NZ540392A - Parasiticide composition for controlling parasite infestation in animals - Google Patents

Abstract

A water washable parasiticide composition is disclosed which is suitable for use as a pour on composition for controlling parasite infestation on animals such as sheep or cattle, wherein the composition comprises a combination of an insect growth regulator IGR (such as triflumuron, fluazuron, cyromazine or methoprene(, a macrocyclic lactone (such as avermectin, ivermectin, abamectin, doramectin or milbemycins), a surfactant, an organic solvent and optionally a synthetic pyrethroid to provide a broad spectrum of activity against mature/immature lice and helminthes. Water washability is achieved by basing the composition on an organic solvent selected from the group consisting of glycols, glycol ethers, glycol ether acetate, C1-C8 alkyl pyrrolidones, butyrolactones, aliphatic hydrocarbons, aromatic hydrocarbons and mixtures thereof together with a surfactant.

Description

New Zealand Paient Spedficaiion for Paient Number 540392 5V0 3 92 i PARASITICIDE COMPOSITION Technical Field This invention relates to parasiticide compositions, especially liquid compositions for use in the treatment of parasite infestations in animals such as sheep 5 and/or cattle.

Background Art Parasiticide compositions are widely used in the veterinary field to control parasite infestations in/on animals, particularly farm animals. There are numerous types of parasites known to infest animals and these can be classified as ectoparasites 10 (which live on the outside of an animal's body) and endoparasites or helminths (which live inside an animal's body).

Fleas, ticks and lice are examples of ectoparasites and lice infections are especially common in farm animals such as sheep. Tape worms, flat worms and round worms are examples of helminths and helminth infections are common in farm animals. 15 A large number of compounds are known to have parasiticidal properties. Insect growth regulators (IGRs) such as chitin synthesis inhibitors and juvenile hormone mimics have been used as ectoparasiticides. Chitin synthesis inhibitors such as triflumuron act to prevent the formation of new chitin (the substance that makes up the insect's exoskeleton) by preventing the enzyme necessary to produce chitin from 20 functioning. Juvenile hormone mimics such as methoprene act to maintain ectoparasites in their immature stage thus preventing maturity and reproduction. These IGRs been used in formulations to prevent the development of immature lice, for example in the fleece of sheep. However, IGRs are ineffective against mature lice. They are also ineffective against helminths. Having regard to this shortcoming, it 25 would be desirable to provide a composition that is effective both in killing mature lice and helminths as well as preventing the development of immature lice.

Another group of compounds previously used to control parasite infections is macrocyclic lactones. These compounds are effective as both an anthelmintic (for killing helminths) and an ectoparasiticide (for killing adult mites and lice). The 30 macrocyclic lactone groups of compounds include avermectins and milbemycins and these compounds act by blocking the nerve channels of the insect.

Various physical forms of parasiticide compositions are known including liquid formulations which may be given to the animal orally (by way of a drench) or topically (by way of a "pour-on" formulation). Pour-on formulations are administered by 35 application to a localised area usually on the back of the animal. Both oral drenches and pour-on formulations are often administered using an applicator.

INTELLECTUAL PROPERTY OFFICE | OF N,Z. 3 0 MAY 2005 ii«=C£lVE.'0 One problem associated with liquid formulations of parasiticide compositions containing an IGR is that the applicator becomes clogged due to crystallisation of the IGR from the parasiticide composition. The crystallisation is due to low solubility of the IGR in water and limited solvation power of the solvent system in the composition.

Macrocyclic lactones are also of limited solubility in water. It would be desirable, therefore, to ensure that a parasiticide composition containing an IGR is not subject to this limitation in use.

The problem of applicator clogging also arises when applying formulations containing macrocyclic lactones. This is surprising owing to the low concentrations of 10 macrocyclic lactones generally used in pesticide formulations. The problems of macrocyclic lactone clogging is further exacerbated by the additional inclusion of an IGR.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a 15 context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia before the priority date of each claim of this application.

Disclosure of Invention 20 The present inventors have now found a means to provide a parasiticide composition that is effective against immature lice, mature lice and helminths, which includes an insect growth regulator (IGR) and a macrocyclic lactone and is water washable.

Accordingly, in a first aspect, the present invention is directed to a water 25 washable parasiticide composition comprising: 0.01 - 30%w/v of one or more IGR; 0.01 - 4%w/v of one or more macrocylic lactones; 0.005 - 30%w/v of one or more surfactants; the balance being an organic solvent selected from the group consisting of 30 glycols, glycol ethers, glycol ether acetate, Cj-Cg alkyl pyrrolidones, butyrolactone, aliphatic hydrocarbons, aromatic hydrocarbons and mixtures thereof.

The inventor has surprisingly found that even low concentrations of a macrocyclic lactone in a formulation can result in clogging of an applicator but that this clogging problem can be ameliorated by the inclusion of a surfactant which renders the 35 macrocyclic lactone/IGR formulation water washable. 3 The composition may additionally comprise 0.01-20%w/v of a synthetic pyrethroid.

In a second aspect, the present invention is directed to a method of controlling parasites in an animal, the method comprising administering to the animal an effective 5 amount of the parasiticide composition according to the first aspect of the invention.

In a third aspect, the present invention is directed to the use of the parasiticide composition according to the first aspect of the invention in the preparation of a medicament for the control of parasites in an animal.

In a fourth aspect, the present invention is directed to a method of cleaning a 10 device containing a residual amount of a water washable parasiticide composition according to the first aspect of the invention, the method comprising washing the device with an aqueous solution in a manner so as to effectively remove substantially all of the composition from the device.

Throughout the specification it will be understood that the term "water 15 washable" means that when water is added to the parasiticide composition, the IGR and macrocyclic lactone form a coarse emulsion which contains fine crystals of IGR and macrocyclic lactone.

The IGR is preferably a chitin synthesis inhibitor such as bistrifluron, buprofezin, chlorfluazuron, cyromazine, diflubenzuron, flucycloxuron, flufenoxuron, 20 hexaflumuron, lufenuron, novaluron, noviflumuron, penfluron, teflubenzuron or a juvenile hormone mimic such as methoprene. It may also be dicyclanil. The most preferred IGRs are triflumuron and fluazuron.

The IGR is included in the composition in the concentration of 0.01 - 30%w/v. Preferably the concentration used is in the range of 1 - 10%w/v, more preferably 1-5% 25 w/v, and most preferably about 2.5%w/v. A concentration of about 2.5%w/v of IGR in the composition provides a practical dose range for use in treating animals such as sheep. A concentration below 2.5%w/v results in the requirement of a higher dose volume and results in fewer sheep being treated per pack of parasiticide composition. A concentration higher than 2.5%w/v results in a crystallisation problem which can 30 only be overcome by using an increased amount of the surfactant.

The macrocyclic lactone may be avermectins such as abamectin, ivermectin, dormectin or eprinomectin. It may also be a milbemycin such as leptmectin, milbemectin, milbemectin oxime or moxidectin. The most preferred macrocyclic lactones are abamectin and ivermectin. 4 The macrocyclic lactone is included in the composition in the concentration of 0.01 - 4%w/v. Preferably, the concentration used is in the range of 0.05 - 3%w/v, more preferably 0.1-2 %w/v, and most preferably 0.5 - l%w/v.

One or more surfactants is included in the composition. The surfactant may be 5 selected from non-ionic, anionic, cationic or amphoteric surfactants. It has surprisingly been found that the addition of a surfactant into the parasiticide composition reduces the crystal size of the IGR and macrocyclic lactone during washing with water in such a way that the applicator device will not clog and can be reused again. The surfactant may also function as a spreading agent.

Preferably, a non-ionic surfactant is used. Non-ionic surfactants may be selected from the group consisting of C8-C10 alkylphenol ethoxylates, C9-C17 alcohol ethoxylates, C8-C20 alkyl amine ethoxylates, castor oil ethoxylates, lanolin alcohol ethoxylates, sorbitan fatty acid ester ethoxylates, sorbitan fatty acid esters and mixtures thereof.

The C8-C10 alkylphenol ethoxylates preferably contain from 2 to 100 moles of ethylene oxide and may be selected from but not limited to the commercially available products identified as Teric N9, Teric N20 and Teric N100. The C9-C17 alcohol ethoxylates preferably contain from 2 to 25 moles of ethylene oxide and may be selected from but not limited to the commercially available products identified as Teric 20 9A2 and Teric 16A16. The C8-C20 alkyl amine ethoxylates preferably contain from 5 to 20 moles of ethylene oxide and may be selected from but not limited to the commercially available products identified as Teric 13M15 and Teric 18M20. The castor oil ethoxylates preferably contain from 5 to 60 moles of ethylene oxide and may be selected from but not limited to the commercially available products identified as 25 Cremophor EL, Acconon CA-5 and Teric 380. The lanolin alcohol ethoxylates preferably contain from 5 to 40 moles of ethylene oxide and may be selected form but not limited to the commercially available products identified as Polycol 5 and Polycol 40. The sorbitan fatty acid ester ethoxylates preferably contain 4 to 20 moles of ethylene oxide and may be selected from but not limited to Polysorbate 20, Polysorbate 30 60 and Polysorbate 80. The sorbitan fatty acid esters preferably have a chain length of C18-C60 and more preferably have an HLB of 2-9 and may be selected from but not limited to sorbitan monoisostearate, sorbitan monostearate, Hodag SML and Span 25.

The surfactant is in a concentration of 0.005 - 30%w/v. Preferably, the concentration used is in the range of 0.01 - 20%w/v most preferably 0.1 - 15%w/v. 35 The availability of surfactants is shown in Table 1.

Table 1 - Surfactant Availability A\aiLthlc tiom Triflumuron Jurox Dipropyleneglycol monomethyl ether ICI N-methyl pyrrolidone APS Teric N9, Teric N20, Teric N100, Teric 9A2, Teric 16A16, Teric 13M15, Teric 18M20 and Teric 380 ICI Cremophor EL BASF Corporation Acconon CA-5 Karlshamns USA Inc Polycol 5 and Polycol 40 CRODA Polysorbate 20 (trade name Tween 20), Polysorbate 60 (trade name Tween 60) and Polysorbate 80 (trade name Tween 80) ICI Hodag SML Calgene Span 25.

ICI A variety of pyrethroids, particularly synthetic pyrethroids may be optionally 5 included in the composition. These include the following: alpha cypermethrin, deltamethrin, cypermethrin, lambda cyhalothrin, permethrin and flumethrin. Typically, these pyrethroids will be used in a concentration of 0.01 - 20%w/v, preferably 0.1 -10%w/v, most preferably 0.5 - 5%w/v. Especially preferred is a concentration of about 1.2%w/v.

An organic solvent selected from the group consisting of glycols, glycol ethers, glycol ether acetate, Ci-Cs alkyl pyrrolidones, butyrolactone, aliphatic hydrocarbons, aromatic hydrocarbons and mixtures thereof is included in the composition of the invention. The organic solvent forms the balance of the composition. The concentration of the solvent may be in the range of 36-99.975% w/v. The preferred 15 aliphatic hydrocarbons are those with a boiling point between 30 and 320 °C such as hexane, heptane and pentane. The preferred aromatic hydrocarbons are those with a boiling point between 100 and 240 °C such as toluene, xylene and alkylnapthalenes (e.g. Solvesso 200™). A preferred solvent mixture is dipropyleneglycol monoethyl ether and N-methyl pyrrolidone, optionally with Solvesso 200™ or hexane. 6 The composition may further include additives which are commonly used in parasiticide compositions including but not limited to dyes, perfumes, preservatives, antioxidants and viscosity modifiers.

To produce the compositions of the invention, the IGR, macrocyclic lactone and 5 optionally the synthetic pyrethroid are dissolved in the organic solvent. The surfactant is added and the solution mixed until homogenous.

The composition according to the present invention may be used as a pour-on preparation or as a drench. Preferably, the composition is used as a pour-on preparation. The composition is preferably applied along the back of the animal using 10 an applicator device, such as a gun. After use, precipitated crystals of the IGR and macrocyclic lactone can be removed from the applicator by washing with an aqueous solution or water.

Whilst compositions made according to the invention will find the greatest application in sheep and cattle, they are also useful in treating parasite infestations in 15 deer, buffalo and goats.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Modes for Carrying out the Invention In order to better understand the nature of this invention, a number of examples will now be described.

Example 1 \mount < tr 1 ) Triflumuron Avermectin Polysorbate 80 2 N-methylpyrrolidone 500 Dipropyleneglycol monoethyl ether to 1 L Example 2 Amount (g L) Fluazuron Avermectin Teric N9 N -methylpyrr olidone 500 Dipropyleneglycol monoethyl ether 300 Solvesso 200™ to 1L Example 3 Ingredient Triflumuron Ivermectin Polysorbate 80 4 N-methylpyrrolidone 600 Dipropyleneglycol monoethyl ether 100 Hexane to 1L Example 4 Triflumuron Ivermectin Alphacypermethrin Polysorbate 80 4 N-methylpyrrolidone 600 Dipropyleneglycol monoethyl ether 100 Hexane to 1L

Claims (5)

8 In Examples 1-3, each composition was prepared by dissolving the IGR and the avermectin in the organic solvents followed by the addition of the surfactant Teric N9 or Polysorbate 80. In Example 4, the composition was prepared by dissolving the IGR, 5 ivermectin and alphacypermethrin in the organic solvents followed by the addition of the Polysorbate 80. It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly 10 described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. 9 CLAIMS:

1. A water washable parasiticide composition comprising: 0.01 - 30%w/v of one or more IGR; 0.01 - 4%w/v of one or more macrocyclic lactones; 5 0.005 - 30%w/v of one or more surfactants; and the balance being an organic solvent selected from the group consisting of glycols, glycol ethers, glycol ether acetate, Ci-Cg alkyl pyrrolidones, butyrolactone, aliphatic hydrocarbons, aromatic hydrocarbons and mixtures thereof.

2. The water washable parasiticide composition according to claim 1 further 10 comprising 0.1 - 20%w/v of one or more synthetic pyrethroids.

3. The water washable parasiticide composition according to claim 1 or 2 wherein the organic solvent comprises N-methyl pyrrolidone and dipropyleneglycol monoethyl ether.

4. The water washable parasiticide composition according to any one of the 15 preceding claims wherein the IGR is selected from triflumuron, fluazuron, cyromazine or methoprene and the macrocyclic lactone is selected from avermectin, ivermectin, abamectin, doramectin and milbemycins.

5. A water washable parasiticide composition comprising: 1 - 5%w/v of one or more IGR selected from the group consisting of 20 triflumuron, fluazuron, cyromazine or methoprene; 0.1 - 2%w/v of one or more macrocyclic lactones selected from the group consisting of avermectin, ivermectin, abamectin, doramectin and milbemycins 0.1 - 15%w/v of one or more of surfactants selected from the group consisting of castor oil ethoxylates, lanolin alcohol ethoxylates, sorbitan fatty acid ester ethoxylates 25 containing from 4 to 20 moles of ethylene oxide and C8-C10 alkylphenol ethoxylates containing from 2 to 100 moles of ethylene oxide; and optionally 0.5 - 5%w/v of a synthetic pyrethroid selected from the group consisting of alpha cypermethrin, deltamethrin, cypermethrin, lambda cyhalothrin, permethrin and flumethrin; 30 the balance being an organic solvent mixture comprising N-methyl pyrrolidone . and dipropyleneglycol monoethyl ether.