AU773119B2 - Methods for eliminating parasites and in particular ectoparasites of vertebrates, particularly of mammals and compositions for implementing these methods - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 DIVISIONAL APPLICATION NAME OF APPLICANT: Merial ADDRESS FOR SERVICE: Melbeurne, 3000.

r: g. RZA-c 4O r or c r r ro r r INVENTION TITLE: "Methods for eliminating parasites and in particular ectoparasites of vertebrates, particularly of mammals and compositions for implementing these methods" The following statement is a full description of this invention, including the best method of performing it known to us: -_1A

-AA-

This application is a divisional of Australian Patent Application No. 36247/97, the entire contents of which are incorporated herein by reference.

The present invention relates to methods for removing parasites of vertebrates and in particular ectoparasites. Depending on the host-parasite pairs, a method according to the invention can take on a therapeutic aspect, when it is intended to prevent or treat parasitoses which are pathogenic in their nature or their induced effects, or a method may be without any therapeutic purpose, when the treatment consists in combatting parasites which cause non-pathological effects in their hosts, such as signs of discomfort or an unsightly appearance.

The invention also relates to compositions which make possible the implementation of these methods.

Parasite, within the meaning of the present invention, is understood to mean not only true parasites but also insects or other vermin capable of soiling occasional or permanent hosts or of otherwise harming them. The parasites targeted by the invention are mainly composed of arthropods and in particular insects and Arachnida, including Acarina.

More specifically, the invention relates in particular to the removal of fleas, in particular Ctenocephalides spp., in particular felis, ticks, in 25 particular Rhipicephalus spp., in particular sanguineus, and Boophilus spp., in particular microplus, myiasis-causing parasites or mange, in S particular Sarcoptes spp., in particular cabiei, and lice, in particular Damalinia spp. and Linognathus 30 spp., in companion animals (in particular dogs and cats), cattle, goats and sheep, and Suidae.

It is already known to protect vertebrates against various parasites, and in particular S* arthropods, with l-phenyl-3-cyanopyrazole derivatives, as described in Patent Applications WO 87/03781, 93/06089 and 94/21606 and European Patent Application EP-A-0,295,117. A number of methods which make possible an external application of compositions containing such compounds have been listed in these applications, in P:\OPERUgcl51880-01 clims.doc-15/09/03 -2order to combat ectoparasites. These applications also generally list methods for oral or parenteral administration, without indicating the specific host/parasite pairs which would call for them.

The present invention proposes to provide new methods for combatting parasites which makes it possible to remove many ectoparasites of vertebrates, in particular of mammals.

A particularly noteworthy object of the invention is to provide methods which, by a single administration, make it possible to remove ectoparasites with an extremely high effectiveness for a long period of time.

The subject of the invention is the use of a compound of formula (I) R2 R1

N

R 11

R

1 3 15 in which:

R

1 is a halogen atom, CN or methyl;

R

2 is S(O)nR 3 or haloalkyl;

R

3 is alkyl or haloalkyl;

R

4 represents a hydrogen or halogen atom; or an NR 5

R

6 S(O)mR 7

C(O)R

7 or C(O)OR 7 alkyl, haloalkyl or ORB radical or an N=C(R 9 (Rio) radical;

R

5 and R 6 independently represent a hydrogen atom or an alkyl, haloalkyl, alkoxycarbonyl, C(O)alkyl or S(O)rCF 3 radical; or R 5 and Rg can together form a divalent alkylene oO* *oooo *oeo O 0 3 radical which can be interrupted by one or two divalent heteroatoms;

R

7 represents an alkyl or haloalkyl radical;

R

8 represents an alkyl or haloalkyl radical or a hydrogen atom; R9 represents an alkyl radical or a hydrogen atom; Rio represents a phenyl or heteroaryl group optionally substituted by one or more halogen atoms or groups such as OH, -O-alkyl, -S-alkyl, cyano or alkyl;

R

1 and R 1 2 represent, independently of one another, a hydrogen or halogen atom or CN or NO 2

R

13 represents a halogen atom or a haloalkyl, haloalkyoxy, S(O)qCF3 or SF group; m, n, q and r represent, independently of one another, an integer equal to 0, 1 or 2; X represents a trivalent nitrogen atom or a C-R 12 radical, the three other valencies of the carbon atom forming part of the aromatic ring; S 15 with the proviso that, when RI is methyl, then R 3 is haloalkyl, R 4 is NH 2

R

11 is S. C1, R 13 is CF 3 and Xis N, in the manufacture of an agent for administration by an oral or parenteral route or topically with a transcutaneous effect to vertebrates to remove ectoparasites therefrom, wherein said compound is present in an effective amount for parasiticidal 20 control lasting at least one month in the absence of controlled release means.

According to another embodiment of the invention there is provided the use of a compound of formula (I)

*I

P:\OPERUgc51880-01 claims.doc-15/09/03 -3A- R2 R1

N

R4 N R1 (I)

\X

R13 in which: RI is a halogen atom, CN or methyl;

R

2 is S(O)nR 3 or haloalkyl;

R

3 is alkyl or haloalkyl;

R

4 represents a hydrogen or halogen atom; or an NR 5

R

6 S(O)mR 7

C(O)R

7 or C(O)OR 7 alkyl, haloalkyl or OR 8 radical or an N=C(R 9 (Ro 1 radical;

R

5 and R 6 independently represent a hydrogen atom or an alkyl, haloalkyl, alkoxycarbonyl, C(0)alkyl or S(O)rCF 3 radical; or R 5 and R 6 can together form a divalent alkylene radical which can be interrupted by one or two divalent heteroatoms;

R

7 represents an alkyl or haloalkyl radical; 15 R 8 represents an alkyl or haloalkyl radical or a hydrogen atom;

R

9 represents an alkyl radical or a hydrogen atom;

R

10 represents a phenyl or heteroaryl group optionally substituted by one or more halogen atoms or groups such as OH, -O-alkyl, -S-alkyl, cyano or alkyl;

R

11 and R 12 represent, independently of one another, a hydrogen or halogen atom or CN or NO 2

R

13 represents a halogen atom or a haloalkyl, haloalkyoxy, S(O)qCF3 or SF 5 group; 3b m, n, q and r represent, independently of one another, an integer equal to 0, 1 or 2; X represents a trivalent nitrogen atom or a C-R 12 radical, the three other valencies of the carbon atom forming part of the aromatic ring; with the proviso that, when R 1 is methyl, then R 3 is haloalkyl, R 4 is NH 2

R

1 is Cl, R 1 3 is CF 3 and X is N, to remove ectoparasites from vertebrates by administration by an oral or parenteral route or topically with a transcutaneous effect and in an effective amount for parasitical control lasting at least one month in the absence of controlled release means.

The alkyl radicals of the definition of the formula generally comprise from 1 S to 6 carbon atoms. The ring formed by the divalent alkylene radical representing Rs and R* 6 R and the nitrogen atom to which R 5 and R 6 are attached is generally a 6- or 7membered ring.

R

5 and R 6 can in particular independently represent the hydrogen atom or an 15 alkyl, haloalkyl, C(O)alkyl or S(O)rCF 3 radical; or Rs and R 6 can together 4 m:kspecifications\500000\502000\5021 94cimhxg.doc 4 form a divalent alkylene radical which can be interrupted by one or two divalent heteroatoms, such as oxygen or sulphur.

A preferred class of compounds of formula (I) comprises the compounds such that R, is CN and/or R 3 is haloalkyl and/or R 4 is NH 2 and/or R 11 and R 1 2 are, independently of one another, a halogen atom and/or R 13 is haloalkyl, preferably CF,.

Preference is also given to the compounds in which R 2 is S(O)nR 3 preferentially with n 1, R 3 preferably being CF 3 or alkyl, for example methyl or ethyl, or alternatively n 0, R 3 preferably being CF 3 A compound of formula which is very particularly preferred in the invention is 1- [2,6-Cl2-4-CF3phenyl]-3-CN-4- [SO-CF] -5-NH2pyrazole, hereinafter known as compound A and the common name of which is fipronil.

Another advantageous compound, in particular for oral administration, is 1-[2,6-C1 2 -4-CF 3 phenyl]-3- CN-4- S-CF 3 NHpyrazole. Another advantageous compound, for example, is 1-[2,6-Cl 2 -4-CF 3 phenyl]-3-CN- 4- [S-CH s -5 NHpyrazole.

Compounds of formula can be prepared according to one or other of the methods described in o. 25 Patent Applications WO 87/3781, 93/6089 and 94/21606 or European Patent Application 295,117 or any other method coming within the competence of the person skilled in the art who is a specialist in chemical synthesis. For *ee.

the chemical preparation of the products of the invention, the person skilled in the art is regarded as having available, inter alia, all the contents of "Chemical Abstracts" and of the documents which are cited therein.

Effectively parasiticidal amount is understood to mean an amount which results in blood and/or tissue concentrations which are toxic by ingestion by parasitic arthropods, in particular biting, sucking or gnawing arthropods.

5 In an improvement of the invention, it is possible to administer one or more other relevant parasiticides, concomitantly or simultaneously and preferably in the form of a single preparation. Such another parasiticide will preferably be an endectocidal parasiticide of macrocyclic lactone type.

This associated parasiticide is preferably selected from the group formed by avermectins, ivermectin, abamectin, doramectin, toxidectin, milbemycins and the derivatives of these compounds.

According to a preferred embodiment of the invention, the administration of the effective dose to the animal is carried out once or a very small number of times for a duration of activity of at least one month and which can advantageously be two or three months or even six months. In other words, a permanent combatting method in an environment in which the animal is subjected to strong parasitic pressure, wherein a systemic administration is carried out at a frequency well below a daily administration, such as, for example, a monthly administration, or even less than a monthly frequency, for example quarterly or halfyearly.

Moreover, it is particularly noteworthy and 25 surprising to be able to act effectively and for such long periods of time against ectoparasites which live in the integuments or on the fur of the animal by the administration of relatively low and non-toxic doses by systemic administration, without requiring the 30 employment of controlled and long-lasting release means. The explanation for this phenomenon is not, for the moment, fully understood but seems related to the combination of a very long persistence of the compound "I with an exceptional toxicity by ingestion by the parasite.

The effective dose administered in the method according to the invention is preferably between 0.001, preferentially 0.01, and 100 mg/kg and, in a particularly preferred way, from 1 to 50 mg/kg of 6 animal weight, the highest doses being provided for a very sustained release in the body of the animal.

Preferably, for the majority of host species, the dose and the composition are chosen so as to maintain a serum level of compound according to the formula of greater than or equal to 1 ng/ml, for example 1 to 50 ng/ml.

The methods according to the invention are particularly effective in combatting fleas and ticks of small companion animals, in particular dogs. Serum levels of 20 to 30 ng/ml will be preferred against fleas and of 30 to 50 ng/ml against ticks.

The methods are also particularly effective against ticks, flies and myiasis-causing parasites which parasitize large animals and in particular cattle, goats and sheep.

The methods have also proved to be particularly effective in the treatment of porcine mange.

The dose can be administered in particular by the oral or parenteral route or by a topical formulation with a transcutaneous effect.

A particular subject of the invention is *therapeutic methods according to the invention, intended for the treatment or prevention of parasitoses 25 having pathogenic consequences, wherein, for example, they are applied in the elimination of myiasis-causing parasites, in particular in cattle, horses, goats or sheep, in regions where a significant pressure from these myiasis-causing parasites exists, or in the elimination of ticks, in particular in cattle, or optionally dogs, in regions where the pressure from ticks is of such a nature as to result in pathogenic consequences on a significant scale.

oo ~Another subject of the invention is methods with a non-therapeutic purpose, in particular for cleaning the coats of animals, and in particular dogs and companion animals, which are thus rid of parasites, in particular fleas, and their waste and excreta. The 7 treated animal exhibits a coat which is pleasing to the eye and pleasant to the touch.

Other non-therapeutic methods according to the invention are applied, for example, in _combatting 'harmful flies, in companion animals or income-producing animals, in particular raised under intensive conditions or in herds.

Another subject of the invention is compositions for the implementation of methods with a therapeutic purpose according to the invention.

Another subject of the invention is compositions for the implementation of non-therapeutic methods according to the invention, in particular for cleaning coats.

The compositions according to the invention are preferably provided for administration in a single dose or a dose repeated a small number of times and preferably comprise a dose of compound of formula (I) of between 0.01 and 100 mg/kg and preferably 1 to 50 mg/kg of body weight of the animal.

The compositions are effective over a fairly wide range of doses, which makes it possible to provide the same dosages for small animals having relatively different sizes.

For administration by the oral route, the composition can optionally be prepared at the time of use, for example by simple mixing of a powdered, or preferably dissolved, preparation of a compound of formula into the food of the animal and in eoo 30 particular food prepared for dogs or cats. Use will preferably be made of the derivative of formula II.

8

/CH

3 CF The composition can, however, also be provided in any other form suitable for oral administration, such as, for example, solutions or suspensions to be taken orally, emulsions, microemulsions, creams, pellets, tablets, gelatin capsules or others.

It is preferable for the excipient which forms part of the composition for oral administration to allow release in the intestines, and gastroprotected gelatin capsules or gastroresistant tablets are particularly preferred.

For large animals, preference is given to formulations in the form of powders, of rumen-resistant formulations, boli or intraruminal devices.

For administration by the parenteral route, preferably the subcutaneous or intramuscular route, the compoundl of formula can be contained in a liquid excipient which is biologically suitable for injection 20 in the solution, suspension, emulsion or microemulsion form.

The parenteral composition can also be produced in the particulate form, in particular nanoparticles and nanocapsules, microparticles, microcapsules or 25 liposomes, or alternatively in the form of an implant.

The composition according to the invention can be presented in the form of a single dose without controlled release means. In this case, the dose is preferably between 1 and 20 mg/kg of body weight, which makes possible a long-lasting activity of several weeks to several months, which is altogether remarkable.

9 The compound of formula can also be contained in a material which provides for controlled release. For example, the compound according to the invention can be contained in microspheres, granules or implants which make possible release by diffusion and/or erosion.

A releasable composition with a dose of between 1 and 50 mg/kg, preferably of 10 to 30 mg/kg, for example 20 mg/kg of body weight, consequently makes possible a long-lasting activity for several months, indeed a year.

Such controlled-release formulations are particularly suitable for administration by the parenteral route, for example by injection. They are particularly suitable for the case of cats or other animals with a rapid metabolization.

For transcutaneous-passage formulations, the composition can comprise the abovementioned particulate or liposomal forms, preferably in combination with an absorption promoter.

In an improvement of the invention, the composition according to the invention can also comprise at least one other relevant parasiticide. This parasiticide will preferably be an endectocidal 25 parasiticide of macrocyclic lactone type.

This parasiticide is preferably selected from the group formed by avermectins, ivermectin, abamectin, doramectin, moxidectin, milbemycins and the derivatives of these compounds.

30 The effective amount of the endectocide in a dose is preferably between 0.1 mg/kg, preferentially 1 mg/kg, and 1 mg/kg, and, in a particularly preferred way, from 1 to 200 mg/kg of animal weight.

The proportions by weight of parasiticide of formula to the associated parasiticide are preferably between 5/1 and 20,000/1.

It can be particularly advantageous for the parasiticide of formula and the associated endectocidal parasiticide to be contained in a 10 controlled- and sustained-release preparation, such as, for example, microspheres, granules or implants. This can. be obtained, preferably, by mixing a controlledrelease preparation of product, such as fipronil, and a controlled-release preparation of endectocide, preferably ivermectin, in a suitable vehicle, such as water, oil or a medium-chain triglyceride.

In such controlled-release preparations, the formulations are preferably drawn up so as to release between 5 and 100 mg/kg/day, for example 45 mg/kg/day, of compound of formula for example fipronil, and from 0.01 to 15 mg/kg/day, for example 0.5 mg/kg/day, of endectocide, in particular ivermectin.

In the case of such controlled-release preparations, a dose for a treatment of very long duration of an animal will preferably comprise between 1 and 20 mg/kg of fipronil or other product of formula and between 2 mg/kg and 3 mg/kg of endectocide, in particular of ivermectin.

Another subject of the invention is the use of the abovementioned compound corresponding to the formula for the preparation of the compositions capable of being employed in the methods according to the invention. Among the compounds which it is preferable to use for this end is 1-[2,6-C1 2 -4-

CF

3 phenyl] -3-CN-4- [SO-CF 3 ]-5-NH 2 pyrazole (fipronil).

Other advantages and characteristics of the S. invention will become apparent on reading the following description, given by way of non-limiting example.

S. Example 1 Sixteen pigs, with an average weight of 21 kg, .naturally infested with sarcoptic mange (Sarcoptes scabiei, variety suis) were randomly divided into 4 groups of 4 pigs each (1 untreated control group, 3 treatment groups).

The fipronil-based treatment was mixed with the food and administered once on day .0 at doses of 6.25 and 25 mg/kg to the 3 treatment groups.

11 All the pigs were heavily infested by the agent of sarcoptic mange (scraping until blood emerges, then microscopic examination) and showed visible clinical signs of this infestation, of the blotches of the skin, pruritus and papules type.

Clinical and parasitological examinations carried out each week after treatment for 1 month showed 100% effectiveness in the treated groups whereas the sarcoptic mange persists in the untreated animals.

Example .2 Twenty dogs of various breeds were randomly assigned to 4 groups of five animals each. A first group was used as untreated control. In the 3 other groups, each dog was treated once at DO by the oral route with fipronil in the gelatin-capsule form at doses of 1, 10 and 20 mg/kg respectively in each group.

These animals were 'experimentally infested with 100 fleas (Ctenocephal ides felis) and 50 ticks (Rhipicephalus sanguineus) at Dl, D7 and weekly thereafter until 42 days after treatment.

Fleas and ticks were counted 2 days after each experimental infestation in order to evaluate the insecticidal activity in the treated groups.

A dose-duration of activity response was clearly demonstrated, i.e.: At the dose of 1 mg/kg, look flea control was obtained for 2 weeks and look tick control was obtained for 1 week.

At the dose of 10 mg/kg, 100% f lea control was obtained for 3 weeks and 100% tick control was obtained for 1 week.

At the dose of 20 mg/kg, 100% flea control was obtained for 5 weeks and 100% tick control was obtained for 2 weeks.

In addition to the dose-effect response demonstrated, this method made it possible to reveal that the systemic activity of fipronil by the oral 12 route was superior in duration against the flea in comparison with the tick.

Example 3 A group of 3 dogs weighing 10 kg is treated with a 3.3% m/V solution of fipronil in a mixture of organic solvents and of vegetable oil by the subcutaneous route at the rate of 0.3 ml/kg.

Minimum effective plasma concentrations are obtained for a duration of at least 3 months (fleas and ticks).

Example 4 Four groups of 3 dogs weighing 10 kg are treated with microspheres made of poly(lactic acid) or poly(lactic-glycolic acid) polymer which make possible controlled release of fipronil. The polymer which confines the fipronil can be in particular PLA 100 D.L with a molecular weight of 100,000, PLA 100 D.L. with a weight of 26,000, PLGA 75/25 with a weight of 19,000 or PLGA 75/25 with a weight of 120,000, approximately, at 15% m/V in water or in a vegetable oil or in a mediumchain triglyceride 3.3% m/V of fipronil) by the subcutaneous route at the rate of 0.3 ml/kg.

25 The fipronil dose administered is thus approximately 9 mg/kg.

Depending on the formulations injected, minimum effective plasma concentrations are obtained for durations of at least 2 months to 6 to 7 months (fleas and ticks).

Example A preparation of microspheres containing fipronil is prepared according to Example 4.

Microspheres containing ivermectin are prepared separately. Such microspheres can be prepared in a way known per se, for example as described in Application WO 95/13799. These microspheres are preferably contained in the same liquid vehicle as the 13 microspheres containing fipronil, namely water, a vegetable oil or a medium-chain triglyceride.

The two preparations are mixed in proportions such that the injectable dose contains 9 mg of fipronil and. 200. .mg of ivermectin/kg and the dose is administered to 4 groups of 3 dogs.

Throughout this specification and claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that the prior art forms part of the common general knowledge in Australia.

***ee o o e

Claims (76)

1. Use of a compound of formula (I) R 2 R R m *4 R 13 in which: R 1 is a halogen atom, CN or methyl; R 2 is S(O)nR 3 or haloalkyl; 4 *R 3 is alkyl or haloalkyl; R 4 represents-a hydrogen or halogen atom; or an NR 5 R 6 10 S(O)mR 7 C(O)R 7 or C(O)OR 7 alkyl, haloalkyl or OR 8 radical or an N=C(R9) (R10) radical; R5 and R6 idependently represent a hydrogen atom or an alkyl, haloalkyl, alkoxycarbonyl, C(O)alkyl or S(O)rCF 3 radical; or R 5 and R 6 can together form a divalent alkylene radical which can be interrupted by one or two divalent heteroatoms; R 7 represents an alkyl or haloalkyl radical; R 8 represents an alkyl or haloalkyl radical or a hydrogen atom; R 9 represents an alkyl radical or a hydrogen atom; R 10 represents a phenyl or heteroaryl group optionally substituted by one or more halogen atoms or groups; R 1 1 and R12 represent, independently of one another, a hydrogen or halogen atom or CN or NO 2 R 13 represents a halogen atom or a haloalkyl, haloalkyoxy, S(O)qCF3 or SFs group; m, n, q and r represent, independently of one another, an integer equal to 0, 1 or 2; X represents a trivalent nitrogen atom or a C-RI 2 radical, the three other valencies of the carbon atom forming part of the aromatic ring; with the proviso that, when R 1 is methyl, then R 3 is haloalkyl, R 4 is NH 2 R 11 is Cl, R 1 3 is CF 3 and X is N, in the manufacture of an agent for administration by an oral or parenteral route 10 or topically with a transcutaneous effect to vertebrates to remove ectoparasites therefrom, wherein said compound is present in an effective amount for parasiticidal •control lasting at least one month in the absence of controlled release means.

2. The use as claimed in claim 1 wherein said vertebrates are mammals.

3. The use as claimed in claim 1 or claim 2 wherein said ectoparasites are arthropods.

4. The use as claimed in claim 1 or claim 2 wherein said ectoparasites are insects and Arachnida.

5. The use as claimed in claim 1 wherein R 11 and R 1 2 are, independently of one another, H or halogen.

6. The use as claimed in claim 1 wherein said compound of formula is such that RI is CN and/or R 3 is haloalkyl and/or R 4 is NH 2 and/or R 11 and R 1 2 are, independently of one another, a halogen atom and/or RI3 is haloalkyl. m:\specifications\500000\502000\5021 94cmhxg.doc -16-

7. The use as claimed in claim 6 wherein the compound is 6-Cl 2 -4-CF 3 -phenyl]-3-CN-4-[SO-CF 3 ]-5-NH 2 -pyrazole]

8. The use as claimed in any one of claims 1 to 6 wherein the compound of formula is such that R 2 is S(O)nR 3

9. The use as claimed in claim 8 wherein n=l.

10. The use as claimed in claim 9 wherein R 3 is CF 3 or alkyl.

11. The use as claimed in claim 10 where.in R 3 is methyl or ethyl. 15 o 0o

12. The use as claimed in claim 8 wherein n=0.

13. The use as claimed in claim 12 wherein R 3 is CF 3

14. The use as claimed in any one of claims 1 to 13 wherein the dose is administered to the vertebrate at a monthly frequency or less frequently. The use as claimed in claim 14 wherein said frequency is two or three or six months.

16. The use as claimed in any one of claims 1 to wherein said effective dose is between 1 to 50 mg/kg of weight of the vertebrate.

17. The use as claimed in claim 16 wherein an effective dose of 20 mg/kg of weight of the vertebrate is; administered. 0 0 -17-

18. The use as claimed in any one of claims 1 to 17 wherein said agent provides a serum level of compound of formula of greater than or equal to 1 mg/ml.

19. The use as claimed in any one of claims 1 to 18 wherein a dose is selected to maintain a serum level of to 30 mg/ml against fleas or of 30 to 50 mg/ml.. against. ticks Sin small vertebrates.

20. The use as claimed in any one of claims 1 to 19 wherein the agent is formulated for administration by..an oral or parenteral route.

21. The use as claimed in any one of claims 1 to 20 wherein said agent is produced in the form. of a single

22. The use as claimed in claim 21 wherein said. agent contains a dose of the said compound of between 0.001 and 100 mg/kg of body weight of the vertebrates.

23. The use as claimed in claim 22 wherein dose of said agent is between 0.01 and 100 mg/kg of body weight of the vertebrate.

24. The use as claimed in claim 23 wherein dose of said agent is between 1 and 50 mg/kg of body weight of the vertebrate.

25. The use as claimed in claim 24 wherein said dose is between 10 and 20 mg/kg. 24/03 '04 13:51 FAX 61 3 9663 3099 FB RICE CO. @1007 I j ;18

26. Tie use as claimed in any one of claims 21 to 25 wherein said agent is fom latLd for oral administration. I,

27. The use as claimed in claim 26 wherein it is packaged for release in the intesdin&s.

28. le use as claimed in claim 27 wherein said agent is in the form of gastr pr tected gelatin capsules or gastroresistant tablets.

29. The use as claimed in any one of claims 21 to 25 wherein said agent contains an excipierit which is suitable for parenteral administration. a i o

30. 1he use as claimed in claim 29 wherein said excipient is suitable for injection. 15 31. the use as claimed in claim 29 or claim 30 wherein said agent contains a biologi ally acceptable liquid vehicle.

32. ihIe use as claimed in claim 28 wherein said agent is in the form of a gastr protected gelatin capsule. i...i 20 The use as claimed in any one of claims 29 to 31 wherein said compound is combined with an oily adjuvant. i I

34. h6 use as claimed in any one of claims 21 to 25 wherein said compound is 25 containid in a topical vehicle for transcutaneous passage. i, I, I, COMS ID No: SMBI-00678566 Received by IP Australia: Time 13:51 Date 2004-03-24 -19- The use as claimed in any one of claims 20 to 28 wherein said compound is of formula (II) 0. (II) CH 3 5 36. The use as claimed in any one of claims 1 to 35 wherein said parasites are fleas and said vertebrates are cats, Sdogs, cattle, sheep and goats. See

37. The use as claimed in any one of claims 1 to 35 wherein 10 said parasites are ticks and said vertebrates are cats and dogs. 0 38. The use as claimed in any one of claims 1 to 35 wherein said parasites are myiasis-causing parasites and said vertebrates are cattle, goats and sheep.

39. The use as claimed in any one of claims 1 to 35 wherein said parasites are harmful flies.

40. The use as claimed in any one of claims 1 to 35 wherein said parasites are sarcoptic mange and said vertebrates are pigs.

41. The use as claimed in claim 36 wherein said parasites are fleas and said vertebrates are cats and dogs. 0 0

42. The use as claimed in claim 1 substantially as hereinbefore described.

43. Use of a compound of formula (I) R 2 R *N R• N "x R* in which: RI is a halogen atom, CN or methyl; i htr R 2 is S(O)nR 3 or haloalkyl;. 1: 0 R 3 is alkyl or haloalkyl; R 4 represents a hydrogen or halogen atom; or an NR 5 R, S(O)mR 7 C(O)R7 or C(0)OR 7 alkyl, haloalkyl or OR 8 radical or an N=C(R 9 (Rio) radical; R 5 and R 6 independently represent a hydrogen atom or an alkyl, haloalkyl, alkoxycarbonyl, C(O)alkyl or S(O)rCF 3 radical; or R 5 and R 6 can together form a divalent alkylene radical which can be interrupted by one or two divalent heteroatoms; R7 represents an alkyl or haloalkyl radical; R 8 represents an alkyl or haloalkyl radical or a hydrogen atom; R 9 represents an alkyl radical or a hydrogen atom; R 10 represents a phenyl or heteroaryl group optionally substituted by one or more halogen atoms or groups; __0 21 RI 1 and R 12 represent, independently of one another, a hydrogen or halogen atom or CN or NO 2 R 1 3 represents a halogen atom or a haloalkyl, haloalkyoxy, S(O)qCF3 or SFs group; m, n, q and r represent, independently of one another, an integer equal to 0, 1 or 2; X represents a trivalent nitrogen atom or a C-RI 2 radical, the three other valencies of the carbon atom forming part of the aromatic ring; with the proviso that, when RI is methyl, then R 3 is haloalkyl, R4 is NH 2 R 11 is 10 Cl, R3 isCF 3 andXisN, to remove ectoparasites from vertebrates by administration by an oral or parenteral route or topically with a transcutaneous effect and in an effective amount for parasitical control lasting at least one month in the absence of controlled release means. r 15 44. The use as claimed in claim 43 wherein said vertebrates are mammals.

45. The use as claimed in claim 43 or claim 44 wherein said ectoparasites are arthropods. 20 46. The use as claimed in claim 43 or claim 44 wherein said ectoparasites are insects and Arachnida. .o

47. The use as claimed in claim 43 wherein Rn 1 and R 12 are, independently of one another, H or halogen.

48. The use as claimed in claim 43 wherein said compound of formula is such that Ri is CN and/or R 3 is haloalkyl and/or R 9 is NH 2 and/or R 11 and R 1 2 are, independently of one another, a halogen atom and/or R 13 is haloalkyl. m:\specifications\500000\502000\5021 94cmhxg.doc -22-

49. The use as claimed in claim 48 wherein the compound is 1-[2,6-C1 2 -4-CF 3 -phenyl]-3-CN-4-[SO-CF 3 ]-5-NH 2 -pyrazole].

50. The use as claimed in any one of claims 43 to 48 wherein the compound of formula is such that R 2 is S(0)nR 3

51. The use as claimed in claim 50 wherein n=l. e

52. The use as claimed in claim 51 wherein R 3 is CF 3 or S .alkyl..

53. The use as claimed in claim 52 wherein R 3 is methyl or 15 ethyl. S: 54. The use as claimed in claim 50 wherein n=0.

55. The use as claimed in claim 54 wherein R 3 is CF 3

56. The use as claimed in any one. of claims 43 to wherein the dose is administered to the vertebrate at a monthly frequency or less frequently.

57. The use as claimed in claim 56 wherein said frequency is two or three or six months.

58. The use as claimed in any one of. claims 43 to 57 wherein said effective dose is between 1 to 50 mg/kg of weight of the vertebrate. -23-

59. The use as claimed in claim 58 wherein an effective dose of 20 mg/kg of weight of the vertebrate is administered.

60. The use as claimed in any one of claims 43 to 59 wherein said agent provides a serum level of compound of formula of greater than or equal to 1 mg/ml.

61. The use as claimed in any one of claims 43 to 10 wherein a dose is selected to maintain a serum level of to 30 mg/ml against fleas or of 30 to 50 mg/ml against ticks in small vertebrates.

62. The use as claimed in any one of claims 43 to 61 15 wherein the agent is formulated for administration by an oral or parenteral route.

63. The use as claimed in any one of claims 43 to 62 wherein said agent is produced in the form of a single dose. S.

64. The use as claimed in claim 63 wherein said agent contains a dose of the said compound of between 0.001 and 100 mg/kg of body weight of the vertebrates.

65. The use as claimed in claim 64 wherein dose of said agent is between 0.01 and 100 mg/kg of body weight of the vertebrate.

66. The use as claimed in claim 65 wherein dose of said agent is between 1 and 50 mg/kg of body weight of the vertebrate. 24/03 '04 13:51 FAX 61 3 9663 3099 FB RICE CO.- 6008 l 24 i'

67. The use as claimed in claim 66 wherein said dose is between 10 and 20 mg/kg,

68. the use as claimed in any one of claims 63 to 67 wherein said agent is formlaed for oral administration.

69. I the use as claimed in claim 68 wherein it is packaged for release in the intestines, i use as claimed in claim 69 wherein said agent is in the form of gasttopvotected gelatin capsules or gastroresistant tablets.

71. The use as claimed in any one of claims 63 to 67 wherein said agent contains an excij)ieit which is suitable for parenteral administration. 00* 15 72. The use as claimed in claim 71 wherein said excipient is suitable for injection.

73. The use as claimed in claim 70 or claim 71 wherein said agent contains a S" biol6 gi"ally acceptable liquid vehicle. 0 II 0000 .0 20 74. The use as claimed in claim 70 wherein said agent is in the form of "gastroprotected gelatin capsules.

75. The use as claimed in any one of claims 70 to 72 wherein said compound is .e *coffbind with an oily adjuvant. 0000 25

76. The use as claimed in any one of claims 63 to 67 wherein said compound is conainNd in a topical vehicle for I COMS ID No: SMBI-00678566 Received by IP Australia: Time 13:51 Date 2004-03-24 0 transcutaneous passage.

77. The use as claimed in any one of claims 62 to wherein said compound is of formula (II) 0 0 0 0 0 0 0 0 *9 9 9*

78. The use as claimed in any one of claims 43 to 77 wherein said parasites are fleas and said vertebrates are cats, dogs, cattle, sheep and goats.

79. The use as claimed in any one of claims 43 to 77 wherein said parasites are ticks and said vertebrates are cats and.dogs.

80. The use as claimed in any one of claims 43 to 77 wherein said parasites are myiasis-causing parasites and said vertebrates are cattle, goats and sheep.

81. The use as claimed in any one of claims 43 to 77 wherein said parasites are harmful flies.

82. The use as claimed in any one of claims 43 to 77 wherein said parasites are sarcoptic mange and said vertebrates are pigs. -26-

83. The use as claimed in claim 78 wherein said parasites are fleas and said vertebrates are cats and dogs.

84. The use as claimed in claim 43 substantially as hereinbefore described. The use as claimed in claim 1 in which Rs and R 6 together form a divalent alkylene radical which can be interrupted by one or two divalent heteroatoms selected from oxygen and sulphur.

86. The use as claimed in claim. 1 wherein Rio represents a phenyl or heteroaryl group optionally substituted by one or more halogen atoms or groups selected from. OH, -O-alkyl, -S-alkyl, cyano and alkyl.

87. The use as claimed in claim 43 in which Rs and R 6 S: together form a divalent alkylene radical which can be interrupted by one or two divalent heteroatoms selected from 20 oxygen and sulphur.

88. The use as claimed in claim 43 wherein Rio represents a phenyl or heteroaryl group optionally substituted.by one or more halogen atoms or groups selected from OH, -O-alkyl, -S-alkyl, cyano and alkyl. 24/03 '04 13:52 FAX 61 3 9663 3099 FB RICE CO. 11 009 27 89, i Te use of a compound according to claims 1 or 43 substantially as hereinbefore described with reference to the preferred embodiments and/or the examples, and exclu in, if any, comparative examples, I I Dated ts twenty-fourth day of March 2004 I I Merial Patent Attorneys for the Applicant: S 0

900. 0@ A. P A. C C S *:0 0 4.0 C F B RICE CO m:spedflcations\50000050200 0 50 2 194clmhxgc24.doc COMS ID No: SMBI-00678566 Received by IP Australia: Time 13:51 Date 2004-03-24