GB2114442A - Improvements in or to anti-parasite collars for animals - Google Patents

Abstract

Anti-parasite collars for animals include an insecticidal device formed from at least one insecticidal substance associated with at least one substance selected from among C18 to C22 unsaturated essential fatty acids. This collar can be in the form of a strap, or in the form of a mixed double strap formed from two laterally bonded strips, one strip containing the insecticidal substance, the other the unsaturated essential fatty acid.

Description

SPECIFICATION Anti-parasite collar BACKGROUND OF THE INVENTION Field of the invention The present invention relates to improvements in orto anti-parasite collars for animals. For a certain time already there have been used, devices adapted to release gradually a contact insecticide intended for the protection of animals against parasites and in particular against ectoparasites. The majority of these devices are constituted by an insecticide included in a matrix of plastics material. The slow release of the ectoparasiticide product (which acts through its vapour or which is deposited on the hair of the animal) permits effective protection against parasites for several months.

Description of the prior art These various anti-parasitic devices and which have been the subject of very many patents (particularly French patents of Applicant 2,447,679,2,268,859, 2,307,466,2,436,563, 2,370,572,2,213,014, 2,374,853, 2,386,253,2,386,254, 2,392,606), are essentially composed of three basic elements: - the insecticide (or mixture of insecticides), - the support (generally based on a thermoplastic resin), - the adjuvants (like plasticisers, diffusion regulators, etc...) The choice of each of these basic constituents is very important. It is in fact imperative to have a device effective against parasites, diffusing slowly and regularly and completely innocuous for both the animal and its surroundings, and particularly for young children.

If the majority of the drawbacks of these anti-parasitic collars have been eliminated and difficulties of all sorts overcome, there remains however one drawback which is of great importance. The animal, very rapidly or after a certain period of use, has allergic phenomena manifested by locai disorders: redness of the skin, eczemas, blemishment of the hair, loss of suppleness of the sin etc.. and/or by general disorders : vomiting, weight loss, etc...

It is consequently an object of the present invention to provide ectoparasitic devices and collars which respond better to the necessities of practice than previously known devices designed for the same purpose, particularly in that they eliminate entirely the cutaneous disorders of the animal, whilst retaining high efficacity of action over a long period.

General description of the invention According to the present invention there is provided an anti-parasitic collar for animals, comprising an insecticide device formed from at least one insecticidal substance associated with at least one substance selected from among unsaturated essential fatty acids of C18 to C22 and their esters.

The very great experience of Applicant in the field of combating parasites of animals, has enabled the observation that in the long run intolerance to the insecticidal collar was due to deficiency of certain fatty acids necessary for the epithelial system of the animal.

In accordance with the invention, the anti-parasitic device is composed, in addition, of the following two elements: - a thermoplastic solid macromolecular support, - adjuvants (plasticisers and/or inert fillers, and/or dyes and/or deodorisers, and/or stabilisers, and/or diffusion regulators).

In a preferred embodiment of the invention, the insecticidal substance is selected from among organochlorine compounds and/or organophosphorus compounds and/or carbamates, and/or pyrethrums and/or formamidines.

According to a particular variant of this embodiment, the organochlorine substances are selected from the group which comprises: - 2,2-dichlorovinyl phosphate and dimethyl phosphate (DDVP) - 1,2-dibromo-2,2-dichloroethyl phosphate and methyl phosphate (NALED), - 2-chloro,(2,4,5-trichlorophenyl)-vinyl phosphate and dimethyl phosphate (STIRIFOS).

According to another particular variant, the organophosphorous substance is selected from the group which comprises O,O'-diethyl,O-(isopropyl-2 methyl-4 pyrimidinyl-6)thionophosphate (DIMPYLATE) and O,O-diethyl,O-(isopropyl-2 methyl-4 pyrimidinyl-6) phosphate (DIAZOXON).

According to another particular embodiment, the carbamates are selected from among dimethyl-2 2 benzodioxoi-1,3 ol-4 N-methyl carbamate (BENDIOCARD), isopropoxy-2 phenyl N-methyl carbamate (PROPOXUR), 1-naphthyl N-methyl carbamate (CARBARYL).

According to another particular variant, the substances of pyrethum type are selected from among -cyano-3 phenoxybenzyl 2,2-dimethyl 3-(2,2-dichlorovinyl) cyclo-propane carboxylate (CYPERMETHRIN), -cyano-3 phenoxy-benzyl 2-(4-chlorophenyl) 3 methyl butyrate (FENVALERATE), 5-benzyl, 3 furylmethyl 2,2-dimethyl 3-(2-oxo 2,3,4,5 tetrahydro 3-thienylidenemethyl) cyclopropane carboxylate (KADETHRINE), 3-phenoxybenzyl 2,2-dimethyl, 3-(2,2-dichlorovinyl) cyclopropane carboxylate jPERMETHRINE), (3,4,5,6 tretrahydrophtalimidomethyl) chrysanthemate (NEOPYNAMIN).

According to another particular variant, the formamidines are selected from among N'-(4-chloro 0 tolyl) NN, dimethylformamidine (CHLORDIMEFORM), and N-methyl, N' 2,4xylyl N (N 2,4 xyllylformamidoyl) formamidine (AMITRAZ).

According to the invention, the free or esterified unsaturated essential fatty acids are selected from the group which comprises oleic acid, linoleic acid, linolenic acid, arachidonic acid, 11,14 eicosadienoic acid, docosahexaenoic acid and their C1 to C4 linear or branched esters.

According to another particularly preferred embodiment, as fatty acids, vitamin F is used.

As thermoplastic solid macromolecular support, there may be used, for example, polyethylene, polypropylene, copolymers of ethylene and propylene, polyacrylates, vinyl polymers, polyvinyl halides, polyvinyl acetals, compounds of the polyvinylidenetype, polyurethanes, polyaldehydes, etc..., and preferably homopolymers of polyvinyl chlorides or their copolymers with other polymers.

As plasticisers necessary to confer suppleness, the mechanical strength and the desired surface characteristics, it is possible to use, for example, the esters of phosphoric acid, such as tricresyl phosphate, the esters phthalic acid such as methyl, butyl, octyl, ethyl-2-hexyl, esters of adipic acids, azelaic, sebacic, maleic acids, etc...

The additives most commonly added, are dyes or pitments, deodorisers such as ethylvanilla, vanillin, limonene, etc.; stabilisers, lubricants, metal complexes (of cadmium, barium and zinc, for example); diffusion regulators which act by modifying the porosity of the plastic strip, by vaporisation or decom posation during manufacture, for example nitrogen derivatives (benzenesulfonyl hydrazine, trihydrazinotriazine, etc..) and the azo derivatives (azodiisobutyronitrile, diazoaminobenzene, azodicarbonamide, etc...) As fillers necessary to reduce the amount of resin and facilitate the employment of the thermoplastic strip, talc, silica, etc... may be used.

According to the invention, the composition of the antiparasitic device comprises from 5 to 25% of insecticidal substance, from 1 to 10% of unsaturated essential fatty acid, from 10 to 50% of macromolecular support and from 1 to 15% of various adjuvants.

According to a particularly advantageous embodiment of the invention, the insecticidal substances associated with the fatty acid is DIMPYLATE associated with vitamin F.

In pursuing the research further, Applicant has observed that in certain cases, the physicochemical nature of the active substances such as particularly the physical appearance, -solid or liquid-, the melting point, the boiling point, the vapor pressure, the thermal or chemical stability etc... did not permit regular and identical diffusion of the two substances at the same time.

This diffusion speed can vary even in certain cases to a large proportion. It becomes indispensable, in certain cases, to take into account the physicochemical properties of the active substances (insecticide and fatty acid) in order to select a suitable macromolecular support, plastisisers, additives, fillers and suitable diffusion regulators, so as to realise a compromise and to have elimination speeds of the two active substances as close as possible, if not substantially identical.

One of the objects of the present invention is to produce an antiparasite collar so as to be able to be free of the restrictions that could be imposed in certain cases by the incompatibiiity between the active substance and an unsaturated essential fatty acid.

It is also an object of the present invention to provide an antiparasite collar for animals comprising an insecticide device formed from at least one insecticidal substance associated with at least one substance selected from among unsaturated essential fatty acids of C18 to C22, characterised by the fact that it is in the form of two strips coupled together laterally to form a mixed double strap, one strip containing the insecticidal substance, the other, the fatty acid, each of the two strip parts containing suitable supports and additives for the insecticidal substance and far the unsaturated essential fatty acid selected.

The production of two strips of plastics material each containing one of the active substances - the strips being bonded laterally - has enabled the exigencies of diffusion and elimination to be satisfied to the maximum.

According to a particularly advantageous embodiment of the invention, the mixed strap is obtained by hot co-extrusion.

According to another envolument of the invention, the mixed strap is obtained by molding. However, whatever the technical means for producing strips (co-extrusion or molding) it is very easy to adapt the nature of the excipients and the support to the physicochemical properties of each of the two active substances and thus to fix the operational conditions. As a result whilst preserving the quality of tolerance, described, the effectiveness of the antiparasitic device is much improved, and the restrictions of manufacture and hence cost price are reduced by the maximum amount.

Among the various possible techniques for producing these devices according to the present invention, the so-called hot co-extrusion technique constitutes, on the industrial production scale, the most suitable method.

The latter method, - at present very much used in the rubber and plastics materials industry - leads to the production by co-extrusion by the passage into a single extrusion head of a mixed strip from separate extrusion of two different mixtures.

By proceeding thus in the preparation of two separate mixtures and each suited in their composition to the nature of the active substance, a final more effective device is produced. This type of preparation is found to be especially desirable when the two active substances are very different in their physicochemical properties.

Thus if the C18 to C22 unsaturated essential fatty acids or their esterified derivatives are in the form of viscous liquids, the inseticidal substances applied in this invention may be liquid compounds (organochlorine, organophosphorus, pyrethrinoidal) or solid compounds (carbamates, formamidines).

In addition, each group of compounds is characterised also by different boiling points or melting points, very widely spaced vapor pressures as well as by different criteria of thermal or chemical stability.

Now, it is known to the technician skilled in the art that the nature of the macromolecular support, the nature of the plasticisers, the nature of the additives, influence considerably the speeds of the diffusion and hence of elimination, hence the measured activity.

Evidently, as a result the association of the carbamate and/or a formamidine with a fatty acid ester, will only give optimal results if the composition of each of the parts is different.

The result is judged optimal when the diffusion speeds of each of the compounds are similar.

For each type of substance used, it is hence necessary to adapt the nature of the adjuvants and/or of the supports so as to accelerate or retard the elimination of one of the compounds with respect to the other taken as reference.

In their apearance, the new devices are in the form of a mixed strap whose respectives dimensions of each part are established on the basis of various elements such as the percentage of active material, the insecticidal or protective activity of the substance; generaly, they must be compatible with the requirements of obtaining a strap which can be used as an antiparasite collar for domestic animals (dogs or cats).

In general the dimensions of the final strap will be suitable in the proximity of 15 to 30 mm for the width and the vicinity of 2 to 5 mm. for the thickness, the length being calculated so to be fixable on the neck of the larger animals.

It is evident that devices adapted in size for each type of animal, cat, puppy, dog, large dog, are preferable.

Taking into account the various percentages, namely from 5 to 25%, for the insecticidal substance and from 1 to 10% for the fatty acids, the respective widths of each of the parts will be different.

In general, the widths are from 10 to 20 mm for the insecticidal portion and from 5 to 10 mm. for the fatty acid portion.

The separate manufacture of each of the two mixtures permits incorporation of dye-stufs, pigments, or different photo-reflecting or luminescent substances for each of the parts.

Besides the foregoing features, the invention comprises still other features which will emerge from the description which follows.

The present invention is directed particularly to anti-parasite collars for animals, in accordance with the preceding features, as well as the means adapted for the production of these collars.

The invention will be better understood by means of the additional description which follows, which refers to embodiments of the devices according to the present invention, to examples of the composition of said devices, as well as to an account of clinical trials carried out on animals.

It must be well understood, however, that the examples of use which will be described below, as well as the clinical account, are given purely by way of illustration of the invention, but do not constitute in any way a limitation thereof.

Examples of composition Example 1 Parts by weight DIMPYLATE 15 Methyl linoleate Active 2 principle Methyl linolenate 3 Ethyl-2 hexyl adipate 20 Epoxydised soya oil 5 Calcium stearate Additive 2 Black iron oxide 0.5 Micronised silica 1.5 Azocarbonamide 2 polyvinyl chloride homopolymer 49 Example 2 DIMPYLATE 18 Active principle Neutral vitamin F 6 Isooctyle adipate 23 Epoxydised soya oil 3 Calcium stearate Additive 2 Red iron oxide 0.5 Micronised silica 2 Azodicarbonamide 2 PVC homopolymer 43.5 Example 3 BENDIOCARD 10 Methyl linoleate Active 1.5 principle Methyl linolenate 1.5 Methyl oleate 2 Butyl phthalate 15 Methyl phthalate 10 Epoxydised soya oil 5 Calcium stearate Additive 2 Red iron oxide 0.25 Black iron oxide 0.25 Azodicarbonamide 2 PVC homopolymer 50.5 Example 4 BENDIOCARD 8 Active principle Neutral vitamin F 6 Isooctyl adipate 10 Methyl adipate 15 Epoxydised soya oil Additive 5 Calcium stearate 2 Azodicarbonamide 2 PVC homopolymer 52 Example 5 CYPERMETHRIM 5 Active Methyl docosahexanoate acid principle 6 Butyl adipate 10 Methyl adipate 10 Calcium stearate Additive 2 Barium/cadmium complex 1 Micronised silica 2 Black iron oxide 0.5 PVC homopolymer 63.5 Example 6 FENVALERATE 6 Active principle Methyl linolenate 3 Isooctyl adipate 10 Methyl adipate 15 Epoxydised soya oil Additive 3 Calcium stearate 2 PVC homopolymer 61 Example 7 AMITRAZ 10 Active principle Neutral vitamin F 5 Ethyl-2-hexyl phthalate 12.5 Butyl phthalate 12.5 Epoxydised soya oil 5 Additive Calcium stearate 1.5 Black iron oxide 0.5 Red iron oxide 0.5 Azodicarbonamide 2.5 PVC homopolymer 50 Example of the manufacture of the collar The substances of Example 2 are used.

In a suitable recipient, there are mixed intimately 36 kg of DIMPYLATE, 12 kg of neutral vitamin F, 46 kg of isooctyl adipate, 6 kg of epoxydised soya oil and the solution is coloured with red iron oxide (about 1 kg).

In a heating mixer, are introduced 47 kg of PVC homopolymer, 4 kg of calcium stearate, 4 kg of micronised silica and 4 kg of azodicarbonamide.

The preceeding solution is poured with stirring into the above mixer. The dough obtained is mixed until a uniform red colour is obtained. The mixture is brought to a temperature of about 70"C, and stirred for 30 minutes. The powder so obtained is introduced into the hopper of a screw extruder. The extrusion parameters, namely the temperature of the extrusion head or die, the pressure of the die head, the extrusion speed and the cooling temperature, are fixed as to obtain a strap uniform in appearance and size.

The strap is then cut to length; a closure system is stapled to one end.

The insecticide collar obtained is packed in triple thickness packets (PVC - aluminum - paper) and heat-sealed.

This manufacturing procedure is valid for all examples, introducing therein the modifications due to the physical nature of the constituants.

Example ofmanufacture of a mixed double strap Two mixtures are prepared: The mixture A containing the insecticidal substance and the mixture B contaning the fatty acid.

These two mixtures (of which some different compositions will be described below) are, after homogenisation, introduced separately into the two hoppers of a double system extruder. At the outlet, the two strips precalibrated in dimensions pass into a common die head within which the lateral welding is effected.

This manufacturing step can also be carried out with the use of two different extruders, connected at the outlet by a single die head enabling the lateral bonding of the two initial straps and their final calibration to the format of the single strap.

The system has the advantage of being able to adjust, independently, the extrustion parameters such as temperature of the die, pressure and extrusion speed.

Example of composition: Example 8 Mixture A Parts by weight Dimpylate [O,O'-diethyl, Active 0- (isopropyl-2 methyl-4 principle 15 pyrimidinyl-6 thionophosphate] Epoxidised soya oil 3 Calcium stearate 2 Additive Ethyl-2 hexyl phthalate 20 Azodicarbonamide 2 Red iron oxide 0.25 Black iron oxide 0.25 PVC homopolymer 57.5 Mixture B Active Neutral vitamin F Principle 12 Epoxidised soya oil 3 Butyl phthalate 25 Yellow pigment 0.50 Additive Calcium carbonate 5 Calcium stearate 2 PVC homopolymer 52.50 Mixture A In a first container are mixed intimately 32 kg of 95 % Dimpylate, 6 kg of epoxidised soya oil, 40 kg of ethyl-2 hexyl phthalate and the solution is coloured by the mixture of the two iron oxides.

In a heating mixer, are introduced 50 kg of PVC hompolymer and 4 kg of azodicarbonamide.

Then with stirring the preceding solution is introduced into the mixer, it is heated for 30 min at 70"C, then it is completed by the remaining amount of PVC homopolymer. It is stirred whilst cooling until a dry homogenous powder is obtained of uniform brown colour.

Mixture B Procedure is similar to that in A, taking the precaution of working at a temperature not exceeding 40"C. The powder of mixture A is introduced into the hopper of an extruder and the powder of mixture B into the hopper of the other extruder.

The temperatures of the extrusion heads are, respectively,100 C for A and 90"C for B, the coextrusion head being adjusted to a temperature of 90"C.

At the outlet of the die, the mixed strap obtained is cooled by passage into a cold water bath.

The strap is then cut to the desired length, a closure system (buckle) is stapled to one of the ends.

The dimensional criteria fixed by the shape of the die are the following: - Overall width 15mm -Width of the insecticidal portion (brown) lOmm - Width of the fatty acid portion (yellow) 5mm -Thickness 3mm Example 9 Mixture A Parts by weight Amitraze [N-methyl, N' 2,4 8 Active xylyl N (N 2,4xylylforma- principle midovl) formamidine] Octyl adipate 25 Calcium stearate 2 Epoxidised soya oil Additive 5 Talc 12.5 White pigment 1 PVC homopolymer 46.5 Mixture B Methyl linoleate 1.5 Active Methyl linolenate principle 1.5 Methyl oleate 2 Butyl phthalate 20 Epoxidised soya oil 5 Calcium stearate Additive 2 Calcium carbonate 15 Black iron oxide 0.5 PVC homopolymer 52.5 The manufacture and extrusion then follow as described in Example 8.

With the specifications of the co-extrusion die, a white and black strap is obtained whose dimensions are as follows: - Overall width 20 mm - Width of the insecticidal portion (white) 15 mm - Width of the fatty acid portion (black) 5 mm - Overall thickness 2.5 mm Example 10 Mixture A Propoxu r N-methyl isopropoxy-2 10 Active carbamate phenyl principle Diethylphthalate 20 Dibutylphthaiate 5 Calcium stearate 5 Additive Epoxidised soya oil 5 Azodicarbonamide 1 Black iron oxide 0.5 PVC homopolymer 53.5 Mixture B Active Methyl linoleate principle 15 Dibutylphthalate 20 Calcium stearate 5 Calcium carbonate 15 Additive Yellow pigment 1 PVC homopolymer 44 The mixed strap obtained by coextrusion has the following specifications:: - Overall width 15 mm - Width of the insecticidal portion (black) 10 mm - Width of the fatty acid portion (yellow) 5 mm - Overall thickness 3 mm Clinical tests On an animal population including dogs and cats, of different age and breed, numerous clinical observations have shown the appearance of various skin infection due to the wearing of an insecticide collar.

The incorporation of free or esterified C18 to C22 unsaturated essential fatty acids, and in particular of C18 acids constituting vitamin F in an insecticidal collar enable these skin reactions to be minimised.

First comparison test The test consists of treating two populations (P1 and P2), or dogs of different sex, age and breed. Each population comprises 500 individuals.

The test is carried out over a period of 10 weeks, the condition of the animals being checked every two weeksafterthefixinvg of the collar.

The skin disorders taken into consideration during the experiment were: - peeling - erythemas - pruritis -falling hair at the level of the neck.

The composition of the collars ( /Q. by weight) studied is as follows: Collar Ct Collar C2 (according to the invention) DIMPYLATE 15 15 Neutral vitamin F 6 Isooctyl 20 20 Epoxidised soya oil 5 5 Calcium stearate 2 2 Red iron oxide 0.5 0.5 Micronised silica 2 2 PVC homopolymer 47.5 53.5 The collars of type C1 were fixed to the animals of population P1.

The collars of type C2 were fixed to the animals of population P2.

Table I groups the results of the observations, the figurs indicating the number of animals having signs of local intolerance.

TABLE I 2nd 4th 6th 8th 10th week week week week week Population P1 0 0 1 1 2 Population P2 3 3 4 5 6 Second comparison test An identical comparison test was carried out with two populations of cats P1 and P2 wearing collars C1 and C2 of the preceding Example The results are grouped in Table II.

TABLE II 2nd 4th 6th 8th 10th week week week week week Population P1 0 1 1 1 2 Population P2 4 4 5 6 7 In tests 1 and 2, the two compositions of collars C1 and C2 are 95% effective in eliminating parasites present on the animals (fleas and ticks).

The animals free of parasites were protected 100% during the 10 weeks of the experiment.

In this case, the phenomena of local intolerance were due only to the wearing of the collar and not due to excessive scratching or to mutilations caused by the presence of fleas.

Third test The six dogs which had worn collar C2 were selected (cf. test 1), and the seven cats which had worn collar C2 (cf. test 2).

All the animals showed skin reactions. Collar C2 was taken off and replced by collar C1.

The animals were observed for five weeks.

The results (cf. Table Ill) show that the formulation according to the invention (enriched with neutral vitamin F), enable the disappearance of the skin reaction in very little time.

TABLE Ill Number of 1st 2nd 3rd 4th 5th individuals week week week week week Dogs P2 6 2 2 1 1 1 CatsP2 7 3 2 2 2 2 As emerges from the foregoing, the invention is not limited in any way to those of its types of application and embodiments which have just been described more explicitly; it encompasses, on the contrary, all modifications which may come to the spirit of the technician skilled in the art, without departing from the framework or the scope of the present invention.

The term "vitamin F" as used herein refers to the the animal growth factors comprising one or more unsaturated fatty acids, particularly such acids with two or more double bonds (including Linoleic, linolenic and arachidonic acid, their esters and fats containing these acids).

Claims (19)

1. Anti-parasite collar for animals, comprising an insecticidal device formed from at least one insecticidal substance associated with a substrate selected among unsaturated essential fatty acids of C18 to C22 and their esters.

2. Device according to Claim 1, which is composed in addition, of the two following elements: a thermoplastic solid macromolecular support; adjuvants (plasticisers and/or inert fillers, and/or dyes, and/or deodorisers, and/or stabilisers and/or diffusion regulators.

3. Device according to Claim 1 or 2, wherein the insecticidal substance is selected from among organochlorine compounds and/or organophosphorus compounds and/or carbamates and/or pyrethrums and/orformamidines.

4. Device according to Claim 3, wherein the organochlorine substances, are selected from the group which comprises 2,2-dichlorovinyl phosphate and dimethyl phosphate, 1,2-dibromo-2,2 dichloroethyl phosphate and methyl phosphate (NALED), and 2-chloro (2,4,5-trichlorophenyl) vinyl phosphate and dimethyl phosphate (STIRIFOS).

5. Device according to Claim 3, wherein the organophosphorus substance is selected from the group which comprises O,O'-diethyl, O-(isopropyl-2 methyl-4 pyrimidinyl-6) thionophosphate (DIMPYLATE) and 0,0 diethyl O-(isopropyl-2 methyl-4 pyrimidinyl-6) phosphate (DIAZOXON).

6. Device according to Claim 3, wherein the carbamates are selected from among dimethyl-2,2 benzodioxol-1,3 ol-4 N-methyl carbamate (BENDIOCARD), isopropoxy-2 phenyl N-methyl carbamate (PROPOXUR), 1-naphthyl N-methyl carbamate (CARBARYL).

7. Device according to Claim 3 wherein the substances of the pyrethrum type are selected from amont a-cyano-3 phenoxybenzyl 2,2-dimethyl 3- (2,2-dichlorovinyl) cyclopropane carboxylate (CYPERMETHRIN), a-cyano-3 phenoxybenzyl 2- (4-chlorophenyl) 3-methyl butyrate (FENVALERATE), 5-benzyl, 3-furylmethyl 2,2-dimethyl 3-(2-oxo 2,3,4,5 tetrahydro 3-thienylidenemethyl) cyclopropane carboxylate (KADETHRIN), 3-phenoxybenzyl, 2,2-dimethyl, 3-(2,2-dichlorovinyl) cyclopropane carboxylate (PERMETHRINE), (3,4,5,6, tetrahydrophthalimidomethyl) chrysanthemate (NEOPYNAMIN).

8. Device according to Claim 3, wherein formamidines are selected from among N'-(4-chloro 0 tolyl) NN, dimethylformamidine (CHLORDIMEFORM) and N-methyl, N' 2,4xylyl N (N 2,4-xylylformamidoyl) formamidine (AMITRAZ).

9. Device according to any one of Claims 1 to 8, wherein the free or esterified unsaturated essential fatty acids, are selected from the group which comprises oleic acid, linoleic acid, linolenic acid, arachidonic acid, 11.14 eicosadienoic acid, docosahexaenoic acid and their linear or branched esters of C1 to C4.

10. Device according to any one of Claims 1 to 9 wherein as fatty acids, vitamin F is used.

11. Device according to any one of Claims 1 to 10 comprising 5 to 25% of insecicidal substance, 1 to 10% unsaturated essential fatty acid, 10 to 50% of macromolecular support and from 1 to 15% of various adjuvants.

12. Device according to any one of Claims 1 to 11, constituted essentially by association of DIMPYLATE-Vitamin F.

13. Collarfor animal according to Claim 1, in the form of two stripes bounded laterally to form a mixed double strap one strip containing the insecticidal substance, the other fatty acid, each of the two parts of the strip containing supports and additives suited to the insecticidal substance and to the selected unsaturated essential fatty acid.

14. Device according to Claim 13, wherein the mixed strip is obtained by hot co-extrusion.

15. Collar according to Claim 13, wherein the mixed strip is obtained by molding.

16. Collar according to any one of Claims 13 to 16, containing between 5 to 25% of insecticidal substane and 1 to 10% of fatty acids.

17. Collar according to any one of Claims 13 to 16, wherein each of the two parts of the mixed strap contains various dyes and/or pigments and/or photo-reflecting substances and/or luminescent substances.

18. Method of making an antiparasite collar according to any one of Claims 13 to 17, comprising preparing two different homogeneous mixtures, one containing between 5 to 25% of at least one insecticidal substance, and the other between 1 and 10% of at least one fatty acid, introducing these two mixtures separately into two hoppers of a double system extruder and effecting, at the moment of passage into the common extrusion head, a lateral weld.

19. Method according to claim 18, wherein the two mixtures are extruded in two different extruders connected at the output through a single extrusion head.