Method for Applying a Powder Insect Repellent Composition

Abstract

Disclosed is a method for repelling insects from the skin of a subject that reduces the absorption of insect repellent into the skin. The method includes the step of topically applying a powder insect repellent composition to the skin of the subject. The powder insect repellent composition may include solid particles of talc, calcium silicate, and/or cyclodextrin. The powder insect repellent composition may include natural oils, DEET, and/or paricidin as active ingredients. The powder insect repellent composition may also include antihistamine and/or a colorant.

Claims

1. A method for repelling insects from the skin of a subject comprising the step of topically applying a powder insect repellent composition to the skin of the subject.

2. The method of claim 1 wherein the powder insect repellent composition comprises at least one of the following: talc, calcium silicate, and cyclodextrin.

3. The method of claim 2 wherein the powder insect repellent composition comprises talc present in a concentration of from about 0.01% to about 95% w/w.

4. The method of claim 2 wherein the powder insect repellent composition comprises calcium silicate present in a concentration of from about 0.01% to about 40% w/w.

5. The method of claim 2 wherein the powder insect repellent composition comprises cyclodextrin in a concentration of from about 0.01% to about 40% w/w.

6. The method of claim 2 wherein the powder insect repellent composition comprises at least two of: talc, calcium silicate, and cyclodextrin.

7. The method of claim 2 wherein the powder insect repellent composition comprises talc, calcium silicate, and cyclodextrin.

8. The method of claim 1 wherein the powder insect repellent composition comprises an insect repellent that is a natural oil.

9. The method of claim 1 wherein the powder insect repellent composition comprises a plurality of different insect repellents, each insect repellent being a natural oil.

10. The method of claim 1 wherein the powder insect repellent composition comprises DEET.

11. The method of claim 1 wherein the powder insect repellent composition comprises picaridin.

12. The method of claim 1 wherein the powder insect repellent composition comprises solid powder particles coated with at least one liquid insect repellent.

13. The method of claim 12 wherein each at least one liquid insect repellent comprises a natural oil.

14. The method of claim 13 wherein each natural oil comprises at least one of the following: mustard, eucalyptis, pine, peppermint, menthol, camphor, garlic, wintergreen, rose geranium, litsea cubeba, lemongrass, pulegone, oleoresin capsicum, neem, citronella, and catnip.

15. The method of claim 12 wherein the solid powder particles are particles of at least one of the following: talc, calcium silicate, and cyclodextrin.

16. The method of claim 1 wherein the powder insect repellent composition comprises solid powder particles coated with at least one of the following: DEET and picaridin.

17. The method of claim 16 wherein the solid powder particles are particles of at least one of the following: talc, calcium silicate, and cyclodextrin.

18. The method of claim 17 wherein the solid powder particles comprise from about 0.01% to about 40# w/w of the powder insect repellent composition and the solid powder particles comprise at least one of the following: talc, calcium silicate, and cyclodextrin.

19. The method of claim 1 wherein the powder insect repellent composition comprises an antihistamine.

20. The method of claim 1 wherein the powder insect repellent composition comprises at least one of the following: a fragrance and a colorant.

Description

DETAILED DESCRIPTION

Definition of Terms Used

[0043] Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art.

[0044] As used herein and in the claims, the singular forms a, an, and the include plural reference unless the context clearly dictates otherwise. For example, reference to an excipient is a reference to one or more excipients and equivalents thereof known to those skilled in the art.

[0045] The term about is used to indicate that a value includes the standard level of error for the substance or method being employed to determine the value. The terms comprise, have and include are open-ended linking verbs. Any forms or tenses of one or more of these verbs, such as comprises, comprising, has, having, includes and including, are also open-ended.

[0046] The terms treat, treated, treatment, or treating used herein refers to a preventative measure to repel insects.

[0047] Combination Therapy is defined as the treatment wherein two or more active ingredients are co-administered to achieve special advantages over their individual therapeutic effects. They may produce a synergistic effect where the total therapeutic effect is greater than the sum of their therapeutic effects. Combination therapy may allow the use of lower doses of one or all the active ingredients used in the formulation.

[0048] An Active Agent is defined as the chemical substance, which shows a useful clinical effect when administered in appropriate doses and as a suitable dosage form. In this case, the clinical effect is to repel insects such as mosquitoes or flies.

[0049] An Active Effective Amount is defined as the amount of an active agent, which is effective for producing some desirable effect with a reasonable benefit/risk ratio applicable to a treatment.

[0050] A Dosage Form or A Delivery System is defined as a product developed to deliver actives to a desired site where the insect repellency action is needed. A desired site is an area where the insect repellency action is desired. These are insect products marketed for use, which contain one or more active ingredients and excipients. These are delivered onto human body by various methods and routes of administration. The route of application is topical administration. In this patent application, the desired site can be any other surface such as bed sheet, sleeping bag etc.

[0051] Formulation Composition of a dosage form lists all the ingredients in the formulation and their quantities. It does not describe the process of manufacturing the formulation.

[0052] An Effective Composition of a dosage form lists all the ingredients and their quantities, which provides a desired effect. The dosage form contains effective amounts of active ingredients.

[0053] Excipients are compounds used in the dosage form along with the active ingredient. The actives are expected to be stable in the dosage form along with the excipients throughout the shelf-life of the dosage form.

[0054] Toxicologically Acceptable Materials refers to those compounds or materials, which are suitable for use in contact with tissue or organs of humans and animals without excessive toxicity, irritation, allergic response or any other problems. Only toxicologically acceptable excipients are used in the formulations in this patent application.

[0055] Chemical stability with respect to the active agent means that an acceptable percentage of degradation products are produced by chemical pathways such as hydrolysis, thermal degradation or oxidation.

[0056] Physical stability with respect to the therapeutic agent means that an acceptable percentage of aggregates, loss of smell or generation of foul smell, loss of original color or discoloration, crystals, visible mold/fungus is formed.

[0057] The formulation is considered stable when it shows good chemical and physical stability.

[0058] The term synthetic insect repellent is considered when active substances or products are prepared by chemical synthesis in a laboratory or in a chemical manufacturing plant.

[0059] The term natural insect repellent is considered when the active substances exist in or formed by nature. The natural source, such as flowers, leaves, is directly used in the formulation or the actives are extracted using solvent and then the extract is used in the formulation

[0060] The term insect describes as an animal that have three pairs of legs, a segmented body divided into three regions (head, thorax, and abdomen), one pair of antennae and, usually, wings. Few insects such as ants, spiders have 8 legs.

[0061] The term anti-histaminic component describes as a drug or other compound that inhibits the physiological effects of histamine, used especially in the treatment of allergies.

[0062] The term anti-inflammatory component describes as a substance or compound that reduces inflammation or swelling.

[0063] A fragrance is defined as a compound which imparts sweet or pleasant scent. Fragrances can be either natural or synthetic. Active components of many of the natural fragrances have been identified and synthesized. Derivatives of natural chemicals have been prepared and are being used as synthetic fragrances. One uses combination of fragrances to produce a desired effect. The role of fragrances in this formulation is to mask the smell of various actives added and make the insect repellent pleasant.

[0064] Insect repellents are commonly used personal protection to avoid insect bites. As the word suggests, an Insect repellent formulation is the one when applied on the body or on the surrounding areas, the insects are repelled and insect do not land. If they happened to land, they are repelled from biting the subject. A Powder insect repellent formulation is the one which is a powder form. The powder applied over the surface where we desire an insect repellency action. As mentioned in the background information, mosquitoes can spread many serious diseases and the current formulations, in particular, can be used as mosquito repellents. Over the years, many mosquito repellent formulations such as cream, spray, coil, mat, incense and any more have been prepared. Some of the marketed products of mosquito repellent have been listed in Table 1. These formulations have several advantages and disadvantages based on the type of dosage form. Formulations like cream and spray are sometimes sticky to the skin and chances of absorption of mosquito repellent agent or other excipients present in the formulation is more. These formulations soften the skin and open the pores of skin. The actives from the formulations can be absorbed in the body. Formulations like coils and incense produce fumes, which may irritate eyes and lungs. Sometime, it is difficult to inhale or on ingestion of fumes can lead some serious allergic conditions. Also, synthetic agents used as mosquito repellent have serious health issues like eye and skin irritation, insomnia, mood disturbances, seizure, etc.

[0065] Cyclodextrin: Cyclodextrins (CD) are a family of compounds made up of sugar molecules bound together in a ring (cyclic oligosaccharides). Exposure of starch to an enzyme called cyclomaltodextrin glucanotransferase, naturally excreted by B. macerans, yields a mixture of six-, seven- and eight-member rings corresponding to -CD, -CD and -CD, respectively. For the purpose of this patent application, the cyclodextrin can be one or more the following-cyclodextrin (6 membered sugar ring molecule), -cyclodextrin (7-membered sugar ring molecule), -cyclodextrin (8-membered sugar ring molecule), hydroxypropyl betacyclodextrin, sulfobutylether betacyclodextrin, and randomly methylated beta cyclodextrin.

[0066] Calcium Silicate: Calcium silicate is the chemical compound Ca.sub.2SiO.sub.4, also known as calcium orthosilicate and sometimes formulated 2CaO.SiO.sub.2. It is one of a group of compounds obtained by reacting calcium oxide and silica in various ratios, e.g. 3CaO.SiO.sub.2, Ca.sub.3SiO.sub.5; 2CaO.SiO.sub.2, Ca.sub.2SiO.sub.4; 3CaO.2SiO.sub.2, Ca.sub.3Si2O.sub.7 and CaO.SiO.sub.2, CaSiO.sub.3. Calcium silicate is a white free-flowing powder derived from limestone and diatomaceous earth.

[0067] Talc: Talc is a naturally occurring mineral, mined from the earth, composed of magnesium, silicon, oxygen, and hydrogen and having chemical composition of Mg.sub.3Si.sub.4O.sub.10 (OH).sub.2 or H.sub.2Mg.sub.3 (SiO.sub.3).sub.4. It has been used as filler, lubricant and glidant in the pharmaceutical formulations as well as in cosmetic formulations as abrasive, absorbent, anticaking agent, opacifying agent and skin protectant due to its high functionality. Following are the types of talc powder. [0068] 1. Talc Lump (SiO.sub.2: 52%, MgO: 30%, whiteness: 80%). [0069] 2. Chemical grade talcum powder (SiO.sub.2: 60% 1250-mesh or SiO.sub.2: 60% 800-mesh). [0070] 3. Ceramic grade talcum powder (SiO.sub.2: 50-55% 325-mesh, SiO.sub.2: 55-60% 325-mesh, Talc Powder SiO.sub.2: 60% 400-mesh). [0071] 4. Cosmetic grade talc powder (Whiteness: 90%-95%, SiO.sub.2: 60%, MgO: 30%). [0072] 5. Pharmaceutical grade talcum powder (Whiteness: 90%, SiO.sub.2: 60% 325-mesh) Food grade talcum powder (SiO.sub.2: 60% 325-mesh). [0073] 7. Paper grade talcum powder (whiteness: 86% min-95% min, SiO.sub.2: 35% min-60% min, MgO: 30% min).

[0074] Pine oilPine oil is a colorless to pale yellow essential oil. Depending on its source, pine oil may either have a fresh, earthy, and forest-like fragrance or a strong, dry, balsamic, turpentine-like odor. Pine oil can be obtained from various pine species such as Pinus sylvestris, Pinus pinaster, Pinus maritima, Pinus radiate, Pinus koraiensis, Pinus pumila, Pimus luchuensis, Pinus palustris, Pinus bungeana, Pinus thunbergii, Pinus densiflora, Pinus parviflora, Pinus pentaphylla, Pinus koraiensis, Pinus pumila, Pimus luchuensis, Pinus palustris or Pinus bungeana or a mixture of these. Pine oil is extracted through steam distillation of the needles, twigs and cones of the pine tree.

[0075] Mustard oilThe term mustard oil is used for two different oils that are made from mustard seeds: a fatty vegetable oil resulting from pressing the seeds, and an essential oil resulting from grinding the seeds, mixing them with water, and extracting the resulting volatile oil by distillation. Mustard oil has a typical pungent and sharp flavor. Mustard oil also has an antibacterial, antifungal, and anti-inflammatory action.

[0076] Eucalyptus oilEucalyptus oil is the generic name for distilled oil from the leaf of Eucalyptus tree. The leaves of selected eucalyptus are steam distilled to extract eucalyptus oil. Cineole-based eucalyptus oil is used as an insect repellent and biopesticide.

[0077] Neem oilNeem oil is a vegetable oil pressed from the fruits and seeds of the neem (Azadirachta indica). For decades, neem oil has been used as an insect repellent.

[0078] Citronella oilCitronella oil is one of the essential oils obtained from the leaves and stems of different species of Cymbopogon (lemongrass). Citronella oil is also a plant-based insect repellent and has been registered for this use in the United States since 1948.

[0079] Lemongrass oilLemongrass is also known by Cymbopogon and it is a genus of about 55 species of grasses. Cymbopogon essential oils and constituents present therein e.g. citral, geraniol, citronellol, citronellal and piperitone, have been known to possess impressive antibacterial, antifungal, antiyeast, insecticidal and insect repellent activities for a long time.

[0080] Geranium oilGeranium oil obtained from species of Pelargonium graveolens. Geranium oil, taken from the flower of the same name, is part of a family of natural and effective insect repellents that include lemongrass and citronella oils.

[0081] PrallethrinPrallethrin is a pyrethroid insecticide. Prallethrin 1.6% w/w liquid vaporizer is a repellent insecticide, which is generally used for the control of mosquitoes in the household. The World Health Organization published in 2004 that Prallethrin is of low mammalian toxicity, with no evidence of carcinogenicity and is very toxic to bees and fish but of low toxicity to birds.

[0082] DEETDEET (chemical name N,N-diethyl-meta-toluamide) is used as the active ingredient in many insect repellents. Insect repellents that contain DEET offer the best protection against mosquito bites. DEET is designed for direct application to skin to repel insects, rather than kill them. Despite severe toxic properties, which can dramatically affect adults and children including allergic reaction, dermatitis, neurological and cardiovascular toxicity, the risk of toxic effects from DEET is considered slight. Nevertheless, DEET should always be used lowest effective dose possible.

[0083] PicaridinPicaridin, also known as Icaridin (hydroxyethyl isobutyl piperidine carboxylate), is a compound found in many mosquito repellents used in Europe, Australia, Latin America, and Asia. Its chemical name is KBR 3023. Years of safe use of picaridin in other parts of the world attest to its safety and effectiveness.

[0084] The inventors attempted to overcome some of disadvantages of currently commercialized insect repellents by developing a novel topical powder formulation containing natural (essential oils) oils and synthetic compounds as mosquito repellent. Natural oils have been used in mosquito repellency for more than a century in much of the world and are the most widely used natural repellents today. Mosquito repellency is believed to be due to the synergistic interaction of the chemical components present in natural oil. Another key aspect of this disclosure is the use of cyclodextrin and calcium silicate. Calcium silicate is known for its CO.sub.2 (carbon dioxide) absorbing properties. Female mosquitoes have olfactory (odor-sensing) organs called palps. These instruments are attuned to the odor of CO.sub.2, which we produce every time we exhale. High concentrations of CO.sub.2, which mosquitoes can detect from more than 150 feet away, offer an initial temptation to hungry mosquitoes. Hence calcium silicate is used here may act as a mosquito repellent by reducing the level of CO.sub.2. [Source: US department of health and human service]. Also, the loading of oils in to powder is difficult. So, calcium silicate and cyclodextrin play an important role in loading oils in the powder formulation.

[0085] Microorganisms reside on human skin, mainly in the superficial layers of epidermis and upper parts of hair follicles. They are referred as skin microbiota. Skin flora is usually non-pathogenic, and either commensal (are not harmful to their host) or mutualistic (offer a benefit). Each person has different set of microorganisms. The benefits these microorganisms can offer include preventing transient pathogenic organisms from colonizing the skin surface, either by competing for nutrients, secreting chemicals against them, or stimulating the skin's immune system. These microorganisms produce and secrete their own chemicals or convert chemicals on our skin to other airborne chemicals. Mosquitoes can smell these chemicals and get attracted. That is the reason, some people get bitten by mosquitoes more than others. The formulations in this patent application has cyclodextrin. Cyclodextrins are bucket-shaped molecules in which chemical can get trapped due to complexation. When we sweat, the cyclodextrin in the formulation would dissolve in the sweat. Once in the dissolved state, cyclodextrin would absorb chemicals produced by microorganisms and the chemicals will not be air-borne. Once devoid of these chemical smell, the person will not attract mosquitoes. Thus, calcium silicate and cyclodextrin may be playing a role as an active apart from helping to load the oily actives in the powder formulation.

TABLE-US-00001 TABLE 1 Currently Marketed mosquito repellent formulations in the US. Type of formulation Active Ingredient Spray 23.8% DEET Lotion 20% DEET Spray 6.65% DEET Spray Oil of lemon eucalyptus; p-menthane 3,8-diol (PMD) Spray 2% Soybean Oil Spray 4.75% DEET Lotion, Towelettes, Spray 7.5% IR3535 Spray 10% Citronella Spray 12% Citronella; 2.5% peppermint oil; 2% cedar oil; 1% lemongrass oil; 0.05% geranium oil Spray 10% Citronella; 2% peppermint oil Towelettes, Spray 5% Citronella Lotion, Spray 0.1% Citronella Liquid solution Active Ingredient not known Lotion 0.05% Citronella Vapor based wristband 9.5% DEET Vapor based wristband 9.5% DEET Vapor based wristband 25% Citronella Vapor based liquid Prallethrin 1.6% w/w Vapor based liquid, Prallethrin 1.6% w/w coil, mat, paper Cream DEET Spray Spray, candle, vapor Citronella oil, eucalyptus liquid, coil oil, DEET Patch (clothing) Citronella oil

[0086] Creams, ointments and solutions generally contain many penetration enhancers. They increase percutaneous absorption of actives by increasing the thermodynamic activity of the penetrant, thereby increasing the effective escaping tendency and concentration gradient of the diffusing species (Remington, 20.sup.th Edition, Chapter 44, page 842). Some of the penetration enhancers are solvents, surfactants, and miscellaneous chemicals. Some of these increase the degree of hydration of stratum corneum or disrupts its lipoprotein matrix. Chemicals like water, ethanol, fatty acids, surfactants etc. increase permeation of active molecules, such as mosquito repellents in this case. The skin permeation in older people may be more compared to young people due to lesser diffusional resistance by stratum corneum. Consumption of alcohol makes the peripheral blood vessels relax to allow more blood to flow through the skin and tissues. The actives in the mosquito repellents diffused through the skin are taken away in the body increasing absorption of more actives from the mosquito repellents.

[0087] In other embodiment, natural oil or combination of oils are used. Commonly used oils areeucalyptus, mustard, pine, peppermint, menthol, camphor, garlic, wintergreen (methyl salicylate), rose geranium, litsea cubeba, lemongrass, oil of penny royal (pulegone), oleoresin capsicum, catnip etc.

[0088] In an another embodiment, diphenhydramine hydrochloride is used as anti-histamine agent to avoid allergic reaction. Suitable salt of other antihistamines used in the formulation are selected from one or more of, but not limited to: triprolidine, pyrilamine, chlorcyclizine, carbinoxamine, tripelennamine, brompheniramine, terfenadine, and chlorpheniramine, and the like. Other antihistamines are represented by, but are not limited tosuitable salts of chlorcyclizine, clemastine fumarate, pyrilamine maleate, cetirizine hydrochloride, astemizole, loratadine, dexchlorpheniramine, fexofenadine, levocetrizine, promethazine, desloratadine, hydroxyzine, pheniramine, dipheniramine, acrivastine azelastine, ebastine, mizolastine and the like.

[0089] In another embodiment, synthetic mosquito repellent agent N, N-diethyl-3-methyl-benzamide, also called DEET is used. Other examples of synthetic mosquito repellent arepicaridin (butan-2-yl 2-(2-hydroxyethyl)piperidine-1-carboxylate), N, N-diethyl-benzamide, IR3535 (3-[N-butyl-N-acetyl]-aminopropionic acid, ethyl ester), dimethyl phthalate, metofluthrin, permethrin, diethyl carbate, ethyl hexanediol and like.

[0090] In another embodiment of the inevention, hydrocortisone is used as an anti-inflammatory agent. Other anti-inflammatory actives are selected from one or more of but not limited to: beclomethasone dipropionate, betamethasone, budesonide, dexamethasone, methylprednisolone, prednisolone, prednisone and triamcinolone.

[0091] Following are the key advantages of the disclosed composition: [0092] 1. The formulation is safe, eco-friendly, [0093] 2. It easy to use and it maximizes the repellency power against mosquito. [0094] 3. The product is cheap and it uses many natural active ingredients. [0095] 4. Topical powder formulation for mosquito repellent can be used in other place such as houses, restaurants, parks. One can spray the powder on the bed sheet and need not apply on the body.

[0096] With the following examples, one skilled in the art, can understand and use the disclosed composition.

Example 1

[0097] Table 2 lists the composition of the topical mosquito repellent powder Formulation #1.

TABLE-US-00002 TABLE 2 Composition of the topical mosquito repellent powder Formulation # 1. Ingredients Quantity % Mustard oil 2 Eucalyptus oil 3 Ethanol 6 Calcium silicate 24 Fragrances 0.5 Talc 64.5

[0098] Weigh accurate quantity of mustard oil, eucalyptus oil and mix well. Dissolve the mixture of oils in ethanol. Mix this ethanolic solution with calcium silicate.

[0099] Mix well the mixture of oils with calcium silicate and talc. Air dry and then pass through a fine mesh sieve.

Example 2

[0100] In the Formulation #2, diphenhydramine HCl is added to take care of allergic reactions (Table 3).

TABLE-US-00003 TABLE 3 Composition of the topical mosquito repellent powder Formulation # 2. Ingredients Quantity % Mustard oil 2 Citronella oil 1.5 Neem oil 1.5 Ethanol 6 Calcium silicate 19 Diphenhydramine HCl 1 Hydroxypropyl -cyclodextrin 6 Fragrances 0.7 Talc 62.3

[0101] Part-1 Weigh accurate quantity of mustard oil, citronella oil, neem oil and mix well. Dissolve the mixture of oils in ethanol. Mix this solution with calcium silicate.

[0102] Part-2 Mix Talc, diphenydramine and Hydroxypropyl -cyclodextrin.

[0103] Finally mix both parts 1 and 2 very well. Air dry to evaporate alcohol and pass through a fine mesh sieve.

Example 3

[0104] Formulation #3 (formulation containing DEET) has been listed in Table 4.

TABLE-US-00004 TABLE 4 Composition of the topical mosquito repellent powder Formulation # 3. Ingredients Quantity % Mustard oil 0.87 Pine oil 1.12 Neem oil 1.26 Ethanol 6.06 Eucalyptus oil 1.26 Calcium silicate 18.94 DEET 0.89 Sulfabutylether -cyclodextrin 6.06 Fragrances 0.4 Talc 63.2

[0105] Part-1 Weigh accurate quantity of mustard oil, pine oil, neem oil, DEET and mix well. Dissolve the mixture of oils and DEET in ethanol. Mix this solution with calcium silicate.

[0106] Part-2 Mix Talc and Hydroxylpropyl -cyclodextrin.

[0107] Finally mix both parts 1 and 2 very well, air dry the product and pass through fine mesh sieve.

Example 4

[0108] Composition of Formulation #4 (formulation containing DEET and picaridine combination) has been listed in Table 5.

TABLE-US-00005 TABLE 5 Composition of the topical mosquito repellent powder Formulation # 4. Ingredients Quantity % Mustard oil 1.5 Pine oil 1.5 Geranium oil 1 Ethanol 6 Calcium silicate 16 Picardin 2 DEET 3 -cyclodextrin 6 Fragrances 0.5 Talc 62.5

[0109] Part-1 Weigh accurate quantity of mustard oil, pine oil, geranium oil, DEET, picaridine and mix well. Load the mixture of oils, DEET and Picaridin in ethanol. Mix this solution with calcium silicate.

[0110] Part-2 Mix Talc and -cyclodextrin.

[0111] Finally mix both parts 1 and 2 very well, air dry and pass through fine mesh sieve.

Example 5

[0112] Table 6 lists the composition of Formulation #5 (formulation containing combination of oils and diphendramine).

TABLE-US-00006 TABLE 6 Composition of the topical mosquito repellent powder Formulation # 5. Ingredients Quantity % Mustard oil 2.5 Pine oil 1.5 Neem oil 1.5 Ethanol 6 Diphenhydramine HCl 1.5 Calcium silicate 16 DEET 4 -cyclodextrin 7 Talc 60

[0113] The manufacturing process is similar to described in previous examples.

Example 6

[0114] Table 7 lists the composition of Formulation #6 (formulation containing combination of diphenhydramine and hydrocortisone).

TABLE-US-00007 TABLE 7 Composition of the topical mosquito repellent powder Formulation # 6. Ingredients Quantity % Mustard oil 2 Pine oil 1 Neem oil 1 Eucalyptus oil 1 Citronella oil 1 Ethanol 6 Diphenhydramine HCl 1.5 Calcium silicate 15 Picaridin 2 DEET 2 Hydrocortisone 1 -cyclodextrin 6.5 Talc 60

Example 7

[0115] Table 8 lists the composition of Formulation #7

TABLE-US-00008 TABLE 8 Composition of the topical mosquito repellent powder Formulation # 7. Ingredients Quantity % Calcium silicate 25 fragrances 1 Talc 74

Example 8

[0116] Table 9 lists the composition of Formulation #8

TABLE-US-00009 TABLE 9 Composition of the topical mosquito repellent powder Formulation # 8. Ingredients Quantity % Sulfabutylether betacyclodextrin 10 Fragrances 1 Talc 89

[0117] The manufacturing procedure for Formulation #6 is same as mentioned in other examples earlier.

[0118] In all the examples, even though ethanol is listed in the initial composition, it evaporates during the air drying step. Thus, the final composition does not contain ethanol or if present, it is in small quantity.

[0119] A product from this patent application was tested in an entomology lab. In the Hand-in-Cage experiment, the forearm of a volunteer was exposed to hungry female mosquitoes placed in a cage. In a control experiment, no mosquito repellent was applied on the forearm. As soon as the forearm was placed in the cage through the glove-hole, mosquitoes landed on the forearm and started to bite. To test active products, a male and a female volunteer applied the powder mosquito repellent formulation on their forearms. They placed the forearms in the cage with hungry female mosquitoes. For both volunteers, hungry female mosquitoes did not even land on their forearm and there was no question of biting.

[0120] Formulations #3, #6 and #8 were applied on the arms and legs of other set of volunteers. They went out for a walk in an outdoor area where there were mosquitoes. All formulations repelled mosquitoes and the volunteers were not bitten by mosquitoes.

[0121] These formulations can be applied to on the bed sheets, pillow, and on night dress. If people are using a sleeping bag outdoors, they can apply the powder mosquito repellent formulation on the sleeping bag or on the tent too.

[0122] The mosquito repellent powder is easy to clean. The exposed objects or skin can be cleaned by soap and warm water.

[0123] Overall, this patent application claims a method for repelling insects from the skin of a subject comprising the step of topically applying a powder insect repellent composition to the skin of the subject. While specific examples have been presented here, various modifications can be made and the disclosure is not limited to the examples shown in this patent application. Overall, the formulations presented in the patent applications would be safer than currently available mosquito repellent formulations based on two aspects1. Selection and lesser percent of actives and the selection of powder as a delivery system. Lesser percent of actives are absorbed through the skin when applied as in a powder form due to reduced surface contact and lesser increase in the permeation of actives from the powder. The actives are either adsorbed on the surface of powder particles or absorbed in the powder particles. There are hundreds of types of mosquitoes and the compositions in this patent application have potential to be effective against all the species of mosquitoes observed in the world. The formulation was observed to be very effective when tested in the entomology lab and tested in the field with mosquitoes. The formulation described in the present patent application is effective against mosquitoes but can also be used to repel commonly observed house-flies, fruit-flies, chiggers, fleas and ticks. The compositions contain fragrances to make the formulations pleasing to smell. They also can contain some colorants such as light pink color to make them attractive.