1 :

5 gms. of polyalkylene oxide - modified heptamethyttrisiloxane and allyloxypolyethylene glycol methyl ether was added to 1 litre of water in a vessel equipped with a stirrer. The solution was rigourously stirred for about 3-5 minutes at ambient conditions to obtain a homogenous composition.

Example 2: 70 gms of Polyethylene oxide modified heptamethyl tri-siloxane was added to 30 gms of allyloxypolyethylene glycol to obtain a mixture. 5 gms of the mixture obtained was added to about 1 litre of water in a vessel equipped with a stirrer. The solution was rigorously stirred for about 3-5 minutes at ambient conditions to obtain a homogenous composition.

Example 3:

70 gms of Polyethylene oxide modified heptamethyl tri-siloxane was added to 30 gms of allyloxypolyethylene glycol to obtain a mixture. 5 gms of the mixture obtained was added to about 1 litre of water in a vessel equipped with a stirrer. 1 gm of citronella oil and 0.5 gms of lavender fragrance was added to the vessel. The solution was rigorously stirred for about 3-5 minutes at ambient conditions to obtain a homogenous composition.

E. Test Data:

Example 4:

50 Culex female mosquitoes were introduced into a Peet Grady chamber according, to a standard guideline provided by WHO/WHOPES. A composition comprising 10 gms of polyalkylene oxide - modified heptamethyltrisiloxane in 1 litre of water, was introduced into a sprayer. About 4 ml. of the composition was sprayed in the Peet Grady Chamber.

It was observed that within 5-6 seconds the composition exhibited 100% mortality.

Example 5:

50 Culex female mosquitoes were introduced into a Peet Grady chamber according to a standard guideline provided by WHO/WHOPES. A composition comprising 5 gms polyalkylene oxide - modified heptamethyltrisiloxane and allyloxypolyethylene glyvol methyl ether in 1 litre of water, was introduced into a sprayer. About 4 ml. of the composition was sprayed in the Peet Grady Chamber.

It was observed that within 3-5 seconds the composition exhibited 100% mortality. Example 6:

50 Culex female mosquitoes were introduced into a Peet Grady chamber according to a standard guideline provided by WHOAVHGPES. A composition comprising the following constituents was prepared:

About 4 ml. of the composition was sprayed in the Peet Grady Chamber. It was observed that within 4-5 seconds the composition exhibited 100% mortality. Example 7:

A composition comprising 1% w/w mixture of Polyethylene oxide modified heptamethyl tri- siloxane and allyloxypolyethylene glycol in 100 ml. of water was prepared.

No. of lar/a per test: 10

The efficacy of the composition was tested by varying the concentration of the composition, a. Concentration: lg in 100 ml:

Table 1:

Species Test Control

Hours Hours

0.5 1 2 4 6 8 24 0.5 1 2 4 6 8

Aedes aegypti 60 80 100 - - - - 0 0 0 n 0 0 0

Culex 10 50 70 100 - - 0 0 0 0 0 0 Q quenquifaciatus

b. Concentration: 0.1 g in 100 ml:

Table 2:

Daia has been expressed in percent mortality

Example 8: Evaluation of the composition comprising 1% w/w mixture of Polyethylene oxide modified heptamethyl tri-siloxane and allyloxypolyethylene glycol in 100 ml. of water through WHO protocols like walk in hood chamber (for hand held spray) and Peet Grady chamber (aerosol)

Table-3: Bioefficacy of the above composition against Aedes aegypti - Data on knockdown and mortality

Temperature: 27 ± 2 °C,

Relative Humidity: 50 ± 5%

Table 4:

Aerosol Bioefficacy test against Mosquitoes in Direct Spray Project :

No. of mosquitoes : 10

Species: Aedes aegypii

Treat insect: Adults

Treatment Apparatus: CSMA Spray Tower in Walk -in hood

Target Discharge: 1 seconds

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 limitation with respect to the specific embodiments illustrated is intended or should be inferred.