Patent Publication Number: US-4150109-A

Title: Devices for protecting animals from ectoparasites

Description:
This is a continuation, of application Ser. No. 673,994, filed Apr. 5, 1976 now abandoned, which in turn is a continuation-in-part application of Ser. No. 572,296, filed Apr. 28, 1975 (now abandoned). 
    
    
     The present invention relates to new arrangements which may be used round the necks of domestic animals and which are intended to protect the latter from ectoparasites, said arrangement consisting of a composition containing a plasticised vinyl polymer and diazinone or, preferably, diazoxone as insecticidal substance. 
     From French patent No. 1568198 by TAMOGAN Limited, compositions are known which contain a plasticised polymer and an insecticidal substance, such as DDVP, DIPTEREX and BROMEX, which can be used on parasitic insects; it is well known that DDVP works by releasing vapours. It is also known that DIPTEREX AND BROMEX are only slightly different from DDVP in their structure and that they work by giving off DDVP vapours arising from their decomposition. 
     The Applicants have now found that arrangements which were effective against parasitic insects on animals could work, not by their vapour, but by simple contact during the migratory movement of the parasites between the head and the other parts of the body of the host animal. 
     The Applicants have also found that diethyl O-(2-isopropyl-4-methyl-6-pyrimidinyl) thionophosphate, known under the name of Diazinone, and preferably diethyl O-(2-isopropyl-4-methyl-6-pyrimidinyl) phosphate, called diazoxone were particularly suitable for producing arrangements of this kind. 
     Compositions containing diazinone and plasticised polymer have also been described in said patent of Tamogan Limited, but these compositions consist solely of granules and it is neither stated nor suggested in said patent that such compositions could be used for providing an arrangement for use round the neck of a domestic animal. 
     The present invention therefore relates to an insecticidal arrangement intended to be fastened to the neck of an animal and containing the following elements: 
     A--diazinone and/or diazoxone as active principle, 
     B--a solid, macromolecular vinyl or vinylidene substance, 
     C--a plasticiser, 
     D--optionally, a dye, a pigment, a stabiliser and a deodorant, 
     E--optionally, a receptacle containing the rest of the insecticidal arrangement and consisting of a hollow section made of flexible plastic, which is insoluble in the active principle, which in turn has no, or virtually no solvent effect on the section, said section being sealed at its ends and having orifices all along its length, which is between 12 and 60 centimetres, and said receptacle being capable of carrying an attaching device, 
     F--optionally, a container, serving as case, which is impervious to the active principle. 
     The arrangements thus produced have, in comparison with those known which are based on DDVP, a much lower toxicity, owing to the fact that diazinone is five times less toxic than DDVP and, above all, because diazinone gives off virtually no toxic vapours, unlike DDVP, the latter having a vapour pressure over 100 times greater than that of diazinone. Diazoxone is even less toxic than diazinone. The LD.sub. 50 in the rat is 1600 mg/kg for diazoxone, whereas it is 450 mg/kg for diazinone. 
     Another advantage of the arrangements according to the invention lies in the much greater stability of diazinone and/or diazoxone compared with that of DDVP, particularly in the presence of humidity. The animal may go out in the rain or bathe without detriment to the arrangement, which is not the case with arrangements based on DDVP. 
     Another advantage lies in the very clean appearance of said arrangements, unlike those based on DDVP which are always viscous and unpleasantly oily to the touch. 
     Another advantage lies in the excellent effectiveness of the arrangements based on diazinone and/or diazoxone, which is clearly superior to that which can be obtained with those based on DDVP, Tetrachlorvinphos or Forpirate. 
     After an arrangement according to the invention, using diazoxone, has been moulded or extruded, the arrangement has virtually no unpleasant smell. Moreover, diazoxone is more active than diazinone. 
     The quantity of active principle present in the arrangement is preferably between 1 and 30% and, better still, between 5 and 20% by weight, that of the macromolecular substance between 30 and 80%, preferably 40 to 60%, and that of the plasticiser from 10 to 50%, preferably 20 to 35%. 
     The macromolecular substance preferably has a weight of more than 1000; it is selected from the homopolymers and copolymers obtained starting from vinyl chloride, vinyl acetate, vinyl acetals, vinylalcohol, vinylbenzene and divinylbenzene and vinylidene chloride; the copolymers may, in addition, contain additional components such as ethylenic, propylenic, butadienic, isoprenic, acrylic and methacrylic components. 
     Preferably, the macromolecular substance is a polymer or copolymer of a vinyl compound such as, for example, the polyvinyl halides. The particularly preferred macromolecular substances are polymers or copolymers of vinyl chloride. 
     The macromolecular substance preferably contains one or more plasticisers. 
     The plasticisers are liquid esters with a vapour pressure of less than 0.0001 mm/Hg at 25° C. Some nonrestrictive examples of plasticisers are: diethyl, dimethyl, dipropyl, dibutyl, dihexyl, dioctyl and didecyl phthalate, dibutyl, diamyl, dinonyl, dioctyl, and didecyl adipate, dipropyl, dibutyl, dibenzyl and dioctyl sebacate, diethyl, dipropyl and dibutyl citrate, triphenyl and tricresyl phosphate and the triglycerides. 
     The preferred plasticisers are dibutyl phthalate and dioctyl adipate, which make it possible to obtain an arrangement with good flexibility, on the surface of which the active principle appears rapidly and regularly. 
     Suitable stabilisers are all those known from diazinone, of which the following can be mentioned: epoxides such as epichlorohydrin, calcium, magnesium or potassium stearate, the laurates and palmitates of these same metals, chlorinated terphenyls and butoxy-propylene-glycol. The preferred stabilisers are calcium or magnesium stearate and epoxidised soya bean oil. 
     Suitable deodorants are all those which are capable of masking the smell of diazinone and the impurities it contains and which are acceptable to domestic animals. Examples of these are conmarine and vanilline. 
     The hollow section, if used, is preferably made from polyethylene, polypropylene or polyamide; its shape in cross section is not critical. It may be, for example, circular, elliptical, semicircular, lenticular, square or rectangular; its internal diameter is calculated with reference to the band it must hold and is therefore slightly greater than the thickness of the latter; the thickness of the walls of the section is preferably between 0.5 and 3 mm; forms and dimensions of this kind are easily obtained by extrusion. 
     The ends of the section are closed, for example, by welding or by one or more rivets. 
     The orifices preferably represent, in all, a total open surface of such a size that the ratio of the latter, expressed in cm 2 , to the weight of the insecticidal composition, expresed in grams, is between 0.5 and 1. 
     The shape of the orifices is not cricial; they may be circular, square, rectangular, lozenge-shaped, starshaped or any other desired shape. 
     The orifices are preferably distributed over not more than half the circumference of the hollow section, in order to prevent the active composition from coming into contact with the neck of the animal. 
     The attachment device may consist of a buckle fastened to one end of the section, the other end having a flat, flexible band, fitting the buckle, perforated or not, depending on the type of buckle, and made of leather or a plastic of the same kind as that of the section. The two ends of the section may also each have a buckle element which permit the section to be closed by joining the two elements. 
     The attachment device may also be a collection of hooks distributed along the section, allowing the latter to be attached to the usual collar of the animal to be protected. 
     The invention also related to processes for producing said arrangements. According to one of these processes, the constituents A, B, C and D are thoroughly mixed and the mixture is heated to 120° C. for 30 minutes in a preferably sealed container, in order to obtain a powder, which is optionally passed through a mill. This powder is used to form the arrangement desired, either by extrusion of by moulding in a material known to the specialists. The operation is carried out at a temperature preferably between 160 and 200° C. 
     According to another preparation process, the desired article is obtained directly, in the desired form and of the required dimensions, housed in its casing. According to this process, a solid material, with the desired form, consisting of macromolecular substance B, preferably plasticised, and an active liquid containing active principle A, and optionally a plasticiser and deodorant D, is placed inside a container F which serves as the casing, and which is impervious to the active liquid, and the volume of which is adapted so that the active liquid is in contact with at least part of the surface of material B; then the container is sealed in air-tight manner and the whole is stored at a temperature between 20° and 80° C. for a period, which is in inverse proportion to the temperature, of at least one day. 
     During storage, the active liquid passes, without any external intervention, into the solid material, wherein it is uniformly distributed by absorption. 
     The active liquid may contain, apart from the active principle and the optional constituents C and D, a solvent chosen from the succinic and maleic esters, such as the propyl, butyl, pentyl, hexyl, heptyl, octyl and decyl esters. 
     Material B may be prepared according to all the known methods of using and shaping plastics, such as injection moulding, pouring it on to a continuous belt, extrusion through a flat or annular draw-plate, calendering, drawing by dry or humid extrusion, followed by weaving or agglomeration. 
     In the techniques which use moulding, the solid material B is generally obtained directly in its final form and dimensions. 
     In the other techniques, a half-finished product is obtained, which is then shaped by cutting, sawing, forming, stamping, gluing, welding, etc. 
     The solid material may have any form, but it must give a ratio of surface available for contact with the active liquid/volume of at least 2 in the CGS system. The preferred shapes are plates, sheets, strips, tubes, sectioned rods, and, of these, particularly the forms of plates, tubes and strips may be used on a domestic animal. 
     Various structures may be used; the solid material B is, depending on the particular case: fibrous, alveolar, porous, spongy, foliated, felted or woven, but preferably compact or hollow. In the case of a compact mass, the ratio impregnation surface/volume may be increased by a non-smooth surface condition, such as undulating, grained, perforated or striated. 
     The form and the nature of the container are not critical, but it is necessary for it to be adapted so that the active liquid is in contact with at least part of the surface of material B, sufficient to permit, after the storage period, homogeneous penetration by the active liquid and uniform distribution of it in the material B; the container should be of such dimensions that all the material B and the active liquid can be held therein. It is desirable that the solid material B be totally bathed in the active liquid for most of the impregnation period. To satisfy this last condition, the container is preferably a small flexible bag, similar in form to the solid material B. The weight of active liquid to be absorbed according to the process is in the proportion of 0.1 to 2 parts of liquid to one part of B; when a solid material B is used which is in the form of a plate, sheet, strip of sectioned rod, this proportion is preferably between 0.2 to 1 part of liquid to one part of B; when a solid material B is used which is foliated, fibrous, felted or woven in structure, this proportion is preferably between 0.4 and 1.5 parts of liquid to one part of B; when a solid material B is used which is cellular or spongy in structure, this proportion is preferably between 1 and 2 parts of liquid to one part of B. 
     The order of introducing the solid mass and the active liquid into the container does not affect the impregnation mechanism, but it has been found that is was more practical to introduce the solid material first. 
     The container is given its air-tight seal by one of the methods which are well known in the packaging industry, such as, for example, corking, welding, glueing, crimping. The preferred method is welding. Depending on the nature of the casing material, welding is effected by direct thermal transfer, infra-red radiation or high-frequency current. According to a variant, the air-tight seal of the container is made after a vacuum has been created on the inside. The container thus emptied of air generally eliminated the risk of the arrangement exuding during storage. The container may also be emptied of air before sealing, on the condition that no air is allowed to go back in during sealing. 
     The minimum storage time for impregnating the solid material with all the active liquid depends on the nature and structure of the solid material B and the nature of the active liquid. Moreover, the minimum storage time decreases when the ratio surface/volume of solid material increases, when the weight ratio of solid/liquid increases, or when the temperature is increased. 
     The temperature at which storage takes place is preferably between +20 and +60° C. 
     The minimum time needed for impregnation is between 3 and 30 days. 
     A particularly interesting variant of the general process consists in using a solid material comprising a central cavity into which the active liquid to be absorbed is introduced. 
     This variant prevents direct contact between the liquid and the walls of the container and allows a greater rate of impregnation. According to this variant, the solid material B is flexible. Preferably, material B is made in the form of a flat bag or a tube with internal and external elliptical or, preferably, lenticular section. In the case of a tube with a lenticular section, one end is sealed by welding; the active liquid is introduced into it, then the other end is sealed by welding, letting as little air as possible into the tube. The whole is then placed in an air-tight container and stored as in the general case of the process. After total impregnation, the material B noticeably takes the form of a small flat strip. In this variant, the preferred embodiments use a material B in the form of tubes with a lenticular section, the dimensions of which are as follows: width (flattened tube) 1.5 to 6 cm, length 10 to 60 cm, thickness of the walls 1 to 5 mm. 
     In order to realise a variant of this kind, preferably a container is used which consists of a multilayer plastic sheet of the type known in the packaging field under the name &#34;complex&#34;. 
    
    
     EXAMPLES 1 to 4 
     Insecticidal collars for large or medium-sized dogs A-Composition 
     
         ______________________________________                                    
A-Composition                                                             
1.       diazinone            12%                                         
         dibutyl phthalate    22%                                         
         calcium stearate     2%                                          
         epoxidised soya bean oil                                         
                              4%                                          
         polyvinyl chloride   60%                                         
2.       diazinone            15%                                         
         dioctyl adipate      20%                                         
         magnesium stearate   2%                                          
         epoxidised soya bean oil                                         
                              3%                                          
         red pigment          1%                                          
         conmarine            1%                                          
         polyvinyl chloride   58%                                         
3.       diazinone            20%                                         
         dipropyl phthalate   10%                                         
         diheptyl adipate     10%                                         
         calcium laurate      1%                                          
         cyclohexene oxide    2%                                          
         white pigment        0.4%                                        
         green pigment        0.6%                                        
         copolymer of vinylidene                                          
         chloride/vinyl chloride (1:3)                                    
                              56%                                         
4.       diazinone            10%                                         
         dibutyl sebacate     5%                                          
         diheptyl adipate     25%                                         
         polyvinyl chloride   60%                                         
______________________________________                                    
 
    
     B-PRESENTATION 
     The mixture obtained is poured hot (180° C. approximately) on to a cold surface to be cut into thin strips, or is extruded to the desired form and dimensions. An attachment device is fixed on, either by welding of using hooks or rivets. The thin strip may also be placed in a hollow section, as stated above. The length of the collar thus produced is adjusted to fit the neck of the animal for which it is intended; it is also possible to make it only in a large size which is then adapted to fit the animal, by cutting and removing the superfluous part. The arrangement may also be made as a hollow band into which a ribbon or a strip of leather provided with an attachment device is passed; the hollow band is obtained by extrusion or by combining two flat, thin bands by welding or stitching; in the latter case, one of the two bands, for example the one intended to face the animal&#39;s neck, may be an inert material such as canvas, leather, or a polymer such as those given for the hollow sectioned case. 
     Over a period of six months, tests were performed on dogs of various sizes, with a simple band (without a case) according to the compositions A-1, comparing it with bands bases on commercial DDVP (10% plasticised polyvinyl chloride). The effectiveness on fleas is summarised in the following table: 
     
         ______________________________________                                    
Time from first use                                                       
                DDVP collars  Collar A-1                                  
______________________________________                                    
1 month         85%           100%                                        
2 months        63%           99%                                         
3 months        20%           92%                                         
4 months        11%           88%                                         
5 months         8%           77%                                         
6 months         5%           61%                                         
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     Similarly, very high effectiveness on ticks was also noted (total mortality 8 to 12 hours after fitting the collar) for more than 4 months for the A-1 collars, whereas the activity disappeared around the middle of the second month in the case of the DDVP collars. 
     A flee re-infestation test was carried out twenty weeks after the A-1 collars were fitted; elimination of fleas in a proportion of 72 to 91% was observed in the twenty-four hours that followed. 
     An analysis of several collars, made after 3 months, showed that the A-1 collars still retained nearly 65% of their active principle, whereas the DDVP collars had not more than 20 to 25% of this active substance. 
     EXAMPLES 5 to 7 
     Collars for cats and small dogs 
     
         ______________________________________                                    
A-Composition                                                             
5.        diazinone            10%                                        
          dibutyl phthalate    23%                                        
          calcium palmitate    2%                                         
          butyl epoxystearate  3%                                         
          yellow pigment       1%                                         
          polyvinyl chloride   61%                                        
6.        diazinone            8%                                         
          dihexyl phthalate    10%                                        
          dihexyl adipate      18%                                        
          octyl epoxystearate  2%                                         
          potassium stearate   1%                                         
          orange pigment       1%                                         
          polyvinyl acetate    20%                                        
          polyvinyl chloride   40%                                        
7.        diazinone            5%                                         
          dibutyl phthalate    15%                                        
          dioctyl adipate      15%                                        
          epoxidised soya bean oil                                        
                               1%                                         
          magnesium stearate   1%                                         
          blue pigment         0.3%                                       
          white pigment        0.7%                                       
          copolymer ethylene/vinyl                                        
          chloride (1:4)       62%                                        
______________________________________                                    
 
    
     B-PRESENTATION 
     The process is the same as in the preceding cases, but using smaller dimensions. 
     EXAMPLE 8 
     A flexible strip of polyvinyl chloride was used, pigmented with green, and plasticised with dibutyl phthalate (30% of the material plasticised). This strip measured 30 cm in length by 15 mm in width and 6 mm thick, and weighes 28 grams. 
     The strip had a buckle at one end and the other was perforated with small holes a centimetre apart, over a length of 10 centimetres. This strip was introduced into a small bag sealed by welding, consisting of a sheet containing of 30 micron layer of polyethylene and a 25 micron layer of aluminum turned to the outside. The internal dimensions of the bag were 32× 3 cm. Into the bag were poured 14 g of active liquid with the following composition: 
     
         ______________________________________                                    
       diazinone       4.2 g                                              
       dibutyl succinate                                                  
                       5.8 g                                              
       dibutyl phthalate                                                  
                       4.0 g                                              
______________________________________                                    
 
    
     The bag was sealed by welding, creating a vacuum inside, and was stored for 15 days at 40° C. After this period, the bag was opened. It was noted that no free liquid remained in the bag. The strip weighed about 42 g and analysis showed that it contained just over 9.7% of diazinone, i.e. 4.1 g. This strip was suspended at a temperature of 22± 2° C. and was wiped every two days with a non-woven cloth, new each time, which was then analysed. This operation showed that the quantity of active substance present in the active liquid, migrating to the surface, was, on average, between 17 and 18 mg/day and was still equal to 14.3 mg/day after four months of use. 
     EXAMPLES 9 and 10 
     Collars for cats and small dogs 
     
         ______________________________________                                    
A9-Composition of the collar based on Diazoxone                           
______________________________________                                    
Diazoxone                10%                                              
dibutyl phosphate        24%                                              
calcium stearate          2%                                              
epoxidised soya bean oil  3%                                              
pigment and perfume       1%                                              
polyvinyl chloride       60%                                              
______________________________________                                    
 
    
     
         ______________________________________                                    
B10-Composition of the collar based on Diazinone                          
______________________________________                                    
diazinone                10%                                              
dibutyl phosphate        24%                                              
calcium stearate          2%                                              
epoxidised soya bean oil  3%                                              
pigment and perfume       1%                                              
polyvinyl chloride       60%                                              
______________________________________                                    
 
    
     C-PRODUCTION 
     The two mixtures thus obtained are heated, then extruded or moulded under the same conditions, to the desired dimensions. 
     Over a period of 5 months, tests were carried out with the two arrangements, on dogs infested with fleas and ticks, and subjected to artificial re-infestation every week. 
     EFFECTIVENESS ON FLEAS 
     The comparative effectiveness of the two arrangements on fleas is summarised in the following table. 
     
         ______________________________________                                    
        % fleas            % fleas                                        
        killed   time taken                                               
                           killed time taken                              
        with     by arrange-                                              
                           with   by arrange-                             
        collar   ment A9 to                                               
                           collar ment B10 to                             
time since                                                                
        A9 after kill all the                                             
                           B10 after                                      
                                  kill all the                            
first use                                                                 
        24 hours fleas     24 hours                                       
                                  fleas                                   
______________________________________                                    
1 week  100%     12 hrs    100%   12 hrs                                  
15 days 100%     18 hrs    100%   18 hrs                                  
1 month 100%     20 hrs     98%   26 hrs                                  
2 months                                                                  
         96%     26 hrs     91%   30 hrs                                  
3 months                                                                  
         89%     30 hrs     80%   36 hrs                                  
4 months                                                                  
         82%     36 hrs     74%   48 hrs                                  
5 months                                                                  
         65%     48 hrs     59%   54 hrs                                  
______________________________________                                    
 
    
     EFFECTIVENESS ON TICKS 
     The comparative effectiveness of the two arrangements on ticks is summarised in the following table: 
     
         ______________________________________                                    
        % ticks            % ticks                                        
        killed   time taken                                               
                           killed time taken                              
        with     by arrange-                                              
                           with   by arrange-                             
        collar   ment A9 to                                               
                           collar ment B10 to                             
time since                                                                
        A9 after kill all  B10 after                                      
                                  kill all the                            
first use                                                                 
        24 hours the ticks 24 hours                                       
                                  ticks                                   
______________________________________                                    
1 week  100%     24 hrs    100%   24 hrs                                  
15 days  95%     32 hrs     93%   40 hrs                                  
1 month  85%     2 days     81%   21/2 days                               
2 months                                                                  
         78%     21/2 days  70%   31/2 days                               
3 months                                                                  
         65%     4 days     58%   5 days                                  
4 months                                                                  
         55%     5 days     46%   5% of ticks                             
                                  left after                              
                                  1 week                                  
______________________________________                                    
 
    
     EXAMPLES 11 and 12 
     Collars for medium sized and large dogs 
     
         ______________________________________                                    
All-Composition of collars based on Diazoxone                             
______________________________________                                    
diazoxone              15%                                                
dioctyl phthalate      20%                                                
magnesium stearate     2%                                                 
epichlorophydrin       3%                                                 
dye                    0.25%                                              
perfume                0.75%                                              
polyvinyl chloride     59%                                                
______________________________________                                    
 
    
     
         ______________________________________                                    
B12-Composition of Collars based on Diazinone                             
______________________________________                                    
diazinone              15%                                                
dioctyl phthalate      20%                                                
magnesium stearate     2%                                                 
epichlorohydrin        3%                                                 
dye                    0.25%                                              
perfume                0.75%                                              
polyvinyl chloride     59%                                                
______________________________________                                    
 
    
     C-PREPARATION 
     The process is performed by moulding or extrusion, as in the preceding cases. 
     Over a period of 5 months, tests were carried out on large dogs of different breeds infested with fleas and ticks. The animals are subjected to artificial reinfestation every week. 
     EFFECTIVENESS ON FLEAS 
     The following table summarises the comparative effectiveness of the two arrangements on fleas. 
     
         ______________________________________                                    
                            % fleas                                       
        killed    time taken                                              
                            killed  time taken                            
        with      by arrange-                                             
                            with    by arrange-                           
        collar    ment A11 to                                             
                            collar  ment B12 to                           
time in A11 after kill all the                                            
                            B12 after                                     
                                    kill all the                          
use     24 hours  fleas     24 hours                                      
                                    fleas                                 
______________________________________                                    
1 week  100%      12 hrs    100%    12 hrs                                
15 days 100%      18 hrs    100%    20 hrs                                
1 month 100%      24 hrs     97%    26 hrs                                
2 months                                                                  
         99%      26 hrs     93%    30 hrs                                
3 months                                                                  
         93%      30 hrs     85%    36 hrs                                
4 months                                                                  
         86%      32 hrs     78%    48 hrs                                
5 months                                                                  
         75%      48 hrs     69%    54 hrs                                
______________________________________                                    
 
    
     EFFECTIVENESS ON TICKS 
     The effectiveness is summarised in the following table: 
     
         ______________________________________                                    
        % ticks             % ticks                                       
        killed    time taken                                              
                            killed  time taken                            
        with      by arrange-                                             
                            with    by arrange-                           
        collar    ment A11 to                                             
                            collar  ment B13 to                           
time in A11 after kill all the                                            
                            B12 after                                     
                                    kill all the                          
use     24 hours  ticks     24 hours                                      
                                    ticks                                 
______________________________________                                    
1 week  100%      24 hrs    100%    24 hrs                                
15 days  93%      32 hrs     90%    40 hrs                                
1 month  80%      21/2 days  75%    3 days                                
2 months                                                                  
         75%      3 days     67%    31/2 days                             
3 months                                                                  
         67%      31/2 days  63%    4 days                                
4 months                                                                  
         58%      4 days     52%    5 to 6                                
                                    days                                  
______________________________________                                    
 
    
     These examples show that the effectiveness of the Diazoxone-based collar is greater than that of the Diazinone-based collar. 
     The invention relates to a composition to protect domestic animals from ectoparasites comprising a mixture of Diazinon and Diazoxon. 
     Advantageously the composition comprises of from 10 to 90% by weight of Diazinon and of from 90 to 10% by weight of Diazoxon. Better results are obtained when the composition comprises 40- 18%, say 60% of Diazinon and 60- 20%, say 40% of Diazoxon. 
     It has been now found that a mixture of Diazinon and Diazoxon is much more effective than each of them taken separately. This permits to reduce the quantity of active ingredient in a collar and thus to reduce the toxicity of the latter. The collar may then be used without danger for young cats (although they are sensitive to organo-phosphorous compounds) and for young dogs. 
     The synergy of Diazinon with Diazoxon may be explained as it follows: 
     Diazoxon has a very quick knock down effect. This paralysing and quick effect is not a 100% lethal one. On the contrary the lethal effect of Diazinon is very high, but Diazinon acts much more slowly than Diazoxon. 
     For instance fleas which continuously move on a dog may cross many times the neck of the dog bearing a Diazinon collar without being killed. 
     Fleas are paralysed practically immediately as they pass on the neck of a dog bearing a Diazoxon collar. Thus it has been noted that fleas fall down quickly on the white faience ground of a cage where a dog is encaged, said dog bearing a Diazoxon collar. But the fleas are only paralysed. They are not killed. Some of the fleas come back on the dog. 
     In the case of a collar made with a mixture of Diazinon and Diazoxon, the flea are first paralysed. They stay in the neighbourhood of the collar. This gives time for the lethal Diazinon to act. 
     The invention relates also to a composition for controling ectoparasites on domestic animals which comprises of from 2-25% of an insecticidal agent and of from 0,5 to 10% of an oil in a matrix of vinylresin. 
     Insecticidal agents which may be used are carbamates, organo-phosphorous compounds, organo-chlorine compounds, pyrethroids and mixtures thereof. 
     Carbamates useful in the compositions of the present invention are represented by the formula: ##STR1## wherein R 2  is hydrogen or lower alkyl, R 3  is lower alkyl and R 1  is aryl, substituted aryl, heterocyclid or substituted heterocyclic groups. The term &#34;lower alkyl,&#34; as used herein, refers to an alkyl group, branched or straight chain, having a chain length of one to six carbon atoms. The term &#34;aryl,&#34; as used herein, refers to an aryl group such as phenyl or naphthyl. The term &#34;substituted aryl&#34;, as used herein, refers to a phenyl or naphthyl group substituted with one or more groups such as lower alkyl, halogen, lower alkoxy, lower alkly-amino, lower dialkylamino or lower alkylthio. The term &#34;heterocyclic,&#34; as used herein, refers to a organic cyclic group having an oxygen atom, sulfur atom or nitrogen atom in the nucleus thereof and containing up to 12 carbon atoms. The term &#34;substituted heterocyclic,&#34; as used herein, refers to a heterocyclic group substituted with one or more groups such as lower alkyl, lower alkoxy, lower alkylthio, lower alkylamino, lower dialkylamino or halogen. 
     Typical of the carbamates which can be used in the present invention are 
     2-isopropylphenyl N-methyl carbamate, 
     2-isopropoxyphenyl N-methyl carbamate, 
     3-(1-methylbutyl) phenyl N-methyl carbamate, 
     3-(1-ethylpropyl) phenyl N-methyl carbamate, 
     6-chloro-3,4-xylenyl N-methyl carbamate, 
     4-methylthio-3,5-xylenyl N-methyl carbamate, 
     1-naphthyl N-methyl carbamate, 
     1-naphthyl N-ethyl carbamate, 
     1-naphthyl N-isopropyl carbamate, 
     1-naphthyl N-butyl carbamate, 
     1-naphthyl N-hexyl carbamate, 
     1-(4-chloronaphthyl) N-methyl carbamate, 
     1-(5,6-dihydronaphthyl) N-methyl carbamate, 
     1-(5,8-dihydronaphthyl) N-methyl carbamate, 
     4-benzothienyl N-methyl carbamate, 
     1-phenyl-3-methylpyrazol-5-yl N,N-dimethyl carbamate, dimethyl carbamate, 2-(N,N-dimethyl carbamyl)-3-methylpyrazol -5-yl N,N-dimethyl carbamate, and mixtures thereof. 
     The preparation of carbamates of the above formula has been previously described. See, for example, U.S. Pat. Nos. 2,903,478 and 3,203,853. 
     Some useful alkyl-, alkaryl-, aralkyl- and hetero-cyclic carbamates, are m-(1 ethylpropyl) phenyl methylcarbamate, m-(1methylbutyl) phenyl methyl carbamate, 2-dimethylamino- 5,6-dimethylpyrimidin-4-yl dimethylcarbamate, 4-methylthio- 3,5 xylyl-N-methyl carbamate, 2-(1,3-dixolan-2 yl) phenyl-N-methylcarbamate, 3-isopropyl-5-methylphenyl-N-methylcarbamate, 4-dimethylamino-3-tolyl-N methylcarbamate. 
     Useful organo-phosphorous compounds are phosphoric acid esters of the formula: ##STR2## wherein R 1  represents a member selected from the group consisting of alkyl, alkenyl, alkoxyalkyl and alkyl-mer-capto-alkyl radicals, R 2  represents a member selected from the group consisting of hydrogen, low alkyl and low alkenyl radicals, R 3  and R 4  represent low alkyl radicals, X represents a member selected from the group consisting of oxygen and sulphur, and Y represents a member selected from the group consisting of the direct link and sulphur. 
     Specific organo-phosphorous compounds are: 
     Bromophos 
     Phoxime 
     &#34;Phostex&#34; 
     &#34;Abate&#34; 
     Iodfenphos 
     Pyrimiphos 
     Azidithion 
     Fenchlorfos 
     Malathion 
     Parathion 
     Azinphos 
     Butonate 
     Nichlorfos 
     Crufomate 
     Aspon 
     Chlorothion 
     Fospirate 
     &#34;Dursban&#34; 
     Trichlorphon 
     Aldimithion 
     Azothoate 
     Phosphinon 
     Mevinphos 
     Crotoxyphos 
     Phosphamidon 
     Birlane 
     Fenitrothion 
     Trichlorometaphos 
     Fenthion 
     Fensulfothion 
     Zinophos 
     Dithion 
     Endothion 
     Mercaptophos 
     Vamidothion 
     Dimethoate 
     Formothion 
     Ethion 
     Phtalophos 
     Diazinon 
     II-Pyrethroides 
     Barthrine 
     Bioresmethrine 
     Tetrametrine 
     Resmethrine 
     Natural Pyrethrines 
     Allethrine 
     III-Organo-chlorine compounds 
     Bromodan 
     &#34;Perthane&#34; 
     Methoxychlore 
     Morestan 
     T d e 
     pentac 
     &#34;Dilan&#34; 
     Chlorfenethol 
     The composition according to the invention comprises 2-25% by weight of the insecticidal agent and more usually 2-15%. 
     The present composition comprises an oil, that is unsaturated (double bonds) aliphatic hydrocarbon compounds which, in general, has 10-24 carbon atoms, as well as the acid derivates thereof. Some useful oils are codliver oil, linseed oil, poppyseed oil, nut oil, olive oil, maize oil, oleic acid, orange oil, palm kernel oil, rape-seed oil, castor oil, rubsen oil, sesame oil, soya-bean oil, sunflower oil, peanut oil, cotton seed oil, hempseed oil, rosin oil, coconut oil, citronella oil, avocado oil, camphor oil, safflower oil, rape-seed oil, vaseline, mineral oils and mixtures thereof. 
     The composition comprises 0.5-10% of said oils and more usually 4-8% by weight. 
     The oil and the insecticidal agent are embedded in a vinylidene or vinylpolymer matrix which is of the same type as the above mentioned macromolecular substance. 
     It is critical that the double bonds of the oil be still present. Thus epoxydized oil is not appropriate. It has been found that such an oil with double bonds aids the insecticidal agent to entirely migrate from the composition. Thus it is possible to reduce the amount of insecticidal agent and the toxicity of the composition, while obtaining better results for the protection of an animal against ectoparasites. The duration of protection is enhanced. Residual collars contain no more toxic agent. 
     The following examples illustrate the invention. 
     EXAMPLE 11 
     Five collars (C1-C5) are prepared by extruding the compositions as mentioned in the following table. 
     
         ______________________________________                                    
Components % C1      C2      C3    C4    C5                               
______________________________________                                    
Diazinon     2       4       5     6     8                                
Diazoxon     8       6       5     4     2                                
P V C        62      62      62    62    62                               
Butyl Phthalate                                                           
             23      23      23    23    23                               
Epoxydized soya                                                           
bean oil     4       4       4     4     4                                
Dye          0.25    0.25    0.25  0.25  0.25                             
Vanilline    0.75    0.75    0.75  0.75  0.75                             
______________________________________                                    
 
    
     The results of experiments on dogs which are infested again each week are shown in Table I (see page 34). 
     It results from table I that the higher effectiveness is obtained for a weight Diazinon/Diazoxon ratio of 3/2. 
     EXAMPLE 12 
     Four collars (A1, B1, C6, C7) are prepared as in example 11. They have the compositions mentioned in the following table: (see page 35). 
     
                                           TABLE I                                 
__________________________________________________________________________
EFFECTIVENESS ON FLEAS                                                    
     % fleas or                                                           
           Time                         % fleas    % fleas                
     ticks taken by                                                       
                % fleas or                                                
                      Time taken                                          
                            % fleas                                       
                                  Time taken                              
                                        or ticks                          
                                             Time taken                   
                                                   or ticks               
                                                        Time taken        
     killed with                                                          
           C5 to kill                                                     
                ticks by C2 to                                            
                            or ticks                                      
                                  by C3 to                                
                                        killed                            
                                             by C4 to                     
                                                   killed                 
                                                        by C1 to          
     collar C5                                                            
           all the                                                        
                killed by                                                 
                      kill all                                            
                            killed by                                     
                                  kill all                                
                                        by C4                             
                                             kill all                     
                                                   by C1                  
                                                        kill all          
     after 24                                                             
           fleas or                                                       
                C2 after                                                  
                      the fleas                                           
                            C3 after                                      
                                  the fleas                               
                                        after                             
                                             the fleas                    
                                                   after                  
                                                        the fleas         
Time hours ticks                                                          
                24 hours                                                  
                      or ticks                                            
                            24 hours                                      
                                  or ticks                                
                                        24 hours                          
                                             or ticks                     
                                                   hours                  
                                                        or                
__________________________________________________________________________
                                                        ticks             
1 week                                                                    
     100%  12 h 100%  12 h  100%  12 h  100% 12 h  100% 12 h              
15 days                                                                   
     100%  22 h 100%  20 h  100%  18 h  100% 18 h  100% 20 h              
1 month                                                                   
      94%  26 h  97%  26 h  100%  22 h  100% 20 h    95%                  
                                                        26 h              
2 months                                                                  
      85%  30 h  89%  30 h   95%  26 h  100% 24 h   88% 30 h              
3 months                                                                  
      73%  36 h  76%  34 h   86%  30 h   94% 26 h   73% 34 h              
4 months                                                                  
      65%  42 h  68%  40 h   72%  34 H   86% 30 h   65% 40 h              
EFFECTIVENESS ON TICKS                                                    
1 week                                                                    
      96%  30 h  98%  26 h  100%  22 h  100% 20 h   95% 30 h              
15 days                                                                   
      90%  42 h  92%  40 h   93%  40 h   96% 32 h   89% 44 h              
1 month                                                                   
      79%  3,5 days                                                       
                 81%  3 days                                              
                             84%  3 days                                  
                                         88% 2 days                       
                                                    75% 3,5 days          
2 months                                                                  
      67%  4 days                                                         
                 70%  3,5 days                                            
                             71%  3,5 days                                
                                         76% 3 days                       
                                                    65% 4 days            
3 months                                                                  
      58%  5 days                                                         
                 59%  4 days                                              
                             62%  4 days                                  
                                         68% 3,5 days                     
                                                    56% 5 days            
4 months                                                                  
      48%  6-7 days                                                       
                 50%  5- 6 days                                           
                             54%  5-6 days                                
                                         60% 4 days                       
                                                    47% 1                 
__________________________________________________________________________
                                                        weeks             
 
    
     
         ______________________________________                                    
             Collar   Collar   Collar Collar                              
Components % A 1      B 1      C 6    C 7                                 
______________________________________                                    
Diazinon     15%                9%     6%                                 
Diazoxon              15%       6%     4%                                 
P V C        60%      60%      60%    62%                                 
Butyl Phthalate                                                           
             20%      20%      20%    23%                                 
Epoxydized soya                                                           
bean oil      4%       4%       4%     4%                                 
Dye           0.25     0.25     0.25   0.25                               
Vanilline     0.75     0.75     0.75   0.75                               
______________________________________                                    
 
    
     The results of experiments of dogs which are infested again each week are shown in tables II and III (see page 36). 
     EXAMPLE 13 
     20 collars E are prepared from: 
     
         ______________________________________                                    
components:             weight:                                           
______________________________________                                    
Diazinon                15%                                               
P.V.C.                  60%                                               
Dibutylphthalate        20%                                               
Epoxydized soya bean oil                                                  
                        4%                                                
Dye                     9.25%                                             
Vanilline               0.75%                                             
______________________________________                                    
 
    
     20 collars E 2 were prepared from the same components to which 7% by weight of sesame oil has been added. 
     Then the cinetic of Diazinon elimination was studied. 
     The collars were pulled out of their gas-tight bag and were immediately gas-chromatography dosed. 
     Then they were wiped with a filter-paper and put on a table. 
     
                                           TABLE II                                
__________________________________________________________________________
      % of para-                                                          
            Time taken                                                    
                  % of para-                                              
                        Time taken                                        
                              % of para-                                  
                                    Time taken                            
                                          % of para-                      
                                                 Time taken               
      sites killed                                                        
            by A1 to                                                      
                  sites killed                                            
                        by B1 to                                          
                              sites killed                                
                                    by C6 to                              
                                          sites  by C7 to                 
Time after                                                                
      with collar                                                         
            kill all                                                      
                  by B1 kill all                                          
                              by C6 kill all                              
                                          killed by                       
                                                 kill all                 
setting in                                                                
      A1 after                                                            
            the   after the   after 24                                    
                                    the para-                             
                                          C7 after                        
                                                 the                      
service                                                                   
      24 hours                                                            
            parasites                                                     
                  24 hours                                                
                        parasites                                         
                              hours sites 24 hours                        
                                                 parasites                
__________________________________________________________________________
EFFECTIVENESS ON FLEAS                                                    
1 week                                                                    
      100%  12 h  100%  12 h  100%   6 h  100%   12 h                     
15 days                                                                   
      100%  18 h  100%  18 h  100%   8 h  100%   18 h                     
1 month                                                                   
       95%  26 h  100%  20 h  100%  12 h  100%   20 h                     
2 months                                                                  
       90%  30 h   94%  26 h  100%  16 h  100%   24 h                     
3 months                                                                  
       84%  36 h   88%  30 h  100%  20 h   95%   26 h                     
4 months                                                                  
       73%  48 h   75%  34 h   98% 26 h                                   
                                     88%  30 h                            
5 months                                                                  
       60%  54 h   62%  48 h   93%  30 h   74% 36                         
__________________________________________________________________________
 
    
     
                                           TABLE III                               
__________________________________________________________________________
      % of para-                                                          
            Time taken                                                    
                  % of para-                                              
                        Time taken                                        
                              % of para-                                  
                                    Time taken                            
                                          % of para-                      
                                                Time taken                
      sites killed                                                        
            by A1 to                                                      
                  sites killed                                            
                        by B1 to                                          
                              sites killed                                
                                    by C6 to                              
                                          sites by C7 to                  
Time after                                                                
      with collar                                                         
            kill all                                                      
                  by B1 kill all                                          
                              by C6 kill all                              
                                          killed by                       
                                                kill all                  
setting in                                                                
      A1 after                                                            
            the   after the   after 24                                    
                                    the para-                             
                                          C7 after                        
                                                the                       
service                                                                   
      24 hours                                                            
            parasites                                                     
                  24 hours                                                
                        parasites                                         
                              hours sites 24 hours                        
                                                parasites                 
__________________________________________________________________________
EFFECTIVENESS ON TICKS                                                    
1 week                                                                    
      100%  22 h  100%  22 h  100%  14 h  100%  20 h                      
15 days                                                                   
       89%  40 h   94%  32 h  100%  20 h   96%  32 h                      
1 month                                                                   
       76%  3 days                                                        
                   82%  2,5 days                                          
                               98%  26 h   85%  2,5 days                  
2 months                                                                  
       65%  3,5 days                                                      
                   74%  3 days                                            
                               89%  32 h   74%  3 days                    
3 months                                                                  
       60%  4 days                                                        
                   65%  3,5 days                                          
                               82%  48 h   67%  3,5 days                  
4 months                                                                  
       51%  5- 6 days                                                     
                   56%  4 days                                            
                               75%  3 days                                
                                           60%  4 days                    
__________________________________________________________________________
 
    
     Every evening the collars were carefully wiped to eliminate any Diazinon on the surface. This increases the migration speed of Diazinon. (Under these wiping conditions a collar loses its activity within 3 months). 
     the collars were dosed for Diazinon each evening immediately after the wiping. 
     Table A gives the average percent of Diazinon remaining in the 20 conventional tested collars. Graph A shows also the results. 
     After 11 weeks Diazinon migrated no more out of the collar. The insecticidal agent content remained then constant at about 5%. This figure is also the final dose in any collar used for many months on a dog. 
     Table B and graph B give the average percent of Diazinon remaining in the collars when 9% of pea-nut oil has been added to the composition for the extrusion of collars. 
     Diazinon migrated almost entirely from the collars. The collars remain active for 19 weeks. 
     By the addition of the insaturated oil, all the insecticidal agent is used and the effect is longer. 
     Other experiments have shown that a collar with 15% by weight of Diazinon and 7% by weight of rape-seed oil is active during 6-7 months. Without any oil, the same collar is active during 4 months. 
     It is enough to have a 10-12% Diazinon content in a collar where unsaturated oil is present, to obtain a 4 months activity. The overall toxicity of the collar is reduced. 
     An epoxydized oil did not give the same unexpected results as the above mentioned oils. (See tables A and B). 
     
                       TABLE A                                                     
______________________________________                                    
Time in                                                                   
weeks    0      1      2    3    4    5    6    7                         
______________________________________                                    
% of                                                                      
Diazinon                                                                  
remaining in                                                              
         14.95  13.12  11.98                                              
                            10.91                                         
                                 10.03                                    
                                      9.24 8.51 7.85                      
the collar                                                                
Time in                                                                   
weeks    8      9      10   11   12   13   14                             
% of                                                                      
Diazinon                                                                  
remaining in                                                              
         6.97   6.31   5.68 5.23 5.17 5.15 5.16                           
the collar                                                                
______________________________________                                    
 
    
     
                                           TABLE B                                 
__________________________________________________________________________
Time in                                                                   
weeks   0  1  2  3  4  5  6  7  8  9  10                                  
__________________________________________________________________________
% of Diazinon                                                             
remaining in                                                              
        15.08                                                             
           12.85                                                          
              11.65                                                       
                 10.67                                                    
                    9.61                                                  
                       8.77                                               
                          7.98                                            
                             7.25                                         
                                6.58                                      
                                   5.71                                   
                                      5.17                                
the collar                                                                
Time in                                                                   
weeks   11 12 13 14 15 16 17 18 19 20 21                                  
% of Diazinon                                                             
remaining in                                                              
        4.42                                                              
           3.85                                                           
              3.28                                                        
                 2.70                                                     
                    2.21                                                  
                       1.76                                               
                          1.31                                            
                             0.84                                         
                                0.67                                      
                                   0.56                                   
                                      0.55                                
the collar                                                                
__________________________________________________________________________