the invention provides an injector device that allows for the sequential delivery of two incompatible components such as an antimicrobial formulation and a seal formulation into the teat canal of a non - human animal . the seal formulation and antimicrobial formulation are contained separately within a single injector device . this enables the product to be stored without affecting the stability of either component . the device also provides for the delivery of the antimicrobial formulation ahead of the seal formulation which effectively forms a physical barrier in the teat canal preventing any further entry into the teat canal . the seal formulation also prevents the possibility of the antimicrobial phase leaking or being expressed from the teat by gravitational or hydrostatic forces . the seal formulation may comprise a viscous oil - based cerate containing a high proportion of a heavy metal salt , bismuth subnitrate . the product teat seal ( trade mark of cross vetpharm group ) is described in detail in wo98 / 26759 and comprises a non - toxic heavy metal salt in a gel base . the base is a gel based on aluminium stearate . the gel preferably includes a vehicle such as liquid paraffin . the gel may also comprise a polyethylene gel . the gel may be based on low density polyethylene or on high density polyethylene . preferably , the heavy metal salt is present in an amount of greater than 40 %, preferably between 50 % and 75 % by weight , most preferably approximately 65 % by weight . the seal formulation prevents infection entering the udder via the teat or streak canal through a combination of its viscosity , density and adhesiveness . the antimicrobial or anti - inflammatory formulation may be selected from any one or more of a wide variety of compounds that are known to be effective for the treatment , prevention and elimination of mastitis and mastitis - causing organisms , including inter alia gram positive and gram negative bacteria , yeasts , fungi and rickettsias . the antimicrobial or anti - inflammatory materials may include inter alia beta lactam antibiotics such as penicillins and cephalosporins , beta lactam antibiotics potentiated by beta lactamase inhibitors such as clavulanic acid , polymyxins , glycopeptides , aminoglycosides , lincosamides , macrolides , pleuromutilins , “ fenicols ” such as chloramphenicol and florfenicol , tetracyclines , sulphonamides and potentiated sulphonamides such as mixtures of trimethoprim and one or more sulphonamide , quinolones and fluoroquinolones , ionophores , coumarins such as novobiocin , natural or synthetic peptides , lantibiotics , and other antimicrobial products of bacteria and other micro - organisms . other antimicrobials may be selected from any one or more of macrolide , lincosamide or pleuromutilin , erythromycin , spiramycin , tylosin , spiramycin , tilmicosin , lincomycin , spectinomysin , pirlimycin , tiamulin , potentiated sulphonamide mixtures , trimethoprim plus sulphadiazine , sulphadimidine , sulphadoxine , sulphadimethoxine or other sulphonamide , oxytetracycline , minocycline or doxycycline , fluoroquinolones , enrofloxacin , ciprofloxacin , norfloxacin , danofloxacin , difloxacin or marbofloxacin . the second component may be selected from any one or more of anti - inflammatory compounds , steroids such as prednisolone , betamethazone , dexamethasone , phenylbutazone , or non - steroids such as flunixin , ketoprofen , carprofen , vedaprofen , meloxicam , tepoxalin , eltenac , nimesulide or tolfenamic acid . other antimicrobial or anti - inflammatory compounds used in the treatment of intramammary infections in non - human animals may also be used . these antimicrobial or anti - inflammatory materials may be formulated either singly or in combinations of two or more compounds as liquids , cerates , solutions , suspensions emulsions or flowable powders in water , oil ( of animal , vegetable , mineral or other origin ) or other organic vehicles . other excipients such as solubilising , suspending or emulsifying agents , viscosity modifiers , surfactants , encapsulating agents and other means to adjust the rate at which the compound ( s ) is released from the formulation , buffers and such agents to maintain the ph of the formulation , anti - inflammatory agents such as various steroidal and non - steroidal compounds commonly used for this purpose , and various preservative agents commonly used in pharmaceutical preparations . referring to the drawings an initially to fig1 to 8 there is illustrated an injector device 1 according to the invention . the injector device 1 in this case comprises an inner barrel 2 and an outer barrel 3 . the outer barrel 3 has a nozzle 4 . the inner barrel 2 contains a first component comprising a seal 9 . the barrel 2 has a barrier or membrane 5 at its distal end . a plunger 6 is inserted into proximal end of the inner barrel 2 above the seal component 9 . an antimicrobial or anti - inflammatory component 10 is contained within the outer barrel 3 below the inner barrel 2 . in use , the nozzle 4 is inserted into a teat canal 20 of a non - human animal such as a cow . the inner barrel 2 is pushed through the outer barrel 3 by the plunger 6 to expel the antimicrobial or anti - inflammatory component 10 ( fig8 ( a )). when the antimicrobial or anti - inflammatory component 10 has been expelled ( fig8 ( b )) the plunger 6 on the inner barrel 2 is further depressed to expel the seal 9 from the inner barrel 2 . the pressure of the plunger 6 may be sufficient to release or rupture the barrier / membrane 5 on the inner barrel 2 allowing the seal 9 to be expelled from the injector device through the nozzle 4 and into the teat canal ( fig8 ( c )). rupturing means such as teeth 30 situated within the outer barrel 3 adjacent to the outlet nozzle 4 , may be used to release or rupture or open the barrier / membrane 5 . referring to fig9 and 9 ( a ) there is illustrated another injector which is similar to the injector of fig1 to 8 and like parts are assigned the same reference numerals . the injector device 1 comprises an inner barrel 2 and an outer barrel 3 . the outer barrel 3 has a nozzle 4 . in this case the barrier is released by an activator defined by a number of spikes 50 projecting upwardly to different lengths . the membrane / barrier has a portion 51 which is knocked - out by the spikes 50 to allow ejection of the seal component . the distal end of the inner barrel 2 has a seal or frill 53 which seals with the inner wall of the outer barrel 3 . referring to fig1 to 13 there is illustrated a further injector which is again similar to that of fig1 to 8 and like parts are assigned the same reference numerals . the injector device 1 comprises an inner barrel 2 and an outer barrel 3 . the outer barrel 3 has a nozzle 4 . in this case the barrier comprises a valve 60 at the distal end of the inner barrel 2 . an activator 61 projects upwardly from the lower wall of the outer barrel . in use , when the inner barrel 2 is in the configuration of fig1 the valve 60 is lifted by engagement with the activator 61 and allows the seal component 9 in the inner barrel 2 to pass through the injector nozzle 4 . when the plunger 6 is pushed down , the inner barrel 2 also travels down through the outer barrel 3 . the outside of the inner barrel 2 is a close fit in the outer barrel 3 so that the inner barrel 2 itself acts as a delivery device or plunger for delivery of the first component from the outer barrel 3 through the nozzle 4 . referring to fig1 to 16 there is illustrated another injector which is again similar to the injector of fig1 to 13 and like parts are assigned the same reference numerals . the injector device comprises an inner barrel 2 and an outer barrel 3 . the outer barrel 3 has a nozzle 4 . the inner barrel 2 contains a seal component 9 . a plunger 6 is inserted into proximal end of the inner barrel 2 above the seal component 9 . antimicrobial 10 is contained within the outer barrel 3 . in use , the nozzle 4 is inserted into a teat canal 20 . the inner barrel 2 comprises a distal end 74 having an outlet 75 and the barrier comprises a valve 70 which is received in the outlet 75 . the valve 70 is normally closed ( fig1 ( a ), ( b )) during delivery of the first component from the outer barrel 3 . an activator 71 projects upwardly from the lower wall of the outer barrel 3 . in use , when all of the first component has been delivered and the inner barrel 2 is in the configuration of fig1 ( c ) the valve 70 is released by engagement with the activator 71 and the seal component 9 in the inner barrel 2 is allowed to pass through side passageways 76 in valve through the outlet 75 and into the injector nozzle 4 . the inner wall of the inner barrel 2 is formed for engagement with the plunger 6 and comprises a locking ring 173 between the proximal and distal ends thereof . the inner barrel 2 comprises a distal portion 178 and a proximal portion 179 , the distal portion 178 having an internal diameter less than the internal diameter of the proximal portion 179 . the plunger 6 comprises a seal 77 which passes over the locking ring 173 of the inner barrel on assembly and the plunger 6 is thus sealingly engaged with the inner barrel 2 . the inner barrel 2 further comprises an external seal 72 for engagement with the internal wall of outer barrel 3 . the external seal 72 may for example comprise an integrally formed seal or an o - ring housed in a recess 172 in the external side wall of the inner barrel 2 . the external seal 72 is located near the distal end 74 of the inner barrel . the internal wall of the outer barrel 3 is formed for engagement with the inner barrel 2 and comprises a locking ring 73 between the proximal and distal ends thereof for engagement with the external seal 72 of the inner barrel 2 . the outer barrel 3 comprises a distal portion 78 and a proximal portion 79 . the distal portion 78 having an internal diameter less than the internal diameter of the proximal portion 79 . the external seal 72 passes over locking ring 73 of the outer barrel 3 on assembly and sealingly engages the outer barrel . the antimicrobial or anti - inflammatory formulation 10 is thus prevented from passing between the barrels as the plunger 6 is depressed . the valve 70 comprises a plurality of channels 76 which are exposed when the valve 70 is released to allow the seal component to pass out through the valve . thus upon releasing of the valve the channels 76 which define a passageway for the seal component are opened . the activator 71 defines a substantially cylindrical form defining a passageway and corresponds in form to the outlet 75 enabling it to be received in a portion of the outlet . the activator 71 is a close fit with the outlet 75 . in use the inner barrel 2 is pushed through the outer barrel 3 by the plunger 6 to expel the antimicrobial 10 ( fig1 ( a )). the outside of the inner barrel 2 has the geometry of the plunger 6 so that the inner barrel 2 itself acts as a plunger . when the antimicrobial 10 has been expelled ( fig1 ( b )) the plunger 6 on the inner barrel 2 is further depressed to expel the seal 9 from the inner barrel 2 . the valve 70 is released by engagement of the inner barrel with the activator 71 and the seal component 9 in the inner barrel 2 is allowed to pass through the valve passageways into the injector nozzle 4 and is expelled into the teat canal ( fig1 ( c )). referring to fig1 to 16 , and in particular fig1 ( b ) and ( c ) the operation of the valve is described in more details . when closed the valve 70 which is a close fit with the outlet 75 rests in the outlet and prevents any mixing of the components in the outer and inner barrels ( fig1 ( b ) and 16 ( b )). when the activator 71 is received in the outlet 75 ( fig1 ( c ) and 16 ( c )) the valve is released and the passageways 76 in the valve are opened to enable the seal component to pass into the valve passageways 76 through the passageway defined by the activator 71 and into the injector nozzle 4 . the engagement of the activator 71 with the outlet of the inner barrel 2 provides for alignment of the respective passageways 76 of the valve and the activator before the valve is released and the seal component is allowed to pass from the inner barrel . the respective passageways 76 of the valve and activator provide a closed and isolated pathway for the seal component to pass from the inner barrel 2 directly into the injector nozzle 4 . one advantage of a valve type barrier of this embodiment is that there is not risk of any part of the barrier becoming mobile . the barrier is retained with the injector . referring to fig1 to 18 there is illustrated an injector device 81 of an alternative embodiment of the invention ( which is similar to the injector of fig1 to 16 and like parts are assigned the same reference numerals ). the injector device 81 comprises a barrel 3 , an outlet nozzle 4 and a plunger 6 . two incompatible components 9 and 10 are placed within the barrel 3 of the injector device 81 . the two components such as an antimicrobial 10 and a seal 9 are separated from one another by a barrier / membrane . the antimicrobial 10 is placed in the barrel 3 and a seal 9 is placed in a receptacle 86 such as a bag which is defined by an outer membrane 87 which provides the barrier . the receptacle 86 may comprise a capsule into which the seal is filled on manufacture . the capsule may then be readily dropped into the barrel 3 of the injector before a plunger 6 is inserted . when the nozzle 4 of the device 81 is inserted into a teat canal 16 a user depresses the plunger 6 to effect delivery of the antimicrobial 10 from the injector device into the teat canal ( fig1 ( a )). after the antimicrobial 10 is expelled from the injector device further pressure applied to the plunger results in puncturing or bursting of the receptacle 86 allowing egress of the seal 9 which is delivered into the teat canal ( fig1 ( b )). fig1 ( d ) shows the position of a seal formulation 9 and antimicrobial formulation 8 on delivery into the teat of a non - human animal . the injector device may comprise rupturing means such as sharp teeth 88 at the distal end of the barrel 3 to assist in puncturing or bursting the receptacle 86 . it will be appreciated that for ease of manufacture and use , the receptacle 86 may be attached to the plunger 6 . in this case the receptacle is unable to come into contact with the rupturing device until substantially all of the first component has been expelled from the device . when delivering a seal 9 and antimicrobial or anti - inflammatory formulation 10 into the teat canal of a non - human animal the injector device is typically positioned vertically below the teat with the delivery nozzle uppermost . the seal formulation 9 has a much higher specific gravity than the antimicrobial or anti - inflammatory formulation 10 and therefore the receptacle containing the seal formulation remains at the lower end of the barrel 3 containing the antimicrobial or anti - inflammatory formulation during the delivery of the antimicrobial or anti - inflammatory formulation into the teat . in this case the receptacle comes into contact with the rupturing device only when substantially all of the antimicrobial or anti - inflammatory formulation has been delivered into the teat . referring to fig1 and 20 there is illustrated another injector device 90 of the invention . the injector device 90 comprises an inner barrel 92 and an outer barrel 93 . the outer barrel 93 has a nozzle 94 . the inner barrel 92 comprises a breakable / burstable barrier or membrane at its distal end and a plunger 98 at its proximal end . antimicrobial 10 is contained within the outer barrel 93 . in use , the nozzle 94 is inserted into a teat canal 16 . the inner barrel 92 is pushed through the outer barrel 93 to expel the antimicrobial ( fig2 ( b )). this procedure may be facilitated by a flange 97 around the proximal end of the inner barrel 92 and a flange 99 around the proximal end of the outer barrel 93 . when the antimicrobial 10 has been expelled ( fig2 ( c )) the plunger 98 on the inner barrel 92 is depressed to expel the seal 9 from the inner barrel 91 . the pressure of the plunger 98 is sufficient to burst or rupture the barrier / membrane 96 on the inner barrel 92 allowing the seal 9 to be expelled from the injector device through the nozzle 94 and into the teat canal ( fig2 ( c )). alternatively rupturing means such as sharp teeth situated within the outer barrel 93 at its aperture into the nozzle , ruptures the barrier / membrane 96 . a seal 96 may be provided at the front end of the inner injector barrel 92 to provide a positive seal . the inner injector may be moulded with a weak burstable barrier / membrane 95 across the outlet aperture . it will be appreciated that the seal portion of the formulation may be manufactured in one facility and subsequently combined with the anti - bacterial portion of the formulation at a later stage , in the same or another facility . the invention is not limited to the embodiments hereinbefore described which may be varied in detail .
the invention relates to a method and device for treating or preventing or suppressing a disease or condition in a non - human animal . the method comprises the steps of providing a single delivery device containing two components for sequential delivery from the delivery device . a first component is delivered from the single delivery device into a teat canal of a non - human animal and subsequently the second component is delivered from the single delivery device into the teat canal . the components are delivered without substantial mixing of the components .